A sewage recycling device for landscaping water saving and a method thereof

Abstract

The application discloses a kind of garden greening water-saving sewage recycling device and method thereof, it is related to sewage treatment device field.A kind of garden greening water-saving sewage recycling device, including sewage treatment tank, the sewage treatment tank is respectively provided with out slag pipe, liquid inlet pipe, liquid outlet pipe from bottom to top, still include: filter screen one, install in the sewage treatment tank, located liquid inlet pipe top, the filter screen one is used to intercept filtration in the sewage after garden greening to large particle impurities;Filter screen two, install in the sewage treatment tank, located filter screen one top, the filter screen two is used to secondary processing to the sewage after pre-treatment, intercept filtration to small particle impurities therein;The application is by setting filter screen one and the two-stage grading pretreatment structure of filter screen two, large particle impurities and small particle suspended solids are intercepted in turn, effectively avoid subsequent ultrafiltration membrane blockage, prolong the service life of membrane, improve pretreatment effect.

Description

Technical Field

[0001] This invention belongs to the technical field of wastewater treatment devices, specifically, it relates to a wastewater reuse device and method for water conservation in landscaping. Background Technology

[0002] With the continuous expansion of urban landscaping, the demand for irrigation water for landscaping is increasing year by year. At the same time, if a large amount of wastewater generated during the landscaping process (such as irrigation tailwater, landscape water body water exchange, rainwater runoff, maintenance wastewater, etc.) is directly discharged, it will not only cause serious waste of water resources, but also lead to soil and groundwater pollution and damage to the ecological environment.

[0003] Existing wastewater reuse devices for landscaping mostly employ simple sedimentation and single-stage filtration processes. Using only a single-stage filter structure, they cannot effectively separate large particles from small suspended solids, easily leading to clogging of subsequent membrane modules and significantly shortening membrane lifespan. Furthermore, ultrafiltration membrane backwashing often uses a fixed-position spray structure, failing to clean the entire surface of the ultrafiltration membrane thoroughly, making it difficult to completely resolve membrane fouling issues and affecting filtration efficiency. The backwashing process requires external fresh water, increasing water consumption and failing to meet the core design requirements for water conservation in landscaping. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide a wastewater treatment device that can overcome or at least partially solve the above problems.

[0005] To solve the above-mentioned technical problems, the basic concept of the technical solution adopted by the present invention is: a wastewater reuse device for water conservation in landscaping, comprising a wastewater treatment tank, wherein a sludge discharge pipe, a liquid inlet pipe, and a liquid outlet pipe are respectively arranged from bottom to top on the wastewater treatment tank, and further comprising:

[0006] Filter screen one is installed inside the sewage treatment tank, located above the inlet pipe. Filter screen one is used to intercept and filter large particulate impurities in the sewage after landscaping. Filter screen two is installed inside the sewage treatment tank, above filter screen one. Filter screen two is used to perform secondary treatment on the pretreated sewage and to intercept and filter out small particulate impurities. A membrane treatment assembly is installed on top of the wastewater treatment tank, and the membrane treatment assembly is used for further treatment of wastewater; Wastewater from landscaping is fed into the wastewater treatment tank through the inlet pipe. It is then filtered sequentially through filter screen one and filter screen two, and finally treated by the filter membrane treatment module to remove suspended solids, colloids, bacteria, and large molecular organic impurities from the wastewater. Finally, it is discharged through the outlet pipe at the top.

[0007] Furthermore, the filter membrane treatment assembly includes a filter cartridge, an ultrafiltration membrane, and a backwashing assembly. The filter cartridge is installed inside the wastewater treatment tank, the ultrafiltration membrane is laid on the surface of the filter cartridge, and the backwashing assembly is installed inside the wastewater treatment tank for cleaning the ultrafiltration membrane through backwashing.

[0008] Furthermore, the backwashing assembly includes a rotating spray bar, a floating ring, and nozzles. Multiple sets of the rotating spray bars are rotatably connected inside the filter cartridge, with the spraying ends of the rotating spray bars facing the inner wall of the filter cartridge. The floating ring is slidably connected inside the filter cartridge, and multiple sets of nozzles are installed in a ring at equal intervals, with the nozzles facing the inner wall of the filter cartridge.

[0009] Furthermore, a collection bucket with a top opening is fixedly connected inside the filter cartridge, and a piston plate is slidably connected inside the collection bucket. A liquid outlet and a liquid inlet with one-way valves are installed at the bottom of the collection bucket. The liquid outlet end of the liquid outlet is connected to the nozzle, and a liquid outlet with a one-way valve is installed on the piston plate. The liquid outlet end of the liquid outlet is connected to the rotating spray bar.

