Comparative Study of Activated Sludge Process Enhanced Pyrethrin and Permethrin Biodegradation

Bioremediation using activated sludge have been conducted to estimate the degradability of insecticidal compounds, like permethrin and pyrethrin. In this study, the biological oxygen demand (BOD) and chemical oxygen demand (COD) were determined to correlate the biodegradable nature of the compounds. The sludge and synthetic effluent collected was analysed for the biochemical characteristics. The average COD and biodegradability index (BI) of the investigated pyrethrin sample indicated that the compound was fairly biodegradable while permethrin was relatively non-biodegradable. On reaching a bacterial concentration of 5500 µg/mL, 86% and 98% of BOD and COD reduction was achieved for pyrethrin but less than 2% of BOD reduction was observed for permethrin. Assessment of BI value periodically and comparing it to the average value for a compound can aid in monitoring the presence of toxic and non-biodegradable substance.