A method and device for treating waste water from a process for recycling waste textiles

Abstract

The application discloses a kind of waste textile regeneration process wastewater treatment method and device.The device includes sequentially through pipeline connection's coagulation sedimentation tank, UASB reactor, low oxygen reactor, high-efficiency sedimentation tank and autotrophic denitrification filter tank, wherein the coagulation sedimentation tank is used for coagulation sedimentation, remove the heavy metal and part of organic matter attached to suspended solids in wastewater;The UASB reactor is used for anaerobic reaction, remove high-concentration organic matter in wastewater and decompose refractory organic matter into small-molecule organic matter;The low oxygen reactor is used for anoxic / aerobic biochemical reaction, remove organic matter, ammonia nitrogen and total nitrogen in wastewater;The high-efficiency sedimentation tank is used for sludge settlement;The autotrophic denitrification filter tank is used for autotrophic reaction, remove total nitrogen in wastewater.The device and processing technology of the application can realize the efficient removal of pollutants such as characteristic organic matter, ammonia nitrogen and total nitrogen for waste polyester resource utilization process wastewater.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of chemical industry and environmental protection, and particularly relates to a device for treating waste water in a waste textile regeneration process, and a treatment process for waste water in a waste textile regeneration process. BACKGROUND

[0002] The resourceization of waste polyester textiles can effectively realize the recycling of waste polyester, and is an environmentally friendly and renewable process path. The tail gas generated in each process device during the depolymerization of waste polyester textiles needs to be treated by a tail gas washing tower before being discharged, and the tail gas washing tower discharge water contains high-concentration organic matter generated by the degradation of polyester, and the composition is complex. Since the waste polyester also contains a small amount of spandex and heavy metals, the degradation of spandex causes nitrogen-containing pollutants to enter the sewage system, resulting in high concentrations of ammonia nitrogen and total nitrogen, which poses a series of problems for wastewater treatment.

[0003] CN108892333A discloses a high-concentration organic wastewater treatment process and system, which includes a biochemical treatment process and a deep treatment process. The biochemical treatment process is arranged before the deep treatment process, and is used for biodegradation of wastewater. The deep treatment process includes the following steps: S1, performing super-magnetic separation on the effluent after the biochemical treatment process to remove phosphorus and reduce turbidity; S2, filtering the effluent after the super-magnetic separation in a filtering device to make the concentration of suspended solids in the filtered effluent less than or equal to 10 mg / L; and S3, performing adsorption treatment on the effluent after the filtering by using SMRES resin. In this patent, COD and ammonia nitrogen in the wastewater can be removed by the biochemical treatment, super-magnetic separation, filtering, resin adsorption, and reverse osmosis processes. However, this technical process is long, the magnetic flocculation and resin adsorption treatment are costly, and the separation and regeneration are difficult.

[0004] CN215905999U discloses an acidic high-concentration organic wastewater treatment system, which includes a primary treatment system and a secondary treatment system. The primary treatment system includes a conditioning tank, a pretreatment tank, and a primary oxidation tank connected in sequence. The secondary treatment system includes a secondary oxidation tank and a secondary sedimentation tank connected in sequence. A circulation pipeline is arranged between the secondary oxidation tank and the primary oxidation tank, and a part of the effluent of the secondary oxidation tank is circulated to the water inlet end of the primary oxidation tank. This patent includes a two-stage treatment system, and uses a multi-stage oxidation process to effectively remove organic matter in the wastewater and improve the oxidation efficiency. However, the use of advanced oxidation technology to treat high-concentration organic matter is costly, and a large amount of iron sludge is generated.

[0005] At present, there is no treatment process for pollutants generated in the resource utilization process of waste polyester, and the related process for treating high-concentration organic wastewater cannot remove the characteristic pollutants generated in the waste polyester resource utilization process. Therefore, the present application studies the wastewater generated in the waste polyester resource utilization process, and accordingly develops a process and device for efficient removal of characteristic pollutants in wastewater. SUMMARY

[0006] In view of the above problems existing in the prior art, the present application provides a new waste textile regeneration process wastewater treatment device and treatment process, which can realize efficient removal of characteristic organic matter, ammonia nitrogen, total nitrogen and other pollutants in the wastewater generated in the waste polyester resource utilization process.

[0007] The first aspect of the present application provides a waste textile regeneration process wastewater treatment device, which comprises a coagulation sedimentation tank, a UASB reactor, a low-oxygen reactor, an efficient sedimentation tank and an autotrophic denitrification filter tank connected in sequence by pipelines, wherein the coagulation sedimentation tank is used for coagulation and sedimentation to remove heavy metals and part of organic matter attached to suspended solids in the wastewater; the UASB reactor is filled with granular sludge and functional carriers for anaerobic reaction to remove high-concentration organic matter in the wastewater and decompose refractory organic matter into small-molecule organic matter; the low-oxygen reactor is used for anoxic / aerobic biochemical reaction to remove organic matter, ammonia nitrogen and total nitrogen in the wastewater; the efficient sedimentation tank is used for sludge sedimentation; and the autotrophic denitrification filter tank is filled with denitrification filler for autotrophic reaction to remove total nitrogen in the wastewater.

[0008] According to some embodiments of the device of the present application, in order to remove suspended solids and heavy metal pollutants in the wastewater and reduce their adverse effects on biochemical reaction, the wastewater generated in the waste polyester resource utilization process is first sent to the coagulation sedimentation tank, and coagulation reagents are added to remove suspended solids, heavy metals and part of organic matter. The coagulation reagents are added in the coagulation sedimentation tank, wherein the coagulation reagents include flocculants and coagulants; preferably, the flocculants are PFS, and preferably, the coagulants are cationic PAM.

[0009] According to some embodiments of the device of the present application, the UASB reactor is inoculated with ordinary flocculent sludge, which can attach to the carrier to form granular sludge. The filling ratio of the functional carrier in the UASB reactor is 5-20% by volume. The UASB reactor performs high-efficiency anaerobic reaction under the action of the granular sludge. However, the granular sludge is prone to disintegration due to the impact of the incoming water, thereby reducing the particle size and the amount of sludge in the reactor. Therefore, the light functional carrier is added to the reactor to maintain the properties of the granular sludge and proliferate the granular sludge to obtain a high sludge retention concentration, so that the reactor can operate well under high load conditions. In addition, the granular sludge formed in the reactor has high microbial density and excellent settling performance, and is easy to separate solid and liquid.

[0010] According to some embodiments of the device of the present application, the average particle size of the functional carrier is 0.5-2.5 mm, preferably 0.7-1.5 mm.

