A papermaking wastewater treatment system

Abstract

The utility model relates to papermaking wastewater treatment technical field, more particularly, relate to a kind of papermaking wastewater treatment system. Papermaking wastewater treatment system includes adjusting device, hydrolytic acidification device, UASB reaction device, aerobic device, pH control device, flocculation formation device, filter device and COD separation device;Adjusting device is connected with hydrolytic acidification device, hydrolytic acidification device is connected with UASB reaction device, UASB reaction device is connected with aerobic device, aerobic device is connected with pH control device, pH control device is connected with flocculation formation device, flocculation formation device is connected with filter device, filter device is connected with COD separation device, and COD separation device is connected with filter device. The utility model papermaking wastewater treatment system structure composition is simple, with efficient, low consumption, the green processing technical advantage of resource.

Description

Technical Field

[0001] This utility model relates to the field of papermaking wastewater treatment technology, and more specifically, to a papermaking wastewater treatment system. Background Technology

[0002] The papermaking process mainly includes three major steps: pulping, bleaching, and papermaking. The wastewater produced by different processes has significantly different characteristics. Pulping is further divided into chemical pulping, mechanical pulping, and waste paper pulping. The papermaking process generates wastewater with characteristics such as high organic matter, high suspended solids, high hardness, high alkalinity, and deep color. This wastewater cannot be directly discharged and is difficult to treat.

[0003] Chinese patent application number 202522074541.0 discloses a papermaking wastewater treatment system. This system produces low-standard water after anaerobic, aerobic, and Fenton deep treatment of papermaking wastewater. The water produced by this system cannot be directly entered into the reclaimed water system.

[0004] Chinese patent application number 201010117708.7 discloses a wastewater reuse treatment system and method for straw pulp papermaking wastewater. This system and method involves coagulation sedimentation, ultrafiltration, reverse osmosis, and ozone deep treatment of the wastewater, with the produced water reused and the concentrated wastewater meeting industry discharge standards. However, this system is not suitable for papermaking wastewater with high COD and high hardness.

[0005] Currently, the mainstream treatment process for this wastewater is "physicochemical pretreatment + anaerobic / aerobic biochemical treatment + advanced treatment (Fenton or ozone advanced oxidation)". This process has disadvantages such as high initial investment, high operating costs, long process route and complex and difficult-to-control operation. Utility Model Content

[0006] To address the problem that existing water treatment systems are ineffective when papermaking wastewater exhibits high COD and high hardness, this invention provides a papermaking wastewater treatment system, comprising:

[0007] Adjustment device, hydrolysis acidification device, UASB reaction device, aerobic device, pH control device, floc forming device, filtration device and COD separation device;

[0008] The outlet of the regulating device is connected to the inlet of the hydrolysis acidification device, the outlet of the hydrolysis acidification device is connected to the inlet of the UASB reactor, the outlet of the UASB reactor is connected to the inlet of the aerobic device, the outlet of the aerobic device is connected to the inlet of the pH control device, the outlet of the pH control device is connected to the inlet of the floc forming device, the outlet of the floc forming device is connected to the inlet of the filtration device, the inlet of the filtration device is connected to the outlet of the COD separation device, and the inlet of the COD separation device is connected to the inlet of the filtration device.

[0009] According to one embodiment of the present invention, the regulating device includes a hydrolysis acidification tank and a first booster pump. The inlet of the hydrolysis acidification tank is connected to the outlet of the regulating device through a first pipe, the outlet of the hydrolysis acidification tank is connected to the first booster pump through a second pipe, and the first booster pump is connected to the inlet of the UASB reactor through a third pipe.

[0010] According to one embodiment of the present invention, the aerobic device includes an aerobic tank and a sedimentation tank. The outlet of the UASB reactor is connected to the inlet of the aerobic tank through a fourth pipe, the outlet of the aerobic tank is connected to the sedimentation tank through a fifth pipe, and the outlet of the sedimentation tank is connected to the pH control device through a sixth pipe.

