IWA affiliate
Status and Role of Water Reuse
An International View
Prepared by:
James Crook, Ph.D., P.E.
Jeffrey J. Mosher
Jane M. Casteline
August 2005
Global Water Research Coalition
Alliance House
12 Caxton Street
London SW1H 0QS
United Kingdom
Phone:
+ 44 207 654 5545
www.globalwaterresearchcoalition.net
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Global Water Research Coalition:
Global cooperation for the generation of water knowledge
GWRC is a non-profit organization that serves as a collaborative mechanism for water research.
The benefits that the GWRC offers its members are water research information and knowledge.
The Coalition focuses on water supply and wastewater issues and renewable water resources:
the urban water cycle.
The members of the GWRC are: the Awwa Research Foundation (US), CRC Water Quality and
Treatment (Australia), EAWAG (Switzerland), Kiwa (Netherlands), Suez Environment- CIRSEE
(France), Stowa - Foundation for Applied Water Research (Netherlands), DVGW – TZW Water
Technology Center (Germany), UK Water Industry Research (UK), Veolia- Anjou Recherché
(France), Water Environment Research Foundation (US), Water Research Commission (South
Africa), WateReuse Foundation (US), and the Water Services Association of Australia.
These organizations have national research programs addressing different parts of the water
cycle. They provide the impetus, credibility, and funding for the GWRC. Each member brings a
unique set of skills and knowledge to the Coalition. Through its member organizations GWRC
represents the interests and needs of 500 million consumers.
GWRC was officially formed in April 2002 with the signing of a partnership agreement at the
International Water Association 3rd World Water Congress in Melbourne. A partnership
agreement was signed with the U.S. Environmental Protection Agency in July 2003. GWRC is
affiliated with of the International Water Association (IWA).
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Disclaimer
This study was jointly funded by GWRC members. GWRC and its members assume no
responsibility for the content of the research study reported in this publication or for the opinion
or statements of fact expressed in the report. The mention of trade names for commercial
products does not represent or imply the approval or endorsement of GWRC and its members.
This report is presented solely for informational purposes.
Copyright © 2005
by
Global Water Research Coalition
ISBN 90-77622-10-1
AwwaRF 2006, Used With Permission
Preface
Water reuse is of growing interest to the members of the Global Water Research Coalition
(GWRC). As a result, water reuse was selected as a priority area in the GWRC’s research
agenda.
In 2004, the GWRC Board of Directors decided to initiate a project with the aim of reviewing the
present knowledge of water reuse and to organize a workshop to develop a phased research
strategy. The WateReuse Foundation (WRF) was selected as GWRC’s lead organization for
this research area. As a first step, WRF proposed to conduct a workshop on water reuse
research needs. The objective of the workshop, which was held in Nieuwegein, the Netherlands
in April 2005, was to develop a research strategy on water reuse for the GWRC. As a
resource for the workshop, GWRC sponsored the development of this report to assess the
current status of water reuse internationally. GWRC members contributed to the project by
providing expert knowledge concerning water reuse in their countries and regions of the world.
This report was prepared by James Crook, Ph.D., a water reuse consultant based in the United
States, and Jeffrey J. Mosher and Jane M. Casteline, WRF staff members. The report was
reviewed by GWRC member representatives.
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Contents
Page
1.0 Introduction.............................................................................................................................. 1
2.0 Overview................................................................................................................................... 1
2.1 Microbial and Chemical Concerns ..................................................................................... 2
2.1.1 Microbial and Chemical Concerns ........................................................................... 2
2.1.2 Chemical Constituents............................................................................................. 5
2.1.3 Treatment Technologies ......................................................................................... 11
3.0 Country/Region Summaries.................................................................................................... 13
3.1 United States..................................................................................................................... 13
3.1.1 Applications............................................................................................................ 13
3.1.2 Regulations ............................................................................................................. 15
3.1.3 Public Perception/Acceptance ................................................................................ 18
3.2 Canada ............................................................................................................................. 22
3.3 Latin America (Central and South America)................................................................... 23
3.4 Europe.............................................................................................................................. 25
3.4.1 Applications............................................................................................................ 25
3.4.2 Technology ............................................................................................................. 27
3.4.3 Common Issues ...................................................................................................... 27
3.4.4 Regulations ............................................................................................................. 28
3.5 Middle East and North Africa ......................................................................................... 29
3.6 Southern Africa (South Africa and Namibia)................................................................... 37
3.6.1 South Africa ........................................................................................................... 37
3.6.2 Namibia .................................................................................................................. 38
3.7 Australia........................................................................................................................... 39
3.7.1 Applications............................................................................................................ 39
3.7.2 Regulations ............................................................................................................. 40
3.7.3 Public Perception/Acceptance ................................................................................ 41
3.8 Far East ............................................................................................................................ 41
4.0 Desalination of Seawater and Brackish Water....................................................................... 45
4.1 Status ................................................................................................................................ 45
4.2 Technologies.................................................................................................................... 47
4.2.1 Membrane Processes .............................................................................................. 47
4.2.2 Thermal Processes .................................................................................................. 49
4.2.3 Other Processes ...................................................................................................... 50
4.3 Other Factors ................................................................................................................... 51
4.3.1 Economics .............................................................................................................. 51
4.3.2 Concentrate Disposal.............................................................................................. 52
4.3.3 Energy Needs ......................................................................................................... 52
4.4 Desalination Research Needs ........................................................................................... 52
4.4.1 “Desalination Roadmap” Findings ......................................................................... 53
4.4.2 GWRC Survey Results ........................................................................................... 53
4.4.3 Results of the California (USA) Desalination Task Force Report ......................... 55
5.0 GWRC Survey Results .......................................................................................................... 56
5.1 Key Factors of Success Identified by GWRC Members ................................................. 56
5.1.1 Public Trust ............................................................................................................ 56
5.1.2 Pricing and Economics ........................................................................................... 57
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5.1.3 Public Health and Environmental Protection ......................................................... 58
5.1.4 Guidelines and Regulations.................................................................................... 59
5.1.5 Planning, Management, and Applications.............................................................. 60
5.1.6 Improved Technologies and Monitoring ................................................................ 61
5.2 Priority Water Reuse Research Needs............................................................................. 62
5.2.1 Southern Africa ...................................................................................................... 62
5.2.2 Australia ................................................................................................................. 64
5.2.3 Europe .................................................................................................................... 66
5.2.4 United States........................................................................................................... 67
5.3 Potable Reuse Issues........................................................................................................ 70
5.3.1 Southern Africa ...................................................................................................... 70
5.3.2 Australia ................................................................................................................. 70
5.3.3 Europe .................................................................................................................... 71
5.3.4 United States........................................................................................................... 71
5.4 Ongoing, Planned, and Completed Research Projects..................................................... 72
6.0 Summary and Conclusions .................................................................................................... 73
7.0 References.............................................................................................................................. 76
Appendix A – GWRC Water Reuse Survey Form
Appendix B – Completed GWRC Surveys by Region
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1.0 Introduction
This report summarizes the current status of water reuse and is intended to serve as a background
document in support of a Global Water Research Coalition (GWRC) Water Reuse Research
Strategy Workshop that was held April 11-13, 2005 at Utrecht, the Netherlands. The purpose of
the workshop was to identify and prioritize research needs related to water reuse to assist in the
identification of research projects appropriate for consideration for collaborative funding by
GWRC members. Based on selected published information and results of a recent GWRC
member survey, the report addresses the status of water reuse in regions/countries where reuse is
practiced, trends and drivers of reuse, current and ongoing research; and specific research needs.
2.0 Overview
The treatment of wastewater and other impaired waters and their subsequent beneficial use
commonly is called water reclamation and reuse, although different terms are used in various
countries/regions. For example, some frequently-used terms include “water reuse,” “water
recycling,” “water purification,” “reclaimed water,” “recycled water,” “reuse water,” and
“repurified water.” For the purposes of this report, the following definitions apply:
•
•
•
•
Reclaimed water = treated municipal wastewater and other impaired waters that are used
for beneficial purposes.
Water reuse = the use of reclaimed water for any purpose.
Indirect potable reuse = augmentation of a raw water supply with reclaimed water
followed by an environmental buffer. The mix typically receives additional treatment
before distribution as drinking water. The definition of indirect potable reuse could be
further broken down to “planned indirect potable reuse” (i.e., discharge of reclaimed water
to a drinking water source with the intended purpose of augmenting the potable supply) or
“unplanned indirect potable reuse” (i.e., discharge of treated wastewater to a drinking
water source as a disposal method rather than as a purposeful means of augmenting a
potable water supply.) The distinction between planned and unplanned indirect potable
reuse varies from country to country and often is not well-defined.
Direct potable reuse = introduction of reclaimed water directly into a water distribution
system, without intervening storage (pipe-to-pipe).
Identification of “planned” versus “unplanned” or “incidental” water reuse projects may be
important from a regulatory standpoint but is of lesser importance when considering the practical
acceptability of the practice, as the result is the same (i.e., wastewater is reused for a beneficial
purpose). Unplanned or incidental reuse is widely practiced throughout the world. A schematic
diagram depicting different types of water reuse is provided in Figure 1.
Water reclamation and reuse began on a large scale about 150 years ago when cities began using
flush toilets and sewerage systems. By the late 1800s, there were several “sewage farms” in
Europe and elsewhere where untreated wastewater was used for agricultural irrigation; in most
cases, the main purpose was to provide for disposal of the wastewater, and any agricultural
benefits from the farms were incidental. This method of disposal was replaced by discharge of
effluent to rivers, streams, and other waters with the advent of biological treatment processes in
the early 1900s. In the first half of the 20th century, reclaimed water was used almost exclusively
for agricultural irrigation. Advances in treatment technology, public health, microbiology, and
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Figure 1. Schematic of Water Use
Industrial
water use
Atmospheric water vapor
Water
treatment
Municipal
use
Precipitation
Waste water
reclamation/reuse
surface
water
Irrigation
Surface water
Ground water
Ground
water
Ground water recharge
Potable
reuse
Source: Courtesy of Frans Schulting, GWRC
monitoring resulted in additional uses of reclaimed water. Today, reclaimed water applications
range from pasture irrigation, where minimal treatment is acceptable, to potable reuse, where
extensive treatment is needed to meet drinking water standards. Agricultural irrigation continues
to be the major use of reclaimed water in most developing countries, while the trend in some
industrialized countries has shifted to landscape irrigation and other uses in urban areas,
industrial and commercial applications, and potable reuse. Lazarova and Asano [2005] recently
summarized water reuse activities in several countries (Table 1).
Water reuse regulations and guidelines vary considerably from country to country and even
within countries. Most countries that engage in water reuse have either developed their own
standards or guidelines or use those developed by others (e.g., the World Health Organization
Guidelines for the Use of Wastewater for Agriculture and Aquaculture [World Health
Organization, 1989]). In general, regulations in industrialized countries tend to be more
restrictive than those in developing countries. Technical capability and social, economic, and
cultural conditions influence regulatory requirements. Arguments for less restrictive standards
are often predicated upon a lack of documented health hazards rather than upon any certainty
that hazards are small or nonexistent. In the absence of a common interpretation of scientific
data, selection of water quality criteria will continue to be somewhat subjective and inconsistent.
Although regulations and guidelines vary among and within countries, they generally are based
on health protection from microbial pathogens and, thus, become more restrictive as the expected
degree of human contact with the reclaimed water increases. The comparative stringency of
regulations and guidelines for a range of uses is indicated in Table 2.
2.1 Microbial and Chemical Concerns
2.1.1 Microbial Pathogens
The most common concern associated with the reuse of treated municipal wastewater is the
potential transmission of infectious disease, primarily by enteric pathogens. Many of the
pathogens potentially present in untreated wastewater are well-documented in the literature
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Table 1. Overview of Water Reuse (Selected Countries)
Country/
State
Argentina
Australia
Belgium
Canada
Chile
Chinab
Egyptb
France
Indiab
Israel
Italy
Japan
Jordan
Kuwait
Namibia
Mexicob
Moroccob
Oman
South
Africa
Saudi
Arabia
Spain
Sweden
Tunisia
United Arab
Emirates
UK
USA
- Arizona
- California
- Florida
a
Water
Reuse
Activitya
Reuse
Guidelines/
Regulations
medium
high
medium
medium
low
medium
medium
medium
high
intensive
medium
high
high
intensive
medium
medium
medium
high
Yes
Yes
No
Yes
Percent Water Consumption by
Sector
Water Reuse
Applications a
Urban
16
12
Industry
9
6
Agriculture
75
70
Irrigation
++
++
No
No
Yes
No
Yes
Yes
Yes
Yes
Yes
No
No
No
Yes
11
5
5
6
15
5
29
14
19
22
37
28
17
5
5
68
11
18
8
73
3
7
33
17
3
2
3
5
3
2
7
84
77
86
12
92
64
53
64
75
60
68
78
92
93
+
++
+
++
+++
+++
++
++
++
+
+
+++
++
++
high
Yes
17
11
72
++
+
intensive
Yes
9
1
90
+++
++
high
low
medium
Yes
18
30
3
68
4
83
++
+
++
+
Yes
13
35
14
intensive
Yes
24
10
67
+
++
medium
high
high
intensive
high
Yes
Yes
Yes
Yes
Yes
65
11
8
44
2
40
+
++
++
+++
+++
++
+
+
++
++
Potable
+
+
+
Subjective evaluation based on literature: +++ numerous, ++ occasional and + isolated projects.
Countries using raw sewage for irrigation.
b
Source: Adapted from: Lazarova and Asano [2005]
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Urban
3
+
++
+++
+
++
+
+
+
+
+
++
+
Table 2. Comparative Stringency of Regulations/Guidelines Depending on Type of Reuse
Stringency of Regulations
and Guidelines
Type of Use
Potable reuse
Agricultural irrigation of food crops eaten raw (direct contact
between water and edible portion of crop)
Unrestricted recreational impoundments (full body contact
allowed)
Unrestricted urban irrigation (park, playground, schoolyard,
residential lawn irrigation)
Restricted urban irrigation (golf courses, roadway medians, etc.)
Restricted recreational impoundments (boating, fishing, incidental
contact allowed)
Agricultural irrigation of food crops (no direct contact between
water and edible portion of crop)
Aquaculture
Industrial reuse (cooling water)
Processed food crops (commercial processing to destroy
pathogens)
Environmental reuse (wetlands, stream flow augmentation)
Construction uses (soil compaction, dust control, etc.)
Agricultural reuse on non-food crops (fodder, fiber, & seed crops)
More Stringent
L
L
L
L
L
L
L
L
L
L
L
Less Stringent
[Blumenthal et al., 2004; 2000; Carr et al., 2004; Hurst et al., 1989; National Research Council,
1996; National Research Council, 1998; National Research Council, 2004; Radcliffe, 204; Sagik,
et al., 1978; U.S. Environmental Protection Agency, 2004]. The principal source of pathogens in
wastewater is the feces of infected individuals, but some enteric pathogens also affect other
animals and therefore have animal reservoirs; thus, the types and concentrations of pathogens in
any particular wastewater depend to a large extent on the health of the contributing population.
For example, helminth infections are far less common in Europe, Australia, and the United States
than in China, India, and the Middle Eastern countries.
Of equal concern to microbiologists and public health officials are new, emerging, or reemerging
pathogens. Emerging infectious diseases have been defined as those whose incidence in humans
have increased within the past two decades or threaten to increase in the near future [Institute of
Medicine, 1992]. Selected emerging and reemerging waterborne pathogens are listed in Table 3.
Some – but not all – of the pathogens listed in Table 3 have been found in municipal wastewater.
Fungi (i.e., yeasts and molds) are ubiquitous in the environment, although only a few of the more
than 100,000 known fungi are known to be pathogenic to humans [National Research Council,
2004]. Given the ubiquity of molds and fungi in water samples, some experts indicate that
research is needed to clarify their role in the transmission of waterborne diseases.
Two types of aquatic microorganisms, aeromonads and cyanobacteria, may be of concern for
potable reuse systems if sufficient nutrients are present to create blooms of these organisms
resulting in increased production of toxin [National Research Council, 1998]. The possible
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Table 3. Emerging and Reemerging Waterborne Pathogens of Public Health Concern
Bacteria
Viruses
Protozoa
Aerobacter
Adenoviruses
Acanthamoeba
Aeromonas hydrophila
Astrovirus
Cryptosporidium parvum
Campylobacter (including
C. jejuni, C. coli, and
related species
Coxsackieviruses
Cyclospora cayetanensis
Echoviruses
Giardia lamblia
Enteroviruses
Microsporidia
Hepatitis viruses
Toxoplasma gondii
Helicobacter pylori
Legionella spp.
Mycobacterium avium
complex
Norwalk/Caliciviruses
Rotavirus
Pathogenic Escherichia coli
Pseudomonas aeruginosa
Yersinia enterocolitica
Source: Adapted from: National Research Council [2004]
health significance of aeromonads led the Netherlands to develop drinking water guidelines for
the concentration of the organisms after treatment and in the distribution system [van der Kooij,
1993]. In response to the potential health threat from cyanobacteria, the Engineering and Water
Supply Department of South Australia developed interim guidelines for acceptable numbers of
cyanobacteria in drinking water supplies [El Saadi et al., 1995].
While molecular techniques are used to assess water for certain pathogens, they generally are
organism-specific and often only indicate the presence or absence of genetic material in the
sample – not concentration or viability. Thus, their utility in evaluating the safety of reclaimed
water for any particular use is somewhat limited at the present time. It is impractical to monitor
reclaimed water for all microbial pathogens, and indicators for waterborne pathogens are
universally used. The principal indicators are total coliform, fecal coliform, Escherichia coli,
and enterococci. Bacteriophage also has been used as an indicator of enteric viruses. None of
the existing indicators or combination of existing indicators is capable of predicting the presence
of all waterborne pathogens. Water reuse regulations generally require a combination of
treatment requirements and water quality criteria that have been shown by research or operating
experience to produce acceptable product water.
2.1.2 Chemical Contaminants
With a few exceptions (e.g., where municipal wastewater contains significant amounts of
potentially toxic industrial wastes), there are minimal health concerns associated with chemical
constituents where reclaimed water is used for irrigation or other nonpotable applications.
Pesticides, heavy metals, and organic chemicals are usually reduced to acceptable limits by
conventional wastewater treatment and would not be expected to present any risks to health from
contact or inadvertent infrequent ingestion of reclaimed water. The health effects related to the
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chemical constituents are of primary concern with regard to potable reuse. Both organic and
inorganic constituents need to be considered where reclaimed water is utilized for food crop
irrigation, where reclaimed water from irrigation or other beneficial uses reaches potable
groundwater supplies, or where organics may bioaccumulate in the food chain (e.g., in
aquaculture applications).
Some inorganic and organic constituents and their potential significance in water reclamation
and reuse are summarized below.
•
Biodegradable organics: Biodegradable organics can create aesthetic and nuisance
problems. Organics provide food for microorganisms, adversely affect disinfection
processes, make water unsuitable for some industrial or other uses, consume oxygen, and
may cause acute or chronic health effects if reclaimed water is used for potable purposes.
•
Stable organics: Some organic constituents tend to resist conventional methods of
wastewater treatment. If not eliminated or reduced to low levels in reclaimed water, their
presence may limit the suitability of reclaimed water for some applications, particularly
potable reuse. Total organic carbon (TOC) is the most common monitoring parameter for
gross measurement of organic content in reclaimed water used for potable purposes. TOC
is used as a measure of treatment process effectiveness; at the present time, it is not
possible to specify a maximum contaminant level for TOC based on health effects data
[National Research Council, 1998].
•
Nutrients: Nitrogen, phosphorus, and potassium are essential plant nutrients for plant
growth, and their presence normally enhances the value of the water for irrigation. When
discharged to the environment, nitrogen and phosphorus can lead to the growth of
undesirable aquatic life. When applied at excessive levels on land, the nitrate form of
nitrogen will readily leach through the soil and may cause groundwater concentrations to
exceed drinking water standards.
•
Hydrogen ion concentration: The pH of wastewater affects disinfection efficiency,
coagulation, metal solubility, and alkalinity of soils. Normal pH range in municipal
wastewater is 6.5 to 8.5, but industrial wastes may have pH characteristics well outside of
this range.
•
Heavy metals: Some heavy metals such as cadmium, copper, molybdenum, nickel, and
zinc accumulate in crops to levels that are toxic to consumers of the crops. Heavy metals
in reclaimed water that has received at least secondary treatment are generally within
acceptable levels for most uses; however, if industrial wastewater pretreatment programs
are not enforced, certain industrial wastewaters discharged to a municipal wastewater
collection system may contribute significant amounts of heavy metals.
•
Dissolved inorganics: Excessive salinity may damage some crops. Specific ions such as
chloride, sodium, and boron are particularly toxic to some crops. Sodium may pose
permeability problems. Residential use of water in the U.S. typically adds about 300 mg/L
of dissolved inorganic solids, although the amount added can range from approximately
150 mg/L to more than 500 mg/L [Metcalf & Eddy, 2002].
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•
Residual chlorine: Excessive amounts of free available chlorine may cause damage to
some sensitive crops. However, most chlorine in reclaimed water is in a combined form,
which does not generally cause crop damage. The reaction of chlorine with organics in
water creates a wide range of disinfection byproducts (DBPs), some of which may be
harmful to health when ingested over the long term. DBP levels – as well as pesticide and
heavy metal levels – in tertiary treated wastewater generally are below maximum
contaminant levels (MCLs) in drinking water standards [National Research Council,
1998].
•
Suspended solids: Suspended matter can shield microorganisms from disinfectants and
react with disinfectants such as chlorine or ozone to lessen disinfection effectiveness. It is
essential to remove suspended solids where ultraviolet radiation is used as the disinfection
process to destroy or inactivate microbial pathogens to low or undetectable levels in
reclaimed water. Suspended solids can lead to sludge deposits and anaerobic conditions if
discharged to the aquatic environment. Excessive amounts of solids cause clogging in
irrigation systems or accumulate in soil and affect permeability.
Effects of physical parameters (e.g., pH, color, temperature, and particulate matter) and chemical
constituents (e.g., chlorides, sodium, and heavy metals) are well known, and recommended limits
have been established for many constituents [National Academy of Sciences-National Academy
of Engineering, 1973; Radcliffe, 2004; U.S. Environmental Protection Agency, 1981; Westcot
and Ayers, 1985; Water Pollution Control Federation, 1989; U.S. Environmental Protection
Agency, 2004]. The effect of organic constituents in reclaimed water used for crop irrigation
may warrant attention if industrial wastes contribute a significant fraction to the wastewater.
Highly toxic organic compounds have been found in reclaimed water used for potable reuse,
such as N-nitrosodimethylamine and 1,4-dioxane. At present, no surrogate parameters or group
of surrogate parameters have been identified that are capable of indicating the presence of many
individual or types of organic compounds having health significance. Traditional measures of
organic matter in wastewater, such as BOD, COD, and TOC are used as measures of treatment
efficiency and general water quality. TOC is not an adequate indicator of the safety of reclaimed
water related to chemical constituents, since many chemicals are carcinogenic or otherwise
hazardous at levels far below commonly measured TOC levels.
There has been a great deal of interest and, in some cases, concern, regarding human health
effects associated with pharmaceuticals, hormones, and other organic wastewater contaminants.
Chemicals that interfere with endocrine systems of humans and wildlife are termed endocrine
disrupting compounds (EDCs). Chemicals that elicit a pharmaceutical response in humans are
termed pharmaceutically active compounds (PhACs). EDCs and PhACs are not mutually
exclusive classifications, as some, but not all, PhACs are also EDCs. Endocrines are chemicals
used by organisms to regulate important metabolic activities, such as ion balance, reproduction,
basal metabolism and “fight or flight” responses, through changes in hormones secreted by the
thyroid, parathyroid, pituitary, adrenal, sex, and other glands. At the present time, more than
4,000 compounds have been reported to show endocrine disrupting properties, primarily in
relation to estrogen effects [Global Water Research Coalition, 2003a], and more than 60 PhACs
have been identified that impact the endocrine system of animals or humans in nanogram/liter
(ng/L) or lower concentrations in the ecosystem. Pharmaceuticals and personal care products
(PCPs) are sometimes called PPCPs, which comprise a very broad, diverse collection of
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thousands of chemicals, including prescription and over-the-counter drugs, fragrances,
cosmetics, sun screen agents, diagnostic agents, and many other compounds.
Available data collected by member agencies of the GWRC indicate that EDCs are found in all
types of waters (i.e., groundwater, surface water, drinking water, and treated wastewater) with
concentrations of different classes of EDCs ranging from ng/L to µg/L levels [Global Water
Research Coalition, 2003b]. In recognition of the fact that monitoring the entire spectrum of
potential EDCs in water and wastewater would be cost-prohibitive, the GWRC developed a
priority list of EDCs (presented in Table 4) that would provide a basis for credible analytical
determination of EDCs in water. It is understood that the priority list of EDCs is dynamic and
additions or deletions to the list may be made as additional information becomes available.
Table 4. GWRC Priority List of Endocrine Disrupting Compounds
Pesticides and Herbicides
Aldrin
Cyhexitin
DDT
DDE
DDD
Dieldrin
Endosulphan-sulphate
α-Endosulphan
β-Endosulphan
Endrin
Heptachlor
Heptachlor epoxide
Isodrin
Lindane (?-BHC)
Hormones
Metoxychlor
Parathion
Simazine
Terbutylazine
Tributylin
Vinclozolin
Industrial Chemicals
17α-ethinylestradiol
17β-estradiol
Estriol
Estrone
Bisphenol A
Glycol ethers
p-Nonylphenol
p-Octylhenol
PCB (total)
Phthalates: DBP, DEPH
Heavy Metals
Cadmium
Source: Global Water Research Coalition [2003a]
Most of the research to date has been directed at the presence, concentration, and effects of
pharmaceuticals, personal care products, and endocrine disrupting compounds – or their
metabolites – on the aquatic environment, where these constituents have been shown to have
adverse effects on aquatic animals such as frogs and fish. Less is known about the presence,
concentration, and human health effects (including additive/synergistic effects) associated with
these chemicals resulting from long-term ingestion of potable water, although it has been
reported that several researchers who conducted risk evaluations concluded that there is no
appreciable risk to humans at the low levels of the chemicals found in drinking water [Global
Water Research Coalition, 2004]. Mons et al. [2003] estimated that the lifetime intake of
pharmaceuticals from drinking water, based on drinking 2 liters/day for 70 years, is far below the
therapeutic dose. However, most experts agree that toxicological data are lacking on the human
and environmental significance of PhACs with regard to subtle long term effects, and thus,
exposure to these substances should be minimized.
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Toze [2005] conducted an extensive literature review on chemical constituents in reclaimed
water and concluded there is a minimal potential health impact from EDCs in reclaimed water
used for nonpotable purposes due to their low concentration and very small potential doses
resulting from contact with the water. Similarly, a Global Water Research Coalition report states
that exposure to PhACs and EDCs that may occur during recreation in surface water containing
reclaimed water is considered to be negligible due to the low frequency of exposure and low
quantity of water that would be ingested [Global Water Research Coalition, 2004]. In contrast,
Rajapakse et al. [2002] reported that experiments using a combination of 11 xenoestrogens (i.e.,
man-made estrogenic chemicals) and 17β-estradiol, each present at a level below its noobserved-effect concentration, demonstrated that the xenoestrogens were able to modulate
significantly the estrogenic effects of 17β-estradiol. The authors cautioned that additive
combination effects of xenoestrogens deserve serious consideration.
Many commonly used pharmaceuticals are ubiquitous in wastewater effluents. In conventional
wastewater treatment plants, they can be removed or reduced in concentration by microbial
degradation, adsorption to particulates that are removed during wastewater treatment, or by
biotransformation. Research on wastewater samples collected at several wastewater treatment
plants in California indicate that secondary effluent contains estrogenic hormone concentrations
comparable to those that cause vitellogenesis (i.e., feminization) in fish and that filtration of
secondary effluent removes approximately 70% of the hormones from secondary effluent
[Huang and Sedlak, 2001]. The synthetic oral contraceptive 17α-ethinylestradiol is suspected, in
combination with the steroidal estrogens 17β-estradiol and estrone, of causing vitellogenin
production in male fish. Desbrow et al. [2002] identified estrone, 17α-ethinylestradiol, and 17βestradiol as compounds associated with high estrogenic activity in treated municipal wastewater
in the United Kingdom. A partial list of PhACs and PCPs frequently found in wastewater
effluents and the aquatic environment is provided in Table 5.
The chemicals listed in Table 6 are based on a literature review by Drewes et al. [2003] for
selected endocrine disrupting compounds found in secondary treated municipal wastewater. All
are generally found – if at all – at ng/L levels except for the alkylphenols, which in total may be
in the µg/L range. The literature reviewed indicates that activated sludge secondary treatment
removes EDCs more effectively than secondary treatment using the trickling filter process.
Further, long retention times and nitrification/denitrification during activated sludge treatment
enhanced removal of EDCs. While conventional secondary and tertiary treatment efficiently
removes some pharmaceuticals, removal or reduction of others is highly variable [Buser and
Muller, 1999; Ternes, 1998]. Advanced wastewater treatment processes such as reverse osmosis
are capable of removing most EDCs and PhACs to undetectable levels in the product water.
Ozone also is an effective treatment process to reduce the concentrations of many of these
chemicals to low levels.
A review of the scientific literature did not provide any information on whether or not
pharmaceuticals and endocrine disrupting compounds become concentrated on vegetation or in
soil via irrigation with reclaimed water. Drugs detected in the environment are generally in the
µg/L - ng/L range and many have short half-lives (i.e., they do not persist for long periods in the
environment) and may not pose much acute risk [Daughton and Ternes, 1999].
There is increasing concern regarding antibiotic resistance in microbial pathogens. There is a
correlation between antibiotic use and the appearance of antibiotic-resistant bacteria in the
AwwaRF 2006, Used With Permission
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Table 5. Pharmaceutically Active Compounds and Personal Care Products Observed in
Treated Wastewater and/or the Aquatic Environment
Area of Application
Compounds
Pharmaceutically Active Compounds
Analgesics/anti-inflammatory drugs
Acetaminophen, Acetylsalicylic acid,
Diclofenac, Dimethylaminophenazone,
Fenoprofen, Ibuprofen, Ketoprofen,
Meclofenamic acid, Naproxen, Paracetamol,
Phenazone, Tolfenamic acid,
Antibiotics
Amoxicillin, Ciprofloxacin, Erythromycin,
indometacine, oxytretacyclin,
Sulfachlorpyridazine, Sulfamerazine,
Sulfamethazine, Sulfamethoxazole,
Sulfamethoxine, Sulfathiazole, Trimethoprim
Anti-epileptics
Carbamazepine, Primidone
Anti-neoplastic agents
Cyclophosphamide, Ifosfamide
Beta-blockers
Betaxolol, Bisoprolol, Carazolol, Matoprolol,
Nadolol, Propranolol, , Sotolol, Timolol
Lipid regulators
Bezafibrate, Clofibric acid, Fenofibric acid,
Gemfibrozil
Tranquillizers
Diazepam
Esrogens
17α-ethinylestradiol
Diagnostic agents
Amidotrizoic acid, Diatrizoate, Iomeprol,
Iopamidol, Iopromide
Personal Care Products
Nitromusks
Musk ketone, Musk xylene
Polycyclic musks
Celestoide, Galaxolide, Tonalide
Anti-bacterial agents
Triclosan
Source: Drewes et al. [2001]; Global Water Research Coalition [2004]
AwwaRF 2006, Used With Permission
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Table 6. Typical Concentration Ranges of Selected Endocrine Disrupting
Chemicals in Secondary-Treated Municipal Wastewater
Compound
Concentration In Secondary Effluent
Estrogen (ng/L)
Testosterone (ng/L)
Estrone (ng/L)
17β-estradiol (ng/L)
Estriol (ng/L)
17α-ethinylestradiol (ng/L)
Bisphenol A (ng/L)
Alkylphenols (total) (µg/L)
1.4 – 76
50
1.4 – 7.6
2.7 – 48
<0.2 – 37
<0.3 – 9
20 – 50
27 – 98
Source: Adapted from Drewes et al. [2003]
environment. The spread of resistant genes between different bacterial species is enhanced in the
presence of biomass and nutrients, and thus is an important factor in the spread of resistance in
matrices containing wastewater. An increasing level of antibiotic resistance of microflora in the
gastrointestinal tract of humans may be transferred to infectious pathogens and severely affect
the effectiveness of medically-prescribed antibiotics. More study is needed to determine the
extent and gravity of antibiotic-resistance in microorganisms and microflora as a result of the
presence of PhACs in municipal wastewater.
The Global Water Research Coalition [2003c; 2004] categorized some knowledge gaps and
research needs related to EDCs and PhACs in water, including the following:
•
•
•
•
•
Impacts and risks of EDCs and PhACs towards public health and the environment;
Analytical methods and monitoring techniques;
Removal of EDCs and PhACs via wastewater treatment;
Source control methods; and
Occurrence and fate of EDCs and PhACs in the water cycle.
2.1.3 Treatment Technologies
Untreated municipal wastewater contains pathogenic microbial pathogens, high levels of
suspended and dissolved inorganic and organic substances, and concentrations of chemical
constituents that may make the water unacceptable for some uses. Although untreated
wastewater is used for irrigation in some countries, it usually is the result of ineffective control
or regulation and is not an authorized practice in most regions of the world. All countries that
have water reuse guidelines or regulations require at least some level of treatment for any
reclaimed water application.
Wastewater treatment levels generally are classified as preliminary, primary, secondary, tertiary,
and advanced. Tertiary treatment could be defined as treatment processes beyond secondary
treatment. In the U.S., tertiary treatment commonly refers to inclusion of a filtration process,
usually preceded by a chemical addition step, between secondary treatment and disinfection. All
other processes beyond secondary are usually termed advanced wastewater (AWT) processes;
thus, tertiary treatment and advanced wastewater treatment are sometimes used interchangeably.
