A soil pollution pretreatment device

Abstract

The application belongs to the technical field of soil treatment, and particularly relates to a soil pollution pretreatment device. The technical scheme is as follows: a soil pollution pretreatment device comprises, from top to bottom, a waste soil feeding port, a waste downward extrusion cavity, a soil downward extrusion cavity and a waste soil discharging port which are connected in sequence, the top of the soil downward extrusion cavity is connected with an arched waste grid, an isolation cylinder is connected in the soil downward extrusion cavity, a lifting stirring device is installed in the isolation cylinder, a liquid pipeline for spraying leaching liquid and blending liquid is extended into the lower part of the isolation cylinder, and a micro-bubble liquid spraying device is connected to the lower part of the lifting stirring device. The application provides a soil pollution pretreatment device which can remove waste, and fully perform leaching and blending.

Description

Technical Field

[0001] This invention belongs to the field of soil treatment technology, and specifically relates to a soil pollution pretreatment device. Background Technology

[0002] Organic pollutants enter the soil through leakage, seepage, and other means, causing environmental pollution. These organic substances may be toxic, carcinogenic, or persistent, posing a threat to ecosystems and human health. The treatment of contaminated sludge is an important issue in the field of environmental protection, directly affecting water bodies, soil, and the surrounding ecological environment.

[0003] Currently, the main methods for remediating soil pollution include physical, chemical, and biological remediation technologies. However, these traditional remediation methods have the following major problems:

[0004] First, it is inefficient: traditional methods usually take a long time to significantly reduce the concentration of soil pollutants, which is difficult to meet the urgent needs in practical applications.

[0005] Second, high cost: Many repair methods require expensive equipment and reagents, resulting in high overall repair costs and limiting large-scale application.

[0006] Third, secondary pollution: Some methods may generate secondary pollution during the remediation process, such as chemical reagent residues or substandard discharge of treated wastewater, which further pollutes the environment.

[0007] Current soil pollution remediation methods lack adequate pretreatment of the soil. The soil contains significant amounts of waste, which negatively impacts treatment effectiveness when using existing methods. Furthermore, current methods do not adequately leach and blend the soil, hindering the separation of gas, liquid, and solid components in subsequent stages, resulting in poor remediation outcomes. Summary of the Invention

[0008] In order to solve the above-mentioned problems in the prior art, the purpose of the present invention is to provide a soil pollution pretreatment device that can remove waste and fully rinse and blend.

[0009] The technical solution adopted in this invention is as follows:

[0010] A soil pollution pretreatment device includes, from top to bottom, a waste soil inlet, a waste downward extrusion chamber, a soil downward extrusion chamber, and a waste soil outlet. The top of the soil downward extrusion chamber is connected to an arched waste grid. An isolation cylinder is connected inside the soil downward extrusion chamber. A lifting and stirring device is installed in the isolation cylinder. A liquid pipeline for spraying washing liquid and mixing liquid extends into the lower part of the isolation cylinder. A microbubble liquid injection device is connected to the lower part of the lifting and stirring device.

[0011] The arched waste grid of this invention blocks waste in the soil, allowing only soil to pass through. The waste slides along the arched waste grid to the inner wall of the waste downward squeezing chamber. The waste is squeezed downwards on the inner wall of the waste downward squeezing chamber and then discharged from the device, preventing the waste from affecting the subsequent soil treatment effect.

[0012] The soil downward squeezing chamber of this invention squeezes the soil downwards, and a portion of the soil reaching the bottom of the soil downward squeezing chamber is lifted into an isolation cylinder by a lifting and stirring device, and then discharged back into the upper part of the soil downward squeezing chamber from the top of the isolation cylinder. The lifting and stirring device also stirs the soil while lifting it, thereby achieving partial soil circulation and agitation.

[0013] A liquid pipeline extending from the lower part of the isolation cylinder contains a spray pipe for adding leaching and mixing liquids to the soil. A microbubble liquid injection device is connected to the lower part of the lifting and stirring device to spray microbubble liquid into the soil. Because some soil circulates and is thoroughly agitated between the soil downward extrusion chamber and the isolation cylinder, the leaching and mixing liquids are fully mixed with the soil, as are the microbubble liquids. This ensures thorough pretreatment of the soil within the device, improving the treatment efficiency of the soil before it enters the next process.

