TECHNOLOGY > ECOSAN
Sketch showing principle of urine
EcoSan (Ecological Sanitation)
Many cultures have understood the value of urine and faeces for agricultural purposes for centuries, and latrine designs based on the concepts of ecological sanitation have been used in Asia and parts of Africa for hundreds of years.
So far, Ecological Sanitation (Ecosan) has made little progress in Africa despite decades of promotion by donors. The practical and environmental benefits of ‘closing the loop’ (i.e. recycling the nutrients in excreta) seem remote to most poor African households. There are, however, a number of physical conditions – including high water table and hard rocky ground - which can increase the comparative advantage of many forms of Ecosan technology.
Eco-sanitation is based on three main principles:
- It offers a safe sanitation solution that prevents disease and promotes health by successfully and hygienically removing pathogen-rich excreta from the immediate environment.
- It is environmentally sound as it doesn’t contaminate groundwater or use scarce water resources.
- It creates a valuable resource from what is usually regarded as a waste product.
A person produces about 500 litres of both faeces and urine in a year and human urine contains about the same levels of Nitrogen, Phosphorus and Potassium as commercially produced fertilisers.
Ecological sanitation closes the loop of nutrients.
Skyloo build with local materials
in Maseno District.
Attributes of EcoSan Toilets
- Minimal use of water
- Dehydration/aerobic composting (with or without urine separation)
- May require drying/bulking material (ash, dry soil, lime, crushed sea shells etc.)
- May be above ground to facilitate contents removal
- Nutrients and sanitized excreta as end-products
Types of EcoSan Latrines in Kenya
In the late nineties Kenyan NGOs indtroduced three types of EcoSan latrines:
- Skyloo: a raised latrine with urine diversion and separate collection of urine and faeces in a permanent structure that requires periodic (6-12 months) emptying of the receptacle and transportation to a composting site.
- Arborloo: a portable superstructure and no urine diversion covering a shallow pit that fills in approximately one year after which the superstructure is moved and a tree can be planted in the filled pit.
- Fossa Alterna: two permament pits and a portable superstructure, so that when one pit is full the superstructure is moved on top of the other pit. The digested contents of pit not in use can be safely emptied after a year.
Fossa Alterna and Arborloos work best when quantities of soil, wood ash and leaves are added periodically to produce a balanced compost. Skyloos require some ash to dry the faeces and increase pathogen destruction.
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Description of projects where EcoSan is implemented by KWAHO: