A multi-stage sewage treatment system and process based on environment-friendly processing of plastic products

Abstract

The application relates to the technical field of sewage treatment, and discloses a sewage multistage treatment system and process based on plastic product environment-friendly processing, wherein the sewage multistage treatment system based on plastic product environment-friendly processing comprises a pretreatment unit, a flocculation unit, a filtering unit, a biodegradation unit and a deep treatment unit which are sequentially communicated through connecting pipes; the filtering unit comprises a filter cylinder arranged between the flocculation unit and the biodegradation unit, a filter plate adjusting assembly arranged in the filter cylinder, and a plurality of water guide cylinders arranged on the circumferential surface of the filter cylinder and communicated with the inside of the filter cylinder. The sewage is sequentially treated by the pretreatment unit, the flocculation unit, the filtering unit, the biodegradation unit and the deep treatment unit, so that the sewage reaches the discharge standard; the filtering unit adopts a dynamic filtering mechanism, ensures continuous and efficient sewage treatment, can more thoroughly remove pollutants, makes the discharged water reach the standard, reduces the damage to the water body ecology, and improves the environment-friendly effect of the plastic product processing industry.

Description

Technical Field

[0001] This invention relates to the field of wastewater treatment technology, and in particular to a multi-stage wastewater treatment system and process based on environmentally friendly processing of plastic products. Background Technology

[0002] Wastewater generated during the processing of plastic products has a complex composition. During production and processing, a large amount of industrial wastewater containing complex pollutants is generated, including not only coarse impurities and suspended particles, but also fine plastic particles, additives, oil stains and other colloidal and dissolved pollutants. Direct discharge will cause serious environmental pollution and is not conducive to environmental protection. At present, the industry generally adopts a multi-stage process of "pretreatment-flocculation-filtration-biodegradation-deep treatment", among which the filtration unit is the core link of wastewater filtration.

[0003] In existing technologies, when traditional filter plates become clogged due to the accumulation of flocculents and impurities, frequent shutdowns are required for manual cleaning, which cannot achieve automatic cleaning. This not only reduces treatment efficiency but also makes it difficult to maintain a stable filtration flow rate. In addition, most existing filtration devices are designed with fixed filter plates, which cannot be dynamically adjusted according to changes in wastewater pressure to adaptively balance the water pressure at the filter plates. This makes it difficult to balance filtration accuracy and cleaning efficiency, affecting the effectiveness of subsequent biodegradation and deep treatment, resulting in a low rate of wastewater discharge that meets standards.

[0004] Therefore, there is an urgent need for a multi-stage wastewater treatment system that can achieve automatic cleaning of filter plates, dynamic adjustment of filtration status, and is conducive to environmental protection, while ensuring continuous and stable treatment, in order to meet the wastewater treatment needs of environmentally friendly plastic product processing. Summary of the Invention

[0005] Given the problems of existing technologies, such as the clogging of traditional filtration devices due to impurity accumulation, requiring frequent shutdowns for manual cleaning and resulting in low treatment efficiency; and the inability to dynamically adjust the fixed filter plates according to sewage pressure, making it difficult to balance filtration accuracy and cleaning efficiency, which in turn affects the subsequent treatment effect, a multi-stage sewage treatment system based on the environmentally friendly processing of plastic products is proposed.

[0006] Its purpose is to solve the problems of traditional filtration devices, such as easy clogging, frequent shutdown for cleaning, low efficiency, and the inability of filter plates to dynamically move and adjust with pressure, as well as the imbalance between filtration accuracy and cleaning efficiency. It aims to achieve efficient and continuous treatment of wastewater from plastic product processing, improve filtration stability and subsequent treatment effects, and ensure that wastewater meets discharge standards.

[0007] The technical solution of the present invention is a multi-stage wastewater treatment system based on environmentally friendly processing of plastic products, including a pretreatment unit, a flocculation unit, a filtration unit, a biodegradation unit and a deep treatment unit connected in sequence by connecting pipes. The filtration unit includes a filter cylinder disposed between the flocculation unit and the biodegradation unit, a filter plate adjustment assembly disposed inside the filter cylinder, and several water guide cylinders disposed on the periphery of the filter cylinder and connected to its interior. The filter plate adjustment assembly includes a first filter plate and a second filter plate sequentially disposed inside the filter cylinder. The first filter plate is detachably installed inside the filter cylinder, and the second filter plate is located at the bottom of the first filter plate and slides between it and the filter cylinder. The filter plate adjustment assembly also includes a guide rod detachably connected to the first filter plate. The guide rod is fixedly connected to the filter cylinder by a connecting rod, and slides between the guide rod and the second filter plate. A scraper is slidably disposed on the periphery of the guide rod and fits against the second filter plate. The scraper is used to scrape off impurities and flocculents from the surface of the second filter plate when it moves along the guide rod. The pretreatment unit is used to remove coarse impurities and suspended particles from wastewater, the flocculation unit is used to remove colloidal and dissolved pollutants, the biodegradation unit is used to degrade organic pollutants, and the advanced treatment unit is used to remove residual pollutants.

[0008] Furthermore, the first filter plate has a first filter hole on its surface, and the second filter plate has a second filter hole on its surface, wherein the inner diameter of the first filter hole is larger than the inner diameter of the second filter hole.

[0009] Furthermore, a plurality of first sleeve rods are detachably installed at the bottom of the first filter plate. A first elastic element is fixedly provided at the bottom of the first sleeve rod. A connecting ring is fixedly provided at the bottom end of the first elastic element. A T-shaped plate is fixedly provided at the bottom of the connecting ring. A T-shaped groove that slides with the T-shaped plate is opened at the top of the second filter plate. A first sleeve corresponding to the first sleeve rod is fixedly provided at the top of the connecting ring. The first sleeve is sleeved and connected to the corresponding first sleeve rod.