[0014] In a preferred embodiment of the present invention, a waste step plate is provided between the waste downward squeezing chamber and the soil downward squeezing chamber, and a plurality of waste discharge pipes are connected to the waste step plate. Under the obstruction and guidance of the arched waste grid, the waste in the soil is squeezed into the waste step plate along the waste downward squeezing chamber, and then discharged by the plurality of waste discharge pipes, thereby achieving reliable separation of waste from the soil and avoiding the waste from affecting the subsequent soil treatment effect.

[0015] As a preferred embodiment of the present invention, a vibrator is installed on the waste grid. The vibrator causes the waste on the waste grid to slide towards the inner wall of the waste downward compression chamber, preventing the waste from clogging the waste grid.

[0016] In a preferred embodiment of the present invention, the inner wall of the waste downward compression chamber is provided with an upper waste downward compression spiral and a lower waste downward compression spiral. The spiral teeth of the upper and lower waste downward compression spirals are of different heights. The upper waste downward compression spiral has smaller spiral teeth, allowing waste to easily enter its compression space, thus ensuring that waste sliding down from the waste grid can be smoothly compressed into the lower waste downward compression spiral. The lower waste downward compression spiral has larger spiral teeth, resulting in a better compression effect, ensuring that waste is reliably compressed onto the waste step plate and then discharged from the waste discharge pipe, avoiding situations where waste cannot enter the waste discharge pipe.

[0017] In a preferred embodiment of the present invention, a transmission wheel is installed on the lifting and mixing device, and a lifting and mixing power device for driving the transmission wheel to rotate is connected to the transmission wheel. The lifting and mixing power device drives the transmission wheel to rotate, and the transmission wheel drives the lifting and mixing device to rotate, thereby lifting and mixing the soil in the isolation cylinder in a spiral manner, realizing that part of the soil circulates and mixes between the soil downward extrusion chamber and the isolation cylinder.

[0018] As a preferred embodiment of the present invention, a soil downward squeezing spiral is provided on the inner wall of the soil downward squeezing chamber. During the process of soil circulation between the soil downward squeezing chamber and the isolation cylinder, the soil between the outer walls of the soil downward squeezing chamber and the isolation cylinder can move downward along the soil downward squeezing spiral, avoiding soil blockage of the channel.

[0019] In a preferred embodiment of the present invention, the microbubble liquid injection device includes a distribution plate, which is fixed to the bottom of the lifting and stirring device. A microbubble liquid inlet pipe is connected to the bottom of the distribution plate, and several microbubble liquid nozzles communicating with the microbubble liquid inlet pipe are arranged along the edge of the distribution plate. The microbubble liquid inlet pipe introduces the microbubble liquid into the distribution plate, and the several microbubble nozzles on the distribution plate spray the microbubble liquid evenly, thereby ensuring thorough mixing of the microbubble liquid with the soil.

[0020] As a preferred embodiment of the present invention, the bottom of the isolation cylinder is provided with a funnel-shaped circulation opening, into which a liquid pipeline extends, and the top of the isolation cylinder is provided with several mud outlets. The funnel-shaped circulation opening at the bottom of the isolation cylinder facilitates the entry of soil into the isolation cylinder, forming a circulation from the soil, and the washing liquid, mixing liquid, and microbubble liquid can be more fully mixed with the soil at the funnel-shaped circulation opening.

[0021] In a preferred embodiment of the present invention, the waste-containing soil inlet includes a funnel-shaped feed hopper and a constricted section, the diameter of which is smaller than the diameter of the waste-feeding downward extrusion chamber. The step between the constricted section and the waste-feeding downward extrusion chamber serves as a barrier to prevent waste-containing soil from entering through the waste-containing soil inlet.

[0022] In a preferred embodiment of the present invention, the leachate comprises a surfactant, a chelating agent, a pH adjuster, and a biosurfactant; the mass concentration of the surfactant is 0.5–1.5%, the mass concentration of the chelating agent is 0.3–0.8%, the pH of the pH adjuster is 7–8, and the mass concentration of the biosurfactant is 0.1–0.3%; the temperature of the leachate is 30–35°C. By rationally configuring the leachate and controlling its temperature, the soil receives sufficient and effective pretreatment.