AwwaRF 2006, Used With Permission
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Primary and secondary treatment processes are well understood and widely used throughout the
world. In general, mechanical treatment processes (e.g., activated sludge, trickling filters, etc.)
are favored in industrialized countries while natural treatment processes (e.g., stabilization
ponds, lagoons, etc.) are favored in developing countries. Stabilization pond systems are
particularly widespread in the Middle East and some other areas due to climate, land availability,
ease of operation and maintenance, and technical feasibility. Secondary treatment can
significantly reduce the concentration of bulk organics and many inorganic constituents, but
most processes have little effect on reducing microbial pathogens. An exception is stabilization
ponds, which – if properly designed and operated – have been shown to effectively reduce
bacterial, viral, and protozoan parasites to low levels. Wetlands systems, usually following
secondary treatment, have been used as a treatment process in several locations with mixed
results. Some treatment processes, such as soil aquifer treatment, may provide either secondary
or tertiary treatment depending on treatment processes that precede them. Small decentralized or
onsite treatment systems using intermittent sand filters, recirculating media filters, treatment
through soil systems – sometimes using plants in the treatment process, aquaculture processes,
and wetlands systems have also been used effectively [Tchobanoglous et al., 1998].
Tertiary treatment (in this report, tertiary treatment means filtration of secondary effluent
through media or membranes followed by disinfection) and advanced treatment processes have
experienced significant technical advances in the last 10-15 years. For most nonpotable
applications of reclaimed water, wastewater receives either secondary or tertiary treatment,
depending on the particular use. Secondary treatment generally is acceptable when human
contact with the water does not occur, while regulations generally require tertiary treatment
where human contact with the water is likely or expected to reduce health risks or for aesthetic or
environmental reasons. Membrane processes, usually microfiltration or ultrafiltration, are
becoming more prevalent as replacements for media filtration processes at water reclamation
facilities in the U.S., Australia, Japan, and elsewhere, as are membrane biological reactor (MBR)
processes.
AWT may be used for some nonpotable applications of reclaimed water (e.g., where nutrient
removal is required or where extremely high quality water is needed for some industrial uses)
and is used in several potable reuse schemes to produce drinking quality product water. Typical
AWT processes include membrane processes – particularly nanofiltration or reverse osmosis,
carbon adsorption, chemical precipitation, ion exchange, biological nutrient removal, and
advanced oxidation processes such as H202/UV. A review of the literature by the GWRC
indicated that ozone and advanced oxidation are promising processes for the removal of some
pharmaceuticals in drinking water treatment [Global Water Research Coalition, 2004]
For most uses of reclaimed water, disinfection is a critical process to destroy or inactivate
microbial pathogens. Chlorine (i.e., gaseous chlorine, hypochlorite, or chloramines) is the most
common disinfectant used at water reclamation facilities in the U.S., while chlorine dioxide is
used to a lesser extent in the U.S. and other countries, including China, France, and Israel
[Lazarova and Asano, 2005]. In recent years, UV has replaced chlorine as the disinfection
process of choice at many reclamation plants. UV is now cost-competitive with chlorine, safer
to use, does not result in hazardous disinfection byproducts, and is effective against parasites
such as Cryptosporidium and Giardia and many bacteria. While UV generally is effective for
inactivating viruses, some viruses, such as adenoviruses, require dosages significantly greater
than those normally used for reclaimed water [Thompson et al., 2003; Thurston-Enriquez et al.,
AwwaRF 2006, Used With Permission
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2003]. Where UV is used for disinfection, chlorine is often added to the reclaimed water prior to
its entrance to a pipeline distribution system to prevent microbial regrowth, reduce the formation
of biological growths and slimes in pipelines, and to oxidize organic matter to prevent odors. In
the U.S., the National Water Research Institute and Awwa Research Foundation have jointly
published a manual on the design and operation of UV systems for water reuse systems requiring
a high level of disinfection [National Water Research Institute, 2003].
Other disinfection technologies, such as ozone, have not gained widespread use at water
reclamation facilities. Ozone is a powerful oxidant, but is not used extensively for disinfection at
water reclamation facilities, principally due to its high operational and maintenance costs. It is
used at some potable reuse facilities where, in addition to its disinfection ability, it has the
advantage of removing color and oxidizing potentially toxic chemicals to non-hazardous
substances. Membranes, although not strictly termed disinfection processes, do remove some
pathogens based on size exclusion. For example, microfiltration effectively removes parasites
such as Cryptosporidium and Giardia and many bacteria, but it is not an effective barrier against
viruses. Reverse osmosis (RO), on the other hand, is capable of removing all pathogens from the
water, including viruses.
3.0 Country/Region Summaries
3.1 United States
3.1.1 Applications
Water reclamation and reuse is a long-established practice in the United States. Historically, the
largest-volume uses of reclaimed water were those that do not require high quality water (e.g.,
pasture or nonfood crop irrigation) and were often perceived as a method of wastewater disposal.
Reclaimed water is now valued as a resource and, in recent years, the trend has shifted toward
higher level uses such as urban irrigation, toilet and urinal flushing, industrial uses, and indirect
potable reuse. As droughts and population increases continue to stress the availability of fresh
water supplies, reuse of municipal wastewater will play an ever-increasing role in helping to
meet water demands. Reclaimed water is used for many purposes, ranging from pasture
irrigation to augmentation of potable water supplies. Reclaimed water applications currently
practiced in the U.S. are listed in Table 7.
Currently, there is no national inventory of water reuse projects in the U.S. Thus, while accurate
information on the number and type of projects and quantity of reclaimed water used is not
available, it is generally accepted that more than 7.6 Mm3/d (2.6 billion gallons/day) of
reclaimed water currently are used throughout the country. Most of the water reuse projects are
located in the southeast (Florida), southwest (Texas and New Mexico) and west (Arizona,
California, Colorado, and Nevada). California and Florida are by far the leading states in terms
of reclaimed water operations and volume of water reused. These two states account for about
one-half of the total usage of reclaimed water in the U.S. on an annual basis. The types and
percentages of reclaimed water used in California and Florida are presented in Figures 2 and 3,
respectively.
Irrigation is the most prevalent use of reclaimed water on a nationwide basis. In recent years,
urban uses have experienced a high growth rate, while agricultural irrigation has experienced
AwwaRF 2006, Used With Permission
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Table 7. Uses of Reclaimed Water in the United States
Category of Use
Specific Types of Use
Landscape irrigation
Parks, playgrounds, cemeteries, golf courses, roadway
rights-of-way, school grounds, greenbelts, residential and
other lawns
Agricultural irrigation
Food crops, fodder crops, fiber crops, seed crops,
nurseries, sod farms, silviculture, frost protection
Nonpotable urban uses (other than
irrigation)
Toilet and urinal flushing, fire protection, air conditioner
chiller water, commercial laundries, vehicle washing,
street cleaning, decorative fountains and other water
features
Industrial uses
Cooling, boiler feed, stack scrubbing, process water
Impoundments
Ornamental, recreational (including full-body contact)
Environmental uses
Stream augmentation, marshes, wetlands, fisheries
Groundwater recharge
Aquifer storage and recovery, seawater intrusion control,
ground subsidence control
Potable water supply augmentation
(indirect potable reuse)
Groundwater recharge, surface water augmentation
Miscellaneous
Aquaculture, snow-making, soil compaction, dust
control, equipment washdown, livestock watering
Figure 2. California Water Reuse by Type
Figure 3. Florida Water Reuse by Type
Source for Figures 2 and 3: U.S. Environmental Protection Agency, 2004.
only moderate growth. There are hundreds of water reclamation plants supplying reclaimed
water to literally thousands of individual landscape irrigation sites. While there are few potable
reuse projects, they typically represent large quantities of reclaimed water. For example, the
Orange County Water District’s Groundwater Replenishment System project, currently under
construction in Southern California, will recharge about 380,000 m3/d (100 mgd) upon build out.
AwwaRF 2006, Used With Permission
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3.1.2 Regulations
There are no federal regulations governing water reclamation and reuse in the U.S.; regulations
are developed and implemented at the state government level. This has resulted in differing
standards among states that have developed reuse criteria. No states have regulations that cover
all potential uses of reclaimed water, but several states have extensive regulations that prescribe
requirements for a wide range of end uses of the reclaimed water. Other states have regulations
or guidelines that focus on land treatment of wastewater effluent, emphasizing additional
treatment or effluent disposal rather than beneficial reuse, even though the effluent may be used
for irrigation of agricultural sites or public access lands. Less than half of the states in the U.S.
have adopted regulations specifically related to water reuse.
The absence of state criteria for specific reuse applications does not necessarily prohibit those
applications; many states evaluate specific types of water reuse on a case-by-case basis. The
standards in states having the most reuse experience tend to be more stringent than those in states
with fewer reuse projects. States that have water reuse regulations or guidelines typically set
standards for reclaimed water quality and specify minimum treatment requirements, although a few
states, such as Texas and New Mexico, do not prescribe treatment processes and rely solely on
water quality parameters. All water reuse standards are directed principally at public health
protection. For nonpotable reuse applications, water quality requirements generally include limits
for BOD, turbidity or TSS, total or fecal coliform bacteria, nitrogen, and – in some cases – chlorine
contact time and residual.
In the past, most state water reuse criteria were developed in response to a need to regulate a
growing number of water reuse projects in the particular state. Recently, some states that currently
have few reuse projects have taken a pro-active approach and have adopted criteria, which tend to
encourage implementation of projects. Arizona, California, Florida, and Texas, which have had
comprehensive criteria for a number of years, have revised their water reuse regulations within the
last five years to reflect additional reclaimed water uses, advances in wastewater treatment
technology, and increased knowledge in the areas of microbiology and public health protection.
The variations and inconsistencies among state regulations are illustrated in Table 8, which includes
examples of several states’ reclaimed water criteria for fodder crop irrigation, food crop irrigation,
urban irrigation, and toilet flushing.
The State of California has a long history of reuse and developed the first water reuse regulations in
the U.S. in 1918, which have been modified and expanded through the years. California’s water
reuse criteria have served as the basis for reuse standards in other states and countries. The State’s
current Water Recycling Criteria [State of California, 2000] were adopted by the California
Department of Health Services (DHS) in 2000. The regulations include water quality standards,
treatment process requirements, operational requirements, treatment reliability requirements, and
distribution and use area controls. As an example of comprehensive state regulations, the treatment
and quality criteria for nonpotable reuse applications in California are summarized in Table 9.
From a regulatory standpoint, few states have addressed the challenge of developing criteria for
potable reuse, where health risks associated with both pathogenic microorganisms and chemical
constituents need to be taken into account. California and Florida are in the forefront of developing
discrete criteria relating to planned potable reuse of reclaimed water. California has draft criteria for
groundwater recharge, and Florida has adopted criteria for both groundwater recharge and surface
AwwaRF 2006, Used With Permission
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Table 8. Examples of State Water Reuse Criteria for Selected Nonpotable Applications
Fodder Crop Irrigation1
State
Quality Limits
Arizona
4
ƒ 2.2 total
coli/100 mL
ƒ 2 NTU
Not covered
Not covered
Florida
ƒ 200 fecal coli/100
mL
ƒ 20 mg/L CBOD
ƒ 20 mg/l TSS
ƒ Secondary
ƒ Disinfection
New Mexico
(Policy)
ƒ 1,000 fecal
coli/100 mL
ƒ 75 mg/L TSS
ƒ 30 mg/L BOD
Washington
3
ƒ Secondary
Colorado
Texas
2
ƒ No detect. fecal
coli/100 mL
ƒ 2 NTU
Not specified
ƒ 200 fecal coli/100
mL
ƒ 25 mg/L TSS
ƒ 25 mg/L BOD
ƒ 200 fecal coli/100
mL
ƒ 20 mg/L BOD
ƒ 15 mg/L CBOD
ƒ 240 total coli/100
mL
Quality Limits
ƒ Secondary
California
Utah
1
ƒ 1,000 fecal
coli/100 mL
Treatment
Required
Food Crop Irrigation2
ƒ
ƒ
ƒ
ƒ
ƒ
ƒ
ƒ
Not covered
Use prohibited
Treatment
Required
Secondary
Filtration
Disinfection
Secondary
Coagulation4
Filtration
Disinfection
Not covered
Use prohibited
Not specified
Use Prohibited
Use Prohibited
ƒ Secondary
ƒ Disinfection
ƒ No detect. fecal
coli/100 mL
ƒ 2 NTU
ƒ 10 mg/L BOD
ƒ Secondary
ƒ Filtration
ƒ Disinfection
Not specified
Use prohibited
Use prohibited
ƒ Secondary
ƒ Disinfection
ƒ 2.2 total
coli/100 mL
ƒ 2 NTU
ƒ
ƒ
ƒ
ƒ
Secondary
Coagulation
Filtration
Disinfection
Urban Irrigation3
Quality Limits
ƒ No detect. fecal
coli/100 mL
ƒ 2 NTU
ƒ 2.2 total
coli/100 mL
ƒ 2 NTU
ƒ 126 E.coli/100
mL
ƒ 3 NTU
ƒ No detect. fecal
coli/100 mL
ƒ 20 mg/L CBOD
ƒ 5 mg/L TSS
If within 100 ft of
dwelling:
ƒ 5 fecal coli/100
mL
ƒ 10 mg/L BOD
ƒ 3 NTU
ƒ No detect. fecal
coli/100 mL
ƒ 2 NTU
ƒ 10 mg/L BOD
ƒ 20 fecal
coli/100 mL
ƒ 3 NTU
ƒ 5 mg/L BOD
ƒ 2.2 total
coli/100 mL
ƒ 2 NTU
ƒ
ƒ
ƒ
ƒ
ƒ
ƒ
ƒ
ƒ
ƒ
ƒ
Treatment
Required
Secondary
Filtration
Disinfection
Secondary
Coagulation4
Filtration
Disinfection
Secondary
Filtration
Disinfection
ƒ Secondary
ƒ Filtration
ƒ Disinfection
Not specified
ƒ Secondary
ƒ Filtration
ƒ Disinfection
Not specified
ƒ
ƒ
ƒ
ƒ
Secondary
Coagulation
Filtration
Disinfection
Toilet Flushing
Quality Limits
ƒ No detect. fecal
coli/100 mL
ƒ 2 NTU
ƒ 2.2 total
coli/100 mL
ƒ 2 NTU
Not covered
Not covered
ƒ No detect. fecal
coli/100 mL
ƒ 20 mg/L CBOD
ƒ 5 mg/L TSS
ƒ Secondary
ƒ Filtration
ƒ Disinfection
ƒ 100 fecal
coli/100 mL
ƒ 30 mg/L BOD
ƒ 30 mg/L TSS
ƒ No detect. fecal
coli/100 mL
ƒ 2 NTU
ƒ 10 mg/L BOD
ƒ 20 fecal
coli/100 mL
ƒ 3 NTU
ƒ 5 mg/L BOD
ƒ 2.2 total
coli/100 mL
ƒ 2 NTU
More restrictive requirements generally apply where milking animals are allowed to graze on pasture irrigated with reclaimed water.
Food crops eaten raw where there is direct contact between reclaimed water and the edible portion of the crop.
Includes irrigation of parks, playgrounds, schoolyards, residential lawns, and similar unrestricted access areas.
Not needed if filter effluent turbidity does not exceed 2 NTU, the turbidity of the influent to the filters is continually measured, the influent turbidity does not
exceed 5 NTU for more than 15 minutes and never exceeds 10 NTU, and there is capability to automatically activate chemical addition or divert the
wastewater should the filter influent turbidity exceed 5 NTU for more than 15 minutes.
AwwaRF 2006, Used With Permission
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ƒ
ƒ
ƒ
ƒ
ƒ
ƒ
ƒ
Treatment
Required
Secondary
Filtration
Disinfection
Secondary
Coagulation4
Filtration
Disinfection
Not specified
ƒ Secondary
ƒ Filtration
ƒ Disinfection
Not specified
ƒ
ƒ
ƒ
ƒ
Secondary
Coagulation
Filtration
Disinfection
Table 9. California Water Recycling Criteria: Treatment and Quality Criteria for Nonpotable
Uses of Reclaimed Water
Total Coliform
Limitsa
Type of Use
a
b
c
d
e
f
g
h
i
Treatment
Required
Irrigation of fodder, fiber, & seed crops, orchardsb
and vineyards,b processed food crops, nonfoodbearing trees, ornamental nursery stock,c and sod
farms;c flushing sanitary sewers
ƒ None required
ƒ Secondary
Irrigation of pasture for milking animals, landscape
areas,d ornamental nursery stock, and sod farms;
landscape impoundments; industrial or commercial
cooling water where no mist is created;
nonstructural fire fighting; industrial boiler feed;
soil compaction; dust control; cleaning roads,
sidewalks, and outdoor areas
ƒ ≤23/100 mL
ƒ ≤240/100 mL in more than
one sample in any 30-day
ƒ Secondary
ƒ Disinfection
Irrigation of food crops;b restricted recreational
impoundments; and fish hatcheries
ƒ ≤2.2/100 mL
ƒ ≤23/100 mL in more than one
sample in any 30-day period
ƒ Secondary
ƒ Disinfection
Irrigation of food cropse and open access landscape
areas;f toilet and urinal flushing; industrial process
water; decorative fountains; commercial laundries
and car washes; snow-making; structural fire
fighting; and industrial or commercial cooling
where mist is created
ƒ ≤2.2/100 mL
ƒ ≤23/100 mL in more than one
sample in any 30-day period
ƒ 240/100 mL (maximum)
ƒ Secondary
ƒ Coagulationg
ƒ Filtrationh
ƒ Disinfection
Nonrestricted recreational impoundments
ƒ ≤2.2/100 mL
ƒ ≤23/100 mL in more than one
sample in any 30-day period
ƒ 240/100 mL (maximum)
ƒ Secondary
ƒ Coagulation
ƒ Clarificationi
ƒ Filtrationh
ƒ Disinfection
Based on running 7-day median.
No contact between reclaimed water and edible portion of crop.
No irrigation for at least 14 days prior to harvesting, sale, or allowing public access.
Cemeteries, freeway landscaping, restricted access golf courses, and other controlled access areas.
Contact between reclaimed water and edible portion of crop; includes edible root crops.
Parks, playgrounds, schoolyards, residential landscaping, unrestricted access golf courses, and other uncontrolled
access irrigation areas.
Not needed if the filter influent turbidity is continually measured, does not exceed 5 NTU for more than 15
minutes and never exceeds 10 NTU, and there is capability to automatically activate chemical addition or divert
the wastewater.
The turbidity after filtration through filter media cannot exceed an average of 2 NTU within any 24-hour period, 5
NTU more than 5% of the time within a 24-hour period, and 10 NTU at any time. The turbidity after filtration
through a membrane process cannot exceed 0.2 NTU more than 5% of the time within any 24-hour period and 0.5
NTU at any time.
Clarification not required if reclaimed water monitoring requirements for enteric viruses, Giardia, and
Cryptosporidium are met.
Source: Adapted from State of California [2000]
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water augmentation. The most recent draft regulations developed by the California Department of
Health Services are summarized in Table 10. The proposed California regulations address both
surface spreading and injection projects involving potable reuse of the recovered water. The criteria
are intended to apply only to planned groundwater recharge projects using recycled water (i.e.,
any water reclamation project designed, constructed, or operated for the purpose of recharging a
groundwater basin designated for use as a domestic drinking water source). They do not apply to
wastewater disposal projects. Florida’s regulations pertaining to potable reuse are summarized in
Table 11. Some of the other states rely on EPA’s Underground Injection Control regulations to
protect potable groundwater basins, while some states prohibit potable reuse altogether.
The U.S. EPA published revised Guidelines for Water Reuse [U.S. Environmental Protection
Agency, 2004] in 2004. The primary purpose of the document is to provide guidelines, with
supporting information, for utilities and regulatory agencies in the U.S., particularly in states
where standards do not exist or are being revised. The guidelines address various aspects of
water reuse and include recommended treatment processes, reclaimed water quality limits,
monitoring frequencies, setback distances, and other controls for various water reuse
applications. Table 12 summarizes the treatment processes and reclaimed water quality limits
recommended in the guidelines for various reclaimed water applications.
3.1.3 Public Perception/Acceptance
Surveys over the last three decades have consistently indicated a large measure of public support
for water reuse programs. General opinion studies conducted in the 1970s and 1980s indicated
that about one-half of the respondents were opposed to potable reuse (ranged from 46-67%), 1525% were opposed to swimming in reclaimed water, 7-21% were opposed to irrigating
vegetables with reclaimed water, and 6% or less were opposed to residential lawn irrigation and
irrigation of parks [Bruvold, 1972; Stone and Kahle, 1974, Kasperson et al., 1974; Olsen et al.,
1979; Bruvold, 1981; Milliken and Lohman, 1983; Lohman and Milliken, 1985]. Some more
recent studies [Bruvold, 1991; Rea & Parker Research, 2004] produced similar results for
potable reuse, while opposition to the use of reclaimed water for the irrigation of parks,
playgrounds, and schoolyards increased slightly from earlier surveys and ranged from 9% to
25% [OmniTrak Group Inc., 2001; Fairbank, Maslin, Maullin & Associates, 2004; Rea & Parker
Research, 2004].
In one survey by Bruvold and Crook [1980] of communities where water reuse was being
considered at the time of the survey, respondents’ issues of concern were ordered as follows:
(1)
(2)
(3)
(4)
(5)
Ability of the project to conserve water;
Environmental enhancements achieved by the project;
Protection of public health;
Treatment costs; and
Distribution costs.
The more statistically-oriented surveys reviewed included questions related to attitudes, beliefs,
education level, etc. Information gleaned from those studies indicates that some general
correlations exist between attitude, beliefs, and demographics. Comparing characteristics of
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Table 10. California Proposed Requirements for Groundwater Recharge with Recycled
Water
Type of Recharge
Contaminant Type
Surface Spreading
Subsurface Injection
Pathogenic Microorganisms
Filtration
≤ 2 NTU
Disinfection
5-log virus inactivation, a ≤ 2.2 total coliform per 100 mL
Retention Time
Undergroundb
6 months
12 months
Horizontal Separation
150 meters (500 feet)
600 meters (2000 feet)
Regulated Contaminants
Drinking Water
Standards
Meet all drinking water MCLs (except nitrogen) and new federal and state
regulations as they are adopted
ƒ 5 mg/L total N in or above mound (blending allowed), or
ƒ 10 mg/L Total N with DO in excess of BOD (blending allowed), or
ƒ NO2 and NO3 MCLs in groundwater downgradient of recharge area
Nitrogen
Unregulated Contaminants
TOC in Filtered
Wastewater
TOC ≤ 16 mg/L c in any portion of the filtered wastewater not subjected to
RO treatment
RO treatment as needed to achieve:
100% RO treatment to achieve:
TOC in Recycled
Water
ƒ TOC level specified by DHS for
existing project with no RWC
increase
ƒ TOC ≤
0.5 mg/L
(new project or
RWC
increased RWC at existing project)
ƒ Compliance point is in recycled
water or moundd (no blending)
Recycled Water
Contribution (RWC)
a
b
c
d
ƒ TOC level specified by DHS for
existing project with no RWC
increase
ƒ TOC ≤
0.5 mg/L
(new project or
RWC
increased RWC at existing
project)
≤ 50 % subject to above requirements
50-100 % subject to additional requirements
The virus log reduction requirement may be met by a combination of removal and inactivation.
May be reduced to as little as 60 m (200 ft) upon demonstration via tracer testing that the required detention time
will be met at the proposed alternative distance.
The TOC limit is intended to restrict recharge projects to effluents with the same TOC as those studied and used
as a basis for these criteria. The TOC is not intended as a performance standard for filtration.
If mound monitoring approved
Source: Adapted from California Department of Health Services [2004]
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Table 11. Florida Regulations Relating to Potable Reuse
Type of Use
Rapid infiltration basins in
unfavorable geohydrologic
conditions
Injection to groundwater
Injection to formations of Floridan or
Biscayne Aquifers having TDS
<500 mg/L
Discharge to Class I surface waters
(used for potable supply)
a
b
Water Quality Limits
No detectable fecal coli/100 mLa
5.0 mg/L TSS
Primary & secondary drinking water
standards
a
ƒ No detectable fecal coli/100 mL
ƒ 5.0 mg/L TSS
ƒ Primary & secondary drinking water
standards
a
ƒ No detectable fecal coli/100 mL
ƒ 5.0 mg/L TSS
ƒ 3 mg/L TOC
b
ƒ 0.2 mg/L TOX
ƒ Primary & secondary drinking water
standards
a
ƒ No detectable fecal coli/100 mL
ƒ 5 mg/L TSS
ƒ 20 mg/L CBOD
ƒ 10 mg/L NO3 (as N)
ƒ Primary & secondary drinking water
standards
ƒ
ƒ
ƒ
Treatment Required
ƒ
ƒ
ƒ
Secondary
Filtration
Disinfection
ƒ
ƒ
ƒ
Secondary
Filtration
Disinfection
ƒ
ƒ
ƒ
ƒ
Secondary
Filtration
Disinfection
Activated carbon adsorption
ƒ
ƒ
ƒ
Secondary
Filtration
Disinfection
No detectable fecal coliform organisms/100 mL in at least 75 percent of the samples, with no single sample to
exceed 25 fecal coliform organisms/100 mL.
TOX = total organic halogen.
Source: Adapted from Florida Department of Environmental Protection [1999]
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Table 12. U.S. EPA Guidelines for Water Reuse
Type of Use
a
b
c
d
e
Reclaimed Water Quality
Treatment
Urban uses, crops eaten raw,
recreational impoundments
ƒ pH = 6 – 9
ƒ ≤10 mg/L BOD
ƒ ≤2 NTUa
ƒ No detectable fecal coli/100 mLb
ƒ ≥1 mg/L Cl2 residualc
ƒ Secondary
ƒ Filtration
ƒ Disinfection
Restricted access area irrigation,
processed food crops, nonfood
crops, aesthetic impoundments,
construction uses, industrial
cooling,d environmental reuse
ƒ pH = 6 – 9
ƒ ≤30 mg/L BOD
ƒ ≤30 mg/L TSS
ƒ ≤200 fecal coli/100 mLe
ƒ ≥1 mg/L Cl2 residualc
ƒ Secondary
ƒ Disinfection
Groundwater recharge of
nonpotable aquifers by spreading
ƒ Site specific and use dependent
ƒ Site specific and use
dependent
ƒ Primary (minimum)
Groundwater recharge of
nonpotable aquifers by injection
ƒ Site specific and use dependent
ƒ Site specific and use
dependent
ƒ Secondary(minimum)
Groundwater recharge of potable
aquifers by spreading
ƒ Site specific
ƒ Meet drinking water standards after
percolation through vadose zone
ƒ Secondary
ƒ Disinfection
ƒ May also need filtration
& advanced wastewater
treatment
Groundwater recharge of potable
aquifers by injection, augmentation
of surface supplies
Includes the following:
ƒ pH = 6.5 – 8.5
ƒ ≤2 NTUa
ƒ No detectable fecal coli/100 mLb
ƒ ≥1 mg/L Cl2 residualc
ƒ ≤3 mg/L TOC
ƒ ≤0.2 mg/L TOX
ƒ Meet drinking water standards
ƒ Secondary
ƒ Filtration
ƒ Disinfection
ƒ Advanced wastewater
treatment
Should be met prior to disinfection. Average based on a 24-hour time period. Turbidity should not exceed 5 NTU
at any time.
Based on 7-day median value. Should not exceed 14 fecal coli/100 mL in any sample.
After a minimum contact time of 30 minutes.
Recirculating cooling towers.
Based on 7-day median value. Should not exceed 800 fecal coli/100 mL in any sample.
Source: Adapted from U.S. Environmental Protection Agency [2004]
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individuals who responded favorably to water reuse to individuals who responded negatively
indicate that public acceptance appears to be higher for younger respondents and those with
higher education, income, and occupational levels. While some surveys indicated that men are
more likely to favor water reuse than women, the data are not conclusive. Hartley [2003]
synthesized data from several public perception studies and concluded that positive responses to
reclaimed water use generally are higher when:
•
•
•
•
•
•
•
•
•
•
The degree of human contact is minimal;
Protection of public health is clear;
Protection of the environment is a benefit of reuse;
Promotion of water conservation is a benefit of reuse;
The cost of treatment and distribution technologies and systems is reasonable;
Perception of wastewater as the source of reclaimed water is minimal;
The community has high awareness of water supply problems;
The role of reclaimed water in the overall water supply is clear;
The perception of the reclaimed water quality is high; and
Confidence in local management of public utilities and technologies is high.
While surveys generally reflect prevailing views of water reuse, it is not uncommon for small
numbers of individuals to oppose or question the acceptability of projects and disrupt or delay
implementation of those projects. The stated reasons almost always pertain to protection of
public health. Concurrence from regulatory agencies – particularly health officials – that the use
of reclaimed water is safe usually suffices to satisfy all but the most fervent opponents. Stronger
opposition is presented when concerned individuals band together to form organized oppositionbased committees or groups. Health concerns were among the reasons given for the recent
failure of three planned indirect potable reuse projects in California (San Diego, Los Angeles,
and the Dublin San Ramon Services District in the San Francisco Bay Area) and one in Florida
(Tampa Bay area) to garner public and/or political support. Some nonpotable reuse projects
have been delayed or modified due to opposition by organized groups [Harris, 1998; Ingram et
al., 2004].
Many communities have extensive outreach programs to inform and educate the public. They
include school curricula on the subject of water reuse, informational brochures, public forums or
other community meetings, telephone hotlines to answer any questions regarding water reuse,
websites, videos, radio and television programs, organized visits to water reclamation facilities,
and sponsored events with themes relating to water reuse. These efforts have proven to be
effective in educating the public and diffusing or preventing opposition in several communities.
3.2 Canada
Canada is a water-rich country with few projects reusing municipal wastewater, although
industry uses about 75% of all water used in Canada, and 35% of this amount is recycled. There
are areas receiving limited rainfall where water reuse projects have been implemented. Current
uses include agricultural irrigation, golf course irrigation, and some other small scale landscape
irrigation. Greywater is used for toilet flushing in a few buildings, although statistics are lacking.
Interest is growing, due to steadily increasing water demands, climate changes, opportunities to
save on future expansion of the water supply infrastructure, need to reduce or eliminate
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wastewater discharges to sensitive receiving waters, and opportunities to provide inexpensive
water services in isolated locations [Canadian Council of Ministers of the Environment, 2002].
There are no federal regulations addressing water reuse in Canada, and only two provinces
(Alberta and British Columbia) have developed regulations. The regulations that have been
adopted in British Columbia provide criteria for nonpotable uses of reclaimed water and include
treatment and water quality requirements similar to those in U.S. states such as California and
Florida [British Columbia Ministry of Environment, Lands, and Parks, 1999]. Regulations in
Alberta are considerably less restrictive, requiring – among other criteria – a minimum of
secondary treatment, <100 mg/L TSS, <1,000 total coli/100 mL, and <200 fecal coli/100 mL for
both unrestricted and restricted urban and agricultural irrigation [Alberta Environment, 2000].
Participants at a recent workshop in Canada considered the most significant concerns to be
related to health issues and identified the following research needs:
•
•
•
•
•
•
•
•
•
Identification of emerging health issues regarding endocrine disruptors, pharmaceutically
active compounds, organic compounds, salts, and heavy metals;
Long-term environmental impacts of reclaimed water use;
Evaluation of the fate of microbial and chemical contaminants and determination of
appropriate surrogates;
Assessment of the effect of storage on reclaimed water quality;
Effect of reclaimed water irrigation practices on crops, turf grass, and soil;
Development of risk assessment and management methods for water reuse applications;
Development of multiple barriers for the control of microbial and chemical contaminants;
Better economic analysis to assess water reuse alternatives more effectively; and
Improved collaboration and communication among researchers in the water reuse arena
[Canadian Council of Ministers of the Environment, 2002].
3.3 Latin America (Central and South America)
More than 80% of the 700 million people in Latin America live in urban areas, making large
quantities of treated and untreated wastewater available for reuse, principally for agricultural
irrigation. Drivers for water reuse include wastewater availability, seasonal variations in water
availability and use, low or no cost of wastewater to farmers, high salinity of many natural
waters, and soil and crop benefits associated with organic matter and nutrients in wastewater
used for irrigation. Water availability varies dramatically throughout the region, with countries
in Central America generally having larger volumes of natural water resources than some
countries in South America such as Peru and Chile.
While there are many projects using treated effluent for reuse, the use of untreated wastewater is
widespread throughout the region. Less than 14% of the wastewater in Latin America receives
any treatment prior to discharge, and only 6% receives acceptable treatment [Cavallini and
Young, 2002]. More than 500,000 ha (1.2 x 106 ac) of agricultural land is irrigated with
untreated wastewater, not including land irrigated with surface water contaminated with sewage.
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Argentina: Agricultural irrigation using untreated wastewater has been occurring in western
regions of the country since the beginning of the 20th Century. Argentina requires compliance
with the WHO guidelines for irrigation, although untreated or minimally treated wastewater is
being used in some areas. The largest project is in Mendoza, where more than 160,000 m3/d (42
mgd) of reclaimed water treated in lagoons is used to irrigate forest land and several types of
crops [Kotlik, 1998].
Brazil: Use of reclaimed water is low due to abundant water resources and lack of wastewater
collection systems in many parts of the country. Unplanned reuse is common, however, as
heavily polluted river water is diverted for agricultural irrigation, including vegetable crops. The
low availability of water in Sao Paulo has resulted in research and planning efforts to use
reclaimed water for industrial and irrigation purposes. A project is being developed to deliver
2,730 m3/d (0.45 mgd) of reclaimed water to the Sao Paulo Airport for a variety of uses,
including toilet and urinal flushing, air conditioner chiller water, airplane washing, and irrigation
[U.S. Environmental Protection Agency, 2004]. A second phase of the project may include
groundwater recharge in the vicinity of the airport.
Chile: Most of the cities have little or no wastewater treatment and discharge wastewater into
canals or rivers where water is subsequently withdrawn for agricultural irrigation. In Santiago,
for example, as much as 80% of the city’s raw wastewater is collected, discharged into a canal
system, from which it is distributed for irrigation of several food crops. This has resulted in
higher disease rates in the Santiago area, and steps have been taken to provide treatment for all of
the water in as many as 16 treatment plants. The largest facility in operation provides secondary
treatment and has a capacity of 380,000 m3/d (100 mgd) [U.S. Environmental Protection
Agency, 2004].
