Distilleries can be categorized as highly polluting industries generating large volumes of wastewater known as spent wash. Elimination of pollutants and colour from distillery effluent is becoming increasingly important, as such effluent leads to extensive soil and water pollution due to its high BOD and COD content and the presence of toxic materials such as phenolic compounds.
Distillery wastewater can also have a very low pH. Distilleries generate wastewater at various stages in the process, such as distillation, condenser cooling, fermenter cooling, fermentation and washing stages. The most significant amounts of this effluent is produced at distillation and condenser cooling stages. The characteristics of the wastewater generated depend on the feed stock used.
Distilleries are agro-based industries, which utilize agricultural products such as sugar cane juice, sugar cane molasses, sugar beet molasses, corn, wheat, cassava, rice, barley as raw materials due to the big volume of effluent and presence of certain recalcitrant compounds, the treatment of this stream is rather challenging by conventional methods.