A sewage treatment device and method for laundry washing

Abstract

The present application relates to a kind of sewage treatment device and method for clothing washing, including the floatstone powder and fiber cyclone separation unit connected in turn, multi-medium coagulation precipitation unit, membrane separation recovery unit and depth oxidation unit and intelligent control unit.The present application applies multi-stage hydrocyclone separation technology to clothing washing wastewater treatment, by first-stage hydrocyclone and second-stage hydrocyclone in series, realize the classification recovery of floatstone particle and floatstone powder according to particle size, and set up floatstone powder recovery bin to carry out vibration fluidization, particle size sorting, spray flushing and hot air drying treatment to the recovered floatstone powder, and then send it back to clothing washing machine through pneumatic conveying pipeline for recycling, which fundamentally realizes the closed-loop recycling of floatstone resources, greatly reduces the procurement cost of floatstone and the amount of solid waste generated, uses spiral extrusion dewatering device to dewater and reduce the volume of fiber residue, realizes the recycling of fiber resources, and ensures the stable operation of subsequent coagulation precipitation and membrane separation unit.

Description

Technical Field

[0001] This invention relates to the field of garment processing technology, specifically to a wastewater treatment device and method for garment washing. Background Technology

[0002] Garment washing is an important post-processing step in garment manufacturing, mainly including various processes such as general washing, stone washing, enzyme washing, rinsing, and frosting. Among them, stone washing requires the addition of natural or artificial pumice stones to the washing machine, and the mechanical friction between the pumice stones and the surface of the garment achieves a whitening and distressing effect; enzyme washing uses cellulase to treat the fibers.

[0003] Garment washing wastewater has a high concentration of suspended solids (SS), with pumice powder making up a significant portion. The pumice powder has a wide particle size distribution, and if directly introduced into subsequent biological treatment systems, it can easily cause pipe wear, pump damage, and packing blockage. The wastewater also has a high content of short fibers, which easily entangle and form flocs, clogging screens and membrane modules. Furthermore, the wastewater contains recalcitrant dyes such as indigo, resulting in high color intensity, high COD concentration, and poor biodegradability. Current technologies for treating garment washing wastewater typically employ a combination of processes including screening, coagulation sedimentation, biological treatment, and advanced treatment.

[0004] However, existing processes often suffer from several drawbacks. Pumice powder and fiber are simply discharged as waste residue along with the sludge, resulting in a huge waste of pumice resources and making the disposal of large amounts of stone powder-containing sludge difficult and costly. Furthermore, a large amount of suspended solids in the wastewater directly enters the biological treatment system, leading to high suspended solids loads in the biological treatment tanks, sludge expansion, and unstable treatment effects. Indigo dye in the wastewater is not recycled but is either oxidized and degraded or discharged with the sludge, resulting in a waste of dye resources. Wastewater from different processes is treated in a mixed manner without being separated according to water quality differences, resulting in large dosages of coagulants and ozone, and high operating costs. Additionally, there is a lack of online water quality monitoring and adaptive control methods, making process operation reliant on manual experience and resulting in poor resistance to shock loads.

[0005] Therefore, there is an urgent need to propose a wastewater treatment device and method for garment washing to solve the above problems. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides a wastewater treatment device and method for garment washing, aiming to achieve the separate, step-by-step separation and comprehensive recycling of pumice powder, fiber, indigo dye, and water resources, thereby reducing operating costs, improving treatment stability, and solving problems in existing garment washing wastewater treatment technologies, such as pumice powder and fiber being discharged as waste residue, resulting in resource waste, suspended solids impacting the biochemical system, lack of indigo dye recovery, insufficient separation of components, large dosage of reagents, and lack of adaptive control.

[0007] To achieve the above objectives, the present invention provides the following technical solution: a wastewater treatment device for garment washing, comprising a pumice powder and fiber cyclone separation unit, a multi-media coagulation sedimentation unit, a membrane separation and recovery unit, a deep oxidation unit, and an intelligent control unit connected in sequence; The pumice powder and fiber cyclone separation unit includes a multi-stage cyclone separation group consisting of a primary hydrocyclone and a secondary hydrocyclone connected in series. The underflow port of the primary hydrocyclone is connected to the inlet of the secondary hydrocyclone, and the underflow port of the secondary hydrocyclone is connected to the pumice powder recovery chamber. The outlet of the pumice powder recovery chamber is connected to the pumice replenishment port of the garment washing machine through a pneumatic conveying pipeline. The overflow ports of the primary and secondary hydrocyclones merge and are connected to a fiber screen. The filtered water from the fiber screen is connected to a multi-media coagulation and sedimentation unit, and the fiber-retaining outlet of the fiber screen is connected to a fiber collector. The multi-media coagulation and sedimentation unit includes a mixing reactor, a flocculation tank and an inclined tube sedimentation tank connected in sequence. The mixing reactor is equipped with a composite coagulant dosing port and a pH adjustment port. The bottom of the inclined tube sedimentation tank is equipped with a sludge discharge port. The upper effluent weir of the inclined tube sedimentation tank is connected to the membrane separation and recovery unit. The membrane separation and recovery unit includes a delivery pump, an ultrafiltration membrane module and a nanofiltration membrane module connected in sequence. The concentrate side of the ultrafiltration membrane module is connected to an indigo dye concentrate collection tank. The indigo dye concentrate collection tank is connected to the dye replenishment port of the garment washing machine through a reuse pipeline. The permeate of the nanofiltration membrane module is connected to the deep oxidation unit. The deep oxidation unit includes an ozone contact reactor, an ozone generator, and a catalyst bed. The ozone generator is connected to the bottom aeration device of the ozone contact reactor through an ozone dosing pipeline. The catalyst bed is located inside the ozone contact reactor, and the effluent end of the ozone contact reactor is connected to the effluent discharge port. The intelligent control unit includes an online COD sensor, an online color sensor, an online turbidity sensor, a programmable controller, and several electric regulating valves. The online COD sensor, online color sensor, and online turbidity sensor are respectively installed at the outlet of each unit and connected to the programmable controller. The programmable controller controls the dosage of composite coagulant, the dosage of ozone, and the opening degree of each electric regulating valve based on the water quality signals collected by each sensor.

