不同工况的低强度超声波处理对活性污泥活性的影响

采用好氧活性污泥为试验材料,以污泥的比好氧呼吸速率(SOUR)、混合液悬浮固体浓度(MLSS)、COD去除率及污泥产率系数λ(ΔMLSS/ΔCOD)为指标,通过对超声频率、声强和作用时间3个参数设计的均匀试验,研究不同参数组合的超声处理对活性污泥的活性和代谢过程的影响.结果表明,采用28　kHz、20　W/L、2　min这一参数组合的超声处理可以有效增强活性污泥的活性,提高COD去除效果,并减少污泥产量.同时还研究了污泥浓度MLSS对超声处理效果的影响.通过单因素多水平试验,确定了适合于最佳超声参数组合的MLSS值.对于本次试验所用污泥,MLSS为3?000　mg/L时,超声处理达到了理想效果.根据试验结果,还对低强度超声波影响活性污泥活性和代谢过程的机理提出了假说性解释.

Various Effects on the Activity of Activated Sludge by Low Intensity Ultrasonic Treatments with Different Parameter Combinations

Aerobic activated sludge was used as experimental material. Specific oxygen uptake rate (SOUR), mixed liquor suspended solids (MLSS), COD ratio and lambda (deltaMLSS/deltaCOD) were taken as experimental indexes to indicate the changes of sludge activity and metabolism. The influences on activated sludge induced by ultrasonic treatments with different parameter combinations were studied by equal-distribution experiments about frequency, ultrasound intensity and irradiation time. The results indicated that the best parameter combination (28 kHz, 20 W/L, 2 min) leaded to an evident enhancement of sludge activity and reduced the sludge production at the same time. MLSS, as a vital factor which influences the ultrasonic treatment, was concerned in this study. To the sludge used in these experiments, the results of multilevel experiments showed that the MLSS of 3 000 mg/L induced to a relative highest performance after ultrasonic treatment with the best parameter combination. This article also hypothetically presented the mechanism of sludge activity enhancement stimulated by low intensity ultrasound.