Dewatering of a biological industrial sludge by electrokinetics-assisted filter press

The objective of this work was to evaluate the performance of biological industrial sludge dewatering by a pilot-scale filter press assisted by electrokinetics (EK). In all experiments the following conditions were kept constant: (1) dry solids content in the sludge feed: 5.0 wt%; and (2) constant electric-current mode. Application of 1 A and 4 A of electric current for 45 min for dewatering was capable of yielding sludge filter cakes with moisture contents of 65.0% and 53.2%, respectively. However, the former would provide a better compromise between the residual moisture content and the electricity cost. This practice has been shown to be cost-effective. The reduction of sludge moisture content might be ascribed to the mechanisms of mechanical pressure, electroosmosis, and ohmic heating in said dewatering system. The estimated electroosmotic permeability was found to be comparable to that of reported by other researchers.

Figure optionsDownload as PowerPoint slideHighlights
► EK-assisted pilot scale filter press can reduce the sludge moisture content to 53.2%.
► Reducing the sludge moisture content to 65% by electrodewatering is cost-effective.
► Mechanical pressure, electroosmosis, and ohmic heating are major mechanisms involved.