CN111272948A - Carbon dioxide flux testing device and method for representing natural attenuation process of pollutants - Google Patents
Carbon dioxide flux testing device and method for representing natural attenuation process of pollutants Download PDFInfo
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Abstract
A carbon dioxide flux testing device and method for representing the natural attenuation process of pollutants, the testing device comprises a rainproof ventilation hood and a flux testing cavity which are sequentially connected from top to bottom; the rain-proof ventilation cover is provided with a ventilation hole; the flux test cavity is cylindrical, and at least two layers of carbon dioxide adsorption fillers are sequentially arranged in parallel at intervals from top to bottom in the flux test cavity. The invention provides an in-situ non-disturbance open type testing device and method which are relatively simple in structure, low in device processing and manufacturing cost and concise in testing steps and can monitor the average volatilization flux of carbon dioxide for a long time, and the in-situ non-disturbance open type testing device and method are used for supporting and evaluating whether natural attenuation mainly based on biodegradation exists in soil and underground water of a specific polluted site and whether the natural attenuation can be used as a risk control strategy for pollution of the soil and the underground water of the specific site. Can be widely applied to the characterization of the natural attenuation process of pollutants.
Description
Technical Field
The invention relates to the field of site pollution investigation and risk assessment, in particular to a device and a method for representing a natural attenuation process of pollutants.
Background
Petroleum hydrocarbon is a main raw material and a product of industrial enterprises such as petroleum refining, gas stations, oil depots and the like, and due to leakage of pipelines and storage tanks, the soil and underground water of the sites of the enterprises can be polluted to a certain extent by the petroleum hydrocarbon, and light non-aqueous phase liquid (LNAPL) can also exist in areas with heavier local pollution. For the remediation of these contaminated soils and groundwater, historically, aggressive active remediation has been the mainstay, such as thermal desorption, chemical oxidation, and the like. On the one hand, a large number of engineering practices show that the marginal effect of restoration investment tends to zero due to the influence of the mass transfer rate of pollutants in soil and underground water in the later period of implementation of the restoration facilities, so that the invalid investment of restoration resources is caused. On the other hand, however, increasing research and field monitoring data indicate that such contaminants are highly susceptible to microbial degradation in soil and groundwater, conversion to non-toxic and harmless carbon dioxide and water, and the like. Therefore, on the premise of effectively controlling the environmental and health risks of petroleum hydrocarbon pollutants in soil and underground water in a field, the polluted soil and underground water are gradually repaired and purified by utilizing the degradation capability of microorganisms in the soil and underground water, and the pollution is adopted by more and more mechanisms internationally at present.
However, the first prerequisite for degrading and purifying pollutants by using microorganisms in soil and groundwater is to demonstrate that corresponding microbial degradation activities are indeed occurring in the field by means of monitoring and the like. The concrete demonstration means comprises continuous monitoring and evaluation of the concentration change of the target pollutant for not less than 2 years, monitoring and evaluation of water chemical indexes and microecological indexes which are beneficial to the occurrence of microbial degradation activity, and molecular biological test and analysis evaluation of functional genes and activity thereof. In the process of degrading organic pollutants such as petroleum hydrocarbon and the like by microorganisms, a large amount of carbon dioxide is released, so that the volatilization flux of the carbon dioxide in a polluted area is obviously higher than the flux of the carbon dioxide generated by the respiration of the microorganisms in soil in a clean area. If the test result of the carbon dioxide flux of a petroleum hydrocarbon polluted area of a specific site is obviously higher than the carbon dioxide flux of a clean area in the site, the natural degradation process of microorganisms in the petroleum hydrocarbon in the soil and underground water of the site can be judged to a certain extent. Therefore, testing the volatilization flux of carbon dioxide in a polluted area, and evaluating whether a natural attenuation process mainly based on microbial degradation exists in the field according to a test result is one of the international universal technical means at present.
