An ex-situ remediation system for water-bearing soil

Abstract

This invention relates to the field of soil treatment technology, specifically to an ex-situ remediation system for water-bearing soil, comprising: a screening unit, an electro-osmotic dehydration unit, a preheating unit, an ex-situ thermal desorption unit, a cooling unit, and a leaching unit connected in sequence. The screening unit separates the soil to be treated into a first-class soil and a second-class soil; the electro-osmotic dehydration unit separates the first-class soil into anodic soil and cathodic soil; the preheating unit preheats the soil; the ex-situ thermal desorption unit removes organic matter; the cooling unit cools the soil; the leaching unit is divided into an anodic soil leaching unit and a cathodic soil leaching unit; the anodic soil leaching unit and the cathodic soil leaching unit leach the anodic soil and the cathodic soil respectively; the concentration of the leaching solution in the anodic soil leaching unit is lower than the concentration of the leaching solution in the cathodic soil leaching unit; this application couples electro-osmotic dehydration, ex-situ thermal desorption, and chemical leaching to remove organic matter and heavy metals. Different concentrations of leaching solution are used to leach the anodic soil and the cathodic soil; this improves the soil remediation effect and saves costs.

Description

Technical Field

[0001] This invention relates to the field of soil treatment technology, and more specifically to an ex-situ remediation system for water-bearing soil. Background Technology

[0002] The land has been contaminated with high concentrations of organic matter and the heavy metal cadmium produced by industry, resulting in soil with combined organic and heavy metal cadmium pollution. This type of soil with combined pollution poses a significant threat to the environment and human health.

[0003] For soil contaminated with the heavy metal cadmium, leaching technology is mainly used, but it has the drawback of high leaching cost. Summary of the Invention

[0004] Therefore, the technical problem to be solved by the present invention is to overcome the drawback of high leaching cost when using leaching technology to treat soil contaminated with heavy metal cadmium.

[0005] To overcome the above-mentioned shortcomings, the present invention provides an ex-situ remediation system for water-bearing soil, comprising:

[0006] The screening unit is adapted to screen the soil to be treated into a first type of soil and a second type of soil; the particle size of the first type of soil is smaller than that of the second type of soil.

[0007] An electro-osmotic dewatering unit is connected to a screening unit; the electro-osmotic dewatering unit is adapted to receive a first type of soil and separate the first type of soil into anodic soil and cathodic soil.

[0008] A preheating unit is connected to an electro-osmotic dehydration unit. The preheating unit is adapted to receive anodic soil and cathodic soil respectively, and to preheat the anodic soil and cathodic soil respectively for dehydration and preliminary removal of organic matter.

[0009] An ex-situ thermal desorption unit is connected to a preheating unit, and a rotary kiln is provided in the ex-situ thermal desorption unit; the ex-situ thermal desorption unit is adapted to receive preheated anodic soil and cathodic soil respectively, and to perform ex-situ thermal desorption on the anodic soil and cathodic soil respectively to remove organic matter;

[0010] A cooling unit is connected to an ex-situ thermal desorption unit; the cooling unit is adapted to receive the anodic soil and cathodic soil after ex-situ thermal desorption respectively, and to cool the anodic soil and cathodic soil respectively.

[0011] The rinsing unit is connected to both the cooling unit and the screening unit. The rinsing unit is divided into an anolyte rinsing unit and a cathodic soil rinsing unit. The anolyte rinsing unit is adapted to receive cooled anolyte and rinse it to remove heavy metals. The cathodic soil rinsing unit is adapted to receive cooled cathodic soil and second-class soil and rinse them to remove heavy metals. A first concentration of rinsing solution is sprayed into the anolyte rinsing unit, and a second concentration of rinsing solution is sprayed into the cathodic soil rinsing unit. The first concentration is less than the second concentration.

[0012] Optionally, the preheating unit is connected to the rotary kiln via a waste heat collection unit; the waste heat collection unit is adapted to collect waste heat in the rotary kiln and then supply it to the preheating unit.

[0013] Optionally, the rotary kiln is provided with an extraction unit; the extraction unit is adapted to extract gases and organic pollutants from inside the rotary kiln.

