Performance of Continuous Electrocoagulation Process for Turbidity Removal from Sand Filter Backwash Water

Abstract

The presence of particles such as algae, clay, organic materials and water-soluble substances often create turbidity or color in water. In recent years, electrocoagulation process has attracted an extensive attention due to its advantages. Since sand filters are widely used in water treatment industry and their corresponding backwash water is large in volume, turbidity removal will save water consumption and its recycling. In this study, real samples of backwash water from sand filters of a water treatment plant in Alborz province were collected. The turbidity removal was further evaluated under operating conditions of 6, 12, 18 and 30 V as the exerted voltages, electrode distances of 1 and 1.5 cm, different initial turbidities (391 NTU as sample 1 and 175 NTU as sample 2), iron and steel as the sacrificial electrodes in a continuous electrocoagulation reactor. According to the results, the optimum conditions without considering the process economy was found to be 30 V, the iron electrode and electrode distance of 1 cm and samples 1 and 2 had an effective turbidity removal efficiency of 98.4 and 91.6%, respectively.