Ecological filter dam for nitrogen and phosphorus removal and water purification method based on the filter dam

Abstract

A denitrification and phosphorus removal ecological filter dam includes a plurality of boxes, which are symmetrically arranged along the central axis of the river channel and are arranged across the flow channel. The plurality of boxes together form two dam bodies. An inlet end is arranged on the upstream side of the dam body close to the river bank, and an outlet end is arranged on the downstream side of the dam body close to the center of the river channel. A gabion is provided on the inlet end and the outlet end respectively, and a stacked beam gate is provided on the gabion. The stacked beam gate on the inlet end is arranged close to the upstream inlet chute, and the stacked beam gate on the outlet end is arranged close to the downstream. Water holes are provided on the side walls of the boxes to form a plurality of water holes on the side walls of a single dam body, and adjacent water holes are arranged in an up-and-down staggered manner in the vertical direction to form a vertical flow-bend type water purification channel. The patent of the present invention adopts the above structure, which can effectively reduce the concentration of various pollutants in similar water bodies, and is convenient to build, occupies a relatively small area, and can adapt to various water level conditions in the river channel. After long-term operation, the siltation problem can be solved by simple management and maintenance.

Description

Technical Field

[0001] The invention relates to the technical field of ecological and environmentally friendly sewage treatment, and specifically to an ecological filter dam for denitrification and phosphorus removal and a water purification method based on the filter dam. Background Art

[0002] The demand for governance and construction is getting higher and higher, but the contradiction between urbanization and environmental impact is becoming more prominent. A large amount of domestic sewage and non-point source pollution are discharged into water bodies, causing water quality to deteriorate. Therefore, it is urgent to solve the water environment problems of urban rivers and wetlands, and it is crucial to carry out research on relevant new technologies to ensure the ecological health of such water bodies.

[0003] In-situ purification technology is an important technology for treating this type of water body. Ecological filter dam is one of them. It uses fillers as carriers to form biofilms to perform biological-ecological purification on sewage.

[0004] The Chinese invention patent application with application number 201910681165.0 discloses a vertical flow-bend compound enhanced denitrification and phosphorus removal and anti-blocking ecological filter dam for urban non-flood-prone rivers. The filter dam has enhanced denitrification and phosphorus removal effects, and also achieves certain anti-blocking and landscape effects. However, due to the limitations of the structural layout, this type of dam occupies a large proportion of the river channel. Therefore, it is only an ecological filter dam for urban non-flood-prone rivers. At the same time, the backwash system and construction of the filter dam are relatively complex, which is not conducive to simple management and maintenance.

[0005] The Chinese invention patent application with application number 202110844732.9 discloses an ecological island-type water purification filter dam for filtering and purifying urban river water. This filter dam also has the problem of occupying a large amount of river channels and has poor applicability. Summary of the invention

[0006] The technical problem to be solved by the present invention is to provide an ecological filter dam for nitrogen and phosphorus removal and a water purification method based on the filter dam. The ecological filter dam can effectively reduce the concentration of various pollutants in similar water bodies. At the same time, it is easy to construct, occupies a relatively small area, and can adapt to various water level conditions in the river. After long-term operation, the siltation problem can be solved through simple maintenance.

[0007] In order to solve the above technical problems, the technical solution adopted by the present invention is: a denitrification and phosphorus removal ecological filter dam, comprising a box body, wherein the box body is multiple, and the multiple boxes are symmetrically arranged along the central axis of the river channel and across the flow channel, and the multiple boxes together form two dam bodies, and an inlet end is arranged on the end of the upstream surface of the dam body close to the river bank, and a water outlet end is arranged on the end of the downstream surface of the dam body close to the center of the river channel;

[0008] A gabion is provided on the water inlet and the water outlet respectively, and a stopcock is provided on the gabion. The stopcock on the water inlet is arranged close to the upstream water inlet chute, and the stopcock on the water outlet is arranged close to the downstream.

