Treatability of Carwash Wastewater by Application of Combined Chemical Coagulation and UV/H2O2 Processes

Abstract

In recent years, the increase in car production, population growth, urbanization and significant expansion of the use of private vehicles has led to the development of more and more carwash facilities in all cities. Regarding the carwash wastewater pollutants, treatment of such wastewater can be a big help in protecting surface and groundwater resources. The wastewater needed for this research was taken from the output of carwash using hand washing method and composite sampling. The aim of this study was to determine the efficiency of combined chemical coagulation and UV/H2O2 processes in treatment of carwash wastewater. To reduce the settleable solids, samples underwent a 2-hour settlement. Then in the first step of coagulation process, the optimum conditions for pH and the ferric chloride dose were obtained using jar test. The effluent of coagulation stage was introduced to UV/H2O2 reactor under the influence of ultraviolet radiation. Finally, required parameters such as COD and BOD5 in the effluent of oxidation process were measured at the designated times. Results showed that the COD removal efficiency of 70% and 93.2% was achieved in coagulation and UV/H2O2 process, respectively. The overall efficiency of this system based on COD and BOD5 removal was obtained as 98% and 97.5%, respectively. Overall, the recommended combined system is effective and robust to treat carwash wastewater to meet the standards of effluent discharge.

Keywords

• Carwash
• Effluent
• Chemical Coagulation
• UV/H2O2