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Making use of the energy we’re flushing away
Nick Meeten
Senior Engineer, Smart Alliances – New Zealand [email protected]
Wednesday 15th April – 1.30-3.15pm
Keywords: Energy, Sustainability, Wastewater
Abstract
To become sustainable, cities need to make use of every possibility to become more efficient.
Within city centres many commercial buildings typically have excess heat energy, most of if not
all of the year round. This excess heat is rejected to atmosphere as ‘waste heat’ from air
conditioning systems, which then contributes to the ‘Urban Heat Island’ affecting many cities.
Rejecting this heat requires significant energy, and once the heat energy is discharged to
atmosphere it is lost. Yet there are other potential users of this low grade heat, including
wastewater treatment plants. Water is an excellent conductor of heat, and wastewater flows
through cities at stable and neutral temperatures. Using the network of wastewater
infrastructure systems and the thermal energy capacity of the wastewater flowing therein is a
possibility which is currently almost entirely ignored. Yet within cities in temperate climate
zones, wastewater could absorb in the order of 30% - 40% of the excess heat from commercial
buildings and offer multiple benefits including; reduced energy consumption and costs for the
respective building customers, reduced Urban Heat Island effect, reductions in peak demand for
electricity supply infrastructure, improved wastewater treatment processes (resulting in lower
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environmental pollution) and increased wastewater treatment plant capacity with associated
reduced operating costs for wastewater utilities and possibly a new revenue stream.
Introduction
Note 1: This paper crosses multiple sectors, and is aimed at an audience of professionals from
the Urban Built environment (e.g. urban planners, architects, engineers etc.), Utility providers
(energy and wastewater supplies) and City officials. It is assumed that any individual reader is
unlikely to be familiar with every subject area. So the paper deliberately tries to avoid technical
jargon and delving deeply into technical detail, in the hope that the wide ranging topics can be
grasped by all. The paper is split into two main topic areas; Part 1 considers the built
environment of cities and energy usage in commercial buildings. Part 2 considers wastewater as
an energy source, looking at flows, infrastructure and treatment.
Note 2: In this paper we refer only to ‘heat pumps’. However where cooling systems are being
discussed, ‘heat pump’ can also be considered the same as ‘chiller’.
As the world tackles well documented trends of population growth, urbanization, middle class
growth in developing countries (in particular India and China), climate change and rising energy
demands, cities need to use every possible opportunity to improve their resource and energy
efficiency to become sustainable.
Any city contains a wide variety of buildings. These buildings vary in age, construction,
proportions and function. Accordingly they also vary in how and when they require energy for
the Heating, Ventilation and Air Conditioning (HVAC) systems to maintain a comfortable internal
environment. Within developed countries, the majority of buildings which will be required in
the year 2050 are already built (UNEP), and improving the efficiency of this existing building
stock is a massive challenge globally.
In addition, many cities are facing large capital investment programmes to either replace aging
wastewater infrastructure, or install new wastewater infrastructure to cope with growth. If this
network of below ground pipes can be utilised for more than just moving wastewater, by also
helping improve the energy efficiency of the city, the investment case should be improved
significantly.
Typical municipal wastewater is approximately 99.9% water and 0.1% pollutants (UN FAO). Yet
flowing through city sewers, this water is a hidden and almost entirely ignored source of energy.
It is reliable, since its availability and capacity is relatively constant, irrespective of the seasons,
and independent of wind or sun. It is widely available, since wastewater infrastructure typically
covers the entire built area of cities. With a stable and neutral temperature range, within
temperate climate zones wastewater is often warmer than ambient in the winter and cooler
than ambient in the summer. Water is also an excellent conductor of energy. With a specific
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heat capacity four times greater than air, water can therefore move around four times as much
energy as air. This combination of factors makes wastewater an excellent source for the low
grade heating or cooling energy needed by HVAC systems of commercial building, either for
direct passive cooling or for higher grade heating and/or cooling when used in conjunction with
heat pumps.
It is estimated that there are more than 500 wastewater energy recovery systems installed
globally, with the first installations made over 25 years ago (Schmidt 2008). The technology for
utilizing this energy source is available and proven in operation, but adoption of the concept has
not yet achieved scale and so the potential capacity available is not utilized.
