Composite type circulating constructed wetland tail water treatment system and method thereof

Abstract

This invention discloses a composite circulating constructed wetland effluent treatment system and method, belonging to the technical field of water treatment systems. The invention includes a vertical subsurface flow wetland, a horizontal subsurface flow wetland, and a surface flow wetland, connected in series. The effluent first passes through the water distribution unit of the vertical subsurface flow wetland, flowing upwards through a first multi-layer packing material. The initially purified effluent then enters the perforated pipe water distribution unit of the horizontal subsurface flow wetland, flowing horizontally through a second multi-layer packing material. The further purified effluent is then discharged into a circulating plug flow surface flow wetland. This invention combines three wetland systems and enhances the circulating surface flow wetland, with reasonable functional zoning. The effluent first enters the vertical and horizontal subsurface flow wetlands, where the removal of various types of organic matter, nitrogen, phosphorus, and other pollutants is enhanced. Subsequently, it enters the surface flow wetland, where submerged plants at the bottom and emergent plants at the surface work together to enhance water quality purification and improve the effluent purification effect.

Description

Technical Field

[0001] This invention relates to the field of water treatment system technology, and more specifically, to a composite circulating constructed wetland effluent treatment system and method thereof. Background Technology

[0002] In constructed wetland systems, insoluble organic particles in wastewater are primarily removed through interception, filtration, and sedimentation by the substrate and plants. Dissolved organic matter, on the other hand, is mainly absorbed by microorganisms in the wetland and decomposed or utilized through anaerobic and aerobic metabolic processes. The purification effect of constructed wetlands on organic pollutants is related to factors such as system type, substrate type, reoxygenation conditions, retention time, and influent water quality. Constructed wetlands utilize aerobic microorganisms (including facultative microorganisms) to degrade organic matter through biological metabolism in the presence of oxygen, stabilizing and rendering it harmless. Microorganisms use organic pollutants in the water as substrates for aerobic metabolism, releasing energy step by step through a series of biochemical reactions, ultimately stabilizing as low-energy inorganic substances, achieving the requirement of harmlessness. The main nitrogen removal pathways in constructed wetland systems include: assimilation and absorption and storage by plants and microorganisms, adsorption by the substrate, deposition of organic nitrogen, and the generation and release of nitrogen gas through microbial nitrification and denitrification. Phosphorus removal in wetland systems primarily relies on the combined action of the substrate, plants, and microorganisms, achieving removal through a series of complex chemical, physical, and biological processes. Among these, polyphosphate-accumulating bacteria and other microorganisms mineralize and decompose organic phosphorus compounds and oxidize and reduce inorganic phosphorus compounds, altering their solubility through enzymatic reactions. Wetland plants, on the other hand, directly remove phosphorus-containing pollutants from wastewater through root absorption and accumulation, transforming them into their own plant matter. Simultaneously, plants indirectly promote phosphorus purification by influencing the microbial growth environment through oxygen transport via their roots and stems.

[0003] Plants in constructed wetlands can also transport oxygen to the water and increase its activity. Wetland plants also play an important role in controlling water pollution and degrading harmful substances.

[0004] Constructed wetland systems offer advantages such as large buffer capacity, high treatment efficiency, simple technology, low investment, and low operating costs, making them ideal for further purification of wastewater effluent from wastewater treatment plants. Based on wastewater flow patterns, constructed wetlands can be categorized into surface flow constructed wetlands, horizontal subsurface flow constructed wetlands, and vertical subsurface flow constructed wetlands. However, traditional wetlands cannot effectively enhance nitrogen and phosphorus removal or organic matter removal. Summary of the Invention

[0005] 1. The technical problem that the invention aims to solve

[0006] To address the shortcomings and deficiencies of existing technologies, this invention provides a composite circulating constructed wetland effluent treatment system and method. This invention combines three wetland systems and enhances the circulating surface flow wetland. The functional zoning is reasonable. The effluent first enters the vertical subsurface flow wetland and the horizontal subsurface flow wetland to enhance the removal of various types of organic matter, nitrogen, phosphorus and other pollutants. Subsequently, it enters the surface flow wetland, where submerged plants at the bottom and emergent plants at the surface work together to enhance water quality purification and improve the effluent purification effect.