[0014] The extraction unit is connected to an exhaust gas treatment unit; the exhaust gas treatment unit is suitable for filtering dust and organic pollutants.

[0015] The waste gas treatment unit delivers the treated gas to the rotary kiln via an air supply unit.

[0016] Optionally, the electro-osmotic dehydration unit is provided with a soil transport channel; the waste heat of the preheating unit is transported to the soil transport channel; an exhaust pipe is provided on the preheating unit, and the exhaust pipe is connected to the waste gas treatment unit; the exhaust pipe is adapted to form a negative pressure to extract water vapor and organic matter in the preheating unit and the soil transport channel.

[0017] Optionally, the rotary kiln is connected to a cooling unit via a cooling transmission channel; the cooling unit includes a hot exhaust pipe provided on the cooling transmission channel.

[0018] Optionally, a soil-turning chamber is provided within the cooling unit.

[0019] Optionally, the cooling unit further includes:

[0020] A cold air unit and an exhaust pipe are connected to the soil turning chamber; the cold air unit is adapted to introduce cold air into the soil turning chamber; the exhaust pipe is adapted to discharge hot air.

[0021] Optionally, it also includes:

[0022] A waste liquid collection unit, a waste liquid transport pipe, and a sewage treatment unit are connected in sequence.

[0023] The waste liquid collection unit is connected to the electro-osmotic dehydration unit; the waste liquid collection unit is suitable for collecting the water removed from the first type of soil.

[0024] Optionally, the preheating unit is provided with an anode soil preheating zone and a cathode soil preheating zone; the anode soil preheating zone is suitable for preheating anode soil; the cathode soil preheating zone is suitable for preheating cathode soil.

[0025] The transmission methods for the anode soil preheating zone and the cathode soil preheating zone are straight-line transmission, curved transmission, or spiral transmission.

[0026] Optionally, a soil-turning structure is provided on both the anode soil preheating zone and the cathode soil preheating zone.

[0027] The technical solution of the present invention has the following advantages compared with the prior art:

[0028] 1. The ex-situ remediation system for water-bearing soil provided by the present invention comprises: a screening unit, adapted to screen the soil to be treated into a first type of soil and a second type of soil; the particle size of the first type of soil is smaller than that of the second type of soil; an electro-osmotic dehydration unit connected to the screening unit; the electro-osmotic dehydration unit is adapted to receive the first type of soil and separate the first type of soil into anodic soil and cathodic soil; a preheating unit connected to the electro-osmotic dehydration unit, the preheating unit being adapted to receive the anodic soil and cathodic soil respectively, and preheat the anodic soil and cathodic soil respectively for dehydration and preliminary removal of organic matter; an ex-situ thermal desorption unit connected to the preheating unit, wherein a rotary kiln is provided in the ex-situ thermal desorption unit; the ex-situ thermal desorption unit is adapted to receive the preheated anodic soil and cathodic soil respectively, and perform ex-situ thermal desorption on the anodic soil and cathodic soil respectively to remove organic matter; and a cooling unit connected to the ex-situ thermal desorption unit. The cooling unit is adapted to receive anolyte and catholyte soil after ex-situ thermal desorption and cool them separately. A rinsing unit is connected to both the cooling unit and the screening unit. The rinsing unit is divided into an anolyte rinsing unit and a catholyte rinsing unit. The anolyte rinsing unit is adapted to receive cooled anolyte soil and rinsing it to remove heavy metals. The catholyte rinsing unit is adapted to receive cooled catholyte soil and second-type soil and rinsing it to remove heavy metals. A first concentration of rinsing solution is sprayed in the anolyte rinsing unit. A second concentration of rinsing solution is sprayed in the catholyte rinsing unit. The first concentration is less than the second concentration. This application adopts the above technical solution, coupling electroosmotic dehydration technology, ex-situ thermal desorption technology, and chemical rinsing technology to achieve efficient removal of organic matter and heavy metals. Furthermore, there is no limitation on the moisture content of the soil to be treated. During the ex-situ thermal desorption process, no agents such as calcium oxide need to be added, which can effectively reduce costs and prevent scaling. Furthermore, the soil is divided into Class I and Class II soils. During the electro-osmotic dehydration process of Class I soil, heavy metal ions (especially cadmium ions) move directionally from the anode to the cathode, so they are mainly found in the cathode soil, while the heavy metal content in the anode soil is lower. That is, Class I soil is divided into anode soil and cathode soil, and different leaching schemes are formulated for soils with different degrees of heavy metal pollution. Different concentrations of leaching solution are used. This can improve the soil remediation effect, achieve automation and save costs.