[0011] According to some embodiments of the device of the present application, the specific surface area of the functional carrier is 1-100 m 2 / g, preferably 10-60 m 2 / g.

[0012] According to some embodiments of the device of the present application, the apparent density of the functional carrier is 0.20-0.80 g / cm 3 , preferably 0.45-0.75 g / cm 3 .

[0013] According to some embodiments of the device of the present application, the water-containing density of the functional carrier is 1.0-1.1 kg / L, and the upward flow rate after biofilm formation is 10-40 m / h.

[0014] According to some embodiments of the device of the present application, the preparation method of the functional carrier comprises: mixing one or more polyolefin resins with an antioxidant and a filler, then feeding the mixture into an extrusion molding machine, and drawing the material strip through a pelletizer to obtain granules; drying the granules, and then feeding them into a supercritical fluid treatment device to control the process temperature, pressure, immersion time, pressure release rate and other conditions to obtain a functional carrier with high surface roughness, and to control the apparent density, pore structure and specific surface area of the functional carrier.

[0015] According to some embodiments of the device of the present application, preferably, the weight of the antioxidant is 0.05-1 parts based on 100 parts of the weight of the polyolefin resin, and the weight of the filler is 0.5-30 parts.

[0016] According to some embodiments of the device of the present application, preferably, the polyolefin resin is selected from one or more of polypropylene, polyethylene, polybutylene and polyamylene. For example, but not limited to: polyethylene resin, homopolymer polypropylene T30s, LDPE LD100AC, high melt strength polypropylene HMS20Z, LD100AC, etc.

[0017] According to some embodiments of the device of the present application, the antioxidant can use any antioxidant commonly used in the art, preferably the antioxidant is a mixture of hindered phenolic antioxidant and phosphite antioxidant at a weight ratio of 1-2:1.

[0018] According to some embodiments of the device of the present application, preferably, the filler is a terpolymer microsphere, preferably the filler is a maleic anhydride-styrene-alpha-methylstyrene terpolymer microsphere.

[0019] According to some embodiments of the device of the present application, preferably, the supercritical gas treatment temperature is 130-180℃, preferably 140-165℃.

[0020] According to some embodiments of the device of the present application, preferably, the supercritical gas treatment pressure is 1.0-25.0MPa, preferably 7.3-15.0MPa.

[0021] According to some embodiments of the device of the present application, preferably, the impregnation time is 1 minute to 1 hour, preferably 10-30 minutes.

[0022] According to some embodiments of the device of the present application, it can be a one-time pressure relief, with a pressure relief speed of 0.1-30MPa / min, preferably 1-10MPa / min. It can also be a multiple segmented pressure relief. Each segment has a pressure relief speed of 1-30MPa / min, preferably 3-15MPa / min.

[0023] According to some embodiments of the device of the present application, the low-oxygen reactor is provided with an anoxic zone and an aerobic zone, and the volume ratio of the anoxic zone to the aerobic zone is 1:2-1:5.

[0024] According to some embodiments of the device of the present application, the interior of the autotrophic denitrification filter further comprises a supporting layer, i.e. the interior of the autotrophic denitrification filter comprises a supporting layer and a filler layer, the bottom is a supporting layer, and the supporting layer is filled with gravel, and the filler layer is filled with denitrification filler.

[0025] According to some embodiments of the device of the present application, the particle size of the gravel is 8-15mm, and the height is 10-50cm.

[0026] According to some embodiments of the device of the present application, the volume ratio of the denitrification filler is 50-80%.

[0027] According to some embodiments of the device of the present application, the denitrification filler comprises FeS, elemental sulfur and an active component, the active component being Zn and / or Ti, more preferably, the weight ratio of FeS to elemental sulfur is 0.5-1:1, and the active component is added in an amount of 0.1-0.5% by weight of the total weight of the denitrification filler.

[0028] According to some embodiments of the device of the present application, the average particle size of the denitrification filler is 1-5mm, preferably 2-3.5mm, and the specific surface area is 300-1000m 2 / g.

[0029] According to some embodiments of the device of the present application, a stirring device is arranged in the coagulation sedimentation tank.

[0030] According to some embodiments of the device of the present application, the effluent of the coagulation sedimentation tank is connected to the bottom inlet of the UASB reactor by a pipeline.

[0031] According to some embodiments of the device of the present application, the wastewater treatment device is used for treating wastewater from a waste resource utilization process, wherein the pH of the wastewater is 7-9, the COD is 50000-800000mg / L, the TN is 100-800mg / L, and the ammonia nitrogen is 100-800mg / L. The main organic pollutants in the wastewater include benzene series, methanol, esters, etc.

[0032] According to some specific embodiments of the device of the present application, the wastewater treatment device mainly comprises a coagulation sedimentation tank 1, a UASB reactor 2, a low-oxygen reactor 3, a high-efficiency sedimentation tank 4, and an autotrophic denitrification filter 5 connected in sequence. The wastewater is fed into the coagulation sedimentation tank 1, which is provided with a stirring device. The effluent of the coagulation sedimentation tank 1 is connected to the bottom inlet of the UASB reactor by a pipeline. The effluent of the UASB reactor is connected to the inlet of the low-oxygen reactor 3 by a pipeline. The effluent of the low-oxygen reactor 3 is connected to the inlet of the high-efficiency sedimentation tank 4 by a pipeline. The outlet of the high-efficiency sedimentation tank 4 is connected to the inlet of the autotrophic denitrification filter 5 by a pipeline. The effluent of the autotrophic denitrification filter 5 meets the discharge standard.

[0033] The second aspect of the present application provides a wastewater treatment process, comprising: sequentially passing the wastewater through a coagulation sedimentation tank, a UASB reactor, a low-oxygen reactor, an efficient sedimentation tank and an autotrophic denitrification filter tank, wherein coagulation and sedimentation are performed in the coagulation sedimentation tank to remove heavy metals and part of organic matters attached to suspended solids in the wastewater; the UASB reactor is filled with granular sludge and functional carriers and performs anaerobic reaction to remove high-concentration organic matters in the wastewater and decompose refractory organic matters into small-molecule organic matters; the low-oxygen reactor performs anoxic / aerobic biochemical reaction to remove organic matters, ammonia nitrogen and total nitrogen in the wastewater; the efficient sedimentation tank performs sludge sedimentation; and the autotrophic denitrification filter tank is filled with denitrification fillers in the filler layer and performs autotrophic reaction to remove total nitrogen in the wastewater.

