Wetland purification system for tail water inlet lake discharge port of water quality purification plant

Abstract

The invention provides a wetland purification system for a tail water lake-entering discharge port of a water quality purification plant, a dam is arranged at the tail water lake-entering discharge port of a lake and away from the tail water discharge port by a certain distance to form an artificial lake, the lake bank of the artificial lake can reserve an original ditch inlet and a rainwater inlet of the lake, and a water outlet is formed in the dam to be communicated with the lake; at the artificial lake, an ecological purification area and a wetland conservation area are sequentially arranged from the lake bank to the lake center, front buffer areas are arranged between the tail water discharge port and the ecological purification area and between the ditch and the ecological purification area, and the tail water discharge port is located on the side, away from the dam, of the artificial lake. By constructing the artificial lake and the wetland purification system, the content of pollutants in tail water discharged into the lake can be effectively reduced, so that the water quality of the lake reaches the V-type standard. Specifically, the purified water quality parameters are as follows: COD is less than 40mg / L, ammonia nitrogen is less than 2mg / L, and total phosphorus is less than 0.2 mg / L.

Description

Technical Field

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

[0002] In recent years, a large amount of solid waste and polluted water have flowed into lakes due to improper treatment, resulting in deterioration of lake water quality and decline in the self-purification capacity of water bodies, which has seriously affected the urban landscape and the ecosystem around the lakes. Especially during rainfall, due to the lack of pre-rainwater treatment facilities at the entrance of the lake, various polluted water bodies, solid waste, etc. flow into the lake with rainwater, causing a large accumulation of nitrogen, phosphorus, organic matter and various nutrients in the lake water, and the lake ecosystem is unbalanced or even collapsed. Artificial wetlands are artificially constructed and controlled structures or facilities similar to natural wetlands in swamps. The basic principle of sewage treatment is to evenly distribute sewage to artificially constructed wetlands. In the process of sewage flowing in a certain direction, it mainly uses the physical, chemical and biological synergistic effects of soil, artificial media, plants and microorganisms to purify sewage. A technology. The establishment of artificial wetlands can not only purify lake water bodies, but also increase the landscape effect of lakes. Existing artificial wetlands include ex situ artificial wetland systems built on the shore and in situ artificial wetland systems built directly in rivers and lakes. The in situ artificial wetland system has the advantages of saving land resources and simple construction.

[0003] In order to treat domestic sewage or rainwater, water purification plants are set up, and the tail water of the water purification plants may be discharged into lakes. The water quality of the tail water outlet is poor. For example, the tail water of the 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 the lake. If it is directly discharged into the lake, the water quality of the lake will deteriorate and the water quality of the lake will not 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 deteriorate the water quality of the lake and make the water quality of the lake fail to meet the requirements of Class V water.

[0005] In order to solve the above technical problems, the technical solution adopted by the present invention is: a wetland purification system for the tailwater discharge outlet of a water purification plant, a dam is set at the tailwater discharge outlet of the lake and a certain distance away from the tailwater discharge outlet to form an artificial lake, the lakeshore of the artificial lake can retain the original ditch entrance 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 embodiment, 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 shallow shoal areas and deep pool areas, 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 dead water areas and some water flow channels in the ecological purification area.

[0014] In the preferred embodiment, the ecological purification area is separated from the wetland conservation area by a shore zone 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 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 waterweed is 5-12%, and the air supply of the submersible aeration pump is 5m 3 / min.

[0019] In the preferred embodiment, the artificial water grass is carbon fiber grass, polyethylene water grass, or natural fiber water grass;

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

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

[0022] The present invention provides a wetland purification system for the outlet of tail water from a water purification plant into a lake, and the water quality is improved: by constructing an artificial lake and a wetland purification system, the pollutant content in the tail water discharged into the lake can be effectively reduced, so that the water quality of the lake reaches Class V standards. Specifically, the water quality parameters after purification are: COD less than 40mg / L, ammonia nitrogen less than 2mg / L, and total phosphorus less than 0.2mg / L.

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

[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] Stormwater 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, as well as farming fish and benthic animals, biodiversity is increased and the recovery of aquatic ecosystems is promoted.

[0028] Pollutant removal efficiency: Artificial aquatic plants are used instead of submerged plants to 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 wave 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 move water, optimize the flow field in dead water areas, and improve the purification efficiency of the entire purification system.

[0031] Reduction of pollution load: Through internal and external measures, such as reduction of pollution load from domestic point sources, full collection of industrial wastewater, and reduction of 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 in conjunction with the accompanying drawings and embodiments:

[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; front buffer zone 5; ecological purification zone 6; wetland conservation zone 7; shallow beach 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 is provided. A dam 1 is provided at a certain distance away from the tailwater discharge 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. 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 arranged in sequence from the lakeshore to the center of the lake, a front buffer zone 5 is arranged between the tailwater outlet 4 and the ecological purification area 6, and 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: buffering water flow, water distribution and sedimentation.

[0041] The function of the ecological purification area 6 is to mainly use ecological measures to purify the tail water of the water purification plant, the water from the port channel, the rainwater from the shore outfall, etc., and reduce the content of COD, ammonia nitrogen, total phosphorus, etc. in the water flow.

[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 depth of the front buffer zone 5 is 1.8-4.0m, the 0-0.3m area of ​​the shore zone is planted with emergent plants, the 0.3-0.6m area is planted with floating leaf plants, the 0.6-1.5m area is arranged with artificial aquatic plants, and a submersible aeration pump is set in the front buffer zone 5. In the front buffer zone 5, the setting of artificial aquatic plants and submersible aeration pumps can reduce pollutants and reduce the impact of high pollution loads on the construction of the back-end ecosystem.

