Bioelectrochemical treatment of oil sands process‐affected water: A comparative study

Abstract In this study, removal of dissolved organic carbon and naphthenic acids (NAs) from oil sands process‐affected water (OSPW) was evaluated in flow‐through microbial fuel cell (MFC), microbial electrolysis cell (MEC), and microbial electrosynthesis (MES) cell setups with aerated cathodic compartments. At a hydraulic retention time of 2.4 days, the MEC and MFC setups demonstrated 79% and 4.0% removal efficiency of organic materials, respectively, with corresponding degradation rates of 27.25 and 1.86 mg (L R day) −1 (R = total reactor volume). NAs removal was also significantly higher in the MEC operated at 1.4 V with 54% and 21% removal for the MEC and MFC setups, respectively. Furthermore, once the MEC applied voltage was increased to 2 V (MES mode), NAs removal was further improved, reaching 70% efficiency. Analysis of microbial community composition using 16S rRNA gene amplicon sequences indicated the presence of known electroactive species and microbial populations capable of degrading hydrocarbons and NAs.