Compost toilets
Practical Action
Water contaminated with human faeces puts people at a high risk of cholera, dysentery,
diarrhoea, jaundice, typhoid, polio and intestinal worms. A dry composting toilet protects
water and soil and therefore helps protect the people in the community. Coupled with an
effective hygiene awareness programme this can result in significant reductions in the
occurrence of diseases.
Compost toilets are often built with
two chambers for simplicity of
construction and operation. The two
chambers are used alternately;
decomposition continuing in the full
one until it is emptied just prior to the
other one becoming full. Each
chamber has its own opening for
removal of mature, non-odorous
compost. Some types of compost
toilet batch the waste in movable
receptacles on trolleys or turntables
whilst others generate the compost
slowly and continuously as the
material progresses through the
device. Some require electricity for
small heating elements (in cold
climates) or fans (to ensure a positive
airflow through the system). Some
Figure 2: With urine separation one option is to
collect the urine so that it can be used as a liquid
fertiliser later on. Photo: Practical Action, South Asia.
compost toilets combine the urine and
faeces whilst others separate them. The compost formed by the combination of urine and
faeces is better as the urine contains valuable nutrients but these toilets are more likely to
smell if used carelessly and they require much greater quantities of carbonaceous residues like
sawdust and straw. However, urine can be used on its own as a liquid fertiliser so that the
nutrients are not lost. It is collected and stored for a time before being used on agricultural
land. It is relatively safe to handle and store. More complex types of compost toilet design
require dry access under the toilet via a basement or cellar room.
Appropriate use
The compost toilet described here is a highly effective solution to sanitation in high water
table and waterlogged areas. However, it can be used as a reliable and low-cost water
conserving technology in many other areas as well. It can be built beside or as part of a house
in rural, urban or peri-urban areas and can even be established inside a house or apartment.
It has the potential to make a significant contribution to domestic water conservation in towns
and cities as well as rural areas. Also, since there is no need to connect it to sewerage
systems, there is no extra burden on often already overloaded services.
The compost toilet is suitable for use by a family, or it can be built in clusters for institutions,
schools, hostels and so on. However, it is recommended that the use of compost toilets is
managed within the community and that very good education and awareness raising is done
before building begins. Open access community compost toilets are not recommended other
than in well-educated and highly motivated communities.
Location
Any toilet would usually be located on the down-wind side of a dwelling and the same applies
for compost toilets. However, when built and designed well with good education, the compost
toilet does not give any bad odours and can be placed almost anywhere. It should be
remembered that vent pipes only function effectively when there is a passage of air over the
top of them so site selection should take account of this. Access for compost removal should
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