Soil remediation method for improving utilization efficiency of soil remediation liquid

Abstract

The invention discloses a contaminated soil remediation method for improving the utilization efficiency of soil remediation liquid in the field of heavy metal contaminated soil remediation, and the method comprises the following steps: selecting a circular remediation area with the largest area on soil to be remediated, digging a spirally outward ditch from the central point of the selected remediation area, arranging a gabion net frame in the ditch, and carrying out soil remediation on the gabion net frame; the gabion net frame is filled with a permeable layer, a conveying pipeline is arranged at the top of the permeable layer, and liquid outlet holes are evenly distributed in the conveying pipeline; remediation liquid in the liquid conveying pipeline flows out of the liquid outlet holes, enters the permeation layer and permeates out of the gabion net frame through the permeation layer to enter soil. The top of the gabion net frame is provided with a sliding rail, a rotary cultivator is arranged between every two adjacent sliding rails between every two adjacent circles of ditches and used for turning over soil between the ditches, in the scheme, application of the remediation liquid into the heavy metal contaminated soil and turning over of the contaminated soil do not interfere with each other, and therefore the operation can be synchronously conducted.

Description

Technical Field

[0001] The present invention belongs to the field of soil remediation, and particularly relates to a soil remediation method for improving the utilization efficiency of soil remediation liquid. Background Art

[0002] Soil is originally a natural shelter and purification treatment site for various waste materials. When the accumulation of various heavy metal pollutants in the soil is excessive and affects and exceeds the self-purification ability of the soil, the polluted soil needs to be remediated.

[0003] In the prior art, the principle of soil remediation adopted is to apply remediation liquid for remediation. When implementing such technology, the remediation liquid spraying and infiltration methods are usually adopted, and there are also other advantages. For example, a contaminated soil remediation device with the publication number CN110814009B adopts the infiltration method of remediation liquid. The device includes a number of liquid infiltration cylinders with a hollow middle part. The outer wall of the liquid infiltration cylinder is provided with liquid infiltration holes distributed in an array. An adsorbed sponge wrapped is placed inside the liquid infiltration cylinder; an array of liquid passing hoses is fixedly installed inside the adsorbed sponge. The liquid passing hoses are provided with liquid passing holes distributed in an array, and the liquid passing hoses extend to the outside of the liquid infiltration cylinder; compared with the existing spraying type, continuous remediation of contaminated soil is realized through the sponge infiltration type; at the same time, the utilization rate of the remediation liquid can be improved through the sponge infiltration type, and at the same time, the volatilization of the remediation liquid during the remediation process is also reduced.

[0004] Another example is a soil remediation system and a soil remediation method with the publication number CN114309039B. The soil remediation system includes: a heating unit; an injection and extraction unit, where the injection and extraction unit includes an injection unit and an extraction unit. The injection unit includes a number of injection well pipes, and the injection well pipes include a number of injection hard well pipes and a number of injection soft well pipes, and the injection hard well pipes are connected to the injection soft well pipes; the extraction unit includes a number of extraction well pipes, and the extraction well pipes include a number of extraction hard well pipes and a number of extraction soft well pipes, and the extraction hard well pipes are connected to the extraction soft well pipes; a treatment unit. Since the injection soft well pipes and the extraction soft well pipes are deformable and adjustable, the curvature radius of the pipe pulling construction of the well pipes can be reduced, the construction working surface can be reduced, the drilling running meters can be reduced, the well pipe consumables can be reduced, the cost can be reduced, and it can adapt to the required soil-entering arc channel and soil-exiting arc channel when the drilling rig is placed on the ground surface without placing the drilling rig in the polluted soil to reduce the construction procedures.