[0010] Furthermore, a lead screw is fixedly connected to the piston plate, and a bushing is slidably connected to the lead screw, the bushing being fixedly connected to the rotating spray bar.

[0011] Furthermore, a telescopic cylinder is fixedly connected to the top of the sewage treatment tank, and the telescopic end of the telescopic cylinder is located inside the sewage treatment tank. The telescopic end of the telescopic cylinder is fixedly connected to a lead screw.

[0012] Furthermore, a rotary connector is installed on the bushing, and the two ends of the rotary connector are respectively connected to the rotary spray bar and the liquid outlet.

[0013] Furthermore, a water bladder is installed inside the floating ring. The inlet end of the water bladder is connected to the outlet port, and the outlet end of the water bladder is connected to the nozzle. The water bladder can overcome the buoyancy of the floating ring, thereby causing the floating ring to sink into the water. Then, the nozzle backwashes the area below the ultrafiltration membrane.

[0014] A method for using a wastewater reuse device for water conservation in landscaping mainly includes the following steps: Step 1: Wastewater Input and Pretreatment: Wastewater from landscaping is input into the wastewater treatment tank through the inlet pipe. The wastewater flows from bottom to top through the tank, first passing through a filter screen to intercept and filter large particles, removing coarse suspended solids. Then, the wastewater continues to flow upwards and passes through a second filter screen for secondary fine filtration, intercepting small particles, colloidal suspended solids, and residual debris, completing the pretreatment of the wastewater and providing stable influent conditions for subsequent membrane filtration. Step 2, Membrane Filtration Deep Purification: The pretreated wastewater enters the outside of the filter cartridge and undergoes deep filtration through the ultrafiltration membrane laid on the surface of the filter cartridge. The ultrafiltration membrane efficiently intercepts suspended solids, colloids, bacteria and large molecular organic impurities in the wastewater, achieving harmless purification of the wastewater. The purified water enters the inside of the filter cartridge and is finally discharged through the outlet pipe for reuse in landscaping irrigation. Step 3: Backwashing Cleaning Start-up: When the ultrafiltration membrane reaches the set transmembrane pressure difference threshold or a fixed operating cycle, the backwashing assembly is started to clean the ultrafiltration membrane online. First, the telescopic cylinder drives the lead screw to move downward, and the lead screw drives the piston plate to slide downward in the collection tank. Under the squeezing action of the piston plate, the purified water in the collection tank is transported to the rotating spray bar through the outlet and the rotating connector. At the same time, during the downward movement of the lead screw, the screw drive drives the bushing and the rotating spray bar to rotate around the central axis of the filter cartridge. The rotating spray bar sprays the purified water in a high-pressure manner to backwash the ultrafiltration membrane on the inner wall of the filter cartridge, removing reversible contaminants deposited on the surface of the ultrafiltration membrane. Step 4: Floating ring-assisted deep backwashing: While the piston plate is pressing down, part of the purified water in the collection tank is transported to the water bladder in the floating ring through the liquid outlet. The water bladder is an elastic rubber bladder that gradually expands after the water is injected, overcoming the buoyancy of the floating ring and driving the floating ring to slide down along the inner wall of the filter cartridge. Multiple nozzles on the floating ring simultaneously spray the purified water in the opposite direction onto the surface of the ultrafiltration membrane, performing a comprehensive and thorough deep backwash of the middle and lower areas of the ultrafiltration membrane, completely removing residual contaminants from the surface of the ultrafiltration membrane. Step 5, Backwash Reset and Circulation: After backwashing is completed, the telescopic cylinder drives the screw to reset upward, the piston plate slides upward synchronously, the collection tank is replenished with purified water through the liquid inlet, the water in the water bladder is emptied at the same time, the floating ring resets upward along the inner wall of the filter cartridge under the action of buoyancy, the rotating spray bar resets synchronously, the device returns to normal filtration operation, and one filtration backwash cycle is completed. Step Six: Sludge and Impurity Discharge: During the operation of the device, large and small particles of impurities intercepted by Filter Screen 1 and Filter Screen 2 are deposited to the bottom of the sewage treatment tank under the action of gravity. The deposited sludge and impurities are periodically discharged from the device through the sludge discharge pipe to complete the periodic maintenance of the device and ensure the long-term stable operation of the device.