[0010] Furthermore, a triangular push plate is symmetrically fixedly arranged at the bottom of the second filter plate, and a limiting opening corresponding to the triangular push plate is opened on the periphery of the guide rod. A second elastic element is fixedly arranged inside the limiting opening, and a limiting block is fixedly arranged at one end of the second elastic element. The surface of the limiting block is adapted to the corresponding triangular push plate, and a limiting disc is fixedly arranged on the periphery of the guide rod.

[0011] Furthermore, the scraper is connected to two arc-shaped blades by a moving ring. The two arc-shaped blades are arranged in a circular array around the moving ring and together form an S-shaped structure. The arc-shaped blades are in an inclined state, and the bottom of the arc-shaped blades is pointed and fits the surface of the second filter plate.

[0012] Furthermore, a sliding groove is provided on the surface of the guide rod. The sliding groove is formed by splicing a first vertical groove and a first spiral groove. A semi-circular sliding ball is fixedly provided on the inner wall of the second filter plate, and the semi-circular sliding ball slides in conjunction with the sliding groove.

[0013] Furthermore, a sealing filter ring adapted to the inner wall of the filter cylinder is fixedly installed at the bottom of the second filter plate. Several second sleeves are fixedly installed at the bottom of the second filter plate. A third elastic element is fixedly installed inside the second sleeve. A second sleeve rod is fixedly installed at the bottom of the third elastic element. A slidable filter screen that slides with the guide rod is fixedly installed at the bottom of the second sleeve rod. A slidable rod corresponding to the second filter hole is fixedly installed on the surface of the slidable filter screen. A protruding ball is fixedly installed on the inner wall of the slidable filter screen. A second spiral groove with the same spiral direction and angle as the first spiral groove is opened on the circumferential side of the guide rod. A triangular protrusion is spirally arrayed inside the second spiral groove. A triangular sliding groove corresponding to the triangular protrusion is opened on the circumferential side of the guide rod. The second spiral groove and the triangular sliding groove are connected.

[0014] Furthermore, the pretreatment unit has an inlet connected to its interior on one side, and the deep treatment unit has an outlet connected to its interior on one side. Each of the connecting pipes is equipped with a water pump for pumping sewage, and the top of the filter cylinder is detachably equipped with a cover plate, which is spirally connected to the corresponding connecting pipe.

[0015] Furthermore, the filter cylinder has an insertion interface on its circumferential side, and the first filter plate has an arc-shaped plate corresponding to the insertion interface fixedly installed on its circumferential side. The insertion interface is semi-circular, and a support frame is installed on the circumferential side of the filter cylinder, with the support frame placed on the ground.

[0016] Furthermore, the water guide cylinder is set in an inclined state, and a discharge pipe connected to the interior of the water guide cylinder is fixedly installed at the bottom of the water guide cylinder.

[0017] Another objective of this invention is to provide a multi-stage wastewater treatment process based on the environmentally friendly processing of plastic products. The purpose is to solve the problems of sudden local water pressure rise, filter plate deformation and system shutdown caused by flocculent blockage of filter plates in traditional wastewater treatment through a dynamic filtration mechanism, thereby achieving continuous, efficient and low-maintenance wastewater purification.

[0018] To achieve the above objectives, the present invention provides the following technical solution: a multi-stage wastewater treatment process based on environmentally friendly processing of plastic products, comprising the following steps: S1. Wastewater enters the pretreatment unit through the inlet to remove coarse impurities and suspended particles. Then, the wastewater is pumped into the flocculation unit, where flocculants are added to cause colloidal, dissolved pollutants and microplastic particles to coagulate into flocs. S2. Wastewater containing flocculents enters the filter cylinder and undergoes initial coarse filtration through the first filter plate with large pores. Then, it undergoes fine filtration through the second filter plate with small pores. When the second filter pores become clogged, causing the water pressure to rise, the second filter plate moves downward under pressure. The semi-circular sliding ball on its inner wall slides down the first vertical groove of the guide rod to the first spiral groove, triggering the second filter plate 702 to rotate. The connecting ring moves downward, causing the first sleeve rod to stretch the first elastic element, which is fixed to the connecting ring and closely adheres to the surface of the second filter plate to scrape off the clogged flocculents and impurities. The scraped-off impurities fall into the inclined water guide cylinder and are discharged through the discharge pipe. S3. After the impurities are removed, the water pressure decreases, the first elastic element contracts, and the connecting ring is pulled to move the second filter plate up and reset along the first spiral groove. S4. The filtered wastewater enters the biodegradation unit where organic matter is degraded by microorganisms. Subsequently, the advanced treatment unit performs nitrogen and phosphorus removal, advanced oxidation, disinfection, and pH adjustment, and finally discharges the wastewater through the effluent outlet in compliance with standards.

[0019] Compared with the prior art, the present invention has the following beneficial effects: 1. When the water pressure rises due to flocculation of the second filter plate, the system triggers the second filter plate to automatically move downwards via pressure. The semi-circular sliding ball on the inner wall of the second filter plate slides down the first vertical groove of the guide rod to the first spiral groove, driving the second filter plate to rotate and move vertically. The scraper moves with the second filter plate and scrapes off surface impurities. This process unclogs the second filter holes, preventing flocculation and impurities from clogging the second filter holes and preventing the filter plate from deforming and breaking due to continuous accumulation of water pressure. When the filter plate moves to the position of the water guide cylinder, the sewage is diverted through multiple inclined water guide cylinders, significantly reducing the direct impact pressure on the filter plate. Multiple mechanisms ensure the structural integrity of the filter plate, extend the equipment life, ensure continuous and efficient sewage treatment, and more thoroughly remove pollutants, making the effluent meet standards, reducing damage to the aquatic ecosystem, and improving the environmental protection effect of the plastics processing industry.