[0008] Furthermore, the cone angle, cylinder diameter, and overflow port inner diameter of the primary and secondary hydrocyclones are set according to different gradations. The primary hydrocyclone is used to separate pumice particles with a particle size greater than 0.5 mm, and the secondary hydrocyclone is used to separate pumice powder with a particle size of 0.05 mm to 0.5 mm. The bottom of the pumice powder recovery bin is equipped with a vibrating fluidizing plate and a particle size sorting screen. The particle size sorting screen separates the recovered pumice powder into two paths according to particle size: reusable pumice powder and waste residue.

[0009] Furthermore, the pumice powder recycling bin is also equipped with a spray washing device and a drying air duct. The spray washing device washes the surface of the reusable pumice powder after it has been sorted by the particle size sorting screen to remove the indigo dye and fiber debris attached to the surface of the pumice powder. The drying air duct dries the washed pumice powder with hot air. The dried pumice powder is then sent back to the garment washing machine via a pneumatic conveying pipeline.

[0010] Furthermore, the fiber screener adopts a microporous vibrating screen with a screen aperture of 0.1mm to 0.3mm. The housing of the fiber screener is equipped with a vibrating motor and a spray water pipe. The spray water pipe sprays and washes the screen surface, flushing the intercepted fiber residue into the fiber collector. The fiber collector is equipped with a spiral extrusion dewatering device.

[0011] Furthermore, the mixing reactor is equipped with a stirring paddle, and both the composite coagulant dosing port and the pH adjustment port are equipped with metering pumps. The pH adjustment port is connected to the alkali storage tank and the acid storage tank. The flocculation tank is equipped with a coagulant aid dosing port and a grid flocculation device. The inclined tube sedimentation tank is equipped with inclined tube packing, and the inclination angle of the inclined tube packing is 45° to 60°.

[0012] Furthermore, the ultrafiltration membrane module adopts a hollow fiber ultrafiltration membrane with a molecular weight cutoff of 50kDa to 100kDa, and its concentrate side forms a concentration circulation loop with the indigo dye concentrate collection tank through a first concentrate circulation pump; the nanofiltration membrane module adopts a spiral wound nanofiltration membrane, and its concentrate side is returned to the mixing reactor through a second concentrate circulation pump.

[0013] Furthermore, the indigo dye concentrate collection tank is equipped with a reducing agent dosing port and a stirrer. The reducing agent dosing port adds sodium hydrosulfite or thiourea dioxide reducing agent to the concentrate, so that the insoluble indigo particles are reduced to soluble leuco sodium salt under alkaline conditions and then sent back to the dye replenishment port of the garment washing machine through the recycling pipeline.

[0014] Furthermore, the catalyst bed uses activated alumina balls loaded with manganese oxide or honeycomb ceramics loaded with cerium oxide as ozone catalyst carriers, the bottom aeration device of the ozone contact reactor uses a microporous titanium plate aerator, the ozone contact reactor is equipped with a gas-liquid mixing baffle, and the top of the ozone contact reactor is equipped with a tail gas destroyer.

[0015] Furthermore, the device also includes a grid interception unit located upstream of the pumice powder and fiber cyclone separation unit. The grid interception unit includes a coarse grid and a fine grid arranged in sequence. The grid spacing of the coarse grid is 20mm to 40mm, and the grid spacing of the fine grid is 3mm to 8mm. A water collection and regulating tank is located downstream of the fine grid. The water collection and regulating tank is equipped with a submersible agitator and a lift pump.

[0016] A method for treating garment wastewater using the aforementioned device includes the following steps: S1: The wastewater discharged from the garment washing machine enters the water collection and equalization tank after being intercepted by the bar screen unit to remove large debris and achieve uniform quality and quantity. S2: The homogenized wastewater is pumped into the pumice powder and fiber cyclone separation unit. After being separated by a series of primary and secondary hydrocyclones, the pumice particles and pumice powder are recovered from the bottom outlet to the pumice powder recovery bin. After being cleaned and dried, the wastewater is pneumatically sent back to the garment washing machine for recycling. The overflow liquid from the cyclone enters the fiber screen to intercept the fibers and then enters the multi-media coagulation and sedimentation unit. S3: The separated wastewater is coagulated with a composite coagulant in a mixing reactor after pH adjustment, then enters a flocculation tank where a coagulant aid is added for flocculation, and then undergoes solid-liquid separation in an inclined tube sedimentation tank. The sludge is discharged from the sludge discharge port, and the supernatant enters the membrane separation and recovery unit. S4: The supernatant is pumped into the ultrafiltration membrane module. The indigo dye in the ultrafiltration concentrate is concentrated and collected in the indigo dye concentrate collection tank. After reduction and dissolution, it is sent back to the garment washing machine for recycling. The ultrafiltration permeate enters the nanofiltration membrane module for further separation. The nanofiltration concentrate is returned to the mixing reactor for further treatment. The nanofiltration permeate enters the deep oxidation unit. S5: The nanofiltration permeate comes into full contact with ozone and the catalyst bed in the ozone contact reactor. Under the synergistic catalytic oxidation of ozone, residual organic matter and color are decomposed, and the treated effluent meets the discharge standards or can be reused. S6: The intelligent control unit collects COD, color and turbidity signals from the outlet of each unit in real time. The programmable controller automatically adjusts the dosage of composite coagulant, ozone dosage and opening degree of each electric regulating valve according to water quality changes to achieve adaptive operation of the whole process.

