Toilet Options - Ecological Toilets
What is it? Ecological sanitation (EcoSan) is based on three fundamental principles: preventing pollution rather than attempting to control pollution; rendering the urine and feces safe for reuse; and using the safe products for agricultural purposes. This approach can be characterized as ‘sanitize-and-recycle’ (Winblad et.al. 2004), aiming at closing the nutrients loop. Ecological toilets use a minimum amount of water or no water at all. The urine diverting toilets are designed to keep feces and urine (and also possibly water used for anal cleansing) separate, to permit their separate disposal. Most of the nitrogen contained in excreta is in the urine that transmits few of the diseases associated with human waste. (Schistosomiasis and typhoid are notable exceptions in certain areas). Once urine and feces are kept separate, urine can be used as a fertilizer without treatment, with minimal precautions needed to protect health. Fecal matter will also remain dry and therefore easier and more convenient to manage. Increases in storage time, temperature, dryness, pH, ultraviolet radiation, and competing natural soil organisms are amongst the environmental factors used to enhance the treatment and composting pf the fecal matter.
When to use it? Consider its use when (a) there is interest in using digested fecal material, urine or both to fertilize land; (b) people understand and accept the technology; (c) significant training and monitoring is available for the proper use of this system; (d) demand for the urine and compost is demonstrable and/or (e) a high groundwater table or very rocky soil complicate excavation below the surface.
Advantages: Ecological toilets have the potential to produce valuable resources from excreta, while conserving and protecting water.
Disadvantages: Ecological toilets must be operated as designed and this places greater responsibilities on users than conventional sanitation options. They should only be considered where systems to inform users and monitor the subsequent use of the latrines can be put into place. People are less likely to adopt the approach when they already have a latrine, pour flush toilet or WC. Ecological toilets are often significantly more expensive than mere pit latrines.
Technical requirements: Rather than ‘flush away’ or ‘drop and store’ wastes, the EcoSan approach stresses the reuse of wastes as resources. Some commentators advocate the addition of straw and vegetable waste to fecal wastes to optimize the carbon to nitrogen ratio in the waste and thus speed up the decomposition process. Many working in sanitation, however, are skeptical that such additional user requirements will be observed in practice. Most ecological latrines in developing countries have two chambers that are used alternately as in double pit VIPs. Many ecological toilets are or can be built entirely above ground level. This makes the design suitable for places with a high groundwater table or hard sub-surface rock. Some designs include a panel, designed to catch and transmit solar radiation and hence heat up the contents of the vault or chamber; such heating can reduce their water content and accelerate the composting and stabilization process.
For more on ecological sanitation, see Selected Publications.