Downward subsurface flow constructed wetland sludge discharge system

Abstract

The invention relates to a downstream subsurface flow constructed wetland sludge discharge system which comprises a planting layer, a water distribution pipe, a filler layer and a reverse osmosis layer which are sequentially arranged from top to bottom, and a sludge collection-drainage layer for mud-water separation is arranged below the reverse osmosis layer. The device has the beneficial effects that micro-polluted water is uniformly distributed on the filler layer through the water distribution pipe, the micro-polluted water flows to the reverse osmosis layer after being treated by the filler layer, sewage flowing out of the reverse osmosis layer enters the sludge collection-drainage layer, and the reverse osmosis layer can filter large-particle-size filler so as to prevent the large-particle-size filler from falling to the sludge collection-drainage layer, so that a reverse filtration effect is achieved; therefore, the sludge collection-drainage layer is prevented from being blocked to a certain extent, the sludge collection-drainage layer realizes sludge-water separation of the downward subsurface flow constructed wetland, sludge is gradually precipitated at the bottom, and purified water after sludge removal is discharged out of the constructed wetland so as to ensure that the quality of effluent is better.

Description

Technical Field

[0001] The invention relates to the field of downward submerged flow artificial wetlands, and in particular to a downward submerged flow artificial wetland mud discharge system. Background Art

[0002] Subsurface flow artificial wetlands are widely used in the treatment of slightly polluted water bodies due to their small footprint, high pollutant removal rate and good landscape effects. Subsurface flow artificial wetlands are divided into horizontal subsurface flow artificial wetlands and vertical subsurface flow artificial wetlands. Among them, vertical flow artificial wetlands are divided into downward subsurface flow artificial wetlands and upward subsurface flow artificial wetlands according to the direction of water flow. Downward subsurface flow artificial wetlands have been widely used in sewage treatment plant tailwater treatment and other application scenarios in recent years due to their good reoxygenation conditions and high pollutant removal rate. Phosphorus removal pathways in artificial wetlands include plant absorption, filler adsorption, and microbial degradation. The absorption capacity of plants is very limited, and after the filler is saturated with adsorption, the adsorption rate drops significantly, and phosphorus may even be desorbed into the wetland system. Therefore, microbial phosphorus removal has a significant impact on the phosphorus removal efficiency of the entire wetland system. Microbial phosphorus removal generally removes phosphorus from the system by sludge discharge. After 1-2 years of operation, the downward subsurface flow artificial wetland has no sludge discharge project, which causes sludge to accumulate at the bottom of the wetland system, causing the total phosphorus concentration in the effluent to exceed the standard, and then causing the total phosphorus in the receiving water body to exceed the standard, and even causing outbreaks of blue-green algae and green algae, seriously affecting the water ecological safety of the basin. Sludge discharge can not only remove total phosphorus pollutants in the wetland system, but also relieve wetland blockage and extend the service life of the subsurface flow artificial wetland.

[0003] The invention patent entitled "A subsurface artificial wetland with anti-clogging and drainage construction and its operation method" describes a sludge collection method for a horizontal subsurface artificial wetland. The sludge collecting pipe is in a vertical direction, and multiple control valves are used to control the sludge discharge system. The sludge discharge capacity is small and the operation is complicated.

[0004] The utility model patent entitled "A non-clogging artificial wetland system and its sludge discharge time" describes a sludge collection method for an ascending subsurface flow artificial wetland. The sludge collecting pipe is located at the bottom of the entire wetland system. Water enters the wetland from the bottom of the system and flows out from the top. The water flows from bottom to top. The sludge collecting pipe is placed below the water inlet pipe. On the one hand, it is difficult to collect the sludge produced by the biological reaction in the wetland. On the other hand, the sludge must pass through the water inlet pipe before entering the sludge discharge ditch. There is a possibility of clogging the water inlet pipe and causing pollutants to re-enter the artificial wetland.

[0005] The above two patents seek mud discharge methods and measures from the perspectives of horizontal subsurface flow artificial wetlands and upward subsurface flow artificial wetlands respectively. There are certain drawbacks in the operation level. At present, there is no patent related to the mud discharge scheme of downward subsurface flow artificial wetlands. Summary of the invention

[0006] The technical problem to be solved by the present invention is to provide a downward submerged flow artificial wetland mud discharge system to overcome the deficiencies in the above-mentioned prior art.

