CN108383232B - Method and device for improving nitrate nitrogen removal efficiency of downward vertical flow constructed wetland - Google Patents
Method and device for improving nitrate nitrogen removal efficiency of downward vertical flow constructed wetland Download PDFInfo
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Abstract
The invention discloses a method and a device for improving nitrate nitrogen removal efficiency of a downstream vertical flow constructed wetland, comprising the following steps: A. sewage continuously enters from the top of the device and is uniformly distributed; B. flowing the sewage into the anode conductive filler layer, and removing nitrate nitrogen heterotrophic denitrification; C. then the sewage flows into the non-conductive filler isolation layer; D. then the sewage flows into a cathode conductive filler layer, and nitrate nitrogen is reduced into nitrogen; E. and finally, the sewage flows out through a drain pipe in the non-conductive packing layer at the bottom, and the total nitrogen in the effluent is removed. The cathode conductive filler layer is respectively connected with the bottom non-conductive filler layer and the non-conductive filler isolation layer, the anode conductive filler layer is respectively connected with the non-conductive filler isolation layer and the upper non-conductive filler layer, wetland plants are planted in the upper part of the non-conductive filler layer, and the anode collector and the cathode collector are connected with an external resistor in a closed circuit mode through an external lead. The method is simple, is convenient to operate, generates electric energy by in-situ utilization, and obviously improves the total nitrogen removal effect of the low C/N sewage.
Description
Technical Field
The invention belongs to the field of sewage treatment, and particularly relates to an operation method for improving the total nitrogen removal efficiency when a microbial fuel cell and a vertical flow artificial wetland coupling system are used for treating low-carbon high-nitrogen sewage (domestic sewage, tail water of a sewage treatment plant, agricultural non-point sources, underground water and the like), and also relates to a device for enhancing the denitrification efficiency of a downward vertical flow artificial wetland by in-situ power generation of sewage.
Background
The low carbon-nitrogen ratio (C/N is less than or equal to 5) is a typical characteristic of tail water (reclaimed water) of a sewage treatment plant in China, the denitrification efficiency is low due to insufficient carbon source in the denitrification process of the traditional biochemical treatment process (such as an activated sludge method, a biofilm method and the like), the effluent quality is difficult to meet the increasingly strict discharge standard requirement, and the ecological water quality difference with the ecological environment requirement is larger. While adding organic carbon sources such as methanol and ethanol can improve the biological denitrification process, the operation cost can be increased.
As an ecological engineering technology with environmental friendliness and low cost, artificial wetland (CW) has gradually become one of the mainstream processes for sewage dispersion treatment and deep purification. Although the constructed wetland system has abundant carbon source supply paths (decomposition of microorganisms and dead plants, plant root secretion, and release of organic matters deposited in a matrix) and denitrification paths (symbiotic aerobic, anaerobic, autotrophic, heterotrophic and other denitrification microorganisms, matrix adsorption, plant absorption and the like), the constructed wetland system has COD/NO for inflow water3 -(5) the problem of limited total nitrogen Removal capacity due to insufficient carbon source is still encountered in the wastewater (Jan Vymazal, Removal of nutrients in variable types of structures of structured wetlands, in Science of the Total Environment, 2007, 48-65.). How to further improve the denitrification efficiency of the artificial wetland is a hotspot and a difficulty of the current international research on the artificial wetland denitrification technology.
MFC denitrification has also received attention from researchers in recent years. The principle is as follows: electrons generated by the oxidizing of organic substances by the electrogenic bacteria in the anode are transferred to the cathode through an external circuit, and reduction reaction is performed between the nitrate in the cathode and protons transferred from the anode chamber, so that the nitrate is reduced into nitrogen.
MFC denitrification is greatly affected by the mode of operation and operating parameters. If DO affects cathodic denitrification in aerobic and anaerobic organisms differently, it can preferentially become the primary electron acceptor for the cathode because the reduction potential of oxygen is higher than that of nitrate nitrogen. Therefore, DO is maintained at low levels (< 0.5 mg/L) in anaerobic biocathode MFC denitrification.
While the aerobic cathode MFC denitrification mainly takes place the synchronous nitrification and denitrification process, in order to make the surface layer microorganism of the biomembrane take place the nitrification and oxidize ammonia nitrogen into nitrate nitrogen, DO can not be too low (Virdis B., et al., Simultaneous outnification, denitrification and carbon removal in microbial fuel cells Water Research, 2010,44(9): 2970-.
