Construction method and device of constructed wetland ecological buffer zone

Abstract

The invention belongs to the technical field of pollution treatment, and particularly relates to a construction method and device for an ecological buffer zone of a constructed wetland, and the constructed wetland sequentially comprises a first reduction layer of an electrolytic tank, an oxidation layer of the electrolytic tank, a second reduction layer of the electrolytic tank, a reduction layer of a fuel cell and an oxidation layer of the fuel cell from top to bottom. Compared with the prior art, according to the construction method of the constructed wetland ecological buffer zone provided by the invention, denitrification, desulfurization and heavy metal stabilization reactions are completed in the first reduction layer of the electrolytic tank. In addition, the iron-rich biochar is matched with the engineering bacterium agent, 70% of chlorinated aromatic hydrocarbon is removed within 25 days, and compared with traditional natural biodegradation, the removal rate is increased by 60%.

Description

Technical Field

[0001] This invention belongs to the field of pollution treatment technology, specifically relating to a method and apparatus for constructing an artificial wetland ecological buffer zone. Background Technology

[0002] In recent decades, heavy metal pollution has become a major global concern. Heavy metal pollution leads to soil contamination and diffuse pollution, causing serious environmental problems in soil and rivers. Unlike other types of pollution, soil pollution is often more difficult to remediate because heavy metals tend to remain in the soil for extended periods, causing harm to plants and animals. Contaminated soil can no longer be used to grow crops, produce animal feed, or restore forest vegetation, leading to ecological degradation and even desertification.

[0003] Currently, ecological buffer zones are a soil and water conservation measure, consisting of a three-dimensional vegetation strip combining trees, shrubs, and grasses established at the boundary between river channels and land. This area acts as a buffer, controlling air, soil, and water quality, and primarily addresses land issues in agricultural landscapes. Buffer zones can trap sediment and enhance nutrient filtration by slowing runoff, thereby controlling non-point source pollution and protecting and improving water quality.

[0004] However, existing ecological buffer zones are not very effective at removing macromolecular organic pollutants and heavy metals (such as Cr). Currently, constructing an ecological buffer zone capable of removing macromolecular organic pollutants and heavy metals is the primary task for ensuring river and lake ecological flow and maintaining the health of aquatic ecosystems.

[0005] In view of this, the present invention is hereby proposed. Summary of the Invention

[0006] The purpose of this invention is to provide a method and apparatus for constructing artificial wetland ecological buffer zones, so as to solve the technical problems mentioned in the background art.

[0007] To achieve one of the above objectives, the present invention provides the following technical solution:

[0008] A method for constructing an artificial wetland ecological buffer zone, wherein the artificial wetland comprises, from top to bottom:

[0009] The first reduction layer of the electrolytic cell includes an electrolytic cathode; the first reduction layer of the electrolytic cell is filled with soil, steel slag and charcoal filler; DHC engineered bacteria agent is added to the first reduction layer of the electrolytic cell, and plants are also planted on the surface;

[0010] The electrolytic cell oxide layer includes an electrolytic anode; the electrolytic cell oxide layer is filled with Hangjin clay and sodium-based bentonite pads;

[0011] The second reduction layer of the electrolytic cell includes an electrolytic cathode; the second reduction layer of the electrolytic cell is filled with steel slag and charcoal filler.

[0012] The fuel cell reduction layer is filled with aluminosilicate filler; engineered microbial agents are also added to the fuel cell reduction layer.

[0013] The fuel cell oxide layer is filled with gravel and metal-rich biochar.

[0014] Preferably, the thickness of the first reduction layer of the electrolytic cell, the oxide layer of the electrolytic cell, the second reduction layer of the electrolytic cell, the reduction layer of the fuel cell, and the oxide layer of the fuel cell are all 20 cm.

[0015] Preferably, in the first reduction layer of the electrolytic cell, the particle size of the soil, steel slag and charcoal filler is 0.10-0.30 mm, and the mixing ratio is 5:1:4-8:1:1.

[0016] Preferably, in the oxide layer of the electrolytic cell, the particle size of the Hangjin clay and the sodium-based bentonite pad is 1-3 mm, and the mixing ratio is 1:2-1:5.

[0017] Preferably, in the second reduction layer of the electrolytic cell, the particle size of the steel slag and charcoal filler is 5-8 mm, and the mixing ratio is 1:4-1:10.

