1

Performance of Decentralized Wastewater Systems for Green Building Projects in North America and Australia

Eric Lohan1, Pete A. Muñoz 2, Geoff Salthouse3, Colin Fisher4, Kristina Reid Black1 1Living Machine Systems, L3C, Charlottesville, VA, USA

2Natural Systems International, Santa Fe, NM, USA 3Orenco Systems, Inc., Sutherlin, OR, USA

4Aquacell, Penrith, Australia

Abstract: Within the green building community, water efficiency and the reuse of rainwater and stormwater have been widely embraced. Recent research has demonstrated that wastewater reuse is the single most important, and sustainable, untapped source of water throughout the world for nonpotable applications and this approach has been rapidly adopted in other areas. In the US and Canada adoption has been slow for a variety of reasons, but we review a growing portfolio of successful projects, that demonstrate how this approach can save, water, energy and significant cost. Project and performance data were collected from 25 decentralized treatment and reuse projects in North America and Australia. Excellent tertiary level treatment performance was found despite wide variations in influent concentrations. Four case studies are presented which explore project history, project goals, treatment design and lessons learned including a green commercial development in Sydney, an Ecovillage in Queensland, a landmark stadium in Guadalajara Mexico, and a US Marine Corp base in San Diego. Conclusions and recommendations drawn from survey information, case studies, and working experience are presented regarding cost/benefit, aesthetics, economics, regulations, operations, politics, and nutrient reuse.

(Keywords: water reuse, wastewater treatment, on-site, decentralized)

INTRODUCTIONWater and energy are widely recognized as the critical resources for future sustainability. Within the green building community water efficiency and the sustainable management and reuse of rainwater and stormwater has been widely studied and embraced (Hatt et al. 2006, Holman-Dodds 2007, Cook 2007, Echols 2007, Bradford and Denich 2007, Leatherman 2009, Lynch et al. 2010). Due to climatic and/or population densities, rainwater and stormwater reuse is predicted to have only limited impact on municipal water use in most parts of the world. Recent research has found that wastewater reuse is the single most important, and sustainable, untapped source of water throughout the world (2030 Water Resources Group 2009).

While centralized municipal wastewater treatment and reuse has been effectively employed for decades the EPA currently estimates a $600 billion shortfall in funding for the maintenance and replacement of centralized water and wastewater infrastructure. This suggests that further expansion of these facilities is unlikely. Gikos and Tchobanglous (2010) argue that factors such as centralized capacity limitations, increased urban and periurban populations, water shortages due to global climate change, sustainability concerns, homeland security

concerns, as well as short and long term economic factors will spur the growth and adoption of decentralized treatment and reuse. A growing number of projects and studies are already looking at the benefits of graywater treatment and reuse for commercial projects (Goddard 2005, Li et al. 2008, Anning 2009). At present only a few investigators are proposing or documenting decentralized treatment or reuse of wastewater (blackwater) particularly in urban areas (Gikos and Tchobanglous 2010, Gavasci et al. 2010, Lohan and Kirksey 2011). This paper will review treatment performance of decentralized treatment and reuse for green building projects in North America and Australia.

TREATMENT PERFORMANCE SUMMARY Project and performance data were collected from 25 treatment and reuse systems (Table 1, Table 2). Geographic areas surveyed were limited to North America (Continental US and Hawaii, Mexico, Canada) and Australia, but represent a spectrum of different climates as well as urban, suburban, rural, and remote project sites. Project applications include schools and institutions, stadiums, convention and retreat centers, residential developments, commercial developments and office buildings, as well as animal shelters and zoos. The majority of systems are

2

treating domestic wastewater (gray + black), but a couple treat graywater or effluent from zoo exhibits. All treatment and reuse is for non-potable applications and includes irrigation (60%), toilet flushing (44%), groundwater recharge (12%), wash water (12%), cooling towers (16%), laundry, fire suppression, and animal exhibits.

Information compiled is representative of decentralized treatment and reuse, but is by no means

exhaustive. Many other successful systems are in operation.

A variety of different treatment technologies are represented including membrane bioreactors from Aquacell and GE, recirculating textile filters from Orenco Systems Inc., proprietary tidal flow wetland treatment systems from Living Machine Systems, as well as innovative wetland designs using non-proprietary processes by Natural Systems International.

