Risk assessment method and device for solid waste backfilling

Abstract

The invention discloses a risk assessment method and device for solid waste backfilling, and belongs to the field of pollution risk assessment. The method comprises the following steps: carrying out a columnar leaching experiment by utilizing a sample of the solid waste filler for backfilling to obtain a leaching curve, and obtaining the leaching concentration of concerned pollutants in the solid waste filler for backfilling according to the leaching curve; and calculating the concentration of the concerned pollutants in the backfill solid waste filler when the concerned pollutants are transported to the underground water, and carrying out health risk assessment on the underground water exposure path by utilizing the concentration of the concerned pollutants in the backfill solid waste filler when the concerned pollutants are transported to the underground water. According to the method, the local rainfall over the years is considered, concentration prediction of concerned pollutants can be accurately carried out, and accurate health risk assessment is carried out.

Description

Technical Field

[0001] The invention belongs to the field of pollution risk assessment, and in particular relates to a solid waste backfill risk assessment method and device. Background Art

[0002] In actual production, solid waste backfilling scenes often occur. After rainfall, these solid wastes will seep some pollutants into the groundwater, posing certain risks to human health.

[0003] However, conducting a health risk assessment after pollutants have already flowed into groundwater will cause delays and may also lead to an irreversible situation. Therefore, it is necessary to assess the health risks of groundwater exposure pathways in solid waste backfill scenarios in advance before pollution occurs.

[0004] The current method is usually to take a solid waste sample, place it in a container, continuously turn it over and shake it to produce liquid, and then measure the concentration of pollutants in the liquid.

[0005] However, this method is rather cumbersome and does not take into account the impact of local rainfall on pollutant emissions, resulting in inaccurate pollutant concentrations. Summary of the invention

[0006] In order to solve the technical problems existing in the prior art, the present invention provides a risk assessment method for solid waste backfilling, comprising the following steps: (1) Conduct column leaching experiments using samples of solid waste backfill to obtain leaching curves. Based on the leaching curves, obtain the leaching concentrations of the pollutants of concern in the solid waste backfill.

[0007] (2) Calculate the concentration of pollutants of concern in the solid waste backfill when they migrate to groundwater; (3) Conduct a health risk assessment of groundwater exposure pathways using the concentration of pollutants of concern in the backfill solid waste when they migrate to groundwater.

[0008] Preferably, in step (1), a leaching curve is obtained by fitting the total volume of the leaching agent in the column leaching experiment and the measured instantaneous concentration of the pollutant of interest in the leaching solution. The leaching curve is represented by the following formula:

[0009] Where: C i is the instantaneous concentration of the pollutant of concern in the leachate, mg / L; C0, k is the leaching coefficient, dimensionless, and V is the total volume of the extractant, L.

[0010] Preferably, in step (1), obtaining the leaching concentration of the pollutant of concern in the solid waste filler for backfill according to the leaching curve specifically includes: According to the leaching curve, the total amount of pollutants released from the solid waste filling material for backfilling is obtained using the following formula:

[0011] Where: is the total amount of leaching release of pollutants of concern in the solid waste filling material for backfill, mg; is the total mass of solid waste filling material for backfilling, kg; is the mass of solid waste filling material used in the experiment, kg; is the leaching release coefficient, dimensionless, ; The time T when the ratio of rainfall accumulation to solid waste mass reaches the experimental liquid-solid ratio is calculated using the following formula:

[0012] Where: is the area occupied by solid waste backfill, m 2 ; is the average annual rainfall, mm; is the water permeability of solid waste, dimensionless; is the liquid-to-solid ratio of the leaching experiment, mL / kg, which is calculated based on the mass of the solid waste filler and the leaching agent used in the experiment; The following formula is used to calculate the leaching concentration of pollutants of concern in solid waste backfill:

[0013] It is the leaching concentration of pollutants of concern in solid waste filling materials for backfill, mg / L.

