5 water system study 1 As centralized infrastructural projects reach and pass their centennial, they become artifacts to a past strategy of problem solving, which minimized local adaptation. The threat of resource scarcity has given rise to a diverse range of infrastructural strategies in the last 20 years, as older systems resist effective maintenance on the local level.
Taking an example of a ubiquitous Seattle housing typology, we can examine alternative strategies to centralized sewage. Breaking down an existing system into its constituent parts, we can envision how changes to these parts may effect the whole. This exercise seeks to understand how systems of infrastructure function. The presence of water continues to cull sites of urban development.
feasibility for mutant design Fall 2009 - Ashle Fauvre - Independent Study advisor, Gundula Proksch
3. Infrastructural work recognizes the collective nature of the city and allows for the particiation of multiple authors. Infrastructures give direction to future work in the city not by the establishment of rules or codes (topdown), but by fixing points of service, access, and structure (bottom-up). Infrastructure creates a directed field where different architects and designers can contribute, but it sets technical and instrumental limits to their work. Infrastructure itself works strategically, but it encourages tactical improvisation. Infrastructural work moves away from self referentiality and individual expression toward collective enunciation. - Stan Allen, Infrastructural Urbanism: Seven Propositions, 1999
Infrastructural Urbanism, diagram
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Top-down structure
Centralized Sewage Washington State LEED Living Building Challenge Green Factor UW Urban Agriculture Studio Greenlake Greywater Guerilla
5/1 feasibility study
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When installed in 1904, the centralized sewage system curbed the threat of water borne disease. Landscape architect Frederick Law Olmsted Jr. coordinated with city engineer R.H. Thomson to construct bucolic parks among the marshlands and tidal flats, as well as to provide reliable infrastructure that would allow a balanced relationship between humans and local ecology. For decades, the issues associated with draining marshland and the contamination to the water table from leaky septic tanks gave Greenlake its namesake layer of algal scum. This deterred pleasure swimmers as the lake slowly eutrophied from an overabundance of nutrients. The centralized sewage system drained sewage away from residential neighborhoods, eliminating local contamination. Over the past century, the system has grown complex. Its activities stretch from the edge of Discovery Park to the Cedar River Watershed and out to the agricultural fields east of the Cascades..
The diagram at right shows the major cycles associated with centralized sewage in Seattle.
Regional Water System, overview
evaporative and orthographic rainwater cycle Cedar River Watershed
water distribution to Seattle urban region
wastewater collection to Westpoint Treatment Facility, Discovery Park
separated sediment driven to orchards east of Cascades for use as fertilizer, fruit later driven to Seattle for retail. separated solids driven to landfill
Today, the system becomes overloaded frequently during storm events. Some pipes cannot be maintained because they are made of old-growth redwoods: if emptied and exposed to oxygen, they would fall apart. Sometimes, sewage runs in the streets as an overflow response. Therefore, the centralized sewer system is not the indivisible solution it originally seemed to be. We sacrifice a daily understanding of our relationship with water systems and cycles in exchange for convenience, health safety, and the economies of high volume processing. However, we can now re-evaluate the terms of this exchange.
Drainage and the Sewer: Neighborhood Scale Percent contributed to system by type: Industrial....................1% Commercial..............17% Residential...............25% Stormwater...............53% The stormwater overflow is valve protects the centralized wastewater treatment center from receiving more water than it can process
In Seattle and many cities worldwide, portions of the city flood with a mixture of sewage and stormwater during storm events.
In addition, due to the volume of underground infrastructure, leeks in the system cannot be completely controlled.
1%
17% 23% 53%
The 2008 Smarter Cities Study, a project of the National Resources Defense Council, ranks Seattle #1 among the 67 large cities in the U.S. Seattle ranked #1 in Green Building, Air Quality, and Energy Production and Conservation. For Water Quality, Seattle ranked #5. The Washington State Department of Health is currently reviewing code requirements for greywater, and must make an amendment by December 31, 2010, according to RCW 90.46.015. Rules must be established addressing the outdoor reuse of greywater for subsurface dispersal and irrigation. The Washington State Building Code Council is currently developing rules for greywater re-use internal to buildings. Both agencies will produce a state-wide framework which seeks to balance human health and resource conservation.