Table 1: Review of current decentralized systems

Project Location Design Commis-sioned

System Size (lpd)

Wastewater Source Reuse or Disposal

Blacktown Workers Sports Club Sydney Australia Aquacell 2006 100,000 Domestic Surface Irrigation

(spray)

Vinosa Apartments Prince Henry Little Bay SydneyAustralia Aquacell 2007 9,500 Greywater Toilet Flushing, Laundry

1 Bligh St Sydney SydneyAustralia Aquacell 2011 100,000 Domestic Toilet Flushing, Cooling

Tower

Solaire Apartments New York Alliance Envi-ronmental 2003 95,000 Domestic Toilet Flushing, Irriga-

tion, Cooling Towers

Oregon Health Sciences University Oregon Interface Engi-neering 2006 115,000 Domestic

Toilet Flushing, Irriga-tion, Cooling Towers,

Fire Suppression

Dockside Green Community Victoria, BC Aqua-Tex Sci-enti!c 2007 200,000 Domestic Toilet Flushing, Irriga-

tion

Vancouver Convention and Exhibit Centre Vancouver, BC Stantec Consult-ing, Ltd 2008 75,000 Domestic Toilet Flushing, Irriga-

tion

Sidwell Friends School WashingtonDC NSI 2006 11,500 Domestic Toilet Flushing

Omnilife Stadium GuadalajaraMexico NSI 2010 75,000 Domestic Toilet Flushing, Irriga-

tion, Washwater

Willow School New Jersey NSI 2005 7,500 Domestic Groundwater Recharge

Woodland Park Zoo - Penguin Exhibit Washington NSI 2009 11,500 Animal Waste Reuse in Exhibit Pool

Guilford County Northern Middle + High Schools North Carolina LMS 2006 115,000 Domestic Irrigation

Ecovillage at Currumbin QueenslandAustralia OSI 2007 75,000 Domestic Toilet Flushing, Irriga-

tion, Washwater

Las Vegas Regional Animal Campus Nevada LMS 2004-2006 95,000 Animal Waste Washwater

Moore’s Creek Demo Virgina LMS 2007-2009 15,000 Domestic None

Esalen Institute California LMS 2007 25,000 Domestic Irrigation,Groundwater Recharge

Old Trail School Ohio LMS 2008 20,000 Domestic Surface Disposal

Furman University South Carolina LMS 2009 20,000 Domestic Toilet Flushing

YMCA Camp Campbell California LMS 2010 27,000 Domestic Irrigation, Groundwater Recharge

Port of Portland Oregon LMS 2010 20,000 Domestic Toilet Flushing, Cooling Water

Western Wayne County Elementary Pennsylvania LMS 2011 27,000 Domestic Irrigation

San Juan Island Residential Community Washington LMS 2011 27,000 - 150,000 Domestic Irrigation

Dole Foods Demonstration Hawaii TVA 2000 225,000 Domestic Irrigation

A Place on the Beach Residential North Carolina TVA/ Biocon-cepts Inc. 2007 225,000 Domestic Irrigation

Windward Dunes Residential North Carolina TVA/ Biocon-cepts Inc. 2009 70,000 Domestic Irrigation

3

All technologies surveyed are capable of consistently meeting reuse requirements. However, the technologies vary according to footprint, energy use, operational requirements, capital and lifecycle costs. Permitting requirements varied according to geographic location, reuse application, and sometimes system size. All water quality analyses were performed by certified laboratories or by third parties using Standard Methods for the Examination of Water and Wastewater (19th ed.).

Centralized municipal wastewater treatment represents a homogenized wastewater source due to the aggregation of thousands of different users. Decentralized treatment systems however are

subjected to a much larger variation in wastewater concentrations. For example, influent BOD varied between 700 mg/l and 31 mg/l. Influent TKN varied between 198 mg/l and 23 mg/l. This represents a range 3X to 1/3X average municipal concentrations a ninefold concentration range (Tchobanoglous et al., 4th ed.).

The surveyed decentralized systems consistently met tertiary reuse standards even with widely variable influent concentrations (Figure 1-3).

