A system for integrated treatment of membrane industry wastewater

Abstract

The utility model discloses a kind of system for treating membrane industrial wastewater comprehensively, belong to membrane industrial wastewater treatment field, containing rectification module and biochemical treatment module, the rectification module contains thin film evaporator, rectification tower, water-steam heat exchanger, for the recycling of DMAc;The biochemical treatment module contains grid pool, adjustment acidification pool, anaerobic tower, anoxic pool, aerobic pool, MBR pool, for processing concentrated solution containing small amount DMAc and large amount PVP;The utility model realizes the efficient separation and recycling of high concentration membrane industrial wastewater DMAc, by multistage biochemical action, realizes the efficient degradation of small amount DMAc and large amount PVP in concentrated solution and the harmless treatment of nitrogen, the utility model high processing efficiency, equipment operation is stable, environment friendly, can realize the zero emission of membrane industrial wastewater.

Description

Technical Field

[0001] This utility model relates to the field of membrane industry wastewater treatment, specifically to a system for the comprehensive treatment of membrane industry wastewater. Background Technology

[0002] N,N-Dimethylacetamide (DMAc) is widely used as a common organic solvent in industries such as membrane manufacturing, pharmaceuticals, pesticides, dyes, and electronics. This results in wastewater containing high concentrations of DMAc. If this wastewater is discharged directly without treatment, it will cause serious environmental pollution and ecological damage, and will also have adverse effects on human health. Since DMAc is a bacteriostatic agent, it will kill the bacteria in activated sludge used in wastewater treatment processes at high concentrations. Therefore, it is difficult to treat wastewater containing high concentrations of DMAc using ordinary biological treatment methods alone.

[0003] Currently, common methods for treating high-concentration DMAc wastewater mainly include physical adsorption, chemical oxidation, and biological treatment. However, these methods have many shortcomings: physical adsorption methods, such as using activated carbon, can remove some DMAc, but the adsorption capacity is limited and cannot completely degrade DMAc; chemical oxidation methods, although having high degradation efficiency, are expensive and may cause secondary pollution; traditional biological treatment methods have limited effectiveness in treating DMAc, mainly because DMAc has a strong bioinhibitory effect, affecting the normal metabolism of microorganisms.

[0004] Wastewater from the membrane industry contains difficult-to-treat substances such as DMAc and PVP. Current common treatment methods involve adding high concentrations of inorganic acids to acidify and hydrolyze the wastewater, followed by adding large amounts of alkali to neutralize the pH. However, many of these high-concentration inorganic acids are hazardous chemicals that can be used to manufacture toxic or explosive substances. This approach not only wastes a significant amount of acid-base additives but also results in the loss of DMAc, a crucial raw material in the chemical industry, making it neither economical nor environmentally friendly. Therefore, how to recycle and treat high-concentration DMAc wastewater to meet discharge standards has become an urgent problem to be solved.

[0005] Technical problem: The technical problem to be solved by this utility model is to provide a system for the comprehensive treatment of membrane industry wastewater, which solves the problems of low wastewater treatment efficiency, serious waste of acid and alkali and poor safety in the existing technology for treating membrane industry wastewater.

[0006] Technical Solution: To solve the above-mentioned technical problems, the technical solution adopted by this utility model is as follows: A system for comprehensively treating membrane industry wastewater, comprising a distillation module and a biochemical treatment module. The distillation module includes a thin-film evaporator, a distillation column, and a steam-water heat exchanger. The upper end of the thin-film evaporator is connected to the distillation column via a pipe, and the upper part of the distillation column is connected to the inlet of the steam-water heat exchanger via a pipe. The outlet of the steam-water heat exchanger is connected to the distillation column at one end via a pipe and a variable frequency gear pump at the other end via a grid tank. The top product of the distillation column is liquefied, and part of it is returned to the distillation column, while the other part flows into the grid tank to dilute the concentrated liquid of the thin-film evaporator (wastewater containing PVP and a small amount of DMAc). The membrane industry wastewater enters the thin-film evaporator for preliminary separation, and the vaporized mixture of DMAc and water enters the distillation column for binary separation.

[0007] The biochemical treatment module includes a bar screen, an acidification and equalization tank, an anaerobic tower, an anoxic tank, an aerobic tank, and an MBR tank. The devices are connected in series via pipelines. The outlet of the concentrated liquid from the thin-film evaporator is connected to the bar screen via a pipeline. The concentrated liquid from the outlet of the thin-film evaporator enters the subsequent biochemical treatment module. In the bar screen, larger solid impurities are removed by bar filtration. The wastewater treated in the bar screen is transported to the acidification and equalization tank via pipeline for water quality and quantity adjustment and acidification treatment. Then, it undergoes anaerobic-anoxic-aerobic treatment, which can biochemically degrade and denitrify residual DMAc and PVP. Finally, it is discharged after MBR ultrafiltration to meet the standards.

