Constructed wetland brackish water treatment device for improving electrode layer configuration

Abstract

The invention discloses a constructed wetland brackish water treatment device for improving electrode layer configuration, and belongs to the field of constructed wetland treatment devices, the constructed wetland brackish water treatment device comprises a main body, a water inlet is arranged at the top end of the side wall of the main body, a water outlet is arranged at the bottom end of the side wall, an anode and a cathode are arranged in the main body, the anode is arranged on one side close to the water inlet, and the cathode is arranged on the other side close to the water outlet. The cathodes are arranged on one side close to the water outlet, and filter materials are filled above the anodes, between the anodes and the cathodes and below the cathodes. According to the invention, the dissolved oxygen content of the anode region of the filter screen type electrode enhanced constructed wetland system with improved electrode layer configuration is increased to about 5mg / L, which is greater than 0.5-1mg / L in a common subsurface flow wetland, so that the problem that the dissolved oxygen concentration of the constructed wetland is gradually reduced under the enhancement action of an electric field is solved; compared with a common electrode enhanced constructed wetland system, the removal rate of total nitrogen, total phosphorus, COD and conductivity is improved by 8-15%, and compared with a traditional vertical subsurface flow constructed wetland, the removal rate of the vertical subsurface flow constructed wetland system is improved by 15-25%.

Description

Technical Field

[0001] The invention belongs to the field of artificial wetland treatment devices, and in particular relates to an artificial wetland brackish water treatment device with an improved electrode layer configuration. Background Art

[0002] In existing electrode-enhanced constructed wetland treatment devices, the conventional electrode layer structure usually adopts plate-shaped or columnar electrodes, and the anode and cathode are alternately arranged in the matrix layer. This structure has the following disadvantages:

[0003] 1. Electrode materials are prone to corrosion:

[0004] Commonly used electrode materials such as graphite, copper, stainless steel, etc. are susceptible to corrosion in complex water environments. Corrosion will reduce the conductivity of the electrode and may cause damage to the electrode structure, requiring frequent replacement, thereby increasing the maintenance cost of the system.

[0005] 2. Limited effect of microbial attachment:

[0006] Limited specific surface area: The specific surface area of ​​plate and sheet electrodes is relatively small, which limits the number and area of ​​microorganisms attached, thereby reducing the electron transfer efficiency and pollutant degradation rate. Long electron transfer path: After microorganisms attach, electrons need to pass through a longer path from the microorganisms to the electrode surface, increasing the energy loss in the electron transfer process, further reducing the electrode's power generation performance and pollutant removal efficiency.

[0007] 3. The microbial community structure is difficult to control:

[0008] The microbial community structure inside the artificial wetland is complex, and the types and number of microorganisms in the electrode layer are difficult to effectively control. Many heterotrophic non-electricity-producing microorganisms consume a lot of energy, reducing the power generation performance of the system.

[0009] 4. Uneven electrode layer layout:

[0010] In large-scale constructed wetlands, the distribution of electrodes may be locally dense or sparse, which will lead to uneven electron transfer, resulting in higher microbial activity and pollutant removal efficiency in some areas and lower efficiency in other areas, resulting in unsatisfactory overall treatment effect.

[0011] 5. The stability of the electrode layer decreases:

[0012] During long-term operation, the electrode layer may be displaced or deformed due to factors such as water scouring, microbial metabolic activities, and chemical corrosion, which will affect the efficiency of electron transfer and microbial attachment, thereby reducing the treatment performance of the constructed wetland.

[0013] 6. High energy consumption:

[0014] In order to maintain the electrochemical reaction of the electrode layer, it is necessary to continuously provide electrical energy, especially when treating high-concentration pollutants, the electrical energy consumption is relatively large. High energy consumption will increase the operating cost of artificial wetlands, reduce their economic efficiency, and limit their feasibility in large-scale applications. Summary of the invention

[0015] The object of the present invention is to provide a constructed wetland brackish water treatment device with an improved electrode layer configuration to solve the deficiencies in the prior art.

[0016] In order to achieve the above-mentioned invention object, the technical solution adopted by the present invention is:

[0017] An artificial wetland brackish water treatment device with an improved electrode layer configuration comprises: a main body, a water inlet is arranged at the top end of the side wall of the main body, a water outlet is arranged at the bottom end of the side wall, an anode and a cathode are arranged inside the main body, the anode is arranged on a side close to the water inlet, the cathode is arranged on a side close to the water outlet, and filter material is filled above the anode, between the anode and the cathode, and below the cathode.

[0018] Furthermore, the anode includes: two sheets of first foamed nickel meshes, with a sponge mesh sandwiched between the two sheets of the first foamed nickel meshes.

[0019] Furthermore, the first foamed nickel mesh and the sponge mesh are both covered with domesticated salt-tolerant biofilms.

[0020] Furthermore, the pore size of the first foamed nickel mesh is 5-10ppi.

[0021] Furthermore, the cathode includes: two pieces of second foamed nickel meshes, and manganese sand is sandwiched between the two pieces of the second foamed nickel meshes.

[0022] Furthermore, the pore size of the second foamed nickel mesh is 10-20ppi.

[0023] Furthermore, the filter material is zeolite, activated carbon or quartz sand.

[0024] The artificial wetland brackish water treatment device with improved electrode layer configuration provided by the present invention has the following advantages compared with the prior art:

[0025] The dissolved oxygen content in the anode area of ​​the artificial wetland system enhanced by the filter-type electrode with improved electrode layer configuration is increased to about 5 mg / L, which is greater than the 0.5-1 mg / L in ordinary subsurface flow wetlands. Therefore, it helps to solve the problem of the gradual decrease of dissolved oxygen concentration in artificial wetlands under the action of electric field enhancement.

[0026] The system that uses filter-type electrodes and changes the electrode layer configuration increases the removal rate of total nitrogen, total phosphorus, COD, and conductivity by 8-15% compared to ordinary electrode-enhanced artificial wetland systems, and increases it by 15-25% compared to traditional vertical subsurface flow artificial wetlands. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the embodiments of the present invention 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 embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0028] Figure 1 It is a structural schematic diagram of the present invention.

[0029] In the figure: 1-main body, 2-water inlet, 3-water outlet, 4-first foamed nickel mesh, 5-sponge mesh, 6-second foamed nickel mesh, 7-manganese sand. DETAILED DESCRIPTION

[0030] The technical solution of the present invention is further described below in conjunction with the accompanying drawings and embodiments:

[0031] refer to Figure 1 As shown, the present invention provides a device for treating brackish water in an artificial wetland with an improved electrode layer configuration, comprising: a main body 1, a water inlet 2 is arranged at the top of the side wall of the main body 1, a water outlet 3 is arranged at the bottom of the side wall, an anode and a cathode are arranged inside the main body 1, the anode is arranged on the side close to the water inlet 2, the cathode is arranged on the side close to the water outlet 3, and filter materials are filled above the anode, between the anode and the cathode, and below the cathode. This device is suitable for conventional mine water and weakly mineralized water, and the corresponding mineralization is less than 1000 mg / L and 1000-3000 mg / L, respectively. The water quality is generally neutral, containing trace metal elements or basically no toxic and harmful elements.

[0032] As a preferred embodiment, the anode includes: two sheets of first foamed nickel mesh 4 (preferably with a thickness of 1-2 cm), and a sponge mesh 5 (preferably with a thickness of 3 cm) is sandwiched between the two sheets of the first foamed nickel mesh 4. Filling the anode layer with the sponge mesh 5 helps to prolong the residence time of dissolved oxygen in the anode layer, and also provides a stable living environment for microorganisms. Using part of the sponge mesh 5 as the anode layer can reduce the demand for large nickel mesh and large electric field, effectively reducing costs; at the same time, it can also provide a better living carrier for microorganisms, and its ability to adsorb dissolved oxygen is also stronger.

[0033] As a preferred embodiment, the first foamed nickel mesh 4 and the sponge mesh 5 are both covered with domesticated salt-tolerant biofilms. The microorganisms in the salt-tolerant biofilm can be isolated from the natural environment, for example, salt-tolerant or halophilic microorganisms are isolated from high-salt environments such as seawater, saline-alkali land, and salt lakes, and then cultured and amplified to form a salt-tolerant biofilm. The use of salt-tolerant biofilm technology has many advantages in the treatment of brackish water: 1. The microorganisms therein can remain active in a high-salt environment, effectively degrade pollutants, and have a higher removal load and system stability compared to the activated sludge method. 2. The salt-tolerant biofilm has a compact structure and rich internal protozoa. It can adapt to the impact of high salinity and organic load, increase the turbidity removal rate of brackish water to 61%, make the effluent clearer, and facilitate mud and water separation. 3. The salt-tolerant biofilm can significantly improve the treatment quality of high-salt wastewater, reduce the content of suspended solids and colloids, and reduce the cost of flocculants.

[0034] As a preferred embodiment, the pore size of the first foamed nickel mesh 4 is 5-10 ppi.