[0029] 2. The preheating unit of the present invention is connected to the rotary kiln through a waste heat collection unit; the waste heat collection unit is adapted to collect waste heat in the rotary kiln and then supply it to the preheating unit; the present application adopts the above technical solution to make full use of the waste heat from off-site thermal desorption in the rotary kiln and apply it to the preheating unit, thereby saving energy and reducing costs.

[0030] 3. The present invention provides an extraction unit on the rotary kiln; the extraction unit is adapted to extract gas and organic pollutants from the rotary kiln; the extraction unit is connected to a waste gas treatment unit; the waste gas treatment unit is adapted to filter dust and organic pollutants; the waste gas treatment unit delivers the treated gas to the rotary kiln through an air supply unit; the present application adopts the above technical solution, using the extraction unit to extract gas to remove organic pollutants and realize the recycling of gas.

[0031] 4. The present invention includes a soil transport channel in the electro-osmotic dehydration unit; the waste heat of the preheating unit is transported to the soil transport channel; an exhaust pipe is provided on the preheating unit, and the exhaust pipe is connected to the waste gas treatment unit; the exhaust pipe is adapted to form a negative pressure to extract water vapor and organic matter in the preheating unit and the soil transport channel; the present application adopts the above technical solution, making full use of the waste heat of the preheating unit to heat the soil on the soil transport channel, saving energy and reducing costs; and the negative pressure formed by the exhaust pipe prevents organic matter from spreading from the soil transport channel into the atmosphere and polluting the environment.

[0032] 5. The rotary kiln of the present invention is connected to a cooling unit through a cooling transmission channel; the cooling unit includes a hot exhaust pipe provided on the cooling transmission channel; the present application adopts the above technical solution, and further exhausts hot air through the hot exhaust pipe to reduce the soil temperature.

[0033] 6. The present invention provides a soil turning chamber within the cooling unit; this application adopts the above-mentioned technical solution to promote soil cooling by turning the soil.

[0034] 7. The cooling unit of the present invention further includes: a cold air unit and an exhaust pipe connected to the soil turning chamber; the cold air unit is adapted to introduce cold air into the soil turning chamber; the exhaust pipe is adapted to discharge hot air; the present application adopts the above technical solution to promote the cooling process through the cold air unit; the hot air in the soil is then discharged through the exhaust pipe.

[0035] 8. The ex-situ remediation system for water-bearing soil provided by the present invention further includes: a waste liquid collection unit, a waste liquid transport pipe, and a sewage treatment unit connected in sequence; the waste liquid collection unit is connected to an electro-osmotic dehydration unit; the waste liquid collection unit is adapted to collect the water removed from the first type of soil; the present application adopts the above technical solution to reasonably treat the removed water and prevent environmental pollution.

[0036] 9. The present invention provides an anode soil preheating zone and a cathode soil preheating zone within the preheating unit; the anode soil preheating zone is suitable for preheating anode soil; the cathode soil preheating zone is suitable for preheating cathode soil; the transmission forms of the anode soil preheating zone and the cathode soil preheating zone are linear transmission, curved transmission, or spiral transmission; the present application adopts the above technical solution to maximize the preheating of soil through various forms of anode soil preheating zones and cathode soil preheating zones.

[0037] 10. The present invention provides a soil turning structure on both the anode soil preheating zone and the cathode soil preheating zone; the present application adopts the above technical solution to improve the effect of soil preheating by turning the soil. Attached Figure Description

[0038] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0039] Figure 1 This is a schematic diagram of the main layout structure of the ex-situ remediation system for water-bearing soil provided in an embodiment of the present invention;

[0040] Figure 2 This is a top view of the layout structure of the ex-situ remediation system for water-bearing soil provided in an embodiment of the present invention.