[0008] In one embodiment, the outlet of the steam-water heat exchanger is provided with a buffer tank for buffering the liquid discharged from the steam-water heat exchanger.

[0009] In one embodiment, the thin-film evaporator is a scraped-film evaporator.

[0010] In one embodiment, the MBR tank permeate pipe is connected to the grid tank for diluting the thin-film evaporator concentrate.

[0011] In one embodiment, the anaerobic tower is a UASB anaerobic bioreactor.

[0012] In one embodiment, the MBR tank is equipped with a sludge return pump to return the sludge to the anoxic tank for denitrification, further converting nitrite and nitrate into gaseous nitrogen and nitrogen oxides for discharge.

[0013] Beneficial effects: Compared with the prior art, the technical solution of this utility model has the following beneficial effects:

[0014] This invention employs a multi-stage treatment process, including a thin-film evaporator and a distillation column, to achieve efficient separation and recycling of high-concentration DMAc wastewater. This avoids the problems of limited physical adsorption capacity, high cost of chemical oxidation, and poor biological treatment effect in traditional treatment methods, thus significantly improving treatment efficiency.

[0015] This invention achieves efficient separation of DMAc and water through binary separation technology in a distillation column, avoiding the waste of acid and alkali caused by acid degradation pretreatment in existing technologies, effectively reducing processing costs, and reducing the use of easily manufactured toxic and explosive hazardous chemicals, thereby improving process safety.

[0016] This invention employs a combined treatment system of UASB anaerobic bioreactor-anoxic tank-aerobic tank, which achieves efficient degradation of DMAc and harmless treatment of nitrogen through multi-stage microbial action, overcoming the shortcomings of traditional biological treatment methods in treating DMAc with limited effectiveness.

[0017] This invention utilizes an MBR (Mechanical, Bioreactor) tank for advanced treatment, achieving efficient water purification and recycling through membrane fiber suction. Combined with a sludge return system, it forms a complete recycling system, minimizing water waste.

[0018] This invention achieves zero discharge of DMAc wastewater. Through multi-stage treatment and recycling, it ensures water quality stability and environmental protection in industrial production processes, effectively prevents environmental pollution and ecological damage, and meets the requirements of green environmental protection. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of a system for comprehensively treating membrane industry wastewater in one embodiment of this utility model.

[0020] The diagram shows: 1. Thin-film evaporator; 2. Distillation column; 3. Steam-water heat exchanger; 4. Grille tank; 5. Equalization and acidification tank; 6. Anaerobic tower; 7. Anoxic tank; 8. Aerobic tank; 9. MBR tank; 10. Buffer tank. Utility Model Content Detailed Implementation

[0021] The technical solution of this utility model will now be described in detail with reference to the accompanying drawings.

[0022] like Figure 1As shown, a comprehensive system for treating membrane industry wastewater includes a distillation module and a biochemical treatment module. The distillation module includes a thin-film evaporator 1, a distillation column 2, and a steam-water heat exchanger 3. The upper end of the thin-film evaporator 1 is connected to the distillation column 2 via a pipe. The upper part of the distillation column 2 is connected to the inlet of the steam-water heat exchanger 3 via a pipe. The outlet of the steam-water heat exchanger 3 is connected to the distillation column via a pipe, allowing a portion of the liquid condensed from the steam-water separator to be returned to the distillation column and discharged through another pipe. Excess liquid is discharged or recycled. The return flow and discharge volume are controlled by a variable frequency gear pump and a three-way valve. In one embodiment, the drain outlet of the steam-water heat exchanger 3 is connected to a grit chamber 4 via a pipe for diluting the concentrate from the thin-film evaporator 1. The concentrate contains a large amount of PVP and a small amount of DMAc wastewater. The membrane industry wastewater enters the thin-film evaporator 1 for preliminary separation. The vaporized mixture of DMAc and water enters the distillation column 2 for binary separation. The concentrate from the evaporator 1 enters the biochemical treatment module for further treatment.

