Wetland purification system for tail water outlet of water purification plant into lake

Abstract

The application provides a wetland purification system for a tail water outlet into a lake of a water quality purification plant, a dam is arranged at the tail water outlet into the lake and a distance away from the tail water outlet to form an artificial lake, the lake bank of the artificial lake can keep the original ditch entrance and rainwater entrance of the lake, and a water outlet is arranged on the dam to be communicated with the lake; an ecological purification zone and a wetland conservation zone are sequentially arranged from the lake bank to the lake center at the artificial lake, a pre-buffer zone is arranged between the tail water outlet and the ecological purification zone and between the ditch and the ecological purification zone, and the tail water outlet is located at a side of the artificial lake away from the dam. Through the construction of the artificial lake and the wetland purification system, the content of pollutants in the tail water discharged into the lake can be effectively reduced, and the water quality of the lake can reach the V-class standard. Specifically, the water quality parameters after purification are as follows: the COD is less than 40 mg / L, the ammonia nitrogen is less than 2 mg / L, and the total phosphorus is less than 0.2 mg / L.

Description

Technical Field

[0001] The present invention relates to the field of wetland purification systems, in particular to a wetland purification system for the outlet of tail water into a lake at a water purification plant. Background Art

[0002] Constructed wetlands are artificially constructed, controlled, and operated structures or facilities similar to natural swamps. Their basic principle for sewage treatment is to evenly distribute sewage onto the artificial wetlands. As the sewage flows in a certain direction, it is purified through the synergistic physical, chemical, and biological effects of soil, artificial media, plants, and microorganisms. The establishment of constructed wetlands not only purifies lake water but also enhances the lake's landscape. Existing constructed wetlands include ex situ constructed wetland systems built on shore and in situ constructed wetland systems built directly in rivers and lakes. In situ constructed wetland systems have the advantages of conserving land resources and being relatively simple to construct.

[0003] Water purification plants are set up to treat domestic sewage and rainwater, and their tailwater may be discharged into lakes. The water quality at the tailwater outlet is poor. For example, the tailwater from a water purification plant has a COD of 80mg / L, ammonia nitrogen of 8mg / L, and total phosphorus of 0.5mg / L, which is worse than the water quality of lakes. If it is discharged directly into lakes, the water quality of the lakes will deteriorate and fail to meet the requirements of Class V water. Summary of the Invention

[0004] The main purpose of the present invention is to provide a wetland purification system for the tail water outlet of a water purification plant into a lake, so as to solve the problem that the water quality of the tail water outlet is poor, which will cause the water quality of the lake to deteriorate and the water quality of the lake to fail to meet the requirements of Class V water.

[0005] To solve the above technical problems, the technical solution adopted by the present invention is: a wetland purification system for the tailwater outlet of a water purification plant into a lake, wherein a dam is set at a certain distance away from the tailwater outlet of the lake to form an artificial lake, the lakeshore of the artificial lake can retain the original ditch inlet and rainwater inlet of the lake, and an outlet is set on the dam to communicate with the lake;

[0006] At the artificial lake, ecological purification areas and wetland conservation areas are set up in sequence from the lakeshore to the center of the lake. A front buffer zone is set up between the tailwater outlet and the ecological purification area. The tailwater outlet is located on the side of the artificial lake away from the dam.

[0007] In the preferred solution, the depth of the front buffer zone is 1.8-4.0m, emergent plants are planted in the 0-0.3m area of ​​the shore zone, floating leaf plants are planted in the 0.3-0.6m area, artificial aquatic plants are arranged in the 0.6-1.5m area, and a submersible aeration pump is installed in the front buffer zone.

[0008] In the preferred solution, the slope ratio of the front buffer zone is 1:5-1:10.

[0009] In the preferred embodiment, the tailwater outlet is the tailwater outlet of a water purification plant, which is the tailwater outlet of a water purification plant for primary rainwater.

[0010] In the preferred scheme, the ecological purification area is a surface wetland area, consisting of alternating shallows and deep pools, with an average water depth of 0.8-1.3m.

[0011] Among them, the top height of the shallow area is 0.2-0.4m below the normal water level.

[0012] In the preferred solution, emergent plants are planted in the shallow areas and submerged plants are planted in the deep pool areas;

[0013] Wave machines are installed in the dead water areas and some water flow channels of the ecological purification area.

