Enhancement of biogas production from wastewater sludge via anaerobic digestion assisted with biochar amendment

Studies have shown that biochar enhances methane formation due to the presence of redox active moieties and its conductive properties. This study investigated the influence of biochar, which was produced from Douglas fir pyrolysis, on biogas production and microbial community during anaerobic digestion (AD) of wastewater sludge. The results showed that biochar significantly enhances methane (CH4) production rate and increases its final yield during AD. The cumulative highest CH4 production obtaining in cultures with DF500 (biochar from Douglas fir at 500 degrees C) were about 11% and 98% more than the culture without biochar at 37 degrees C and 25 degrees C AD temperature, respectively. At 55 degrees C, the maximum CH4 yield reached 172.3 ml/g COD with DF730, which was about 48.3% more than control culture. The microbial community analysis results showed that biochar could up-regulate the role of micro-ecology especially the methanogens and improve the AD process.