Potential for biogas production from anaerobic co-digestion of dairy and chicken manure with corn stalks

Anaerobic co-digestion of dairy manure, chicken manure with corn stalks were investigated at 15, 35 and 55 degrees C. Two trials were carried out, one based on co-digestion of dairy or chicken manure alone with corn stalks at ratios of 1:1, 2:1 and 3:1, the other based on co-digestion of dairy and chicken manure together with corn stalks on the premise of the optimal ratio between manure and stalks. In the first trial, the analysis based on the biogas and methane yields showed that co-digestion of dairy or chicken manure with corn stalks at 2:1 both had higher fermentabilities than other ratios. In the second trial, at 15 degrees C and 35 degrees C, various ratios of co-digestion of dairy and chicken manure together with corn stalks were all higher than co-digestion of two kinds of manure alone with corn stalks and maximum biogas and methane yields were obtained at the C/N ratios from 25 to 28. At 55 degrees C, only at the mixture ratios of 1.6:0.4:1, co-digestion of dairy and chicken manure together with corn stalks were higher than co-digestion of dairy manure with corn stalks, indicating the optimal C/N ratios from 28 to 30 in biogas and methane production. Based on regression analysis, maximum biogas and methane yields were found at 49.9 degrees C and 46.9 degrees C with the ratios of dairy, chicken manure and corn stalks at 1.14:0.86:1 and 0.74:1.26:1, respectively.