Comprehensive wastewater treatment system for spandex production

Abstract

The utility model relates to the field of wastewater treatment systems, in particular to comprehensive wastewater treatment equipment for spandex production. The utility model relates to a comprehensive wastewater treatment system for spandex production. The comprehensive wastewater treatment system comprises a concentrated water pretreatment device, a refined wastewater buffer pool, a UASB (Upflow Anaerobic Sludge Blanket) reactor, an anaerobic sedimentation tank, an anoxic tank, an aerobic tank, a rear denitrification filter tank, an MBR (Membrane Biological Reactor) tank, an MBR water producing tank, an RO (Reverse Osmosis) device and a sedimentation tank which are arranged in sequence.

Description

Technical Field

[0001] This utility model relates to the field of wastewater treatment systems, specifically to a comprehensive wastewater treatment device for spandex production. Background Technology

[0002] Spandex, short for polyurethane fiber, is a synthetic fiber renowned for its exceptional elasticity. Spandex fabrics are characterized by excellent elasticity, resistance to acids and alkalis, sweat resistance, seawater resistance, and abrasion resistance. They are widely used, primarily in various textile products that meet comfort requirements, such as casual wear, professional sportswear, and swimwear.

[0003] However, the washing, dyeing, and impregnation processes in the spandex industry, as well as the circulation and rinsing during production, generate large amounts of high-concentration wastewater. The main pollutant in the wastewater is dimethylacetamide (DMAC). DMAC, as a low-toxicity, high-boiling-point, and highly polar aprotic solvent and chemical intermediate, has wide applications in synthetic materials, pharmaceuticals, pesticides, chemical fibers, and petroleum processing. Since DMAC only acts as an organic solvent and does not undergo chemical reactions, there is almost no loss in quantity; it all enters the production wastewater. DMAC is chemically stable, with a B / C ratio of 0.065, and poor biodegradability.

[0004] Spandex wastewater is characterized by high turbidity, high COD, high BOD, and high color, seriously affecting the quality of the water environment. Therefore, the treatment of spandex wastewater is of great significance. Summary of the Invention

[0005] This utility model aims to provide a comprehensive wastewater treatment device for spandex production, the specific solution of which is as follows:

[0006] A comprehensive wastewater treatment system for spandex production includes, in sequence, a concentrated wastewater pretreatment unit, a refined wastewater buffer tank, a UASB reactor, an anaerobic sedimentation tank, an anoxic tank, an aerobic tank, a post-denitrification filter, an MBR tank, an MBR permeate tank, an RO unit, and a sedimentation tank.

[0007] The RO device is also connected to a recycled water tank.

[0008] The sedimentation tank is also connected to the AOP water treatment system.

[0009] The anaerobic sedimentation tank is also connected to a sludge tank.

[0010] The sludge tank is connected to a screw press.

[0011] This utility model has the following advantages:

[0012] 1. This utility model uses a UASB reactor, which is relatively small in volume and 3 meters taller than traditional anaerobic reactors. It occupies less space, is more energy-efficient, requires no civil engineering, and can be put into use in a short time, saving enterprise costs.

[0013] 2. Based on existing technology, this utility model provides advanced treatment for wastewater that needs to be discharged, thereby reducing the volume of discharged wastewater and pollutants, reducing the need to purchase clean water, and lowering production costs. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the structure of a comprehensive wastewater treatment system for spandex production according to this utility model.

[0015] The following are the product designations: 1. Concentrated wastewater pretreatment unit; 2. Refined wastewater buffer tank; 3. UASB reactor; 4. Anaerobic sedimentation tank; 5. Anoxic tank; 6. Aerobic tank; 7. Post-denitrification filter; 8. MBR tank; 9. MBR permeate tank; 10. RO unit; 11. Sedimentation tank; 12. Reclaimed water tank; 13. AOP water treatment system; 14. Sludge tank; 15. Screw press. Detailed Implementation

[0016] The following is combined Figure 1 Further explanation:

[0017] A comprehensive wastewater treatment system for spandex production includes, in sequence, a concentrated wastewater pretreatment unit 1, a refined wastewater buffer tank 2, a UASB reactor 3, an anaerobic sedimentation tank 4, an anoxic tank 5, an aerobic tank 6, a post-denitrification filter 7, an MBR tank 8, an MBR permeate tank 9, an RO unit 10, and a sedimentation tank 11. The RO unit 10 is also connected to a recycled water tank 12. The sedimentation tank 11 is also connected to an AOP water treatment system 13. The anaerobic sedimentation tank 4 is also connected to a sludge tank 14. The sludge tank 14 is connected to a screw press 15.