Mexico : Geographical distribution of water resources and irrigation areas result in water
scarcity in the northern regions of the country which have only about 20% of the country’s water
resources but account for 90% of the irrigation and 70% of the industry. Agricultural use of
wastewater for irrigation is widespread in Mexico; almost 350,000 ha (860,000 ac) are irrigated
with wastewater, generally with little or no treatment. Untreated wastewater from Mexico City
is used for some urban uses in the Mexico City area, such as recreational lakes and landscape
irrigation, although most of the wastewater is used for agricultural irrigation of all types of food
crops, including vegetable and salad crops, on more than 85,000 ha (210,000 ac) in the
Mezquital Valley [Jimenez et al., 2001]. Most of the wastewater is stored for several months in
reservoirs prior to use, thus improving its quality, although the water typically contains 10,000
fecal coli/100 mL when used for irrigation. This practice has resulted in illnesses to farm
workers and consumers of the crops [Blumenthal et al., 2000]. Based on research studies,
authorities in Mexico have concluded that advanced primary treatment followed by sand
filtration and chlorine disinfection produces reclaimed water that meets the standards in Table 13
[Jimenez and Chavez, 2000]. The use of reclaimed water by industry is growing in Mexico. In
metropolitan Monterrey, for example, reclaimed water is used for cooling by 15 industries. The
reclaimed water costs less than one-half that of groundwater and about one-fifth that of potable
water [U.S. Environmental Protection Agency, 2004].
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Table 13. Mexico Standards for Agricultural Reuse
Type of Irrigation
Fecal coli/100 mL
(MPN)
Helminth Ova
(No./L)
Restricted (excludes salad and
vegetable crops eaten raw)
1,000 (monthly mean)
2,000 (daily mean)
≤5
Unrestricted (all crops)
1,000 (monthly mean)
2,000 (daily mean)
≤1
Source: Adapted from Blumenthal et al. [2000]
Peru: A very low percentage of municipal wastewater in Peru is treated, and the use of
untreated wastewater to irrigate all types of food crops, including food crops eaten raw, is
prevalent throughout the country. Where treatment does exist, it is typically done via
inadequately designed and operated stabilization ponds or lagoons. While it is likely that this
results in significant infectious disease in the country, the many other possible disease
transmission routes preclude attributing the spread of disease to the irrigation practices [Strauss
and Blumenthal, 1988].
3.4 Europe
Europe has experienced growing water stress in the last two decades in terms of both water
scarcity and water quality degradation, and about half of the countries have water stress issues at
the present time [Bixio et al., 2005, ]. A water stress index (i.e., the ratio of a country’s total
water withdrawal to its total renewable freshwater resources) of 20 or greater indicates that water
management is needed to balance supply and demand. Water stress is particularly significant in
highly urbanized areas and some coastal areas and could increase due to population increases,
changing weather patterns, tourist activities, etc. Countries exhibiting high water stress include
Cyprus, Malta, Belgium, Spain, Germany, and Italy [Hochstrat et al., 2005]. Countries in
Northern Europe generally have low water stress, although some regions currently use almost
100% of their available water resources [Angelakis et al., 2005].
Although water reuse has been practiced for more than a century in Europe, particularly for
agricultural irrigation using relatively low quality water, the practice – with some exceptions –
has been slow to develop in most areas despite a 1991 EU directive that “treated wastewater shall
be reused whenever appropriate” [EU, 1991]. The directive is somewhat vague, and the
European Union of National Associations of Water Suppliers and Waste Water Services
(EUREAU) is urging a clarification of the directive to encourage water reuse in Europe
[EUREAU, 2004]. A more recent legislative action, the Water Framework Directive, is leveled
at river basin management but will indirectly affect water reuse. The purpose of the objective is
to establish a framework for the protection of inland surface waters and groundwater [EC, 2000].
3.4.1 Applications
There are more than 200 existing water reuse projects in Europe, and many more are in various
stages of planning [Bixio et al., 2005]. It has been estimated that about 670 Mm3 (180 billion
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gallons) of reclaimed water was used in Europe in 2003, accounting for slightly more than 2% of
the treated effluent produced. One mathematical model predicts that the amount of reclaimed
water used in Europe will increase to 3,450 Mm3/yr (900 billion gallons/yr) by the year 2025
[Aquarec, 2003]. In Southern Europe, about 80% of the reclaimed water produced is used for
either agricultural irrigation (44%) or urban or environmental applications (37%), while in
Northern Europe urban and environmental applications account for about 50% of the reclaimed
water used and industrial uses account for about 33% of the projects [Bixio et al., 2005].
Information developed as part of Aquarec, a research project funded by the European Union
(EU), indicates that there are hundreds of water reuse projects in Europe. The volume of
reclaimed water used in the EU is increasing at a rate of about 25% per year [EUREAU, 2004].
Uses range from pasture irrigation to potable reuse. Although many cities rely on indirect
potable reuse via wastewater discharges to rivers and subsequent abstraction downstream or
extraction of groundwater containing treated wastewater, it is often done by default and not as
the result of planned integrated water resources management. Examples of water reuse in
Europe are summarized below.
•
•
•
•
•
•
In the UK, indirect potable reuse via discharges to rivers and subsequent water
withdrawals downstream occurs in many parts of the country but mainly in the major
rivers in the eastern and southern regions of the country. There are about 350 wastewater
treatment plants that discharge into the River Thames, and indirect potable reuse
downstream accounts for about 12% of the available water resources in an average year.
In the lower parts of the basin, that figure can rise to 70% in a dry year [Planet Water,
2003]. In 1997, an indirect potable reuse scheme was implemented in Essex in Southeast
England, where up to 40,000 m3/d (11 mgd) of treated effluent is used to augment flow in
the River Chelmer, from which water is withdrawn to a raw water reservoir for subsequent
treatment and potable use [Lazarova et al., 2001; Durham, 2005]. A greywater system was
developed for the Millennium Dome in Greenwich, and there is increasing interest and
research directed at the treatment and reuse of greywater in the UK.
In Wulpen, Belgium, 2.5 Mm2/yr (660 million gallons/yr) of urban wastewater is treated
by MF and RO stored for 1-2 months in the aquifer, and used for water supply
augmentation [Angelakis et al., 2005].
Berlin, Germany, recharges treated surface water that contains up to 50% wastewater to
augment potable groundwater supplies. Reclaimed water is also used for wetlands
enhancement. Potable reuse utilizing riverbank filtration is practiced in Germany in the
Rhine Valley and elsewhere.
There are several projects in the Netherlands where reclaimed water typically receiving
treatment via constructed wetlands is used for industrial purposes, recreational purposes,
and environmental enhancement [Aquarec, 2004].
There are at least 30 water reuse projects in France, half of which use reclaimed water for
agricultural irrigation; the other 15 projects use reclaimed water for golf course and urban
area irrigation [Angelakis et al., 2005]. One of the largest projects is in Clermont-Ferrand,
where 10,000 m3/d (2.6 mgd) of tertiary treated reclaimed water is used to irrigate 700 ha
(1,700 ac) of maize.
Spain is one of the leading countries in Europe to implement water reuse projects, where
more than 100 projects use reclaimed water for a variety of applications, including
AwwaRF 2006, Used With Permission
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•
•
agricultural irrigation, landscape irrigation, groundwater recharge to prevent seawater
intrusion, and river flow augmentation [Angelakis et al., 2005; Lazarova et al., 2001]. The
Concorsi da la Costa Brava has been a leader in implementing water reuse in Spain, where
tertiary treated reclaimed water is used for a variety of landscape irrigation uses and other
urban applications. Reclaimed water is used for environmental enhancement of lagoons in
Valencia and Costa Brava, Spain.
The Intermunicipal Water Company of the Veurne region has been using reclaimed water
for groundwater recharge to an unconfined dune aquifer since 2002 at Torreele, Belgium.
Treatment includes microfiltration to meet quality requirements. The recharged water is
recaptured after a minimum residence time of 40 days in the dune aquifer.
Although water withdrawals in Sweden represent a small fraction of its renewal water
resources, there are several irrigation projects in the water-scarce southeast region of the
country using untreated reclaimed water after storage of about nine months in reservoirs
[U.S. Environmental Protection Agency, 2004].
As indicated in Figure 4, Spain and Italy reuse considerably more wastewater than other
countries on a volume basis, although Cyprus and Malta reuse almost all of the wastewater they
produce, mainly for irrigation.
3.4.2 Technology
In most European countries, all wastewater discharges to fresh waters require a minimum of
secondary treatment; nutrient removal is required in sensitive areas. Thus, many water reuse
projects use secondary effluent for applications where it is acceptable, such as landscape
irrigation, agricultural irrigation, and industrial cooling. Tertiary treatment (i.e., secondary
treatment followed by filtration -- with or without chemical pre-treatment -- and disinfection) is
most common in the Mediterranean region, while constructed wetlands are found in the
Netherlands and Belgium [Bixio et al., 2005]. MBR treatment has been used successfully to
produce high quality reclaimed water and is increasing in usage. For example, in France alone
there are more than 10 MBR projects where industrial wastewater is treated for reuse [Angelakis
et al., 2005]. Advanced wastewater treatment including membranes, typically MF or UF
preceding RO, is used in some recharge projects and at least one indirect potable reuse project.
Disinfection is accomplished almost exclusively either by chlorine or UV, with a current trend
toward UV. Several research projects and demonstration studies are underway that are funded
by the EU addressing treatment technologies, water quality, and integrated water management.
These studies are diverse and include research directed at pharmaceuticals and personal care
products in reclaimed water used for potable purposes, cost-effective technologies for
agricultural reuse, MBR treatment, sustainable water management, and desalination of
groundwater.
3.4.3 Common Issues
Bixio et al. [2005] listed several issues common to many water reuse projects in Europe. They
are as follows:
•
Lack of integrated water management;
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Figure 4. Water Reuse in Europe
10000
100
treated wastewater
reused wastewater
share of treated wastewater reused
Cyprus
Israel
Malta
Spain
Italy
Greece
0
Germany
1
Netherlands
25
Belgium
10
Poland
50
France
100
%
75
Austria
Mm³/a
1000
sources: Eurostat; National Statistics; scientific publications
Source: Excerpted from: EUREAU [2004]
•
•
•
•
Need to strengthen cooperation among stakeholders;
Establishment of water reuse criteria/guidelines;
Economic/financing constraints; and
Public acceptance.
Financing has been identified as one of the major barriers to water reuse in Europe. Some
governments or regulatory agencies provide grants up to 50% of the capital costs of a project,
with the remaining costs borne by the water reuse project. Subsidies are not available for
operation and maintenance costs. Factors such as developing new sources of potable supply and
environmental benefits associated with reuse versus surface water discharge are not usually
considered during an economic analysis. There have been some financial incentives in specific
regions. For example, in Costa Brava, Spain, a regulation was adopted that exempted the user
tax for reclaimed water [Mujeriego, et al., 2000].
3.4.4 Regulations
There currently are no standardized water reuse standards for the entire European community,
and water reuse criteria and guidelines differ from country to country in those countries that have
developed standards or guidelines. Different approaches and philosophies have resulted in
widely differing regulations. Some countries (or regions of countries) have imposed restrictive
standards similar to those in Australia and the U.S., while others base their standards on the
WHO guidelines for wastewater use in agriculture and aquaculture [World Health Organization,
1989]. In an effort to develop a rationale for setting standards for water reuse, a project jointly
funded by the WateReuse Foundation, Awwa Research Foundation, and UKWIR developed a
AwwaRF 2006, Used With Permission
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“Framework for Developing Water Reuse Criteria with Reference to Drinking Water Supplies”
[UKWIR, 2005]. Existing water reuse criteria/guidelines within the EU are summarized in Table
14 [Aquarec, 2003]. Suggested guidelines for water reuse in the Mediterranean Region
developed by Bahri and Brissaud [2002] are provided in Table 15.
3.5 Middle East and North Africa
The drivers for water reuse in developing countries in the Middle East vary but are principally
related to population growth, climate, limited water resources, and socio-economic conditions.
The annual reclaimed water use for several countries in the region is provided in Table 16.
Agricultural irrigation is the leading use of reclaimed water in the Middle East. Unplanned reuse
is common, where untreated or minimally-treated wastewater is discharged into watercourses
and subsequently withdrawn by farmers with or without mixing with water that may be present
in the rivers. Farmers are often unaware that the irrigation water they draw to irrigate food crops
is grossly contaminated; the link between high disease incidence and wastewater is seldom
recognized. In some countries, untreated or partially treated wastewater is preferred over more
highly treated wastewater for irrigation due to its low (or no) cost and high organic and nutrient
value. In some Muslim countries, the use of wastewater for irrigation has been opposed on
religious grounds (i.e., that the water originated from wastewater and is therefore contaminated).
This resistance has been relieved in some cases by religious scholars who have issued fatwas
(i.e., legal pronouncements issued by religious specialists on specific issues, usually at the
request of an individual or judge to settle questions where Islamic jurisprudence is unclear)
stating that wastewater reclamation and reuse can result in a “pure” water source of water that is
safe and adequate for different applications [Jiménez and Asano, 2004].
Many developing countries in the Middle East consider water reuse criteria in industrialized
countries to be overly restrictive and too expensive to implement. WHO has developed
guidelines that are low cost, easy to operate, and have minimal water quality requirements and,
thus, are embraced by many countries in the region. Some countries – particularly in the Gulf
region – that have the financial resources and technical expertise to construct and operate
sophisticated water reclamation facilities have opted to implement water reuse projects similar in
scope and complexity to those in Australia and the U.S. The WHO guidelines are summarized in
Table 17. The 1989 WHO guidelines are currently under revision [Carr et al., 2004] and take
into account epidemiological and risk assessment information [Blumenthal et al., 2000].
The WHO guidelines recognize that there are limited health effects data for reclaimed water used
for aquaculture and do not recommend definitive bacteriological quality standards for this use.
However, tentative coliform guidelines in the guidelines recommend a geometric mean of 1,000
fecal coliforms/100 mL, which is intended to insure that invasion of fish muscle is prevented. The
same fecal coliform standard is recommended for pond water in which aquatic vegetables
(macrophytes) are grown. Since pathogens may accumulate in the digestive tract and
intraperitoneal fluid of fish and pose a risk through cross-contamination of fish flesh or other edible
parts - and subsequently to consumers if hygiene standards in fish preparation are inadequate - a
recommended public health measure is to ensure maintenance of high standards of hygiene during
fish handling and gutting. A total absence of viable trematode eggs, which is achievable by
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Table 14. Examples of European Water Reuse Regulations and Guidelines
Reuse criteria for:
Country or
Region
AGR URB GWR IND
WHO
X
Spain
X
Balearic Islands
Italy
Parameter
X
X
TC
CFU/100 ml
FC
CFU/100 ml
Not set
1000
0
200
1000
10000
1000
X
X
2
20
3000
2
10
2
20
X
Sicily
X
Puglia
X
Emilia-Romagna
X
France
X
X
Cyprus
X
X
Greece
X
X
Greece
X
X
Austria
X
X
UK
X
X
X
Germany (Berlin)
X
X
X
X
X
100
supranational
<1
National proposal
Regional
Not set
National
1000
1/L
Regional
2
0/L
Regional
Not set
1000
n.s.r.
n.s.r.
50
200
1000
3000
10
100
1000
10000
5
5
5
200
Not detected
2000
n.s.r.
Not detected
X
Level of
Regulation
Helminth
eggs
No./L
1
Regional
1/L
1/L
n.s.r.
National
0/L
National
0.1/L
1/L
1/L
1/L
National proposal
National proposal
Restriction of crop and exposure
Domestic uses
Urban use with public contact
Restricted irrigation, fodder crops, aquaculture
Irrigation of areas with restricted access, industry
Unrestricted irrigation
Recirculated cooling systems
Nonpotable aquifers
Restricted irrigation
Restriction of crop and exposure
National proposal
Unrestricted irrigation, toilet flushing, clothes washing, air conditioners
Irrigation and groundwater recharge are authorized in conformance with
Water Law, Ordinance on manure use
Local
TC – total coliforms
FC – fecal coliforms
n.s.r. – no standard recommended
Source: Adapted from Aquarec, 2003
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Restriction of crop and exposure
Domestic uses, GWR by injection
Urban uses, unrestricted irrigation
GWR, pastures
Fodder & fiber crops, industrial cooling
Unrestricted irrigation
Unrestricted irrigation
Restricted irrigation
Unrestricted irrigation
Unrestricted irrigation
Restricted irrigation
Unrestricted irrigation
Restricted irrigation
A - unrestricted irrigation (crops, public greens)
B – cereals, orchards; accessed by workers
C – cereals, industrial crops, orchards
National proposal
10/mL
AGR – agricultural irrigation
URB – municipal uses, landscape irrigation, domestic uses
GWR – groundwater recharge
IND – industrial uses
Recommended Uses
30
Table 15. Recommended guidelines for water reuse in the Mediterranean Region
Quality criteria
Microbiological
Water category
Intestinal
FC(b) or E. coli
nematode(a)
(cfu/100 mL)
(# Eggs/liter)
Category I
a) Residential reuse: private garden watering,
toilet flushing, vehicle washing.
b) Urban reuse: irrigation of areas with free
admittance (greenbelts, parks, golf courses,
sport fields), street cleaning, firefighting,
≤ 200 (d)
fountains, and other recreational places.
≤ 0.1(g)
c) Landscape and recreational impoundments:
ponds, water bodies and streams for
recreational purposes, where incidental
contact is allowed (except for bathing
purposes).
Category II
a) Irrigation of vegetables (surface or sprinkler
irrigated), green fodder and pasture for direct
grazing, sprinkler-irrigated fruit trees
≤ 1000 (d)
b) Landscape impoundments: ponds, water
≤ 0.1(g)
bodies and ornamental streams, where public
contact with water is not allowed.
c) Industrial reuse (except for food industry).
Category III
Irrigation of cereals and oleaginous seeds,
fiber, & seed crops, dry fodder, green fodder
without direct grazing, crops for canning
None required
industry, industrial crops, fruit trees (except
≤1
sprinkler-irrigated)(e), plant nurseries,
ornamental nurseries, wooden areas, green
areas with no access to the public.
Category IV
a) Irrigation of vegetables (except root crops)
with surface and subsurface trickle systems
(except micro-sprinklers) using practices
(such as plastic mulching, support, etc.)
guaranteeing absence of contact between
reclaimed water and edible part of vegetables.
b) Irrigation of crops in category III with
None required None required
trickle irrigation systems (such as drip,
bubbler, micro-sprinkler and subsurface).
c) Irrigation with surface trickle irrigation
systems of green areas with no public access.
d) Irrigation of parks, golf courses, sport fields
with subsurface irrigation systems.
(a)
(b)
(c)
(d)
(e)
(f)
(g)
Physicalchemical
(c)
SS
(mg/L)
Wastewater treatment
expected to meet the criteria
≤ 10
Secondary treatment + filtration
+ disinfection
≤ 20
≤ 150 (f)
Secondary treatment or
equivalent + filtration +
disinfection, or Secondary
treatment or equivalent + either
storage or well-designed series
of maturation ponds or
infiltration percolation
≤ 35
≤ 150 (f)
Secondary treatment or
equivalent + a few days storage,
or Oxidation pond systems
Pretreatment as required by the irrigation
technology, but not less than primary
sedimentation
Ascaris and Trichuris species and hookworms; limit is also intended to protect against risks from parasitic protozoa.
FC: faecal coliforms.
SS: Suspended solids.
Values must be confirmed at the 80% of the samples per month, minimum number of samples 5.
In the case of fruit trees, irrigation should stop two weeks before fruit is picked, and no fruit should be picked off the ground.
Sprinkler irrigation should not be used.
Stabilization ponds.
As very few investigations, if any, have been carried out on how to reach < 0.1 nematode egg /L, this criterion is considered a
medium term objective and is provisionally replaced by <1 nematode egg /L.
Source: Adapted from Bahri and Brissaud, 2002
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Table 16. Water Reuse in the Middle East
Country
Bahrain
Egypt
Iran
Israel
Jordan
Kuwait
Lebanon
Libya
Morocco
Oman
Qatar
Saudi Arabia
Syria
Tunisia
Turkey
U.A. Emirates
Yemen
Year
1991
2000
1999
1995
1997
1997
1997
1999
1994
1995
1994
2000
2000
1998
2000
1999
2000
Annual Reclaimed Water Usage
% of Total
Billion
3
Water
Mm
Gallons
Withdrawn
15
3.96
6
700
185
1
154
40.7
0.2
200
52.8
10
58
15.3
6
80
21.1
15
2
0.53
0.2
40
10.6
1
38
10.0
0.3
26
6.87
2
25
6.60
9
217
57.3
1
370
97.7
3
28
7.40
1
50
13.2
0
185
48.9
9
6
1.59
0
Source: Adapted from U.S. Environmental Protection Agency [2004]
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Table 17. World Health Organization Recommended Microbiological Guidelines for Wastewater Use in Agriculturea
Category
Reuse
Conditions
Exposed
Group
A
Irrigation of crops likely
to be eaten uncooked,
sports fields, public
parksd
Workers,
consumers,
public
B
Irrigation of cereal
crops, industrial crops,
fodder crops, pasture
and treese
C
Localized irrigation of
crops in Category B if
exposure of workers and
the public does not
occur
Workers
None
Fecal coliforms
(geometric mean
no. per 100 mL)c
Wastewater treatment
expected to achieve the
required microbiological
quality
≤1
≤1,000
A series of stabilization ponds
designed to achieve the
microbiological quality
indicated, or equivalent
treatment
≤1
No standards
recommended
Retention in stabilization
ponds for 8-10 days or
equivalent helminth and fecal
coliform removal
Not applicable
Pretreatment as required by
the irrigation technology, but
not less than primary
sedimentation
Intestinal nematodesb,
(arithmetic mean no. of
eggs per liter)c
Not applicable
a
In specific cases, local epidemiological, sociocultural, and environmental factors should be taken into account, and the guidelines modified accordingly.
Ascaris and Trichuris species and hookworms.
c
During the irrigation period.
d
A more stringent guideline (200 fecal coliforms per 100 mL) is appropriate for public lawns, such as hotel lawns, with which the public may come into direct
contact.
e
In the case of fruit trees, irrigation should cease 2 weeks before fruit is picked, and no fruit should be picked off the ground. Sprinkler irrigation should
not be used.
b
Source: World Health Organization, 1989
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properly-designed and operated stabilization pond systems, is recommended as the appropriate
helminth quality guideline for aquaculture use of reclaimed water.
The 1989 WHO guidelines identify waste stabilization ponds as the method of choice in meeting
these guidelines in warm climates where land is available at reasonable cost. Based on helminth
removal, the guidelines recommend a pond retention time of 8 to 10 days, with at least twice that
time required in warm climates to reduce fecal coliforms to the guideline level of 1,000/100 mL.
Experience at some existing full-scale and demonstration stabilization pond systems indicates that
the desired reductions of helminths and fecal coliform organisms may be difficult to achieve in
practice [Camp Dresser & McKee International, 1993, Huntington and Crook, 1993].
Egypt: Wastewater treatment plants in Egypt treat about one-third of wastewater generated
annually. Most of the effluent is either used directly for agricultural irrigation or discharged to
rivers and subsequently reused. About 42,000 ha (104,000 ac) of agricultural land is irrigated
with wastewater. The irrigation of vegetables with reclaimed water is forbidden and regulations
prohibit the use of effluent for crops unless treated to standards equivalent to agricultural
drainage water. However, food crop irrigation is common, resulting in a high occurrence of
helminth infections. The Ministry of Environmental Affairs began a project in 1998 to irrigate
desert land with treated wastewater from 72 plants for forestry [Radcliffe, 2004]. In Suez,
stabilization pond effluent is used for groundwater recharge by rapid infiltration basins.
Iran: There is little governmental control over water reuse in Iran, and responsibility and
authority for reuse is fragmented. Iran has no water reuse criteria and relies on the WHO
guidelines. It has been estimated that only about 5% of the municipal wastewater is reused via
planned projects [U.S. Environmental Protection Agency, 2004]. Approximately 70 Mm3/yr (18
billion gallons/yr) of primary effluent is used for irrigation. While there are studies examining
the use of treated wastewater for agricultural irrigation, use of untreated wastewater for irrigation
occurs in some locations. The government recognizes the value of reclaimed water and provides
financial incentives in an attempt to encourage water reuse.
Israel: Israel has both arid and semi-arid regions characterized by small amounts of rainfall and
low availability of natural resources and is one of the world leaders in water reuse. Most of
Israel’s 2,000 Mm3/yr (530 billion gallons/yr) of available water supplies are drawn from
groundwater sources. About 25% of that total is surface water from the Sea of Galilee
(Kinnerret Lake) that is transported to southern parts of the country via the National Water
Carrier. Reclaimed water accounts for about 10% of the total water supply and 20% of the total
water used for irrigation. In 1994, about 84% of the wastewater treated in Israel was reused
[Shelef and Azov, 1996]. More than 70% of the treated wastewater in Israel is used for
agricultural irrigation [Kanarek and Michail, 1996]. Much of the irrigation is done using drip
emitters to conserve water, and Israel is in the forefront of the development of state-of-the-art
drip irrigation techniques. There is a goal to reuse 400 Mm2/yr (106 billion gallons/yr) of
wastewater by 2010, which would account for 20% of the country’s total water resources. The
water reuse standards in Israel are similar to those in California, although less restrictive water
quality requirements are acceptable if specific barriers are in place. Barriers options include
level of treatment, storage, drip irrigation, time period before crop harvesting, degree of contact
between reclaimed water and crops, and site characteristics. The two largest projects are the Dan
Region Reclamation Project and the Hakishon Project.
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The Dan Region project, initiated in 1977, provided soil aquifer treatment of 128 Mm3/yr (34
billion gallons/yr) of biologically-treated secondary effluent from the Tel Aviv area in 2003
[Aharoni and Cikurel, 2005]. After a 6-12 month retention in the underground, the extracted
water is piped over 100 km (60 mi) to the Negev area for agricultural irrigation. Industries
pretreat their wastewater prior to discharge to the municipal sewerage system. The Hakishon
Project involves treating 35 Mm3/yr (9 billion gallons/yr) of activated sludge secondary
treatment generated in the Haifa area, blending with other waters, storage in reservoirs about 30
km (19 mi) from Haifa, and irrigation for cotton and other nonfood crops [Aharoni and Cikurel,
2005; Lazarova et al., 2001]. There are numerous stabilization pond systems throughout the
country, mainly in small communities, producing reclaimed water for agricultural irrigation.
Treated wastewater commonly is stored for several months in open reservoirs prior to reuse. In
some cases, winter runoff water is directed for storage in reservoirs containing treated effluent,
resulting in water quality improvements due to both dilution and natural purification processes.
In large urban areas, wastewater receives more advanced treatment, including aerated lagoons,
activated sludge processes, trickling filters, and sequencing batch reactors [Oron, 1998].
Kuwait: Most of the potable supply is either groundwater or seawater that is desalinated by
reverse osmosis treatment. Irrigation accounts for approximately 60% of Kuwait’s water use, of
which 60% is from groundwater and more than 30% from reclaimed water. The major
wastewater treatment plants provide tertiary treatment and a high level of disinfection.
Reclaimed water represents 10% of the total amount of wastewater produced. On an annual
basis, about 25% of the agricultural land and green areas are irrigated with 52 Mm3 (14 billion
gallons) of treated wastewater [Radcliffe, 2004]. Although landscape irrigation applications of
reclaimed water are increasing, agricultural irrigation is by far the main use of the water. A
small amount of reclaimed water is used for groundwater recharge via surface percolation basins.
Requirements are fairly restrictive; irrigation of food crops eaten raw requires tertiary treatment
with water quality limits of 10 mg/L for both BOD and suspended solids and 100 total coli/100
mL. In 2003, construction began on a water reuse facility that will treat 375,000 m3/d (99 mgd)
of wastewater for agricultural irrigation and other purposes after blending with brackish water
[Gottberg and Vaccaro, 2003]. Treatment will include biological secondary treatment, filtration
using disk filters, ultrafiltration, and RO.
Jordan: There are about 20 wastewater treatment plants in Jordan, mainly providing treatment
via stabilization ponds or activated sludge biological treatment. More than 70 Mm3 (18 billion
gallons) of reclaimed water are used each year for irrigation, which accounts for about 10% of
the country’s water supply [Lazarova et al., 2001]. Effluent from stabilization ponds in Aqaba is
used for groundwater recharge by rapid infiltration basins. Reclaimed water usage is expected to
make up about 25% of the total water available for irrigation by 2020. There are some pilot
plant research projects directed at water quality and reclaimed water uses, and a few ongoing
planned agricultural projects exist. In general, most water reuse is unplanned and indirect, i.e.,
wastewater is discharged to water courses, mixed with other water, and used for agricultural
irrigation, particularly in the Jordan Valley. Jordan recognizes the need to incorporate water
reuse into its water resources management plan and is implementing a program to demonstrate
the viability, reliability, safety, and social acceptability of water reuse.
Morocco: Many of the largest cities, particularly those along the Atlantic coast such as
Casablanca, have sewer systems, but discharge untreated or poorly treated wastewater to the
ocean. Much of the wastewater produced in inland cities is reused with little or no treatment for
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all types of agricultural crops, although irrigation of vegetables eaten raw is prohibited. Where
mechanical wastewater treatment plants do exist, almost 70% of them are not functioning
properly, due mainly to a lack of spare parts. This has resulted in high incidences of waterborne
disease. One of the few landscape irrigation projects in Morocco is in Ben Slimane, which is
close to Rabat, where 5,600 m3/d (1.5 mgd) of stabilization pond effluent that meets the WHO
guidelines is used for golf course irrigation. While public participation in reuse projects is not
common in the Middle East, public involvement in a project in Drarga resulted in public support
and included relocating the wastewater treatment plant site.
Oman: Oman has several small tertiary treatment plants producing reclaimed water for
landscape and agricultural irrigation. Reuse regulations are similar to the WHO guidelines,
although they have a more restrictive fecal coliform requirement of 200/100 mL for the irrigation
of food crops eaten raw. A groundwater recharge project involving a seawater intrusion barrier
and replenishment of groundwater used for agricultural irrigation is currently under construction
in Salalah [U.S. Environmental Protection Agency, 2004].
Saudi Arabia: Saudi Arabia has enacted restrictive water reuse criteria for landscape and
agricultural irrigation, which include reclaimed water limits of 10 BOD, 10 TSS, 2.2 total
coli/100 mL, and 1 NTU. The Riyadh North wastewater treatment plant features activated
sludge treatment with nitrification-denitrification, filtration, and disinfection. The reclaimed
water is used mainly for agricultural irrigation, although a small amount is used for industrial
cooling at a refinery. A recent master plan recommended the construction of satellite plants to
provide reclaimed water to local areas for landscape irrigation and industrial and commercial
uses in the city [U.S. Environmental Protection Agency, 2004]. Additional facilities are planned
in other cities that will provide advanced treatment, including reverse osmosis, to produce water
for municipal, industrial, and agricultural applications. The Arabian American Oil Company
(ARAMCO) owns and operates several water reclamation plants. Five facilities in the Eastern
Province provide either secondary or tertiary treated reclaimed water for sod farm irrigation,
discharge to a canal from which diluted water is subsequently withdrawn for agricultural
irrigation, and landscape irrigation – including parks, athletic fields, and residential areas [AlHaidin et al., 2000].
Syria: Population is increasing at a rapid pace in urban areas, resulting in the production of
greater quantities of potable water. This has caused a reduction of the availability of high quality
water for irrigation, thus resulting in the use of untreated wastewater for agricultural irrigation.
Untreated wastewater is commonly used for all types of agricultural irrigation either directly or
after discharge to watercourses.
Tunisia: The main drivers for water reuse in Tunisia are related to water scarcity due to
population growth, an increase in living standards, increasing seawater intrusion in coastal areas,
and accelerated urbanization. Water shortages are becoming an increasingly serious problem in
Tunisia, some of which are associated with environmental pollution. Although only about 30%
of urban and rural households are connected to sewerage systems, approximately two-thirds of
all wastewater produced in the country is treated [Bahri, 1998]. Large urban centers generally
have sewerage systems and provide secondary treatment using oxidation ditches, activated
sludge processes, or stabilization ponds. In 1998 there were at least 44 water reclamation plants
in Tunisia, and currently more than 175 Mm3 (46 billion gallons) of reclaimed water from more
than 60 plants is reused annually. About 35 Mm3/yr (9.3 billion gallons/yr) of reclaimed water is
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allocated for reuse and about 28 Mm3/yr (7.4 billion gallons) are reused. The greatest amount of
reuse occurs in the Tunis area, mainly for agricultural irrigation of fruit trees, fodder crops, sugar
beets, and cereals, although there are several golf courses and parks irrigated with reclaimed
water. A small amount is used for groundwater recharge. Raw wastewater for irrigation is
prohibited, as is the irrigation of vegetables with secondary effluent. Reclaimed water quality
standards are based on the WHO guidelines, guidelines developed by the Food and Agriculture
Organization of the United Nations, as well as a considerable amount of research that has been
conducted by the National Institute for Research on Agricultural Engineering, Water, and
Forestry [Bahri, 1998]. Constraints to increasing the use of reclaimed water include high salinity
of the water, lack of storage facilities to meet peak demands during the irrigation season,
inadequate planning, poor reliability of distribution systems, and inadequate training. Bahri
[1998] identified several knowledge gaps that need to be pursued to reduce uncertainties on
health and environmental impacts, including: development of cost-effective treatment
technologies; fate of microbial and chemical contaminants in the water-soil-plant system; longterm effects of agricultural irrigation on the soil system; risk assessment; decentralized systems
for small communities; and socio-economic considerations.
United Arab Emirates: The most recent data obtained indicate that about 20% of the 500 Mm3
(132 billion gallons/yr) of wastewater produced in urban areas in the emirates was reused in
1995. The most extensive and notable reclaimed water usage occurs in Abu Dhabi, where
nonpotable reuse has been practiced since 1976. In Abu Dhabi, a reuse system designed for
190,000 m3/d (50 mgd) produces tertiary treated reclaimed water for the urban irrigation of
15,000 ha (38,000 ac) of forest land, public gardens, ornamental plants, and roadway medians.
Yemen: Except for the capital city of Sana, which has an activated sludge treatment plant,
stabilization ponds are used for wastewater treatment. Irrigation of all types of food crops is
common and unregulated. One unique use is for the control of desertification in certain areas.
Sana’s activated sludge effluent is discharged to rivers and subsequently extracted by farmers for
agricultural applications; this has served to reduce overexploitation of the aquifer in the area.
Currently, five new water reuse projects are in the process of being activated for agricultural
irrigation and – in one case – for industrial cooling water [U.S. Environmental Protection
Agency, 2004].