[0007] The technical solution of the present invention to solve the above technical problems is as follows: a downward subsurface flow artificial wetland mud drainage system, comprising a planting layer, a water distribution pipe, a filler layer and a reverse osmosis layer arranged in sequence from top to bottom, and a mud collection-drainage layer for mud-water separation is arranged below the reverse osmosis layer.

[0008] Based on the above technical solution, the present invention can also be improved as follows.

[0009] Furthermore, the mud collection-drainage layer includes: a drainage grate arranged below the reverse osmosis layer, a plurality of diversion devices arranged side by side along the drainage direction on the cushion layer below the drainage grate, and mud drainage channels are formed between two adjacent diversion devices and between the diversion devices and the outer wall of the artificial wetland.

[0010] Furthermore, the diversion device includes: an inclined plate arranged along the drainage direction, the inclined plate is high in the middle and low on both sides, at least two vertical plates are arranged below the inclined plate along its length direction, a drainage channel is formed between two adjacent vertical plates, the upper end of the vertical plate is connected to the inclined plate, and a plurality of water inlets are provided at the junction of the vertical plate and the inclined plate, and the water inlets are higher than the edges on both sides of the inclined plate; the lower end of the vertical plate is connected to the cushion layer.

[0011] Furthermore, the mud collection-drainage layer also includes: a wall, a plurality of walls are arranged on the cushion layer along the drainage direction to support the drainage grates, the wall and the vertical plate have the same length, the diversion device and the wall are distributed alternately, and a mud discharge channel is formed between the wall and the diversion device.

[0012] Furthermore, the angles between the two sides of the inclined plate and the vertical direction are 45°-60°, and the water-facing surface of the inclined plate is made of a smooth plastic plate with a small friction coefficient.

[0013] Furthermore, the cushion layer is inclined downward along the length direction of the wall, and an inspection well is arranged on the outer side of the lower end of the cushion layer. The bottom of the inspection well is lower than the cushion layer, and the mud discharge channel is connected with the inspection well.

[0014] Furthermore, the mud collection and drainage layer also includes: a mud discharge plate arranged in the mud discharge channel, and a power mechanism for driving the mud discharge plate to move in the mud discharge channel to scrape the bottom mud in the mud discharge channel into the inspection well, and the wall and the vertical plate are distributed in parallel; the height of the mud discharge plate is lower than the height of the water inlet on the vertical plate, and the water filter holes are evenly distributed on the mud discharge plate.

[0015] Furthermore, the power mechanism includes: two supporting walls arranged in parallel along the length direction of the mud discharge channel and respectively attached to the wall and the vertical plate, the length of the supporting wall is the same as the length of the wall and the vertical plate, and the height of the supporting wall is lower than the height of the water inlet on the vertical plate; movable rollers are arranged on the top of each supporting wall, and tracks are respectively arranged on the sides of the wall and the vertical plate along the length direction of the supporting wall, and the fixed nodes in the tracks are connected to the central bearings of the rollers through connecting shafts, and the fixed nodes are connected to one end of the connecting rod, and the other end of the connecting rod is connected to the upper end of the mud discharge plate through a loose-leaf, and the mud discharge plate can be flipped forward and backward along its moving direction around the loose-leaf; the power mechanism also includes: two sets of first traction mechanisms and one set of second traction mechanism;

[0016] During mud discharge, the mud discharge plate is in a vertical state in the mud discharge channel, and the first traction mechanism and the second traction mechanism cooperate to drive the mud discharge plate to move in the mud discharge channel in a vertical state toward the inspection well and complete a single mud discharge; after the single mud discharge action is completed, the mud discharge plate is driven by the second traction mechanism to move so that the mud discharge plate is flipped from a vertical state to a horizontal state; the first traction mechanism and the second traction mechanism cooperate again to return the mud discharge plate to the origin in a horizontal state, and after the mud discharge plate returns to the origin, the second traction mechanism is used to adjust the mud discharge plate from a horizontal state to a vertical state.

[0017] Furthermore, the track includes: a support rod, a guide groove is opened on the wall or vertical board along the moving direction of its roller, the support rod is a T-shaped rod, the T-shaped end of the support rod is slidably matched with the guide groove, a movable ball is provided between the T-shaped end of the support rod and the guide groove, the support rod is connected to the fixed node, and the fixed node is connected to the center bearing of the roller through a connecting shaft.

[0018] Furthermore, an inspection well is provided on the outside of the higher end of the cushion layer, and a hinged door is provided in the area overlapping with the mud collecting-drainage layer. A glass liquid level observation window is vertically provided on the wall of the inspection well in the area overlapping with the filler layer.

