Landfill leachate pretreatment system

Abstract

The utility model provides a landfill leachate pretreatment system which comprises a primary settling tank, a sand filter tank, a pH adjusting tank and an effluent storage tank which are sequentially connected along the flow direction of leachate, a control console and a water inlet pump are arranged on a water outlet pipeline of the primary settling tank, an electric valve of the control console is linked with the sand filter tank, and the water inlet pump is connected with a water inlet of the sand filter tank; the pH adjusting tank is connected with a water inlet of the effluent storage tank through an overflow pipeline; and the primary settling tank, the sand filtering tank, the pH adjusting tank and the effluent storage tank are respectively connected to the dehydration supernatant pool through emptying pipelines. The device is simple and reasonable in structure and high in integrity, the primary settling tank, the sand filtering tank, the pH adjusting tank and the effluent storage tank are designed cooperatively, and leachate is purified in a stepped mode; the primary settling tank reduces the follow-up treatment load; the sand filter tank provides high-quality inlet water for the reverse osmosis system; the pH adjusting tank prevents water quality fluctuation from damaging a membrane system; the pretreated percolate meets the reverse osmosis water inlet standard, membrane pollution is reduced, and efficient operation of reverse osmosis deep treatment is guaranteed.

Description

Technical Field

[0001] This utility model relates to the field of landfill leachate treatment technology, and more specifically, to a landfill leachate pretreatment system. Background Technology

[0002] Landfill leachate primarily originates from the water content of the waste itself and atmospheric precipitation such as rain and snow. Leachate exhibits high pollutant concentrations, complex compositions, and significant treatment challenges. As landfills age, the organic matter content of the leachate decreases annually, while ammonia nitrogen concentrations increase. Leachate from aging landfills is characterized by complex composition, high suspended solids and ammonia nitrogen concentrations, but extremely low levels of biodegradable organic matter. In many areas, the ammonia nitrogen concentration in leachate from landfills older than 10 years can reach over 3000 mg / L, with an imbalanced C / N ratio and poor biodegradability.

[0003] Existing methods for treating leachate from aging landfills using biochemical systems require the addition of large amounts of external carbon sources, significantly increasing treatment costs.

[0004] Furthermore, traditional leachate pretreatment processes primarily remove particulate matter from water by adding flocculants. The flocculant aggregates with the particles in the water to form larger flocs. As the floc density gradually increases, these flocs, exceeding the density of water, gradually settle to the bottom, forming sludge. After settling and stratification, the water at the top is drained, and the floc sediment is then collected and cleaned. However, the formation of stable flocs is generally time-consuming, and the formation and settling of flocs are difficult to control, sometimes leading to floc breakage and redispersal in the water. This increases not only the material cost of the flocculant itself but also subsequent cleaning costs. In subsequent reverse osmosis membrane systems, the use of flocculants also increases the risk of membrane fouling, making it difficult to meet the feed water requirements of the reverse osmosis membrane system. This leads to increased membrane module fouling, decreased treatment efficiency, shortened membrane lifespan, and even affects the final effluent's compliance with discharge standards. Utility Model Content

[0005] Therefore, the purpose of this utility model is to propose a landfill leachate pretreatment system. Through the coordinated design of a primary sedimentation tank, sand filter tank, pH adjustment tank, and effluent storage tank, it achieves step-by-step purification of the leachate: the primary sedimentation tank removes large suspended solids through sedimentation, reducing the load on subsequent treatment processes; the sand filter tank utilizes the interception, sedimentation, and adsorption effects of quartz sand to remove suspended solids larger than 40 microns and some organic matter, providing high-quality feed water for the reverse osmosis system; the pH adjustment tank automatically maintains the effluent pH at a stable 6-7, avoiding damage to the membrane system from water quality fluctuations; this ensures that the pretreated leachate meets the reverse osmosis feed water standards, reduces membrane fouling, extends the service life of membrane modules, and improves the system's shock resistance, thereby guaranteeing the efficient operation of deep reverse osmosis treatment and ultimately achieving stable, compliant discharge of leachate; furthermore, it adopts PLC linkage control and modular design, resulting in a high degree of automation, convenient operation, low maintenance costs, improved efficiency of front-end pretreatment of leachate from aging landfills, and enhanced cost-effectiveness of the treatment system.

