Modularized subsurface flow denitrification water source ecological wetland system

Abstract

The modularized subsurface flow denitrification water source ecological wetland system comprises a water distribution channel and a water collection channel, the water distribution channel and the water collection channel are connected through a base, an impermeable layer is installed on the upper surface of the base, and a net-shaped frame body is fixedly installed at the top end of the impermeable layer; the interior of the net-shaped frame body is divided into different units through a plurality of groups of high partition plates and low partition plates, and the units comprise a first filler unit, a second filler unit, a carbon source filling unit, a third filler unit, a movable carbon unit and a fourth filler unit. The modularized filling units can be supplemented and replaced in time when a carbon source loses efficacy and filler is blocked, long-term operation of the wetland can be effectively guaranteed, the wetland units can be flexibly arranged according to the overall design of a wetland area and the effluent quality requirement, the wetland wall plates are adopted to form the pool wall of the wetland pool body, and the wetland pool body is convenient to use. The assembly time of the modular wetland can be shortened, and the engineering construction cost is reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of ecological environment protection, in particular to a modular subsurface denitrification water source ecological wetland system. Background Art

[0002] Nitrate pollution in surface water is a serious aquatic environmental issue facing China. Large amounts of polluted water discharged from industrial production and excessive fertilizer use in agricultural activities have led to elevated nitrate levels in surface water, damaging the aquatic ecosystem and causing ecosystem degradation, impacting the safety of drinking water. Safe, efficient, and economical nitrate removal from surface water is crucial for ensuring drinking water safety and improving the quality of the aquatic ecosystem.

[0003] As a typical ecological treatment technology, artificial wetlands mainly utilize the synergistic effect between substrates, microorganisms and plants.

[0004] The removal of pollutants from water bodies can effectively and reliably purify water bodies while beautifying the environment. However, when artificial wetlands treat surface water with a low carbon-nitrogen ratio and high nitrate, their denitrification effect is limited by the key factor of carbon source, and an external carbon source is needed to improve the denitrification effect of the wetland. The types of external carbon sources for traditional artificial wetlands mainly include low-molecular organic carbon sources, sugar substances and biodegradable multi-molecular polymers, but these products have high market prices and are easy to affect the water quality of the effluent. In addition, the method of adding carbon sources is also an important factor affecting the denitrification efficiency of wetlands. Traditional artificial wetlands usually add carbon sources to the interior of the wetland structure, which results in the inability to replenish and replace the carbon source in time after it fails, which is prone to clogging, limiting the denitrification effect of artificial wetlands.

[0005] Therefore, in order to protect the water quality safety of surface water sources, based on the current technical status of artificial wetlands in treating surface water with low carbon-nitrogen ratio and high nitrate, it is necessary to design a new type of artificial wetland structure. While ensuring the nitrate removal effect, it is convenient to supplement and replace the carbon source and easy to operate and manage. Therefore, a modular subsurface denitrification water source ecological wetland system is now needed. Utility Model Content

[0006] The purpose of the present invention is to provide a modular subsurface denitrification water source ecological wetland system, which satisfies the protection of artificial wetlands through a multi-unit water filtration and treatment structure, so as to solve the problems raised in the above background technology.

[0007] To achieve the above objectives, the present invention provides the following technical solutions: a modular subsurface denitrification water source ecological wetland system, comprising a water distribution channel and a water collection channel, wherein the water distribution channel and the water collection channel are connected via a base, an impermeable layer is installed on the upper surface of the base, and a mesh frame is fixedly installed on the top of the impermeable layer;

[0008] The interior of the mesh frame is divided into different units by a plurality of groups of high partitions and low partitions, wherein the units include a first filler unit, a second filler unit, a carbon source filling unit, a third filler unit, an active carbon unit and a fourth filler unit;

[0009] A group of reinforcement and anti-permeability structures are respectively installed inside the first filler unit, the second filler unit, the third filler unit and the fourth filler unit. A modular wetland unit is placed inside each group of reinforcement and anti-permeability structures, and the modular wetland unit is filled with modular fillers.

