超声预处理对剩余污泥酶活性的影响

为了研究不同工况下超声波预处理对剩余污泥酶活性变化的影响，对剩余污泥进行不同输入能量、频率的超声预处理，测定了预处理后污泥蛋白酶和脱氢酶的变化规律。结果表明：1）超声预处理在低能量输入条件下对污泥蛋白酶和脱氢酶活性存在促进作用，而随着超声能量的进一步增加，酶活性逐渐降低直至出现抑制现象；2）超声频率对污泥酶活性影响较为显著，其中20 kHz超声频率对蛋白酶和脱氢酶活性的促进效果最高，其次分别为25和33 kHz；3）当输入能量高于8 000 kJ·（kg TS）-1后，25和33 kHz频率超声预处理对污泥蛋白酶和脱氢酶活性存在抑制效应，引起该现象的原因分析可能是高频超声空化现象及伴随的热化学效应引起的生物酶失活导致的。

The effects of ultrasonic pretreatment on enzyme activities of waste activated sludge

To study the influence of ultrasonic pretreatment of waste-activated sludge (WAS) floc on enzyme activity, experiments were performed at various ultrasonic-specific energies and frequencies. Protease and dehydrogenase activity in WAS was examined. The activity of these enzymes increased with increasing ultrasonic-specific energy, then decreased and stabilized. At an ultrasonic frequency of 20 kHz, both the activity of protease and dehydrogenase increased at various ultrasonic-specific energies. Where the ultrasonic frequency increased to 25 and 33 kHz, the activity of the abovementioned enzymes decreased when ultrasonic-specific energy was over 8 000 kJ·(kg TS)-1. This might have been caused by a thermal-chemical effect followed by cavitation during ultrasonic pretreatment, leading to enzyme inactivation.