CASE STUDIES

Table 2: Decentralized systems permitting and performance data

In!uent5 (mg/l) E"uent (mg/l)

Project Biological Treatment Technology BOD TSS

TKN/NH4

+ /TN

BOD TSS TKN NO3 NH4+ TN Turbidity

(NTU)Coliforms

(CFU/100ml) Viruses

Blacktown Workers Sports Club Aquacell MBR 700 370 43 1 <1 10 <1 <1

Vinosa Apartments Prince Henry Little Bay Aquacell MBR 84 76 <2 <1 <1 <1

1 Bligh St Sydney Aquacell MBR 600 600 <5 <1 <1 6 log reduction

Solaire Apartments2 GE MBR 230 45 <101 <101 <31 <5` <1001

Oregon Health Sciences Uni-versity2 GE MBR 263.6 330.6 0.21 0.07 0.17 0.07 0.04

Dockside Green Community2 GE MBR N/A3 N/A3 N/A3 5.04 2.7 3.2 24 .31 15.2 1.3 1

Vancouver Convention and Exhibit Centre GE MBR N/A3 N/A3 N/A3 4.87 0.43 1.01

Sidwell Friends School HFW + TF + SF 162 95 117 6 12 8.69 19.99 28.68 <2 2.37

Omnilife Stadium TF + HFW + SF 31 48 130 <1.98 <5 <5 3

Willow School HFW + SF 218.5 77.5 140.5 <10 <10 7.43 0.43 5.54

Woodland Park Zoo - Penguin Exhibit HFW 160 100 80 21 15 20.8 0.6 21.4

Ecovillage at Currumbin OSI Advantex 3.4 1.9 14 1 9 log reduction

Guilford County Northern Middle + High Schools Living Machine TFW 120 150 198 1.97 0.2 4 16 5.16 21 103

Las Vegas Regional Animal Campus Living Machine TFW 117 72 1.64 3 1.5

Moore’s Creek Demo Living Machine TFW 169.7 62.4 44.7 7.2 5.1 2.6 3.6 8.9

Esalen Institute Living Machine TFW 183 110 40 1.4 3.4 0.9 5.1

Old Trail School Living Machine TFW 257 132 55 3.9 1.8 1.1

Furman University Living Machine TFW 200 60 58 2.5 1.08 2.2

YMCA Camp Campbell Living Machine TFW 316 153 117 4.5 10 5.64

Port of Portland Living Machine TFW 270 55 163 3.8 2.1 1.5 0.6

Western Wayne County El-ementary Living Machine TFW 177.5 125 <51 <51 <51

San Juan Island Residental Community Living Machine TFW 200 70 75 <51 <51 <51 <101

Dole Foods Demonstration4 Recip TFW 140 23.7 7.5 3

A Place on the Beach Residen-tial4 Recip TFW 250 75 60 1.87 0.74 5.75 3.9 9.65 1.36

Windward Dunes Residential4 Recip TFW 250 75 60 4.2 1.03 7.1 0.74 7.84 12.5 1Meets or exceeds permitting requirements 2Awaiting full test results from regulators 3Monitoring of parameter not required 4Technology currently licensed by LMS 5!""#$%&'(%)#*+,#%+%#-./#010)(20#3,(#4+""(4)(5#3*)(,#6,$23,1#)3%7-./#8#-(29,3%(#.$+,(34)+,# :;<#8#:+,$=+%)3"#;"+>#<()"3%5# ########?;#8#?,$47"$%@#;$")(,# ########A;#8#A3%5#;$")(,## #?;<#8#?$53"#;"+>#<()"3%50

4

Four case studies are presented which explore project history, project goals, treatment, design, and lessons learned.

Case Study - 1 Bligh St Sydney, Australia

1 Bligh St. in Sydney’s Central Business District is the first high-rise commercial office tower to incorporate blackwater recycling technology (See

Figure 4). The project, co-owned by DEXUS and Cbus Property, houses over 2,000 employees and saves over 100,000 liters of Sydney’s drinking water per day or over 30 million liters per year, reducing potable water use by up to 90%. DEXUS, one of Australia’s leading diversified property groups, was recognised for the second year running as one of the Global 100 Most Sustainable Corporations. (Davos World Economic Forum). Treatment and Reuse System

Wastewater is collected from the building sewer and supplemented by ‘sewer mining’ an adjacent municipal sewer (Figure 4). Wastewater is collected in a primary and equalization tank before treatment in an Aquacell membrane bioreactor. This technology combines solids removal, biological treatment, and membrane ultrafiltration in a single package plant located in the building basement. Treated wastewater has elevated levels of salts which are removed via reverse osmosis. Reject brine water is sent to the municipal sewer.

