A microbial composting device for petroleum contaminated soil

Abstract

This invention discloses a microbial composting treatment device for petroleum-contaminated soil, comprising: a composting tank and a stirring and oxygenation device. The composting tank has a receiving cavity, an inlet, and an outlet. The stirring and oxygenation device includes a spiral auger and an air guide pipe. A driven gear is located at the bottom of the spiral auger. The first cavity of the air guide pipe is connected to the air inlet of the air guide pipe. The air guide pipe has multiple first through holes communicating with the receiving cavity, with both ends of the first through holes connecting the receiving cavity and the first cavity of the air guide pipe, respectively. During the tumbling process, the spiral auger promotes the homogenization of pollutant concentration throughout the compost pile, thereby improving the microbial degradation efficiency. The air guide pipe extends along the axis of the spiral auger and rotates synchronously with it. It is connected to an external fan via a rotary joint, allowing air to pass through the first cavity of the air guide pipe and then be evenly dispersed into the soil compost pile through the multiple first through holes. This achieves synergistic operation of tumbling and oxygenation, enabling oxygen to reach deep areas of the compost pile.

Description

Technical Field

[0001] This invention relates to the field of soil remediation technology, and in particular to a microbial composting treatment device for oil-contaminated soil. Background Technology

[0002] Spills during oil extraction, transportation, and storage can lead to extensive soil contamination, posing a long-term potential threat to terrestrial ecosystems and human health. Such contaminated soils can be remediated through microbial methods. This involves artificially controlling key environmental parameters within the contaminated soil mass, such as temperature, humidity, oxygen supply, and nutrient ratios, to provide suitable growth and metabolic conditions for microbial degradation of petroleum hydrocarbon pollutants, thereby effectively promoting soil purification.

[0003] However, the degradation effect is highly sensitive to environmental conditions such as temperature, humidity, and oxygen concentration. Fluctuations in these parameters can significantly affect the enzyme activity and metabolic capacity of microorganisms, thus limiting the overall remediation efficiency. The degradation process of petroleum pollutants by microorganisms is usually time-consuming, and the remediation cycle is limited by the growth and reproduction rate of the microorganisms themselves. Summary of the Invention

[0004] In order to overcome the shortcomings of the prior art, the present invention aims to provide a microbial composting treatment device for oil-contaminated soil, which improves the treatment efficiency of contaminated soil.

[0005] The objective of this invention is achieved through the following technical solution:

[0006] A microbial composting treatment device for oil-contaminated soil includes:

[0007] A composting tank has a receiving cavity for containing petroleum-contaminated soil. The composting tank is provided with an inlet and an outlet, and the inlet, the receiving cavity, and the outlet are connected in sequence.

[0008] A stirring and aeration device includes a spiral auger and an air guide pipe. The spiral auger is disposed inside the receiving cavity and is rotatably connected to the composting tank. A driven gear is provided at the bottom of the spiral auger and is located outside the receiving cavity. The driven gear is used to drive a power source. The air guide pipe extends along the axial direction of the spiral auger. The first cavity of the air guide pipe is connected to the air inlet of the air guide pipe. The air inlet of the air guide pipe is used to connect to the air outlet of an external fan through a rotary joint. The air guide pipe has multiple first through holes that communicate with the receiving cavity. The two ends of the first through holes are respectively connected to the receiving cavity and the first cavity of the air guide pipe.

[0009] Furthermore, multiple air guide pipes are connected to the first through hole. The multiple air guide pipes are distributed at intervals along the spiral extension path of the spiral auger. The air guide pipes extend radially outward along the spiral auger. Each air guide pipe is provided with a second through hole. The second through hole extends radially along the air guide pipe and connects the second lumen of the air guide pipe and the receiving cavity.

[0010] Furthermore, multiple second through holes are provided, and the multiple second through holes are distributed along the axial direction of the air guide branch pipe. The second through holes are arranged facing the bottom of the receiving cavity, and the diameter of the second through hole is smaller than the diameter of the first through hole.

[0011] Furthermore, the composting tank has a plurality of electrode rods on its sidewall, which are spaced apart along the axial and / or circumferential direction of the composting tank. The electrode rods are used to collect electrons generated during the microbial degradation of petroleum pollutants and transmit them outward.

[0012] Furthermore, multiple electrode rods are spaced apart along the axial direction of the composting tank. Multiple electrode rods at the same horizontal height constitute a group of electrodes of the same polarity. Adjacent groups of electrodes have different polarities and are electrically connected by wires.

