The effect of alkali pretreatment of rice straw for anaerobic digestion

The anaerobic digestion is an efficient utilization way of crop residues and alkali pretreatment are often used to enhance the degradation. Alkali pretreatment based on Ca(OH)(2) addition of rice straw was studied.The tests of 3 g/l, 9 g/l Ca(OH)(2) addition had an significant effect on enhancing solubilization and rapid acidification, the results were 1521.2 gCOD/l and 935 ml biogas yield of 3 g/l Ca(OH)(2) addition, 1600.7 gCOD/l and 1200 ml biogas yield of 9 g/l Ca(OH)(2) addition, compared to 405.5 gCOD/l and 1162 ml of control(0 g/l Ca(OH)(2) addition). The results also showed that tests of 15 g/l, 21 g/l of Ca(OH)(2) addition were entirely inhibited to biogas yield. The result of the present work implied that although alkali pretreatment to rice straw can significantly enhance solubilization, the inhibition to methane yield was liable to occur.