Healing Appalachia: Sustainable Living through Appropriate Technology

26. Composting Toilets

Several years ago the folks at ASPI, as part of their U.S. Environmental Protection Agency Small Grants Program, installed a compost toilet here at our television studio/office. It has worked beautifully for the past six years and we have become satisfied users and promoters. We hear that this is the only compost toilet in a television station in Appalachia. The compost toilet is part of living the way we ought, consuming less resources and solving the waste problems in everyone’s own backyard. Thus WOBZ-TV continues to promote friendly technologies such as compost toilets on its shows, which are viewed throughout much of southeastern Kentucky. Joey Kesler, director, WOBZ-TV, London, Kentucky Appalachia is home to one appropriate technology practice that has immense potential in all parts of the world, especially in sparsely populated areas where sewer systems are quite expensive and in areas where leach field percolation is difficult or impossible. Compost toilets process human waste into a nutrient-rich fertilizer for use as a soil amendment. Risks associated with water-borne waste disposal, including contamination of ground and surface waters and the spread of disease-causing bacteria, are virtually eliminated by the aerobic decomposition of waste material in the closed-container composting toilet, where temperatures , oxygen, moisture, and carbon-nitrogen ratios are properly controlled. CHAPTER 26 Composting Toilets The composting toilet was developed in Sweden in the 1930s. The extremely rocky ground in the Swedish countryside made installation of centralized sewer treatment systems or septic tanks very difficult. Thus there was a need for a safe way to collect human waste on-site and process it in a way that mimicked the process of natural decomposition. Disposal of human waste was not a problem for huntergatherers . With dispersed populations, wastes deposited among leaves in a forest quickly disappeared through aerobic biological action—nature’s way to recycle nutrients. As populations increased, wastes needed to be collected to avoid water contamination and the spread of disease, so latrines were developed, with their attendant unpleasant odors and accompanying varmints. In latrines, waste underwent a slow anaerobic process with some methane generation. Generally the latrine pit was filled in with soil after use and the deposited material was unavailable as a fertilizer. As populations increased further, more sanitary-minded inhabitants tried to flush waste out of the urban areas by the use of water, sending unprocessed wastes to cesspools in less-inhabited or rural areas. Thomas Crapper outfitted London with such a sewer system over two centuries ago, and similar systems were used to some degree as far back as the height of the Roman Empire. However popular these systems were, they were not totally ecologically sound in concept nor much appreciated by rural families forced to endure the stench of the waste. Treatment systems replaced unhealthy and unsafe cesspools, but at enormous economic and environmental cost to communities worldwide. The contaminated wastewater mixture has to be cleaned up for reuse, and this is quite complex. Less-expensive individual septic tanks are not perfect, because either groundwater becomes contaminated or, in areas where the soils have high clay content, little percolation occurs and additional sites for septic systems must be identified. With increasing water shortages and declining water quality, the compost toilet promises to contribute to the solution of waste problems and the elimination of water pollution. The composting toilet is truly nature’s way. 320 ❖ Healing Appalachia HOW THE COMPOSTING TOILET WORKS Composting wastes are not removed to another place by an aqueous medium as is liquid sewage. Rather, they remain in place, composting for a period of time in a container or vault that has access to a current of air. There the waste is combined with carbonaceous material (wood chips, sawdust, peat moss, chopped leaves, or other loose organic materials). The decomposition process generates carbon dioxide and water vapor, which are vented by natural ventilation or by a fan, which can be solar operated. The carbon-nitrogen balance is maintained, and friendly bacteria do the rest, provided the temperature is above freezing . Since water makes up about 75 percent of the half pound of feces and about 94 percent of the two pounds of urine excreted by an average person per day, residual solid matter is quite low. What comes as a surprise is that the final humus volume (3 to 10 gallons per person per year...