[0010] Preferably, two groups of water exchange ports are symmetrically opened on the upper part of the anti-seepage layer on the corresponding sides of the water distribution channel and the water collection channel, and the top of the water distribution channel and the water collection channel are respectively covered with a group of covers to prevent evaporation.

[0011] Preferably, the substrate is one of a group consisting of a PVC board, a wooden board or a stainless steel board, and the anti-seepage layer is one of a group consisting of a HDPE anti-seepage membrane, a geomembrane, a PVC anti-seepage membrane or a clay layer.

[0012] Preferably, a water exchange trough is provided at the lower portion of the high partition, and the upper surfaces of the first filler unit, the second filler unit, the third filler unit and the fourth filler unit are covered with a porous adsorption filter screen, and a planting hole is provided through the center of the porous adsorption filter screen.

[0013] Preferably, an AC window is provided on one side of the reinforcement and anti-permeation structure corresponding to the water exchange tank position, and a porous material adsorption filter box is installed inside the AC window. A baffle is provided at one end of the porous material adsorption filter box, and the baffle is installed by being snapped into the inner wall of the reinforcement and anti-permeation structure.

[0014] Preferably, the volume ratio of the first filler unit, the second filler unit, the carbon source filler unit, the third filler unit, the active carbon unit, and the fourth filler unit is 3:3:(1-3):3:(1-3):3, and the residence time is set according to 0.8-2.5d. The module filler is filled with one or more of zeolite, gravel, volcanic rock, and expanded clay. The filler particle size of the first filler unit is 10-30mm, the filler particle size of the second filler unit is 2-6mm, the filler particle size of the third filler unit is 5-10mm, and the filler particle size of the fourth filler unit is 10-30mm.

[0015] Preferably, the active carbon unit is made of granular activated carbon with a particle size of 3 to 10 mm, and the carbon source filling unit is made of acid-treated corn straw with a length of 1 to 4 cm and a width of 1 to 3 cm.

[0016] Compared with the prior art, the beneficial effects of the present invention are:

[0017] The modular filling units in the utility model can be replenished and replaced in time when the carbon source fails or the filler is clogged, which can effectively ensure the long-term operation of the wetland. In addition, the wetland units can be flexibly arranged according to the overall design of the wetland area and the water quality requirements of the effluent.

[0018] The utility model strengthens the nitrification and denitrification processes in the wetland system by adding corn straw as a carbon source, thereby improving its denitrification efficiency and maintaining a stable environment within the wetland system; corn straw as an external carbon source can effectively reduce operating costs and remove nitrates from surface water sources in a green and efficient manner.

[0019] The utility model adopts wetland wall panels to form the pool wall of the wetland pool body, which can speed up the assembly time of the modular wetland and reduce the construction cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a schematic diagram of the structure of the utility model;

[0021] Figure 2 This is a schematic diagram of the installation structure of the mesh frame of the utility model;

[0022] Figure 3 This is a disassembled diagram of the installation structure of the modular wetland unit of the utility model.

[0023] In the figure: 1. Water distribution channel; 2. Water collection channel; 3. Base; 4. Anti-seepage layer; 5. Mesh frame; 6. High partition; 7. Low partition; 8. First filler unit; 9. Second filler unit; 10. Carbon source filling unit; 11. Third filler unit; 12. Active carbon unit; 13. Fourth filler unit; 14. Water exchange tank; 15. Porous adsorption filter; 16. Anti-evaporation cover; 17. Reinforcement and anti-seepage structure; 18. Exchange window; 19. Porous material adsorption filter box; 20. Modular wetland unit; 21. Modular filler; 22. Wetland plants. DETAILED DESCRIPTION