[0006] This utility model provides a landfill leachate pretreatment system, comprising: a primary sedimentation tank, a sand filter tank, a pH adjustment tank, and an effluent storage tank connected sequentially along the leachate flow direction. The effluent outlet pipe of the primary sedimentation tank is equipped with a control console and an inlet pump. The electric valve of the control console is linked to the sand filter tank, and the inlet pump is connected to the inlet of the sand filter tank. The pH adjustment tank is connected to the inlet of the effluent storage tank through an overflow pipe. The primary sedimentation tank, sand filter tank, pH adjustment tank, and effluent storage tank are each connected to a dewatering supernatant tank through a drain pipe.

[0007] This utility model discloses a leachate pretreatment system for pretreating effluent from the equalization tank of aging landfills. The effluent then enters a reverse osmosis membrane system for further treatment, ultimately achieving compliant discharge. Through the coordinated design of the primary sedimentation tank, sand filter tank, pH adjustment tank, and effluent storage tank, the pretreatment process is optimized, overcoming the bottleneck in leachate treatment efficiency in aging landfills and achieving the goal of high-efficiency and low-consumption pretreatment.

[0008] The electric valve on the control panel controls the flow of leachate into or stops it from entering the sand filter tank.

[0009] In one embodiment of this utility model, the primary sedimentation tank is made of 10 tons of PE material, with a diameter of φ2250mm and a height of 2.4 meters. The height of the inlet of the primary sedimentation tank is 0.5 meters, and the height of the outlet is 1.5 meters.

[0010] After entering the sand filter tank, the leachate undergoes further removal of impurities and some organic matter through the interception, sedimentation, and adsorption of the filter media. The leachate treated by the sand filter tank can effectively retain suspended solids larger than 40 microns, and the treated effluent is pumped to the pH adjustment tank.

[0011] Preferably, the inlet pressure of the inlet pump is controlled between 0.2 and 0.4 MPa; the inlet pump is equipped with a low liquid level protection function.

[0012] Preferably, the sand filter tank is equipped with an automatic backwashing function every day, with a backwashing time of 1 hour.

[0013] In one embodiment of this utility model, the sand filter tank is made of fiberglass and has a size of Φ1200*2350mm. It is filled with quartz sand with a particle size of 0.5-1mm.

[0014] Specifically, the pH adjustment tank consists of a 5-ton container, which is supported by a bracket at the bottom. A pH probe is installed at the top of the pH adjustment tank, extending into the upper 1 / 3 of the tank. The water from the pH adjustment tank overflows into the water storage tank through two pipes.

[0015] Furthermore, the inlet of the primary sedimentation tank is located at the bottom of the tank body, and the outlet is located in the middle of the tank body; the outlet pipe of the primary sedimentation tank is divided into two paths, one path is connected to the sand filter tank, and the other path is connected to the dewatering supernatant tank through a pipe; a sludge outlet is provided at the bottom of the primary sedimentation tank.

[0016] Specifically, the control panel includes two types of electric valves: one for the sand filter tank and the other for the dewatering supernatant tank. The electric valve for the sand filter tank controls the flow of leachate into or out of the sand filter tank via a connecting outlet pipe. When the sand filter tank stops operating, the electric valve for the sand filter tank closes, and the electric valve for the dewatering supernatant tank opens, controlling the flow of leachate into or out of the dewatering supernatant tank via a connecting outlet pipe.

[0017] When the liquid level in the primary settling tank reaches the middle, the leachate flows out from the outlet of the primary settling tank and is pumped to the sand filter tank for treatment. The drain outlet discharges the settled wastewater from the tank, and the settled effluent enters the sand filter tank for secondary filtration.