[0044] In the 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 beach terrain and deep pool areas 9 with deep pools, with an average water depth of 0.8-1.3m; wherein 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 shallow area 8, and submerged plants are planted in the deep pool area 9; 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 at the discharge port and reduce the impact of high pollution load 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. 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 shore zone 11 and are connected by a plurality of discharge outlets 12 surrounding the wetland conservation area 7 .

[0049] In the preferred solution, the average water depth of the wetland conservation area 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, and fish and benthic animals are cultured therein.

[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 water plants is 5-12%, and the air supply of the submersible aeration pump is 5m 3 / min.

[0053] In the preferred embodiment, the artificial water grass is carbon fiber grass, polyethylene water grass, or natural fiber water grass;

[0054] Emergent plants are 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 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 of the submersible aeration pump is 5m 3 / min. There are two ditches 3, and accordingly, there are two front buffers 5 at the ditches 3, which are defined in this patent as the front buffer of ditch No. 1 and the front buffer of the entrance of ditch No. 2. The total area of ​​the three front buffers is 11,500 m 2 Using artificial water grass to replace submerged plants avoids 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 front buffer zone. Specifically, the artificial water grass is carbon fiber grass with a length of 1m; the layout area of ​​artificial water grass in the front buffer zone 5 is: Tailwater front 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 construct 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 , with an average water depth of 2.0m. In the wetland conservation area, the existing underwater terrain is used to construct a near-natural lake wetland. Submerged plants are arranged at the bottom of the lake, emergent plants are arranged in strips along the coast, and floating leaf plants are planted for embellishment. At the same time, aquatic animals such as fish and benthic animals are added to restore a complete aquatic ecosystem. Among them, the distance between the tailwater outlet 4 and the corresponding position of the wetland conservation area 7 is farther than the distance between the ditch 3 and the corresponding position of the wetland conservation area 7. The wetland conservation area 7 uses the lake bottom of the original artificial lake for transformation.

[0059] The effective area of ​​ecological purification area 6 is 1.1-1.5 times the effective area of ​​wetland conservation area 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 <![CDATA[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 water quality after treatment is shown in Table 5:

[0072] Table 5 Pollutant treatment effect 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, (1) the water quality parameters discharged into the lake are: COD less than 40mg / L, ammonia nitrogen less than 2mg / L, total phosphorus less than 0.2mg / L, stabilizing the water quality of the lake area and making 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 Standard ≤40 ≤2 ≤1

[0078] Under the most unfavorable conditions (winter) during the non-rainfall period (1 day after rainfall), the water quality entering the lake is as follows:

[0079] Table 7 Water quality entering the lake during the non-rainy 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, it can be seen that the water quality entering the lake is far better than the standard of Class V water.

[0082] According to the numerical model analysis of MIKE21 ECOLAB software, the conditions of 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, a shallow beach terrain is created, and submerged plants are matched in the deep pool area to construct a near-natural surface flow artificial wetland. It can be transformed in situ with little 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 is 9.6 h and that of ditch is 21.6 h.

[0087] The above embodiments are only preferred technical solutions of the present invention and should not be regarded as limiting the present invention. The protection scope of the present invention shall be the technical solutions recorded in the claims, including equivalent replacement solutions of the technical features in the technical solutions recorded in the claims. That is, equivalent replacement improvements within this scope are also within the protection scope of the present invention.

Claims

1. A wetland purification system for the tail water of a water purification plant into a lake, 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 communicate with the lake; At the artificial lake, an ecological purification area (6) and a wetland conservation area (7) are arranged in sequence from the lake shore to the lake center, a front buffer zone (5) is arranged between the tailwater outlet (4) and the ecological purification area (6), and the tailwater outlet (4) is located on the side of the artificial lake far from the dam (1).

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

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

10.

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

5. A wetland purification system for the tailwater discharge outlet of a water purification plant into a lake according to claim 1, characterized in that: The ecological purification area (6) is a surface wetland area, consisting of a shallow area (8) with alternating shallow shoal terrain and a deep pool area (9) with an average water depth of 0.8-1.3m; The top height of the shallow area (8) is 0.2-0.4 m below the normal water level.

6. A wetland purification system for the tail water outlet of a water purification plant according to claim 5, characterized in that: Emergent plants are planted in the shallow areas (8), and submerged plants are planted in the deep pool areas (9); A wave machine (10) is arranged in the dead water area and part of the water flow channel of the ecological purification area (6).

7. A wetland purification system for the tailwater discharge outlet of a water purification plant into a lake according to claim 5, characterized in that: The ecological purification area (6) and the wetland conservation area (7) are separated by a shore zone (11) and are connected by a plurality of discharge outlets (12) surrounding the wetland conservation area (7).

8. A wetland purification system for the tailwater discharge outlet of a water purification plant into a lake according to claim 7, 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); The wetland conservation area (7) is connected to the lake through the outlet (2), and fish and benthic animals are cultured therein.

9. A wetland purification system for the tailwater discharge 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 waterweed is 5-12%, and the air supply of the submersible aeration pump is 5m 3 / min.

10. A wetland purification system for the tail water outlet of a water purification plant according to any one of claims 1 to 9, characterized in that: Artificial water grass includes carbon fiber grass, polyethylene water grass, and natural fiber water grass; Emergent plants are lotus, cattail, reed, and calamus; Submerged plants include water hyacinth, water onion, bitter grass, and duckweed.

Images