[0041] Explanation of reference numerals in the attached figures:

[0042] 1. Screening unit; 2. First conveying channel; 3. Feeder; 4. First feeding port; 5. Second feeding port; 6. Electroosmotic dewatering unit; 7. Soil conveying channel; 8. Anode track; 9. Cathode track; 10. Anode-cathode soil separation zone; 11. Cathode connecting zone; 12. Anode connecting zone; 13. Exhaust pipe; 14. First exhaust pump; 15. Waste gas treatment unit; 16. Preheating unit; 17. Anode soil preheating zone; 18. Cathode soil preheating zone; 19. Heater; 20. 21. Heat pipe; 22. Waste heat collection unit; 23. Anode waste heat collection unit; 24. Cathode waste heat collection unit; 25. Rotary kiln; 26. Anode soil rotary kiln; 27. Cathode soil rotary kiln; 28. Evacuation unit; 29. ​​Anode extraction unit; 30. Cathode extraction unit; 31. Second extraction pump; 32. Ex-situ thermal desorption unit; 33. Anode soil ex-situ thermal desorption unit; 34. Cathode soil ex-situ thermal desorption unit; 35. Gas pipeline; 36. Combustion head; 37. Cooling 37. Anode soil cooling transmission channel; 38. Cathode soil cooling transmission channel; 39. Hot exhaust duct; 40. Anode soil hot exhaust duct; 41. Cathode soil hot exhaust duct; 42. Cooling unit; 43. Cold air unit; 44. Anode cold air unit; 45. Cathode cold air unit; 46. Turning chamber; 47. Anode soil turning chamber; 48. Cathode soil turning chamber; 49. Exhaust duct; 50. Anode exhaust duct; 51. Cathode exhaust duct; 52. Washing transmission channel; 53. 54. Anode soil rinsing and transfer channel; 55. Cathode soil rinsing and transfer channel; 56. Rinsing unit; 57. Anode soil rinsing unit; 58. Cathode soil rinsing unit; 59. Soil outlet; 60. Anode soil outlet; 61. Cathode soil outlet; 62. Second transport channel; 63. Feeder; 64. Anode soil feeder; 65. Cathode soil feeder; 66. Air supply unit; 67. Anode air supply unit; 68. Cathode air supply unit; 69. Waste liquid collection unit; 60. Waste liquid transport pipe. Detailed Implementation

[0043] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0044] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0045] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0046] Furthermore, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0047] like Figures 1 to 2 One specific embodiment of the water-bearing soil ex-situ remediation system shown includes: a screening unit 1, a feeding machine 3, an electro-osmotic dehydration unit 6, a preheating unit 16, a feeder 62, an ex-situ thermal desorption unit 31, a cooling unit 42, and a rinsing unit 55 connected in sequence, as well as a waste liquid collection unit 68, a waste liquid transport pipe 69, and a sewage treatment unit connected in sequence.