[0023] The beneficial effects of this invention are as follows:

[0024] 1. The arched waste grid of the present invention blocks waste in the soil, allowing only soil to pass through the waste grid. The waste slides along the arched waste grid to the inner wall of the waste downward squeezing chamber. The waste is squeezed downward on the inner wall of the waste downward squeezing chamber and then discharged from the device, preventing the waste from affecting the subsequent soil treatment effect.

[0025] 2. The soil downward pressing chamber of the present invention presses the soil downward, and the portion of soil reaching the bottom of the soil downward pressing chamber is lifted into the isolation cylinder by the lifting and stirring device, and then discharged back into the upper part of the soil downward pressing chamber from the top of the isolation cylinder. The lifting and stirring device also stirs the soil while lifting it, thereby achieving partial soil circulation and agitation.

[0026] A liquid pipeline extending from the lower part of the isolation cylinder contains a spray pipe for adding leaching and mixing liquids to the soil. A microbubble liquid injection device is connected to the lower part of the lifting and stirring device to spray microbubble liquid into the soil. Because some soil circulates and is thoroughly agitated between the soil downward extrusion chamber and the isolation cylinder, the leaching and mixing liquids are fully mixed with the soil, as are the microbubble liquids. This ensures thorough pretreatment of the soil within the device, improving the treatment efficiency of the soil before it enters the next process. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the structure of the present invention;

[0028] Figure 2 This is a cross-sectional view of the invention in the first direction;

[0029] Figure 3 This is a cross-sectional view of the invention in a second direction.

[0030] In the diagram: 1-Inlet containing waste soil; 2-Waste downward extrusion chamber; 3-Soil downward extrusion chamber; 4-Waste soil discharge outlet; 5-Waste grid; 6-Isolation cylinder; 7-Lifting and stirring device; 8-Liquid pipeline; 9-Microbubble liquid injection device; 11-Feed hopper; 12-Neck section; 21-Waste step plate; 22-Waste discharge pipeline; 23-Upper spiral for downward extrusion of waste; 24-Lower spiral for downward extrusion of waste; 31-Soil downward extrusion spiral; 51-Vibrator; 52-Flexible connection device; 61-French-shaped circulation opening; 62-Slurry outlet; 63-Fixed frame; 71-Drive wheel; 72-Lifting and stirring power device; 91-Distribution plate; 92-Microbubble liquid inlet pipeline; 93-Microbubble liquid nozzle. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0032] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention. It should be noted that, unless otherwise specified, the embodiments and features described in the embodiments of the invention can be combined with each other.

[0033] like Figures 1-3 As shown, the soil pollution pretreatment device of this embodiment includes, from top to bottom, a waste soil inlet 1, a waste downward extrusion chamber 2, a soil downward extrusion chamber 3, and a waste soil outlet 4. An arched waste grid 5 is connected to the top of the soil downward extrusion chamber 3. An isolation cylinder 6 is connected inside the soil downward extrusion chamber 3. A lifting and stirring device 7 is installed in the isolation cylinder 6. A liquid pipeline 8 for spraying in washing liquid and mixing liquid extends into the lower part of the isolation cylinder 6. A microbubble liquid injection device 9 is connected to the lower part of the lifting and stirring device 7.

[0034] The arched waste grid 5 of this invention blocks waste in the soil, allowing only soil to pass through. The waste slides along the arched waste grid 5 to the inner wall of the waste downward squeezing chamber 2. The waste is squeezed downwards on the inner wall of the waste downward squeezing chamber 2 and then discharged from the device, preventing the waste from affecting the subsequent soil treatment effect.

[0035] The soil downward squeezing chamber 3 of this invention squeezes the soil downwards, and a portion of the soil reaching the bottom of the soil downward squeezing chamber 3 is lifted by the lifting and stirring device 7 into the isolation cylinder 6, and then discharged back into the upper part of the soil downward squeezing chamber 3 from the top of the isolation cylinder 6. The lifting and stirring device 7 also stirs the soil while lifting it, thereby achieving partial soil circulation and agitation.

[0036] A liquid pipeline 8 extends from the lower part of the isolation cylinder 6, through which leachate and mixing liquid are injected into the soil. A microbubble liquid injection device 9 is connected to the lower part of the lifting and stirring device 7 to inject microbubble liquid into the soil. Because some soil circulates and is thoroughly agitated between the soil downward squeezing chamber 3 and the isolation cylinder 6, the leachate and mixing liquid are fully mixed with the soil, and the microbubble liquid is also fully mixed with the soil. This ensures that the soil is adequately pretreated within the device, improving the treatment effect of the soil entering the next process.