[0023] The biochemical treatment module includes a screen tank 4, an acidification tank 5, an anaerobic tower 6, an anoxic tank 7, an aerobic tank 8, and an MBR tank 9. The screen tank 4, acidification tank 5, anaerobic tower 6, anoxic tank 7, aerobic tank 8, and MBR tank 9 are connected in series via pipelines. The concentrated liquid outlet of the thin-film evaporator 1 is connected to the screen tank 4 via a pipeline. The concentrated liquid from the outlet of the thin-film evaporator 1 enters the subsequent biochemical treatment module. In the screen tank 4, larger solid impurities are removed by screen filtration. The wastewater treated in the screen tank 4 is transported to the acidification tank 5 via pipeline for water quality and quantity adjustment and acidification treatment. After anaerobic-anoxic-aerobic treatment, it can biochemically degrade residual DMAc and PVP, COD and denitrify, and finally discharge after MBR ultrafiltration to meet the standards.

[0024] In one embodiment, the thin-film evaporator 1 is a scraped-film evaporator, which uses high-speed rotation to distribute the membrane industrial wastewater into a uniform thin film for evaporation. The main components of the membrane industrial wastewater, DMAc and water, are completely vaporized after passing through the thin-film evaporator and enter the distillation column.

[0025] In one embodiment, the permeate pipe of the MBR tank 9 is connected to the grid tank 4 to dilute the concentrate from the thin-film evaporator, thereby saving the use of fresh water.

[0026] In one embodiment, the anaerobic tower 6 is a UASB anaerobic bioreactor, which decomposes macromolecular PVP and residual DMAc compounds into small molecule ammonia nitrogen compounds, which are further decomposed into methane, carbon dioxide and nitrogen.

[0027] In one embodiment, the outlet of the steam-water heat exchanger is provided with a buffer tank 6 to buffer the liquid discharged from the steam-water heat exchanger. When the liquid level in the buffer tank reaches a set value, it is pumped into the distillation column and the grid tank through a variable frequency gear pump.

[0028] In one embodiment, the MBR tank 9 is equipped with a sludge return pump to return the sludge to the anoxic tank for denitrification, further converting nitrite and nitrate into gaseous nitrogen and nitrogen oxides for discharge.

[0029] The foregoing has shown and described the basic principles, main features, and advantages of this utility model. Those skilled in the art should understand that this utility model is not limited to the specific embodiments described above. The specific embodiments and descriptions in the specification are merely for further illustrating the principles of this utility model. Various changes and modifications can be made to this utility model without departing from its spirit and scope, and all such changes and modifications fall within the scope of this utility model as claimed. The scope of protection of this utility model is defined by the claims and their equivalents.

Claims

1. A system for comprehensively treating membrane industry wastewater, characterized in that, The system includes a distillation module and a biochemical treatment module. The distillation module includes a thin-film evaporator (1), a distillation column (2), and a steam-water heat exchanger (3). The upper end of the thin-film evaporator (1) is connected to the distillation column (2) through a pipe. The upper part of the distillation column (2) is connected to the inlet of the steam-water heat exchanger (3) through a pipe. The outlet of the steam-water heat exchanger is connected to the distillation column (2) through a pipe and a variable frequency gear pump at one end, and to a grid tank (4) at the other end. The biochemical treatment module includes a grid tank (4), an acidification tank (5), an anaerobic column (6), an anoxic tank (7), an aerobic tank (8), and an MBR tank (9). The grid tank (4), acidification tank (5), anaerobic column (6), anoxic tank (7), aerobic tank (8), and MBR tank (9) are connected in series through pipes. The concentrated liquid outlet of the thin-film evaporator (1) is connected to the grid tank (4) through a pipe.

2. A system for comprehensively treating membrane industry wastewater according to claim 1, characterized in that, The thin-film evaporator (1) is a scraped-film evaporator.

3. A system for comprehensively treating membrane industry wastewater according to claim 1, characterized in that, The permeate pipe of the MBR tank (9) is connected to the grid tank (4) and is used to dilute the concentrate of the thin film evaporator (1).

4. A system for comprehensively treating membrane industry wastewater according to claim 1, characterized in that, The anaerobic tower (6) is a UASB anaerobic bioreactor.

5. A system for comprehensively treating membrane industry wastewater according to claim 1, characterized in that, The MBR tank (9) is equipped with a sludge return pump to return the sludge to the anoxic tank for denitrification, further converting nitrite and nitrate into gaseous nitrogen and nitrogen oxides for discharge.

6. A system for comprehensively treating membrane industry wastewater according to claim 1, characterized in that, The outlet of the steam-water heat exchanger is equipped with a buffer tank (10).

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