At the Greenbuild Conference in 2006, the Living Building Challenge, a concept authored by Cascadia Region Green Building Council CEO Jason F. McLennan, was originally unveiled. The concept advances the framework established by Leadership in Energy and Environmental Design (LEED). Considering the current restrictions proposed by governmental codes, as well as the uncompetitive initial costs of pathmaking tactics, the Living Building Challenge 2.0 manual sets forth 20 principles which builders must address to name their building a “Living Building.�
Options for wastewater treatment Centralized Wastewater Treatment Primary Treatment: Septic Tank Primary Treatment: Aerobic Treatment Units Secondary Treatment: Seepage Pits Disposal Fields Mounds with Leaching Beds Buried Sand Filters Open Sand Filters Recirculating Sand Filters Lagoons: Anaerobic, Aerobic, Aerated, and Facultative Advanced Integrated Wastewater Pond System (AIWPS) Constructed Wetlands Greenhouse Ecosystems Pasveer Oxidations Stream Greywater Recycling and Subsurface Irrigation Greywater Recycling with Drainage to Central Sewer Stormwater Treatment Membrane Bioreactor
viable at the urban scale Centralized Treatment Membrane Bioreactor
Constructed Wetland Greywater Recycling and Subsequent Processing Greenhouse Ecosystem Open Sand Filter
Greywater, Blackwater (from toilet), and stormwater are collected and pumped to West Point Treatment Plant. The largest volume of water in our sewer comes from stormwater, which is clean until it contacts with the greased street surface. Arriving at West Point, the water goes through a few major processes, which form the basic diagram behind most water processing systems. Primary treatment separates solids from liquids using gravity and coarse screens. The greywater is then aerated, and finer particles settle and are removed. Secondary treatment consists of introducing bacteria into the filtered water, which eat most of the pathogens and other toxic organisms. After this day long process, the water is again collected and treated with Chlorine, as a security step. The Chlorine is then neutralized and the water pumped into the ocean in a long outfall pipe.
A. sewage enters treatment: solids filtered B. settlement chambers allow separation of finer particles C. aeration further separates particles D. Secondary treatment using bacteria to clean water occurs in a set of broad concrete cylinders
Combined Sewer: Westpoint Treatment Facility
Primary treatment separates solids from liquids
Secondary treatment introduces naturally occuring yeast bacteria to eat organic contaminants
Chlorination and dechlorination of water is an extra measure, securing decontamination Water is released into Sound
The process illustrated at left is derived from Orange County Municipal Waste Treatment Center, which takes water which has run through the treatment plant and adds an additional process before releasing water to the water table. Membrane bioreactor technology was patented in the 1980s. It is one of the few small footprint treatment options which produces near drinking water quality. Wastewater must go through an a primary separation process. The water is then pushed through cassettes holding millions of tiny polyurethane straws, the diameter of a human hair. The filtered water is then treated with hydrogen peroxide and blasted with UV light. The membrane bioreactor can be integrated with the aeration chamber for a reduced footprint.
Membrane Bioreactor Primary treatment is the same as centralized system.
Secondary treatment is also the same.
In order to make the water potable, a tertiary treatment is introduced. In this case, the water is filtered through a straw-like microscopic mesh. Then the water is exposed to UV light as a precaution. Finally it is ready to drink.
To process wastewater in a constructed wetland is a less technical and intensive procedure than in a membrane bioreactor. Still, the water must pass through a primary purification system if it has been mixed with blackwater. The bacteria process is then accomplished by the wetland. The plant mix will depend on the kind of wastewater (whether from an industrial source or a residential source). The number of stages will depend on the goals for final use. Wetlands can produce potable water, or recharge the water table through infiltration. Special considerations in urban sites include the drainage of the site, the depth of the water table, and the infrastructure which may be above the water table.
Constructed Wetland Primary treatment is the same as centralized system.
To clean the water of bacteria, the water runs through a sequence of terraced beds containing coarse to fine aggregate.
Reedy plants correspond to the coarsest aggregate and dirtiest water. By the end of the process, flowering plants in fine sand may be used. Finally, the water is allowed to infiltrate back into the water table.
This process has the greatest impact on the daily life of the user. Water is diverted and filtered according to its relative contamination. Water from the shower can be filtered for small particles, and divereted into the toilet. Water from the laundry can be used for irrigation after an initial filtration process, as long as biodegradable soaps are used. These initial filters can require cyclical maintenance. Water from the kitchen sink and water from the toilet require heavy processing before they can be re-used, so this water could be diverted directly to a more intensive system.