[0018] Preferably, in the fuel cell reduction layer, the particle size of the aluminosilicate filler is 3-5 mm.

[0019] Preferably, in the fuel cell oxide layer, the particle size of the gravel and the metal-rich biochar is 1-3 mm, and the mixing ratio is 1:5-1:10.

[0020] Preferably, the metal-rich biochar is prepared by the following method:

[0021] Siberian iris plants were planted in a solution of zinc chloride supplemented with one or more of copper chloride, cerium chloride, ferric chloride, and manganese chloride. After two months of cultivation, they were harvested, dried, and crushed. After calcination, biochar loaded with monatomic or coordinated metals was obtained.

[0022] Preferably, in the fuel cell reduction layer, the engineered bacterial agent is an ammonia-oxidizing anaerobic bacteria, sulfate-reducing bacteria and Geothermal bacteria, with a mixing ratio of 2:5:3.

[0023] Preferably, plastic electrodes are arranged in the first reduction layer, the oxidation layer, the second reduction layer, the fuel cell reduction layer, and the fuel cell oxidation layer of the electrolytic cell, respectively. The electrodes in the fuel cell reduction layer and the fuel cell oxidation layer are connected by wires and capacitors, and power is supplied to the first reduction layer, the oxidation layer, and the second reduction layer of the electrolytic cell.

[0024] To achieve the second objective mentioned above, the present invention provides the following technical solution:

[0025] An artificial wetland ecological buffer zone device is constructed using the aforementioned method for constructing an artificial wetland ecological buffer zone.

[0026] Compared with existing technologies, the construction method and apparatus for artificial wetland ecological buffer zones provided by this invention have the following beneficial effects:

[0027] 1. In the first reduction layer of the electrolytic cell, the organic matter in the wastewater is decomposed and removed by anodic oxidation, generating charges and protons (H+); proton hydrogen flows into the cathode area with water flow, and charges are transferred from the anode to the cathode through the external circuit; at the cathode, nitrogen and sulfur gain electrons and work together with denitrifying bacteria and desulfurizing bacteria to complete the denitrification, desulfurization and heavy metal stabilization reactions.

[0028] 2. The active components γ-Fe and α-Fe exhibit a homogeneous distribution in the bulk structure of porous biochar, which can simultaneously form numerous Fe / C and Fe / Fe15.1C dual nano-galvanic cell effects. The multi-process electrochemical corrosion reaction generates a large number of new ecological [H], and provides electrons for long-term stable reduction to remove toxic groups (such as halogenated groups) of organic matter. It can promote the bond breaking and mineralization of toxic groups (such as carboxyl COOH, azo group -N=N-), solving the problems of scaling, caking, passivation, and dead bed of traditional zero-valent iron fillers and iron-carbon fillers.

[0029] 3. In the bioreaction process of the fuel cell oxide layer, iron-rich biochar packing acts as a microbial-mediated electron shuttle. The ferrous ions released from its dissolution can rapidly consume dissolved oxygen in the environment, creating a reducing environment conducive to the survival of added microorganisms. Simultaneously, the correlation between the extracellular electron transport process of the biofilm and the surface chemical structure and interfacial properties of iron-rich biochar was systematically studied. It was found that polymorphic iron-carbon polymers (especially solid solution γ-Fe) in the bulk phase of iron-rich biochar can effectively mediate the electron transport process of the microbial extracellular respiratory chain, transferring electrons to terminal acceptor metal ions (such as Cr) or persistent organic pollutants, accelerating the reduction of Cr(VI) and the removal of toxic groups from the benzene ring. When combined with engineered microbial agents, iron-rich biochar achieves 70% removal of chlorinated aromatic hydrocarbons within 25 days, a 60% improvement in removal rate compared to traditional natural biodegradation.

[0030] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, preferred embodiments are described in detail below. Detailed Implementation

[0031] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown herein can be arranged and designed in various different configurations. Therefore, the following detailed description of the provided embodiments of the present invention is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0032] The beneficial effects of the present invention will be illustrated below through specific embodiments:

[0033] Example 1: Ecological interception and purification of a river polluted by agricultural non-point source pollution

[0034] (1) Precise construction of multi-layer functional structure

[0035] The buffer zone consists of five layers from top to bottom, with the thickness of each layer strictly controlled at 20cm.

