CN101050016A - Method for treating dyeing wastewater in transfer piping by ozone - Google Patents

Abstract

The invention belongs to the application technical fields of environmental protection, industrial water treatment and the like, and relates to a method for treating printing and dyeing wastewater with ozone in a conveying pipeline. The present invention can complete the advanced treatment of printing and dyeing wastewater by ozone in a 3m-10m long transportation pipeline. The printing and dyeing wastewater is mixed and contacted with ozone through a jet, the mass transfer efficiency of ozone is greater than 98%, and the reaction time of printing and dyeing wastewater is 1s-5s , The decolorization rate of the effluent is over 98%, the COD removal rate is over 95%, the effluent water is of high quality, can be reused, and saves water resources. The effect and benefit of the present invention is to achieve online continuous treatment of printing and dyeing wastewater, high ozone mass transfer efficiency, high utilization rate, eliminating the need for bulky bubble towers and other devices in the traditional process, the remaining ozone is decomposed into oxygen, and there is no secondary pollution , can be widely used in the advanced treatment of industrial printing and dyeing wastewater, especially for the treatment of high-concentration printing and dyeing wastewater.

Description

A method for treating printing and dyeing wastewater with ozone in the pipeline

technical field

The invention belongs to the application technical fields of environmental protection, industrial water treatment and the like, and relates to a method for treating printing and dyeing wastewater with ozone in a conveying pipeline.

Background technique

After my country's accession to WTO, the printing and dyeing industry has experienced unprecedented rapid development, and has become the largest country in the world's printing and dyeing industry. While the printing and dyeing industry creates economic benefits for the country, it has also become a major water polluter. The printing and dyeing industry discharges more than 720 million tons of wastewater every year. Printing and dyeing wastewater has large discharge, high chroma, high COD (2000-3000mg/L), and is difficult to biochemically degrade. It is currently recognized as one of the difficult-to-treat harmful industrial wastewater. The serious pollution of Taihu Lake and Huaihe River, printing and dyeing wastewater is the culprit. Therefore, many experts actively call for curbing the "dyeing" of rivers by printing and dyeing wastewater.

Recently, the State Environmental Protection Administration and the State Economic and Trade Commission jointly issued the "Technical Policy on the Prevention and Control of Wastewater Pollution in the Printing and Dyeing Industry". It is required that by 2010, all large and medium-sized enterprises in the textile industry will implement cleaner production and cleaner production audits, which is a great technical challenge for enterprises. With the increasingly stringent production process and discharge standards and the rising water and sewage charges, the advanced treatment and recycling technology of printing and dyeing wastewater has become the focus of attention of textile printing and dyeing enterprises. But at present, the traditional biochemical plus physical chemical method cannot achieve the reuse of printing and dyeing wastewater.

As a strong oxidizing agent, ozone has been applied in water disinfection, and there are many application examples in the process of wastewater treatment. The ozone oxidation decolorization method can almost completely decolorize wastewater containing reactive dyes, cationic dyes, acid dyes, linear dyes and other water-soluble dyes. For decolorization, good decolorization effect can also be obtained for water-insoluble disperse dyes, but for water-insoluble dyes such as vulcanization, reduction, and paint, the decolorization effect is slightly worse. Ozone treatment of printing and dyeing wastewater has been applied in many countries such as the United States, Germany, the United Kingdom, France, Japan, and China. The advantages of the ozone oxidation method are that it has a strong oxidation ability and a significant effect in removing pollutants. The remaining ozone in the wastewater after treatment is easy to decompose. , no secondary pollution. Practice has proved that ozone can efficiently break the straight chain and unsaturated bonds in dye molecules, thereby decolorizing printing and dyeing wastewater, but ozone has little effect on the removal of chemical oxygen demand (COD), only when the ozone concentration reaches 50mg/L , COD, TOC can achieve a better removal effect. Ozone treatment of printing and dyeing wastewater is mainly affected by the mass transfer efficiency of ozone. Traditional ozone treatment of printing and dyeing wastewater usually uses a bubble tower to complete the transfer of ozone in gas and liquid phases. The mass transfer efficiency of ozone is low. Later, with the development of membrane technology and process However, the contact time between ozone and dye wastewater still needs 30-60 minutes, and the decolorization rate of dye can reach more than 95%. Affected by mass transfer efficiency, the biggest problem in the ozone treatment printing and dyeing wastewater system is that a large amount of foam will be generated during the treatment process, and a large amount of calcium oxalate, calcium carbonate and iron hydroxide will be generated in a short period of time. , The valve is blocked, and it is not good for the pump.

