Removals of non-analogous OTC and BaP in AMCBR with and without primary substrate

Abstract

ABSTRACTAnaerobic biodegradation of mixed non-analogous two substrates was studied in a binary system with and without the primary substrate using an anaerobic multichamber bed (AMCBR). In the binary mixture, the biodegradation of less-degradable oxytetracycline (OTC) was restarted in the presence of more degradable benzo[a]pyrene (BaP) in the initial runs of the AMCBR, but enhanced biodegradation of the more recalcitrant OTC occurs in the later runs of the AMCBR due to enhanced biomass growth on dual substrates without the primary carbon source. The biodegradation yields of the OTC, BaP were discussed with sole-substrate systems and with the dual substrate system in the presence of the primary substrate. The maximum OTC and BaP yields were 93% in Run 3 with the primary substrate, while the maximum BaP and OTC yields were 95%, 98% in Run 3 without the primary substrate. A dual form of the Monod was found to adequately predict the substrate interactions in the binary mixture of OTC and BaP using only the parameters derived from batch experiments. At low BaP (4 mg L−1) and OTC (40 mg L−1) concentrations, a non-competitive inhibition does not affect the binding of the substrate and so the Ks were was not affected while the µmax was lowered. At high BaP (10 mg L−1) and OTC (100 mg L−1) concentrations, the BaP and OTC were biodegraded according to competitive inhibition with increased Ks while µmax was not affected. BaP and OTC were biodegraded according to Haldane at high concentrations (>10 mg L−1 for BaP, 100 mg L−1 OTC) where they were used as the sole substrate.