Method and device for combined remediation of heavy metal contaminated soil

Abstract

The invention relates to the technical field of soil remediation, and discloses a method and device for combined remediation of heavy metal contaminated soil, and the method for combined remediation of the heavy metal contaminated soil comprises the following steps: S1, soil pretreatment: carrying out sampling analysis on to-be-remediated soil; s2, screening and adding a curing agent: screening a proper curing agent according to the heavy metal pollution type of the soil; s3, microbial inoculation and culture; and S4, process regulation and monitoring: regularly monitoring the pH value, the oxidation-reduction potential and the heavy metal form change index of the soil. Through the steps, the adding amount and action time of the curing agent and the microorganisms can be precisely regulated and controlled, personalized remediation schemes can be formulated according to soil of different pollution degrees and types, precise putting of the curing agent, efficient inoculation of the microorganisms and real-time monitoring of the soil remediation process can be achieved, and the remediation efficiency and quality are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of soil remediation, and in particular to a method and device for combined remediation of heavy metal contaminated soil. Background Art

[0002] With the acceleration of industrialization and urbanization, the problem of heavy metal contamination in soil is becoming increasingly serious. The accumulation of heavy metals in the soil not only harms the soil ecosystem but also endangers human health through the food chain.

[0003] Traditional single methods of heavy metal contaminated soil remediation, such as the simple use of curing agents, can reduce the mobility of heavy metals, but cannot fundamentally reduce the total amount of heavy metals in the soil; and relying solely on microbial remediation has a long cycle and its efficiency is greatly affected by environmental factors, making it difficult to meet the needs of rapid remediation.

[0004] In existing combined repair technologies, there is a problem of mutual interference between curing agents and microorganisms. For example, The addition of some curing agents changes the pH and pore structure of the soil, affecting the activity and growth and reproduction of microorganisms, resulting in unsatisfactory remediation effects.

[0005] The lack of effective methods to precisely control the amount of curing agents and microorganisms added and the duration of action makes it difficult to develop personalized remediation plans for soils of different degrees and types of contamination.

[0006] The relevant remediation devices have a single function and are unable to simultaneously achieve the precise delivery of curing agents, efficient inoculation of microorganisms, and real-time monitoring of the soil remediation process, which restricts the efficiency and quality of remediation.

[0007] In view of this, the present invention proposes a method and apparatus for combined remediation of heavy metal contaminated soil. Summary of the Invention

[0008] In order to make up for the deficiencies of the prior art, at least one technical problem raised in the background technology is solved.

[0009] The present invention provides a method for combined remediation of heavy metal contaminated soil, comprising the following steps: S1. Soil pretreatment: Sampling and analysis of the soil to be repaired to determine the type and content of heavy metals and the physical and chemical properties of the soil. Based on the analysis results, the soil is crushed and screened to pre-treat it in order to improve the subsequent repair effect.

[0010] S2. Screening and Adding Curing Agents: Screen the appropriate curing agent based on the type of heavy metal contamination in the soil. For example, for lead-contaminated soil, a phosphate curing agent can be used. Calculate and determine the amount of curing agent to add. Add the curing agent in layers to ensure thorough mixing with the soil. After addition, use mechanical stirring equipment to evenly distribute the curing agent throughout the soil. S3. Microbial inoculation and cultivation: Select microbial strains with strong tolerance and enrichment capabilities for the target heavy metals, such as cadmium-resistant Bacillus. Mix the cultured microbial solution with the nutrient solution according to the appropriate ratio and inoculate it into the soil treated with the solidifying agent by spraying. Then, a layer of moisturizing and breathable material is covered on the soil surface to create an environment suitable for the growth of microorganisms and promote the colonization and reproduction of microorganisms in the soil; S4. Process control and monitoring: Regularly monitor the soil's pH, redox potential, and heavy metal form change indicators. Based on the monitoring results, control the soil environment by adding acid-base regulators and ventilation to enable the curing agent and microorganisms to achieve the best repair effect.

[0011] By adopting the above technical solution, the amount of curing agent and microorganism added and the action time can be accurately controlled, and personalized remediation plans can be formulated for soils with different degrees of pollution and types. It can also achieve precise delivery of curing agents, efficient inoculation of microorganisms, and real-time monitoring of the soil remediation process, thereby improving remediation efficiency and quality.

