Effect of Ultrasonic Pretreatment on Biogas Production from Rice Straw

The effect of ultrasonic pretreatment on biogas production from rice straw was investigated. Results showed that the application of 37 and 102 kHz resulted in a reduction of hemicellulose about 25.78% and 20.82%, respectively. An increase in the power level and exposition time decreased the hemicellulose content. The biochemical methane potential values at 37 kHz and 102 kHz of the pretreated rice straw for a period of 45 days were 250.36 and 243.79 mL CH4 g VS-1added, which were about 21.95% and 18.75% increase compared to the unpretreated one, respectively. The pretreatment with 37 kHz has provided a better methane yield compared to the one with 102 kHz. Response surface methodology indicated a positive result toward the methane yield and production rate. The utilization of ultrasonic pretreatment toward rice straw for biogas production seems to provide a solution to help solving the problems of both agricultural waste and renewable energy.