[0014] Preferably, in step (2), the following formula is used to calculate the concentration of pollutants in the solid waste filling material when it migrates to the groundwater: :

[0015] in: The concentration of pollutants in the solid waste filling material when it is transported to the groundwater, mg / L; is the leaching factor for the transport of pollutants into groundwater, dimensionless; L1 is the thickness of the solid waste backfill layer, m; L2 is the distance from the top of the solid waste backfill layer to the groundwater, m; Among them, the leaching factor of pollutants transported into groundwater is calculated using the following formula:

[0016] in, is the Darcy velocity of groundwater, cm / a, where a represents year; is the thickness of the groundwater mixing zone, cm; is the infiltration rate of water in the soil, cm / a, where a represents year; is the width of the pollution source area, cm.

[0017] Preferably, in step (3), the carcinogenic risk and non-carcinogenic risk of the drinking groundwater pathway are calculated using the concentration of pollutants in the backfill solid waste filling material when they are transported to the groundwater and the groundwater exposure corresponding to the drinking groundwater pathway, and a health risk assessment of the groundwater exposure pathway is performed.

[0018] Preferably, the cancer risk from drinking groundwater is calculated using the following formula:

[0019] Where: is the carcinogenic risk from drinking groundwater, dimensionless; is the carcinogenic exposure of groundwater corresponding to drinking the affected groundwater, (L / kg) / d, where d means day, is the concentration of pollutants in groundwater, mg / L; is the carcinogenic slope factor for oral intake, (mg / (kg·d)) -1 .

[0020] Preferably, drinking the affected groundwater corresponds to a carcinogenic exposure to groundwater The calculation is done using the following formula:

[0021] Where: is the daily water intake of adults, L / d; is the exposure period for adults, and a represents years; is the exposure frequency for adults, d / a; is the adult weight, kg; is the average time of carcinogenic effect, and d represents days.

[0022] Preferably, the non-carcinogenic risk of drinking groundwater is calculated using the following formula:

[0023] Where: is the hazard entropy of drinking groundwater pathway, dimensionless; is the non-carcinogenic exposure to groundwater corresponding to drinking the affected groundwater, (L / kg) / d; is the reference dose for oral intake, (mg / kg·d); is the reference dose distribution ratio for exposure to groundwater, dimensionless.

[0024] Preferably, drinking the affected groundwater corresponds to a non-carcinogenic exposure to groundwater The calculation is performed using the following formula:

[0025] Where: is the daily water intake of adults, L / d, d means day; is the exposure period for adults, and a represents years; is the exposure frequency for adults, d / a; is the adult weight, kg; is the average time of non-carcinogenic effect, d.

[0026] The present invention also provides a risk assessment device for solid waste backfilling, which is used to implement the above-mentioned risk assessment method for solid waste backfilling, comprising: a leaching experiment device, a measuring device, a memory, a controller and a processor; the leaching experiment device, the measuring device and the memory are respectively connected to the processor; The leaching experiment device comprises: a leaching column, a leaching agent container, a peristaltic pump and a leaching liquid collecting device; the leaching agent container is connected to the peristaltic pump, and the peristaltic pump is passed from the bottom of the leaching column into the leaching column through a pipeline; the leaching liquid collecting device is connected to the top of the leaching column; The measuring device is connected to the peristaltic pump and the leachate collecting device to measure the volume of the extractant and the leachate composition; The memory stores the data of solid waste filling materials for backfilling and the local rainfall data over the years; The controller controls the peristaltic pump to provide leaching agents with different volume gradients according to the local rainfall data over the years stored in the memory, so as to provide the processor with leaching curve fitting; The processor collects leachate data from the leachate collection device and analyzes it, and obtains a leaching curve by fitting; at the same time, obtains backfill solid waste filling material data from the storage device, and obtains the leaching concentration of the pollutants of concern in the backfill solid waste filling material according to the leaching curve; calculates the concentration of the pollutants of concern in the backfill solid waste filling material when they migrate to groundwater; and uses the concentration of the pollutants of concern in the backfill solid waste filling material when they migrate to groundwater to conduct a health risk assessment of the groundwater exposure pathway.

[0027] Preferably, the solid waste filling column in the leaching column has a height of 250-350 mm, an inner diameter of 40-60 mm, and a wall thickness of 4-6 mm.

[0028] Preferably, the thickness of the quartz sand is 1.8-2.5 cm.