3.6 Southern Africa (South Africa and Namibia)
3.6.1 South Africa
South Africa is a semi-arid country with limited water resources, and it is projected that water
demand will exceed available supplies around 2020 [Odendaal et al., 1998]. The main drivers
for water reuse in South Africa include: variable and uneven distribution of rainfall; high
evaporation rates; low-yielding aquifers; and growing industrial and urban development
[Odendaal et al., 1998]. In the past, many of the investigations have been directed at potable
reuse. Intensive research has been conducted at the Stander reclamation plant in Cape Town and
demonstration plants in Pretoria and Athlone, but planned direct potable reuse projects have yet
to be implemented and more attention has recently been given to nonpotable reuse.
Currently, less than 3% of available treated wastewater is directly reused in the country
[Grobicki and Cohen, 1998]. Reclaimed water uses include landscape and agricultural irrigation,
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environmental enhancement, industrial applications, groundwater recharge, and indirect potable
reuse via discharge to rivers. While information on the amounts of reclaimed water used
throughout the country is not available, Grobicki [2000] estimates that less than 30 Mm3m/yr (8
billion gallons/yr) of reclaimed water was reused in 2000, excluding return of treated wastewater
to rivers. In 1998, approximately 9.6 Mm3/yr (2.5 billion gallons/yr) of reclaimed water was
used in the pulp and paper industry, and 4.2 Mm3/yr (1.1 billion gallons/yr) for cooling water
[Grobicki and Cohen, 1998]. Tertiary treated reclaimed water, typically secondary effluent
followed by sand filtration and chlorine for disinfection, is widely used for industrial cooling and
process water, and membranes are beginning to be used for industrial recycling applications.
The Water Act of 1956 requires that any water abstracted from a stream and used for industrial
or municipal purposes must be returned to the stream after treatment, except for that
consumptively used, thus resulting in indirect reuse. Implementation of the Water Act results in
indirect potable reuse, as treated effluents constitute a substantial portion of the base flow in
many of the rivers. In order to maintain high water quality in receiving waters, biological
removal of nitrogen and phosphorus through modified activated sludge wastewater treatment
was pioneered in South Africa and is common.
National water reuse criteria are currently being revised. The existing regulations are stringent
and require that reclaimed water used for the irrigation of food crops eaten raw meet drinking
water standards [U.S. Environmental Protection Agency, 2004]. Unrestricted irrigation of sports
fields, toilet flushing, and irrigation of pasture for milking animals all require that the reclaimed
water receive tertiary treatment and contain zero fecal coli/100 mL. The microbial limit for
discharge to rivers is 126 fecal coli/100 mL, although this coliform requirement can be relaxed
based on case-by-case evaluations.
Grobicki [2000] identified numerous constraints associated with increasing nonpotable reuse in
South Africa. They include:
•
•
•
•
•
•
•
•
•
Access to information;
Constraints on policy initiatives at the local government level;
Constraints in the existing water resource management system in inland areas;
Cost of dual systems and long pipelines;
Health issues with irrigation with reclaimed water;
Concerns regarding contamination of soil and water bodies;
Reservations from potential industrial users;
Concerns regarding reclaimed water quality consistency and reliability of supply; and
Social and religious issues.
3.6.2 Namibia
The only known example of direct potable reuse occurs in Windhoek, Namibia, where highly
treated reclaimed water is put directly into the drinking water system. Water resources are
limited for this city, which has a population of approximately 250,000. The average rainfall is
360 mm (14.4 in) while the annual evaporation is 3400 mm (136 in), and the city relies on three
surface reservoirs for 70% of its water supply. First implemented in 1968 with an initial flow of
4,800 m3/d (1.3 mgd), the Goreangab Reclamation Plant has been upgraded through the years to
its current capacity of 21,000 m3/d (5.5 mgd) [Haarhof and Van der Merwe, 1996]. Industrial
AwwaRF 2006, Used With Permission
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and potentially toxic wastewater is diverted from the wastewater entering the plant. There have
been four distinct treatment process configurations since 1968. The current treatment train was
placed in operation in 2002 and includes the following processes:
•
•
•
•
•
•
•
•
•
•
•
Primary sedimentation;
Activated sludge secondary treatment;
Maturation ponds;
Coagulation/flocculation with FeCl3;
Dissolved air flotation;
Rapid sand filtration;
Ozonation preceded by H2O2 addition;
Granular activated carbon;
Ultrafiltration;
Chlorination/stabilization; and
Blending.
Blending occurs at two locations. The first blending takes place at the Goreangab water
treatment plant, where reclaimed water is blended with conventionally treated surface water.
This mixture is then blended with treated water from other sources prior to pumping to the
distribution system. The percentage of reclaimed water in the drinking water has been relatively
low through the years, averaging 4% between 1968 and 1991 [Odendaal et al., 1998]. The
upgraded plant, however, can supply 35% of the potable water requirements of Windhoek [du
Pisani, 2005]. Chlorine is added to maintain a residual in the distribution system. Extensive
microbial and chemical constituent monitoring is performed on the product water, with several
constituents being monitored continuously using online analytical instrumentation.
Epidemiological studies have not shown any increased disease incidence associated with this
direct potable reuse project [Law, 2003; Odendaal et al., 1998]. Some initial public opposition
to the project has gradually faded, and no public opposition has surfaced in recent years.
In its first year of operation, the reclaimed water treatment cost was $0.46 (US)/m3. If the capital
cost of the facility is added to the cost of the water, the average cost would be $0.77 (US)/ m3.
For comparison, the cost of water from the national bulk water supplier for the same time period
was $0.73 (US)/ m3 [du Pisani, 2005].
3.7 Australia
In the last few decades, Australia has become one of the leading countries in the world in water
reuse. The main driver is lack of adequate water resources in the large urban areas, which
account for 20% of the country’s water use. Although Australia has one of the world’s largest
aquifer systems, only a small percentage is suitable for potable and nonpotable purposes.
Further, only a small percentage of the rainfall in the country runs off into rivers, and more than
one-fourth of Australia’s surface water management areas are close to or overused compared to
their sustainable flow regimes [Radcliffe, 2004].
3.7.1 Applications
There are more than 500 wastewater treatment facilities producing between 150 Mm3 and 200
Mm3 of reclaimed water in Australia annually. In 2002, just over 9% of treated wastewater was
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reused [Radcliffe, 2003]. Reuse is more prevalent in rural inland areas than in large coastal
cities. In Sydney, for example, about 1.3 Mm3/d (340 mgd) of wastewater is treated in 27
treatment systems but only 30,000 m3/d (8 mgd) is reclaimed [Sydney Water, 2002]. Treatment
is commensurate with regulatory standards and often includes nutrient removal. Many plants
provide conventional secondary and tertiary treatment processes, and aerated lagoon and
oxidation pond treatment is common. Wetland systems are sometimes used to improve
reclaimed water quality prior to reuse. Research is ongoing to evaluate the potential of soil
aquifer treatment (SAT) to provide further treatment of secondary effluent prior to extraction and
reuse for horticultural purposes [Dillon et al., 2005].
The Rouse Hill project in Sydney involves a dual water system providing highly treated
reclaimed water to more than 12,000 homes for landscape irrigation and toilet flushing.
Treatment includes tertiary treatment followed by ozonation, microfiltration, and super
chlorination. This project has had several cross-connection incidents, the most recent one
occurring in January 2005 [The Daily Telegraph, 2005]. AWT also is used to produce reclaimed
water. As an example, a treatment train consisting of secondary treatment, microfiltration,
reverse osmosis, and disinfection is utilized to produce reclaimed water for boiler feed water at
the BP Amoco refinery in Brisbane.
Currently, all planned reuse in Australia is for nonpotable applications, although unplanned reuse
does occur more widely than is generally recognized, particularly in the Murray Basin
[Radcliffe, 2004]. Uses of reclaimed water include the following:
•
•
•
•
•
•
•
•
Landscape irrigation (golf courses, parks, residential property, etc.);
Toilet flushing;
Crop irrigation (beef and dairy pastures, fodder and fiber crops, food crops);
Silviculture;
Industrial cooling, boiler feed, and process water;
Commercial uses (horticulture irrigation, turf farms, vehicle washing);
Construction uses (dust control, soil compaction); and
Environmental uses (dune stabilization, streamflow augmentation).
Radcliffe [2004] cited several national policies that have influenced water reuse, including the
National Water Reform Framework, which now includes water reuse as one of its reform
measures. An additional policy driver for water reuse is the National Water Initiative, which was
developed in 2003 and includes the encouragement of water conservation in cities, including
better use of stormwater and recycled water.
3.7.2 Regulations
There is an existing set of national guidelines, entitled guidelines for Sewerage Systems – Use of
Reclaimed Water, which includes a treatment-based classification system but does not have virus
or parasite limits [NWQMS, 2000]. They also provide only limited guidance on urban use,
chemical quality, and environmental impacts [Cunliffe et al., 2005]. The current approach is not
considered to present a sufficient basis for consistent water reuse standards [Radcliffe, 2004].
These guidelines currently are being revised and are being based, in part, on Hazard Analysis
and Critical Point (HACCP) principles. The HACCP system provides a risk management
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framework that focuses on preventing unacceptable health or environmental risks and provides
assurance that water quality requirements will be maintained.
Constitutional responsibility for recycled water in Australia rests with the states and territories.
While guidelines that have been developed are not consistent among the states, they generally
principally address microbial pathogen concerns and are similar in scope to water reuse criteria
developed in the U.S. As an example of reuse criteria imposed at the state level, the Victoria
guidelines are summarized in Table 18.
The Victoria guidelines also include the following:
•
•
•
•
•
•
•
Statutory framework for reuse schemes;
Risk identification and risk assessment;
Roles and responsibilities for suppliers and users;
Treatment and distribution reliability;
Site selection and site management practices;
Monitoring, reporting, and auditing programs; and
Environment improvement programs.
3.7.3 Public Perception/Acceptance
There have been instances where water reuse projects have been modified or abandoned due to
public opposition [Radcliffe, 2004; Marks, 2005]. Some studies on public acceptability of water
reuse for specific applications have been conducted in Australia, which indicate that public
perception of water reuse activities is similar to that in the U.S. Marks [2004] reported that, in
Australia, the medical profession commands the greatest degree of community trust, followed by
public health authorities, research institutions, environmental protection agencies, and nongovernmental environmental groups. Two public opinion studies are summarized in Table 19.
These studies indicated a high level of opposition to potable reuse, as did a 1995 survey in
Sydney, which indicated that 16% of the respondents favored potable reuse [Sydney Water,
1996].
3.8 Far East
Population increase is the main driver for water reuse in most of the Far East, although rapid
industrial growth in some areas, such as China, have drastically increased the need for water and
at the same time has resulted in gross pollution of many of the existing water resources. Water is
scarce in many parts of the Far East, particularly in the northern and western regions of China,
India, and Pakistan. Almost two-thirds of China’s 668 cities have limited water resources and
136 cities experience severe water shortages [Jiménez and Asano, 2002]. The tropical countries
in the Far East generally have abundant water resources and have limited water reuse.
China: It has been reported that there were about 30 water reuse projects either in operation or
under construction in 2004 and that the 10th five year plan includes more than 80 water reuse
projects [EUREAU, 2004]. Much of the water reuse in China is unplanned and results from
abstraction of river water containing wastewater, a great deal of which is industrial effluent.
Current uses of reclaimed water include agricultural irrigation, industrial cooling and process
water, urban landscape irrigation, and toilet flushing in hotels and residential areas. Water
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Table 18. Victoria Water Reuse Guidelines
Class
A
B
Water Quality
Objectivesa
ƒ <10 E. coli100 mL
ƒ <2 NTU turbidityc
ƒ <10 mg/L BOD
ƒ <5 mg/L TSS
ƒ pH 6-9
ƒ 1 mg/L Cl2 residual (or
equivalent)e
ƒ <100 E. coli100 mL
ƒ pH 6-9
ƒ <20 mg/L BOD
ƒ <30 mg/L TSS
C
ƒ <1000 E. coli100 mL
ƒ pH 6-9
ƒ <20 mg/L BOD
ƒ <30 mg/L TSS
D
ƒ <10,000 E. coli100 mL
ƒ pH 6-9
ƒ <20 mg/L BOD
ƒ <30 mg/L TSS
Treatment Processesb
Tertiary and pathogen
reductiond sufficient to
achieve:
ƒ <10 E. coli100 mL
ƒ <1 helminth/L
ƒ <1 protozoa/50 L
ƒ <virus/50 L
Secondary and pathogen
reductiond, including helminth
reduction for cattle grazing
Secondary and pathogen
reductiond, including helminth
reduction for cattle grazing
Secondary
a
Uses Allowed
ƒ Nonpotable urban uses
with uncontrolled access
ƒ Irrigation of food crops
eaten raw
ƒ Industrial uses with
worker exposure
ƒ Irrigation of dairy cattle
pasture
ƒ Industrial washdown
water
ƒ Nonpotable urban uses
with controlled access
ƒ Irrigation of cooked or
processed food crops
ƒ Irrigation of livestock
pasture or fodder crops
ƒ Industrial uses with no
worker exposure
Irrigation of nonfood
crops, including turf,
woodlots, and flowers
Median values determined over a 12-month period, except for pH, which is the 90th percentile.
Where there is a significant risk of direct off-site movement of reclaimed water, nutrient reductions to nominally 5
mg/L total nitrogen and 0.5 mg/L total phosphorus will be required.
c
Turbidity limit is a 24-hour median value determined prior to disinfection. The maximum allowable turbidity is 5
NTU.
d
Helminth reduction is either detention in a pond system for at least 30 days or by an approved disinfection system,
e.g., sand or membrane filtration.
e
Cl2 residual >1 mg/L after 30 minutes is suggested where there is a significant risk of human contact or where
reclaimed water will be within distribution systems for prolonged periods. A chlorine residual of <1 mg/L applies
at the point of use.
b
Source: Adapted from EPA Victoria [2003].
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Table 19.
Summary of Two Public Opinion Studies in Australia
Type of Use
Drinking
Cooking at home
Bathing at home
Washing clothes
Toilet flushing
Home garden irrigation
Park irrigation
Golf course irrigation
% of Respondents Opposed
Sydney Water
ARCWIS
(1999)
(2002)
74
69
62
52
43
30
22
4
4
4
3
3
2
-
Source: Radcliffe [2004]
shortage and pollution concerns in the Beijing-Tianjin area precipitated one of the largest reuse
projects in China, where 500,000 m3/d (130 mgd) of secondary effluent is used for industrial and
agricultural purposes. During the non-irrigation season, some reclaimed water is discharged to
the Tonghui River for flow augmentation [Lazarova and Asano, 2004]. Increasing attention has
been given to wastewater treatment in the last decade, and there are now more than 450
wastewater treatment plants in the country, most of which provide secondary or tertiary
treatment. In 2001, approximately 42,800 Mm3 (11,300 billion gallons) of wastewater was
generated, with industry accounting for almost 50% of the flow. About 35% of the municipal
wastewater received some level of treatment prior to discharge. Taiyuan, for example, is
implementing a master plan – to be implemented by 2010 – to treat about 900,000 m3/d (240
mgd) of its wastewater via enhanced secondary treatment [U.S. Environmental Protection
Agency, 2004]. More than half of the treated wastewater will be discharged to ponds for
groundwater recharge and the remaining effluent will be discharged into the Fen River. The
recharged water will be extracted mainly for industrial process water.
Hong Kong: Seawater has been used to flush toilets for more than 50 years and currently about
640,000 m3/d (170 mgd) is used for that purpose, which is about 20% of the total water
consumption.
Japan: Despite a high annual rainfall and significant surface water collection for drinking
water, Japan’s renewable freshwater availability on a per capita basis is only 5,200 m3/yr (1.4
mgd). Concern over water availability coupled with years of unprecedented drought and rapid
economic growth have resulted in considerable investment in building dams and water supply
reservoirs, extensive water conservation efforts, and wastewater use for nonpotable purposes
[Asano et al., 1996]. The principal applications are toilet flushing, industrial reuse and
environmental reuse (e.g., urban ‘water amenities’) agricultural irrigation, and in-stream flow
augmentation [Maeda et al., 1996]. The criteria and guidelines that apply in Japan are shown in
Table 20. More restrictive regulations apply for landscape irrigation and environmental uses
where incidental body contact with the water may occur.
In 2001, there were 218 publicly owned treatment plants (POTWs) providing 187 Mm3 (49
billion gallons) of reclaimed water mainly for nonpotable urban uses, such as toilet flushing and
environmental purposes. Most POTWs provide either tertiary or AWT for which the
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Table 20. Reclaimed water quality criteria for selected uses in Japan
Parameters
Total coli/100 mL
Chlorine residual, mg/L
Appearance
Turbidity, NTU
Guidelines BOD, mg/L
Odour
pH
Criteria
Toilet Flush
Water
≤10
Trace
Not unpleasant
Not unpleasant
5.8 - 8.6
Landscape
Irrigation
Not detected
≥0.4
Not unpleasant
Not unpleasant
5.8 - 8.6
Environmental
Water
Not detected
Not unpleasant
≤10
≤10
Not unpleasant
5.8 - 8.6
Source: Ogoshi et al. [2000]
government generally provides up to 50% of the capital costs [Asano et al., 2000]. In 1998 there
were an additional 1,500 on-site individual building and block-wide reclaimed water treatment
facilities that provided 71 Mm3 (19 billion gallons) of reclaimed water for toilet flushing [Japan
Sewage Works Association, 1998]. These systems are normally financed by private funds
through low-interest loans. Costs vary, but reclaimed water is usually priced at about 80% of the
cost of potable water. Environmental uses account for 45% of the reclaimed water used in Japan
[EUREAU, 2004]. Reclaimed water also is used for landscape and agricultural irrigation, toilet
flushing, snow melting, and industrial applications. Most of the projects for toilet and urinal
flushing involve onsite facilities with dual distribution systems, often using MBR technology, where
the water is used in school, office, and commercial buildings. The use of reclaimed water is
mandated in Tokyo in all new buildings having a floor area more than 30,000 m2 (300,000 ft2).
India: Only about 72% of the 17 Mm3 (4.5 billion gallons) of wastewater generated annually in
India is collected, and less than 25% of the collected sewage is treated. This has resulted in a
high number of waterborne disease cases in the country. Sewage farms irrigating salad crops
with low quality wastewater are prevalent even though irrigation of vegetable crops with
wastewater is forbidden. India does provide high levels of treatment of industrial wastewater for
reuse. In some cases, reverse osmosis treatment is provided for industrial wastewater, but
tertiary treatment of municipal wastewater is rare.
Korea: Reclaimed water accounts for about 4% of Korea’s water supply. Uses include
industrial cooling water, toilet flush water, and cleaning water. Approximately 430,000 m3/d
(110 mgd) of reclaimed water is used throughout the country and includes about 1,500 individual
block-wide treatment and distribution systems [Jiménez and Asano, 2002].
Pakistan: The use of untreated wastewater for the irrigation of all types of agricultural crops is
common. About 80% of the urban communities use untreated wastewater for agricultural
irrigation, including vegetables. In the City of Faisalabad, for example, more than 2,000 ha
(4,900 ac) of agricultural land is irrigated with untreated wastewater. Farmers prefer to use
untreated wastewater because of its high nutrient value and, although there is one small
wastewater treatment facility in the City, all wastewater used for irrigation is untreated. The
wastewater is sold to the farmers; the revenues generated are used to operate and maintain the
drinking water and sewage disposal systems [U.S. Environmental Protection Agency, 2004].
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Singapore: Much of Singapore’s potable water supplies originate in Malaysia, which presents
potential future water availability problems related to political decisions. In order to increase the
country’s self-sufficiency in the water arena, Singapore has embraced water reuse as part of its
strategy for water independence. The NEWater project, implemented in 2003, produces highly
treated water for both nonpotable and potable reuse at two facilities with a combined capacity of
75,000 m3/d (20 mgd). Treatment includes biological oxidation, microfiltration, reverse osmosis,
and UV disinfection. About 9,000 m3/d (2.4 mgd) of product water currently is used for potable
reuse. The water is discharged into a raw water reservoir and receives a high degree of dilution;
the blended mixture then receives conventional water treatment prior to distribution as drinking
water. Tertiary treated reclaimed water has been supplied to industries in Singapore for more
than 40 years.
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4.0 Desalination of Seawater and Brackish Water
Desalination, the process of removing dissolved solids – primarily salts – from water, is
becoming a viable water supply alternative around the world. Desalination of seawater and
brackish groundwater is in use throughout the world for many purposes, including potable water
for domestic and municipal purposes and industrial processes.
Desalination, also referred to as desalting, is becoming increasingly used as communities
experience population growth, limited local water resources, and more stringent water quality
regulations. Major breakthroughs in treatment technologies and energy recovery equipment in
the 1990s has resulted in the increase of new desalination plants.
Many communities in water-short areas of the world rely on seawater and brackish water
desalination to fulfill their water supply needs. With appropriate investment in research,
desalination may ultimately prove to be the best new supply option for high-valued uses of
water, especially in coastal regions where supply constraints are severe.
The purpose of this chapter is to provide an overview of the use of desalination for seawater and
brackish water applications. The overview will examine the current status of desalination,
summarize the technologies employed, address a number of related issues, and provide a list of
research areas.
4.1 Status
Desalination has become a well-established practice in many parts of the world. Historically,
desalination has been employed in arid regions of the world such as the Middle East and the
Mediterranean and in water scarce areas such as some of the islands of the Caribbean where the
lack of fresh water can severely limit development. Some desert countries, such as Saudi Arabia
and the United Arab Emirates, rely on desalination to meet over half of their water supply needs.
Currently, approximately 15,000 desalination plants operate in more than 120 countries
worldwide producing more than 3.5 billion gallons of potable water a day [Voutchkov, 2004b].
Seawater and brackish water desalination can be used for a number of applications, but the focus
here will be to discuss the use of desalination to produce potable water from saline water sources
for domestic or municipal purposes.
The practicality and cost of desalinating water is directly proportional to the concentration of
dissolved solids and the availability of alternative water sources. The total dissolved solids
(TDS) concentration of seawater ranges from 35,000 mg/L to over 46,000 mg/L in the Arabian
Gulf [Pankratz and Tonner, 2004].
Brackish water contains between 1,000 and 10,000 mg/L TDS and is not generally suitable for
human consumption. This water can often be desalinated more inexpensively than seawater to
provide an alternative source of fresh water. Since most groundwater sources are located inland,
finding environmentally acceptable methods of disposing of the concentrate is often difficult and
costly.
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As shown in Table 21, of the total desalinated water produced globally, about 60 percent comes
from seawater. About a quarter comes from brackish water and the remainder comes from other
sources.
Table 21. World Desalination Capacity by Source (1999)
Source
Seawater
Brackish
River
Industrial/Other
Wastewater
Percentage
59%
26%
6%
5%
4%
Source: Gleick, 2000
A few countries have the majority of the global desalination capacity. Table 22 provides a list of
countries with at least one percent of global desalination capacity as of 1999.
Table 22. Countries with At Least One Percent of Global Desalination Capacity (1999)
Country
Saudi Arabia
United States
United Arab Emirates
Kuwait
Spain
Japan
Libya
Qatar
Italy
Iran
Bahrain
India
Korea
Iraq
Netherlands Antilles
Germany
Percentage
24%
15%
10%
6%
4%
4%
3%
3%
2%
2%
2%
2%
2%
2%
1%
1%
Source: Gleick, 2000
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4.2 Technologies
Desalination technologies separate saline water into two streams: a fresh water stream with a
low concentration of dissolved salts, and the concentrate which contains the remaining dissolved
salts. The installed world capacity consists mainly of reverse osmosis processes and multistage
flash distillation, with the remainder made up of multi-effect distillation, electrodialysis, and
vapor compression. A major characteristic of all desalination technologies is their large energy
requirements. The selection of a desalination process depends on site-specific conditions,
economics, the water quality, the intended use of the water, and local engineering experience.
Table 23 provides a list of available desalination technologies.
Tables 23. Available Desalination Technologies
Major Processes
• Membrane
– Reverse Osmosis
– Electrodialysis
• Thermal
– Multi-State Flash Distillation
– Multiple-Effect Distillation
– Vapor Compression
Minor Processes
• Freezing
• Membrane Distillation
• Solar Humidification
4.2.1 Membrane Processes
Membrane processes account for over half of the world’s desalination capacity. Advances in
membrane technology and performance have led to a much broader application of this
technology. Membranes, which selectively permit or prohibit the passage of certain ions, are
used in seawater and brackish water desalination and represent the fastest growing segment of
the desalination market. The two important commercial membrane desalination processes are
reverse osmosis and electrodialysis. Reverse osmosis systems desalinate seawater at some of the
world’s largest seawater desalination plants. In membrane processes, no heating or phase change
is necessary for separation [Buros, 1999, Gleick, 2000, and Pankratz and Tonner, 2004].
Reverse Osmosis
In reverse osmosis (RO), pressure is used to force fresh water through a membrane, leaving the
salts behind. A semipermeable membrane allows water to pass, but retains salts and solids when
pressure is applied to saline water. Water molecules from the solution are forced through the
membrane. Since RO is a separation process, the volume of water leaving the system (permeate)
is less than the amount of feed water. The resulting concentrate stream is usually 15% or more
of the feed water depending on the initial water quality, the desired water quality of the
permeate, and the technologies employed. As with other separation technologies, the energy
required is directly related to the concentration of salts in the saline water.
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As a result of the steady and continuous improvements in the efficiency of membranes,
installations of RO plants exceed that of thermal technologies. Recent developments have
helped to substantially reduce the operating costs of RO. Lower-cost, higher-flux, higher saltrejecting membranes have been developed that can operate efficiency at lower pressures. In
addition, the development of pressure recovery devices is connected to the concentrate stream to
help reduce energy costs. The overall reduction in the cost of water produced by RO is the result
of advances in membranes, energy recovery, energy reduction, membrane life, control of
operations, and operational experience.
Table 24 lists the largest seawater RO membrane desalination facilities built over the last 10
years and several large facilities in design or construction phases.
Table 24. Large RO Seawater Desalination Facilities
Plant Name/Location
In Operation
Fujairah, UAE
Tampa Bay, USA
Alikante, Spain
Carboneras – Almeria, Spain
Point Lisas, Trinidad
Las Plamas, Telde
Larnaca, Cyprus
Al Jubail III, Saudi Arabia
Muricia, Spain
The Bay of Palma, Palma de Mallorca
Dhekelia, Cyprus
Marbella – Mallaga, Spain
Okinawa, Japan
Under Design/Construction
Ashkelon, Israel
Tuas, Singapore
Cartagena – Mauricia
Hamma, Algeria
Kwinana (Perth), Australia
Tianjin (Dagang)
Capacity
(m3/day)
Completion
(or Target) Date
170,000
95,000
50,000
120,000
110,000
35,000
54,000
91,000
65,000
63,000
40,000
55,000
40,000
2003
2003
2003
2003
2002
2002
2001
2000
1999
1998
1997
1997
1996
325,000
136,000
65,000
200,000
125,000
100,000
2004
2005
2004
2006
2006
2006
Source: Voutchkov, 2004a
Pretreatment is important in RO to keep membrane surfaces clean and operating efficiently.
Suspended solids are removed prior to RO through pretreatment processes to minimize salt
precipitation and microbial growth on the membranes. Pretreatment usually consists of fine
filtration and the addition of acid or other chemicals.
RO membranes are made in several configurations. Two widely available membranes for
seawater and brackish water desalination are spiral-wound and hollow fiber. Post-treatment
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involves stabilizing the water for further use and distribution. The post-treatment consists of
removing gases such as hydrogen sulfide and adjusting the pH.
Electrodialysis
Electrodialysis uses an electric current to move salt ions selectively through a membrane, leaving
fresh water behind as product water. Electrodialysis is an electrochemical separation process, in
which electrical driving forces are used to separate ions in ion exchange membranes. The
process is predominantly used to desalt brackish water. The advantages of electrodialysis are as
follows:
•
•
•
•
Production of more product and less brine;
Energy needs and costs are proportional to the salts removed;
The ability to treat water with a higher level of suspended solids; and
A lower need for chemicals for pretreatment.
Electrodialysis has been used in a wide range of applications. It has been used to produce water
for cooling towers and aquaculture, treat industrials wastes, create municipal supplies, and treat
contaminated groundwater and wastewater.
In the 1970s, a modified version of electrodialysis, called electrodialysis reversal (EDR), was
developed. EDR operates on the same principal as straight electrodialysis except that both the
product and the concentrate channel are identical in construction. At regular intervals, the
polarity of the electrodes is reversed, and the concentrate channel and product water channel
flows are switched. The reversal process breaks up and flushes out scale and other deposits in
the cells. EDR systems operate on feed water with higher turbidity and are less susceptible to
biofouling. EDR can be more cost effective when other water constituents must also be removed
such as hardness.
4.2.2 Thermal Processes
Almost one-half of the world’s desalination capacity uses distillation (or thermal) processes
which are usually employed on seawater sources. These technologies are also used on a smaller
scale for zero liquid discharge (ZLD) systems. Thermal processes involve heating saline water
to produce water vapor that is then condensed to form fresh water. Commercially, the applied
pressure of the water being heated is adjusted to control the boiling point. As the atmospheric
pressure on the water is reduced, the temperature required to boil water decreases. Evaporative
processes can produce high-quality fresh water with a salt concentration of 10 ppm TDS or less
from salt concentrations as high as 70,000 ppm TDS [Pankratz and Tonner, 2004, Gleick, 2000,
and Buros, 1999].
To reduce the amount of energy needed for vaporization, the distillation process involves
multiple boiling in successive vessels, each operating at a lower temperature and pressure.
Another important factor is scale control. Substances such as carbonates and sulfates, which are
found in seawater, can form hard scale that coats surfaces, creating thermal and mechanical
problems.
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Multi-Stage Flash Distillation
In multi-stage flash (MSF) distillation, a stream of heated saline water flows through the bottom
of a vessel containing chambers, or stages, each operating at a slightly lower pressure than the
previous one. The lower pressure causes the hot saline water to begin boiling immediately upon
entering each stage. The rapid, violent boiling action triggers a portion of the seawater to
instantly vaporize, or flash into steam. Since the flashing occurs from the bulk liquid and not on
a heat-exchange surface, scale formation is minimized. As a result, MSF has been the primary
thermal technology used for desalinating seawater since the 1960s. The large energy
requirement for MSF represents a significant disadvantage.
Multi-Effect Distillation
Multi-effect distillation (MED) is a thermal method that has been used for over 100 years and
takes place in a series of vessels operating at progressively lower pressures. This approach takes
advantage of the fact that water boils at successively lower temperatures if the pressure decreases
accordingly. Although some of the earliest desalination plants used MED, MSF units with lower
costs and better scale control have increasingly displaced MED. Recently, interest in MED has
been renewed as new concepts and technologies have come forward.
Vapor Compression Distillation
The vapor compression (VC) distillation process can be used for small and medium-scale
desalination applications, but VC is often used in combination with other processes. The heat for
evaporating the water comes from the compression of vapor rather than the direct exchange of
heat from steam produced in a boiler. VC units are often used for resorts, industries, and remote
sites where fresh water is not readily available. The simple design and reliability of operation
make VC units attractive for small installations.
4.2.3 Other Processes
Other processes have been used to desalinate saline water under certain conditions. These
processes may become more commercially viable with additional research and development
[Buros, 1999 and Gleick, 2000].
Ion-Exchange Methods
Ion-exchange methods use resins to remove ions in saline water. The cost is directly related to
the concentration of salts in the water. Ion-exchange methods have proven effective at lower
concentrations and for small-scale systems.
Freezing
During the process of freezing, dissolved salts are excluded during the initial formation of ice
crystals. Cooling saline water to form ice crystals under controlled conditions can desalinate
water. Freezing has not been a commercial success in the production of fresh water under most
circumstances and may be most suited for industrial waste applications.
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Membrane Distillation
Membrane distillation combines the use of distillation and membranes. In membrane distillation,
saline water is warmed to enhance vapor production. The vapor is exposed to a membrane that
can pass water vapor but not liquid water. The vapor is condensed to produce fresh water. The
advantages of membrane distillation are its simplicity and need for only small temperature
differences. Membrane distillation has only been used commercially on a very small scale.
Solar and Wind-Driven Systems
Solar energy has been used to distill seawater and brackish water. Water vapor produced by
evaporation is condensed and collected. Solar stills have a number of drawbacks including solar
collection area requirements, high capital costs, and weather-related damage. As a result, these
systems are relatively expensive to construct and maintain. The cost of water depends largely on
the cost of producing energy with alternative energy devices. However, some modern desalting
facilities are now being run with electricity produced by wind turbines or through solar electric
technologies, such as photovoltaics. In addition, there are examples of low cost, small scale
solar systems in developing countries to produce drinking water from contaminated source
waters.
4.3 Other Factors
Other factors besides technologies affect the use of desalination as a water supply source.
Factors discussed herein include: economics of desalination; issues with disposing of
concentrate; and reducing overall energy requirements. Other issues that can affect the success
of a desalination facility include permitting and public acceptance.
4.3.1 Economics
The single most important factor limiting desalination has been the high cost of treatment and
delivery. Over time the capital and operating costs for desalination have decreased. At the same
time, the cost of expanding current water supplies through conventional sources is increasing due
to treatment requirements, the limited availability of these sources, and increased demand. The
cost of desalinating water has been substantially reduced by technological improvements in
desalination technologies and in economies of scale associated with larger plants [Alspach and
Watson, 2004, Gleick, 2000, and Buros, 1999]
Many factors affect the costs of brackish water and seawater desalination including capacity and
type of plants, location, feed water, labor, energy financing, concentrate disposal, and plant
reliability. Costs also need to be measured against the costs of other alternatives. In water-short
areas, the cost of desalination is competitive with alternative sources. In many areas, the costs of
brackish water desalination approach the costs of expanding conventional alternatives.
Economic evaluations of water should include all costs involved. These costs include costs for
environmental protection, distribution, and losses in storage and distribution systems.
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4.3.2 Concentrate Disposal
One of the largest impediments to the widespread use of desalination is the resulting high-salt
concentrate stream produced during desalination processes. The disposal of concentrate, which
can account for as much as 50% of the desalination costs, is especially difficult for inland areas
where conventional disposal options are only available for small plants. The concentrate stream
can also be a significant quantity of water, depending on the desalination process. An important
part of the design and operation of desalination facilities is the environmentally appropriate
disposal of concentrate.
