Physicochemical Treatment of Distillery Wastewater-A Review

A distillery industry which represents an important segment of the world economy is amongst the highly polluting industries after the paper industries. Spent wash (SW) generated from distilleries have a very high chemical oxygen demand (COD) (i.e., 20,00050,000 mg/dm(3)) and biological oxygen demand (BOD) (i.e., 7000-50,000 mg/dm(3)), while the COD and BOD values depend on the raw material used. If it is discharged to water-receiving bodies without treatment, it may damage the aquatic system. Apart from causing water pollution, unpleasant odor of effluent spreads several kilometers around the distillery. The untreated= partially treated effluent if discharged in the land makes it infertile. Environmental issues have become one of the important factors controlling the growth of distillery industries. Therefore, it is very necessary to investigate the efficient and cost-effective processes to treat SW. The physicochemical processes are still not being applied in many distilleries, which are possible to have feasible remediation technologies to combat environmental pollution. In the present review article, different physicochemical technologies like coagulation, flocculation, electrocoagulation, thermolysis, wet oxidation, and adsorption as well as biological treatment for the wastewater of distillery industries have been presented. The distillery wastewater management is also discussed.