Treatment of Food Processing Industry Wastewater by a Coagulation / Flocculation Process

Food processing industry wastewater poses pollution problems due to its high COD (Chemical Oxygen Demand) and BOD (Biochemical Oxygen Demand). Moreover the characteristics of wastewater depict wide variation due to the variation in the type of products manufactured and also the different fruits, vegetables and raw materials used. Many preservatives, colour, salts, oil, sugar, gelatin etc are added as per the requirement of production of various products, this adds to the pollution load. Because of these problems, the load on conventional treatment unit which employ anaerobic and aerobic reactors for the treatment generally malfunctions. It is therefore preferable to provide primary physicochemical treatment, using different coagulant and coagulants aids thus reducing the organic load on secondary biological treatment. Keeping this in view commonly available coagulants like lime, alum, ferrous sulphate and ferric chloride and few different polyelectrolytes as a coagulant aid were studied. Being acidic in nature this wastewater was treated by two stage physicochemical treatment. Results indicated that this wastewater is amenable to physicochemical treatmen