Although a plurality of carbon dioxide flux testing devices and methods are developed at present in China, the devices and methods are mainly used for measuring the flux of carbon dioxide discharged to the atmosphere in areas such as refuse landfills, farmlands, forests and the like, the testing principle is mainly that a closed flux measuring room is installed at present, the concentration change of the carbon dioxide in the flux room is measured on line through a portable carbon dioxide measuring instrument on site, and finally the volatilization flux of the carbon dioxide is calculated by combining a model. These prior devices and methods generally suffer from the following drawbacks: (1) the testing device is a closed flux measuring chamber, the monitoring result cannot represent the influence of air pressure fluctuation on the volatilization flux of the carbon dioxide under natural conditions, and the testing result is usually distorted; (2) a single set of device usually comprises a closed flux measuring chamber and an on-site carbon dioxide detector, the system is relatively complex, the cost of the single set of device is usually higher than 5 ten thousand yuan, and multi-point tests are difficult to be carried out simultaneously; (3) the field test time is usually several hours to 1 day, belongs to an instantaneous value, and the result is difficult to characterize the influence of the climate factors on the volatilization flux of the carbon dioxide under natural conditions.
Disclosure of Invention
The invention aims to provide a carbon dioxide flux testing device and a carbon dioxide flux testing method for representing a natural attenuation process of pollutants, and aims to solve the technical problems of high cost and low efficiency of the conventional testing device; and the problem of inaccurate measuring results is solved.
In order to achieve the purpose, the invention adopts the following technical scheme:
a carbon dioxide flux testing device for representing a natural attenuation process of pollutants comprises a rainproof ventilation hood and a flux testing cavity which are sequentially connected from top to bottom; the rain-proof ventilation cover is provided with a ventilation hole; the flux test cavity is in a cylindrical shape, and at least two layers of carbon dioxide adsorption fillers are sequentially arranged in parallel at intervals from top to bottom in the flux test cavity, wherein at least one layer of carbon dioxide adsorption filler on the upper layer is used for adsorbing carbon dioxide in the atmosphere, and at least one layer of carbon dioxide adsorption filler on the lower layer is used for adsorbing carbon dioxide released in the natural attenuation process of pollutants. The upper carbon dioxide adsorption filler is used for adsorbing carbon dioxide in the atmosphere, so that the influence caused by environmental factors is eliminated; the bottom layer is used for adsorbing carbon dioxide released by the natural decay process of pollutants in soil and underground water.
And four layers of carbon dioxide adsorption fillers are arranged on the flux testing cavity, wherein the upper two layers of carbon dioxide adsorption fillers are used for adsorbing carbon dioxide in the atmosphere, and the lower two layers of carbon dioxide adsorption fillers are used for adsorbing carbon dioxide released in the natural attenuation process of pollutants. Set up four layers of carbon dioxide adsorption filler and can satisfy general monitoring requirement, from top to bottom be atmosphere carbon dioxide adsorption layer in proper order, atmosphere carbon dioxide confirms the layer, monitor carbon dioxide confirms the layer and monitor carbon dioxide adsorption layer, wherein the topmost layer is the carbon dioxide who is used for adsorbing in the atmosphere, the second floor is used for confirming that the topmost layer is not all to adsorb the carbon dioxide in the atmosphere, the bottommost layer is used for adsorbing the carbon dioxide that soil and groundwater pollutant natural attenuation process released, the third layer is then the insurance consideration: if the concentration is too high, the lowest layer is saturated in adsorption, and the third layer can continue to adsorb. Generally, the probability that the two layers of adsorbents are saturated in adsorption caused by pollutant degradation does not exist basically, and if special conditions exist, an atmospheric carbon dioxide adsorption layer and a monitoring carbon dioxide adsorption layer can be added adaptively.
The flux testing cavity is formed by sequentially butting at least two cavity units from top to bottom; the cavity units are in socket connection or threaded connection; the number of the cavity units is consistent with the number of the carbon dioxide adsorption filler layers, and a layer of carbon dioxide adsorption filler is correspondingly arranged in each cavity unit. Therefore, the flux testing cavity is convenient to transport and install, the sealing performance of the flux testing cavity after installation can be guaranteed, and in the later stage, for better sealing, sealant can be coated at the joint or a sealing ring can be additionally arranged.
