CN110980885A

CN110980885A - Method for efficiently treating and recycling sewage in printing and dyeing industry

Info

Publication number: CN110980885A
Application number: CN201911344438.0A
Authority: CN
Inventors: 王春浩; 胡晓宇
Original assignee: Tianjin Motimo Membrane Technology Co Ltd
Current assignee: Tianjin Motimo Membrane Technology Co Ltd
Priority date: 2019-12-23
Filing date: 2019-12-23
Publication date: 2020-04-10

Abstract

The invention discloses a method for efficiently treating and recycling sewage in the printing and dyeing industry. The invention adopts the hollow fiber decolorizing membrane to treat the wastewater discharged from the two reservoirs and treated by anaerobic microorganisms, the recovery rate is 50 percent, the pressure is 0.1 MPa, the temperature is 34 ℃, and the pH is = 6.7; the produced water is recycled, and the concentrated water is oxidized by using sodium hypochlorite and then is discharged after reaching the standard. The invention greatly shortens the flow, and greatly reduces the investment cost and the operation cost. The invention can remove the dirt with pertinence and has low energy consumption.

Description

Method for efficiently treating and recycling sewage in printing and dyeing industry

Technical Field

The invention relates to the field of industrial wastewater treatment, in particular to a method for efficiently treating and recycling sewage in the printing and dyeing industry.

Background

The common method for treating industrial wastewater (especially printing and dyeing wastewater) in the market at present mainly adopts biochemical degradation to remove pollutants, and then uses reverse osmosis to produce recyclable reclaimed water. The specific process is as follows: and the sewage enters a Membrane Bioreactor (MBR) from the regulating tank (or the flocculated secondary sedimentation tank). Indexes such as COD (chemical oxygen demand) and the like of MBR produced water reach the emission standard, but the printing and dyeing industry is difficult to completely remove a large amount of dyes, particularly reactive dyes commonly used in recent years. Therefore, after the pretreatment of ultrafiltration, the dye is completely removed by a reverse osmosis system, and most of salt in the sewage, such as sodium sulfate, sodium chloride and the like, is removed. The reverse osmosis water can reach the standard and be discharged or recycled.

In the prior art, no special pertinence is provided for pollutant treatment, and only various methods are comprehensively adopted to continuously reduce the pollutant content. In particular, dye pollutants are reduced after each stage of sewage treatment process, but cannot be completely removed until passing through a final reverse osmosis system, which is caused by the fact that the existing treatment method is not targeted. The reverse osmosis system also retains most of the salt while removing the dye, and most of the salt is recyclable in the printing and dyeing industry, such as sodium sulfate (the main component of mirabilite). The existing method has long process, consumes time and energy.

Disclosure of Invention

The invention aims to solve the technical problem of overcoming the defects in the prior art and provides a method for efficiently treating and recycling sewage in the printing and dyeing industry.

The invention relates to a method for efficiently treating and recycling sewage in printing and dyeing industry, which is realized by adopting the following technical scheme that waste water discharged from two water reservoirs and treated by anaerobic microorganisms is treated by adopting a hollow fiber decolorizing membrane, wherein the recovery rate is 50%, the pressure is 0.1 MPa, the temperature is 34 ℃, and the pH is = 6.7; the produced water is recycled, and the concentrated water is oxidized by using sodium hypochlorite and then is discharged after reaching the standard. Other membrane materials such as a Membrane Bioreactor (MBR), ultrafiltration, reverse osmosis and the like are not used any more, and the 'short-flow' sewage treatment and recovery process is realized.

The invention adopts the hollow fiber decolorizing membrane, which can purposefully remove dye pollutants in the sewage, and particularly can intercept reactive dye which is particularly difficult to treat but widely used. Thus, the dye can be removed before entering the MBR system, and the load of the sewage treatment system is reduced. And the produced water can be directly recycled under certain conditions, so that the sewage treatment process is greatly shortened, the 'short-process' process is realized, the salt is recycled, and the wastewater is recycled to the maximum extent.

Compared with the prior art, the invention has the beneficial effects that:

1. the invention greatly shortens the flow, and greatly reduces the investment cost and the operation cost.

2. The invention can remove the dirt with pertinence and has low energy consumption.

3. The invention recycles salt and improves the recycling degree of the waste water.

Detailed Description

The present invention will be described in further detail with reference to specific examples. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

Comparative example 1

Some printing and dyeing enterprises use reactive dyes to produce high-grade cloth, which is mainly black/red and blue. The sewage in the factory is treated by using the traditional process, and the daily treatment capacity is 2000 tons. The sewage is treated by adopting a two-section anaerobic and aerobic Membrane Bioreactor (MBR) process, 50 percent of sewage is recycled by using an ultrafiltration and reverse osmosis process, and the residual sewage is decolorized by adding sodium hypochlorite/COD is reduced and then is discharged after reaching the standard. By using the method, 50% of wastewater can be recovered, the salt in the wastewater cannot be recycled, and specific indexes are summarized in table 1.

Example 1

The hollow fiber decolorization membrane is used for treating wastewater by using anaerobic microorganisms, and the recovery rate of effluent from two water reservoirs is 50%, the pressure is 0.1 MPa, the temperature is 34 ℃, and the pH is = 6.7. The produced water is recycled, and the concentrated water is oxidized by using sodium hypochlorite and then is discharged after reaching the standard. Other membrane materials such as a Membrane Bioreactor (MBR), ultrafiltration, reverse osmosis and the like are not used any more, and the 'short-flow' sewage treatment and recovery process is realized. The indices are summarized in Table 1.

Example 2

The same procedure as in example 1 was repeated except that MBR produced water was treated with a hollow fiber decolorizing membrane without using ultrafiltration or reverse osmosis membrane for water recovery.

Example 3

The hollow fiber decolorizing membrane is used for treating reverse osmosis concentrated water, 50% is recovered from the concentrated water, and the decolorization membrane concentrated water is oxidized by sodium hypochlorite and then discharged after reaching the standard. The total wastewater discharge amount is reduced to 25 percent, and the purpose of wastewater decrement discharge is realized.

Watch (A)

Different pollutantsComparison of Water treatment Processes

	Energy consumption, kW.h/ton	Running cost, yuan/ton	Amount of salt recovered%
				Comparative example	2.7	2.6	0
Example 1	0.41	0.35	50
				Example 2	0.78	0.83	50
Example 3	1.95	1.94	25

From the above table, it can be seen that, after the hollow fiber decolorizing membrane is adopted, the energy consumption and the cost for recovering each ton of water are greatly reduced no matter which process is adopted, and simultaneously the salt content in the water can be recovered. In particular, the more advanced the hollow fiber decolorizing membrane is used, i.e., the shorter the flow path, the more membranes are replaced, and the more significant the cost reduction.

The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.

Claims

1. A method for the efficient treatment and reuse of sewage in the printing and dyeing industry is characterized in that a hollow fiber decolorizing membrane is adopted to treat the wastewater discharged from two water reservoirs and treated by anaerobic microorganisms, the recovery rate is 50%, the pressure is 0.1 MPa, the temperature is 34 ℃, and the pH is = 6.7; the produced water is recycled, and the concentrated water is oxidized by using sodium hypochlorite and then is discharged after reaching the standard.