Distillery spent wash: An emerging chemical pool for next generation sustainable distilleries

The ethanol distillery generates a huge quantum of undesirable dark brown coloured wastewater called “Distillery Spent Wash” (DSW) or “Vinasse” which has high COD and BOD. Presently, the disposal of DSW sustainably and efficiently is a major scientific, engineering, economic and environmental challenge in front of the distillery industry. In the present manuscript, a comprehensive approach has been made to elucidate the physicochemical properties of DSW and explored its potential for the production of commodity chemicals. The characterization of DSW samples collected from different distilleries throughout India was done by various analytical techniques such as HPLC, elemental analysis, TDS, TSS and ash content etc. Typically, the COD of DSW samples was found in the range of 1, 10,000 to 2, 05,000 ppm (parts per million) due to the variable composition of dissolved organic compounds. Of the total COD, (a) 1-2% is contributed by sugars like xylose, glucose and sucrose, (b) 30-36% by carboxylic acids like formic acid, acetic acid, propionic acid and butyric acid, (c) 5-6 % by alcohol like ethanol and (d) 50-57% by melanoidins and caramels. The estimated statistics based on the present study depicted that DSW can be a potential chemical pool for the production of commodity chemicals. Assessment of DSW for the production of commodity chemicals could appreciably contribute to both the economic and environmental aspects of distillery wastewater management. However, future distillery can be directed as a multiproduct industry for the production of commodity chemicals from distillery wastewater.