Pollutants Removal From Domestic Wastewater Using Electrocoagulation/Electro-oxidation Method

The excessive presence of phosphate and ammonium in the wastewater promotes eutrophication, which will result in an anarchic proliferation of algae. This phenomenon affects lakes, rivers, reservoirs and coastal areas, causing one of the most serious problems of water pollution in recent years. Thus, to control the eutrophication, removal of phosphorus and ammonium is necessary. The aim of this work is to optimize the efficiency of the electrocoagulation process(EC) to remove nutrients like phosphorus, ammonium and COD from synthetic wastewater, and then apply the optimization for real wastewater treatment. The work was conducted in two steps. In the first step, phosphorus was treated using iron and aluminum electrodes. In this step, several parameters were considered, namely distance between electrodes, initial p H, initial concentration, current density, COD, NH4+-N and the addition of Na Cl. The removal efficiencies of phosphorus were found to be 92.2%, 92.0% and 89.0% corresponding to 1cm, 2cm and 5cm of the distance between electrodes. The evaluation of the p H showed that the removal efficiency at p H of 3 was better, but to avoid too acidic environment, a solution at p H of 5 was considered and the phosphorus removal efficiency was 89.2% at 55 minute. It was also observed that at low initial concentration phosphorus removal efficiency increased to 93.0% with time and it increased from 61.0% to 89.2% with the increasing current density from 8.68 m A/cm2 to 13.88 m A/cm2, respectively. It was also observed that the phosphorus removal efficiency slightly increased from 89.2% to 91.0% with the increasing NH4+-N and COD. The removal efficiency of phosphorus by the aluminum electrode without optimization of the parameters was 77.0%. The results showed that phosphorus removal efficiency at optimal initial p H, initial phosphate concentration and COD were 93.0%, 93.0% and 90.3% after 55 min with 0.8 A, respectively. According to the results it was found that the aluminum electrode was better than the iron electrode in the removal of phosphorus. In the second step a comparative study between the electrode of Cu/Zn, Cu and Fe as cathodes was conducted for the electrochemical treatment of ammonium. We studied the effects of different electrodes as cathodes, the presence and absence of Na Cl and the effect of temperatures such as 20°C, 30°C and 40°C on ammonium from real wastewater. It showed that optimal ammonium removal efficiency was obtained(approximately 100%) after 30 minutes under optimal conditions which were Cu/Zn with a current density of 18.32 m A/cm2, space between electrodes of 1.1 cm, a temperature of 40°C, an amount of 0.5 g/L of Na Cl and the COD concentration in municipal wastewater of 185 mg/L. It was proved that there was the great optimization of phosphorus and ammonium removal by this electrochemical process.