[0017] Compared with the prior art, the technical solution of this application has the following beneficial effects: 1. This invention applies multi-stage hydrocyclone separation technology to garment washing wastewater treatment. By connecting a primary hydrocyclone and a secondary hydrocyclone in series, pumice particles and pumice powder are graded and recovered according to particle size. A pumice powder recovery bin is set up to treat the recovered pumice powder through vibration fluidization, particle size sorting, spray rinsing and hot air drying. After treatment, the powder is returned to the garment washing machine for recycling via a pneumatic conveying pipeline. This fundamentally realizes the closed-loop recycling of pumice resources, significantly reducing the procurement cost of pumice and the amount of solid waste generated.

[0018] 2. This invention sets up a fiber screen and a fiber collector after cyclone separation. The microporous vibrating screen is used to efficiently intercept and recover short fibers and cotton fiber scraps in the wastewater, and a screw extrusion dewatering device is used to dewater and reduce the volume of the fiber residue, thereby realizing the recycling of fiber resources and ensuring the stable operation of the subsequent coagulation sedimentation and membrane separation units.

[0019] 3. This invention utilizes a combination of ultrafiltration and nanofiltration membrane modules to concentrate and recover indigo dye from wastewater into an indigo dye concentrate collection tank. After being reduced and dissolved by a reducing agent into soluble leuco sodium salt, it is returned to the dye replenishment port of a garment washing machine via a reuse pipeline, achieving online recovery and recycling of indigo dye and significantly reducing dye consumption. Ozone synergistic catalytic oxidation is employed as a deep treatment unit, enhancing the oxidizing capacity of ozone through a catalyst bed to achieve efficient decomposition of recalcitrant organic matter and color.

[0020] 4. This invention features an intelligent control unit that collects real-time water quality signals from each unit via online COD, color, and turbidity sensors. The programmable controller automatically adjusts the dosage of composite coagulant, ozone, and the opening of each electric regulating valve, achieving adaptive operation throughout the entire process. It has strong resistance to shock loads, is easy to operate and manage, and significantly reduces the consumption of chemicals and energy. Attached Figure Description

[0021] Figure 1 This is an overall framework diagram of the present invention; Figure 2 This is a schematic diagram of the pumice powder and fiber cyclone separation unit structure of the present invention; Figure 3 This is a schematic diagram of the multi-media coagulation and sedimentation unit structure of the present invention; Figure 4 This is a schematic diagram of the membrane separation and recovery unit structure of the present invention; Figure 5 This is a schematic diagram of the deep oxidation unit structure of the present invention; Figure 6 This is a schematic diagram of the intelligent control unit structure of the present invention; Figure 7 This is a flowchart of the wastewater treatment method for garment washing according to the present invention.

[0022] In the picture: 1. Pumice powder and fiber hydrocyclone separation unit; 11. Primary hydrocyclone; 12. Secondary hydrocyclone; 13. Pumice powder recovery bin; 131. Vibrating fluidizing plate; 132. Particle size sorting screen; 133. Spray washing device; 134. Drying air duct; 14. Pneumatic conveying pipeline; 15. Fiber screener; 151. Vibrating motor; 152. Spray water pipe; 16. Fiber collector; 2. Multi-media coagulation and sedimentation unit; 21. Mixing reactor; 211. Agitator; 22. Flocculation tank; 221. Coagulant dosing port; 222. Grid flocculation device; 23. Inclined tube sedimentation tank; 231. Inclined tube packing; 24. Composite coagulant dosing port; 241. Metering pump; 25. pH adjustment port; 26. Sludge discharge port; 3. Membrane separation and recovery unit; 31. Transfer pump; 32. Ultrafiltration membrane module; 321. First concentrate circulation pump; 33. Nanofiltration membrane module; 331. Second concentrate circulation pump; 34. Indigo dye concentrate collection tank; 341. Reducing agent dosing port; 342. Stirrer; 35. Reuse pipeline; 4. Deep oxidation unit; 41. Ozone contact reactor; 411. Microporous titanium plate aerator; 412. Gas-liquid mixing baffle; 413. Tail gas destroyer; 42. Ozone generator; 43. Catalyst bed; 44. Water discharge outlet; 5. Intelligent control unit; 51. Online COD sensor; 52. Online colorimetric sensor; 53. Online turbidity sensor; 54. Programmable controller; 55. Electric regulating valve; 7. Bar screen unit; 71. Coarse bar screen; 72. Fine bar screen; 73. Water collection and regulating tank; 74. Submersible mixer; 75. Booster pump. Detailed Implementation

[0023] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] Example 1 like Figure 1 As shown, the present invention provides a wastewater treatment device for garment washing, comprising a pumice powder and fiber cyclone separation unit 1, a multi-media coagulation sedimentation unit 2, a membrane separation and recovery unit 3, a deep oxidation unit 4, and an intelligent control unit 5 connected in sequence. The device also includes a grid interception unit 7 disposed upstream of the pumice powder and fiber cyclone separation unit 1.