[0029] Compared with the prior art, the present invention has the following beneficial effects: 1. The present invention evaluates the health risks of groundwater exposure pathways in solid waste backfill scenarios through leaching experiments, provides leaching agents of different gradients according to local rainfall over the years, performs leaching curve fitting, and ultimately obtains the accurate concentration of pollutants when they enter groundwater, thereby performing accurate health risk assessment.

[0030] 2. The present invention innovatively provides a method for calculating the leaching concentration of pollutants of concern in solid waste fillers for backfill, which can accurately calculate the concentration of pollutants of concern and ultimately accurately conduct health risk assessment. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 This is a flow chart of the risk assessment method for solid waste backfilling of the present invention. DETAILED DESCRIPTION

[0032] 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. The described embodiments 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 creative work are within the scope of protection of the present invention.

[0033] like Figure 1 As shown, the present invention provides a risk assessment method for solid waste backfilling, comprising the following steps: (1) Conduct column leaching experiments using samples of solid waste backfill to obtain leaching curves. Based on the leaching curves, obtain the leaching concentrations of the pollutants of concern in the solid waste backfill.

[0034] (2) Calculate the concentration of pollutants of concern in the solid waste backfill when they migrate to groundwater; (3) Conduct a health risk assessment of groundwater exposure pathways using the concentration of pollutants of concern in the backfill solid waste when they migrate to groundwater.

[0035] Furthermore, in step (1), a leaching curve is obtained by fitting the total volume of the leaching agent in the column leaching experiment and the measured instantaneous concentration of the pollutant of interest in the leaching solution. The leaching curve is expressed by the following formula:

[0036] Where: C i is the instantaneous concentration of the pollutant of concern in the leachate, mg / L; C0, k is the leaching coefficient, dimensionless, and V is the total volume of the extractant, L.

[0037] Furthermore, in step (1), obtaining the leaching concentration of the pollutant of concern in the solid waste filling material for backfill according to the leaching curve specifically includes: According to the leaching curve, the total amount of pollutants released from the solid waste filling material for backfilling is obtained using the following formula:

[0038] Where: is the total amount of leaching release of pollutants of concern in the solid waste filling material for backfill, mg; is the total mass of solid waste filling material for backfilling, kg; is the mass of solid waste filling material used in the experiment, kg; is the leaching release coefficient, dimensionless, ; The time T when the ratio of rainfall accumulation to solid waste mass reaches the experimental liquid-solid ratio is calculated using the following formula:

[0039] Where: is the area occupied by solid waste backfill, m 2 ; is the average annual rainfall, mm; is the water permeability of solid waste, dimensionless; is the liquid-to-solid ratio of the leaching experiment, mL / kg, which is calculated based on the mass of the solid waste filler and the leaching agent used in the experiment; The following formula is used to calculate the leaching concentration of pollutants of concern in solid waste backfill:

[0040] It is the leaching concentration of pollutants of concern in solid waste filling materials for backfill, mg / L.

[0041] Furthermore, in step (2), the following formula is used to calculate the concentration of pollutants in the solid waste filling material when it migrates to the groundwater: :

[0042] in: The concentration of pollutants in the solid waste filling material when it is transported to the groundwater, mg / L; is the leaching factor for the transport of pollutants into groundwater, dimensionless; L1 is the thickness of the solid waste backfill layer, m; L2 is the distance from the top of the solid waste backfill layer to the groundwater, m; Among them, the leaching factor of pollutants transported into groundwater is calculated using the following formula:

[0043] in, is the Darcy velocity of groundwater, cm / a, where a represents year; is the thickness of the groundwater mixing zone, cm; is the infiltration rate of water in the soil, cm / a, where a represents year; is the width of the pollution source area, cm.

[0044] Furthermore, in step (3), the concentration of pollutants in the backfill solid waste when they migrate to groundwater and the groundwater exposure corresponding to the drinking groundwater pathway are used to calculate the carcinogenic risk and non-carcinogenic risk of the drinking groundwater pathway, and a health risk assessment of the groundwater exposure pathway is performed.