[0018] The specific application process of this wastewater treatment system is as follows:

[0019] Step 1: The spandex wastewater enters the high-concentration pretreatment reaction tank (i.e., concentrated water pretreatment device 1), and excess NaNO2 is added, followed by H2SO4. The pH of the wastewater is adjusted to 2.0-3.0, and DMAC is oxidized into N2 and discharged into the atmosphere.

[0020] Step 2: Transport the concentrated pretreatment product water obtained in Step 1 to the refined wastewater buffer tank 2 and adjust the pH of the wastewater to 6.5-8.0.

[0021] Step 3: The wastewater obtained in Step 2 is transported to the mesophilic UASB reactor 3. A heat exchanger is installed before the anaerobic reactor to ensure that the influent temperature is constant at 36°C, thereby degrading and removing organic matter from the wastewater.

[0022] Step 4: The anaerobic reactor obtained in Step 3 is transported to anaerobic sedimentation tank 4 to remove suspended solids from the wastewater.

[0023] Step 5: The precipitated water obtained in Step 4 is transported to the A / O reaction tank (anoxic tank 5 and aerobic tank 6) for biodegradation.

[0024] Step 6: The hydrolyzed acidified wastewater obtained in Step 5 is transported to the post-denitrification filter 7 to further enhance nitrogen removal.

[0025] Step 7: The effluent from the post-denitrification filter obtained in Step 6 is transported to MBR tank 8. The sludge retention capacity of the MBR is utilized to effectively remove pollutants that are difficult to biodegrade in an environment with high sludge concentration.

[0026] Step 8: The MBR permeate obtained in Step 7 (stored in MBR permeate tank 9) is transported to the RO unit 10. Utilizing the characteristics of the reverse osmosis elements, under pressure, various ions, molecules, organic matter, pyrogens, bacteria, and other contaminants in the water are removed through the membrane mass transfer process. The RO permeate is superior to the reclaimed water quality standard and is used for production reuse (reclaimed water tank 12).

[0027] Step 9: The RO concentrate enters the sedimentation tank 11 for further COD removal, and the effluent enters the AOP water treatment system 13 to oxidize most of the recalcitrant pollutants before being discharged in compliance with standards.

[0028] In the high-concentration pretreatment reaction tank (concentrated water pretreatment device 1), under acidic conditions, NaNO2 and DMAC in the wastewater undergo a redox reaction, oxidizing DMAC into N2 which is then released into the atmosphere. The treated wastewater is then discharged into the refined wastewater buffer tank 2, where the toxicity of the wastewater is reduced and its oxidizability is increased, which is beneficial for improving the effect of subsequent oxidation treatment.

[0029] The UASB reactor 3 utilizes the stepwise combined action of hydrolytic fermentation bacteria, hydrogen-producing and acetic acid-producing bacteria, and methanogenic bacteria to degrade and remove organic matter from wastewater. The UASB reactor 3 exhibits a strong mixing effect and a small water distribution area, generating and forming a granular sludge suspended bed, and preventing channeling phenomena within the anaerobic reactor. The UASB reactor 3 is relatively small in volume, only 3 meters taller than traditional anaerobic reactors, requiring less floor space and resulting in greater energy efficiency.

[0030] Anaerobic treatment has the following characteristics:

[0031] 1. Anaerobic treatment can be combined with environmental protection, energy recovery, and a virtuous cycle of ecology, resulting in good environmental and economic benefits;

[0032] 2. Anaerobic treatment is a very economical treatment technology compared to aerobic treatment, costing less than 1 / 3 of the equipment required for aerobic treatment;

[0033] 3. Energy demand is greatly reduced, to about 7.5% of the energy demand of aerobic treatment;

[0034] 4. Anaerobic treatment can also produce usable energy (methanogenesis); approximately 1.37 × 10⁻⁶ methane can be produced for every 1 kg of COD removed. 4 KJ energy;

[0035] 5. The sludge production is extremely low, only 20-180 g VSS / kg COD (removed);

[0036] 6. Anaerobic microorganisms can degrade or partially degrade some organic matter that cannot be degraded by aerobic microorganisms;

[0037] 7. The nutrient requirements for anaerobic treatment are approximately 20-30% of those for aerobic treatment;

[0038] 8. Anaerobic treatment equipment has the advantages of high processing load, small footprint, and low investment and operating costs;

[0039] 9. Anaerobic methods can treat high-concentration organic wastewater without requiring large amounts of dilution water as aerobic treatment.

[0040] 10. It is more sensitive to temperature and pH value, with an optimal temperature of around 36℃ and a pH value of 6.8-7.2;

[0041] Anaerobic treatment is usually followed immediately by aerobic enhancement treatment.

