Electrical stimulation on biodegradation of phenolics in a novel anaerobic–aerobic-coupled upflow bioelectrochemical reactor

Abstract

• An anaerobic–aerobic-coupled upflow bioelectrochemical reactor was constructed. • Intermittent electrical stimulation mode promoted phenolics degradation. • Aerobic cathodic chamber showed high contribution to the phenolics removal. • Specific microbes were enriched in the cathodic and anodic chambers of the system. Phenolics were widespread in the effluents of coal gasification plants and oil refineries processes, while the impact of electrical stimulation on phenolics degradation in the combined biological processes remained unclear. Here, a novel anaerobic–aerobic–coupled upflow bioelectrochemical reactor (AO-UBER) was used to treat phenol-containing synthetic wastewater and simulated phenolic wastewater. The AO-UBER could treat phenolic compounds effectively via electrical stimulation. Phenol and total phenol removal efficiencies in the intermittently electrically stimulated system with a hydraulic retention time of 6 h were about 22.6% and 31.1%, respectively, higher than that in the biological system not exposed to voltage. The contribution of the aerobic cathodic chamber to the removal of phenolic compounds was higher than that of the anaerobic anodic chamber under the intermittent voltage application mode. High-throughput sequencing analysis indicated that electrical stimulation selectively enriched Acinetobacter , Cloacibacterium , Acidovorax, and Zoogloea in the phenol-containing synthetic wastewater treatment process, and Rhodococcus , Achromobacter , Chryseobacterium, and PSB-M-3 in the simulated phenolic wastewater treatment process. These results demonstrate that the AO-UBER under intermittent voltage application mode holds good potential for efficient phenolic wastewater treatment.