Groundwater impervious barrier system

Abstract

The application relates to a groundwater impervious barrier system. The system comprises an impervious composite wall arranged below the ground surface for blocking the diffusion of contaminated groundwater downstream, a groundwater pumping well arranged upstream of the impervious composite wall for pumping the contaminated groundwater, a leachate regulating tank connected with the groundwater pumping well through a drainage pipeline for collecting the contaminated groundwater, a sewage collection tank connected with the groundwater pumping well through an overflow pipeline, and a sewage treatment device connected with the sewage collection tank and the leachate regulating tank. The impervious barrier system effectively avoids the overflow risk of the pumping well in the rainy season through a double-path collection and treatment mechanism, and significantly reduces the treatment cost of the contaminated groundwater and the risk of secondary environmental pollution.

Description

Technical Field

[0001] This application relates to the field of underground wastewater treatment technology, and in particular to groundwater seepage prevention and barrier systems. Background Technology

[0002] With the development of groundwater pollution prevention and control technologies, vertical seepage prevention and barrier technology has gradually become one of the important means of treating polluted groundwater in municipal solid waste landfills. This technology effectively blocks the spread of pollution and achieves the collection and treatment of polluted groundwater by constructing vertical barriers (such as grouting curtains, underground continuous walls, HDPE membranes, etc.) and combining them with groundwater pumping systems. It has the characteristics of good barrier effect and wide applicability.

[0003] In related technologies, a common approach is to place a pumping well upstream of the contaminated groundwater and install a seepage barrier downstream of the well. The pumped contaminated groundwater is then transported to a leachate equalization tank for treatment using existing leachate treatment facilities. This method can operate effectively during the non-rainy season when water volume is low, and the treatment cost is relatively controllable.

[0004] However, during the rainy season, the aforementioned methods are prone to overflowing due to a significant increase in groundwater volume, causing contaminated groundwater to spill out untreated and resulting in secondary pollution. Furthermore, relying solely on expanding permanent treatment facilities to cope with seasonal water surges would substantially increase construction and operating costs, making it uneconomical, especially for landfills with low contaminant concentrations, where its applicability and sustainability are clearly insufficient. Utility Model Content

[0005] Therefore, it is necessary to provide a groundwater seepage prevention and barrier system to address the technical problems of contaminated groundwater in municipal solid waste landfills easily overflowing during the rainy season and the high cost of treatment.

[0006] A groundwater seepage prevention system for use in municipal solid waste landfills, the seepage prevention system comprising:

[0007] The anti-seepage composite wall is installed below ground level to prevent contaminated groundwater from spreading downstream;

[0008] A groundwater extraction well is installed upstream of the impermeable composite wall to extract contaminated groundwater;

[0009] The leachate equalization tank is connected to the groundwater pumping well via a drainage pipe, and is used to collect and treat contaminated groundwater;

[0010] The wastewater collection tank is connected to the groundwater pumping well via an overflow pipe;

[0011] The wastewater treatment device is connected to the wastewater collection tank and the leachate equalization tank.

[0012] In one embodiment, the seepage barrier system further includes:

[0013] A leachate drainage pipe is connected to the leachate equalization tank to guide contaminated surface water from the municipal solid waste landfill into the leachate equalization tank.

[0014] In one embodiment, the impermeable composite wall is disposed on the opposite waterproof layer of the municipal solid waste landfill.

[0015] In one embodiment, the groundwater pumping well is partially located below ground level and partially exposed above ground level, with a cofferdam structure surrounding the exposed portion.

[0016] In one embodiment, the inlet of the overflow pipe is located within the cofferdam structure, and the overflow pipe is used to guide the overflowing contaminated groundwater into the sewage collection tank.

[0017] In one embodiment, the impermeable composite wall is made of impermeable material.

[0018] In one embodiment, the impermeable material comprises an HDPE membrane.

[0019] In one embodiment, a submersible pump is installed inside the well pipe of the groundwater pumping well. The submersible pump is used to extract and lift contaminated groundwater and transport it to the leachate conditioning tank through the drainage pipe.

[0020] In one embodiment, the drainage pipe is connected to the well pipe, and a first pumping device is provided on the drainage pipe.

[0021] In one embodiment, the wastewater treatment device is a disc tube reverse osmosis system.

[0022] The aforementioned groundwater seepage prevention and barrier system, by setting up a dual-channel structure that combines conventional pumping and rainy season overflow drainage, as well as drainage pipes and overflow pipes, and coupling them with sewage treatment devices, can effectively prevent secondary pollution caused by overflow from pumping wells when the groundwater volume increases during the rainy season, and significantly reduce the long-term operating costs of groundwater remediation in landfills. Attached Figure Description

[0023] Figure 1 A schematic diagram illustrating the working principle of a groundwater seepage prevention and barrier system provided in one embodiment of this application.