[0034] According to some embodiments of the process of the present application, in order to remove suspended solids and heavy metal pollutants in the wastewater and reduce their adverse effects on biochemical reaction, the waste polyester resourceization process wastewater is first sent to the coagulation sedimentation tank, and coagulation reagents are added to remove suspended solids, heavy metals and part of organic matters, with a hydraulic retention time of 0.5-2h.

[0035] According to some embodiments of the process of the present application, the coagulation reagents are added in the coagulation sedimentation tank, wherein the coagulation reagents comprise a flocculant and a coagulant aid.

[0036] According to some embodiments of the process of the present application, preferably, the flocculant is PFS.

[0037] According to some embodiments of the process of the present application, preferably, the amount of PFS is added at 30-150mg per liter of wastewater, more preferably, the amount of PFS is added at 50-100mg per liter of wastewater.

[0038] According to some embodiments of the process of the present application, preferably, the coagulant aid is cationic PAM.

[0039] According to some embodiments of the process of the present application, preferably, the amount of PAM is added at 1-15mg per liter of wastewater, more preferably, the amount of PAM is added at 3-10mg per liter of wastewater.

[0040] According to some embodiments of the process of the present application, the COD volume loading in the UASB reactor is 5-40kg / m 3 ·d, and the hydraulic retention time is 10-30h.

[0041] According to some embodiments of the process of the present application, the filling ratio of the functional carrier in the UASB reactor is 5-20% by volume. After coagulation and sedimentation, the wastewater is sent to the UASB reactor for high-efficiency anaerobic reaction. The UASB reactor is filled with functional carriers, and the filling ratio is 5-20% by volume. The COD volume load in the UASB reactor is 5-40 kg / m 3 The UASB reactor performs high-efficiency anaerobic reaction under the action of granular sludge. Due to the impact of the incoming water, the granular sludge is easily disintegrated, resulting in a decrease in particle size and a decrease in sludge volume in the reactor. Therefore, light functional carriers are added to the reactor to maintain the properties of the granular sludge and to proliferate it to obtain a high sludge retention concentration, allowing the reactor to operate well under high load conditions. In addition, the granular sludge formed in the reactor has a high microbial density and excellent settling performance, making it easy to separate solids from liquids. The water density of the functional carrier is 1.0-1.1 kg / L, which is easy to fluidize. After biofilm formation, the upward flow rate is 10-40 m / h, the biological mass transfer is good, and the anaerobic biochemical load is high.

[0042] According to some embodiments of the process of the present application, the method for preparing the functional carrier comprises: mixing one or more polyolefin resins with an antioxidant and a filler, then feeding them into an extrusion molding machine, and drawing the strip through a pelletizer to obtain granules; drying the granules and feeding them into a supercritical fluid treatment device to control the process temperature, pressure, immersion time, pressure release rate, and other conditions to obtain a functional carrier with high surface roughness and to regulate the apparent density, pore structure, and specific surface area of the functional carrier.

[0043] According to some embodiments of the process of the present application, preferably, the weight of the antioxidant is 0.05-1 parts based on 100 parts of the polyolefin resin, and the weight of the filler is 0.5-30 parts.

[0044] According to some embodiments of the process of the present application, preferably, the polyolefin resin is selected from one or more of polypropylene, polyethylene, polybutylene, and polyamylene. For example, but not limited to: polyethylene resin, homopolymer polypropylene T30s, LDPE LD100AC, high melt strength polypropylene HMS20Z, LD100AC, etc.

[0045] According to some embodiments of the process of the present application, the antioxidant can be any antioxidant commonly used in the art. Preferably, the antioxidant is a mixture of a hindered phenolic antioxidant and a phosphite antioxidant in a weight ratio of 1-2:1.

[0046] According to some embodiments of the process of the present application, preferably, the filler is a terpolymer microsphere, preferably, the filler is a maleic anhydride-styrene-alpha-methylstyrene terpolymer microsphere.

[0047] According to some embodiments of the process of the present application, preferably, the supercritical gas treatment temperature is 130-180℃, preferably 140-165℃.

[0048] According to some embodiments of the process of the present application, preferably, the supercritical gas treatment pressure is 1.0-25.0MPa, preferably 7.3-15.0MPa.

[0049] According to some embodiments of the process of the present application, preferably, the impregnation time is 1 minute-1 hour, preferably 10-30 minutes.

[0050] According to some embodiments of the process of the present application, the pressure relief can be one-time, with a pressure relief speed of 0.1-30MPa / min, preferably 1-10MPa / min. Alternatively, the pressure relief can be multiple segmented, with each segment having a pressure relief speed of 1-30MPa / min, preferably 3-15MPa / min.

[0051] According to some embodiments of the process of the present application, the low-oxygen reactor has an anoxic zone and an aerobic zone, with a volume ratio of the anoxic zone to the aerobic zone being 1:2-1:5, the DO in the anoxic zone being controlled at 0-0.5mg / L, and the DO in the aerobic zone being controlled at 0.7-1.5mg / L. The effluent from the UASB reactor is sent to the low-oxygen reactor, which can effectively remove the organic matter in the wastewater and effectively remove the ammonia nitrogen and total nitrogen in the wastewater through nitrification and denitrification reactions.

[0052] According to some embodiments of the process of the present application, the low-oxygen reactor uses a new type of micro-bubble aerator, with a bubble diameter of 10-30μm. Under this condition, the oxygen solubility can be effectively increased. The process can save 40% of the aeration amount compared to the conventional activated sludge method.

[0053] According to some embodiments of the process of the present application, the low-oxygen reactor has a return flow of 100-500%. On one hand, this can effectively dilute the pollutants in the incoming water, avoiding the influence of water quality fluctuations on the biochemical reaction; on the other hand, this is conducive to mass transfer, improving the biochemical reaction rate. The low-oxygen reactor effectively removes organic matter, ammonia nitrogen and total nitrogen, with the effluent COD being less than 100mg / L, the effluent ammonia nitrogen being less than 10mg / L, and the total nitrogen being less than 50mg / L.

[0054] According to some embodiments of the process of the present application, the low-oxygen reactor effluent is sent to a high-efficiency sedimentation tank, and after sludge settlement, to an autotrophic denitrification filter tank, which effectively removes the remaining total nitrogen in the wastewater by autotrophic denitrification without adding additional carbon source, and can achieve discharge standard.

[0055] According to some embodiments of the process of the present application, the autotrophic denitrification filter tank further comprises a supporting layer, and the filter material of the supporting layer is gravel. That is, the autotrophic denitrification filter tank comprises a supporting layer and a filler layer, wherein the filter material of the supporting layer is gravel, and the filler layer is filled with denitrification filler.