Concentrate is characterized by a high level of dissolved solids. Traditional disposal options
include disposal of concentrate in sewers or surface water such as rivers, canals, lakes, and
oceans. Concentrate disposal to the ocean may only require careful attention to dilution,
dissolved oxygen levels, and water temperature. Other disposal options include deep-well
injection into underground aquifers and land-disposal methods such as spray irrigation and lined
evaporation ponds. These alternatives all have limitations, especially as desalination plants grow
in size and number. Larger concentrate streams can affect the quality of surface water,
groundwater, and wastewater effluent. Land disposal can become prohibitively expensive due to
increase land values brought on by population and development demands.
A number of alternative solutions are currently under review. One promising approach may be
to selectively remove some marketable salts such as calcium carbonate from the concentrate.
Selling these separated components can offset disposal costs. Research is also underway to
reduce the energy requirements of thermal processes that can recover as much water as possible
from the concentrate before disposal under a zero liquid discharge (ZLD) approach [Alspach and
Watson, 2004 and Buros, 1999].
4.3.3 Energy Needs
Energy reuse and cost saving techniques are needed to address the high energy requirements
associated with desalination. Many of the recent advances in reducing energy costs have
involved the reduction of the energy required in the desalination processes.
Another approach is the use of “cogeneration” plants in which desalination is integrated into an
energy generation facility. Cogeneration plants can reduce the energy requirements of two
separate facilities, resulting in significant cost savings. Desalination facilities with distillation
systems have been integrated into cogeneration plants in the Middle East and North Africa. This
type of power and water production installation is referred to as a dual-purpose plant [Buros,
1999 and Gleick, 2000].
4.4 Desalination Research Needs
Research and development efforts in the field of desalination are expected to reduce the
production and maintenance costs associated with desalination. Lower costs would make it
possible to produce increased amounts of desalinated seawater and brackish water at competitive
costs. This section provides information on research needs associated with desalination and
includes: findings of the “Desalination Roadmap;” results of the GWRC survey of members;
and the findings of the California Desalination Task Force.
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4.4.1 “Desalination Roadmap” Findings
In 2003, the U.S. Bureau of Reclamation and Sandia National Laboratories jointly facilitated the
development of the Desalination and Water Purification Technology Roadmap (Roadmap) to
serve as a strategic research pathway for desalination and water purification technologies to
contribute significantly to ensuring a safe, sustainable, affordable, and adequate water supply for
the United States [USBR and Sandia, 2003]. In the report, which was intended to serve as a
planning tool to facilitate science and technology investment decisions and as a management tool
to help structure the selection of desalination research, development, and demonstration projects,
critical objectives for desalination technology advancement were determined, and research topics
were identified.
According to the report, some of the factors that are driving the heightened emphasis on
desalination include the following:
•
•
•
The potential to treat saline groundwater;
The need to reduce the cost of water produced through desalination; and
Technologies created through research must be transferred to users.
The Roadmap identified research challenges that need to be addressed, including:
•
•
•
•
Reducing the cost and energy requirements to dispose of concentrates;
Lowering the total cost for desalination processes;
Developing beneficial uses for reject water; and
Minimizing the impacts of the disposal of reject water on receiving ecosystems (i.e., bays,
estuaries, and other habitats).
Aspects of desalination research now being emphasized by USBR include the following:
•
•
•
•
•
•
The creation of smart membranes that sense changes in water quality in real time;
The use of sensors to rapidly detect the formation of biofilms that increase fouling;
Thermal technologies;
Methods to manage concentrate and reject waters;
New approaches to membrane design to increase permeability; and
Developing ways to reduce energy costs.
4.4.2 GWRC Survey Results
The November 2004 GWRC Survey on Water Reuse included a question on issues associated
with desalination. The comments highlighted several common research areas: the need to
address fouling and scaling issues; reducing costs association with treatment, operations, and
energy requirements; addressing concentrate disposal alternatives; and mitigating the
environmental impacts of desalination. The comments received in response to this question are
summarized by topic area below:
Pretreatment
• Address fouling and scaling issues, including pretreatment options that would minimize
membrane fouling and flux decline; and
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•
Develop guidance on pre-treatment requirements for seawater and brackish water
desalination.
Operational Issues
• Examine areas to reduce operating costs in an effort to make desalination more costeffective; and
• Improve water recovery rates, particularly in arid environments where water is a
premium.
Membranes and Desalination Technologies
• Develop lower cost membranes with reduced fouling potential and lower operating
pressure requirements;
• Investigate the risks of membrane failures; and
• Assess different markets for desalination including the use of alternative or innovative
technologies.
Concentrate and Salinity
• Expand upon and/or improve on the available concentrate disposal alternatives
especially for brackish groundwater application for inland areas;
• Research disposal options for concentrate with fewer environmental impacts,
particularly in near shore waters such as bays;
• Examine approaches to remove salts in areas in which the salt load or balance in a
closed loop system of supplying reclaimed drinking water to a community/city is
increasing.
Energy
• Research optimal combinations of power generation and desalination system designs.
Environment
• Develop technologies or strategies that mitigate the environmental impacts of
desalination.
Distribution Issues
• Technologies used to treat water for reuse purposes (including desalination) are
aggressive and thus, can result in a “de-mineralized” or otherwise, “ultra-pure” product
water. These product waters need to be blended with other conventionally treated
waters if they are to be used for potable purposes. Little is currently known about the
impacts of this blended water on distribution system infrastructure or public health.
Other
• Examine the appropriateness of solar desalination for small communities;
• Assess desalination as a viable option in several water stressed regions in Europe
(including London, Southern Spain, Belgium); and
• Addressing the question: what is water reuse and what is desalination?
• Investigate the notion of sustainability of desalination as a potable supply option.
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4.4.3 Results of California (USA) Desalination Task Force Report
California’s Department of Water Resources published a report based on the work of the
“California Desalination Task Force” [DWR, 2003]. The key issues associated with
desalination, according to the report, are listed in Table 25.
Table 25. List of Potential Issues Associated with Desalination [DWR, 2003]
A.
B.
C.
D.
E.
F.
G.
H.
Permitting and Regulatory Issues
A. Information needed
B. Water rights
C. Bay and ocean designated as a drinking water supply
D. International trade issues
E. Science-based approaches
Energy Issues
A. Factors contributing to energy costs
B. Energy use comparisons between desalination and alternatives
C. Issues with co-location with energy and other facilities
D. Methods to reduce costs
E. Green energy markets
Economic Issues
A. Realistic assessment of economic costs
B. Direct and indirect costs of desalination version alternatives
C. Framework for benefit/cost analysis
D. Holistic approach to analysis of water supplies (including water reuse and conservation)
Planning Issues
A. Growth inducement
B. Links between planning and water supply demand
C. Environmental and water quality benefits from brackish water treatment
D. Regional water projections/plans
E. Water supply diversification
F. Small versus large scale approach
G. Multi-jurisdictional cooperation
Siting Issues
A. Land use and infrastructure compatibility
B. Public access
C. Guidelines and criteria
D. Impacts on wetlands and terrestrial habitats
E. Impacts of intake and discharge locations
Feedwater intake
A. Options for feedwater
B. Source water quality, pretreatment and their impacts
C. Entrainment and impingement impacts
D. Affected organisms and how they are affected
E. Ecological impacts
F. Existing and needed mitigation measures
Distribution and Outfall Issues
A. Stability and impact on distribution systems
B. Disposal of residual materials from desalination processes
C. Optimal marine/estuarine substrates for outfall locations
D. Approach to managing concentrate, addressing dispersion
E. Waste stream characterization
F. Water quality, including impacts of blending with power plant, wastewater, or other discharges
G. Ecological impacts of concentrate disposal
Public Health
A. Consumption of product water
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5.0 GWRC Survey Results
In November 2004, GWRC members were surveyed (see Appendix A) on water reuse to support
the GWRC Water Reuse Research Needs Workshop held on April 13-15, 2005 in the
Netherlands. This section provides a synthesis of the survey responses (see Appendix B)
including key factors of success, priority water reuse research needs, potable reuse issues, and
ongoing, planned, and completed research projects.
5.1 Key Factors of Success Identified by GWRC Members
As part of the GWRC survey, members were asked what “key factors of success” would support the
future development of water reuse in their regions. The responses by the GWRC members
supported six overarching factors of success. The six factors are: public trust; pricing and
economics; public health and environmental protection; guidelines and regulations; planning,
management, and applications; and improved technologies and monitoring. Specific comments from
the survey responses are summarized for each of these six areas in this section.
5.1.1 Public Trust
Addressing public trust, perception, and acceptance through public outreach, marketing, water
quality transparency, and technical excellence were noted by respondents to the survey as being
significant issues in determining the success of future development of water reuse.
The following comments were received:
•
Public trust based on a reliable treatment plant, reliable committed staff (management
and operations), transparency with regard to water quality monitoring, and continuous
improvement on all stages and levels. (Southern Africa)
•
Public trust and acceptance are keys to successful water reuse in Southern Africa. For
these factors to be successful, it requires technical process excellence, good public
awareness programs and a high standard of monitoring, which is also fully transparent to
the general users. (Southern Africa)
•
Communities need to be informed of alternative approaches to water recycling and
accepting of new system designs before they are implemented. (Australia)
•
Understanding the social aspects of water reuse, particularly monitoring people’s
reaction to it in homes which have recycled water for toilet flushing and garden watering.
Social research in Australia indicates that the community is willing to support recycled
water for non-personal uses such as garden watering and toilet flushing, but the closer to
personal use of recycled water, the less people like it. Direct potable reuse is not on the
agenda in Australia and is unlikely to be in the medium term. We poorly understand the
communities’ attitudes and perceptions to the vast array of issues that the use of recycled
water raises. (Australia)
•
Public acceptance – the first scheme in the UK that incorporated purposeful indirect
reuse for drinking water supplies was met with negative publicity in the media that led to
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public concern, but only at the final stage of consultation/implementation. The water
utility-concerned have since recognized the need to address the psychological factors
when formulating a communications plan. Redesigning the reuse scheme by discharging
treated wastewater to a watercourse prior to abstraction removed public concern. The UK
has many examples of rivers used for abstraction and discharge, in common with most
developed, densely populated countries. (Europe)
•
Open and honest communication about water reuse, the real anthropogenic water cycle,
the confusion between desalination technology for reuse projects and seawater
desalination, and the fragmentation of the water industry into potable and wastewater
silos as if they are different waters. (Europe)
•
Local flagship project to build trust and prove the benefits. (Europe)
•
Discourage Jay Leno or other prominent public figures from expressing ignorance on the
topic of reuse (i.e., the “toilet to tap” phenomenon). Public education is a key factor of
success. (United States)
•
Addressing public perception and acceptance on the use of reclaimed water for both
nonpotable and indirect potable reuse including addressing psychological barriers such as
breaking the source-quality connection. (United States)
•
Better marketing of reclaimed water including the development of a user-friendly list of
water reuse definitions to replace the current technical jargon (e.g., augmentation water
versus indirect potable reuse). (United States)
5.1.2 Pricing and Economics
Pricing of potable water at its actual value and ensuring that recycled water can be provided at an
economically viable price was a key factor of success for implementing new water reuse projects
cited by survey respondents.
The following comments were received:
•
Pricing water higher and closer to its “true” value will stimulate the reuse of wastewater.
(Southern Africa)
•
Cost (or pricing) of treatment should ideally be less expensive than the cost (or pricing)
of fresh water supplies. (Southern Africa)
•
R&D should continue at a high level to ensure ever-more cost-efficient treatment of
water to ever higher quality standards. (Southern Africa)
•
Reliable and affordable technologies must be available to implement different system
designs for water reuse over a range of scales of operation. (Australia)
•
Politically acceptable pricing policies for drinking and recycled water must be available
to ensure efficient use of valuable water resources. (Australia)
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•
Ensuring that recycled water can be provided at an economically viable price. Obtaining
a greater use of recycled water will be exceedingly difficult if it is priced at a great
premium above alternative sources. To ensure it can compete on price it will be
necessary to use life cycle costing methodologies and delays to future water supply
augmentations to ensure the positive externalities of using recycled water are
encapsulated in the financial assessments. (Australia)
•
Making sure that the price charged is not underpricing the resource or if it is so expensive
that it will preclude its use. Pricing of recycled water is very important and there is
evidence from the Rouse Hill development in Sydney that underpricing of recycled water
compared to the potable alternative has lead to excessive external water consumption and
has prompted residents to fill swimming pools with recycled water to save money. On
the other hand we need to learn from the mistakes that have been made in pricing service
water and ensure recycled water is priced recognizing it will be a scarce resource at some
stage in the future. (Australia)
•
Reduction of costs (for MBR and other membrane technologies). (Europe)
•
Tertiary treatment technologies need to become more cost effective and easier to use so
as to promote more widespread usage at wastewater treatment plants. (United States)
•
Characterizing the full range of costs and benefits associated with water reuse projects
would allow for more informed comparisons of water reuse projects with alternative
projects. Typically, benefits are underestimated for reclaimed water. (United States)
•
The identification of key users of reclaimed water (e.g., industry vs. municipal) and their
respective water quality requirements would be a key factor of success. (United States)
5.1.3 Public Health and Environmental Protection
Greater understanding of potential public health and environmental impacts protection which
would lead to greater public acceptance was cited as a key factor in support of future water reuse
projects.
The following comments were received:
•
Design considerations should be along a risk approach. What are the possible hazardous
substances that need to be removed or taken care of during treatment? How reliable will
each unit (or approach) be to fulfill its purpose? How can sudden changes in the
catchment influence the whole system? (Southern Africa)
•
Availability of wastewater – both in quantity and quality. Wastewater of adequate
quantities and acceptable quality should be available. Obnoxious industrial effluents
should be separated from the wastewater inflow to the treatment plant. (Southern
Africa)
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•
The protection of public health and environmental objectives. The protection of public
health and the environment is an immutable objective; otherwise the potential for
recycling will be set back decades if there is a major public health or environmental
issue. (Australia)
•
Ensuring the plumbing and building industries are adequately trained to minimize the
risk of cross connections. The installation of third pipe systems in new housing
developments to allow recycled water to be used for toilet flushing and garden watering
represents a fundamentally different and new way of configuring water supply and
plumbing networks. Without adequate training of plumbers and the development of
consistent codes of practice, experience dictates that ‘if it can go wrong, it will’ and
therefore the risk of cross connections remains high. (Australia)
•
Making sure that planning law, environmental regulation, public health regulation, and
the developer contributions levied by water utilities all line up to support water reuse.
The existing regulatory planning framework is based on the ‘once through’ approach to
the provision of water infrastructure. If reuse is to be maximized it is essential that all of
the approval authorities recognize the new paradigm we are operating in and amend their
rules and standards. (Australia)
•
A clear understanding of the known public health impacts of reclaimed water quality for
municipal use (direct and indirect) is necessary to overcome the psychological barriers.
(United States)
•
A better understanding of the potential public health impacts of reclaimed water is
needed to address public acceptance. (United States)
5.1.4 Guidelines and Regulations
Respondents to the survey cited uniform water reuse guidelines and regulations as a key factor to
the success of new water reuse projects.
The following comments were received:
•
The development and nationwide application of uniform guidelines for water reuse that
utilize the latest scientific and technical knowledge relating to health risk estimation and
management and the use of technologies for system design and operation (Australia)
•
Reducing impacts of treated effluent on receiving waters. (Australia)
•
Making sure that a “triple bottom” line analysis is conducted and that water resource
outcomes are not pursued at the expense of other objectives such as reducing greenhouse
gas emissions. (Australia)
•
A uniform solution to public acceptance, technology, economics, and hygienic risks for
Europe in the form of supra-national regulations on water reuse in Europe could provide
a sound basis for further development of wastewater reclamation and reuse in many
areas. (Europe)
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•
Agreement in the meaning of the word “appropriate” in European Urban Wastewater
Directive that “treated wastewater should be reused whenever appropriate.” (Europe)
•
Regulatory – there are very few purposeful reuse schemes operating in the UK at the
present time and as a consequence the regulators (Environment Agency, Drinking Water
Inspectorate, Ofwat) do not have policies in place that address their regulation. There is
a need for agreement by all regulators to a common policy or guidelines to be used when
considering proposed reuse schemes. (Europe)
•
Addressing the significant issue of concentrate disposal, especially for inland
communities. (United States)
•
Streamlining institutional requirements such as permitting and regulatory issues
surrounding water reuse projects. (United States)
•
Environmental issues associated with siting or permitting a project. (United States)
5.1.5 Planning, Management, and Applications
Incorporating a holistic view, using uniform planning techniques, innovative applications and
integrating water reuse into the water resources planning and management by municipalities
were identified by respondents to the survey to be important issues in the success of new water
reuse projects.
The following respondent comments were received:
•
Increased government pressure on water demand management. Thus far in the region’s
history, water demand management has not been enforced adequately. Water is generally
under-priced and restrictions only enforced under dire drought conditions. Lower fresh
water consumption means lower income for the water utilities. Water reuse will,
therefore, only be enhanced should increased pressure be placed on water demand
management. (Southern Africa)
•
A uniform planning and institutional framework for water recycling needs to be
developed and accepted nationwide in order to overcome barriers imposed by
inappropriate bureaucratic approval procedures. (Australia)
•
Pursuing water reuse options without taking a holistic view of all of the externalities,
both positive and negative, is likely to deliver suboptimal outcomes for the community.
It is important that a purely water resource criterion is not applied and that a broad
approach is adopted. (Australia)
•
Providing an alternative source of water for nonpotable purposes so that augmentation of
drinking water supplies can be delayed. (Australia)
•
Depending on the main driver, the type of reuse scheme will vary greatly. For instance,
if the driver is reducing the impacts of effluent on a waterway, agricultural schemes are
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preferred as they offer the greatest opportunity to reuse significant quantities of treated
effluent. However, if delaying augmentation of existing supplies is a driver then third
pipe use in new developments and provision of recycled water for industrial/commercial
purposes will be preferred. (Australia)
•
Making sure that planning law, environmental regulation, public health regulation and
the developer contributions levied by water utilities all line up to support water reuse.
(Australia)
•
Water conservation/waste water treatment/surface water quality/ecology are separated in
ways of money, organization and goals. (Europe)
•
Approved institutional framework to allow appropriate reuse projects to be implemented
based on quality, economic, environmental, and social benefits that can be clearly
measured for the alternative solutions. (Europe)
•
A detailed understanding at all levels of integrated water cycle management and the
benefits that water reuse already provide and the opportunities and risks for the future.
(Europe)
•
European standards have to take a complex water policy and management framework
into account and have to balance the protection of water resources, economic and
regional interests, and consumer-related safety standards. (United States)
•
Including water reuse in local and regional planning processes including the use of
Integrated Resources Planning. (United States)
•
For reuse to be successful in the U.S. it needs to be considered in the context of
managing the total water resource needs of a community. As the U.S. population grows,
high-quality source waters are becoming increasingly rare and many communities are
already using water sources that are significantly impacted by treated wastewater. Water
reuse needs to reach a point where it can be considered along with other watershed
management options. (United States)
5.1.6 Improved Technologies and Monitoring
Improved technologies in the areas of membrane fouling, microbial pathogens, and emerging
chemical contaminants should be well researched before being implemented was cited as a key
factor to implement new water reuse projects.
The following comments were received:
•
Design of sewer collection system to separate heavy industrial wastes from domestic
waste. (Southern Africa)
•
Effective pollution control and awareness to industry and households to minimize
“nuisance” pollutants (NaCl, household cleaning agents, organic solvents etc.) (Southern
Africa)
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•
Flexible design of wastewater treatment plant to biologically treat the sewage effluent to
a very high degree. What is meant by that is the following: In the medium and long term
a lot can happen (1) in the catchment area. A lot of “unplanned” developments happen
which do influence the characteristics and flow of the sewage and its treatability AND
(2) different technologies are being developed at a very fast rate and prices become more
competitive, especially in the membrane field. One needs to have the flexibility to
incorporate these new advances if they prove to be reliable in operation and are more
cost-effective. (Southern Africa)
•
Tertiary treatment or reclamation technology, either for irrigation reuse or for drinking
water, should be well researched before implementation. (Southern Africa)
•
Technology excellence. The technology used in the purification of the wastewater should
be efficient, trustworthy, and proven for the task required. (Southern Africa)
•
Efficient operations and monitoring. Consistently efficient plant operation and
monitoring of product water quality should be guaranteed. High-skilled and well-trained
personnel are crucial. Water quality monitoring results should be consistently within risk
management levels, Water quality monitoring methodology should be fully transparent
and results freely available to ensure the public acceptance of this water. (Southern
Africa)
•
Solving the technical problems (fouling and concentrate of membranes) will boost reuse
of WWTP effluent. (Europe)
•
Technical: While nonpotable reuse is growing in the U.S., questions remain about the
potential public and environmental health impacts from microbial pathogens and
chemical contaminants found in treated wastewater. (United States)
•
Addressing emerging contaminants of concern by advanced treatment technologies.
(United States)
5.2 Priority Water Reuse Research Needs
As part of the GWRC survey, members were asked to identify “current research needs related to
water reuse” and “priority water reuse research needs” that could be addressed through the GWRC
or other international research effort. Results of these two questions are organized below by region
and include similar themes as those cited as key factors of success in Section 5.1. The survey
responses are summarized in this section for each of the four regions.
5.2.1 Southern Africa
The following comments were received from respondents in southern Africa:
Public Trust
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•
Identify the cities and towns with highest potential/need for wastewater reclamation, and
the wastewater suppliers and potential users of reclaimed water within these cities and
towns. Opinion and user perceptions need to be determined and strategies suggested for
the facilitation of acceptance of the use of reclaimed water.
Pricing and Economics
•
Further development of analytical methods for water quality analyses. This should
include improved accuracy and improved cost-efficiency.
Public Health and Environmental Protection
•
Endocrine disruptors (including pharmaceutical substances) and viruses are important
health issues that need attention, especially the development of reliable and affordable
test methods.
•
Ensuring microbiologically safe water for improved potability and lower distribution
system microbiologically-induced corrosion. Removal or killing of disinfectant-resistant
organisms should be improved.
Guidelines and Regulations
•
Compile guidelines for the process design of a reclamation plant, taking into account
various possible feedwater qualities and the various possible treated water quality
requirements.
•
Compile risk-based guidelines for reclaimed water quality supplied for various purposes,
as well as risk-based guidelines for the operation and maintenance of reclamation plants.
Planning, Management, and Applications
•
In the book “Guidelines for Water Reuse – James Crook, David Ammerman, Daniel
Okun, Robert Matthews; Camp Dresser & McKee Inc, 1992”, the authors provide
valuable information on reuse. However it leaves a reader wondering how to go about to
implement a reuse scheme with regard to minimum requirements that need to be fulfilled
to successfully implement the project? It’s now 12 years later and a lot of results have
been published or at least reuse schemes have been implemented in the meantime. An
international research team could list all the different case studies in specific categories
and then draw a conclusion of what the minimum requirements should/could be in each
case.
•
Perform research on the upgrading of existing wastewater treatment plants for supplying
a reclamation plant. Include research on the cost-effective integration of the wastewater
and reclamation plants. Special attention should be given to the possible use of
membrane bioreactors and the potential for using a fully membrane-based plant (as from
downstream of the primary settlers in the wastewater treatment plant). Desalination
should also be included as a final option.
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•
Investigate the use of gray water and stormwater run-off as possible sources for water
reclamation.
Improved Technologies and Monitoring
•
In the article published by “Haarhoff J., van der Walt C.J., van der Merwe B. (1998),
Process design considerations for the Windhoek Water Reclamation Plant. WISA
conference, Cape Town, South Africa,” the authors have made a valuable contribution on
the barrier principle in reclamation. Together with work done by the EPA and other
international institutions with regard to the reliability of removal processes, a chapter can
be spent on the different treatment processes and their reliability. (I am not suggesting to
re-write all the design books published already.) What I am suggesting is to list all the
processes that have been successfully used in reclamation and how much log-removal
can be contributed to them (a. from research/application in drinking water field and b.
from full scale applications in the reclamation field.)
•
Ensuring chemically safe water. Perform research on improving the efficiency of
removal of priority chemicals.
•
Perform research on alleviating the fouling of membranes used in the reclamation
process.
5.2.2 Australia
The following comments were received from respondents in Australia:
Public Trust
•
The use of good social science skills to assess and manage community responses to water
recycling proposals.
•
Some research on community attitudes and responses may be influenced by local cultural
and social attitudes, but even in this area, international comparisons of community
behavior can be enlightening.
Public Health and Environmental Protection
•
The control of health risks from human pathogens throughout the full water urban cycle.
This area includes not only understanding the source and fate of pathogens, but also
includes techniques for measurement, speciation, separation and inactivation.
•
Micropollutants and endocrine disrupting chemicals – these pollutants will assume
greater importance as the level of wastewater reuse increases. A good knowledge base
needs to be established to ensure the human and environmental safety of any reuse
scheme and particularly to allay public fears.
•
The design of third pipe systems to avoid or rapidly detect cross connections. The issue
of cross connections is the Achilles Heel for nonpotable recycled water systems and
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designs and/or systems are needed to avoid this potentially catastrophic situation. The
research could be on system design or operation, including methods for rapid detection
etc.
•
Research on pathogens, micropollutants, and small scale treatment technologies.
•
The over riding research need in Australia in relation to recycled water relates to the
public health aspects. This is due to the fact that we are bringing recycled water into
closer contact with people and we can ill-afford to make a mistake. The main public
health research needs can be summarized as follows:
-Measuring and monitoring the reliability of treatment plants to ensure consistent
performance particularly in relation to the removal of pathogens, bacteria, and
viruses.
-Monitoring the effectiveness of the removal of pathogens, bacteria, and viruses in
an ongoing manner.
-Better understanding of the survival/regeneration of pathogens in recycled water
distribution systems.
-Further work is required on exposure assessment to recycled water, particularly
using Quantitative Microbial Risk Assessment methodology using the DALY
metric.
-Development of a predictive capability in assessing public health risks. Examine
data from public health incidents/accidents to determine whether we can use this
data to improve our predictive capability.
Guidelines and Regulations
•
The adoption of appropriate water quality requirements for recycled water taking into
account the need to protect public health, but also ensuring that treatment costs are kept
reasonable. Using QMRA methodology to undertake a review of risks associated with
the use of recycled water and advice on the level of treatment for various uses of recycled
water.
Planning, Management, and Applications
•
The need for reform of planning and institutional procedures which currently hinder
alternative water supply schemes clearly must be addressed at an individual national
level. However, as with research on social attitudes, there is much to be gained by
comparing and contrasting the various national approaches to water supply planning and
institutional oversight. Nothing opens the mind of a government bureaucrat more than
the realization that many other countries do it ”differently.”
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Improved Technologies and Monitoring
•
The development of water treatment technologies which can be designed to operate
reliably over a range of scales (e.g. household to small community scale).
5.2.3 Europe
The following comments were received from European respondents:
Public Trust
•
Public acceptance. Identification of factors that lead to successful implementation of
reuse schemes, particularly public acceptability.
Pricing and Economics
•
The economy of water reuse projects has to be rethought in terms of a broader “water
value” concept and the incorporation of externalities.
•
Economic externalities to clearly measure the benefit of reuse projects compared to the
alternatives.
•
The economic benefit of water reuse to the local community with regards to food
production, industry, employment, water resource availability, urban parks, land
revaluation, flood prevention and tourism.
•
How much does recycled water cost to produce in dollars and energy and what do
operators around the world sell it for and why that price?
Public Health and Environmental Protection
•
The water quality issues have to be connected through a quantitative risk assessment to
environmental and human health risk issues.
•
Emerging contaminants.
•
Food safety aspects of using reclaimed water for crop irrigation.
•
Epidemiological evidence of the impact of indirect potable reuse on health.
•
Reuse as a solution to climate change (energy consumption, droughts, floods, increase
seawater ingress due to rising sea levels)
Guidelines and Regulation
•
Common regulatory policy.
•
Quality criteria for water reuse applications.
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Planning, Management, and Applications
•
New city development and the benefits of integrated water cycle management strategies.
•
How can water reuse and unused power generation capacity provide energy storage
during off peak periods?
•
Development of sustainable systems using non-fossil fuels.
•
Water reuse – water and nutrient reuse for optimization of food production.
•
Best practice for golf irrigation.
Improved Technologies and Monitoring
•
New technologies for water application.
•
Treatment technology evaluations should be extended to emerging pathogens and
contaminants issues.
•
Ability of treatment processes to remove/inactivate endocrine disrupting substances,
pharmaceutical residues, viruses.
•
Behavior of trace organics in water reclamation systems.
•
Integration of wastewater reuse in total water cycle management.
•
Treatment technology evaluations should be extended to emerging pathogens and
contaminants issues.
•
MBR technology (reducing costs, solving operational problems, quality increase).
•
MBR post treatment (NF/RO, NOM/biofouling, concentrate solutions).
•
EDCs, pharmaceuticals, NDMA and other emerging compounds (comparison of different
technologies to cope with these pollutants).
•
UV disinfection (effectiveness).
•
Advanced oxidation (UV-peroxide, ozone, effectiveness, post treatment).
5.2.4 United States
The following comments were received from respondents in the United States.:
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Public Trust
•
Public participation. Better understanding of the public’s perception and acceptance of
water reuse (nonpotable and indirect potable reuse)
Developing better marketing strategies for water and wastewater agencies.
•
Better characterizing the economics (including benefits) of water reuse.
•
Pricing and Economics
•
Much research is being accomplished with regard to concentrate streams from reclaimed
and desalination treatment processes, however there is no doubt much left to be
researched and understood. Beneficial uses (or reuse, including marketing) of
concentrate need to be identified and researched.
Public Health and Environmental Protection
•
There is a need to investigate and identify the long term impacts of reused water on
commercial and residential landscape, as reused water continues to meet the demands of
water utility customers. For example, Denver Water's future supply is projected to be
30% reused water, and they are being told that reused water is killing the conifers. What
are the soil concentration build-ups that result from reusing water to irrigate?
•
Risk assessment should be tied to regulatory efforts in reuse. Currently, no water reuse
criteria in the U.S. are based on strict risk assessment methodology. Including risk
assessment as one of the tools used to develop scientifically-based criteria would result in
more rational and defensible criteria and increase pubic acceptance of such criteria.
•
Whole effluent toxicity measurements for reuse applications.
•
Fate of anthropogenic chemicals and pathogens in reuse applications.
•
Fate and transport of chemicals and pathogens following irrigation.
•
Public health implications for potable reuse.
•
Effects of storage on water.
•
Addressing “emerging pollutants of concern” or EPOCs including endocrine disrupting
compounds, pharmaceuticals, household and personal care products, and other
substances that remain as trace micropollutants in treatment wastewater effluent. Topics
include: public health implications, removal by current treatment technologies, and the
development of new generation technologies.
•
The fate and transport of chemicals and pathogens during irrigation with reclaimed
water.
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Planning, Management and Applications
•
The increased use of “nontraditional” water sources including: treated municipal and
industrial effluents; storm water; agricultural runoff; brackish ground water and other
impaired ground waters; and ocean water.
•
The use of aquifer storage and recovery (ASR) to store reclaimed water on a seasonal
basis or for long-term storage for nonpotable applications. In addition the use of aquifer,
storage, transfer, and recovery (ASTR) in which separate recovery wells are used.
•
The use of groundwater recharge and surface water augmentation as indirect potable
reuse.
Improved Technologies and Monitoring
•
Advances in technologies are needed to cost-effectively and reliably create new sources
of water from “nontraditional” water supplies by removing a wide range of contaminants
than is possible with conventional water treatment processes. Possibilities include
advances in membrane technologies, advances in thermal techniques, and the
development of alternative technologies.
•
Advances in managing the concentrate and residuals from membrane treatment including
alternative disposal options, volume minimization technologies, zero liquid discharge
technologies, and beneficial uses of concentrate and separated salts.
•
As an alternative approach to centralized water recycling facilities that collect, treat, and
redistribute reclaimed water to customers over broad geographic areas, satellite water
recycling centers are beginning to provide cost-effective, localized, reclaimed water use
opportunities. Satellite water recycling centers (sometimes called scalping plants) treat
the liquid wastewater phase and convey the residual solids to the centralized wastewater
treatment plants while providing the treated, reclaimed water for localized applications.
This approach is developing at a more rapid rate in recent years by small and large
utilities alike. More technical study of this technique now appears warranted from the
standpoints of collection system impacts, concentrated waste stream treatment impacts at
the centralized plants, and for the potential satellite operational and customer impacts
that might be associated with this reuse application. This information would be very
valuable for reuse program planning and to help establish proper regulatory guidelines
for these facilities that often aren't currently addressed on a state-by-state basis as this
approach continues to emerge as viable reuse technology.
•
Efficacy of existing and new reclamation treatment processes.
•
Removal and/or inactivation of pathogens during treatment.
•
Evaluation of reliability issues for membranes and other processes.
•
Evaluation of advanced oxidation processes and biological processes to produce
biologically stable reclaimed water.
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•
Improved treatment technologies.
•
Removal and inactivation of potential pathogens.
•
What are the appropriate indicators for pathogens.
•
The use of satellite and decentralized treatment for water reuse applications.
5.3 Potable Reuse Issues
GWRC members were surveyed on the specific issue of potable reuse. Member responses varied
from region to region. Specific comments from the survey responses are summarized for each of
the four regions in this section.
5.3.1 Southern Africa
Public Trust
•
The rural populations in South Africa are very uneducated and illiterate.
Guidelines and Regulations
•
There are drinking water guidelines on national and international level, but there are no
international guidelines for wastewater reused/reclaimed to drinking water level. Maybe
consideration should be given to this subject.
Improved Technologies and Monitoring
•
Because of the long treated water distribution distances under hot temperature conditions,
research is required on water quality changes in the distribution system, as well as
distribution system changes due to the water quality.
5.3.2 Australia
Public Trust, Pricing and Economics, Environmental Protection
•
Potable reuse is not being considered as a realistic option in Australia, chiefly because of
the community’s strong aversion to such an idea. Most of Australia’s cities get their
water supplies from sources largely uncontaminated with human waste, which means that
not even indirect potable reuse is practiced. Adelaide may be the only exception here, but
even in this case the level of sewage discharge to the Murray River is miniscule as a
percentage of the total flow. Having said this, there may be situations arising in the future
where potable reuse is a better option from both an environmental and economic
perspective. However, the barrier of public acceptance would still remain. Consequently,
Australia would have an interest in any project investigating public attitudes to potable
reuse.