[0048] like Figure 1As shown, the screening unit 1 is adapted to screen the soil to be treated into a first type of soil and a second type of soil; specifically, the soil to be treated can be soil with a moisture content higher than 20%, that is, it can be sludge, especially contaminated soil containing organic matter and heavy metal cadmium; the screening unit 1 can be a screening machine. The particle size of the first type of soil is smaller than that of the second type of soil; the particle size of the first type of soil is not greater than 2 mm, and the particle size of the second type of soil is greater than 2 mm. The first type of soil is transported to the feeding machine 3 through the first transport channel 2. The electro-osmotic dewatering unit 6 is adapted to receive the first type of soil and separate the first type of soil into anodic soil and cathodic soil; the preheating unit 16 is adapted to receive the anodic soil and cathodic soil respectively, and preheat the anodic soil and cathodic soil respectively, to dehydrate and initially remove organic matter; a rotary kiln 24 is provided in the ex-situ thermal desorption unit 31; the ex-situ thermal desorption unit 31 is adapted to receive the preheated anodic soil and cathodic soil respectively, and perform ex-situ thermal desorption on the anodic soil and cathodic soil respectively to remove organic matter; specifically, as Figure 2 As shown, the ex-situ thermal desorption unit 31 is divided into an anodic soil ex-situ thermal desorption unit 32 and a cathodic soil ex-situ thermal desorption unit 33, used to perform ex-situ thermal desorption on the anodic soil and cathodic soil respectively. Ex-situ thermal desorption can selectively promote the gasification and volatilization of pollutants by controlling the temperature and the residence time of the material, and has the characteristics of high pollutant removal rate, short processing time and strong versatility, especially for the treatment of soil with high organic content. The cooling unit 42 is adapted to receive the anodic soil and cathodic soil after ex-situ thermal desorption respectively, and cool the anodic soil and cathodic soil respectively; the rinsing unit 55 is also connected to the screening unit 1; specifically, the second type of soil is transported to the rinsing unit 55 through the second transport channel 61. Figure 2 As shown, the leaching unit 55 is divided into an anodic soil leaching unit 56 and a cathodic soil leaching unit 57. The anodic soil leaching unit 56 is adapted to receive cooled anodic soil and leach it to remove heavy metals, specifically cadmium. The cathodic soil leaching unit 57 is adapted to receive cooled cathodic soil and second-class soil and leach it to remove heavy metals, specifically cadmium. Figure 2As shown, the anodic soil leaching unit 56 is connected to the cooling unit 42 via the anodic soil leaching transmission channel 53; the cathodic soil leaching unit 57 is connected to the cooling unit 42 via the cathodic soil leaching transmission channel 54; both the anodic soil leaching transmission channel 53 and the cathodic soil leaching transmission channel 54 are leaching transmission channels 52. A first concentration of leaching solution is sprayed into the anodic soil leaching unit 56; a second concentration of leaching solution is sprayed into the cathodic soil leaching unit 57; the first concentration is less than the second concentration. The leaching method does not damage the soil structure and has a high heavy metal removal rate. The anodic soil leaching unit 56 is provided with an anodic soil outlet 59, and the cathodic soil leaching unit 57 is provided with a cathodic soil outlet 60; both the anodic soil outlet 59 and the cathodic soil outlet 60 are soil outlets 58.

