Nitrogenous fuels recovery from municipal wastewater treatment plants

Abstract

Water contamination is an emerging environmental problem. Nitrogen contamination negatively affects the environment and human health; therefore, strict regulations have been made on the concentrations of nitrogen compounds in wastewater effluents by many countries. Wastewater treatment is performed by converting nitrogen molecules into nontoxic dinitrogen gas using energy and cost-intensive biological processes. During municipal wastewater treatment, nitrogen is removed to prevent the eutrophication of streams and to maintain drinking water quality. Nitrogen is a necessary nutrient, and that is why the removal of nitrogen, as well as recovery, is important from wastewater, which can be further used in fertilizers and other purposes. We provide an overview of several wastewater treatment technologies, including physical, chemical, and biological processes with biological methods, including anaerobic ammonium oxidation (anammox), bioelectrochemical systems, nitrification, denitrification, and nitrogen recovery by microalgal growth. The benefits, drawbacks, and possibilities for nitrogen recovery of various treatment approaches are also reviewed.