[0011] According to one embodiment of the present invention, the pH control device is connected to a dosing reaction tank, an alkaline dosing unit, a softening dosing unit, and a second booster pump. The inlet of the dosing reaction tank is connected to the pH control device through a sixth pipe, the outlet of the dosing reaction tank is connected to the second booster pump through a seventh pipe, the second booster pump is connected to the inlet of the floc forming device through an eighth pipe, the alkaline dosing unit is connected to the first inlet of the dosing reaction tank through a ninth pipe, and the softening dosing unit is connected to the first inlet of the dosing reaction tank in parallel with the ninth pipe through a tenth pipe.

[0012] According to one embodiment of the present invention, the floc forming device includes a mixing pipe, a PAC dosing unit, and a PAM dosing unit. The mixing pipe is connected to the second booster pump through the eighth pipe, the outlet of the mixing pipe is connected to the inlet of the filter device through the eleventh pipe, the PAC dosing unit is connected to the second dosing port of the mixing pipe through the twelfth pipe, and the PAM dosing unit is connected to the mixing pipe in parallel with the twelfth pipe through the thirteenth pipe.

[0013] According to one embodiment of the present invention, the second dosing port is located near the water inlet of the mixing pipe.

[0014] According to one embodiment of the present invention, the filtration device includes a first filtration unit and a second filtration unit. The first filtration unit is connected to the mixing pipe through an eleventh pipe, the second filtration unit is connected to the first filtration unit through a fourteenth pipe, and the second filtration unit is connected to the COD separation device through a fifteenth pipe.

[0015] According to one embodiment of the present invention, a sludge treatment device is also included. The sludge treatment device includes a plate and frame filter press and a sludge collection tank. The sludge collection tank is connected to the plate and frame filter press through a 20th pipe. The sludge outlet of the UASB reactor is connected to the sludge collection tank through a 21st pipe. The sludge outlet of the sedimentation tank is connected to the sludge collection tank through a 22nd pipe. The sludge outlet of the first filtration unit is connected to the sludge collection tank through a 23rd pipe.

[0016] According to one embodiment of the present invention, the regulating device includes a regulating tank and a fifth lift pump. The inlet of the hydrolysis acidification device is connected to the fifth lift pump through the first pipe, and the fifth lift pump is connected to the outlet of the regulating tank through the twenty-fourth pipe.

[0017] According to one embodiment of the present invention, the mixing pipe is provided with baffles arranged at intervals, and a medium channel is formed between the baffles and the mixing pipe.

[0018] The present invention has the following beneficial effects:

[0019] This utility model papermaking wastewater treatment system features low initial investment, low operating costs, simple structure, and stable operation. It is an efficient, low-consumption, and resource-efficient green treatment technology with broad application prospects.

[0020] After treatment of papermaking wastewater using the papermaking wastewater treatment system of this utility model, the final effluent has COD≤30mg / L, total hardness≤160mg / L, SO4≤680mg / L, Cl≤700mg / L, TDS≤4500mg / L, and color≤40 degrees.

[0021] This invention, through the combination of an alkaline dosing unit and a softening and dosing unit, can reduce fouling and clogging of the subsequent membrane system, reduce the cleaning frequency of the membrane system, and reduce the replacement frequency of the filter bags in the filtration unit.

[0022] The desalination rate of this novel COD membrane separation device is about 8%, indicating that it does not cause salt enrichment. The color removal rate is about 84%, and the COD removal rate is about 73%, achieving efficient removal of COD from papermaking wastewater. Attached Figure Description

[0023] Figure 1 A schematic diagram of a papermaking wastewater treatment system according to one embodiment is shown.