[0009] The box side walls are provided with water holes to form a plurality of water holes on the box side walls of a single dam body, and adjacent water holes are arranged vertically in an up-and-down staggered manner to form a vertical flow-bend type water purification channel.

[0010] In a preferred solution, the gabion is filled with crushed stones and a cover plate is arranged on the top of the gabion.

[0011] In a preferred solution, in the plurality of boxes, water holes connected to the upstream water inlet and the downstream water outlet are further provided with water splash walls.

[0012] In a preferred solution, the box is filled with denitrification and dephosphorization fillers, an impermeable membrane is laid on the top of the denitrification and dephosphorization fillers, and planting soil is laid on top of the impermeable membrane and green plants are planted.

[0013] In a preferred solution, a ventilation barrier is provided between the planting soils in adjacent boxes, the ventilation barrier is filled with gravel, and an exhaust cap is installed in the gravel.

[0014] In a preferred solution, the water holes on the water-passing flower wall are arranged at an angle of 60° to the water inlet direction.

[0015] In a preferred solution, the height of the gabion is lower than the height of the box body, the cover plate on the top of the gabion is flush with the top surface of the box body, and the cover plate and the gabion form a maintenance well structure for manual dredging.

[0016] The water purification method based on the above-mentioned denitrification and phosphorus removal ecological filter dam comprises the following steps:

[0017] 1) Control the stopcock gates at the inlet and outlet ends of the dam body according to the upstream water level, so that the upstream water overflows into the dam body;

[0018] 2) The upstream water flows through the gabion and passes through the gravel inside the gabion to achieve preliminary filtration of solid impurities;

[0019] 3) The water flows into the box and gradually passes through the denitrification and phosphorus removal fillers in multiple boxes along the vertical flow-baffled water purification channel;

[0020] 4) The water after denitrification and phosphorus removal overflows to the downstream through the stoplog gate on the box in the middle of the dam body.

[0021] In the preferred solution, by controlling the water retaining height of the stop gate at the water inlet end to rise and the water retaining height of the stop gate at the water outlet end to fall, the flow rate of the water flowing through the box body is accelerated to achieve the purpose of flushing the box body.

[0022] In the preferred solution, during flood discharge, the box in the middle of the flow channel is dismantled to achieve normal flood discharge operation of the flow channel, and after the flood season is over, the box in the middle is reinstalled to continue water purification operations.

[0023] The present invention provides a denitrification and phosphorus removal ecological filter dam and a water purification method based on the filter dam, which has the following beneficial effects by adopting the above structure and method:

[0024] (1) By horizontally arranging the water inlet section, dam body section and water outlet section to form an ecological filter dam, the nitrogen and phosphorus removal effect of the ecological filter dam can be effectively enhanced, and the water purification retention time can be extended. The ingenious structural design reduces the area of ​​the river occupied by the dam body and reduces the impact on the flood discharge of the river;

[0025] (2) The upstream and downstream water level difference is controlled by the stoplog gates installed at the inlet and outlet sections, which increases the flow rate of the dam body and prevents siltation. The inspection wells under the cover can also be regularly desilted, making maintenance easier.

[0026] (3) Green plants can be planted on the upper part of the box to create a good landscape effect and improve the river habitat. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The present invention will be further described below in conjunction with the accompanying drawings and embodiments:

[0028] Figure 1 It is a cross-sectional view of the present invention;

[0029] Figure 2 A top view of the present invention;

[0030] Figure 3 It is the AA cross-sectional view of the present invention;

[0031] Figure 4 It is the BB cross-sectional view of the present invention;

[0032] Figure 5 It is the CC cross-sectional view of the present invention;

[0033] Figure 6 It is the DD cross-sectional view of the present invention;

[0034] Figure 7 It is the EE cross-sectional view of the present invention;

[0035] Figure 8 It is the FF cross-sectional view of the present invention.

