Distribution, migration and transformation of siloxanes in environment and its impact on biogas application

Siloxane has become an environmental concern as poly-dimethylsiloxanes are extensively applied. Siloxanes in biogas generated from landfill and anaerobic digestion at wastewater treatment plants must be removed before the biogas is used for electricity generation in case of production of silicon precipitates inside an engine. This paper reviews the updated research results on siloxanes including physical-chemical properties, contaminant sources, migration and transformation in environment, biodegradability, concentration profile in biogas, and current technologies for siloxane removal. The topics of future study are discussed, focusing on mechanism of biodegradation and microbiology.