Dual disinfection (UV light and chlorine) is utilized to assure that reclaimed water is safe for building reuse. Reclaimed effluent is stored in a reuse tank before being pumped back into the water reuse system in the building. Supplemental potable water can be added as make-up if the system is offline or does not have sufficient flow. The elliptical shape of the building required significant customization to fit the treatment system into the basement.

In addition to the wastewater reuse system a rainwater catchment system collects rainfall from the roof and utilizes it for interior irrigation of planted areas. By treating and reusing wastewater from the building and municipal sewer as well as rainwater catchment, the 1 Bligh Street project is able save over 30 million liters of potable water per year.

Costs Benefits and Drivers The initial reason for installing the blackwater plant was to assist the building to achieve 6-star rating under Green Building Council of Australia’s 6 Star Green Star Office Design v2 Certified rating. By using water for toilet flushing and cooling towers, the building achieved the maximum water points. This contributes to a higher rental yield for the developer, and the building has created a benchmark in sustainability in Sydney’s downtown. The system produces 100kl/day treated water. 75 kl/day is for cooling tower use, and 25kl/day is for toilet flushing. 25kl/day wastewater is sourced from

Figure 1-3: Influent versus Effluent for wastewater monitoring parameters; Biological Oxygen Demand (BOD), Total Kjeldahl Nitrogen (TKN), and Total Suspended Solids (TSS)

5

the building, and the remainder is from the adjacent sewer. The building is yet to undergo a full year of operation, but current indications are that savings in water and sewer charges are estimated to be $150,000 p.a. Operating costs, excluding power are expected to be approximately $40,000 p.a and power to $16,000 p.a. Water pricing is increasing in Sydney at a rate faster than inflation, so the savings will increase in future. Changing Regulatory Environment in Australia

The 1 Bligh Street project is also unique in that Aquacell was granted the first combined private network and retailer’s license for water recycling. The license has been granted under the Water Industry Competition Act 2006 (WICA) and is part of a New South Wales (NSW) Government strategy for a sustainable water future. The granting of the license is an important part of a sustainable future for NSW. Recycled water schemes like this will ease

pressure on water, energy and land as populations increase. Achieving this license required significant investment of time by Aquacell to demonstrate the technical, financial and organizational capabilities of the company and the long-term financial viability of the project. Case Study – Ecovillage at Currumbin, Queensland, Australia

The Ecovillage at Currumbin is an award-winning planned community located on a 270-acre site on the Gold Coast of Queensland, Australia. Approximately 150 homes, a village center, school, and other community facilities will be built using state-of-the-art sustainable methods, materials, and systems. The village will offer complete autonomy in water, energy, and wastewater management. The project has already won numerous awards, including the International Real Estate Federation’s (FIABCI) 2008 Prix d’Excellence.

Figure 5: Process diagram of the Advantex System installed by Orenco Systems, Inc. at the Ecovillage at Currumbin in Queensland, Australia (see Appendix A for symbol legend)

Primary TankEqualization Tank

Reuse Tank

Toilet

Municipal

Sewer

Ultraviolet

Disinfection

Chlorine

MicroFiltration

Membrane

Anoxic and Recirculation

Tank

Transfer Tank Feed Tank

Irrigation

Wash WaterWet Weather

Storage Tank

Advantex

Textile Reactors!"

Figure 4: Process diagram of the Aquacell system installed at 1 Bligh St, Sydney, Australia (see Appendix A for symbol legend)

!"

Municipal

Sewer

Reverse

Osmosis

#$

Ultraviolet

Disinfection

Chlorine

Cooling

Tower

Sink Toilet

Building

Conveyance

Effluent TankMembrane

BioreactorPrimary Tank

Reject to Sewer

Brine to Sewer

6

The commercial center and 110 of the residential lots at The Ecovillage are connected to a decentralized community wastewater recycling system that collects, treats, and redistributes water back to the homes. The remaining lots are served by individual on-site systems, as part of the overall plan to use the most appropriate technology across the project site.