[0045] Furthermore, the cancer risk from drinking groundwater is calculated using the following formula:

[0046] Where: is the carcinogenic risk from drinking groundwater, dimensionless; is the carcinogenic exposure of groundwater corresponding to drinking the affected groundwater, (L / kg) / d, where d means day, is the concentration of pollutants in groundwater, mg / L; is the carcinogenic slope factor for oral intake, (mg / (kg·d)) -1 .

[0047] Furthermore, the carcinogenic exposure to groundwater corresponding to drinking the affected groundwater The calculation is done using the following formula:

[0048] Where: is the daily water intake of adults, L / d; is the exposure period for adults, and a represents years; is the exposure frequency for adults, d / a; is the adult weight, kg; is the average time of carcinogenic effect, and d represents days.

[0049] Furthermore, the non-carcinogenic risk from drinking groundwater was calculated using the following formula:

[0050] Where: is the hazard entropy of drinking groundwater pathway, dimensionless; is the non-carcinogenic exposure to groundwater corresponding to drinking the affected groundwater, (L / kg) / d; is the reference dose for oral intake, (mg / kg·d); is the reference dose distribution ratio for exposure to groundwater, dimensionless.

[0051] Furthermore, the non-carcinogenic exposure to groundwater corresponding to drinking the affected groundwater The calculation is performed using the following formula:

[0052] Where: is the daily water intake of adults, L / d, d means day; is the exposure period for adults, and a represents years; is the exposure frequency for adults, d / a; is the adult weight, kg; is the average time of non-carcinogenic effect, d.

[0053] The present invention also provides a risk assessment device for solid waste backfilling, which is used to implement the above-mentioned risk assessment method for solid waste backfilling, comprising: a leaching experiment device, a measuring device, a memory, a controller and a processor; the leaching experiment device, the measuring device and the memory are respectively connected to the processor; The leaching experiment device comprises: a leaching column, a leaching agent container, a peristaltic pump and a leaching liquid collecting device; the leaching agent container is connected to the peristaltic pump, and the peristaltic pump is passed from the bottom of the leaching column into the leaching column through a pipeline; the leaching liquid collecting device is connected to the top of the leaching column; The measuring device is connected to the peristaltic pump and the leachate collecting device to measure the volume of the extractant and the leachate composition; The memory stores the data of solid waste filling materials for backfilling and the local rainfall data over the years; The controller controls the peristaltic pump to provide leaching agents with different volume gradients according to the local rainfall data over the years stored in the memory, so as to provide the processor with leaching curve fitting; The processor collects leachate data from the leachate collection device and analyzes it, and obtains a leaching curve by fitting; at the same time, obtains backfill solid waste filling material data from the storage device, and obtains the leaching concentration of the pollutants of concern in the backfill solid waste filling material according to the leaching curve; calculates the concentration of the pollutants of concern in the backfill solid waste filling material when they migrate to groundwater; and uses the concentration of the pollutants of concern in the backfill solid waste filling material when they migrate to groundwater to conduct a health risk assessment of the groundwater exposure pathway.

[0054] Furthermore, the solid waste filling column in the leaching column has a height of 250-350 mm, an inner diameter of 40-60 mm, and a wall thickness of 4-6 mm.

[0055] Furthermore, the thickness of the quartz sand is 1.8-2.5 cm.

[0056] Example 1 The present invention provides a solid waste backfill risk assessment method, comprising the following steps: (1) Conduct column leaching experiments using samples of solid waste backfill to obtain leaching curves. Based on the leaching curves, obtain the leaching concentrations of the pollutants of concern in the solid waste backfill.

[0057] (2) Calculate the concentration of pollutants of concern in the solid waste backfill when they migrate to groundwater; (3) Conduct a health risk assessment of groundwater exposure pathways using the concentration of pollutants of concern in the backfill solid waste when they migrate to groundwater.

[0058] Example 2 The present invention provides a solid waste backfill risk assessment method, comprising the following steps: (1) Conduct column leaching experiments using samples of solid waste backfill to obtain leaching curves. Based on the leaching curves, obtain the leaching concentrations of the pollutants of concern in the solid waste backfill.