[0024] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0025] The utility model provides: a modular subsurface denitrification water source ecological wetland system, such as Figure 1-Figure 3As shown, it includes a water distribution channel 1 and a water collection channel 2, which are connected by a base 3. An anti-seepage layer 4 is installed on the upper surface of the base 3, and a mesh frame 5 is fixedly installed on the top of the anti-seepage layer 4; the interior of the mesh frame 5 is divided into different units by several groups of high partitions 6 and low partitions 7, and the units include a first filler unit 8, a second filler unit 9, a carbon source filling unit 10, a third filler unit 11, an active carbon unit 12 and a fourth filler unit 13; a group of reinforcement and anti-seepage structures 17 are respectively installed inside the first filler unit 8, the second filler unit 9, the third filler unit 11 and the fourth filler unit 13, each of which has a modular wetland unit 20 placed inside. The modular wetland unit 20 is filled with modular fillers 21;

[0026] The first filler unit 8 is filled with one or more of zeolite, gravel, volcanic rock, and ceramsite with a diameter of 10 to 30 mm;

[0027] The second filler unit 9 is filled with one or more of zeolite, gravel, volcanic rock, and ceramsite with a diameter of 2 to 6 mm;

[0028] The corn straw in the carbon source filling unit 10 can absorb a large number of nitrifying bacteria, denitrifying bacteria and other mixed bacteria. The ammonia nitrogen in the water is oxidized to nitrate by the nitrifying bacteria adsorbed on the corn straw. The nitrate is then denitrified and reduced by the denitrifying bacteria using the straw as a carbon source.

[0029] The third filler unit 11 is filled with one or more of zeolite, gravel, volcanic rock, and ceramsite with a diameter of 5 to 10 mm, which can intercept small corn stalks flowing out with the water;

[0030] The granular activated carbon in the activated carbon unit 12 can control the chromaticity and organic matter content of the effluent while maintaining the pH stability of the system. The activated carbon unit is filled with granular activated carbon with a particle size of 3 to 10 mm.

[0031] The fourth filler unit 13 is filled with one or more of zeolite, gravel, volcanic rock, and ceramsite with a size of 10 to 30 mm.

[0032] Preferably, two groups of water exchange ports are symmetrically opened on the corresponding sides of the water distribution channel 1 and the water collection channel 2 on the upper part of the anti-seepage layer 4, and the top of the water distribution channel 1 and the water collection channel 2 are respectively covered with a group of evaporation prevention covers 16. The water exchange ports opened on the upper part of the water distribution channel 1 and the water collection channel 2 can ensure the natural outflow and inflow of water, so that the water can flow out through the water distribution channel 1 and then be filtered through the mesh frame 5, and the filtered water can enter the water collection channel 2. At the same time, the evaporation cover 16 installed on the top of the water distribution channel 1 and the water collection channel 2 can effectively prevent external dust from entering and causing secondary pollution to the water body, and can also avoid the waste of water resources caused by water evaporation. The water body inside the water distribution channel 1 is surface water with a low carbon-nitrogen ratio and high nitrate, such as reservoir water, river water, etc.

[0033] Furthermore, the base 3 is one of the groups of PVC board, wooden board or stainless steel board, and the anti-seepage layer 4 is one of the groups of HDPE anti-seepage membrane, geomembrane, PVC anti-seepage membrane or clay layer. The base 3 and the anti-seepage layer 4 can cooperate to protect the mesh frame 5, and the wetland water body is filtered through the cooperation of the mesh frame 5 and the first filler unit 8, the second filler unit 9, the carbon source filling unit 10, the third filler unit 11, the active carbon unit 12 and the fourth filler unit 13.

[0034] Furthermore, a water exchange trough 14 is provided at the lower part of the high partition 6, and the upper surfaces of the first filler unit 8, the second filler unit 9, the third filler unit 11 and the fourth filler unit 13 are covered with a porous adsorption filter 15. A planting hole is provided through the center of the porous adsorption filter 15. The high partition 6 and the low partition 7 arranged inside the mesh frame 5 enable the water to seep out alternately from the top and bottom to complete multiple filtration, thereby improving the purification effect of the water.

