Constructed wetland system for nitrogen and phosphorus removal treatment of sewage

Abstract

The utility model discloses a constructed wetland system for nitrogen and phosphorus removal treatment of sewage. The constructed wetland system comprises a primary sedimentation tank and a horizontal subsurface flow constructed wetland, the horizontal subsurface flow constructed wetland is of a pool-shaped structure, a water distribution channel for uniformly supplying water to the horizontal subsurface flow constructed wetland is arranged on the front side of the horizontal subsurface flow constructed wetland, a water collection channel for collecting water purified by the horizontal subsurface flow constructed wetland is arranged on the rear side of the horizontal subsurface flow constructed wetland, and the water distribution channel is connected with the primary sedimentation tank through a connecting pipe; a water inlet pipe is arranged on the primary sedimentation tank, the horizontal subsurface flow constructed wetland is filled with three-section filler, the section close to the water distribution channel is a water inlet area, the section close to the water collection channel is a water outlet area, a main body area is arranged between the water inlet area and the water outlet area, and the filler in the main body area is pyrite particles with the particle size of 4-8mm; the device has the beneficial effects that water inflow is uniform, the utilization rate of constructed wetland resources can be increased, efficient nitrogen and phosphorus removal treatment can be carried out on sewage, and dual natural drop aeration can be realized.

Description

Technical Field

[0001] The utility model belongs to the technical field of sewage treatment, and particularly relates to an artificial wetland system for sewage denitrification and dephosphorization treatment. Background Art

[0002] As a typical ecological treatment technology, artificial wetlands have the advantages of low construction cost, low operating cost, simple operation and maintenance, and beautification of the environment, and are widely used in sewage treatment; however, in the face of increasingly stringent environmental protection requirements, the treatment effect of artificial wetlands needs to be further improved; the Chinese utility model patent with publication number CN215975424U discloses an artificial wetland device, including a shell, a plant planting area, a fine sand layer, a gravel layer, a supporting layer, a water distribution layer, and a suction cup; the plant planting area, the fine sand layer, the gravel layer, the supporting layer, and the water distribution layer are arranged in the shell from top to bottom, the upper side of the shell is provided with a water inlet pipe, and the bottom of the shell is provided with a water outlet pipe; the suction cup is arranged on the bottom surface of the shell. The above-mentioned scheme provided by the present application is arranged in the shell as a whole, occupies a small area, and each shell is provided with a suction cup.

[0003] The water inlet position in the above-mentioned comparative document only uses an inlet pipe to supply sewage, resulting in a large water flow near the inlet pipe in the wetland, and a small water flow far away from the inlet pipe. The uneven water inlet will cause the wetland components near the inlet pipe to work overloaded, while the wetland components far away from the inlet pipe fail to play their full role, resulting in a certain amount of resource waste. Moreover, the filler in the above-mentioned comparative document only relies on human filtration and cannot perform a more direct sewage denitrification effect on sewage, resulting in too low sewage denitrification efficiency. Utility Model Content

[0004] The utility model aims to provide an artificial wetland system for sewage denitrification and phosphorus removal, so as to solve the technical problems in the above-mentioned background technology that sewage inflow is uneven, resulting in waste of resources and low sewage denitrification efficiency.

[0005] The above technical objectives of the utility model are achieved through the following technical solutions:

[0006] A sewage denitrification and dephosphorization artificial wetland system comprises: a primary sedimentation tank and a horizontal subsurface flow artificial wetland; the horizontal subsurface flow artificial wetland is a pool-shaped structure, a water distribution channel for uniformly supplying water to the horizontal subsurface flow artificial wetland is provided at the front side of the horizontal subsurface flow artificial wetland, a water collection channel for collecting water purified by the horizontal subsurface flow artificial wetland is provided at the rear side of the horizontal subsurface flow artificial wetland, the water distribution channel is connected to the primary sedimentation tank through a connecting pipe, a water inlet pipe is provided on the primary sedimentation tank, and the horizontal subsurface flow artificial wetland is filled with three-section fillers, wherein a section close to the water distribution channel is a water inlet area, a section close to the water collection channel is a water outlet area, a main area is set between the water inlet area and the water outlet area, and the filler in the main area is pyrite particles with a particle size of 4-8mm.

[0007] Furthermore, in order to enable the water in the horizontal subsurface flow artificial wetland to flow naturally, the bottom of the horizontal subsurface flow artificial wetland is configured as an inclined slope, and the height of the inclined slope on the distribution channel side is higher than the height on the collection channel side.

[0008] Furthermore, in order to prevent the utility model from being overloaded and blocked, two primary sedimentation tanks are provided, one for use and one for backup.

