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Helping the University of Idaho Become a National Leader in Environmental Responsibility |
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Helping the University of Idaho Become a National Leader in Environmental Responsibility |
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Eco Dorm Water Analysis By Coreen Crouch - Environmental Science department, Waste Water Treatment Specialist - In the fall and spring of 1999, Coreen Crouch conducted as water use analysis, and researched alternative onsite waste water treatment measures. Her findings and recommendations guide the design of the Eco Dorm water resources system. Abstract The College of Natural Resources (CNR) House is a student cooperative at the University of Idaho. The students that live in the CNR House would like to transform the facility into a sustainable building. The "green" structure would not use outside power and release little to no wastewater. This report presents the findings of a feasibility study of processing wastewater on site. The questions are: are composting toilets suitable for the CNR House and, is a constructed wetland suitable for the CNR House? The methods used were, researching each alternative, analyzing the current building, and collaborating design strategies with student architect Charles Schiers. Some additional information was found such as the current water use, projected water savings, and annual rainfall catchment. Treating wastewater on site is feasible. A constructed wetland is the best alternative for treatment. The recommended wetland design is an Earthship Contained Sewage Treatment System. With this system, indoor planters and a green house will treat all greywater. Most of the blackwater will be treated by an outdoor solar septic tank and planter cells. The treated greywater will be used to flush toilets and water plants. The blackwater will be used as nutrients for outdoor landscaping. By eliminating the need for toilet and urinal water, a 32% water savings is expected.
Introduction There is an opportunity to use new technology and techniques for the defense of the environment. The CNR House is a new student cooperative at the University of Idaho. All students living in the building, formerly known as Targhee Hall, are students of the College of Natural Resources (CNR). These students would like to transform the facility into a "green" building with the support of the CNR, Architecture Department, Environmental Science Program, and the University. The proposed "green" CNR House would be fully sustainable. It would not need any outside power and also release little to no waste. This project could influence not only the future of UI but also campuses worldwide. A university setting is an excellent place to research and set an example of responsible and wise use of the earth’s natural resources. "If we are to achieve a sustainable future, institutions of higher education must provide the awareness, knowledge, skills, and values that equip individuals to pursue life goals in a manner that sustains life and well-being for all current and future generations" (Cortese, 2000). It is simply irresponsible to waste energy and resources. Charles Schiers, architecture graduate student, is the student architect for this project. Environmental Science senior, Paul Chivvis, has researched renewable energy alternatives. Coreen Crouch studied the feasibility of processing wastes on-site. The argument is that the current system wastes water, energy, and squanders potential nutrients. A very small percent of water is actually used for drinking or cooking (approximately 5% of residential consumption). Most of the water we use transports waste. By studying two alternatives for the flow of the waste stream on-site, the best system was determined. The decision was made between composting toilets and a constructed wetland. Problem/Need Statement The purpose is to study the feasibility of treating waste on-site. The goal is to treat 100% of the sewage on the CNR House grounds. Objectives The objectives of this study are: to determine if composting toilets would be suitable for the CNR House. to determine if a man-made wetland would be suitable for this site. to determine if a combination of the two alternatives would be best for this site. Methods Step 1—Research. The alternatives were researched in the library and on the web. Step 2—Water and Waste Program Analysis. The number of plumbing fixtures in the building was determined by walking through the dorm and counting them. They were also located by looking at CAD layout drawings. The minimum number and types of plumbing fixtures needed for the building was also established. This was done by referring to Mechanical and Electrical Equipment for Building (MEEB) (Stein & Reynolds, 2000). Step 3—Survey. The occupants were surveyed to determine water usages and attitudes about the project. This was done by attending the residents’ required meeting, briefly explaining the sustainability project, and handing out the paper surveys. The surveys were collected at that time. Step 4—Climate and Site Analysis. The annual and monthly rainfall patterns were determined through the Idaho Climate Service’s