Decolourisation Of Biomethanated Distillery Spent Wash Using Modified Soil

Abstract

During ethanol fermentation from molasses, spent wash is released which mainly newlineconsists of melanoidins that contribute to its color. Melanoidin are recalcitrant newlinepollutant that disturbes the land and water ecosystem. Treatment of biomethanated newlinedistillery spent wash through conventional approach is incapable of bringing its newlinecharacteristics to the level set by central pollution control board and advance newlinetechnologies are unaffordable. None of the current technologies provides a fail-safe newlinesolution. As a result, we propose a novel approach for decolourising biomethanated newlinedistillery spent wash with a reasonable return on investment. Initial observations on newlinechemical oxygen demand of biomethanated distillery spent wash were 22,000-26000 newlinemg/l. It was characterised as a rich source of nutrients like Nitrogen, Potassium, newlinePhosphorus, Calcium, Magnesium, Sulphur, Iron, Manganese, Zinc and Copper. It newlinealso had a dark black brown colour due to melanoidin, and a pH in between 3.5-4.0. newlineTotal solids, total dissolved solids and total suspended solids were found to be 89.5 newlinemg/l, 67.05 mg/l and 36.42 mg/l respectively. Specific gravity of biomethanated newlinedistillery spent wash was 1.022 and Fourier-transform infrared spectroscopy shows newlinethe presence of chromogenic groups. To decolourise biomethanated distillery spent newlinewash, a biochemical treatment approach was designed. Our methodology involves newlineinitial batch studies of decolourisation using individual adsorbent, followed by newlinecontinuous column decolourisation using modified soil made by mixing the newlineadsorbents. Black cotton soil, sand particles, distillery yeast sludge, and sugarcane newlinebagasse were selected for the study, and each adsorbent under static batch mode newlineshowed a maximum decolourisation of 73.33%, 66.086%, 62.958% and 59.646% newlinerespectively. A melanoidin degrading mixed microbial consortium was raised from newlinesoil using minimal media, which could decolourise biomethanated distillery spent newlinewash up to the tune of 82.36% and 80 % under agitation-batch mode (24 hours) and newline