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Prepared b the Cascadia Green Building Council
March 2011
TOWARD NET ZERO WATER:
BEST MANAGEMENT PRACTICES FOR
DECENTRALIZED SOURCING AND TREATMENT
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Toward Net Zero WaterPage 2
Acknowledgements
SPONSORED By
Compton Foundation
PRIMARy AUTHORS
Joel Sisolak, Advocac and Outreach Director, Cascadia Green Building Council
Kate Spataro, Research Director, Cascadia Green Building Council
CONTRIBUTORS
Jason F. McLennan, CEO, Cascadia Green Building Council
Marin Bjork, Research Manager, Cascadia Green Building Council
Leslie Gia Clark, Cascadia Corps Volunteer
Gia Mugford, Cascadia Corps Volunteer
Samantha Rusek, Cascadia Corps Volunteer
PEER REVIEW
Morgan Brown, President, Whole Water Sstems, LLC
Mark Buehrer, P.E., 2020 ENGINEERING
Scott Wolf, AIA, Partner, The Miller/Hull Partnership, LLP
Pete Muoz, P.E., Natural Sstems International
COPyRIGHT INFORMATION
This report is the copyrighted property of the Cascadia Green Building Council, all rights reserved 2011.
This report may be printed, distributed, and posted on websites in its entirety in PDF format only and for
the purposes of education. This report my not be altered or modied without permission.
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Toward Net Zero Water Page 3
tAble of contents
ExECUTIVE SUMMARy . . . . . . . . . . . . . . . . . . 1
INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . 2
CONTExT AND BACKGROUND . . . . . . . . . . . . . . 8
Histor Of Centralized Water Sstems
Current Conditions: Environmental, Social &
Economic Risks Moving Forward: A Vision for Net Zero Water
Current Barriers to Net Zero Water
BEST MANAGEMENT PRACTICES . . . . . . . . . . . .30
Integrated water management
Fitandefciency
Communit Involvement
Risk Management
Beaut and Inspiration
RAINWATER HARVESTING . . . . . . . . . . . . . . . .44
Denition Sstem Components
Technolog
Fit
Efciency
Additional Design Considerations
Additional Resources
GREyWATER RECLAMATION & REUSE . . . . . . . . .62
Denition
Sstem Components
Technolog Fit
Efciency
Additional Design Considerations
Additional Resources
WASTEWATER TREATMENT & REUSE. . . . . . . . . .78
Introduction
Composting Toilets. . . . . . . . . . . . . . . . . 80
Sstem Components
Technolog
Fit
Efciency
Additional Design Considerations
Constructed Wetlands . . . . . . . . . . . . . . . 90
Sstem Components
Technolog
Fit
Efciency
Additional Design Considerations
RecirculatingBiolters . . . . . . . . . . . . . . 100
Sstem Components
Technolog
Fit
Efciency
Additional Design Considerations Membrane Bioreactors . . . . . . . . . . . . . . 106
Sstem Components
Technolog
Fit
Efciency
Additional Design Considerations
Additional Resources . . . . . . . . . . . . . . . 114
FUTURE RESEARCH . . . . . . . . . . . . . . . . . . . 115
GLOSSARy . . . . . . . . . . . . . . . . . . . . . . . . 119
BIBLIOGRAPHy. . . . . . . . . . . . . . . . . . . . . . 122
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Toward Net Zero Water Page 1
executive summAryToward Net Zero Water is a best management practices manual on decentralized strategies for water
suppl, on-site treatment and reuse. It was conceived through an etensive literature review on the topicsof site and district-scale water sstems with a focus on best-in-class eamples from around the globe.
This manual is intended to assist developers and regulators of water sstems to better understand these
strategies and how the might be applied in American cities.
NorthAmericancommunitiesfacesignicantwater-relatedchallenges.Growingurbanpopulations
demand epanded water and wastewater services, while aging water suppl and wastewater treatment
infrastructure, most of which was designed and built in the late 19th and earl 20th centuries, approaches
end-of-life or is in need of major overhaul. This growing crisis is further eacerbated b unsustainable
water use patterns. Ever da, we use potable water within our buildings for non-potable functions such
aswashingclothesorushingtoilets,allwithlittleornoattemptatreuse.Further,alterationsinlocaland
global climate patterns pose additional risks to the health and resilience of our water sstems.
In recent ears, the green building movement has made strides to change the wa people view water
resources, raising awareness and increasing implementation of water conservation techniques. Despite
this progress, green buildings have not come far enough, fast enough to address the challenges that face
our cities water infrastructure. A widespread adoption of more integrated sstems that include suppl,
treatment and reuse of water at the building and neighborhood scale is an important strateg for increasing
the resilienc of our water sstems.
The incorporation of decentralized strategies for water suppl, on-site treatment and reuse requires a
major shift in the mindset of how buildings are conceived, designed, regulated, built and operated. Insight
into the current conditions of our water sstems and their associated environmental, social and economic
risks provides the background and contet for wh this is a necessar shift. Movement toward a soft
path for water management through decentralized and distributed-scaled sstems offer alternatives for
communities willing and/or forced to re-think their path forward.
BEST MANAGEMENT PRACTICES FOR DECENTRALIZED WATER SySTEMS
Best management practices (BMPs) for net zero water buildings emphasize closed-loop sstems, ultra-efcientmeasurestoreducesystemdemands,small-scalemanagementsystems,t-for-purposewater
use and diverse, locall appropriate infrastructure. Establishing a water balance (a numerical account of
how much water enters and leaves the boundaries of a project) is a critical step in understanding water
owson-site.Themostsuccessfuldesignstrategiesarethosethatnotonlyseekequalitybetweenwater
supplyvolumeandbuildingdemand,butalsoaddresslongtermnancialandpublichealthrisksand
provide educational opportunities for building occupants.
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Toward Net Zero WaterPage 2
This report contains an overview of best practices for decentralized and distributed water strategies
organized b the following subjects:
Rainwater harvesting, including strategies for potable and non-potable uses
Grewater reclamation and reuse
On-site wastewater treatment and reuse, including composting toilets
Best practices for the design and implementation of on-site stormwater management sstems and for
improvingxtureefcienciesarenotincludedinthescopeofthisreport,thoughareimportantaspectsto
achieving net zero water goals.
Each BMP chapter describes major sstem components, how the sstems work and background on
appropriatescaleandefciency.Additionaldesignconsiderationsaresuggestedforsystemsizing,location
and integration with other building sstems. Case studies of innovative projects from around the globe are
highlighted in each chapter. The additional resources section located at the end of the chapter describes
wheretondmorein-depthinformationandtechnicaldetailsondecentralizedBMPs.
FURTHER RESEARCH
The amount of research and literature available on alternative water sstems is staggering. However, more
comprehensive information and design guidance is needed on balancing available on-site water supplies,
including rainwater and reccled water, with occupant demand. More on-the-ground demonstration
projects also are needed to showcase BMPs and inform future net zero water efforts. Additional research
is needed in the following areas to support and empower the net generation of innovative water projects:
Broader evaluation of public health and safet risks
Lifeccle assessment investigating the environmental impacts associated with various strategies
Chlorine disinfection for treatment of on-site rainwater harvesting sstems
Climate change and resilienc of fresh water supplies
Occupant behavior related to water use in buildings
Presence of pharmaceuticals and other chemicals found in water supplies
Increasing water demands for urban agriculture
An etensive bibliograph of sources uncovered during the literature review is located at the end of the
report and provides a list of references for further research.
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Toward Net Zero WaterPage 2
introduction
Good, qualit water is a diminishing resource. There is growing consensus that the water
crisisacceleratedbypollution,inefcientuseandclimatechangewillsoondwarf
theenergycrisisinsignicanceandseverity.1 Alread, more than 900 million people on
this planet do not have access to safe drinking water, and 2.6 billion are not using safe
sanitation practices.2 As a species, we must generate a health relationship with water if
we want to survive and protect the biodiversit of the planet. Implementation of sustainable
water use will require the combined efforts of regulators, designers and users. This
document is intended to help regulators and designers of urban sstems understand bestpractices for creating water sstems that allow building occupants to reduce the impacts of
their use.
CURRENT CHALLENGES AND OPPORTUNITIES: WATER AND WASTE
Of all the Earths water, 97.5 percent is salt and 2.5 percent is fresh water. Of that fresh
water, onl 1 percent (.007 percent of the total water) is readil accessible for human use.
Sevent percent of the worlds water is used for agriculture, 22 percent for industr and 8
percent for domestic use. In high-income countries like the United States, approimatel
30 percent of our fresh water is used for agriculture, 59 percent for industr and 11 percent
1 Furumai, H. Rainwater and reclaimed wastewater for sustainable urban water use. Phsics andChemistr of the Earth, Parts A/B/C, 2008.
2 Corcoran, E., C. Nellemann, E. Baker, R. Bos, D. Osborn, H. Savelli (eds). 2010. Sick Water? The centralrole of wastewater management in sustainable development. A Rapid Response Assessment. UnitedNations Environment Programme, UN-HABITAT, GRID-Arendal.
Infact,asaspeciesweareapproximately65percentwateritdenesand
shapesusineverywayimaginable,physicallyandspiritually,fromourrstfew
months in the womb, when we are literall enveloped b it, to life outside the
womb, where we need to be constantl replenished with eight to ten cups of clean
water each da to survive.
