A new combined electrocoagulation-electroflotation process for pretreatment of synthetic and real Moquette-manufacturing industry wastewater: Optimization of operating conditions

Abstract Moquette-manufacturing industry produces wastewaters containing high-concentrations of polyvinyl acetate (PVAc), which is highly toxic and can inhibit the activity of microorganisms in biological wastewater treatment plants. In the present study, a new combined electrocoagulation-electroflotation process was used to treat the high organic load wastewater of the moquette manufacturing industry. For this purpose, the efficiency was evaluated on the basis of the removal of chemical oxygen demand (COD), total suspended solid (TSS), PVAc, total dissolved solid (TDS) and electrical conductivity (EC) from the synthetic and real wastewater. The results showed that process efficiency increased with increasing current density (CD) and retention time and with decreasing electrode distant. Under the optimum conditions (electrode distance =1 cm, reaction time = 20 min, pHo = 7, CD = 22 mA/cm2), the removal efficiencies of COD, TSS, PVAc, TDS and EC for the synthetic and actual wastewater were 84.8, 81.9, 91.6, 68.7 and 76.4 and 93.9, 92.9, 95.9, 90.5 and 85 %, respectively. In addition, the iron electrode is preferred to the aluminum electrode because of its higher efficiency, lower cost and lower electrical energy consumption. It was found that this process facilitated the floatation and compaction of the flocs at the surface of the electrochemical reactor and finally eliminated the need for the sedimentation/flotation unit.