[0019] The beneficial effects of the present invention are:

[0020] 1) The water distribution pipe evenly distributes the slightly polluted water on the packing layer, and after being treated by the packing layer, it flows to the reverse osmosis layer, and the sewage flowing out of the reverse osmosis layer enters the sludge collection-drainage layer. The reverse osmosis layer can filter out large-size fillers to prevent large-size fillers from falling into the sludge collection-drainage layer, playing a reverse filtration role, thereby preventing the sludge collection-drainage layer from being blocked to a certain extent. The sludge collection-drainage layer then separates the mud and water of the downward subsurface artificial wetland, and the sludge gradually settles at the bottom, while the purified water after mud removal is discharged from the artificial wetland to ensure better effluent water quality;

[0021] 2) The drainage grates in the mud collection-drainage layer are used to support the planting layer, water distribution pipes, filler layer and reverse osmosis layer on the one hand, and can prevent large-size fillers from falling down when sewage passes through. Microbial sludge, particulate matter, suspended solids and other sludge are gradually deposited in the mud discharge channel, forming bottom mud in the mud discharge channel. Purified water enters the drainage channel after passing through the water inlet, and uses gravity and hydrodynamic principles to achieve mud and water separation. It does not consume energy, does not produce any pollutants, and has better effluent quality. The normal operation of the submerged flow artificial wetland does not require additional power. Only a small amount of power is required during mud discharge and backwashing, which will greatly help the downward submerged flow artificial wetland to reduce carbon emissions, improve quality and increase efficiency, that is, clean and pollution-free, low-power operation;

[0022] 3) When the effluent volume decreases and the water quality deteriorates significantly, the sludge collection-drainage layer is maintained by backwashing. The sludge discharge channel, drainage channel, and diversion device are the parts where sludge is more likely to accumulate. Through backwashing, the blocked pollutants can be discharged from the wetland through the sludge discharge channel through the water flow, eliminating the risk of clogging of the sludge collection-drainage layer, ensuring the normal sludge collection, sludge discharge, water collection, and drainage functions of the sludge collection-drainage layer, ensuring the normal operation of the wetland and the water quality reaching the standard. The sludge discharge channel and drainage channel have a certain durability through backwashing. In addition, the overall height of the entire sludge collection-drainage layer is generally 25cm-35cm, which is slightly larger than that of the conventional drainage layer. However, since the entire system occupies a large area and has good stability, the fine sand buffer layer can be omitted, so that the height of the entire downward subsurface flow artificial wetland is equivalent to the conventional height and does not occupy additional land;

[0023] 4) The wall in the mud collection-drainage layer can reduce the pressure load and construction difficulty of the drainage grate, ensuring the safe and effective operation of the artificial wetland. The angle between the two sides of the inclined plate and the vertical direction is 45°-60°, and the water-facing surface of the inclined plate adopts a smooth plastic plate with a small friction coefficient, which makes it easier for the sludge falling on the inclined plate to slide into the mud discharge channel;

[0024] 5) Since the cushion layer is inclined downward along the length of the wall and the bottom of the inspection well is lower than the cushion layer, it is convenient to collect the sludge in the sludge discharge channel and prevent the sludge from flowing back into the sludge discharge channel. The sludge collection in the sludge discharge channel is checked regularly through the inspection well to discharge the collected sludge in time. By collecting the sludge and discharging it regularly, the blockage of the wetland is alleviated and the service life of the wetland is extended. In addition, the cushion layer is inclined downward along the length of the wall, and the purified water entering the drainage channel is also convenient for external discharge;

[0025] 6) After a certain thickness of bottom mud is deposited in the mud discharge channel, the mud discharge plate is driven by a power mechanism to move in the mud discharge channel to scrape the bottom mud with low water content in the mud discharge channel into the inspection well. The sludge in the inspection well can be discharged by a mud discharge pump, and then the bottom mud with high water content is pumped out by a special pump. Finally, the mud discharge channel is backwashed regularly to relieve the blockage of the water outlet, and the bottom mud that is difficult to be discharged by the above-mentioned mud discharge pump and special pump (such as walls, bottom of mud discharge channel, corners, etc.) is discharged by backwashing dilution. Multiple measures are taken simultaneously to ensure high mud discharge efficiency, timely discharge of wetland bottom mud, effectively alleviate wetland blockage, and allow a certain distance between the highest point of the mud discharge plate and the water inlet to ensure that the sludge will not enter the drainage channel through the water inlet. In addition, the filter holes are evenly distributed on the mud discharge plate to filter out muddy water with high water content and reduce the movement resistance of the mud discharge plate at the same time;