[0049] like Figure 1 As shown, the preheating unit 16 is connected to the rotary kiln 24 via a waste heat collection unit 21; the waste heat collection unit 21 is adapted to collect waste heat from the rotary kiln 24 and then supply it to the preheating unit 16. Specifically, as... Figure 2 As shown, the rotary kiln 24 is divided into an anode soil rotary kiln 25 and a cathode soil rotary kiln 26, used to process anode soil and cathode soil respectively. The waste heat collection unit 21 is divided into an anode waste heat collection unit 22 and a cathode waste heat collection unit 23, used to collect waste heat from the anode soil rotary kiln 25 and the cathode soil rotary kiln 26 respectively. An extraction unit 27 is provided on the rotary kiln 24; the extraction unit 27 is suitable for extracting gases and organic pollutants from the rotary kiln 24; specifically, as shown... Figure 2 As shown, the extraction unit 27 is divided into an anode extraction unit 28 and a cathode extraction unit 29, which are respectively installed on the anode rotary kiln 25 and the cathode rotary kiln 26. The extraction unit 27 is connected to a waste gas treatment unit 15; the waste gas treatment unit 15 is suitable for filtering dust and organic pollutants; the waste gas treatment unit 15 transports the treated gas to the rotary kiln 24 through an air supply unit 65; specifically, as... Figure 2As shown, the air supply unit 65 is divided into an anode air supply unit 66 and a cathode air supply unit 67; the waste gas treatment unit 15 transports the treated gas to the anode soil rotary kiln 25 through the anode air supply unit 66; the waste gas treatment unit 15 transports the treated gas to the cathode soil rotary kiln 26 through the cathode air supply unit 67. A soil transport channel 7 is provided in the electro-osmotic dehydration unit 6; the waste heat of the preheating unit 16 is transported to the soil transport channel 7; an exhaust pipe 13 is provided on the preheating unit 16, and the exhaust pipe 13 is connected to the waste gas treatment unit 15; a first exhaust pump 14 is provided on the exhaust pipe 13 to create a negative pressure to extract water vapor and organic matter from the preheating unit 16 and the soil transport channel 7. The rotary kiln 24 is connected to the cooling unit 42 through a cooling transmission channel 36; the cooling unit 42 includes a hot exhaust pipe 39 provided on the cooling transmission channel 36. Specifically, as shown... Figure 2 As shown, the cooling transmission channel 36 is divided into an anode soil cooling transmission channel 37 and a cathode soil cooling transmission channel 38, used for transporting anode soil and cathode soil respectively. An anode soil hot exhaust pipe 40 and a cathode soil hot exhaust pipe 41 are respectively installed on the anode soil cooling transmission channel 37 and the cathode soil cooling transmission channel 38. The hot exhaust pipe 39 is also divided into an anode soil hot exhaust pipe 40 and a cathode soil hot exhaust pipe 41. The cooling unit 42 is equipped with a soil turning chamber 46. The cooling unit 42 further includes a cold air unit 43 and an exhaust pipe 49 connected to the soil turning chamber 46; the cold air unit 43 is adapted to introduce cold air into the soil turning chamber 46; the exhaust pipe 49 is adapted to discharge hot air. Specifically, as... Figure 2As shown, the soil turning chamber 46 is divided into an anode soil turning chamber 47 and a cathode soil turning chamber 48; the anode soil turning chamber 47 is connected to an anode cold air unit 44 and an anode exhaust pipe 50; the cathode soil turning chamber 48 is connected to a cathode cold air unit 45 and a cathode exhaust pipe 51. That is, the cold air unit 43 is divided into an anode cold air unit 44 and a cathode cold air unit 45; the exhaust pipe 49 is divided into an anode exhaust pipe 50 and a cathode exhaust pipe 51. The waste liquid collection unit 68 is connected to the electro-osmotic dehydration unit 6; the waste liquid collection unit 68 is suitable for collecting the water removed from the first type of soil. The preheating unit 16 is equipped with an anode soil preheating zone 17 and a cathode soil preheating zone 18; the anode soil preheating zone 17 is suitable for preheating anode soil; the cathode soil preheating zone 18 is suitable for preheating cathode soil; the transmission methods of the anode soil preheating zone 17 and the cathode soil preheating zone 18 are linear transmission, curved transmission, or spiral transmission, etc. Furthermore, both the anode soil preheating zone 17 and the cathode soil preheating zone 18 are equipped with soil turning structures. The feeder 3 is suitable for conveying the first type of soil to the electro-osmotic dewatering unit 6; the feeder 3 is equipped with a first feed port 4 and a second feed port 5; the electro-osmotic dewatering unit 6 is equipped with an anode-cathode soil separation belt 10, an anode track 8, and a cathode track 9; the anode-cathode soil separation belt 10, the anode track 8, and the cathode track 9 together form a soil transport channel 7. The first type of soil is laid on the anode-cathode soil separation belt 10 and the cathode track 9 through the first feed port 4 and the second feed port 5 respectively. Direct current is applied to the anode track 8 and the cathode track 9; the conveying speed of the anode-cathode soil separation belt 10, the anode track 8, and the cathode track 9 are all the same; the electro-osmotic dewatering time of the electro-osmotic dewatering unit 6 is not less than 15 minutes. The feeder 62 is suitable for conveying preheated anode soil and cathode soil to the rotary kiln 24 respectively; specifically, as shown in the figure Figure 2 As shown, the feeder 62 is divided into an anode soil feeder 63 and a cathode soil feeder 64. The anode soil feeder 63 is suitable for feeding preheated anode soil into the anode soil rotary kiln 25; the cathode soil feeder 64 is suitable for feeding preheated cathode soil into the cathode soil rotary kiln 26. The waste heat collection unit 21 is connected to the heater 19 in the preheating unit 16 via a heat pipe 20. The ex-situ thermal desorption unit 31 includes a gas pipeline 34 and a burner head 35 connected together; the burner head 35 is suitable for supplying heat to the rotary kiln 24.

