Evaluation of Wastewater Reuse with Coagulation/Flocculation Process in Pesticide Production

Pesticide industry wastewater causes toxic effects and bioaccumulation and high chemical oxygen demand (COD) and suspended solids (SS) concentrations of these wastewaters cause environmental problems. Furthermore, the wastewater caused from pesticide industry indicates great alteration in the wastewater characteristics subjected to the kind of agrochemicals produced and on the use of materials manipulated. In this study wide found and economical coagulants; ferrous (III) chloride, alum, ferrous (II) sulphate, and also a polyelectrolyte magnafloc were used for a physicochemical treatability study and reusing of the wastewater was evaluated. SS and COD removal was ensured with coagulation and flocculation process, however, it was seen that this process was not sufficient for discharging to receiving water environment. The optimum pH values for iron (III) chloride, alum and iron (II) sulphate were found to be 7.21, 8.12 and 7.18, respectively and optimum coagulant dosages were 250 mg/L for iron (III) chloride and iron (II) sulfate, and 300 mg/L for alum. The COD removal efficiencies were 43%, 47% and 42% for iron (III) chloride, alum and iron (II) sulphate respectively and also SS removal efficiencies were 44% for iron (III) chloride, 47% for alum, and iron (II) sulphate for 39%. Optimum polyelectrolyte doses were determined to be 0.2 mg/L for alum and iron (II) sulfate and 0.3 mg/L for iron (III) chloride. Consequently, it was ascertained that the wastewater originated from pesticide industry could be reused in production after the coagulation/ flocculation process.