[0015] After adopting the above technical solution, the present invention has the following beneficial effects compared with the prior art: The present invention sets up a two-stage pretreatment structure of filter screen one and filter screen two to intercept large particulate impurities and small particulate suspended matter in sequence, effectively avoiding subsequent ultrafiltration membrane clogging, extending membrane service life, and improving pretreatment effect. Attached Figure Description

[0016] In the attached diagram: Figure 1This is a schematic diagram of the structure of a wastewater reuse device and method for water conservation in landscaping proposed in this invention; Figure 2 This is a schematic cross-sectional view of a wastewater reuse device and method for water conservation in landscaping proposed in this invention. Figure 1 ; Figure 3 This is a schematic cross-sectional view of a wastewater reuse device and method for water conservation in landscaping proposed in this invention. Figure 2 ; Figure 4 This invention proposes a wastewater reuse device and method for water conservation in landscaping. Figure 3 A schematic diagram of the structure of part A; Figure 5 This invention proposes a wastewater reuse device and method for water conservation in landscaping. Figure 4 A structural diagram of section B; Figure 6 This is a schematic diagram of the filter membrane treatment component in a wastewater reuse device and method for water conservation in landscaping proposed in this invention.

[0017] In the diagram: 1. Wastewater treatment tank; 101. Inlet pipe; 102. Outlet pipe; 103. Sludge discharge pipe; 201. Filter screen one; 202. Filter screen two; 3. Filter cylinder; 401. Collection bucket; 402. Piston plate; 403. Inlet; 404. Secondary outlet; 405. Outlet; 5. Rotary connector; 601. Bushing; 602. Rotary spray bar; 701. Telescopic cylinder; 702. Lead screw; 801. Floating ring; 802. Water bladder; 803. Nozzle. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments will be clearly and completely described below with reference to the accompanying drawings. The following embodiments are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0019] Example: Refer to Figure 1-6Wastewater treatment tank 1 is a vertical cylindrical tank structure, welded from 304 stainless steel with a 5mm thick wall, possessing good corrosion resistance and structural strength, suitable for long-term use in outdoor landscaping scenarios. The volume of wastewater treatment tank 1 is 1-5m³, which can be flexibly adjusted according to the scale of the landscaping project. From bottom to top, wastewater treatment tank 1 is equipped with a sludge discharge pipe 103, a liquid inlet pipe 101, and a liquid outlet pipe 102: the sludge discharge pipe 103 is installed at the bottom center of wastewater treatment tank 1, with a diameter of DN50, and is equipped with a manual ball valve for discharging deposited sludge and impurities; the liquid inlet pipe 101 is installed on the lower side wall of wastewater treatment tank 1, 300mm from the bottom, with a diameter of DN80, for inputting wastewater after landscaping; the liquid outlet pipe 102 is installed on the top side wall of wastewater treatment tank 1, 200mm from the top, with a diameter of DN65, for discharging purified reclaimed water.

[0020] Inside the wastewater treatment tank 1, filter screen 1 201 and filter screen 2 202 are fixedly installed by a stainless steel bracket. Filter screen 201 is located above the inlet pipe 101, 150mm from the center of the inlet pipe 101. It is made of 304 stainless steel woven filter screen with an 8mm aperture and a mesh size of 2. It is sealed to the tank by bolts and is used to intercept and filter large particulate impurities in the wastewater after landscaping. Large particulate impurities include garden leaves, withered grass debris, sand, plant fibers and other coarse suspended matter. Filter screen 202 is installed above filter screen 201, 200mm from the top of filter screen 201. It is made of 304 stainless steel woven filter screen with a pore size of 2mm and a mesh count of 10. It is also connected to the tank by bolts for sealing. It is used to perform secondary fine filtration on the wastewater after pretreatment by filter screen 201, intercepting small particulate impurities, colloidal suspended solids and residual debris in the wastewater, completing the two-stage pretreatment of wastewater, providing stable water inlet conditions for subsequent membrane filtration, and effectively preventing large particulate impurities from entering the membrane module and causing blockage.