[0007] 2. Technical Solution

[0008] To achieve the above objectives, the technical solution provided by the present invention is as follows:

[0009] The present invention discloses a composite circulating constructed wetland tailwater treatment system, comprising a vertical subsurface flow wetland, a horizontal subsurface flow wetland, and a surface flow wetland. The vertical subsurface flow wetland is provided with an inlet pipe at its input end, and a water distribution main pipe is connected to the output end of the inlet pipe. The water distribution main pipe is laid at the bottom of the vertical subsurface flow wetland, and a water distribution perforated pipe is connected to the output end of the water distribution main pipe. A first layer of packing material is provided inside the vertical subsurface flow wetland. A collection pipe is provided at the output end of the vertical subsurface flow wetland, and a collection channel is connected to the output end of the collection pipe. A horizontal subsurface flow wetland is provided at the output end of the collection channel.

[0010] The input end of the horizontal subsurface flow wetland is connected to the collection channel through a water distribution through-pipe. The horizontal subsurface flow wetland is equipped with a second layer of packing material. The output end of the horizontal subsurface flow wetland is connected to the water collection channel through a perforated collection pipe. The output end of the water collection channel is equipped with an outlet pipe, one end of which extends into the surface flow wetland.

[0011] The bottom of the surface flow wetland is planted with submerged plants, and the interior of the surface flow wetland is equipped with flow promoters at intervals. The outlet of the surface flow wetland is equipped with a tailwater discharge main pipe.

[0012] Furthermore, emergent aquatic plants are planted in the vertical subsurface flow wetlands, horizontal subsurface flow wetlands, and surface flow wetlands.

[0013] Furthermore, the output end of the perforated collection pipe is provided with an adjustable water outlet.

[0014] Furthermore, the surface flow wetland is annular.

[0015] Furthermore, multiple sets of vertical and horizontal subsurface flow wetlands can be arranged side by side within the inner ring of the surface flow wetland.

[0016] Furthermore, the total thickness of the first multi-layer filler is 150cm, consisting of a 40cm thick layer of pebbles with a particle size of 50-80mm, a 60cm thick layer of biomass filler with a particle size of 30-50mm, a 30cm thick layer of biomass filler with a particle size of 10-30mm, and a 20cm thick layer of rubble with a particle size of 5-8mm.

[0017] Furthermore, the total thickness of the second multilayer packing is 140cm, consisting of a 40cm thick gravel layer with a particle size of 20-40mm, a 40cm thick biomass packing layer with a particle size of 10-30mm, a 40cm thick zeolite layer with a particle size of 20-40mm, and a 20cm thick gravel layer with a particle size of 5-10mm from bottom to top.

[0018] A method for treating wastewater from a composite circulating constructed wetland includes the following steps:

[0019] Step 1: The wastewater to be treated is fed into the distribution main pipe through the inlet pipe set in front of the vertical subsurface flow wetland, and then the water is evenly distributed through the perforated distribution pipe. The water flows up to the surface of the vertical subsurface flow wetland through the first multi-layer packing material, and after passing through the surface emergent plants, the wastewater enters the collection channel through the collection pipe.

[0020] Step 2: The tailwater in the collection channel is evenly distributed into the horizontal subsurface flow wetland through the water distribution pipe. The water flows horizontally through the second layer of filler material. With the combined action of emergent plants on the water surface, the water flows to the vicinity of the end collection channel. The tailwater is then collected through the perforated collection pipe and enters the collection channel through the adjustable outlet. Subsequently, the tailwater enters the surface flow wetland through the outlet pipe.

[0021] Step 3: The tailwater entering the surface flow wetland of the circulation channel is propelled by the propeller, and the submerged plants at the bottom and the emergent plants on the surface work together to finally discharge the tailwater into the designated water body through the tailwater discharge main pipe.

[0022] 3. Beneficial effects

[0023] Compared with the prior art, the technical solution provided by this invention has the following advantages:

[0024] In this invention, a vertical subsurface flow wetland, a horizontal subsurface flow wetland, and a surface flow wetland are connected in series. The effluent first passes through the water distribution unit of the vertical subsurface flow wetland, and then through the first multi-layer packing material from bottom to top. The effluent, after initial purification, enters the perforated pipe water distribution unit of the horizontal subsurface flow wetland and flows horizontally through the second multi-layer packing material. The effluent, after further purification, is discharged into a circulating plug flow surface flow wetland. In the surface flow wetland, the effluent is further purified by emergent and submerged plants and aquatic animals. This invention combines three wetland systems and enhances the effect of effluent purification in the circulating surface flow wetland.

