Biological approaches for treatment of distillery wastewater: a review

Effluent originating from distilleries known as spent wash leads to extensive soil and water pollution. Elimination of pollutants and colour from distillery effluent is becoming increasingly important from environmental and aesthetic point of view. Stillage, fermenter and condenser cooling water and fermenter wastewater are the primary polluting streams of a typical distillery. Due to the large volumes of effluent and presence of certain recalcitrant compounds, the treatment of this stream is rather challenging by conventional methods. Therefore, to supplement the existing treatments, a number of studies encompassing physico-chemical and biological treatments have been conducted. This review presents an account of the problem and the description of colour causing components in distillery wastewater and a detailed review of existing biological approaches. Further, the studies dealing with pure cultures such as bacterial, fungal, algal and plant based systems have also been incorporated. Also, the roles of microbial enzymes in the decolourization process have been discussed to develop a better understanding of the phenomenon.