Methane Potential of Municipal Sludge in Anaerobic Co- Digestion Process Boosted With Glycerol

Abstract

As a renewable resource, the production of biogas is increasingly valued by various countries in the world. The goal of this thesis was to study the methane potential of municipal sludge in the anaerobic co-digestion process boosted with waste glycerol. The municipal sludge was obtained from the wastewater treatment plant Lehtoniemi (Kuopio Vesi) in Kuopio, Finland. The study compares the methane potential of municipal sludge and same feeding material boosted with glycerol as raw materials in the anaerobic co-digestion process to produce biogas, and compare the performance of biogas produced from different sources. Two materials were used for the experiment, which were municipal sludge and waste glycerol from biodiesel production. Municipal sludge is an experimental sample, and it requires determining methane potential. The inoculum was mixed with municipal sludge in a reactor to get the anaerobic digestion process started properly. According to the results of the experiment, for municipal sludge without glycerol 11 Nm3 methane can be produced (per 1000 kg fresh mass). For municipal sludge boosted with glycerol 22 Nm3 methane can be produced. In general, the municipal sludge added with 1% glycerol produces almost 100% more methane compared to sludge without glycerol. This study shows that boosting municipal sludge with glycerol in the anaerobic co-digestion process has a good potential for increased methane yield.