Influence of the addition of acetate as an external carbon and energy source in phenol conversion rate in an AnMBR under salinity and mesophilic conditions

Abstract

The toxic nature of the phenolic compounds together with high salinity contents in industrial wastewaters affect directly its treatment efficiency by biological processes. Anaerobic biodegradability of highly saline phenolic wastewater, under salinity [8 g Na+/L] and mesophilic conditions, was studied in two continuous Anaerobic Membrane BioReactor (AnMBR) systems, evaluating the influence of acetate as a co-substrate in the phenol conversion rate. Total removal of chemical oxygen demand (COD) and phenol were attained in an AnMBR with acetate as cosubstrate (4.2 g NaAc/L) at phenolic conversion rates (PhCR) as high as 0.115 g Ph/g VSS/d corresponding to influent phenol concentration of 3 g Ph/L, three times more than the maximum PhCR obtained for a control reactor fed with phenol as the sole substrate (0.042 g Ph/g VSS/d). These results demonstrate the efficiency of AnMBR technology in the degradation of highly saline phenolic wastewater and help to develop adequate strategies in order to optimize this technology to attain higher phenol conversion rates and robustness.