[0036] The first reduction layer of the electrolytic cell is made of soil, steel slag and charcoal filler with a particle size of 0.10-0.30mm mixed in a weight ratio of 6:1:2, with DHC engineered bacterial agent (10^8 CFU / g) added. Reeds and cattails are planted on the surface with a plant spacing of 20cm.

[0037] Oxidation layer of electrolytic cell: 1-3mm thick Hangjin clay and sodium bentonite pad are mixed and laid in a 1:3 ratio.

[0038] The second reduction layer of the electrolytic cell is a mixture of 5-8mm steel slag and charcoal filler in a 1:6 ratio.

[0039] Fuel cell reduction layer: filled with 3-5mm aluminosilicate packing material, and a compound bacterial agent of ammonia-oxidizing anaerobic bacteria: sulfate-reducing bacteria: genomic bacillus = 2:5:3 is added.

[0040] Fuel cell oxide layer: 1-3mm gravel mixed with metal-rich biochar in a 1:8 ratio.

[0041] (2) Optimization of electrode system layout

[0042] Each functional layer is equipped with carbon fiber / polyethylene composite electrodes. The fuel cell reduction layer electrode serves as the anode, and the oxidation layer electrode serves as the cathode. They are connected to a supercapacitor (capacity 100F) via external wires to form a microbial fuel cell system with a stable output voltage of 0.61±0.05V.

[0043] (3) On-site preparation of metal-rich biochar

[0044] Siberian irises grown on the surface of a buffer zone were harvested, washed with 1 mmol / L HCl, dried at 80℃, and pulverized to 1-2 mm. The resulting Zn / Fe / Mn-loaded metal-rich biochar was prepared by pyrolysis at 900℃ for 2 hours under N2 protection with a heating rate of 10℃ / min.

[0045] Application of agricultural non-point source pollution control engineering:

[0046] An ecological buffer zone, 100m long, 8m wide, and 1m deep, will be constructed downstream of a typical agricultural watershed. Influent water quality: nitrate nitrogen 25.2mg / L, total phosphorus 1.48mg / L, atrazine 0.25mg / L, Cr(VI) 0.48mg / L.

[0047] After one year of hydrological operation, water discharge monitoring showed:

[0048] Nitrate nitrogen was reduced to 2.5 mg / L, with a removal rate of 90.1%.

[0049] Total phosphorus was reduced to 0.22 mg / L, with a removal rate of 85.1%.

[0050] Atrazine <0.01mg / L, removal rate >96%.

[0051] Cr(VI) was reduced to 0.05 mg / L, with a removal rate of 89.6%.

[0052] The system uses MFC to continuously generate electricity, achieving a power density of 85mW / m².

[0053] Example 2: Deep nitrogen and phosphorus removal of effluent from a municipal wastewater treatment plant

[0054] (1) Adaptation to high hydraulic load

[0055] The thickness of each functional layer was increased to 25cm, and the filler gradation was optimized.

[0056] A sulfur-limestone mixed packing material (1:1) was added to the first reduction layer of the electrolytic cell.

[0057] The particle size of the sand and gravel in the fuel cell oxide layer has increased to 3-5 mm.

[0058] A surface water flow distribution system is added to ensure that the hydraulic load is ≤0.5m³ / (m²·d).

[0059] (2) Enhanced combination of denitrification and phosphorus removal materials

[0060] The oxide layer is increased by 20% with lightweight sintered ceramic particles (particle size 2-4mm).

[0061] The proportion of steel slag in the second reduction layer is increased to 40%.

[0062] The fuel cell oxide layer is loaded with 5% lanthanide elements using metal-rich biochar.

[0063] (3) Landscape and ecological integration design

[0064] Top-layer plants include varieties such as Thalia dealbata and aquatic iris, which have both purification functions and ornamental value, paired with submerged plants like Vallisneria natans to form a three-dimensional configuration of trees, shrubs, and grasses.

[0065] Applications of advanced wastewater purification projects:

[0066] An 80m long and 6m wide reinforced buffer zone was constructed at the outlet of a wastewater treatment plant. The influent is secondary treated effluent with the following water quality: TN=15mg / L, TP=0.5mg / L, NH4⁺-N=8mg / L.