[0059] (2) Calculate the concentration of pollutants of concern in the solid waste backfill when they migrate to groundwater; (3) Conduct a health risk assessment of groundwater exposure pathways using the concentration of pollutants of concern in the backfill solid waste when they migrate to groundwater.

[0060] The column leaching experiment was carried out using the following method: Selecting experimental samples: crushing the solid waste filling material samples for backfilling, and sieving to obtain experimental samples with a preset particle size; Preparing a leaching column: filling the experimental sample to obtain a solid waste filling column of a preset size, and adding quartz sand of a preset thickness to the bottom and top of the solid waste filling column; Conduct leaching experiment: place the leaching column on the surface, inject the leaching agent vertically upward from the bottom of the leaching column at a constant flow rate, provide the leaching agent with different volume gradients, and collect the leaching liquid from the top of the leaching column; different volume gradients are set according to the local rainfall over the years; Leachate data analysis: The leaching curve is fitted based on the volume of the extractant and the measured concentration of the pollutant of interest in the leachate.

[0061] Example 3 The present invention provides a solid waste backfill risk assessment method, comprising the following steps: (1) Conduct column leaching experiments using samples of solid waste backfill to obtain leaching curves. Based on the leaching curves, obtain the leaching concentrations of the pollutants of concern in the solid waste backfill.

[0062] (2) Calculate the concentration of pollutants of concern in the solid waste backfill when they migrate to groundwater; (3) Conduct a health risk assessment of groundwater exposure pathways using the concentration of pollutants of concern in the backfill solid waste when they migrate to groundwater.

[0063] The difference from Example 1 and Example 2 is that: Furthermore, in step (1), a leaching curve is obtained by fitting the total volume of the leaching agent in the column leaching experiment and the measured instantaneous concentration of the pollutant of interest in the leaching solution. The leaching curve is expressed by the following formula:

[0064] Where: C i is the instantaneous concentration of the pollutant of concern in the leachate, mg / L; C0, k is the leaching coefficient, dimensionless, and V is the total volume of the extractant, L.

[0065] Furthermore, in step (1), obtaining the leaching concentration of the pollutant of concern in the solid waste filling material for backfill according to the leaching curve specifically includes: According to the leaching curve, the total amount of pollutants released from the solid waste filling material for backfilling is obtained using the following formula:

[0066] Where: is the total amount of leaching release of pollutants of concern in the solid waste filling material for backfill, mg; is the total mass of solid waste filling material for backfilling, kg; is the mass of solid waste filling material used in the experiment, kg; is the leaching release coefficient, dimensionless, ; The time T when the ratio of rainfall accumulation to solid waste mass reaches the experimental liquid-solid ratio is calculated using the following formula:

[0067] Where: is the area occupied by solid waste backfill, m 2 ; is the average annual rainfall, mm; is the water permeability of solid waste, dimensionless; is the liquid-to-solid ratio of the leaching experiment, mL / kg, which is calculated based on the mass of the solid waste filler and the leaching agent used in the experiment; The following formula is used to calculate the leaching concentration of pollutants of concern in solid waste backfill:

[0068] It is the leaching concentration of pollutants of concern in solid waste filling materials for backfill, mg / L.

[0069] Furthermore, in step (2), the following formula is used to calculate the concentration of pollutants in the solid waste filling material when it migrates to the groundwater: :

[0070] in: The concentration of pollutants in the solid waste filling material when it is transported to the groundwater, mg / L; is the leaching factor for the transport of pollutants into groundwater, dimensionless; L1 is the thickness of the solid waste backfill layer, m; L2 is the distance from the top of the solid waste backfill layer to the groundwater, m; Among them, the leaching factor of pollutants transported into groundwater is calculated using the following formula:

[0071] in, is the Darcy velocity of groundwater, cm / a, where a represents year; is the thickness of the groundwater mixing zone, cm; is the infiltration rate of water in the soil, cm / a, where a represents year; is the width of the pollution source area, cm.

[0072] Furthermore, in step (3), the concentration of pollutants in the backfill solid waste when they migrate to groundwater and the groundwater exposure corresponding to the drinking groundwater pathway are used to calculate the carcinogenic risk and non-carcinogenic risk of the drinking groundwater pathway, and a health risk assessment of the groundwater exposure pathway is performed.