[0014] In the preferred embodiment, the ecological purification area and the wetland conservation area are separated by a shoreline and connected by a plurality of outlets surrounding the wetland conservation area.

[0015] In the preferred scheme, the average water depth in the wetland conservation area is 1.5-2.5m, submerged plants are planted on the lake bottom, and emergent plants are planted along the coastal zone;

[0016] Among them, the wetland conservation area is connected to the lake through the outlet, where fish and benthic animals are cultured.

[0017] In the preferred solution, the depth of the front buffer zone at the tailwater outlet is 1.8-2.5m, the layout area of ​​artificial water plants is 25-35%, and the air supply capacity of the submersible aeration pump is 4-5m 3 / min;

[0018] The depth of the front buffer zone (5) at the ditch (3) is 3.0-4.0m, the layout area of ​​artificial water plants is 5-12%, and the air supply capacity of the submersible aeration pump is 5m 3 / min.

[0019] In the preferred embodiment, the artificial aquatic plants are carbon fiber aquatic plants, polyethylene aquatic plants, and natural fiber aquatic plants;

[0020] Emergent water plants include lotus, cattail, reed, and calamus;

[0021] Submerged plants include water hyacinth, water onion, bitter grass, and duckweed.

[0022] This invention provides a wetland purification system for the outlet of tailwater from a water purification plant into a lake. By constructing an artificial lake and wetland purification system, the system effectively reduces pollutant levels in tailwater discharged into the lake, bringing the lake's water quality up to Class V standards. Specifically, the purified water achieves COD less than 40 mg / L, ammonia nitrogen less than 2 mg / L, and total phosphorus less than 0.2 mg / L.

[0023] Ecological balance: The system sets up ecological purification areas and wetland conservation areas, and uses the synergistic effects of physics, chemistry and biology to purify sewage, which helps to restore and stabilize the lake ecosystem structure.

[0024] Landscape effect: The ecological purification area constructed at the outlet, by creating shallow terrain and deep pool areas, and matching emergent plants and submerged plants, not only plays a purifying role, but also increases the landscape effect of the lake.

[0025] Saving land resources: The establishment of an in-situ artificial wetland system has the advantage of saving land resources, is relatively simple to construct, and reduces interference with the surrounding environment.

[0026] Rainwater treatment: During rainfall, the system can intercept rainwater, prevent the lake water level from rising sharply, and reduce water pollution caused by rainfall.

[0027] Biodiversity: By planting submerged and emergent plants in wetland conservation areas, and farming fish and benthic animals, biodiversity has been increased and the recovery of aquatic ecosystems has been promoted.

[0028] Pollutant removal efficiency: Using artificial aquatic plants instead of submerged plants can avoid the problem of low survival rate of submerged plants under high pollution loads, while enhancing the purification effect of microorganisms on water quality and improving the pollutant removal efficiency of the front buffer zone.

[0029] Emergency handling capability: The installed surge machine can increase oxygen and aeration in emergency situations to avoid black and smelly water and ensure water quality.

[0030] Optimize flow field: The use of surge machines can also activate water, optimize the flow field in dead water areas, and improve the purification efficiency of the entire purification system.

[0031] Reducing pollution load: Through internal and external measures, such as reducing pollution load from domestic point sources, collecting industrial wastewater, and reducing rainwater runoff pollution, the pollution load has been effectively reduced and the water environment capacity has been improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The present invention will be further described below with reference to the accompanying drawings and examples:

[0033] Figure 1 It is a schematic diagram of the structural layout of the wetland purification system of the present invention;

[0034] Figure 2 It is a flow diagram of water flow in the wetland purification system of the present invention;

[0035] Figure 3 This is a digital-analysis diagram using the MIKE21 ECOLAB software of the present invention.

[0036] In the figure: dam 1; outlet 2; ditch 3; tailwater outlet 4; pre-buffer zone 5; ecological purification zone 6; wetland conservation zone 7; shallows area 8; deep pool area 9; wave machine 10; shore zone 11; outlet 12. DETAILED DESCRIPTION

[0037] Example 1

[0038] like Figures 1-2 As shown, a wetland purification system for the tailwater discharge outlet of a water purification plant into a lake is provided. A dam 1 is set at a certain distance away from the tailwater discharge outlet of the lake to form an artificial lake. The shore of the artificial lake can retain the original ditch inlet and rainwater inlet of the lake. An outlet 2 is provided on the dam 1 to communicate with the lake.

