The Potential of Anaerobic Digestion for Managing the Organic Fraction of Municipal Solid Waste: The Case of Kisumu City

Abstract

The city of Kisumu, Kenya, generates about 400 t/day of solid waste of which 60% is organic. Most of this waste is deposited in undesignated dump sites, posing an environmental threat from methane emissions. Solid waste management is a major challenge in Kisumu and will worsen as the population grows. This paper explores the practicality of treating the city’s organic waste by anaerobic digestion as a means of waste management and energy production in the form of biogas. Since 1 tonne of organic waste produces 110 m3 of biogas, Kisumu could potentially produce 26,400 m3/day of biogas and as 1 m3 of biogas produces 2 kWh of electricity Kisumu could generate 52,800 kWh/day. In addition, 1 tonne of organic waste emits 1102 kg CO2 equivalent into the atmosphere but when converted to biogas through anaerobic digestion this is reduced to 181kg CO2e. Embracing anaerobic digestion would therefore provide a permanent, viable long-term solution to the management of organic waste with both environmental and economic benefits.

Keywords: Anaerobic digestion, Biogas, CO2 equivalent, Electricity, Environment, Organic waste