[0012] On the other hand, the present application also provides a device for combined remediation of heavy metal contaminated soil, comprising: A soil processing device for mixing soil to which a curing agent is added, the soil processing device comprising a mixing assembly, the mixing assembly comprising a first mobile frame and a mixing drum fixedly mounted on the upper surface of the first mobile frame, the mixing drum having a feed inlet formed on its upper surface and a discharge pipe disposed at its bottom end, the discharge pipe having a discharge valve disposed on its surface; A microbial inoculation device is used to spray a microbial liquid on treated soil. The microbial inoculation device includes a second mobile frame, and a bacterial liquid storage tank and a metering pump respectively fixed to the bottom wall of the second mobile frame. A mounting frame is fixed to the side of the second mobile frame through two mounting plates. A spray pipe is provided inside the mounting frame, and a plurality of atomizing nozzles are equidistantly arranged on the lower surface of the spray pipe.

[0013] By adopting the above technical solution, the curing agent and the soil can be fully mixed, and the soil can be driven to be quickly discharged from the mixing drum, and the microbial liquid can be evenly sprayed on the surface of the soil through the atomizing nozzle. Preferably, the inner top wall of the mixing drum is rotatably provided with a stirring rod extending to the inside of the discharge pipe, and the surface of the stirring rod is symmetrically fixed with two groups of stirring blades, and the ends of the two groups of stirring blades are fixed with scrapers that are slidably connected to the inner wall of the mixing drum, and the surface of the stirring rod is also fixed with spiral conveying blades that are adapted to the inner wall of the discharge pipe.

[0014] By adopting the above technical solution, the soil and curing agent can be fully stirred by the stirring blades driven by the rotation of the stirring rod, and the setting of the spiral conveying blades can flip the bottom soil upward during stirring, and drive the soil to automatically enter the discharge pipe during discharge.

[0015] Preferably, a reduction gear box is fixedly provided on the upper surface of the mixing drum, and the top end of the mixing rod extends to the interior of the reduction gear box. A first motor for driving the mixing rod to rotate at a reduced speed is fixedly provided on the upper surface of the reduction gear box.

[0016] By adopting the above technical solution, the stirring rod can be driven to rotate at a reduced speed by the rotation of the first motor.

[0017] Preferably, the inner wall of the reduction gear box is rotatably provided with a first connecting shaft and a second connecting shaft, the output end of the first motor extends to the interior of the reduction gear box and is fixedly connected to the top end of the first connecting shaft, the surface of the first connecting shaft is fixed with a first small gear, the surface of the second connecting shaft is fixed with a first large gear that meshes with the first small gear, the surface of the stirring rod is fixed with a second large gear, and the surface of the second connecting shaft is fixed with a second small gear that meshes with the second large gear.

[0018] By adopting the above technical solution, the rotation of the first motor can drive the first connecting shaft to rotate, the rotation of the first connecting shaft can drive the first small gear to rotate, the rotation of the first small gear can drive the first large gear and the second connecting shaft to rotate at a reduced speed, the rotation of the second connecting shaft can drive the second small gear to rotate, and the rotation of the second small gear can drive the second large gear and the stirring rod to rotate at a reduced speed.

[0019] Preferably, a conveying assembly corresponding to the discharge pipe is provided inside the first mobile frame, and the conveying assembly includes a conveying frame provided inside the first mobile frame, and two symmetrical conveying rollers rotatably provided on the inner wall of the conveying frame, and the surfaces of the two conveying rollers are sleeved with a conveyor belt, and the outer surface of the conveying frame is fixedly provided with a second motor for driving one conveying roller to rotate, the inner bottom wall of the first mobile frame is fixedly provided with a rotating frame, and the inner wall of the rotating frame is rotatably provided with a rotating block, the top end of the rotating block is fixedly connected to the lower surface of the conveying frame, and the inner bottom wall of the first mobile frame is equidistantly provided with three hydraulic rods, and the telescopic ends of the three hydraulic rods are all rotatably connected to the lower surface of the conveying frame; The inner bottom wall of the first movable frame and the outer surface of the mixing drum are respectively fixed with a first mobile power supply and a first controller.

[0020] By adopting the above technical solution, soil can be transported to the restoration area through the transport component.

[0021] Preferably, the liquid inlet end of the metering pump extends to the inner bottom of the bacteria liquid storage tank, and the liquid outlet end of the metering pump is provided with a connecting hose connected to the spray pipe.

