Bioelectrochemical anaerobic oxidation of ammonia for sustainable N removal from wastewater

ended

In the last decade, the field of microbial electro catalysis has given birth to a wide variety of microbial electrochemical technologies (MET). MET use the extraordinary ability of some microorganisms to transfer electrons from a substrate in wastewater to a solid-state anode, which allows for different applications e.g., production of H2 , CH4, or electricity, desalination or simply wastewater treatment. Recently, electroactive microorganisms were integrated in constructed wetlands (CW) for the treatment of municipal and industrial wastewater in a new technology called METland®. METlands allow for intensification of (previously considered extensive) CW for decentralized wastewater treatment. Although METlands perform 10-times better than conventional CW in terms of removal of organic C, about 50% of the NH4+ in the wastewater remains untouched and is discharged to surface waters contributing to N pollution and high risk of eutrophication. The majority of studies about MET focus on heterotrophic microorganisms but few works have studied anaerobic NH4+ oxidizing-, anode respiring microorganisms. The feammox reaction (anaerobic oxidation of ammonium using insoluble Fe3+ as electron acceptor) has been shown in natural environments but has yet not been exploited for wastewater treatment. Integration of feammox in wastewater treatment by replacing the iron by an anode will enable anaerobic nitrification, minimizing the most problematic issue for treating wastewater in thousands of European small populations: the costs derived from energy-intensive aeration for conventional nitrification. In ELECTRAMMOX we will enrich and characterize anaerobic ammonia-oxidizing, anode-respiring microorganisms (electrammox bacteria) and integrate them in METlands for N removal from sewage. The project outlines a research trajectory that includes fundamental investigation of the metabolism of electrammox bacteria and their application for wastewater treatment at a pilot scale.