[0020] 2. During the downward rotation of the second filter plate, the cleaning screen reciprocates to clear the second filter holes, causing impurities inside the second filter holes to be squeezed to the surface of the second filter plate by the cleaning rod. Meanwhile, the S-shaped scraper fixed to the connecting ring moves closely against the surface of the second filter plate, and its inclined pointed blade precisely cuts into the blockage layer, prying the flocculent away from the second filter plate, preventing the impurities from compacting and aggravating the blockage. The scraped impurities then fall into the water guide tube and are discharged, achieving simultaneous impurity removal and collection. At the same time, the sewage is diverted and depressurized through the water guide tube, causing the pressure on the second filter plate to drop sharply, creating conditions for subsequent elastic reset and ensuring that a high filtration efficiency can still be maintained during the unblocking process.

[0021] 3. After the impurities are removed, the water pressure drops, the first elastic element automatically contracts, and the traction connecting ring drives the second filter plate to move up and reset along the first spiral groove. During the reset process, the second filter plate rotates again, and the scraper cleans the surface residue a second time, ensuring that the filter holes are thoroughly unblocked. No backwashing is required throughout the process, which solves the problem of shutdown due to blockage in traditional filter tanks and ensures the continuity and stability of the multi-stage treatment process. Attached Figure Description

[0022] Figure 1 This is a three-dimensional structural diagram of the entire invention; Figure 2 This is a schematic diagram of the overall structure of the filter unit of the present invention; Figure 3 This is a schematic diagram of a half-section structure of the filter unit of the present invention; Figure 4 This is a schematic diagram of the overall structure of the filter plate adjustment assembly of the present invention; Figure 5 This is a schematic diagram of a half-section of the filter plate adjustment assembly of the present invention; Figure 6 for Figure 5 Enlarged structural diagram at point A; Figure 7 A schematic diagram of the overall structure of the filter plate adjustment assembly of the present invention; Figure 8 A partial structural schematic diagram of the filter plate adjustment assembly in this invention; Figure 9 for Figure 8 Enlarged structural diagram at point B; Figure 10 For the present invention Figure 8 Partial structural sectional view; Figure 11 for Figure 10 Enlarged structural diagram at point C; Figure 12 In this invention Figure 10 Partial structural diagram; Figure 13 This is a cross-sectional view showing the fit between the second filter plate and the unblocking filter plate of the present invention; Figure 14 for Figure 13 Enlarged structural diagram at point D; Figure 15 This is a schematic diagram of the scraper of the present invention.

[0023] In the picture: 1. Pretreatment unit; 2. Flocculation unit; 3. Filtration unit; 4. Biodegradation unit; 5. Deep treatment unit; 6. Filter cartridge; 7. Filter plate adjustment assembly; 701. First filter plate; 702. Second filter plate; 703. Guide rod; 704. Connecting rod; 705. Scraper; 706. First filter hole; 707. Second filter hole; 708. First sleeve rod; 709. First elastic element; 710. Connecting ring; 711. First sleeve; 712. Triangular push plate; 71 3. Limiting block; 714. Limiting disc; 715. Moving ring; 716. Arc-shaped knife; 717. First vertical groove; 718. First spiral groove; 719. Sealing filter ring; 720. Second sleeve; 721. Unclogging filter screen; 722. Second spiral groove; 723. Triangular convex plate; 724. Second sleeve rod; 725. Triangular sliding groove; 8. Water guide tube; 9. Water inlet; 10. Water outlet; 11. Cover plate; 12. Arc-shaped plate; 13. Support frame; 14. Discharge pipe. Detailed Implementation

[0024] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0025] Example 1, referring to Figures 1-15 The first embodiment of the present invention provides a multi-stage wastewater treatment system based on environmentally friendly processing of plastic products, including a pretreatment unit 1, a flocculation unit 2, a filtration unit 3, a biodegradation unit 4 and a deep treatment unit 5 connected in sequence by connecting pipes. The filtration unit 3 includes a filter cylinder 6 fixedly connected between the flocculation unit 2 and the biodegradation unit 4, a filter plate adjustment assembly 7 installed inside the filter cylinder 6, and several water guide cylinders 8 fixedly connected to the periphery of the filter cylinder 6 and connected to its interior.

[0026] Specifically, in treating wastewater generated during the environmentally friendly processing of plastic products, the wastewater is introduced into pretreatment unit 1, where large particulate impurities and suspended solids are initially intercepted by a circular screen. The wastewater is then pumped into flocculation unit 2, where flocculants are added. Colloidal particles and small suspended solids in the wastewater (especially fine plastic particles, additives, oil stains, etc. generated from plastic processing) agglomerate to form larger flocs. Subsequently, the wastewater containing these flocs is pumped through a connecting pipe into the filter cartridge 6 of filtration unit 3 for filtration. The filtered wastewater is then pumped into biodegradation unit 4, where aerobic microorganisms decompose organic matter in an aerobic environment, converting it into carbon dioxide and water, thereby degrading the organic matter. The degraded wastewater is then pumped into deep treatment unit 5, where it undergoes denitrification, phosphorus removal, advanced oxidation technology, disinfection, and pH adjustment treatment in sequence, ensuring that the wastewater meets discharge standards before being discharged.

