Researchers in AIST, in collaboration with JFE Steel Corporation and Kurita Water Industries Ltd, developed a treatment process for ironworks wastewater containing high concentrations of nitrate by combining nitrogen gas aeration, methanol addition, and the membrane bioreactor.
Nitrate contained in wastewater can cause eutrophication of rivers, lakes, and marshes, as well as contamination of soil and groundwater, thus appropriate treatment is needed to prevent its release into the environment. This research developed a new wastewater treatment process using nitrogen gas aeration as the existing ironworks infrastructure. A demonstration test using a 4,000-L pilot was successful in efficiently treating ironworks wastewater containing more than 6,000 mg/L of nitrate. In addition, microbial analysis revealed that a denitrifying bacterium was involved in the effective nitrate removal. This new process is expected to be used in various industrial sectors where the treatment of wastewater with high nitrate concentrations is a problem.
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