Sustainable nitrogen elimination biotechnologies: A review

Recently, several novel and cost-effective biological nitrogen elimination processes have been developed, including partial nitritation, nitrifier denitrification, anaerobic ammonium oxidation (Anammox), and its combined system (completely autotrophic nitrogen removal over nitrite, Canon). This paper deals with a review of novel biological nitrogen elimination technologies under anaerobic or oxygen limited conditions. The conventional nitrogen removal process (nitrification and denitrification), aerobic denitrification and other lithoautotrophic denitrification are also discussed briefly. The target of the novel process is the biological removal of nitrogen compounds from concentrated waste streams such as anaerobic digestion sludge liquor, etc. The review addresses the specifics of process, microbial diversity, performance characteristics and the future challenges for application.