Pilot-scale petroleum refinery wastewaters treatment systems: Performance and microbial communities’ analysis

Abstract This study evaluated firstly the performance of the Continuous Stirred Tank bioReactor system (CSTR) for the treatment of highly toxic petroleum refinery wastewaters at the pilot-scale. The reduction of the COD, BOD5, phenols, and the total petroleum hydrocarbon (TPH) reached 82.10%, 85.87%, 91.63%, and 81.11%, respectively at high hydraulic residence time (HRT = 10 days). Decreasing HRT to 5 and 2.5 days led to a decrease in the efficiency of the process and a decrease in biomass concentration was also observed (