Bioremediation of Industrial Effluents: Distillery Effluent

Abstract

Distilleries are one of the most polluting industries generating enormous amount of wastewater from which an average of 10–15 L of effluent is released with the production of 1 L of alcohol. The distillery wastewater known as spent wash is characterized by its dark brown color, high temperature, low pH, and high percentage of dissolved organic and inorganic matter. It also contains nearly 2 % of the dark brown recalcitrant pigment called melanoidin which imparts dark brown color to the effluent. Various physical, chemical, and alternate treatment methods have been adopted for the removal of color from this wastewater. But these methods only change the form of contaminants rather than degrading them completely.

Biological methods produce relatively little amount of product after treatment by resolving a large amount of organism elements into carbon dioxide to be stabilized, or by removing organic matters contained in wastewater with the generation of methane gas. In the biological treatment methods, pollutants in wastewater can be resolved, detoxified, and separated by using mainly microorganisms. Due to the relatively low cost and the variations of work progress, the biological methods have been most widely used all over the world. A number of fungi, bacteria, yeast, and algae have been reported to have effluent treatment capabilities by the process of absorption, adsorption, and enzymatic degradation techniques. Toxicity studies of the biologically treated wastewaters also suggested that the process is efficient enough to reduce the toxicity of the spent wash by around 80 %. Hence, compared to the common and expensive physical or chemical ways for decolorization, an efficient bioremediation system has been found successful through biosorption and enzymatic ways of decolorization.