Treatment and Reuse System The wastewater treatment and reuse system was

commissioned in November 2007, and is designed to treat up to 100,000 liters per day of raw wastewater to Australia’s Class A+ levels (Figure 5). A watertight sewer ensures that there is no infiltration and inflow into—or exfiltration and overflow from—the system. After flow equalization and primary clarification, an AdvanTex® Modular Treatment System is used for biological treatment. Advanced biological treatment, including nitrification, denitrification and filtration is completed with a membrane micro-filtration unit. UV disinfection and chlorine addition is utilized prior to storage in the Reuse Tank to assure water quality throughout. Orenco’s TCOM™ telemetry control panel allows remote monitoring and control of the secondary treatment process. Effluent is reused by residents for toilet flushing, car washing, laundry, and irrigation. A supplemental wet weather storage pond is utilized to store treated water during the rainy season. Long-term Performance The AdvanTex treatment system and associated microfiltration and disinfection components were chosen by the developer over competing technologies

based on a lifecycle analysis of energy and economic considerations. The Orenco integrated system has

met the Queensland regulatory agency's water quality effluent requirements for the past four years.

Case Study – Omnilife Stadium, Guadalajara, Mexico

Omnilife Stadium, design by VFO Arquitectos, is home to the renowned Mexican Football Club Chivas. It is the 4th largest stadium in Mexico with seating capacity of 49,850 and is the first major stadium with a total wastewater treatment and reuse system. The stadium owner wanted to meet higher water quality standards and to demonstrate reuse of the reclaimed wastewater. The Architect incorporated the design of the treatment system into the entry to the stadium.

Treatment and Reuse System During each game up to 600,000 liters of

wastewater can be generated, typically in a 2-4 hour period. Wastewater is stored in a 1200 cubic meter primary treatment / equalization tank and metered out at 113,550 liters per day into an integrated biological treatment system. The treatment system, designed by Natural Systems International, is composed of a series of biological and filtration processes (Figure 6). Serial treatment includes clarification and equalization, followed by, trickling filters (4 pairs), and a horizontal subsurface-flow wetlands. A recirculating sand filter provides final biological treatment. Sand filter effluent is pumped through an 80-micron cartridge filter, 5-micron bag filter, and a UV disinfection system before entering a reuse storage tank. Reuse water is utilized for toilet flushing, subsurface irrigation, and stadium washdown reducing potable water use by up to 80%.

Not unique, but perhaps compounded by regional electrical and logistic infrastructure, the

Figure 6: Process diagram of the NSI, Inc. designed system installed at the Omnilife Stadium in Guadalajara, Mexico(see Appendix A for symbol legend)

!"#

Horizontal Flow

WetlandEqualization TankFIltrationPrimary Tank

!$#

Sink Toilet

Irrigation

Wash Water

Effluent TankUltraviolet

Disinfection

Sand

Filter FiltrationTrickling

Filter

Stadium

Conveyance

7

ability to obtain specialty technology items quickly can be challenging. Items like specialty sensors and controls took longer to receive initially. As poor regional electrical infrastructure shortened the life of certain equipment, the need to have in stock replacement parts was essential to maintain consistent operations.

Case Study – Marine Corps Recruit Depot, San Diego, US

The US Department of Defence (DoD) through the Environmental Strategic Technology Certification Program (ESTCP) evaluates and certifies new environmental technologies that hold promise for DoD facilities. The Living Machine® treatment technology was selected for a full-scale demonstration and evaluation. The Marine Corps Recruit Depot (MCRD) volunteered to be the test site for this technology. MCRD is located between the airport and downtown San Diego, CA, and provides basic training for half of all Marine Corps recruits. The base is a leader in incorporating sustainable technologies and will demonstrate onsite wastewater treatment and reuse, thereby reducing, potable water consumption.

A Water Reuse Master Plan for the base identified irrigation of turf and landscape plants as the most economically compelling reuse option. Sewer mining of existing wastewater laterals was proposed as a source of influent.

