Safety and Nutrient Values (NPK) of bio-effluent from human excreta used to feed biogas plants in Rwanda

Abstract

Compared to cattle dung, human excreta have been used for methane generation in limited scale in most of developing countries. In Rwanda, institutions and households which have biogas plants connected to toilets are producing big quantity of bio effluent every day. It is not known whether such bio effluent is a rich fertilizer and safe for human health. This scientific research study was conducted in the four provinces of Rwanda where biodigesters connected to toilets are installed and operating. Field sites visits were made, samples were collected in sterilized bottles, transported in cooling boxes and taken to Laboratory for analysis. Laboratory results obtained revealed that bio effluent from human excreta digested in biogas plants connected to toilets is a rich natural fertilizer and it does not contain harmful bacteria (Shigella and Salmonella). Thus, use of this bio effluent could have a major impact on food security, agribusiness, agro-industries and may constitute a source of income.

Keywords: Bio-effluent (NPK), Biodigesters, Human excreta, Toilets, Bacteria, Food security