[0067] After 6 months of stable operation:

[0068] TN removal rate reaches 75%, effluent <5mg / L.

[0069] TP removal rate 80%, effluent <0.1mg / L.

[0070] The landscape effect is remarkable, and the plant survival rate is >95%.

[0071] Example 3: Multi-stage control of runoff pollution on a highway

[0072] (1) Runoff pretreatment system

[0073] A diversion device is installed at the front end (5mm of rainfall in the initial stage of diversion).

[0074] Intermediate sedimentation tank (HRT=30min).

[0075] End-of-pipe crushed stone energy dissipation channel (particle size 50-80mm).

[0076] (2) Design of heavy metal-specific fillers

[0077] Metal-rich biochar focuses on loading Pb and Zn adsorption sites.

[0078] The fuel cell reduction layer is increased by 10% modified zeolite.

[0079] Each layer is generally mixed with 5% magnetite to enhance the adsorption of heavy metals.

[0080] (3) Strengthening of erosion-resistant structure

[0081] The surface layer uses a grassed swale design.

[0082] Gabion revetments were installed on the slope.

[0083] The interior is reinforced with geogrid.

[0084] Applications of public path flow control engineering.

[0085] A 200m long and 5m wide runoff treatment buffer zone is constructed alongside a highway. Monitoring is conducted over one rainy season cycle.

[0086] SS removal rate is 85%, and effluent concentration is <10 mg / L.

[0087] Pb decreased from 0.15 mg / L to 0.03 mg / L.

[0088] Zn decreased from 0.35 mg / L to 0.08 mg / L.

[0089] The system withstood a rainstorm of 50 mm / h.

[0090] Example 4: Treatment and Nutrient Resource Utilization of Aquaculture Wastewater

[0091] (1) Measures to deal with high organic load

[0092] An anaerobic hydrolysis tank (HRT=24h) is set up at the front end.

[0093] The first reduction layer of the electrolytic cell contains 30% more biochar.

[0094] Plant biomass is harvested regularly (annual reed harvest of 8 kg / m²).

[0095] (2) Optimization of nitrogen and phosphorus recovery system

[0096] Anaerobic ammonia oxidizing bacteria are added to the reduction layer of the fuel cell.

[0097] Oxide layer filler loaded with magnesium-based phosphorus removal material.

[0098] Establish a synergistic recycling system for plants, fillers, and microbial agents.

[0099] (3) Precise control of operating parameters

[0100] Dissolved oxygen stratification control: surface layer >2mg / L, bottom layer <0.5mg / L.

[0101] The pH should be maintained between 6.5 and 7.5.

[0102] Water temperature should be controlled between 15-30℃.

[0103] Application in aquaculture wastewater treatment engineering.

[0104] Treatment of wastewater from a pig farm (COD=350mg / L, NH4⁺-N=65mg / L, TP=8mg / L):

[0105] COD removal rate 85%, effluent <60mg / L.

[0106] NH4⁺-N removal rate is 90%, and effluent concentration is <7 mg / L.

[0107] TP removal rate 80%, effluent <1.6mg / L.

[0108] The annual production of reed biomass is 40 tons, which can be used for feed production.

[0109] Example 5: Bypass remediation of a heavy metal-contaminated river

[0110] (1) Design of bypass water diversion system

[0111] The water diversion flow rate is controlled at 0.1-0.3 m³ / s.

[0112] Install an automatic gate control system.

[0113] Equipped with online water quality monitoring instruments.

[0114] (2) Heavy metal stabilizing materials

[0115] Each layer of packing material is mixed with 5-10% iron-rich / manganese-rich biochar.

[0116] The oxide layer of the fuel cell uses phosphate-modified biochar.

[0117] Add sulfate-reducing bacteria regularly.

[0118] (3) Ecological security monitoring system

[0119] Monitor the heavy metal content of plants monthly.

[0120] Quarterly testing of the heavy metal morphology of the packing material.

[0121] A semi-annual assessment of ecosystem integrity is conducted.

[0122] Applications in river restoration projects:

[0123] To remediate a cadmium-contaminated river (Cd=0.05mg / L, Pb=0.12mg / L).

[0124] Cd removal rate 85%, effluent <0.008mg / L.

[0125] Pb removal rate 80%, effluent <0.025mg / L.