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Planning, Management, and Applications
•
Potable reuse is not on the agenda in Australia and is not likely to be for a long time.
Apart from strong community resistance to the concept, there is no need for Australia to
embark on this journey when we have many other water resource options we can pursue
before we are forced into considering potable reuse. Bear in mind the number of
instances of direct potable reuse throughout the world are few and far between.
5.3.3 Europe
Public Trust
•
Lack of understanding of the term potable reuse (except by an enlightened few) due to a
lack of understanding of the real water cycle.
•
Public acceptance.
Public Health Protection
•
Food safety aspects of using reclaimed water for crop irrigation.
Planning, Management, and Applications
•
In central Europe planned indirect potable reuse is only practiced in one case
(Wulpne/Torreele), the issues of unintended direct potable use through ground and
surface water augmentation by effluents have to be considered on a more “reuse linked”
basis.
5.3.4 United States
Public Trust
•
Public perception is a major hurdle in the United States to widespread adoption of reuse
for either indirect or direct purposes. Education of the public is a tricky and challenging
task, exacerbated by regional concerns (e.g., water availability, political atmosphere, etc.)
and regulatory concerns (e.g., CWA vs. SDWA). The State of the Science report should
include this as a special consideration for the North American application.
•
While there are successful indirect potable and non-potable reuse projects around the
country there still remain significant barriers to public acceptance of direct potable reuse.
Much of this resistance is based on the persistent scientific uncertainty that remains about
the level of removal of pathogens and trace organic compounds.
•
Indirect potable reuse is practiced in the United States by several communities. These
well-planned, well-engineered water supply projects (e.g., Orange County’s Groundwater
Replenishment System, Scottsdale’s Water Campus, and West Basin Municipal Water
District’s Water Recycling Facility) are considered to be very successful and are held up
in their communities as significant achievements. In the past few years, however, several
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proposed indirect potable reuse projects have stalled or have been canceled primarily due
to public opposition.
•
More communities in the U.S. are considering indirect potable reuse to meet increasing
water supply demands. Currently, however, indirect potable reuse can only be permitted
in a handful of states. In addition, water agencies proposing indirect potable reuse
projects are still confronted with significant public opposition. As a result, agencies
considering indirect potable reuse must address the significant issue of public acceptance
before a project will be approved by decision makers (i.e., elected officials, senior water
agency managers, etc.).
5.4 Ongoing, Planned, and Completed Research Projects
GWRC members were surveyed on their “ongoing, planned, and completed research project” in their
regions. Survey responses can be found under “Question 7” for each respondent in Appendix B of
this report.
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6.0 Summary
Water reuse is an established and growing practice in many regions of the world. Water stress
(i.e., scarcity of renewable freshwater resources due to population increases, industrial
development, droughts, and global climate changes) is the principal driver for water reuse in
most countries.
Water reuse also is driven by other factors such as regulatory
policies/regulations or lack thereof, public policy, availability of treated or untreated wastewater
at less (or no) cost compared to potable water, environmental enhancement, pollution abatement,
and reliability of supply. Reclaimed water is now considered to be an integral component of
water resources management in many countries and regions, including Australia, Europe, Israel,
and the U.S.
The public strongly supports water reuse for most nonpotable uses, although in some Muslim
countries the use of wastewater for irrigation has been opposed on religious grounds. Public
acceptance surveys, mainly conducted in the U.S. and Australia, indicate that 50% or more of
respondents are opposed to potable reuse, while 5% or less are opposed to irrigation or similar
uses in urban areas. People generally favor reuse where there is minimal contact with reclaimed
water, and the stated reasons for opposing various types of water reuse almost always revolve
around health protection. Health concerns were among the stated reasons given for the recent
failure of three planned indirect potable reuse projects in the U.S. Nonpotable reuse projects in
several countries have been delayed, modified, or abandoned due to public opposition.
Uses of reclaimed water range from agricultural irrigation of nonfood crops with minimally
treated wastewater to potable reuse, where extensive treatment is needed. Agricultural irrigation
represents the major use of reclaimed water in many countries, particularly in the Middle East
and Latin America where the water often receives minimal treatment, while the trend in many
industrialized countries has shifted to landscape irrigation in urban areas, industrial and
commercial applications, and potable reuse. Dual water systems supplying reclaimed water for
landscape irrigation, toilet flushing, and other nonpotable purposes are prevalent in the U.S.,
Australia, and Japan.
Planned indirect potable reuse is practiced in selected regions, mainly in the U.S., South Africa,
and Europe. In contrast to projects in Europe and South Africa where reclaimed water is
discharged to rivers for subsequent abstraction as drinking water, most potable reuse projects in
the U.S. involve groundwater recharge of reclaimed water to potable aquifers. There are no
potable reuse projects in Australia. The only planned direct potable reuse installation in the
world is at Windhoek, Namibia. Unplanned or incidental nonpotable and potable reuse resulting
from the abstraction of surface or groundwater containing municipal wastewater occurs
throughout the world.
The level of removal of microbial or chemical contaminants is dependent on the use to be made
of the reclaimed water. For nonpotable applications where human contact with reclaimed water
is expected or likely, microbial water quality is paramount, although specific uses, such as some
industrial applications, require control of chemical constituents. While heavy metals and other
chemical constituents in wastewater used for agricultural irrigation can present health concerns,
municipal wastewater that has received at least secondary treatment generally is acceptable,
although wastewater containing a high percentage of industrial wastes warrants attention.
Potable reuse requires removal of both microbial and chemical constituents of health concern.
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Conventional wastewater treatment has been shown to eliminate known pathogens or reduce
them to acceptable levels for all uses of reclaimed water, although concern about emerging
pathogens has been expressed by some public health experts. Chlorine is the most widely used
disinfectant on a worldwide basis, although UV radiation is becoming more common in
Australia, Europe, and the U.S. A major advantage of UV is its ability to inactivate
Cryptosporidium and most viruses. The use of untreated or poorly treated wastewater for the
irrigation of food crops and where unplanned potable reuse is occurring has resulted in high
infectious disease rates in China and India and many developing countries in the Middle East and
Latin America.
Chemical contaminants represent the major concern associated with planned potable reuse,
particularly toxic chemicals of industrial origin, EDCs, PhACs, and PCPs. Research in Europe
and the U.S. has documented the presence of many zenobiotic compounds in treated wastewater.
Much of the research conducted to date has been directed at the presence, concentration, and
effects of zenobiotics on the aquatic environment, where adverse effects on aquatic animals have
been observed. Less is known about potential health effects associated with ingestion of water
containing such compounds. AWT (particularly RO, GAC, advanced oxidation, and ozone),
dilution, and degradation in the environment have been shown to reduce many EDCs, PhACs,
and PCPs to low or immeasurable levels, leading some experts to conclude that there are
insignificant health risks, while others suggest that the possibility of additive or synergistic
effects have not been adequately documented. Knowledge gaps in this area revolve around
treatment process efficiency, analytical methodology and monitoring techniques, and risk
assessment. Antibiotic resistance in microbial pathogens has been observed, and more study is
needed to determine the extent and gravity of antibiotic-resistance in microorganisms and
microflora as a result of the presence of PhACs in municipal wastewater.
Application of treatment technology is similar in industrialized countries, where mechanical
wastewater treatment processes dominate, although treatment via stabilization ponds, lagoons,
wetlands, and other low technology systems also is common. Conventional biological secondary
treatment, tertiary treatment via media or membrane filtration – often including nutrient removal
processes, and disinfection with chlorine or UV is standard practice for most nonpotable
applications of reclaimed water. AWT processes are the norm for potable reuse treatment
facilities; examples of processes currently used for potable reuse at signature projects in the U.S.,
Europe, Namibia, and Singapore include chemical precipitation, ion exchange, GAC, RO, ozone,
and advanced oxidation.
Water reuse regulations and guidelines for nonpotable applications of reclaimed water differ
widely around the world and often within countries. In the U.S., there are no federal water reuse
regulations, and criteria are developed at the state level. California’s Water Reuse Criteria have
served as the basis for regulations in several other states (and countries), although several states
have regulations that are considerably less restrictive than those in California. While Australia
has national reuse regulations, the states and territories have implemented their own standards,
which are similar in scope to criteria in the U.S. but – as in the U.S. – are not consistent among
the states. There are no standardized water reuse standards for the entire European community,
and not all countries have adopted regulations or guidelines. Some countries or regions of
countries have imposed restrictive standards similar to those in Australia and the U.S., while
others base their standards on the WHO guidelines for wastewater use in agriculture and
aquaculture. The WHO guidelines (currently under revision) are much less restrictive than those
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in the U.S., Australia, and some other industrialized countries and are favored in the Middle East
and Latin America. The WHO guidelines include recommended limits for intestinal nematodes,
which are not considered to present a major health concern in most industrialized countries and,
thus, are not included in most regulations or guidelines in those countries.
Most, but not all, reuse regulations and guidelines include both treatment process and water
quality requirements/recommendations, and generally specify limits for either total or fecal
coliforms, turbidity or suspended solids, and BOD. Few regulations directly include limits for
viruses and instead rely on treatment processes and surrogate organisms to indicate virus
removal. There are few examples of potable reuse regulations; those that do exist require high
levels of treatment to insure that all drinking water limits are met and include limits for
nonregulated contaminants or surrogate parameters such as TOC.
Desalination of seawater and brackish water for potable and other uses via membrane and
thermal processes is increasing throughout the world, due mainly to major breakthroughs the last
two decades in treatment technologies. RO membrane efficiencies have improved, and
distillation processes have been integrated into cogeneration plants where energy also is
produced. Desalination is used to produce more than half of the water supply needs in some
arid countries, such as Saudi Arabia and the United Arab Emirates. Desalination technologies
are costly to build and operate, thus limiting their use in regions not having the financial
resources to afford them. Concentrate disposal is a major impediment to desalination in many
areas, particularly at inland sites. Current research activities include development of lower-cost
membranes with greater efficiency and innovative, cost-effective methods of concentrate
disposal.
A survey of GWRC members recently was conducted to gather opinions and information on
several aspects of water reuse, including identification of key factors of success for their regions.
While specific factors identified by the members varied considerably, a synthesis of the
responses resulted in identification of six overarching factors that are key to the success of future
development of water reuse. The overarching factors are: public trust; pricing and economics;
public health and environmental protection; guidelines and regulations; planning, management,
and applications; and improved technologies and methods. The survey also queried the members
on priority research needs and ongoing, planned, and completed research projects in their
regions. The information obtained from the survey is included in Appendices A and B. Clearly,
the GWRC members are engaged in numerous high priority research projects to address current
knowledge gaps associated with water reuse and desalination, and future collaborative efforts
will significantly enhance knowledge in this arena.
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APPENDIX A
GWRC Water Reuse Survey Form
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GWRC Survey on Water Reuse
Revised November 9, 2004
Purpose:
The objective of this survey is to solicit input from GWRC members on
water reuse to support the development of a “State of the Science” report in
advance of the GWRC Water Reuse Research Needs Workshop scheduled
for April 11-13, 2005 in the Netherlands. The Workshop is intended to
assess and prioritize research needs on water reuse for future collaboration
by GWRC members.
Instructions: Please complete this survey by December 1 and email the form to
[email protected]. Consider both potable and nonpotable water
reuse applications.
Questions:
If you have questions about this survey, please contact Jeff Mosher with the
WateReuse Foundation at [email protected] or (703) 684-2481.
Additional information on the Workshop will be forwarded to GWRC
members.
General Questions
1. Provide the following information:
ƒ
ƒ
ƒ
Name:
Organization:
Email:
2. Will you be attending the GWRC Water Reuse Research Needs Workshop
scheduled for April 11-13, 2005 in Utrecht, Netherlands?
ƒ
Yes/No:
3. If others from your organization are planning to attend the Workshop please
provide the following information:
ƒ
ƒ
ƒ
ƒ
Name:
Title:
Expertise:
Email:
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4. If you are planning to have other expert(s) attend the Workshop please provide
the following information:
ƒ
ƒ
ƒ
ƒ
Name:
Affiliation:
Expertise:
Email:
Technical Questions
5. List available reports or publications by your organization or other
organizations that provide an overview of water reuse in your country/region.
Include documents and papers that address or include research needs for
water reuse. Indicate if the reports are available electronically.
6. What are the key factors of success that would support the future development
of water reuse in your country/region? Provide a description or rationale for each
factor of success. Possible factors include: economic, financial, psychological,
regulatory, organizational, technical issues.
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7. Provide a list (and include descriptions) of your organization’s ongoing,
planned, and completed research projects related to water reuse.
8. Provide a list of your organization’s current research needs that are related to
water reuse and prioritize if possible.
9. As the GWRC representative for your country/region, provide a list of priority
water reuse research needs that you feel can or should be addressed through
the GWRC or other international research effort.
The research needs can be in the form of: 1) topic areas of concern (e.g.,
water quality, treatment technologies, public health, public acceptance, etc.); 2)
project descriptions for research ideas; or 3) issues/problems that need to be
solved.
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10. Are there any special considerations in your country/region associated with
potable reuse that should be considered in the State of the Science report?
11. List any other information that you feel should be considered in developing the
State of the Science report. For example, are there emerging trends in the field
or reuse, innovative technologies on the horizon, barriers or obstacles to reuse
that need to be addressed, or institutional or regulatory needs?
12. The WateReuse Foundation believes that water reuse and desalination issues
are merging (e.g., both make use of impaired waters, both involve advance
treatments, and both can experience public opposition). Should desalination
be discussed during the workshop?
If yes, what are the primary desalination issues and/or research needs in your
country/region?
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13. Would you or have interest is making a presentation at the workshop on
“pressing needs and challenges” related to water reuse in your
country/region?
∗ ∗ ∗ END OF SURVEY ∗ ∗ ∗
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APPENDIX B
GWRC Water Reuse Survey Results by Region
B.1 – Africa
B.2 – Australia
B.3 – Europe
B.4 – United States
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APPENDIX B.1
Africa
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GWRC Survey on Water Reuse
Namibia (Africa)
Contact: Jürgen Menge
[email protected]
Q5. Reports or publications,
[ELECTRONIC COPY OF ARTICLES CAN BE SUPPLIED ON REQUEST]
including those that address
research needs for water
1995
WATER TREATMENT AND RECYCLING - MAINTAINING THE WATER QUALITY - Menge JG [ESI] (1)
reuse
1996
TWENTY-FIVE YEARS OF WASTEWATER RECLAMATION IN WINDHOEK, NAMIBIA - J. Haarhoff and B. van der Merwe [ISWRR] (2)
1996
1998
WATER RECLAMATION FOR POTABLE REUSE IN WINDHOEK NAMIBIA - Ben van der Merwe and Jürgen Menge [WATERTECH] (3)
PROCESS DESIGN CONSIDERATIONS FOR THE WINDHOEK WATER RECLAMATION PLANT - J HAARHOFF, CJ VAN DER WALT
AND BF VAN DER MERWE [WISA] (4)
1999
Toxicity testing at Goreangab Reclamation Plant – past, present and future - J G MENGE and J L SLABBERT [ISTA] (5)
2000
OCCURRENCE AND REMOVAL OF GIARDIA AND CRYPTOSPORIDIUM AT THE GOREANGAB RECLAMATION PLANT - J G
MENGE, J HAARHOFF, E KÖNIG, R MERTENS and B VAN DER MERWE [IAWQ/IWSA] (6)
2000
ULTRAFILTRATION AS A TREATMENT PROCESS FOR DIRECT WATER RECLAMATION IN WINDHOEK. - E. H. KÖNIG, I. W. VAN
DER MERWE and S. WADLEY [IAHR] (7)
2000
Pollution prevention from industrial activities in Windhoek. - M Ahmed, L Ilonga [IAHR] (8)
2000
Scientific Services, a partner in engineering and in water and wastewater management - J MENGE, E KÖNIG [IAHR] (9)
2000
Trickling Filters: Integration into the Total Re-use Water System at Gammams Water Care Works - JG Menge, AM van Niekerk, Rudert
[IAHR] (10)
2000
APPLYING ULTRAFILTRATION AS POLISHING PROCESS IN DIRECT WATER RECLAMATION AT WINDHOEK, NAMIBIA - E H
KÖNIG and I W VAN DER MERWE [WISA] (11)
2001
WATER RELATED TASTE AND ODOUR: A seasonal reality or just an occasional nightmare? - ERICH H. KöNIG and JüRGEN G.
MENGE [WAN] (12)
2003
ADVANCED REUSE – FROM WINDHOEK TO SINGAPORE AND BEYOND – Law IB, (May 2003) Water, Australia
Two reports in hard copy. Not available in electronic format.
Burmeister Van Niekerk (Consulting Engineers). (1992) Report on the upgrading and extensions of Goreangab reclamation works. Submitted to
the City of Windhoek in October 1992.
Van der Merwe, B., Peters, I. and Menge, J.G. (1994) Case study of the re-use of purified effluent in Windhoek, Namibia. City Engineer's
Department, City of Windhoek, Republic of Namibia.
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Q6. Key factors of success
that would support the future
development of water reuse
KEY FACTORS
The following notes are more related to experience in Windhoek, Namibia.
1.
2.
3.
4.
5.
6.
7.
Q7. Ongoing, planned, and
completed research projects
General: Public trust based on reliable treatment plant, reliable committed staff (management and operations), transparency with regard
to water quality monitoring, continuous improvement on all stages and levels.
The objective should be well defined. Design considerations should be along a risk approach. What are the possible hazardous
substances that need to be removed or taken care of during treatment. How reliable will each unit (or approach) be to fulfill its purpose?
How can sudden changes in the catchment influence the whole system?
Design of sewer collection system to separate heavy industrial wastes from domestic waste.
Effective pollution control and awareness to industry and households to minimize ‘nuisance’ pollutants (NaCl, household cleaning
agents, organic solvents etc.)
Flexible design of wastewater treatment plant to biologically treat the sewage effluent to a very high degree. What is meant by that is the
following: In the medium and long term a lot can happen (1) in the catchment area. A lot of ‘unplanned’ developments happen which do
influence the characteristics and flow of the sewage and its treatability AND (2) different technologies are being developed at a very fast
rate and prices become more competitive, especially in the membrane field. One needs to have the flexibility to incorporate these new
advances if they prove to be reliable in operation and are more cost effective.
Tertiary treatment or reclamation technology, either for irrigation re-use or for drinking water, should be well researched before
implementation.
With regard to specific technology, each site or situation will have its preferences.
Planned Research
1.
2.
3.
4.
5.
6.
Characterisation of Natural Organic Matter (Which fractions are removed during various process stages?)
Bromate formation potential at NGRP (How much Bromate is formed by the Ozone barrier?)
Endocrine Disruptors (Their presence in raw water and removal thereof during reclamation)
Membrane Fouling (What causes the fouling and how can it be minimized/removed?)
Limnology (The Goreangab Dam pollution is increasing. The water is getting very difficult to treat – To study the Limnology of the Dam
and come up with remedial actions to rehabilitate the water to make it ‘more treatable’.)
Enteric Viruses monitoring at the plant (Removal of virus during various treatment stages using the latest concentration and analytical
techniques).
Completed research
Projects conducted between 1991 – 1998
The Scientific Services of the City of Windhoek has been actively involved in numerous projects in the water and wastewater field together
with the engineering division. An overview will be given of the projects, which resulted in full-scale treatment plant upgrade or changes.
Water treatment
An extensive investigation to optimise and determine the maximum capacity of the old Goreangab Reclamation Plant (OGRP) was
conducted during 1991 and 1992. Each single process unit was scrutinized and options and alternatives were carefully evaluated. This
resulted in quite a lot of changes and recommendations to upgrade and extend the capacity of the existing plant from 4 Ml/d to 7 Ml/d
(Haarhoff J. 1991).
The changes and alternatives included the following:
1. Breakpoint chlorination
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To provide three barriers in the treatment train, chlorination took place at the inlet and before sand filtration. Breakpoint chlorination was
done before granular activated carbon adsorption (GAC), followed by post chlorination, (Haarhoff J., van der Merwe B., 1995)
A change in treatment practice resulted in a change in chlorination with breakpoint chlorination for the first time after the GAC. Thereafter
secondary and post chlorination in order to maintain sufficient chlorine residual during distribution. This resulted in a huge saving in chlorine
consumption. The chlorine demand was reduced from 8 – 12 mg/l before the GAC to 0.5 – 2 mg/l after the GAC. The THM’s were also
drastically reduced.
2.
Change in coagulant
Traditionally, aluminium sulfate was used as primary coagulant at a dosage of 80 – 120 mg/l. Possible health effects from aluminium in
drinking water recognised internationally and the higher range of pH (8-9.4) caused from pollution in the catchment area by informal
settlements raised serious concern. Residual aluminium caused the formation of a gelatinous mass with residual dissolved organic matter
(NOM), which was traced into the drinking water distribution network. Experiments with ferric chloride and different blends of polymers
posed a cost-effective alternative. Since then ferric chloride is used at a dosage between 30 – 50 mg/l. Cost saving was achieved and the
problem of gelling successfully solved.
3.
Powdered activated carbon (PAC) as an alternative to granular activated carbon (GAC)
The use of GAC is a very expensive treatment option but is part of the integral treatment process in reclamation. Alternatives, such as PAC,
to reduce the organic load upstream of the GAC were tested in the laboratory and on full scale. The results were very promising both in cost
effectiveness and reducing the organic load. The removal of the PAC with settling posed a practical problem but could be accomplished with
dissolved air flotation (DAF). This alternative is kept as a backup in case production would have to be increased in an emergency beyond
the safe limits of the GAC design.
4. Ozone (O3), biological activated carbon (BAC) and GAC
Different pilot test studies were conducted between 1996 to 1998 to evaluate the use of ozone, BAC and GAC. Different carbon brands were
used in these studies. The results were very promising and resulted in the implementation of O3 – BAC – GAC in the new Goreangab
Reclamation Plant (NGRP), (Haarhoff J., van der Walt C.J., van der Merwe B.,1998)
5.
Filter-to-waste
A study was conducted to determine the presence of Giardia and Cryptosporidium in the raw water form the Goreangab Dam and the treated
effluent from the Gammams wastewater treatment plant. Due to the detection of these pathogens in the raw water, sand filter operation was
enhanced and fine-tuned. This resulted in the inclusion of a filter-to-waste facility on the sandfilters, where filtrate is wasted for a few minutes
after back washing. This has resulted in a higher degree of safety in the removal of these protozoan parasites, (Edwards D., 1999; Menge,
et. al. 2000).
6.
Ultra filtration (UF) membrane treatment
The higher levels of protozoan parasites in the raw water and the fact that chlorine is ineffective in inactivating Cryptosporidium oocysts
posed a potential problem. Alternative technology was required to ensure a physical barrier in the reclamation plant. Subsequently ultra
filtration (UF) was chosen to ensure the required log removal of pathogenic parasites.
Pilot testing started in 1996 and the efficiencies achieved in terms of through put looked very promising. In the course of two years 6
different membranes on 5 different pilot units were tested. The objective of removing protozoan parasites effectively (at least 5 log reduction)
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was achieved, which resulted in the inclusion of ultra filtration membranes in the NGRP.
7.
Enhanced coagulation and organics removal
Laboratory and full scale experiments were conducted to lower the concentration of NOM and other organic pollutants before GAC.
Hydrochloric acid (HCl) was used to lower the pH of the raw water effectively. This was done in combination with PAC and without PAC.
The results were as promising as reported in international literature. The disadvantage is the high corrosivity on the structures. It was
however decided to incorporate these options into the design of the NGRP, only to be used as a backup, should ozonation fail as a barrier for
the removal of organic substances.
8.
Change from lime to caustic soda (NaOH)
The use of brown lime prior to rapid sand filtration created two big problems in the operation of the OGRP. If the pH was not properly
controlled, it resulted in higher chlorine dosages to achieve the required Ct-product and the adsorption efficiency of the GAC was lowered.
Brown lime contained high levels of iron, manganese and calcium and a lot of other heavy metals in lower concentrations. These metals
were effectively removed by GAC, but competed for adsorption sites with the organic matter, which needed to be removed. The
regeneration efficiency and carbon lifetime between regeneration’s dropped, resulting in much higher treatment costs. A change to a better
quality lime was made and the dosing of lime before GAC was discontinued. The dosage of lime before or after the sand-filters to achieve
stable water caused a rise in final water turbidity, which was unacceptable. The use of caustic soda was investigated and replaced lime.
The objective of safe and stable water with low turbidity was achieved.
Wastewater treatment
1.
Upgrade of activated sludge plant (ASP)
In 1979 the ASP was commissioned. It was designed on the 5 stage Bardenpho process configuration for biological nutrient removal. An
inherent design mistake in the recycle rendered the process ineffective to remove phosphorus. Secondly the clarifiers were never able to
operate at full design capacity due to filamentous organism bulking. Treatment plant failure occurred regularly due to bulking during the first
ten years of operation. This was sorted out in 1989.
Design to increase the capacity of the Gammams treatment works started in 1991. The upgraded and extended ASP process was
commissioned in 1994. The unit was designed to operate at 3000 mg/l mixed liquor suspended solids (MLSS). The process was unstable in
terms of phosphate removal. De-nitrification was very easily upset by any changes in temperature, feed load or failure to provide constant
aeration.
2.
ASP optimisation
Full scale experiments were conducted on the ASP unit by varying the recycle rates, the aeration capacities and the concentration of the
MLSS. The ASP unit responded positively and is now operated at 4000 mg/l MLSS. Concentrations of < 1 mg/l ortho-PO4-P, < 0.2 mg/l
NH3-N and < 10 mg/l NO3-N are achieved more than 80% of the time.
In another experiment the MLSS were pushed up to 9000 mg/l. Both nitrification-de-nitrification and phosphorus removal was stable and not
impaired. COD, DOC and UV254 values of the effluent were extremely low.
3.
Primary process optimisation and biofilter operation
A new approach in operating the sludge withdrawal of the primary settling tanks and distributing it amongst the digesters resulted in better
sludge digestion and increased production of methane. The Jenbacher-engine, which is used to generate electrical power from the methane,
operates at almost maximum capacity. About 15% of the power needed by the whole sewage treatment plant is generated from methane.
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The biofilter operation was also enhanced by better instructions and supervision. Mechanical problems and “wrong” operational regimes
however restricted the unit to operate at optimal capacity. This will be addressed in the new upgrade.
4.
Phosphate removal with ferric chloride and disinfection of effluents
Experiments were conducted in 1991 and 1993 to remove phosphorus with ferric chloride from the biofilter effluents by dosing FeCl3 before
the humus tanks. In the laboratory good removals were established. Due to overloading of the humus tanks, this was not possible on full
scale.
Disinfection experiments with chlorine (Cl2) and hydrogen peroxide (H2O2) were also conducted on activated sludge effluent as well as
biofilter effluent. Chlorine proved very effective at low concentrations, but the hydrogen peroxide was ineffective. Both effluents are
effectively disinfected with chlorine, and the required levels of E coli can be reached for irrigation and discharge into the environment.
Catchment management
1.
Limnological study of Goreangab Dam.
The increase of informal settlements in the catchment area of the Goreangab Dam and the increase of sewer blockages resulted in a serious
deterioration of Dam water quality. Water sport activities on the Dam, like fishing, diving, wind-surfing, and sail boating were discontinued
due to serious health threats. At certain times of the year algae blooms or high ammonia levels rendered the water unsuitable for treatment
to drinking water.
A limnological study was initiated in 1995. Two Swedish students conducted a preliminary study. The recommendations of study were
however not completely followed up because of staff shortages and changes. Alternatives for implementing improvements were given in the
study report, which should be further investigated.
During the past two years blue-green algae/bacteria have been identified in the Goreangab Dam and toxins measured in very high
concentrations. It could be shown that the toxity is removed beyond detection limits in the reclamation plant. The toxins, thus are a hazard,
which need to be taken into consideration in design of the applied treatment technology.
Q8. Current research needs
that are related to water reuse
and prioritize if possible
Q9. Priority water reuse
research needs that can or
should be addressed through
the GWRC or other interna-
Future projects
In order to cope with the persistent water shortages and as a consequence of implementing water demand management, many alternatives
were identified, by which wastewater effluents could be re-used cheaper and safer. In 1996 a report was compiled listing all the projects of
importance to optimise the re-use of wastewater effluents. The projects were prioritised in order to use the manpower and finances optimally.
New priorities and options have emerged since then. The following projects will be conducted in the next couple of years. The use of
membrane bioreactors in effluent quality improvement, treatment of hazardous industrial effluents, Goreangab Dam catchment management
and limnology, chlorine deterioration and biofilm growth in potable water distribution systems and short-circuiting in reservoirs.
See point 4.
Suggestion 1
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tional research effort
In the book “Guidelines for Water Reuse – J Crook, DK Ammerman, DA Okun, RL Matthews; Camp Dresser & McKee Inc, 1992”, the authors
provide valuable information on re-use. However it leaves a reader wondering how to go about to implement a re-use scheme with regard to
minimum requirements that need to be fulfilled to successfully implement the project? It’s now 12 years later and a lot of results have been
published or at least re-use schemes have been implemented in the meantime. An international research team could list all the different case
studies in specific categories and then draw a conclusion of what the minimum requirements should/could be in each case.
Suggestion 2
In the article published by “Haarhoff J., van der Walt C.J., van der Merwe B. (1998). Process design considerations for the Windhoek Water
Reclamation Plant. WISA conference, Cape Town, South Africa”, the authors have made a valuable contribution on the barrier principle in
reclamation. Together with work done by the EPA and other international institutions with regard to the reliability of removal processes a chapter
can be spent on the different treatment processes and their reliability. (I am not suggesting to re-write all the design books published already.)
What I am suggesting is to list all the processes that have been successfully used in reclamation and how much log-removal can be contributed
to them (a. from research/application in drinking water field and b. from full scale applications in the reclamation field.)
Suggestion 3
Endocrine disruptors (+ pharmaceutical substances) and viruses are important health issues that need attention, especially the development of
reliable and affordable test methods.
Q10. Potable reuse issues
There are drinking water guidelines on national and international level, but there are no international guidelines for wastewater re-used/reclaimed
to drinking water level. Maybe consideration should be given to this subject.
Q11. Other relevant information in the field of reuse
See previous comments
Q12. Desalination issues
and/or research needs
If the salt load or balance in the closed loop of supplying reclaimed drinking water to a community/City gets too high what approach should be
taken to remove the salts. What do you do with the brine/salts if you are inland and not at the sea?
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GWRC Survey on Water Reuse
Water Research Commission (Africa)
Contact: Gerhard Offringa
[email protected]
Q5. Reports or publications,
including those that address
research needs for water
reuse
References to reports and publications on wastewater reuse in South Africa are listed as an appendix to this report. The main report which gives
some constraints/research needs, (as from page 33 onwards) is the document below (report embedded).
Q6. Key factors of success
that would support the future
development of water reuse
Public trust and acceptance
These are key to successful water reuse in Southern Africa. For these factors to be successful, requires technical process excellence, good
public awareness programs and a high standard of monitoring, which is also fully transparent to the general users.
Grobicki AMW and Cohen B (1998) Water Reclamation for Direct Re-use in Urban and Industrial Applications in South Africa, and its
Projected Impact Upon Water Demand. Water Research Commission Technical Report (KV118/99), Water Research Commission,
Pretoria.
Increased Government pressure on water demand management
Thus far in the region’s history, water demand management has not been enforced adequately. Water is generally under-priced and restrictions
only enforced under dire drought conditions. Lower fresh water consumption means lower income for the water utilities. Water reuse will,
therefore, only be enhanced should increased pressure be placed on water demand management. Both tighter policies on water restrictions, as
well as pricing water higher and closer to its “true” value, will stimulate the reuse of wastewater.
Technology excellence
The technology used in the purification of the wastewater should be efficient, trust-worthy and proven for the task required.
Cost of treatment
Cost (or pricing) of treatment should ideally be less expensive than the cost (or pricing) of fresh water supplies.
Availability of wastewater – both in quantity and quality
Wastewater of adequate quantities and acceptable quality should be available. Obnoxious industrial effluents should be separated from the
wastewater inflow to the treatment plant.
Efficient operations and monitoring
Consistently efficient plant operation and monitoring of product water quality should be guaranteed. High-skilled and well-trained personnel are
crucial. Water quality monitoring results should be consistently within risk management levels, Water quality monitoring methodology should be
fully transparent and results freely available to ensure the public acceptance of this water.
Q7. Ongoing, planned, and
completed research projects
Continuous research and development
R & D should continue at a high level to ensure ever-more cost-efficient treatment of water to ever higher quality standards. In this regard,
effectively addressing the issues listed under points 8. and 9. will ensure success.
Most of these projects were funded before the early eighties (see literature reviews and guidelines in the appendix). The latest survey of any help
is incorporated in the report by Grobicki, listed under 5. above.
Since wastewater reuse is not a national priority at the moment, no immediate further research projects aimed directly at wastewater reuse are
contemplated, but the research needs described in 8. below will be addressed should money become available or priorities change.
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Q8. Current research needs
that are related to water reuse
and prioritize if possible
• Identify the cities and towns with highest potential/need for wastewater reclamation, and the wastewater suppliers and potential users of
reclaimed water within these cities and towns. Opinion and user perceptions need to be determined and strategies suggested for the
facilitation of acceptance of the use of reclaimed water.
• Further development of analytical methods for water quality analyses. This should include improved accuracy and improved cost-efficiency.
• Ensuring microbiologically safe water for improved potability and lower distribution system microbiologically-induced corrosion. Removal or
killing of disinfectant-resistant organisms should be improved.
• Ensuring chemically safe water. Perform research on improving the efficiency of removal of priority chemicals.
• Perform research on the up-grading of existing wastewater treatment plants for supplying a reclamation plant. Include research on the costeffective integration of the wastewater and reclamation plants. Special attention should be given to the possible use of membrane bioreactors
and the potential for using a fully membrane-based plant (as from downstream of the primary settlers in the wastewater treatment plant).
Desalination should also be included as a final option.
• Compile guidelines for the process design of a reclamation plant, taking into account various possible feed water qualities and the various
possible treated water quality requirements.
• Compile risk-based guidelines for reclaimed water quality supplied for various purposes, as well as risk-based guidelines for the operation and
maintenance of reclamation plants.