PART 1: ENERGY USAGE IN COMMERCIAL BUILDINGS AND CITIES WITHIN TEMPERATE
CLIMATES
1.1 General
Within commercial buildings such as offices, educational facilities or retail malls, to satisfy the
majority of occupants target internal temperatures are typically in the range 19 oC – 24oC (dry
bulb).
1800
There are some types of buildings which require heating energy all year around (even in
summer).
1600 Examples of these include indoor swimming pool complexes and hospitals.
Sys load (kW)
There1400
are however significantly more buildings that require cooling most of, if not all year
around (even in winter). These typically include; Office buildings (figures 1 and 2),
entertainment
venues, data centres, educational facilities, airport terminals and retail malls.
1200
Even in Mid-Winter
cooling is dominant
load from mid-morning
1000
800
600
400
200
0
00:00
06:00
12:00
18:00
00:00
Date: Wed 17/Jan
Room cooling plant sens. load: (space heating and cooling profiles.aps)
Room heating plant sens. load: (space heating and cooling profiles.aps)
Figure 1: Mid-Winter Daily Heating and Cooling Demand for an 11 story office building in
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London, UK
(supplied by Atelier Ten)
1800
1600
1400
Sys load (kW)
1200
1000
800
600
400
200
0
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
Date: Mon 01/Jan to Mon 31/Dec
Room cooling plant sens. load: (space heating and cooling profiles.aps)
Room heating plant sens. load: (space heating and cooling profiles.aps)
Figure 2: Annual Heating and Cooling Demand for an 11 story office building in London, UK
(supplied by Atelier Ten)
The HVAC systems for commercial buildings typically consume 25%-45% of the total energy
used by the building. Current conventional HVAC systems satisfy building heating/cooling
demands via either (a) burning of fossil fuels (e.g. gas, oil) or (b) electrically driven refrigeration
systems such as chillers or reverse cycle heat pumps. In the latter case, atmosphere is the
predominant prime energy source accessed through air based heat exchangers located outside
the building (so called ‘Air Source’ heat pumps).
New buildings or buildings undergoing major refurbishment are increasingly using technologies
such as recuperators and thermal wheels to improve their energy efficiency, and the efficiency
of these technologies lies in the range of 45% - 75% (The CarbonTrust). However retrofitting
these technologies into existing building systems is often impractical.
Ultimately both the energy used within the building (HVAC energy and electrical energy for
lighting and small power) and the solar energy received by the building, is almost entirely
converted to heat and some of this must be discharged as excess heat. Currently this is mostly
discharged into the atmosphere where it is then lost.
Jan
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There is growing use of heat pumps using alternative prime energy sources such as ‘Ground
Source’ heat pumps (utilising a heat exchanger buried in the ground) and ‘Water Source’ heat
pumps (utilising water sources such as ground water, rivers, lakes or sea). Whilst these ground
source and water source systems are unquestionably efficient, within cities there are practical
considerations which limit their implementation such as:



Availability of space for Ground Source – for central city commercial sites, there is rarely
free land area available for the installation of ground source heat exchanger pipework.
Access to Water Sources – It is rare for cities to have widely distributed networks of
natural water sources running through them. If there are flowing water bodies (e.g.
rivers or streams) they are typically low in number. If the city is abutting a larger water
body (e.g. lake or ocean) then typically only one side of the city can access this water.
Environmental issues for Water Source - with water source systems using river/lake
water, there are often concerns for the natural ecosystems with respect to withdrawing
water (destruction of insects, fish eggs etc.) and with changing the temperature of the
water.
With both ground source and water source systems, the energy released by the buildings
(whether that be heating or cooling) is lost into the receiving environment, and thus cannot be
recovered and reutilised by others.
1.2 Heat Pump System Efficiencies
The operating efficiency of a heat pump is referred to as the Coefficient of Performance (COP).
This is the ratio of heating or cooling energy provided, to the electrical energy consumed. Higher
COP’s equate to lower operating costs.
For conventional building cooling systems using air source heat pumps, the efficiency of the
system in cooling mode decreases as the ambient temperature increases (Table 1). This is due to
reducing heat pump COP as the ambient temperature gets closer to the heat pump condenser
temperatures and the heat transfer capability is reduced. Hence on hot days as the need for
cooling increases, the efficiency of conventional air source cooling system decreases as its ability
to reject the waste heat decreases.