[0005] After adding the remediation liquid to the polluted soil, it is best to use machinery such as a rotary tiller to deeply plow and mix the polluted soil to make the remediation liquid more evenly distributed in the soil. However, the obvious disadvantage of using the buried pipeline method is that it is not convenient to deeply plow or turn over the soil. And the spraying type also has obvious disadvantages, that is, it cannot continuously provide the remediation liquid, and the remediation liquid is easily volatilized during the remediation process. Summary of the Invention

[0006] The present invention aims to provide a soil remediation method for improving the utilization efficiency of a soil remediation liquid, achieving the purpose of facilitating deep plowing and continuously providing the remediation liquid, so as to solve the deficiencies existing in the prior art.

[0007] A soil remediation method for improving the utilization efficiency of a soil remediation liquid in this solution includes the following steps:

[0008] Step 1, Digging ditches: Select a circular remediation area with the largest area on the soil to be remediated, and dig a spiral-outward ditch with the center point of the selected remediation area as the center. The distance between adjacent two circles of ditches is 100 - 150 cm;

[0009] Step 2, Pipe laying: Lay gabion boxes in the ditches. The gabion boxes are filled with a permeable layer. A conveying pipeline is arranged on the top of the permeable layer. Liquid outlet holes are evenly distributed on the conveying pipeline. Storage barrels are connected to the conveying pipeline at intervals. An electric control valve is arranged on the storage barrel, and a remediation liquid is contained in the storage barrel;

[0010] Step 3, Conveying the remediation liquid: After the electric control valve is opened, the remediation liquid in the storage barrel flows along the liquid conveying pipeline. The remediation liquid in the liquid conveying pipeline flows out through the liquid outlet holes and enters the permeable layer, and then penetrates into the soil outside the gabion box through the permeable layer;

[0011] Step 4, Deep plowing: Slide rails are arranged on the top of the gabion box. A rotary tiller is arranged between adjacent slide rails between adjacent two circles of ditches for plowing the soil between the ditches; The rotary tiller includes a bottom plate. Pulleys that roll on the slide rails are arranged on both sides of the bottom plate. A rotary tillage shaft is also connected to the bottom plate. Rotary tillage plows are arranged on the rotary tillage shaft. A driving mechanism for driving the pulleys to rotate is arranged on the bottom plate; The soil is plowed as the rotary tiller moves on the slide rails.

[0012] The beneficial technical effects of the present invention are:

[0013] 1. The way of digging ditches in Step 1 makes the ditches evenly distributed in the soil to be remediated, increasing the distribution of the remediation liquid in the ditches in the soil and increasing the remediation area.

[0014] 2. Pipes are laid in the ditches. The gabion box is used to separate the permeable layer from the polluted soil. On the one hand, it is beneficial for the remediation liquid to continuously and evenly penetrate into the polluted soil in the permeable layer. All the remediation liquid entering the permeable layer can finally smoothly penetrate into the polluted soil. The storage barrels arranged at intervals ensure that the polluted soil per unit area can contact the remediation liquid as evenly as possible. The electric control valve centrally controls or separately controls the remediation liquid in the storage barrel to enter the conveying pipeline, which is convenient for management and operation.

[0015] 3. Design a rotary tiller for use in conjunction with gabion boxes, i.e., the top of the gabion box is exposed outside the contaminated soil, and the rotary tiller moves spirally along the outer wall of adjacent gabion boxes. The driving mechanism drives the pulley to slide on the slide rail of the gabion box, so that during the movement of the entire rotary tiller, the plow is inserted into the soil to loosen and turn over the soil. After the soil at different depths is turned up, it is more evenly mixed after multiple plowings, and the remediation liquid infiltrated into the soil can also be more evenly distributed in the contaminated soil.

[0016] 4. Gabion boxes of appropriate size can be used. First, fill them with materials for the infiltration layer, and then distribute the gabion boxes one by one in the ditch. In this way, when the remediation of the contaminated soil is completed, the gabion boxes can be taken out as a whole, thus realizing the removal of the infiltration layer from the ditch together. The construction is very convenient, and the gabion boxes can be reused.

