Effective Mesophilic Anaerobic Digestion Of Wheat Straw And Rice Straw For Biogas Production

Bioenergy, a kind of renewable energy, plays a more and more important role in the worldwide clean energy consumption. In 2003, approximately 0.7 billion tons of corp waste were generated in China, which are very good materials to yield methane —bioenergy.However, little research has been conducted on the anaerobic conversion of straw to methane. The main reason is the raw materials of wheat straw and rice straw contain high percentage of lignocelullose, which isn't readily biodegradable by anaerobic bacteria.In the former experiments, Fungi P.Florida and chemical NaOH have been used to pretreat the straw to destroy the microstructure of lignocellullose, which are believed to be effective to improve the performance of the anaerobic digestion of the straw. This study investigated the effects of biological and chemical pretreatments on biogas production of straw at 4 different loading rates(35g/L, 50g/L, 65g/L, 80g/L).The experimental results showed that the NaOH pretreatment could effectively improve the anaerobic digestion performance of wheat straw, whereas the fungi pretreatment hasn't got the same trends. After 30 days of NaOH pretreatment, the peak amount of biogas increased by 67%, the retension time reduced by 38%, the biogas yield per VS load increased by 43%, and the starting of biogas production advanced from the 7^th day to the 4^th day. The percentage of the methane in the biogas and the fertility of the sludge also increased.The experimental results also showed that the fungi pretreatment and the NaOH pretreatment could both effectively improve the anaerobic digestion performance of...