listing. Step 5—Water and Waste Schematic Design & Design Development. This included employing appropriate water and waste design strategies, comparing the conventional water system for the building with a water conserving system, and evaluating whether composting toilets are appropriate for the building or a constructed wetland would be better Results & Discussion Step 1—Research General Composting Toilet Process Information Once considered too unconventional to ever gain mainstream acceptance, composting toilets are emerging in ordinary homes and institutional buildings. They offer a self-contained and lower energy intensive strategy than flush toilets. Working with nature, the systems break down organic material via aerobic bacteria. The process begins when waste material deposited in the toilet builds up into a mound. Wood shavings, or any carbonaceous material, are commonly added with each use to trap air and increase the carbon content in the pile. Organisms, usually aerobic bacteria, start breaking down the substances. The waste is converted into biodegradable substances such as carbon dioxide, water vapor, heat, and compost (Clivus 1, undat.). The bacteria function best when they are in a warm (75-100 oF, or more), moist (45-78% moisture content), dark, aerated environment, working on material which has a proper balance of carbon to nitrogen (30:1) (Rosenbaum, 1998). The end products of composting toilets are solid compost and liquid fertilizer. It is not uncommon for retrieval of finished solid compost to take place 5-10 years after initial start of the system. Only a small amount of fully decomposed soil-like compost remains after the process (Clivus 1, undat.). Compost "tea," high quality liquid fertilizer, is the second end product (Clivus 1, undat.). This compost liquid, derived mainly from urine, undergoes extensive biochemical changes as it passes through the compost filterbed along the bottom of the tank (Clivus 1, undat.). The liquid reaches the clean-out compartment as sterilized fertilizer solution, high in nitrogen compounds as well as other nutrients (Clivus 1, undat.). The liquid can be resprayed to moisten the pile or used as a fertilizer. Both end products are biologically stable and odor-free. To keep the composters maintenance free, it is important to follow a few procedures. This compost should not be removed until it becomes necessary to provide room for fresh in-put material (Clivus 1, undat.). A minimum pile temperature of 65 oF must be maintained (Rosenbaum, 1998). This temperature is important for killing pathogens, making the end product safe for fertilizer application. What kills pathogens is a combination of time and temperature. Pathogens are made harmless if kept at 122 o F (50 o C) for one day (Rosenbaum, 1998). Therefore composting toilets should feature either long retention times and/or high temperatures. Also, the compost must be kept moist, otherwise the composting process halts. There are various devices to keep composters unproblematic. Some toilets included a means of regular mechanical stirring of the compost chamber, aiding aerobic decomposition. A ventilation stack with a small fan is necessary to reduce odors and facilitate evaporation of excess moisture. Also, worms are often added to keep the compost pile porous. Small, self-contained composters, where the entire unit sits in the bathroom, are inadequate to handle full time use in a home or institution. As a result, only "big box" composters are feasible. The three that were researched are the Carousel, Phoenix, and Clivus Multrum. The Composting Toilets The Carousel is a batch composter. It is installed under a waterless toilet. The inner container is divided into four quarter-arc segments and is rotated periodically when the segment currently being used is full. While the next three chambers are being used, the first chamber is slowly continuing to compost. This design ensures no mixing of fresh and composted material. The small size of each segment provides a higher surface-to-volume ratio for the pile, which allows for better aeration (Vera, 1999). The large Carousel, which served 5-8 people year round, is 5 feet high. The Carousel would not be feasible for this project because Vera/Ecotech, the manufacturing company, does not make a Carousel large enough for 60-people’s year round use and there is not space available for multiple units. The Phoenix is the second composting unit. It is a large box structure that sits under a waterless or ultra low flush toilet. It is made from leakproof polyethylene (Phoenix, 1999). It has horizontal shafts equipped with radially arranged tines (Rosenbaum, 1998). The tines both halt the downward progression of the waste and allow for mixing (Rosenbaum, 1998). The Phoenix can be upgraded to a larger unit as needed. However, it also is not large enough for a dormitory’s year round use. The Clivus Multrum is the pioneer in composting toilets (Rosenbaum, 1998). These units were designed 60 years ago (Clivus 1, undat.). Fresh waste is deposited at the upper end of the sloped tank under the waterless or ultra low flush toilet. As composting occurs, the waste material moves "glacially" down the incline to the access hatch, where compost can be removed (Rosenbaum, 1998). The liquid also moves through the pile and is collected as powerful fertilizer or resprayed to moisten the pile. Most importantly, the Clivus is large enough for use in the CNR House. With ample heat, moisture, and space, the Clivus Multrum would be appropriate for use in this project. Toilet Discussion It would be possible to use any of the three composting units described. However, it would not be feasible to use the Carousel or Phoenix. It would be achievable nevertheless by repositioning the two floors of restrooms so they did not stack. Then, it would be necessary to establish more than one Carousel or Phoenix in the CNR House basement. Multiple composting units would be needed and the area required to install multiple composters would be great. It would not be feasible due to cost, effort, and loss of area. The Clivus Multrum would be reasonable. The manu-factures make a Clivus large enough for the CNR House needs. One composter would do the job. There would be no need to buy multiple composters or use extra space. Yet, a problem arises. The two restrooms are located directly above a boiler room in the basement. The design does not include abolishing this solid and stable room. Since it would not be feasible to remove the boiler room, it is not feasible to use a composting toilet. General Constructed Wetland Information Constructed wetlands are a demonstration of how there is no such thing as waste in nature (Stein & Reynolds, 2000). Using plants to filter water is an appealing concept. Wetland treatment is a form of phytoremediation—using living plant systems to solve pollution problems (Wallace, 1998). Its simplicity and reliability makes it an attractive water treatment choice. Water entering wetlands slows down and deposits suspended solids, or contaminants. To survive in these anaerobic conditions, wetland plants have developed mechanisms to transfer oxygen to their root systems (Wallace, 1998). Oxygen diffuses from the plant root hairs into the surrounding environment (Wallace, 1998). Microorganisms that need oxygen can survive in this location. Plants also excrete enzymes through the roots. A combination of oxygen and enzymes create a habitat suitable for a microbial population (Wallace, 1998). The microbes, along with plant transpiration, clean the water. Wetlands operate on ambient solar energy, create valuable wildlife habitat, create oxygen and consume carbon dioxide, and achieve high levels of treatment with little or no maintenance (Wallace, 1998). With time and an increased understanding of nature’s cleaning process, wetlands have come to be viewed in a beneficial light. It may be important to define the different types of water mentioned in this paper. Blackwater is water from flush toilets. Greywater (also spelled graywater) is wastewater from other household sources, such as the shower, washing machine, kitchen sink, etc (Clivus 2, undat.). Three constructed wetland options are discussed. First is a natural, outdoor wetland. The second is a Living Machine. Last is the Earthship Contained Sewage Treatment System. All three choices are conceivable and perhaps feasible. The Wetlands & A Discussion The natural wetland consists of shallow open basins or channels that are lined to prevent seepage. The basins are filled with coarse media such as large gravel or crushed rock. The large voids allow the effluent, which is released below ground level, into the cells to flow freely through rocks and plant root systems. Nutrient rich conditions encourage growth of aerobic and anaerobic microbes, and certain invertebrates. Wetland plants that may grow are reeds, cattails, canna, and iris (Wallace, 1998). These plants not only provide large amounts of surface area for microbial activities, but they also create an aerobic zone underwater by transporting air through plant stems to the roots. A Living Machine consists of a series of "distinct ecologies" each contained within large cylinder tanks (Guterson, 1993). A pipeline connects the tanks and water flows between them. Waste generated by the inhabitants of one tank flows through the pipes and becomes food for the inhabitants of another (Guterson, 1993). This contained marsh and stream achieves a high degree of tertiary treatment. Sunlight is the primary source of energy, which breaks down harmful compounds. The result of a Living Machine treatment is pure potable water. The Earthship Contained Sewage Treatment System is the remaining option. It uses the same wetland approach as the natural wetland to treat wastewater. First of all, measures are taken to reduce water flow from the building. This includes implementing low flow toilets, horizontal-axis washing machines, and aerated water faucets. Plumbing devices separate the grey and blackwater. The greywater is treated inside the building by running it through planter cells with baffles to a final well site. The planters create a "jungle" and the excess water in the well is reused. The blackwater is piped outside to a similar arrangement. The Earthship Contained Sewage Treatment is the most reasonable option. It would be easy to install and students would be able to help build and upkeep the system. Besides being very expensive, a Living Machine is