[0026] 7) A loose-leaf door is set in the area where the inspection well overlaps with the mud collection-drainage layer. It is usually closed. When the fixed pulley needs to be replaced, the loose-leaf door is opened to replace the internal fixed pulley; the liquid level of the downward submerged artificial wetland can be seen through the glass liquid level observation window, and the blockage status of the artificial wetland can be known through the rise and fall of the liquid level and the speed of the rise and fall, so that the bed can be stopped for renovation or mud discharge in time, providing a favorable reference for the time of stopping the bed for renovation and mud discharge, so that the submerged artificial wetland can operate normally and avoid blockage and a decrease in pollutant removal rate;

[0027] 8) The initial investment cost is slightly higher than that of conventional downward submerged flow artificial wetlands, but the excellent mud-water separation, mud discharge and backwashing functions of the mud collection-drainage layer can ensure better effluent water quality, greatly reduce the probability of wetland blockage, provide better engineering quality, and solve the operation and maintenance costs. In the long run, the cost is lower than that of conventional downward submerged flow artificial wetlands, and it is cost-effective. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a cross-sectional view of the downward subsurface flow artificial wetland mud discharge system of the present invention;

[0029] Figure 2 A top view of the mud collection-drainage layer of the present invention;

[0030] Figure 3 A side view of the mud collection-drainage layer of the present invention;

[0031] Figure 4 It is a front view of the diversion device of the present invention;

[0032] Figure 5 A purified water flow diagram of the diversion device of the present invention;

[0033] Figure 6 It is a structural diagram of the mud-discharging plate and the power mechanism of the present invention;

[0034] Figure 7 for Figure 6 A partial enlarged view of .

[0035] In the accompanying drawings, the components represented by the reference numerals are listed as follows:

[0036] 1. Planting layer, 2. Water distribution pipe, 3. Filling layer, 4. Reverse osmosis layer, 5. Mud collection and drainage layer, 510. Cushion layer, 520. Wall, 530. Diversion device, 531. Inclined plate, 532. Vertical plate, 533. Water inlet, 534. Drainage channel, 540. Drainage grate, 550. Mud discharge plate, 551. Water filter hole, 560. Power mechanism, 561. Support wall, 562. Roller, 563. Support rod, 564. Connecting rod, 565. Connecting shaft, 566. Fixed node, 567. Guide rail groove, 568. Movable ball, 569. Second fixed pulley, 570. Mud discharge channel, 6. Inspection well, 7. Maintenance well, 710. Glass liquid level observation window. DETAILED DESCRIPTION

[0037] The principles and features of the present invention are described below in conjunction with the accompanying drawings. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention.

[0038] Example 1

[0039] like Figure 1 As shown, a downward subsurface flow artificial wetland mud drainage system comprises a planting layer 1, a water distribution pipe 2, a filler layer 3 and a reverse osmosis layer 4 arranged in sequence from top to bottom. Aquatic plants can be planted on the planting layer 1, and a mud collection-drainage layer 5 for mud-water separation is arranged below the reverse osmosis layer 4;

[0040] The water distribution pipe 2 evenly distributes the slightly polluted water on the packing layer 3. After being treated by the packing layer 3, the water flows to the reverse osmosis layer 4, and the sewage flowing out of the reverse osmosis layer 4 enters the sludge collecting-drainage layer 5. The reverse osmosis layer 4 can filter out large-particle fillers to prevent the large-particle fillers from falling into the sludge collecting-drainage layer 5, thereby playing a reverse filtration role, thereby preventing the sludge collecting-drainage layer 5 from being blocked to a certain extent. The sludge collecting-drainage layer 5 can realize the separation of mud and water in the downward submerged flow artificial wetland, and the sludge gradually settles at the bottom, while the purified water after mud removal is discharged from the artificial wetland.

[0041] Example 2

[0042] like Figure 2 , Figure 3 As shown, this embodiment is a further improvement on the basis of embodiment 1, and the details are as follows:

[0043] The mud collection-drainage layer 5 includes: a diverter device 530 and a drainage grate 540. The drainage grate 540 is arranged below the reverse osmosis layer 4. A plurality of diverter devices 530 are arranged side by side along the drainage direction on the cushion layer 510 below the drainage grate 540. A mud discharge channel 570 is formed between two adjacent diverter devices 530 and between the diverter device 530 and the outer wall of the artificial wetland. The drainage grate 540 is used to support the planting layer 1, the water distribution pipe 2, the filler layer 3 and the reverse osmosis layer 4 on the one hand, and can prevent large-particle fillers from falling down on the other hand. The diverter device 530 separates the sludge from the water, and the sludge is gradually settled in the mud discharge channel 570, and the separated purified water is discharged from the artificial wetland through the diverter device 530.