Table 1
Condensor Leaving Temp (oC)
10
15
20
25
30
35
40
Typical COP
6.0
5.2
4.7
3.9
3.4
3.1
2.8
Source: Chen et al (2011) and aggregated data from various heat pump manufacturers
The same is also true in the reverse situation when heating is required. On cold days, as the
ambient temperatures drop (and hence the need for heating increases) the COP’s of heat
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pumps also drops as evaporator temperatures are forced lower to stay below ambient and
allow heat transfer to take place.
From the data in Table 1, it can be seen that when a heat pump in cooling operation can reject
heat into a fluid which is 10oC cooler, the heat pump will operate approximately 30% more
efficiently (and so require approximately 30% less electricity).
1.3 Electricity Demand and Price Profiles
Peak demands on the electrical supply networks for cities are typically experienced on summer
afternoons and these demand peaks are heavily influenced by the HVAC cooling loads from
commercial buildings (Figure 3). Since the capacity of all components of a city’s electrical supply
infrastructure is driven by the maximum demand placed upon the network, electrical supply
authorities typically make every attempt to reduce the extent of these peak loads.
Figure 3: Typical Commercial Building Energy Consumption by End Use
http://www.businessspectator.com.au
It is therefore typical for electricity retailers to have different pricing structures for energy used,
depending upon the time of day and time of year. Electricity charges are typically made up of
different components, the two dominant ones being charges for network capacity (i.e. having
capacity made available to the site) and for energy actually consumed. Typically the electricity
consumed has at least two price categories (normally termed ‘Peak’ and ‘Off Peak’) although
sometimes there may be more than two price categories (as in the example provided here in
Figure 4).
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Figure 4: Example of Electricity Price Categories
As can be expected, ‘peak rate’ electricity is the most expensive, and the costs associated with
having every kilowatt of ‘network capacity’ provided to the site (even though this capacity may
only be fully utilised a few minutes every month) are also often significant.
It is not considered necessary in this paper to go into more detail regarding the pricing of
electricity, since these characteristics are widely established and generally well known. The
intention here is to illustrate that electricity consumed in the process of cooling commercial
buildings tends to be expensive, because it is mostly required at peak daily demand times,
during peak season. Any savings in electricity (both in maximum demand and energy consumed)
achieved through improving the efficiency of a buildings cooling system, should result in high
financial savings in electricity charges.
1.4 Urban Heat Island Effect
Many medium to large cities suffer (to varying degrees) from ‘Urban Heat Island’ effect. In cities
subject to the Urban Heat Island effect, temperatures inside the city are typically 2 oC – 5oC
higher than in the rural areas immediately outside the city, and in extreme cases this difference
can be up to 12oC (US EPA).
This is due to the combined effects of large scale use of sealed surfaces such as concrete, glass
and asphalt, and the rejection of waste heat from buildings into the atmosphere. Research in
Japan and France indicates that within the cities analysed waste heat being rejected from air
conditioning systems raises the temperatures by 1oC-2oC (Ohashi et al; de Munck et al; Figure
5). Also with global temperatures predicted to rise due to climate change, this situation will
worsen as more buildings adopt air conditioning.
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With higher temperatures within cities, in summer the efficiency of conventional air source
building cooling systems is correspondingly decreased and electricity demand is increased.
Akbari et al. estimate that the heat island effect is responsible for 5–10% of peak electricity
demand for cooling buildings in cities.
Figure 5: Elevated Paris CBD temperatures due to Air Conditioning waste heat
(de Munck et al)
Summary Part 1
Many commercial office buildings in temperate climate cities have an excess of heat throughout
most of, if not the entire year (including winter). Removing this excess heat energy to maintain
confortable conditions within the buildings typically requires the use of expensive peak rate
electricity, the demand for which peaks on summer days. This is also when conventional air
source HVAC cooling systems operate least efficiently.
This excess heat is currently mostly discharged into the atmosphere, where it is lost. Waste heat
from air conditioning systems has been shown to add 1oC – 2oC to Urban Heat Island effects in
some cities, and as temperatures increase due to climate change, this situation will only worsen.
PART 2: WASTEWATER AS AN ENERGY SOURCE
2.1 Daily Flow Profiles
The daily flow profiles at any point in a wastewater network are determined by what is
occurring upstream of that point. Whilst residential zones within a city typically have a slightly
different usage pattern to commercial and industrial zones, the wastewater flows in any
network are heavily linked to the times of day when people are active. This profile also matches
with the times of day when commercial buildings are occupied and hence the times of day when
building HVAC systems need energy (Figure 6).