[0024] The reference numerals in the detailed embodiments are as follows:

[0025] 100. Municipal solid waste landfill; 200. Contaminated groundwater; 110. Relative impermeable layer;

[0026] 10. Impermeable composite wall; 20. Groundwater pumping well; 30. Leachate regulating tank; 40. Sewage collection tank; 50. Sewage treatment device; 60. Leachate drainage pipe;

[0027] 21. Drainage pipe; 22. Overflow pipe; 23. Cofferdam structure; 24. Well casing. Detailed Implementation

[0028] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application are described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0029] In the description of this application, it should be understood that if terms such as "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" appear, these terms indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0030] Furthermore, where the terms "first" and "second" appear, these terms are 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 with "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, where the term "multiple" appears, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0031] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0032] In this application, unless otherwise expressly specified and limited, the use of descriptions such as "above" or "below" the second feature indicates that the first and second features are in direct contact or indirect contact via an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. Similarly, "below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0033] It should be noted that if an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening element. If an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. If so, the terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used in this application are for illustrative purposes only and do not represent the only possible implementation.

[0034] See Figure 1 , Figure 1 This diagram illustrates the working principle of a groundwater seepage prevention and barrier system according to an embodiment of this application. The system includes a seepage-proof composite wall 10, installed below ground level to prevent contaminated groundwater 200 from spreading downstream; a groundwater pumping well 20, located upstream of the seepage-proof composite wall 10, for pumping out the contaminated groundwater 200; a leachate regulating tank 30, connected to the groundwater pumping well 20 via a drainage pipe 21, for collecting and treating the contaminated groundwater 200; a sewage collection tank 40, connected to the groundwater pumping well 20 via an overflow pipe 22; and a sewage treatment device 50, connected to the sewage collection tank 40 and the leachate regulating tank 30.

[0035] The groundwater seepage prevention and barrier system of this application significantly improves the ability to cope with the rainy season by setting up a dual-channel collection and treatment mechanism. During the non-rainy season, when the groundwater pollution level is low, the polluted groundwater 200 is directly pumped to the leachate equalization tank 30 for treatment via the drainage pipe 21. However, when the rainy season arrives and the groundwater volume increases significantly, the polluted groundwater can be guided to the sewage collection tank 40 for temporary storage via the overflow pipe 22 to prevent untreated sewage from overflowing and causing secondary pollution.

[0036] Furthermore, the groundwater seepage prevention and barrier system also includes a wastewater treatment device 50. Since the wastewater treatment device 50 is connected to both the wastewater collection tank 40 and the leachate equalization tank 30, it can rapidly reduce the volume of low-concentration polluted groundwater temporarily stored in the wastewater collection tank 40. The clarified liquid is discharged after meeting standards, while the concentrated liquid is returned to the leachate equalization tank 30 for further treatment. During the rainy season, the wastewater treatment device 50 can be leased in advance and connected to the groundwater seepage prevention and barrier system. This design not only effectively solves the problems of rainy season overflow and insufficient treatment capacity in traditional systems but also significantly reduces the economic burden on landfill operators in terms of equipment investment and long-term operation and maintenance. It is particularly suitable for groundwater treatment scenarios in municipal solid waste landfills with low pollutant concentrations and large seasonal fluctuations in water volume.

[0037] It should be noted that the leachate equalization tank 30 is typically designed with sufficient volume to accommodate the shock loads caused by water volume fluctuations during the rainy and non-rainy seasons. By rationally positioning the inlet and outlet within the leachate equalization tank 30 and utilizing the principles of natural water diffusion and sedimentation, the leachate equalization tank 30 can initially balance water quality differences, reduce peak pollutant concentrations, and provide relatively stable influent conditions for subsequent treatment processes. Furthermore, guide walls or buffer baffles can be installed within the leachate equalization tank 30 to extend the hydraulic retention time, promote the natural settling of suspended solids, and facilitate the initial degradation of some pollutants.

[0038] According to some embodiments of this application, the leachate equalization tank 30 is equipped with multi-stage liquid level sensors, which can monitor changes in the water level in the tank in real time. When the water level reaches the high limit, the system can increase the outflow from the tank; when the water level is low, the outflow is reduced to maintain the necessary equalization volume. This dynamic balancing mechanism ensures that the leachate equalization tank 30 is always kept in optimal working condition, avoiding the risk of tank overflow and ensuring the continuous and stable operation of subsequent treatment.

