This project aims to establish an “innovative nitrogen circular technology” to realize the detoxification and resource recovery of harmful nitrogen compounds originating from human activities. Toxic nitrogen compounds are present in exhaust gas and wastewater generated as a result of industrial and daily activities. Currently, a large amount of energy is consumed for detoxification, and in some cases, it is not sufficiently treated. In the discussion of the Planetary Boundaries, nitrogen compounds are beyond the stipulated limits far more than CO2, phosphorus, etc. Therefore, the emission of harmful nitrogen compounds is a serious environmental pollution issue. To establish a method for reducing nitrogen compound emissions without significantly reducing the amount of ammonia available for human use, we will establish a technology to convert NOx in exhaust gas and nitrogen compounds in wastewater into a form that can be used as an ammonia resource. This technology is expected to significantly improve both the environmental emissions of nitrogen compounds in exhaust gas and wastewater and the energy consumption required for treatment.
For exhaust gas, we developed a technology for the conversion of NOx to ammonia (NTA), which is a valuable resource. Achieving an ammonia conversion of 50% renders the removal of residual NOx by selective catalytic reduction stoichiometrically possible; with this approach, most NOx can be removed and surplus NH3 can be utilized for various other purposes. To recover NH4+ and organic nitrogen from wastewater, we developed an NH4+ conversion system together with an energy-saving NH4+ separation and concentration system.
Targets by 2030
FY2022: A. Test production of a gaseous NTA reactor with high efficiency. B. Construction of microbial communities for ammonia conversion from wastewater, and the design of an ammonia concentration system in aqueous phase.
FY2024: A. Basic design of the NTA system with the pilot scale. B. Bench plant test at the 0.5 m3/d scale for the recovery of ammonia resources from nitrogen compounds in wastewater.
FY2029: A. Pilot plant test for the gaseous NTA system at a scale of hundreds of Nm3/d with >95% conversion at 200 °C. B. Pilot plant test for ammonia recovery from wastewater at a scale in the range of 5–15 m3/d.
National Institute of Advanced Industrial Science and Technology (AIST), The University of Tokyo, Waseda University, Tokyo University of Agriculture and Technology, Kobe University, Osaka University, Yamaguchi University, Kyowa Hakko Bio Co. Ltd., ASTOM Corporation, Toyobo Co. Ltd., FUSO Corporation, Ube Industries, Ltd., *Tokyo Institute of Technology, *Kyoto University, *Yamagata University, *Hiroshima University (*: Subcontract)
Schematic of the nitrogen circular technology system proposed in this project.
Innovative circular technologies for harmful nitrogen compounds
Project Manager: Dr. Tohru Kawamoto, Prime Senior Researcher, National Institute of Advances Industrial Science and Technology (AIST), Japan