[0036] In the figure: upstream water inlet 1, stopcock 2, gabion 3, water-passing flower wall 4, denitrification and phosphorus removal filler 5, box 6, planting soil 7, exhaust cap 8, gravel 9, green plants 10, anti-seepage membrane 11, cover plate 12, water-passing hole 13, downstream water outlet 14, water inlet chute 15. DETAILED DESCRIPTION

[0037] Embodiment 1:

[0038] like Figure 1-8In the embodiment, a denitrification and phosphorus removal ecological filter dam comprises a box body 6, wherein the box body 6 is multiple, and the multiple boxes 6 are symmetrically arranged along the central axis of the river channel and are arranged across the flow channel, and the multiple boxes 6 together form two dam bodies, and a water inlet end is arranged on the end of the upstream surface of the dam body close to the river bank, and a water outlet end is arranged on the end of the downstream surface of the dam body close to the center of the river channel;

[0039] A gabion 3 is provided on the water inlet end and the water outlet end respectively, and a stopcock 2 is provided on the gabion 3. The stopcock 2 on the water inlet end is arranged close to the upstream water inlet chute 15, and the stopcock 2 on the water outlet end is arranged close to the downstream.

[0040] The side walls of the box body 6 are provided with water holes 13 to form a plurality of water holes 13 on the side walls of the box body 6 of a single dam body, and adjacent water holes 13 are arranged vertically in an alternating manner to form a vertical flow-bend type water purification channel.

[0041] In a preferred solution, the gabion 3 is filled with crushed stones, and a cover plate 12 is arranged on the top of the gabion 3.

[0042] In a preferred solution, in the plurality of boxes 6 , a water-passing hole 13 connected to the upstream water inlet 1 and the downstream water outlet 14 is further provided with a water-passing flower wall 4 .

[0043] In a preferred solution, the box body 6 is filled with a denitrification and dephosphorization filler 5 , an impermeable membrane 11 is laid on top of the denitrification and dephosphorization filler 5 , and planting soil 7 is laid on top of the impermeable membrane 11 and green plants 10 are planted.

[0044] In a preferred solution, a ventilation barrier is provided between the planting soils 7 in adjacent boxes 6 , the ventilation barrier is filled with gravel 9 , and an exhaust cap 8 is installed in the gravel 9 .

[0045] In a preferred solution, the water holes on the water-passing flower wall 4 are arranged at an angle of 60° to the water inlet direction.

[0046] In a preferred solution, the height of the gabion 3 is lower than that of the box body 6, the cover plate 12 on the top of the gabion 3 is flush with the top surface of the box body 6, and the cover plate 12 and the gabion 3 form a maintenance well structure for manual dredging.

[0047] Embodiment 2:

[0048] Based on Example 1:

[0049] The total length of the ecological filter dam is 25.2m, and the water inlet section and the water outlet section are arranged symmetrically, with the water inlet section arranged at both ends and the water outlet section arranged in the middle. Figure 1 Taking the example shown in the figure, the dam body is symmetrically divided into 6 small boxes, so that the treated water body as a whole enters from both ends and exits from the middle.

[0050] The net size of the water inlet section is 3.0×1.6×3.0m (length×width×height), the water level elevation of the upstream water inlet 1 is 30.7m, the slope of the water inlet chute 15 is 1:1, the elevation of the slope bottom is 28.2m, the gate slot height on both sides of the stacked beam gate 2 is 3.0m, and it is composed of multiple pieces of carbon steel materials with a size of 1.5×0.4m (width×height). The gate retaining height is controlled according to the upstream and downstream water level requirements; the stacked beam gate 2 and the cover plate 12 form an inspection well with dredging and maintenance functions. A gabion 3 with a size of 3.0×1.0×1.0m (length×width×height) is provided at the bottom of the well, and the inside of the gabion 3 is filled with limestone with a particle size of 30-50mm; the gabion 3 is close to the water-passing flower wall 4 at the bottom of the water inlet box 6 of the ecological filter dam, and the water-passing flower wall 4 has a size of 3.0×0.8m (length×height), and the water inlet hole of the flower wall is at an angle of 60° with the water inlet direction.