[0022] By adopting the above technical solution, the microbial bacterial liquid in the bacterial liquid storage tank can be transported to the inside of the spray pipe through the metering pump.

[0023] Preferably, both ends of the spray pipe are fixed with a rotating shaft rotatably connected to the inner wall of the installation frame, and the spray pipe is rotatably connected to the inner wall of the installation frame through two rotating shafts, and the outer surface of the installation frame is fixed with a third motor for driving a rotating shaft to rotate.

[0024] By adopting the above technical solution, the angle of the spray pipe can be adjusted by rotating the third motor.

[0025] Preferably, a liquid adding pipe and a venting pipe are embedded on the top of the bacteria liquid storage tank, a sealing cover is provided on the top of the liquid adding pipe, and a filter is provided inside the venting pipe.

[0026] By adopting the above technical solution, bacterial liquid can be added to the interior of the bacterial liquid storage tank through the liquid adding pipe.

[0027] Preferably, a second mobile power supply is fixedly provided on the inner bottom wall of the second mobile rack, a second controller is fixedly provided on the surface of the second mobile rack, and a liquid level gauge is provided on the surface of the bacteria liquid storage tank.

[0028] By adopting the above technical solution, the amount of the microbial liquid inside the liquid storage tank can be observed through the liquid level meter.

[0029] The beneficial effects of the present invention are: The method and device for combined remediation of heavy metal-contaminated soil described in the present invention can accurately control the amount of curing agent and microorganism added and the duration of action, can formulate personalized remediation plans for soils of different contamination levels and types, and can achieve precise delivery of curing agents, efficient inoculation of microorganisms, and real-time monitoring of the soil remediation process, thereby improving remediation efficiency and quality.

[0030] The method and device for combined remediation of heavy metal contaminated soil described in the present invention, by providing a mixing component and a conveying component, can drive the stirring blades to fully stir the soil inside the mixing drum, so that the soil and the curing agent can be fully mixed, and can also drive the conveyor belt to rotate and transport the soil to a designated location, facilitating the next step of soil processing.

[0031] The method and device for combined remediation of heavy metal-contaminated soil described in the present invention are configured with a microbial inoculation device. After the soil to which a curing agent is added is transported to the remediation area via a transport assembly, the device can move a second mobile frame and start a metering pump to transport the bacterial liquid in the bacterial liquid storage tank to a spray pipe via a connecting hose. The liquid is then evenly sprayed onto the soil surface via an atomizing nozzle, thereby achieving microbial inoculation of the soil. During the spraying process, the spraying angle of the atomizing nozzle on the spray pipe can be adjusted by a third motor. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is a step diagram of the method for repairing heavy metal contaminated soil by combining a curing agent and microorganisms of the present invention; Figure 2 It is a schematic diagram of the three-dimensional structure of the soil processing equipment of the present invention; Figure 3 It is a side structural schematic diagram of the soil processing equipment of the present invention; Figure 4 This is a bottom-up structural diagram of the soil processing equipment of the present invention; Figure 5 This is a schematic diagram of the internal structure of the mixing drum and reduction box of the present invention; Figure 6 This invention Figure 5 A in the middle is an enlarged structural diagram; Figure 7 It is a schematic diagram of the three-dimensional structure of the microbial inoculation device of the present invention; Figure 8 It is a rear structural schematic diagram of the microbial inoculation device of the present invention; Figure 9 It is a side structural schematic diagram of the microbial inoculation device of the present invention.

[0033] Description of reference numerals: 100. Soil treatment equipment; 200, mixing assembly; 201, first mobile frame; 202, mixing drum; 203, feed port; 204, discharge pipe; 205, stirring rod; 206, stirring blade; 207, scraper; 208, spiral conveyor blade; 209, reduction gear; 2010, first motor; 2011, first connecting shaft; 2012, second connecting shaft; 2013, first pinion; 2014, first large gear; 2015, second large gear; 2016, second pinion; 300, microbial inoculation equipment; 301, second mobile rack; 302, bacterial liquid storage tank; 303, metering pump; 304, mounting frame; 305, spray pipe; 306, atomizing nozzle; 307, connecting hose; 308, third motor; 309, liquid adding pipe; 3010, vent pipe; 3011, liquid level gauge; 400, conveying assembly; 401, conveying frame; 402, conveying roller; 403, conveying belt; 404, second motor; 405, hydraulic rod. DETAILED DESCRIPTION

