A state-of-the-art review on nitrous oxide control from waste treatment and industrial sources

This review aims at holistically analyzing the environmental problems associated with nitrous oxide (N₂O) emissions by evaluating the most important sources of N₂O and its environmental impacts. Emissions from wastewater treatment processes and the industrial production of nitric and adipic acid represent nowadays the most important anthropogenic point sources of N₂O. Therefore, state-of-the-art strategies to mitigate the generation and release to the atmosphere of this greenhouse and O₃-depleting gas in the waste treatment and industrial sectors are also reviewed. An updated review of the end-of-the-pipe technologies for N₂O abatement, both in the waste treatment and industrial sectors, is herein presented and critically discussed for the first time. Despite the consistent efforts recently conducted in the development of cost-efficient and eco-friendly N₂O abatement technologies, physical/chemical technologies still constitute the most popular treatments for the control of industrial N₂O emissions at commercial scale. The recent advances achieved on biological N₂O abatement based on heterotrophic denitrification have opened new opportunities for the development of eco-friendly alternatives for the treatment of N₂O emissions. Finally, the main limitations and challenges faced by these novel N₂O abatement biotechnologies are identified in order to pave the way for market implementation.