[0013] Furthermore, the conductor is equipped with a sensor and a power source, the sensor being used to detect the current flowing through the conductor, and the power source being used to provide driving force for electronic transmission.

[0014] Furthermore, the bottom of the composting tank is provided with a water filter layer and a filtrate outlet. The water filter layer is used to prevent soil particles from entering the filtrate outlet. The inner bottom wall of the composting tank is inclined, and the filtrate outlet is located on the lowest side of the inner bottom wall.

[0015] Furthermore, the discharge port is located at the bottom of the composting tank, and the discharge port is equipped with a valve. The valve is detachably connected to the composting tank to control the opening or closing of the discharge port. The top surface of the valve smoothly transitions to the inner bottom wall of the composting tank to avoid soil residue and guide the filtrate to the filtrate outlet.

[0016] Furthermore, the composting tank is also connected to an exhaust pipe, which is located at the top of the composting tank and is used to discharge the waste gas generated during the microbial degradation process.

[0017] Furthermore, the microbial composting treatment device for petroleum-contaminated soil further includes a control unit, a temperature sensor, a humidity sensor, and a dissolved oxygen sensor. The temperature sensor, the humidity sensor, and the dissolved oxygen sensor are respectively connected to the control unit via signal connection. The temperature sensor, the humidity sensor, and the dissolved oxygen sensor are all disposed within the receiving cavity. The control unit controls the operation of the fan and the power source based on the detection signals from each sensor.

[0018] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0019] 1. The composting tank has a containment cavity for holding petroleum-contaminated soil. The composting tank has an inlet and an outlet, which are sequentially connected. The composting tank provides a closed space for the petroleum-contaminated soil through its containment cavity, effectively maintaining stable temperature and humidity inside the compost pile. This prevents external environmental fluctuations from interfering with microbial metabolic activities and inhibits the unorganized diffusion of volatile organic compounds, thereby reducing the risk of secondary pollution. The inlet is located at the top or side of the composting tank, facilitating the addition of contaminated soil, nutrients, and microbial agents to improve the contact efficiency between microorganisms and contaminants. The outlet is located at the bottom or lower side of the composting tank, allowing for the directional discharge of treated soil after the remediation cycle is completed, thereby reducing material residue and shortening batch cleanup time.

[0020] 2. The agitation and oxygenation device includes a spiral auger and an air guide pipe. The spiral auger is located inside the containment cavity and is rotatably connected to the composting tank. A driven gear is located at the bottom of the spiral auger outside the containment cavity and is used to drive the power source. In the agitation and oxygenation device, the spiral auger continuously rotates and agitates the soil inside the containment cavity, breaking up soil aggregates and preventing material compaction, thereby increasing the contact surface area between microorganisms and pollutants. The driven gear located outside the containment cavity and connected to the power source prevents lubricating oil or mechanical wear products from entering the containment cavity and causing secondary soil pollution. During the agitation process, the spiral auger transports the heavier petroleum components from the bottom upwards, promoting the homogenization of pollutant concentration throughout the compost pile, thereby improving the efficiency of microbial degradation.

[0021] 3. The air guide pipe extends along the axis of the auger. The first cavity of the air guide pipe is connected to the air inlet of the air guide pipe. The air inlet of the air guide pipe is used to connect to the air outlet of an external fan through a rotary joint. The air guide pipe has multiple first through holes that communicate with the receiving cavity. The two ends of the first through holes are respectively connected to the receiving cavity and the first cavity of the air guide pipe. The air guide pipe extends along the axis of the auger and rotates synchronously with it. It is connected to an external fan through a rotary joint, so that air is evenly dispersed into the soil pile through the multiple first through holes after passing through the first cavity of the air guide pipe. This achieves the coordinated operation of turning and oxygen supply, so that oxygen can reach the deep areas of the pile to avoid oxygen deficiency. At the same time, the through holes of the air guide pipe are not easily blocked by wet soil during rotation, which can maintain the ventilation performance for long-term operation. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the microbial composting treatment device for petroleum-contaminated soil according to the present invention.

[0023] Figure 2 for Figure 1 The sectional view shown.

[0024] In the diagram: 1. Compost bin; 2. Receiving cavity; 3. Inlet; 4. Outlet; 5. Spiral auger; 6. Air guide pipe; 7. Air inlet; 8. Driven gear; 9. Rotary joint; 10. First cavity; 11. First through hole; 12. Air guide branch pipe; 13. Second through hole; 14. Second cavity; 15. Electrode rod; 16. Wire; 17. Sensor; 18. Filter layer; 19. Filtrate outlet; 20. Valve; 21. Exhaust pipe. Detailed Implementation

[0025] The present invention will now be further described in conjunction with the accompanying drawings and specific embodiments. It should be noted that, without conflict, the various embodiments or technical features described below can be arbitrarily combined to form new embodiments.