[0073] Furthermore, the cancer risk from drinking groundwater is calculated using the following formula:

[0074] Where: is the carcinogenic risk from drinking groundwater, dimensionless; is the carcinogenic exposure of groundwater corresponding to drinking the affected groundwater, (L / kg) / d, where d means day, is the concentration of pollutants in groundwater, mg / L; is the carcinogenic slope factor for oral intake, (mg / (kg·d)) -1 .

[0075] Furthermore, the carcinogenic exposure to groundwater corresponding to drinking the affected groundwater The calculation is done using the following formula:

[0076] Where: is the daily water intake of adults, L / d; is the exposure period for adults, and a represents years; is the exposure frequency for adults, d / a; is the adult weight, kg; is the average time of carcinogenic effect, and d represents days.

[0077] Furthermore, the non-carcinogenic risk from drinking groundwater was calculated using the following formula:

[0078] Where: is the hazard entropy of drinking groundwater pathway, dimensionless; is the non-carcinogenic exposure to groundwater corresponding to drinking the affected groundwater, (L / kg) / d; is the reference dose for oral intake, (mg / kg·d); is the reference dose distribution ratio for exposure to groundwater, dimensionless.

[0079] Furthermore, the non-carcinogenic exposure to groundwater corresponding to drinking the affected groundwater The calculation is performed using the following formula:

[0080] Where: is the daily water intake of adults, L / d, d means day; is the exposure period for adults, and a represents years; is the exposure frequency for adults, d / a; is the adult weight, kg; is the average time of non-carcinogenic effect, d.

[0081] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention are included in the protection scope of the present invention.

Claims

1. A risk assessment method for solid waste backfilling, characterized in that: The steps include: (1) Conducting column leaching experiments using samples of solid waste backfill to obtain leaching curves, and obtaining leaching concentrations of pollutants of concern in the solid waste backfill based on the leaching curves; (2) Calculate the concentration of pollutants of concern in the solid waste backfill when they migrate to groundwater; (3) Conduct a health risk assessment of groundwater exposure pathways using the concentration of pollutants of concern in the backfill solid waste when they migrate to groundwater.

2. The solid waste backfill risk assessment method according to claim 1, characterized in that: In step (1), the leaching curve is obtained by fitting the total volume of the leaching agent in the column leaching experiment and the measured instantaneous concentration of the pollutant of interest in the leaching liquid. The leaching curve is expressed by the following formula: Where: C i is the instantaneous concentration of the pollutant of interest in the leaching solution, mg / L; C0, k is the leaching coefficient, dimensionless, is the total volume of the extractant, L.

3. The solid waste backfill risk assessment method according to claim 2, characterized in that: In step (1), obtaining the leaching concentration of the pollutant of concern in the solid waste filling material for backfill according to the leaching curve specifically includes: According to the leaching curve, the total amount of pollutants released from the solid waste filling material for backfilling is obtained using the following formula: Where: is the total amount of leaching release of pollutants of concern in the solid waste filling material for backfill, mg; is the total mass of solid waste filling material for backfilling, kg; is the mass of solid waste filling material used in the experiment, kg; is the leaching release coefficient, dimensionless, ; The time T when the ratio of rainfall accumulation to solid waste mass reaches the experimental liquid-solid ratio is calculated using the following formula: Where: is the area occupied by solid waste backfill, m 2 ; is the average annual rainfall, mm; is the water permeability of solid waste, dimensionless; is the liquid-to-solid ratio of the leaching experiment, mL / kg, which is calculated based on the mass of the solid waste filler and the leaching agent used in the experiment; The following formula is used to calculate the leaching concentration of pollutants of concern in solid waste backfill: It is the leaching concentration of pollutants of concern in solid waste filling materials for backfill, mg / L.