premanufactured and requires specific inputs, such as a variety of tropical plants. Even though it would thoroughly clean wastewater and be beautiful to behold, students would not be able to actively participate in the creation of the system. A natural wetland would also clean the water adequately. However, its location would not have the insulation of the building. Also, the standing water may not be secluded enough from students, for protection to the students and the wetland by accidental or leisure contamination. Last of all, Moscow and the UI already have access to a wetland for tertiary treatment west of town. Students are able to visit and study this natural wetland. After household use, greywater is run to a variety of planter cells in the Earthship System (Solar "Greywater," 1998). The water is first taken to a grease and particle filter. The filter cleans the water so it will not clog the treatment system. The water is then taken through a long pathway of pumice or crushed plastic containers that fill the bottom of the planter cells. Baffles are placed within planters, making individual cells. These baffles are designed to create the longest possible distance through the pumice/plastic. (Solar "Greywater," 1998). The water flows through a final peatmoss filter, then to the end of the planter. At the end is a storage well where water is stored and pumped to water plants and/or flush toilets. The pumice or plastic creates living spaces for bacteria. Above the pumic/plastic is sand and topsoil where plants are grown. The plants will extend their roots through the soil and down into the pathway of the running water. Plant roots bring oxygen into the water. Transpiration also occurs, where the plant roots suck up a large part of the water and transport it to the leaves. From the leaves the water is then given up to the air. The combination of travel through pumice and oxygenation by plant roots, cleanses the water to the point where it looks and smells clean and can be reused. Blackwater is run outside to an elevated solar septic tank. It is placed near the surface of the ground and against the home for borrowed heat (Solar "Black," 1998). The solar heating face incubates the contents and thus enhances the anaerobic process. This tank has a standard outlet line going to a conventional drainfield, which could be used for overflow (Solar "Black," 1998). The outlet is valved so it can easily be closed and, with another valve, the system can be opened to the preferred planter cells (Solar "Black," 1998). The water is then run to shallow cells, similar to the greywater system. They too are placed near the building for borrowed heat, which will extend their productive growing season. The lined cells are created along the perimeter of the building. The water runs from the solar septic tank to the cells where plant roots facilitate oxygenation, filtration, and transpiration. These outdoor plant cells are used as exterior landscaping. These systems do not harm the environment with a final dose of chlorine and only produce one-fourth of the amount of sludge as do conventional systems. They use less energy than energy-intensive pumps and large scale aerators. They are pleasant to look at and smell like a greenhouse. Flushing toilets with greywater is also an important concept. There is no reason to use clean, fresh, drinkable water to flush waste. Step 2—Water and Waste Program Analysis The goal of the water and waste program analysis was to estimate the amount of water the building uses, and how it does so currently, and how it will after remodeling. In doing so, the minimum number of required fixtures was determined (Table 2), as well as the current number and types of fixtures (Table 4), and the number and types projected (Table 3, 5). By determining these numbers, it was possible to evaluate where the water is being used and where it could be conserved. First of all, daily water meter readings were taken for two weeks. From these readings it was possible to determine the amount of water used per occupant (Table 1). It was figured each occupant uses 91.2 gallons per day. From MEEB, it was determined how many water fixtures a dormitory is required to have (Table 2) (Stein & Reynolds, 2000). The current number of fixtures was counting by identifying them individually and looking at the building’s CAD design (Table 4). By looking at the architect’s design and noting the current fixtures, the projected plumbing fixtures were planned (Table 3, 5). The projected number is more than the required number of fixtures purely for occupant convenience and enjoyment. The number of fixtures for the remodel has been reduced from 58 to 55. Many projected fixtures are also low-flow and water conserving, such as the Neptune clothes washer and the "Incredible Head" shower head. ______________________________________________________________________________________ Table 1. Daily readings of the CNR House water meter were taken at 8:35 am (except on 3/28/00). The average water use is 31 gallons x 100 per day. To determine daily occupant water use, divide the total daily water use by the number of occupants. The current total occupancy is 34 students. 3100 gal/day divided by 34 students = 91.2 gal/day/ occupant.
