Supercritical water oxidation treatment system for printing and dyeing wastewater and sludge

Abstract

The invention discloses a supercritical water oxidation treatment system for printing and dyeing wastewater and sludge. The system comprises a concentration pretreatment device, a supercritical water oxidation device, an oxidizing agent supply device and a wastewater recycling system, wherein the concentration pretreatment device comprises a waste liquid storage tank, a nanofiltration membrane concentration module and a printing and dyeing sludge storage pool, the oxidizing agent supply device comprises a liquid oxygen storage tank, a liquid oxygen gasifier and a buffer tank, and the supercritical water oxidization device comprises an auxiliary heating supercritical water oxidization reactor, a methyl alcohol starting preheater, a methyl alcohol preheater and a waste liquid preheater. The system can be used for realizing efficient, clean and harmless treatment of high-concentration printing and dyeing wastewater and sludge at low cost.

Description

technical field [0001] The invention belongs to the fields of environmental protection and chemical industry, and relates to a supercritical water oxidation treatment system, in particular to a supercritical water oxidation treatment system for printing and dyeing wastewater and sludge. Background technique [0002] Among the four key COD emission industries in my country, the COD emission of the textile printing and dyeing industry ranks fourth, with the emission proportion rising from 6.7% in 2004 to 9.1% in 2011. In 2011, the wastewater discharge of the textile printing and dyeing industry reached 2.408 billion tons, accounting for 11.3% of the industrial wastewater discharge in this year. Printing and dyeing wastewater accounts for 80% of textile printing and dyeing industry wastewater. It is a kind of organic industrial wastewater that is difficult to treat and has become a serious environmental problem all over the world. Printing and dyeing wastewater has the charact...

AI Technical Summary

Problems solved by technology

However, the COD removal rate of coagulation treatment of printing and dyeing wastewater is only 30-60%, and a large amount of printing and dyeing sludge will be produced during the treatment process.

The chemical oxidation method is selective to the oxidation of dyes, the treatment cost is high, and the effect of degrading organic matter in wastewater is not obvious

The COD removal rate of electrolytic treatment of printing and dyeing wastewater is only 20-50%, and the consumption of electricity and electrode materials is large during the treatment process

The activated carbon adsorption method is suitable for the advanced treatment when the general biochemical and physical chemical methods are difficult to treat and reach the standard, and cannot realize the treatment of high-concentration organic wastewater

There are also deficiencies in the biological treatment of printing and dyeing wastewater. The bacteria in the biological treatment method are unstable, and the color of the wastewater is difficult to be effectively removed by biochemical methods, and it is difficult to discharge up to the standard. Subsequent treatment is required

In summary, the traditional treatment method will produce secondary pollutant printing and dyeing sludge, and every 1000 tons of printing and dyeing wastewater will produce 10-30 tons of wet sludge (water content 97%)

However, printing and dyeing sludge contains very complex components such as dyes, pastes, additives, etc. The structure of dyes has nitro and amino compounds and heavy metal elements such as copper, chromium, zinc, arsenic, etc., which has greater biological toxicity and is harmful to the environment. The pollution is very strong and it is a hazardous waste

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