Anaerobic Removal of Nitrogen: Nitrate-Dependent Methane Oxidation and Bioelectrochemical Processes

As wastewater treatment systems improve their nitrogen removal capacity, novel technological configurations are being developed to address the conformation of more efficient bioreactor configurations or to gain advantageous by-products from the nitrogen removal process. One of the new focuses for research is found for the nitrogen-dependent anaerobic ammonium oxidation metabolism. A few microorganisms can develop reduction of nitrate and/or nitrite under anaerobic conditions in the presence of organic matter. This bioprocess will surely be of importance when coupled to the anammox processes for the treatment of anaerobic digester reject water. In addition to this, bioelectrochemical processes can be used to remove nitrogen while generating electric current at the same time. These technologies could supply net energy for the operation of wastewater treatment plants and are therefore a very interesting research field in the future of water treatment both for intensive processes, such as microbial fuel cells, and for extensive processes, such as bioelectrochemical constructed wetlands.