Jason F. McLennan, CEO, Cascadia Green Building Council
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Introduction Page 3
for domestic use.3 Clearl, reducing demand from the agricultural and industrial sector
should be prioritized for addressing the world water crisis. However, urban water issues
willcontinuetobesignicantinanincreasinglyurbanworld.Asof2009andfortherst
time in histor, more humans live in cities than outside cities. We are an increasingl urban
species, and our water sstems are ever more important as a result.
Here in the United States, we have enjoed a half-centur of nearl universal access to
abundant supplies of potable water. But serious and sustained droughts in the south and
longbitterghtsoverwaterrightsinthewestindicatethisprivilegeisending.Future
population growth will eert more demand on water sstems while climate change is
predictedtodecreaseavailablesupplies.Recently,aGovernmentAccountabilityOfce
(GAO) surve found that water managers in 36 states anticipate water shortages b 2020.
These challenges will require a more sustainable approach to using water resources,
looking at not onl how much water is used but also the qualit of water needed for each
use.4
3 Ten Things You Should Know About Water. Circle of Blue WaterNews. N.p., October 2010.
4 Kloss, Christopher, Managing Wet Weather with Green Infrastructure: Rainwater Harvesting Policies:US EPA, 2008.
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Toward Net Zero WaterPage 4
57%
33%
10%
FIGURE I-3. TyPICAL DAILy WATER USE FOR HOTELS
Source: Kloss, Christopher. Managing Wet Weather with Green Infrastructure: Rainwater Harvesting Policies: US EPA, 2008.
While potable water is used almost eclusivel for domestic uses, Figure I-1 shows
approimatel 80 percent of demand for a tpical residential building does not require
potable water. Similar trends eist for commercial water use. Figures I-2 and I-3 provide
eamples of dail commercial water usage.
FIGURE I-1. TyPICAL DOMESTIC DAILy PER CAPITA WATER USE
Potable Indoor Dail Uses:Showers 11.6 gal.Dishwashers 1.0 gal.Baths 1.2 gal.Faucets 10.9 gal.Other uses, leaks 11.1 gal.
Non-Potable Indoor Dail Uses:Clothes washers 15.0 gal.Toilets 18.5 gal.
58%
21.7%
20.3%
14%
48%
38%
FIGURE I-2. TyPICAL DAILy WATER USE FOR OFFICE BUILDINGS
Potable indoor uses
Non-potable indoor uses
Outdoor uses
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Image:Island
Wood
Students learn about on-site wastewater treatment at IslandWoods Living Machine.
Introduction Page 5
Potablewaterisoftenutilizedforpurposesthatcouldbesatisedwithlower-quality
water,suchastoiletushing,irrigationandlaundry.Statisticsalsoshowthatthevast
majorit of water is used in a one-time, pass-through manner with little attempt at reuse.
Our centralized, big-pipe infrastructure relies on an industrial model of specialization
and economies of scale.5 Though designed and managed primaril to protect the public
frompathogensandoods,thesecentralizedsystemsaretypicallyresourceandenergyintensive in their transport and treatment of water and pose serious social, environmental
and economic risks for urban American communities. Further, these sstems are riddled
withinefcienciesduetotheageandpoormaintenanceofourcitieswaterinfrastructure,
andtheirverydesigncancreateanimbalanceinwaterandnutrientowsthatdistort
hdrological and ecological regimes. According to the 2009 American Societ of Civil
Engineers Report Card, our nations water and wastewater infrastructure scored a D- with
over$255billionneededtofundupgradestothesesystemsoverthenextveyears.
In this time of growing water crisis, it is critical that we re-imagine our water sstems
in which more environmentall, sociall and economicall responsible sstem design
andoperationisconsideredalongwithpublichealthbenets.Reviewofdecentralized
infrastructure with smaller-scale integrated sstems that incorporate rainwater capture,
t-for-useon-sitetreatmentandwaterre-useisalogicalstartingpointforthisre-
imagination. These sstems are the subject of this report, which addresses best practices
for their implementation within U.S. cities that allow or are open to allowing the inclusion of
distributed sstems within the water solution for future sustainabilit.
5 Nelson, Valerie. New Approaches in Decentralized Water Infrastructure. Decentralized WaterInfrastructure, 2008
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Toward Net Zero WaterPage 6
references
Corcoran, E., C. Nellemann, E. Baker, R. Bos, D. Osborn, H. Savelli (eds). 2010. Sick Water?
The central role of wastewater management in sustainable development. A Rapid ResponseAssessment. United Nations Environment Programme, UN-HABITAT, GRID-Arendal. www.
grida.no.
Furumai, H. Rainwater and reclaimed wastewater for sustainable urban water use.
Phsics and Chemistr of the Earth, Parts A/B/C (2008): 340-346.
Kloss, Christopher, Managing Wet Weather with Green Infrastructure: Rainwater
Harvesting Policies: US EPA, 2008.
Nelson, Valerie. New Approaches in Decentralized Water Infrastructure. Decentralized
Water Infrastructure. (2008): 1-79.
Ten Things you Should Know About Water. Circle of Blue WaterNews. N.p., October 2010.
Web. October 2010. (www.circleofblue.org).
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8
11
17
20
SECTIONS
Histor of Centralized Water Sstems
Current Conditions: Environmental, Social & Economic Risks
Moving Forward: A Vision for Net Zero Water
Current Barriers to Net Zero Water
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Toward Net Zero WaterPage 8
History of centrAlized wAter systems
B the mid to late 18th centur, most large U.S. municipalities installed underground fresh
water conveance sstems. Basic stormwater sstems were installed at the end of the 18th
centur, and b the middle of the 19th centur, centralized water-carriage sewer sstems
became the standard over priv vault-cesspool sstems.
The water-carriage sstem solved some problems and created others, especiall in more
densel populated communities. Man cit residents accepted the sanitation problems
and foul odor as an unavoidable part of urban life.6 Open sewers lined the streets and
households cast their biological waste products into the streets below. Cit boosters,
wishing to clean up the urban image and attract both residents and industries, advocated
for centralized waste management and sewer sstems.
Opponents to centralized waste management and sewers argued that a source of fertilizer
would be lost, soil and water supplies would be polluted at the sstem outfalls and that
modern sewer sstems would create and concentrate disease-bearing sewer gas.7
The debate over the design of centralized sstems was split between the argument for
combined sewer sstems versus separated sewer sstems. The combined sewer sstems
used a single pipe to transport both stormwater and wastewater to a designated disposal
location, as opposed to the separated sewer sstems, which required laing two pipes.
Man cities installed combined sstems because the were less epensive to build.
6 Burrian, Steven J., Stephan Ni, Robert E. Pitt, and S. Rock Durrans. Urban WastewaterManagement in the United States: Past, Present, and Future. Journal of Urban Technolog. 7.3, 2000.
7 Ibid.
context And bAckground
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Contet and Background Page 9
It wasnt until late in the 19th centur that the relationship between wastewater and
diseasetransmissionbecamewellunderstood.Waterltrationbecamemorecommonas
studiesdemonstratedthatsandltrationprocessescouldhelplowertheinfectionrate
of waterborne illnesses such as cholera and tphoid. Using chlorine to disinfect drinking
water became prevalent in the earl 1900s. Treatment of wastewater utilizing tanks and
chemicalreactionstolter,settleandbindcontaminantsfoundinwastewaterbecamemore common b 1910-1920. Dewatering techniques were also developed, successfull
producing a b-product sold as fertilizer. As sstems developed in the 20th centur, the
unpredictableowrateofcombinedsewersystemsmadeseparatedsewersystemsthe
preferred choice for treatment plants. Man cities ended up with compound sstems
that included a combined sewer sstem in some districts and a separated sewer sstem in
newer districts. This is the legac of our urban water sstems.
Wastewater treatment became widespread
after the introduction of federal funding
with the Water Pollution Control Act of
1948. The WPC Act provided planning,
technicalservices,researchandnancial
assistance b the federal government to
state and local governments for sanitar
infrastructure. The WPC Act was amended
in 1965, establishing uniform water qualit
standards and creating the Federal Water
Pollution Control Administration authorized
to set standards where states failed to do
so. In 1970 the Environmental Protection
Agenc (EPA) was created.
In 1972, the Clean Water Act was passed
to limit pollution of freshwater sources.
In 1974, the Safe Drinking Water Act
was adopted to regulate public water
systems.Itspeciedwhichcontaminants
must be closel monitored and reportedto residents should those contaminants
eceed maimum allowable levels. Since
the 1970s, federal, state and municipal
governments have closel monitored
American drinking water sstems. For1885ScienticAmericanMagazinefeaturingalargeinfrastructureprojectin New york Cit.
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Toward Net Zero WaterPage 10
decades federal funding for water suppl and sanitation was provided through grants to
local governments. After 1987, the sstem was changed to loans through revolving funds
that have favored big-pipe infrastructure.
Increased water qualit standards and regulation, coupled with advancements in water
treatment and deliver and wastewater disposal sstems, have dramaticall improved
human health in American cities. These sstems have also altered human settlement
patterns b allowing communities to grow beond the carring capacit of their local
eco-sstems as water-on-demand and waste-be-gone sstems became standard.
Thesesystemshaverequiredlargeenergyandnancialinputstomanufacture,installand
operate.Now,thisaginginfrastructureisanancialburdenformunicipalities.