[0037] A waste step plate 21 is provided between the waste downward compression chamber 2 and the soil downward compression chamber 3, and several waste discharge pipes 22 are connected to the waste step plate 21. A waste grid 5 extends into the waste downward compression chamber 2 to discharge waste onto its inner wall. Under the obstruction and guidance of the arched waste grid 5, waste in the soil is compressed along the waste downward compression chamber 2 onto the waste step plate 21, and then discharged through the waste discharge pipes 22, achieving reliable separation of waste from the soil and preventing waste from affecting subsequent soil treatment.

[0038] Furthermore, a vibrator 51 is installed on the waste grid 5. The vibrator 51 allows the waste on the waste grid 5 to slide towards the inner wall of the waste downward compression chamber 2, preventing the waste from clogging the waste grid 5. The waste grid 5 is connected to the top of the soil downward compression chamber 3 via a flexible connecting device 52.

[0039] The waste downward compression chamber 2 has an upper waste downward compression spiral 23 and a lower waste downward compression spiral 24 on its inner wall. The spiral teeth of the upper waste downward compression spiral 23 and the lower waste downward compression spiral 24 are of different heights. The upper waste downward compression spiral 23 has smaller spiral teeth, making it easier for waste to enter its compression space, thus allowing waste sliding off the waste grid 5 to be smoothly compressed onto the lower waste downward compression spiral 24. The lower waste downward compression spiral 24 has larger spiral teeth, resulting in a better compression effect, ensuring that waste is reliably compressed onto the waste step plate 21 and then discharged from the waste discharge pipe 22, preventing situations where waste cannot enter the waste discharge pipe 22.

[0040] Specifically, the lifting and mixing device 7 is equipped with a transmission wheel 71, and a lifting and mixing power device 72 for driving the transmission wheel 71 to rotate is connected to the transmission wheel 71. The lifting and mixing power device 72 drives the transmission wheel 71 to rotate, and the transmission wheel 71 drives the lifting and mixing device 7 to rotate, thereby lifting and mixing the soil in the isolation cylinder 6 in a spiral manner, realizing that some soil circulates and mixes between the soil downward extrusion chamber 3 and the isolation cylinder 6. The isolation cylinder 6 is fixed in the soil downward extrusion chamber 3 by a fixing frame 63.

[0041] The lifting and stirring power device 72 may include a motor, the output end of which is connected to a reducer, and the output end of the reducer is connected to a drive pulley. The drive pulley and the transmission pulley 71 are connected by belt drive. Furthermore, the transmission pulley 71 may be provided at both the upper and lower parts of the lifting and stirring device 7 to improve the stability of the lifting and stirring device 7 during rotation.

[0042] The soil downward squeezing chamber 3 is provided with a soil downward squeezing spiral 31 on its inner wall. During the process of soil circulation between the soil downward squeezing chamber 3 and the isolation cylinder 6, the soil between the outer walls of the soil downward squeezing chamber 3 and the isolation cylinder 6 can move downward along the soil downward squeezing spiral 31 to avoid soil blockage of the channel.

[0043] Specifically, the microbubble liquid injection device 9 includes a distribution plate 91, which is fixed to the bottom of the lifting and stirring device 7. A microbubble liquid inlet pipe 92 is connected to the bottom of the distribution plate 91, and several microbubble liquid nozzles 93 connected to the microbubble liquid inlet pipe 92 are arranged along the edge of the distribution plate 91. The microbubble liquid inlet pipe 92 introduces microbubble liquid into the distribution plate 91, and the several microbubble nozzles on the distribution plate 91 spray the microbubble liquid evenly, thereby ensuring thorough mixing of the microbubble liquid with the soil.

[0044] Microbubble liquid is sprayed from microbubble liquid nozzle 93. The specific method is determined according to the soil pollution status of waste soil inlet 1: if COD < 1000 mg / L, oxygen is used as microbubble gas; if COD > 1000 mg / L, ozone is used as microbubble gas.