[0025] The composite circulating constructed wetland process of this invention has a short flow rate and reasonable functional zoning. The effluent first enters the vertical subsurface flow wetland and the horizontal subsurface flow wetland to enhance the removal of various types of organic matter, nitrogen, phosphorus and other pollutants. Subsequently, it enters the surface flow wetland, where submerged plants on the bottom and emergent plants on the surface work together to enhance water purification. The water surface is large, the plant community is rich, and the landscape creation effect is good. Attached Figure Description

[0026] Figure 1 This is a top view of the present invention;

[0027] Figure 2 This is a cross-sectional view of the present invention.

[0028] In the diagram: 1. Vertical subsurface flow wetland; 101. Inlet pipe; 102. Distribution main pipe; 103. Distribution perforated pipe; 104. First multi-layer packing material; 105. Collection pipe; 106. Collection channel; 2. Horizontal subsurface flow wetland; 201. Distribution through pipe; 202. Second multi-layer packing material; 203. Perforated collection pipe; 2031. Adjustable outlet; 204. Collection channel; 205. Outlet pipe; 3. Surface flow wetland; 301. Submerged plants; 302. Flow generator; 303. Tailwater discharge main pipe; 4. Emergent plants on the water surface. Detailed Implementation

[0029] The present invention will be further described below with reference to the accompanying drawings and embodiments:

[0030] Example 1

[0031] from Figure 1-2 As can be seen, the composite circulating constructed wetland tailwater treatment system of this embodiment includes a vertical subsurface flow wetland 1, a horizontal subsurface flow wetland 2, and a surface flow wetland 3. The input end of the vertical subsurface flow wetland 1 is provided with an inlet pipe 101, and the output end of the inlet pipe 101 is connected to a water distribution main pipe 102. The water distribution main pipe 102 is laid at the bottom of the vertical subsurface flow wetland 1, and the output end of the water distribution main pipe 102 is connected to a water distribution perforated pipe 103. The vertical subsurface flow wetland 1 is provided with a first multi-layer packing material 104. The output end of the vertical subsurface flow wetland 1 is provided with a collection pipe 105, and the output end of the collection pipe 105 is connected to a collection channel 106. The output end of the collection channel 106 is provided with a horizontal subsurface flow wetland 2.

[0032] The input end of the horizontal subsurface flow wetland 2 is connected to the collection channel 106 through the water distribution through pipe 201. The horizontal subsurface flow wetland 2 is equipped with a second multi-layer packing material 202. The output end of the horizontal subsurface flow wetland 2 is connected to the collection channel 204 through the perforated collection pipe 203. The output end of the perforated collection pipe 203 is equipped with an adjustable outlet 2031. The output end of the collection channel 204 is equipped with an outlet pipe 205. One end of the outlet pipe 205 extends into the surface flow wetland 3.

[0033] Submerged plants 301 are planted at the bottom of the surface flow wetland 3, and flow promoters 302 are installed at intervals inside the surface flow wetland 3. A tailwater discharge main pipe 303 is installed at the output end of the surface flow wetland 3.

[0034] Emergent aquatic plants 4 are planted on the vertical subsurface flow wetland 1, the horizontal subsurface flow wetland 2, and the surface flow wetland 3.

[0035] The surface flow wetland 3 is ring-shaped, and multiple sets of vertical subsurface flow wetland 1 and horizontal subsurface flow wetland 2 can be set up side by side in the inner ring of the surface flow wetland 3.

[0036] The first multi-layer filler 104 has a total thickness of 150cm. From bottom to top, it consists of a 40cm thick layer of pebbles with a particle size of 50-80mm, a 60cm thick layer of biomass filler with a particle size of 30-50mm, a 30cm thick layer of biomass filler with a particle size of 10-30mm, and a 20cm thick layer of rubble with a particle size of 5-8mm.

