Tissue production wastewater treatment system

Abstract

The invention relates to the field of wastewater treatment, in particular to a tissue production wastewater treatment system which comprises a pretreatment tank for tissue wastewater to enter, an agent feeding pipe for feeding a flotation agent is fixedly connected to the bottom in the pretreatment tank, and a transfer tank for temporarily placing separated fibers is arranged on the periphery of the pretreatment tank. A circulating belt is arranged above the pretreatment tank and the transfer tank, the transmission surface of the circulating belt is detachably connected with a plurality of transfer hoppers, each transfer hopper can move to the position under the liquid level of the pretreatment tank and the position over the transfer tank so as to move fiber foam into the transfer tank, and the pretreatment tank is communicated with an ultrafiltration membrane assembly for separating residual fibers in wastewater. The ultrafiltration membrane assembly is communicated with a post-treatment tank for deeply treating and disinfecting the wastewater, so that fibers in the wastewater can be relatively comprehensively removed, and meanwhile, the fibers can be relatively efficiently separated from the wastewater.

Description

Technical Field

[0001] The present application relates to the field of wastewater treatment, and in particular to a wastewater treatment system for paper towel production. Background Art

[0002] During the production process of paper towels, a large amount of wastewater containing fibers is generated, which needs to be treated to meet the standards before being discharged. The biggest difference between paper towel wastewater treatment and other wastewater treatments is that a relatively large amount of fibers need to be separated and recovered to reduce the subsequent wastewater treatment pressure and improve the resource utilization rate.

[0003] Some existing paper towel wastewater treatments use a scraper to collect the fibers on the water surface first, and then, in order to collect the remaining fibers in the water, a flocculant needs to be added to form fiber flocs and precipitate the remaining fibers in the paper towel wastewater. For example, a pulp and water separation device for papermaking wastewater with the publication number CN110204099B.

[0004] Regarding the above related technologies, the scraper reciprocates to collect the fibers on the water surface, and the collection efficiency is slow, so that the fiber content in the wastewater entering the flocculation tank subsequently is still relatively high, and it is necessary to wait for a long time to fully flocculate a relatively large amount of fibers, and the overall fiber separation and recovery efficiency is low. Summary of the Invention

[0005] In order to improve the overall fiber separation and recovery efficiency, the present application provides a wastewater treatment system for paper towel production.

[0006] The wastewater treatment system for paper towel production provided by the present application adopts the following technical solutions.

[0007] A wastewater treatment system for paper towel production includes a pretreatment tank for paper towel wastewater to enter. A dosing pipe for feeding a flotation agent is fixedly connected to the bottom inside the pretreatment tank. There is a transfer tank around the pretreatment tank for temporarily placing the separated fibers. A circulating belt is provided above the pretreatment tank and the transfer tank. Several material transfer hoppers are detachably connected to the driving surface of the circulating belt. Each material transfer hopper can move to directly below the liquid level of the pretreatment tank and directly above the transfer tank to move the fiber foam into the transfer tank. The pretreatment tank is communicated with an ultrafiltration membrane module for separating the remaining fibers in the wastewater, and the ultrafiltration membrane module is communicated with a post-treatment tank for deeply treating and disinfecting the wastewater.

[0008] By adopting the above technical solutions, first, a flotation agent is added into the pretreatment tank to make as many fibers as possible float on the liquid surface of the pretreatment tank to form fiber foam, and the circulating belt continuously drives, so that the material transfer hoppers continuously transfer the fiber foam into the transfer tank. Then, the paper towel wastewater with a small amount of remaining fibers enters the ultrafiltration membrane module, so that the fibers in the paper towel wastewater can be fully separated, and the overall fiber separation efficiency is relatively high.

[0009] Optionally, the material transfer hopper includes a hopper body detachably connected to the surface of the circulating belt drive, and a sealing plate rotatably connected to the lower opening of the hopper body located directly below the circulating belt. The sealing plate can close or open the opening of the hopper body to allow the fiber to fall from the hopper body into the transfer pool.

