Synergistic Effects of Anaerobic Co-Digestion of Pretreated Corn Stover with Chicken Manure and Its Kinetics

The pretreatment effects and synergistic effects of anaerobic co-digestion of pretreated corn stover (CS) with chicken manure (CM) were studied. Results showed that the NaOH-H2O2 pretreatment effect on CS was better than urea pretreatment in terms of anaerobic digestion promotion. The highest cumulative methane yield of 332.7 mL/g VS added was obtained from the CS (NaOH-H2O2 pretreated)/CM ratio of 1:3, and the highest cumulative methane yield of 319.7 mL/g VS added was obtained from the CS (urea pretreated)/CM ratio of 1:2. Synergistic effects were found in CS (NaOH-H2O2 pretreated)/CM ratios of 2:1, 1:2, 1:3 and CS (urea pretreated)/CM ratios of 1:1, 1:2. Synergistic effect was not found at CS (unpretreated)/CM ratios of 1:2 and 1:3. Pretreatment of CS can produce synergistic effect on anaerobic co-digestion and increase cumulative methane yield by 6.54–24.65%. Among the four kinetic models, modified Gompertz model was best fitted in describing the methane production during anaerobic co-digestion (R2 = 0.9845–0.9988).