The artificial wetland-microbial fuel cell coupling system is gradually applied to sewage treatment in recent years due to low cost. Although studies have reported that CW-MFC has a good effect for treating high-nitrogen wastewater (Oon et al, Hybrid system-flow-controlled wet and integrated with microbial fuel cell for sewage treatment and electric generation, Bioresource technology, 2015, 186: 270-. Aiming at low carbon and high carbon
Compared with the prior art, the invention has the following advantages and effects: how to realize the high-efficiency denitrification of a CW-MFC system under the condition of no need of mechanical aeration is also one of the current research difficulties.
Disclosure of Invention
The invention aims to provide an operation method for improving the total nitrogen removal efficiency of a downstream vertical flow constructed wetland-microbial fuel cell (DFCW-MFC) system for treating low-carbon high-nitrate nitrogen (such as tail water, surface water and underground water of a sewage treatment plant).
The invention also aims to provide a device for improving the total nitrogen removal efficiency of the low-carbon high-nitrate nitrogen sewage treated by the downward vertical flow artificial wetland-microbial fuel cell system, which has the advantages of simple structure and convenient assembly, and can obviously improve the denitrification effect of the downward vertical flow artificial wetland under the condition of organic carbon source deficiency.
In order to achieve the purpose, the invention adopts the following technical measures:
through the embedding of the microbial fuel cell and the downward vertical flow artificial wetland, the external resistance is adjusted, so that the system is enriched with more abundant and diversified microorganisms with electricity generation and denitrification functions in the anode region and the cathode region under stable current density, and nitrate nitrogen is finally converted into nitrogen to be removed by utilizing electric energy in situ.
The technical scheme is as follows: based on the structure of the downward vertical flow artificial wetland, wetland plants, connecting wires and external resistors are planted through the buried cathode conductive filler layer and the anode conductive filler layer, so that the microbial fuel cell-downward vertical flow artificial wetland coupling configuration is formed. Adjusting external resistance, and strengthening the removal of total nitrogen by the system through the microorganisms with the electricity generation and denitrification functions enriched in the electrode area under stable current.
A method for improving nitrate nitrogen removal efficiency of a downward vertical flow constructed wetland comprises the following steps:
A. sewage continuously enters from the top of the system and is uniformly distributed, the sewage sequentially flows into the upper non-conductive packing layer, plant root systems are mainly distributed on the middle upper part of the layer, the layer is mainly in an aerobic state due to the oxygen secretion action of root systems of wetland plants and dissolved oxygen brought in by inlet water, part of ammonia nitrogen is converted into nitrate nitrogen under the action of nitrobacteria and nitrosobacteria, and a small part of nitrate nitrogen is reduced into nitrogen by the heterotrophic denitrifying bacteria by using an organic carbon source as an electron donor;
B. b, enabling the sewage after the step A to flow into an anode conductive filler layer, enabling part of organic matters to be utilized by electrochemical active bacteria to generate electrons on the layer, enabling the unoxidized organic matters to be basically and completely removed on the layer, and further removing part of nitrate nitrogen through heterotrophic denitrification under the action of the anodic denitrogenation bacteria;
C. then the sewage flows into a non-conductive filler isolation layer, and the layer mainly has the function of being used as a separator between an anode conductive filler layer and a cathode conductive filler layer;
D. then the sewage flows into the cathode conductive filler layer, electrons generated from the anode conductive filler layer in the step b and transferred through an external circuit lead are used as electron donors for reducing nitrate nitrogen, and most of the nitrate nitrogen is reduced into nitrogen gas through autotrophic denitrification and heterotrophic denitrification processes under the action of the cathode denitrogenation.
E. And finally, sewage flows out through a drain pipe in the non-conductive filler layer at the bottom, the total nitrogen content in the effluent is lower than that of the conventional downstream artificial wetland, and the nitrate nitrogen removal rate is improved by 30-60%.