[0026] It should be noted that when an element is described as being "fixed to" another element, it can be directly attached to the other element or there may be an intervening element. When an element is described as being "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementations.

[0027] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0028] See Figures 1-2 A preferred embodiment of the present invention provides a microbial composting treatment device for petroleum-contaminated soil, comprising: a composting tank 1 and a stirring and oxygenation device.

[0029] The composting tank 1 has a receiving cavity 2 for containing petroleum-contaminated soil. The composting tank 1 has an inlet 3 and an outlet 4, which are sequentially connected. The receiving cavity 2 of the composting tank 1 provides a closed reaction space for the petroleum-contaminated soil, effectively maintaining stable temperature and humidity inside the compost and preventing external environmental fluctuations from interfering with microbial metabolic activities. The inlet 3 is located at the top or side of the composting tank 1, facilitating the layered addition of contaminated soil, nutrients, and microbial agents, ensuring uniform mixing of materials and improving the contact efficiency between microorganisms and contaminants. The inlet 3 can be a funnel-shaped interface with a sealing cap; the cap is opened when adding contaminated soil and closed after feeding to prevent heat loss. The outlet 4 is located at the bottom or lower side of the composting tank 1, enabling the directional discharge of treated soil after the remediation cycle is completed, reducing material residue and shortening the cleanup time between batches. The sealing characteristics of the receiving cavity 2 also inhibit the unorganized diffusion of volatile organic compounds, reducing the risk of secondary pollution. In summary, the structure of this compost tank 1 effectively improves the operational continuity and environmental controllability of microbial composting treatment.

[0030] The stirring and aeration device includes a spiral auger 5 and an air guide pipe 6. The spiral auger 5 is located inside the receiving cavity 2 and is rotatably connected to the composting tank 1. A driven gear 8 is located at the bottom of the spiral auger 5 outside the receiving cavity 2 and is used to drive a power source. The air guide pipe 6 extends along the axis of the spiral auger 5. The first cavity 10 of the air guide pipe 6 is connected to the air inlet 7 of the air guide pipe 6. The air inlet 7 of the air guide pipe 6 is used to connect to the air outlet pipe of an external fan through a rotary joint 9. The air guide pipe 6 has multiple first through holes 11 that communicate with the receiving cavity 2. The two ends of the first through holes 11 are respectively connected to the receiving cavity 2 and the first cavity 10 of the air guide pipe 6. The continuous rotation of the spiral auger 5 agitates the petroleum-contaminated soil in the receiving cavity 2, effectively breaking up soil aggregates and preventing material compaction, thereby increasing the contact surface area between microorganisms and pollutants. The air duct 6 extends along the axis of the auger 5 and rotates synchronously with it. Air supplied by an external fan enters the first cavity 10 of the air duct 6 through the rotary joint 9, and is then evenly dispersed into the soil pile through multiple first through holes 11, achieving coordinated operation of turning and oxygen supply. The rotary joint 9 can be a spherical sealing type, achieving gas sealing through grinding the spherical surface and spring compression; or a mechanical sealing type, using the contact surfaces of the moving and stationary rings to prevent leakage; or a ball bearing type, using bearings to support rotation and using O-rings to achieve air passage connection. This integrated design allows oxygen to reach deep areas of the pile, avoiding the oxygen-deficient zones caused by traditional surface oxygen supply methods. Simultaneously, the through holes of the air duct 6 are less prone to blockage by wet soil during rotation, maintaining long-term ventilation performance. The driven gear 8 is located outside the receiving cavity 2, facilitating connection to the power source and preventing secondary pollution of the soil by lubricating oil or mechanical wear products. During the tumbling process, the auger 5 can also transport heavier petroleum components accumulated at the bottom upwards, promoting the homogenization of pollutant concentration throughout the compost pile and thus improving microbial degradation efficiency. Overall, this stirring and aeration device significantly improves mass transfer conditions and oxygen utilization in composting through the combined action of rotation and gas distribution.