________________________________________________________________________________________________ Table 2. Minimum Number of Plumbing Facilities Dormitory Urinals/Water Closet 1 per 10 Lavatories 1 per 10 Shower/Bathtubs 1 per 8 Service Sink 1 Listed in MEEB, 2000, Table 9.3. Source: International Plumbing Code, 1997.
______________________________________________________________________________________ Table 3. Number of Plumbing Facilities in Projected CNR House (60 students) Dormitory Urinals/Water Closet 1 per 5 Lavatories 1 per 3.75 Shower/Bathtubs 1 per 5 Service Sink 2
______________________________________________________________________________________ Table 4. The current number and types of water appliances and fixtures in the CNR House. Information determined by a walk-through of the CNR House.
gpm = gallons per minute gpf = gallons per flush gpl = gallons per load ---- = no water flow determined 1 = estimate 2 = Maytag Commercial Washer Model A2308
______________________________________________________________________________________ Table 5. The projected number and types of water appliances and fixtures in the CNR House. Information determined by researching low-flow fixtures and appliances.
gpm = gallons per minute gpf = gallons per flush gpl = gallons per load ~~~~ = no water flow change 1 = San Raphael Power Lite Toilet (K-3398) one-piece, Kohler 2 = The No-Flush Waterless Urinal, The Waterless Co. 3 = "Incredible Head" w/ "soap-up" on/off control 4 = Neptune front loading washer, Maytag Step 3—Survey. A simple survey was designed and distributed to the CNR House residents. The purpose of the survey was to determine the residents’ attitudes about the project and water usages. As Figure 1. represents, there were very few negative results. A future dilemma, however, may be the lack of interest of the residents. There was a large percentage of residents who did not answer the questions or had no reactions to the questions asked. ________________________________________________________________________________________________ Figure 1. CNR House Survey Results. Survey given on 02/28/2000 to 24 residents after a brief discussion about sustainable building and water conserving alternatives.
Question 1: Would you support a "green" renovation of the CNR House? Question 2: What is your reaction to composting toilets? Question 3: What is your reaction to low-flow toilets? Question 4: What is your reaction to no-flush urinals?
