Transforming Infrastructure: Challenging Mindsets
Installing Composting Toilets on Smith Athletic Fields
Emily Gannon
ENV300
Final Paper
4.25.2011
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Abstract: A move toward sustainability involves identifying areas where we can recycle and reuse our resources, and an area greatly overlooked is our own waste matter. The scale of population and the effluence it creates has made management of human waste a necessary endeavor to pursue. Collecting and treating human waste in wastewater treatment plants as is currently done has served a tremendous importance in creating a healthier, cleaner and more sanitary society. However, current treatment methods make human waste a waste product, while using the valuable resource of potable water both to clean and to dispose of in an environment not conducive to its inherent decomposition capacities. This paper will explore an alternative approach to wastewater treatment at Smith College through the installation of composting toilets at the newly renovated athletic fields. In an effort to reach sustainability goals set forth in the 2009 SCAMP report, composting toilets are a viable way to minimize water use on campus, while simultaneously returning nutrients to the soil, minimizing contamination to our waterways and setting forth a new agenda as a model for a new culture of sustainability. Introduction: Identifying the Problem The SCAMP report released in 2009 identifies minimizing water consumption at Smith College by twenty‐four percent by 2015, and an additional fifteen percent by 2030 as one of its main goals. Methods presented for reaching this goal include education geared to the student body on water use and over use, 2
changing irrigation tactics, and installing more energy efficient products, such as showerheads, faucets and toilets throughout campus housing. Smith College has plans to replace 100 toilets on campus to reduced flow toilets at the rate of twenty per year. To put this water use into perspective, a typical toilet uses about 3 gallons of water per flush, where a reduced flow decreases the water demand by half, using about one and a half gallons of water per flush. For my applied project I decided to see if this was the best possible alternative to minimizing water consumption, and focused in particular on the issue of using potable water to flush our toilets as a point to evaluate: can we do better than this? What I discovered in my research is that not only is another alternative possible, it also addresses many other problems with using current flush, cleanse and release techniques that are impacting the natural environment. Beyond water consumption, the process of treating our wastewater with chlorine impacts the water systems it’s released into. We chlorinate to kill any remaining pathogens that may be present in the wastewater. However, residual chlorine can produce a toxic effect in fish or other biota. (Karr et al, 1985) Beyond chlorine, a plethora of other industrial chemicals move through the treatment plant, such things as hospital waste, pharmaceuticals and industrial chemicals which are not broken down or taken out during the treatment process, therefore end up in the water supply that the water is released into, further compromising the integrity of the ecosystem. A final problem with the current treatment of wastewater is that we are ignoring a valuable resource when we flush our waste. By composting our waste we 3
are converting what was once considered a waste product into a valuable renewable resource. The composting process uses bacterial digestion to turn humanure into rich humus full of nutrients beneficial to the soil. Returning these nutrients to the soil completes an important step in the biological process of the nutrient cycle of returning what was taken out of the soil to produce our food back into the soil to replenish it and start the cycle again. This is a crucial step missing in the way we currently treat our waste. The lack of the process creates a negative effect on our environment as we turn to the use of synthetic fertilizers to return nutrients to the soil. An industrial approach to the treatment of wastewater has been a necessary step to make in order to gain control of pathogens that threatened survival. But we as a collective have gained a deeper understanding and a broader knowledge of how the natural world works, and how we work with and impact the natural world. It is time to reevaluate the current infrastructure on a systemic level as we find ways to exist within nature and utilize the inherent balance it strives to maintain. Recognizing that this balance exists in the composition of humanure‐ that it’s composed to decompose‐ we can readily work with nature to facilitate the break down process, and utilize the results. Methodology Understanding the Need In looking into where composting toilets may fit into Smith’s design I contacted Bob Dombkowski from Facilities Management to see if an opportunity may exist at the newly updated athletic fields, where turf fields were just installed 4