[0031] Working principle: The composting tank 1's containment chamber 2 maintains stable temperature and humidity within the compost pile through a closed space, preventing external fluctuations from interfering with microbial metabolism. The feed inlet 3, located at the top, is used for layered addition of soil and nutrients, while the discharge outlet 4 is used for directional discharge after remediation. The sealed nature of the containment chamber 2 inhibits the diffusion of volatile organic compounds. The stirring and aeration device includes a screw conveyor 5 and an air guide pipe 6. The screw conveyor 5 is located inside the containment chamber 2 and rotatably connected to the composting tank 1. A driven gear 8, located outside the containment chamber 2, is located at its bottom. The driven gear 8 is connected to a power source, driving the screw conveyor 5 to continuously rotate and agitate the soil. Mechanical shearing breaks up soil aggregates to increase the contact area between microorganisms and contaminants. The air duct 6 extends along the axis of the auger 5 and rotates synchronously with it. The air inlet 7 of the air duct 6 is connected to an external fan via a rotary joint 9. The air duct 6 has multiple first through holes 11 that communicate with the receiving cavity 2. Air supplied by the fan enters the first cavity 10 of the air duct 6 through the rotary joint 9, and is then evenly dispersed into the soil pile through the first through holes 11, achieving synergistic mixing and oxygen supply. The rotary joint 9 maintains a sealed air passage during relative rotation, allowing the rotating air duct 6 to continuously receive air, thereby delivering oxygen to the deeper layers of the pile. When the auger 5 is turning the soil, it transports the heavier petroleum components from the bottom upwards, promoting the homogenization of pollutant concentration and thus improving the efficiency of microbial degradation.

[0032] Clearly, the composting tank 1, through its containment chamber 2, provides a closed space for the oil-contaminated soil, effectively maintaining stable temperature and humidity inside the compost, thus preventing external environmental fluctuations from interfering with microbial metabolic activities and inhibiting the unorganized diffusion of volatile organic compounds, thereby reducing the risk of secondary pollution. The feed inlet 3 is located at the top or side of the composting tank 1, facilitating the addition of contaminated soil, nutrients, and microbial agents to improve the contact efficiency between microorganisms and pollutants. The discharge outlet 4 is located at the bottom or lower side of the composting tank 1, enabling the directional discharge of treated soil after the remediation cycle is completed, thereby reducing material residue and shortening batch cleaning time. In the mixing and oxygenation device, the auger 5 continuously rotates and agitates the soil within the containment chamber 2, breaking up soil aggregates and preventing material compaction, thus increasing the contact surface area between microorganisms and pollutants. The driven gear 8, located outside the containment chamber 2, is connected to the power source, preventing lubricating oil or mechanical wear products from entering the containment chamber 2 and causing secondary soil pollution. During the turning process, the auger 5 transports the heavier petroleum components from the bottom upwards, promoting the homogenization of pollutant concentration throughout the pile and thus improving the efficiency of microbial degradation. The air duct 6 extends along the axis of the auger 5 and rotates synchronously with it. It is connected to an external fan through a rotary joint 9, allowing air to pass through the first cavity 10 of the air duct 6 and then be evenly distributed into the soil pile through multiple first through holes 11. This achieves the coordinated operation of turning and oxygen supply, enabling oxygen to reach the deep areas of the pile to avoid oxygen-deficient zones. At the same time, the through holes of the air duct 6 are not easily blocked by wet soil during rotation, maintaining long-term ventilation performance.

[0033] In this embodiment, preferably, a plurality of air-guiding branch pipes 12 are connected to the first through hole 11. The plurality of air-guiding branch pipes 12 are distributed at intervals along the spiral extension path of the auger 5. The air-guiding branch pipes 12 extend radially outward along the auger 5. Each air-guiding branch pipe 12 is provided with a second through hole 13, which extends radially along the air-guiding branch pipe 12 and connects the second cavity 14 of the air-guiding branch pipe 12 and the receiving cavity 2. During the turning process, the auger 5 drives the air-guiding pipes 6 and the air-guiding branch pipes 12 to rotate synchronously. The turning action causes the soil to be continuously lifted, broken and remixed. The air-guiding branch pipes 12 are distributed at intervals along the spiral and extend radially. The second through hole 13 discharges air radially. The air is quickly dispersed to various areas of the pile under the action of rotational centrifugal force and soil turning. The material flow path formed by turning the pile intertwines with the airflow discharged from the air guide branch pipe 12. The airflow is released sequentially at different heights and radial depths as the auger rotates, thus covering the entire space from the center to the edge and from the bottom to the top of the pile. This synergistic effect ensures that oxygen is no longer confined to the vicinity of localized air supply points, but is evenly carried throughout the pile as the soil is continuously turned, avoiding oxygen-depleted areas caused by soil compaction or particle stratification. The radial extension of the air guide branch pipe 12 further increases the airflow penetration depth, ensuring that even the denser bottom soil receives sufficient oxygen. This comprehensive oxygen supply provides a stable aerobic environment for microorganisms, promoting the aerobic degradation of petroleum hydrocarbon pollutants. Simultaneously, the turning action continuously renews the soil surface, preventing microbial aging and the accumulation of metabolic products.

