Nitrous oxide emission reduction device for sulfur autotrophic filter material constructed wetland

Abstract

The utility model discloses a nitrous oxide emission reduction device for a sulfur autotrophic filter material constructed wetland, which is characterized in that the constructed wetland is sequentially provided with a soil layer, a sulfur autotrophic filter material layer C1a, a zeolite filler layer C2, a sulfur autotrophic filter material layer C1b and a gravel supporting layer from top to bottom, the aeration unit comprises a microporous aeration pipe arranged at the bottom of the device; a water inlet / outlet at the bottom and a water inlet / outlet at the top are connected with a water collecting tank for controlling the water inlet / outlet of the wetland unit; water flow of the constructed wetland is upward flow, and emergent aquatic plants are arranged on the soil layer. According to the invention, the filler type of the constructed wetland is changed, the filling quality of the sulfur autotrophic filter material is flexibly adjusted according to actual requirements, the pollutant treatment efficiency of the constructed wetland and the emission flux of greenhouse gas N2O are regulated and controlled, and water purification cooperates with greenhouse emission reduction; the method can be applied to domestic sewage treatment in rural areas or small-range cities and towns, tail water purification of sewage treatment plants and ecological protection of rivers and lakes.

Description

Technical Field

[0001] The utility model belongs to the field of sewage denitrification treatment, greenhouse emission reduction and artificial wetland, and specifically relates to a sulfur autotrophic filter material artificial wetland nitrous oxide emission reduction device. Background Art

[0002] As a comprehensive and multifunctional ecosystem, artificial wetlands play an important role in sewage treatment and are widely used in polluted water treatment and river and lake management. However, the operation of traditional artificial wetlands will produce certain greenhouse gases, which greatly reduces their environmental benefits. Studies have shown that the release flux of greenhouse gases in artificial wetlands is 2 to 10 times that of natural wetlands.

[0003] N2O is an important member of greenhouse gases. N2O is a byproduct of nitrification and an intermediate product of denitrification. Traditional artificial wetlands usually lack bioavailable carbon sources, which inhibits the complete denitrification process and ultimately leads to the release of a large amount of N2O. Achieving complete heterotrophic denitrification and promoting the occurrence of autotrophic denitrification are important ways to reduce the production of N2O in wetlands.

[0004] Wetland fillers are the skeleton of artificial wetlands, providing a place for microorganisms to grow and reproduce. The physical and chemical properties of wetland fillers often affect the water content, microbial population, enzyme activity, pH value, organic matter content, etc. in the system, which in turn affects the release of greenhouse gases. Studies have shown that fillers with high water retention, such as soil and fine sand, will limit the transmission of O2 into the system, leading to an anaerobic environment, thereby increasing the release of N2O. Therefore, by studying artificial wetland fillers, greenhouse gas emissions from artificial wetlands can be effectively reduced. Utility Model Content

[0005] Purpose of the utility model: In order to overcome the problems of low pollutant removal efficiency and high greenhouse gas emissions of traditional artificial wetlands in the sewage treatment process, the utility model provides a sulfur autotrophic filter material artificial wetland N2O emission reduction device and method, which can reduce greenhouse gas emissions caused by artificial wetlands by flexibly adjusting the type of sulfur autotrophic filter material and the height of the filling matrix without affecting the pollutant removal efficiency of the artificial wetland.

[0006] The utility model can promote the further conversion of N2O and reduce the release of N2O according to the characteristics of the autotrophic denitrification process driven by thiosulfate, use inorganic sulfur autotrophic filler instead of traditional organic matter as electron donor, improve the decontamination level of artificial wetland, and reduce the greenhouse contribution potential.

[0007] To achieve the above purpose, the utility model provides a sulfur autotrophic filter material artificial wetland nitrous oxide emission reduction device, the artificial wetland is provided with a soil layer, a sulfur autotrophic filter material layer C from top to bottom in sequence. 1a, zeolite filler layer C2, sulfur autotrophic filter layer C 1b , gravel support layer, of which:

[0008] An aeration unit is provided at the bottom of the artificial wetland, and the aeration unit includes a microporous aeration pipe provided at the bottom of the device;

[0009] The upper part of the artificial wetland is provided with a gas collecting unit.

