Characterization and treatability of automotive industry wastewater

Environmental pollution caused by industrial activities is one of the most important problems of today. The automotive industry, on the other hand, is an important sector for the country's economy with a high export capacity and employment. The treatment of wastewater originating from this industry is important both for a sustainable production and from an environmental and economic point of view. In this thesis, the treatability of automotive industry dyeing process wastewater using coagulation flocculation, ultraviolet/hydrogen peroxide (UV/H2O2) and Fenton (Fe2+/H2O2) processes was investigated. It is aimed to determine the conditions in which optimum removal efficiencies are obtained for each process throughout the study. In this study, alum (Al2(SO4)3·18H2O), ferrous (II) sulfate and ferric (III) chloride (FeCI3·6H2O) coagulants and anionic polymer, which are widely and economically used, were used. The optimum pH values for alum, ferric (III) chloride and ferrous (II) sulfate are 7,9,8 respectively and the optimum coagulation dosages are 400mg L-1 for ferric (III) chloride and ferrous (II) sulfate and 120 mg L-1 for alum was found a. COD removal efficiencies are %49.6 %44.6 and %44.6 for ferric (III) chloride, alum and ferrous (II) sulfate, while turbidity removal efficiencies are %74.4 for alum, %50.3 and %80.2 for ferrous (II) sulfate. Optimum anionic polymer doses were determined as 0.25 mg L-1 for alum, 1 mg L-1 for ferric (III) chloride and 4 mg L-1 for ferrous (II) sulfate. It has been observed that COD and turbidity removal are also provided by the coagulation flocculation process, but it is not sufficient for discharge into the receiving environment. In line with the results obtained, it is aimed to determine the contribution of the coagulation flocculation process on the increase efficiency by applying the UV/H2O2 and fenton processes, one of the advanced oxidation processes, separately to the process effluent, which is carried out under optimum conditions. When the results were evaluated, the maximum COD removal efficiency was obtained as %63.4 of the UV/H2O2 at pH=3 and 400 mg L-1 H2O2 concentration. As a result of the study, although a total COD removal efficiency of 63.4% of the wastewater was obtained, the discharge standards could not be met. However, the use of alternative treatment methods can enable compliance with discharge limits.