Phenol Degradation by Suspended Biomass in Aerobic/Anaerobic Electrochemical Reactor

The effect of direct current (DC) on phenol biodegradation under aerobic/anaerobic condition was investigated in this study using a bioelectrochemical reactor. It was found that phenol biodegradation was inhibited with current ranged from 10 to 40 mA. The growth of biomass was reduced to 43.2 +/- 6.6 % for aerobic sludge and 38.6 +/- 7.3 % for anaerobic sludge, but the loosely bound extracellular polymer substances (LB-EPS) were increased 91.2 +/- 1.3 % for aerobic sludge and 62.8 +/- 0.8 % for anaerobic sludge as the current increased from 10 to 40 mA. Adenosine triphosphate (ATP) content of aerobic sludge was also reduced 0.481 +/- 0.04-fold and 0.512 +/- 0.05-fold lower and 1.34 +/- 0.13-fold higher than that of the control when the current was increased from 10 to 40 mA. The results of phosphate buffer saline adding treatment indicated that lower pH caused by a DC above 10 mA was responsible for the reduced phenol biodegradation, leading to the reduction of biomass. However, lower intensity of current (5 mA) had no significant impact on phenol degradation rate, pH, LB-EPS, ATP content, and cell growth of aerobic/anaerobic sludge. These results give us a more detailed understanding of the effects of electricity on the treatment of phenol containing wastewater.