[0010] The water inlet and outlet at the bottom and top of the artificial wetland are connected to a water collection tank for controlling the water inlet and outlet of the wetland unit;

[0011] The water flow of the artificial wetland is an upward flow, and emergent plants are arranged in the soil layer.

[0012] Specifically, the microporous aeration tube is arranged 5-6 cm away from the bottom of the device, and is connected to the air compressor through an aeration conduit. A flow meter and a timing switch are arranged between the air compressor and the microporous aeration tube to control the aeration amount and aeration time.

[0013] The gas collection unit comprises a water seal groove arranged on the upper part of the artificial wetland, the water seal groove is provided with a static gas sampling box, and the middle part of the static gas sampling box is provided with two gas openings.

[0014] The soil in the soil layer is selected from any one or more of brick red soil, red soil, red soil, and brown soil, and the filling thickness is 5-10 cm.

[0015] The sulfur autotrophic filter material layer C 1a , C 1b It is sulfur autotrophic filler or other self-made sulfur filler, with a filling range of 15-30cm;

[0016] The zeolite filler layer C2 is natural clinoptilolite with a particle size of 5 to 10 mm, a porosity of 47%, and a filling thickness range of 10 to 30 cm;

[0017] The sulfur autotrophic filter material layer C 1a , C 1b The total height of the zeolite packing layer C2 is h 总 =h C1 +h C2 +h C3 =40~90cm, where h C1 =h C3 =0.5*(h 总 -h C2 )cm;

[0018] The gravel support layer is common bluestone for construction, with a particle size of 1 to 3 cm, a porosity of 53.00%, and a filling thickness range of 5 to 10 cm;

[0019] The upper part of the zeolite filler layer C2 is a sulfur autotrophic filter material layer C 1a , below is the sulfur autotrophic filter layer C 1b The sulfur autotrophic filter material layer is sandwiched between the upper and lower parts of the zeolite filler layer C2, which is conducive to the sewage fully contacting the matrix, improving the pollutant removal efficiency, reducing the emission of N2O gas, and extending the operation period of the artificial wetland.

[0020] Among them, the calculation formula for the mass of sulfur autotrophic filter material required in the artificial wetland is as follows:

[0021] G=ρ*(π*d 2 / 4)*h

[0022] G----Total mass of sulfur autotrophic filter material required for artificial wetlands, unit (t);

[0023] ρ----density of sulfur autotrophic filter material, can be 1.2, unit (t·m -3 );

[0024] d----Inner diameter of artificial wetland, unit (m);

[0025] h----the height of the sulfur autotrophic filter material filled in the artificial wetland, unit (m);

[0026] The calculation formula of N2O gas emission flux in the artificial wetland of the present invention is as follows:

[0027] F1=α*F0*h0 / h1

[0028] F----N2O gas emission flux in artificial wetland, unit (mg·m -2 ·h -1 );

[0029] α----N2O gas emission coefficient in artificial wetlands, taken as 0.95;

[0030] F0: the maximum flux of N2O gas emission in the artificial wetland of the present invention, taken as 0.25, unit (mg·m -2 ·h -1 );

[0031] h0----the filling height of the sulfur autotrophic filter material corresponding to the maximum flux of N2O gas emission in the artificial wetland of the present invention, taken as 0.05, unit (m);

[0032] h1----the filling height of the sulfur autotrophic filter material corresponding to the N2O gas emission in the artificial wetland of the present invention is F1, unit (m);

[0033] In one embodiment, the emergent plant is Iris pumila, and the planting density is 2 to 3 plants per system.

[0034] An axial flow fan is arranged on the top of the static gas sampling box to mix the air in the box.

[0035] A device supporting layer is arranged at the bottom of the device for supporting the whole device.

[0036] The operation mode of the above-mentioned sulfur autotrophic filter material artificial wetland is as follows:

[0037] (1) The water inlet at the bottom of the artificial wetland is connected to the water collection tank, and the water inlet to the wetland is controlled by the water inlet valve;

[0038] (2) Aerating polluted water to increase dissolved oxygen concentration;

[0039] (3) The aerated water is pumped upward through the packing layer by a peristaltic pump, and the treated water flows out from the upper outlet and returns to the water collection tank. The wetland water inlet method is continuous water inlet, and the hydraulic load is 0.10m / d;

[0040] (4) Collect N2O from the static gas collection port.

