| 摘要 |
PROBLEM TO BE SOLVED: To provide a method and a device for treating wastewater containing nitric acid, capable of reliably improving the solid-liquid separation properties in a final sedimentation basin, and rationalizing the treatment of wastewater in a steel mill, while reducing the cost.SOLUTION: A method for treating wastewater containing nitric acid, specifically a method for treating wastewater in a steel mill, includes a denitrification step of biologically denitrifying wastewater containing nitric acid with activated sludge, an organic matter decomposition step of biologically oxidizing, decomposing and converting the organic matter (COD component) remaining without being used in the denitrification into COand water with activated sludge, and a solid-liquid separation step of separating solid-liquid in a sedimentation basin, and further an iron-containing wastewater addition step of adding wastewater containing iron generated in the steel mill in the nitrification step and/or the organic matter decomposition step. |