Cities across America must face big decisions about how the will continue to meet the
water and wastewater needs of their growing communities while continuing to protect
public health. The business-as-usual approach is to rebuild and epand the eisting
sstems without considering alternative solutions. In evaluating alternatives, it isimportant to understand the associated environmental, social and economic risks of each
option. As communities risk bankruptc in order to maintain aging infrastructure, prudent
consideration of decentralized and distributed sstems is crucial to help address the
nancialresiliencyofourcommunities.
Centralized water treatment facilit.
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Contet and Background Page 11
current conditions: environmentAl, sociAl &economic risks
Centralized water collection and treatment sstems have greatl improved overall public
healthbyprovidingaccesstoafresh,cleanwatersupply.Despitethesebenets,thescales
andmethodsatwhichthesesystemscurrentlyoperateposesignicantenvironmental,
socialandnancialrisks.
ENVIRONMENTALdp aa h h h ah
The ecological impacts of large dams and water treatment projects have become a growing
environmentalconcern.Disruptingthenaturalowofrivers,streamsandgroundwater
percolation have far-reaching effects on a watersheds ecological health. At its healthiest,
a freshwater sstem maintains a state of dnamic equilibrium, ielding crucial ecological
servicesbyprovidinghabitat,barrierstotoxins,nutrienttransportationandlter
functions.8 To maintain this equilibrium, mechanisms allow the ecosstem to control
eternal stresses or disturbances within a certain range of responses thereb maintaining
a self-sustaining condition.9 Big pipe sstems quickl move large volumes of water from
one watershed to another. This movement can cause the groundwater table to drop at the
source, creating a sstem imbalance. The disruption of a watersheds equilibrium can
consequentl cause high nutrient and pollutant concentrations in areas previousl devoid
of such contaminants, compromising the qualit of the ecological services these sstems
provide.10 Large water infrastructure projects strain the resilience of these comple
watershed sstems, making this ver precious resource vulnerable.
P a a
Most sewer sstems were designed as Combined Sewer Sstems, where wastewater and
stormwaterowintoonepipeontheirwaytobetreated.Itistypicalforsewersystemsto
bedesignedforpeakowloadssothateventhelargeststormwatereventcanbetreated
throughthesystem.However,manyoldercombinedsewersystemsaresubjecttoows
abovetheircapacityduringheavyrains.TheuseofaCombinedSystemOverow(CSO)was
an economical wa to prevent sewage backups into homes and businesses b releasing
overowwastewaterandstormwaterintoadjacentbodiesofwater.11 The CSO is an obvious
8 Federal Interagenc Stream Restoration Working Group (FISRWG) Stream Corridor Restoration;Principles, Processes and Practices. Washington, D.C.: FISRWG, 1998.
9 Ibid.
10 PacicStatesMarineFisheriesCommissionandtheOregonFisheriesCongress,WhenSalmonAreDammed., 04 Apr 1997. Web. 7 Sep 2010.
11 KingCounty.CombinedSewerOverow(CSO).PublicHealth-Seattle&KingCounty.KingCounty,03 Feb 2010. Web. 8 Sep 2010.
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Toward Net Zero WaterPage 12
danger to the health of our waterwas. Due to the rigid infrastructure of the big pipe
system,itisdifculttorespondtotheseuctuationsandconcentrationsofcontaminants.12
The big pipe sstem leaves little room for quick, economical upgrades, as the
infrastructure is a long A to B treatment sstem. With this in mind, change in capacit
over long periods of time can prove problematic. As Rose George eplains in The Big
Necessity, Wet weather discharge is normal. Its how the sstem works, whether people
know it or not. Sewer designers calculate their sstem capacit to cope with storms and
oods.NewYorkssewers,builtindrier,lessgloballywarmedtimes,werebuilttocome
with a maimum of 1.75 inches of rain falling in an hour. But times and the weather have
changed. As we continue to see shifts in rainfall and snowmelt due to climate change,
our sewer sstems capacit to handle increasing loads will be both an environmental and
economic concern.
Hh a, a a aa
According to the US Environmental Protection Agenc (EPA), approimatel 3 percent of ournational energ consumption is used solel for the purpose of providing safe drinking water
and sanitation services. In California, water-related energ use consumes 19 percent of the
states electricit, 30 percent of its natural gas and 88 billion gallons of diesel fuel ever
ear and this demand is growing.13
Currentl the average person living in the United States uses between 65 to 78 gallons
ofwaterperdayfordrinking,cooking,bathing,ushingandyardwatering.14 Though the
need for conservation in our water habits is inarguabl a concern, the means b which we
transport our water in urban areas from suppl sources and to remote treatment facilities
is in need of equal attention. The big pipe sstem has created an etensive network of pipes,
pumps and tanks to accommodate this transportation, all of which need to be maintained.
Overtime,cracksturntoleaksthat,duetothesizeoftheselargesystems,canbedifcult
to locate and repair. The United States suffers about 240,000 water main breaks annuall
and the countr loses approimatel 6 billion gallons a da enough water to suppl the
entire state of California.15 This constant need for maintenance leads to increased water
waste as well as the potential for groundwater and surface water contamination.
12 Slaughter, S. Improving the Sustainabilit of Water Treatment Sstems: Opportunities for Innovation.Solutions. 1.3 2010.
13 California Energ Commission, Californias Water Energ Relationship: Final Staff Report, 2005.
14 PacicInstitute,WaterFactSheetLooksatThreats,Trends,Solutions.,2008.
15 Urban Land Institute, Infrastructure 2010: Investment Imperative. Urban Land Institute, 2010.
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Toward Net Zero WaterPage 14
protection, operator training, funding for water sstem improvements and public
information requirements, ensuring better water qualit.
Contaminants become regulated when the occur in the drinking water suppl and are
considered a threat to public health. There are four tpes of known contaminants that are
tested for which can be broken down into four groups: Microbial Pathogens, Organics,
Inorganics and Radioactive Elements.
Though much has been done to prevent risks of contaminants entering our drinking water,the size and age of our water infrastructure makes the risk of alternate point contamination
difculttoassess.Inaddition,investigationsconductedinthelastveyearssuggestthata
substantial proportion of waterborne disease outbreaks, both microbial and chemical, are
attributable to problems within distribution sstems.
In an effort to improve water qualit deliver, the National Academies Water Science
andTechnologiesBoardhasidentiedwaystoassesstherisksassociatedwiththe
contamination of a large water distribution sstem. These methods include the utilization
of pathogen occurrence data, the surveillance of waterborne disease outbreak, and the
eecution of an epidemiolog stud that isolates the distribution sstem component.
Increased consumption of pharmaceuticals and hormones has led to the presence of
these chemicals in our water stream. In 2008, the American Associated Press investigated
thelevelsofpharmaceuticalsindrinkingwater,ndingthatover46millionAmericans
consume water that tested positive for trace pharmaceuticals. The effects of these trace
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Contet and Background Page 15
pharmaceuticals are not et known as water qualit standards do not currentl test for
them. Research conducted in Europe b poisons epert and biologist Francesco Pomati is
preliminar but warrants further investigation. Pomati eposed developing human kidne
cells to a water miture containing 13 drugs that mimicked the levels in Italian rivers. He
found that cellular growth was slowed b up to one-third the speed of uneposed cells.19
Testing for the presence of pharmaceuticals and more research on the effects of thesemitures is needed.
Hah aaph a
Major catastrophe or malfunction of a big pipe sstem leaves its service population
vulnerable to contamination or without access to potable water. In 1975 a valve failure
combinedwithheavyrainscontributedtorisingoodwatersinTrentonandHamilton
townships in New Jerse, leaving residents with a shortage of water for ten das. Though
heav rains were present, the culprit of the shortage was a simple mechanical failure.
Hurricane Katrinas disastrous legac in New Orleans was accelerated due to thecatastrophic failure of the levee sstem. This severe storm also affected a number of
water sstems in cities across the region. The EPA estimated that more than 1,200 drinking
water facilities and 200 wastewater treatment facilities were affected.20Foroodedareas,
sewage treatment is one of the last services to get back on line, as these plants often eist
in the lowest ling areas. The big pipe sstem offers large solutions to a large population
but when failure occurs, it is time consuming for the sstem to become operational. A one-
point source of treatment also offers one point for concentrated contamination in the event
of a catastrophe.
eq
Waterinfrastructurethatissizedtoaccommodateowcapacitiesprojected20-30years
into the future is costl to a communit. As discussed in the economic section of this
chapter, these high initial costs ma result in a disparit in water qualit depending on a
recipients proimit to the centralized sstem. This disparit could affect the qualit of
communit planning and negativel impact development choices.
d a /a a
The big pipe paradigm moves our water from tap to treatment to tap again with little
user knowledge of what happens in between. The instant deliver of clean water is aconvenience that we take for granted. This convenience also disconnects us from an
19 Donn, Jeff, PHARMAWATER-RESEARCH: Research shows pharmaceuticals in water could impacthuman cells, Associated Press, n.d. Web. 7 Sep 2010.
20 Copeland, C. Hurricane-Damaged Drinking Water and Wastewater Facilities: Impacts, Needs, andResponse, Congressional Research Service, Librar of Congress, 2005.