[0041] Beneficial effects: Compared with the prior art, the utility model has the following advantages:

[0042] (1) The present invention applies sulfur autotrophic filter material to artificial wetlands without adding additional carbon sources, thus overcoming the bottleneck of traditional artificial wetlands requiring external carbon sources to provide electron donors, having significant carbon reduction benefits, and reducing the emission of greenhouse gas N2O, thereby achieving dual carbon reduction;

[0043] (2) The combination of artificial wetlands and sulfur autotrophic denitrification forms mixed denitrification within the wetland system, which significantly reduces the production of sulfate and reduces the potential risk of sulfur pollution. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 It is a plan view of the artificial wetland system of the utility model;

[0045] Among them: 1. Air compressor; 2. Aeration duct; 3. Microporous aeration tube; 4. Device support layer; 5. Gravel support layer; 6. Sulfur autotrophic filter layer C 1a ; 7. Zeolite filler layer C2; 8. Sulfur autotrophic filter material layer C 1b ; 9. Soil layer; 10. Iris; 11. Gas collection port; 12. Axial flow fan; 13. Peristaltic pump; 14. Artificial wetland inlet regulating valve; 15. Artificial wetland outlet regulating valve; 16. Water collecting tank inlet; 17 Water collecting tank; 18. Water collecting tank outlet.

[0046] Figure 2 The figure is a schematic diagram of the operation principle of the artificial wetland system described in the utility model. DETAILED DESCRIPTION

[0047] In order to make the purpose, technical solution and beneficial effects of the utility model more clear, the utility model is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the utility model and are not used to limit the utility model.

[0048] For ease of description, spatially relative terms, such as "under", "below", "down", "above", "upper", etc., will be used when necessary to describe the relationship of one element or feature relative to another element or feature shown in the drawings. The spatially relative terms are intended to include different orientations of the device in use or operation other than the orientation shown in the drawings. For example, if the device in the figure is turned over, elements described as being "under" or "beneath" other elements or features will be oriented as being "above" the other elements or features.

[0049] Unless otherwise defined, the terms used herein have the same meaning as commonly understood by ordinary technicians in the field to which the present invention belongs, and the terms should be understood to have the same meaning as in the context of the relevant technology and should not be understood in an idealized or overly formal way, except for the cases explicitly defined in the present invention.

[0050] Example 1

[0051] like Figure 1 and Figure 2 As shown, this embodiment proposes a sulfur autotrophic filter material artificial wetland N2O emission reduction device, the artificial wetland is provided with a soil layer, a sulfur autotrophic filter material layer C from top to bottom in sequence. 1a , zeolite filler layer C2, sulfur autotrophic filter layer C 1b , gravel support layer. The emission reduction device specifically includes an aeration unit, a microporous aeration pipe 2 is set 5 cm from the bottom of the sulfur autotrophic filter material artificial wetland N2O emission reduction device, an air compressor 1 is used for aeration, and a flow meter is used to control the aeration volume, and a timer switch is used to control the aeration time; a gas collection unit, a water seal tank is set on the upper part of the artificial wetland system, and a matching static gas sampling box is placed, and two gas openings 11 are set in the middle of the gas sampling box; a water collection unit, the bottom and top water inlet and outlet of the artificial wetland are connected to a water collection box 17, which can control the water inlet and outlet of the wetland unit.

[0052] The water flow of the artificial wetland is an upward flow. The peristaltic pump 13 delivers water to the bottom of the device. The middle of the device is filled with fillers. The upper surface is planted with the emergent plant Iris calamus 10, with a planting density of 2 plants / system. An axial fan 12 is installed in the static gas sampling box of the gas collection unit to mix the air in the box. The aeration unit adopts intermittent aeration, aeration for 2 hours a day, that is, aeration is carried out from 00:00 to 01:00 and 12:00 to 13:00 every day, and the DO in the aeration section is controlled at 3 mg·L -1The COD, ammonia nitrogen and total phosphorus concentrations of the simulated sewage influent of the water collection unit are 400 mg / L, 40 mg / L and 10 mg / L respectively.

