Use of recirculation reactor to study biodegradation of Aroclor 1242, a polychlorinated biphenyl

The performance of immobilized microorganisms in the detoxification of hazardous waste was investigated using a recirculation flow reactor, run in a batch mode. A mixed microbial population from a wastewater treatment plant was immobilized in calcium alginate gel. The bio-oxidation ability of these microbes towards a model toxin Aroclor 1242 (R) (PCB 1242) was studied. A non-ionic surfactant (Triton X-405 (R)) was used as a medium in the enhancement of the solubility of Aroclor 1242 in aqueous phase. Dissolved oxygen concentration was monitored using a flow Clark-type dissolved oxygen probe. Oxygen consumption was compared to the biodegradation of Aroclor 1242. Physical removal of Aroclor 1242 by adhering to the system without microorganisms was also determined and was compared with the biodegradation value obtained. It was found that biodegradation was the primary removal mechanism. Total removal of Aroclor 1242 was 96, 98.6 and 98% for three consecutive spikes of which physical removal accounted for up to 25%