[0027] Reference Figures 4-15The filter plate adjusting assembly 7 includes a first filter plate 701 and a second filter plate 702 sequentially disposed inside the filter cylinder 6. The first filter plate 701 is detachably installed inside the filter cylinder 6, and the second filter plate 702 is located at the bottom of the first filter plate 701 and slides between it and the filter cylinder 6. The filter plate adjusting assembly 7 also includes a guide rod 703 detachably connected to the first filter plate 701. The guide rod 703 is fixedly connected to the filter cylinder 6 via a connecting rod 704, and slides between the guide rod 703 and the second filter plate 702. The circumferential side of the guide rod 703 is slidably provided with a surface that interacts with the second filter plate. A scraper 705 is attached to the second filter plate 702. The scraper 705 is used to scrape off impurities and flocs on the surface of the second filter plate 702 when it moves along the guide rod 703. The pretreatment unit 1 is used to remove coarse impurities and suspended particles from the wastewater. The flocculation unit 2 is used to remove colloidal and dissolved pollutants. The biodegradation unit 4 is used to degrade organic pollutants. The deep treatment unit 5 is used to remove residual pollutants. The surface of the first filter plate 701 is provided with a first filter hole 706. The surface of the second filter plate 702 is provided with a second filter hole 707. The inner diameter of the first filter hole 706 is larger than the inner diameter of the second filter hole 707.

[0028] Specifically, in the initial state, the second filter plate 702 is positioned above the water guide cylinder 8. When the flocculated wastewater enters the filter cylinder 6, it undergoes primary filtration through the first filter plate 701 and then secondary filtration through the second filter plate 702. When the wastewater impacts the second filter plate 702, the surface of the second filter holes 707 becomes clogged, causing the wastewater discharge to gradually decrease. At this time, the pressure of the wastewater on the surface of the second filter plate 702 gradually increases. When the surface pressure of the second filter plate 702 reaches a threshold, the second filter plate 702 moves downward along the guide rod 703. Simultaneously, the second filter plate 702 rotates. The movement and rotation of the second filter plate 702 are automatically triggered by increased water pressure caused by blockage. During this process, the scraper 705 remains in contact with the surface of the second filter plate 702. As the second filter plate 702 rotates, the scraper 705 removes flocculent material and impurities from its surface. When the second filter plate 702 moves downwards through the water guide cylinder 8, the wastewater flow is diverted through each water guide cylinder 8, thereby reducing the water pressure impact on the surface of the second filter plate 702. This process increases the filtration area simultaneously... By changing the water flow path and alleviating local high pressure, the second filter plate 702 is dynamically adjusted and the sewage pressure is released. At the same time, flocculents and impurities are scraped off by the scraper 705 and fall into the water guide tube 8. At this time, the flocculents and impurities on the surface of the second filter plate 702 gradually decrease, the second filter hole 707 is cleared, and the pressure on its surface gradually decreases and becomes less than the pulling force of the reset component. Under the action of the reset component, the second filter plate 702 moves in the opposite direction along the guide rod 703 until the second filter plate 702 returns to the initial position. During this process, sewage is continuously transported. When the pressure on the surface of the second filter plate 702 reaches the threshold again, the second filter plate 702 moves along the above path again, while cleaning the flocculents and impurities on its surface. The whole process is carried out in the continuous flow of sewage, without stopping the filtration operation or manually cleaning the filter plate, which improves the operating efficiency. Through periodic self-cleaning, it is ensured that the filter tube 6 can maintain a relatively stable filtration efficiency and flow rate for a long time under continuous sewage input, avoiding the treatment interruption and efficiency drop caused by complete blockage of the second filter plate 702.

[0029] Reference Figures 4-15 The bottom of the first filter plate 701 is detachably equipped with several first sleeve rods 708. The bottom of the first sleeve rod 708 is fixedly provided with a first elastic element 709. The bottom end of the first elastic element 709 is fixedly provided with a connecting ring 710. The bottom of the connecting ring 710 is fixedly provided with a T-shaped plate. The top of the second filter plate 702 is provided with a T-shaped groove that slides with the T-shaped plate. The top of the connecting ring 710 is fixedly provided with a first sleeve 711 corresponding to the first sleeve rod 708. The first sleeve 711 is sleeved and connected to the corresponding first sleeve rod 708.

[0030] Specifically, during the downward movement of the second filter plate 702 due to the impact of sewage, the connecting ring 710 moves downward, causing the scraper 705 to move downward. The first elastic element 709 is stretched, and the first sleeve 711 moves downward along the first sleeve rod 708 until the second filter hole 707 is cleared and the pressure on its surface gradually decreases and becomes less than the tension of the first elastic element 709. Under the action of the first elastic element 709, the connecting ring 710 moves in the opposite direction, causing the second filter plate 702 to move in the opposite direction until the second filter plate 702 returns to its initial position. The sliding fit between the T-shaped plate and the T-shaped groove, as well as the sliding of the connecting ring 710 along the first sleeve rod 708 through the first sleeve 711, ensure that when the second filter plate 702 moves downward and resets, the restoring force provided by the first elastic element 709 acts on the entire system through the connecting ring 710. This helps to maintain a relatively stable contact pressure between the scraper 705 and the filter plate surface, thus optimizing the scraping effect.

[0031] Reference Figures 4-14 The bottom of the second filter plate 702 is symmetrically fixed with a triangular push plate 712. The guide rod 703 has a limiting opening on its periphery that corresponds to the triangular push plate 712. A second elastic element is fixedly installed inside the limiting opening. A limiting block 713 is fixedly installed at one end of the second elastic element. The surface of the limiting block 713 is adapted to the corresponding triangular push plate 712. A limiting plate 714 is fixedly installed on the periphery of the guide rod 703.