The C/N of the treated sewage is less than or equal to 5 and NO3 -/TN≥60%。
The electrochemical active bacteria are microorganisms with extracellular electron transfer, and comprise Geobacillus (Geobacillus)Geobacter）、Pseudomonas (A)Pseudomonas）、Desulfuromonas (Desulfuromonas) And Rhodococcus (Rhodoferax) And the like or any combination of one to four,
the anodic denitrogenation bacteria belong to nitrifying and denitrifying bacteria with denitrogenation function, including Geobacillus (Geobacillus:)Geobacter) Pseudomonas (a)Pseudomonas）、Genus Soxhlet (A)Thauera) Acinetobacter (A), (B) and (C)Acinetobacter) Zoogloea genus (A)Zoogloea) Genus Microbacterium (A), (B), (C)Exiguobacterium) Flavobacterium (Flavobacterium) andDechloromonasone kind of the above or any combination of one to seven kinds。
The cathodal denitrificans is Geobacillus (A)Geobacter) Genus Soxhlet (A)Thauera) Acinetobacter (A), (B) and (C)Acinetobacter）、DokdonellaBelong to、FerruginibacterAnd the like or any combination of one to five.
The key points of the five steps are that in the steps B and D, electrons are generated from the anode conductive packing layer and migrate to the cathode packing layer through the external circuit lead, and the stable low current density is favorable for enriching more abundant and various microorganisms with the functions of electricity generation and denitrification in the anode region and the cathode region, including autotrophic denitrifying bacteria and heterotrophic denitrifying bacteria, such as the groundBacillus (Geobacter) Pseudomonas (a)Pseudomonas）、Genus Soxhlet (A)Thauera) Acinetobacter (A), (B) and (C)Acinetobacter) Zoogloea genus (A)Zoogloea) Genus Microbacterium (A), (B), (C)Exiguobacterium) And Flavobacterium (Flavobacterium) And the like. The nitrate nitrogen is beneficial to be finally converted into nitrogen gas to be removed, and the removal of the nitrate nitrogen can be stabilized at more than 70%.
A device for improving the nitrate nitrogen removal efficiency of a downward vertical flow constructed wetland is provided with a bottom non-conductive filler layer and a cathode conductive filler layer from bottom to top; a non-conductive filler isolation layer; an anode conductive filler layer; the method is characterized in that: the cathode conductive packing layer is respectively connected with the bottom non-conductive packing layer and the non-conductive packing layer, the anode conductive packing layer is respectively connected with the non-conductive packing layer and the upper non-conductive packing layer, wetland plants are planted in the upper part of the non-conductive packing layer, an anode collector and a cathode collector are connected through an outer lead and an outer resistor to form a closed loop, the anode collector and the cathode collector are respectively placed in the anode conductive packing layer and the cathode conductive packing layer, the outer lead is placed outside the wetland, one end of the outer lead is connected with the anode collector, and the other end of the outer lead is sequentially connected with the outer resistor and the cathode collector.
The device for improving the nitrate nitrogen removal efficiency of the upstream vertical flow constructed wetland is characterized in that:
the fillers in the anode filler layer and the cathode conductive filler layer are granular activated carbon or graphite; the particle diameter of the granular active carbon is 1-5mm, the specific surface area is 500-2(ii) g, the packing density is 0.45-0.55g/cm3(ii) a The graphite particles have a filling particle diameter of 1-5mm and a filling density of 1.8-2g/cm3。
The anode collector and the cathode collector are made of graphite felt, graphite rods or stainless steel.
The filler thickness range of the coupling device of the downward vertical flow artificial wetland and the microbial fuel cell is 60-120 cm.
The thickness of the upper non-conductive filler layer of the device is 20-30cm, the thickness of the anode conductive filler layer is 10-30cm, the thickness of the non-conductive filler isolation layer is 10-20cm, the thickness of the cathode conductive filler layer is 15-30cm, and the thickness of the bottom non-conductive filler layer is 5-10 m.
The non-conductive packing layer on the upper part, the non-conductive packing isolating layer and the non-conductive packing on the bottom part of the device are one or any one to four of gravel, sandstone, anthracite and biological ceramsite;
the wetland plant is one or any combination of one to twelve of canna, pinus, reed, arundo donax linn, sweet grass, cord grass, iris, wild rice stem, lythrata chinensis, wild grass, calamus and elephant grass.