The carbon dioxide adsorption filler is uniformly laid on the filler supporting plate; the filler support plate comprises a support bottom plate and a support side plate annularly arranged around the support bottom plate, an accommodating layer paved with carbon dioxide adsorption filler is formed between the support side plate and the support bottom plate, and the thickness of the accommodating layer is not less than 2 mm; the size of the supporting bottom plate is matched with the cross section of the cavity unit; the supporting bottom plate is evenly provided with vent holes. The filler supporting plate is used for laying the carbon dioxide adsorption filler, so that the carbon dioxide adsorption filler can be uniformly laid, and the carbon dioxide adsorption filler can be collected and replaced.
A filler supporting plate supporting ring is arranged in the cavity unit in the circumferential direction and used for supporting the filler supporting plate; and a gap between the cavity unit and the filler supporting plate is filled with a sealing material. The packing support plate is convenient to replace and disassemble, the sealing performance inside the wall body is realized, and the carbon dioxide can be effectively adsorbed and cannot leak from gaps.
The device also comprises a fixed skirt edge; the fixed skirt is cylindrical, and the upper end of the fixed skirt is connected to the bottom of the flux testing cavity; the lower part of the side wall is wedge-shaped and is inserted and fixed in the soil layer of the working surface. The stable connection of this testing arrangement has been realized to the design of fixed shirt rim, ensures the non-disturbed monitoring environment of normal position.
The upper end port of the fixed skirt and the lower end port of the flux testing cavity are both provided with threads and are connected through the threads.
Or the upper end port of the fixed skirt and the lower end port of the flux testing cavity are flush surfaces and are in butt joint and connected through the connecting assembly; the connecting assembly comprises a base plate and a connecting piece; the cushion plate is annularly hooped at the joint position of the fixed skirt edge and the flux testing cavity and is connected with the fixed skirt edge and the flux testing cavity through a connecting piece, and the connecting piece is a bolt, a screw or a split bolt. The connection form of the fixed skirt and the flux testing cavity is convenient to connect, dismantle and replace, and meanwhile, the connection tightness of the fixed skirt and the flux testing cavity is guaranteed.
The rain-proof ventilation hood comprises a conical shell-shaped rain-proof top hood and rain-proof side walls arranged below the rain-proof top hood in an annular mode, wherein at least two ventilation holes are symmetrically formed in the rain-proof side walls; and the lower port of the rainproof side wall is in socket connection or threaded connection with the top port of the flux testing cavity. The two are connected with the convenience and are connected, demolish, change as the standard, and the effect of rain-proof ventilation cover guarantees the ventilation condition when rain-proof, can characterize the influence of atmospheric pressure fluctuation to carbon dioxide volatilization flux under the natural condition, forms the open monitoring environment of normal position for the monitoring result is more accurate.
The method for applying the carbon dioxide flux testing device for characterizing the natural attenuation process of the pollutants is characterized by comprising the following specific steps of:
selecting a monitoring point location in a biodegradable organic matter pollution area according to a site pollution investigation result, and clearing and leveling a working surface of the monitoring point location.
And step two, pressing the fixed skirt edge below the soil layer of the working surface of the monitoring point location.
And step three, connecting the flux testing cavity with the carbon dioxide adsorption filler and the fixed skirt.
And step four, installing the rainproof ventilation hood on the top end of the flux testing cavity.
And fifthly, recording the field installation completion time of the flux testing device, taking out the carbon dioxide adsorption filler of each layer in the flux testing cavity after a monitoring period, respectively placing the carbon dioxide adsorption filler in the sample bottles, sealing the sample bottles, numbering the sample bottles, and sending the samples to a laboratory.
Step six, after the sample is subjected to vacuum drying, recording the mass of each layer of carbon dioxide adsorption filler, wherein the mass of each layer of carbon dioxide adsorption filler dried from top to bottom is m01、m02……m0NAnd N is an integer of not less than 2.
Step seven, titrating by using hydrochloric acid until the carbon dioxide adsorption filler does not generate bubbles any more, and then carrying out vacuum drying on the residual carbon dioxide adsorption filler, wherein the mass of the dried carbon dioxide adsorption filler is m11、m12……m1NAnd N is an integer of not less than 2.
