This paper shows, how ‘dry fermentation’ (in opposition to ‘wet fermentation’ of agricultural and communal bio-waste as well as sewage sludge) can produce methane from solid biomass in a mixture of night soil collected from dry toilet systems. The one-staged batch process needs no mixing of biomass during fermentation and no adding of water or liquid compounds, as it is necessary in conventional wet fermentation systems. This system is particularly suitable for application in semiarid climates, as the water consumption in the process is very low compared to conventional anaerobic digestion systems and can be recovered from the ecological sanitation system.
KOETTNER, M. ; KAISER, A. ; AVENDANO, M.V. (2003): Dry fermentation biogas technology – a practical approach for closed loop sanitation, waste stabilisation and nutrient recovery. In: Proceeding of the 2nd international symposium on ecological sanitation. 7th-11th April, Luebeck, Germany: , 483 – 490.