But here's a new benefit I hadn't heard of. Apparently they can help save hippos too...
The Center for Rural Empowerment and Environment (CREE) has been working with farmers in the Dunga Wetlands on the Kenyan shores of Lake Victoria. By developing and promoting composting toilets as a means of both sanitation and improving farm fertility, they say, they are able to greatly reduce the pressures on the wetlands which are being exploited for their fertile soils.
Jeremy Hance over at Mongabay has an interesting piece on CREE's work in Kenya and the composting toilet/hippo connection:
The toilets collect and mix human waste with ash. After several months have passed the waste can be safely used as a fertilizer for crops, allowing the villagers to grow more crops without having to convert further wetlands. Furthermore eco-san toilets are also called "dry toilets" as they require no water to work.
According to CREE a local farmer in the area was able to triple his output of tomatoes every three months, in addition to now growing three sacks of cowpeas, three sacks of kale, and 500 onions over the same time period. Another farmer doubled his output of kale, allowing him to sell much of it, and was able to fertilize his land without depending on livestock.
Conservation works best when it keeps people's needs in mind. So this project (created by an organization who's URL is ConservationForPeople.org, by the way) is well worth watching. Anyone know of similar projects elsewhere?