Cold rolled steel coil wastewater treatment method

Abstract

The invention discloses a cold rolled steel coil wastewater treatment method. The method comprises the following known steps: adding hydrated lime to neutralize, adjusting the pH value and then adding a coagulant to stir and perform flocculation precipitation. The method also comprises the step of adding a nutrient solution in the wastewater of an anoxic denitrification tank, wherein anaerobic microorganisms use the nitrogen source in the wastewater to perform a metabolic reaction and reduce nitrogen nitrate to nitrogen for emission, thus the denitrification aim can be achieved; and after the step, the wastewater enters an aeration tank to remove the residual organic matter and nitrify ammonia nitrogen in the water. By adopting the method, the content of nitrogen nitrate in the discharged wastewater can be greatly reduced, the discharged wastewater can meet the national sewage discharge standard and the method is environmentally-friendly.

Description

technical field [0001] The invention belongs to the field of waste water treatment, and in particular relates to a cold-rolled steel coil waste water treatment method. Background technique [0002] In the production process of cold-rolled stainless steel, it needs to go through processes such as annealing, pickling, cold rolling, grinding, polishing, leveling, cutting, etc., which will generate a lot of waste water, including: acid waste water discharged from the pickling line; steel surface Wastewater containing salt and metal ions discharged after activation treatment or passivation; in order to eliminate thermal deformation caused by cold rolling in the strip rolling process, an emulsion (mainly composed of 2 to 10% mineral oil Or vegetable oil, anionic or non-ionic emulsifier and water) for cooling and lubrication, resulting in cold rolling emulsion wastewater; cooling strip steel must be degreased with alkaline solution before unwinding and annealing to generate alkali ...

AI Technical Summary

Problems solved by technology

If discharged directly, it will cause great pollution to the environment

[0003] In order to avoid polluting the environment, the currently used wastewater treatment process steps are: first neutralize the acidic wastewater and alkaline wastewater in the neutralization tank, and add slaked lime to adjust the pH value to 7.0-9.5. At this time, the metal ions in the wastewater Precipitation particles are formed, and at the same time, F reacts with lime to generate CaF 2 Precipitation: Neutralize the sedimentation wastewater into the coagulation tank, add coagulant polyacrylamide (PAM) to stir and flocculate, improve the sedimentation performance of the sediment particles, and after sedimentation in the coagulation tank, it will go to the intermediate pool, where the nitrate nitrogen (concentration 5000mg / L or above) cannot be removed, direct discharge will still cause environmental pollution and damage

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