[0034] The subject matter described herein will now be discussed with reference to exemplary embodiments. It should be understood that these embodiments are discussed solely to enable those skilled in the art to better understand and implement the subject matter described herein, and that the functions and arrangements of the elements discussed may be varied without departing from the scope of this specification. Various examples may omit, substitute, or add various processes or components as needed. In addition, features described with respect to some examples may also be combined in other examples. Example

[0035] The following is a further detailed description of the technical solution of the present invention in conjunction with the accompanying drawings and specific embodiments. Figures 1 to 9 , this application provides a method for combined remediation of heavy metal contaminated soil, please refer to Figure 1 , including the following steps: S1. Soil pretreatment: The soil to be repaired is sampled and analyzed to determine the type and content of heavy metals and the physical and chemical properties of the soil. Based on the analysis results, the soil is crushed and screened to improve the subsequent repair effect. X-ray fluorescence spectrometer can be used to quickly detect the type and content of heavy metal elements in the soil before and after repair to evaluate the repair effect. This method can detect multiple heavy metals at the same time and has the advantages of fast analysis speed and non-destructive testing.

[0036] S2. Screening and Adding Curing Agents: Screen the appropriate curing agent based on the type of heavy metal contamination in the soil. For example, for lead-contaminated soil, a phosphate curing agent can be used. Calculate and determine the amount of curing agent to add. Add the curing agent in layers to ensure thorough mixing with the soil. After addition, use mechanical stirring equipment to evenly distribute the curing agent throughout the soil. S3. Microbial inoculation and cultivation: Select microbial strains with strong tolerance and enrichment capabilities for the target heavy metals, such as cadmium-resistant Bacillus. Mix the cultured microbial solution with the nutrient solution at a ratio of 1:50 and inoculate it into the soil treated with the solidifying agent by spraying. Then, a layer of moisturizing and breathable material is covered on the soil surface to create an environment suitable for the growth of microorganisms and promote the colonization and reproduction of microorganisms in the soil; High-throughput sequencing technology was used to analyze the structure of soil microbial communities during the remediation process. By comparing changes in microbial communities before and after remediation, we can understand the mechanisms of microbial action during the remediation process and provide a basis for optimizing remediation plans.

[0037] S4. Process control and monitoring: Regularly monitor the soil's pH, redox potential, and heavy metal form change indicators. Based on the monitoring results, control the soil environment by adding acid-base regulators and ventilation to enable the curing agent and microorganisms to achieve the best repair effect.

[0038] Specifically, it can precisely control the amount of curing agent and microorganism added and the action time, and can formulate personalized remediation plans for soils with different degrees and types of pollution. It can also achieve precise delivery of curing agents, efficient inoculation of microorganisms, and real-time monitoring of the soil remediation process, thereby improving remediation efficiency and quality.

[0039] On the other hand, the present invention also provides a device for the combined repair of heavy metal contaminated soil according to the above method. Figures 2 to 9 , including: soil treatment equipment 100, which is used to mix soil with a curing agent added, the soil treatment equipment 100 includes a mixing assembly 200, the mixing assembly 200 includes a first mobile frame 201, and a mixing drum 202 fixed on the upper surface of the first mobile frame 201, the upper surface of the mixing drum 202 is provided with a feed inlet 203, and the bottom end of the mixing drum 202 is provided with a discharge pipe 204, and the surface of the discharge pipe 204 is provided with a discharge valve; a microbial inoculation device 300, which is used to spray microbial liquid on the treated soil, the microbial inoculation device 300 includes a second mobile frame 301, and a bacterial liquid storage tank 302 and a metering pump 303 respectively fixed on the inner bottom wall of the second mobile frame 301, and a mounting frame 304 is fixed on the side of the second mobile frame 301 through two mounting plates, a spray pipe 305 is provided inside the mounting frame 304, and a plurality of atomizing nozzles 306 are equidistantly provided on the lower surface of the spray pipe 305.

[0040] Specifically, the curing agent and the soil can be fully mixed, and the soil can be driven to be quickly discharged from the mixing drum 202 , and the microbial liquid can be evenly sprayed on the surface of the soil through the atomizing nozzle 306 .