[0017] In summary, in this solution, applying the remediation liquid to the contaminated soil and plowing the contaminated soil do not interfere with each other, so they can be carried out synchronously. Moreover, the remediation liquid can be continuously provided to the contaminated soil or the seepage time of the remediation liquid can be controlled as needed. And the remediation liquid enters the soil through the infiltration method, reducing the volatilization of the remediation liquid, improving the utilization rate of the remediation liquid, and reducing resource waste.

[0018] Further, the infiltration layer includes several layers of liquid guiding frames. Each liquid guiding frame consists of two liquid guiding plates connected in a "V" shape. The liquid guiding plates are evenly distributed with infiltration holes, and the ends of the liquid guiding plates are in contact with the wall of the gabion box. The liquid guiding plates connected in a "V" shape divert the remediation liquid to the two side gabion boxes. At the same time, part of the remediation liquid penetrates downward along the infiltration holes, so that the remediation liquid penetrates more evenly to the two sides and downward.

[0019] Further, gravel is evenly distributed on the liquid guiding frames, and the particle size of the gravel on the liquid guiding frames from top to bottom gradually decreases. Gravel can help the infiltration of the remediation liquid and the cost is relatively low. Moreover, compared with materials such as sponges, gravel can reduce the absorption of the remediation liquid, thus further improving the utilization rate of the remediation liquid.

[0020] Further, the inclination angle of the liquid guiding plate is 15° - 25°. This can prevent the rapid flow of the remediation liquid.

[0021] Further, a high-pressure pump is provided at the connection between the conveying pipeline and the liquid storage barrel. This can increase the flow rate of the remediation liquid in the infusion pipeline, which helps the remediation liquid to be evenly distributed in the infusion pipeline and penetrate out from the liquid outlet holes. If the flow rate of the remediation liquid in the infusion pipeline is too slow, it is not conducive to the discharge amount of the remediation liquid from each liquid outlet hole to reach a relatively uniform state.

[0022] Further, a geotextile infiltration layer is provided between the gabion box and the ditch wall to prevent the soil wetted by the remediation liquid from clogging the gabion box.

[0023] Furthermore, an air suction pipe is provided on the wall of the gabion frame, and the air suction pipe is connected to an exhaust gas treatment device. The harmful gas generated by the harmful substances in the polluted soil under the biological action is regularly sucked through the air suction pipe to reduce the discharge of harmful gas into the air. The air suction pipe is connected to the exhaust gas treatment device after passing through the gabion frame. The exhaust gas treatment device is a commonly used device for treating harmful gas at present, and the technology is mature and easy to implement. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 FIG. 1 is a top view of a ditch in Example 1 of a soil remediation method for improving the utilization efficiency of a soil remediation liquid according to the present invention;

[0025] Figure 2 FIG. 2 is a longitudinal sectional view after a ditch is excavated and pipes are arranged in the soil in Example 1;

[0026] Figure 3 FIG. 3 is a longitudinal sectional view after a ditch is excavated and pipes are arranged in the soil in Example 2. DETAILED DESCRIPTION OF THE INVENTION

[0027] The following is a further detailed description through specific embodiments:

[0028] The reference numerals in the accompanying drawings of the specification include: ditch 1, rotary tiller 2, bottom plate 21, transmission rod 22, motor 23, driving bevel gear 24, driven bevel gear 25, pulley 26, rotary tillage shaft 27, skid plow 28, liquid storage barrel 3, soil 4, gabion frame 5, liquid guide plate 6, gravel 7, conveying pipe 8, connecting block 9, connecting rod 10, slide rail 11, air suction pipe 12, geotextile permeable layer 13.

