Anaerobic digestion of straw after microwave pretreatment with acid

High-energy biogas was generated through anaerobic digestion of straw pretreated with acid and microwave energy.In laboratory experiments,the pH,gas production rate and concentration of methane in the gas were monitored.The main conclusions are:① There was an obvious effect of microwave acidification pretreatment on the efficiency of anaerobic digestion of the straw.The average accumulated gas production from non-pretreated and pretreated straw amounted to 186.1 and 245.4～303.4 mL·g-1,respectively,a significant increase after pretreatment.The maximum daily gas production was also increased to 14.11 and 18.64 to 33.19 mL·g-1·d-1,respectively,and was reached after a distinctly shorter period of time(12 d for non-treated straw,but 4 to 11 d for the pretreated straw).② The CH4 concentration in the biogas increased from 52.1% to 64.5%,which is equivalent to an increase in bio-energy yield from 19.71 to 24.41 MJ·m-3.Furthermore,the extent of mineralization was increased from 44.1% to 64.25%.