Treatment of effluents of construction industry using a combined filtration-electrocoagulation method

Abstract

Abstract One of the significant sources of water pollution is construction industry as it requires considerable freshwater amounts during manufacturing of concrete, mortars and other construction materials. Vast volume of the used water is discharged back to source of freshwater as extremely polluted effluent (high level of suspended solids and pH), which is categorized as hazardous wastewaters. Therefore, environmental regulations prevent discharging these effluents before conducting adequate treatment. As a result, efficient treatment solutions for these effluents become necessary in the field of construction industry. In this context, this research aims at treating construction industry effluents using an integrated method, which involves adsorption (AD) and electrochemical (EL) techniques, to treat effluents of concentration sites. Turbidity and chemical oxygen demand (COD) were selected as pollutants models due to their wide occurrence in this type of effluents. 200 mg of activated carbon (AC) and four aluminum electrodes were utilized to construct the adsorption and electrochemical units, respectively. Aluminum and AC were used here as they are economically efficient, safe, and have a proven efficiency in waters/wastewaters treatment. The influences of initial pH, retention time (RT) and electrolyzing time (ET) on the removal of COD and turbidity using the new method (AD-EL method) were examined. The results demonstrated the AD-EL decreased COD and turbidity by about 72% and 85%, respectively. The perfect conditions to reach this removal levels were pH, RT and ET of 6, 30 minutes and 20 minutes, respectively.