[0018] Furthermore, the inlet of the sand filter tank is located at the upper part of the tank body, and the outlet is located at the lower part of the tank body. The inside of the sand filter tank is filled with filter media for removing impurities and some organic matter from the leachate, and the filter media occupies a part of the volume of the sand filter tank body.

[0019] The water inlet mode of the sand filter tank is top inlet and bottom outlet. When the water entering from the top passes through the sand filter layer, impurities will be trapped on the filter layer, which more effectively removes impurities such as suspended solids, silt and organic matter in the water. The leachate after secondary filtration in the sand filter tank flows from the bottom to the pH adjustment tank for pH adjustment.

[0020] Preferably, the filter media is quartz sand. In one embodiment of the present invention, the particle size of the quartz sand is 0.5-1.2 mm, and the filling amount of the quartz sand is 1 / 2 of the tank volume of the sand filter tank.

[0021] Quartz sand effectively filters water by removing suspended solids, silt, colloidal particles, and other impurities, reducing turbidity and improving clarity.

[0022] The negative charge on the surface of quartz sand can adsorb organic matter, some heavy metal ions (such as iron and manganese), and pesticide residues in the water, further purifying the water quality.

[0023] Quartz sand filters can trap microorganisms and bacteria in water, reducing biological pollution and improving water safety.

[0024] Furthermore, a hydrochloric acid diaphragm pump is connected to the outside of the pH adjusting tank; a stirrer is provided on the upper part of the outside of the pH adjusting tank, and a stirring device is provided on the bottom side of the inside of the pH adjusting tank, with the stirrer driving the stirring device.

[0025] The pH adjustment tank automatically adds hydrochloric acid via a hydrochloric acid diaphragm pump to adjust the pH value to between 6 and 7 (other pH ranges can also be set according to actual needs).

[0026] The stirrer drives the stirring device to rotate and stir, so that the leachate in the pH adjustment tank is evenly mixed and the pH value of the leachate is quickly adjusted to the set range.

[0027] Furthermore, the inlet of the water storage tank is located at the top of the tank body, and the outlet is located at the bottom of the tank body; the top of the water storage tank body is provided with an overflow pipe, and the bottom of the tank body is provided with a drain valve, which is connected to the drain pipe.

[0028] The leachate, after its pH value has been adjusted by the pH adjustment tank, flows into the effluent storage tank via overflow.

[0029] In one embodiment of this utility model, the effluent storage tank is a 10-ton container with top inlet and bottom outlet. The inlet height is 2.3 meters, and the outlet height is 0.5 meters. An overflow pipe prevents overcapacity overflow due to excessive water production. The drain valve is located 0.5 meters from the bottom, and the leachate is discharged through a ditch to the dewatering supernatant tank, and finally returned to the equalization tank.

[0030] Furthermore, the primary sedimentation tank is equipped with a high level gauge and a low level gauge, which are respectively set at the high level and low level inside the primary sedimentation tank.

[0031] The level gauge uses high-precision sensors or magnetic coupling and other measurement technologies to acquire real-time data on the height of leachate in the primary sedimentation tank, enabling real-time dynamic monitoring, precise control of inflow and outflow, and optimization of leachate storage in the tank.

[0032] Furthermore, flow meters for real-time monitoring of the inlet flow rate are installed on both the inlet and outlet pipes of the primary sedimentation tank.

[0033] Preferably, a volumetric flow meter is selected. Volumetric flow meters have high measurement accuracy, are unaffected by installation pipeline conditions, and have a wide measurement range. As a direct-reading instrument, a volumetric flow meter can directly obtain the cumulative total without external power, providing clear and concise results and easy operation.

[0034] Furthermore, the primary sedimentation tank is connected to a bag filter, and the outlet of the bag filter is connected to the inlet of the primary sedimentation tank via a flow meter on the inlet pipe of the primary sedimentation tank.

[0035] The bag filter performs preliminary filtration of the incoming water, which then enters the primary sedimentation tank for the sedimentation of large suspended solids.