[0025] The bar screen interception unit 7 includes a coarse bar 71 and a fine bar 72 arranged sequentially. The coarse bar 71 has a grid spacing of 20mm to 40mm and is used to intercept large debris such as buttons, zippers, and thread ends carried in the washing wastewater. The fine bar 72 has a grid spacing of 3mm to 8mm and is used to further intercept finer suspended solids. Downstream of the fine bar 72, a water collection and equalization tank 73 is provided. The water collection and equalization tank 73 is equipped with a submersible agitator 74 and a lift pump 75. The submersible agitator 74 homogenizes and equalizes the wastewater, and the lift pump 75 pumps the wastewater in the equalization tank to the pumice powder and fiber cyclone separation unit 1.

[0026] like Figure 2 As shown, the pumice powder and fiber cyclone separation unit 1 includes a multi-stage cyclone separation group consisting of a primary hydrocyclone 11 and a secondary hydrocyclone 12 connected in series.

[0027] The cone angle, cylinder diameter, and overflow port inner diameter of the primary hydrocyclone 11 and the secondary hydrocyclone 12 are set according to different gradations: the primary hydrocyclone 11 has a larger cylinder diameter and a smaller cone angle, mainly used to separate pumice particles with a particle size greater than 0.5 mm; the secondary hydrocyclone 12 has a smaller cylinder diameter and a larger cone angle, mainly used to separate pumice powder with a particle size of 0.05 mm to 0.5 mm. Wastewater is sent to the primary hydrocyclone 11 by the lift pump 75 of the collection and equalization tank 73. Inside the primary hydrocyclone 11, under the action of centrifugal force, the denser pumice particles move downward along the wall and are discharged from the bottom outlet, while the overflow containing fine particles enters the secondary hydrocyclone 12 for further separation.

[0028] The underflow port of the primary hydrocyclone 11 is connected to the feed inlet of the secondary hydrocyclone 12, and the underflow port of the secondary hydrocyclone 12 is connected to the pumice powder recovery bin 13. The bottom of the pumice powder recovery bin 13 is equipped with a vibrating fluidizing plate 131 and a particle size separation screen 132. The vibrating fluidizing plate 131 drives the recovered pumice powder to vibrate and fluidize, ensuring uniform dispersion. The particle size separation screen 132 separates the pumice powder into two streams based on particle size: reusable pumice powder and fine waste residue. The pumice powder recovery bin 13 is also equipped with a spray washing device 133 and a drying duct 134. The spray washing device 133 performs surface washing on the separated reusable pumice powder, removing indigo dye and fiber debris adhering to the surface. The washing wastewater is returned to the collection and regulating tank 73. The drying duct 134 sends hot air into the bin to dry the washed pumice powder. The dried pumice powder is sent back to the pumice replenishment port of the garment washing machine through the pneumatic conveying pipeline 14, realizing the recycling of pumice.

[0029] The overflow ports of the primary hydrocyclone 11 and the secondary hydrocyclone 12 converge and connect to the fiber screen 15. The fiber screen 15 is a microporous vibrating screen with a screen aperture of 0.1 mm to 0.3 mm. The housing of the fiber screen 15 is equipped with a vibrating motor 151 and a spray water pipe 152. After the wastewater enters the fiber screen 15, under the vibration of the vibrating motor 151, the wastewater with a particle size smaller than the screen aperture passes through the screen and is discharged into the multi-media coagulation and sedimentation unit 2. The short fibers and cotton fiber debris retained on the screen surface are flushed into the fiber collector 16 under the spray washing action of the spray water pipe 152. The fiber collector 16 is equipped with a spiral extrusion dewatering device 161 to extrude, dewater, and reduce the volume of the fiber residue. The dewatered water flows back to the water collection and regulating tank 73, and the dewatered fiber residue can be recycled as raw material for regenerated fibers.

[0030] like Figure 3 As shown, the multi-media coagulation and sedimentation unit 2 includes a mixing reactor 21, a flocculation tank 22, and an inclined tube sedimentation tank 23 connected in sequence.

[0031] The mixing reactor 21 is equipped with a stirring paddle 211 and a composite coagulant dosing port 24 and a pH adjustment port 25. Both the composite coagulant dosing port 24 and the pH adjustment port 25 are equipped with metering pumps 241. The pH adjustment port 25 is connected to an alkali storage tank and an acid storage tank. Wastewater treated by the fiber screen 15 enters the mixing reactor 21. First, alkali or acid is added through the pH adjustment port 25 to adjust the pH of the wastewater to a suitable range (6.5 to 8.5). Then, a composite coagulant (such as a compound system of polyaluminum chloride and polyacrylamide) is added to the wastewater through the composite coagulant dosing port 24. Under the rapid stirring of the stirring paddle 211, the colloidal particles destabilize and coagulate to form fine flocs.