[0010] By adopting the above technical solution, the fiber foam in the hopper body can be lowered into the transfer pool during the continuous transmission of the circulating belt.

[0011] Optionally, a worm gear is coaxially and fixedly connected to the rotation point of the sealing plate. The worm gear meshes with a worm. A side rack is detachably connected to the frame of the circulating belt at a position directly above the transfer pool. The side rack is used to drive the worm to rotate.

[0012] By adopting the above technical solution, the sealing plate is not easily rotated randomly, so that when the sealing plate needs to close the opening on one side of the hopper body, the fiber foam in the hopper body will not fall randomly.

[0013] Optionally, a middle gear is coaxially and fixedly connected to the end of the worm away from the sealing plate. The middle gear can mesh with the side rack.

[0014] By adopting the above technical solution, when the hopper body moves to a predetermined position, the middle gear will mesh with the side rack, and the middle gear is not easily immersed in the paper towel wastewater in the pretreatment pool.

[0015] Optionally, the rotation point of the sealing plate is located at the center point of its own surface so that the sealing plate can rotate 180° to re-close the hopper body.

[0016] By adopting the above technical solution, only one side rack with a sufficient length is needed to make the sealing plate rotate 180° and then re-close the hopper body, simplifying the structural setting.

[0017] Optionally, the sealing plate and the hopper body are both provided with liquid passing holes.

[0018] By adopting the above technical solution, the paper towel wastewater in the hopper body can be discharged in time during the process of the hopper body lifting a part of the fiber foam and moving upward along with the circulating belt.

[0019] Optionally, the pretreatment pool includes a front pool for the paper towel wastewater to enter and a rear pool connected to the ultrafiltration membrane module. An upper partition plate and a lower partition plate are fixedly connected between the front pool and the rear pool. The bottom height of the upper partition plate is lower than the top height of the lower partition plate. The upper partition plate is closer to the front pool than the lower partition plate. The bottom of the lower partition plate is fixedly connected to the inner bottom surface of the rear pool.

[0020] By adopting the above technical solution, larger volume particulate solids in the paper towel wastewater can be further prevented from entering the rear pool, so as to preliminarily treat the paper towel wastewater.

[0021] Optionally, the height of the top of the upper partition plate is lower than the liquid level height of the pretreatment tank. A pool-side pipe capable of sending out air flow is detachably connected to the periphery of the pretreatment tank, and the lowest point of the circulating belt is located at the center of all the pool-side pipes.

[0022] By adopting the above technical solution, the fiber foam on the liquid surface of the paper towel wastewater in the pretreatment tank can be gathered directly below the lowest point of the circulating belt, so that the bucket body can scoop up as much fiber foam as possible.

[0023] Optionally, a liquid distribution plate is detachably connected to the bottom of the pretreatment tank. The liquid distribution plate is provided with several liquid distribution holes in a penetrating manner, and all the liquid distribution holes communicate with the additive pipe.

[0024] By adopting the above technical solution, the flotation agent can be fully contacted with the paper towel wastewater in the pretreatment tank, so that as many fibers as possible in the paper towel wastewater float up to form fiber foam.

[0025] Optionally, the liquid distribution plate is also provided with several air holes, and all the air holes communicate with a floating pipe capable of sending in air flow. The diameter of the air holes is smaller than the diameter of the liquid distribution holes, and the position where the pretreatment tank communicates with the ultrafiltration membrane module is lower than the height of the liquid distribution plate.

[0026] By adopting the above technical solution, it is further enabled that the fibers in the paper towel wastewater can fully float up, and the paper towel wastewater has to enter the ultrafiltration membrane module through the air holes and the liquid distribution holes, further enabling the fibers in the paper towel wastewater to form fiber foam and float up.

[0027] In summary, the present application has at least the following beneficial effects.