[0021] A filter membrane treatment assembly is fixedly installed on the top of the wastewater treatment tank 1 by a stainless steel bracket. The filter membrane treatment assembly includes a filter cartridge 3, an ultrafiltration membrane, and a backwashing assembly. The filter cartridge 3 is a cylindrical structure made of food-grade PP material. It has a diameter of 300mm and a height of 800mm. The cylinder wall is evenly provided with water permeable holes with a diameter of 5mm and a spacing of 10mm, which are used to pass through the purified water. The ultrafiltration membrane is an enhanced PVDF hollow fiber ultrafiltration membrane with an inner diameter of 0.8 mm, an outer diameter of 1.2 mm, and a pore size of 0.02 μm. It is laid on the outer surface of the filter cartridge 3 and sealed and fixed with epoxy resin. It can efficiently intercept suspended solids, colloids, bacteria and macromolecular organic impurities in wastewater, and achieve harmless purification of wastewater. The purified water enters the interior of the filter cartridge 3 through the water permeable holes on the surface of the filter cartridge 3, and is finally discharged through the liquid outlet pipe 102. The backwashing assembly is installed inside the filter cartridge 3 and is used to perform online backwashing cleaning of the ultrafiltration membrane to restore the filtration flux of the ultrafiltration membrane.

[0022] The backwash assembly includes a rotating spray bar 602, a float ring 801, and a nozzle 803. There are 4 sets of rotating spray bars 602 arranged in a cross shape. They are rotatably connected to the center of the filter cartridge 3 through stainless steel bearings. The spraying end of the rotating spray bar 602 faces the inner wall of the filter cartridge 3, that is, the inner surface of the ultrafiltration membrane. The diameter of the spray bar is DN15. The spraying end is equipped with a fan-shaped high-pressure nozzle with a spraying angle of 120°, which is used for reverse spraying to purify the water and flush the ultrafiltration membrane. The floating ring 801 is an annular floating structure made of high-density EPS foam material with a density of 20kg / m³, which has good buoyancy. The inner diameter of the floating ring 801 is the same as the outer diameter of the filter cartridge 3, and it slides against the outer wall of the filter cartridge 3. Twelve sets of nozzles 803 are installed in a ring at equal intervals on the floating ring 801. The nozzles 803 are high-pressure fan-shaped nozzles, and the spray end faces the inner wall of the filter cartridge 3, that is, the inner surface of the ultrafiltration membrane, for backwashing the ultrafiltration membrane.

[0023] A collection tank 401 with a top opening is fixedly connected to the center of the filter cartridge 3 via a stainless steel bracket. The collection tank 401 is a cylindrical barrel structure made of 304 stainless steel, with a diameter of 200mm and a height of 300mm. The bottom of the barrel is fixed to the bottom surface of the filter cartridge 3 with bolts. A piston plate 402 is slidably connected inside the collection tank 401. The piston plate 402 is a circular plate structure with a diameter of 198mm. A nitrile rubber sealing ring is installed on the outer ring, which slides and seals against the inner wall of the collection tank 401 to squeeze the purified water inside the collection tank 401. The bottom of the collection tank 401 is equipped with two ports with one-way valves: an inlet 403 and an outlet 404. The one-way valve of the inlet 403 is a duckbill type, allowing only purified water to enter the collection tank 401 from inside the filter cartridge 3. The one-way valve of the outlet 404 is a spring-loaded type, allowing only purified water inside the collection tank 401 to be discharged. The outlet end of the outlet 404 is connected to the nozzle 803 on the float ring 801 via a PE pipe to provide backwash water for the nozzle 803. An outlet 405 with a one-way valve is installed at the top center of the piston plate 402. The one-way valve of the outlet 405 is a spring-loaded type, allowing only purified water inside the collection tank 401 to be discharged. The outlet end of the outlet 405 is connected to the rotating spray bar 602 via a PE pipe to provide backwash water for the rotating spray bar 602.

[0024] A lead screw 702 is fixedly connected to the top center of the piston plate 402. The lead screw 702 is a cylindrical trapezoidal lead screw with a diameter of 20mm and a lead of 5mm. The axis of the lead screw 702 coincides with the axis of the collection tank 401. A bushing 601 is threadedly slidably connected to the lead screw 702. The inner ring of the bushing 601 has an internal thread that matches the lead screw 702. The bushing 601 and the lead screw 702 are threadedly connected. The outer ring of the bushing 601 is fixedly connected to the inner end of the four sets of rotating spray bars 602 by bolts. When the lead screw 702 moves up and down, it drives the bushing 601 to rotate around the axis of the lead screw 702 through threaded transmission, thereby driving the rotating spray bars 602 to rotate synchronously. A telescopic cylinder 701 is fixedly connected to the center of the top of the sewage treatment tank 1. The telescopic cylinder 701 is an electric telescopic cylinder with a stroke of 300mm and a thrust of 500N. The telescopic end of the telescopic cylinder 701 passes through the top of the sewage treatment tank 1 and is located inside the sewage treatment tank 1. The telescopic end of the telescopic cylinder 701 is fixedly connected to the top of the lead screw 702 through a flange, which is used to drive the lead screw 702 to move up and down, thereby driving the piston plate 402 to slide up and down, realizing the squeezing and replenishment of the produced water inside the collection tank 401. A rotary connector 5 is installed on the bushing 601. The rotary connector 5 is a stainless steel rotary pipe joint with a nominal pressure of 1.6MPa. The fixed end of the rotary connector 5 is connected to the PE pipe at the outlet end of the outlet 405, and the rotating end of the rotary connector 5 is connected to the PE pipe at the inner end of the rotary spray bar 602, which is used to maintain the sealing and connection of the pipeline while the rotary spray bar 602 rotates to prevent water leakage.

