Pretreatment for biogas production by anaerobic fermentation of mixed corn stover and cow dung

Stack-pretreatment is introduced to gain higher biogas production from corn stover through solid state anaerobic digestion. The purpose of this study is to find the effects of naturally microbial pretreatment on stalk lignin, cellulose and hemicellulose degradation, and biogas production. The result indicates that the corn straws which had been stack-pretreated for 20 days decreases of the content of the middle corn straws cellulose, hemi-cellulose and lignin by 5.8%, 16.8% and 5.7% respectively lower than that of the untreated samples.The highest cumulative biogas yield for 60-day digestion was obtained in B group, which was 23.2% higher than that of A group, 29.1% higher than H group and also 40.7% higher than I group. The result indicates the biogas yield of anaerobic digestion of the pretreated corn stover mixed with cow dung is higher than that of the untreated ones mixed with cow dung, and higher than that of the untreated ones alone, also higher than the cow dung alone. The biogas yield of the pretreated corn stover mixed with cow is higher than the pretreated ones with the sludge.

► The fresh harvested corn stover was stacked in open-air, the cellulose, lignin and hemi-cellulose degradation rate had reached 7.5%, 21.8% and 5.1% respectively.
► The experiments indicates the biogas yield of the pretreated corn stover mixed with cow dung was higher than that of the untreated ones mixed with cow dung, and higher than that of the untreated ones alone, also higher than the cow dung alone.
► The methane content of biogas was investigated. The methane content of biogas from the pretreated corn stover mixed with the cow dung was higher than the untreated ones, also higher than the pretreated corn stover mixed with the sludge.