[0044] In this embodiment, the drainage grate 540 is made of parallel and densely distributed hard plastic or steel bars with high strength.

[0045] Example 3

[0046] like Figure 3 , Figure 4 , Figure 5 As shown, this embodiment is a further improvement on the basis of embodiment 2, and the details are as follows:

[0047] The diverter device 530 includes: an inclined plate 531 and a vertical plate 532. The inclined plate 531 is arranged on the cushion layer 510 along the drainage direction. The inclined plate 531 is high in the middle and low on both sides. At least two vertical plates 532 are arranged below the inclined plate 531 along its length direction. A drainage channel 534 is formed between two adjacent vertical plates 532. The upper ends of the vertical plates 532 are connected to the inclined plates 531. There are multiple water inlets 533 at the junction of the vertical plates 532 and the inclined plates 531. The water inlets 533 are higher than the edges on both sides of the inclined plates 531. After the sewage passes through the drainage grate 540, the microbial debris, particulate matter, suspended solids and other sludge therein are gradually deposited in the sludge discharge channel 570 to form bottom sludge in the sludge discharge channel 570. The purified water enters the drainage channel 534 after passing through the water inlet 533. The diverter device 530 separates water and sludge while draining.

[0048] When the water inlet 533 and the drainage channel 534 are blocked, the water intake of the artificial wetland is stopped, and the clean water is pumped back into the drainage channel 534 with the help of a water pump, and then enters the mud discharge channel 570 through the water inlet 533 to backwash the sludge that may exist in the drainage channel 534, the accumulated bottom mud that is difficult to discharge from the mud discharge channel 570, and the sludge adhered to the diversion device 530, and the sludge is backwashed to the mud discharge channel 570, and then the sewage containing the sludge is discharged through the mud discharge channel 570 to eliminate the possible siltation problem of the mud collection-drainage layer 5.

[0049] Example 4

[0050] like Figure 2As shown, this embodiment is a further improvement on the basis of Embodiment 2 or 3, and the details are as follows:

[0051] The mud collection-drainage layer 5 also includes: a wall 520, a plurality of walls 520 are arranged on the cushion layer 510 along the drainage direction to support the drainage grate 540, the wall 520 is the same length as the vertical plate 532, the diverter device 530 and the wall 520 are alternately distributed, and a mud discharge channel 570 is formed between the wall 520 and the diverter device 530. The wall 520 can reduce the pressure load and construction difficulty of the drainage grate 540 to ensure the safe and effective operation of the artificial wetland. The wall 520 can be made of reinforced concrete.

[0052] Example 5

[0053] like Figure 3 As shown, this embodiment is a further improvement on the basis of Embodiment 3 or 4, and the details are as follows:

[0054] The angles between the two sides of the inclined plate 531 and the vertical direction are 45°-60°. The water-facing surface of the inclined plate 531 is made of a smooth plastic plate with a small friction coefficient, which facilitates the sludge falling on the inclined plate 531 to slide into the sludge discharge channel 570.

[0055] Example 6

[0056] like Figure 4 As shown, this embodiment is a further improvement on the basis of Embodiment 5, and the details are as follows:

[0057] The cushion layer 510 is inclined downward along the length direction of the wall 520, and an inspection well 6 is provided on the outer side of the lower end of the cushion layer 510. The bottom of the inspection well 6 is lower than the cushion layer 510, and the mud discharge channel 570 is connected with the inspection well 6. Since the cushion layer 510 is inclined downward along the length direction of the wall 520, and the bottom of the inspection well 6 is lower than the cushion layer 510, it is convenient to collect the sludge in the mud discharge channel 570, and the sludge can be prevented from flowing back into the mud discharge channel 570. The mud collection condition of the mud discharge channel can be checked regularly through the inspection well 6, and the mud can be discharged in time, or When the effluent volume decreases and the water quality deteriorates significantly, the maintenance of the sludge collection and drainage layer 5 is achieved through backwashing, which can effectively solve the problem of the water quality deteriorating due to the inability to discharge sludge in the downward submerged flow artificial wetland. The integrated sludge discharge and drainage can effectively separate the sludge and water, making the effluent water quality better and effectively solving the wetland blockage problem. By collecting sludge and discharging it regularly, the wetland blockage can be alleviated and the service life of the wetland can be extended. In addition, the cushion layer 510 is inclined downward along the length direction of the wall 520, and the purified water entering the drainage channel 534 is also convenient for discharge.