Step eight, calculating the second of each layer by using a difference methodThe content of carbon dioxide adsorbed in the carbon oxide adsorption filler is (m) from top to bottom, and the mass of the carbon dioxide adsorbed in each layer is01-m11）、（m02-m12）……（m0N-m1N) And N is an integer of not less than 2.
And step nine, calculating the sum M of the mass of the carbon dioxide absorbed by the carbon dioxide absorbing filler for absorbing the carbon dioxide released in the natural attenuation process of the pollutants.
Step ten, calculating the volatilization flux of the carbon dioxide at the monitoring point according to the result of the step nine, wherein the specific formula is as follows:
Flux=M/(A×t)；
in the formula: flux is the carbon dioxide volatilization Flux of the test point and has the unit of mg/(m)2·d)。
And M is the sum of the mass of carbon dioxide adsorbed by the carbon dioxide adsorbing filler for adsorbing carbon dioxide released in the natural attenuation process of pollutants, and the unit is mg.
A is the internal surface area of the flux measuring chamber (2) in m2。
And t is the monitoring period of the flux testing device at the monitoring point position, and the unit is d.
In the second step, the fixed skirt edge (3) is pressed into the working surface of the monitoring point to a depth not less than 0.5 m.
Compared with the prior art, the invention has the following characteristics and beneficial effects:
the invention provides an in-situ non-disturbance open type testing device and method which are relatively simple in structure, low in device processing and manufacturing cost and concise in testing steps and can monitor the average volatilization flux of carbon dioxide for a long time, and the in-situ non-disturbance open type testing device and method are used for supporting and evaluating whether natural attenuation mainly based on biodegradation exists in soil and underground water of a specific polluted site and whether the natural attenuation can be used as a risk control strategy for pollution of the soil and the underground water of the specific site.
The method can be widely applied to characterization of the natural attenuation process of pollutants.
Drawings
The present invention will be described in further detail with reference to the accompanying drawings.
Fig. 1 is a schematic cross-sectional structure of a flux testing device of the present invention.
Fig. 2 is a schematic top view of the flux testing apparatus of the present invention.
Fig. 3 is a schematic top view of the rain-proof ventilation hood of the present invention.
Fig. 4 is a schematic sectional structure view of the rain-proof ventilation hood of the invention.
Fig. 5 is a schematic top view of the carbon dioxide adsorbing chamber according to the present invention.
Fig. 6 is a schematic sectional view showing a carbon dioxide adsorbing chamber according to the present invention.
FIG. 7 is a top view of the fixed skirt of the present invention.
FIG. 8 is a schematic cross-sectional view of the fixed skirt of the present invention.
Reference numerals: 1-rainproof ventilation hood, 11-rainproof top hood, 12-rainproof side wall, 13-vent hole, 2-flux test cavity, 21-cavity unit, 3-fixed skirt edge, 4-connecting component, 41-backing plate, 42-connecting component, 5-filler support plate support ring, 6-carbon dioxide adsorption filler, 7-sealing material, 8-filler support plate, 81-support side plate, 82-support bottom plate and 83-vent hole.
Detailed Description
Referring to fig. 1 and fig. 2, the carbon dioxide flux testing device for characterizing the natural decay process of pollutants is characterized in that: comprises a rainproof ventilation hood 1 and a flux testing cavity 2 which are connected in sequence from top to bottom; comprises a rainproof ventilation hood 1 and a flux testing cavity 2 which are connected in sequence from top to bottom; the rainproof ventilation hood 1 is provided with a ventilation hole 13; the flux testing cavity 2 is in a cylindrical shape, and at least two layers of carbon dioxide adsorption fillers 6 are sequentially arranged in parallel at intervals from top to bottom in the flux testing cavity, wherein at least one layer of carbon dioxide adsorption filler 6 on the upper layer is used for adsorbing carbon dioxide in the atmosphere, and at least one layer of carbon dioxide adsorption filler 6 on the lower layer is used for adsorbing carbon dioxide released in the natural attenuation process of pollutants.
In this example, four layers of carbon dioxide adsorption fillers 6 are arranged on the flux test cavity 2, wherein the upper two layers of carbon dioxide adsorption fillers 6 are used for adsorbing carbon dioxide in the atmosphere, and the lower two layers of carbon dioxide adsorption fillers 6 are used for adsorbing carbon dioxide released in the natural attenuation process of pollutants. The carbon dioxide adsorbing filler 6 is a carbon dioxide adsorbent.