[0036] Preferably, the filter media of the bag filter includes PE, PP, and PTFE.

[0037] In one embodiment of this utility model, the filtration accuracy of the bag filter is 100 micrometers.

[0038] Furthermore, a sand filter variable frequency water inlet pump is installed on one of the water outlet pipes from the primary sedimentation tank into the sand filter tank, and the sand filter variable frequency water inlet pump is connected to the sand filter tank.

[0039] The effluent from the primary sedimentation tank is transported to the sand filter tank by a variable frequency inlet pump for secondary filtration.

[0040] Preferably, there are two sand filter variable frequency water inlet pumps, one of which is in use and the other is in standby mode. In one embodiment of this utility model, the flow rate of each sand filter variable frequency water inlet pump is Q=15m³ / h.

[0041] Furthermore, the landfill leachate pretreatment system also includes a control system, which is electrically connected to the pumps, valves, pH probes, hydrochloric acid diaphragm pumps, and level gauges installed or connected to the primary sedimentation tank, sand filter tank, pH adjustment tank, effluent storage tank, and bag filter, respectively. The control system includes a PLC controller.

[0042] Specifically, the electrical components of the entire landfill leachate pretreatment system are controlled by a PLC controller (programmable logic controller), supporting both manual and automatic operation modes.

[0043] The PLC controller can adjust the influent flow rate, pH range, flushing frequency, and start / stop of the agitator. Each valve can be started independently, and all pipelines are equipped with drain valves for easy system maintenance and cleaning.

[0044] Preferably, the control system is equipped with a flowchart display interface and is operated via a touch screen, providing good human-computer interaction.

[0045] Compared with the prior art, the beneficial effects of this utility model are:

[0046] The landfill leachate pretreatment system provided by this utility model has a simple and reasonable structure with strong overall integration. Through the coordinated design of a primary sedimentation tank, a sand filter tank, a pH adjustment tank, and an effluent storage tank, it achieves step-by-step purification of the leachate: the primary sedimentation tank removes large suspended solids through sedimentation, reducing the load on subsequent treatment; the sand filter tank utilizes the interception, sedimentation, and adsorption effects of quartz sand to effectively remove suspended solids larger than 40 microns and some organic matter, providing high-quality feed water for the reverse osmosis system; the pH adjustment tank maintains a stable pH of 6-7 in the effluent through automatic control, avoiding damage to the membrane system caused by water quality fluctuations. This ensures that the pretreated leachate meets the reverse osmosis feed water standards, significantly reduces membrane fouling, extends the service life of membrane modules, improves the system's shock resistance, ensures efficient operation of deep reverse osmosis treatment, and achieves stable and compliant discharge of leachate. Furthermore, the system adopts PLC linkage control and modular design, which has advantages such as high automation, convenient operation, and low maintenance costs, improving the cost-effectiveness of the treatment system and effectively improving the pretreatment efficiency of leachate from aging landfills. Attached Figure Description

[0047] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the scope of the invention.

[0048] In the attached diagram:

[0049] Figure 1 This is a system architecture diagram of the landfill leachate pretreatment system according to an embodiment of the present invention;

[0050] Figure 2 This is a system schematic diagram of the landfill leachate pretreatment system according to an embodiment of the present invention.

[0051] The markings in the attached figure are as follows:

[0052] 1. Primary sedimentation tank; 11. Control panel; 12. Inlet pump in use; 13. Inlet pump in standby mode; 14. High level gauge; 15. Low level gauge; 16. Flow meter; 2. Sand filter tank; 3. pH adjustment tank; 31. Hydrochloric acid diaphragm pump; 32. Agitator; 33. Stirring device; 34. pH probe; 4. Effluent storage tank; 5. Drain pipe; 6. Bag filter. Detailed Implementation

[0053] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numerals in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this disclosure. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this disclosure as detailed in the appended claims.

[0054] The terminology used in this disclosure is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. The singular forms “a,” “the,” and “the” as used in this disclosure and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used herein refers to and includes any and all possible combinations of one or more of the associated listed items.

