Electrically-enhanced constructed wetland

Abstract

The utility model provides an electric strengthening constructed wetland and relates to the technical field of constructed wetlands. The device comprises a plurality of groups of wetland units, wherein each wetland unit comprises a subsurface flow constructed wetland pool body; the packing layer is laid in the subsurface flow constructed wetland pool body, and the electrode layer is laid in the packing layer; the subsurface flow constructed wetland pool body is internally divided into a plurality of grids through a plurality of partition walls, the plurality of partition walls are alternately arranged in the subsurface flow constructed wetland pool body in a high-low mode in the water inlet direction and the water outlet direction respectively, and the adjacent grids are communicated through the lower portion of the partition wall at the high position or the upper portion of the partition wall at the low position. On the whole, multi-stage reoxygenation of sewage is achieved, and then the electron obtaining capacity of the subsequent electrode layer and the degradation effect of ammonia nitrogen and refractory organic matter pollutants on the anode layer are enhanced.

Description

Technical Field

[0001] The utility model relates to the technical field of artificial wetlands, in particular to an electrically enhanced artificial wetland. Background Art

[0002] In order to achieve the goal of deep sewage purification, the industry has developed a number of technologies, including coagulation-high-efficiency sedimentation, contact filtration, ozone catalytic oxidation, and membrane separation. Among them, subsurface artificial wetland technology achieves deep removal of nitrogen, phosphorus, and organic pollutants by constructing an aquatic plant-microorganism ecosystem, using the adsorption and interception of pollutants by fillers, combined with the decomposition and transformation of microorganisms, and the absorption and utilization of plants. It has the advantages of low cost and simple operation, and is a deep sewage purification technology with broad application prospects. After a lot of research and engineering practice, subsurface artificial wetlands have been used in the deep treatment of sewage for COD, NH 3 -N and SS showed stable removal effects, but for soluble TP, NO 3 - -N removal efficiency is low, and the removal effect of new pollutants such as antibiotics needs to be further improved. At present, sewage flow usually adopts a single horizontal flow or vertical flow mode, which has the problem of low reoxygenation rate; the technology mainly targets COD and TN indicators, and lacks design for the coordinated control of TP and new pollutants.

[0003] Therefore, there is an urgent need for an electrically enhanced artificial wetland that can effectively improve the reoxygenation rate and the degradation of TN, TP and new pollutants. Utility Model Content

[0004] The purpose of the utility model is to provide an electrically enhanced artificial wetland, which solves the technical problems of low reoxygenation rate and low degradation effect of TN, TP and new pollutants in the prior art. The preferred technical solution among the many technical solutions provided by the utility model can produce many technical effects as described below.

[0005] In order to achieve the above purpose, the utility model provides the following technical solutions:

[0006] The utility model provides an electrically enhanced artificial wetland, comprising a plurality of groups of wetland units, wherein the wetland units include:

[0007] Subsurface flow artificial wetland pool;

[0008] A packing layer and an electrode layer, wherein the packing layer is laid in the subsurface flow artificial wetland pool, and the electrode layer is laid in the packing layer;

[0009] Partition walls, the subsurface flow artificial wetland pool body is divided into a plurality of grids by a plurality of the partition walls, and the plurality of the partition walls are arranged alternately in the subsurface flow artificial wetland pool body along the water inlet and outlet directions, and the adjacent grids are connected through the bottom of the high partition walls or the top of the low partition walls.

[0010] Preferably, the electrode layer comprises:

[0011] A cathode layer and an anode layer, wherein the cathode layer and the anode layer are sequentially arranged in the packing layer from top to bottom.

[0012] Preferably, the cathode layer or the anode layer comprises:

[0013] A frame bracket, wherein the frame bracket is arranged in the packing layer;

[0014] Electrode plates, a plurality of said electrode plates are installed in said frame bracket at equal distances.

[0015] Preferably, the electrode layer further comprises:

[0016] Conductive metal-modified biochar, wherein the conductive metal-modified biochar is laid around the frame bracket and the electrode plate.

[0017] Preferably, the electrode plate is made of graphite plate or carbon felt.

[0018] Preferably, the filler layer includes a surface filler, an intermediate filler layer, and a support layer which are arranged in sequence from top to bottom, the cathode layer is arranged between the surface filler and the intermediate filler layer, and the anode layer is arranged between the intermediate filler layer and the support layer.

[0019] Preferably, the surface filler and the middle filler layer are made of at least one of volcanic rock, artificial ceramsite and pyrite.

[0020] Preferably, the supporting layer is made of at least pebbles or gravels.

[0021] Preferably, the partition wall located at a high position is located above the supporting layer and is higher than the surface filler and the water surface, and the partition wall located at a low position is inserted into the bottom of the supporting layer and is lower than the surface filler and the water surface.