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Figure 6: Typical Wastewater Daily Flow Profiles
2.2 Temperatures
In temperate climate zones, wastewater temperatures are generally relatively stable
throughout the year, and typically within the range 10 oC – 20oC (Figure 7). It should be noted
however that in colder regions subject to snow, where a combined storm water and wastewater
system is used, during periods of snow melt the temperatures of wastewater can fall into the
range 3oC – 5oC due to infiltration.
It can also be seen that in many locations, for large periods of the year, wastewater
temperatures are under the 19oC – 24oC target internal temperatures of many commercial
buildings. In these situations wastewater has capacity to directly provide passive cooling for
buildings. If passive cooling is sufficient it could allow the heat pump to be bypassed and
switched OFF leading to higher electricity savings during these periods.
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Figure 7: Wastewater temperatures from various temperate region cities.
When assessing the capacity of a city’s wastewater system to absorb heat, the limit will be
determined by the maximum acceptable temperature during the summer season. We have
assumed that an increase in temperature of 5oC should be acceptable in most temperate
climate zones, as this would mean on average an increase in peak summer wastewater
temperatures from 20oC to 25oC.
2.3 Accessibility
To ensure public health security, cities strive to collect 100% of wastewater. There are
significant variations in the provision of ‘Piped On Premises’ Sanitation in Urban populations
globally (Table 2). The scope of this paper is limited to temperate climate zones, and within
these climate zones the vast majority of countries fall into either ‘developing’ or ‘developed’
classifications. From this and the data in Table 2, we can therefore assume that most cities
within temperate climate zones will have wastewater infrastructure coverage to the majority of
the built area and the buildings therein. Hence the vast majority of commercial buildings
covered by the scope of this paper should have access to wastewater infrastructure and
wastewater flows.
Table 2
Least Developed
Developing
Countries
Countries
% Urban – Piped On Premises
33%
74%
Source: WHO Unicef Sanitation and Drinking Water JMP 2013 Update
2.4 Effects of Warmer Wastewater on Below Ground Infrastructure
Developed
Countries
97%
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The problems of Microbial Induced Corrosion (MIC) of concrete sewer pipes are reasonably well
understood, however the processes involved are complex. There are multiple factors involved
such as: age of the infrastructure, Hydrogen Sulphide (H2S) production, pH levels, wastewater
characteristics, biofilm formations, flow velocities. Temperature is also a factor in the process
(Neetling Mah et al; Wells Melchers et al; Biggs et al). Baumgartner (1934) found that H2S
virtually ceased at 7oC. At warmer temperatures though there was little difference in H 2S
production patterns for samples kept at 30oC and 37.5oC (Neetling Mah et al 1989).
At the moderate wastewater temperatures concerned with this paper (i.e. within the range
15oC – 25oC) the impact on Microbial Induced Corrosion by raising the temperature of
wastewater in the order of 5oC appears to be relatively small.
2.5 Wastewater Treatment Efficiency
In cities using secondary wastewater treatment processes, the treatment process typically
utilises a biological treatment step. There are a variety of technologies available to achieve this,
and common examples of these include; activated sludge, sequencing batch reactors, trickling
filters, rotating biological contactors and moving bed biological reactors.
What these processes all have in common is that they rely on naturally occurring
microorganisms to perform part of the treatment process by consuming organic compounds,
converting nutrients into different forms and binding together less soluble compounds to allow
easier removal.
The effectiveness of these organisms (and hence the treatment process) is highly influenced by
the temperature of the environment in which they live (i.e. the wastewater). As wastewater
temperatures drop below approximately 20oC, the efficiency of the biological process also
decreases significantly (Collins, Grady et al) resulting in wastewater which is less well treated
being discharged into the environment.
The amount of excess sludge produced by the biological process is also influenced by the
temperature of the wastewater, as well as other factors such as sludge age. Treating excess
sludge is one of the major operating costs for a wastewater treatment plant, and any way to
reduce sludge volumes results in significant savings for wastewater utilities. Warmer
wastewater temperatures combined with shorter sludge ages can result in lower excess sludge
volumes (Collins, Grady et al).
