Effects of Piecewise Electric Field Operation on Sludge Dewatering: Phenomena and Mathematical Model

Electro-dewatering (EDW) is an energy-efficient method for sludge dewatering. In this study, effects of piecewise electric field operation on EDW were investigated by experiments and simulation. Operational parameters were studied mainly in terms of sludge resistance variation during electro-dewatering process, which were evaluated by linear sweep voltammetry (LSV) analysis. Simulation of the sludge cake electro-dewatering processes was developed and validated, based upon time-dependent experimental data of electric currents and filtrate weights. The modeling results were in good agreement with experiments. It was proved by experimental and modeling results that the piecewise operation has positive effects on key performances of EDW devices, that is, limited water content, space-time yield, and mass specific energy consumption.