Greywater Recycling and Subsequent Processing This treatment maximizes efficient use of water in the home. Water uses at home dirty the water to different extents. The plumbing is organized to lead from cleanest initial use to dirtiest. Sink water and toilet water go directly to city sewage. Shower water leads to laundry (after filtering) and then to toilet or infiltration bed (garden or wetland). This system is a hybrid of private and public treatment, lightening the load on central sewage.
Greenhouse ecosystems were developed by eco-pioneers Nancy and John Todd, founders of the Center for the Restoration of Waters at Ocean Arks in 1989. Wastewater goes through primary treatment, and then moves through a series of tanks, each carefully planted with complementary species to create a miniature ecosystem. This eco-system requires the nutrients from wastewater to thrive, and is robust enough to absorb unexpected additives. In the Pacific Northwest, the example below at Islandwood required the tanks to be housed inside a greenhouse, where climate could be controlled. The water filtered by the tanks must pass through a tertiary “polishing� wetland before it is potable.
Greenhouse Ecosystems Primary treatment is the same as centralized system. Industrial waste would require a more intensive system.
To clean the water of bacteria, the water runs through a sequence of terraced beds containing coarse to fine aggregate. Small fish and tilapia may be added to consume waste more quickly. The greenhouse system is a more highly constructed ecosystem, resulting in a more intensive and controlled version of the wetland system. Finally, the water is ready to drink.
A renter in Greenlake shows how combining simple materials, research, and common sense, greywater from the shower can be re-routed to the garden during dry summer months. The same basic principles illustrated in the combined sewer system are utilized. Water is collected, aerated, passed through a biological and a subsequent particulate filter. To meet code requirements and for a final stage of pathogen erradication, the designer plans to install a UV blaster. With this costly improvement, the filtered water would be potable. The system requires weekly maintenence to clean the initial filtered matter from the surface of the tank.
Single Family Sand Filter: Greenlake Greywater Guerilla
Water from the shower is led to an open sand filter.
The sand filter functions as a vertically stacked bed of aggregates. The water moves downward from fine to coarse.
The surface of the water supports biological activity, involving a bacteria-removing process.
Finally, the water is fed by gravity to the garden, where it infiltrates back into the water table.
Greywater Recycling and Subsequent Processing
Open Sand Filter
Greenhouse Ecosystem
Constructed Wetland
Membrane Bioreactor Centralized Treatment
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Comparing Systems: which works for what?
10s of people; a residence and a block
10s-100s of people; a neighborhood
100s-10000s of people; a city
10s-1000s of people; a town
Sources Page 2, 3: Klingle, Matthew. Emerald City: An Environmental History of Seattle. Vail Ballou, Durham, 2007. West Point Treatment Plant pamphlet. “Wastewater Treatment Process”. King County Department of Natural Resources and Parks, Wastewater Treatment Division Page 4: all photos by author, at West Point Treatment Plant tour, storm day, October 2009 West Point Treatment Plant pamphlet, see citation above. Page 5: all photos by author, at house in greenlake, September 2009 Page 6: International Living Building Council“Living Building Challenge 2.0: A Visionary Path to a Restorative Future”. November 2009 Seattle Department of Planning and Government. “Seattle Green Factor” http://www.seattle.gov/dpd/Permits/GreenFactor/Overview/ National Resources Defense Council, Smarter Cities. http://smartercities.nrdc.org/cities/seattle-wa Washington State Legislature. RCW 90.46.015 http://apps.leg.wa.gov/RCW/default.aspx?cite=90.46.015 Page 7: Hirst, Jason; Jonathon Morley, Katie Bang. “Functional Landscapes: Assessing Elements of Seattle Green Factor” Internship Report. Berger Partnership PS, Landscape Architecure, 2008. Page 8: Photo by