Generally, four layers of carbon dioxide adsorption fillers 6 are arranged to meet the monitoring requirement: wherein the uppermost layer is used for adsorbing carbon dioxide in the atmosphere, the second layer is used for confirming whether the uppermost layer adsorbs carbon dioxide in the atmosphere or not, the lowermost layer is used for adsorbing carbon dioxide released by the natural attenuation process of pollutants in soil and groundwater, and the third layer is used for insurance consideration: if the concentration is too high, the lowest layer is saturated in adsorption, and the third layer can continue to adsorb.
Generally, the probability that both layers of adsorbents are saturated by adsorption due to pollutant degradation does not exist basically, so 4 layers are usually arranged, but in consideration of other situations, one or three layers of carbon dioxide adsorption fillers 6 can be arranged at the upper part in a targeted manner for adsorbing carbon dioxide in the atmosphere, one or three layers of carbon dioxide adsorption fillers 6 are arranged at the lower part for adsorbing carbon dioxide released in the natural attenuation process of pollutants, and the design is flexible according to actual conditions.
The flux testing cavity 2 is formed by sequentially butting at least two cavity units 21 from top to bottom; the cavity units 21 are in socket connection or threaded connection; the number of the cavity units 21 is consistent with the number of the layers of the carbon dioxide adsorption filler 6, and a layer of the carbon dioxide adsorption filler 6 is correspondingly arranged in each cavity unit 21.
In this example, the flux testing chamber 2 is formed by connecting four chamber units 21 with the height of 60mm in series in a threaded manner, and the side wall thickness of each chamber unit 21 is 5 mm; the flux test cavity 2 is made of PVC, and has an outer diameter of 200mm, an inner diameter of 190mm and a height of 240 mm.
Referring to fig. 5, the carbon dioxide adsorbing fillers 6 are uniformly laid on the filler supporting plate 8; the packing support plate 8 comprises a support bottom plate 82 and a support side plate 81 annularly arranged around the support bottom plate, and an accommodating layer for laying the carbon dioxide adsorption packing 6 is formed between the support side plate 81 and the support bottom plate 82, and the thickness of the accommodating layer is not less than 2mm, in this example 2 mm; the size of the supporting bottom plate 82 is adapted to the cross section of the cavity unit 21; the support bottom plate 82 is uniformly provided with vent holes 83.
Referring to fig. 6, a filler support plate support ring 5 is annularly arranged inside the cavity unit 21 for supporting a filler support plate 8; the gap between the cavity unit 21 and the supporting plate 8 for supporting the filler is filled with a sealing material 7, in this example, the sealing material 7 is vaseline.
Referring to fig. 7 and 8, the carbon dioxide flux testing device for characterizing the natural attenuation process of pollutants further comprises a fixed skirt 3; the fixed skirt 3 is cylindrical, and the upper end of the fixed skirt is connected to the bottom of the flux testing cavity 2; the lower part of the side wall is wedge-shaped and is inserted and fixed in the soil layer of the working surface. In this example, the fixed skirt 3 is made of stainless steel, and has an outer diameter of 200mm, an inner diameter of 190mm, and a sidewall thickness of 5 mm.
The upper port of the fixed skirt 3 and the lower port of the flux testing cavity 2 are both provided with threads and are connected through the threads; or the upper port of the fixed skirt 3 and the lower port of the flux testing cavity 2 are flush surfaces, and are butted and connected through a connecting component 4; the connecting assembly 4 comprises a backing plate 41 and a connecting piece 42; the backing plate 41 is annularly hooped at the joint position of the fixed skirt 3 and the flux testing cavity 2 and is connected with the fixed skirt 3 and the flux testing cavity 2 through a connecting piece 42, and the connecting piece 42 is a bolt, a screw or a split bolt. In this example, the connecting assembly is used for connection, and the backing plate 41 is a rubber gasket, has a thickness of 5mm and a width of 60mm, and is mainly used for sealing the interface between the fixed skirt and the flux testing cavity 2 after being fastened by the connecting member 42.