Contents of the invention

The purpose of the present invention is to solve the problem of low mass transfer efficiency in ozone treatment of printing and dyeing wastewater, and to provide a method for ozone treatment of printing and dyeing wastewater in a conveying pipeline. This method can complete the oxidation treatment in the printing and dyeing wastewater transportation pipeline. The jet device provided can improve the mass transfer efficiency of ozone, save the traditional huge bubble tower and other devices, greatly shorten the contact time between ozone and printing and dyeing wastewater, and improve the efficiency of ozone production. The utilization rate reduces the operating cost.

The technical scheme of the present invention is: the present invention uses ozone to carry out oxidation treatment of printing and dyeing wastewater in the conveying pipeline. Ozone can be in contact with printing and dyeing wastewater through an ejector. The mass transfer efficiency of ozone is greater than 98%, and the reaction time is 1s to 5s. Then, the decolorization and degradation reaction of dyes and other organic substances can be completed in the printing and dyeing wastewater transportation pipeline (the pipeline is 3m to 10m long). . Ozone is added to the unsaturated double bond of the dye molecule, and the ring is opened to generate organic acids, aldehydes, ketones, and alkanes and other intermediate organic substances with relatively small molecular weights, which are then gradually oxidized by ozone into inorganic substances, and finally generate carbon dioxide, water, and other ions; the decolorization rate of the effluent after ozonation can reach more than 98%, and the COD removal rate can reach more than 95%, which can be used as reused water. The remaining ozone is treated with the remaining ozone elimination device to generate oxygen for evacuation.

The effect and benefit of the present invention are: the present invention uses the jet device to complete the mass transfer of ozone, the mass transfer efficiency is high, and the oxidation reaction is completed in the transportation pipeline of printing and dyeing wastewater, which saves the bulky bubble tower device in the traditional process; The improvement of ozone mass transfer efficiency has greatly improved the utilization efficiency of ozone, avoiding the problems of a large number of bubbles blocking reactors, pipelines, and valves caused by poor ozone dissolution; Significantly, the remaining ozone is easy to decompose and does not produce secondary pollution; the treatment process is short, the equipment is easy to operate, and can be continuously operated for online treatment of printing and dyeing wastewater; the effluent water quality is high, and the treated printing and dyeing wastewater can be reused, saving water resources; The invention can be widely used in the treatment of printing and dyeing wastewater, and is especially suitable for treating high-concentration printing and dyeing wastewater.

Description of drawings

The accompanying drawing is a schematic diagram of the specific implementation steps of the method for ozone treatment of printing and dyeing wastewater in the delivery pipeline.

In the figure: 1 pretreated printing and dyeing wastewater, 2 control valve, 3 flow meter, 4 pump, 5 ejector, 6 ozone, 7 delivery pipeline, 8 gas-liquid separation device, 9 residual ozone elimination device, 10 water outlet.

Detailed ways

Specific embodiments of the present invention will be described in detail below in conjunction with technical solutions and accompanying drawings.

The printing and dyeing wastewater 1 after pretreatment such as sand filtration, enters the jet 5 after passing through the control valve 2, the flow meter 3 and the pump 4, and contacts with the ozone 6 in the jet 5, and the mass transfer efficiency of the ozone is greater than 98%; then printing and dyeing Wastewater and ozone complete the oxidation reaction in the pipeline 7, the reaction time is 1s~5s, and the length of the pipeline 7 is 3~10m; the ozonated printing and dyeing wastewater enters the gas-liquid separation device 8 to separate the remaining ozone, and then the ozone After entering the residual ozone elimination device through the control valve 2, it becomes oxygen and then discharged; the decolorization rate of the effluent 10 can reach more than 98%, and the COD removal rate can reach more than 95%, which can be used as reused water.

Claims (2)

1. the method for an ozonize dyeing waste water in transport pipe, it is characterized in that dyeing waste water handles in conveying pipe, dyeing waste water contacts with the ozone mixing by ejector, the mass-transfer efficiency of ozone is greater than 98%, the reaction times of dyeing waste water is 1s～5s, the percent of decolourization of water outlet reaches more than 98%, and the COD clearance reaches more than 95%.

2. according to claim 1 a kind of in transport pipe the method for ozonize dyeing waste water, it is characterized in that the organism that ozone oxidation is decomposed in the dyeing waste water carries out in transport pipe, reaction is finished in 3m～10m length pipeline.