Biological denitrification treatment process for stainless steel pickling wastewater

Abstract

The invention discloses a biological denitrification treatment process for stainless steel pickling wastewater which comprises domestic sewage and pretreated pickling wastewater. The process comprises the following steps: primary anoxic (A) treatment, primary aerobic (O) treatment, secondary anoxic (A) treatment, secondary aerobic (O) treatment and secondary sedimentation tank. The process comprises the following steps: step 1, a user intensively mixes domestic sewage septic tank effluent and pretreated pickling wastewater according to different classifications of wastewater to form mixed wastewater with total nitrogen of about 550-650mg / L. According to the biological denitrification treatment process for the stainless steel pickling wastewater, technological processes of primary anoxic (A) treatment, primary aerobic (O) treatment, secondary anoxic (A) treatment, secondary aerobic (O) treatment and secondary sedimentation tank are matched, a trace amount of DO and electrolyte required by metabolism of denitrifying bacteria are provided for an anoxic section, a certain dilution effect on raw wastewater is achieved, the relative concentration of local pollutants is reduced, and a more suitable biological reaction condition is provided for the denitrification reaction of the anoxic section.

Description

technical field [0001] The invention relates to the technical field of wastewater treatment, in particular to a biological denitrification treatment process for stainless steel pickling wastewater. Background technique [0002] Stainless steel pickling wastewater is a special subdivided industry wastewater. In the pickling process, sulfuric acid, hydrofluoric acid and nitric acid are mainly used to prepare mixed acid according to the process requirements, and chemical surface treatment is carried out on stainless steel workpieces. The process of surface cleaning will produce a large amount of mixed acid and heavy metal-containing wastewater. This type of wastewater has the pollution characteristics of large water volume, high acidity, high salt content, and complex composition. Although the general chemical neutralization and precipitation process can remove heavy metals and fluoride removal, but it has basically no effect on the removal of total nitrogen pollutants caused b...

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Problems solved by technology

[0003] The object of the present invention is to provide a kind of biological denitrification treatment process of stainless steel pickling wastewater, to solve the existing wastewater treatment process proposed in the above-mentioned background technology, equipment investment is large, operation economy is poor, operation stability is poor, easy to produce secondary pollution, Problems that do not meet the current stringent emission limits

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