Characterization of brewery waste water and evaluation of its potential for biogas production

Abstract

The issue of global warming and climate change is strongly receiving public attention and has become a major environmental concern both nationally and internationally. Brewing industries are among the largest consumers of water and the largest source of organic effluent mostly from the brewing, cleaning, and cooling processes which must be treated to allowable levels to reduce environmental pollution. Close to 10 L water is used for every 1 L beer that is brewed, though the amount of water in the final beer is small. A study was undertaken to characterize and assess the variations in the quality of untreated brewery waste water. Samples from different process streams including brewing line, clean in place line and mixing line from two brewing industries in Kenya were analyzed for BOD5, COD, TDS, TSS, sodium, total nitrogen and phosphorous using standard method as per American Public Health Association (APHA). There was a significant variation (p<0.001) in the all the physicochemical parameters between the industries and a significant interaction (p<0.001) between sampling point and the company. Analysis of the BOD to COD ratio showed the biodegradability index to range from 0.039 to 0.567 for brewing line, 0.177 to 0.766 for cleaning in place and 0.776 to 0.911 for mixing point, thus the waste water was found to be easily biodegradable at the mixing point for all the industries. However pretreatment would be required to improve anaerobic digestion.