this past fall. His reaction was that he’d been trying for years to get extra restroom facilities, and that the lack of them was a “huge problem”. I was beginning to see an opportunity manifesting. To better understand the need for additional facilities we need to understand how often these fields are used, and what’s in place to accommodate the flow of people. Currently there are three bathrooms on site: two flush toilets in the field house, and one at the tennis court hut. The college rents port‐a‐potties for larger events (usually six per event). The fields consist of a track, a turf field, tennis courts, and a softball diamond, along with a few other open fields for use as whatever event or sports team may need to use them for. These fields get used regularly by the college’s sports teams for both practices and games. The college also hosts other events on these fields, such as a summer camp for junior high school students and track events, such as the 7‐Sisters men and women’s track meet. The need for additional facilities exists on these fields, and this location would allow for the college to explore the option of composting toilets on a small scale before implementing it on a larger scale. The Composting Process The composting process has four basic phases that organic matter passes through before being available for use as humus: 1) the mesophilic phase which begins the process of aerobic breakdown, requiring temperatures between 770‐ 1040 for optimal functioning; 2) the thermophilic phase ‐ the raised temperature during the mesophilic stage provides the optimal heat required for thermophilic 5
bacteria to further break down waste. Further heat is generated at this stage by the thermophilic bacteria which allows the compost pile to reach temperatures between 1050‐ 1700. The heat created during this stage also serves to kill any pathogens present that may be harmful to human health. This stage usually lasts between a few days to a few weeks, which is long enough to eliminate the threat of pathogens survival; 3) the cooling phase; which is a resting stage that mesophilic microorganisms to return and continue whatever remaining breakdown must happen; and 4) the curing phase, where humanure sits for a long period if time (2‐3 years) as it becomes a viable manure. (Jenkins, 2005) Proper conditions must be made for the microorganisms to break down and sanitize the humanure at each phase. Meeting these conditions is not difficult, but proper care must be made to ensure they are met in order to maintain a high level of sanitation. There are four main needs of a compost pile; moisture, oxygen, heat, and a proper carbon/nitrogen (C/N) ratio. (Jenkins, 2005) Moisture is not normally an issue with human excrement, as it’s comprised largely of water. It’s important to keep the moisture levels between 40‐60%. Installing cisterns to the facility would enable the reuse of rainwater if adding water were to the compost were ever necessary. Oxygen is also very important, as it drives the reactions. The bacterial digestion process requires a lot of oxygen. By creating an air flow space under the compost chamber floor and using the batch collection method, the combination of airflow and surface space typically meet the oxygen demand needed for this process. 6
Temperature is important for the purifying of harmful pathogens. Bacteria catalyzing the compost process combine carbon with oxygen to produce carbon dioxide and energy. The microorganisms within humanure use some of this energy for reproduction and growth. The rest is given off as heat. (Jenkins, 2005) As I stated before, the microorganisms in the mesophilic phase give rise to the conditions that will activate the thermophilic bacteria present within our feces. These bacteria thrive at temperatures between 104o‐160O. MA State guidelines stipulate that humanure must reach sustained temperature of 130O for three days to effectively kill pathogenic organisms (Commonwealth of MA, 2005). This phase typically lasts anywhere from a few days to a few weeks, pending on other conditions within. Winter months need not be a concern, as even if temperatures reach freezing, the microorganisms will become active again once temperatures warm to their preferred conditions. The last condition to be met concerns the C/N ration. The ideal levels of C/N ratio are between 25:1 to 30:1, and can be achieved through the use of saw dust or landscaping scraps which provide adequate carbon to balance out the nitrogen rich effluence. State requirements mandate that compost sit for at least two years, but other sources indicate that a three‐year period of composting would be best before safely applying the finished product as a humus layer in landscaping projects on campus. (Jenkins, 2005) 7
State Requirements Composting toilets are becoming more prominent in our culture than ever before, and laws are continuously shifting to address this increased interest. Currently MA State Laws require the use of composting toilets in accordance to guidelines defined under 310CMR15.289. These laws specify that the collection of waste must enter a cesspool where it can sit for a minimum of two years, The law also requires that there is no leaching from this cesspool, and that this cesspool does not extend below groundwater elevation. State law at this time also requires that waste must be removed by a licensed septage hauler to be “properly disposed” of. Further requirements under State law require that: “Residuals from the system shall be disposed by burial on site or in another manner and location approved by the local Approving Authority, covered with a minimum of six inches of clean compacted earth; or by a licensed septage hauler” (310CMR15.289). While this portion of the law doesn’t outright allow for the composted product to be used in landscaping projects, there is always room for the law to change and become more clear regarding this use of the composted product as a deeper understanding of this process emerges. I was able to talk with a community member at Sirius, a completely off the grid intentional community in Shutesbury, MA where the use of humanure in landscaping projects has been happening for years. Through their interpretation of the law, this community digs down the six inches required by the state, spreads the humanure into their landscaping projects, and then covers it with the clean earth they removed to dig the six inch whole. They have been using this 8