Since the design of wastewater treatment plants must consider the worst case, when
considering temperatures, the process is normally designed for the conditions encountered
during winter (i.e. cold wastewater temperatures). This then determines the required sizes of
the various tanks and associated equipment required for the process. Raising the temperature
of the wastewater (as happens naturally during the summer months) increases the efficiency of
the biological process and means the tanks etc. are larger than required in these warmer
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conditions. Another way of looking at this is that for existing wastewater treatment plants,
designed for winter temperatures, raising the temperature of the wastewater during winter will
increase the capacity of the existing plant without requiring expensive civil works to increase
the size of tanks etc.
Summary Part 2
City wastewater systems carry reliable flows of neutral temperature water all year around and
the patterns of flow match very well with the patterns of when buildings are used.
A modest increase in temperature should not have a major effect on below ground
infrastructure, and could offer benefits to the wastewater treatment plant in winter.
Potential opportunities
Available Thermal Capacity within Wastewater Networks
Studies made in Switzerland and Germany indicate that ~3% of all buildings could be supplied
with heat (or cooling) on the basis of wastewater (Schmidt 2008).
However in this paper we have excluded residential buildings and focused on commercial
buildings for the following reasons:



The dominant HVAC energy demand of many commercial buildings is cooling, and there
is less likelihood of encountering a hard capacity limit when rejecting heat into
wastewater during summer, than when taking heat out of wastewater during winter (in
colder regions there is a very real possibility of reaching freezing point when extracting
heat from wastewater during periods of snow melt).
There are likely to be greater commercial benefits of improving HVAC system efficiencies
in cooling mode via utilisation of the passive cooling capacity of wastewater, and by
reducing the building maximum demand on summer afternoons (when electrical
demand charges typically peak).
Reducing the amount of heat rejected to atmosphere has additional benefits by also
helping to reduce the Urban Heat Island effect within cities.
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Figure 8:Illustrations showing Summer and Possible Passive Cooling in Spring/Autumn Seasons
As described in section 2.3 when assessing the potential capacity of wastewater systems within
cities, we have assumed that an increase in temperature of 5 oC should be acceptable in most
temperate climate zones.
Using these criteria, the potential opportunity offered by wastewater increases significantly
over figures previously reported. Table 3 shows high level breakdowns from a selection of cities
assuming a 5oC rise in wastewater temperature.
Table 3
New York
Los Angeles
Philadelphia
Population
(Millions)
19.5
3.8
1.5
Commercial
Building
Energy
Consumption
(GWh/year)
69,353
13,345
11,429
Daily
Wastewater
Volumes
(m3)
4,900,000
2,100,000
1,800,000
Thermal Energy
Capacity of
Wastewater
@5oC Δt
(GWh/year)
10,475
4,431
3,832
Commercial
Building
Energy
Capacity
from
Wastewater
~15%
~33%
~33%
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Melbourne
Munich
4.0
1.4
4,965
~6,000
877,000
1,800,000
1,752
3,832
~35%
~64%
The data used above has been sourced from websites for city governments and wastewater and
energy utilities except the following:


New York – Energy data sourced from NYC Inventory of Green House Gas emissions 2013
Melbourne – Energy data provided by City of Melbourne via personal communications
From the analysis above, the capacity for Munich appear to be unrealistically high, and further
investigation would be required to provide more certainty on this.
In the other cities considered, with a modest limit of 5oC rise in temperature, wastewater could
absorb 15% - 30% of the total heat energy consumed by commercial buildings in a city, with
many of them falling into the range 30% - 35%.
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Harvesting of Excess Heat Energy in City CBD’s For Reuse Downstream
If there exist opportunities downstream (in relation to wastewater flow direction) of a city’s
CBD’s to utilise low grade heat all year around, the potential opportunity to use wastewater
systems for removing excess heat from city CBD buildings could be increased further.
Industries which have all year around demands for low grade heat include: pulp and paper,
gypsum, food and drink and some chemical producers. These industries also tend to be located
on city fringes due to lower cost of land, ease of logistics etc.
Wastewater Treatment Plant
Industries with
demand for heat
energy
CBD with excess
heat energy
F
igure 9: Urban Transect Showing Harvesting of Heat for Reuse Downstream
(Image supplied by DPZ)
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Conclusions
The results indicate that for many commercial office buildings in temperate climate cities,
cooling is required throughout most of, if not the entire year (including winter). In summer
removing this excess heat energy to maintain confortable conditions within the buildings
requires the use of expensive peak rate electricity, and often contributes significantly to the
peak demands faced by the electrical supply infrastructure to the city. These summer conditions
are also when conventional air source HVAC cooling systems operate least efficiently.
