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.