[0009] Furthermore, in order to enable the primary sedimentation tank to effectively carry out preliminary sedimentation of suspended matter in the water, the water inlet pipe is connected to the downpipe through a right-angle bend above the primary sedimentation tank, and the downpipe is inserted into the vicinity of the bottom of the primary sedimentation tank. An overflow port is provided on the top of the side of the primary sedimentation tank, and the overflow port is connected to the connecting pipe. The water inlet pipe is fixed at the center of the primary sedimentation tank with a fixed pipe plate of a plate structure.

[0010] Furthermore, in order to form natural waterfall aeration when water flows into the water inlet area, a strip opening or a linear array opening is provided on one side of the water distribution channel close to the water inlet area to form a water distribution hole, the bottom height of the water distribution hole is 20-30 cm higher than the filler in the water inlet area, and the pipe opening connecting the connecting pipe to the water distribution channel is 20-30 cm higher than the water distribution hole 7.

[0011] Furthermore, in order to provide an attachment environment for biochemical filtration microorganisms in the water inlet and outlet areas, the fillers in the water inlet and outlet areas are one or more of limestone, volcanic rock, zeolite, shale, slag and anthracite, and the filler particle size is controlled between 10-15 mm.

[0012] Furthermore, in order to further absorb pollutants in the horizontal subsurface flow artificial wetland, emergent plants are planted above the water inlet area, the main area, and the water outlet area. The emergent plants are one or more of reeds, cattails, calamus, cannas, and lilies.

[0013] Furthermore, in order to facilitate the cleaning of impurities in the primary sedimentation tank, the primary sedimentation tank is elevated by a bracket, and an opening is provided at the bottom of the primary sedimentation tank to form a sewage outlet. The sewage outlet is connected to a control valve through a pipeline, and the sludge settled in the primary sedimentation tank can be discharged by opening the control valve.

[0014] In summary, the utility model has the following beneficial effects:

[0015] 1. The water inlet is uniform, which can improve the utilization rate of artificial wetland resources: through the establishment of water distribution channels, water distribution holes and slopes, the clear liquid after sedimentation enters the connecting pipe from the overflow port of the primary sedimentation tank, and is transported to the water distribution channel by the connecting pipe. The water distribution holes on the water distribution channel distribute the water flow evenly to the water inlet area by means of waterfall aeration, making the water flow in the artificial wetland relatively stable and uniform, thereby increasing the utilization rate of artificial wetland resources.

[0016] 2. It can carry out efficient denitrification and phosphorus removal treatment for sewage; through the establishment of the main area, the main area is filled with pyrite particles. The main component of pyrite is FeS2, which can use reducing sulfur compounds as electron donors to reduce nitrates to nitrogen gas without the need for an external carbon source; on the other hand, the Fe+ released by the wetland during the autotrophic denitrification process can react with PO43- in the tail water to generate FePO4, thereby removing phosphorus and achieving better denitrification and phosphorus removal effects on the tail water.

[0017] 3. Double natural waterfall aeration: Because the bottom height of the water distribution hole is 20-30cm higher than the filler in the water inlet area, and the pipe mouth connecting the connecting pipe and the water distribution channel is 20-30cm higher than the water distribution hole 7, the water flow will fall from a high place twice under the action of gravity and the two height differences. Due to the water flow drop, the water flow has a certain dynamic potential energy before contacting the next level of water body. After the falling water flow contacts the lower water body, the water flow energy is transferred to the water body. As a result, the receiving water body receives the energy and the flow state changes from laminar flow to turbulent flow. The liquid surface is stirred and air is drawn in for oxygenation. At the same time, the continuous stirring of the liquid surface continuously updates the gas-liquid contact surface, which is conducive to the continuous transfer of oxygen to the water body. Therefore, efficient and low-consumption sewage oxygenation can be achieved to form double natural waterfall aeration. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of the overall structure of the utility model;

[0019] Figure 2 This is a schematic diagram of the purification principle structure of the utility model;

[0020] Figure 3 It is a schematic diagram of the internal structure of the primary sedimentation tank 1 in the utility model;

[0021] In the figure, 1. primary sedimentation tank; 2. horizontal subsurface flow artificial wetland; 3. connecting pipe; 4. water inlet pipe; 5. distribution channel; 6. water collection channel; 7. water distribution hole; 8. water inlet area; 9. main area; 10. water outlet area; 11. emergent plants; 12. outlet pipe; 13. sewage outlet; 14. fixed pipe plate; 15. overflow outlet; 21. inclined slope; 41. right-angle bend; 42. downpipe. DETAILED DESCRIPTION

[0022] The utility model is further described in detail below in conjunction with the accompanying drawings.

