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Sanitation · Choose and design blackwater treatment · sanitation-10Consider urine diversion
A urine-diverting toilet sends urine from the front bowl and faeces to the back. Keeping them apart makes faeces easier to dry and keeps nutrients in the urine for use as fertiliser.
How
- Keep the faeces vault dry: no water may enter, and add ash, lime or dry earth after each use to cut odour, flies and pathogens (Eawag Compendium).
- Pipe urine to a sealed, undiluted storage container. Stored urine reaches about pH 9, which helps kill pathogens.
- For larger or shared systems, follow the WHO 2006 storage table: 6 months at 20 °C is listed as suitable for all crops. Shorter or colder storage is only suitable for processed or fodder crops.
- For one household using urine on its own food, guidance cited by SSWM allows use without storage, if at least one month passes between the last application and harvest.
- Work urine into the soil near the ground rather than on leaves, and do not use urine that has been mixed with faeces until it is treated.
- Use smooth, wide pipe and allow for cleaning, as urine forms scale.
Safety: Wear gloves when handling urine or dried faeces and wash hands afterwards.
Sources
- Compendium of Sanitation Systems and Technologies (1st edition). Eawag-Sandec, accessed 2026-11
- Urine Storage. Sustainable Sanitation and Water Management (SSWM) Toolbox, accessed 2026-11
- Guidelines for the Safe Use of Urine and Faeces in Ecological Sanitation Systems (EcoSanRes Fact Sheet 5). Stockholm Environment Institute / EcoSanRes (via SuSanA), accessed 2026-11