[0022] Preferably, it also includes:

[0023] Aquatic plants are planted in the water surface above the filler layer.

[0024] In the technical solution provided by the utility model, the residual NH 3 -N, NO 3 --N, TP and difficult-to-degrade organic matter are removed in this process; the main function of the partition wall is to guide the sewage to flow from top to bottom and from bottom to top. In this process, the water flow is guided to form vertical up and down flow, and contact with the air through the overlying water layer above the artificial wetland filler layer, so as to realize multi-stage reoxygenation of sewage, thereby enhancing the electron-acquisition capacity of the subsequent electrode layer and the degradation effect of ammonia nitrogen and difficult-to-degrade organic pollutants in the electrode layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0026] Figure 1 It is a schematic diagram of a wetland unit of the utility model;

[0027] Figure 2 It is a schematic diagram of the electrode structure of the utility model;

[0028] Figure 3 It is a schematic diagram of a single group of grids of the utility model.

[0029] In the figure, 1, subsurface flow artificial wetland pool; 2, water inlet distribution pipe; 3, surface filler; 4, cathode layer; 5, middle filler layer; 6, anode layer; 7, supporting layer; 8, aquatic plants; 9, outlet weir; 10, outlet pipe; 11, partition wall; 12, frame bracket; 13, electrode plate. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical solution and advantages of the utility model clearer, the technical solution of the utility model will be described in detail below. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other implementation methods obtained by ordinary technicians in this field without creative work belong to the scope of protection of the utility model.

[0031] refer to Figure 1-3 The specific embodiment of the utility model provides an electrically enhanced artificial wetland, including a plurality of groups of wetland units, wherein the wetland units include:

[0032] The subsurface artificial wetland pool body 1, the periphery of the subsurface artificial wetland pool body 1 can be constructed of reinforced concrete or brickwork, or can be constructed of plain soil plus anti-seepage materials;

[0033] A packing layer and an electrode layer, wherein the packing layer is laid in the subsurface flow artificial wetland pool body 1, and the electrode layer is laid in the packing layer;

[0034] Partition walls 11, the subsurface flow artificial wetland pool body 1 is divided into a plurality of grids by a plurality of partition walls 11, and the plurality of partition walls 11 are alternately arranged in the subsurface flow artificial wetland pool body 1 along the water inlet and outlet directions, and adjacent grids are connected through the bottom of the high partition wall 11 or the top of the low partition wall 11.

[0035] At present, sewage flow usually adopts a single horizontal flow or vertical flow mode, which has the problem of low reoxygenation rate; the technology mainly targets COD and TN indicators, and lacks the design of coordinated control of TP and new pollutants. In this application, the residual NH in the sewage can be removed after passing through the packing layer and the electrode layer. 3 -N, NO 3 - -N, TP and difficult-to-degrade organic matter are removed in this process through adsorption and biodegradation; the main function of the partition wall 11 is to guide the sewage to flow from top to bottom and from bottom to top. In this process, the water flow is guided to form vertical up-and-down deflections, and the water is in contact with the air through the overlying water layer above the artificial wetland filler layer, so as to realize multi-stage reoxygenation of the sewage, thereby enhancing the electron-acquisition capacity of the subsequent electrode layer and the degradation effect of ammonia nitrogen and difficult-to-degrade organic pollutants in the electrode layer.

[0036] Further optimizing the scheme, the electrode layer includes:

[0037] The cathode layer 4 and the anode layer 6 are arranged in sequence in the packing layer from top to bottom.

[0038] In a further optimized solution, the cathode layer 4 or the anode layer 6 comprises:

[0039] A frame bracket 12, the frame bracket 12 is arranged in the packing layer, and the frame bracket 12 includes a plurality of sets of plates connected end to end;

[0040] The electrode plates 13 are installed in the frame bracket 12 at equal distances. The electrode plates 13 are made of graphite plates or carbon felt.

[0041] In order to solve the problem of accumulation of functional materials as particle electrodes, pore clogging and decreased surface group activity after long-term contact with sewage, which leads to poor uniformity of conductivity inside the electrode layer, the utility model adopts a carbon electrode with high conductivity as the electrode plate 13, and graphite plates, carbon felt, etc. can be used as collectors arranged horizontally at equal intervals to assemble into an electrode assembly to improve the conductivity of the electrode layer; the thickness of the electrode plate 13 is 3-5mm, the distance between adjacent electrode plates 13 is 150-300mm, and the width of the electrode plate 13 is 10-15mm.

[0042] Further optimizing the solution, the electrode layer also includes:

[0043] Conductive metal-modified biochar, the conductive metal-modified biochar is laid around the frame bracket 12 and the electrode plate 13 .

