Investigation of Treatability of Automotive Industry Wastewaters by Coagulation-Flocculation, Fenton and UV/H2O2

Abstract

In the automotive industry, painting operations have emerged as a major source of environmental concerns. In this study, the treatability of wastewater obtained from the automotive industry painting process was investigated by using coagulation-flocculation, ultraviolet/hydrogen peroxide (UV/H2O2), and Fenton processes. The effects of pH, coagulant, and anionic polymer doses were examined for three different coagulants in the coagulation-flocculation process. Optimal conditions were determined based on chemical oxygen demand (COD) and turbidity removal efficiency. As a result of the study, the optimum conditions for the coagulant identified as ferric chloride, which achieved the highest COD removal of 49.6% and turbidity removal of 74.4%, were determined as pH 8, coagulant dose of 400 mg L-1, and anionic polymer dose of 1 mg L-1. In the second stage of the study, Fenton and UV/H2O2 processes were applied to the effluent of the coagulation-flocculation process to increase the removal efficiency. When the results were evaluated, it was observed that the maximum COD removal efficiency of 63.4% was attained under the conditions of pH 3 and 400 mg L-1 H2O2 concentration applied in the UV/H2O2 process. However, in the Fenton process, a maximum COD removal efficiency of only 51% was achieved. From this study, it can be concluded that the UV/ H2O2 process applied after coagulation-flocculation increases the removal efficiency and can be an alternative and effective treatment process for wastewater from the automotive painting process.