[0042] The MBR membrane bioreactor (MBR tank 8 and MBR permeate tank 9) significantly improves sludge-water separation efficiency through the highly efficient separation effect of the membrane modules. Furthermore, the increased concentration of activated sludge in the aeration tank and the presence of dominant bacteria in the sludge enhance the biochemical reaction rate. Simultaneously, this process greatly reduces the production of excess sludge, thus fundamentally solving the prominent problems of large excess sludge production, large land area requirements, and low operating efficiency inherent in traditional biological methods.

[0043] The AOP water treatment system 13 employs ozone technology, which can decolorize most organic pigments. It can slowly erode rubber and cork, oxidizing unsaturated organic compounds. Common applications include: beverage disinfection and sterilization, air purification, bleaching, water treatment, and drinking water disinfection. It reacts with unsaturated organic compounds to generate ozonides, which decompose in the presence of water, breaking the original unsaturated bonds to produce aldehydes, ketones, and carboxylic acids.

[0044] Ozone possesses extremely strong oxidizing and bactericidal properties, making it one of the strongest oxidants in nature. Its redox potential in water is second only to fluorine. Furthermore, the product of ozone reaction is oxygen, making ozone a highly efficient oxidant without secondary pollution. As a strong oxidant, its characteristics are as follows:

[0045] 1. Can be used for selective oxidation, with high yield of main product;

[0046] 2. It has a low oxidation temperature, strong oxidizing ability under normal pressure, and is beneficial for the oxidation of sensitive substances;

[0047] 3. The reaction rate is fast, and quantitative oxidation can be achieved;

[0048] 4. Easy to use and manufacture.

[0049] Ozone's strong oxidizing properties stem from the strong electrophilic or proton-philic nature of the oxygen atoms in its molecules. After decomposition, ozone produces nascent oxygen atoms, which in water form hydroxyl radicals—strong oxidizing groups—that can rapidly remove organic pollutants from wastewater. Ozone itself decomposes into oxygen, preventing secondary pollution.

[0050] Currently, it is believed that there are two pathways for the reaction between ozone and organic matter:

[0051] 1. Ozone reacts directly with organic matter in water in the form of oxygen molecules. This method is highly selective, generally targeting organic compounds with double bonds, and is particularly effective against aromatic hydrocarbons and unsaturated aliphatic hydrocarbons.

[0052] 2. When ozone decomposes in water, it produces highly oxidizing intermediates such as hydroxyl radicals. These hydroxyl radicals then react with organic compounds in an oxidation process. This oxidation method is non-selective.

[0053] Relevant test data after application by a spandex factory in Hangzhou:

[0054] COD pH ammonia nitrogen Total nitrogen equalization tank <![CDATA[≤ 5000 ]]> 7～9 <![CDATA[≤ 300 ]]> <![CDATA[≤ 350 ]]> UASB produced water <![CDATA[≤15 00 ]]> 7～8 <![CDATA[≤ 300 ]]> <![CDATA[≤ 350 ]]> aerobic end ≤100 7～8 <![CDATA[≤ 3 ]]> <![CDATA[≤ 30 ]]> MBR permeate <![CDATA[≤ 70 ]]> 7～8 <![CDATA[≤ 3 ]]> <![CDATA[≤ 30 ]]> RO permeate <![CDATA[≤ 10 ]]> 7～8 ≤1 ≤5 RO concentrate ≤140 7～8 ≤6 ≤60 AOPs water output <![CDATA[≤ 50 ]]> 7～8 <![CDATA[≤ 3 ]]> ≤60

[0055] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it. Although the utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this utility model.

Claims

1. A comprehensive wastewater treatment system for spandex production, characterized in that: It includes a concentrated wastewater pretreatment unit, a refined wastewater buffer tank, a UASB reactor, an anaerobic sedimentation tank, an anoxic tank, an aerobic tank, a post-denitrification filter, an MBR tank, an MBR permeate tank, an RO unit, and a sedimentation tank, arranged in sequence.

2. The comprehensive wastewater treatment system for spandex production as described in claim 1, characterized in that: The RO device is also connected to a recycled water tank.

3. The comprehensive wastewater treatment system for spandex production as described in claim 1, characterized in that: The sedimentation tank is also connected to the AOP water treatment system.

4. The comprehensive wastewater treatment system for spandex production as described in claim 1, characterized in that: The anaerobic sedimentation tank is also connected to a sludge tank.

5. The comprehensive wastewater treatment system for spandex production as described in claim 4, characterized in that: The sludge tank is connected to a screw press.

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