WASTEWATER TREATMENT SYSTEMS
BY: AHMED ALHAMADAT
Contaminants of Concern:
 Pathogens
– Bacteria, viruses, protozoa
Coliform count is usually 105 – 106 /mL
in raw sewage
 Inorganic chemicals
– Total dissolved solids
 Unregulated and unidentified
trace organic chemicals
– Pharmaceuticals
– Personal care products and
household chemicals
– Endocrine disrupting chemicals
– Emerging disinfection by-products
Pharmaceutically active
compounds (PhACs)
Wastewater Characteristics
 Wastewater refers to liquid discharged from residential,
business buildings and institutions.
 Industrial wastewater is discharged from manufacturing
plants.
 Municipal wastewater is the general term applied to the
liquid collected in sanitary sewers and treated in municipal
plants
 Domestic sewage is composed of human body waste and
sludge which is the wastewater resulting from personal
washing, laundry, and cleaning of kitchen utensils
• Raw wastewater chemical constitutes (mg/l):
BOD
COD
TSS
metals
TN
100-500 300-800
100-350
<1
20-85
TP
4-15
Water recycling is reusing treated wastewater for beneficial purposes such as
agricultural and landscape irrigation, industrial processes, toilet flushing, and
ground water recharge – USEPA Region 9 Water Program
Recycled or reclaimed water is water that is used more than one time before
it passes back into the natural water cycle.
– Water Reuse Association
• Wastewater
New
Water Resource
“ Reuse”
Treatment Technologies
Water
with
High
Quality
Objectives of WWT
n
Reduce organic content (BOD & COD) and TSS
n
Removal/reduction of nutrients i.e., N,P
n
Removal/inactivation of pathogenic microbes
Typical Stages in a Conventional Wastewater Treatment Operation
Wastewater production, treatment and reuse in Saudi Arabia, 2009
14% reused only
26% collected
80% treated
(Arani Kajenthira et al, 2012)
Potential energy savings from increasing the use of treated
wastewater rather than desalination in the municipal sector
How do we clean our wastewater?
Trace
chemicals,
Energy:
CO2
VOCs
H2 S
CH4
Pumping
Mixing
Aeration
Disinfection
Heat for digester
Chem transportation
Clean water
Chemicals:
Bioproducts
Flocculation
Precipitation
Disinfection
Labor:
O&M
Biosolids, Nutrients,
biopolymers
Unrecoverable
waste residuals
A more sustainable approach
Problems associated with WW reuse
 The real cost of the projects are usually considerably
higher than that estimated previously. This is in large
part a result of insufficient planning before design
and construction of water reclamation projects
 Presence of pathogens in water, chemical contaminants
or heavy metals because of insufficient treatment
The positive effects of using wastewater irrigation
Economic feasible water resource
It conserves potable water
It reduces pollution of receiving water bodies e.g. rivers,
canals and other surface water resources
It decreases the needs for chemical fertilizers
It increases crop yields
It provides a reliable water supply to farmers
The potential negative effects of wastewater irrigation
Health risks for irrigators and communities with prolonged
contact with untreated wastewater and consumers of
vegetables irrigated with wastewater
Contamination of groundwater (nitrates)
Build-up of chemical pollutants in the soil (heavy metals)
Creation of habitats for disease vectors
Excessive growth of algae and vegetation in canals
carrying wastewater (eutrophication)
Challenges associated with WW reuse
1. Social acceptance (farmers, retailers and consumers):
This is the most sensitive area of this topic. Farmers are not going
to reuse water, if their product cannot be sold. Consumers will not
buy products where reuse water was used unless it is proven to
be safe
2. Social issues: play a significant role in
water reuse initiatives and should be
adequately addressed. With adequate
political will accompanied by awareness
programmes these cultural, religious and
social objections can be overcome.
3. Water quality monitoring: TE should
be tested on regular basis to guarantee
the matching with standards

The non-regulated use of treated water in agriculture

The non-existing reuse criteria related to hygiene, public
health and quality control

The non-existing reuse criteria related to irrigation
techniques, degree of wastewater treatment, and choice
of areas and types of crops to be irrigated

The lack of efficient control and monitoring of urban
wastewater treatment plants

The lack of trained personnel both in the competent
authorities and the treatment plants

The low level of awareness of the farmers and the public
at large
Wastewater as a renewable
resource
A paradigm shift is underway!
Graphics: Jeremy Guest
http://www.sustainlane.com/reviews/getting-the-most-from-humanwaste/ICF8A2T14UAQ9HTV27Q8VLQXRTOI
http://www.myfoxtampabay.com/story/18612
577/could-a-new-energy-source-start-righthere
Thank You
and
Any
Question?
Costs
 Wastewater reclamation system costs are a function of facility
capacity, end-use option and treatment process configuration
 Costs can be identified estimating:
- facility construction costs
- equipment purchases and
- operation and maintenance fees
 Site development and electrical cost are assumed as 10 and 15
percent of the total facility costs respectively
Costs
 Reclamation system’s annual cost is comprised of treatment and
distribution facility personnel salaries, operating fees (recurring
power and chemical cost) and maintenance cost (equipment repairs
and replacements)
 Personnel requirements are a function of facility size and
complexity
 Maintenance cost (spare parts, replacements) are estimated
generally as a percentage of equipment first cost (e.g. 5 %)
 For pipelines and storage tanks, maintenance costs are projected as
two percent of capital costs