[0032] The wastewater treated by the mixing reactor 21 enters the flocculation tank 22. The flocculation tank 22 is equipped with a coagulant dosing port 221 and a grid flocculation device 222. A coagulant aid (such as polyacrylamide) is added through the coagulant dosing port 221, and under the grid flocculation effect of the grid flocculation device 222, fine flocs collide, aggregate, and grow into large and dense flocs during slow flow. The flocculated wastewater then enters the inclined tube sedimentation tank 23. The inclined tube sedimentation tank 23 is equipped with inclined tube packing 231, with an inclination angle of 45° to 60°. The wastewater flows upwards in the inclined tube sedimentation tank 23, while the flocs settle within the inclined tubes and slide down to the bottom of the tank, where they are discharged through the bottom sludge discharge port 26. The supernatant flows into the membrane separation and recovery unit 3 via the upper effluent weir. The discharged sludge enters the sludge thickening and dewatering system for further treatment.

[0033] like Figure 4 As shown, the membrane separation and recovery unit 3 includes a transfer pump 31, an ultrafiltration membrane module 32, and a nanofiltration membrane module 33 connected in sequence.

[0034] The supernatant from the effluent weir of the inclined tube sedimentation tank 23 is pressurized by the transfer pump 31 and then enters the ultrafiltration membrane module 32. The ultrafiltration membrane module 32 adopts a hollow fiber ultrafiltration membrane with a molecular weight cutoff of 50kDa to 100kDa. Under the action of membrane separation, large molecular organic matter, colloidal particles and indigo dye particles in the wastewater are retained by the ultrafiltration membrane to form concentrated water, while water molecules and small molecules pass through the ultrafiltration membrane to form permeate.

[0035] The concentrate side of the ultrafiltration membrane module 32 forms a concentration circulation loop with the indigo dye concentrate collection tank 34 via the first concentrate circulation pump 321. The concentrate circulates and concentrates in the loop, and the concentration of indigo dye continuously increases. The indigo dye concentrate collection tank 34 is equipped with a reducing agent dosing port 341 and a stirrer 342. Sodium dithionite or thiourea dioxide reducing agent is added to the concentrate through the reducing agent dosing port 341. Under the stirring action of the stirrer 342, the insoluble indigo particles are reduced to soluble leuco sodium salt under alkaline conditions. The dye solution after reduction and dissolution is returned to the dye replenishment port of the garment washing machine through the recycling pipeline 35, realizing the online recovery and recycling of indigo dye.

[0036] The permeate from the ultrafiltration membrane module 32 enters the nanofiltration membrane module 33, which uses a spiral wound nanofiltration membrane. Under the selective retention of the nanofiltration membrane, the residual dye molecules, dissolved organic matter and divalent ions in the permeate are further retained. The nanofiltration concentrate is returned to the mixing reactor 21 for further treatment via the second concentrate circulation pump 331. The trace organic matter remaining in the nanofiltration permeate enters the deep oxidation unit 4.

[0037] like Figure 5 As shown, the deep oxidation unit 4 includes an ozone contact reactor 41, an ozone generator 42, and a catalyst bed 43.

[0038] Ozone generator 42 employs a corona discharge type to produce high-concentration ozone, which is then delivered to the bottom aeration device of the ozone contact reactor 41 via an ozone dosing pipeline. The bottom aeration device uses a microporous titanium plate aerator 411, which disperses the ozone into fine bubbles, ensuring uniform diffusion into the wastewater for thorough oxidation. The ozone contact reactor 41 is equipped with a gas-liquid mixing baffle 412, which extends the residence path of ozone within the reactor, enhancing gas-liquid mass transfer and improving ozone utilization. A catalyst bed 43 is located inside the ozone contact reactor 41, above the microporous titanium plate aerator 411. The catalyst bed 43 uses activated alumina balls loaded with manganese oxide or honeycomb ceramics loaded with cerium oxide as the ozone catalyst carrier. Under the action of the catalyst, ozone decomposes to generate hydroxyl radicals with stronger oxidizing power, efficiently decomposing residual recalcitrant organic matter and color substances in the wastewater into carbon dioxide and water. The ozone contact reactor 41 is equipped with a tail gas destroyer 413 at the top, which heats and decomposes unreacted ozone in the tail gas to prevent ozone from escaping and polluting the environment. The effluent after deep treatment is discharged through the effluent outlet 44 of the ozone contact reactor 41 in compliance with standards, or it can be reused in the rinsing stage of the garment washing process.

[0039] like Figure 6As shown, the intelligent control unit 5 includes an online COD sensor 51, an online color sensor 52, an online turbidity sensor 53, a programmable controller 54, and several electric regulating valves 55.

[0040] An online COD sensor 51 is installed at the outlet of the deep oxidation unit 4, an online color sensor 52 is installed at the outlet of the membrane separation and recovery unit 3, and an online turbidity sensor 53 is installed at the outlet of the multi-media coagulation and sedimentation unit 2. Each sensor transmits the collected water quality signals to the programmable controller 54 in real time. Based on the water quality signals collected by each sensor, the programmable controller 54 automatically adjusts the dosage of the metering pump 241 at the composite coagulant dosing port 24, the dosage of the pH adjustment port 25, the ozone dosage of the ozone generator 42, and the opening degree of each electric regulating valve 55 through a preset control algorithm, achieving adaptive optimization operation of the entire process. For example, when the online color sensor 52 detects an increase in the color of the effluent from the membrane separation and recovery unit 3, the programmable controller 54 automatically increases the ozone dosage of the ozone generator 42 and adjusts the opening degree of the electric regulating valve 55 to ensure that the effluent meets the standards.