[0034] It is understandable that, as a better implementation, a one-way valve can be installed in the air guide branch pipe 12. The one-way valve only allows air to flow from the branch pipe to the soil, preventing backflow and blockage of the branch pipe by high-moisture soil when the machine is stopped. Alternatively, a microporous hydrophobic membrane can be wrapped around the second through hole 13. The hydrophobic membrane allows air to pass through but blocks moisture and fine particles, keeping the through hole unobstructed during long-term operation.

[0035] In this embodiment, preferably, multiple second through holes 13 are provided, distributed along the axial direction of the air guide branch pipe 12, and facing the bottom of the receiving cavity 2. The diameter of the second through holes 13 is smaller than that of the first through hole 11. The multiple second through holes 13 distributed axially on each air guide branch pipe 12 facing the bottom of the receiving cavity 2 allow the airflow to be sprayed vertically downwards onto the lower layer of soil, overcoming the oxygen deficiency problem in the lower layer caused by soil compaction due to its own weight. Since the diameter of the second through holes 13 is smaller than that of the first through hole 11, the airflow velocity increases when passing through the small holes, forming a high-kinetic-energy jet that can penetrate damp, compacted aggregates and push oxygen to a greater distance. The downward-facing arrangement of the through holes also has an anti-clogging effect. This is because soil particles are less likely to fall into the vertical or upward-facing orifices under gravity, while the downward-spraying airflow continuously sweeps the outer edge of the orifice, preventing the adhesion and accumulation of wet soil or fine particles, thereby maintaining the unobstructed flow of the through holes during long-term operation. The downward-facing high-speed jet forms a reverse contact with the soil turned up by the spiral auger 5, further enhancing gas-solid mixing and thus establishing a three-dimensional oxygenation network from bottom to top inside the pile, significantly improving the oxygen supply depth and distribution uniformity.

[0036] In this embodiment, preferably, the sidewall of the composting tank 1 is provided with multiple electrode rods 15, which are spaced apart along the axial and / or circumferential direction of the composting tank 1. The electrode rods 15 are used to collect electrons generated during the microbial degradation of petroleum pollutants and transmit them outward. The electrode rods 15 can be flexible graphite brush electrodes, composed of multiple flexible graphite fiber bundles. The fiber bundles are fixed to an insulating support plate on the inner wall of the composting tank 1, with the free ends of the fibers extending into the soil. Graphite has good conductivity and chemical inertness, enabling it to efficiently adsorb electrons released by microorganisms and export them through a busbar. Alternatively, a pluggable metal probe net can be used, with sealed ports at different heights of the composting tank 1. When in use, a metal probe can be inserted, with an electrode at the tip. The open circuit potential change at each point is monitored by a multi-channel potential recorder to infer the degradation activity. During the aerobic degradation of petroleum hydrocarbons by microorganisms, microbial metabolic activities generate electrons. The electrode rods 15 collect these electrons through physical contact and transmit them outward, thereby converting the metabolic energy of the microorganisms into measurable electrical signals or exporting them for utilization. The axial and circumferential spacing of the electrode rods 15 ensures effective electron collection at different heights and horizontal positions within the reactor stack, avoiding blind spots caused by local differences in microbial activity. Simultaneously, the multi-point arrangement increases the total amount of electrons collected. By continuously transmitting electrons outward, the metabolic activity of microorganisms within the reactor stack can be monitored in real time, providing a basis for determining the degradation stage and adjusting process parameters. On the other hand, electron removal helps maintain the smooth flow of the extracellular electron transport chain in microorganisms, preventing feedback inhibition of the metabolic process by electron accumulation, thereby promoting the oxidative decomposition efficiency of petroleum hydrocarbon pollutants. Overall, this electrode rod 15 structure achieves non-destructive monitoring and metabolic promotion of the microbial remediation process through the acquisition and extraction of bioelectrical signals.