[0023] Example:

[0024] See also Figure 1-Figure 3The utility model provides a technical solution: an artificial wetland system for sewage denitrification and phosphorus removal, comprising: a primary sedimentation tank 1, a horizontal subsurface flow artificial wetland 2; the horizontal subsurface flow artificial wetland 2 is a pool-shaped structure, a water distribution channel 5 for uniformly supplying water to the horizontal subsurface flow artificial wetland 2 is provided on the front side of the horizontal subsurface flow artificial wetland 2, a water collection channel 6 for collecting water purified by the horizontal subsurface flow artificial wetland 2 is provided on the rear side of the horizontal subsurface flow artificial wetland 2, the water distribution channel 5 is connected to the primary sedimentation tank 1 through a connecting pipe 3, a water inlet pipe 4 is provided on the primary sedimentation tank 1, and the horizontal subsurface flow artificial wetland 2 is filled with three-section fillers, wherein a section close to the water distribution channel 5 is a water inlet area 8, a section close to the water collection channel 6 is a water outlet area 10, a main area 9 is set between the water inlet area 8 and the water outlet area 10, and the filler in the main area 9 is pyrite particles with a particle size of 4-8mm.

[0025] In order to enable the water in the horizontal subsurface flow artificial wetland 2 to flow naturally, the bottom of the horizontal subsurface flow artificial wetland 2 is configured as an inclined slope 21 , and the height of the inclined slope 21 on the distribution channel 5 side is higher than that on the collection channel 6 side.

[0026] In order to prevent the utility model from being overloaded and blocked, two primary sedimentation tanks 1 are provided, one for use and one for backup.

[0027] In order to enable the primary sedimentation tank 1 to effectively carry out preliminary sedimentation of suspended matter in the water, the water inlet pipe 4 is connected to the downpipe 42 through a right-angle bend 41 above the primary sedimentation tank 1. The downpipe 42 penetrates into the vicinity of the bottom of the primary sedimentation tank 1. An overflow port 15 is provided on the top of the side of the primary sedimentation tank 1. The overflow port 15 is connected to the connecting pipe 3. The water inlet pipe 4 is fixed to the center position of the primary sedimentation tank 1 by a fixed pipe plate 14 with a plate-like structure.

[0028] In order to form natural waterfall aeration when water flows into the water inlet area 8, a strip opening or a linear array of openings is provided on one side of the water distribution channel 5 close to the water inlet area 8 to form a water distribution hole 7. The bottom height of the water distribution hole 7 is 20-30 cm higher than the filler in the water inlet area 8, and the pipe opening connecting the connecting pipe 3 and the water distribution channel 5 is 20-30 cm higher than the water distribution hole 7.

[0029] In order to provide an attachment environment for biochemical filtration microorganisms in the water inlet area 8 and the water outlet area 10, the fillers in the water inlet area 8 and the water outlet area 10 are one or more of limestone, volcanic rock, zeolite, shale, slag and anthracite, and the particle size of the filler is controlled between 10-15 mm.

[0030] In order to further absorb pollutants in the horizontal subsurface flow artificial wetland 2, emergent plants 11 are planted above the water inlet area 8, the main area 9, and the water outlet area 10. The emergent plants 11 are one or more of reeds, cattails, calamus, cannas, and lilies.

[0031] In order to facilitate the cleaning of impurities in the primary sedimentation tank 1, the primary sedimentation tank 1 is elevated by a bracket, and an opening is provided at the bottom of the primary sedimentation tank 1 to form a sewage outlet 13. The sewage outlet 13 is connected to a control valve through a pipeline, and the sludge settled in the primary sedimentation tank 1 can be discharged by opening the control valve.

[0032] When in use, the length and width of the pool of the horizontal submerged flow artificial wetland 2 are 3:1 to 10:1, and the hydraulic retention time of the submerged flow artificial wetland 2 is not less than 24 hours; the sewage enters the primary sedimentation tank 1 through the water inlet pipe 4, and the downpipe 42 is used to directly transport the heavier mud to the bottom of the primary sedimentation tank 1, and add flocculants. The sewage is precipitated in the primary sedimentation tank to remove suspended matter in the water. The precipitated suspended matter can be discharged by opening the valve at the sewage outlet 13, and the clear liquid after precipitation enters the connecting pipe 3 from the overflow port 15 of the primary sedimentation tank 1, and is transported to the water distribution channel 5 by the connecting pipe 3. The water distribution holes 7 on the water distribution channel 5 evenly distribute the water flow to the water inlet area 8 in the form of waterfall aeration, and the microorganisms in the filler of the water inlet area 8 perform preliminary biochemical filtration on the sewage. Then the water flow in the water inlet area 8 enters the main area 9 under the action of the inclined slope 21. Because the main area 9 is filled with pyrite particles, pyrite is mainly The composition is FeS2, which can use reducing sulfur compounds as electron donors on the one hand, and reduce nitrates to nitrogen gas without the need for an external carbon source; on the other hand, the Fe3+ released by the wetland during the autotrophic denitrification process can react with PO43- in the tail water to generate FePO4, thereby removing phosphorus and achieving better denitrification and phosphorus removal effects on the tail water; after denitrification and phosphorus removal in the main area 9, and then through the biochemical filtration of the filler in the outlet area 10, it enters the water collection channel 6 and is discharged from the outlet pipe 12 connected to the water collection channel 6; the primary sedimentation tank 1 is used in one and is reserved in the other. When the amount of sewage is too large, the two primary sedimentation tanks 1 can be started at the same time. The emergent plants 11 can absorb and adsorb pollutants in the water. They not only absorb dissolved pollutants, but also quickly absorb pollutants in suspended particles, and can transfer these particles into cells after absorption, thereby achieving the effect of treating both the symptoms and the root causes, so as to further purify the water quality.

