The effect of ultrasound pretreatment on straw fermentation

The anaerobic straw digestion experiments were carried out by different ultrasonic power and time pretreatment under 37 ℃ for 50 d.Gas production rate,pH value,CH4 content in fermentation process were analyzed,and the straw microstructure was analyzed by the scanning electron microscopy(SEM) to study the efficiency of ultrasonic pretreatment on straw microstructure and gas production rate.The results showed:ultrasonic pretreatment can improve the gas production rate and accumulative gas production of straw fermentation,the gas production rate was improved from 4.54 ml/(g·d) to 6.86 ml/(g·d),increased 51.10%;Ultrasonic pretreatment has no significant influence on pH;the content of methane in biogas increased from 43.83% to 47.86%;the optimal ultrasonic pretreatment condition is ultrasonic power 225 W,pretreatment time 30 min.