Treatment and Reuse System A sewer pump station was installed to intercept

40,000 liters per day of wastewater from the barracks and dining services (Figure 7). This represents less than 5% of potable water by the base, or the use by about 130 marines. An equalization tank was installed to buffer diurnal variations in wastewater flow. Wastewater flows were found to follow distinct diurnal trends which reflect the regimented schedule of rising at 5:00 am and lights out at 9:00 pm. A significant peak in wastewater was noted in the 30 minutes proceeding lights out due to showering. The capacity of the equalization tank was increased to

accommodate this schedule. The Tidal Wetland Living Machine® Treatment System provides solids removal, and advanced biological treatment. A denitrifying recycle within this system removes nitrate and other oxidized nitrogen compounds. After biological treatment dual stage filtration is used to remove residual solids. Ultraviolet disinfection and chlorine addition are provided to assure adequate disinfection and to meet stringent California reuse regulations. Treated effluent is stored in a reuse tank and used for subsurface irrigation. Online turbidity and chlorine residual (ORP) sensors provide continuous feedback on system performance to the web enabled touch panel computer control system.

Web enabled computer control systems are utilized for all Living Machine® projects and significantly reduce the need for onsite oversight of the system during normal operations. For this project however the remote monitoring capabilities of the control system had to be deactivated due to military security protocol. This resulted in some increased time for facility staff to review system functioning on a regular basis in addition to scheduled maintenance.

Site Integration MCRD facility staff selected a location adjacent to an existing monument dedicated to drill instructors on the most prominent quad. Landscape Architect Julie Bargmann and her team at DIRT Studio used the Living Machine treatment system as the central landscape element to highlight the existing monument and to create a courtyard space to accommodate visitors at the monthly graduation ceremonies. All primary tanks, effluent polishing systems and disinfection modules are secure and located below grade. The aesthetic appeal of the treatment system has allowed it to be incorporated within a public area and directly adjacent to the irrigated areas.

CONCLUSIONS AND RECOMMENDATIONS Drawing from the survey, case studies and working experience, the authors have compiled a set of conclusions and recommendations to promote the successful implementation of decentralized treatment and reuse.

Figure 7: Process diagram of the Living Machine System at the Marine Corp Recruit Depot in San Diego, CA(see Appendix A for symbol legend)

Primary Tank

Equalization TankEffluent Tank IrrigationLocal

Sewer

Ultraviolet

Disinfection

ChlorineLiving Machine

FIltration

Backwash to Primary Tank

8

• Balancing Cost/Benefit/Safety - The best place to begin the design of a wastewater reuse project is with an assessment of the water resources and reuse applications. For example, capturing rainwater from roof structures and using it for subsurface irrigation requires little or no treatment. Rainwater is a low risk water source and subsurface irrigation is a low risk application. However, the use of graywater or blackwater requires enhanced levels of treatment depending on the reuse application. Decentralized technologies must be tailored to expected waste stream influent qualities and be selected for the desired reuse application. A key to long-term viability is a system that is flexible and easily adapted to changing influent or desired effluent quality. The goal of decentralized treatment is to develop elegant systems that are energy efficient, cost effective, and relatively easy to operate. When possible, centralized and decentralized systems should be integrated to develop a more resilient, cost effective, and sustainable water system.

• Aesthetics – In most urban, suburban, and even rural locations aesthetics can be an important factor in the acceptance of decentralized treatment and reuse. This applies to both the treatment system as well as the product reuse water. To become widely adopted, treatment technologies need to be either beautiful site amenities or virtually invisible, located below grade and/or in basements or other non-obtrusive locations. No wastewater should be visible or odors detectable during the treatment process.

• Economics – Costs of constructing, maintaining and operating conventional municipal water and wastewater systems have been rising over the past decade. The average increase in potable water rates in the US in 2010 was 9% and many areas of the country are experiencing even higher rate hikes. Municipal sewer rates are also

