Influence of biogas digesters on faecal indicator organisms in digestate and around homesteads in Ethiopia

• Published in: Biomass & bioenergy 2020-11, Vol.142, p.105746, Article 105746
• Main Authors: Nakamya, J., Tumuhairwe, J.B., Sabiiti, E.N., Strachan, N.J.C., Avery, L.M., Smith, J.
• Format: Article
• Language: English
• Subjects: Bio slurry; Biogas digester designs; Environment; Faecal indicator organisms
• ISSN: 0961-9534; 1873-2909
• DOI: 10.1016/j.biombioe.2020.105746

It is important, prior to application of organic wastes to land, that pathogen loads are reduced sufficiently to minimize dissemination to the wider environment. Anaerobic digestion for biogas production is a low-cost method to reduce pathogens in agricultural wastes that provides the added benefits of energy generation. There have been claims of pathogen reduction following installation of biogas digesters in homesteads in Sub-Saharan Africa. Homestead pathogen levels following installation of the different designs of biogas digester were monitored using faecal indicator organisms within small rural farms in Ethiopia. However, different designs of digesters have registered varying levels of success. Of the three digester designs considered, fixed dome, floating drum and flexible balloon, the fixed dome design achieved the highest reductions in indicator organisms (coliforms, Escherichia coli and Enterococci) from feedstock to digestate; this is likely to be due its longer hydraulic retention time. Households with biogas digesters installed had significantly (p