Thickening of Biological Sludge by Electro-Coagulation-Flotation Process

摘要

The present study is to investigate the thickening of hospital wastewater biological sludge by theElectro-Coagulation-Flotation (ECF) process. The electrochemical thickening of biological sludge hasbeen studied by batch electrolysis experiments under different conditions. The various parameters like-2 effect of pH (2-11), current density (0.5-3 mA cm ), and reaction time (2 to 60 min) on increase ofsludge suspended solids concentration and also the removal efficiencies of Chemical Oxygen Demand(COD) and turbidity from the biological sludge were studied. The results indicated that the maximumCOD and turbidity removals were achieved in acidic pH level and electrolysis time of 30 minutes.-2 With increasing current density from 0.5 to 3 mA cm at the optimum conditions of operation, theremoval efficiencies of COD and turbidity reached from 65.1 to 75.6% and 56 to 96.4% respectivelyduring the ECF. In addition, in the above-mentioned conditions, suspended solids concentrationincreased to 2.1 percent. Mean energy consumption and current efficiency were figured at about 0.03-3 kWh m and 200%, respectively.