[0037] In this embodiment, preferably, multiple electrode rods 15 are arranged at intervals along the axial direction of the compost tank 1. Multiple electrode rods 15 located at the same horizontal height constitute a group of isotropic electrode groups. Adjacent groups of electrode groups have different polarities and are electrically connected by wires 16. Electrons generated by microorganisms during the degradation of petroleum pollutants are collected by the electrode rods 15. Since adjacent electrode groups have opposite polarities, electrons move directionally from the negative pole to the positive pole in the wires 16, forming a continuous weak current. This current can stimulate the extracellular electron transfer activity of surrounding microorganisms and promote the oxidative decomposition of petroleum hydrocarbons. The alternating polarity electric field also produces a weak ion migration effect in the soil, causing nutrients and degradation products to undergo slow convection diffusion within the compost pile, thereby improving the material exchange conditions in local metabolic inhibition zones. The axially distributed electrode groups ensure that microorganisms at different height levels are electrically stimulated, avoiding stratification of biological activity caused by soil compaction or differences in oxygen supply. The parallel arrangement of multiple electrode rods 15 within the isotropic electrode groups expands the electron collection area on the same horizontal plane and improves the stability of the current output. The alternating polarity design prevents the accumulation of ion polarization caused by long-term unidirectional electric field action, maintaining the dynamic balance of the electrochemical environment. This electrode arrangement, by constructing a vertically alternating electric field, achieves synergistic enhancement and homogenization of the electrochemical degradation process within compost tank 1.

[0038] In this embodiment, preferably, the conductor 16 is equipped with a sensor 17 and a power supply. The sensor 17 is used to detect the current flowing through the conductor 16, and the power supply is used to provide driving force for electron transport. By monitoring current changes in real time, the sensor 17 can reflect the activity level of electron release during the microbial degradation of petroleum pollutants. When the current increases, it indicates vigorous microbial metabolism, and conversely, it indicates decreased degradation activity, thus providing online monitoring basis for process personnel to judge the state of bioreaction inside the reactor. The power supply applies an external voltage to the conductor 16, providing additional driving force for the directional migration of electrons from the negative electrode to the positive electrode, overcoming the problem of slow electron transport caused by the limited electrogenic capacity of microorganisms, accelerating the transfer rate of electrons between electrode groups, thereby promoting the smooth flow of the extracellular electron transport chain of microorganisms and enhancing the oxidation and decomposition efficiency of petroleum hydrocarbon pollutants. When the sensor 17 and the power supply work together, the stable current provided by the power supply allows the sensor 17 to obtain a clearer current signal with less fluctuation, improving the accuracy of detection; at the same time, the signal fed back by the sensor 17 can be used to adjust the output parameters of the power supply to achieve closed-loop control of the electrical stimulation intensity. This arrangement enables the electrode system to perform both monitoring and control functions, improving the intelligence level and degradation efficiency of the microbial composting process.

[0039] In this embodiment, preferably, the compost tank 1 has a filter layer 18 and a filtrate outlet 19 at its bottom. The filter layer 18 is used to prevent soil particles from entering the filtrate outlet 19. The inner bottom wall of the compost tank 1 is inclined, and the filtrate outlet 19 is located on the lowest side of the inner bottom wall. The inclined inner bottom wall and the location of the filtrate outlet 19 on the lowest side allow gravity to automatically collect the leachate at the outlet for discharge, preventing liquid accumulation at the bottom of the tank from creating a localized anaerobic environment or inhibiting microbial activity. This structure helps maintain a suitable moisture content inside the compost pile by timely removal of excess water, preventing soil compaction or blockage of ventilation holes due to excessive moisture. Simultaneously, the inclined bottom wall reduces cleaning dead zones, making the drainage process more thorough. The filter layer 18 can have a three-layer structure: a bottom layer of coarse gravel, a middle layer of fine sand, and an upper layer of stainless steel wire mesh, filtering particles of different sizes in stages. A U-shaped water seal pipe can be installed at the filtrate outlet 19 to prevent external air from being drawn back into the tank and disrupting the aerobic environment. Overall, the combination of the filter layer 18 and the inclined bottom wall improves the drainage performance and moisture distribution uniformity of the compost tank 1, providing a stable humidity environment for microbial metabolism.

[0040] It is understood that, as a better implementation method, a siphon-type automatic drainage device can be used. This device includes a suction pipe that is vertically inserted into the bottom of the compost tank 1 and an external drainage pipe. The bottom of the suction pipe is open and wrapped with a filter screen. The highest point of the drainage pipe is higher than the top of the suction pipe. When the liquid level rises to the highest point of the drainage pipe, a siphon effect is generated to automatically discharge the leachate. When the liquid level drops, the siphon is interrupted, realizing intermittent automatic drainage.