Wastewater is an appropriate alternative source of cooling energy to remove this excess heat.
The infrastructure is widely accessible throughout temperate climate cities. Wastewater has
reliable flows, stable temperatures and the flow profiles match well to the occupancy profiles of
commercial buildings. The capacity of wastewater systems to absorb this excess heat energy
appears to be significantly larger than previously reported, falling into the range of 15% - 30% of
commercial buildings energy consumption for the cities considered.
There are multiple benefits available to different sectors,
In summer:



Building owners can benefit since typical temperatures of wastewater can offer
efficiency gains over cooling systems rejecting heat to atmosphere and hence reduce the
energy demand by up to 30%.
Electrical Utilities can benefit through reduced maximum demand loads on their
infrastructure, possibly allowing avoidance of capital investment to increase capacity.
The city environment can benefit through reduced Urban Heat Island effect.
In winter, with warmer wastewater:




The wastewater utility can benefit through improved biological treatment processes.
The wastewater utility can benefit through reduced sludge production volumes.
The wastewater utility can benefit through increased treatment plant capacity with little
or no capital expenditure or needing additional land area.
The receiving environment for the treated wastewater can benefit through better
biological treatment processes.
Harvesting excess heat energy from commercial buildings in a city CBD can also open the
possibility of allowing recycling of energy by making this energy available to suitable industries
located along the sewer route between CBD and the wastewater treatment plant.
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These multiple benefits can only be realised however, if a collaborative ‘partnering’ relationship
is adopted between the city built environment and the wastewater utilities.
References
1. Akbari, H. (2005). Energy Saving Potentials and Air Quality Benefits of Urban Heat Island
Mitigation
2. Biggs, Catherine A., Olaleye, Omolara I., Jeanmeure, Laurent F. C., Deines, Peter, Jensen,
Henriette S., Tait, Simon J. and Wright, Phillip C.(2011) 'Effect of temperature on the
substrate utilization profiles of microbial communities in different sewer sediments',
Environmental Technology, 32: 2, 133 — 144
3. CarbonTrust (2012) ‘Heat recovery, A guide to key systems and applications’
4. Chen J.S. , Boufadel M. , Haider E. , Wang J. , Wang A. (2011) Wastewater Heat Extraction
for Commercial HVAC Applications: A U.S. Pilot Project
5. Collins C.E., Grady C.P.L., Incropera F.P. (1978) The Effects Of Temperature Control On
Biological Wastewater Treatment Processes
6. de Munck, C., Pigeon, G., Masson, V., Meunier, F., Bousquet, P., Tréméac, B., Merchat,
M., Poeuf, P. and Marchadier, C. (2013), How much can air conditioning increase air
temperatures for a city like Paris, France?. Int. J. Climatol., 33: 210–227. doi:
10.1002/joc.3415
7. Neethling J.B., Mah R.A., Stenstrom M.K., (1989) Causes and Control of Concrete Pipe
Corrosion
8. Ohashi Y., Genchi Y., Kondo H., Kikegawa Y., Yoshikado H., Hirano Y. (2007) Influence of
Air-Conditioning Waste Heat on Air Temperature in Tokyo during Summer: Numerical
Experiments Using an Urban Canopy Model Coupled with a Building Energy Model
9. Schmidt (2008) Sewage Water: Interesting Heat Source
10. UN FAO: http://www.fao.org/docrep/t0551e/t0551e03.htm (accessed 12.03.2014)
11. UNEP: http://www.unep.org/sbci/pdfs/sbci-bccsummary.pdf (accessed 19.03.2014)
12. US EPA: http://www.epa.gov/heatisland/ (accessed 12.03.2014)
13. Wells P.A., Melchers R.E., Bond P., (2009) Factors Involved in the Long Term Corrosion of
Concrete Sewers.
Bio
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Nick Meeten is a senior engineer at Smart Alliances engineering consultants. He returned to
NZ in 2014, after living in Germany and working internationally as Green Buildings Team
Leader for water technology suppler HUBER, He is a professional member of the Institute of
Professional Engineers of New Zealand. Nick has more than 25 years experience in: design
of commercial building systems and urban infrastructure, project management of land
development and commercial building projects and design and implementation of water
recycling and energy recovery solutions.