[0025] The floating ring 801 has an annular mounting groove inside, in which a water bladder 802 is installed. The water bladder 802 is an annular elastic rubber bladder made of food-grade nitrile rubber with a wall thickness of 3mm, possessing good elasticity and aging resistance. The inlet end of the water bladder 802 is connected to the outlet end of the outlet port 404 via a PE pipe, and the outlet end of the water bladder 802 is connected to the 12 sets of nozzles 803 on the floating ring 801 via a PE pipe. When purified water is injected into the water bladder 802, the water bladder 802 gradually expands, increasing its weight from 0.5kg to 3kg, overcoming the buoyancy of the floating ring 801, and driving the floating ring 801 to slowly slide downwards along the inner wall of the filter cartridge 3 at a speed of 5mm / s. When the purified water inside the water bladder 802 is emptied, the floating ring 801 returns to its original position along the inner wall of the filter cartridge 3 under its own buoyancy, realizing the up-and-down reciprocating motion of the floating ring 801, and performing backwashing of the entire surface of the ultrafiltration membrane without dead angles.

[0026] Detailed instructions on the method and operation steps Step 1: Wastewater Input and Pretreatment Wastewater from landscaping (including irrigation tailwater, water exchange in landscape water bodies, rainwater runoff, and maintenance wastewater) is fed into wastewater treatment tank 1 through inlet pipe 101 at a flow rate of 10 m³ / h. Inside tank 1, the wastewater flows from bottom to top. First, it flows through filter screen 201, which performs primary filtration to remove large particles (such as fallen leaves, withered grass debris, sand, and plant fibers), achieving an interception efficiency of over 95% and preventing these large particles from entering subsequent treatment units. Then, the wastewater continues upwards through filter screen 202, which performs secondary fine filtration to remove small particles, colloidal suspended solids, and residual debris, achieving an interception efficiency of over 90%. This completes the two-stage pretreatment of the wastewater, providing stable influent conditions for subsequent ultrafiltration membrane filtration, effectively protecting the ultrafiltration membrane and preventing clogging.

[0027] Step 2: Membrane Filtration for Deep Purification After two stages of pretreatment, the wastewater enters the outer space of filter cartridge 3. Under a working pressure of 0.1 MPa, the wastewater passes through the ultrafiltration membrane laid on the outer surface of filter cartridge 3. The ultrafiltration membrane efficiently intercepts suspended solids, colloids, bacteria, and large molecular organic impurities in the wastewater, achieving a suspended solids removal rate of over 99% and a bacteria removal rate of over 99.9%, thus achieving harmless purification of the wastewater. The purified permeate enters the interior of filter cartridge 3 through the permeable holes on its surface. The turbidity of the permeate is ≤0.1 NTU, which meets the standard of GB / T25499-2010 "Urban Wastewater Reuse for Green Space Irrigation". Most of the permeate (approximately 90%) is discharged through the outlet pipe 102 for reuse in landscaping irrigation. A small portion of the permeate (approximately 10%) enters the collection tank 401 through the inlet 403 at the bottom of the collection tank 401 for storage and subsequent backwashing.