• Perform research on alleviating the fouling of membranes used in the reclamation process.
Q9. Priority water reuse
research needs that can or
should be addressed through
the GWRC or other international research effort
Q10. Potable reuse issues
• Investigate the use of gray water and storm water run-off as possible sources for water reclamation.
The research needs listed above incorporate my needs as well.
See the points raised by the Windhoek, Namibia plant for the direct use to potable quality.
In addition, because of the long treated water distribution distances under hot temperature conditions, research is required on water quality
changes in the distribution system, as well as distribution system changes due to the water quality.
Q11. Other relevant information in the field of reuse
Q12. Desalination issues
and/or research needs
The rural populations in South Africa are very uneducated and illiterate.
Although regulatory needs are important, we first need to provide the technical basis for sound regulation. Although ways to influence peoples’
perceptions are to my mind the most important non-technical aspect to address, the technical aspects will provide the peace of mind of good and
reliable water. We should maybe split our research plan into technical and non-technical parts?
• Pre-treatment requirements
• Fouling/scaling
• Brine disposal
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APPENDIX B.2
Australia
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GWRC Survey on Water Reuse
CRC (Australia)
Contact: Tony Priestley
[email protected]
Q5. Reports or publications,
‘Water Recycling for Our Cities’ – Report to the Prime Minister’s Science, Engineering & Innovation Council, 11th Meeting, November 28, 2003.
including those that address
Downloadable Word and PDF files.
research needs for water
reuse
‘Water Recycling in Australia’ – Report undertaken by the Australian Academy of Technological Sciences and Engineering, 2004. Downloadable
from the ATSE website www.atse.org.au.
Q6. Key factors of success
that would support the future
development of water reuse
Q7. Ongoing, planned, and
completed research projects
The future development of water reuse in Australia depends critically on the following factors :
•
The development and nation wide application of uniform guidelines for water reuse. These guidelines must utilise the latest scientific and
technical knowledge relating to health risk estimation and management and the use of technologies for system design and operation
•
Reliable and affordable technologies must be available to implement different system designs for water reuse over a range of scales of
operation
•
Politically acceptable pricing policies for drinking and recycled water must be available to ensure efficient use of valuable water
resources
•
Communities need to be informed of alternative approaches to water recycling and accepting of new system designs before they are
implemented.
A uniform planning and institutional framework for water recycling needs to be developed and accepted nation wide in order to overcome barriers
imposed by inappropriate bureaucratic approval procedures.
Management of Third Pipe Systems Including Pathogen Regrowth
Industry parties have expressed concern that although the quality of treated effluent leaving the treatment plant may conform to recycled water
Class A standards, will it still conform to these standards at the point of use? As recycled water is increasingly being supplied to residential
properties through third pipe systems, a larger proportion of the population will be exposed to recycled water. Growth of opportunistic pathogens
in the recycled water distribution network is thus perceived to be a possible risk to human health.
This study aims to assess the risk to human health by examining biofilms in full scale, operating recycled water systems. Distribution systems
representing various climatic conditions and water classes will be examined through pipe cleaning techniques and through the use of biofilm
sampling devices. The results will be used to assess the risk to human health from pathogen regrowth in recycled water relative to potable water
distribution systems. Should pathogen regrowth be shown to increase significantly the risk to human health, the project will lead on to a second
phase involving laboratory simulation. Biofilm reactors will be used to identify the critical factors determining pathogen regrowth and ways of
controlling it.
Outcomes:
•
A better understanding of the risk to human health from recycled water and ways of reducing this risk.
•
Information which can be used in the development of National Recycled Water Guidelines.
Development of Useful Indicators and Rapid Detection Techniques for Monitoring Recycled Water.
Ensuring that reclaimed water is consistently of suitable microbiological quality is critical for it’s safe use and continued acceptance by the
community. Thermotolerant coliforms and E.coli are currently used as a measure of microbiological quality and are acknowledged to have many
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limitations, particularly the limitations of time and greater sensitivity to chlorination than many pathogenic viruses and protozoa. This project will
endeavour to establish whether there are other more suitable indicators of microbiological quality and whether these can be measured more.
Outcomes:
•
Reduction of risk to human health from improved turnaround time for testing of recycled water
•
Inclusion of the new indicator(s) in the proposed National Reclaimed Water Guidelines
Possible extension of the new indicator(s) to other water types.
•
Risk in the governance of water reuse: the case for the reuse of wastewater
While there is a general consensus that smarter water uses, including reuse and recycling, would improve urban water sustainability, many
issues in relation to these activities remain unresolved. In the pursuit of sustainability, water authorities at the local and metropolitan government
level in Australia have attempted to introduce innovative water and wastewater management practices, but the outcomes of many of these
initiatives have been mixed. One of the main issues complicating the implementation of water recycling has been the reaction of the public, but
there are other issues including the regulative framework, decision-making processes, funding sources, organisational cultures and broader
societal expectations which are important factors governing the outcomes of sustainable water initiatives. This interdisciplinary project explores
urban water management issues from an institutional perspective by examining the ways institutional capacity could be improved to promote the
development of sustainable urban water systems in Australia. The task of identifying avenues for strengthening institutions will be facilitated
through the collection and analysis of empirical data – including participant interviews, case reports and other forms of documentation – relating
to several water recycling initiatives in Australia
Sustainable Urban Water – Schemes & Technologies
Summary: The aim of this project is collect comprehensive data on a wide range of alternative water supply schemes & technologies and encode
such data into an interrogatable database. The database will provide information required by health and environmental regulators and the water
industry to enable comparison between alternate urban water systems. Such comparisons will assist in developing and implementing more
sustainable urban water management and the setting of risk based guidelines.
Industry Benefits: It is anticipated that the data will be able to be used for regulatory guidelines (eg. Reliability of technologies, monitoring
requirement, critical control points), validated operating data for future system design and will also identify technology and knowledge gaps.
Q8. Current research needs
that are related to water reuse
and prioritize if possible
The above projects were developed in direct response to the identified needs of the Australian water industry through a series of consultative
workshops. As such, they do reflect current research needs but are focused on a number of specific issues. The original Business Plan for
the Centre developed in 2000 identifies a list of broader issues that the industry sees as vital for future water system operations including
recycling. From this document and ongoing communications with the industry, the following research needs can be classed as high priority
for water recycling.
•
•
•
•
•
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The control of health risks from human pathogens throughout the full water urban cycle. This area includes not only understanding
the source and fate of pathogens, but also includes techniques for measurement, speciation, separation and inactivation
Micropollutants & endocrine disrupting chemicals – these pollutants will assume greater importance as the level of wastewater
reuse increases. A good knowledge base needs to be established to ensure the human and environmental safety of any reuse
scheme and particularly to allay public fears
The use of good social science skills to assess and manage community responses to water recycling proposals
The development of water treatment technologies which can be designed to operate reliably over a range of scales e.g. household
to small community scale
The design of third pipe systems to avoid or rapidly detect cross connections. The issue of cross connections is the Achilles Heel for
non-potable recycled water systems and designs and/or systems are needed to avoid this potentially catastrophic situation. The
research could be on system design or operation, including methods for rapid detection etc.
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Q9. Priority water reuse
research needs that can or
should be addressed through
the GWRC or other international research effort
Q10. Potable reuse issues
Q11. Other relevant information in the field of reuse
Q12. Desalination issues
and/or research needs
Many of the topics identified above are not unique to the Australian environment and results achieved through associated research projects
should be applicable to all countries represented in the GWRC. In particular, research on pathogens, micropollutants and small scale treatment
technologies should fall into this category. Some research on community attitudes and responses may be influenced by local cultural and social
attitudes, but even in this area international comparisons of community behaviour can be enlightening.
The need for reform of planning and institutional procedures which currently hinder alternative water supply schemes clearly must be addressed
at an individual national level. However, as with research on social attitudes, there is much to be gained by comparing and contrasting the various
national approaches to water supply planning and institutional oversight. Nothing opens the mind of a government bureaucrat more than the
realisation that many other countries do it ‘differently’!
Potable reuse is not being considered as a realistic option in Australia, chiefly because of the community’s strong aversion to such an idea. Most
of Australia’s cities get their water supplies from sources largely uncontaminated with human waste, which means that not even indirect potable
reuse is practiced. Adelaide may be the only exception here, but even in this case the level of sewage discharge to the Murray River is miniscule
as a percentage of the total flow.
Having said this, there may be situations arising in the future where potable reuse is a better option from both an environmental and economic
perspective. However, the barrier of public acceptance would still remain. Consequently, Australia would have an interest in any project
investigating public attitudes to potable reuse.
Most of these have been mentioned above. However, it may be worthwhile for those carrying out the State of the Science Review to interview (by
phone) a few key industry representatives in Australia to get a more accurate feel for the state of play in this country.
The key issues and research topics are :
•
Pretreatment options to minimize membrane fouling and flux decline
•
Lower cost membranes with reduced fouling potential and lower operating pressure requirements
•
Brine disposal – less of an issue for Australia where most of the population is near the sea, however, there are a number of communities
inland that have brackish ground water resources – and in these instances brine disposal will be a problem.
•
Optimal combinations of power generation and desalination system designs
•
Solar desalination for small communities
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GWRC Survey on Water Reuse
Water Services Association of Australia (Australia)
Contact: Ross Young
[email protected]
Q5. Reports or publications,
-ACT Wastewater Reuse for Irrigation Environment Protection Policy
including those that address
-NSW Guidelines for Urban Residential Use of Recycled WateReuse Association
research needs for water
-National Water Quality Management Strategy #14, Guidelines for Sewerage Systems: Use of Recycled WateReuse Association
reuse
-Framework for Management of Recycled Water Quality (revision of ARMCANZ/ ANZECC/ NHMRC, 2000)
-Queensland Guidelines for the Safe Use of Recycled Water (Public Consultation Draft)
-South Australian Recycled Water Guideline (ISBN 0 642 320217)
-Environmental Guidelines for the Use of Recycled Water in Tasmania
-Guidelines for Environmental Management Use of Recycled Water (ISBN 0 7306 7622 6)
Q6. Key factors of success
that would support the future
development of water reuse
The two key drivers for water reuse in Australia are:
1. Reducing impacts of treated effluent on receiving waters
2. Providing an alternative source of water for non-potable purposes so that augmentation of drinking water supplies can be delayed.
Depending on the main driver, the type of reuse scheme will vary greatly. For instance, if the driver is reducing the impacts of effluent on a
waterway, agricultural schemes are preferred as they offer the greatest opportunity to reuse significant quantities of treated effluent.
However, if delaying augmentation of existing supplies is a driver then third pipe use in new developments and provision of recycled water
for industrial/commercial purposes will be preferred.
The key factors of success to support water reuse in Australia are as follows:
1. The protection of public health and environmental objectives.
Rational: The protection of public health and the environment is an immutable objective, otherwise the potential for recycling will be set back
decades if there is a major public health or environmental issue.
2. Ensuring that recycled water can be provided at an economically viable price.
Rational: Obtaining a greater use of recycled water will be exceedingly difficult if it is priced at a great premium above alternative sources. To
ensure it can compete on price it will be necessary to use life cycle costing methodologies and delays to future water supply augmentations to
ensure the positive externalities of using recycled water are encapsulated in the financial assessments. There is also a need to ensure that
there is a balance between the standard of treatment required and the risks associated with the use of recycled water. For instance if an
excessively conservative view is taken and all recycled water has to be treated in a reverse osmosis treatment plant to ensure compliance with
water quality standards, this will increase the cost of the water significantly. On the other hand, a lower than required standard of treatment
could lead to public health issues.
3. Making sure that a triple bottom line analysis is conducted and that water resource outcomes are not pursued at the expense of other
objectives such as reducing greenhouse gas emissions.
Rational: Pursuing water reuse options without taking a holistic view of all of the externalities, both positive and negative, is likely to deliver
suboptimal outcomes for the community. It is important that a purely water resource criterion is not applied and that a broad approach is
adopted.
4. Ensuring the plumbing and building industries are adequately trained to minimize the risk of cross connections.
Rational: The installation of third pipe systems in new housing developments to allow recycled water to be used for toilet flushing and garden
watering represents a fundamentally different and new way of configuring water supply and plumbing networks. Without adequate training of
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plumbers and the development of consistent codes of practice, experience dictates that ‘if it can go wrong, it will’ and therefore the risk of
cross connections remains high.
5. Making sure that planning law, environmental regulation, public health regulation and the developer contributions levied by water utilities all
line up to support water reuse.
Rational: The existing regulatory planning framework is based on the ‘once through’ approach to the provision of water infrastructure. If reuse
is to be maximized it is essential that all of the approval authorities recognize the new paradigm we are operating in and amend their rules and
standards.
6. Making sure that the price charged is not under pricing the resource or if so expensive that it will preclude its use.
Rational: Pricing of recycled water is very important and there is evidence from the Rouse Hill development in Sydney that under pricing of
recycled water compared to the potable alternative has lead to excessive external water consumption and has prompted residence to fill
swimming pools with recycled water to save money. On the other hand we need to learn from the mistakes that have been made in pricing
service water and ensure recycled water is priced recognizing it will be a scarce resource at some stage in the future.
Q7. Ongoing, planned, and
completed research projects
7. Understanding the social aspects of water reuse, particularly monitoring people’s reaction to it in homes which have recycled water for toilet
flushing and garden watering.
Rational: Social research in Australia indicates that the community is willing to support recycled water for non-personal uses such as garden
watering and toilet flushing, but the closer to personal use of recycled water, the less people like it. Direct potable reuse is not on the agenda
in Australia and is unlikely to be in the medium term. We poorly understand the communities’ attitudes and perceptions to the vast array of
issues that the use of recycled water raises.
Just completed
Health Risk Assessment of Fire Fighting form Recycled Water Mains – WSAA Occasional Paper No. 11 – November 2004
In Progress
Principles for Pricing Recycled Water (will be completed in February 2005)
Development of a national code for third pipe systems (draft completed and final document will be completed by March 2005)
Development of a methodology for evaluating overall sustainability of water sensitive design and reuse schemes (will be completed March 2005)
A report on the best design criteria for small pumps including greenhouse gas emission calculations in water sensitive development (completed
April 2005)
Q8. Current research needs
that are related to water reuse
and prioritize if possible
WSAA is also involved in the process to develop National Guidelines for Recycled Water. This process has been broken into three areas, namely
the development of risk management framework, public health issues and environmental issues. The project was due to be completed by
December 2004 but it has been delayed and is scheduled for completion in June 2005. The public consultation paper on the guidelines will be
ready by the time we meet in April 2005.
The over riding research need in Australia in relation to recycled water relates to the public health aspects. This is due to the fact that we are
bringing recycled water into closer contact with people and we can ill-afford to make a mistake. The main public health research needs can be
summarized as follows:
1. Measuring and monitoring the reliability of treatment plants to ensure consistent performance particularly in relation to the removal of
pathogens, bacteria and viruses.
2. Monitoring the effectiveness of the removal of pathogens, bacteria and viruses in an ongoing manner.
3. Better understanding of the survival/regeneration of bugs in recycled water distribution systems.
4. Further work is required on exposure assessment to recycled water, particularly using Quantitative Microbial Risk Assessment methodology
using the DALY metric.
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Q9. Priority water reuse
research needs that can or
should be addressed through
the GWRC or other international research effort
Q10. Potable reuse issues
Q11. Other relevant information in the field of reuse
Q12. Desalination issues
and/or research needs
1. Topic of Concern – development of a predictive capability in assessing public health risks.
Project Description
Examine data from public health incidents/accidents to determine whether we can use this data to improve our predictive capability.
2. Topic of Concern – The adoption of appropriate water quality requirements for recycled water taking into account the need to protect public
health, but also ensuring that treatment costs are kept reasonable.
Project Description
Using QMRA methodology to undertake a review of risks associated with the use of recycled water and advise on the level of treatment for
various uses of recycled water.
3. Topic of Concern – There are no management systems in place for recycled water systems.
Project Description
Development of management systems dealing with all the risks associated with the use of recycled water to ensure that risks are minimized.
Potable reuse is not on the agenda in Australia and is not likely to be for a long time. Apart from strong community resistance to the concept,
there is no need for Australia to embark on this journey when we have many other water resource options we can pursue before we are forced
into considering potable reuse. Bear in mind the number of instances of direct potable reuse throughout the world are few and far between. (I
can only think of two examples)
The work that is being undertaken by KIWA in relation to personal care products and other inputs into the sewerage system should be referenced
strongly.
•
•
•
•
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The safe disposal of brine, particularly in near shore waters which are not oceans e.g. bays.
The ongoing risks of membrane failure.
Improving the low water recovery rates experienced in some plants, particularly in arid environments where water is a premium.
Solar desalination for small communities
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APPENDIX B.3
Europe
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GWRC Survey on Water Reuse
Aquarec (Europe)
Contact: Thomas Wintgens
[email protected]
Q5. Reports or publications,
[1]
including those that address
research needs for water
[2]
reuse
[3]
Q6. Key factors of success
that would support the future
development of water reuse
Q7. Ongoing, planned, and
completed research projects
R. Hochstrat, T. Wintgens, T. Melin, P. Jeffrey. Wastewater reclamation and reuse in Europe - a model-based potential estimation. In:
Proc. IWA 4th World Water Congress; Marrakech, Morocco, 19-24 September 2004.
T. Wintgens, T. Melin, A. Schäfer, S. Khan, M. Muston, D. Bixio and C. Thoeye. The role of membrane processes in municipal
wastewater reclamation and reuse. In proc. Intl Conf. on Membranes in Drinking and Industrial Water Production, L'Aquila, Italy;
November 15-17, 2004.
R. Hochstrat, T. Wintgens, T. Melin, P. Jeffrey. Assessing the European wastewater reclamation and reuse potential – a scenario
analysis. In: Proc. Integrated Concepts for Water Recycling; Wollongong, Australia, 14-17 February 2004.
Wastewater reuse presents a promising solution to the growing pressure on Europe’s water resources. However, wastewater reuse
implementation faces obstacles that include insufficient public acceptance, technical, economic and hygienic risks and further uncertainties
caused by a lack of awareness, accepted standards, guidelines and uniform European legislation. So far, there are no supra-national regulations
on water reuse in Europe and further development is slowed by lack of widely accepted standards e.g. in terms of required water quality,
treatment technology and distribution system design and operation. While guidelines for agricultural water reuse have been defined by the World
Health Organisation, and by different states such as the USA and many Mediterranean countries, a uniform solution for Europe could provide a
sound basis for further development of wastewater reclamation and reuse in many areas. European standards have to take a complex water
policy and management framework into account and have to balance the protection of water resources, economic and regional interests and
consumer-related safety standards.
-Integrated Concepts for Reuse of Upgraded Wastewater – AQUAREC (supported by European Commission in FP5, ongoing)
The general objective of the AQUAREC project is to provide knowledge for a rational strategy for municipal wastewater reclamation and reuse as
a major component of sustainable water management practices. The approach is interdisciplinary and broad, addressing issues of strategy,
management and technology. The project aims to define criteria to assess the appropriateness of wastewater reuse concepts in particular cases
and to identify the potential role of wastewater reuse in European water management. The project will provide guidance for end-users facing
decisions in the planning, implementation and operation of wastewater reuse schemes as well as for public institutions on various levels.
-Mitigation of Water Stress through new Approaches to Integrating Management, Technical, Economic and Institutional Instruments –
AQUASTRESS – Integrated Project supported by the European Commission in FP6 (planned)
TheAquaStress IP delivers enhanced interdisciplinary methodologies enabling actors at different levels of involvement and at different stages of
the planning process to mitigate water stress problems. This IP draws on both academic and practitioner skills to generate knowledge in
technological, operational management, policy, socio-economic, and environmental domains. Contributions come from 36 renowned
organizations, including SMEs, from 17 Countries.
-Investigation of Dead-end ultrafiltration for reuse of filter backwash water (completed)
Q8. Current research needs
that are related to water reuse
and prioritize if possible
Q9. Priority water reuse
research needs that can or
should be addressed through
the GWRC or other interna-
-Process combination of nanofiltration and powdered activated carbon for effluent reclamation (ongoing)
quality criteria for water reuse applications
new technologies for water application
behaviour of trace organics in water reclamation systems
integration of wastewater reuse in total water cycle management
I am not a GWRC representative but think that:
- the economy of water reuse projects has to be rethought in terms of a broader “water value” concept and the incorporation of externalities
- the water quality issues have to be connected through a quantitative risk assessment to environmental and human health risk issues
- treatment technology evaluations should be extended to emerging pathogens and contaminants issues
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tional research effort
Q10. Potable reuse issues
- participative processes have to be established in the context of water reuse planning
- in central Europe potable reuse is only practiced in one case (Wulpne/Torreele), the issues of unintended direct potable use through ground and
surface water augmentation by effluents have to be considered on a more “reuse linked” basis.
Q11. Other relevant information in the field of reuse
- community benefits of water reuse have to highlighted
- questions of technology development and adaptation in developing countries
- incorporation in total water cycle management has to be emphasised
Q12. Desalination issues
and/or research needs
- desalination becomes a viable option in several water stressed regions in Europe (including London, Southern Spain, Belgium)
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GWRC Survey on Water Reuse
KIWA (Europe)
Contact: L. Peter Wessels, MSc.
[email protected]
Q5. Reports or publications,
including those that address
research needs for water
reuse
Q6. Key factors of success
that would support the future
development of water reuse
Q7. Ongoing, planned, and
completed research projects
Kiwa is primarily focussed on water supply research. A major part of that research takes place on topics like membrane filtration, oxidation &
disinfection technology, (slow and rapid) zandfiltration,activated carbon filtration and ion exchange. We foresee however a stronger relation
between water supply and wast water treatment problems and research topics (think of EDC’s, medicines and other emerging substances, reuse
of waste water with MBR technology, etcetera)
Recently Kiwa also started with projects on reuse of waste water in industry and innovative MBR technologies, which go beyond current state of
the art.
In The Netherlands we have no shortage of fresh water, so reuse of WWTP effluent for drinking water purpose is not to be expected in the near
future. For industrial purposes reuse is a topic at the moment already. We think that reduction of costs (for MBR and other membrane
technologies) and solving the technical problems (fouling and concentrate of membranes) will boost reuse of WWTP effluent.
Membrane filtration
NOM fouling, biofouling, effects MF on water quality (afther growth distribution, retention of pesticides, NOM, EDC’s etcetera), concentrate
solutions for NF and RO.
Oxidation/disinfection
UV, UV-peroxide-GAC, Ozone-GAC, oxidation efficiency of pesticides, NOM, EDC’s etcetera)
Q8. Current research needs
that are related to water reuse
and prioritize if possible
Q9. Priority water reuse
research needs that can or
should be addressed through
the GWRC or other international research effort
Q10. Potable reuse issues
MBR
Innovative project started recently to lower the operation and investment costs and increase the water quality at the same time. At this moment no
information available.
Technological aspects already mentioned.
MBR technology (reducing costs, solving operational problems, quality increase)
MBR Post treatment (NF/RO, NOM/biofouling, concentrate solutions)
EDC’s, medicines, NDMA and other emerging compounds (comparison of different technologies to cope with these polutants)
UV disinfection (effectiveness)
Advanced oxidation (UV-peroxide, ozone, effectiveness, post treatment)
There is not (and there will not be in the future) a situation of water shortage.
Q11. Other relevant information in the field of reuse
- community benefits of water reuse have to highlighted
- questions of technology development and adaptation in developing countries
- incorporation in total water cycle management has to be emphasised
Q12. Desalination issues
and/or research needs
See remarks above. NF and RO will play a role in reuse of waste water. The answer to your question is: YES
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GWRC Survey on Water Reuse
STOWA (Europe)
Contact: Bert Palsma
[email protected]
Q5. Reports or publications,
including those that address
research needs for water
reuse
Compendium “WWTP-effluent and reuse” (in dutch; english summary)
STOWA report 200.14
Q6. Key factors of success
that would support the future
development of water reuse
Regulatory; water conservation / waste water treatment / surface water quality / ecology are separated in ways of money, organization and goals.
Q7. Ongoing, planned, and
completed research projects
Q8. Current research needs
that are related to water reuse
and prioritize if possible
Q9. Priority water reuse
research needs that can or
should be addressed through
the GWRC or other international research effort
Q10. Potable reuse issues
Development of a scheme for cost/benefit analyses of waste water reuse.
Q11. Other relevant information in the field of reuse
-
Organizational; see above.
-
-
Q12. Desalination issues
and/or research needs
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GWRC Survey on Water Reuse
UKWIR (Europe)
Contact: Alan Godfree
[email protected]
Q5. Reports or publications,
Water reuse: A review of current status in the UK Water Industry. UKWIR report 02/WR/28/1 (2002). Distribution of this report was restricted to
including those that address
UKWIR subscribers; it is available in electronic form by contacting the UKWIR office.
research needs for water
The joint report with AwwaRF and WRF will be produced in the near future
reuse
Q6. Key factors of success
that would support the future
development of water reuse
Q7. Ongoing, planned, and
completed research projects
a) Public acceptance – the first scheme in the UK that incorporated purposeful indirect reuse for drinking water supplies was met with negative
publicity in the media that led to public concern, but only at the final stage of consultation/implementation. The water utility concerned have since
recognised the need to address the psychological factors when formulating a communications plan. Redesigning the reuse scheme by
discharging treated wastewater to a watercourse prior to abstraction removed public concern. The UK has many examples of rivers used for
abstraction and discharge, in common with most developed, densely populated countries.
b) Regulatory – there are very few purposeful reuse schemes operating in the UK at the present time and as a consequence the regulators
(Environment Agency, Drinking Water Inspectorate, Ofwat) do not have policies in place that address their regulation. There is a need for
agreement by all regulators to a common policy or guidelines to be used when considering proposed reuse schemes.
a) Project WR/28 - A review of current status in the UK Water Industry (completed 2002). The objectives of the research study were to:
i) inform the UK water industry of the issues concerning effluent re-use including the implications for competition, and
ii) engage other stakeholders to develop a shared water industry position with particular regard to potential water resource planning for the
fourth Asset Management Plan (AMP4).
b) Project WR/29 - A protocol for developing water reuse criteria with reference to drinking water supplies (due to be completed Jan 2005). The
objectives of the research are to:
i) document existing standards for water reuse and their rationale/basis (public health and/or other parameters);
ii) identify merits and weakness of existing approaches;
iii) identify existing knowledge gaps that hinder development of rational and scientifically-supportable water reuse criteria, and
iv) develop a rationale for setting standards/guidelines based upon pathway/risk end point.
Q8. Current research needs
that are related to water reuse
and prioritize if possible
Q9. Priority water reuse
research needs that can or
should be addressed through
the GWRC or other interna-
In order:
a) common regulatory policy
b) identification of factors that lead to successful implementation of reuse schemes, particularly public acceptability
c) environmental impacts of desalination
Topic areas:
a) public acceptance
b) ability of treatment processes to remove/inactivate endocrine disrupting substances, pharmaceutical residues, viruses
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tional research effort
Q10. Potable reuse issues
c) emerging contaminants
d) food safety aspects of using reclaimed water for crop irrigation
e) sustainability of desalination (for potable supply)
a) public acceptance
b) food safety aspects of using reclaimed water for crop irrigation
Q11. Other relevant information in the field of reuse
a) sustainability of desalination (for potable supply)
b) understanding issues/criteria that contribute to public acceptability
Q12. Desalination issues
and/or research needs
a) environmental impacts of desalination
b) operating costs
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GWRC Survey on Water Reuse
Veolia (Europe)
Contact: Bruce Durham
[email protected]
Q5. Reports or publications,
Why is water reuse so important to the European Union? Ref EU1/2-04-WR21(6)
including those that address
Final submitted to Board for approval in November 04
research needs for water
reuse
International water reuse benefits and issues survey ref EU1/2-040WR22(1)
Water reuse in EUREAU countries: with emphasis on criteria used. EU1/2-03-WR-18F
Document being updated in December 04
Q6. Key factors of success
that would support the future
development of water reuse
A detailed understanding at all levels of integrated water cycle management and the benefits that water reuse already provide and the
opportunities and risks for the future.
Agreement in the meaning of the word “appropriate” in European Urban Wastewater Directive that “treated wastewater should be reused
whenever appropriate”
Approved institutional framework to allow appropriate reuse projects to be implemented based on quality, economic, environmental and social
benefits that can be clearly measured for the alternative solutions
Local flagship project to build trust and prove the benefits
Open and honest communication about water reuse and :
the real anthropogenic water cycle
the confusion between desalination technology for reuse projects and seawater desalination
the fragmentation of the water industry into potable and wastewater silos as if they are different waters
Q7. Ongoing, planned, and
completed research projects
Q8. Current research needs
that are related to water reuse
and prioritize if possible
Ongoing
www.aquarec.org
www.kompetenz-wasser.de nasri
Economic externalities to clearly measure the benefit of reuse projects compared to the alternatives
Epidemiological evidence of the impact of indirect potable reuse on health
The economic benefit of water reuse to the local community with regards to food production, industry, employment, water resource availability,
urban parks, land revaluation, flood prevention and tourism
Development of sustainable systems using non fossil fuels
Reuse as a solution to climate change (energy consumption, droughts, floods, increase seawater ingress due to rising sea levels)
Water reuse – water & nutrient reuse for optimization of food production
Best practice for Golf irrigation
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New city development and the benefits of integrated water cycle management strategies
How can water reuse and unused power generation capacity provide energy storage during off peak periods?
How much does recycled water cost to produce in dollars and energy and what do operators around the world sell it for and why that price?
Q9. Priority water reuse
research needs that can or
should be addressed through
the GWRC or other international research effort
Q10. Potable reuse issues
Same As 8
Q11. Other relevant information in the field of reuse
-Barriers
-Ignorance of the water cycle and where reuse provides a benefit
-Lack of quality guidelines, best practice, water ownership issues, financial incentives
-Stake holder participation in integrated water cycle management issues
-Confusion about what is reuse and what is desalination?
-Confusion about different markets and technologies
Q12. Desalination issues
and/or research needs
Lack of understanding of the term potable reuse (except by an enlightened few) due to a lack of understanding of the real water cycle
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APPENDIX B.4
United States
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GWRC Survey on Water Reuse
Awwa Research Foundation (USA)
Contact: Jennifer Warner
[email protected]
Q5. Reports or publications,
including those that address
research needs for water
reuse
Q6. Key factors of success
that would support the future
development of water reuse
A list of ongoing, planned, and completed research projects related to reuse, which have been funded or co-funded by AwwaRF, is listed
below under Item 7. Those available reports which contain an overview of reuse and/or identify research needs are identified in the list.
The identification of key users of reclaimed water (e.g., industry vs. municipal) and their respective water quality requirements would be a key
factor of success.
A clear understanding of the known public health impacts of reclaimed water quality for municipal use (direct and indirect) is necessary to
overcome the psychological barriers.
Q7. Ongoing, planned, and
completed research projects
Discourage Jay Leno or other prominent public figures from expressing ignorance on the topic of reuse (i.e., the “toilet to tap” phenomenon).
Really this means public education is a key factor of success.
AwwaRF funded or co-funded projects directly related to reuse are listed below in chronological order of funding or completion, along with
information to obtain the available reports (in print or electronically). If a project is listed as completed, but not yet published, a prepublication version of the report can be made available for the purposes of generating the “State of the Science” report.
Also, AwwaRF is currently funding several research projects related to endocrine disrupting and pharmaceutically-active compounds in raw and
finished drinking water. Also, projects developing methodologies to monitor EDCs and PhACs in water are underway. If there is interest in these
projects, please let me know.
Ongoing Research Projects
•
“Membrane Treatment of Waste Filter Washwater for Direct Reuse” AwwaRF Project 2568 – This project is investigating the
feasibility of using membrane technology to treat filter backwash water for direct reuse. The project includes a three-phase approach
consisting of planning and research tasks in Phase I; a tiered program of pilot-scale testing in Phase II; complemented by feasibility and
cost analyses in Phase III. The project is being conducted in conjunction with planning for a future filtration plant for the New York City
Catskill and Delaware supplies. The project has experienced many delays with respect to siting issues and other construction conflicts
and it is unclear when the project will be finished.
•
“Dissolved Organic Nitrogen (DON) in Drinking Water and Reclaimed Wastewater” AwwaRF Project 2900 – This research is
determining DON occurrence in raw and finished drinking waters and reclaimed wastewaters. The final report will provide information on
DON’s chemical characteristics and reactivity toward metal hydroxides and oxidants, and on its role in THM and NDMA formation.
Research is nearing completion and a final report is anticipated in 2005.
•
“Understanding Public Concerns and Developing Tools to Assist Local Officials in Planning Successful Potable Reuse
Projects” AwwaRF Project 2919 – This project is developing a better understanding of public concerns and potential opposition to
indirect potable reuse. An array of approaches (i.e., a toolkit) is being developed for utilities to use in working with stakeholders in order
to improve planning and implementation of reuse projects. Guidance will be provided on using the toolkit and on defining and targeting
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the resources needed for success. A Web site is being developed that can be accessed by pubic officials as they proceed with their
reuse projects. Phase I was completed in 2004. Phases II and III are to be completed in 2005. (WRF co-funding)
•
“Contribution of Wastewater to DBP Formation” AwwaRF Project 2948 – This project is identifying the types and quantities of
wastewater-derived DBPs in various types of municipal drinking water sources influenced by municipal wastewater. The study will also
characterize the DBP precursor material and resulting types and quantities of DBPs expected in the finished water from source waters
containing wastewater. Control and treatment strategies are being identified that can be used in both wastewater and water treatment to
reduce or eliminate precursors and wastewater-derived DBPs, and strategies will be suggested that best balance societal benefits with
cost. Research will be complete in late 2005. (USEPA co-funding)
•
“Water Quality Changes (or Impacts) Associated with Aquifer Storage and Recovery” AwwaRF Project 2974 – This project
essentially builds on the knowledge gained in Project 2618 “Water Quality IMPROVEMENTS during Aquifer Storage and Recovery”
(listed below as a completed project), and expands the scope to examine the “impacts” to water quality during ASR. The project has
only recently begun (December 2004) and research will be complete in 2006. (CSIRO co-funding)
•
“A Novel Approach to Seawater Desalination Using Dual-Staged Nanofiltration Process” AwwaRF Project 3005 – This project is
evaluating dual-staged nanofiltration as an alternative to traditional reverse osmosis (RO) membranes for seawater desalination. This
process would have the advantage of operating at lower pressures and may therefore be considerably more economical. However, a
dual-staged nanofiltration system for seawater desalination is a new concept, and operational and design parameters are not currently
available. Research will be complete in 2005.