[0058] Example 7

[0059] like Figure 6As shown, this embodiment is a further improvement on the basis of Embodiment 6, and the details are as follows:

[0060] The mud collecting and drainage layer 5 also includes: a mud discharge plate 550 and a power mechanism 560. The mud discharge plate 550 is arranged in the mud discharge channel 570. The wall 520 and the vertical plate 532 are arranged in parallel. The power mechanism 560 is used to drive the mud discharge plate 550 to move in the mud discharge channel 570 to scrape the bottom mud in the mud discharge channel 570 into the inspection well 6. After a certain thickness of bottom mud is deposited in the mud discharge channel 570, the mud discharge plate 550 is driven by the power mechanism 560 to move in the mud discharge channel 570 to scrape the bottom mud with a low water content in the mud discharge channel 570 into the inspection well 6. The sludge in the inspection well 6 can be discharged by a mud discharge pump, and then the bottom mud with a high water content is pumped out by a special pump. Finally, the mud discharge is regularly pumped out. The channel 570 is backwashed to relieve the blockage of the water outlet, and the bottom sludge that is difficult to be discharged by the above-mentioned sludge pump and special pump (such as walls, the bottom of the sludge channel, corners, etc.) is diluted and discharged through backwashing. The height of the sludge discharge plate 550 is lower than the height of the water inlet 533 on the vertical plate 532. Normally, the height of the sludge discharge plate 550 is 1 / 2-2 / 3 of the height of the vertical plate 532, so that there is a certain distance between the highest point of the sludge discharge plate 550 and the water inlet 533 to ensure that the sludge does not enter the drainage channel 534 through the water inlet 533. Furthermore: the water filter holes 551 are evenly distributed on the sludge discharge plate 550, which can filter out muddy water with a higher water content and reduce the movement resistance of the sludge discharge plate 550.

[0061] Example 8

[0062] like Figure 6 , Figure 7 As shown, this embodiment is a further improvement on the basis of Embodiment 7, and the details are as follows:

[0063] The power mechanism 560 includes: two support walls 561 arranged along the length direction of the wall 520 and respectively close to the wall 520 and the vertical plate 532, the length of the support wall 561 is the same as the length of the wall 520, the length of the support wall 561 is the same as the length of the vertical plate 532, and the height of the support wall 561 is lower than the height of the water inlet 533 on the vertical plate 532;

[0064] A movable roller 562 is arranged on the top of each supporting wall 561, and tracks are respectively arranged on the sides of the wall 520 and the vertical plate 532 along the length direction of the supporting wall 561. The fixed node 566 in the track is connected to the central bearing of the roller 562 through the connecting shaft 565, and the fixed node 566 is connected to one end of the connecting rod 564. The other end of the connecting rod 564 is connected to the upper end of the mud discharge plate 550 through a hinge. The mud discharge plate 550 can be flipped forward and backward along its moving direction around the hinge.

[0065] The power mechanism 560 also includes: two sets of first traction mechanisms and second traction mechanisms;

[0066] When discharging mud, the mud discharging plate 550 is in a vertical state in the mud discharging channel 570, and the first traction mechanism and the second traction mechanism cooperate to drive the mud discharging plate 550 to move in the mud discharging channel 570 in a vertical state toward the inspection well 6 and complete a single mud discharging;

[0067] After a single mud discharge action is completed, the mud discharge plate 550 is driven by the second traction mechanism to turn the mud discharge plate 550 from a vertical state to a horizontal state;

[0068] The first traction mechanism and the second traction mechanism cooperate to make the mud discharge plate 550 return to the origin in a horizontal state, and after the mud discharge plate 550 returns to the origin, the mud discharge plate 550 is adjusted from the horizontal state to the vertical state by the second traction mechanism. In this embodiment, the mud discharge plate 550 returns to the origin in a horizontal state to avoid the resistance of the mud and water in the mud discharge channel 570 to the mud discharge plate 550;

[0069] Continue to repeat the mud discharge until the bottom mud with lower water content is discharged into the inspection well 6, and the remaining mud with higher water content can be directly pumped out with a special pump.