[0028] Step 3: Backwash Cleaning Start When the ultrafiltration membrane reaches the set transmembrane pressure difference threshold (25 kPa) or a fixed operating cycle (45 minutes), the system automatically starts the backwashing component to clean the ultrafiltration membrane online. First, the telescopic cylinder 701 is activated, driving the lead screw 702 downward at a speed of 10 mm / s. The lead screw 702 drives the piston plate 402 to slide downward inside the collection tank 401. Under the squeezing action of the piston plate 402, the pressure of the purified water inside the collection tank 401 increases to 0.2 MPa. It is then transported to the rotary spray bar 602 through the outlet 405 on the piston plate 402 via the rotary connector 5. At the same time, as the lead screw 702 moves downward, it drives the bushing 601 to rotate around the central axis of the filter cartridge 3 at a speed of 10 r / min through the threaded drive. The bushing 601 drives the four sets of rotary spray bars 602 to rotate synchronously. The rotary spray bars 602 spray the high-pressure purified water in a fan-shaped manner to backwash the ultrafiltration membrane on the inner wall of the filter cartridge 3, removing reversible pollutants (such as suspended solids, colloids, sludge flocs, etc.) deposited on the surface of the ultrafiltration membrane, thus completing the backwashing of the upper area of ​​the ultrafiltration membrane.

[0029] Step 4: Float ring-assisted deep backwashing While the piston plate 402 presses down on the water inside the collection tank 401, a portion of the purified water (approximately 30%) is transported through the outlet 404 at the bottom of the collection tank 401 to the water bladder 802 inside the float ring 801. The water bladder 802 is an elastic rubber bladder that gradually expands under the injection of purified water, increasing in weight and overcoming the buoyancy of the float ring 801. This causes the float ring 801 to slide slowly downwards along the inner wall of the filter cartridge 3 at a speed of 5 mm / s. Simultaneously, the 12 sets of nozzles 803 on the float ring 801 spray 0.2 MPa high-pressure purified water in a fan-shaped jet pattern onto the inner surface of the ultrafiltration membrane, performing a comprehensive and thorough backwash of the lower and middle areas of the ultrafiltration membrane. This completely removes residual contaminants from the surface of the ultrafiltration membrane, solving the problem of blind spots in conventional backwashing.

[0030] Step 5: Backwashing, Reset, and Circulation The backwashing time is set to 30 seconds. After backwashing, the telescopic cylinder 701 drives the lead screw 702 to return to its original position at a speed of 10 mm / s. The lead screw 702 drives the piston plate 402 to slide upward inside the collection tank 401, forming a negative pressure of -0.05 MPa inside the collection tank 401. Purified water is replenished from inside the filter cartridge 3 through the liquid inlet 403, preparing for the next backwash. At the same time, the purified water inside the water bladder 802 is gradually emptied under the buoyancy of the floating ring 801. The water bladder 802 contracts, and the floating ring 801 returns to its original position along the inner wall of the filter cartridge 3 under its own buoyancy. The rotating spray bar 602 also returns to its original position synchronously under the drive of the lead screw 702. The device returns to normal filtration operation, completing one filtration-backwash cycle and achieving continuous and stable operation of the device.

[0031] Step Six: Discharge of Sludge and Impurities During long-term operation of the device, large and small particles of impurities intercepted by filter screens 201 and 202 gradually settle to the bottom of wastewater treatment tank 1 under gravity, forming a sludge and impurity sediment layer with a thickness of approximately 100mm. The manual ball valve on the sludge discharge pipe 103 is opened periodically (once a week) to discharge the deposited sludge and impurities from the device. The discharged sludge can be composted and used as organic fertilizer for landscaping, realizing the resource utilization of waste. After discharge, the ball valve is closed, and the device resumes normal operation. No disassembly is required, making maintenance and operation simple and suitable for unattended outdoor operation scenarios in landscaping.

[0032] The ultrafiltration membrane used in this device is an enhanced PVDF hollow fiber ultrafiltration membrane, with an applicable temperature range of 5-40℃ and an optimal operating temperature of 20-30℃. It can be adapted to different regional climate conditions through underground installation or insulation layer design. The backwashing parameters can be flexibly adjusted according to actual operating conditions. The backwashing pressure can be set to 0.15-0.3MPa, the backwashing duration can be set to 20-60 seconds, and the backwashing cycle can be set to 30-60 minutes. The device can be equipped with an Internet of Things (IoT) control system to realize functions such as remote monitoring, automatic backwashing, and automatic slag discharge, further improving the degree of automation.