•
“Zero Liquid Discharge and Volume Minimization for Inland Desalination” AwwaRF Project 3010 – The objective of the research is
to develop technologies that reduce the treatment costs for inland desalination with zero liquid discharge. The technical approach
involves alternating applications of reverse osmosis with precipitation processes designed to remove the least soluble salts under
conditions of controlled mixing, salt seeding, chemical addition, residence time, temperature, and pH. Five water sources will be benchtested and a ZLD process will be developed for each. One of the water sources will undergo extensive pilot testing. (CEC co-funding)
•
“Comparison of Nanofiltration and Reverse Osmosis in Terms of Water Quality and Operations Performance for Treating
Recycled Water” AwwaRF Project 3012 – This project will evaluate the feasibility of nanofiltration (NF) and ultra-low-pressure reverse
osmosis (ULPRO) membranes for rejecting total organic carbon, total nitrogen, and unregulated trace organic compounds under a range
of experimental conditions at the laboratory-, pilot-, and full-scale to produce water suitable to augment drinking water supplies.
Guidance will be developed for utilities to select membranes and predict solute rejection during NF-ULPRO membrane treatment.
Research will be complete in late 2005. (WRF co-funding)
•
“Desalination Product Water Recovery and Concentrate Volume Minimization” AwwaRF Project 3030 – This is a phased research
project with an objective to develop an innovative approach to advance desalination technology for product water recovery and
concentrate volume minimization. If the results from Phase I demonstrate the technology has potential to improve desalination recovery
thereby reducing the concentrate volume, then a bench-scale investigation will follow. AwwaRF and its Project Advisory Committee will
evaluate the Phase I results and determine whether to continue with Phase II. Research began in late 2004 and is anticipated to be
complete in 2006.
•
“Design, Operation and Maintenance Considerations for Sustainable Underground Storage Facilities” AwwaRF Project 3034 –
The project will identify and evaluate technical variables that are critical to the successful design, long-term operation, and maintenance
of sustainable underground storage (SUS) facilities. A contractor has only recently been selected (November 2004), and research
should begin in early 2005.
Planned Research Projects
•
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Compounds, and Personal Care Products in Drinking Water” AwwaRF Project 3033 – This project will synthesize existing
knowledge on endocrine disrupting compounds (EDCs), pharmaceutically active compounds (PhACs), and personal care products
(PCPs) in drinking water supplies. The research will also examine what is currently known about health effects, analysis, occurrence,
and behavior in drinking water treatment processes for this broad range of compounds.
•
“Potential and Pitfalls for Sustainable Underground Storage of Recoverable Water” AwwaRF Project 3043 – This study will
provide an overview of some of the research needs and priorities concerning sustainable underground storage technology
and implementation. The project will also assess geological, geochemical, biological, engineering, and institutional factors that may
contribute to good or poor performance of such projects. The project is planned for 2005. (NRC co-funding)
•
“Inland Concentrate Treatment Strategies for Water Reclamation Systems” AwwaRF Project 3096 – This research project will
identify and develop methods to manage brine streams from water reclamation systems (including agricultural drainage) so that the
water may be recovered for potable or industrial purposes while the salts are converted into solid by-products. The project will also
determine the optimum combination of membrane, thermal, and solid-liquid separation processes for different brine solutions, and
develop a computer model for optimizing unit processes for different water qualities. The research will provide a bench-scale testing
protocol for simulating different brine concentration strategies. This project is planned for 2005.
Completed Research Projects
•
Issues in Potable Reuse: The Viability of Augmenting Drinking Water Supplies with Reclaimed Water (ISBN 0-309-06416-3,
NAS 1998) – This report gives technical guidance regarding the use of treated municipal wastewater as a potable water source, and
provides regulators and utilities with guidance to assess the feasibility and desirability of potable reuse projects as a means of
supplementing water supplies. The report includes an overview of reuse and recommendations for future research. This report is
available from the National Academy Press (telephone: 800-624-6242; NAP Web site). (NAS co-funding)
•
Pilot Studies to Design and Model Soil Aquifer Treatment Systems (AwwaRF and AWWA 1998) – This study focused on the soil
and water interface of soil aquifer treatment (SAT). From a design standpoint, the soil and water interface is the portion of an SAT
system that is most significantly influenced by wet and dry cycle time, effluent pretreatment, soil type, and pond depth. An entire SAT
system also includes treatment in the vadose zone and the aquifer. The characteristics of the vadose zone and aquifer are important for
site selection, but are not strongly influenced by aboveground operations. Design variables for SAT would include the distance to
recovery wells and the control of groundwater mounding; however, criteria for design of these variables have not been developed. The
report is available in print only from the AwwaRF Web site.
•
Soil Aquifer Treatment for Sustainable Water Reuse (AwwaRF and AWWA 2001) – The study found that effluent pretreatment did
not affect final soil-aquifer treatment (SAT) product water with respect to organic carbon concentrations. A watershed approach may be
used to predict SAT product water quality. Additionally, removal of organics occurs under saturated anoxic conditions, and a vadose
zone is not necessary for an SAT system. If nitrogen removal is desired during SAT, nitrogen must be applied in a reduced form, and a
vadose zone combined with soils that can exchange ammonium ions is required. It was also noted that the distribution of disinfection
by-products produced during chlorination of SAT product water is affected by elevated bromide concentrations in reclaimed water. The
report is available to in print only from the AwwaRF Web site. (USEPA co-funding)
•
Nonthermal Technologies for Salinity Removal (AwwaRF 2001) – This study evaluated reverse osmosis (RO) with ultra-low-pressure
membranes to desalinate Colorado River water using the following pretreatment processes: microfiltration, conventional treatment, and
conventional treatment with ozone and biological filtration. The project also evaluated capacitive deionization with carbon aerogel
electrodes at the bench-scale to determine its efficacy as a desalting technology. Research needs are identified. The report is
available in print only from the AwwaRF Web site.
•
Industrial Water Quality Requirements for Reclaimed Water (AwwaRF 2004) – This report summarizes water quality requirements
for industrial year-round uses of reclaimed water (excluding irrigation, groundwater recharge [where much is otherwise documented],
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and pharmaceutical/microchip industries [where water quality requirements are too stringent]). The report also discusses the viewpoints
of 12 suppliers (utilities), 43 industrial users (customers), and seven regulators (state agencies). The report is available in print and
electronic format from the AwwaRF Web site or the IWA Publishing Web site. (WRF co-funding)
•
“Water Quality Improvements during Aquifer Storage and Recovery” AwwaRF Project 2618 – This report will enable utilities to
evaluate the ability of an aquifer to improve water quality and will provide scientific support for more pragmatic water-injection
regulations. Ultimately, utilities with limited source water or treatment capacity might be able to plan for other potential supplies of ASR
water, such as stormwater, other high-quality raw water, or partially-treated wastewater. The results of this study will also help utilities
predict water quality improvements that could occur during ASR and optimize their treatment accordingly. The report is currently in
publication and will be available in early 2005.
•
“Factors Affecting the Formation of N-Nitrosodimethylamine (NDMA) in Water and Occurrence” AwwaRF Project 2678 – This
project determined the levels of n-nitrosodimethylamine (NDMA) in drinking water, recycled water, and wastewater through an
occurrence survey of potentially vulnerable raw and treated water supplies. The research established whether NDMA is a disinfection
by-product and the possible water quality factors (i.e., precursors, pH, chlorination species, natural organic matter [NOM]) affecting its
formation in drinking water and wastewater treatment plants. The fate and transport of NDMA was characterized in both surface water
and groundwater in order to determine what levels of NDMA are likely to occur in groundwater given the initial concentration in treated
wastewater effluent. Research is complete and the final report is being prepared for publication, and it’s anticipated to be available in
2005. (WERF co-funding)
•
“A Novel Approach for Understanding the Recharge Mechanisms to the Memphis Aquifer” AwwaRF Project 2700 – This research
developed a procedure for quantitatively assessing the magnitude of recharge through openings in the clay layer that confines much of
the Memphis Aquifer. An example is provided that could be used by other utilities for planning or development of monitoring systems in
the same region and similar geological settings. The research is completed and the final report is being prepared for publication. The
report is anticipated in 2005.
•
“Characterizing Microbial Water Quality in Reclaimed Water Distribution Systems” AwwaRF Project 2703 – Characterizes the
extent and nature of problems of water quality deterioration as it relates to microbial fouling and regrowth in reclaimed distribution
systems. Determines the operational procedures to best meet the needs of utilities for operation of reclaimed water storage/distribution
systems and provides guidelines for the operation and maintenance of these systems. This report will provides an overview of reuse,
a summary of existing research, and a U.S. regulatory review. Research is complete and the final report is being prepared for
publication. The report is anticipated in 2005. (WRF co-funding)
•
“Characterizing Salinity Contributions in Sewer Collection and Reclaimed Water Distribution Systems to Develop Salinity
Management Strategies” AwwaRF Project 2744 – This project developed and tested a protocol for characterizing commercial,
industrial, and residential salinity contributions in both sewer collection and reclaimed water distribution systems. Guidelines were also
developed for identifying economic impacts of implementing salinity management practices to customer requirements and regulatory
standards. Research is complete, the final report is being prepared for publication, and it’s anticipated to be available in 2005. (WRF
co-funding)
•
Q8. Current research needs
that are related to water reuse
and prioritize if possible
“Protocol for Developing Water Reuse Criteria with Reference to Drinking Water Supplies” AwwaRF Project 2968 – This project
documented existing domestic and international standards and their rationale/basis (i.e., public health and/or other parameters), defined
merits and weaknesses of existing approaches, identified gaps in existing knowledge, and developed a rationale for setting
standards/guidelines based upon pathway/risk end point. Research is complete, the final report is being prepared for publication, and it
is anticipated to be available in early 2005. Also, a technology transfer Webcast is being planned for early 2005. (WRF/UKWIR cofunding)
Following are ideas brought to our attention from subscribers in the recent research planning cycle. We have not yet begun identifying and
prioritizing research needs for 2005, but will look into these ideas in the coming months.
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“As an alternative approach to centralized water recycling facilities that collect, treat, and redistribute reclaimed water to customers over broad
geographic areas, satellite water recycling centers are beginning to provide cost-effective, localized, reclaimed water use opportunities. Satellite
water recycling centers (sometimes called scalping plants) treat the liquid wastewater phase and convey the residual solids to the centralized
wastewater treatment plants while providing the treated, reclaimed water for localized applications. This approach is developing at a more rapid
rate in recent years by small and large utilities alike. More technical study of this technique now appears warranted from the standpoints of
collection system impacts, concentrated waste stream treatment impacts at the centralized plants, and for the potential satellite operational and
customer impacts that might be associated with this reuse application. This information would be very valuable for reuse program planning and to
help establish proper regulatory guidelines for these facilities that often aren't currently addressed on a state-by-state basis as this approach
continues to emerge as viable reuse technology.”
“Risk assessment should be tied to regulatory efforts in reuse. Currently, no water reuse criteria in the U.S. are based on strict risk assessment
methodology. Including risk assessment as one of the tools used to develop scientifically-based criteria would result in more rational and
defensible criteria and increase pubic acceptance of such criteria.”
Q9. Priority water reuse
research needs that can or
should be addressed through
the GWRC or other international research effort
Q10. Potable reuse issues
“There is a need to investigate and identify the long term impacts of reused water on commercial and residential landscape, as reused water
continues to meet the demands of water utility customers. For example, Denver Water's future supply is projected to be 30% reused water, and
they are being told that reused water is killing the conifers. What are the soil concentration build-ups that result from reusing water to irrigate?”
I understand much research is being accomplished with regard to concentrate streams from reclaimed and desalination treatment processes,
however there is no doubt much left to be researched and understood. Beneficial uses (or reuse, including marketing) of concentrate need to be
identified and researched.
Regarding desal: As discussed briefly in Item 12, blending impacts of reclaimed water and conventionally-treated water on public health and
distribution system infrastructure is an important research need in my opinion.
Public perception is a major hurdle in the United States to widespread adoption of reuse for either indirect or direct purposes. Education of the
public is a tricky and challenging task, exacerbated by regional concerns (e.g., water availability, political atmosphere, etc.) and regulatory
concerns (e.g., CWA vs. SDWA). The State of the Science report should include this as a special consideration for the North American
application.
Q11. Other relevant information in the field of reuse
Q12. Desalination issues
and/or research needs
Technologies used to treat water for reuse purposes (including desalination) are aggressive and thus, can result in a “de-mineralized” or
otherwise, “ultra-pure” product water. These product waters need to be blended with other conventionally treated waters if they are to be used for
potable purposes. Not much is currently known about the impacts of this blended water on distribution system infrastructure or public health.
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GWRC Survey on Water Reuse
Water Environment Research Foundation (USA)
Contact: Jami Montgomery
[email protected]
Q5. Reports or publications,
including those that address
research needs for water
reuse
Water Reuse, #D42004, The planned reuse of municipal wastewater has been practiced throughout the world for many years. Information gaps
and unresolved issues persist despite the abundance of published material on the topic. For this report, the project team critically reviewed
existing information and valid scientific data relative to water reclamation and reuse, presented 71 potential research topics, and identified six
research projects that would be the most useful in advancing water reclamation and reuse of municipal wastewater. Published by WERF. 1994.
(Hardcopy only)
Management Practices for Nonpotable Water Reuse, #D13005
This report is a review of nonpotable reuse planning and management experiences. The study comprises an extensive literature review, a
management survey encompassing 65 projects in the U.S. and other countries, and the inclusion of thematic case examples. The resulting
report addresses a spectrum of topics, including economic, regulatory, management, planning, and public outreach. Published by WERF. 2001.
(PDF available)
Q6. Key factors of success
that would support the future
development of water reuse
Water Reuse: Understanding Public Perception and Participation, #00PUM1
Water reuse initiatives in the United States have faced significant public opposition in recent years. In this report, a project team of social
scientists, engineers, and water utility managers provide guidance to help water professionals communicate with the public about water reuse
issues and other controversial issues. The report details a framework of five principles that should underlie all communication, as well as
methods to analyze and tailor outreach efforts to a particular community. Published by the Water Environment Research Foundation. 2004.
(PDF available)
Technical: While non-potable reuse is growing in the US, questions remain about the potential public and environmental health impacts from
microbial pathogens and chemical contaminants found in treated wastewater.
Economic: Tertiary treatment technologies need to become more cost effective and easier to use so as to promote more widespread usage at
wastewater treatment plants.
Q7. Ongoing, planned, and
completed research projects
Sociological: For reuse to be successful in the U.S. it needs to be considered in the context of managing the total water resource needs of a
community. As the US population grows, high-quality source waters are becoming increasingly rare and many communities are already using
water sources that are significantly impacted by treated wastewater. Water reuse needs to reach a point where it can be considered along with
other watershed management options.
• Water Reuse Assessment (92-WRE-1)
Evaluates existing technologies, examines planning and management issues, and reviews standards and guidelines for a wide variety of water
reuse applications. (Completed)
•
Issues in Potable Reuse (96-HHE-1-CO)
This NRC study assessed the public health implications of using reclaimed water as a component of the potable water supply. (Completed)
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Nonpotable Water Reuse Management Practices (97-IRM-6)
Will survey and report experiences of reuse programs. Will document models for planning and management, assess costs of reclamation, and
the financing used to develop and operate reclaimed water systems. Will report various rate structures, and legal and liability issues, and
define the level of treatment required for different uses. Can help new planning efforts to better address public perception issues and
effectively involve stakeholders. (Completed)
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Feasibility and Application of Membrane Bioreactor Technology for Water Reclamation (98-CTS-5)
Will explore the feasibility and application of membrane bioreactor (MBR) technology to reduce costs and increase practicality of water
reclamation for various uses. Will be a pilot study at the San Diego North City Water Reclamation Plant. Report will summarize the advantages
and limitations of MBR process, and address the potential of MBRs for water repurification, configuration problems for full-scale development,
and regulatory compliance and preliminary cost estimates. (Completed)
A Comparative Study of the Physiochemical Properties and Filtration of Several Human and Bacteria Viruses: Implications for
Groundwater Recharge (98-PUM-1CO)
Will characterize the surface electrostatic properties and filtration behavior of viruses. Will elucidate the scientific principles that regulate
virus filtration in groundwater and provide support for the selection of bacteriophage as indicators of waterborne disease. (Completed)
Impact of Surface Storage on Reclaimed Water: Seasonal and Long Term (99-PUM-4)
Will provide understanding of which water quality computer modeling tools will effectively address water quality issues for seasonal and longterm surface storage of reclaimed water. Information on use and applicability of models to determine reclaimed water storage design, water
quality, and operation for specific storage facilities will maximize the effective use of existing resources for reclaimed water applications, and
allow for improvement of design and management of facilities. (Completed)
Water Reuse: Understanding Public Perception and Participation (00-PUM-1T)
Will provide guidance for water resource professionals to successfully incorporate stakeholder priorities in water reclamation programs. Will
help members of the water industry address the social & political complexity of adopting potable and nonpotable water reuse and recycling as
part of a sustainable community strategy. (Completed)
Evaluation of Microbial Risk Assessment Techniques and Applications in Water Reclamation (00-PUM-3)
Will evaluate existing microbial risk assessment models for nonpotable uses of reclaimed water and will enhance one of the models. Will help
provide a basis for future regulations and rulemaking for nonpotable use of reclaimed water. (Completed)
Strategies for Sustainable Water Resource Management (00-WSM-6)
Sustainable management of a resource can allow its use to meet current needs yet not diminish the resource’s potential use for future
generations. This project will develop a comprehensive, integrative framework for developing and implementing sustainable water resource
management plans that will set the national context for practioners at the local and regional levels. (2003)
Online Toxicology Methods for Evaluating Potential Chemical Risks Associated with Potable Reuse – Workshop (01-HHE-4)
Workshop will evaluate state-of-the-art toxicologic techniques for on-line monitoring of reclaimed water quality. Will determine the most
appropriate approach to use for the development of an effective online method. (Completed)
Online Toxicology Methods for Evaluating Potential Chemical Risks Associated with Potable Reuse – Project (01-HHE-4A)
Following the workshop, the selected method will be developed, evaluated, and validated for its effectiveness as an appropriate monitoring
tool for reclaimed water. This method will provide a scientifically sound tool to monitor the water quality of reclaimed water and thus advance
its acceptability by the regulatory and user communities. (2005)
The Use of Bioassays and Chemical Measurements to Assess the Removal of Endocrine Disrupting Compounds in Water
Reclamation Systems (01-HHE-20T)
Will apply endocrine disruption bioassays and chemical analyses to evaluate water reclamation treatment processes that will be employed to
prevent endocrine disruption in the aquatic environment. (2005)
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Evaluation and Testing of Bioassays for Pharmaceutics in Reclaimed Water (01-HHE-21T)
Will validate the use of bioassays for detecting and quantifying one or more major classes of pharmaceutical contaminants. This approach will
serve as a model for developing assays for other classes of pharmaceutics that have potential health risks for aquatic ecosystems and
humans. (2004)
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Contributions of Household Chemicals to Sewage and their Relevance to Municipal Wastewater Systems and the Environment (03CTS-21-UR)
Will select a short list of High Volume Production (HVP) chemicals for analysis of removal efficiencies through different wastewater treatment
processes. (2004)
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Fate of Pharmaceuticals and Personal Care Products through Wastewater Treatment Processes (03-CTS-22-UR)
Will assess the fate of PCPPs through conventional secondary and tertiary wastewater treatment facilities. (2005)
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Long-term Study on Landscape Irrigation using Household Graywater (03-CTS-18CO)– Will provide quantitative evidence regarding
the safety of household greater reuse for landscape irrigation, focusing on assessing consumer product usage and disposal recommendations
in graywater reuse systems. This first project will be a workshop which will be followed by field evaluation. (2005)
• Development of Indicators and Surrogates for Chemical Contaminant Removal during Wastewater Treatment and Reclamation (04HHE-1CO)
Will develop a list of potential indicators and/or surrogates and to validate their suitability of wastewater and recycled water treatment methods
for various water reuse applications and beneficial uses of receiving waters. (2006)
Q8. Current research needs
that are related to water reuse
and prioritize if possible
Q9. Priority water reuse
research needs that can or
should be addressed through
the GWRC or other international research effort
Q10. Potable reuse issues
(loosely prioritized)
• Fate of anthropogenic chemicals and pathogens in reuse applications
• Efficacy of existing and new reclamation treatment processes
• Removal and/or inactivation of pathogens during treatment
• Evaluation of reliability issues for membranes and other processes
• Evaluation of advanced oxidation processes and biological processes to produce biologically stable reclaimed water
• Whole effluent toxicity measurements for reuse applications
• Public participation
Topics for GWRC (not prioritized):
• Fate and transport of chemicals and pathogens following irrigation
• Public health implications for potable reuse
• Improved treatment technologies
• Effects of storage of water
• Removal and inactivation of potential pathogens
• What are the appropriate indicators for pathogens
While there are successful indirect potable and non-potable reuse projects around the country there still remain significant barriers to public
acceptance of direct potable reuse. Much of this resistance is based on the persistent scientific uncertainty that remains about the level of
removal of pathogens and trace organic compounds. WERF is not in favor of having the GWRC address issues such as public acceptance or
participation in regards to reuse because we believe there are cultural barriers to such research being translatable across our various member
countries.
Q11. Other relevant information in the field of reuse
Q12. Desalination issues
and/or research needs
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GWRC Survey on Water Reuse
WateReuse Foundation (USA)
Contact: Jeff Mosher
[email protected]
Q5. Reports or publications,
Reports by the Federal and State Governments:
including those that address
research needs for water
• Guidelines for Water Reuse, U.S. EPA, EPA/625/R-04/108, September 2004.
reuse
• Potable Water Reuse and Public Health Workshop, Centers for Disease Control, 2004.
• Water and Wastewater Industry Energy Efficiency: A Research Roadmap, AwwaRF and the California Energy Commission, 2004.
• Water Recycling 2030, California Department of Water Resources, 2003.
• Desalination and Water Purification Technology Roadmap: A Report of the Executive Committee, U.S. Bureau of Reclamation and Sandia
National Laboratories, 2003.
• Review of the Desalination and Water Purification Technology Roadmap, National Research Council of the National Academies, 2004.
• Water Desalination: Findings and Recommendations, California Department of Water Resources, October 2003.
WateReuse Foundation Reports addressing research needs:
Q6. Key factors of success
that would support the future
development of water reuse
Q7. Ongoing, planned, and
completed research projects
• Water Reuse Economic Framework Workshop Report (03-006-01)
• Water Reuse Research Needs Workshop – Summary Report (03-010-01)
• Research Needs Assessment Workshop: Human Reactions to Water Reuse (03-011-01)
A. A better understanding of the potential public health impacts of reclaimed water is needed to address public acceptance.
B. Addressing public perception and acceptance on the use of reclaimed water for both nonpotable and indirect potable reuse including
addressing psychological barriers such as breaking the source-quality connection.
C. Better marketing of reclaimed water including the development of a user-friendly list of water reuse definitions to replace the current
technical jargon (e.g., augmentation water versus indirect potable reuse).
D. Characterizing the full range of costs and benefits associated with water reuse projects would allow for more informed comparisons of
water reuse projects with alternative projects. Typically, benefits are underestimated for reclaimed water.
E. Addressing emerging contaminants of concern by advanced treatment technologies.
F. Lowering the energy requirements of advanced treatment technologies.
G. Addressing the significant issue of concentrate disposal especially for inland communities.
H. Streamlining institutional requirements such as permitting and regulatory issues surrounding water reuse projects.
I.
Including water reuse in local and regional planning processes including the use of Integrated Resources Planning.
J.
Environmental issues associated with siting or permitting a project.
WateReuse Foundation Completed Reports:
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Best Practices for Developing Indirect Potable Reuse Projects: Phase 1 Report (01-004-01)
Water Reuse Economic Framework Workshop Report (03-006-01)
Water Reuse Research Needs Workshop – Summary Report (03-010-01)
Research Needs Assessment Workshop: Human Reactions to Water Reuse (03-011-01)
Current WateReuse Foundation Projects:
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Develop Low Cost Analytical Method for Measuring NDMA – WRF-01-001
Removal and/or Destruction of NDMA in Wastewater Treatment Processes – WRF-01-002
Understanding Public Concerns of Indirect Potable Reuse Projects – WRF-01-004
Rejection of Wastewater-Derived Micropollutants in High-Pressure Membrane Applications Leading to Indirect Potable Reuse: Effects of
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Q8. Current research needs
A.
that are related to water reuse
and prioritize if possible
Membrane and Micropollutant Properties – WRF-02-001
Investigation of NDMA Fate and Transport – WRF-02-002
Filter Loading Evaluation for Water Reuse – WRF-02-003
National Database of Water Reuse Facilities – WRF-02-004
Develop a National Salinity Management Clearinghouse – WRF-02-005
Zero Liquid Discharge and Volume Minimization for Water Utility Applications – WRF-02-006a
Beneficial and Non-Traditional Uses of Concentrate – WRF-02-006b
Impacts of Membrane Process Residuals on Wastewater Treatment – WRF-02-006c
Regional Solutions for Disposing of Concentrate – WRF-02-006d
Comparative Study of Recycled Water Irrigation and Fairway Turf – WRF-02-007
Study of Reclaimed, Surface, and Ground Water Quality – WRF-02-008
Study of Innovative Treatment on Reclaimed Water – WRF-02-009
Pathogen Removal and Inactivation in Reclamation Plants - Study Design – WRF-03-001
Marketing Strategies for Non-Potable Recycled Water – WRF-03-005
Economic Analysis of Sustainable Water Use - Benefits and Cost – WRF-03-006
Reclaimed Water Aquifer Storage and Recovery: Potential Changes in Water Quality – WRF-03-009
Water Reuse Research Needs Workshop – WRF-03-010
Salt Management Guide – WRF-03-012
Development of Indicators and Surrogates for Chemical Contaminant Removal during Wastewater and Water Reuse Treatment (Co-funded
project with WERF) – WRF-03-014
Potential and Pitfalls for Sustainable Underground Storage of Recoverable Water (NRC Project) WRF-04-001
Water Conservation on Golf Course Fairways Using Recycled Water – WRF-04-002
Honolulu Membrane Bioreactor Pilot Study – WRF-04-004
Use of Recycled Water for Community Gardens – WRF-04-005
Water Reuse on School Yards and Parks – WRF-04-006
Understanding Mental Models of Water: Origins, Quality, Contamination, Naturalness, and Risk – Development and Testing of 3-5 Year
Research Plan – WRF-04-008
Reclaimed Water Inspection and Cross Connection Control Guidebook – WRF-04-009
Extend the Integrated Resources Planning (IRP) Process to Include Water Reuse and Other Non-Traditional Water Sources – WRF-04-010
Application of Microbial Risk Assessment Techniques to Estimate Risk Due to Exposure to Reclaimed Waters – Phase 1 – WRF-04-011
Development of a Guidance Document for Applying Sound Statistics for Exploring, Interpreting, and Presenting Microbial Data Associated with
Reclaimed Water Systems – WRF-04-012
Improved Sample Collection and Concentration Method for Multiple Pathogen Detection – WRF-04-013
Decision Support System for Selection of Satellite versus Regional Treatment for Reuse Systems – WRF-04-014
Joint Water Reuse & Desalination Task Force Desalination Workshops – WRF-04-015
Water reuse. The WateReuse Foundation held a Water Reuse Research Needs Workshop in February 2004. At this workshop, 96 high
priority research projects were identified. Foundation is using this list of priority projects to identify and fund projects under the Foundation’s
Solicited Research Program. The 96 projects are distributed under four topics areas: 1) Social and Policy Sciences; 2) Microbiology; 3)
Chemistry and Ground Water Recharge (including Aquifer Storage and Recovery); and 4) Treatment Technologies. Project descriptions for
the 96 projects are captured in the Foundation report titled “Water Reuse Research Needs Workshop – Summary Report” (03-010-01).
B.
Q9. Priority water reuse
research needs that can or
Desalination. The WateReuse Foundation is part of a project that is being initiated by the Joint Water Reuse & Desalination Task Force,
which also includes AwwaRF, U.S. Bureau of Reclamation, and Sandia National Laboratories. The purpose of the project is to identify
projects needed to implement the “Desalination Roadmap” developed jointly by USBR and Sandia by holding a series of workshops in 2005 of
stakeholders and interested parties.
Significant areas of interest and topics of concern in the U.S. include (in no particular order):
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should be addressed through
the GWRC or other international research effort
Q10. Potable reuse issues
A.
The increased use of “nontraditional” water sources including: treated municipal and industrial effluents; storm water; agricultural runoff;
brackish ground water and other impaired ground waters; and ocean water.
B. The use of aquifer storage and recovery (ASR) to store reclaimed water on a seasonal basis or for long-term storage for nonpotable
applications. In addition the use of aquifer, storage, transfer, and recovery (ASTR) in which separate recovery wells are used.
C. The use of groundwater recharge and surface water augmentation as indirect potable reuse.
D. Advances in technologies are needed to cost-effectively and reliably create new sources of water from “nontraditional” water supplies by
removing a wide range of contaminants than is possible with conventional water treatment processes. Possibilities include advances in
membrane technologies, advances in thermal techniques, and the development of alternative technologies.
E. Advances in managing the concentrate and residuals from membrane treatment including alternative disposal options, volume minimization
technologies, zero liquid discharge technologies, and beneficial uses of concentrate and separated salts.
F. Addressing “emerging pollutants of concern” or EPOCs including endocrine disrupting compounds, pharmaceuticals, household and
personal care products, and other substances that remain as trace micropollutants in treatment wastewater effluent. Topics include: public
health implications, removal by current treatment technologies, and the development of new generation technologies.
G. The fate and transport of chemicals and pathogens during irrigation with reclaimed water.
H. The use of satellite and decentralized treatment for water reuse applications.
I. Better understanding of the public’s perception and acceptance of water reuse (nonpotable and indirect potable reuse)
J. Better characterizing the economics (including benefits) of water reuse
K. Developing better marketing strategies for water and wastewater agencies.
Indirect potable reuse is practiced in the United States by several communities. These well-planned, well-engineered water supply projects
(e.g., Orange County’s Groundwater Replenishment System, Scottsdale’s Water Campus, and West Basin Municipal Water District’s Water
Recycling Facility) are considered to be very successful and are held up in their communities as significant achievements. In the past few years,
however, several proposed indirect potable reuse projects have stalled or have been canceled primarily due to public opposition. The
WateReuse Foundation is completing a current project titled “Understanding Public Perception of Indirect Potable Reuse Projects” (WRF-01004) that is looking at this issue by identifying best practices (see report titled “Best Practices for Developing Indirect Potable Reuse Projects:
Phase 1 Report”) and developing marketing tools for water agencies.
More communities in the U.S. are considering indirect potable reuse to meet increasing water supply demands. Currently, however, indirect
potable reuse can only be permitted in a handful of states. In addition, water agencies proposing indirect potable reuse projects are still
confronted with significant public opposition.
Q11. Other relevant information in the field of reuse
Q12. Desalination issues
and/or research needs
As a result, agencies considering indirect potable reuse must address the significant issue of public acceptance before a project will be approved
by decision makers (i.e., elected officials, senior water agency managers, etc.).
Emerging trends and potential barriers to water reuse:
A. The cost of energy is a significant driver for advanced technologies, including desalination. Research questions: 1) compare energy costs for
different water supply alternatives; and 2) develop treatment alternatives requiring lower energy requirements.
B. As other options become unavailable, more communities in the U.S. are considering indirect potable reuse to augment their potable water
supply. Research questions: 1) what are the most practical indirect potable reuse schemes – groundwater recharge, surface water or
reservoir augmentation – what are the pros and cons; and 2) develop proven methods to address public perception.
C. Storage during the wet season for use during the dry season or storage during times of normal precipitation for use during droughts is a
significant issue to expand the use of reclaimed water. Research questions: What are the limitations to ground water recharge and aquifer
storage and recovery and how can these limitations be overcome?
D. As communities move towards membrane treatments, the issue of concentrate disposal (management) can become the driving factor for the
success (or failure) of a project – especially for inland communities that do not have access to ocean disposal.
E. Holistic approach of integrating water reuse into water resource planning on a local and regional basis to overcome regulatory and institutional
barriers. Research questions: How can water reuse be incorporated into approaches such as Integrated Resources Planning?
According to the California Desalination Task Force Report (Water Desalination: Findings and Recommendations, California Department of
Water Resources, October 2003), the following are key issues:
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Permitting and Regulatory Issues
i. Information needed
ii. Water rights
iii. Bay and ocean designated as a drinking water supply
iv. International trade issues
v. Science-based approaches
Energy Issues
i. Factors contributing to energy costs
ii. Energy use comparisons between desalination and alternatives
iii. Issues with co-location with energy and other facilities
iv. Methods to reduce costs
v. Green energy markets
Economic Issues
i. Realistic assessment of economic costs
ii. Direct and indirect costs of desalination version alternatives
iii. Framework for benefit/cost analysis
iv. Holistic approach to analysis of water supplies (including water reuse and conservation)
Planning Issues
i. Growth inducement
ii. Links between planning and water supply demand
iii. Environmental and water quality benefits from brackish water treatment
iv. Regional water projections/plans
v. Water supply diversification
vi. Small versus large scale approach
vii. Multi-jurisdictional cooperation
Siting Issues
i. Land use and infrastructure compatibility
ii. Public access
iii. Guidelines and criteria
iv. Impacts on wetlands and terrestrial habitats
v. Impacts of intake and discharge locations
Feedwater intake
i. Options for feedwater
ii. Source water quality, pretreatment and their impacts
iii. Entrainment and impingement impacts
iv. Affected organisms and how they are affected
v. Ecological impacts
vi. Existing and needed mitigation measures
Distribution and Outfall Issues
i. Stability and impact on distribution systems
ii. Disposal of residual materials from desalination processes
iii. Optimal marine/estuarine substrates for outfall locations
iv. Approach to managing concentrate, addressing dispersion.
v. Waste stream characterization
vi. Water quality, including impacts of blending with powerplant, wastewater, or other discharges
vii. Ecological impacts of concentrate disposal
Public Health
i. Consumption of product water
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