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Toward Net Zero WaterPage 16
understanding of our watershed sstem and
where our water comes from, also affecting
our understanding about how to best care of
this resource.
ECONOMICcapa paa
The nature of the big pipe paradigm
necessitates large amounts of
infrastructure, which requires increased
maintenance as the sstem ages. Population
growth places additional strain on older
sstems, with increased densit demanding
increased infrastructure in urban andrural areas. According to John Crittenden
of Georgia Tech Universits Brook Bers
Institute for Sustainable Sstems, We
epect in the net 35 ears to double the urban infrastructure, and it took us 5,000 ears
to get to this point. So we better do that right. We better have a good blueprint for this as
we move to the future, so that we can use less energ, use less materials, to maintain the
life that we have become used to.21 The man costs of this increase in infrastructure and
maintenancearebeingconsideredbytheEPA,theGovernmentAccountabilityOfce,the
Water Infrastructure Network and others as the project a wastewater funding gap of $350billion to $500 billion over the net 20 ears.
c a
If the average person living in the United States uses between 65 to 78 gallons per da,
29percentofthishigh-qualitywaterisusedforushingtoilets.22 This means that on a
dailybasis,everyAmericanushesapproximately19gallonsofpotablewaterdownthe
drain. The big pipe sstem is designed to combine all grades of water and to treat it to the
same level regardless of how it will be used. This wa of piping water creates ecessive
waste with economic consequences. With the operational costs for treatment to potable
21 IEEESpectrumPodcasts.DecentralizedWaterTreatmentismoreefcient,exibleandresilient.Web. 7 Sep 2010.
22 Urban Land Institute, Infrastructure 2010: Investment Imperative. Urban Land Institute, 2010.
Up to 80 percent of sstem costs can be attributed to collection and conveance ofwater.
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Contet and Background Page 17
standards being on average $2 per 1,000 gallons, both consumers and producers could be
spending much less b reducing potable water demands. 23
iq & p
High initial costs of big pipe sstems take into consideration the future capacit of the
treatment facilit. Communities that do not have the resources to cover these initial
epenses ma opt to connect onl certain portions of their communit to centralized water,
leaving parts of the population without access to the same standard of clean water. In
addition, the total cost of big pipe sstems ma not be full realized in some areas where
local water is scarce, such as the desert southwest. This misrepresentation of the actual
costofprovidingwatertotheseremoteareascangivetheillusionofabundanceofanite
resource.
moving forwArd: A vision for net zero wAter
The gap between projected demand and funding for drinking water infrastructure has been
estimated b the U.S. EPA to be as much as $267 billion over the 20-ear span between
2000 and 2020. The situation for wastewater infrastructure is similar and Congress is not
expectedtollthisgap.24
In April 1997, the U.S. EPA concluded that decentralized sstems can protect public
health and the environment, tpicall have lower capital and maintenance costs for rural
communities, are appropriate for varing site conditions and are suitable for ecologicall
sensitive areas when adequatel managed.25
Decentralized infrastructure could be second onl to improved agricultural use in
addressingthenationswatersustainabilitychallenges,butchangecanbedifcult.Many
forms of decentralized sstems have long proved to be effective for improving water (and
energ) sstem performance, but recognition of this potential has been slow to gain ground.
Distributed sstems operate at the margins of engineering practice, and construction of
big-pipe infrastructure continues.26
23 US EPA. Funding Decentralized Wastewater Sstems Using the Clean Water State Revolving Fund.Washington, DC: US EPA, June 1999.
24 Etnier, Carl, Richard Pinkham, Ron Crites, D. Scott Johnstone, Mar Clark, Am Macrellis, OvercomingBarriers to Evaluation and Use of Decentralized Wastewater Technologies and Management. London: IWAPublishing, 2007.
25 US EPA, Decentralized Wastewater Treatment Sstems: A Program Strateg. Cincinnati: U.S. EPAPublications Clearinghouse, 2005.
26 Nelson, Valerie. New Approaches in Decentralized Water Infrastructure. Decentralized WaterInfrastructure. 2008.
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Toward Net Zero WaterPage 18
Urban water and waste sstems management has been driven b technological, end-of-
pipe problem solving. The current dominant paradigm has evolved in a stepwise fashion,
andthelongevityandinvestmentnancial,structuralandsocialintothesesystems
has locked man communities into an approach with rapidl diminishing returns. The
compleit of challenges and dnamic nature of modern cities requires an integrated
approach that supports adaptabilit and innovation. Movement toward a soft path forwater management with decentralized and integrated technical sstems and distributed
andexiblemechanismsofcoordinationandcontroloffersawayforwardformany
communities willing or forced to challenge their status quo.
THE WATER PETAL OF THE LIVING BUILDING CHALLENGEThe soft path for water management emphasizes closed-loop
systems,ultra-efcientmeasurestoreducedemand,small-scaled
managementsystems,t-for-purposewateruseanddiverse,locally
appropriate and commonl decentralized infrastructure.27
ThispathwayisreectedintheintentoftheLivingBuildingChallengev2.0sWaterPetal:
TheintentoftheWaterPetalistorealignhowpeopleusewaterandredenewaste
in the built environment, so that water is respected as a precious resource. Scarcit
of potable water is quickl becoming a serious issue as man countries around the
world face severe shortages and compromised water qualit. Even regions that have
avoided the majorit of these problems to date due to a historical presence of abundant
fresh water are at risk: the impacts of climate change, highl unsustainable water use
patterns,andthecontinueddrawdownofmajoraquifersportentsignicantproblems
ahead.
The Living Building Challenge Water Petal includes two imperatives. The primar focus of
this report is on meeting the demands of the Net Zero Water Imperative:
One hundred percent of occupants water use must come from captured precipitation
or closed-loop water sstems that account for downstream ecosstem impacts and
thatareappropriatelypuriedwithouttheuseofchemicals.
This prerequisite requires water sstems to be primaril closed-loop, recirculating water
back to its source for eventual re-draw. This report includes best management practicesand technologies for catchment and use of rainwater, on-site reuse of grewater and on-
site treatment of sewage or blackwater. Case studies provide real-world eamples of how
these distributed sstems have been designed and implemented.
27 Chanan, A., J. Kandasam, S. Vigneswaran, and D. Sharma. A Gradualist Approach to AddressAustralias Urban Water Challenge. Desalination. 249.3. 2009.
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Contet and Background Page 19
The second imperative under the Living Building Challenge Water Petal focuses on
Ecological Water Flow:
One hundred percent of storm water and building water discharge must be managed
on-site to feed the projects internal water demands or released onto adjacent sites
formanagementthroughacceptablenaturaltime-scalesurfaceow,groundwater
recharge, agricultural use or adjacent building needs.
This report addresses on-site wastewater treatment but does not provide best
managementpracticesspecictothedesignandimplementationofstormwatersystems.It
alsodoesnotprovideguidanceforimprovingxtureefciencyorinstitutingotherdemand
management strategies such as real cost pricing or public education. Other topics not
discussed here but ver relevant to the success of these projects include the creation of
regulator environments that allow and incentivize such sstems, and the implementation
of strategies that ensure proper long-term sstem operation.
TheOmegaCenterforSustainableLivinginRhinebeck,NewYork,isoneoftherstprojectscertiedundertheLivingBuildingChallenge.Theprojectisawastewaterltrationfacilitydesignedtoreusetreatedwaterforirrigationandserveasateachingtool for campus educational programs. Image: Farshid Assassi courtes of BNIM Architects
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Toward Net Zero WaterPage 20
TOWARD GREATER EMBRACE OF DECENTRALIZED SySTEMSIn her 2008 article New Approaches in Decentralized Water Infrastructure, Valerie
Nelson offers three steps toward greater embrace of decentralized water sstems:
1. Incorporation of water concerns into the green building movement and funding of
communit demonstration projects.
2. Support for a multi-faceted conversation about sustainable water infrastructure
with public bureaucrats and managers, sstem designers, entrepreneurs, activists
and the public.
3. Serious restructuring of water institutions and policies, including an integration
ofplanning,funding,andregulationsacrossthecurrentlysegmentedeldsof
water, stormwater and wastewater; an epanded role for the private sector in
technologydevelopment,systemsmanagementandnance;acloserlinkbetween
professional practice and communit participation; and careful management andstimulus of continuous innovation and reform.
Nelsonsapproachrequirestheremovalofsignicantregulatory,nancialandcultural
barriers to decentralized sstems.
current bArriers to net zero wAter
A variet of challenges eist for net zero water projects that seek to use best practices
around water conservation, rainwater harvesting, grewater and blackwater reuse indistributed and on-site sstems.
REGULATORy BARRIERSThe compleit of navigating the regulator sstem around such sstems at the local,
state and national levels presents the largest obstacle for project teams seeking approval
for net zero water projects. Currentl, water is regulated across multiple jurisdictions
and agencies: plumbing codes enforced b local or state building departments; local and
state public health agencies regulating water suppl and waste treatment; departments
of environmental qualit and protection regulating stormwater management, reclaimedwater, and on-site wastewater treatment; and wetland and shoreline protection that ma
involve approvals from local, state and national agencies such as the Corps of Engineers.
Some states such as Colorado have water rights laws governing rainwater harvesting,
whileotherssuchasCaliforniaandArizonahaveprovisionsspecictogreywaterreuseor
water-efcientxturesandappliances.