[0024] Figure reference numerals: 10-Regulating device; 11-Regulating tank; 12-Fifth lift pump; 14-Twenty-fourth pipeline; 20-Hydrolysis acidification device; 21-Hydrolysis acidification tank; 22-First lift pump; 23-First pipeline; 24-Second pipeline; 25-Third pipeline; 30-UASB reactor; 40-Aerobic device; 41-Aerobic tank; 42-Sedimentation tank; 43-Fourth pipeline; 44-Fifth pipeline; 45-Sixth pipeline; 50-pH control device; 51-Dosing reaction tank; 52-Alkaline dosing unit; 53-Softening dosing unit; 54-Second lift pump; 55-Seventh pipeline; 56-Eighth pipeline; 57-Ninth pipeline; 58-Tenth pipeline; 60-Floc forming device; 61-Mixing pipeline; 62-PAC unit; 63-PAM unit; 64-Eleventh Pipeline; 65-Twelfth Pipeline; 66-Thirteenth Pipeline; 67-Baffle Plate; 70-Filtration Device; 71-First Filtration Unit; 711-Filter; 712-First Reservoir; 713-Third Booster Pump; 72-Second Filtration Unit; 721-Ultrafiltration Unit; 722-Second Reservoir; 723-Fourth Booster Pump; 73-Fourteenth Pipeline; 74-Fifteenth Pipeline; 75-Sixteenth Pipeline; 76-Seventeenth Pipeline; 77-Eighteenth Pipeline; 78-Nineteenth Pipeline; 80-COD Separation Device; 90-Reclaimed Water Reuse Tank; 100-Sludge Treatment Device; 101-Plate and Frame Filter Press; 102-Sludge Collection Tank; 103-Twentieth Pipeline; 104-Twenty-first Pipeline; 105-Twenty-second Pipeline; 106-Twenty-third Pipeline. Detailed Implementation

[0025] The present disclosure will now be discussed with reference to several exemplary embodiments. It should be understood that these embodiments are discussed only to enable those skilled in the art to better understand and thus implement the present disclosure, and are not intended to imply any limitation on the scope of the disclosure.

[0026] As used herein, the term "comprising" and its variations are to be interpreted as open-ended terms meaning "including but not limited to". The term "based on" is to be interpreted as "at least partially based on". The terms "one embodiment" and "an embodiment" are to be interpreted as "at least one embodiment". The term "another embodiment" is to be interpreted as "at least one other embodiment". The terms "upper", "lower", "left", "right", "front", "rear", "top", "bottom", "inner", "outer", "vertical", "horizontal", "lateral", "longitudinal", etc., indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings. These terms are primarily for the purpose of better describing this application and its embodiments and are not intended to limit the indicated devices, elements, or components to having a specific orientation or being constructed and operated in a specific orientation. Furthermore, some of the above terms may be used to indicate other meanings besides orientations or positional relationships; for example, the term "upper" may in some cases indicate a dependency or connection relationship. Those skilled in the art can understand the specific meaning of these terms in this application according to the specific circumstances. In addition, the terms "installed", "set up", "equipped with", "connected", and "linked" should be interpreted broadly. For example, it can be a fixed connection, a detachable connection, or an integral structure; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or an internal connection between two devices, elements, or components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances. Furthermore, the terms "first," "second," etc., are mainly used to distinguish different devices, elements, or components (the specific types and structures may be the same or different), and are not used to indicate or imply the relative importance or quantity of the indicated devices, elements, or components. Unless otherwise stated, "a plurality of" means two or more.

[0027] This embodiment discloses a papermaking wastewater treatment system, such as Figure 1 As shown, it may include:

[0028] Adjustment device 10, hydrolysis acidification device 20, UASB reaction device 30, aerobic device 40, pH control device 50, floc forming device, filtration device 70 and COD separation device 80;

[0029] The outlet of the regulating device 10 is connected to the inlet of the hydrolysis acidification device 20. The outlet of the hydrolysis acidification device 20 is connected to the inlet of the UASB reaction device 30. The outlet of the UASB reaction device 30 is connected to the inlet of the aerobic device 40. The outlet of the aerobic device 40 is connected to the inlet of the pH control device 50. The outlet of the pH control device 50 is connected to the inlet of the floc forming device. The outlet of the floc forming device is connected to the inlet of the filtration device 70. The inlet of the filtration device 70 is connected to the outlet of the COD separation device 80. The inlet of the COD separation device 80 is connected to the inlet of the filtration device 70.