[0041] Example 2 like Figure 7 As shown, this embodiment provides a method for treating garment washing wastewater using the above-mentioned device, including the following steps: S1 Bar Screen Interception and Homogenization Adjustment: The wastewater discharged from the garment washing machine first flows through the bar screen interception unit 7. After passing through the coarse bar screen 71 to intercept large debris such as buttons, zippers, and thread ends, and then passing through the fine bar screen 72 to intercept finer suspended solids, it enters the water collection and adjustment tank 73. Under the stirring action of the submersible agitator 74, the water volume and quality are homogenized and adjusted to prevent shock load.

[0042] S2 Cyclone Separation and Resource Recycling: Wastewater in the collection and equalization tank 73 is pumped into the pumice powder and fiber cyclone separation unit 1 via the lift pump 75. The wastewater first enters the primary hydrocyclone 11, separating pumice particles larger than 0.5mm. The underflow from the primary hydrocyclone 11 enters the secondary hydrocyclone 12, further separating pumice powder with a particle size of 0.05mm to 0.5mm. The underflow pumice powder from both hydrocyclones enters the pumice powder recovery bin 13, where it is classified under the action of the vibrating fluidizing plate 131 and the particle size sorting screen 132. Reusable pumice powder is washed by the spray washing device 133 to remove surface indigo dye and fiber debris, then dried with hot air through the drying duct 134, and finally returned to the pumice replenishment port of the garment washing machine for recycling via the pneumatic conveying pipeline 14. The overflow from the two-stage hydrocyclone merges into the fiber screen 15. Under the action of the vibrating motor 151 and the spray water pipe 152, the screened water enters the multi-media coagulation sedimentation unit 2, and the retained fiber residue enters the fiber collector 16 and is dewatered and recycled by the screw extrusion dewatering device 161.

[0043] S3 Coagulation and Sedimentation: The wastewater after S2 separation enters the mixing reactor 21 of the multi-media coagulation and sedimentation unit 2. First, the pH of the wastewater is adjusted to 6.5 to 8.5 through the pH adjustment port 25. Then, the composite coagulant is added through the composite coagulant dosing port 24. Under the rapid stirring of the agitator 211, coagulation and destabilization occur. The wastewater enters the flocculation tank 22. The coagulant aid is added through the coagulant aid dosing port 221 and flocculates into flocs under the action of the grid flocculation device 222. The flocculated wastewater enters the inclined tube sedimentation tank 23. After solid-liquid separation by the inclined tube packing 231, the sludge is discharged through the sludge discharge port 26, and the supernatant enters the membrane separation and recovery unit 3.

[0044] S4 Membrane Separation and Dye Recycling: The supernatant enters the ultrafiltration membrane module 32 via the transfer pump 31. Macromolecular organic matter and indigo dye particles are retained by the ultrafiltration membrane. The concentrate is circulated and concentrated in the indigo dye concentrate collection tank 34 via the first concentrate circulation pump 321. Sodium hydrosulfite or thiourea dioxide reducing agent is added to the concentrate to reduce insoluble indigo to soluble leuco sodium salt, which is then returned to the dye replenishment port of the garment washing machine via the recycling pipeline 35 for recycling. The ultrafiltration permeate enters the nanofiltration membrane module 33 for further retention of dissolved organic matter and ions. The nanofiltration concentrate is returned to the mixing reactor 21 for further treatment via the second concentrate circulation pump 331. The nanofiltration permeate enters the deep oxidation unit 4.

[0045] S5 Ozone Catalytic Deep Oxidation: Nanofiltration permeate enters ozone contact reactor 41. Ozone generated by ozone generator 42 is dispersed into microbubbles by microporous titanium plate aerator 411 and comes into full contact with wastewater. Under the catalytic action of catalyst bed 43, it decomposes to generate hydroxyl radicals, which efficiently oxidize and decompose residual recalcitrant organic matter and color. The effluent is discharged through effluent outlet 44 in compliance with standards or reused. The tail gas is treated by tail gas destroyer 413 before being discharged.

[0046] S6 Intelligent Adaptive Control: During the operation of the above steps, the online COD sensor 51, online color sensor 52 and online turbidity sensor 53 of the intelligent control unit 5 collect the water quality signals of the effluent from each unit in real time and transmit them to the programmable controller 54. The programmable controller 54 automatically adjusts the dosage of composite coagulant, pH adjustment dosage, ozone dosage and the opening degree of each electric regulating valve 55 according to the water quality changes, so as to realize the adaptive optimization operation of the whole process and ensure that the effluent meets the standards stably.

[0047] Example 3 This embodiment illustrates the process and effect of treating wastewater from a denim garment washing plant using the apparatus and method of the present invention. The plant's wastewater treatment capacity is designed to be 2000 m³ / h. 3 / d, mainly from stone washing, enzyme washing and rinsing processes. The average COD concentration of the influent is 1800mg / L, the color is 800 times, the suspended solids (SS) concentration is 1200mg / L, of which pumice powder content is about 650mg / L and short fiber content is about 150mg / L.