[0055] It should be understood that although the terms first, second, and third may be used in this disclosure to describe various information, such information should not be limited to these terms. These terms are used only to distinguish information of the same type from one another. For example, without departing from the scope of this disclosure, first information may also be referred to as second information, and similarly, second information may also be referred to as first information. Depending on the context, the word "if" as used herein may be interpreted as "when," "when," or "in response to determination."

[0056] Example

[0057] This utility model provides a landfill leachate pretreatment system, such as... Figure 1 , Figure 2The system includes a primary sedimentation tank 1, a sand filter tank 2, a pH adjustment tank 3, and an effluent storage tank 4, connected sequentially along the leachate flow direction. Flow meters 16 are installed on both the inlet and outlet pipes of the primary sedimentation tank 1 to monitor the inlet flow rate in real time. The primary sedimentation tank 1 is connected to a bag filter 6, and the outlet of the bag filter 6 is connected to the inlet of the primary sedimentation tank 2 via the flow meter 16 on the inlet pipe of the primary sedimentation tank 1. The bag filter 6 performs preliminary filtration of the inlet water, which then enters the primary sedimentation tank 1 for sedimentation of large suspended solids. The filtration accuracy of the bag filter 6 is 100 microns. A control console 11 is installed on the outlet pipe of the primary sedimentation tank 1. The electric valves on the control console 11 are linked to the sand filter tank 2 to control the flow of leachate into or out of the sand filter tank 2. The electric valves on the control console 11 include two types: one for the flow to the sand filter tank 2 and the other for the flow to the dewatering supernatant tank. An electric valve controlling the flow of leachate to the sand filter tank 2 via a connecting outlet pipe prevents the leachate from entering or stopping. When the sand filter tank 2 stops operating, the electric valve to the sand filter tank 2 closes, and the electric valve to the dewatering supernatant tank opens, controlling the flow of leachate to or stopping the flow of leachate into the dewatering supernatant tank via a connecting outlet pipe. Two inlet pumps (sand filter variable frequency inlet pumps) are installed on the outlet pipe from the primary sedimentation tank 1 to the sand filter tank 2. One is the inlet pump 12 in operation, and the other is the inlet pump 13 in standby mode. Both inlet pumps are connected to the sand filter tank 2, and the inlet pumps transport the effluent from the primary sedimentation tank 1 to the sand filter tank 2 for secondary filtration. The flow rate of each inlet pump is Q = 15 m³ / h. The inlet pressure of the inlet pumps is controlled between 0.2-0.4 MPa; the inlet pumps are equipped with a low-level protection function. The inlet pump is connected to the inlet of the sand filter tank 2; the pH adjustment tank 3 is connected to the inlet of the effluent storage tank 4 through the overflow pipe; the primary sedimentation tank 1, sand filter tank 2, pH adjustment tank 3, and effluent storage tank 4 are respectively connected to the dewatering supernatant tank through the drain pipe 5.

[0058] Primary sedimentation tank 1 is made of 10-ton PE material, with a diameter of φ2250mm and a height of 2.4 meters. The inlet height of primary sedimentation tank 1 is 0.5 meters, and the outlet height is 1.5 meters. After the leachate enters sand filter tank 2, impurities and some organic matter in the leachate are further removed through the interception, sedimentation, and adsorption of the filter media. Sand filter tank 2 is made of fiberglass, with dimensions of Φ1200*2350mm, and is filled with quartz sand with a particle size of 0.5-1mm. Sand filter tank 2 is equipped with an automatic backwashing function every day, with a backwashing time of 1 hour. The leachate treated by sand filter tank 2 can effectively intercept suspended solids larger than 40 microns.