[0030] In this embodiment, when the papermaking wastewater treatment system treats the papermaking wastewater, the water quality characteristics of the treated wastewater are: pH 6~8, COD 4000mg / L, total hardness 3300mg / L, SO4 1000mg / L, Cl 700mg / L, TDS 4000mg / L, and color 210 degrees.

[0031] The papermaking wastewater of the above-mentioned quality enters the equalization device 10 for homogenization of water quality and quantity. The permeate from the equalization device 10 enters the hydrolysis acidification device 20. In the hydrolysis acidification device 20, the recalcitrant large molecular organic matter in the wastewater is broken down and converted into easily degradable small molecular organic matter, thereby greatly improving the biodegradability of the wastewater and facilitating subsequent treatment. The effluent COD can reach 1800 mg / L. The permeate from the hydrolysis acidification device 20 enters the UASB reactor. After anaerobic digestion in the UASB reactor 30, the organic matter (COD) in the wastewater is efficiently removed, so that the COD of the effluent from the UASB reactor 30 can reach 700 mg / L. The permeate from the UASB reactor 30 enters the aerobic device 40. Under aerobic conditions, the aerobic device 40 uses aerobic microorganisms (mainly aerobic bacteria and nitrifying bacteria) to further degrade and stabilize the pollutants in the wastewater. The effluent COD can reach 150 mg / L. The permeate from the aerobic device 40 enters the pH control device. The wastewater is treated by a pH control device 50, which adjusts the pH of the wastewater to 10-11 and then softens it. The wastewater from the pH control device 50 enters a floc forming device 60. After the floc forming device 60 fully mixes and reacts the wastewater, the wastewater from the floc forming device 60 enters a filtration device 70. The filtration device 70 filters the wastewater, and the COD of the wastewater from the filtration device 70 is 110 mg / L, and the color is 150 degrees. The wastewater from the filtration device 70 enters a COD separation device 80. The COD separation device 80 performs COD membrane separation on the wastewater, so that the wastewater from the COD separation device 80 has a COD ≤ 30 mg / L, total hardness ≤ 160 mg / L, SO4 ≤ 680 mg / L, Cl ≤ 700 mg / L, TDS ≤ 4500 mg / L, and color ≤ 40 degrees. The wastewater from the COD membrane separation device meets the influent standards of the greywater reuse system and enters a greywater reuse tank 90. This embodiment of the papermaking wastewater treatment system improves the quality of treated effluent and achieves resource regeneration.

[0032] According to one embodiment of the present invention, such as Figure 1 As shown, the regulating device 10 includes a hydrolysis acidification tank 21 and a first lift pump 22. The inlet of the hydrolysis acidification tank 21 is connected to the outlet of the regulating device 10 through a first pipe 23. The outlet of the hydrolysis acidification tank 21 is connected to the first lift pump 22 through a second pipe 24. The first lift pump 22 is connected to the inlet of the UASB reactor 30 through a third pipe 25.

[0033] In this embodiment, the first booster pump 22 is used to send water from the hydrolysis acidification tank 21 into the UASB reactor 30.

[0034] According to one embodiment of the present invention, such as Figure 1As shown, the aerobic device 40 includes an aerobic tank 41 and a sedimentation tank 42. The outlet of the UASB reactor 30 is connected to the inlet of the aerobic tank 41 through a fourth pipe 43. The outlet of the aerobic tank 41 is connected to the sedimentation tank 42 through a fifth pipe 44. The outlet of the sedimentation tank 42 is connected to the pH control device 50 through a sixth pipe 45.

