Anaerobic Digestion Pasteurization Latrine: Novel onsite sewage treatment for developing countries

The Anaerobic Digestion Pasteurization Latrine (ADPL) is a self-contained and energy neutral on-site sanitation system using anaerobic digestion of fecal sludge to generate biogas, and then uses the biogas to pasteurize the digester effluent at 65-75 °C to produce a safe effluent. The ADPL is a simple system, with no moving parts and relying on gravity-induced flows. The ADPL was installed in Kenya (2013), Philippines (2015), and India (2015) for full-scale field studies. The ADPLs were monitored for biogas production and temperatures in the pasteurization system. Two Kenya systems provided the greatest duration of results. Digesters produced on average 16 and 12 Lbiogas p-1 d-1. The heating system achieved greater than 5 log reductions of FC (non-detectable) in the sterilization tank using only biogas from the digester. Results from this field study show that anaerobic digestion of minimally diluted fecal sludge can provide enough energy to pasteurize the digester effluent.