increasing significantly. Micro-utility models employed in Australia and certain US states could be an important economic driver for wider adoption of decentralized technologies. Simple cost analysis of decentralized treatment and reuse is difficult to calculate due to variability in applications, regulations, building costs, and other project specific factors however general trends can be represented. Figures 8-10 provide life cycle analysis for Living Machine® Treatment systems but the general trends would apply to most decentralized treatment technologies. Operator and monitoring costs are the two largest and most variable costs (Figure 8). Similar reuse applications in different cities or states can be subject to monitoring cost increases up to 10X larger. Monitoring costs and operator costs are largely scale independent. Aggregate cost and savings (from water and sewer reductions) are depicted in Figure 9. Current municipal water and sewer rates for the city of San Francisco were used for this calculation. Estimated operations costs include primary treatment, biological treatment, and polishing (disinfection and final filtration) but not collection or reuse system operations which are highly variable. Figure 10 depicts simple payback but again does not include capital costs for wastewater collection and reuse piping. These additional costs will lengthen payback but are highly variable. In certain cities like San Francisco, installation of ‘purple’ (reuse) piping is required even if reuse sources are not currently available. The wastewater source for this analysis was assumed to be residential and significantly higher capital costs would be required for commercial or office wastewater sources that have significantly higher nutrient concentrations. For decentralized systems the payback interval would begin to increase at a certain point as it became more expensive to integrate disparate collection sources and

9

provide disparate reuse facilities. There is likely to be a ‘sweet spot’ where increasing flow rate decreases per gallon treatment costs before increasing collection and distribution costs outweigh these savings. These factors vary on a project-by-project basis. While these figures are very generalized they demonstrate the importance

of scale to the economic viability of decentralized reuse. The importance of scale is widely recognized but is not explicitly considered by the LEED or the Living Building Challenge ratings systems nor most regulatory agencies.

• Regulatory Environment – The regulatory environment is perhaps the single largest hurdle to adoption of decentralized wastewater treatment and reuse in the US and Canada. In the absence of federal legislation both environmental and public health organizations compete for jurisdiction in many projects. Most regulators are sympathetic to the goals of decentralized reuse but are hampered by outdated or inappropriate regulations developed for centralized municipal reuse. Because of the sensitive nature of decentralized reuse projects, all projects must ensure that public health and the environment are well protected.

A risk management approach involves actively identifying and managing risks, rather than simply reacting to problems as they arise. North America has a lot to learn from Australia in this regard. In 2006, Australia developed an internationally recognized framework for managing risks within a wastewater reuse program; whatever the size, source or non-potable reuse. The Australian Guidelines for Water Recycling (AGWR): Managing Health and Environmental Risks is a great resource for engineers, regulators, and public officials concerned with reuse and public health. AGWR borrows a risk

management approach that’s been used in the food industry for many years, known as HACCP or ‘hazard analysis using critical control points.’ Under this approach, producers first identify any potential hazards to food safety, and then identify particular points (critical control points) in production and preparation systems where action can be

Figure 8-10: Yearly cost, revenue and payback analysis based on blackwater system with reuse averaged over the first ten years of operation

10

taken to reduce or eliminate the risk that the hazards will occur. Establishing a regulatory systems that protects public health and the environment and is appropriate for the scales and applications of decentralized treatment and reuse is critical.

• Operations - One of the most important

components of AGWR’s framework is the requirement for a comprehensive system management plan. Operations of decentralized treatment and reuse systems should be handled by certified wastewater treatment operators or by individuals undergoing appropriate training programs. Operator certifications levels need to be developed that reflect the challenges of decentralized versus centralized treatment systems. At present there are very few licensed operators in urban areas and operations costs are inflated as a result. Market opportunities exist for operations and maintenance firms in these areas.

• Politics - There are strong political impediments to the adoption of decentralized treatment and reuse. There is a network of entrenched interests representing municipal utilities, regulatory agencies, large consulting engineering firms, and technology vendors who continue to benefit from centralized water and wastewater infrastructure projects and oppose decentralized treatment and reuse (Nelson 2008).

• Nutrient Reuse – Nutrients in wastewater can also be viewed as a valuable resource. Wastewater treatment and reuse systems can be designed to convert nutrients like nitrogen and phosphorus to optimum forms for agricultural or landscape reuse. Nutrient reuse is a component of LEED Pilot credits and is an area of active research and development (Fach and Fuchs 2010, Lienert and Larsen 2010).

REFERENCES

1. Anning, H., (2009). Case Study: Bond University Mirvac School of Sustainable Development Building, Gold Coast, Australia. Journal of Green Building, 4(4): p. 39-54.

2. Bradford, A. and C. Denich, (2007). Rainwater Management to mitigate the Effects of Development on the Urban Hydrologic Cycle. Journal of Green Building, 2(1): p. 37-52.