Step 4—Climate and Site Analysis. The purpose of the climate and site analysis was to determine the availability of water on-site and gauge the possibilities of collecting water and treating wastes on-site. As Table 6 shows, the average yearly precipitation is 25.49 cm. The average monthly precipitation is 2.12 cm. Table 6. Monthly summary for the Moscow Weather Station for the previous 12 months. Temperatures given in oC and precipitation given in centimeters. Average Yearly precipitation = 25.49
Source: Idaho State Climate Services Web Page, last updated 04/14/2000 Step 5—Water and Waste Schematic Design & Design Development. The goal of the schematic design was to take all the gained information and employ appropriate water and waste design strategies. First of all, listed in MEEB a boarding school pupil uses 75-100 gallons per day (2000). This is similar to the estimate of 91.2 gal/day (Table 1). To conserve, low-flush toilets would be used along with no-flush urinals. Greywater from the Earthship Contained Sewage Treatment System would be used to flush the toilets. From Table 7 and 8, toilet and urinal water use can be analyzed. At maximum capacity, the CNR House can save 366,825 gallons of water from toilets and urinals a year. An additional 225,245 and 52,560 gallons per year can be saved with the use of low flow washing machines and shower heads, respectively (Table 9, 10 and Figure 3). Figure 3. shows the process of estimating the projected annual water use, 1,352,650 gallons per year. Compared to the current use, the projected water use would save 32% (Figure 3, 6). From the two weeks of water meter readings (Table 1), the estimaterd annual water use for the CNR House with 60 occupants is 1,997,280 gal/yr. A second estimate of annual water use for the CNR House is taken from MEEB’s assessment of domestic water use (Figure 4) (2000). MEEB identifies 45% of water use for toilets, 30% towards bathing, 20% for laundry and dishes, and 5% for drinking and cooking (2000). By taking the current shower use 578,160 gal/yr (Table 10), and figuring 30% of the CNR House’s water use for bathing, a new annual water use estimate was determined, 1,927,200 gal.yr (Figure 5). The second estimate is similar to our original estimate of 1,997,280 gal/yr. A second estimate of projected annual water use for the CNR House was also taken from MEEB’s assessment of domestic water use (Figure 4) (2000). After eliminating toilet water use, due to greywater recycling, the remaining percentages were redefined (Figure 6). The uses were determined again by figuring shower use, but with a new low-flow head, 2.0 gpm (Table 10). By determining the shower gallons used, 525,600 a year, the new water use estimate could be calculated. The annual projected water use is 973,333. This is not very similar to our original estimate of 1,352,650. This new estimate may not be similar to the previous one because the percentages of water use in Figure 6. may not have been defined correctly because of the use of low flow fixtures or the lack of a flush toilet. Another reason could be wrong input values. Lastly, from the climate analysis, it is possible to determine the average annual rainfall catchment in gallons (Figure 2). An annual 17,202 gallon catchment is possible. By using a catchment system, less city water is needed and natural rainwater can be used. However, gaining only 17,202 gallons out of a needed 1,352,650 projected annual water use, may not be worthwhile ________________________________________________________________________________________________ Figure 2. Average Annual Rainfall Catchment G = [(P)(A)/2.15] (Brown et al., 1992) G = rainfall collected (gallons) P = total precipitation (inches) = annual precipitation x 2/3 A = roof catchment area (ft2) P = 25.49cm x 1 in/2.54 cm = 10 in. x 2/3 = 6.7 in. A = 46 ft. x 120 ft. = 5520 ft2 G = (6.7 in. x 5520 ft2)/2.15 = 17,202 gallons ______________________________________________________________________________________ Table 7. Toilet Use. At maximum capacity (60 occup.) and current capacity (34 occup.) using a standard 3.5 gpf toilet, low-flow 1.6 gpf toilet, and a toilet with greywater input (consider 0 gpf).
Table 8. Urinal Use. Consider males only. At maximum capacity (60 occup.) and current capacity (34 occup.) using a standard 3 gpf toilet, low-flow 1 gpf toilet, and "No-Flush" waterless urinal (consider 0 gpf).
Table 9. Washer Use. At maximum capacity (60 occup.) and current capacity (34 occup.) using a Maytag Commercial Washer (44 gpl) and a Maytag Neptune Washer (20 gpl).
Table 10. Shower head use. At maximum capacity (60 occup.) and current capacity (34 occup.) using a standard shower head (2.2 gpm) and an "Incredible Head" shower head (2.0 gpm).
Figure 4. Domestic water use percentages according to MEEB, 2000 (source: Milne, 1976). All values are in gallons/yr.
Figure 5. A second estimate of the CNR House annual water use using the percentages from figure 4 (60 occup.). All values are in gallons/yr. The values are determined by using the shower use (578,160 gal/yr) from Table 10. A calculation of 100% can be derived from the shower value equal to 30%. Second estimate of CNR House annual water use = 1,927,200 gal/yr.
Figure 6. A second estimate of the CNR House projected annual water use using the percentages from figure 4 (60 occup.). All values are in gallons/yr. The values are determined by using the shower use (578,160 gal/yr) from Table 10. A calculation of 100% can be derived from the shower value equal to 54%. Second estimate of projected CNR House annual water use = 973,333 gal/yr.