[0051] The net size of the dam section is 25.2×3.4×3.0m (length×width×height), which is divided into 6 boxes 6 with a size of 4.0×3.4×3.0m (length×width×height). The side wall of the box 6 is provided with water holes 13 with a size of 2.0×0.8m (length×height). The elevations of the water holes 13 of adjacent boxes 6 are staggered up and down. The box 6 is filled with denitrification and dephosphorization filler 5, which has high porosity, strong adsorption capacity, and a particle size of 1 The filler is composed of special expanded clay with a diameter of 0 to 12 mm and graded zeolite with a particle size of 16 to 32 mm, and the filler depth is 2.5 m; a 9 mm thick HDPE geomembrane is laid on the upper layer of the filler as an impermeable membrane 11, and planting soil 7 with a thickness of 0.5 m is laid on the impermeable membrane as a base for planting green plants 10; a ventilation interlayer is arranged in the middle of the planting soil 10, and the interlayer is composed of an exhaust cap 8 and gravel 9, and the exhaust cap 8 adopts a DN50 UPVC pipe.

[0052] The structural arrangement of the water outlet section is similar to that of the water inlet section. The water treated by the box body 6 flows through the gabion 3 set in the inspection well room through the water-passing flower wall 4 with a higher elevation. The size of the gabion 3 is 3.0×1.0×2.0m (length×width×height); then it overflows through the stoplog gate 2 and is finally discharged into the downstream water body 14 with a water level elevation of 30.1m.

[0053] Embodiment 3:

[0054] On the basis of Example 1, the water purification method based on the denitrification and phosphorus removal ecological filter dam described in Example 1 includes the following steps:

[0055] 1) According to the water level of the upstream inlet 1, the stopcock gates 2 at the inlet and outlet ends of the dam body are controlled to allow the upstream inlet 1 to overflow and enter the dam body;

[0056] 2) The upstream influent 1 flows through the gabion 3 and passes through the gravel inside the gabion 3 to achieve preliminary filtration of solid impurities;

[0057] 3) The water flows into the box 6 and gradually passes through the denitrification and dephosphorization fillers 5 in the multiple boxes 6 along the vertical flow-baffled water purification channel;

[0058] 4) The water after denitrification and phosphorus removal overflows to the downstream through the stoplog gate 2 on the box 2 in the middle of the dam body.

[0059] In the preferred scheme, by controlling the water retaining height of the lapped beam gate 2 at the water inlet end to rise and the water retaining height of the lapped beam gate 2 at the water outlet end to fall, the flow rate of the water flowing through the box body 6 can be accelerated to achieve the purpose of flushing the box body 6. In addition, the gabion 3 in the inspection well room can further filter and intercept debris, and the water-passing flower wall 4 can improve the stability of water inlet and the effect of uniform water distribution. After long-term operation, the debris in the well can be manually cleared.

[0060] In the preferred solution, the dam body section is formed by 6 (or other even numbers) of independent boxes connected horizontally, and water holes are provided on the side walls of the boxes. The water holes of adjacent boxes are staggered up and down to form a vertical flow-baffled water purification channel, which can change the flow direction of the water body to increase the hydraulic retention time, increase the contact time with expanded clay and zeolite, improve the adsorption effect and the formation of biofilm. At the same time, the setting of the upper and lower staggered and exhaust caps can form anaerobic, anoxic and aerobic purification environments in the boxes, which are easy to produce nitrification-denitrification reactions, and ultimately improve the effects of nitrogen removal and phosphorus removal.

[0061] The present invention has an ingenious structural design, small footprint, low cost, and simple maintenance. The removal rates of NH3-N and TP can reach 43% and 38% respectively. After long-term operation, the water level difference between the upstream and downstream can be controlled regularly by clearing the inspection well and using the stacked beam gate to increase the water flow rate for automatic flushing, so that the water flow capacity can be stabilized at more than 90% of the design capacity. The structure of multiple box bodies 6 spliced ​​together has the advantages of convenient disassembly and installation for the ecological filter dam set in the flood channel. During the flood season, the box body 6 in the middle of the flow channel can be disassembled to realize the normal flood discharge operation of the flow channel. After the flood season ends, the box body 6 in the middle can be reinstalled to continue the water purification operation.