[0035] In this embodiment, the aerobic tank 41 biodegrades the UASB permeate. After biodegradation, the water in the aerobic tank 41 flows into the sedimentation tank 42 through the fifth pipe 44. The water undergoes solid-liquid separation in the sedimentation tank 42, and the supernatant after separation is sent to the pH control device 50 through the sixth pipe 45.

[0036] According to one embodiment of the present invention, such as Figure 1 As shown, the pH control device 50 is connected to a dosing reaction tank 51, an alkaline dosing unit 52, a softening dosing unit 53, and a second booster pump 54. The inlet of the dosing reaction tank 51 is connected to the pH control device 50 through the sixth pipe 45, and the outlet of the dosing reaction tank 51 is connected to the second booster pump 54 through the seventh pipe 55. The second booster pump 54 is connected to the inlet of the floc forming device through the seventh pipe 56. The alkaline dosing unit 52 is connected to the first inlet of the dosing reaction tank 51 through the ninth pipe 57, and the softening dosing unit 53 is connected to the first inlet of the dosing reaction tank 51 in parallel with the ninth pipe 57 through the tenth pipe 58.

[0037] In this embodiment, the dosing reaction tank 51 supplies water to react with the reagents. After the sedimentation tank 42 supplies water to the dosing reaction tank 51, alkaline reagents are added to the dosing reaction tank 51 through the alkaline dosing unit 52 to make the pH of the water in the dosing reaction tank 51 10~11. Then, softening reagents are added through the softening dosing unit 53 to soften the water in the dosing reaction tank 51. Then, the softened water in the dosing reaction tank 51 is sent to the floc forming device 60 through the second lift pump 54.

[0038] In some embodiments, alkaline agents include, but are not limited to, sodium hydroxide.

[0039] Preferably, the alkaline dosing unit 52 is a sodium hydroxide dosing unit.

[0040] In some embodiments, the softening agent includes, but is not limited to, sodium carbonate.

[0041] Preferably, the softening dosing unit 53 is a sodium carbonate dosing unit.

[0042] According to one embodiment of the present invention, such as Figure 1As shown, the floc forming device includes a mixing pipe 61, a PAC dosing unit, and a PAM dosing unit. The mixing pipe 61 is connected to the second booster pump 54 via the seventh pipe 56. The outlet of the mixing pipe 61 is connected to the inlet of the filter device 70 via the eleventh pipe 64. The PAC dosing unit is connected to the second dosing port of the mixing pipe 61 via the twelfth pipe 65. The PAM dosing unit is connected to the mixing pipe 61 in parallel with the twelfth pipe 65 via the thirteenth pipe 66.

[0043] In this embodiment, the second booster pump 54 delivers the softened water from the dosing reaction tank 51 to the mixing pipe, and provides PAC and PAM agents to the mixing pipe through the PAC dosing unit and the PAM dosing unit, respectively. The water mixes with the PAC and PAM agents in the mixing pipe, further promoting the separation of impurities from the water.

[0044] PAC stands for polyaluminum chloride, and PAM stands for polyacrylamide.

[0045] According to one embodiment of the present invention, such as Figure 1 As shown, the second dosing port is located near the inlet of the mixing pipe 61.

[0046] In this embodiment, by placing the second dosing port near the inlet of the mixing pipe 61, more contact opportunities are provided between the water and the PAC and PAM agents.

[0047] According to one embodiment of the present invention, such as Figure 1 As shown, the filtration device 70 includes a first filtration unit 71 and a second filtration unit 72. The first filtration unit 71 is connected to the mixing pipe 61 through an eleventh pipe 64, and the second filtration unit 72 is connected to the first filtration unit 71 through a fourteenth pipe 73. The second filtration unit 72 is connected to the COD separation device 80 through a fifteenth pipe 74.