3. Cook, E., (2007). Green Site Design: Strategies for Storm Water Management. Journal of Green Building, 2(4): p. 46-56.

4. Eaton, A., L. Clesceri and A. Greenberg, (Eds.). (1995). Standard Methods for the Examination of Water and Wastewater (19th ed.). Washington, DC: American Public Health Association.

5. Echols, S., (2007). Artful Rainwater Design in the Urban Landscape. Journal of Green Building, 2(4): p. 103-122.

6. Fach, S. and S. Fuchs, (2010). Design and Development of Decentralized Water and Wastewater Technologies: A Combination of Safe Wastewater Disposal and Fertilizer Production. Water Science and Technology 62(7): p. 1580-1586.

7. Gavasci, R., A. Chiavola and M. Spizzirri, (2010). Technical-economical Analysis of Selected Decentralized Technologies for Municipal Wastewater Treatment in the City of Rome. Water Science and Technology, 62(6): p. 1371- 1378.

8. Gikas, P. and G. Tchobanoglous, (2009). The Role of Satellite and Decentralized Strategies in Water Resources Management. Journal of Environmental Management, 90: p. 144-152.

9. Goddard, M., (2006). Urban Greywater Reuse at the D’LUX Development. Desalination 188: p. 135-140.

10. Hatt, B., A. Deletic, and T. Fletcher, (2006). Integrated Treatment and Recycling of Stormwater: A Review of Australian Practice. Journal of Environmental Management 79: p. 102-113.

11. Holman-Dodds, J., (2007). Towards Greener Stormwater Management. Journal of Green Building, 2(1): p. 68-96.

12. Leatherman, P., (2009). Burton School Rain Water Harvesting System – An Educational Tool with Sustainable Benefits. Journal of Green Building, 4(4): p. 19-28.

13. Li, F., J. Behrendt, K. Wichmann and R. Otterpohl. (2008). Resources and Nutrients Oriented Greywater Treatment for Non-potable Reuses. Water Science and Technology 57(12): p. 1901-1907.

14. Lienert, J. and T. Larsen, (2010). High Acceptance of Urine Source Separation in Seven European Countries: A Review. Environmental Science and Technology 44: p. 556-566.

15. Lohan, E. and W. Kirksey, (2011). Decentralized Wastewater Management. In S. Coyle (Ed.), Sustainable and Resilient Communities: A Comprehensive Action Plan for Towns, Cities and Regions (p. 227-238). Hoboken, New Jersey and Canada: John Wiley & Sons, Inc.

16. Lynch, D. and D. Dietsch, (2010). Water Efficiency Measures at Emory University. Journal of Green Building, 5(2): p. 41-54.

11

17. Nelson, V., (2008). Institutional Challenges and Opportunities: Decentralized and Integrated Water Resource Infrastructure. Coalition for Alternative Wastewater Treatment.

18. Tchobanoglous, G., F. Burton and H.D. Stensel (Eds.). (2003). Wastewater Engineering: Treatment and

Reuse (4th ed.). New York, NY: Metcalf and Eddy, Inc and McGraw Hill.

19. 2030 Water Resources Group, (2009). Charting Our Water Future: Economic Frameworks to Inform Decision-making. International Finance Corporation and McKinsey & Company.

APPENDIX A: Process diagram legend

APPENDIX B: Key Terminology for Table 2

Influent – Volume of water flowing into the system

Effluent – Volume of water flowing out of the system

BOD5 – Biological Oxygen Demand is the amount of dissolved oxygen required by the microorganisms to breakdown the organic matter in the water over five days

TSS – Total Suspended Solids is the measure of solids suspended in the water volume

TKN – Total Kjeldahl Nitrogen is the sum of organic nitrogen, ammonia and ammonium in the water

NH4 – Chemical formula for ammonium

TN – Total Nitrogen is the sum of TKN, NO3 and NO2

NO3 – Chemical formula for nitrate

Turbidity – A measurement of the cloudiness of water due to suspended particles

Coliforms – A group of organisms used to indicate the level of fecal contamination

Viruses – Measures the reduction of pathogenic viruses found in wastewater using log-reduction (factors of 10), which can be converted to percent reduction (e.g. 2 log reduction = 99% and 4 log reduction = 99.99%)