The sewage to be treated has low carbon nitrogen ratio (C/N is less than or equal to 5, NO)3 -and/TN is more than or equal to 60 percent) sewage, including surface water, underground water, tail water of a secondary sewage treatment plant and the like. The total nitrogen removal rate can reach more than 70%.
The treated sewage has a residence time in the apparatus of 20 to 48 hours.
In the above apparatus: 1) the cathode conductive filler layer is respectively connected with the bottom non-conductive filler layer and the non-conductive filler isolation layer, so that the cathode conductive filler layer is in an anaerobic environment to form an anaerobic biological cathode, and nitrate nitrogen is reduced into nitrogen as a preferential electron acceptor. The experimental data show that: when the cathode dissolved oxygen of the anaerobic organisms reaches more than 0.5mg/L, the electricity generation amount is reduced by 60 percent, and the nitrate removal rate is reduced by 50 percent. 2) The anode conductive filler layer is respectively connected with the non-conductive filler isolation layer and the upper non-conductive filler layer, and the plant roots are distributed in the upper non-conductive filler layer, so that the anaerobic environment of the anode conductive filler layer is ensured. 3) The anode collector and the cathode collector are connected through a resistance in a closed circuit through an outer lead, electrons are generated from the anode conductive packing layer and migrate to the cathode packing layer through the outer circuit lead, and the stable low current density is favorable for enriching more abundant and diversified electricity generation and denitrification functional microorganisms in the anode area and the cathode area. The experimental results show that: after the outer lead is connected with a closed-circuit resistor, the number of autotrophic denitrifying bacteria and heterotrophic denitrifying bacteria is increased to 7; wherein the genus Geobacillus: (Geobacter) Pseudomonas (a)Pseudomonas）、Genus Soxhlet (A)Thauera) Acinetobacter (A), (B) and (C)Acinetobacter) Zoogloea genus (A)Zoogloea) Genus Microbacterium (A), (B), (C)Exiguobacterium) And Flavobacterium (Flavobacterium) are respectively increased by 1.5 times, 0.6 times, 6 times, 0.8 times, 1.2 times, 0.8 times and 1.6 times; the removal rate of nitrate nitrogen reaches 70.3 percent.
Compared with the prior art, the invention has the following advantages and effects:
1. on the basis of not changing the structure of the original downward vertical flow wetland, the invention lays the anode conductive filler layer and the cathode conductive filler layer through simple electrode landfill and wire connection, and strengthens the denitrification process under the condition of low organic carbon through enriching the electrogenesis and denitrification functional microorganisms in the anode region and the cathode region under stable current, thereby improving the total nitrogen removal effect of the wastewater with low carbon-nitrogen ratio.
2. The closed circuit formed by the anode conductive filler layer, the cathode conductive filler layer, the external circuit lead and the external resistor utilizes the electric energy generated by the MFC in situ for strengthening denitrification, and compared with a biomembrane electrode-artificial wetland or an electrolytic cell-artificial wetland coupling system, the closed circuit not only does not need an external power supply, but also can obtain the electric energy in the sewage.
Drawings
FIG. 1 is a schematic structural diagram of a device for improving the nitrate nitrogen removal efficiency of a downward vertical flow constructed wetland in situ.
Wherein: 1-bottom non-conductive filler layer; 2-cathode conductive filler layer; 3-a non-conductive filler isolation layer; 4-anode conductive filler layer; 5-upper non-conductive filler layer; 6-wetland plants; 7-anode collector (commercially available); 8-cathode collector (commercially available); 9-outer conductor (normal); 10-external resistance (normal).
Detailed Description
The following description of the embodiments of the present invention is provided in conjunction with the accompanying drawings of FIG. 1, and is not intended to limit the invention thereto.
