Influence Of Ultrasonic Disintegration On Methane Production In Anaerobic Digestion Of Municipal Sludge

The subject, relying on projects of ultrasonic disintegration to enhance anaerobic digestion of municipal sludge in the Dalian sludge treatment plant, studys the effect of ultrasonic disintegration on daily gas production, daytime hours gas production, methane content, VS degradation rate, gas generation rate etc., as well as the start of anaerobic digestion, the stop and then restarting of anaerobic digestion, the gas production performance anaerobic digestion in the subsequent dosing raw sludge, and provides the data basis and technical reference for the practical application of ultrasonic disintegration sludge technology.In the field test, the frequency of ultrasonic equipment was20kHz, and power was set to300W. The time of ultrasonic disintegration was set to90s/5L.The same ultrasonic sludge was dosed in digestion tanks to start the anaerobic digestion before11-day comparison test on gas production. In the dosing rate of5%, the gas production increased by76%after dosing ultrasonic sludge. And in the subsequent10-day test dosing equivalent of the raw sludge, the effect of ultrasonic disintegration improving gas production was still continuing and strengthened.The same raw sludge was dosed in digestion tanks to start the anaerobic digestion, followed by45-day ultrasonic sludge comparative test in the dosing rate of5%. The effect of ultrasonic sludge on daily gas production, daytime hour’s gas production, methane content, VS degradation rate, gas generation rate etc. were respected in the comparative test. The results showed that:When gas productions of the two tanks was stable, the average daily gas production, the VS degradation rate, methane content, methane production were increased by18.8%,64.1%,3.9%,23.6%,respectively, after dosing ultrasonic sludge, and anaerobic digestion performance was strengthened. The ultrasonic disintegration promoted protein hydrolysis and methanogenesis, the gas production of degradation1gVS decreased by23.8%. In the first day, the11th day, the16th day of dosing ultrasonic sludge, the time when the gas production rate was greater than dosing during the day were the first2hours, respectively, the first6hours, all nine hours, respectively. The dosing ultrasonic sludge digestion tank and dosing raw sludge digestion tank stopped running for three days and then wer restarted, followed by a comparison test of gas production. The dosing raw sludge digestion tank had no gas production after stop running for three days. Gas production performance of the dosing ultrasonic sludge digestion tank was still good and had higher gas production after stop running for three days.Ultrasonic disintegration technology can improve gas production and methane production and can optimize the resources of municipal sludge. And VS degradation rate is increased, which conduce to sludge reduction. According to the observation the energy consumption ratio of ultrasonic disintegration technology, to analyze the increase of net energy output value of the anaerobic digestion.