Ecological Sanitation: A Concept
Practical Action
Composting Toilets
Composting toilets can treat human waste as either separated or mixed faeces and urine. The
waste is mixed with organic waste from the garden and/or household to encourage the die off
of pathogens. They can also operate by simply adding a handful of soil and ash after each
use. The processes involved in killing off pathogens include moisture reduction (in some
cases), temperature increase, storage and predation from competing bacteria (from household
waste or soil). In developing countries soil composting toilets such as the Aborloo and Fossa
Alterna can provide simple starting points for ecosan facilities.
The Aborloo (figure 4) is one of the simplest types of ecosan facility working on a composting
principle. It consists of a shallow pit and a small amount of soil and ash is added after each
use. When the pit is two thirds full the contents are covered with soil and a young tree
planted upon the site. The latrine superstructure is then relocated to a new pit where the
process is repeated. It is the safest way of recycling the nutrients available within human
waste because humans do not have to handle the waste.
Figure 4: Aborloo toilet [Illustrator: Hans Mårtensson; Source: Winblad and Simpson-Hébert, 2004]
The Fossa Alterna (figure 5) is another form of soil composting toilet. It utilises a similar
principle to the Aborloo, however it is more suited to areas with limited space as it only has
two sites. The superstructure of the latrine is relocated from one pit when the other pit is full.
After a certain period of time, the contents of the original pit can be removed and used as
compost, the latrine is then relocated once more and the old pit re-used.
Figure 5: Fossa Alterna toilet [Illustrator: Peter Morgan; Source: Winblad and Simpson-Hébert, 2004]
Urine Diversion
Many ecological sanitation systems separate the urine component of the waste from the
faeces. Urine contains more nutrients and less pathogens but if it is mixed with faeces it will
require treatment before use as a fertiliser. Although urine diversion does not always occur it
can bring a number of benefits, including (Winblad and Simpson-Hebert, 2004):
4