Example 1:
an operation method for improving nitrate nitrogen removal efficiency of a downward vertical flow constructed wetland comprises the following steps:
A. sewage continuously enters from the top of the system and is uniformly distributed, the sewage sequentially flows into the upper non-conductive packing layer 5, plant root systems are mainly distributed on the middle upper part of the layer, the zone is in an aerobic state due to the oxygen secretion action of root systems of wetland plants and dissolved oxygen brought in by inlet water, part of ammonia nitrogen is converted into nitrate nitrogen under the action of nitrobacteria and nitrosobacteria, and a small part of nitrate nitrogen is reduced into nitrogen by the heterotrophic denitrifying bacteria by using an organic carbon source as an electron donor;
B. b, enabling the sewage after the step a to flow into an anode conductive filler layer 4, enabling part of organic matters to be utilized by electrochemical active bacteria to generate electrons on the layer, enabling the unoxidized organic matters to be basically and completely removed on the layer, and further removing part of nitrate nitrogen through denitrification under the action of anode denitrogenation;
C. then the sewage flows into a non-conductive filler isolation layer 3, and the layer mainly has the function of being used as a separator between an anode conductive filler layer and a cathode conductive filler layer;
D. then the sewage flows into the cathode conductive filler layer 2, electrons generated from the anode conductive filler layer 4 in the step B and transferred by an external circuit lead 9 and an external resistor 10 are used as an electron donor for reducing nitrate nitrogen, and most of nitrate is reduced into nitrogen by autotrophic denitrification and heterotrophic denitrification processes under the action of the cathode denitrificator;
E. and finally, the sewage flows out through a drain pipe in the bottom non-conductive packing layer 1, the nitrate nitrogen content in the effluent is lower than that of the conventional upstream artificial wetland, and the nitrate nitrogen removal is improved by 30-60%.
The sewage is low-carbon and high-nitrogen (COD/TN is less than or equal to 5 and NO is contained in the sewage3 -and/TN is more than or equal to 60 percent) of the characteristic sewage, including surface water, underground water, tail water of a secondary sewage treatment plant and the like.
The electrochemical active bacteria are microorganisms with extracellular electron transfer, and comprise Geobacillus (Geobacillus)Geobacter）、Pseudomonas (A)Pseudomonas）、Desulfuromonas (Desulfuromonas) And Rhodococcus (Rhodoferax) And the like or any combination of one to four,
the anodic denitrogenation bacteria belong to nitrifying and denitrifying bacteria with denitrogenation function, including Geobacillus (Geobacillus:)Geobacter) Pseudomonas (a)Pseudomonas）、Genus Soxhlet (A)Thauera) Acinetobacter (A), (B) and (C)Acinetobacter) Zoogloea genus (A)Zoogloea) Genus Microbacterium (A), (B), (C)Exiguobacterium) Flavobacterium (Flavobacterium) andDechloromonasone kind of the above or any combination of one to eight kinds。
The cathodal denitrificans is Geobacillus (A)Geobacter) Genus Soxhlet (A)Thauera) Acinetobacter (A), (B) and (C)Acinetobacter）、DokdonellaBelong to、FerruginibacterOne or any combination of one to five of the genus
The experimental results show that: after the operation method is adopted, the enrichment of electrogenesis bacteria in the anode area is obviously improved, and the dominant bacteria of Geobacillus (Geobacillus:)Geobacter) The abundance of the polypeptide is improved by 0.8-1.2 times; the diversity of denitrificans is obviously improved, the total abundance is improved by 25-40%, and the denitrificans belongs to the genus Soxhlet (A)Thauera) The abundance is improved by 3-6 times.
Example 2:
a device for improving the nitrate nitrogen removal efficiency of a downward vertical flow constructed wetland is characterized in that a bottom non-conductive filler layer 1 and a cathode conductive filler layer 2 are paved on the structure from bottom to top; a non-conductive filler isolation layer 3; an anode conductive filler layer 4; the method is characterized in that: the cathode conductive packing layer 2 is respectively connected with the bottom non-conductive packing layer 1 and the non-conductive packing layer 3, the anode conductive packing layer 4 is respectively connected with the non-conductive packing layer 3 and the upper non-conductive packing layer 5, wetland plants 6 are planted on the upper portion of the non-conductive packing layer 5, the anode collector 7 and the cathode collector 8 are connected through the outer lead 9 and the outer resistor 10 to form a closed loop, the anode collector 7 and the cathode collector 8 are respectively placed in the anode conductive packing layer 4 and the cathode conductive packing layer 2, the outer lead 9 is placed outside the wetland, one end of the outer lead 9 is connected with the anode collector 7, and the other end of the outer lead 9 is sequentially connected with the outer resistor 10 and the cathode collector 8.