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Contet and Background Page 21
Regulator barriers to net zero water projects stem from the current bias for centralized
water suppl and wastewater treatment and the associated lack of an authoritative bod
with appropriate powers to operate, manage and regulate decentralized approaches.
Particularl in urban and suburban areas where development codes and public health
regulations require connections to public utilities, small-scale decentralized sstems
frequentlylackanyclearlydenedregulatorypathwaysforapprovalsandinsteadrelyonindividualprojectteamswiththewillornancialmeanstonavigatetheregulatory
sstem. Often, the regulations that do eist at the local, state and national levels overlap
orconictwitheachother,andsometimestherearegapswherenoregulatoryprovisions
are currentl in place. Project teams are tasked with a length or costl variance process to
seek approvals for net zero water strategies, costs that are rarel recoverable to a project
team.Furthermore,case-by-caseapprovalsareseldomdocumentedforthebenetof
future projects or to guide future code updates.
Often overlooked are the code and regulator barriers that eist in local land use and
development codes and in covenants, conditions and restrictions (CCR) declarations of
communit associations. For instance, cisterns for rainwater collection sstems can
conictwithsetbackandheightrestrictionsprohibitingtheiruseforretrotapplications
thattendtowardabove-groundstorage.Likewise,landscapingrequirementscanconict
with low-impact development strategies. Such was the case in a communit in Marland
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Toward Net Zero WaterPage 22
where disconnecting downspouts and creating rain gardens to manage stormwater on-site
wasinconictwithregulationsthatrequiredmowingoftheraingardensiftheyexceeda
certainheightlimitationtoavoidmunicipalnesandpenalties.28 Other eamples include
development codes that require connections to municipal utilities as a condition of building
permit issuance, and neighborhood-scale water sstems that cross site boundaries or
public right of was that are often not supported b an codes.
Man regulator agencies are responding to net zero water strategies, though often in
disjointed and incremental was. For eample, the International Association of Plumbing
andMechanicalOfcials(IAPMO)theagencyresponsibleforthedevelopmentofthe
Uniform Plumbing and Mechanical Codes has released a green supplement outlining
voluntaryprovisionsforwaterefciencyandwaterreusestrategiesthatjurisdictionscan
adopt. Additionall, local and state jurisdictions are beginning to open up legal pathwas
for using grewater and rainwater for non-potable uses. But despite these and other
efforts, regulator resistance persists against on-site potable water sources other than
wells, reuse of water for purposes other than subsurface irrigation, non-proprietar on-
sitetreatmenttechnologiessuchasconstructedwetlandsandwaterlessxturessuchas
composting toilets.
In order to create support for net zero water projects, a major shift from our current
regulator framework is necessar. A more holistic approach to regulating water and waste
is needed at all agenc levels in order to support innovative projects and drive future policies.
Muchlikethe1995EnergyPolicyActthatmandatedmaximumowratesforplumbing
xtures,morestringentnationalstandardsareneededtocurbwastefulwaterusebehaviors.
State and local building codes, land use codes and development standards must align tocomprehensivel address on-site water suppl, use, reuse and treatment practices with
clearlydenedrolesandresponsibilitiesforpermitting,operationsandmaintenanceofthese
sstems. Most importantl, water regulations established to protect risks to public health
will need to be assessed and updated to full account for current environmental, social and
economic risks related to centralized water sstems, creating new standards in support of
more integrated water sstems at the site and neighborhood scales.
FINANCIAL BARRIERS
Net zero water projects rel upon on-site or distributed sstems for water suppl andtreatment otherwise managed at the municipal level b publicl-owned utilities. As such,
the cost burden for suppl and treatment sstems as well as their ongoing operation,
maintenance and replacement needs are shifted from the utilit to the individual project
28 Eisenberg, David, Sonja Persram. Code, Regulator and Sstemic Barriers Affecting Living BuildingProjects, Seattle: Cascadia Green Building Council, 2009.
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Contet and Background Page 23
owner.Whilethiscancreatenancialbarriersforprojectowners,uniqueopportunitiesexist
for utilities to develop fee structures and incentives to support the transfer of capital cost,
epense and revenues to offset an owners upfront investment in on-site water sstems. 29
A project owners upfront investments in rainwater harvesting sstems, water-conserving
xtures,dualplumbingforwaterreuse,andon-sitetreatmentsystemscancreate
burdensomenancialbarriers.Evenwhenlifecyclecostsaretakenintoaccount,
articiallylowutilityratesforwaterandwastewaterservicestranslatetolongpayback
periods, since not all utilities use full cost pricing to establish rates for water and
wastewater services.
Full cost pricing factors into account all costs past and future, operations, maintenance
and capital costs into utilit prices and can encourage conservation and reuse strategies
emploed b net zero water projects. Utilities can also utilize alternative pricing structures
to encourage conservation such as block rates that increase the per-unit charge for
services as the amount used or generated increases, or surcharge rates imposed on
above-average water use.30
Robustnancialincentivesatthelocalandstatelevelscanhelpoffsetnancialbarriers
for net zero water projects. Eamples include New york Cits Comprehensive Water Reuse
29 Paladino and Compan, Inc. Onsite Wastewater Treatment Sstems: A Technical Review. Seattle:Seattle Public Utilities, 2008.
30 US EPA. About Water & Wastewater Pricing. Sustainable Infrastructure. US EPA, 08 Apr 2010.
TABLE C-1: TRANSFERRING COSTS AND BENEFITS FROM UTILITy TO OWNER
CAPITAL COSTS ExPENSES REVENUE
Utilit
New central
treatment facilities
Water deliverinfrastructure
Operations and
maintenance
Insurance
User fees
(rates and permits)
Sstem development charges(utilit connection fees)
New connections,
repairs and rebuildsTaes
Costs, Expenses, and Revenue Shifted from the Utility to the Owner
Owner
Onsite treatmentsstem
Dual plumbing
Collection sstems
Operations andmaintenance
Insurance
Reduced water use
and discharge fees,reduced permitting fees
Reduced connection fees
Repairs and rebuilds Grants/incentives
Source: Onsite Wastewater Treatment Sstems: A Technical Review prepared b Paladino & Co. 2008 for Seattle Public Utilities
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Toward Net Zero WaterPage 24
Incentive Program, which provides project owners a 25 percent discount on water services
for reducing demand on the cits infrastructure for water suppl and wastewater services. 31
Likewise, some state agencies offer regulator compliance credits, smaller impact fees
andstreamlinedorsimpliedpermitprocessesforprojectsmanagingstormwateron-site
using low-impact development techniques. While man low-impact development projects
have demonstrated 15-80 percent lower capital costs for project owners in comparison
to conventional methods,32municipalitiescanprovidefurthernancialincentivesthrough
reductions in stormwater discharge fees.
Federalfundingcanalsohelpoffsetnancialbarriersfornetzerowaterprojects.The
American Recover and Reinvestment Act of 2009 provided $4 billion for the Clean Water
State Revolving Fund. Of that, 20 percent of each states capitalization grant can go toward
GreenReserveprojects,whicharedenedasgreeninfrastructure,energyefciency
projects,waterefciencyprojectsorinnovativeenvironmentalprojects.TheU.S.EPA
describes decentralized wastewater sstems as being well positioned for funding underthe Green Reserve projects. In addition, Section 319 of the Clean Water Act provides the
statutor authorit for EPAs Non-point Source Program. According to the U.S. EPA, most
states have non-point source management plans that allow for the use of Section 319
funds for decentralized wastewater sstem projects and decentralized sstem technolog
demonstration projects.33
Financial barriers for distributed water sstems can be directl related to the regulator
barriers noted above. Backup or redundant connections to municipal water and wastewater
utilities ma be required b codes even when a net zero water project is designed
and operated not to use them. Composting toilets sometimes require backup sewer
connectionsandassociatedplumbing,creatinganancialdisincentiveforprojectowners
to even consider their use. Likewise, capacit charges are established b utilities to recoup
sunk costs for large investments in centralized infrastructure projects and are required to
be paid b all building projects located within their service area, regardless of whether or
not on-site sstems can be utilized to meet individual suppl and treatment needs.
Some municipalities have instituted innovative fee structures, such as the Cit of Portlands
Bureau of Environmental Services in Oregon, which allows for emergenc-onl connections
31 Eisenberg, David, Sonja Persram. Code, Regulator and Sstemic Barriers Affecting Living BuildingProjects.
32 US EPA. Reducing Stormwater Costs through Low Impact Development (LID) Strategies and Practices.Washington, DC: US EPA, 2007.
33 US EPA. Funding Decentralized Wastewater Sstems Using the Clean Water State Revolving Fund.Washington, DC: US EPA, June 1999.
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Contet and Background Page 25
to their wastewater treatment facilities but charges large use fees in the event that the
utilit connection is actuall needed.
Removing regulator barriers to decentralized sstems can help spur market innovations
and new products available to designers and homeowners pursuing net zero water
strategies, thus bringing down upfront costs and reducing life ccle cost paback periods.
Foryears,nancialincentivesforenergyefciencymeasuresandon-siterenewables
sstems have been accelerating market adoption of lower energ products and strategies.
The energ sector provides a good eample of how similar approaches can be used to
accelerate advancements in on-site water sstems.