[0035] It is worth mentioning that an exchange window 18 is provided on one side of the reinforcement and anti-seepage structure 17 at the position corresponding to the water exchange tank 14. A porous material adsorption filter box 19 is installed inside the exchange window 18. A baffle is provided at one end of the porous material adsorption filter box 19, and the baffle is installed in the inner wall of the reinforcement and anti-seepage structure 17. The exchange window 18 and the embedded porous material adsorption filter box 19 in the reinforcement and anti-seepage structure 17 purify the downstream water body, and the porous adsorption filter screen 15 is used to filter the upper water body, further enhancing the purification purpose of the wetland.

[0036] Specifically, the volume ratio of the first filler unit 8, the second filler unit 9, the carbon source filling unit 10, the third filler unit 11, the active carbon unit 12, and the fourth filler unit 13 is 3:3:(1-3):3:(1-3):3, and the residence time is set according to 0.8-2.5d. By limiting the proportion of each module and controlling the time for water to enter each module, the overall device can ensure the removal of nitrates in the water and improve the water quality.

[0037] The water in the water distribution channel is surface water with a low carbon-to-nitrogen ratio and high nitrate content, such as reservoir water or river water. The first packing unit 3 is located on the left side of the system. Water overflowing from the water distribution channel 1 enters the upper portion of the first packing unit 3. After being treated by the packing within the unit, it enters the second packing unit 6 through the bottom hole of the wetland wall on the right side of the unit. The first packing unit 3 is filled with one or more of 10-30 mm zeolite, gravel, volcanic rock, and ceramsite.

[0038] In the modular subsurface denitrification water source ecological wetland device of this embodiment, the surface water source water denitrification experiment is carried out:

[0039] The module filler 21 is filled with one or more of zeolite, gravel, volcanic rock, and expanded clay. The filler particle size of the first filler unit 8 is 10 to 30 mm, the filler particle size of the second filler unit 9 is 2 to 6 mm, the filler particle size of the third filler unit 11 is 5 to 10 mm, and the filler particle size of the fourth filler unit 13 is 10 to 30 mm. The active carbon unit 12 uses granular activated carbon with a particle size of 3 to 10 mm, and the carbon source filling unit uses acid-treated corn straw with a length of 1 to 4 cm and a width of 1 to 3 cm.

[0040] Water enters from the bottom of the second filler unit 6, and after being processed by the filler in the unit, overflows into the carbon source filling unit 8. The second filler unit 6 is filled with one or more of 2-6 mm zeolite, gravel, volcanic rock, and ceramsite.

[0041] Water enters the carbon source filling unit 8 from the top. The corn stalks within the unit attract a large number of nitrifying and denitrifying bacteria. Nitrifying bacteria adsorbed on the corn stalks oxidize ammonia nitrogen in the water to nitrate. Denitrifying bacteria then use the stalks as a carbon source for denitrification. A preferred carbon source filling layer is acid-treated corn stalks 1 to 4 cm long and 1 to 3 cm wide.

[0042] The water enters the bottom of the third filler unit 10 through the hole at the bottom of the wetland wall on the right side of the carbon source filling unit 8. The third filler unit 10 is filled with one or more of 5-10 mm zeolite, gravel, volcanic rock, and ceramsite, which can intercept the small corn stalks flowing out with the water.

[0043] Water overflows from the top of the third filler unit 10 and enters the activated carbon unit 11. The granular activated carbon in the activated carbon unit 11 controls the chromaticity and organic content of the effluent while maintaining a stable pH value. As a preferred option, the activated carbon unit is filled with granular activated carbon with a particle size of 3 to 10 mm.