[0032] Specifically, in the initial state, the top of the scraper 705 is in contact with the bottom of the limiting plate 714, the triangular push plate 712 is above the limiting block 713, and the limiting block 713 is inside the corresponding limiting port with its surface in contact with the bottom of the triangular push plate 712, thus forming a firm mechanical stop. This ensures that the second filter plate 702 is absolutely locked in its initial position when it has not reached the clogging threshold, and will not move down unexpectedly due to normal water flow fluctuations or slight clogging. When the sewage impact force is greater than the resultant force of the elastic force of the second elastic element and the surface friction of the limiting block 713, the lock is released, and the second filter plate 702 is pushed downward by the sewage. The triangular push plate 712 moves downward and presses the corresponding limiting block 713. The second elastic element is compressed until the limiting block 713 is completely pressed into the limiting port. At this time, the second filter plate 702 drives the connecting ring 710 and the scraper 705 to move down synchronously. When the scraper 705 When the filter plate moves to the bottom of the limiting port, under the action of the second elastic element, the limiting block 713 moves out along the limiting port and returns to the initial position. This process makes the pressure threshold for triggering downward movement more precise and controllable. After the unblocking and pressure relief are completed, the second filter plate 702 moves upward, driving the scraper 705 to move upward. During this process, the top of the scraper 705 presses against the bottom of the limiting block 713, forcing the second elastic element to compress. The limiting block 713 is then pressed into the limiting port again. When the triangular push plate 712 moves above the limiting block 713, under the action of the second elastic element, the limiting block 713 moves again to the outside of the limiting port and returns to the initial position. The action of the scraper 705 pressing down on the limiting block 713 when it moves upward cleverly avoids interference between the scraper 705 and the limiting block 713 during the reset process, thus preventing it from being unable to reset. All components work together to form a complete, reliable, and interference-resistant self-cleaning cycle.

[0033] Reference Figures 4-15 The scraper 705 is connected to a movable ring 715 and two arc-shaped blades 716. The two arc-shaped blades 716 are fixedly connected in a ring array to the periphery of the movable ring 715, and together they form an S-shaped structure. The arc-shaped blades 716 are in an inclined state, and the bottom of the arc-shaped blades 716 is pointed and fits the surface of the second filter plate 702.

[0034] Specifically, such as Figure 4As shown, when the second filter plate 702 moves downwards, it rotates counterclockwise. The scraper 705 is tilted to the right, making it easier to cut into the bottom of the filter cake layer and pry it up instead of forcibly pushing the entire accumulation layer horizontally. The tilted blade can more effectively decompose and break up the filter cake blocks. Compared with the vertical scraper 705, the tilt angle significantly reduces the frontal resistance when the scraper 705 moves, reduces driving energy consumption, and avoids horizontally pushing and compacting the filter cake into harder and more difficult-to-remove blocks. The bottom of the scraper 705 is designed with a sharp blade that can accurately cut into and adhere to the surface of the second filter plate 702, like a shovel, to completely scrape away the flocculent material adhering to the edge of the filter holes and the surface of the second filter plate 702, maximizing the restoration of the permeability of the second filter plate 702. Compared with a blunt scraper, the sharp blade can more effectively remove embedded material. The scraping effect is maximized by ensuring that the scraper blade 705 adheres to the surface of the second filter plate 702 without gaps, thus minimizing the contact area between the scraper blade 705 and the second filter plate 702. This allows the second filter holes 707 to have more contact with the sewage, thereby increasing the flow rate. The two arc-shaped blades 716 combined into a continuous S-shaped structure increase the complexity and coverage density of the scraper blade 705 path. This allows for more effective agitation and removal of flocculent material at different positions and in different directions on the second filter plate 702 during a single rotation stroke, significantly reducing blind spots and preventing filter cake from accumulating in localized dead zones. The S-shaped flowability and the guiding effect of the inclined blades help to push and concentrate the filter cake along the path of the guide tube 8 while scraping it, facilitating subsequent collection and discharge from the system.

[0035] Reference Figure 4 , Figures 9-14 The guide rod 703 has a sliding groove on its surface. The sliding groove is formed by splicing the first vertical groove 717 and the first spiral groove 718. A semi-circular sliding ball is fixedly provided on the inner wall of the second filter plate 702. The semi-circular sliding ball slides in conjunction with the sliding groove.

[0036] Specifically, as the second filter plate 702 moves downward along the guide rod 703, the semi-circular sliding ball slides along the first vertical groove 717 and the first spiral groove 718 in sequence. When the semi-circular sliding ball moves inside the first spiral groove 718, it drives the second filter plate 702 to rotate spirally. That is, the second filter plate 702 rotates during its movement. The semi-circular sliding ball is strictly restricted to move within the sliding groove. The sliding groove formed by the splicing of the first vertical groove 717 and the first spiral groove 718 determines that the movement trajectory of the second filter plate 702 must first move downward in a straight line and then spiral down, that is, move downward while rotating. This forces the second filter plate 702 to complete the required rotational action during its movement. The rotation causes the surface of the second filter plate 702 to produce a circumferential relative movement with respect to the fixed scraper 705. This movement method can more thoroughly and efficiently scrape away flocculents and impurities adhering to the area around the second filter hole 707 and the surface of the second filter plate 702 than simple vertical movement. When the second filter plate 702 is reset upward under the action of the first elastic element 709, the hemisphere will move in the opposite direction along the first spiral groove 718 and the first vertical groove 717, that is, it first rotates and moves upward, and then moves upward in a straight line. The reverse rotation action avoids the secondary accumulation of impurities. During the reset process, the relative path between the scraper 705 and the filter plate is slightly changed, which helps to prevent the impurities that have just been scraped off from being picked up again or stuck in a specific position during the reset. At the same time, it ensures that when the second filter plate 702 finally returns to the initial position, its orientation is also restored to its original position, ensuring that the initial matching relationship with the limiting block 713, scraper 705 and other components is accurate.