[0029] Example 1 is basically as shown in the Figure 1 and Figure 2 figures: A soil remediation method for improving the utilization efficiency of a soil remediation liquid includes the following steps:

[0030] Step 1, excavating a ditch 1: Select a circular remediation area with the largest area on the soil to be remediated, and excavate a spiral outward ditch 1 with the center point of the selected remediation area as the center. The distance between adjacent two circles of ditches 1 is 100-150 cm, preferably 150 cm;

[0031] Step 2, pipe laying: Arrange a plurality of gabion frames 5 closely in the ditch 1. The gabion frames 5 are filled with a permeable layer. A conveying pipe 8 is arranged on the top of the permeable layer. Liquid outlet holes are evenly distributed on the conveying pipe 8. The conveying pipe 8 is connected to the liquid storage barrel 3 at intervals. A high-pressure pump is provided at the connection between the conveying pipe 8 and the liquid storage barrel 3; an electric control valve is provided on the liquid storage barrel 3, and a remediation liquid is contained in the liquid storage barrel 3. The remediation liquid is a conventional technology, and a suitable remediation liquid is adjusted according to the actual situation of the soil 4;

[0032] The permeable layer includes several liquid guiding frames. Each liquid guiding frame consists of two liquid guiding plates 6 connected in a "V" shape. The inclination angle of the liquid guiding plates 6 ranges from 15° to 25°. The liquid guiding plates 6 are evenly distributed with permeation holes. The ends of the liquid guiding plates 6 are clamped or supported on the wall of the gabion mesh frame 5. The liquid guiding frames are evenly distributed with gravel 7, and the particle size of the gravel 7 on the liquid guiding frames gradually decreases from top to bottom.

[0033] Step 3: Transport the repair liquid: After opening the electric control valve, the repair liquid in the storage barrel 3 flows along the liquid delivery pipeline. The repair liquid in the liquid delivery pipeline flows out through the liquid outlet holes and enters the permeable layer, and then permeates out of the gabion mesh frame 5 into the soil 4 through the permeable layer.

[0034] Step 4: Deep plowing: The top of the gabion mesh frame 5 extends out of the surface layer of the soil 4. The outer wall of the gabion mesh frame 5 is provided with slide rails 11. A rotary tiller 2 is provided between the adjacent slide rails 11 of the adjacent two circles of ditches 1 for plowing the soil 4 between the ditches 1. The rotary tiller 2 includes a bottom plate 21. Two sides of the bottom plate 21 are provided with pulleys 26 that roll on the slide rails 11. The other two sides of the bottom plate 21 are both connected with rotary tilling shafts 27. Rotary tilling plows 28 are provided on the rotary tilling shafts 27. The plows 28 on the two rotary tilling shafts 27 face in opposite directions. A driving mechanism for driving the pulleys 26 to rotate is provided on the bottom plate 21. The driving mechanism includes two motors 23 respectively used to drive the pulleys 26 inside and outside the ditch 1. The output shaft of the motor 23 is connected with a driving bevel gear 24. The driving bevel gear 24 is also rotatably connected to the bottom plate 21 through an "L"-shaped connecting rod 10. The driving bevel gear 24 meshes with a driven bevel gear 25. The driven bevel gear 25 is fixedly connected with a transmission rod 22. One end of the transmission rod 22 is fixedly connected with the pulley 26. The rod body and the other end of the transmission rod 22 are both rotatably connected to the bottom plate 21 through connecting blocks 9. As the rotary tiller 2 moves on the slide rails 11, the soil 4 is plowed.

[0035] Example 2, the difference from Example 1 is as Figure 3 shown. A geotextile permeable layer 13 is provided between the gabion mesh frame 5 and the wall of the ditch 1. An air suction pipeline 12 is provided on the wall of the gabion mesh frame 5. The air suction pipeline 12 is communicated with a tail gas treatment device. The air suction pipeline 12 is located between the geotextile permeable layer 13 and the gabion mesh frame 5.