[0041] In this embodiment, preferably, the discharge port 4 is located at the bottom of the composting tank 1. The discharge port 4 is equipped with a valve 20, which is detachably connected to the composting tank 1 to control the opening or closing of the discharge port 4. The top surface of the valve 20 smoothly transitions to the inner bottom wall of the composting tank 1 to avoid soil residue and guide the filtrate to the filtrate outlet 19. The detachable connection of the discharge port 4 valve 20 facilitates disassembly, cleaning, or replacement of the sealing components after the repair cycle, avoiding seal failure or blockage caused by long-term contact with corrosive leachate. The smooth transition between the top surface of the valve 20 and the inner bottom wall of the composting tank 1 prevents soil particles from accumulating at the valve edge during turning, while guiding the leachate smoothly to the filtrate outlet 19 located on the lowest side, preventing liquid residue. This structure opens the valve 20 during discharge, and the treated soil is discharged by gravity without the need for additional cleaning tools, improving discharge efficiency. The detachable design also allows for individual replacement of the valve 20 in case of failure, reducing maintenance costs. The smooth-transition top surface, combined with the sloping inner bottom wall, ensures that there is almost no residual material at the bottom of the tank after each discharge, reducing the risk of cross-contamination between batches and preventing residual soil from decaying and affecting the microbial activity of the next batch.

[0042] In this embodiment, preferably, the composting tank 1 is also connected to an exhaust pipe 21, which is located at the top of the composting tank 1 and is used to discharge the waste gas generated during the microbial degradation process. The exhaust pipe 21, located at the top of the composting tank 1, utilizes the high temperature and low density of the waste gas generated during microbial degradation to allow the waste gas to rise naturally and be discharged in a concentrated manner, preventing harmful gases from accumulating in the upper part of the containment cavity 2 and polluting the operating environment. The connecting function of the exhaust pipe 21 also maintains the pressure balance between the inside of the composting tank 1 and the outside, preventing the accumulation of gas from increasing the internal pressure and inhibiting the aerobic metabolic activity of microorganisms. By promptly guiding the waste gas away, the toxic effects of hydrogen sulfide, ammonia, and volatile organic compounds on the microbial population inside the compost pile are reduced, while the possibility of waste gas condensing and flowing back to the soil surface is also reduced, thereby protecting the biological activity of the compost surface. This structure also facilitates connecting the outlet of the exhaust pipe 21 to a subsequent waste gas treatment device, achieving centralized purification of polluted gases and avoiding secondary pollution diffusion during the remediation process.

[0043] In this embodiment, preferably, the microbial composting treatment device for petroleum-contaminated soil further includes a control unit, a temperature sensor 17, a humidity sensor 17, and a dissolved oxygen sensor 17. The temperature sensor 17, humidity sensor 17, and dissolved oxygen sensor 17 are respectively connected to the control unit via signal connections. All three sensors are housed within the receiving cavity 2. The control unit controls the operation of the blower and the power source based on the detection signals from each sensor 17. The temperature sensor 17 monitors the degree of heat accumulation during biological fermentation within the compost pile, the humidity sensor 17 reflects changes in soil moisture content, and the dissolved oxygen sensor 17 determines the balance between oxygen consumption and supply. The control unit automatically adjusts the start / stop and speed of the blower, as well as the operating time and direction of the power source, based on a preset threshold and a comparison with real-time signals, so that the oxygen supply intensity and turning frequency dynamically adapt to the metabolic needs of the microorganisms. This closed-loop control structure avoids the lag and inaccuracy of manual, experience-based adjustments. It can increase fan operation to remove excess heat when the compost temperature is too high, prompt for water replenishment or reduction of ventilation when humidity is low, and promptly increase stirring and aeration when dissolved oxygen levels drop, thus maintaining a suitable growth and metabolic environment for microorganisms. The sensors 17 are distributed at different heights and radial positions, allowing the control unit to obtain the three-dimensional parameter distribution of the compost pile, preventing local anomalies from being overlooked. Overall, this control system achieves automated and precise control of the composting process through real-time feedback of multiple parameters, improving remediation efficiency and operational stability.

[0044] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of those different embodiments or examples.

[0045] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "a plurality of" means two or more, unless otherwise explicitly specified.