[0056] According to some embodiments of the process of the present application, the particle size of the gravel is 8-15 mm, and the height is 10-50 cm.

[0057] According to some embodiments of the process of the present application, the volume ratio of the denitrification filler is 50-80%.

[0058] According to some embodiments of the process of the present application, the denitrification filler comprises FeS, elemental sulfur and an active component, the active component is Zn and / or Ti, more preferably, the weight ratio of FeS to elemental sulfur is 0.5-1:1, and the addition amount of the active component is 0.1-0.5% by weight of the total weight of the denitrification filler.

[0059] According to some embodiments of the process of the present application, the average particle size of the denitrification filler is 1-5 mm, preferably 2-3.5 mm, and the specific surface area is 300-1000 m 2 / g.

[0060] According to some embodiments of the process of the present application, the coagulation sedimentation tank is provided with a stirring device.

[0061] According to some embodiments of the process of the present application, the effluent of the coagulation sedimentation tank is connected to the bottom inlet of the UASB reactor by a pipeline.

[0062] According to some embodiments of the process of the present application, the wastewater treatment device is used for treating wastewater from a waste resource utilization process, wherein the pH of the wastewater is 7-9, the COD is 50000-800000 mg / L, the TN is 100-800 mg / L, and the ammonia nitrogen is 100-800 mg / L. The main organic pollutants in the wastewater include benzene series, methanol, esters, etc.

[0063] According to some embodiments of the process of the present application, the waste polyester recycling process wastewater enters the coagulation sedimentation tank through the water inlet pipeline, coagulation and sedimentation are performed to remove heavy metals and part of organic matters attached to suspended solids in the wastewater; after coagulation and sedimentation, the wastewater is sent to the UASB reactor for anaerobic reaction to remove high-concentration organic matters in the wastewater and decompose refractory organic matters into small-molecule organic matters; the effluent from the UASB reactor enters the low-oxygen reactor, and the organic matter, ammonia nitrogen and total nitrogen in the wastewater are removed through anoxic / aerobic biochemical reaction; after further sludge settling, the effluent from the low-oxygen reactor is sent to the autotrophic denitrification filter tank for autotrophic reaction to remove total nitrogen, so that the wastewater can be discharged in compliance with the standard.

[0064] The present application has the following advantages:

[0065] (1) The present application can realize efficient removal of pollutants such as characteristic organic matter, ammonia nitrogen and total nitrogen for waste polyester recycling process wastewater.

[0066] (2) The UASB reactor of the present application uses light functional carriers, and the formed granular sludge is compact and easy to suspend and fluidize, the treatment of organic matter load is high, the tolerance to incoming water impact is good, and the methane produced by anaerobic reaction can be recycled and utilized.

[0067] (3) The low-oxygen reactor of the present application has small footprint, low oxygen consumption and high utilization rate, and can realize efficient removal of organic matter, ammonia nitrogen and total nitrogen in the same structure.

[0068] (4) The autotrophic denitrification filter tank of the present application can realize total nitrogen removal without additional carbon source, the denitrification filler of the present application is easy to biofilm, the autotrophic denitrification efficiency is high, and the total nitrogen can be efficiently removed.

[0069] (5) The device and process of the present application can remove heavy metals and part of organic matters attached to suspended solids in the wastewater through coagulation and sedimentation. After coagulation and sedimentation, the wastewater is sent to the UASB reactor, light functional carriers are added to effectively improve the mechanical strength of anaerobic granular sludge and the treatment load of pollutants. The low-oxygen reactor is used to realize efficient removal of organic matter, ammonia nitrogen and total nitrogen in the integrated facility, the oxygen consumption is low and the utilization rate is high. The autotrophic denitrification filter tank filled with denitrification filler can realize total nitrogen removal without additional carbon source, the denitrification filler of the present application is easy to biofilm, the autotrophic denitrification efficiency is high, and the total nitrogen can be efficiently removed.

[0070] (6) The process of the present application has short reaction process and simplified device structure, which can reduce the investment cost and operation cost of the reaction device. BRIEF DESCRIPTION OF DRAWINGS

[0071] Figure 1 The present application provides a waste polyester recycling process wastewater treatment device.

[0072] Explanation of reference numerals in the attached figures

[0073] 1. Coagulation sedimentation tank; 2. UASB reactor; 3. Low oxygen reactor; 4. High-efficiency sedimentation tank; 5. Autotrophic denitrification filter. Detailed Implementation

[0074] To make the present invention easier to understand, the present invention will be described in detail below with reference to embodiments. These embodiments are for illustrative purposes only and are not limited to the scope of application of the present invention.

[0075] The testing method and equipment used in this invention are as follows:

[0076]

Example 1

[0077] Adopting such Figure 1 The wastewater treatment device shown is for the recycling of waste textiles. The device consists of a coagulation sedimentation tank 1, a UASB reactor 2, a low-oxygen reactor 3, a high-efficiency sedimentation tank 4, and an autotrophic denitrification filter 5, connected sequentially by pipelines. The coagulation sedimentation tank 1 is used for coagulation and sedimentation to remove heavy metals and some organic matter attached to suspended solids in the wastewater. The UASB reactor 2 is filled with granular sludge and functional carriers for anaerobic reaction to remove high concentrations of organic matter in the wastewater and decompose recalcitrant organic matter into smaller molecules. The low-oxygen reactor 3 is used for anoxic / aerobic biochemical reaction to remove organic matter, ammonia nitrogen, and total nitrogen from the wastewater. The high-efficiency sedimentation tank 4 is used for sludge settling. The autotrophic denitrification filter 5 is filled with denitrifying packing material for autotrophic reaction to remove total nitrogen from the wastewater.

[0078] The coagulation sedimentation tank 1 is equipped with a stirring device; the effluent from the coagulation sedimentation tank 1 is connected to the bottom inlet of the UASB reactor 2 via a pipeline. The low-oxygen reactor 3 is equipped with anoxic and aerobic zones; the autotrophic denitrification filter 5 also includes a support layer, wherein the filter media of the support layer is gravel.

[0079]

Example 2

[0080] Wastewater was treated using the wastewater treatment device described in Example 1. The wastewater was from the waste polyester resource recovery process, with a pH of 8.2, COD of 8300 mg / L, TN of 450 mg / L, and ammonia nitrogen of 330 mg / L. The reactor process parameters are as follows:

[0081] (1) Wastewater from the waste polyester resource utilization process is sent to a coagulation sedimentation tank, where PFS concentration is 90 mg / L, PAM concentration is 10 mg / L, and hydraulic retention time is 1 hour to remove suspended solids, heavy metals and some organic matter from the wastewater.