[0044] The volume ratio of the activated carbon unit 11 to the carbon source filling unit 8 is (1-3): (1-3). The water body removes most of the nitrate in the influent water in the carbon source filling unit and the activated carbon unit (the nitrate removal rate is above 85%).

[0045] The water enters the fourth filler unit 12 from the hole at the bottom of the wetland wall panel on the right side of the activated carbon unit 11. The fourth filler unit 12 is filled with one or more of zeolite, gravel, volcanic rock, and ceramsite with a diameter of 10 to 30 mm.

[0046] Water enters from the bottom of the fourth filler unit 12, and after being processed by the filler in the unit, overflows from the top and enters the water collection channel, completing the water purification process.

[0047] The wetland plants planted on the upper part of the filler unit are one or a combination of cattail, calamus, reed, etc., with a planting density of 9 to 25 plants per square meter.

[0048] The fillers in the wetland modular filler units can remove some inorganic nitrogen and provide support for the growth of microorganisms and plants. Planting wetland plants in the filler units can promote denitrification of water bodies. Microorganisms use the oxygen secreted by plant roots to oxidize ammonia nitrogen in the water into nitrate through nitrification reaction. The nitrate in the water body is reduced to nitrogen gas by denitrifying bacteria using organic matter secreted by the roots as electron donors.

[0049] The utility model modularizes the various units of the wetland, so that they can be replenished and replaced in time when the carbon source fails or the filler is clogged; the use of pretreated corn straw as an external carbon source for the wetland can effectively improve the availability of plant carbon sources, enhance the denitrification effect of the system, and realize a green and efficient denitrification mode for the wetland system.

[0050] The preparation process of the carbon source filling unit 10 includes the following steps:

[0051] Pretreatment of corn straw: First, cut the corn straw into straw segments with a length of 1 to 4 cm and a width of 1 to 3 cm, soak them in 1% sulfuric acid solution for 18 hours, wash the surface with distilled water several times until the pH is about 7, and dry them in a 60°C oven for 8 hours.

[0052] In the embodiment, a first filler unit 8, a second filler unit 9, a carbon source filling unit 10, a third filler unit 11, an activated carbon unit 12, and a fourth filler unit 13 are arranged from left to right in a volume ratio of 3:3:1:3:1:3. The experimental hydraulic retention time is 1d. During the experiment, the influent nitrate concentration is 11.45±2.06mg / L; the total nitrogen concentration is 12.54±1.68mg / L, and the COD concentration is 3.83±0.87mg / L. After 30 days of experiment, the effluent nitrate nitrogen concentration is 1.22mg / L~1.84mg / L, and the average removal rate can reach 90%; the total nitrogen concentration is 2.58mg / L~3.83mg / L, and the average removal rate can reach 74%. The COD concentration in the effluent is 3.67~4.14mg / L, which meets the COD concentration requirements of Class I water specified in the "Surface Water Environmental Quality Standard" (GB3838-2002).

[0053] This utility model uses overflow from a water distribution channel 1 to enter a first packing unit 8, where the packing, combined with wetland plants, removes some nitrogen pollution from the water. Nitrifying and denitrifying bacteria in a carbon source packing unit 10 utilize straw as a carbon source to complete a nitrification-heterotrophic denitrification process, significantly removing nitrates from the water. An activated carbon unit 12 ensures that the effluent's color and organic matter content meet standards. This modular system utilizes corn straw combined with activated carbon to achieve deep denitrification of surface water with a low C / N ratio, primarily nitrates and containing some dissolved oxygen.

[0054] The modularization of each unit of the wetland makes it easy to remove and replace the carbon source unit and the module unit of the blocked part when the carbon source fails or the filler is blocked, and it is convenient for on-site construction and installation; the use of acid-treated corn straw as an external carbon source can effectively improve the availability of plant carbon sources and enhance the denitrification effect of the wetland system; the activated carbon matrix has the advantages of large specific surface area, developed pore structure and rich micropores, which can efficiently adsorb organic matter in the water, control the chromaticity of the effluent, and maintain the pH stability of the wetland system. The modular subsurface denitrification water source ecological wetland modularizes each unit of the wetland, efficiently combines fillers, corn straw and activated carbon materials, and realizes a green and efficient denitrification model that combines autotrophic and heterotrophic denitrification in the modular wetland system.