[0041] Please refer to Figure 5 The inner top wall of the mixing drum 202 is rotatably provided with a stirring rod 205 extending to the inside of the discharge pipe 204. Two groups of stirring blades 206 are symmetrically fixed on the surface of the stirring rod 205, and the ends of the two groups of stirring blades 206 are fixed with scrapers 207 that are slidably connected to the inner wall of the mixing drum 202. The surface of the stirring rod 205 is also fixed with spiral conveying blades 208 that are adapted to the inner wall of the discharge pipe 204.

[0042] Specifically, the rotation of the stirring rod 205 can drive the stirring blade 206 to fully stir the soil and the curing agent, and the setting of the spiral conveying blade 208 can turn the bottom soil upward during stirring, and drive the soil to automatically enter the discharge pipe 204 during discharge.

[0043] Please refer to Figure 6 A reduction gear box 209 is fixed on the upper surface of the mixing drum 202, and the top end of the mixing rod 205 extends to the interior of the reduction gear box 209. A first motor 2010 for driving the mixing rod 205 to rotate at a reduced speed is fixed on the upper surface of the reduction gear box 209.

[0044] Specifically, the rotation of the first motor 2010 can drive the stirring rod 205 to rotate at a reduced speed.

[0045] Please refer to Figure 6 The inner wall of the reduction box 209 is respectively rotatably provided with a first connecting shaft 2011 and a second connecting shaft 2012, the output end of the first motor 2010 extends to the interior of the reduction box 209 and is fixedly connected to the top end of the first connecting shaft 2011, the surface of the first connecting shaft 2011 is fixed with a first small gear 2013, the surface of the second connecting shaft 2012 is fixed with a first large gear 2014 which is meshed with the first small gear 2013, the surface of the stirring rod 205 is fixed with a second large gear 2015, and the surface of the second connecting shaft 2012 is fixed with a second small gear 2016 which is meshed with the second large gear 2015.

[0046] Specifically, the rotation of the first motor 2010 can drive the first connecting shaft 2011 to rotate, the rotation of the first connecting shaft 2011 can drive the first small gear 2013 to rotate, the rotation of the first small gear 2013 can drive the first large gear 2014 and the second connecting shaft 2012 to slow down the rotation, the rotation of the second connecting shaft 2012 can drive the second small gear 2016 to rotate, and the rotation of the second small gear 2016 can drive the second large gear 2015 and the stirring rod 205 to slow down the rotation.

[0047] Please refer to Figure 2 The interior of the first movable frame 201 is provided with a conveying assembly 400 corresponding to the discharge pipe 204, and the conveying assembly 400 includes a conveying frame 401 arranged inside the first movable frame 201, and two symmetrical conveying rollers 402 rotatably arranged on the inner wall of the conveying frame 401, and the surfaces of the two conveying rollers 402 are provided with a conveyor belt 403, and the outer surface of the conveying frame 401 is fixedly provided with a second motor 404 for driving one conveying roller 402 to rotate, and the inner bottom wall of the first movable frame 201 is fixedly provided with a rotating frame, and the inner wall of the rotating frame is rotatably provided with a rotating block, the top of the rotating block is fixedly connected to the lower surface of the conveying frame 401, and three hydraulic rods 405 are equidistantly rotatably provided on the inner bottom wall of the first movable frame 201, and the telescopic ends of the three hydraulic rods 405 are all rotatably connected to the lower surface of the conveying frame 401; the inner bottom wall of the first movable frame 201 and the outer surface of the mixing drum 202 are respectively fixed with a first mobile power supply and a first controller.

[0048] Specifically, the soil can be transported to the restoration area through the transport assembly 400 .

