超声辅助对污泥电脱水的特性改进

Characteristics improvement of ultrasonic for electro-dewatering sludge

采用自制的超声波辅助电场污泥脱水装置进行实验,考察了超声波声强和作用时间等因素对污泥含水率的影响。结果表明,在固定频率20 k Hz条件下,在相同电场(电压60 V,作用时间5 min)和压力场(压力0.1 MPa,作用时间5.5 min)作用下,通过变换超声波声强和作用时间,得出最优处理条件为声强0.255 W/cm2,作用时间3.5 min。为了消除初始含水率与系统误差的影响,将脱水率作为比较各作用工况的重要指标。在上述最佳工艺条件下,污泥含水率由83.26%降低至72.90%,与单纯电渗透脱水相比,脱水率由4.88%增大到12.44%,同时减缓电流衰减的速率,增加电渗流量上升速率,增强了电渗透脱水效果。

This paper presented a laboratory study on electro-acoustic dewatering （EAD） of sludge with purposely designed apparatuses. During the dewatering tests, water content electro-osmotic flow rate and curremt were measured as an evaluating indicator. The study showed that 20 kHz is the optimum frequency to sludge de- watering. Hence,20 kHz was fixed parameter. On the basis of the measurements, the influences of ultrasonic in- tensity and treatment time were analyzed. The results showed that the optimum processing conditions were a inten- sity and treatment time of 0. 255 W/cm2 and 3.5 min under the same electric field, where voltage was 60 V and treatment time was 5min,where pressure was 0.1 MPa and treatment time was 5.5 min. In order to eliminate the interference of the initial sludge water content and systematic error, sludge dewatering rate was an evaluating indi- cator. Under the optimal conditions mentioned above,sludge water content decreased from 83.26% to 72.90%. When regarding electro-dewatering,sludge dewatering rate increased from 4.88% to 12.44%. Moreover, energy consumption only increased 1.6%. It resulted in retarding attenuation of current and enhancing decrease of elec- tro-osmotic flow rate. Hence, apt ultrasound is favorable to the EDW.