[0082] (2) The coagulation and sedimentation of the wastewater is sent to the UASB reactor for high-efficiency anaerobic reaction, the functional carrier filling ratio in the UASB is 10% by volume, the hydraulic retention time is 12h, the COD volume load is 8kg / m 3 ·d, the produced methane can be recycled.

[0083] The water-containing density of the functional carrier is 1.03kg / L, the upflow velocity after biofilm formation is 15m / h, the carrier is polyethylene resin, the weight is 100 parts; the antioxidant is a mixture of hindered phenolic antioxidant and phosphite antioxidant at a mass ratio of 1:1, the weight is 0.06 parts; the filler is maleic anhydride-styrene-alpha-methylstyrene ternary copolymer beads, the weight is 2.5 parts. After extrusion granulation, the supercritical fluid treatment device is heated to 145℃, the above particles are put into it, and the furnace cavity is sealed. Nitrogen gas with a pressure of 10MPa is introduced into the furnace cavity, so that the supercritical carbon dioxide diffuses into the matrix under the condition of 145℃ and 10MPa. After saturation for 20min, the diffusion equilibrium is reached, the pressure in the furnace cavity is reduced to 4MPa within 2min through a pressure relief valve, then the furnace cavity is opened to release pressure and foam, and is cooled and shaped to obtain the functional carrier. The carrier has a rough appearance, a large number of pores can be observed on the cross section, the average particle size is 1.0mm, the specific surface area is 32.68m 2 / g, and the apparent density is 0.60g / cm 3 .

[0084] (3) The effluent of the UASB reactor is sent to the low-oxygen reactor, the volume ratio of the anoxic zone to the aerobic zone is 1:2, the DO in the anoxic zone is controlled at 0-0.3mg / L, the DO in the aerobic zone is controlled at 0.7-1.1mg / L, the backflow amount is 200%, and the hydraulic retention time is 23h, so as to effectively remove the ammonia nitrogen and total nitrogen in the wastewater.

[0085] (4) The effluent of the low-oxygen reactor is sent to the high-efficiency sedimentation tank, and after the sludge is settled, it is sent to the autotrophic denitrification filter tank, the autotrophic denitrification filter tank is provided with a supporting layer and a filler layer, the filter material of the supporting layer is gravel, the particle size of the gravel is 8mm, and the height is 15cm, the volume ratio of the filler layer is 60%, the filler layer is filled with denitrification filler, the weight ratio of FeS to elemental sulfur in the denitrification filler is 1:1, the active Ti component is added by 0.2% by weight, the average particle size is 3.5mm, and the specific surface area is 500m 2 / g.

[0086] Specifically, after the above-mentioned treatment, the effluent COD is 79mg / L, the effluent ammonia nitrogen is 4.5mg / L, and the total nitrogen is 28.3mg / L, which can be discharged up to the standard.

[0087]

Example 3

[0088] The wastewater treatment device of Example 1 was used to treat wastewater, and the wastewater was waste polyester resourceization process wastewater with pH of 7.4, COD of 43,000 mg / L, TN of 470 mg / L, and ammonia nitrogen of 450 mg / L. The reactor process parameter range was as follows:

[0089] (1) The waste polyester resourceization process wastewater was fed into a coagulation sedimentation tank, PFS was added at a concentration of 70 mg / L, PAM was added at a concentration of 4 mg / L, and the hydraulic retention time was 1.5 h, so as to remove suspended solids, heavy metals, and part of organic matter in the wastewater.

[0090] (2) The wastewater after coagulation and sedimentation was fed into a UASB reactor for efficient anaerobic reaction, the functional carrier filling ratio in the UASB was 13% by volume, the hydraulic retention time was 15 h, the COD volumetric loading was 10 kg / m 3 ·d, and the generated methane could be recycled.

[0091] The water-containing density of the functional carrier was 1.01 kg / L, the upflowing speed after biofilm formation was 40 m / h, the carrier used was homopolymer polypropylene T30s, the weight was 100 parts; the antioxidant was a mixture of a hindered phenolic antioxidant and a phosphite antioxidant at a mass ratio of 1:1, the weight was 0.3 parts; the filler used was a maleic anhydride-styrene-alpha-methylstyrene ternary copolymer small ball, the weight was 15 parts. After extrusion granulation, the supercritical fluid treatment device was heated to 145°C, the above-mentioned particles were put into the device, and the furnace cavity was sealed. Nitrogen gas at 10 MPa was introduced into the furnace cavity, so that supercritical carbon dioxide diffused into the matrix at 160°C and 15 MPa. After saturation for 15 min, diffusion equilibrium was reached, the pressure in the furnace cavity was reduced to 7 MPa within 1 min through a pressure relief valve, the pressure was kept for 10 min, then the pressure was reduced to 3 MPa within 4 min, and then the furnace cavity was opened to release pressure and foam, and was cooled and shaped to obtain the functional carrier. The carrier had a rough appearance, a large number of pores could be observed on the cross section, the average particle size was 1.2 mm, the specific surface area was 27.27 m 2 / g, and the apparent density was 0.74 g / cm 3 .

[0092] (3) The effluent of the UASB reactor was fed into a low-oxygen reactor, the volume ratio of the anoxic zone to the aerobic zone was 1:3, the DO in the anoxic zone was controlled at 0-0.4 mg / L, the DO in the aerobic zone was controlled at 0.7-1.3 mg / L, the backflow amount was 300%, and the hydraulic retention time was 25 h, so as to effectively remove ammonia nitrogen and total nitrogen in the wastewater.

[0093] (4) The low-oxygen reactor effluent is sent to an efficient sedimentation tank, and after sludge settlement, it is sent to an autotrophic denitrification filter tank. A supporting layer and a filler layer are arranged in the autotrophic denitrification filter tank. The filter material of the supporting layer is gravel, the particle size of the gravel is 8 mm, and the height is 16 cm. The volume ratio of the filler layer is 60%, and the filler layer is filled with denitrification filler. The weight ratio of FeS to elemental sulfur in the denitrification filler is 0.6:1, and the active Ti component is added by 0.3% by weight. The average particle size is 2.0 mm, and the specific surface area is 900 m 2 / g.

[0094] Specifically, after the above-mentioned treatment, the effluent COD is 75 mg / L, the effluent ammonia nitrogen is 4.2 mg / L, and the total nitrogen is 29.6 mg / L, which can be discharged up to standard.