[0070] Further:

[0071] The track includes: a support rod 563, a guide groove 567 is provided on the wall 520 or the vertical plate 532 along the moving direction of the roller 562, the support rod 563 is a T-shaped rod, and the T-shaped end of the support rod 563 is slidably matched with the guide groove 567, that is, the T-shaped end of the support rod 563 can reciprocate in the guide groove 567 along the length direction of the guide groove 567;

[0072] In addition, a movable ball 568 is provided between the T-shaped end of the support rod 563 and the guide groove 567. When the T-shaped end of the support rod 563 moves in the guide groove 567, the movable ball 568 moves along the inner wall of the guide groove 567. The movable ball 568 can reduce the friction between the T-shaped end of the support rod 563 and the guide groove 567, and the pressure on the movable ball 568 during the movement can act on the inner wall of the guide groove 567, so that the weight of the mud discharge plate 550 and the force of the mud acting on the mud discharge plate 550 can be supported.

[0073] A groove for accommodating the movable ball 568 is provided on the T-shaped end of the support rod 563, and the movable ball 568 can be limited by the groove to prevent it from being separated from the T-shaped end of the support rod 563;

[0074] The support rod 563 is connected to the fixed node 566 , and the fixed node 566 is connected to the central bearing of the roller 562 via the connecting shaft 565 .

[0075] The first traction mechanism includes: a first fixed pulley, a first rope and a first traction motor, one end of the first rope is connected to a support rod 563 in one of the tracks, and the other end is connected to the first traction motor after passing through the first fixed pulley fixed to the front end of the mud collecting-drainage layer 5, and the front end of the mud collecting-drainage layer 5 is the end away from the inspection well 6;

[0076] The second traction mechanism includes: a second fixed pulley 569, a second rope and a second traction motor. The second fixed pulley 569 is arranged in the middle position of the lower end of the mud discharge plate 550. The second traction motor drives the mud discharge plate 550 to flip back and forth along the moving direction of the movable leaf around the second rope. The first rope and the second rope are both made of ropes with high strength and toughness, such as polypropylene or thin steel wire.

[0077] Example 10

[0078] like Figure 1 As shown, this embodiment is a further improvement on the basis of Embodiment 9, and the details are as follows:

[0079] A maintenance well 7 is provided on the outer side of the higher end of the cushion layer 510. A hinged door is provided at the area where the maintenance well 7 overlaps with the mud collecting-drainage layer 5. The hinged door is usually closed. When the fixed pulley needs to be replaced, the hinged door is opened to replace the internal fixed pulley.

[0080] A glass liquid level observation window 710 is vertically arranged on the wall of the inspection well 7 in the area overlapping with the packing layer 3. The width of the glass is 10-30 cm. The liquid level of the downward submerged flow artificial wetland can be seen through the glass liquid level observation window 710. The blockage condition of the artificial wetland can be known by the rise and fall of the liquid level and the speed of the rise and fall, so that the artificial wetland can be stopped for repair or mud discharge in time, which provides a favorable reference for the time of stopping the artificial wetland for repair and mud discharge, so that the submerged flow artificial wetland can operate normally and avoid blockage and a decrease in pollutant removal rate.

[0081] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A downward subsurface flow artificial wetland mud discharge system, characterized in that: It comprises a planting layer (1), a water distribution pipe (2), a filler layer (3) and a reverse osmosis layer (4) which are arranged in sequence from top to bottom, and a mud collection-drainage layer (5) for mud-water separation is arranged below the reverse osmosis layer (4).

2. A downward submerged flow artificial wetland mud discharge system according to claim 1, characterized in that: The mud collection and drainage layer (5) comprises: a drainage grate (540) arranged below the reverse osmosis layer (4); a plurality of diversion devices (530) are arranged side by side along the drainage direction on the cushion layer (510) below the drainage grate (540); and mud drainage channels (570) are formed between two adjacent diversion devices (530) and between the diversion devices (530) and the outer wall of the artificial wetland.

3. A downward submerged flow artificial wetland mud discharge system according to claim 1 or 2, characterized in that: The diversion device (530) comprises: an inclined plate (531) arranged along the drainage direction, the inclined plate (531) being high in the middle and low on both sides, at least two vertical plates (532) being arranged below the inclined plate (531) along its length direction, a drainage channel (534) being formed between two adjacent vertical plates (532), the upper end of the vertical plate (532) being connected to the inclined plate (531), a plurality of water inlets (533) being provided at the junction of the vertical plate (532) and the inclined plate (531), the water inlets (533) being higher than the edges on both sides of the inclined plate (531); and the lower end of the vertical plate (532) being connected to the cushion layer (510).