CULTURAL BARRIERSInadditiontoregulatoryandnancialbarriers,publicperceptionsaboutthesafetyofwater
reuseandon-sitewastewatermanagementpresentsignicantobstaclesfornetzero
water projects. Such fears are rooted in our historical management of water and waste
and the resulting public health issues that have surfaced. Previous generations suffered
greatl from tphoid fever, cholera and dsenter until laws and regulations were passed to
support water-carriage removal of waste from urban areas.34 Toda, education is needed to
assure the public of the safet of modern decentralized water sstems and inform them of
theirenvironmental,socialandeconomicbenets.
Thanks to a histor of disease outbreaks, coupled with marketing efforts b earl
ushtoiletmanufacturers,ushingitawayiswidelyviewedasmorecivilizedand
advanced than an other solution for dealing with our water and waste. On-site sstems
are reminiscent of stepping backwards in time and technolog to a less developedage. Education and awareness building among regulators, designers, engineers and
building occupants is necessar to full highlight the environmental risks associated
with wasteful practices. Water that has been treated for drinking purposes, requires
large inputs of energ to be conveed to buildings, contaminated with human ecrement,
conveed awa again and treated with energ-intensive processes that release polluted
water back into the environment does not represent our best technological advancements.
Addressing cultural barriers around decentralized water sstems requires a shift in the
fundamental was in which we view water and human waste. Instead of the current out of
site, out of mind thinking, we need to take ownership not onl of how we use water inside
our buildings and for irrigation, but how we operate, maintain and replace on-site sstems
over time. In doing so, we will treat water as the precious resource that it is.
34 Burrian, Steven J., Stephan Ni, Robert E. Pitt, and S. Rock Durrans. Urban Wastewater Managementin the United States: Past, Present, and Future. Journal of Urban Technolog. 7.3 (2000): 33-62
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Toward Net Zero WaterPage 26
references
Burrian, Steven J., Stephan Ni, Robert E. Pitt, and S. Rock Durrans. Urban Wastewater
Management in the United States: Past, Present, and Future. Journal of Urban Technolog.
7.3 (2000): 33-62.
California Energ Commission, Californias Water Energ Relationship: Final Staff
Report, (2005): 1-180.
Copeland, C. Hurricane-Damaged Drinking Water and Wastewater Facilities: Impacts,
Needs, and Response, Congressional Research Service, Librar of Congress, 2005: 1-6.
Chanan, A., J. Kandasam, S. Vigneswaran, and D. Sharma. A Gradualist Approach toAddress Australias Urban Water Challenge. Desalination. 249.3 (2009): 1012-16.
Disinfection B-ProductsTrihalomethanes. Wilkes Universit Center for Environmental
Qualit Environmental Engineering and Earth Sciences. Wilkes Universit, n.d. Web. 7 Sep
2010. http://www.water-research.net/trihalomethanes.htm.
Donn, Jeff, PHARMAWATER-RESEARCH: Research shows pharmaceuticals in water
could impact human cells, Associated Press, n.d. Web. 7 Sep 2010. http://hosted.ap.org/
specials/interactives/pharmawater_site/da1_03.html
Drinking Water Chlorination. Health Living. Health Canada, 14 Dec 2006. Web. 7 Sep
2010. http://www.hc-sc.gc.ca.
Eisenberg, David, Sonja Persram. Code, Regulator and Sstemic Barriers Affecting Living
Building Projects, Seattle: Cascadia Green Building Council, 2009. (2010): 1-90.
Etnier, Carl, Richard Pinkham, Ron Crites, D. Scott Johnstone, Mar Clark, Am Macrellis,
Overcoming Barriers to Evaluation and Use of Decentralized Wastewater Technologies and
Management. London: IWA Publishing, 2007.
Federal Interagenc Stream Restoration Working Group (FISRWG) Stream CorridorRestoration; Principles, Processes and Practices. Washington, D.C.: FISRWG, 1998.
Health Canada. Drinking Water Chlorination. Website. www.hc-sc.gc.ca/hl-vs/ih-vsv/
environ/chlor-eng.php.
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Contet and Background Page 27
IEEESpectrumPodcastsDecentralizedWaterTreatmentismoreefcient,exibleand
resilient.. Web. 7 Sep 2010. http://spectrum.ieee.org/podcast/green-tech/conservation/decentralized-water-treatment-is-more-efcient-exible-and-resilient.
KingCounty.CombinedSewerOverow(CSO).PublicHealth-Seattle&KingCounty.
King Count, 03 Feb 2010. Web. 8 Sep 2010. http://www.kingcount.gov/healthservices/
health/ehs/toic/cso.asp.
Nelson, Valerie. New Approaches in Decentralized Water Infrastructure. Decentralized
Water Infrastructure. (2008): 1-79.
PacicInstitute,WaterFactSheetLooksatThreats,Trends,Solutions.,2008.Web.7Sep
2010 http://www.pacinst.org/reports/water_fact_sheet.
PacicStatesMarineFisheriesCommissionandtheOregonFisheriesCongress,When
Salmon Are Dammed., 04 Apr 1997. Web. 7 Sep 2010. http://www.psmfc.org/habitat/
salmondam.html.
Paladino and Compan, Inc. Onsite Wastewater Treatment Sstems: A Technical Review.
Seattle: Seattle Public Utilities, 2008.
Slaughter, S. Improving the Sustainabilit of Water Treatment Sstems: Opportunities for
Innovation. Solutions. 1.3 (2010): 42-49. http://www.thesolutionsjournal.com/node/652.
Urban Land Institute, Infrastructure 2010: Investment Imperative. Urban Land Institute,
(2010): 1-90.
US EPA. About Water & Wastewater Pricing. Sustainable Infrastructure. US EPA, 08 Apr
2010. Web. 8 Sep 2010. http://water.epa.gov/infrastructure/sustain/about.cfm.
US EPA, Decentralized Wastewater Treatment Sstems: A Program Strateg. Cincinnati:
U.S. EPA Publications Clearinghouse, 2005.
US EPA. Funding Decentralized Wastewater Sstems Using the Clean Water State RevolvingFund. Washington, DC: US EPA, June 1999.
US EPA. Reducing Stormwater Costs through Low Impact Development (LID) Strategies and
Practices. Washington, DC: US EPA, 2007.
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Toward Net Zero WaterPage 28
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30
34
36
37
41
SECTIONS
Integrated Water Management
FitandEfciency
Communit Involvement
Risk Management
Beaut and Inspiration
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Toward Net Zero WaterPage 30
best mAnAgementPrActices
This document provides guidance for teams pursuing net zero water projects and offers
insight to regulator bodies seeking to better understand and evaluate the net zero projects
that come across their permitting desks. Central to the success of these sstems is an
integratedapproachtotheirdesignandcarefulconsiderationofeachsystemstand
efciency,wheretisdenedastheadaptationofthesystemtoconditionsonordesiredat
thesite,andefciencyisdenedasthesystemsabilitytodelivermaximumperformance
atminimumcost.Thisperformanceisgaugednotonlybynancialreturnoninvestment,
butalsobylifecyclecostsandbenets.
integrAted wAter mAnAgement
In The Logic of Failure: Recognizing and Avoiding Error in Complex Situations, Dietrich Dornereplains, . . . in comple situations we cannot do onl one thing. Similarl, we cannot
pursue onl one goal. If we tr to we ma unintentionall create new problems.
In dealing with comple sstems, it is important to take an integrated or sstems thinking
approach.Systemsthinkingreferstodeningasystemsboundariestoadequately
encompasssignicantcausalrelationshipsandunderstandtheinterconnectionsamong
resources and activities within that sstem. Advantages of decentralized options are often
onl apparent when taking a more integrated approach. For eample, on-site reuse of
grewater can provide a partiall drought-resistant source of landscape irrigation. 35
An integrated or sstematic approach to water sstem design gears all water-related
activities to one another, thereb recognizing the interconnected nature of water and
35 Etnier, Carl, Richard Pinkham, Ron Crites, D. Scott Johnstone, Mar Clark, Am Macrellis, OvercomingBarriers to Evaluation and Use of Decentralized Wastewater Technologies and Management. London: IWAPublishing, 2007.
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Best Management Practices Page 31
wastewater sstems and allowing a concurrent evaluation of a whole sstems potential
costsandbenets.Augmentingexistingresourcesthroughrainwaterharvest,managing
demandviaxtureefcienciesandotherconservationstrategies,re-useofwaterprior
to its release back into a larger sstem and on-site management of stormwater and other
landscapeconcernsallneedtobeaddressedintandem,asthereisbutanelineof
distinction between them.
36
An integrated approach is necessar when attempting to create net zero water projects
with closed-loop sstems where all of the water used on a project is being captured,
treated, used/reused and released on-site. In this report, rainwater harvest and
wastewater treatment and reuse are organized into separate chapters, and stormwater and
other landscape concerns are minimall addressed. This is simpl a wa to organize the
information and is not intended to impl that the related design processes are separate or
unrelated endeavors. To the contrar, an integrated approach is the single most important
process to be understood when considering the best practices for designing a water sstem
as part of a larger integrated design or process for an entire project.
ESTABLISHING WATER BALANCEA water balance is a numerical account of how much water enters and leaves a site. A
water balance sheet should contain detailed information about the amount of water used b
each process. The water balance is a crucial instrument to understand and manage water
owsthroughouttheplant,toidentifyequipmentwithwater-savingopportunitiesandto
detect leaks.37 For a net zero water project, the amount of water entering and leaving a site
shouldideallyreectthenaturalhydrologyofthesite.
