超声预处理对污泥电脱水特性的改进

探讨超声波预处理对污泥电脱水性能的影响,并找到超声波预处理能够对电脱水产生促进作用的最佳工况。以天津市纪庄子污水处理厂的污泥为研究对象,采用自制的超声预处理电渗透污泥脱水装置进行试验,考察超声波声强和作用时间等因素对污泥电脱水效果的影响。试验开始前对污泥在0.1 MPa压力下进行机械预压0.5min,使污泥挤压密实,以保证电流和超声波在污泥介质中能够均匀平稳地流通。在整个脱水过程中机械压力恒定在0.1 MPa,总作用时间为5.5 min;电脱水过程中电压控制在60 V(泥饼厚度为2 cm),总作用时间为5 min。结果表明,在固定频率20 k Hz、相同电场和压力场作用下,适当的超声波声强和预处理时间能够对电渗透脱水产生积极作用,且超声预处理的最佳作用工况为声强0.510 W/cm2(功率40 W),超声预处理3.5 min。在最佳作用工况下,污泥脱水率达到24.35%,同时减缓了电流的衰减速率,增强了电脱水的效果。

On the innovative improvement of the electro-osmotic dehydration of the sludge through ultrasonic pretreatment

This study investigates the impact of the ultrasonic pretreatment on the function of electro-osmotic dehydration while identifying the optimal working condition by taking.Tianjin Jizhuangzi sewage treatment plant as a sludge dehydration case study sample.In our investigation,we have made an analysis of the impact of the ultrasonic intensity and treatment time on the sludge dehydration with the particularly developed apparatus.What is more,we have adopted an air compressor to preload the sludge for 0.5 min at 0.1 MPa to ensure the sludge density at the end of the extrusion,for it helps to make the ultrasonic and current processing more smooth and regular.In addition,we have managed to control the entire process of dehydration by regulating the mechanical pressure at 0.1 MPa and for 5.5 min,in the electric field fixed at 60 V with the sludge being in a thickness of 2 cm for 5 min.At the same time,we have also managed to control such parameters,as the total dehydration time,the value of mechanical pressure and its compression time and the voltage of the electric field in hoping to work out the optimistic working condition of the ultrasonic.The ultrasonic beam frequency is 20 kHz.Thus,it can be concluded that under the same electric field and the mechanical pressure,proper ultrasonic intensity and treating time should serve as the key links to optimizing the electro-osmotic dehydration.To be exact,the optimal intensity and treatment time should be set on 0.510 W/cm2 and 3.5 min,under the optimal layout of the above mentioned conditions,when the dehydration rate reached to 24.35％,with the attenuation of the current being retarded and the effect of electro-osmotic dehydration being enhanced.