[0095]

Example 4

[0096] The wastewater treatment device of Example 1 is used for wastewater treatment. The wastewater is waste polyester resourceization process wastewater with pH of 8.1, COD of 240000 mg / L, TN of 580 mg / L, and ammonia nitrogen of 540 mg / L. The reactor process parameter range is as follows:

[0097] (1) The waste polyester resourceization process wastewater is sent to a coagulation sedimentation tank, and PFS with a concentration of 85 mg / L and PAM with a concentration of 5 mg / L are added. The hydraulic retention time is 0.9 h, and suspended solids, heavy metals and part of organic matter in the wastewater are removed.

[0098] (2) The wastewater after coagulation and sedimentation is sent to a UASB reactor for efficient anaerobic reaction. The functional carrier filling ratio in the UASB is 15% by volume, the hydraulic retention time is 15 h, and the COD volumetric loading is 20 kg / m 3 ·d. The generated methane can be recycled.

[0099] The water-containing density of the functional carrier is 1.04 kg / L, and the ascending flow rate after biofilm formation is 20 m / h. The carrier uses LDPE LD100AC, and the weight is 100 parts. The antioxidant is a mixture of a hindered phenolic antioxidant and a phosphite antioxidant in a mass ratio of 1:1, and the weight is 0.3 parts. The filler uses maleic anhydride-styrene-alpha-methyl styrene ternary copolymer beads, and the weight is 5 parts. After extrusion granulation, the supercritical fluid treatment device is heated to 140℃, the above-mentioned particles are placed in it, and the furnace cavity is sealed. Carbon dioxide with a pressure of 7.5 MPa is introduced into the furnace cavity, and the supercritical carbon dioxide diffuses into the matrix under the condition of 140℃ and 7.5 MPa. After saturation for 20 min, the diffusion equilibrium is reached, then the furnace cavity is opened for pressure relief and foaming, and the functional carrier is obtained after cooling and setting. The carrier has a rough appearance, a large number of pores can be observed on the cross section, the average particle size is 2.6 mm, the specific surface area is 43.19 m 2 / g, and the apparent density is 0.50 g / cm3 .

[0100] (3) The effluent of the UASB reactor is sent to the low-oxygen reactor, the volume ratio of the anoxic zone to the aerobic zone is 1:4, the DO in the anoxic zone is controlled at 0-0.5 mg / L, the DO in the aerobic zone is controlled at 0.7-1.5 mg / L, the return flow is 400%, and the hydraulic retention time is 25 h, so as to effectively remove the ammonia nitrogen and total nitrogen in the wastewater.

[0101] (4) The effluent of the low-oxygen reactor is sent to the high-efficiency sedimentation tank, and after sludge settlement, it is sent to the autotrophic denitrification filter tank, a supporting layer and a filler layer are arranged in the autotrophic denitrification filter tank, the filter material of the supporting layer is gravel, the particle size of the gravel is 9 mm, and the height is 25 cm, the volume ratio of the filler layer is 70%, the filler layer is filled with denitrification filler, the weight ratio of FeS to elemental sulfur in the denitrification filler is 0.7:1, the active Zn component is added by 0.2% by weight, the Ti component is added by 0.1% by weight, the average particle size is 3.0 mm, and the specific surface area is 700 m 2 / g.

[0102] Specifically, after the above-mentioned steps of treatment, the effluent COD is 78 mg / L, the effluent ammonia nitrogen is 4.4 mg / L, and the total nitrogen is 27.8 mg / L, which can be discharged up to standard.

[0103]

Example 5

[0104] The wastewater treatment device of Example 1 is used for wastewater treatment, and the wastewater is waste polyester resourceization process wastewater with pH of 7.9, COD of 520000 mg / L, TN of 630 mg / L, and ammonia nitrogen of 610 mg / L. The reactor process parameter range is as follows:

[0105] (1) The waste polyester resourceization process wastewater is sent to the coagulation sedimentation tank, PFS with a concentration of 95 mg / L and PAM with a concentration of 7 mg / L are added, the hydraulic retention time is 1.5 h, and the suspended solids, heavy metals and part of the organic matter in the wastewater are removed.

[0106] (2) The wastewater after coagulation and sedimentation is sent to the UASB reactor for efficient anaerobic reaction, the functional carrier filling ratio in the UASB is 20% by volume, the hydraulic retention time is 25 h, the COD volumetric loading is 30 kg / m 3 ·d, and the generated methane can be recycled.

[0107] The water content density of the functional carrier is 1.06 kg / L, the upflow velocity after biofilm formation is 20 m / h, the carrier adopts high melt strength polypropylene HMS20Z, and the weight is 100 parts; the antioxidant is a mixture of hindered phenolic antioxidant and phosphite antioxidant at a mass ratio of 1:1, and the weight is 0.3 parts; the filler adopts maleic anhydride-styrene-alpha-methylstyrene ternary copolymer beads, and the weight is 8 parts. After extrusion granulation, the supercritical fluid treatment device is heated to 163℃, the above particles are put into it, and the furnace cavity is sealed. Nitrogen at 15 MPa is introduced into the furnace cavity to make supercritical carbon dioxide diffuse into the matrix at 163℃ and 15 MPa. After 15 minutes of saturation, the diffusion equilibrium is reached, the pressure in the furnace cavity is reduced to 6 MPa within 3 minutes through the pressure relief valve, and then the furnace cavity is opened to release pressure and foam, and is cooled and shaped to obtain the functional carrier. The carrier has a rough appearance, a large number of pores can be observed on the cross section, the average particle size is 2.1 mm, the specific surface area is 59.35 m 2 / g, and the apparent density is 0.69 g / cm 3 .

[0108] (3) The effluent of the UASB reactor is sent to the low-oxygen reactor, the volume ratio of the anoxic zone to the aerobic zone is 1:5, the DO in the anoxic zone is controlled at 0-0.4 mg / L, the DO in the aerobic zone is controlled at 0.7-1.4 mg / L, the return flow is 350%, and the hydraulic retention time is 25 h, which effectively removes ammonia nitrogen and total nitrogen in the wastewater.

[0109] (4) The effluent of the low-oxygen reactor is sent to the high-efficiency sedimentation tank, and after sludge settlement, it is sent to the autotrophic denitrification filter tank. A supporting layer and a filler layer are arranged in the autotrophic denitrification filter tank. The filter material of the supporting layer is gravel, the particle size of the gravel is 10 mm, and the height is 30 cm. The volume ratio of the filler layer is 75%, and the filler layer is filled with denitrification filler. The weight ratio of FeS to elemental sulfur in the denitrification filler is 0.8:1, the active Zn component is added by 0.2% by weight, the average particle size is 3.3 mm, and the specific surface area is 600 m 2 / g.

