GREASE BIODEGRADATION - IS BIOAUGMENTATION MORE EFFECTIVE THAN NATURAL-POPULATIONS FOR START-UP

Investigations were undertaken in order to compare the grease degradat ion rates for a natural population of acclimatised activated sludge mi cro-organisms with a commercial bioaugmentation product (bioadditive) under optimum conditions in laboratory-scale batch reactors. Lard was chosen as the source of grease because it contains the fatty acids mor e commonly found in urban wastewaters. During acclimatisation, the bio additive reactor achieved a slightly better chemical oxygen demand (GO D) removal efficiency than the activated sludge reactor. Therefore, un der optimum conditions, activated sludge was able to degrade grease at nearly the same rate as a bioadditive solution. Moreover, the bioaddi tive and the activated sludge reactors had very similar kinetics of CO D removal under different grease concentrations. It was concluded that the use of natural activated sludge micro-organisms was sufficient to acclimatise biological processes to removing grease. Copyright (C) 19 96 IAWQ.