Bioelectrochemical anoxic ammonium nitrogen removal by an MFC driven single chamber microbial electrolysis cell

• Published in: Chemosphere (Oxford) Vol. 274; p. 129715
• Main Authors: Koffi, N’Dah Joel, Okabe, Satoshi
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.07.2021
• Subjects: Ammonium Compounds; Anodic ammonium oxidation; Applied voltage; Bioelectric Energy Sources; Bioelectrochemical nitrogen removal; Bioreactors; Denitrification; Electrolysis; Microbial electrolysis cell (MEC); Microbial fuel cell (MFC); Nitrogen - analysis; Oxidation-Reduction; Waste Water; Wastewater treatment; Anodic ammonium oxidation; Microbial electrolysis cell (MEC); Wastewater treatment; Bioelectrochemical nitrogen removal; Microbial fuel cell (MFC); Applied voltage
• ISSN: 0045-6535; 1879-1298
• DOI: 10.1016/j.chemosphere.2021.129715

Nitrogen removal from wastewater is an indispensable but highly energy-demanding process, and thus more energy-saving treatment processes are required. Here, we investigated the performance of bioelectrochemical ammonium nitrogen (NH4+-N) removal from real domestic wastewater without energy-intensive aeration by a single chamber microbial electrolysis cell (MEC) that was electrically powered by a double chamber microbial fuel cell (MFC). Anoxic NH4+-N oxidation and total nitrogen (TN) removal rates were determined at various applied voltages (0–1.2 V), provided by the MFC. The MEC achieved a NH4+-N oxidation rate of 151 ± 42 g NH4+-N m−3 d−1 and TN removal rate of 95 ± 42 g-TN m−3 d−1 without aeration at the applied voltage of 0.8 V (the anode potential Eanode = +0.633 ± 0.218 V vs. SHE). These removal rates were much higher than the previously reported values and conventional biological nitrogen removal processes. Open and closed-circuit MEC batch experiments confirmed that anoxic NH4+-N oxidation was an electrochemically mediated biological process (that is, an anode acted as an electron acceptor) and denitrification occurred simultaneously without NO2− and NO3− accumulation. Moreover, ex-situ15N tracer experiment and microbial community analysis revealed that anammox and heterotrophic denitrification mainly contributed to the TN removal. Thus, the bioelectrochemical anodic NH4+-N oxidation was coupled with anammox and denitrification in this MFC-assisted MEC system. Taken together, our MFC-driven single chamber MEC could be a high rate energy-saving nitrogen removal process without external carbon and energy input and high energy-demanding aeration. [Display omitted] •An MFC driven MEC was developed for NH4+-N removal from wastewater.•This system requires no aeration, external carbon sources and power input.•Anodic NH4+ oxidation rate of 151 ± 42 g NH4+-N m−3 d−1 was achieved at Eap = 0.8 V.•Simultaneously, TN removal rate of 95 ± 42 g-TN m−3 d−1 was achieved.•This leads to development of an energy self-sustained high-rate nitrogen removal system.