4. The solid waste backfill risk assessment method according to claim 3, characterized in that: In step (2), the following formula is used to calculate the concentration of pollutants in the solid waste filling material when it migrates to the groundwater: : in: The concentration of pollutants in the solid waste filling material when it is transported to the groundwater, mg / L; is the leaching factor for the transport of pollutants into groundwater, dimensionless; L1 is the thickness of the solid waste backfill layer, m; L2 is the distance from the top of the solid waste backfill layer to the groundwater, m; Among them, the leaching factor of pollutants transported into groundwater is calculated using the following formula: in, is the Darcy velocity of groundwater, cm / a, where a represents year; is the thickness of the groundwater mixing zone, cm; is the infiltration rate of water in the soil, cm / a, where a represents year; is the width of the pollution source area, cm.

5. The solid waste backfill risk assessment method according to any one of claims 1 to 4, characterized in that: In step (3), the concentration of pollutants in the backfill solid waste when they are transported to the groundwater and the groundwater exposure corresponding to the drinking groundwater pathway are used to calculate the carcinogenic risk and non-carcinogenic risk of the drinking groundwater pathway, and a health risk assessment of the groundwater exposure pathway is performed.

6. The solid waste backfill risk assessment method according to claim 5, characterized in that: The cancer risk from drinking groundwater is calculated using the following formula: Where: is the carcinogenic risk from drinking groundwater, dimensionless; is the carcinogenic exposure of groundwater corresponding to drinking the affected groundwater, (L / kg) / d, where d means day, is the concentration of pollutants in groundwater, mg / L; is the carcinogenic slope factor for oral intake, (mg / (kg·d)) -1 .

7. The solid waste backfill risk assessment method according to claim 6, characterized in that: Carcinogenic exposure to groundwater corresponding to drinking affected groundwater The calculation is done using the following formula: Where: is the daily water intake of adults, L / d; is the exposure period for adults, and a represents years; is the exposure frequency for adults, d / a; is the adult weight, kg; is the average time of carcinogenic effect, and d represents days.

8. The solid waste backfill risk assessment method according to claim 5, characterized in that: The non-cancer risk from drinking groundwater is calculated using the following formula: Where: is the hazard entropy of drinking groundwater pathway, dimensionless; is the non-carcinogenic exposure to groundwater corresponding to drinking the affected groundwater, (L / kg) / d; is the reference dose for oral intake, (mg / kg·d); is the reference dose distribution ratio for exposure to groundwater, dimensionless.

9. The solid waste backfill risk assessment method according to claim 8, characterized in that: Non-carcinogenic groundwater exposure corresponding to drinking affected groundwater The calculation is performed using the following formula: Where: is the daily water intake of adults, L / d, d means day; is the exposure period for adults, and a represents years; is the exposure frequency for adults, d / a; is the adult weight, kg; is the average time of non-carcinogenic effect, d.

10. A risk assessment device for solid waste backfilling, characterized in that: A risk assessment method for solid waste backfilling according to any one of claims 1 to 9, comprising: a leaching experimental device, a measuring device, a memory, a controller and a processor; the leaching experimental device, the measuring device and the memory are respectively connected to the processor; The leaching experiment device comprises: a leaching column, a leaching agent container, a peristaltic pump and a leaching liquid collecting device; the leaching agent container is connected to the peristaltic pump, and the peristaltic pump is passed from the bottom of the leaching column into the leaching column through a pipeline; the leaching liquid collecting device is connected to the top of the leaching column; The measuring device is connected to the peristaltic pump and the leachate collecting device to measure the volume of the extractant and the leachate composition; The memory stores the solid waste filling material data for backfilling and the local rainfall data over the years; The controller controls the peristaltic pump to provide leaching agents with different volume gradients according to the local rainfall data over the years stored in the memory, so as to provide the processor with leaching curve fitting; The processor collects leachate data from the leachate collection device and analyzes it, and obtains a leaching curve by fitting; at the same time, obtains backfill solid waste filling material data from the storage device, and obtains the leaching concentration of the pollutants of concern in the backfill solid waste filling material according to the leaching curve; calculates the concentration of the pollutants of concern in the backfill solid waste filling material when they migrate to groundwater; and uses the concentration of the pollutants of concern in the backfill solid waste filling material when they migrate to groundwater to conduct a health risk assessment of the groundwater exposure pathway.

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