عنوان مقاله [English]
Polychlorinated Biphenyls are xenobiotic pollutants, commonly known as PCBs. PCBs could enter the food chain of biological organisms and accumulate in their fatty tissues. Thus, before the discharge of PCBs compounds in the environment, it is necessary to focus on processes and techniques for its removal at their sources. The objective of this research was to investigate the biodegradability of PCBs compounds by Sequencing Batch Biofilm Reactors (SBBR). Acetone and acetic acid were used as solvent in two separate reactors. Organic loading rates (OLRs) were from 0.04 to 0.75 g COD/l-d (maximum concentration of PCBs =0.7 mg/L). The SBBR was operated with four phases including fill, react (aeration), settle (sedimentation/clarification), and draw( decant) during different loading rates. The efficiency of COD and PCBs removal were evaluated. Maximum removal efficiencies of COD was 85% occurred in 0.2- 0.4 g /l-d in the reactor 1(solvent acetone). Also, in reactor 2 (solvent acetic acid) maximum removal rates were recorded as% in OLR of 0.56g COD/ld. The maximum removal efficiency of PCBs was observed at 240 days after start-up of both reactors and was 99%. The results of this research showed that the concentration of priority organic pollutants can be decreased by using biological processes such as SBBR. This study can also indicated that biodegradation of high weight compounds by aerobic bioreactors is a time consuming processes.