Lara Swimmer, Seattle Magazine. http://www.seattlemag.com/0p133a995/a-capitol-hill-couple-embraces-life-in-a-glass-house/ Apartment Therapy http://www.apartmenttherapy.com/sf/real-estate/agnes-lofts-seattle-066747 http://yancy9a.blogspot.com/2009/04/philoi-is-greek-for-friends.html Page 9: DPD web site Page 10: section drawing courtesy of Weinstein A+U. water use derived from Cistern Calculator, developed by Rebecca Wilcox, M.Arch candidate, using data from Reynolds and Stein, Mechanical and Electrical Equipment for Buildings, 9th ed, Wiley and Sons, 2000. Fixture data courtesy of Dunn + Hobbes Page 11:Mechanical and Electrical Equipment for Buildings, cited above Page 13: Royte, Elizabeth, “A Tall, Cool Drink of...Sewage?” New York Times Magazine, August 8, 2008. http://www.nytimes.com/2008/08/10/magazine/10wastewater-t.html?sc p=1&sq=water+treatment+drinking+water+california&st=nyt SAF Engineers, New Delhi, Membrane Bioreactor Systems http://www.waterprocessing.in/membrane-bioreactor-systems.html Water Online. “New PURON MBR Module Simplifies Design, Operation And Retrofit Of Large-Scale Plants” 2007. Koch Membrane Systems. http://www.wateronline.com/article.mvc/New-PURON-MBR-Module-Simplifies-Design-Operat-0001 Baxter, Mary. “Hayman Construction enters home stretch at London wastewater plant” Daily Commercial News and Construction Record, May 2008. http://dcnonl.com/article/id27464 Water Recycle Group. “Membrane Bioreactor Filtration”. Australia. http://www.waterrecycle.com.au/mbr.htm Page 14: photos by Abundant Dawn Community http://www.abundantdawn.org/ “Biologist Conducting Water Quality Survey” Laurel, Maryland USGS Patuxent Wildlife Research Center 1994 http://www.pwrc.usgs.gov/resshow/perry/tertiary/tertiary.htm Page 16: photos from flickr, It’s Just Jack, 2004 http://www.flickr.com/photos/jackslife/sets/72157601840709800/ John Todd Ecological Design. http://toddecological.com/eco-machines/
The Feasibility of Greywater Systems in 5 over 1 Mixed-Use Multi-Family Building Typology Principles Statement: Every day, Americans use fresh water for tasks that don’t require them. Meanwhile, natural systems process and slowly clean dirty water, making it fresh again. Having grown up during a 10-year drought in Southern California, the preciousness of water was impressed upon me repeatedly as I grew up. In California, water conservation grows out of dwindling fresh water sources. Although Seattle is susceptible to summer droughts, water does not appear to be in shortage. This study intends to tease out the viability and potential gains of greywater system in Seattle. Significance of Research: 1)Exposing water infrastructure connects inhabitants to natural cycles from which we have become disinherited. 2)Greywater systems in urban situations have yet to be fully explored. Limited case studies exist, although the potential is great for cross-programming multi-family housing to use water more strategically. 3)Minimizing waste through re-use and appropriate programming makes for a more efficient use of resources. Research Statement: In this project I will take a building type common to Seattle and document its water and waste usage. Then I will compare the water and waste usage of greywater systems. By analyzing the data, I hope to be able to propose design iterations or adaptations appropriate to program or context of a similar building type. Seattle Feasability Study: Agnes Lofts, designed by Weinstein A/U, is a six storey , 24 apartment, 40,000 sq.ft. mixed-use apartment building in Capitol Hill. At the AIA Seattle 2008 Honor Awards for Washington Architecture, it received a commendation. Architectural Record web site features Agnes Lofts as a Multifamily Housing Building Type Study. Professor Jeffrey Ochsner, in a tour of Capitol Hill urban design, cited Agnes Lofts as a illustrative of good urban design in a transitioning neighborhood. Sited on the corner property and rising above its neighbors, the building colonizes the block for future development, setting the tone for construction to come. Behind Agnes Lofts currently lies a large empty parking lot, which faces another large empty parking lot. Plans are underway to construct more mixed-use residential units in this space.
