Septic System

From Antivist

'DIY' compost toilet systems

Far more simple and basic DIY systems can also be constructed that require very little cost or maintenance, provided that attention is paid to a number of important factors. The toilet must control odors. This is achieved by ensuring adequate ventilation (sometimes simply by leaving a small gap between the top of the wall and the roof, more sophisticated systems may incorporate some kind of low voltage extractor fan). Odors can also be controlled by either ensuring that urine and faeces are kept separate or by adding sufficient high carbon content 'soak' material (see below) to absorb excess liquid. The design of the composting toilet should allow the material to remain aerated to prevent the compost from becoming anaerobic, which can result in unpleasant odors. It must also either heat the faeces to the point that pathogens are destroyed (a thermophilic process), or else allow sufficient time (up to a year) for such pathogens to break down and disappear naturally (a mesophilic process). The upside however is that they do not use any significant amount of water and they may produce fertilizer safe for small scale agricultural use.

Another variant is the Tree bog - a type of compost toilet which never needs emptying. Nutrient-hungry trees such as fast growing willows are planted around the Tree bog, which take up the nutrients and convert them to biomass which may then be harvested.