4. A downward submerged flow artificial wetland mud discharge system according to claim 1, 2 or 3, characterized in that: The mud collection and drainage layer (5) further comprises: a wall (520); a plurality of walls (520) are arranged on the cushion layer (510) along the drainage direction to support the drainage grate (540); the wall (520) and the vertical plate (532) have the same length; the diverter device (530) and the wall (520) are alternately distributed; and a mud drainage channel (570) is formed between the wall (520) and the diverter device (530).

5. The downward submerged flow artificial wetland mud discharge system according to claim 3, characterized in that: The angles between the two sides of the inclined plate (531) and the vertical direction are 45°-60°, and the water-facing surface of the inclined plate (531) is made of a smooth plastic plate with a small friction coefficient.

6. A downward submerged flow artificial wetland mud discharge system according to claim 4, characterized in that: The cushion layer (510) is inclined downward along the length direction of the wall (520), and an inspection well (6) is provided on the outer side of the lower end of the cushion layer (510). The bottom of the inspection well (6) is lower than the cushion layer (510), and the mud discharge channel (570) is connected to the inspection well (6).

7. A downward submerged flow artificial wetland mud discharge system according to claim 6, characterized in that: The mud collection and drainage layer (5) further comprises: a mud discharge plate (550) arranged in the mud discharge channel (570), and a power mechanism (560) for driving the mud discharge plate (550) to move in the mud discharge channel (570) so as to scrape the bottom mud in the mud discharge channel (570) into the inspection well (6); the wall (520) and the vertical plate (532) are arranged in parallel; the height of the mud discharge plate (550) is lower than the height of the water inlet (533) on the vertical plate (532); and the water filtering holes (551) are evenly distributed on the mud discharge plate (550).

8. A downward subsurface flow artificial wetland mud discharge system according to claim 7, characterized in that: The power mechanism (560) comprises: two supporting walls (561) arranged in parallel along the length direction of the mud discharge channel (570) and respectively close to the wall (520) and the vertical plate (532); the lengths of the supporting walls (561) are respectively the same as the lengths of the wall (520) and the vertical plate (532); the heights of the supporting walls (561) are lower than the heights of the water inlets (533) on the vertical plates (532); a movable roller (562) is arranged on the top of each supporting wall (561); the wall (520) and the vertical plate (532) are connected to the supporting walls (561) and the vertical plate (532) are connected to the supporting walls (561). Tracks are arranged on the side surfaces along the length direction of the supporting wall (561); a fixed node (566) in the track is connected to the central bearing of the roller (562) via a connecting shaft (565); the fixed node (566) is connected to one end of a connecting rod (564); the other end of the connecting rod (564) is connected to the upper end of the mud discharge plate (550) via a hinge; the mud discharge plate (550) can be flipped forward and backward along its moving direction around the hinge; the power mechanism (560) further comprises: two sets of first traction mechanisms and one set of second traction mechanism; During mud discharge, the mud discharge plate (550) is in a vertical state in the mud discharge channel (570), and the first traction mechanism and the second traction mechanism cooperate to drive the mud discharge plate (550) to move in a vertical state in the mud discharge channel (570) toward the inspection well (6) and complete a single mud discharge; after the single mud discharge action is completed, the mud discharge plate (550) is driven by the second traction mechanism to move so that the mud discharge plate (550) is flipped from a vertical state to a horizontal state; the first traction mechanism and the second traction mechanism cooperate to make the mud discharge plate (550) return to the origin in a horizontal state, and after the mud discharge plate (550) returns to the origin, the mud discharge plate (550) is adjusted from a horizontal state to a vertical state by the second traction mechanism.

9. A downward submerged flow artificial wetland mud discharge system according to claim 8, characterized in that: The track comprises: a support rod (563); a guide groove (567) is provided on the wall (520) or the vertical plate (532) along the moving direction of the roller (562); the support rod (563) is a T-shaped rod; the T-shaped end of the support rod (563) is slidably matched with the guide groove (567); a movable ball (568) is provided between the T-shaped end of the support rod (563) and the guide groove (567); the support rod (563) is connected to a fixed node (566); and the fixed node (566) is connected to the central bearing of the roller (562) via a connecting shaft (565).

10. A downward submerged flow artificial wetland mud discharge system according to claim 9, characterized in that: A maintenance well (7) is provided on the outer side of the higher end of the cushion layer (510), and a hinged door is provided on the maintenance well (7) in an area overlapping with the mud collecting and drainage layer (5), and a glass liquid level observation window (710) is vertically provided on the wall of the maintenance well (7) in an area overlapping with the filler layer (3).

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