BATCH STUDIES ON TREATMENT OF DISTILLERY WASTEWATER BY AEROMONAS FORMICANS IN FREE AND IMMOBILIZED FORM

Abstract

Distilleries are amongst one of the gross water polluting industries identified by Pollution Control Board with about 80% of raw material ending up as waste. Sugar cane molasses is generally the raw material used in the production of alcohol. As a general rule that waste has BOD in the range, of 45,000 to 60,000 mg/I and COD in the range of 1,00,000 mg/1 to 1,30,000 mg/l. According to IS: 2490 and IS: 7968, the BOD for disposal in river and land are 30 mg/1 and 100 mg/1 respectively. Several studies undertaken by investigators in this field have failed to suggest a method or combination in tackling this problem and to reduce the pollution load to desirable standards. The effluent of such treatment units have BOD, COD, S.S. far in excess of permissible standards. Caramel colour also poses a problem. The methods adopted presently include physico-chemical treatment and biological treatment, latter being more successful. In this study, an attempt has been made to treat partially treated distillery effluent by using both free and immobilized cells of "Aeromonas formicans". The optimization of various culture parameters indicate that the maximum removal of COD and colour take place at 1:4 dilution at a pH of 8.5. Optimal glucose requirement is 0.4% and the same is 120mg/100m1 and 18mg/100m1 for NH4C1 and KH,1304 respectively. Taking 80 beads/100m1 sample, and same nutrients (as supplemented in free cells) for immobilized-cell treatment. The batch studies conducted with free cells under optimum condition indicate COD and Colour removal efficiencies of 56.8% and 83.61A respectively with detention time of 96 hours. Whereas with immobilized cells, the removal efficiencies of 57.5% for COD and 55.13% for colour have been achieved in a detention time of 72 hours.