Referring to fig. 3 and 4, the rain-proof ventilation hood 1 comprises a conical shell-shaped rain-proof top hood 11 and rain-proof side walls 12 arranged annularly below the rain-proof top hood, wherein at least two ventilation holes 13 are symmetrically formed in the rain-proof side walls 12; the lower port of the rainproof side wall 12 is connected with the top port of the flux testing cavity 2 in a socket-in or threaded manner. In the embodiment, the rain-proof ventilation hood 1 is made of PVC, has an inner diameter of 200mm and a height of 150mm, and is connected with the flux testing cavity 2 in a socket joint mode, so that the connection is more convenient and labor-saving.
A method for applying the carbon dioxide flux testing device for characterizing the natural attenuation process of pollutants takes four layers of carbon dioxide adsorption fillers 6 as an example, and comprises the following specific steps:
selecting a monitoring point location in a biodegradable organic matter pollution area according to a site pollution investigation result, removing the situations of ground hardening and the like of a working surface of the monitoring point location, and leveling; conventionally, the monitoring site is selected according to the detected concentration distribution of pollutants in soil and underground water, and is generally arranged in a heavily polluted area.
And step two, pressing the fixed skirt 3 below a soil layer of a working surface of the monitoring point, wherein the depth of pressing the fixed skirt into the working surface of the monitoring point is not less than 0.5 m.
Thirdly, connecting the flux testing cavity 2 with the carbon dioxide adsorption filler 6 and the fixed skirt 3;
fourthly, mounting the rain-proof ventilation hood 1 on the top end of the flux testing cavity 2;
recording the field installation completion time of the flux testing device, taking out the carbon dioxide adsorption filler 6 of each layer in the flux testing cavity 2 after a monitoring period, respectively placing the carbon dioxide adsorption filler in sample bottles, sealing the sample bottles, numbering the sample bottles and sending the samples to a laboratory; in this example, the monitoring period was 15d, and the sample bottle used was a teflon sample bottle.
Step six, after the sample is subjected to vacuum drying, recording the mass of each carbon dioxide adsorption filler 6, wherein the mass of each layer of carbon dioxide adsorption filler 6 dried from top to bottom is m01、m02、m03And m04。
Step seven, titrating by using hydrochloric acid until the carbon dioxide adsorption filler 6 does not generate bubbles any more, and then carrying out vacuum drying on the residual carbon dioxide adsorption filler, wherein the mass of the dried carbon dioxide adsorption filler is m11、m12、m13And m14。
Step eight, calculating the content of the carbon dioxide adsorbed in the carbon dioxide adsorbing filler 6 of each layer by a difference method, wherein each layer adsorbs from top to bottomRespectively, is (m) as a mass of carbon dioxide01-m11）、（m02-m12）、（m03-m13) And (m)04-m14）；
Step nine, calculating the volatilization flux of the carbon dioxide at the monitoring point according to the mass of the carbon dioxide adsorbed by the carbon dioxide adsorbing fillers 6 on the 3 rd layer and the 4 th layer from top to bottom, wherein the specific formula is as follows: generally, the probability that two layers of adsorbents are saturated due to pollutant degradation does not exist basically, so that when four layers of carbon dioxide adsorption fillers 6 are arranged, the two layers of carbon dioxide adsorption fillers 6 at the bottom are carbon dioxide released in the natural attenuation process of adsorbed pollutants:
Flux=[（m03-m13）+（m04-m14）]/(A×t)；
in the formula: flux is the carbon dioxide volatilization Flux of the test point and has the unit of mg/(m)2·d)。
m03And m13、m04And m14The mass of the carbon dioxide adsorption filler 6 on the 3 rd layer and the 4 th layer from top to bottom before and after the hydrochloric acid titration is respectively, and the unit is mg.
A is the internal surface area of the flux measuring chamber (2) in m2(ii) a The inner surface area refers to the cross-sectional area of the flux testing chamber 2, which is consistent with the cross-sectional area of the fixed skirt.
t is the monitoring period of the flux testing device at the monitoring point, and has the unit of d, which is 15d in the example.
