Investigation of the Effect of Poly Aluminum Chloride Coagulant with Coagulant Aids for Oily Wastewater Treatment from a Vegetable Oil Factory

The increasing pollution of water and soil in today›s industrial activities becomes a real problem in the world. In the meantime, oily wastewater has adverse effects on surface and underground waters, agricultural products and soil quality. The purpose of this study was to reduce or eliminate pollutants present in the effluent of one of the vegetable oil plants to prevent the accumulation of oily materials in environment. In this regard, effectiveness of using coagulants and coagulant aids as water and oil separation process has been investigated. This method is based on the changing of operational variables such as pH, alkalinity and concentrations of coagulant and coagulant aids. Thus, optimal conditions for effective water and oil separation were determined. Test samples were prepared from a vegetable oil plant. Poly aluminum chloride as coagulant and different coagulant aids have been used. The basic method was jar test in which, the different concentrations of coagulant, coagulant aids, pH and Alkalinity were considered. The best results were achieved at 10 ppm for poly-aluminum chloride as coagulant, 0.3 ppm for Gfloc-C125 as a coagulant aid with alkalinity amount of 75 ppm. The results showed that at optimal condition, the quantities of turbidity, oil, COD and Total Suspended Solids (TSS) for wastewater was decreased 89.4%, 98.8%, 62.6% and 97.9% respectively. The results were in a good accordance with environmental standards for plant irrigation.