[0050] The main operating process of the ex-situ remediation system for water-bearing soil described in this application after separation into anodic and cathodic soils is briefly described below:

[0051] like Figure 1 and Figure 2As shown, the anode soil first passes through the anode connecting belt 12 and the anode soil preheating belt 17; then it enters the anode soil rotary kiln 25 through the anode soil feeder 63, and then enters the anode soil ex-situ thermal desorption unit 32; the anode soil rotary kiln 25 rotates at a certain speed to ensure that the anode soil is fully heated. Gas is transported from the gas pipeline 34 to the burner head 35 to heat the anode soil rotary kiln 25. An anode extraction unit 28 is installed above the anode soil rotary kiln 25, and a second extraction pump 30 is installed on the anode extraction unit 28 to extract air to remove organic pollutants. The gas is drawn into the waste gas treatment unit 15, where it undergoes multiple treatments to filter dust and organic pollutants, and then is sent back into the anode soil rotary kiln 25 by the anode air supply unit 66, realizing the recycling of the gas. After the ex-situ thermal desorption treatment, the anode soil passes through the anode soil cooling transmission channel 37, in which an anode soil hot exhaust pipe 40 is installed to further exhaust hot air and reduce the soil temperature. The anode soil is then transported to the anode soil turning chamber 47 within the cooling unit 42, where turning promotes soil cooling. The anode soil turning chamber 47 is equipped with an anode cold air unit 44 to further accelerate the cooling process. Hot air from the soil is exhausted through the anode exhaust pipe 50. The cooled anode soil enters the anode soil rinsing unit 56 through the anode soil rinsing transport channel 53. Because cadmium ions move directionally from the anode to the cathode during electroosmotic dehydration, they are mainly present in the cathode soil, resulting in a lower cadmium content in the anode soil. Therefore, the rinsing solution concentration in the anode soil rinsing unit 56 is low. The cleaned soil after rinsing is discharged through the anode soil outlet 59.

[0052] The cathode soil first passes through the cathode connecting belt 11 and the cathode soil preheating belt 18; then it enters the cathode soil rotary kiln 26 via the cathode soil feeder 64, and further enters the cathode soil ex-situ thermal desorption unit 33; the cathode soil rotary kiln 26 rotates at a certain speed to ensure that the anode soil is fully heated. Gas is transported from the gas pipeline 34 to the burner head 35 to heat the cathode soil rotary kiln 26. A cathode extraction unit 29 is located above the cathode soil rotary kiln 26, and a second extraction pump 30 also extracts gas from the cathode extraction unit 29 to remove organic pollutants. The gas is drawn into the waste gas treatment unit 15, where it undergoes multiple treatments to filter dust and organic pollutants, and is then sent back into the cathode soil rotary kiln 26 by the cathode air supply unit 67, achieving gas recycling. After ex-situ thermal desorption treatment, the cathode soil passes through the cathode soil cooling transmission channel 38, which is equipped with a cathode soil hot exhaust pipe 41 to further exhaust hot air and reduce the soil temperature. Then, the cathodic soil is transported to the cathodic soil turning chamber 48 within the cooling unit 42, where turning promotes soil cooling. The cathodic soil turning chamber 48 is equipped with a cathodic cold air unit 45 to facilitate the cooling process. Hot air from the soil is discharged through the cathodic exhaust pipe 51. The cooled cathodic soil enters the cathodic soil rinsing unit 57 through the cathodic soil rinsing transport channel 54. Because cadmium ions move directionally from the anode to the cathode during electroosmotic dehydration, they are mainly present in the cathodic soil, while the cadmium content in the anode soil is lower. Therefore, the rinsing solution concentration in the cathodic soil rinsing unit 57 is higher. Second-class soil is also sent to the cathodic soil rinsing unit 57 for rinsing. The cleaned soil after rinsing is discharged through the cathodic soil outlet 60.