[0049] The present invention provides a mixing assembly 200 and a conveying assembly 400. After adding a curing agent to the soil, the soil can be put into the mixing drum 202 through the feed port 203, and the first motor 2010 is started. The rotation of the first motor 2010 drives the first connecting shaft 2011 to rotate, and the rotation of the first connecting shaft 2011 drives the first small gear 2013 to rotate. The rotation of the first small gear 2013 drives the first large gear 2014 and the second connecting shaft 2012 to rotate at a reduced speed. The rotation of the second connecting shaft 2012 drives the second small gear 2016 to rotate. The rotation of the second small gear 2016 drives the second large gear 2015 and the stirring rod 205 to rotate at a reduced speed, thereby driving the stirring blade 206 to fully stir the soil inside the mixing drum 202, and at the same time drives the spiral conveying blade 208 to stir The soil at the bottom of the drum 202 is transported upward so that the soil and the curing agent can be fully mixed. When the stirring is completed, the first motor 2010 is started to reverse and the discharge valve is opened. The reversal of the first motor 2010 drives the stirring blade 206 to continue stirring while driving the spiral conveying blade 208 to rotate in the opposite direction, thereby driving the soil inside the mixing drum 202 to automatically enter the discharge pipe 204, realizing the smooth discharge of the soil. At the same time, it can also drive the scraper 207 to scrape the soil attached to the inner wall of the mixing drum 202 to prevent the soil from adhering to the inner wall of the mixing drum 202. When the soil passes through the discharge pipe 204 and reaches the conveyor belt 403, the second motor 404 can be started to drive a conveying roller 402 to rotate, thereby driving the conveyor belt 403 to rotate and transporting the soil to the designated position, so as to facilitate the next step of processing of the soil.

[0050] Please refer to Figure 7 The liquid inlet end of the metering pump 303 extends to the inner bottom of the bacteria liquid storage tank 302 , and the liquid outlet end of the metering pump 303 is provided with a connecting hose 307 connected to the spray pipe 305 .

[0051] Specifically, the microbial liquid in the liquid storage tank 302 can be transported to the inside of the spray pipe 305 by the metering pump 303 .

[0052] Please refer to Figure 8 Both ends of the spray pipe 305 are fixed with a rotating shaft that is rotatably connected to the inner wall of the installation frame 304, and the spray pipe 305 is rotatably connected to the inner wall of the installation frame 304 through two rotating shafts. The outer surface of the installation frame 304 is fixed with a third motor 308 for driving a rotating shaft to rotate.

[0053] Specifically, the angle of the spray pipe 305 can be adjusted by rotating the third motor 308 .

[0054] Please refer to Figure 8A liquid adding pipe 309 and a vent pipe 3010 are embedded on the top of the bacterial liquid storage tank 302 , and a sealing cover is provided on the top of the liquid adding pipe 309 , and a filter is provided inside the vent pipe 3010 .

[0055] Specifically, bacterial liquid can be added to the interior of the bacterial liquid storage tank 302 through the liquid adding pipe 309 .

[0056] Please refer to Figure 9 A second mobile power supply is fixedly installed on the inner bottom wall of the second mobile rack 301 , a second controller is fixedly installed on the surface of the second mobile rack 301 , and a liquid level gauge 3011 is installed on the surface of the bacteria liquid storage tank 302 .

[0057] Specifically, the amount of the microbial liquid inside the liquid storage tank 302 can be observed by the liquid level meter 3011 .

[0058] Among them, the present invention sets up a microbial inoculation device 300, so that after the soil added with the curing agent is transported to the repair area through the conveying component 400, the device can move the second mobile frame 301 and start the metering pump 303 to transport the bacterial liquid in the bacterial liquid storage tank 302 to the spray pipe 305 through the connecting hose 307, and evenly spray it to the surface of the soil through the atomizing nozzle 306 to achieve microbial inoculation of the soil. In addition, during the spraying process, the spraying angle of the atomizing nozzle 306 on the spray pipe 305 can be adjusted by the third motor 308.

[0059] The device for combining a curing agent and microorganisms to repair heavy metal-contaminated soil proposed in the present invention also includes a sensor mounting structure: a stainless steel sensor mounting rod is inserted into the soil, and the sensor is fixed to the mounting rod through a threaded connection or a slot. A rain cover is provided on the top of the mounting rod to protect the sensor from rain erosion. The sensor is connected to the central control system via a cable, and the cable uses a waterproof and anti-interference shielded wire.