[0039] In one embodiment, the seepage barrier system further includes a leachate drainage pipe 60 connected to a leachate equalization tank 30, used to guide contaminated surface water from the municipal solid waste landfill 100 into the leachate equalization tank 30. By installing the leachate drainage pipe 60, the seepage barrier system can more comprehensively collect contaminated water within the landfill area, including not only groundwater but also surface runoff or accumulated water, further enhancing the overall integrity and effectiveness of pollution control. This design helps prevent the disorderly overflow or infiltration of contaminated surface water, reducing the potential pollution risk to surrounding soil and groundwater, while achieving centralized management and treatment of contaminated water, enhancing the overall environmental benefits of the system. Furthermore, the introduction of the leachate drainage pipe 60 also optimizes the system's operational efficiency. During the rainy season or when surface water volume is high, this pipe can quickly guide surface water into the leachate equalization tank 30, preventing localized water accumulation from interfering with landfill operations, and complementing the groundwater pumping system to jointly address contaminated water from different sources and with different properties.

[0040] In one embodiment, the impermeable composite wall 10 is installed on the relative impermeable layer 110 of the municipal solid waste landfill 100. By embedding or sitting the bottom of the impermeable composite wall 10 on the relative impermeable layer 110, the sealing and stability of the entire barrier system can be significantly enhanced. The relative impermeable layer 110, as a natural low-permeability stratum, effectively connects with the artificial impermeable system, forming a continuous and complete barrier. This design greatly improves the reliability of intercepting the downstream migration of contaminated groundwater. In addition, this arrangement optimizes the engineering efficiency and economy of the groundwater seepage barrier system. By relying on the existing relative impermeable layer 110, the design depth of the impermeable composite wall 10 can be appropriately reduced, reducing material usage and construction difficulty, and saving construction costs.

[0041] In one embodiment, the groundwater pumping well 20 is partially located underground and partially exposed above ground, with a cofferdam structure 23 surrounding the exposed portion. This design effectively enhances the system's ability to cope with water level fluctuations, especially during the rainy season when groundwater levels rise sharply. The cofferdam structure 23 can temporarily contain and buffer the overflow risk in the wellhead area, buying valuable time for subsequent drainage treatment. As a ground-level protective barrier, the cofferdam structure 23 not only prevents cross-contamination caused by backflow of surface runoff around the pumping well but also ensures the structural stability and operational safety of the wellhead operating area. Furthermore, when the water level rises to the height of the cofferdam structure 23, the overflow pipe 22 can promptly guide excess water to the wastewater collection tank 40, preventing untreated contaminated groundwater from overflowing into the surrounding environment and significantly reducing the risk of secondary pollution. This multi-layered protection strategy combining surface and underground protection ensures the continuity of routine pumping operations and enhances the system's resilience under extreme hydrological conditions, providing landfill operators with an economical, practical, and highly reliable rainy season operation solution.

[0042] In one embodiment, the inlet of the overflow pipe 22 is located within the cofferdam structure 23. The overflow pipe 22 is used to guide the overflowing contaminated groundwater 200 to the sewage collection tank 40. This design ensures that when the groundwater level rises abnormally and exceeds the normal operating level of the pumping well, the overflow pipe 22 can immediately activate its drainage function. Simultaneously, the inlet of the overflow pipe 22 is located inside the cofferdam structure 23, enabling it to capture the contaminated groundwater 200 overflowing from the wellhead immediately and quickly transport it to the sewage collection tank 40 for temporary storage, thereby avoiding the environmental risks caused by the contaminated water flowing onto the surface.

[0043] In one embodiment, the impermeable composite wall 10 is made of an impermeable material. This material selection is crucial to ensuring the long-term effective operation of the entire impermeable barrier system. The wall constructed of the impermeable material has an extremely low permeability coefficient, forming a reliable underground barrier that effectively prevents contaminated groundwater from migrating downstream, fundamentally controlling the spread of pollution. This material not only needs to possess excellent impermeability but also sufficient durability and chemical stability to resist corrosion, osmotic pressure changes, and long-term water pressure encountered in the complex underground environment, ensuring that the impermeable composite wall 10 maintains its complete barrier function throughout the landfill's operational lifespan.

[0044] According to some embodiments of this application, the seepage barrier material includes an HDPE membrane. HDPE (high-density polyethylene) membrane, as a widely used seepage barrier material in modern environmental engineering, provides reliable technical support for the entire seepage barrier system. This material has an extremely low permeability coefficient, effectively blocking the migration of contaminated groundwater. Simultaneously, its excellent chemical corrosion resistance ensures long-term structural integrity and seepage prevention in the complex leachate environment of landfills, avoiding seepage barrier failure due to material aging or corrosion. Furthermore, its good flexibility allows it to adapt to construction needs under different geological conditions, forming a tight connection with the relative impermeable layer 110 to construct a continuous and complete seepage barrier. Modern seepage barrier materials such as HDPE membranes are not only technologically mature and reliable, but also relatively convenient to construct, allowing for flexible design of their thickness and laying method according to site geological conditions.