[0039] At the artificial lake, an ecological purification area 6 and a wetland conservation area 7 are set up in sequence from the lakeshore to the lake center, and a front buffer zone 5 is set between the tailwater outlet 4 and the ecological purification area 6. The tailwater outlet 4 is located on the side of the artificial lake away from the dam 1.

[0040] The functions of the front buffer zone 5 are to buffer water flow, distribute water and perform sedimentation.

[0041] The function of Ecological Purification Zone 6 is to mainly adopt ecological measures to purify the tailwater of water purification plants, water from ports and canals, and rainwater from shore outflows, etc., and to reduce the contents of COD, ammonia nitrogen, and total phosphorus in the water.

[0042] The functions of Wetland Conservation Area 7 are to stabilize water quality, restore ecosystem structure, and build a clear water grass ecosystem.

[0043] In the preferred solution, the pre-buffer zone 5 has a depth of 1.8-4.0m. Emergent plants are planted in the 0-0.3m area of ​​the shoreline, floating-leaf plants are planted in the 0.3-0.6m area, and artificial aquatic plants are arranged in the 0.6-1.5m area. A submersible aeration pump is installed in the pre-buffer zone 5. The artificial aquatic plants and submersible aeration pump in the pre-buffer zone 5 can reduce pollutants and minimize the impact of high pollution loads on the downstream ecosystem.

[0044] In a preferred embodiment, the slope ratio of the front buffer zone 5 is 1:5-1:10.

[0045] In the preferred embodiment, the tail water outlet 4 is the tail water outlet of a water purification plant, which is the tail water outlet of a water purification plant for primary rainwater.

[0046] In the preferred embodiment, the ecological purification area 6 is a surface wetland area, which is composed of shallow areas 8 with staggered shallow landforms and deep pool areas 9 with deep pools, with an average water depth of 0.8-1.3m; among which, the top height of the shallow area 8 is 0.2-0.4m below the normal water level.

[0047] In the preferred solution, emergent plants are planted in the shallows 8 and submerged plants are planted in the deep pools 9; and wave machines 10 are installed in the dead water area and some water flow channels of the ecological purification area 6. The functions of the wave machines 10 are: (1) to reduce the pollutants discharged and reduce the impact of high pollution loads on the construction of the back-end ecosystem. (2) to move water, optimize the flow field in the dead water area, and improve the purification efficiency. (3) to increase oxygen and aeration in emergency situations to avoid black and smelly water bodies. The distribution of the wave machines 10 is shown in the figure below:

[0048] In the preferred embodiment, the ecological purification area 6 and the wetland conservation area 7 are separated by a shoreline 11 and are connected by a plurality of outlets 12 surrounding the wetland conservation area 7 .

[0049] In the preferred solution, the average water depth in the wetland conservation zone 7 is 1.5-2.5 m, submerged plants are planted on the lake bottom, and emergent plants are planted along the coastal zone 11;

[0050] The wetland conservation area 7 is connected to the lake through the outlet 2, where fish and benthic animals are cultured.

[0051] In the preferred embodiment, the depth of the front buffer zone 5 at the tailwater outlet 4 is 1.8-2.5m, the layout area of ​​artificial water plants is 25-35%, and the air supply of the submersible aeration pump is 4-5m 3 / min;

[0052] The depth of the front buffer zone 5 at the ditch 3 is 3.0-4.0m, the layout area of ​​artificial aquatic plants is 5-12%, and the air supply capacity of the submersible aeration pump is 5m 3 / min.

[0053] In the preferred embodiment, the artificial aquatic plants are carbon fiber aquatic plants, polyethylene aquatic plants, and natural fiber aquatic plants;

[0054] Emergent water plants include lotus, cattail, reed, and calamus;

[0055] Submerged plants include water hyacinth, water onion, bitter grass, and duckweed.