[0045] To facilitate soil entry into the isolation cylinder 6, a funnel-shaped circulation opening 61 is provided at the bottom of the isolation cylinder 6, and a liquid pipeline 8 extends into the funnel-shaped circulation opening 61. Several mud outlets 62 are provided at the top of the isolation cylinder 6. The funnel-shaped circulation opening 61 at the bottom of the isolation cylinder 6 facilitates soil entry into the isolation cylinder 6, forming a circulation from the soil, and the leachate, mixing liquid, and microbubble liquid can be more fully mixed with the soil at the funnel-shaped circulation opening 61.

[0046] Specifically, the waste soil inlet 1 includes a funnel-shaped feed hopper 11 and a constricted section 12, the diameter of which is smaller than the diameter of the waste downward extrusion chamber 2. The step between the constricted section and the waste downward extrusion chamber 2 serves as a barrier to prevent the waste-containing soil from entering from the waste soil inlet 1.

[0047] The leachate comprises a surfactant, a chelating agent, a pH adjuster, and a biosurfactant; the surfactant has a mass concentration of 0.5–1.5%, the chelating agent has a mass concentration of 0.3–0.8%, the pH adjuster has a pH of 7–8, and the biosurfactant has a mass concentration of 0.1–0.3%; the leachate temperature is 30–35°C. By rationally configuring the leachate and controlling its temperature, the soil receives sufficient and effective pretreatment.

[0048] Specifically, the eluent formulation is as follows:

[0049] 1) Surfactants: Novel surfactants (such as alkanolamides, alkyl polyglycosides, methyl ester sulfonates, and alkyl ester alcohol ethanolamines) generally have good solubility and surface activity, and are stable over a wide pH range; specific concentration: 0.5–1.5% (w / w);

[0050] 2) Chelating agent: EDTA; specific concentration: 0.3–0.8% (w / w);

[0051] 3) pH adjuster: Use citric acid or sodium hydroxide to adjust the pH of the rinsing solution to keep it within the optimal working range (pH 7-8);

[0052] 4) Biosurfactants: such as rhamnolipids, surfactant peptides, lipopeptide surfactants, phospholipid surfactants and monoglycerides; specific concentration: 0.1-0.3% (w / w).

[0053] The above-mentioned leachate formulation is innovative in the field of contaminated soil treatment, specifically in the following aspects:

[0054] 1) Use of novel surfactants:

[0055] The novel surfactants mentioned in the formulation, such as alkanolamides, alkyl polyglycosides, and methyl ester sulfonates, exhibit good solubility and surface activity, and are stable over a wide pH range. These properties enable them to dissolve and remove pollutants more efficiently during soil leaching, offering certain advantages compared to traditional surfactants.

[0056] 2) Introduction of biosurfactants:

[0057] The biosurfactants used in the formulation, such as rhamnolipids and lipopeptides, are biodegradable natural products with low toxicity and environmental friendliness. These biosurfactants effectively reduce surface tension and increase the bioavailability of pollutants, thereby improving removal efficiency. At the same time, the use of biosurfactants also helps reduce secondary pollution to the environment caused by chemical treatment.

[0058] 3) Synergistic effect of multiple components:

[0059] This formulation combines chemical surfactants, chelating agents, biosurfactants, and pH adjusters to form a multi-component synergistic system. Each component exerts its maximum effectiveness under specific conditions, and their interactions further enhance the removal of different types of organic pollutants.

[0060] 4) Mild operating conditions:

[0061] Using relatively mild operating conditions (such as a temperature between 30-35°C and a pH between 7-8) not only helps maintain system stability but also reduces energy consumption and treatment costs. This is more environmentally friendly and economically efficient compared to some traditional treatment methods.

[0062] Preparation of contaminated soil materials:

[0063] Soil sampling: Uncontaminated soil was collected, and contaminated soil material was prepared according to a certain proportion. The soil samples were dried and then passed through a 2mm sieve.

[0064] Soil pretreatment: Before the experiment, the soil was mixed evenly and its basic physicochemical properties (such as pH, organic matter content, etc.) were measured.

[0065] Leaching process: At room temperature, mix the prepared leachate with the soil at a solid-liquid ratio of 1:5 (e.g., add 500 mL of leachate to 100 g of soil), adjust the pH, and stir for 60 minutes. Use a constant temperature water bath to control the temperature.

[0066] Separation: After rinsing, the liquid phase and solid phase were separated by centrifugation (3000 rpm, 10 minutes), and the supernatant was collected for pollutant concentration analysis.