[0053] The artificial wetland is set up from top to bottom in the soil layer, sulfur autotrophic filter layer C 1a , zeolite filler layer C2, sulfur autotrophic filter layer C 1b , gravel support layer; soil layer soil is selected from brick red soil, filling thickness is 10cm; sulfur autotrophic filter layer C 1a , C 1b Sulfur autotrophic filler (particle size 5mm, porosity 60%), C 1a , C 1b The filling thickness is 20 cm; the zeolite filler layer C2 is natural clinoptilolite (particle size 7 mm, porosity 47%), and the filling thickness is 25 cm; the gravel is ordinary building bluestone (particle size 2 cm, porosity 53%), and the filling thickness is 8 cm.

[0054] After the artificial wetland system has been running stably, daily water samples will be collected and analyzed every 2 days, and the water sampling time will be fixed at 08:00-09:00; daily gas samples will be collected and analyzed every 2 days after the artificial wetland system has been running stably, and the gas sampling time will be fixed at 09:00-10:00, and gas sampling will be carried out at 0, 20, 40, and 60 minutes within each hour.

[0055] The calculation formula of N2O emission flux (F) is as follows:

[0056]

[0057] F represents the emission flux (mg·m -2 ·h -1 );dc / dt represents the slope of the curve of gas concentration changing with time;M is the molar mass of N2O (g mol -1 ); P is the gas pressure at the time of sampling (Pa); T is the absolute temperature at the time of sampling (K); Vo, Po, and To represent the molar volume of the gas under standard conditions (mLmol -1 ), air pressure (Pa) and absolute temperature (K); H is the height of the box (m).

[0058] When the sulfur autotrophic filler is 20 cm, the calculation formula for the N2O gas emission flux in the artificial wetland of the present invention is as follows:

[0059] F1=α*F0*h0 / h1=0.95*0.25*0.05 / 0.2=0.059mg·m -2 ·h -1

[0060] G=ρ*(π*d 2 / 4)*h=1.2*(π*d 2 / 4))*0.4=0.377*d 2

[0061] Note: The unit of inner diameter of artificial wetland is m.

[0062] When the sulfur autotrophic filler is 20 cm, the N2O gas emission flux in the artificial wetland of the present invention is 0.059 mg·m -2 ·h -1 .

[0063] Example 2

[0064] The difference from Example 1 is that:

[0065] The artificial wetland is set up from top to bottom in the soil layer, sulfur autotrophic filter layer C 1a , zeolite filler layer C2, sulfur autotrophic filter layer C 1b , gravel support layer; soil layer soil is selected from brown soil, filling thickness is 10cm; sulfur autotrophic filter layer C 1a , C 1b Sulfur autotrophic filler (particle size 5mm, porosity 60%), C 1a , C 1b The filling thickness is 25 cm; the zeolite filler layer C2 is natural clinoptilolite (particle size 7 mm, porosity 47%), and the filling thickness is 25 cm; the gravel is ordinary building bluestone (particle size 2 cm, porosity 53%), and the filling thickness is 8 cm.

[0066] When the sulfur autotrophic filler is 25 cm, the calculation formula for the N2O gas emission flux in the artificial wetland of the present invention is as follows:

[0067] F1=α*F0*h0 / h1=0.95*0.25*0.05 / 0.25=0.0475mg·m -2 ·h -1

[0068] G=ρ*(π*d 2 / 4)*h=1.2*(π*d 2 / 4))*0.4=0.377*d 2

[0069] Note: The unit of inner diameter of artificial wetland is m.

[0070] When the sulfur autotrophic filler is 25 cm, the N2O gas emission flux in the artificial wetland of the present invention is 0.0475 mg·m -2 ·h -1 .

[0071] Example 3

[0072] The difference from Example 1 is that:

[0073] The artificial wetland is set up from top to bottom in the soil layer, zeolite filler layer C 1a , zeolite filler layer C2, sulfur autotrophic filter layer C 1b , gravel support layer; soil layer soil is selected from brown soil, filling thickness is 10cm; sulfur autotrophic filter layer C 1b The zeolite filler layer C is sulfur autotrophic filler (particle size 5 mm, porosity 60%), with a filling thickness of 25 cm; 1a , C2 is natural clinoptilolite (particle size 7 mm, porosity 47%), C 1a , C2 filling thickness is 25cm respectively; the gravel is ordinary building bluestone (particle size 2cm, porosity 53%), and the filling thickness is 10cm.