[0053] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. An ex-situ remediation system for water-bearing soil, characterized in that, include: The screening unit (1) is adapted to screen the soil to be treated into a first type of soil and a second type of soil; the particle size of the first type of soil is smaller than that of the second type of soil. An electro-osmotic dehydration unit (6) is connected to a screening unit (1); the electro-osmotic dehydration unit (6) is adapted to receive a first type of soil and separate the first type of soil into anodic soil and cathodic soil; The preheating unit (16) is connected to the electroosmotic dehydration unit (6). The preheating unit (16) is adapted to receive anodic soil and cathodic soil respectively, and preheat the anodic soil and cathodic soil respectively to dehydrate and initially remove organic matter. An ex-situ thermal desorption unit (31) is connected to a preheating unit (16), and a rotary kiln (24) is provided in the ex-situ thermal desorption unit (31); the ex-situ thermal desorption unit (31) is adapted to receive preheated anode soil and cathode soil respectively, and to perform ex-situ thermal desorption on the anode soil and cathode soil respectively to remove organic matter; A cooling unit (42) is connected to an ex-situ thermal desorption unit (31); the cooling unit (42) is adapted to receive the anodic soil and cathodic soil after ex-situ thermal desorption respectively, and to cool the anodic soil and cathodic soil respectively; The rinsing unit (55) is connected to both the cooling unit (42) and the screening unit (1); the rinsing unit (55) is divided into an anode soil rinsing unit (56) and a cathode soil rinsing unit (57); the anode soil rinsing unit (56) is adapted to receive cooled anode soil and rinse the anode soil to remove heavy metals; the cathode soil rinsing unit (57) is adapted to receive cooled cathode soil and second-class soil and rinse the cathode soil and second-class soil to remove heavy metals; a first concentration of rinsing solution is sprayed in the anode soil rinsing unit (56); a second concentration of rinsing solution is sprayed in the cathode soil rinsing unit (57); the first concentration is less than the second concentration. The preheating unit (16) is provided with an anode soil preheating zone (17) and a cathode soil preheating zone (18); the anode soil preheating zone (17) is suitable for preheating anode soil; the cathode soil preheating zone (18) is suitable for preheating cathode soil. The transmission methods of the anode soil preheating zone (17) and the cathode soil preheating zone (18) are either straight-line transmission or curved transmission; Both the anode soil preheating zone (17) and the cathode soil preheating zone (18) are equipped with soil turning structures; The particle size of the first type of soil is no greater than 2 mm, and the particle size of the second type of soil is greater than 2 mm.

2. The ex-situ remediation system for water-bearing soil according to claim 1, characterized in that, The preheating unit (16) is connected to the rotary kiln (24) through the waste heat collection unit (21); the waste heat collection unit (21) is adapted to collect the waste heat in the rotary kiln (24) and then supply it to the preheating unit (16).

3. The ex-situ remediation system for water-bearing soil according to claim 1, characterized in that, An extraction unit (27) is provided on the rotary kiln (24); the extraction unit (27) is adapted to extract gases and organic pollutants from the rotary kiln (24); The extraction unit (27) is connected to the exhaust gas treatment unit (15); the exhaust gas treatment unit (15) is suitable for filtering dust and organic pollutants; The waste gas treatment unit (15) delivers the treated gas to the rotary kiln (24) through the air supply unit (65).

4. The ex-situ remediation system for water-bearing soil according to claim 3, characterized in that, The electro-osmotic dehydration unit (6) is provided with a soil transport channel (7); the waste heat of the preheating unit (16) is transported to the soil transport channel (7); the preheating unit (16) is provided with an exhaust pipe (13), which is connected to the waste gas treatment unit (15); the exhaust pipe (13) is adapted to form a negative pressure to extract water vapor and organic matter in the preheating unit (16) and the soil transport channel (7).

5. The ex-situ remediation system for water-bearing soil according to claim 1, characterized in that, The rotary kiln (24) is connected to the cooling unit (42) through the cooling transmission channel (36); the cooling unit (42) includes a hot exhaust pipe (39) provided on the cooling transmission channel (36).

6. The ex-situ remediation system for water-bearing soil according to any one of claims 1-5, characterized in that, A soil turning chamber (46) is provided inside the cooling unit (42).

7. The ex-situ remediation system for water-bearing soil according to claim 6, characterized in that, The cooling unit (42) further includes: A cold air unit (43) and an exhaust pipe (49) are connected to the soil turning chamber (46); the cold air unit (43) is adapted to introduce cold air into the soil turning chamber (46); the exhaust pipe (49) is adapted to discharge hot air.

8. The ex-situ remediation system for water-bearing soil according to any one of claims 1-5, characterized in that, Also includes: Waste liquid collection unit (68), waste liquid transport pipe (69) and sewage treatment unit are connected in sequence; The waste liquid collection unit (68) is connected to the electro-osmotic dehydration unit (6); the waste liquid collection unit (68) is adapted to collect the water removed from the first type of soil.

Images