[0048] After large impurities are removed by the bar screen interception unit 7, the wastewater enters the collection and equalization tank 73 for homogenization. It is then treated by the pumice powder and fiber cyclone separation unit 1, with a pumice powder recovery rate of over 92%. The recovered pumice powder is washed, dried, and reused, and the fiber retention rate is greater than 95%. The separated wastewater enters the multi-media coagulation and sedimentation unit 2, where a composite coagulant of polyaluminum chloride and polyacrylamide is added, reducing the SS in the effluent to below 60 mg / L and the turbidity removal rate to 98%. The supernatant enters the membrane separation and recovery unit 3, where ultrafiltration and nanofiltration are combined to concentrate and recover the indigo dye in the wastewater, with an indigo dye recovery rate of over 85%, which is then reused in the dyeing process. The nanofiltration permeate enters the deep oxidation unit 4, where, under the synergistic catalytic oxidation of ozone and a catalyst bed, the COD in the effluent is reduced to below 40 mg / L and the color is reduced to below 5 times, meeting the indirect discharge requirements of the "Water Pollutant Discharge Standard for Textile Dyeing and Finishing Industry" (GB4287-2012). Part of the treated effluent is reused in the rinsing process, and the overall water reuse rate reaches over 60%. During operation, the intelligent control unit 5 automatically adjusts the dosage of chemicals and ozone based on online water quality signals, ensuring long-term stable operation that meets standards. The dosage of chemicals is reduced by about 30% compared to traditional mixed treatment processes, resulting in a significant decrease in operating costs.

[0049] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0050] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A wastewater treatment device for garment washing, comprising a pumice powder and fiber cyclone separation unit (1), a multi-media coagulation sedimentation unit (2), a membrane separation and recovery unit (3), a deep oxidation unit (4), and an intelligent control unit (5) connected in sequence. The pumice powder and fiber cyclone separation unit (1) includes a multi-stage cyclone separation group consisting of a primary hydrocyclone (11) and a secondary hydrocyclone (12) connected in series. The underflow port of the primary hydrocyclone (11) is connected to the feed port of the secondary hydrocyclone (12), and the underflow port of the secondary hydrocyclone (12) is connected to the pumice powder recovery chamber (13). The discharge end of the pumice powder recovery chamber (13) is connected to the pumice feed port of the garment washing machine through a pneumatic conveying pipeline (14). The overflow ports of the primary hydrocyclone (11) and the secondary hydrocyclone (12) are connected to the fiber screen (15). The filtered water of the fiber screen (15) is connected to the multi-media coagulation sedimentation unit (2), and the fiber interception outlet of the fiber screen (15) is connected to the fiber collector (16). The multi-media coagulation sedimentation unit (2) includes a mixing reactor (21), a flocculation tank (22) and an inclined tube sedimentation tank (23) connected in sequence. The mixing reactor (21) is provided with a composite coagulant dosing port (24) and a pH adjustment port (25). The bottom of the inclined tube sedimentation tank (23) is provided with a sludge discharge port (26). The upper effluent weir of the inclined tube sedimentation tank (23) is connected to the membrane separation and recovery unit (3). The membrane separation and recovery unit (3) includes a delivery pump (31), an ultrafiltration membrane module (32), and a nanofiltration membrane module (33) connected in sequence. The concentrate side of the ultrafiltration membrane module (32) is connected to an indigo dye concentrate collection tank (34). The indigo dye concentrate collection tank (34) is connected to the dye replenishment port of the garment washing machine through a reuse pipeline (35). The permeate of the nanofiltration membrane module (33) is connected to the deep oxidation unit (4). The deep oxidation unit (4) includes an ozone contact reactor (41), an ozone generator (42), and a catalyst bed (43). The ozone generator (42) is connected to the bottom aeration device of the ozone contact reactor (41) through an ozone dosing pipeline. The catalyst bed (43) is located inside the ozone contact reactor (41). The outlet of the ozone contact reactor (41) is connected to the outlet (44). The intelligent control unit (5) includes an online COD sensor (51), an online color sensor (52), an online turbidity sensor (53), a programmable controller (54), and several electric regulating valves (55). The online COD sensor (51), online color sensor (52), and online turbidity sensor (53) are respectively installed at the outlet of each unit and connected to the programmable controller (54). The programmable controller (54) controls the dosage of composite coagulant, the dosage of ozone, and the opening degree of each electric regulating valve (55) according to the water quality signals collected by each sensor.

2. The wastewater treatment device for garment washing according to claim 1, characterized in that: The cone angle, cylinder diameter and overflow port inner diameter of the primary hydrocyclone (11) and the secondary hydrocyclone (12) are set according to different gradations. The primary hydrocyclone (11) is used to separate pumice particles with a particle size greater than 0.5 mm, and the secondary hydrocyclone (12) is used to separate pumice powder with a particle size of 0.05 mm to 0.5 mm. The bottom of the pumice powder recovery bin (13) is provided with a vibrating fluidizing plate (131) and a particle size sorting screen (132). The particle size sorting screen (132) separates the recovered pumice powder into two paths according to the particle size: reusable pumice powder and waste residue.

3. The wastewater treatment device for garment washing according to claim 2, characterized in that: The pumice powder recycling bin (13) is also equipped with a spray washing device (133) and a drying air duct (134). The spray washing device (133) washes the surface of the reusable pumice powder after it has been sorted by the particle size sorting screen (132) to remove the indigo dye and fiber debris attached to the surface of the pumice powder. The drying air duct (134) dries the washed pumice powder with hot air. The dried pumice powder is then sent back to the garment washing machine via the pneumatic conveying pipeline (14).

