Biodegradation of cypermethrin by pseudomonas in a batch activated sludge process

ABSTRACT

The biodegradation of Cypermethrin [20 to 125 mg/L] in an effluent using batch activated sludge was studied. Degradation was found to occur to a great extent only in the presence of Pseudomonas [IES-Ps-1] culture. Under aerobic conditions using mechanical aerators, Cypermethrin [20 mg/L] was almost completely degraded in just over 48 h at ambient temperature. Further loading of organic compound in subsequent experiments demonstrated that IES-PS-1was capable to degrade 82% Cypermethrin at 40 mg/L dose in approximately 48 h. When the concentration was increased to 80 mg/L, 50% degradation of this compound was observed. Over this time period the cells could utilize only 17% of Cypermethrin when it was given 125 mg/L, respectively. These findings indicate that increased concentration of Cypermethrin has a marked effect on biodegradation performance of IES-Ps-1 with a modest increased in the duration of lag phase, but did not lead to complete inhibition or cell death. These results proved that IES-Ps-1 is responsible for Cypermethrin degradation. Such finding may be useful in designing a scale-up in situ or on-site hazardous waste bioremediation process for field application