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Planning implications of composting toilets

University of British Columbia

The composting toilet is one response to the problems that are increasingly being associated with modern systems of sewage disposal; these problems include high financial cost, accelerated eutrophication of water bodies and the waste of valuable nutrients in human excreta. The last problem makes these systems particularly inappropriate for use in a Conserver Society, a major principle of which is the recycling of physical materials. The purpose of this thesis is therefore to evaluate the suitability of the composting toilet as a sewage system, to determine whether or not it is a feasible alternative to existing sewage systems and to explore the planning implications of installing composting toilets in entire communities as well as in individual dwellings. The theory and operation of a composting toilet is explained in conceptual terms and the two basic types of composting toilets are described and evaluated. Four makes of toilet are described in greater detail in an appendix. The treatment of greywater is recognized as a key component of the total system. The essential differences between greywater and combined wastewater are discussed, particularly as they are related to treatment requirements, and appropriate methods of treatment, existing and proposed, are presented. Following a review of the regulatory status of the toilets, and of the kinds of uses for which they have already been installed, the total system is evaluated as a sewage system in terms of the needs both of today's society and those of a Conserver Society. The analytical portion of the thesis seeks to determine the feasibility of the composting toilet system. The method is a comparative analysis between composting toilets and several sewage systems, including package treatment plants, septic tanks and gravity and vacuum sewers, in the context of two residential areas in the Municipality of Surrey, British Columbia. The analysis is both qualitative, in terms of effects on land use and biophysical systems, and quantitative, in terms of monetary and energy costs. The thesis concludes that the composting toilet is indeed a desirable system for the disposal/treatment of human body 'wastes'. It meets or surpasses the requirements expected of any sewage system, and is suitable for use in a Conserver Society as well. A composting toilet system is a feasible alternative to the proposed sewage systems in each of the comparison areas, and in fact costs less money to install and maintain and requires less damage or disruption to environmental systems. Finally, in addition to financial savings, the use of this system will have important implications for planners and communities, especially the increased flexibility it provides in the location, design, construction and financing of residential subdivisions or single dwellings. The composting toilet system is not only appropriate for use in numerous individual situations, but it should be seriously considered by most low to medium density communities which need to upgrade or install a sewage system.

Text

2010-02-16

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http://hdl.handle.net/2429/20260

Planning

University of British Columbia

Graduate