[0037] The second multi-layer packing material 202 has a total thickness of 140cm. From bottom to top, it consists of a gravel layer with a particle size of 20~40mm (40cm thick), a biomass packing layer with a particle size of 10~30mm (40cm thick), a zeolite layer with a particle size of 20~40mm (40cm thick), and a gravel layer with a particle size of 5~10mm (20cm thick).

[0038] Example 2

[0039] from Figure 1-2 As can be seen, the method of a composite circulating constructed wetland effluent treatment system in this embodiment includes the following steps:

[0040] Step 1: The wastewater to be treated is fed into the water distribution main pipe 102 through the inlet pipe 101 set in front of the vertical subsurface flow wetland 1, and then the water is evenly distributed through the water distribution perforated pipe 103. The water flows up to the surface of the vertical subsurface flow wetland 1 through the first multi-layer packing 104, and after passing through the surface emergent plants 4, the wastewater enters the collection channel 106 through the collection pipe 105.

[0041] Step 2: The tailwater in the collection channel 106 is evenly distributed into the horizontal subsurface flow wetland 2 through the water distribution pipe. The water flows horizontally through the second multi-layer packing material 202. Under the combined action of the emergent plants 4 on the water surface, the water flows to the vicinity of the end collection channel 204. The tailwater is then collected through the perforated collection pipe 203 and enters the collection channel 204 through the adjustable outlet 2031. Subsequently, the tailwater enters the surface flow wetland 3 through the outlet pipe 205.

[0042] Step 3: The tailwater entering the surface flow wetland 3 of the circulation channel is driven by the propeller 302, and the submerged plants 301 at the bottom of the water and the emergent plants 4 on the water surface work together to finally discharge the tailwater into the designated water body through the tailwater discharge main pipe 303.

[0043] This invention addresses the shortcomings of current single vertical or horizontal subsurface flow constructed wetland technologies or surface flow wetland technologies by providing a composite treatment system of vertical subsurface flow + horizontal subsurface flow + circulating surface flow constructed wetlands, which has strong nitrogen and phosphorus removal capabilities, high organic matter removal efficiency, and strong resistance to shock loads.

[0044] Vertical subsurface flow wetland 1, horizontal subsurface flow wetland 2, and surface flow wetland 3 are connected in series. The effluent first passes through the water distribution unit of vertical subsurface flow wetland 1, and then through the first multi-layer packing 104 from bottom to top. The effluent after initial purification is collected and then enters the perforated pipe water distribution unit of horizontal subsurface flow wetland 2. It flows horizontally through the second multi-layer packing 202, and the effluent after further purification is discharged into the circulating plug flow surface flow wetland 3. In the surface flow wetland 3, the effluent is further purified by emergent and submerged plants and aquatic animals. This invention combines three wetland systems and strengthens them in the circulating surface flow wetland to improve the effluent purification effect.

[0045] The composite circulating constructed wetland process of this invention has a short flow rate and reasonable functional zoning. The effluent first enters the vertical subsurface flow wetland 1 and the horizontal subsurface flow wetland 2 to enhance the removal of various types of organic matter, nitrogen, phosphorus and other pollutants. Subsequently, it enters the surface flow wetland 3, where the submerged plants 301 at the bottom of the water and the emergent plants 4 on the water surface work together to enhance the purification of water quality. The water surface is large, the plant community is rich, and the landscape creation effect is good.

[0046] The present invention and its embodiments have been described above illustratively. This description is not restrictive, and the figures shown are only one embodiment of the present invention; the actual structure is not limited thereto. Therefore, if those skilled in the art are inspired by this description and design similar structures and embodiments without departing from the spirit of the present invention, such designs should fall within the protection scope of the present invention.