[0037] Reference Figures 8-14The bottom of the second filter plate 702 is fixedly provided with a sealing filter ring 719 that is adapted to the inner wall of the filter cylinder 6. Several second sleeves 720 are fixedly provided at the bottom of the second filter plate 702. A third elastic element is fixedly provided inside the second sleeve 720. The first elastic element 709, the second elastic element and the third elastic element are all springs. A second sleeve rod 724 is fixedly provided at the bottom of the third elastic element. A slidable filter screen 721 that slides with the guide rod 703 is fixedly provided at the bottom of the second sleeve rod 724. The third elastic element provides a buffer for the movement of the slidable filter screen 721. When the slidable filter screen 721 moves, the third elastic element is compressed. A slidable rod corresponding to the corresponding second filter hole 707 is fixedly provided on the surface of the slidable filter screen 721. A protruding ball is fixedly provided on the inner wall of the slidable filter screen 721. The guide rod 703 is located on the periphery of the guide rod 703. A second spiral groove 722 is provided, which has the same spiral direction and angle as the first spiral groove 718. The upper end of the second spiral groove 722 is fixedly connected to a second vertical groove of the same size as the first vertical groove 717 and arranged alternately. The spiral array inside the second spiral groove 722 is provided with a triangular protrusion 723. The guide rod 703 has a triangular sliding groove 725 on its peripheral side, which corresponds to the triangular protrusion 723. The second spiral groove 722 and the triangular sliding groove 725 are connected. The connection structure between the second spiral groove 722 and the triangular sliding groove 725, together with the contact sliding design between the protruding ball and the triangular protrusion 723, makes the up-and-down movement and rotation of the filter screen 721 smoother, avoids jamming or delay, and ensures that the cleaning action can respond quickly when the second filter plate 702 is blocked and the water pressure changes.

[0038] Specifically, when the second filter plate 702 moves downward due to increased water pressure caused by flocculation, the sealing filter ring 719 at its bottom moves downward accordingly, maintaining a sealed fit with the inner wall of the filter cylinder 6. This prevents wastewater from directly passing over the second filter plate 702 and entering the next process when it moves to the connection end of the water guide cylinder 8, ensuring that the filtration process is uninterrupted and does not fail, maintaining a stable filtration effect. At the same time, the third elastic element in the multiple second sleeves 720 fixedly installed at the bottom of the second filter plate 702 pushes the second sleeve rod 724 and the unblocking filter screen 721 connected thereto to move downward. During this process, the semi-circular sliding ball on the inner wall of the second filter plate 702 moves downward along the first vertical groove 717, and the protruding ball on the inner wall of the unblocking filter screen 721 moves downward along the second vertical groove. When the semi-circular sliding ball on the inner wall of the second filter plate 702 engages with the first spiral groove 718 on the surface of the guide rod 703, the protruding ball on the inner wall of the unblocking filter screen 721 adapts to the second spiral groove 722. During the rotation of the second filter plate 702, the raised ball moves along the second spiral groove 722. When the raised ball contacts and slides with the triangular convex plate 723, it moves upward along the triangular sliding groove 725, driving the unclogging filter screen 721 upward synchronously. The unclogging rod on its surface passes through the corresponding second filter hole 707, squeezing the impurities clogging the filter hole onto the surface of the second filter plate 702. When the raised ball moves downward across the triangular sliding groove 725, the unclogging filter screen 721 moves downward synchronously back to the second spiral groove 722. As the second filter plate 702 continues to rotate, it drives the unclogging filter screen 721 to move continuously, so that the unclogging filter screen 721 moves upward back and forth to effectively unclog the filter hole, effectively prevent the clogging from aggravating, and improve the automated cleaning level of the system. Throughout the process, the connection structure between the second spiral groove 722 and the triangular sliding groove 725 ensures that the unclogging filter screen 721 moves smoothly and responds promptly, further enhancing the system's self-cleaning ability and filtration continuity.

[0039] Example 2, refer to Figures 1-12 This is the second embodiment of the present invention, which differs from the first embodiment in that: a water inlet 9 connected to the interior of the pretreatment unit 1 is installed on one side, through which sewage is introduced; a water outlet 10 connected to the interior of the deep treatment unit 5 is installed on one side, through which the treated sewage is discharged; a water pump for pumping sewage is installed on each connecting pipe; a cover plate 11 is detachably installed on the top of the filter cylinder 6, and the cover plate 11 is spirally connected to the corresponding connecting pipe; an insertion interface is opened on the periphery of the filter cylinder 6; an arc-shaped plate 12 corresponding to the insertion interface is fixedly installed on the periphery of the first filter plate 701; the insertion interface is semi-circular; a support frame 13 is installed on the periphery of the filter cylinder 6 and is placed on the ground; the water guide cylinder 8 is set in an inclined state; a discharge pipe 14 connected to the interior of the water guide cylinder 8 is fixedly installed at the bottom of the water guide cylinder 8, and impurities and flocculants entering the water guide cylinder 8 are discharged from the discharge pipe 14.

[0040] Specifically, the first filter plate 701 is inserted into the filter cylinder 6 along the insertion interface. The arc-shaped plate 12 is connected to the filter cylinder 6 by bolts. At the same time, a rubber gasket is provided on the inner side of the arc-shaped plate 12 to seal the insertion interface. The first filter plate 701 is periodically removed by releasing the bolts to clean it periodically. The first filter plate 701 is horizontally inserted into the filter cylinder 6 through the semi-circular insertion interface. The arc-shaped plate 12 fits against the cylinder wall and is fixed with bolts, realizing the quick installation and removal of the first filter plate 701. The rubber gasket on the inner side of the arc-shaped plate 12 ensures a reliable seal of the insertion interface to prevent sewage leakage. During the downward movement of the second filter plate 702, the flocculent on the surface is scraped off by the scraper 705. The flocculent falls into the water guide cylinder 8 and is discharged through the discharge pipe 14. The sewage discharge is controlled by the solenoid valve, which improves the environmental protection effect.