[0055] Although the embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations may be made to these embodiments without departing from the principles and spirit of the present invention, and the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A modular subsurface denitrification water source ecological wetland system, characterized by: It comprises a water distribution channel (1) and a water collection channel (2), wherein the water distribution channel (1) and the water collection channel (2) are connected via a base (3), an anti-seepage layer (4) is installed on the upper surface of the base (3), and a mesh frame (5) is fixedly installed on the top of the anti-seepage layer (4); The interior of the mesh frame (5) is divided into different units by a plurality of groups of high partitions (6) and low partitions (7), wherein the units include a first filler unit (8), a second filler unit (9), a carbon source filler unit (10), a third filler unit (11), an active carbon unit (12) and a fourth filler unit (13); A group of reinforcement and anti-permeability structures (17) are respectively installed inside the first filler unit (8), the second filler unit (9), the third filler unit (11), and the fourth filler unit (13), and a modular wetland unit (20) is placed inside each group of the reinforcement and anti-permeability structures (17), and the modular wetland unit (20) is filled with modular fillers (21).

2. A modular subsurface denitrification water source ecological wetland system according to claim 1, characterized in that: Two groups of water exchange ports are symmetrically opened on the upper part of the anti-seepage layer (4) on the corresponding sides of the water distribution channel (1) and the water collection channel (2). The tops of the water distribution channel (1) and the water collection channel (2) are respectively covered with a group of evaporation prevention covers (16).

3. A modular subsurface denitrification water source ecological wetland system according to claim 2, characterized in that: The base (3) is one of a PVC board, a wooden board or a stainless steel board, and the anti-seepage layer (4) is one of a HDPE anti-seepage membrane, a geomembrane, a PVC anti-seepage membrane or a clay layer.

4. A modular subsurface denitrification water source ecological wetland system according to claim 3, characterized in that: A water exchange trough (14) is provided at the lower portion of the high partition (6), and the upper surfaces of the first filler unit (8), the second filler unit (9), the third filler unit (11), and the fourth filler unit (13) are covered with a porous adsorption filter (15), with a planting hole being provided through the center of the porous adsorption filter (15).

5. A modular subsurface denitrification water source ecological wetland system according to claim 4, characterized in that: An exchange window (18) is provided on one side of the reinforcement and anti-permeation structure (17) at a position corresponding to the water exchange tank (14), and a porous material adsorption filter box (19) is mounted inside the exchange window (18). A baffle is provided at one end of the porous material adsorption filter box (19), and the baffle is mounted on the inner wall of the reinforcement and anti-permeation structure (17).

6. A modular subsurface denitrification water source ecological wetland system according to claim 5, characterized in that: The volume ratio of the first filler unit (8), the second filler unit (9), the carbon source filler unit (10), the third filler unit (11), the active carbon unit (12), and the fourth filler unit (13) is 3:3:(1-3):3:(1-3):3, and the residence time is set according to 0.8-2.5 days. The modular filler (21) is filled with one or more of zeolite, gravel, volcanic rock, and ceramsite. The filler particle size of the first filler unit (8) is 10-30 mm, the filler particle size of the second filler unit (9) is 2-6 mm, the filler particle size of the third filler unit (11) is 5-10 mm, and the filler particle size of the fourth filler unit (13) is 10-30 mm.

7. A modular subsurface denitrification water source ecological wetland system according to claim 6, characterized in that: The active carbon unit (12) uses granular activated carbon with a particle size of 3 to 10 mm, and the carbon source filling unit uses acid-treated corn straw with a length of 1 to 4 cm and a width of 1 to 3 cm.

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