[0028] First, a flotation agent is added to the pretreatment tank so that as many fibers as possible float on the liquid surface of the pretreatment tank to form fiber foam, and the circulating belt continuously drives, so that the transfer hopper continuously transfers the fiber foam to the transfer tank. Then, the paper towel wastewater with a small part of fibers enters the ultrafiltration membrane module, so that the fibers in the paper towel wastewater can be fully separated, and the overall fiber separation efficiency is relatively high. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 is a schematic diagram of the pipeline of the present application; Figure 2 is a schematic structural diagram of the cross-section of the pretreatment tank, the transfer tank and the protective shell, and the partial cross-section of the bucket body; Figure 3 is Figure 2 the enlarged view of part A in

[0030] Description of the reference numerals: 1. Pretreatment tank; 2. Additive pipe; 3. Transfer tank; 31. Protective shell; 4. Circulating belt; 41. Front tank; 42. Rear tank; 43. Upper partition board; 44. Lower partition board; 45. Pool side pipe; 46. Liquid distribution plate; 47. Liquid distribution holes; 48. Air holes; 49. Floating pipe; 5. Material transfer hopper; 51. Ultrafiltration membrane module; 52. Post-treatment tank; 53. Hopper body; 54. Sealing plate; 55. Worm gear; 56. Side rack; 57. Intermediate gear; 58. Worm; 59. Liquid passing holes. Detailed implementation manners

[0031] The present application will be further described in detail below with reference to the accompanying drawings.

[0032] An embodiment of the present application discloses a paper towel production wastewater treatment system. Referring to Figure 1 , it includes a pretreatment tank 1 connected by a communication pipeline for the entry of paper towel wastewater. The pretreatment tank 1 is connected with an additive pipe 2 that can connect an external centrifugal pump and a chemical agent barrel to feed a flotation agent, so that the fibers in the paper towel wastewater can form fiber foam and float as much as possible. There is a transfer tank 3 close to the periphery of the pretreatment tank 1. The transfer tank 3 is used for temporarily placing the fiber foam in the pretreatment tank 1 and waiting for a certain amount of fiber foam in the transfer tank 3 to be transferred and subjected to subsequent treatment. The pretreatment tank 1 is connected with an ultrafiltration membrane module 51 for filtering and separating the remaining fibers in the paper towel wastewater. The ultrafiltration membrane module 51 is connected with a post-treatment tank 52 that can remove some organic matters in the paper towel wastewater and disinfect them through a combination of methods such as activated carbon adsorption, ozone oxidation or chlorine addition.

[0033] Referring to Figure 2 and Figure 3 , a circulating belt 4 is detachably connected above the pretreatment tank 1 and the transfer tank 3. The circulating belt 4 is inclined, and the high end of the circulating belt 4 is located directly above the transfer tank 3, and the low end of the circulating belt 4 is located directly above the pretreatment tank 1. A plurality of material transfer hoppers 5 are evenly installed on the driving surface of the circulating belt 4. Each material transfer hopper 5 includes a hopper body 53 detachably connected to the driving surface of the circulating belt 4. The hopper body 53 forms two openings, one large and one small. The small opening of the hopper body 53 is far from the driving surface of the circulating belt 4. A sealing plate 54 is rotatably connected at the small opening of the hopper body 53. The rotation point of the sealing plate 54 is located at the center point of the surface of the sealing plate 54. Moreover, the hopper body 53 and the sealing plate 54 are both evenly provided with a plurality of liquid passing holes 59. The sealing plate 54 is coaxially and fixedly connected with a worm gear 55. The worm gear 55 meshes with a worm 58 rotatably connected to the outer wall of the hopper body 53. The length direction of the worm 58 is perpendicular to the driving surface of the circulating belt 4.