[0067] Eluent recovery: Surfactants in the supernatant can be recovered through membrane filtration or other technologies to reduce environmental burden.

[0068] Residual analysis: The concentration of residual pollutants was determined after the leached soil was dried.

[0069] Example 1: Soils with moderate organic and heavy metal contamination:

[0070] Soil background:

[0071] Organic pollutants (such as polycyclic aromatic hydrocarbons, PAHs): initial concentration 100 mg / kg;

[0072] Heavy metal pollutants (such as lead, Pb): initial concentration 300 mg / kg.

[0073] Rinse solution formulation:

[0074] Surfactant (alkanolamide): 1.0% (w / w);

[0075] Chelating agent (EDTA): 0.5% (w / w);

[0076] pH adjuster: citric acid, adjust pH to 7.5;

[0077] Biosurfactant (rhamnolipid): 0.2% (w / w).

[0078] Temperature: 32℃.

[0079] result:

[0080] Organic pollutant concentration: reduced to 15 mg / kg after rinsing (removal rate 85%);

[0081] Heavy metal pollutant concentration: reduced to 60 mg / kg after rinsing (removal rate 80%).

[0082] Compared to conventional chemical rinsing:

[0083] The removal rates of conventional chemical rinsing (using only EDTA as a chelating agent and without surfactants) were 60% (PAHs) and 65% (Pb).

[0084] Analysis of the reasons: The synergistic effect of surfactants and biosurfactants enhances the ability to dissolve and migrate organic pollutants, while improving the chelation effect of EDTA on heavy metals.

[0085] Example 2: Soils with severe organic pollution and mild heavy metal pollution:

[0086] Soil background:

[0087] Organic pollutants (such as petroleum hydrocarbons, TPH): initial concentration 500 mg / kg;

[0088] Heavy metal pollutants (such as cadmium, Cd): initial concentration 50 mg / kg.

[0089] Rinse solution formulation:

[0090] Surfactant (methyl ester sulfonate): 1.5% (w / w);

[0091] Chelating agent (EDTA): 0.7% (w / w);

[0092] pH adjuster: sodium hydroxide, adjust pH to 8.0;

[0093] Biosurfactant (surfactant peptide): 0.3% (w / w).

[0094] Temperature: 34℃.

[0095] result:

[0096] Organic pollutant concentration: reduced to 50 mg / kg after rinsing (removal rate 90%);

[0097] Heavy metal pollutant concentration: reduced to 10 mg / kg after rinsing (removal rate 80%).

[0098] Compared to conventional chemical rinsing:

[0099] Conventional chemical rinsing (using EDTA only) achieved removal rates of 70% (TPH) and 50% (Cd), respectively.

[0100] Analysis of the reasons: The combination of highly efficient surfactants and biosurfactants significantly improved the removal rate of high-concentration organic pollutants, while the alkaline conditions regulated by sodium hydroxide were conducive to the dissolution of heavy metals.

[0101] Example 3: Soils with mild organic pollution and severe heavy metal pollution:

[0102] Soil background:

[0103] Organic pollutants (such as benzene): initial concentration 50 mg / kg;

[0104] Heavy metal pollutants (such as arsenic, As): initial concentration 500 mg / kg.

[0105] Rinse solution formulation:

[0106] Surfactant (alkyl polysaccharide): 0.5% (w / w);

[0107] Chelating agent (EDTA): 0.8% (w / w);

[0108] pH adjuster: citric acid, adjust pH to 7.0;

[0109] Biosurfactant (monoglyceride): 0.1% (w / w).

[0110] Temperature: 30℃.

[0111] result:

[0112] Organic pollutant concentration: reduced to 10 mg / kg after rinsing (removal rate 80%);

[0113] Heavy metal pollutant concentration: reduced to 100 mg / kg after rinsing (removal rate 80%).

[0114] Compared to conventional chemical rinsing:

[0115] The removal rates of conventional chemical rinsing were 50% (Benzene) and 60% (As), respectively.

[0116] Analysis of the reasons: Although the initial concentration of organic pollutants was low, the removal rate was further optimized by using a suitable combination of surfactants and chelating agents. For heavy metal pollution, the highly efficient chelating effect of EDTA significantly improved the removal rate of heavy metals.

