Combined biological treatment method for high-concentration COD chromium-containing electroplating cleaning wastewater

Abstract

The invention relates to a combined biological treatment method of high-concentration COD chromium-containing electroplating cleaning wastewater. The method comprises the following steps: sequentiallytreating the wastewater through an adjusting tank, a primary filtering unit, an oxidation unit, a biodegradation unit and a post-filtering unit, discharging after reaching the standard, and directlyrecycling or deeply treating and recycling. According to the method, a heterogeneous catalytic oxidation technology and a biotechnology are organically combined, the two treatment technologies supplement each other, and aiming at the high-concentration COD chromium-containing electroplating cleaning organic wastewater which is difficult to treat, synergistic removal of heavy metals such as high-concentration COD, low ammonia nitrogen, total phosphorus and hexavalent chromium and other various pollutants is completed. The degradation-resistant wastewater is subjected to heterogeneous catalyticoxidation regulation to create a dominant environment for subsequent biological treatment of specific strains so that hexavalent chromium detoxication and organic pollutant removal are completed at the same time. Chemical agents do not need to be added in the whole treatment process, the ion concentration in the wastewater is not increased, up-to-standard discharge or reuse as enterprise production make-up water is finally realized, and purification or resource utilization of the wastewater is realized.

Description

technical field [0001] The invention relates to the technical field of purification and treatment of industrial wastewater, in particular to a combined biological treatment method for high-concentration COD and chromium-containing electroplating cleaning wastewater. Background technique [0002] Metal chromium has the advantages of high hardness, small friction coefficient, and good chemical stability. It is widely used as protective and decorative coatings, and occupies a high proportion in the electroplating industry. The electroplating cleaning wastewater generated by the enterprise is mainly the mixed water of cleaning and degreasing wastewater, rinsing wastewater, passivation wastewater, etc. in the pretreatment process of the parts to be plated. The pollutant characteristics of this wastewater are that it contains a large amount of oil, high COD concentration, The concentration of ammonia nitrogen is low, the pH value is mostly strong alkaline, and there are many inorg...

AI Technical Summary

Problems solved by technology

Due to the high toxicity of electroplating cleaning wastewater, high COD concentration, and high refractory components, traditional biological treatment processes are almost unsuitable. At least it is necessary to consider reducing the toxicity of this type of electroplating wastewater, that is, firstly, hexavalent chromium needs to be reduced to trivalent Chromium, which in turn forms a precipitate to separate contaminants

Such treatment technologies are currently common reduction treatment technologies such as sulfite method, ferrous sulfate-lime method, and electrolytic reduction method, as well as physical and chemical treatment technologies such as electrodialysis, reverse osmosis, ion exchange, activated carbon adsorption, and flocculation. There are generally large energy and chemical consumption, high investment and operating costs, and a large amount of chromium-containing waste that needs to be treated separately, and the concentration of chromium ions in electroplating cleaning wastewater is not within the applicable concentration range of the above-mentioned treatment technologies. The technical and economic indicators will be bad

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