[0110] Specifically, after the above treatment, the effluent COD is 78 mg / L, the effluent ammonia nitrogen is 4.6 mg / L, and the total nitrogen is 28.4 mg / L, which can be discharged up to standard.

[0111]

Example 6

[0112] The wastewater treatment device of Example 1 is used for wastewater treatment. The wastewater is waste polyester resourceization process wastewater, the pH is 8.6, the COD is 790000 mg / L, the TN is 780 mg / L, and the ammonia nitrogen is 720 mg / L. The reactor process parameter range is as follows:

[0113] (1) The waste and old polyester resource utilization process wastewater is sent to a coagulation sedimentation tank, PFS with a concentration of 100 mg / L and PAM with a concentration of 9 mg / L are added, and the hydraulic retention time is 1.3 h, so as to remove suspended solids, heavy metals and part of organic matter in the wastewater.

[0114] (2) The wastewater after coagulation and sedimentation is sent to a UASB reactor for efficient anaerobic reaction, the functional carrier filling ratio in the UASB is 10% by volume, the hydraulic retention time is 30 h, the COD volume load is 38 kg / m 3 ·d, and the generated methane can be recycled.

[0115] The water-containing density of the functional carrier is 1.09 kg / L, the upflowing speed after biofilm formation is 10 m / h, the carrier uses LD100AC, the weight is 100 parts; the antioxidant is a hindered phenolic antioxidant and a phosphite antioxidant mixed at a mass ratio of 2:1, the weight is 0.03 parts; the filler uses maleic anhydride-styrene-alpha-methylstyrene ternary copolymer beads, the weight is 25 parts. After extrusion granulation, the supercritical fluid treatment device is heated to 158℃, the above-mentioned particles are put into the device, and the furnace cavity is sealed. Nitrogen with a pressure of 8 MPa is introduced into the furnace cavity, so that supercritical carbon dioxide diffuses into the matrix under the condition of 158℃ and 8 MPa. After saturation for 30 min, the diffusion equilibrium is reached, the pressure in the furnace cavity is reduced to 4 MPa within 2.5 min through a pressure relief valve, then the furnace cavity is opened to release pressure and foaming, and is cooled and shaped to obtain the functional carrier. The carrier has a rough appearance, a large number of pores can be observed on the cross section, the average particle size is 0.9 mm, the specific surface area is 48.09 m 2 / g, and the apparent density is 0.55 g / cm 3 .

[0116] (3) The effluent of the UASB reactor is sent to a low-oxygen reactor, the volume ratio of the anoxic zone to the aerobic zone is 1:3, the DO in the anoxic zone is controlled at 0-0.3 mg / L, the DO in the aerobic zone is controlled at 0.7-1.2 mg / L, the backflow amount is 250%, and the hydraulic retention time is 30 h, so as to effectively remove ammonia nitrogen and total nitrogen in the wastewater.

[0117] (4) The effluent of the low-oxygen reactor is sent to an efficient sedimentation tank, and after sludge settlement, it is sent to an autotrophic denitrification filter tank, a supporting layer and a filler layer are arranged in the autotrophic denitrification filter tank, the filter material of the supporting layer is gravel, the particle size of the gravel is 10 mm, and the height is 25 cm, the volume ratio of the filler layer is 80%, the filler layer is filled with denitrification filler, the weight ratio of FeS to elemental sulfur in the denitrification filler is 0.9:1, the active Zn component is added by 0.3% by weight, the average particle size is 4.5 mm, and the specific surface area is 500 m 2 / g.

[0118] Specifically, after the above steps, the effluent COD is 76 mg / L, the effluent ammonia nitrogen is 4.7 mg / L, and the total nitrogen is 28.9 mg / L, which can be discharged up to standard.

[0119] Comparative Example 1

[0120] The pH of the waste polyester resourceization process wastewater is 8.2, the COD is 83000 mg / L, the TN is 450 mg / L, and the ammonia nitrogen is 330 mg / L. The same process as in Example 1 is used for treatment, but the anaerobic reactor is replaced by an anaerobic acidification and hydrolysis device, the COD volume load of the anaerobic acidification and hydrolysis device is 3 kg / m 3 ·d.

[0121] Specifically, after the above steps, the effluent COD is 152 mg / L, the effluent ammonia nitrogen is 12.2 mg / L, and the total nitrogen is 41.3 mg / L.

[0122] Comparative Example 2

[0123] The pH of the waste polyester resourceization process wastewater is 8.2, the COD is 83000 mg / L, the TN is 450 mg / L, and the ammonia nitrogen is 330 mg / L. The same UASB device as in Example 1 is used for treatment, but the UASB reactor has no filler (i.e. a conventional UASB reactor), and the COD volume load of the UASB reactor is 6 kg / m 3 ·d.

[0124] Specifically, after the above steps, the effluent COD is 143.5 mg / L, the effluent ammonia nitrogen is 14.3 mg / L, and the total nitrogen is 45.6 mg / L.

[0125] Comparative Example 3

[0126] The pH of the waste polyester resourceization process wastewater is 8.2, the COD is 83000 mg / L, the TN is 450 mg / L, and the ammonia nitrogen is 330 mg / L. The same device as in Example 1 is used for treatment, the low-oxygen reactor is replaced by a normal aerobic reactor, the oxygen consumption is increased by 50%, and only ammonia nitrogen can be removed, total nitrogen cannot be removed, the effluent ammonia nitrogen is 25 mg / L, and the total nitrogen is 150 mg / L.

[0127] Specifically, after the above steps, the effluent COD is 171 mg / L, the effluent ammonia nitrogen is 14.6 mg / L, and the total nitrogen is 79.6 mg / L.

[0128] Comparative Example 4

[0129] The pH of the waste polyester resource utilization process wastewater is 8.2, the COD is 83000 mg / L, the TN is 450 mg / L, and the ammonia nitrogen is 330 mg / L. The same device as in Example 1 is used for treatment, but the denitrification is a common heterotrophic denitrification filter, and the consumption of organic carbon source is greatly increased, and the effluent COD cannot meet the discharge standard.

[0130] Specifically, after the above-mentioned steps, the effluent COD is 152 mg / L, the effluent ammonia nitrogen is 26.2 mg / L, and the total nitrogen is 49.5 mg / L.

[0131] The above-mentioned is only the preferred example of the present application. It should be noted that for those skilled in the art, under the technical inspiration provided by the present application, as the common knowledge in the art, other equivalent variants and improvements can also be made, which should also be considered as the protection scope of the present application.