[0041] Based on embodiments 1-2, the working principle of this invention is as follows: Wastewater enters the pretreatment unit 1 through the inlet 9 to remove coarse impurities and suspended particles. The wastewater is then pumped into the flocculation unit 2, where flocculants are added to cause colloidal, dissolved pollutants, and microplastic particles to coagulate into flocs. Wastewater containing flocs enters the filter cylinder 6 and passes sequentially through the first filter plate 701 (large-aperture primary filtration) and the second filter plate 702 (small-aperture fine filtration). When the second filter hole 707 becomes clogged, causing an increase in water pressure, the second filter plate 702 moves downward under pressure. The semi-circular sliding ball on its inner wall slides down along the first vertical groove 717 of the guide rod 703 to the first spiral groove 718, triggering the rotation of the second filter plate 702. During rotation, the scraper 705 (S-shaped inclined sharp blade structure) on the guide rod 703 closely adheres to the first... On the surface of the second filter plate 702, the flocculated material and impurities that cause blockage are scraped off, thereby reducing the pressure on the second filter plate 702. At the same time, the second filter plate 702 moves to the bottom of the water guide tube 8, increasing the water flow cross section and thus diverting the sewage, further reducing the water pressure. The scraped-off impurities fall into the inclined water guide tube 8 and are discharged through the discharge pipe 14. When the second filter plate 702 moves down, the first elastic element 709 is stretched by the first sleeve rod 708. After the impurities are removed, the water pressure decreases, the first elastic element 709 contracts, and pulls the second filter plate 702 up along the first spiral groove 718 to reset. The filtered sewage enters the biodegradation unit 4 (microbial degradation of organic matter) and the deep treatment unit 5 (denitrification and phosphorus removal, advanced oxidation, disinfection and pH adjustment) in sequence, and is finally discharged from the outlet 10 in compliance with standards.

[0042] Example 3, referring to Figures 1-15 This is the third embodiment of the present invention, providing a multi-stage wastewater treatment process based on environmentally friendly processing of plastic products, including the following steps: S1. Wastewater enters the pretreatment unit 1 through the inlet 9 to remove coarse impurities and suspended particles. Then the wastewater is pumped into the flocculation unit 2, where flocculants are added to cause colloidal, dissolved pollutants and microplastic particles to coagulate into flocs. S2. Wastewater containing flocculents enters the filter cylinder 6 and undergoes initial coarse filtration through the first filter plate 701 with large pores. Subsequently, it undergoes fine filtration through the second filter plate 702 with small pores. When the second filter hole 707 becomes clogged, causing the water pressure to rise, the second filter plate 702 moves downward under pressure. The semi-circular sliding ball on its inner wall slides down along the first vertical groove 717 of the guide rod 703 to the first spiral groove 718, triggering the second filter plate 702 to rotate. The connecting ring 710 moves downward, causing the first sleeve rod 708 to stretch the first elastic element 709. The scraper 705 fixed on the connecting ring 710 scrapes off the clogged flocculents and impurities from the surface of the second filter plate 702. The scraped-off impurities fall into the inclined water guide cylinder 8 and are discharged through the discharge pipe 14. S3. After the impurities are removed, the water pressure decreases, the first elastic element 709 contracts, and the connecting ring 710 is pulled to drive the second filter plate 702 to move upward and reset along the first spiral groove 718. S4. The filtered wastewater enters the biodegradation unit 4 where organic matter is degraded by microorganisms. Then, the advanced treatment unit 5 performs denitrification, phosphorus removal, advanced oxidation, disinfection, and pH adjustment. Finally, the wastewater is discharged from the outlet 10 in compliance with standards.

