低强度超声波强化剩余活性污泥好氧消化的研究

Enhanced aerobic digestion of waste activated sludge by low intensity ultrasound pretreatment

污泥是城市污水处理厂的副产物,若处理不当,将会带来一系列严重的环境问题。实验采用低强度超声波对剩余活性污泥(WAS)的好氧消化过程进行强化,选取超声强度、超声时间、超声间隔3个因素设计正交实验。结果表明,经超声辐照的WAS,其好氧消化时间最短仅约为13d,比未经超声辐照的缩短了18.00d。对实验结果的极差分析和方差分析表明,低强度超声波强化WAS好氧消化的最佳参数为:超声强度1.0W/cm2、超声时间10min、超声间隔8h。实验还研究了WAS达标前后溶解性化学需氧量(SCOD)和总化学需氧量(TCOD)的变化情况,发现在相对较短的处理时间内,经低强度超声波强化处理的WAS的TCOD降解率仍然能与对照相近甚至高于对照,主要原因是低强度超声波强化了微生物的新陈代谢,促进了其对有机物的吸收分解。

Minimizing the sludge production is an important task for many biological wastewater treatment plants. The experimental results of this study have demonstrated that low intensity ultrasonic treatment of the waste activated sludge （WAS） made it more ready for aerobic digestion. An experimental program of orthogonal design was carried out to determine the most effective treatment conditions of the ultrasound intensity, treatment time and the treatment interval that would have the most benefit on aerobic digestion. The ultrasound treatment, employing an ul- trasound intensity of 0.4 W/cm^2 for 15 min of treatment every 8 h, reduced the time required for equivalent aerobic digestion of WAS t.o 13 days, 18.00 days shorter than the time required without the ultrasound treatment. The ultrasound treatment enhanced the metabolic process of the microorganism in the WAS making them more active for aerobic digestion. It is an attractive sludge pretreatment process.