A new comprehensive treatment system and method for printing and dyeing wastewater

Abstract

The invention relates to a novel dyeing wastewater comprehensive treatment system which comprises a pretreatment unit, a sewage enrichment unit and a supercritical water oxidation unit, wherein the pretreatment unit comprises a screening device and a regulating tank; the sewage enrichment unit comprises a membrane filter system and a membrane concentration system; an inlet of the membrane filter system is connected to an outlet of the pretreatment unit; a water producing outlet of the membrane concentration system is connected with a clean water tank; a starting fuel system, a supercritical water oxidation reactor, a gas-solid separation system and a gas-liquid separation system of the supercritical water oxidation unit are sequentially connected; a sewage inlet of the supercritical water oxidation reactor is connected with a concentrated water outlet of the sewage enrichment unit; an oxygen inlet of the supercritical water oxidation reactor is connected with an oxygen supply system; and an outlet of the gas-liquid separation system is connected with the clean water tank. By combining the membrane enrichment and supercritical water oxidation, the system can perform supercritical water oxidation treatment on dyeing wastewater with wider COD (chemical oxygen demand) range, and has high removal rate for organic matters; the effluent water chroma reaches the standard; and the generated resources and energies can be directly utilized or recovered.

Description

technical field [0001] The invention belongs to the fields of sewage treatment and resource energy recycling, and relates to a novel printing and dyeing wastewater comprehensive treatment system and method. Background technique [0002] The printing and dyeing industry is a large discharge of industrial wastewater. According to incomplete statistics, the national daily discharge of printing and dyeing wastewater is 3×106~4×106m 3 . Printing and dyeing wastewater is wastewater discharged from printing and dyeing factories that mainly process cotton, hemp, chemical fibers and their blended products. Printing and dyeing wastewater has a large amount of water, 100-200 tons of water is consumed per ton of textile printing and dyeing, and 80-90% of it becomes wastewater. Wastewater contains dyes, pastes, additives, oil agents, acids and bases, fiber impurities, sand substances, inorganic salts, etc. Textile printing and dyeing wastewater has a large amount of water, high content...

AI Technical Summary

Problems solved by technology

[0003] In recent years, due to the development of chemical fiber fabrics, the rise of imitation silk and the progress of printing and dyeing finishing technology, PVA pulp, rayon alkali hydrolyzate (mainly phthalic acid substances), new additives and other difficult biodegradable organic substances A large amount of printing and dyeing wastewater enters, and its COD concentration also rises from hundreds of mg / L to 2000-3000 mg / L, so that the COD removal rate of the original printing and dyeing wastewater biological treatment system drops from 70% to about 50%, or even lower , the traditional biological treatment process has been seriously challenged; the COD removal rate of this type of printing and dyeing wastewater by traditional chemical precipitation and air flotation is only about 30%

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