Bruggen and Braecken offer a step-b-step method to optimize the water balance, in
three steps:
1. Investigate the current water balance in detail.
2. Combine water consuming processes and reuse water where possible for other
purposes requiring a lower water qualit.
3. Regenerate partial waste streams and re-introduce them into the process ccle.
Figure B-1 provides an overview of the multiple pathwas design teams ma choose to takein establishing a water balance.
36 Buehrer, Mark. 2020 ENGINEERING. Bellingham, Washington. 1996.
37 Van der Bruggen, B., and Braeken L. The Challenge of Zero Discharge: from Water Balance toRegeneration. Desalination. 188.1-3, 2006.
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treatment+reuse
USESOURCE
COMPOSTINGFIXTURES
EXTERIORUSE
TREATMENT+REUSE
2
1
GROUND WATER
RAINWATER
ONSITE RECLAIMEDWATER
OFFSITE RECLAIMEDWATER
MUNICIPAL WATER
SURFACE WATER /STORM WATER
WATER
WATER
BATH/SHOWER
DRINKING FOUNTAIN
LAVATORY SINK
LAUNDRY
KITCHEN SINK
DISHWASHER
FIRE SUPRESSION
PROCESS WATER/HVAC
HIGH EFFICIENCY TOILET (HET)
TOILET WITH URINE SEPARATION
HIGH EFFICIENCY URINAL
WATERLESS URINAL
MICROFLUSH
COMPOSTING TOILET
EXTERIOR WATER USE/IRRIGATION
HET
PREFERRED
POSSIBLE
QUALITy OF WATER
POTABLE:
Water suitable fordrinking
NON-POTABLE:co-mingled water fromushtoiletsandurinals
NON-POTABLE:water from bathroomsinks shower, bathtub,laundr
NON-POTABLE:water from kitchen sinksand dishwashers
NON-POTABLE:urine onl,nutrient rich water
NON-POTABLE:waterfromushtoiletswith urine separation
FIGURE B-1. DESIGNPATHWAyS TO NETZERO WATER
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Best Management Practices Page 33
REUSETREATMENT OUTFLOW
MEMBRANE
BIOREACTOR
CONSTRUCTED WETLANDS/
LIVING MACHINE
POTABLE
NON-POTABLE
INSIDE IRRIGATION
OUTSIDE SUBSURFACE
FOOD CROP IRRIGATION
OUTSIDE SUBSURFACE
LANDSCAPE IRRIGATION
DRAINFIELD
quality A
quality B
AQUIFER RECHARGE
AGRICULTURE
FERTILIZER
COMPOSTING UNIT
RECEIVING
WATER BODY
LIQUID
COMPOST
BIOFILER
OTHER
OFF-SITE TREATMENT
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Imag
e:Perkins+Will
Toward Net Zero WaterPage 34
fit And efficiency
Designers face the challenge of choosing the right water sstem, at the right place, at the
rightmomentandtherightscale.Awatersystemhastoconsiderallimpactedowsand
account for environmental, social and economic risks associated with the sstem, both
on and offsite. Flows include rainwater, stormwater, groundwater, drinking water andwastewater.Inaowsperspective,owsshouldtinachain-managementapproach,
from cradle to grave or, even better, from cradle to cradle.38 It is critical to make the
upstream,on-siteanddownstreamowsttogetherinahealthyclosedloop.
CLIMATERegional climate is a major consideration when choosing and sizing a projects water
system.Forexample,inthePacicNorthwest,therearesomeareasthatreceiveas
much as 140 inches of precipitation per ear. However, those same areas receive nearl
noprecipitationfromJulythroughSeptember.AcrosstheUnitedStates,therearevedifferent major climate zones and sizable variabilit within those zones.39
38 United Nations Environment Programme, Ever Drop Counts: Environmentall Sound Technologies forUrbanandDomesticWaterUseEfciency.Delft:UNEP,2008.
39 US Energ Information Administration. U.S. Climate Zones for 2003 CBECS. Independent Statisticsand Analsis. US Energ Information Administration, n.d. Web. 8 Sep 2010
The Center for Urban Waters in Tacoma, WA, harvests rainwater in t wo 36,000-gallon above ground cisterns.
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Further, the warming of the climate due to human and non-human causes is alread
impactingweatherpatternswithineachzone,andisexpectedtosignicantlyand
progressivel alter precipitation patterns across the United States in the coming decades.
An ecess or lack of water with the change of precipitation patterns ma present the
greatest hazard we face in building durable buildings and communities.
It is also important to consider the microclimatic conditions on the project site itself. The
macroclimate, or long-term weather conditions for a region, is derived from accumulated
da-to-da observations often made at weather stations far awa from the towns and
citieswheremostbuildingsareconstructed.Signicantclimaticvariationscanoccurover
distancesofonlyafewmiles,makingitimportanttounderstandthespecicconditions
present and likel to evolve on the site when making design decisions. Some of the main
factorsinuencingthemicroclimateofasiteare:urbanheatisland,topography,terrain
surface (natural or manmade), vegetation and obstructions.40
Finall, it is important to consider that climate not onl impacts the availabilit ofprecipitation or groundwater for use. The amount of water required b humans and other
actors within a given climate varies enormousl depending on environmental and climatic
conditions such as temperature and humidit.
FIT-FOR-USEThe vast majorit of the water used in the U.S. is drawn from freshwater supplies of
surfaceandgroundwaterthentreatedtopotablestandardsasdenedbytheSafeDrinking
Water Act. A large multifamil or commercial building can use more than 120,000 gallons
of potable water in a single da.41
Once used, the water is tpicall released as wastewater.Accesstothistreatedwaterhasgreatlybenetedpublichealth,butitalsohasresultedin
a sstem that utilizes potable water for virtuall ever end use, even when lesser qualit
waterissufcient.Inadditiontoconservationmethods,usingandre-usingalternative
sourcesofwaterwillbenecessaryformoreefcientuseofwaterresources.42
Treatment of water is a collective term for methods of improving the water qualit b
phsical, chemical and/or biological means. The level of water treatment should be
determined b the intended use or destination of the water. It is wasteful and not necessar
tousepotablewaterforactivitiessuchasushingtoiletsorirrigatingplants.Untreatedor
minimallytreatedrainwatercanbeusedforactivitiesincludingtoiletushing,irrigation,
40 Sharples, Stephen, and Hocine Bougdah. Environment, Technolog and Sustainabilit. New york:Talor & Francis Group, 2010.
41 yeang, Ken. Ecodesign: A Manual for Ecological Design. London: Brook House, 2008.
42 Kloss, Christopher, Managing Wet Weather with Green Infrastructure: Rainwater Harvesting Policies:US EPA, 2008.
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Toward Net Zero WaterPage 36
showeringandlaundry.Greywaterfromxtureslikelavatorybasinsorwashingmachines
can be reused directl in the building, often without treatment or with onl primar
treatment.
FIT-FOR-SCALE
Thewatersystemalsomusttwiththescaleofuse.Differenttechnologiesandstrategieslend themselves to different scales of use. This report addresses three basic scales in an
urban contet: the single famil home, multifamil residential or commercial buildings,
and a neighborhood or campus. There is great diversit even within each of these individual
typologies,emphasizingtheneedforsite-specicdesign.
As suggested in the Living Building Challenge, the appropriate scale for a water sstem
ma etend it beond the boundaries of the project site.
Depending on the technolog, the optimal scale can var when considering
environmentalimpact,rstcostandoperatingcosts.43
The scale of the sstem can impact the scope and boundaries of a risk assessment for
the project. Sstems that go beond a project boundar also naturall epand the role of
communit involvement during the planning phase.
community involvement
Water sstem proponents should decide on the appropriate level of communit
participation to include in the planning stages of the project. The primar audiencefor engagement would logicall include communit members that are the intended
beneciariesofthesystem,alongwiththosethathavethegreatestexposuretoresidual
risk associated with the sstem or whom might be otherwise impacted.
Multiple models eist for varing levels of communit involvement in planning local
projects and infrastructure. These levels range in intensit from consultation to
involvement to engagement. Consultation implies onl providing information to
a communit and requesting feedback. Involvement implies the need for the water
sstem to be responsive to the communits needs, and that the project leaders should
decide on the structures and decision-making processes in which to involve communit
members. Engagement, the most intensive form of communit participation, builds a full
collaborative relationship with a communit for both governance and sstem planning. A
43 McLennan, Jason, Eden Brukman. Living Building Challenge 2.0: A Visionar Path to a RestorativeFuture. Seattle: International Living Building Institute, 2009.
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project team will decide on the appropriate level of communit participation based on the
scale of the project.
In addition to seeking communit input, the project team should communicate earl and
oftenwithstateandlocalgovernmentofcialsandregulators.Theprojectteamshould
discusstheproposalandplanswiththerelevantofcialsandregulatorsasearlyaspossibleintheprojecttoensurethatallissuesareidentiedandaddressedpriortothe
design and permitting stages.
risk mAnAgement
The design of a net zero water sstem is intended to help address and mitigate the large-
scale impacts associated with energ-intensive centralized sstems. Of course, net zero
water sstems also epose users and communities to potential risks. These risks should
be viewed in a broader sustainabilit contet than that often used b the regulator
communit.