[0033] This specific embodiment is merely an explanation of the present invention and is not a limitation of the present invention. After reading this specification, those skilled in the art may make non-creative modifications to the present embodiment as needed, but such modifications are protected by patent law as long as they are within the scope of the claims of the present invention.

Claims

1. A sewage denitrification and phosphorus removal artificial wetland system, comprising: A primary sedimentation tank (1) and a horizontal subsurface flow artificial wetland (2); characterized in that: the horizontal subsurface flow artificial wetland (2) is a pool-shaped structure, a water distribution channel (5) for uniformly supplying water to the horizontal subsurface flow artificial wetland (2) is provided on the front side of the horizontal subsurface flow artificial wetland (2), a water collection channel (6) for collecting water purified by the horizontal subsurface flow artificial wetland (2) is provided on the rear side of the horizontal subsurface flow artificial wetland (2), the water distribution channel (5) is connected to the primary sedimentation tank (1) through a connecting pipe (3), a water inlet pipe (4) is provided on the primary sedimentation tank (1), and the horizontal subsurface flow artificial wetland (2) is filled with three-section fillers, wherein a section close to the water distribution channel (5) is a water inlet area (8), and a section close to the water collection channel (6) is a water outlet area (10), and a main area (9) is set between the water inlet area (8) and the water outlet area (10), and the filler in the main area (9) is pyrite particles with a particle size of 4-8 mm.

2. The artificial wetland system for wastewater denitrification and phosphorus removal according to claim 1, characterized in that: The bottom of the horizontal subsurface flow artificial wetland (2) is arranged to be an inclined slope (21), and the height of the inclined slope (21) on the water distribution channel (5) side is higher than the height on the water collection channel (6) side.

3. The artificial wetland system for sewage denitrification and phosphorus removal according to claim 1 is characterized by: The primary sedimentation tanks (1) are provided with two in total, one for use and one for backup.

4. The artificial wetland system for wastewater denitrification and phosphorus removal according to claim 3 is characterized by: The water inlet pipe (4) is connected to a down-probe pipe (42) above the primary sedimentation tank (1) through a right-angle bend (41), and the down-probe pipe (42) protrudes to near the bottom of the primary sedimentation tank (1). An overflow port (15) is provided at the top of the side of the primary sedimentation tank (1), and the overflow port (15) is connected to the connecting pipe (3). The water inlet pipe (4) is fixed at the center position of the primary sedimentation tank (1) by a fixed tube plate (14) with a plate-like structure.

5. The artificial wetland system for sewage denitrification and phosphorus removal according to claim 1, characterized in that: The water distribution channel (5) is provided with strip openings or linear array openings on one side close to the water inlet area (8) to form a water distribution hole (7). The bottom height of the water distribution hole (7) is 20-30 cm higher than the filler in the water inlet area (8). The pipe opening of the connecting pipe (3) connected to the water distribution channel (5) is 20-30 cm higher than the water distribution hole (7).

6. The artificial wetland system for wastewater denitrification and phosphorus removal according to claim 1, characterized in that: The fillers in the water inlet area (8) and the water outlet area (10) are one or more of limestone, volcanic rock, zeolite, shale, slag and anthracite, and the particle size of the fillers is controlled between 10-15 mm.

7. The artificial wetland system for wastewater denitrification and phosphorus removal according to claim 6, characterized in that: Emergent plants (11) are planted above the water inlet area (8), the main area (9) and the water outlet area (10). The emergent plants (11) are one or more of reed, cattail, calamus, canna and lily of the valley.

8. The artificial wetland system for wastewater denitrification and phosphorus removal according to claim 4, characterized in that: The primary sedimentation tank (1) is elevated by a support, and an opening is provided at the bottom of the primary sedimentation tank (1) to form a sewage outlet (13), and the sewage outlet (13) is connected to a control valve via a pipeline.

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