Conclusion There are several different on-site wastewater treatment strategies. Two alternatives are suggested: composting toilets and a constructed wetland. The Clivus Multrum Composting Toilet would be an appropriate composting toilet for year round use of a 60 person dormitory. Since no composting toilet is reasonable, due to an existing boiler room positioned under the restrooms, the wetland alternative is chosen. Three wetland options are discussed: a subsurface natural wetland, a Living Machine, and an Earthship Contained Sewage Treatment System. The Earthship Treatment System is recommended. This system would be easy to install, students would be able to build and upkeep the system, and it would be an excellent educational model. With low-flow water devices, an Earthship Treatment System would be a proper way to save water, energy, money, and mitigate the threat of polluting waterways. A university is an excellent location to set an example of responsible use of the earth’s natural resources. If we are ever to achieve a sustainable future, universities must provide the knowledge and skills that sustains life and well-being for all current and future generations. UI could be one of those universities. Refereces Brown, G.Z., Haglund, Bruce, Loveland, Joel, Reynolds, John S., & Abbelohde, M. Susan. (1992). Inside Out: Design Procedures for Passive Environmental Technologies. New York: John Wiley Clivus Multrum (undated) 1. Clivus Multrum Residential Owners Manual [Online]. Available: http://www.compostingtoilets.com/PFMaint.html (2000, Feb. 16). Clivus Multrum (undated) 2. Greywater: Facts About Greywater—What It Is, How to Treat It, When and Where to Use It [Online]. Available: http://www.compostingtoilets.com/greywater.html (2000, Feb. 16). Cortese, Anthony D. (2000) The Vision, Education for Sustainability: The University as a Model of Sustainability [Online]. Available: http://www.secondnature.org/vision/vision.nsf (2000, April 18). Environmental Building News (1998, Feb.) Big Savings from Waterless Urinal [Online]. Available: http://www.ebuild.com/Archives/Product_Reviews/Waterless_urinal.html (2000, Jan. 13). Guterson, Mary. (1993, Spring). Living Machines [2pp]. In Context #35. Available: http://www/context.org/ICLIB/IC35/Guterson.htm (2000, Jan. 19). Idaho State Climate Services (2000, April 14). Monthly summary for the Moscow Weater Station for the previous 12 months [Online]. Available: http://snow.ag.uidaho.edu/data/sum/moscow.htm (2000, April 19). Jade Mountain (undated) Access to Water Savers from Jade Mountain [Online]. Available: http:www.jademountain.com/watsave.html (2000, March 24). Milne, M. 1976. Residential Water Conservation, U.S. Office of Water Research and Technology, Department of Commerce, NTIS. Orr, David. 1999. Architecture of Science. Conservation Biology. 13 :228-231. Phoenix Composting Toilets (1999). Design Features of the Phoenix Composting Toilet [Online]. Available: http://composting toilet.com/Features/Design/design.htm (2000, Feb. 16). Rosenbaum, Marc. (1998, June). Converting "Waste" into Nutrients: Treating Household Organic Waste [13pp]. Environmental Building News [Online]. Available: http://www.ebuild.com/Resources/Rosenbaum/waste.html (2000, Jan. 13). Solar Survival Architecture. (1998). Greywater: Containment, Treatment, and Distribution Systems, Earthship Chronicles. Taos, N.M. Solar Survival Architecture. (1998). Black Water: Earthship Chronicles. Taos, N.M. Stein, Benjamin, & Reynolds, John S. (2000). Mechanical and Electrical Equipment for Buildings ed. 9. New York: John Wiley. Vera/EcoTech (1999). The Carousel 4-in-1 Batch Composting Toilet [Online]. Available: http://www.ecological-engineering.com/ecotech.html (2000, April 17). Wallace, Scott D. 1998. Putting Wetlands to Work. Civil Engineering. 68 (7):57 |
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