[0046] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any person skilled in the art can easily conceive of various variations or substitutions within the technical scope disclosed in this application, and these should all be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A microbial composting treatment device for petroleum-contaminated soil, characterized in that, include: A composting tank (1) has a receiving cavity (2) for containing petroleum-contaminated soil. The composting tank (1) is provided with an inlet (3) and an outlet (4), and the inlet (3), the receiving cavity (2) and the outlet (4) are connected in sequence. The stirring and oxygenating device includes a spiral auger (5) and an air guide pipe (6). The spiral auger (5) is located inside the receiving cavity (2) and is rotatably connected to the composting tank (1). A driven gear (8) is provided at the bottom of the spiral auger (5). The driven gear (8) is located outside the receiving cavity (2) and is used to drive the power source. The air guide pipe (6) extends along the axial direction of the spiral auger (5). The first cavity (10) of the air guide pipe (6) is connected to the air inlet (7) of the air guide pipe (6). The air inlet (7) of the air guide pipe (6) is used to connect to the air outlet pipe of an external fan through a rotary joint (9). The air guide pipe (6) is provided with multiple first through holes (11) that are connected to the receiving cavity (2). The two ends of the first through holes (11) are respectively connected to the receiving cavity (2) and the first cavity (10) of the air guide pipe (6).

2. The microbial composting treatment device for petroleum-contaminated soil according to claim 1, characterized in that, Multiple air guide pipes (12) are connected to the first through hole (11). The multiple air guide pipes (12) are distributed at intervals along the spiral extension path of the spiral auger (5). The air guide pipes (12) extend outward along the radial direction of the spiral auger (5). The air guide pipes (12) are provided with a second through hole (13). The second through hole (13) extends radially along the air guide pipe (12) and connects the second cavity (14) of the air guide pipe (12) and the receiving cavity (2).

3. A microbial composting treatment device for petroleum-contaminated soil according to claim 2, characterized in that, The second through hole (13) is provided in multiple ways. The multiple second through holes (13) are distributed along the axial direction of the air guide branch pipe (12). The second through holes (13) are arranged facing the bottom of the receiving cavity (2). The diameter of the second through hole (13) is smaller than the diameter of the first through hole (11).

4. A microbial composting treatment device for petroleum-contaminated soil according to claim 1, characterized in that, The composting tank (1) is provided with a plurality of electrode rods (15) on its side wall. The plurality of electrode rods (15) are distributed at intervals along the axial and / or circumferential direction of the composting tank (1). The electrode rods (15) are used to collect electrons generated during the microbial degradation of petroleum pollutants and transmit them outward.

5. A microbial composting treatment device for petroleum-contaminated soil according to claim 4, characterized in that, Multiple electrode rods (15) are arranged at intervals along the axial direction of the composting tank (1). Multiple electrode rods (15) at the same horizontal height constitute a group of same polarity electrode groups. The polarities of two adjacent groups of electrode groups are different and they are electrically connected by wires (16).

6. A microbial composting treatment device for petroleum-contaminated soil according to claim 5, characterized in that, The conductor (16) is equipped with a sensor (17) and a power source. The sensor (17) is used to detect the current flowing through the conductor (16), and the power source is used to provide driving force for electronic transmission.

7. A microbial composting treatment device for petroleum-contaminated soil according to claim 1, characterized in that, The composting tank (1) is provided with a water filter layer (18) and a filtrate outlet (19) at the bottom. The water filter layer (18) is used to block soil particles from entering the filtrate outlet (19). The inner bottom wall of the composting tank (1) is inclined, and the filtrate outlet (19) is located on the lowest side of the inner bottom wall.

8. A microbial composting treatment device for petroleum-contaminated soil according to claim 7, characterized in that, The discharge port (4) is located at the bottom of the composting tank (1). The discharge port (4) is equipped with a valve (20). The valve (20) is detachably connected to the composting tank (1) to control the opening or closing of the discharge port (4). The top surface of the valve (20) smoothly transitions to the inner bottom wall of the composting tank (1) to avoid soil residue and guide the filtrate to the filtrate outlet (19).

9. A microbial composting treatment device for petroleum-contaminated soil according to claim 1, characterized in that, The composting tank (1) is also connected to an exhaust pipe (21), which is located at the top of the composting tank (1) and is used to discharge the waste gas generated during the microbial degradation process.

10. A microbial composting treatment device for petroleum-contaminated soil according to claim 1, characterized in that, The microbial composting treatment device for petroleum-contaminated soil further includes a control unit, a temperature sensor (17), a humidity sensor (17), and a dissolved oxygen sensor (17). The temperature sensor (17), the humidity sensor (17), and the dissolved oxygen sensor (17) are respectively connected to the control unit. The temperature sensor (17), the humidity sensor (17), and the dissolved oxygen sensor (17) are all located in the receiving cavity (2). The control unit controls the operation of the fan and the power source according to the detection signals of each sensor (17).

Images