[0060] Working principle: After adding the curing agent to the soil, the soil can be put into the mixing drum 202 through the feed port 203, and the first motor 2010 is started. The rotation of the first motor 2010 drives the first connecting shaft 2011 to rotate, and the rotation of the first connecting shaft 2011 drives the first small gear 2013 to rotate. The rotation of the first small gear 2013 drives the first large gear 2014 and the second connecting shaft 2012 to rotate at a reduced speed. The rotation of the second connecting shaft 2012 drives the second small gear 2016 to rotate. The rotation of the second small gear 2016 drives the second large gear 2015 and the stirring rod 205 to rotate at a reduced speed, thereby driving the stirring blade 206 to fully stir the soil inside the mixing drum 202, and at the same time drives the spiral conveying blade 208 to transport the soil at the bottom of the mixing drum 202 upward, so that the soil and the curing agent can be fully mixed. When the stirring is completed, the first motor 2010 is started to reverse, and the discharge valve is opened. The reverse rotation of the first motor 2010 drives the stirring blade 206 to continue stirring while driving the spiral conveying blade 208 in the opposite direction. The soil in the mixing drum 202 automatically enters the discharge pipe 204 to discharge the soil smoothly. At the same time, the scraper 207 is driven to scrape the soil attached to the inner wall of the mixing drum 202 to prevent the soil from adhering to the inner wall of the mixing drum 202. When the soil passes through the discharge pipe 204 and reaches the conveyor belt 403, the second motor 404 is started to drive a conveyor roller 402 to rotate, thereby driving the conveyor belt 403 to rotate and transport the soil to the designated position for the next step of soil treatment. After the soil with the curing agent added is transported to the repair area through the transport assembly 400, the second mobile frame 301 can be moved, and the metering pump 303 can be started to transport the bacterial liquid in the bacterial liquid storage tank 302 to the spray pipe 305 through the connecting hose 307, and evenly sprayed to the surface of the soil through the atomizing nozzle 306 to achieve microbial inoculation of the soil. In addition, during the spraying process, the spraying angle of the atomizing nozzle 306 on the spray pipe 305 can be adjusted by the third motor 308.

[0061] The above describes an embodiment of this specific implementation method, but this embodiment is not limited to the above specific implementation method. The above specific implementation method is merely illustrative and not restrictive. Ordinary technicians in this field can also make many forms based on the inspiration of this embodiment, all of which are protected by this embodiment.

Claims

1. A method for combined remediation of heavy metal contaminated soil, characterized in that: The following steps are involved: S1. Soil pretreatment: Sampling and analyzing the soil to be remediated to determine the type and content of heavy metals and the physical and chemical properties of the soil. Based on the analysis results, the soil is crushed and screened for pretreatment. S2. Screening and adding curing agents: Screen the appropriate curing agent based on the type of heavy metal pollution in the soil, and determine the amount of curing agent to be added through calculation. Add the curing agent in layers to ensure that the curing agent and the soil are fully mixed. After addition, use mechanical stirring equipment to stir the curing agent to ensure that it is evenly distributed in the soil. S3. Microbial inoculation and cultivation: Select microbial strains with strong tolerance and enrichment capabilities for the target heavy metals, mix the cultured microbial solution with the nutrient solution in appropriate proportions, and inoculate the solution into the soil treated with the solidifying agent by spraying. Then, a layer of moisturizing and breathable material is covered on the soil surface to create an environment suitable for the growth of microorganisms and promote the colonization and reproduction of microorganisms in the soil; S4. Process control and monitoring: Regularly monitor the soil's pH, redox potential, and heavy metal form change indicators. Based on the monitoring results, control the soil environment by adding acid-base regulators and ventilation to enable the curing agent and microorganisms to achieve the best repair effect.

2. A device for combined remediation of heavy metal contaminated soil, according to the method for combined remediation of heavy metal contaminated soil according to claim 1, characterized in that: include: A soil processing device (100) is used for mixing soil to which a curing agent is added, the soil processing device (100) comprising a mixing assembly (200), the mixing assembly (200) comprising a first movable frame (201), and a mixing drum (202) fixedly mounted on the upper surface of the first movable frame (201), a feed inlet (203) being provided on the upper surface of the mixing drum (202), and a discharge pipe (204) being provided at the bottom end of the mixing drum (202), and a discharge valve being provided on the surface of the discharge pipe (204); A microbial inoculation device (300) is used for spraying a microbial liquid on treated soil. The microbial inoculation device (300) includes a second mobile frame (301), and a liquid storage tank (302) and a metering pump (303) respectively fixed to the inner bottom wall of the second mobile frame (301). A mounting frame (304) is fixed to the side of the second mobile frame (301) through two mounting plates. A spray pipe (305) is provided inside the mounting frame (304), and a plurality of atomizing nozzles (306) are equidistantly provided on the lower surface of the spray pipe (305).

