Effective Utilization and Conversion of Spent Distillery Liquid to Valuable Products Using an Intensified Technology of Two-stage Biological Sequestration

R. Ravikumar and V. Karthik

Abstract
The potential of Cladosporium cladosporioides and Phormidium valdernium in treating spent distillery liquid in a two-stage sequential step was investigated. During the batch experiment, a maximum decolourisation of 68.5 % and 81.37 % COD reduction was achieved in the first-stage bioreactor. Further, the spent wash from bioreactor was treated with cyanobacteria in the second stage and resulted in COD reduction (3,652 mg L–1) of 89.5 % and 92.7 % decolorization, respectively. Biodegradation was confirmed using HPLC analysis, and the products released during the degradation in the two stages were identified using GC-MS analysis, and found to be 2-octenyl acetate, 1,6-heptadiene from the fungi and oxotetrahydrofuran, hexadecane from cyanobacteria which in turn reveals the fact that the sequential treatment was through the mechanism of biodegradation and not by adsorption. The results imply that sequential treatment using the combination of fungi and cyanobacteria resulted in better degradation and decolourisation for the distillery spent wash.

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Keywords
biodegradation, COD reduction, sequential treatment, decolourisation, distillery spent wash