[0035] As a preferred embodiment, the cathode includes: two sheets of second foamed nickel mesh 6 (preferably with a thickness of 1-2 cm), and manganese sand 7 is sandwiched between the two sheets of the second foamed nickel mesh 6. The cathode layer is filled with manganese sand 7 to enhance the oxidation-reduction ability of the reaction device. Manganese hydroxide generated by manganese dioxide and water gaining electrons is an important multi-metal ion adsorbent, and is also a commonly used oxidant and catalyst in chemical reactions. (A. Multi-metal ion adsorbent: Manganese hydroxide can effectively adsorb a variety of heavy metal ions in water, such as copper ions (Cu 2+ ), lead ion (Pb 2+ ), zinc ion (Zn 2+ ) etc. This adsorption effect is of great significance for purifying water quality and removing heavy metal pollution in water. Studies have shown that the removal rate of these heavy metal ions by manganese hydroxide adsorbents prepared by a specific synthesis method is close to 100%, which can meet the drinking water standard. B. Oxidant: Manganese dioxide is a strong oxidant. Manganese hydroxide can effectively remove toxic and harmful metal ions in polluted water bodies and oxidize and degrade organic matter such as phenol, 2-propanol, benzene and printing and dyeing wastewater. Its pollution purification ability is mainly based on surface complexation reaction, surface ion exchange and redox effect of variable valence elements. C. Catalyst: Manganese hydroxide, as a catalyst, can effectively remove organic matter in high-salinity wastewater. )

[0036] As a preferred embodiment, the pore size of the second foamed nickel mesh 6 is 10-20 ppi.

[0037] As a preferred embodiment, the filter material is zeolite, activated carbon or quartz sand.

[0038] The foamed nickel mesh has a loose, porous and multi-dimensional structure. When used as an electrode material, it has a larger contact area than ordinary electrode plates, allowing the electric field to have more complete contact with water and the microorganisms therein, thereby losing electrons at the anode and reacting with water to produce more oxygen than ordinary electrode plates. At the same time, more complete contact with microorganisms improves the utilization efficiency of the electric field enhancement effect.

[0039] The foamed nickel mesh has the characteristics of multi-dimensional and irregular distribution, which will produce potential differences of different sizes due to different resistances at different positions, thereby generating weak voltages in different directions in different micropores of the nickel mesh.

[0040] Nickel is a metal with good electrical conductivity, and the electrical conductivity of nickel is 1.43×10^7S / m. High-quality nickel mesh has good electrical conductivity, which can effectively reduce the resistance of the electrode and evenly distribute the current on the electrode surface, thereby increasing the rate of the electrolytic reaction. The conductivity of nickel mesh is better than that of stainless steel and graphite carbon. Specifically, nickel mesh has the best conductivity, followed by stainless steel, and finally graphite carbon.

[0041] Through simulation experiments, it is known that the dissolved oxygen content in the anode area of ​​the artificial wetland system with improved electrode layer configuration is increased to about 5 mg / L, which is greater than the 0.5-1 mg / L in ordinary subsurface flow wetlands, so it helps to solve the problem of gradually decreasing dissolved oxygen concentration in artificial wetlands under the action of electric field enhancement. In addition, the system using filter-type electrodes and changing the electrode layer configuration has increased the removal rate of total nitrogen, total phosphorus, COD, and conductivity by 8-15% compared with the ordinary electrode enhanced artificial wetland system, and increased by 15-25% compared with the traditional vertical subsurface flow artificial wetland.

[0042] In the description of the present application, it should be noted that the terms "upper", "lower", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. Unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be a connection between the two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to the specific circumstances.

[0043] It should be noted that, in this application, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the presence of other identical elements in the process, method, article or device including the elements.

[0044] The above description is only a specific implementation of the present application, so that those skilled in the art can understand or implement the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest range consistent with the principles and novel features applied for herein.

Claims

1. A constructed wetland device for treating brackish water with improved electrode layer configuration, characterized in that: include: A main body (1), wherein a water inlet (2) is arranged at the top end of a side wall of the main body (1), and a water outlet (3) is arranged at the bottom end of the side wall; an anode and a cathode are arranged inside the main body (1), wherein the anode is arranged on a side close to the water inlet (2), and the cathode is arranged on a side close to the water outlet (3); and filter material is filled above the anode, between the anode and the cathode, and below the cathode.

2. The device for treating brackish water by artificial wetland with improved electrode layer configuration according to claim 1, characterized in that: The anode comprises: two sheets of first foamed nickel meshes (4), with a sponge mesh (5) sandwiched between the two sheets of the first foamed nickel meshes (4).

3. The device for treating brackish water by artificial wetland with improved electrode layer configuration according to claim 2, characterized in that: The first foamed nickel net (4) and the sponge net (5) are both covered with domesticated salt-tolerant biofilms.

4. The device for treating brackish water by artificial wetland with improved electrode layer configuration according to claim 2, characterized in that: The pore size of the first foamed nickel mesh (4) is 5-10 ppi.

5. The device for treating brackish water by artificial wetland with improved electrode layer configuration according to claim 1, characterized in that: The cathode comprises: two sheets of second foamed nickel meshes (6), and manganese sand (7) is sandwiched between the two sheets of the second foamed nickel meshes (6).

6. The device for treating brackish water by artificial wetland with improved electrode layer configuration according to claim 5, characterized in that: The pore size of the second foamed nickel mesh (6) is 10-20 ppi.

7. The device for treating brackish water by artificial wetland with improved electrode layer configuration according to claim 1, characterized in that: The filter material is zeolite, activated carbon or quartz sand.

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