Measurement of specific resistance to filtration of sludge by pressure filtration

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 R_p measured with pressure filtration method (PFM) has a good consistency with SRF R_v 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 R_m(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 R_m(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.