[0033] Staged pretreatment and membrane assembly protection: By setting up a two-stage staged pretreatment structure with filter screen 1 201 and filter screen 2 202, large particulate impurities and small particulate suspended matter are intercepted in sequence, which effectively avoids subsequent ultrafiltration membrane clogging, extends membrane service life, and improves pretreatment effect. Dual-mode backwashing with no blind spots: Through the dual-mode backwashing structure of the rotating spray bar 602 and the floating ring 801, the rotating spray bar 602 rotates and washes the upper area of ​​the ultrafiltration membrane, while the floating ring 801 slides up and down along the filter cartridge 3 to clean the middle and lower areas, achieving full-surface cleaning of the ultrafiltration membrane without dead corners and completely solving the blind spot problem of existing backwashing. Self-generated water backwashing, water-saving and efficient: The backwashing water uses the purified water produced by the device itself, without the need for external fresh water, which greatly saves water resources and fully meets the design requirements for water-saving in landscaping. Pump-free backwashing reduces energy consumption: Through the structure of the collection tank 401 and the piston plate 402, backwashing is achieved by using piston squeezing to produce water, eliminating the need for an additional backwashing pump and reducing the energy consumption and manufacturing cost of the device. Easy to operate and maintain, suitable for outdoor scenarios: The sludge and impurities are discharged regularly through the slag discharge pipe 103 without disassembling the device. The maintenance and operation are simple and suitable for long-term unattended operation scenarios in landscaping. The process is complete and highly automated: the method covers the entire chain of wastewater input, pretreatment, membrane purification, backwashing, reset, and maintenance, and can achieve automated operation, which meets the requirements of the energy-saving and environmental protection industry.

[0034] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-described technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A wastewater reuse device for landscaping and greening, comprising a wastewater treatment tank (1), wherein the wastewater treatment tank (1) is provided with a slag discharge pipe (103), a liquid inlet pipe (101), and a liquid outlet pipe (102) from bottom to top, characterized in that, Also includes: Filter screen one (201) is installed inside the sewage treatment tank (1) and located above the inlet pipe (101). Filter screen one (201) is used to intercept and filter large particulate impurities in the sewage after landscaping. Filter screen two (202) is installed inside the sewage treatment tank (1) and located above filter screen one (201). Filter screen two (202) is used to perform secondary treatment on the pretreated sewage and to intercept and filter small particulate impurities in it. A filter membrane treatment assembly is installed on top of the wastewater treatment tank (1) and is used to further treat the wastewater. Wastewater from landscaping is fed into the wastewater treatment tank (1) through the inlet pipe (101), filtered sequentially by filter screen one (201) and filter screen two (202), and finally treated by the filter membrane treatment component to remove suspended solids, colloids, bacteria and macromolecular organic impurities from the wastewater, and finally discharged through the outlet pipe (102) at the top.

2. The device according to claim 1, characterized in that, The filter membrane treatment assembly includes a filter cartridge (3), an ultrafiltration membrane, and a backwashing assembly. The filter cartridge (3) is installed inside the wastewater treatment tank (1), the ultrafiltration membrane is laid on the surface of the filter cartridge (3), and the backwashing assembly is installed inside the wastewater treatment tank (1) to clean the ultrafiltration membrane through backwashing.

3. The device according to claim 2, characterized in that, The backwashing assembly includes a rotating spray bar (602), a floating ring (801), and a nozzle (803). Multiple sets of the rotating spray bars (602) are rotatably connected inside the filter cylinder (3), and the spraying end on the rotating spray bar (602) faces the inner wall of the filter cylinder (3). The floating ring (801) is slidably connected inside the filter cylinder (3), and multiple sets of nozzles (803) are installed in a ring at equal intervals on the floating ring (801), with the nozzles (803) facing the inner wall of the filter cylinder (3).

4. The device according to claim 3, characterized in that, The filter cartridge (3) is fixedly connected to a collection bucket (401) with a top opening. A piston plate (402) is slidably connected inside the collection bucket (401). The bottom of the collection bucket (401) is equipped with a liquid outlet (404) with a one-way valve and a liquid inlet (403). The liquid outlet end of the liquid outlet (404) is connected to the nozzle (803). The piston plate (402) is equipped with a liquid outlet (405) with a one-way valve. The liquid outlet end of the liquid outlet (405) is connected to the rotating spray bar (602).

5. The device according to claim 4, characterized in that, A lead screw (702) is fixedly connected to the piston plate (402), and a bushing (601) is threadedly slidably connected to the lead screw (702). The bushing (601) is fixedly connected to the rotating spray bar (602).

6. The device according to claim 5, characterized in that, The top of the sewage treatment tank (1) is fixedly connected to a telescopic cylinder (701). The telescopic end of the telescopic cylinder (701) is located inside the sewage treatment tank (1). The telescopic end of the telescopic cylinder (701) is fixedly connected to a lead screw (702).