3. The device for combined remediation of heavy metal contaminated soil according to claim 2, characterized in that: The inner top wall of the mixing drum (202) is rotatably provided with a stirring rod (205) extending into the interior of the discharge pipe (204); the surface of the stirring rod (205) is symmetrically fixed with two groups of stirring blades (206); and the ends of the two groups of stirring blades (206) are fixed with scrapers (207) that are slidably connected to the inner wall of the mixing drum (202); the surface of the stirring rod (205) is also fixed with spiral conveying blades (208) that are compatible with the inner wall of the discharge pipe (204).

4. The device for combined remediation of heavy metal contaminated soil according to claim 3, characterized in that: A reduction gear box (209) is fixedly provided on the upper surface of the mixing drum (202), and the top end of the mixing rod (205) extends into the interior of the reduction gear box (209). A first motor (2010) for driving the mixing rod (205) to rotate at a reduced speed is fixedly provided on the upper surface of the reduction gear box (209).

5. The device for combined remediation of heavy metal contaminated soil according to claim 4, characterized in that: The inner wall of the reduction box (209) is rotatably provided with a first connecting shaft (2011) and a second connecting shaft (2012), the output end of the first motor (2010) extends into the interior of the reduction box (209) and is fixedly connected to the top end of the first connecting shaft (2011), the surface of the first connecting shaft (2011) is fixedly provided with a first small gear (2013), the surface of the second connecting shaft (2012) is fixedly provided with a first large gear (2014) that meshes with the first small gear (2013), the surface of the stirring rod (205) is fixedly provided with a second large gear (2015), and the surface of the second connecting shaft (2012) is fixedly provided with a second small gear (2016) that meshes with the second large gear (2015).

6. The device for combined remediation of heavy metal contaminated soil according to claim 2, characterized in that: A conveying assembly (400) corresponding to the discharge pipe (204) is provided inside the first movable frame (201), and the conveying assembly (400) includes a conveying frame (401) provided inside the first movable frame (201), and two symmetrical conveying rollers (402) rotatably provided on the inner wall of the conveying frame (401), and the surfaces of the two conveying rollers (402) are sleeved with a conveyor belt (403), and a second motor (404) for driving one conveying roller (402) to rotate is fixedly provided on the outer surface of the conveying frame (401), a rotating frame is fixedly provided on the inner bottom wall of the first movable frame (201), and a rotating block is rotatably provided on the inner wall of the rotating frame, and the top end of the rotating block is fixedly connected to the lower surface of the conveying frame (401), and three hydraulic rods (405) are rotatably provided on the inner bottom wall of the first movable frame (201), and the telescopic ends of the three hydraulic rods (405) are all rotatably connected to the lower surface of the conveying frame (401); A first mobile power source and a first controller are fixedly mounted on the inner bottom wall of the first movable frame (201) and the outer surface of the mixing drum (202), respectively.

7. The device for combined remediation of heavy metal contaminated soil according to claim 2, characterized in that: The liquid inlet end of the metering pump (303) extends to the inner bottom of the bacterial liquid storage tank (302), and the liquid outlet end of the metering pump (303) is provided with a connecting hose (307) that is connected to the spray pipe (305).

8. The device for combined remediation of heavy metal contaminated soil according to claim 2, characterized in that: Both ends of the spray pipe (305) are fixedly provided with rotating shafts rotatably connected to the inner wall of the installation frame (304), and the spray pipe (305) is rotatably connected to the inner wall of the installation frame (304) through the two rotating shafts. The outer surface of the installation frame (304) is fixedly provided with a third motor (308) for driving one rotating shaft to rotate.

9. The device for combined remediation of heavy metal contaminated soil according to claim 8, characterized in that: A liquid adding pipe (309) and a vent pipe (3010) are respectively embedded on the top of the bacterial liquid storage tank (302), and a sealing cover is provided on the top of the liquid adding pipe (309), and a filter is provided inside the vent pipe (3010).

10. The device for combined remediation of heavy metal contaminated soil according to claim 2, characterized in that: A second mobile power supply is fixedly provided on the inner bottom wall of the second mobile rack (301), a second controller is fixedly provided on the surface of the second mobile rack (301), and a liquid level meter (3011) is provided on the surface of the bacterial liquid storage tank (302).

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