4. The wastewater treatment device for garment washing according to claim 1, characterized in that: The fiber screen (15) is a microporous vibrating screen with a screen hole diameter of 0.1 mm to 0.3 mm. The housing of the fiber screen (15) is equipped with a vibrating motor (151) and a spray water pipe (152). The spray water pipe (152) sprays and washes the screen surface, and flushes the intercepted fiber residue into the fiber collector (16). The fiber collector (16) is equipped with a spiral extrusion dewatering device.

5. A wastewater treatment device for garment washing according to claim 1, characterized in that: The mixing reactor (21) is equipped with a stirring paddle (211), and both the composite coagulant dosing port (24) and the pH adjustment port (25) are equipped with metering pumps (241). The pH adjustment port (25) is connected to the alkali storage tank and the acid storage tank. The flocculation tank (22) is equipped with a coagulant aid dosing port (221) and a grid flocculation device (222). The inclined tube sedimentation tank (23) is equipped with inclined tube packing (231), and the inclination angle of the inclined tube packing (231) is 45° to 60°.

6. A wastewater treatment device for garment washing according to claim 1, characterized in that: The ultrafiltration membrane module (32) adopts a hollow fiber ultrafiltration membrane with a molecular weight cutoff of 50kDa to 100kDa. Its concentrate side forms a concentration circulation loop with the indigo dye concentrate collection tank (34) through the first concentrate circulation pump (321). The nanofiltration membrane module (33) adopts a spiral wound nanofiltration membrane. Its concentrate side is connected back to the mixing reactor (21) through the second concentrate circulation pump (331).

7. A wastewater treatment device for garment washing according to claim 6, characterized in that: The indigo dye concentrate collection tank (34) is equipped with a reducing agent dosing port (341) and a stirrer (342). The reducing agent dosing port (341) adds sodium hydrosulfite or thiourea dioxide reducing agent to the concentrate, so that the insoluble indigo particles are reduced to soluble leuco sodium salt under alkaline conditions and then sent back to the dye replenishment port of the garment washing machine through the recycling pipeline (35).

8. A wastewater treatment device for garment washing according to claim 1, characterized in that: The catalyst bed (43) uses activated alumina balls loaded with manganese oxide or honeycomb ceramic loaded with cerium oxide as ozone catalyst carrier. The bottom aeration device of the ozone contact reactor (41) is a microporous titanium plate aerator (411). The ozone contact reactor (41) is equipped with a gas-liquid mixing baffle (412) inside and a tail gas destroyer (413) at the top of the ozone contact reactor (41).

9. A wastewater treatment device for garment washing according to claim 1, characterized in that: The device also includes a grid interception unit (7) located upstream of the pumice powder and fiber cyclone separation unit (1). The grid interception unit (7) includes a coarse grid (71) and a fine grid (72) arranged in sequence. The grid spacing of the coarse grid (71) is 20 mm to 40 mm, and the grid spacing of the fine grid (72) is 3 mm to 8 mm. A water collection and regulating tank (73) is located downstream of the fine grid (72). A submersible agitator (74) and a lift pump (75) are installed in the water collection and regulating tank (73).

10. A method for treating garment wastewater using the apparatus according to any one of claims 1-9, characterized in that: Includes the following steps: S1: The wastewater discharged from the garment washing machine is filtered by the bar screen unit (7) to intercept large debris and then enters the water collection and equalization tank (73) for homogenization and equalization. S2: The homogenized wastewater is pumped into the pumice powder and fiber cyclone separation unit (1), and separated by a series of first-stage hydrocyclone (11) and second-stage hydrocyclone (12). The pumice particles and pumice powder are recovered from the bottom outlet to the pumice powder recovery bin (13). After cleaning and drying, the pumice is pneumatically sent back to the garment washing machine for recycling. The overflow liquid of the cyclone enters the fiber screen (15) to intercept the fibers and then enters the multi-media coagulation sedimentation unit (2). S3: The separated wastewater is mixed with a composite coagulant in the mixing reactor (21) after pH adjustment, and then enters the flocculation tank (22) where a coagulant aid is added for flocculation. After solid-liquid separation in the inclined tube sedimentation tank (23), the sludge is discharged from the sludge discharge port (26), and the supernatant enters the membrane separation and recovery unit (3). S4: The supernatant enters the ultrafiltration membrane module (32) via the transfer pump (31). The indigo dye in the ultrafiltration concentrate is concentrated and collected in the indigo dye concentrate collection tank (34). After reduction and dissolution, it is sent back to the garment washing machine for recycling. The ultrafiltration permeate enters the nanofiltration membrane module (33) for further separation. The nanofiltration concentrate is returned to the mixing reactor (21) for further treatment. The nanofiltration permeate enters the deep oxidation unit (4). S5: The nanofiltration permeate is in full contact with ozone and catalyst bed (43) in the ozone contact reactor (41), and decomposes residual organic matter and color under the synergistic catalytic oxidation of ozone, so that the treated effluent meets the discharge standards or can be reused. S6: The intelligent control unit (5) collects COD, color and turbidity signals from the outlet of each unit in real time. The programmable controller (54) automatically adjusts the dosage of composite coagulant, ozone dosage and opening degree of each electric regulating valve (55) according to water quality changes to achieve full-process adaptive operation.

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