[0045] In one embodiment, a submersible pump is installed inside the well pipe 24 of the groundwater pumping well 20. The submersible pump is used to extract and lift contaminated groundwater 200 and transport it to the leachate equalization tank 30 through the drainage pipe 21. The submersible pump's characteristic of being completely submerged in groundwater allows it to efficiently cope with water level fluctuations, especially during the non-rainy season when water volume is relatively low, maintaining a stable pumping efficiency and providing a reliable guarantee for the normal operation of the system. In addition, the coordinated operation of the submersible pump and the drainage pipe 21 realizes a fully enclosed process from extraction to transportation, avoiding the risk of exposure and secondary pollution of pollutants during the transfer process.

[0046] In one embodiment, the drainage pipe 21 is connected to the well pipe 24, and a first pumping device is installed on the drainage pipe 21. The first pumping device can work in tandem with the submersible pump in the well to overcome energy loss during long-distance transportation and ensure that the polluted water can reach the leachate regulating tank 30 efficiently. Especially during the non-rainy season when the water volume is low, this dual-pump configuration can be started, stopped, or have its operating parameters adjusted as needed to optimize energy consumption.

[0047] In one embodiment, the wastewater treatment unit 50 is a DTRO facility. Employing disc tube reverse osmosis (DTRO) technology as the core treatment unit of the system is an optimized choice for the characteristics of low-concentration contaminated groundwater. Thanks to its unique flow channel design and membrane separation technology, the DTRO facility can efficiently treat groundwater containing complex components such as low concentrations of organic pollutants and heavy metals. Its pollution resistance and operational flexibility are significantly superior to traditional treatment processes, making it particularly suitable for treating landfill leachate and contaminated groundwater with significant water quality fluctuations.

[0048] Furthermore, DTRO facilities can be rapidly deployed during peak rainy seasons through leasing, avoiding the financial burden of constructing permanent, high-cost treatment facilities. Their modular design allows for flexible adjustment of treatment capacity based on actual water volume, enabling an "on-demand" operation model. The clarified liquid generated during treatment can be directly discharged in compliance with standards, significantly reducing the load on subsequent treatment processes, while the concentrated liquid is returned to the leachate equalization tank 30 for further treatment, forming an efficient separate treatment process. This design not only effectively solves the problem of insufficient treatment capacity during the rainy season but also significantly reduces operating costs while ensuring treatment effectiveness, providing municipal solid waste landfill 100 with an advanced treatment solution that meets both environmental requirements and good economics.

[0049] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0050] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A groundwater seepage prevention and barrier system for use in municipal solid waste landfills, characterized in that, The seepage prevention and barrier system includes: The anti-seepage composite wall is installed below ground level to prevent contaminated groundwater from spreading downstream; A groundwater extraction well is installed upstream of the impermeable composite wall to extract contaminated groundwater; The leachate equalization tank is connected to the groundwater pumping well via a drainage pipe, and is used to collect and treat contaminated groundwater; The wastewater collection tank is connected to the groundwater pumping well via an overflow pipe; The wastewater treatment device is connected to the wastewater collection tank and the leachate equalization tank.

2. The groundwater seepage prevention and barrier system according to claim 1, characterized in that, The seepage prevention and barrier system also includes: A leachate drainage pipe is connected to the leachate equalization tank to guide contaminated surface water from the municipal solid waste landfill into the leachate equalization tank.

3. The groundwater seepage prevention and barrier system according to claim 1, characterized in that, The impermeable composite wall is installed on the relative waterproof layer of the municipal solid waste landfill.

4. The groundwater seepage prevention and barrier system according to claim 1, characterized in that, The groundwater pumping well is partially located below ground level and partially exposed above ground level, with a cofferdam structure surrounding the exposed portion.

5. The groundwater seepage prevention and barrier system according to claim 4, characterized in that, The inlet of the overflow pipe is located within the cofferdam structure, and the overflow pipe is used to guide the overflowing contaminated groundwater into the sewage collection tank.

6. The groundwater seepage prevention and barrier system according to claim 1, characterized in that, The impermeable composite wall is made of impermeable materials.

7. The groundwater seepage prevention and barrier system according to claim 6, characterized in that, The impermeable material includes an HDPE membrane.

8. The groundwater seepage prevention and barrier system according to claim 1, characterized in that, The well pipe of the groundwater pumping well is equipped with a submersible pump, which is used to extract and lift the contaminated groundwater and transport it to the leachate regulating tank through the drainage pipeline.

9. The groundwater seepage prevention and barrier system according to claim 8, characterized in that, The drainage pipe is connected to the well pipe, and a first pumping device is installed on the drainage pipe.

10. The groundwater seepage prevention and barrier system according to claim 1, characterized in that, The wastewater treatment device is a disc tube reverse osmosis system.

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