[0034] Referring to Figure 3, a middle gear 57 is coaxially and fixedly connected to the worm 58. The middle gear 57 is away from the worm gear 55 and close to the driving surface of the circulating belt 4, so that when the bucket body 53 moves to the lowest position of the circulating belt 4, the middle gear 57 is not easily immersed in the paper towel wastewater. Moreover, a protective shell 31 that encloses the worm gear 55 and the worm 58 is detachably and sealingly connected to the outer wall of the bucket body 53, and the middle gear 57 is exposed outside the protective shell 31. At the frame of the end of the circulating belt 4 with a higher height, a side rack 56 is detachably connected. The length direction of the side rack 56 is consistent with the inclination direction of the circulating belt 4. The side rack 56 can mesh with the middle gear 57, so that when the bucket body 53 moves directly above the transfer tank 3, the middle gear 57 meshes with the side rack 56, causing the sealing plate 54 to start rotating. After the sealing plate 54 rotates 180°, the middle gear 57 disengages from the side rack 56, completing the release of the fiber foam in the bucket body 53.

[0035] Referring to Figure 2 , the pretreatment tank 1 includes a front tank 41 and a rear tank 42. The upper part on the side of the front tank 41 away from the rear tank 42 is for the entry of paper towel wastewater. The bottom of the rear tank 42 is connected to the ultrafiltration membrane module 51. An upper partition plate 43 and a lower partition plate 44 are fixedly connected between the front tank 41 and the rear tank 42. The bottom height of the upper partition plate 43 is lower than the top height of the lower partition plate 44. The upper partition plate 43 is closer to the front tank 41 than the lower partition plate 44. The bottom of the lower partition plate 44 is fixedly connected to the inner bottom surface of the rear tank 42. The top height of the upper partition plate 43 is lower than the liquid level height of the pretreatment tank 1, so that when the upper partition plate 43 and the lower partition plate 44 effectively block the large-volume particulate matters in the paper towel wastewater, the upper partition plate 43 is not likely to block the fibers on the liquid surface of the front tank 41. Moreover, a pool-side pipe 45 is detachably connected to the periphery of the pretreatment tank 1. The pool-side pipe 45 is connected to an external blower so that the fiber foam on the liquid surface of the pretreatment tank 1 gathers directly below the lowest position of the circulating belt 4.

[0036] Referring to Figure 1 and Figure 2 , a liquid distribution plate 46 is fixedly connected to the inner bottom wall of the rear tank 42. The liquid distribution plate 46 is fixedly connected to the vertical surface of the lower partition plate 44 away from the upper partition plate 43. A plurality of liquid distribution holes 47 are uniformly perforated on the surface of the liquid distribution plate 46. Each liquid distribution hole 47 is connected to the additive pipe 2, so that the flotation agent can be fed into the paper towel wastewater from each liquid distribution hole 47. At the same time, a plurality of air holes 48 are also perforated on the liquid distribution plate 46. All the air holes 48 are connected to the same floating pipe 49. The floating pipe 49 is connected to an external blower so that air flows out of the air holes 48 to form bubbles. Moreover, the position where the pretreatment tank 1 is connected to the ultrafiltration membrane module 51 is lower than the height of the liquid distribution plate 46, so that the paper towel wastewater can only enter the ultrafiltration membrane module 51 after passing through the air holes 48 or the liquid distribution holes 47, minimizing the amount of fibers entering the ultrafiltration membrane module 51.

[0037] The implementation principle of a paper towel production wastewater treatment system according to an embodiment of the present application is as follows: The paper towel wastewater first enters the front pool 41 so that large-volume particulate matters are blocked by the upper partition plate 43 and the lower partition plate 44, and then the paper towel wastewater flows to the rear pool 42. The liquid distribution holes 47 send out the flotation agent and the air holes 48 send out compressed air so that the fibers float up to form fiber foam, and all the pool edge pipes 45 concentrate all the fiber foam to the lowest part of the circulation belt 4. Then the bucket body 53 scoops up the fiber foam and sends it into the transfer pool 3. Then the paper towel wastewater enters the ultrafiltration membrane module 51, and finally enters the post-treatment pool 52 to complete the advanced treatment and disinfection before being discharged.

[0038] The above are all preferred embodiments of the present application, and the protection scope of the present application is not limited thereby. Therefore, all equivalent changes made according to the structure, shape, and principle of the present application shall be covered within the protection scope of the present application.

