压滤式污泥过滤比阻测定方法

Measurement of specific resistance to filtration of sludge by pressure filtration

根据污泥机械脱水机理,建立了污泥比阻测试模型,设计了一种压滤式污泥比阻测试装置.结果表明:压滤法测得的污泥比阻Rp与布氏漏斗过滤实验测得的比阻Rv具有较好的一致性,两者线性相关系数R2=0.99,最大相对误差为8.0%,最小相对误差为1.0%,平均相对误差为5.0%;滤板开孔率的大小不会影响污泥比阻的测定,但当开孔率小于4.0%时,过滤介质和滤板的阻抗Rm(ε)随滤板开孔率的增加而减小,开孔率大于4.0%时,Rm(ε)与开孔率无关.分析了布氏漏斗测定污泥比阻时有效面积的影响;压滤式比阻测定仪测定污泥比阻时,实验压力的选取以获得适宜的过滤速度为宜,压力的改变对实验结果的影响较小;采用正压法,实验压力很容易维持恒定,通过测定活塞位移随时间的变化测定污泥的比阻,测量精度高,还可直观地反映污泥脱水速度的快慢.

A pressure filtration device was designed based on the principle of mechanical dewatering.A corresponding SRF（specific resistance to filtration） testing model was established.The test results show that SRF Rp measured with pressure filtration method（PFM） has a good consistency with SRF Rv measured with Buchner funnel filtration,whose linear correlation coefficient R2 is 0.99,the maximum and minimum relative error are 8%,1.0% respectively,and the average relative error is 5.0%.The porosity of filtrate plate ε does not affect the measurement of SRF,however,the specific resistance Rm（ε） of filtrate plate and filtrate medium decrease with the increasing of filtrate plate porosity ε when ε is less than 4.0%,while it is constantly equal to the specific resistance Rm（ε） of filtrate medium when ε is greater than 4.0%.The change of experimental pressure has little effect on the SRF.The optimal experimental pressure is chosen to obtain an appropriate filtrate speed when SRF is measured by PFM.The stability of experimental pressure can be effectively guaranteed by PFM.The accuracy of testing results can be improved by PFM measuring SRF via the piston rod＇s displacement versus time.Moreover,the sludge dewaterability can be reflected intuitively and qualitatively.