[0043] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A multi-stage wastewater treatment system based on environmentally friendly processing of plastic products, comprising a pretreatment unit (1), a flocculation unit (2), a filtration unit (3), a biodegradation unit (4), and a deep treatment unit (5) connected sequentially by connecting pipes, characterized in that, The filtration unit (3) includes a filter cylinder (6) disposed between the flocculation unit (2) and the biodegradation unit (4), a filter plate adjustment assembly (7) disposed inside the filter cylinder (6), and several water guide cylinders (8) disposed on the periphery of the filter cylinder (6) and connected to its interior. The filter plate adjustment assembly (7) includes a first filter plate (701) and a second filter plate (702) sequentially disposed inside the filter cylinder (6). The first filter plate (701) is detachably installed inside the filter cylinder (6). The second filter plate (702) is located at the bottom of the first filter plate (701) and slides between it and the filter cylinder (6). The filter plate adjustment assembly (7) also includes a guide rod (703) detachably connected to the first filter plate (701). The guide rod (703) is fixedly connected to the filter cylinder (6) through a connecting rod (704). The guide rod (703) slides between it and the second filter plate (702). A scraper (705) is slidably disposed on the periphery of the guide rod (703) and fits against the second filter plate (702). The scraper (705) is fixedly connected to a connecting ring (710). The scraper (705) is used to scrape off impurities and flocculents on the surface of the second filter plate (702) when it moves along the guide rod (703). The pretreatment unit (1) is used to remove coarse impurities and suspended particles from wastewater, the flocculation unit (2) is used to remove colloidal and dissolved pollutants, the biodegradation unit (4) is used to degrade organic pollutants, and the deep treatment unit (5) is used to remove residual pollutants. The bottom of the first filter plate (701) is detachably equipped with a plurality of first sleeve rods (708). The bottom of the first sleeve rod (708) is fixedly provided with a first elastic element (709). The bottom end of the first elastic element (709) is fixedly provided with a connecting ring (710). The bottom of the connecting ring (710) is fixedly provided with a T-shaped plate. The top of the second filter plate (702) is provided with a T-shaped groove that slides with the T-shaped plate. The top of the connecting ring (710) is fixedly provided with a first sleeve (711) corresponding to the first sleeve rod (708). The first sleeve (711) is sleeved and connected to the corresponding first sleeve rod (708). The bottom of the second filter plate (702) is symmetrically fixed with triangular push plates (712). The guide rod (703) has a limiting opening on its periphery corresponding to the triangular push plate (712). A second elastic element is fixedly installed inside the limiting opening. A limiting block (713) is fixedly installed at one end of the second elastic element. The surface of the limiting block (713) is adapted to the corresponding triangular push plate (712). A limiting plate (714) is fixedly installed on the periphery of the guide rod (703). The scraper (705) is composed of a movable ring (715) and two arc-shaped blades (716). The two arc-shaped blades (716) are symmetrically arranged on the periphery of the movable ring (715) and together they form an S-shaped structure. The arc-shaped blades (716) are in an inclined state, and the bottom of the arc-shaped blades (716) is pointed and fits the surface of the second filter plate (702). The guide rod (703) has a sliding groove on its surface. The sliding groove is formed by splicing a first vertical groove (717) and a first spiral groove (718). A semi-circular sliding ball is fixedly provided on the inner wall of the second filter plate (702). The semi-circular sliding ball slides in conjunction with the sliding groove. The second filter plate (702) has a second filter hole (707) on its surface; The bottom of the second filter plate (702) is fixedly provided with a sealing filter ring (719) that is adapted to the inner wall of the filter cylinder (6). The bottom of the second filter plate (702) is fixedly provided with a plurality of second sleeves (720). The second sleeve (720) is fixedly provided with a third elastic element. The bottom of the third elastic element is fixedly provided with a second sleeve rod (724). The bottom of the second sleeve rod (724) is fixedly provided with a slidable filter screen (721) that is slidably engaged with the guide rod (703). The surface of the slidable filter screen (721) is fixedly provided with a filter ring (719) that is compatible with the second filter cylinder (6). The guide rod (707) has a corresponding unblocking rod. The inner wall of the unblocking filter (721) is fixedly provided with a protruding ball. The guide rod (703) has a second spiral groove (722) with the same spiral direction and angle as the first spiral groove (718). The second spiral groove (722) has a triangular protrusion (723) arranged in a spiral array inside. The guide rod (703) has a triangular sliding groove (725) corresponding to the triangular protrusion (723) on its peripheral side. The second spiral groove (722) and the triangular sliding groove (725) are connected.

2. The multi-stage wastewater treatment system based on environmentally friendly processing of plastic products according to claim 1, characterized in that, The first filter plate (701) has a first filter hole (706) on its surface, and the inner diameter of the first filter hole (706) is larger than the inner diameter of the second filter hole (707).

3. The multi-stage wastewater treatment system based on environmentally friendly processing of plastic products according to claim 2, characterized in that, The pretreatment unit (1) has an inlet (9) connected to its interior on one side, and the deep treatment unit (5) has an outlet (10) connected to its interior on one side. Each of the connecting pipes is equipped with a water pump for pumping sewage. The top of the filter cylinder (6) is detachably provided with a cover plate (11). The cover plate (11) is spirally connected to the corresponding connecting pipe. The filter cylinder (6) has an insertion interface on its periphery. The first filter plate (701) has an arc-shaped plate (12) corresponding to the insertion interface fixedly provided on its periphery. The insertion interface is semi-circular. The filter cylinder (6) has a support frame (13) installed on its periphery. The support frame (13) is placed on the ground.

4. The multi-stage wastewater treatment system based on environmentally friendly processing of plastic products according to claim 3, characterized in that, The water guide tube (8) is set in an inclined state, and the bottom of the water guide tube (8) is fixedly provided with a discharge pipe (14) connected to its interior.

5. A multi-stage wastewater treatment process based on environmentally friendly processing of plastic products, employing the multi-stage wastewater treatment system based on environmentally friendly processing of plastic products as described in claim 4, characterized in that, Includes the following steps: S1. Wastewater enters the pretreatment unit (1) through the inlet (9) to remove coarse impurities and suspended particles. Then the wastewater is pumped into the flocculation unit (2) and flocculants are added to cause colloidal, dissolved pollutants and microplastic particles to coagulate into flocs. S2. Wastewater containing flocculents enters the filter cylinder (6) and undergoes coarse filtration through the first filter plate (701) with large pores, followed by fine filtration through the second filter plate (702) with small pores. When the second filter hole (707) is blocked, causing the water pressure to rise, the second filter plate (702) moves downward under pressure. The semi-circular sliding ball on its inner wall slides down along the first vertical groove (717) of the guide rod (703) to the first spiral groove (718), triggering the second filter plate (702) to rotate. The connecting ring (710) moves downward, causing the first sleeve rod (708) to stretch the first elastic element (709). The scraper (705) fixed on the connecting ring (710) scrapes off the blocked flocculents and impurities in close contact with the surface of the second filter plate (702). The scraped impurities fall into the inclined water guide cylinder (8) and are discharged through the discharge pipe (14). S3. After the impurities are removed, the water pressure decreases, the first elastic element (709) contracts, and the connecting ring (710) is pulled to drive the second filter plate (702) to move up and reset along the first spiral groove (718); S4. The filtered wastewater enters the biodegradation unit (4) where organic matter is degraded by microorganisms. Then it is passed into the deep treatment unit (5) for denitrification, phosphorus removal, advanced oxidation, disinfection and pH adjustment. Finally, it is discharged from the outlet (10) in compliance with standards.

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