[0036] Taking Embodiment 2 as an example, the specific implementation process of the present invention is as follows: In this solution, applying the repair liquid to the soil 4 and plowing the soil 4 are independent of each other, so they can be carried out simultaneously, and the repair liquid can be continuously provided to the soil 4 or the seepage time of the repair liquid can be controlled as needed. The motor 23 drives the pulley 26 to slide on the slide rail 11 of the gabion box 5, so that during the movement of the entire rotary tiller 2, the plowshare 28 is inserted into the soil 4 to loosen the soil 4. After the soil 4 at different depths is loosened, it is more evenly mixed after multiple plowings, and the repair liquid infiltrated into the soil 4 can also be more evenly distributed in the soil 4. There are rotary tillage shafts 27 on both sides of the bottom plate 21 of the rotary tiller 2, and the plowshares 28 on the two rotary tillage shafts 27 face in opposite directions. In this way, the forward and reverse rotation of the motor 23 can enable the rotary tiller 2 to plow the soil 4 back, improving the plowing efficiency.

Claims

1. A soil remediation method for improving the utilization efficiency of soil remediation fluid, characterized in that The following steps are involved: Step 1: Dig ditches: Select the largest circular repair area on the soil to be repaired, and dig spiral ditches from the center of the selected repair area. The distance between two adjacent circles of ditches is 100-150cm; Step 2: pipe laying: a Binge mesh frame is arranged in the ditch, the Binge mesh frame is filled with a permeable layer, a delivery pipe is arranged on the top of the permeable layer, liquid outlet holes are evenly distributed on the delivery pipe, liquid storage barrels are connected at intervals on the delivery pipe, an electric control valve is provided on the liquid storage barrel, and the liquid storage barrel is filled with repair liquid; Step 3: Transporting the repair liquid: After the electric control valve is opened, the repair liquid in the liquid storage barrel flows along the liquid delivery pipeline, and the repair liquid in the liquid delivery pipeline flows out through the liquid outlet hole into the permeable layer, and then penetrates into the soil outside the Binger mesh frame through the permeable layer; Step 4, deep plowing: A slide rail is provided on the top of the Binger net frame, and a rotary tiller is provided between adjacent slide rails between two adjacent circles of ditches, which is used to plow the soil between the ditches; the rotary tiller includes a base plate, pulleys rolling on the slide rails are provided on both sides of the base plate, a rotary tiller shaft is also connected to the base plate, a rotary tiller plow is provided on the rotary tiller shaft, and a driving mechanism for driving the pulley to rotate is provided on the base plate; the soil is plowed as the rotary tiller moves on the slide rail.

2. A soil remediation method for improving the utilization efficiency of soil remediation fluid according to claim 1, characterized in that: The permeable layer comprises several layers of liquid guide frames, which are composed of two liquid guide plates connected in a herringbone shape, with permeable holes evenly distributed on the liquid guide plates, and the ends of the liquid guide plates are in contact with the wall of the Binger mesh frame.

3. A soil remediation method for improving the utilization efficiency of soil remediation fluid according to claim 2, characterized in that: The liquid conducting frame is evenly distributed with crushed stones, and the particle size of the crushed stones on the liquid conducting frame decreases gradually from top to bottom.

4. A soil remediation method for improving the utilization efficiency of soil remediation fluid according to claim 3, characterized in that: The inclination angle of the liquid guide plate is 15° to 25°.

5. A soil remediation method for improving the utilization efficiency of soil remediation fluid according to any one of claims 1 to 4, characterized in that: A high-pressure pump is provided at the connection point between the delivery pipeline and the liquid storage barrel.

6. A soil remediation method for improving the utilization efficiency of soil remediation fluid according to any one of claims 1 to 4, characterized in that: A geotextile penetration layer is arranged between the Binge mesh frame and the ditch wall.

7. A soil remediation method for improving the utilization efficiency of soil remediation fluid according to claim 6, characterized in that: An air intake pipe is arranged on the wall of the Binger mesh frame, and the air intake pipe is connected with an exhaust gas treatment device.

Images