Claims (10)
1. A carbon dioxide flux testing device for characterizing the natural attenuation process of pollutants is characterized in that: comprises a rainproof ventilation hood (1) and a flux testing cavity (2) which are connected in sequence from top to bottom;
the rainproof ventilation hood (1) is provided with a ventilation hole (13);
the flux testing cavity (2) is cylindrical, and at least two layers of carbon dioxide adsorption fillers (6) are sequentially arranged in parallel at intervals from top to bottom in the flux testing cavity, wherein at least one layer of carbon dioxide adsorption filler (6) on the upper layer is used for adsorbing carbon dioxide in the atmosphere, and at least one layer of carbon dioxide adsorption filler (6) on the lower layer is used for adsorbing carbon dioxide released in the natural attenuation process of pollutants.
2. The carbon dioxide flux testing device for characterizing a natural decay process of a contaminant according to claim 1, wherein:
four layers of carbon dioxide adsorption fillers (6) are arranged on the flux testing cavity (2), wherein the upper two layers of carbon dioxide adsorption fillers (6) are used for adsorbing carbon dioxide in the atmosphere, and the lower two layers of carbon dioxide adsorption fillers (6) are used for adsorbing carbon dioxide released in the natural attenuation process of pollutants.
3. A carbon dioxide flux test device for characterizing the natural decay process of a contaminant according to claim 1 or 2, wherein:
the flux testing cavity (2) is formed by sequentially butting at least two cavity units (21) from top to bottom;
the cavity units (21) are in socket connection or threaded connection;
the number of the cavity units (21) is consistent with the number of the layers of the carbon dioxide adsorption filler (6), and a layer of the carbon dioxide adsorption filler (6) is correspondingly arranged in each cavity unit (21).
4. The carbon dioxide flux testing device for characterizing a natural decay process of a contaminant according to claim 3, wherein:
the carbon dioxide adsorption filler (6) is uniformly laid on the filler support plate (8);
the packing support plate (8) comprises a support bottom plate (82) and a support side plate (81) annularly arranged around the support bottom plate, an accommodating layer paved with carbon dioxide adsorption packing (6) is formed between the support side plate (81) and the support bottom plate (82), and the thickness of the accommodating layer is not less than 2 mm;
the size of the supporting bottom plate (82) is adapted to the cross section of the cavity unit (21);
the supporting bottom plate (82) is uniformly provided with vent holes (83).
5. The carbon dioxide flux testing device for characterizing a natural decay process of a contaminant according to claim 4, wherein:
a filler supporting plate supporting ring (5) is arranged in the cavity unit (21) in the circumferential direction and used for supporting a filler supporting plate (8);
and a gap between the cavity unit (21) and the filler supporting plate (8) is filled with a sealing material (7).
6. The carbon dioxide flux testing device for characterizing the natural decay process of pollutants as claimed in any one of claims 2 to 5, wherein: also comprises a fixed skirt (3);
the fixed skirt edge (3) is cylindrical, and the upper end of the fixed skirt edge is connected to the bottom of the flux testing cavity 2;
the lower part of the side wall is wedge-shaped and is inserted and fixed in the soil layer of the working surface.
7. The carbon dioxide flux testing device for characterizing a natural decay process of a contaminant according to claim 6, wherein:
the upper port of the fixed skirt edge (3) and the lower port of the flux testing cavity (2) are both provided with threads and are connected through the threads;
or the upper port of the fixed skirt edge (3) and the lower port of the flux testing cavity (2) are flush surfaces and are in butt joint and connected through the connecting component (4);
the connecting assembly (4) comprises a backing plate (41) and a connecting piece (42), wherein the backing plate (41) is annularly hooped at the joint position of the fixed skirt (3) and the flux testing cavity (2) and is connected with the fixed skirt (3) and the flux testing cavity (2) through the connecting piece (42), and the connecting piece (42) is a bolt, a screw or a split bolt.
8. The carbon dioxide flux testing device for characterizing a natural decay process of a contaminant according to claim 7, wherein:
the rain-proof ventilation hood 1 comprises a conical shell-shaped rain-proof top hood (11) and rain-proof side walls (12) which are annularly arranged below the rain-proof top hood, wherein at least two ventilation holes (13) are symmetrically formed in the rain-proof side walls (12);
the lower port of the rainproof side wall (12) is in socket connection or threaded connection with the top port of the flux testing cavity (2).