The artificial wet for improving the downward vertical currentThe device for removing the nitrate nitrogen is characterized in that: the fillers in the anode filler layer 4 and the cathode conductive filler layer 2 are granular activated carbon or graphite granules; the particle diameter of the granular activated carbon is 1 or 3 or 5mm, and the specific surface area is 500 or 600 or 700 or 800 or 900m2(ii)/g, the packing density is 0.45 or 0.5 or 0.55g/cm3(ii) a The graphite particles have a packing particle diameter of 1 or 3 or 5mm and a packing density of 1.8 or 1.9 or 2g/cm3。
The wetland plant 6 is one or any combination of one to twelve of canna, pinwheel grass, reed, giant reed, sweet grass, cord grass, iris, wild rice stem, loosestrife, wild grass, calamus and elephant grass.
The anode collector 7 and the cathode collector 8 are made of graphite felt, graphite rods or stainless steel.
The filler thickness range of the device for enhancing the denitrification efficiency of the downward vertical flow constructed wetland by in-situ sewage electrogenesis is 60 or 70 or 80 or 90 or 100 or 110 or 120 cm.
The thickness of the upper non-conductive filler layer 5 is 20 or 25 or 30cm, the thickness of the anode conductive filler layer 4 is 10 or 15 or 20 or 25 or 30cm, the thickness of the non-conductive filler isolation layer 3 is 10 or 15 or 20cm, the thickness of the cathode conductive filler layer 2 is 15 or 20 or 25 or 30cm, and the thickness of the bottom non-conductive filler layer 1 is 5 or 8 or 10 m.
The non-conductive packing layer 1 at the bottom, the non-conductive packing isolation layer 3 and the non-conductive packing layer 5 at the upper part of the device are one or four of gravel, sandstone, anthracite and biological ceramsite.
The sewage is low-carbon and high-nitrogen (COD/TN is less than or equal to 5 and NO is contained in the sewage3 -and/TN is more than or equal to 60 percent) of the characteristic sewage, including surface water, underground water, tail water of a secondary sewage treatment plant and the like. After the treatment by the device, the removal rate of nitrate nitrogen can reach more than 60%.
The treated sewage has a residence time in the apparatus of 20 to 48 hours.
The experimental results show that: compared with the conventional downward vertical flow artificial wetland, the device of the invention can improve the removal rate of nitrate nitrogen by 30-60%.
Claims (7)
1. A method for improving nitrate nitrogen removal efficiency of a downward vertical flow constructed wetland comprises the following steps:
A. sewage continuously enters from the top of the device and is uniformly distributed, the sewage sequentially flows into the upper non-conductive packing layer, plant root systems are distributed on the middle upper part of the layer, the layer is in an aerobic state due to oxygen secretion of root systems of wetland plants and dissolved oxygen brought by inlet water, ammonia nitrogen is converted into nitrate nitrogen under nitrobacteria and nitrosobacteria, and the heterotrophic denitrifying bacteria use an organic carbon source as an electron donor to reduce the nitrate nitrogen into nitrogen;
B. b, enabling the sewage subjected to the step A to flow into an anode conductive filler layer, enabling part of organic matters to be utilized by electrochemical active bacteria to generate electrons on the layer, removing unoxidized organic matters on the layer, and further removing part of nitrate nitrogen through heterotrophic denitrification under the action of the anode denitrogenation bacteria;
C. then the sewage flows into a non-conductive filler isolation layer which is a separator between an anode conductive filler layer and a cathode conductive filler layer;
D. then the sewage flows into a cathode conductive filler layer, electrons generated from the anode conductive filler layer in the step B and transferred through an external circuit lead in the layer are used as electron donors for reducing nitrate nitrogen, and most of the nitrate nitrogen is reduced into nitrogen gas through autotrophic denitrification and heterotrophic denitrification processes under the action of the cathode denitrogenation bacteria;
E. finally, sewage flows out through a drain pipe in the non-conductive filler layer at the bottom, the total nitrogen content in the effluent is higher than that of the conventional downstream artificial wetland, and the total nitrogen removal rate is improved by 30-60%;
the electrochemically active bacteria are microorganisms with extracellular electron transfer, and comprise one or any combination of one to four of Geobacillus, Pseudomonas, Desulfuromonas and Rhodococcus;
the anodic denitrogenation bacteria is nitrifying and denitrifying bacteria, and comprises one or one to three of the Geobacillus, the zoogloea and the azotobacter, and one or any combination of one to three of the acinetobacter, the flavobacterium and the dechloromonas;
the cathodal denitrificans is one or any combination of one to five of geobacter, sorangium, acinetobacter, Dokdonella and Ferrugibacter.