photo of L.A. River, courtesy of Carlene Thatcher Martin
Initial literature survey 11 articles from Science Direct: query: greywater lifecycle analysis, greywater Issues raised by literature: -What is the appropriate use of greywater? Irrigation and toilet flushing? -What is the potential for microbrial regrowth after filtration? How clean can you get it with which system? -How do you engineer a wetland for waste water recycling and what can you remove with which system? -Is greywater for agriculture safe for crops and people eating crops? -What happens to crop and soil quality with long term exposure of UNTREATED greywater? -What happens if waste is separated initially and treated according to its qualities? -How much nutrients can be collected from the toilet? -Can we set up a sequence of algorithms to model and accommodate various situations in order to optimize wastewater reuse system? Local resources discovered: PDX: SERA Architects Pearl Family Development Central City Concern Interface Engineering
tension. -EcoSan Ecological sanitation concepts: separate at source and truck to agriculture as fertilizer -Decentralized sanitation systems with source control of pollutants and reduced water consumption (e.g. vacuum sanitation technology, waterless urinals or separation toilets) -biological aerated filters, membranes, bioreactors, Titanium Dioxide (TiO2) dosing, membrane aeration bioreactors and coagulation/flocculation with alum or ferric -Constructed wetlands with horizontal sub-surface flow (HF CWs) (by concept) -constructed wetland **-decentralized sanitation w/source control, separation: focuses on redirecting waste flows to program w/ less hygienic demand (ie toilets, irrigation) –best argument -reverse osmosis membrane filter –most filtration, most expense -bioreactors w/basic chemical process to separate solid/liquid; energy capture -proprietary disinfection and filtration units: Recycled Vertical Flow Bioreactor, Aquatron
REGION: Living Building Challenge Cascadia
Countries writing articles Australia Israel Sweden Tanzania UK US
Risks associated with greywater and blackwater mis-filter Pathogens Viruses Bacteria Protozoa Helminths Trace organics and heavy metals Endocrine disrupting chemicals Pharmaceutically active compounds Nutrients (dissolved organic carbon): can be beneficial in small amounts, if uncontrolled can carry microbial activity and growth Salinity (Toze 2005)
Risks associated with greywater and blackwater mis-filter Pathogens Viruses Bacteria Protozoa Helminths Trace organics and heavy metals Endocrine disrupting chemicals Pharmaceutically active compounds Nutrients (dissolved organic carbon): can be beneficial in small amounts, if uncontrolled can carry microbial activity and growth Salinity (Toze 2005)
Types of systems reviewed: (by keyword) -UV disinfection -Recycled Vertical Flow Bioreactor (RVFB) (expensive) -cation exchange resins or reverse osmosis membranes; high quality recycled water, which will provide a high return for the company providing the treatment water -Aquatron separates by a combination of a whirlpool effect, gravitation and surface
Initial Bibliography Simon Toze CSIRO Land and Water, CSIRO Centre for Groundwater Studies, Centre for Environment and Life Sciences, Private bag No. 5, Wembley, Perth, WA 6913. Australia 2005 Rabindra K. Misra, Amphone Sivongxay Journal of Hydrology journal homepage: www.elsevier.com/locate/jhydrol Reuse of laundry greywater as affected by its interaction with saturated soil Faculty of Engineering and Surveying, Australian Centre for Sustainable Catchments and CRC for Irrigation Futures, University of Southern Queensland, Toowoomba, Queensland 4350, Australia Folke Gu¨nther Ecological Engineering 15 (2000) 139–146 Wastewater treatment by greywater separation: Outline for a biologically based greywater purification plant in Sweden Department of Systems Ecology, Stockholm Uni6ersity, S-106 91 Stockholm, Sweden 1999 Enrico Benetto, Diep Nguyen, Torben Lohmann, Bianca Schmitt, Paul Schosseler Life cycle assessment of ecological sanitation system for small-scale wastewater treatment CRP H. Tudor/CRTE, 66 rue de Luxembourg, BP 144 - L-4002 Esch/Alzette, Luxembourg 2008 C.K. Makropoulos a,*, K. Natsis b, S. Liu a, K. Mittas c, D. Butler a Decision support for sustainable option selection in integrated urban water management a Centre for Water Systems, School of Engineering, Computing and Mathematics, University of Exeter, Exeter, Devon EX4 4QF, UK b Veolia Water Solutions & Technologies, France Enedir Ghisi, Davi da Fonseca Tavares, Vinicius Luis Rocha Rainwater harvesting in petrol stations in Brasília: Potential for potable water savings and investment feasibility analysis journal homepage: www.elsevier.com/locate/resconrec Federal University of Santa Catarina, Department of Civil Engineering, Laboratory of Energy Efficiency in Buildings, Campus Universitario, Trindade, CTC, ECV, Florianópolis - SC, 88040-900, Brazil 2009 Achieving Water Independence In Buildings: Navigating the challenges of water reuse in Oregon
Central City Concern www.cascadiagbc.org/lbc/resources/water/oregon 2009 Allen, Laura; July Oskar Cole; and Cleo Woelfle-Erskine. Dam Nation: Dispatches from the Water Underground.Soft Skull Press. Brooklyn, NY. 2007 For further study: Butler, D., Makropoulos, C., 2006. Sustainable Water Infrastructure: Technological Options and Future Scenarios. UK Environment Agency. 250. Memon, F.A., Butler, D., 2005. Greywater reuse in households. In: Encyclopaedia of Water. John Wiley and Sons. Oasis Design Greywater Policy Center for information on greywater laws and regulations throughout the United States. http://www. oasisdesign.net/greywater/law/index.htm 2009