[0126] The aquatic biodiversity index increased by 35%.

[0127] The system operates stably with no risk of secondary pollution.

[0128] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate orientations or positional relationships, or the orientations or positional relationships in which the product of this invention is conventionally placed during use. They are used only for the convenience of describing this invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention. Furthermore, the terms "first," "second," and "third," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0129] Furthermore, terms such as "horizontal," "vertical," and "sag" do not imply that components must be absolutely horizontal or suspended, but rather that they can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal relative to "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0130] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0131] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention. It should be noted that similar reference numerals and letters indicate similar items; therefore, once an item is defined, further definition and explanation are not required thereafter.

Claims

1. A method for constructing an artificial wetland ecological buffer zone, characterized in that, Artificial wetlands, from top to bottom, include: The first reduction layer of the electrolytic cell includes an electrolytic cathode; the first reduction layer of the electrolytic cell is filled with soil, steel slag and charcoal filler; DHC engineered bacteria agent is added to the first reduction layer of the electrolytic cell, and plants are also planted on the surface; The electrolytic cell oxide layer includes an electrolytic anode; the electrolytic cell oxide layer is filled with Hangjin clay and sodium-based bentonite pads; The second reduction layer of the electrolytic cell includes an electrolytic cathode; the second reduction layer of the electrolytic cell is filled with steel slag and charcoal filler. The fuel cell reduction layer is filled with aluminosilicate filler; engineered microbial agents are also added to the fuel cell reduction layer. The fuel cell oxide layer is filled with gravel and metal-rich biochar.

2. The method for constructing an artificial wetland ecological buffer zone according to claim 1, characterized in that, The thickness of the first reduction layer, the oxide layer, the second reduction layer, the reduction layer, and the oxide layer of the fuel cell are all 20 cm. Plastic electrodes are respectively arranged in the first reduction layer, the oxidation layer, the second reduction layer, the fuel cell reduction layer, and the fuel cell oxidation layer of the electrolytic cell. The electrodes in the fuel cell reduction layer and the fuel cell oxidation layer are connected by wires and capacitors, and power is supplied to the first reduction layer, the oxidation layer, and the second reduction layer of the electrolytic cell.

3. The method for constructing an artificial wetland ecological buffer zone according to claim 2, characterized in that, In the first reduction layer of the electrolytic cell, the particle size of the soil, steel slag and charcoal filler is 0.10-0.30 mm, and the mixing ratio is 5:1:4-8:1:

1.

4. The method for constructing an artificial wetland ecological buffer zone according to claim 2, characterized in that, In the oxide layer of the electrolytic cell, the particle size of the Hangjin clay and the sodium-based bentonite pad is 1-3 mm, and the mixing ratio is 1:2-1:

5.

5. The method for constructing an artificial wetland ecological buffer zone according to claim 2, characterized in that, In the second reduction layer of the electrolytic cell, the particle size of the steel slag and charcoal filler is 5-8 mm, and the mixing ratio is 1:4-1:

10.

6. The method for constructing an artificial wetland ecological buffer zone according to claim 2, characterized in that, In the fuel cell reduction layer, the particle size of the aluminosilicate filler is 3-5 mm.

7. The method for constructing an artificial wetland ecological buffer zone according to claim 2, characterized in that, In the oxidation layer of the fuel cell, the gravel and metal-rich biochar have a particle size of 1-3 mm and a mixing ratio of 1:5-1:

10.

8. The method for constructing an artificial wetland ecological buffer zone according to claim 2, characterized in that, The metal-rich biochar is prepared by the following method: Siberian iris plants were planted in a solution of zinc chloride supplemented with one or more of copper chloride, cerium chloride, ferric chloride, and manganese chloride. After two months of cultivation, they were harvested, dried, and crushed. After calcination, biochar loaded with monatomic or coordinated metals was obtained.

9. The method for constructing an artificial wetland ecological buffer zone according to claim 2, characterized in that, In the fuel cell reduction layer, the engineered bacterial agents are ammonia-oxidizing anaerobic bacteria, sulfate-reducing bacteria and Geothermal bacteria, with a mixing ratio of 2:5:

3.

10. An artificial wetland ecological buffer zone device, characterized in that, It is constructed using the construction method of an artificial wetland ecological buffer zone as described in any one of claims 1-9.