[0044] Conductive metal-modified biochar is prepared by high-temperature pyrolysis of biochar and loading of variable-valence active metals. Different from the general biochar preparation method, it increases the content of biochar graphite structure through high-temperature 800-900°C anaerobic pyrolysis, thereby improving the conductivity of the material; at the same time, it retains certain oxygen-containing functional groups, and then increases the surface redox ability of biochar through loading of variable-valence active metal oxides, thereby improving the pseudocapacitance of the material; the overall conductivity and electron transfer ability of the material are improved; the particle size of the conductive metal-modified biochar is 5-6mm.

[0045] A further optimized solution is that the packing layer includes a surface packing 3, an intermediate packing layer 5, and a supporting layer 7 which are arranged in sequence from top to bottom, the cathode layer 4 is arranged between the surface packing 3 and the intermediate packing layer 5, and the anode layer 6 is arranged between the intermediate packing layer 5 and the supporting layer 7, wherein the surface packing 3 and the intermediate packing layer 5 are made of at least one of volcanic rock, artificial expanded clay, and pyrite; the supporting layer 7 is made of at least one of pebbles and gravel, with a particle size of 10-15mm; except for the particle size of 3-4mm of the surface packing 3 in the first grid along the inlet and outlet directions, the particle sizes of the surface packing 3 in other grids are all 5-6mm.

[0046] According to a further optimization scheme, the partition wall 11 located at a high position is located above the supporting layer 7 and is higher than the surface filler 3 and the water surface, and the partition wall 11 located at a low position is inserted into the bottom of the supporting layer 7 and is lower than the surface filler 3 and the water surface.

[0047] Further optimization plans also include:

[0048] Aquatic plants 8 are planted in the water surface above the filler layer; the aquatic plants 8 may be reeds, calamus, irises, lilies, and the like.

[0049] To further optimize the scheme, the width B of each group of grids is 1-10m, and should not exceed 10m. When the width exceeds 3m, it is recommended to add a bottom perforated pipe for water collection; the length-to-width ratio L / B of each group of grids should be 1:1-1:1.5; a single group of wetland units is set with 4-8 grids along the flow direction;

[0050] The effective depth H of each wetland unit should be 1-1.5m, of which the overlying water layer is 50-100mm; the surface filler 3 is 100-200mm deep; the cathode layer 4 is 150-200mm deep; the middle filler layer 5 is 400-500mm deep; the anode layer 6 is 200-300mm deep; and the supporting layer 7 is 150-200mm deep.

[0051] In general, the operation process of this application is far from pollutant degradation as follows:

[0052] The secondary effluent of the sewage after biological treatment can enter the subsurface artificial wetland of the utility model. The raw water is evenly distributed through the water distribution pipe of the subsurface artificial wetland pool 1, forming a water layer on the surface of the first grid of the wetland, which contacts with the air to increase the oxygen content. Then the downflow method goes downward through the surface filler 3, cathode layer 4, middle filler layer 5, anode layer 6 and support layer 7 in turn. The residual NH3-N and NO in the sewage 3 - -N, TP and refractory organic matter are removed in this process. 3 When -N passes through the surface filler 3, cathode layer 4 and middle filler layer 5, the nitrifying bacteria attached to the surface of the material use the dissolved oxygen (DO) in the water to convert it into NO 3 - -N; after entering the anode layer 6, NH 3 -N is oxidized by the electroactive bacteria attached to the surface of the conductive filler, and the remaining electrons are collected by the collector and then transferred to the cathode layer 4 on the surface through the external circuit. 3 - When N passes through the cathode layer, it is reduced to N by the electroactive bacteria attached to the surface of the conductive filler using the electrons transferred by the anode layer 6 through the external circuit. 2 ; When passing through the middle filler layer 5 and the anode layer 6 in turn, the denitrifying bacteria attached to the surface use the residual organic matter in the water to reduce it to N 2 TP is mainly fixed by high-capacity phosphorus adsorption ceramsite filled in the middle filler layer 5 through chemical adsorption; the difficult-to-degrade organic matter including new pollutants passes through the surface filler 3, cathode layer 4 and middle filler layer 5, and heterotrophic aerobic bacteria utilize DO in the water and denitrifying bacteria utilize NO in the water 3 - -N acts as an electron acceptor and is oxidized and decomposed; when entering the anode layer 6, it is directly oxidized by the electroactive bacteria attached to the surface of the conductive filler, and the remaining electrons are collected by the collector and then transferred to the cathode layer on the surface through the external circuit. DO is gradually consumed from top to bottom, and the DO concentrations in the lower part of the intermediate filler layer 5, the anode layer 6 and the supporting layer 7 at the bottom of the subsurface flow constructed wetland are relatively low. However, since the external circuit connects the anode layer 6 with the cathode layer 4, the electroactive microorganisms in the anaerobic zone at the bottom can transfer electrons to the electron acceptors on the surface through the external circuit, which strengthens the reaction activity of the bottom microorganisms and increases the depth of the constructed wetland.