[0048] In this embodiment, water is mixed with PAC and PAM agents in mixing pipe 61 and then enters the first filtration unit 71 for filtration, resulting in a total hardness of 200 mg / L and a color of 190 degrees for the water produced by the first filtration unit 71. The water produced by the first filtration unit 71 then enters the second filtration unit 72, where the water is further filtered. In the second filtration unit 72, physical sieving and removal of suspended solids, colloids, bacteria, viruses, and macromolecular organic matter are carried out. The water produced by the second filtration unit 72 has a COD of 110 mg / L and a color of 150 degrees. The water produced by the second filtration unit 72 then enters the second filtration unit.

[0049] In some embodiments, the first filtration unit 71 includes a filter 711, a first water storage tank 712, and a third lift pump 713. The inlet of the filter 711 is connected to the outlet of the mixing pipe 61 through the eleventh pipe 64, the outlet of the filter 711 is connected to the first water storage tank 712 through the fourteenth pipe 73, and the first water storage tank 712 is connected to the third lift pump 713 through the fifteenth pipe 74.

[0050] The second filtration unit 72 includes an ultrafilter 721, a second water storage tank 722, and a fourth booster pump 723. The third booster pump 713 is connected to the inlet of the ultrafilter 721 through a sixteenth pipe 75. The outlet of the ultrafilter 721 is connected to the second water storage tank 722 through a seventeenth pipe 76. The second water storage tank 722 is connected to the fourth booster pump 723 through an eighteenth pipe 77. The fourth booster pump 723 is connected to the inlet of the COD separation device 80 through a nineteenth pipe 78.

[0051] In some embodiments, the filtration accuracy of filter 711 is less than that of ultrafilter 721.

[0052] According to one embodiment of the present invention, such as Figure 1 As shown, it also includes a sludge treatment device 100, which includes a plate and frame filter press 101 and a sludge collection tank 102. The sludge collection tank is connected to the plate and frame filter press 101 through a twentieth pipe 103. The sludge outlet of the UASB reactor 30 is connected to the sludge collection tank 102 through a twenty-first pipe 104. The sludge outlet of the sedimentation tank 42 is connected to the sludge collection tank 102 through a twenty-second pipe. The sludge outlet of the first filtration unit 71 is connected to the sludge collection tank 102 through a twenty-third pipe.

[0053] In this embodiment, the sludge treatment device 100 allows the sludge produced by the UASB reactor 30, sedimentation tank 42 and filter 711 to enter the sludge collection tank 102, thereby dewatering the sludge in the sludge collection tank 102 by the plate and frame filter press 101, and achieving further water recovery.

[0054] Preferably, the plate and frame filter press 101 is a high-pressure diaphragm filter press.

[0055] According to one embodiment of the present invention, such as Figure 1 As shown, the regulating device 10 includes a regulating tank 11 and a fifth lift pump 12. The inlet of the hydrolysis acidification device 20 is connected to the fifth lift pump 12 through a first pipe 23, and the fifth lift pump 12 is connected to the outlet of the regulating tank 11 through a twenty-fourth pipe 13.

[0056] In this embodiment, the fifth booster pump 12 facilitates the delivery of water from the equalization tank 11 to the hydrolysis acidification device 20.

[0057] According to one embodiment of the present invention, such as Figure 1 As shown, the mixing pipe 61 is provided with baffles 67 arranged at intervals inside, and a medium channel is formed between the baffles 67 and the mixing pipe 61.

[0058] In this embodiment, by setting the baffle 67, the reaction time between water and PAC and PAM reagents is increased, allowing water to fully react with PAC and PAM reagents, thereby further improving the separation effect between water and impurities.

[0059] Those skilled in the art will understand that the above embodiments are specific examples of implementing this disclosure, and in practical applications, various changes can be made in form and detail without departing from the scope of this disclosure.