[0056] Example 2

[0057] Further illustrate with reference to Example 1, Figure 1-3 In the structure shown, the depth of the front buffer zone 5 at the tailwater outlet 4 is 1.8-2.5m, the effective area is greater than 5000 square meters, the layout area of ​​artificial water plants is 25-35%, and the air supply capacity of the submersible aeration pump is 5m 3 / min. The depth of the front buffer zone 5 at the ditch 3 is 3.0-4.0m, the effective area is less than 3500 square meters, the layout area of ​​artificial water plants is 5-12%, and the air supply capacity of the submersible aeration pump is 5m 3 There are two ditch 3s, and accordingly, there are two pre-buffer zones 5 at ditch 3. This patent defines them as pre-buffer zone of ditch No. 1 and pre-buffer zone at the entrance of ditch No. 2. The total area of ​​the three pre-buffer zones is 11,500 m 2 Using artificial aquatic plants instead of submerged plants can avoid the problem of low survival rate of submerged plants under high pollution load, while enhancing the purification effect of microorganisms on water quality and improving the pollutant removal efficiency of the pre-buffer zone. Specifically, the artificial aquatic plants are carbon fiber grass with a length of 1m; the layout area of ​​the artificial aquatic plants in the pre-buffer zone 5 is: Tailwater pre-buffer zone: 2100m 2 , No. 1 ditch front buffer zone: 200m 2 , No. 2 ditch front buffer zone: 200m 2 .

[0058] Among them, the area of ​​ecological purification zone 6 is about 603,700 m 2 The average water depth is 1.0m. Emergent plants in the shallows are combined with submerged plants in the deep pools to create a near-natural surface flow artificial wetland. The area of ​​emergent plants is 39081.00m 2 The area of ​​floating leaf plants is 2732.00m 2 , the area of ​​submerged plants is 115000.00m 2 Among them, the wetland conservation area is about 446,500 m 2 The average water depth is 2.0m. Within the wetland conservation area, existing underwater topography is utilized to create a near-natural lake-like wetland. Submerged plants are planted at the lake bottom. Emergent plants are arranged in strips along the shore, with floating-leaf plants interspersed throughout. Aquatic animals such as fish and benthic animals are also introduced to restore a complete aquatic ecosystem. The distance between tailwater outlet 4 and wetland conservation area 7 is greater than the distance between ditch 3 and wetland conservation area 7. Wetland conservation area 7 utilizes the original artificial lake bottom for reconstruction.

[0059] The effective area of ​​ecological purification zone 6 is 1.1-1.5 times the effective area of ​​wetland conservation zone 7. The flow and water quality conditions of the artificial lake are shown in Table 1 and Table 2.

[0060] Table 1 Water treatment capacity and effect during the rainy period

[0061]

[0062] Table 2 Water treatment capacity and effect during non-rainfall period

[0063]

[0064] Among them, Table 1 shows the parameters during the rainy period, and Table 2 shows the parameters during the non-rainy period.

[0065] The area of ​​each district is shown in Table 3 and Table 4:

[0066] Table 3 Effective area and water depth of each zone

[0067] area Area m 2 ]] Water depth m Tailwater pre-buffer zone 6500 2 No. 1 ditch front buffer zone 3000 3.5 No. 2 ditch front buffer zone 2000 3.5 Ecological purification area 603700 1.2 Wetland conservation area 446512 2

[0068] Table 4 Parameters and residence time of each buffer zone

[0069]

[0070] Among them, in this patent, there are two ditch inlets and one tailwater inlet at the artificial lake, which are named Ditch Inlet No. 1, Ditch Inlet No. 1 and Tailwater Inlet respectively.

[0071] The quality of the treated water is shown in Table 5:

[0072] Table 5 Pollutant treatment effects in the most unfavorable case (winter) during the non-rainfall period (1 day after rainfall)

[0073]

[0074] Example 3

[0075] Further illustrate with reference to Examples 1-2, Figure 1-3 The structure shown in FIG1 shows, (1) the water quality parameters discharged into the lake are: COD less than 40 mg / L, ammonia nitrogen less than 2 mg / L, and total phosphorus less than 0.2 mg / L, which stabilizes the water quality of the lake area and makes the water quality of the lake reach Class V standards.

[0076] Table 6 Water quality indicators before and after treatment

[0077] COD (mg / l) Ammonia nitrogen (mg / l) Total phosphorus (mg / l) Tail water before treatment 80 8 0.5 Discharge into lakes ＜40 ＜2 ＜0.2 Category V standards ≤40 ≤2 ≤1

[0078] Under the most unfavorable conditions (winter) during the non-rainfall period (one day after rainfall), the water quality entering the lake is as follows:

[0079] Table 7 Water quality entering the lake during the non-rainfall period in winter

[0080] COD (mg / l) Ammonia nitrogen (mg / l) Total phosphorus (mg / l) Discharge into lakes 10 0.95 0.12

[0081] From Table 7, we can see that the water quality entering the lake is much better than the standard of Class V water.