[0059] The inlet of the primary sedimentation tank 1 is located at the bottom of the tank, and the outlet is located in the middle of the tank. The outlet pipe of the primary sedimentation tank 1 is divided into two lines: one line connects to the sand filter tank 2, and the other line connects to the dewatering supernatant tank via a pipe. A drain outlet is provided at the bottom of the primary sedimentation tank 1. When the liquid level in the primary sedimentation tank 1 reaches the middle of the tank, the leachate flows out from the outlet of the primary sedimentation tank 1 and is transported to the sand filter tank 2 for treatment by the inlet pump 12. The drain outlet discharges the settled wastewater from the tank, and the settled effluent enters the sand filter tank 2 for secondary filtration.

[0060] The inlet of sand filter tank 2 is located at the top of the tank body, and the outlet is located at the bottom of the tank body. The inside of sand filter tank 2 is filled with filter media to remove impurities and some organic matter from the leachate, and the filter media occupies part of the tank body volume. The filter media is made of quartz sand with a particle size of 0.5-1.2mm, and the filling amount of quartz sand is 1 / 2 of the tank body volume. The water inlet mode of sand filter tank 2 is top inlet and bottom outlet. When the water entering from the top passes through the sand filter layer, impurities are trapped on the filter layer, which more effectively removes suspended solids, silt and organic matter from the water. The leachate after secondary filtration by sand filter tank 2 flows from the bottom of sand filter tank 2 (which can be pumped) to pH adjustment tank 3, where the pH value is adjusted.

[0061] The pH adjusting tank 3 consists of a 5-ton container, elevated by a support frame at the bottom. A pH probe 34 is installed at the top of the tank, extending into the upper third of the tank. The effluent from the pH adjusting tank 3 overflows into the effluent storage tank 4 via two pipes. An external hydrochloric acid diaphragm pump 31 is connected to the pH adjusting tank 3. A stirrer 32 is located on the top of the pH adjusting tank 3, and a stirring device 33 is located on the bottom inside the tank. The stirrer 32 drives the stirring device 33 to rotate and stir, ensuring uniform mixing of the leachate within the pH adjusting tank 3 and rapidly adjusting the pH value to the set range. Hydrochloric acid is automatically added to the pH adjusting tank 3 via the hydrochloric acid diaphragm pump 31, adjusting the pH value to between 6 and 7. The leachate, after pH adjustment by the pH adjusting tank 3, overflows into the effluent storage tank 4.

[0062] The inlet of the effluent storage tank 4 is located at the top of the tank, and the outlet is located at the bottom. An overflow pipe is installed at the top of the tank, and a drain valve is installed at the bottom, connected to the drain pipe 5. The effluent storage tank 4 is a 10-ton container with top inlet and bottom outlet. The inlet height is 2.3 meters, and the outlet height is 0.5 meters. The overflow pipe prevents overcapacity overflow due to excessive water production. The drain valve is located 0.5 meters from the bottom, and the leachate is discharged through a ditch to the dewatering supernatant tank, and finally returned to the equalization tank.

[0063] The primary sedimentation tank 1 is equipped with a high-level gauge 14 and a low-level gauge 15, which are respectively positioned at the designated high and low levels within the tank. These gauges utilize high-precision sensors or magnetic coupling technology to acquire real-time data on the leachate level within the tank, enabling real-time dynamic monitoring, precise control of the influent and effluent flow rates, and optimization of leachate storage within the tank.

[0064] The landfill leachate pretreatment system in this embodiment also includes a control system, which comprises a PLC controller. The control system is electrically connected to pumps, valves, pH probes 34, hydrochloric acid diaphragm pumps 31, and level gauges installed or connected to the primary sedimentation tank 1, sand filter tank 2, pH adjustment tank 3, effluent storage tank 4, and bag filter 6. The electrical components of the entire landfill leachate pretreatment system are controlled in a coordinated manner by the PLC controller, supporting both manual and automatic operation modes. The PLC controller can adjust the influent flow rate, pH adjustment range, flushing frequency, and the start / stop of the agitator. Each valve can be started independently, and all pipelines are equipped with drain valves for easy system maintenance and cleaning.

[0065] The control system is equipped with a flowchart display interface and is operated via a touch screen, providing excellent human-computer interaction.

