Aniline Degradation Coupled with Removal and Recovery of the Chemically Bound Nitrogen in a Bioelectrochemical System with a Micro-oxygen Bioanode

Eliminating the environmental impact of aromatic amines in traditional wastewater treatment processes requires more than one unit to allow both removal of organic components and the chemically bound nitrogen (CBN). Herein, we report, for the first time, that a bioelectrochemical system with a micro-oxygen bioanode can be a one-stage process to realize the co-removal of organic carbon and CBN derived from aniline (a mode aromatic amine) as well as recover the CBN as value-added ammonium salt. The micro-oxygen condition in the bioanode chamber was demonstrated to promote current output with aniline as the sole electron donor (0.95 ± 0.07 mA, which was 6.78 times higher compared to the anaerobic condition). Accompanied by the 91.92% degradation of aniline, 75.24% of total nitrogen was found to be simultaneously removed. Thereinto, the 54.87% removal was the fact that the produced ammonium was migrated to the cathode chamber and finally recovered by stripping into a sulfuric acid absorber, while the remaining 20.37% removal was a result of denitrification in the anode chamber. Electron balance analysis revealed that 2.14% and 3.92% of the released electrons during aniline degradation contributed to the ammonium recovery and denitrification, respectively. This study opens an opportunity to treat aromatic amine-bearing wastewater in a more compact and sustainable manner.