[0082] According to the numerical model analysis of MIKE21 ECOLAB software, the COD, ammonia nitrogen and total phosphorus are as follows Figure 3 As shown:

[0083] (2) Construct an ecological landscape at the outlet.

[0084] In the ecological purification area, shallow landforms are created, and submerged plants are added to the deep pool area to construct a near-natural surface flow artificial wetland. This can be transformed in situ with minimal impact on the ecology.

[0085] (3) During the rainfall period, rainwater can be intercepted to prevent the water level of the lake from rising sharply.

[0086] During the rainfall period, the retention time of tailwater was 9.6 h and that of ditch was 21.6 h.

[0087] The above embodiments are merely preferred technical solutions of the present invention and should not be construed as limiting the present invention. The scope of protection of the present invention shall be the technical solutions set forth in the claims, including equivalent alternatives to the technical features of the technical solutions set forth in the claims. In other words, equivalent alternatives and improvements within this scope are also within the scope of protection of the present invention.

Claims

1. A wetland purification system for the tail water of a water purification plant into a lake outlet, characterized by: A dam (1) is set at a certain distance away from the tailwater outlet of the lake to form an artificial lake. The lakeshore of the artificial lake can retain the original ditch inlet and rainwater inlet of the lake, and an outlet (2) is set on the dam (1) to connect with the lake; At the artificial lake, an ecological purification zone (6) and a wetland conservation zone (7) are sequentially arranged from the lakeshore to the center of the lake, and a front buffer zone (5) is arranged between the tailwater outlet (4) and the ecological purification zone (6). The tailwater outlet (4) is located on the side of the artificial lake away from the dam (1); The depth of the front buffer zone (5) is 1.8-4.0m, with emergent plants planted in the 0-0.3m area of ​​the shore, floating leaf plants planted in the 0.3-0.6m area, and artificial aquatic plants arranged in the 0.6-1.5m area. A submersible aeration pump is installed in the front buffer zone (5); The ecological purification area (6) is a surface wetland area, consisting of a shallow area (8) with alternating shallow shoals and a deep pool area (9) with an average water depth of 0.8-1.3m; Among them, the top height of the shallow area (8) is 0.2-0.4m below the normal water level; The ecological purification area (6) and the wetland conservation area (7) are separated by a shoreline (11) and are connected by a plurality of discharge outlets (12) surrounding the wetland conservation area (7).

2. A wetland purification system for the tailwater outlet of a water purification plant into a lake according to claim 1, characterized in that: The slope ratio of the front buffer zone (5) is 1:5-1:

10.

3. The wetland purification system for the tailwater outlet of a water purification plant into a lake according to claim 1, characterized in that: The tailwater outlet (4) is the tailwater outlet of the water purification plant and the tailwater outlet of the water purification plant for primary rainwater.

4. A wetland purification system for the tail water outlet of a water purification plant according to claim 1, characterized in that: Emergent plants are planted in the shallows (8), and submerged plants are planted in the deep pools (9); A wave generator (10) is provided in the dead water area and part of the water flow channel of the ecological purification area (6).

5. The wetland purification system for the tailwater outlet of a water purification plant into a lake according to claim 1, characterized in that: The average water depth in the wetland conservation area (7) is 1.5-2.5 m, with submerged plants planted on the lake bottom and emergent plants planted along the coastal zone (11); Among them, the wetland conservation area (7) is connected to the lake through the outlet (2), and fish and benthic animals are cultured therein.

6. The wetland purification system for the tailwater outlet of a water purification plant into a lake according to claim 1, characterized in that: The depth of the front buffer zone (5) at the tailwater outlet (4) is 1.8-2.5m, the layout area of ​​artificial water plants is 25-35%, and the air supply of the submersible aeration pump is 4-5m 3 / min; The depth of the front buffer zone (5) at the ditch (3) is 3.0-4.0m, the layout area of ​​artificial aquatic plants is 5-12%, and the air supply capacity of the submersible aeration pump is 5m 3 / min.

7. A wetland purification system for the tailwater outlet of a water purification plant into a lake according to any one of claims 1 to 6, characterized in that: Artificial aquatic plants include carbon fiber grass, polyethylene aquatic plants, and natural fiber aquatic plants; Emergent water plants include lotus, cattail, reed, and calamus; Submerged plants include water hyacinth, water onion, bitter grass, and duckweed.

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