This study investigated the effect of additional moisture and/or alkalinity on the rate of anaerobic digestion in samples of material obtained from pit latrines. In modified serum bottle tests it was shown that poor gas production rates were observed from all experiments with material collected at the lower part of one pit. Using material from the top layer of a second pit it was shown that experimental bottles produced significant amounts of gas with both the addition of water and the addition of alkalinity. The results supports the motivating hypotheses that moisture content and pH buffering capacity obtained in VIP material are low and may be limiting factors in the rate of stabilisation that may occur in these pits. This implies that increasing the moisture content and alkalinity in the pit has the potential to increase stabilisation rate in the pit when the material is not already well-stabilised.
IWA Publishing 2008.