Claims

1. A wastewater treatment device for waste textile recycling processes, comprising a coagulation sedimentation tank, a UASB reactor, a low-oxygen reactor, a high-efficiency sedimentation tank, and an autotrophic denitrification filter connected sequentially by pipelines, wherein, The coagulation sedimentation tank is used for coagulation and sedimentation to remove heavy metals and some organic matter attached to suspended solids in wastewater. The UASB reactor is filled with granular sludge and functional carriers for anaerobic reaction to remove high concentrations of organic matter in wastewater and decompose recalcitrant organic matter into small molecule organic matter. The low-oxygen reactor is used to carry out anoxic / aerobic biochemical reactions to remove organic matter, ammonia nitrogen and total nitrogen from wastewater; the low-oxygen reactor is equipped with anoxic zone and aerobic zone, and the volume ratio of the anoxic zone to the aerobic zone is 1:2-1:

5. The high-efficiency sedimentation tank is used for sludge settling. The packing layer of the autotrophic denitrification filter is filled with denitrification packing for autotrophic reaction to remove total nitrogen from wastewater; The functional carrier comprises 100 parts by weight of polyolefin resin, 0.05-1 parts by weight of antioxidant, and 0.5-30 parts by weight of filler. The polyolefin resin is selected from one or more of polypropylene, polyethylene, polybutene, and polypentene. The antioxidant is a mixture of hindered phenolic antioxidant and phosphite antioxidant in a weight ratio of 1-2:

1. The filler is maleic anhydride-styrene-α-methylstyrene terpolymer microspheres.

2. The wastewater treatment device for waste textile recycling processes according to claim 1, characterized in that, The functional carriers packed in the UASB reactor are 5-20% of the volume.

3. The wastewater treatment device for waste textile recycling processes according to claim 1, characterized in that, The average particle size of the functional carrier is 0.5-2.5 mm; the specific surface area is 1-100 m². 2 / g; apparent density is 0.20-0.80 g / cm³ 3 The water content density is 1.0-1.1 kg / L, and the upward flow velocity after biofilm formation is 10-40 m / h.

4. The wastewater treatment device for waste textile recycling processes according to claim 3, characterized in that, The functional carrier has an average particle size of 0.7-1.5 mm and a specific surface area of ​​10-60 m². 2 / g, apparent density is 0.45-0.75g / cm³ 3 .

5. The wastewater treatment device for the recycling process of waste textiles according to any one of claims 1-4, characterized in that, The interior of the autotrophic denitrification filter also includes a support layer, the filter media of which is gravel.

6. The wastewater treatment device for waste textile recycling process according to claim 5, characterized in that, The gravel has a particle size of 8-15 mm and a height of 10-50 cm; and / or The denitrification packing has a volume ratio of 50-80%, and / or The denitrification packing material comprises FeS, elemental sulfur, and an active component, wherein the active component is Zn and / or Ti, and / or The denitrification packing has an average particle size of 1-5 mm and a specific surface area of ​​300-1000 m². 2 / g.

7. The wastewater treatment device for waste textile recycling process according to claim 6, characterized in that, In the denitrification packing, the weight ratio of FeS to elemental sulfur is 0.5-1:1, the amount of active component added is 0.1-0.5% by weight of the total weight of the denitrification packing; and / or, the average particle size of the denitrification packing is 2-3.5 mm.

8. The wastewater treatment device for the recycling process of waste textiles according to any one of claims 1-4, characterized in that, The coagulation sedimentation tank is equipped with a stirring device; and / or, the effluent from the coagulation sedimentation tank is connected to the bottom inlet of the UASB reactor via a pipeline.

9. The wastewater treatment device for the recycling process of waste textiles according to any one of claims 1-4, characterized in that, The wastewater treatment device is used to treat wastewater from the recycling process of waste textiles, wherein the wastewater has a pH of 7-9, a COD of 50,000-800,000 mg / L, a TN of 100-800 mg / L, and an ammonia nitrogen of 100-800 mg / L.

10. A method for treating waste textile recycling process wastewater in the waste textile recycling process wastewater treatment device according to any one of claims 1-9, characterized in that, include: Wastewater is sequentially passed through a coagulation sedimentation tank, a UASB reactor, a low-oxygen reactor, a high-efficiency sedimentation tank, and an autotrophic denitrification filter. In the coagulation sedimentation tank, coagulation and sedimentation occur to remove heavy metals and some organic matter attached to suspended solids. In the UASB reactor, granular sludge and functional carriers are packed and an anaerobic reaction occurs to remove high concentrations of organic matter and decompose recalcitrant organic matter into smaller molecules. In the low-oxygen reactor, an anoxic / aerobic biochemical reaction occurs to remove organic matter, ammonia nitrogen, and total nitrogen from the wastewater. Sludge settles in the high-efficiency sedimentation tank. Finally, in the autotrophic denitrification filter, denitrifying packing is packed into the packing layer and an autotrophic reaction occurs to remove total nitrogen from the wastewater.

11. The method for treating wastewater from the recycling process of waste textiles according to claim 10, characterized in that, Coagulants are added to the coagulation sedimentation tank, wherein the coagulants include flocculants and coagulant aids.

12. The method for treating wastewater from the recycling process of waste textiles according to claim 11, characterized in that, The flocculant is PFS, and / or the coagulant aid is cationic PAM.

13. The method for treating wastewater from the recycling process of waste textiles according to claim 12, characterized in that, PFS is added at a dosage of 30-150 mg per liter of wastewater, and / or PAM is added at a dosage of 1-15 mg per liter of wastewater.

14. The method for treating wastewater from the recycling process of waste textiles according to claim 12, characterized in that, PFS is added at a dosage of 50-100 mg per liter of wastewater; and / or PAM is added at a dosage of 3-10 mg per liter of wastewater.

15. The method for treating wastewater from the recycling process of waste textiles according to any one of claims 10-14, characterized in that, The COD volumetric loading in the UASB reactor is 5-40 kg / m³. 3 •d, hydraulic residence time 10-30h.

16. The method for treating wastewater from the recycling process of waste textiles according to any one of claims 10-14, characterized in that, In the hypoxic zone, the dissolved oxygen (DO) should be controlled at 0-0.5 mg / L, and in the aerobic zone, the DO should be controlled at 0.7-1.5 mg / L.

17. The method for treating wastewater from the recycling process of waste textiles according to claim 10, characterized in that, The low-oxygen reactor employs a microbubble aerator with bubble diameters of 10-30 μm; and / or The reflux rate of the low-oxygen reactor is 100-500%.

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