Double-membrane treatment method of iron and steel industrial wastewater

Abstract

The invention provides a double-membrane treatment method of iron and steel industrial wastewater. The method comprises the following steps that the pH value of the wastewater is regulated to be greater than 7, and then, oxygen gas is introduced into the wastewater until the total iron content in the wastewater is reduced to a value smaller than 0.5mg / l; the pH value of the wastewater is regulated to 8.0 to 8.5, flocculating agents and coagulant aids are added into the wastewater under the stirring condition, and then, the static settlement is carried out; the wastewater subjected to preliminary treatment is subjected to filtering treatment in a filter so that the water outlet turbidity of the wastewater is smaller than 2NTU; the wastewater subjected to filtering treatment is subjected to full flow filtering treatment; the wastewater subjected to pretreatment is subjected to two-stage reverse osmosis treatment; and the wastewater subjected to the two-stage reverse osmosis treatment is subjected to fine treatment through a mixing bed. The double-membrane treatment method has the advantages that the treated wastewater reaches the demineralized water standard, the cyclic utilization rate of water resources is improved, the consumption of new water is saved, and the outward discharge water of a ton of steel is reduced.

Description

technical field [0001] The invention relates to a treatment method for iron and steel industry wastewater, in particular to a double-membrane treatment method for iron and steel industry wastewater by using an ultrafiltration membrane and a reverse osmosis membrane. Background technique [0002] In the past 30 years, the development of ultrafiltration technology has been extremely rapid. It not only plays a unique role in the separation of special solutions, but also has more and more applications in the reuse of industrial sewage. It is often used as pretreatment equipment to ensure subsequent Long-term safe and stable operation of equipment. [0003] Ultrafiltration is a membrane separation technology whose membrane is a porous asymmetric structure. The filtration process is a solution separation process based on the pressure difference on both sides of the membrane and based on the principle of mechanical sieving. The operating pressure is usually 0.03~0.6MPa, the sievin...

AI Technical Summary

Problems solved by technology

[0007] The technical problem to be solved by the present invention is: to overcome the defect that the existing iron and steel wastewater treatment methods cannot meet the demineralized water standard, and to provide a method for treating and recycling iron and steel production wastewater using the double-membrane water treatment technology, and the treated wastewater reaches the demineralized water standard , improve the recycling rate of water resources, save new water consumption, and reduce external drainage per ton of steel

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