عنوان مقاله [English]
The effluent from the active sludge treatment plant of Qom Shokoohiyeh industrial flows into surface water and reuse of water in industrial process is necessary. The aim of this study was to investigate the efficiency of aluminum sulfate, chlorofluorocarbons and poly aluminum chloride in removing turbidity and other parameters in industrial wastewater before entering RO in Shokoohiyeh Qom industrial refinery. This study was applied in a laboratory scale using a jar-test and experiments based on varying concentrations of coagulants (200, 400, 700, 800, 1000, 1200 mg/L) and pH=22.214.171.124.8.10 has been done. Steady mixing, slow mixing and stagnation have been performed and factors such as turbidity, pH, COD, BOD5, EC, SVI and TSS have been investigated. Coagulants are effective in removing turbidity. The highest removal rate was for polyvinyl chloride (95%) and the least amount of turbidity removal was in chlorofacry (50%). The highest and lowest levels of pH were detected at pH=2 (72%) and pH=8 (10%), respectively. The lowest BOD5 removal efficiency in poly aluminum chloride was 88% at pH=4 and the highest removal rate of BOD5 was found in chloroformate coagulant with pH=4 (96%). The highest COD reduction was observed in poly aluminum chloride at pH=9 (89%) and the lowest COD reduction was observed at a concentration of 800 mg/L alum with 34%. The highest reduction in electric conductivity in poly aluminum chloride with 87% and the lowest amount of electrical conductivity reduction occurred at a concentration of 500 mg per liter of alum with 12%. The highest total removal of suspended solids in chlorofacrylic coagulant was 88% and the lowest amount was removed in chloroform with up to 18%. The maximum amount of sludge deposited at pH=9 (240 mg/L) in aluminum chloride and the lowest amount of sludge deposited at pH=2 (5 mg/L). The use of coagulant materials can increase the purification efficiency, eliminate opacity and return water to the cycle. PAC and Alum coagulant have high efficiency in removing turbidity and other wastewater treatment parameters that can be used to treat wastewater for RO systems.