7. The device according to claim 5, characterized in that, A rotary connector (5) is installed on the bushing (601), and the two ends of the rotary connector (5) are connected to the rotary spray bar (602) and the liquid outlet (405) respectively.

8. The device according to claim 4, characterized in that, A water bladder (802) is installed inside the floating ring (801). The inlet end of the water bladder (802) is connected to the outlet port (404), and the outlet end of the water bladder (802) is connected to the nozzle (803). The water bladder (802) can overcome the buoyancy of the floating ring (801), thereby causing the floating ring (801) to sink into the water. Then, the nozzle (803) is used to backwash the area below the ultrafiltration membrane.

9. The device according to claim 8, characterized in that, The water bladder (802) is an elastic rubber bladder.

10. A method for the garden greening water-saving sewage recycling device of claim 8, characterized in that, The main operating steps include the following: Step 1, Wastewater Input and Pretreatment: Wastewater from landscaping is input into wastewater treatment tank (1) through inlet pipe (101). The wastewater flows from bottom to top through wastewater treatment tank (1). First, large particulate impurities in the wastewater are filtered through filter screen (201) to remove coarse suspended solids in the wastewater. The wastewater then continues to flow upwards and passes through filter screen two (202) for secondary fine filtration of the wastewater after primary filtration. This intercepts small particulate impurities, colloidal suspended solids and residual debris in the wastewater, completing the pretreatment of the wastewater and providing stable influent conditions for subsequent membrane filtration. Step 2, Membrane Filtration Deep Purification: The pretreated wastewater enters the outside of the filter cartridge (3) and is deeply filtered by the ultrafiltration membrane laid on the surface of the filter cartridge (3). The ultrafiltration membrane efficiently intercepts suspended solids, colloids, bacteria and macromolecular organic impurities in the wastewater, achieving harmless purification of the wastewater. The purified water enters the inside of the filter cartridge (3) and is finally discharged through the outlet pipe (102) for reuse in garden greening irrigation. Step 3, Backwash Cleaning Start-up: When the ultrafiltration membrane reaches the set transmembrane pressure difference threshold or a fixed operating cycle, start the backwash assembly to clean the ultrafiltration membrane online; First, the telescopic cylinder (701) drives the screw (702) to move downward, and the screw (702) drives the piston plate (402) to slide downward in the collection tank (401). The purified water in the collection tank (401) is squeezed by the piston plate (402) and transported to the rotating spray bar (602) through the outlet (405) and the rotating connector (5). At the same time, during the downward movement of the screw (702), the bushing (601) and the rotating spray bar (602) are driven to rotate around the central axis of the filter cylinder (3) through the thread drive. The rotating spray bar (602) sprays the purified water in a high-pressure manner to backwash the ultrafiltration membrane on the inner wall of the filter cylinder (3) and peel off the reversible pollutants deposited on the surface of the ultrafiltration membrane; Step 4, Floating Ring Assisted Deep Backwashing: While the piston plate (402) is pressing down, part of the purified water in the collection tank (401) is transported through the liquid outlet (404) to the water bladder (802) in the floating ring (801). The water bladder (802) is an elastic rubber bladder that gradually expands after the water is injected, overcoming the buoyancy of the floating ring (801) and driving the floating ring (801) to slide down along the inner wall of the filter cartridge (3). Multiple sets of nozzles (803) on the floating ring (801) simultaneously spray the purified water in the opposite direction onto the surface of the ultrafiltration membrane, performing a comprehensive and thorough deep backwashing of the middle and lower part of the ultrafiltration membrane, and completely removing residual pollutants from the surface of the ultrafiltration membrane. Step 5, Backwash Reset and Circulation: After backwashing is completed, the telescopic cylinder (701) drives the screw (702) to reset upward, the piston plate (402) slides upward synchronously, the collection bucket (401) replenishes purified water through the liquid inlet (403), and at the same time the water in the water bag (802) is emptied. The floating ring (801) resets upward along the inner wall of the filter cylinder (3) under the action of buoyancy, the rotating spray bar (602) resets synchronously, the device returns to normal filtration operation, and one filtration backwash cycle is completed; Step 6, Sludge and impurity discharge: During the operation of the device, large and small particles of impurities intercepted by filter screen 1 (201) and filter screen 2 (202) are deposited to the bottom of the sewage treatment tank (1) under the action of gravity. The deposited sludge and impurities are periodically discharged from the device through the sludge discharge pipe (103) to complete the periodic maintenance of the device and ensure the long-term stable operation of the device.

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