Claims

1. A composite circulating constructed wetland tail water treatment method, which is realized by a composite circulating constructed wetland tail water treatment system, the system comprising a vertical subsurface flow wetland (1), a horizontal subsurface flow wetland (2) and a surface flow wetland (3), characterized in that: The input end of the vertical subsurface flow wetland (1) is provided with a water inlet pipe (101), the output end of the water inlet pipe (101) is connected with a water distribution main pipe (102), the output end of the water distribution main pipe (102) is connected with a water distribution perforated pipe (103), the vertical subsurface flow wetland (1) is provided with a first multi-layer filler (104), the output end of the vertical subsurface flow wetland (1) is provided with a collecting pipe (105), the output end of the collecting pipe (105) is connected with a collecting channel (106), and the output end of the collecting channel (106) is provided with a horizontal subsurface flow wetland (2). The input end of the horizontal subsurface flow wetland (2) is connected with the collecting channel (106) through the water distribution perforated pipe (201), the horizontal subsurface flow wetland (2) is provided with a second multi-layer filler (202), and the output end of the horizontal subsurface flow wetland (2) is connected with a water collecting channel (204) through the perforated collecting pipe (203), the output end of the water collecting channel (204) is provided with a water outlet pipe (205), and one end of the water outlet pipe (205) extends into the surface flow wetland (3). The bottom of the surface flow wetland (3) is planted with submerged plants (301), the surface flow wetland (3) is provided with a flow pusher (302) at intervals, and the output end of the surface flow wetland (3) is provided with a tail water discharge main pipe (303). The method comprises the following steps: Step one: the tail water to be treated is input into the water distribution main pipe (102) through the water inlet pipe (101) arranged in front of the vertical subsurface flow wetland (1), then is uniformly distributed through the water distribution perforated pipe (103), flows upwards to the surface of the vertical subsurface flow wetland (1) through the first multi-layer filler (104), and then, after the action of the water surface emergent plant (4) on the surface, the tail water enters the collecting channel (106) through the collecting pipe (105); Step two: the tail water in the collecting channel (106) is uniformly distributed into the horizontal subsurface flow wetland (2) through the water distribution perforated pipe, flows horizontally through the second multi-layer filler (202), and flows to the vicinity of the tail water collecting channel (204) under the joint action of the water surface emergent plant (4), then, the tail water is collected through the perforated collecting pipe (203) and enters the water collecting channel (204) through the adjustable water outlet (2031), and then, the tail water enters the surface flow wetland (3) through the water outlet pipe (205); Step three: the tail water entering the surface flow wetland (3) is pushed by the flow pusher (302), and the submerged plants (301) at the bottom and the water surface emergent plant (4) jointly act on the tail water, and finally, the tail water is discharged to a specified water body through the tail water discharge main pipe (303).

2. The composite type cyclic constructed wetland tail water treatment method according to claim 1, characterized in that: The vertical subsurface flow wetland (1), the horizontal subsurface flow wetland (2) and the surface flow wetland (3) are all planted with the water surface emergent plant (4).

3. The composite type cyclic constructed wetland tail water treatment method according to claim 2, characterized in that: The output end of the perforated collecting pipe (203) is provided with an adjustable water outlet (2031).

4. The composite type cyclic constructed wetland tail water treatment method according to claim 3, characterized in that: The surface flow wetland (3) is annular.

5. The composite type cyclic constructed wetland tail water treatment method according to claim 4, characterized in that: The vertical subsurface flow wetland (1) and the horizontal subsurface flow wetland (2) can be arranged in parallel in the inner ring of the surface flow wetland (3).

6. The composite type cyclic constructed wetland tail water treatment method according to claim 1, characterized in that: The first multi-layer filler (104) has a total thickness of 150 cm, and is sequentially composed of a pebble layer with a thickness of 40 cm and a particle size of 50-80 mm, a biomass filler layer with a thickness of 60 cm and a particle size of 30-50 mm, a biomass filler layer with a thickness of 30 cm and a particle size of 10-30 mm, and a sheet stone layer with a thickness of 20 cm and a particle size of 5-8 mm from bottom to top.

7. The composite type of a recirculating constructed wetland tail water treatment method according to claim 1, characterized in that: The second multi-layer filler (202) has a total thickness of 140 cm, and is sequentially composed of a gravel layer with a thickness of 40 cm and a particle size of 20-40 mm, a biomass filler layer with a thickness of 40 cm and a particle size of 10-30 mm, a zeolite layer with a thickness of 40 cm and a particle size of 20-40 mm, and a gravel layer with a thickness of 20 cm and a particle size of 5-10 mm from bottom to top.

8. The method of claim 1, wherein the composite type of the recirculating constructed wetland tail water treatment system is characterized by: The water distribution main pipe (102) is laid at the bottom of the vertical subsurface flow wetland (1).

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