Claims

1. A papermaking wastewater treatment system, characterized by, include: Adjustment device, hydrolysis acidification device, UASB reaction device, aerobic device, pH control device, floc forming device, filtration device and COD separation device; The outlet of the regulating device is connected to the inlet of the hydrolysis acidification device, the outlet of the hydrolysis acidification device is connected to the inlet of the UASB reactor, the outlet of the UASB reactor is connected to the inlet of the aerobic device, the outlet of the aerobic device is connected to the inlet of the pH control device, the outlet of the pH control device is connected to the inlet of the floc forming device, the outlet of the floc forming device is connected to the inlet of the filtration device, the inlet of the filtration device is connected to the outlet of the COD separation device, and the inlet of the COD separation device is connected to the inlet of the filtration device.

2. The papermaking wastewater treatment system according to claim 1, characterized in that, The hydrolysis acidification device includes a hydrolysis acidification tank and a first lift pump. The inlet of the hydrolysis acidification tank is connected to the outlet of the regulating device through a first pipe. The outlet of the hydrolysis acidification tank is connected to the first lift pump through a second pipe. The first lift pump is connected to the inlet of the UASB reactor through a third pipe.

3. A papermaking effluent treatment system according to claim 1 wherein, The aerobic device includes an aerobic tank and a sedimentation tank. The outlet of the UASB reactor is connected to the inlet of the aerobic tank via a fourth pipe. The outlet of the aerobic tank is connected to the sedimentation tank via a fifth pipe. The outlet of the sedimentation tank is connected to the pH control device via a sixth pipe.

4. A papermaking effluent treatment system according to claim 3 wherein, The pH control device is connected to a dosing reaction tank, an alkaline dosing unit, a softening dosing unit, and a second booster pump. The inlet of the dosing reaction tank is connected to the pH control device through the sixth pipe, and the outlet of the dosing reaction tank is connected to the second booster pump through the seventh pipe. The second booster pump is connected to the inlet of the floc forming device through the eighth pipe. The alkaline dosing unit is connected to the first inlet of the dosing reaction tank through the ninth pipe, and the softening dosing unit is connected to the first inlet of the dosing reaction tank in parallel with the ninth pipe through the tenth pipe.

5. The papermaking wastewater treatment system according to claim 4, characterized in that, The floc forming device includes a mixing pipe, a PAC dosing unit, and a PAM dosing unit. The mixing pipe is connected to the second booster pump through the eighth pipe. The outlet of the mixing pipe is connected to the inlet of the filter device through the eleventh pipe. The PAC dosing unit is connected to the second dosing port of the mixing pipe through the twelfth pipe. The PAM dosing unit is connected to the mixing pipe in parallel with the twelfth pipe through the thirteenth pipe.

6. The papermaking wastewater treatment system according to claim 5, characterized in that, The second dosing port is located near the inlet of the mixing pipe.

7. A papermaking effluent treatment system according to claim 6 wherein, The filtration device includes a first filtration unit and a second filtration unit. The first filtration unit is connected to the mixing pipe through an eleventh pipe, the second filtration unit is connected to the first filtration unit through a fourteenth pipe, and the second filtration unit is connected to the COD separation device through a fifteenth pipe.

8. A papermaking effluent treatment system according to claim 7 wherein, It also includes a sludge treatment device, which includes a plate and frame filter press and a sludge collection tank. The sludge collection tank is connected to the plate and frame filter press through a 20th pipe. The sludge outlet of the UASB reactor is connected to the sludge collection tank through a 21st pipe. The sludge outlet of the sedimentation tank is connected to the sludge collection tank through a 22nd pipe. The sludge outlet of the first filtration unit is connected to the sludge collection tank through a 23rd pipe.

9. A papermaking effluent treatment system according to claim 8 wherein, The regulating device includes a regulating tank and a fifth lift pump. The inlet of the hydrolysis acidification device is connected to the fifth lift pump through a first pipe, and the fifth lift pump is connected to the outlet of the regulating tank through a twenty-fourth pipe.

10. A papermaking effluent treatment system according to claim 5 wherein, The mixing pipe is equipped with baffles arranged at intervals, and a medium channel is formed between the baffles and the mixing pipe.

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