9. The method for applying the carbon dioxide flux testing device for characterizing the natural decay process of the pollutants as claimed in any one of claims 1 to 8 is characterized by comprising the following specific steps:
selecting a monitoring point location in a biodegradable organic matter pollution area according to a site pollution investigation result, and clearing and leveling a working surface of the monitoring point location;
pressing the fixed skirt edge (3) below a soil layer of a working surface of the monitoring point location;
thirdly, connecting the flux testing cavity (2) with the carbon dioxide adsorption filler (6) and the fixed skirt edge (3);
fourthly, mounting the rain-proof ventilation hood (1) on the top end of the flux testing cavity (2);
recording the field installation completion time of the flux testing device, taking out the carbon dioxide adsorption filler (6) of each layer in the flux testing cavity (2) after a monitoring period, respectively placing the carbon dioxide adsorption filler in sample bottles, sealing the sample bottles, numbering the sample bottles and sending the samples to a laboratory;
sixthly, after the sample is dried in vacuum, recording the mass of each layer of carbon dioxide adsorption filler (6), wherein the mass of each layer of carbon dioxide adsorption filler (6) dried from top to bottom is m01、m02……m0NN is an integer not less than 2;
step seven, titrating by using hydrochloric acid until the carbon dioxide adsorption filler (6) does not generate bubbles any more, and then carrying out vacuum drying on the residual carbon dioxide adsorption filler, wherein the mass of the dried carbon dioxide adsorption filler is m11、m12……m1NN is an integer not less than 2;
step eight, calculating the content of the carbon dioxide adsorbed in the carbon dioxide adsorbing filler (6) of each layer by a difference method, wherein the mass of the carbon dioxide adsorbed in each layer from top to bottom is (m)01-m11）、（m02-m12）……（m0N-m1N) N is an integer not less than 2;
calculating the sum M of the mass of the carbon dioxide adsorbed by the carbon dioxide adsorbing filler (6) for adsorbing the carbon dioxide released in the natural attenuation process of the pollutants;
step ten, calculating the volatilization flux of the carbon dioxide at the monitoring point according to the result of the step nine, wherein the specific formula is as follows:
Flux=M/(A×t)；
in the formula: flux is the carbon dioxide volatilization Flux of the test point and has the unit of mg/(m)2·d)；
M is the sum of the mass of carbon dioxide absorbed by the carbon dioxide absorbing filler 6 for absorbing carbon dioxide released in the natural attenuation process of pollutants, and the unit is mg;
a is the internal surface area of the flux measuring chamber (2) in m2；
And t is the monitoring period of the flux testing device at the monitoring point position, and the unit is d.
10. The method according to claim 9, characterized by the following specific steps:
in the second step, the fixed skirt edge (3) is pressed into the working surface of the monitoring point to a depth not less than 0.5 m.
Priority Applications (1)
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| CN106053288A (en) * | 2016-08-11 | 2016-10-26 | 北京市环境保护科学研究院 | Apparatus for measuring gas volatilizing flux of soil by adopting spherical passive sampler, and method thereof |
| CN107014951A (en) * | 2017-02-27 | 2017-08-04 | 北京林业大学 | Forest ecosystem breathes Carbon flux assay method |
| CN107024405A (en) * | 2017-02-28 | 2017-08-08 | 北京大学 | A kind of carbon dioxide field capturing device for monitoring organic contaminants in soil degraded |
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| CN106053288A (en) * | 2016-08-11 | 2016-10-26 | 北京市环境保护科学研究院 | Apparatus for measuring gas volatilizing flux of soil by adopting spherical passive sampler, and method thereof |
| CN107014951A (en) * | 2017-02-27 | 2017-08-04 | 北京林业大学 | Forest ecosystem breathes Carbon flux assay method |
| CN107024405A (en) * | 2017-02-28 | 2017-08-08 | 北京大学 | A kind of carbon dioxide field capturing device for monitoring organic contaminants in soil degraded |
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