Technological process for advanced treatment and recycle of cold rolling water

Abstract

The invention relates to an advanced treatment and recycling technique of cold rolling wastewater; wherein, a pretreatment step is carried out by combining conciliated aeration regulation, two-stage pH value regulation, dissolved air flotation and two-stage cooling. Firstly, the cold rolling wastewater enters a conciliated aeration regulation pool, water quality and water amount after conciliation are promoted to a first-stage pH valve regulation jar, then passes through a second-stage pH valve regulation jar, and the pH value of the wastewater is controlled to be between 6 and 9; the wastewater after regulation flows automatically into the dissolved air flotation, and oil contained in the wastewater and part suspended matters are removed; and dissolved air floats up from water and is subjected to two stages of cooling. A biochemical secondary treatment step adopts the technique of combing biological contact oxidation with a membrane bioreactor. An electrical adsorption desalting treatment step adopts an electrical adsorption desalting device to carry out deep desalting treatment. The technique has stable treatment effect, thus effectively removing pollutants such as the organic matters, the suspended matters, the oil and the salts, and the like contained in the cold rolling wastewater, and causing the cold rolling wastewater to be recycled so as to achieve energy saving and discharge reduction.

Description

technical field [0001] The invention belongs to the technical field of water treatment, and in particular relates to a process method for advanced treatment and reuse of cold rolling wastewater in the steel industry. Background technique [0002] The composition of cold rolling wastewater in the iron and steel industry is complex, and the water quality varies greatly. In order to effectively treat cold rolling wastewater, various chemical agents (such as HCl, Ca(OH)2, PAC, etc.) must be added in the treatment process to carry out neutralization reaction, coagulation and precipitation to remove pollutants in wastewater. In addition, the cold rolling wastewater is doped with a large amount of additives used in the strip rolling process, so that a large number of anions and cations are dissolved in the cold rolling wastewater, and the conductivity of the wastewater is relatively high, with an average conductivity greater than 3000μs / cm. After the subsequent biochemical treatme...

AI Technical Summary

Problems solved by technology

At present, the widely used desalination technologies include reverse osmosis, ion exchange, electrodialysis, distillation, etc. The biggest disadvantage of these technologies is that they have high requirements on the quality of influent water, and the quality of discharged water after conventional treatment is far from meeting the requirements of influent water.

If it is applied in the advanced treatment and reuse process of cold rolling wastewater, it will definitely increase the investment cost of pretreatment, increase the operating cost, and bring inconvenience to daily maintenance and operation.

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