method for years without any trouble from the State, is the use does fit within the parameters of State law. Results: Recommendations There are several different composting toilets in use today, using a range of approaches to decompose humanure. This discussion will talk about the approaches that seem most suited for the college’s need. A centralized batch, or multi‐chambered facility, where waste is collected in interchangeable compost reactors, exchanged when full, and allowed to cure under the right conditions for aerobic breakdown of the materials seems optimal for Smith College. This style will accommodate the flow of traffic, as well as allow the humanure to cure undisturbed until it’s ready for use. To best eliminate the problem of odor before it begins, I would suggest the use of ventilation fans sourced by electricity. If properly aerated and properly ventilated, odor is not often a problem. Maintenance would be required to monitor these parameters, but there would be no inherent health risks in taking the job. Currently restroom maintenance is done by Building Maintenance staff, and I would propose that this staff continues to maintain the composting toilets as well. Use of Compost as Soil After a three‐year period viable soil will be provided for landscaping on campus each year. Rate of available product will depend on use of toilets, and will increase as Smith College initiates more composting toilets into building 9
renovations. After the initial three‐year waiting period for the curing of the humus, the college should be able to produce a yearly batch of humus for application. Discussion: A composting technique to treating human waste requires the general public to shift their thinking of humanure as a waste product that’s harmful, dirty and needs to be “disposed of”. This mentality is placing an undue burden on the water systems we are releasing our wastewater into, harming the ecosystems and putting additional chemicals into our water supply. A broader educational initiative is instilled in the general public when institutions such as Smith College innovate in such a bold way. By challenging the infrastructure and the mindsets of the individuals within this culture we begin to move forward with living more in sync with nature and its rhythms. As discussed before, laws must also be flexible to allow for people to take more responsibility for themselves. Once again, proper education must be put forth, but by instilling these educational values on a cultural level, in time, taking a new level of responsibility for ourselves will be second nature. We cannot be afraid of actively seeking new avenues for sustainability out of fear that the public won’t support these measures. We must create the support by treating our waste as something integral to our survival. Without recycling the nutrients that we take out of the soil back into it, we create a niche for an industrialized culture, where synthesized nutrients and chemicals must be added to control parameters that nature could have efficiently done if we simply utilized nature’s machines. 10
I hope that my proposal to install composting toilets on the athletic fields doesn’t end at the athletic fields. I would like the college to consider these installations as just the first step in eventually renovating the entire campus to outfit an alternative to the municipal wastewater treatment that is currently in use. I would also encourage the college to look into other innovative and inspiring alternatives for wastewater treatment that may be built into future construction. Another alternative is the use of technology created by John Todd, called the Living Machine, which is an indoor constructed wetland, where wastewater is cleansed not only by microorganisms and bacteria but also by plants, slugs and fungus. Other models of this approach are sprinkled throughout the country, in environments such as Oberlin College in OH and at a rest area off I‐89 in Sharon, VT. These Living Machines create an indoor greenhouse, and are often set up to recycle the wastewater back through the rest rooms for use a non‐potable water to be used for future flushing of toilets. We are at a point in our culture where waiting for other institutions to make a change is no longer an option. As an influential and well‐respected educational facility, Smith College needs to be a model of positive change for the sustainability of our planet. These changes need to come from all levels, and by bringing such a taboo subject as the treatment of human waste to the forefront of the sustainability discussion we can not only change our ecosystems, but we can also change the negative mentality that has been cultivated in our culture regarding our waste. 11
Bibliography Jenkins, Joseph. The Humanure Handbook: A guide to composting human manure. Chelsea Green Publishing. 2005. White River Junction, VT. Karr, James; Heidinger, Roy C; Helmer, Eileen H. Effects of chlorine and ammonia from wastewater treatment facilities on biotic integrity. Journal (Water Pollution Control Federation) Vol 57, No 9, Sept 1985, p 912‐915. Interviews: Bob Dombkowski, Facilities Management, Smith College, Northampton MA Bruce, Sirius Community, Shutesbury, MA 12