Method Development for the Synthesis of Anaerobic Digester Biogas with the Laboratory Environment

Biogas, a gaseous mixture produced during decomposition of organic matter, is a renewable, easily generated and common byproduct of anaerobic digestion at wastewater treatment plants (WWTP), landfills and agricultural operations. There is growing interest in researching and utilizing the energy potential associated with its combustion. Siloxanes, a family of volatile organic silicon compounds, pose large impediments to biogas usage due to the formation and precipitation of silicon dioxide within combustion devices. Removal of siloxanes prior to combustion is therefore a growing endeavor. Research was performed to synthesize a representative gas stream produced from anaerobic digesters within WWTP. Methane, carbon dioxide and hydrogen sulfide were combined with humidity and gaseous siloxane in levels characteristically seen exiting anaerobic digesters. A methanol impinger train was utilized to sample the biogas composite. Gas chromatography-mass spectrometry (GC-MS) was used to determine gas-phase siloxane concentrations in the gas stream effluent for the purposes of confirming the generation of a consistent and reproducible biogas stream.