Claims

1. A paper towel production wastewater treatment system, comprising a pretreatment tank (1) for paper towel wastewater to enter, characterized in that: The bottom of the pretreatment tank (1) is fixedly connected to a dosing pipe (2) for feeding a flotation agent. A transfer tank (3) is provided around the pretreatment tank (1) for temporarily placing separated fibers. A circulation belt (4) is provided above the pretreatment tank (1) and the transfer tank (3). A plurality of transfer hoppers (5) are detachably connected to the transmission surface of the circulation belt (4). Each transfer hopper (5) can be moved to a position just below the liquid surface of the pretreatment tank (1) and just above the transfer tank (3) to transfer fiber foam to the transfer tank (3). The pretreatment tank (1) is connected to an ultrafiltration membrane assembly (51) for separating residual fibers in wastewater. The ultrafiltration membrane assembly (51) is connected to a post-treatment tank (52) for deeply treating and disinfecting wastewater.

2. A paper towel production wastewater treatment system according to claim 1, characterized in that: The transfer hopper (5) comprises a hopper body (53) detachably connected to the transmission surface of the circulating belt (4), and a sealing plate (54) rotatably connected to the lower opening of the hopper body (53) located directly below the circulating belt (4); the sealing plate (54) can close or open the opening of the hopper body (53) to allow fibers to fall from the hopper body (53) into the transfer pool (3).

3. A paper towel production wastewater treatment system according to claim 2, characterized in that: A worm gear (55) is coaxially fixedly connected to the rotation point of the sealing plate (54), and a worm (58) is meshed with the worm gear (55). A rack of the circulating belt (4) is detachably connected to a side rack (56) located directly above the transfer pool (3), and the side rack (56) is used to drive the worm (58) to rotate.

4. A paper towel production wastewater treatment system according to claim 3, characterized in that: The worm (58) is coaxially fixedly connected to a middle gear (57) at one end away from the sealing plate (54), and the middle gear (57) can mesh with the side rack (56).

5. A paper towel production wastewater treatment system according to claim 3, characterized in that: The rotation point of the sealing plate (54) is located at the center point of its own surface so that the sealing plate (54) can re-seal the bucket body (53) by rotating 180 degrees.

6. A paper towel production wastewater treatment system according to claim 2, characterized in that: The sealing plate (54) and the bucket body (53) are both provided with a liquid passage hole (59) extending therethrough.

7. A paper towel production wastewater treatment system according to claim 1, characterized in that: The pretreatment tank (1) comprises a front tank (41) for paper towel wastewater to enter and a rear tank (42) connected to an ultrafiltration membrane assembly (51), an upper baffle (43) and a lower baffle (44) are fixedly connected between the front tank (41) and the rear tank (42), the bottom height of the upper baffle (43) is lower than the top height of the lower baffle (44), the upper baffle (43) is closer to the front tank (41) than the lower baffle (44), and the bottom of the lower baffle (44) is fixedly connected to the inner bottom surface of the rear tank (42).

8. A paper towel production wastewater treatment system according to claim 7, characterized in that: The top height of the upper baffle (43) is lower than the liquid level of the pretreatment pool (1). The periphery of the pretreatment pool (1) is detachably connected with a pool side pipe (45) capable of delivering airflow. The lowest point of the circulation belt (4) is located at the center of all the pool side pipes (45).

9. A paper towel production wastewater treatment system according to claim 1, characterized in that: A liquid distribution plate (46) is detachably connected to the bottom of the pretreatment tank (1), and a plurality of liquid distribution holes (47) are formed through the liquid distribution plate (46), and all the liquid distribution holes (47) are connected to the dosing pipe (2).

10. A paper towel production wastewater treatment system according to claim 9, characterized in that: The liquid distribution plate (46) is also provided with a plurality of air holes (48), all of which are connected to a floating tube (49) capable of delivering air flow, the diameter of the air hole (48) is smaller than the diameter of the liquid distribution hole (47), and the position at which the pretreatment tank (1) is connected to the ultrafiltration membrane assembly (51) is lower than the height of the liquid distribution plate (46).

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