The mechanism of synergistic effect between iron-carbon microelectrolysis and biodegradation for strengthening phenols removal in coal gasification wastewater treatment

[Display omitted] •The synergistic effect between microelectrolysis and biodegradation was explored.•The growth of electro-active bacteria was induced by microelectrolysis reaction.•The syntrophy between phenols-degrading bacteria and electro-active bacteria.•Electro-active bacteria promoted electrochemical efficiency of ICME process.•The integrated ICME-AS process effectively strengthened phenolic degradation. A novel iron-carbon microelectrolysis (ICME) inoculated with activated sludge (AS) process was specifically designed to look into the roles of microelectrolysis and biodegradation as well as their synergistic effect on phenols removal in coal gasification wastewater (CGW) treatment. The results indicated that the removal efficiency of COD, phenols and TOC in integrated ICME-AS process reached 87.36 ± 2.98%, 92.62 ± 0.76% and 84.45 ± 0.65%, respectively. Moreover, phenols-degrading bacteria and electrochemical-active bacteria presented better adaptability to phenolic impact. Meanwhile their syntrophic interaction was driven under the simulation of microelectrolysis. Furthermore, electrochemical redox efficiency was significantly improved, and the corresponding maximum power output reached 0.043 ± 0.01 mW/cm2. Apparently, the synergistic effect between microelectrolysis and biological action effectively strengthened phenols degradation and electricity generation. The results proved that the integrated ICME-AS process was a promising technology applied for CGW and other refractory industrial wastewater treatments.