[0074] Sulfur autotrophic filler only has lower C 1b When the filling volume was 25 cm, the N2O emission flux of the device was monitored to be 0.117 mg·m -2 ·h -1 , compared with Example 2: 0.117 mg·m -2 ·h -1 >0.0475mg·m -2 ·h -1 .

[0075] The N2O emission flux of the artificial wetland device filled with a single layer of sulfur autotrophic filler is higher than that of the artificial wetland device filled with a double layer of sulfur autotrophic filler.

[0076] The utility model provides a concept and method of a sulfur autotrophic filter material artificial wetland nitrous oxide emission reduction device. There are many methods and ways to implement the technical solution. The above is only a preferred embodiment of the utility model. It should be pointed out that for ordinary technicians in this technical field, without departing from the principle of the utility model, several improvements and modifications can be made, and these improvements and modifications should also be regarded as the protection scope of the utility model. All components not specified in this embodiment can be implemented by existing technologies.

Claims

1. A sulfur autotrophic filter material artificial wetland nitrous oxide emission reduction device, characterized in that: The artificial wetland is provided with a soil layer, a sulfur autotrophic filter material layer C in sequence from top to bottom. 1a , zeolite filler layer C2, sulfur autotrophic filter layer C 1b , gravel support layer, of which: An aeration unit is provided at the bottom of the artificial wetland, and the aeration unit includes a microporous aeration pipe provided at the bottom of the device; A gas collecting unit is arranged on the upper part of the artificial wetland; The water inlet and outlet at the bottom and top of the artificial wetland are connected to a water collection tank for controlling the water inlet and outlet of the wetland unit; The water flow of the artificial wetland is an upward flow, and emergent plants are arranged in the soil layer.

2. The device according to claim 1, characterized in that The microporous aeration tube is arranged at 5-6 cm from the bottom of the device, and is connected to the air compressor through an aeration conduit. A flow meter and a timing switch are arranged between the air compressor and the microporous aeration tube to control the aeration amount and aeration time.

3. The device according to claim 1, characterized in that The gas collection unit comprises a water seal groove arranged on the upper part of the artificial wetland, the water seal groove is provided with a static gas sampling box, and the middle part of the static gas sampling box is provided with two gas openings.

4. The device according to claim 1, characterized in that The soil in the soil layer is selected from any one of brick red soil, red soil, red soil or brown soil, and the filling thickness is 5-10 cm.

5. The device according to claim 1, characterized in that The sulfur autotrophic filter material layer C 1a , C 1b It is sulfur autotrophic filler or other self-made sulfur filler, with a filling range of 15-30 cm; The zeolite filler layer C2 is natural clinoptilolite with a particle size of 5 to 10 mm, a porosity of 47%, and a filling thickness range of 10 to 30 cm; The sulfur autotrophic filter material layer C 1a , C 1b and the total height of the zeolite packing layer C2 is 40-90 cm; The gravel support layer is bluestone for construction, with a particle size of 1 to 3 cm, a porosity of 53.00%, and a filling thickness range of 5 to 10 cm; The upper part of the zeolite filler layer C2 is a sulfur autotrophic filter material layer C 1a , the lower part is the sulfur autotrophic filter layer C 1b The sulfur autotrophic filter material layer is sandwiched between the upper and lower parts of the zeolite filler layer C2, which is conducive to the sewage fully contacting the matrix, improving the pollutant removal efficiency, reducing the emission of N2O gas, and extending the operation period of the artificial wetland.

6. The device according to claim 3, characterized in that The emergent plant is Iris pumila, and the planting density is 2 to 3 plants per system.

7. The device according to claim 3, characterized in that An axial flow fan is arranged on the top of the static gas sampling box to mix the air in the box.

8. The device according to claim 1, characterized in that A device supporting layer is arranged at the bottom of the device for supporting the whole device.

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