[0053] The sewage and remaining pollutants are pushed horizontally to the next grid through the supporting layer 7, and then bend upward to pass through the anode layer 6, the middle filler layer 5, the cathode layer 4 and the surface filler 3 in sequence, and finally flow out of the filler to form surface water, which contacts with the air to achieve reoxygenation. Then, it is pushed backward in sequence according to the above-described process. The sewage is deeply purified step by step.

[0054] Example 1

[0055] A group of electroactive bacteria enhanced subsurface artificial wetlands (a group of wetland units) was constructed with a width of 1m, a length of 5m, an effective depth of 1.05m, and a flow direction divided into four grids, with irises planted on the surface. Filling from bottom to top: pebbles and gravel 200mm deep, particle size 15mm; anode layer 6 conductive metal-modified biochar 150mm deep, particle size 5-6mm, graphite plate electrode collector assembly; phosphorus adsorption modified artificial ceramsite 400mm deep, particle size 5-6mm; cathode layer 4 conductive metal-modified biochar 150mm deep, particle size 5-6mm, graphite plate electrode collector assembly, artificial ceramsite 100mm deep, particle size 5-6mm; surface water depth 50mm; anode layer collector and cathode layer collector are connected by copper wire; the sewage treatment effect of this application corresponds to the treatment group in the table below. The artificial wetland without adding an electrode layer was used as the control group. The effluent from domestic sewage treated by biological treatment equipment is used as the influent of the artificial wetland, and the treatment effects are compared as follows:

[0056]

[0057] The above is only a specific implementation of the utility model, but the protection scope of the utility model is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed by the utility model, which should be included in the protection scope of the utility model. Therefore, the protection scope of the utility model should be based on the protection scope of the claims.

Claims

1. An electrically enhanced artificial wetland, comprising a plurality of wetland units, characterized in that: The wetland unit comprises: Subsurface flow artificial wetland pool (1); A packing layer and an electrode layer, wherein the packing layer is laid in the subsurface flow artificial wetland pool (1), and the electrode layer is laid in the packing layer; Partition walls (11), the submerged flow artificial wetland pool (1) is divided into a plurality of grids by a plurality of the partition walls (11), the plurality of the partition walls (11) are arranged alternately in the submerged flow artificial wetland pool (1) along the water inlet and outlet directions, and adjacent grids are connected through the lower part of the high partition wall (11) or the upper part of the low partition wall (11).

2. The electrically enhanced artificial wetland according to claim 1, characterized in that: The electrode layer comprises: A cathode layer (4) and an anode layer (6), wherein the cathode layer (4) and the anode layer (6) are arranged in sequence in the packing layer from top to bottom.

3. The electrically enhanced artificial wetland according to claim 2, characterized in that: The cathode layer (4) or the anode layer (6) comprises: A frame bracket (12), wherein the frame bracket (12) is arranged in the packing layer; Electrode plates (13), a plurality of the electrode plates (13) are installed at equal distances in the frame bracket (12).

4. The electrically enhanced artificial wetland according to claim 3, characterized in that: The electrode layer further comprises: Conductive metal-modified biochar, wherein the conductive metal-modified biochar is laid around the frame support (12) and the electrode plate (13).

5. The electrically enhanced artificial wetland according to claim 3, characterized in that: The electrode plate (13) is made of graphite plate or carbon felt.

6. The electrically enhanced artificial wetland according to claim 2, characterized in that: The filler layer comprises a surface filler (3), an intermediate filler layer (5), and a support layer (7) which are arranged in sequence from top to bottom; the cathode layer (4) is arranged between the surface filler (3) and the intermediate filler layer (5); and the anode layer (6) is arranged between the intermediate filler layer (5) and the support layer (7).

7. The electrically enhanced artificial wetland according to claim 6, characterized in that: The surface filler (3) and the middle filler layer (5) are made of at least one of volcanic rock, artificial ceramsite and pyrite.

8. The electrically enhanced artificial wetland according to claim 6, characterized in that: The supporting layer (7) is made of at least one of pebbles and gravels.

9. The electrically enhanced artificial wetland according to claim 6, characterized in that: The partition wall (11) located at a high position is located above the supporting layer (7) and is higher than the surface filler (3) and the water surface, and the partition wall (11) located at a low position is inserted into the bottom of the supporting layer (7) and is lower than the surface filler (3) and the water surface.

10. The electrically enhanced artificial wetland according to claim 1, characterized in that: Also includes: Aquatic plants (8), the aquatic plants (8) are planted in the water surface above the filler layer.

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