Claims

1. A water purification method for denitrification and phosphorus removal ecological filter dam, characterized in that: It comprises a box body (6), wherein the box bodies (6) are multiple, and the multiple box bodies (6) are symmetrically arranged along the central axis of the river channel and straddle the flow channel, and the multiple box bodies (6) together form two dam bodies, and an inlet end is arranged on the end of the upstream surface of the dam body close to the river bank, and a water outlet end is arranged on the end of the downstream surface of the dam body close to the center of the river channel; A gabion (3) is provided on the water inlet end and the water outlet end respectively, and a stopcock (2) is provided on the gabion (3). The stopcock (2) on the water inlet end is arranged close to the upstream water inlet chute (15), and the stopcock (2) on the water outlet end is arranged close to the downstream. The side walls of the box body (6) are provided with water holes (13), and the water holes (13) on the side walls of the multiple box bodies (6) that form a single dam body are arranged, and the adjacent water holes (13) are arranged in an up-and-down staggered manner in the vertical direction to form a vertical flow-bend type water purification channel; A ventilation barrier is provided between the planting soil (7) in adjacent boxes (6), the ventilation barrier is filled with gravel (9), and an exhaust cap (8) is installed in the gravel (9); The water purification method of the denitrification and phosphorus removal ecological filter dam includes the following steps: 1) Controlling the stopcock gates (2) at the inlet and outlet ends of the dam body according to the water level of the upstream inlet (1) so that the upstream inlet (1) overflows and enters the dam body; 2) The upstream influent (1) flows through the gabion (3) and passes through the gravel inside the gabion (3) to achieve preliminary filtration of solid impurities; 3) The water flows into the box (6) and gradually passes through the denitrification and dephosphorization fillers (5) in the multiple boxes (6) along the vertical flow-baffled water purification channel; 4) The water after the denitrification and dephosphorization treatment overflows to the downstream through the stoplog gate (2) on the box (2) in the middle of the dam body; The box (6) is filled with a denitrification and dephosphorization filler (5), an impermeable membrane (11) is laid on the top of the denitrification and dephosphorization filler (5), and planting soil (7) is laid on top of the impermeable membrane (11) and green plants (10) are planted; The height of the gabion (3) is lower than that of the box body (6); the cover plate (12) on the top of the gabion (3) is flush with the top surface of the box body (6); the cover plate (12) and the gabion (3) form a maintenance well structure for manual silt removal.

2. The water purification method of a denitrification and phosphorus removal ecological filter dam according to claim 1, characterized in that: The gabion (3) is filled with crushed stones, and a cover plate (12) is arranged on the top of the gabion (3).

3. The water purification method of a denitrification and phosphorus removal ecological filter dam according to claim 1 is characterized in that: In the plurality of boxes (6), a water-passing hole (13) connected to the upstream water inlet (1) and the downstream water outlet (14) is also provided with a water-passing splash wall (4).

4. The water purification method of a denitrification and phosphorus removal ecological filter dam according to claim 1, characterized in that: The water holes on the water-passing flower wall (4) are arranged at an angle of 60° to the water inlet direction.

5. The water purification method of a denitrification and phosphorus removal ecological filter dam according to claim 1, characterized in that: By controlling the water retaining height of the stop gate (2) at the water inlet end to rise and the water retaining height of the stop gate (2) at the water outlet end to fall, the flow rate of the water flowing through the box body (6) is accelerated to achieve the purpose of flushing the box body (6).

6. The water purification method of a denitrification and phosphorus removal ecological filter dam according to claim 5, characterized in that: During flood discharge, the box body (6) in the middle of the flow channel is disassembled to achieve normal flood discharge operation of the flow channel, and after the flood season ends, the box body (6) in the middle is reinstalled to continue water purification operation.

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