Studies on biomethanation of distillery wastes and its mathematical analysis

Distillery wastes from alcohol manufacturing units such as breweries etc. are highly polluted with organic substances. It is necessary to decrease the pollution load to have eco-friendly environment and simultaneously to recover energy from the distillery slop which possesses enormous energy potential. In view of these experimental studies on biomethanation of distillery wastes have been carried out in a semi-batch digester having different BOD loading of 1.54, 2.12, 2.74, 3.28 and 4.45 kg/Cu m at different digestion temperatures in the range of 35-55 degreesC for hydraulic retention time of 14 days under controlled pH in the range of 6.8-7.2. Generated biogas has been collected at different retention days, and analysis of the gas has been made accordingly. It has been observed that biogas yield as well as methane yield have increased gradually giving maximum yield on 7th day after which biogas generation has gradually decreased., The present study deals with the mathematical analysis of the experimental data on biomethanation and suggests model equations relating maximum specific growth rate and kinetic parameter with digestion temperatures and BOD loading. (C) 2004 Elsevier B.V. All rights reserved.