[0117] This invention is not limited to the above-described optional embodiments. Anyone can derive other various forms of products under the guidance of this invention. However, regardless of any changes made in their shape or structure, any technical solution that falls within the scope of the claims of this invention shall be protected by this invention.

Claims

1. A soil pollution pretreatment device, characterized in that: The structure includes, from top to bottom, a waste soil inlet (1), a waste downward extrusion chamber (2), a soil downward extrusion chamber (3), and a waste soil outlet (4). The top of the soil downward extrusion chamber (3) is connected to an arched waste grid (5). An isolation cylinder (6) is connected inside the soil downward extrusion chamber (3). A lifting and stirring device (7) is installed in the isolation cylinder (6). A liquid pipeline (8) for spraying in washing liquid and mixing liquid extends into the lower part of the isolation cylinder (6). A microbubble liquid injection device (9) is connected to the lower part of the lifting and stirring device (7). A waste step plate (21) is provided between the waste downward squeezing chamber (2) and the soil downward squeezing chamber (3), and a number of waste discharge pipes (22) are connected to the waste step plate (21); the waste grid (5) extends into the waste downward squeezing chamber (2) so as to discharge the waste to the inner wall of the waste downward squeezing chamber (2); under the blocking and guiding effect of the arched waste grid (5), the waste in the soil is squeezed along the waste downward squeezing chamber (2) to the waste step plate (21), and then discharged by the waste discharge pipes (22); A vibrator (51) is installed on the waste grid (5), and the waste grid (5) is connected to the top of the soil downward compression chamber (3) by a flexible connecting device (52); The inner wall of the waste downward squeezing chamber (2) is provided with an upper waste downward squeezing spiral (23) and a lower waste downward squeezing spiral (24). The height of the spiral teeth of the upper waste downward squeezing spiral (23) is smaller than that of the lower waste downward squeezing spiral (24). The spiral teeth of the upper waste downward squeezing spiral (23) are smaller, making it easier for waste to enter its squeezing space. Thus, waste that slides off the waste grid (5) can be smoothly squeezed into the lower waste downward squeezing spiral (24). The spiral teeth of the lower waste downward squeezing spiral (24) are larger, resulting in a better squeezing effect. Thus, waste can be reliably squeezed onto the waste step plate (21) and then discharged from the waste discharge pipe (22), preventing waste from being unable to enter the waste discharge pipe (22). The microbubble liquid injection device (9) includes a liquid distribution plate (91), which is fixed to the bottom of the lifting and stirring device (7). The bottom of the liquid distribution plate (91) is connected to a microbubble liquid inlet pipe (92), and the edge of the liquid distribution plate (91) is provided with a number of microbubble liquid nozzles (93) that are connected to the microbubble liquid inlet pipe (92). The rinsing solution comprises a surfactant, a chelating agent, a pH adjuster, and a biosurfactant; the mass concentration of the surfactant is 0.5–1.5%, the mass concentration of the chelating agent is 0.3–0.8%, and the mass concentration of the biosurfactant is 0.1–0.3%; the temperature of the rinsing solution is 30–35°C; the surfactant is an alkanolamide, an alkyl polysaccharide, a methyl ester sulfonate, or an alkyl ester alcohol ethanolamine, and the biosurfactant is a rhamnolipid, a surfactant peptide, a lipopeptide surfactant, a phospholipid surfactant, or a monoglyceride.

2. The soil pollution pretreatment device according to claim 1, characterized in that: The lifting and stirring device (7) is equipped with a transmission wheel (71), and the transmission wheel (71) is connected to a lifting and stirring power device (72) for driving the transmission wheel (71) to rotate.

3. The soil pollution pretreatment device according to claim 1, characterized in that: The soil downward squeezing chamber (3) is provided with a soil downward squeezing spiral (31) on its inner wall.

4. The soil pollution pretreatment device according to claim 1, characterized in that: The bottom of the isolation cylinder (6) is provided with a funnel-shaped circulation opening (61), and the liquid pipeline (8) extends into the funnel-shaped circulation opening (61). The top of the isolation cylinder (6) is provided with several mud outlets (62).

5. A soil pollution pretreatment device according to claim 1, characterized in that: The waste soil inlet (1) includes a funnel-shaped feed hopper (11) and a narrowed section (12), the diameter of which is smaller than the diameter of the waste downward extrusion chamber (2).

Images