Man in the building regulator communit continue to view green and sustainabilit
goals as either tring to maneuver their wa around minimum code requirements or as
optional goals that etend beond their regulator scope of concern or responsibilit.
Meanwhile, the green building movement and . . . the Living Building Challenge
encompassesasignicantlymorecomprehensiveunderstandingofrisk.Inherentin
theirapproachesistheaimoftakingresponsibilityforbalancingthefullriskprolesof
built projects including all the current regulator concerns while simultaneouslseeking to address large, but currentl unregulated risks to present and future
generations and to essential ecological integrit.44
Net zero water projects must address social, environmental and economic risks that are
endemictoallwatersystemsandsomethatarespecictodistributedsystems.Arisk
management framework is the most effective wa to assure the appropriate qualit of
water for the proposed end use. Decisions concerning the scope and boundaries of the risk
assessmentmaybebasedonoperational,technical,nancial,legal,social,environmental
or other criteria. Criteria ma also be affected b the perceptions of stakeholders and b
regulator requirements. It is important to establish appropriate criteria at the outset that
correspond to the tpe of risks and the wa in which risk levels are epressed.
44 Eisenberg, David, Sonja Persram. Code, Regulator and Sstemic Barriers Affecting Living BuildingProjects, Seattle: Cascadia Green Building Council, 2009.
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Theriskassessmentprocessshouldbeginwithdeningtheextentofthewatersystem
andorganizingitintoalogicalframeworkthathelpsensurethatsignicantrisksarenot
overlooked.Theprojectteamshouldconstructaowdiagramshowingallofthestepsin
the sstem from source to end use that includes:
All steps of the process, both within and outside the control of the project team
Source(s) of water
Proposed sstem components
Proposed end uses
Residuals produced from the sstem
Unintended or unauthorized end uses
Discharges or releases to the environment
Receiving environment and/or routes of eposure
An additional considerations needed to maintain the qualit and/or safet of the water
Theowdiagramshouldbesignedoffforauthenticityandstatusbytheteamleader.45
Oncethecontextofthesystemisestablishedwithaowdiagram,simpleriskassessment
matrices are available for prioritizing hazards and identifing the tolerable level of risk
eposure. Risks to be considered can be grouped under three basic categories: social risk,
environmentalriskandnancialrisk.
SOCIAL RISKThe provision of safe water and sanitation has been more effective than an other public
service in promoting public health. Distributed water sstems should be designed and
operated without jeopardizing public health gains achieved historicall via the adoption
of centralized deliver and treatment. Of greatest concern with the use of decentralized
sstems is the associated health risk, especiall the risk of eposure to microbial
pathogens and chemicals-of-concern potentiall present in rainwater and reccled water.
Table B-1 lists potential hazards that ma be present in water before, during or after
treatment. In addition to those presented in the table, trace constituents including caffeine,
estrogen and other hormones have also been detected in the United States.
Health risks can be mitigated with appropriate preventive measures that place barriers
between the rainwater/reccled water and members of the communit. Eamples of
preventive measures include water source protection46, water treatment, protection and
45 Adapted from New South Wales, Department of Water and Energ. Interim NSW Guidelines forManagement of Private Reccled Water Schemes. 2008.
46 Source protection ma include protecting rainwater from animal and human waste and controlling thequalit of water discharged into grewater sstems.
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TABLE B-1: LIST OF POTENTIAL HAZARDS IN RECyCLED WATER
Adapted from the Australian Guidelines for Water Recycling, 2006.
POTENTIALHAZARD
DESCRIPTION
Biological
Algae Simple chlorophll-bearing plants, mainl aquatic & microscopic in size. Under suitable conditions, some
tpes of algae ma grow in untreated or partiall-treated wastewaters, producing algal toins such asmicrocctins, nodularins, clindropermopsin & saitoins.
Bacteria Unicellular micro-organisms tpicall smaller than 5 microns. Bacteria common to blackwater includepathogens such as Camplobacter, Salmonella, Clostridium, & Legionella.
Helminth An invertebrate that is parasitic to humans & other animals. Helminths include tapeworms, roundworms&ukes.
Protozoa A phlum of single-celled animals tpicall ranging in size from around 1 to 300 nanometers.
Viruses Molecules of nucleic acid ranging in size from 20 to 300 nanometers that can enter cells & replicate inthem. Some common viruses found in untreated blackwater include norovirus & enterovirus.
Phsical
Hpoia Ogen depletion brought about b the bacterial breakdown of organic matter in the water.
pH An epression of the intensit of the basic or acid condition of a liquid.
Screenings The solid waste collected in the inlet screens to a treatment process including solids disposed of towastewater.
Suspended solids Suspendedsolidsmeasuresthepresenceofnesuspendedmattersuchasclay,silt,colloidalparticles,plankton & other microscopic organisms.
Chemical
Ammonia Ammonia dissolves rapidl in water & is a food source for some microorganisms, & can support nuisancegrowth of bacteria & algae. Ammonia can be a pollution indicator as it can formed as an intermediateproduct in the breakdown of nitrogen-containing organic compounds, or of urea from human or animalecrement.
Chloride Chloride comes from a variet of salts (including detergents) & is present as an ion (Cl-). Chloride isessentialforhumans&animals,contributingtotheosmoticactivityofbodyuids.However,itcanbetoxicto plants, especiall if applied directl to foliage or aquatic biota.
Disinfection b-products
Disinfection b-products are formed from the reactions bet ween disinfectants, particularl chlorine, &organic material. Chlorine reacts with naturall occurring organic components or ammonia to product b-products such as dicholoroacetic acid, trichloroacetic acid & THMs & chloramine b-products.
Metals Heav metals, such as cadmium, chromium, & mercur ma be present in raw wastewaters as a result ofindustrial discharges.
Pesticides Pesticides harmful to humans & a wide range of species ma enter water sstems b a variet of meansincluding stormwater runoff, personal use & illegal disposal.
Pharmaceuticals Pharmaceuticals & their active metabolites are ecreted b humans &/or disposed of direc tl into watersstems.
Total dissolvedsolidsTotal dissolved solids (TDS) include dissolved inorganic salts & small amounts of organic matter. Claparticles, colloidal iron & manganese oides & silica ma also contribute to TDS. Major salts in reccledwaters ma include sodium, magnesium, calcium, carbonate, bicarbonate, potassium, sulphate &chloride.
Total nitrogen An important nutrient found in high concentrations in reccled waters, or iginating from human &domestic wastes. In high concentrations can cause off-site problems of eutrophication of receiving bodies.
Total phosphorus Originating mainl from detergents but also from other domestic wastes, in high concentrations cancause eutrophication of receiving bodies.
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maintenance of distribution sstems and storages47, restrictions on the distribution and use
of reccled water48, and education of end users.
The most common and effective barrier used is treatment of the captured or reccled water
before use. The level of treatment and disinfection depends on the source of the reccled
water, the potential for fecal contamination and potential for eposure to communit
members, which is generall determined b its intended use and release back into the
environment (See Fit-for-use above).
Beond the more immediate health considerations, other social risks to address include
the sstems ease of operation and maintenance over its lifetime.
ENVIRONMENTAL RISKThere are a variet of environmental risks associated with an water sstem, including
distributed sstems. These include the lifeccle impacts of the sstems component parts,
theimpactsofthesystemonsiteanddownstreamowsandwaterquality,andtheenergyrequired for the construction and operation of the sstem, including an pumping and
treatment process.
The pipe and pumping requirements to conve wastewater from its point of generation to
itspointoftreatmenthassignicantenvironmentalimpacts.Lifecycleanalysisofthese
conveance sstems point toward greater environmental impacts as the length of pipe
and the number of pump stations required increases. Sstems where a series of pump
stations are used to conve wastewater across elevation changes consume large amounts
of energ. Conclusions can be drawn to the etremel important role of service area
topograph in assessing the feasibilit of smaller-scale distributed sstems.49
FINANCIAL RISKFinancial assessment of the long-term viabilit and sustainabilit of a water sstem is
important. According to the 2004 Valuing Decentralized Wastewater Technologies report
prepared b the Rock Mountain Institute for the U.S. EPA, decentralized and distributed
systemscanbemoreexibleinbalancingcapacitywithfuturegrowth.Insmaller-scale
sstems, capacit can be built house-b-house, or cluster-b-cluster, in a just in time
47 Eamples of protection and maintenance of distribution sstems and storages include buffer zones,minimizinglighttorestrictalgalgrowth,maintainingdrainage,andbackowpreventionandcross-connection control.
48 Preventive measures that restrict the distribution and use of reccled water include: signage andcolor coding of pipes; buffer zones; control of access; control of method, time and rate of application; usercontrolled diverter switches; hdraulic loading and interception drains; management plan; prohibition ofrecycledwaterinspecicareas.
49 Cascadia Green Building Council, Clean Water, Health Sound: A Life Ccle Analsis of WastewaterTreatment Strategies in the Puget Sound Area, in progress (2011)
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fashion. This means that the capital costs for building future capacit is spread out over
time, reducing the net present value of a decentralized approach and resulting in less debt
to the communit as compared to the borrowing requirements of a large up-front capital
investment. This is especiall true in the event that a communit sees less growth than
anticipated in their ini