6 - Decontamination of distillery spent wash through advanced oxidation methods

Abstract

Distillery industries play an important role in the world economy, but they also generate highly polluted wastewater, called spent wash. This spent wash contains high COD (110,000–190,000mgL−1), BOD (50,000–90,000mgL−1), and melanoidins such as nonbiodegradable coloring compounds. In the last few decades, advanced oxidation processes (AOPs) have been applied successfully to remove color and degrade pollutants from wastewater. The AOPs generate very powerful oxidants such as hydroxyl radicals, which are generated from ozone (O3), hydrogen peroxide (H2O2), photocatalysis, the Fenton process, and a combination of ultraviolet (UV) radiation. These •OH free radicals oxidize organic and inorganic compounds present in wastewater and decompose them. These methods are recognized as highly efficient for the treatment of recalcitrant water with low biodegradability and high chemical efficiency. They also have great potential to treat the highly polluted distillery spent wash. In comparison to the other treatment processes, AOPs are simple, fast, efficient, and nonselective. Thus, these methods can be applied along with other treatment processes, either in the pretreatment or the final treatment step. In this chapter, the fundamentals and applications of various AOPs relevant to the decontamination of distillery spent wash are discussed. The applications and effectiveness of various AOPs toward decolorization and COD removal from distillery spent wash are mainly discussed.