Treatment of Bio-methanated Distillery Spentwash using various Physico-Chemical Treatment Techniques

Distilleries are one of the important secondary agro based industries. Every liter of alcohol produced will generate around 8 to 10 liters of Spentwash, which is highly complex liquid waste with dark reddish brown colour. Distilleries are listed in Red category by Ministry of Environment, Forest and Climate Change, Govt. of India, due to the complexity of Spentwash. This liquid waste is very difficult to treat and safe disposal of the same is a tedious task for distilleries. Most of the distilleries have adopted anaerobic digestion as a source of energy recovery by extracting methane from spentwash. The effluent from the anaerobic digester is called Bio-methanated Spentwash (BMSW), which is partially treated, but still concentrated and the same cannot be disposed into the environment safely. Present study is a part of Research work, which concentrates on various treatment techniques to further treat the Bio-methanated Spentwash to use it in composting of Pressmud in field scale. Electrocoagulation, Adsorption and Fenton Oxidation are selected as treatment techniques for the study, to convert Bio-methanated Spentwash into Stabilized Spentwash (SSW). This study showed, Fenton oxidation has a maximum removal efficiency with COD reduction of 45%, but produces volatile organic fumes harmful for the living beings. Hence, for the field scale implementation of Stabilization of Spentwash, Electrocoagulation process is recommended, due to its efficiency and practical feasibility of implementation .