2. The device for improving the nitrate nitrogen removal efficiency of the downward vertical flow constructed wetland according to claim 1 is paved with a bottom non-conductive filler layer (1), a cathode conductive filler layer (2), a non-conductive filler isolation layer (3), an anode conductive filler layer (4) and an upper non-conductive filler layer (5) from bottom to top, and is characterized in that: the cathode conductive packing layer (2) is respectively connected with the bottom non-conductive packing layer (1) and the non-conductive packing layer (3), the anode conductive packing layer (4) is respectively connected with the non-conductive packing layer (3) and the upper non-conductive packing layer (5), wetland plants (6) are planted on the middle upper part of the non-conductive packing layer (5), the anode collector electrode (7) and the cathode collector electrode (8) are connected through an outer lead (9) and an outer resistor (10) to form a closed loop, the anode collector electrode (7) and the cathode collector electrode (8) are respectively placed in the anode conductive packing layer (4) and the cathode conductive packing layer (2), the outer lead (9) is placed outside the wetland, one end of the outer lead (9) is connected with the anode collector electrode (7), and the other end of the outer lead (9) is sequentially connected with the outer resistor (10) and the.
3. The apparatus of claim 2, wherein: the fillers in the anode filler layer (4) and the cathode conductive filler layer (2) are granular activated carbon or graphite granules; the particle diameter of the granular active carbon is 1-5mm, the specific surface area is 500-2(ii) g, the packing density is 0.45-0.55g/cm3(ii) a The graphite particles have a filling particle diameter of 1-5mm and a filling density of 1.8-2g/cm3。
4. The apparatus of claim 2, wherein: the wetland plant (6) is one or any combination of one to twelve of canna, pinwheel grass, reed, bamboo reed, sweet grass, cord grass, iris, wild rice stem, loosestrife, wild grass, calamus and elephant grass.
5. The apparatus of claim 2, wherein: the anode collector (7) and the cathode collector (8) are made of graphite felt, graphite rods or stainless steel.
6. The apparatus of claim 2, wherein: the thickness of the upper non-conductive filler layer (5) is 20-30cm, the thickness of the anode conductive filler layer (4) is 10-30cm, the thickness of the non-conductive filler isolation layer (3) is 10-20cm, the thickness of the cathode conductive filler layer (2) is 15-30cm, and the thickness of the bottom non-conductive filler layer (1) is 5-10 m.
7. The apparatus of claim 2, wherein: the non-conductive packing layer (1) at the bottom, the non-conductive packing isolation layer (3) and the non-conductive packing layer (5) at the upper part of the device are one or four of gravel, sand stone, anthracite and biological ceramsite.
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| CN111777188B (en) * | 2020-07-20 | 2021-09-24 | 中国科学院水生生物研究所 | Method and device for online predicting and slowing down biological blockage of vertical-flow constructed wetland |
| CN111777187B (en) * | 2020-07-20 | 2021-09-24 | 中国科学院水生生物研究所 | Method and device for interactively relieving biological blockage of constructed wetland in situ |
| CN111908612A (en) * | 2020-08-27 | 2020-11-10 | 河海大学 | Artificial wetland coupling system for denitrification of urban sewage |
| CN112299550A (en) * | 2020-10-14 | 2021-02-02 | 武汉轻工大学 | Domestic sewage treatment system and debugging method |
| CN113540542B (en) * | 2021-07-27 | 2023-03-24 | 桂林理工大学 | Microbial battery for constructed wetland |
| CN114162974A (en) * | 2021-12-03 | 2022-03-11 | 哈尔滨工业大学（深圳） | Weak current intervention constructed wetland system for efficiently degrading parachloronitrobenzene and operation method |
| CN114195266A (en) * | 2021-12-03 | 2022-03-18 | 哈尔滨工业大学（深圳） | Low-temperature denitrification enhanced weak current intervention constructed wetland system and operation method thereof |
| CN116002846B (en) * | 2022-12-21 | 2023-11-21 | 山西青舟环境科技有限公司 | A anti-nitrosation wetland for sewage treatment |
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