[0066] The leachate pretreatment system in this embodiment is used to pretreat the effluent from the equalization tank of an aging landfill, which then enters a reverse osmosis membrane system for further treatment, ultimately achieving compliant discharge. Through the coordinated design of the primary sedimentation tank 1, sand filter tank 2, pH adjustment tank 3, and effluent storage tank 4, the pretreatment process is optimized, overcoming the bottleneck in leachate treatment efficiency in aging landfills and achieving the goal of high-efficiency and low-consumption pretreatment.

[0067] The landfill leachate pretreatment system in this embodiment has a simple and reasonable structure with strong overall integration, achieving step-by-step purification of leachate: the primary sedimentation tank removes large suspended solids through sedimentation, reducing the load on subsequent treatment; the sand filter tank utilizes the interception, sedimentation, and adsorption effects of quartz sand to effectively remove suspended solids larger than 40 microns and some organic matter, providing high-quality feed water for the reverse osmosis system; the pH adjustment tank maintains the effluent pH at a stable 6-7 through automatic control, avoiding damage to the membrane system caused by water quality fluctuations. This ensures that the pretreated leachate meets the reverse osmosis feed water standards, significantly reduces membrane fouling, extends the service life of membrane modules, improves the system's shock resistance, ensures efficient operation of deep reverse osmosis treatment, and achieves stable and compliant discharge of leachate. Furthermore, the system adopts PLC linkage control and modular design, offering advantages such as high automation, convenient operation, and low maintenance costs. It improves the efficiency of front-end pretreatment of leachate from aging landfills, enhances the cost-effectiveness of the treatment system, has good applicability, and has broad application prospects.

[0068] The technical solution of this utility model has been described above with reference to the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the protection scope of this utility model is obviously not limited to these specific embodiments. Without departing from the principle of this utility model, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will all fall within the protection scope of this utility model.

[0069] The above description is merely a preferred embodiment of this utility model and is not intended to limit the scope of this utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, substitutions, or improvements made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A landfill leachate pretreatment system, characterized in that, include: A primary sedimentation tank, a sand filter tank, a pH adjustment tank, and an effluent storage tank are connected sequentially along the leachate flow direction. The effluent pipe of the primary sedimentation tank is equipped with a control console and an inlet pump. The electric valve of the control console is linked to the sand filter tank, and the inlet pump is connected to the inlet of the sand filter tank. The pH adjustment tank is connected to the inlet of the effluent storage tank through an overflow pipe. The primary sedimentation tank, sand filter tank, pH adjustment tank, and effluent storage tank are each connected to the dewatering supernatant tank through a drain pipe.

2. The landfill leachate pretreatment system according to claim 1, characterized in that, The inlet of the primary sedimentation tank is located at the bottom of the tank body, and the outlet is located in the middle of the tank body; the outlet pipe of the primary sedimentation tank is divided into two lines, one line is connected to the sand filter tank, and the other line is connected to the dewatering supernatant tank through a pipe; a sludge outlet is provided at the bottom of the primary sedimentation tank.

3. The landfill leachate pretreatment system according to claim 1, characterized in that, The inlet of the sand filter tank is located at the upper part of the tank body, and the outlet is located at the lower part of the tank body. The inside of the sand filter tank is filled with filter media for removing impurities and some organic matter from the leachate, and the filter media occupies a part of the volume of the sand filter tank body.

4. The landfill leachate pretreatment system according to claim 1, characterized in that, The pH adjusting tank is externally connected to a hydrochloric acid diaphragm pump; a stirrer is installed on the upper part of the pH adjusting tank, and a stirring device is installed on the bottom side of the tank body; the stirrer is driven and connected to the stirring device.

5. The landfill leachate pretreatment system according to claim 2, characterized in that, The inlet of the water storage tank is located at the top of the tank body, and the outlet is located at the bottom of the tank body; the top of the water storage tank body is provided with an overflow pipe, and the bottom of the tank body is provided with a drain valve, which is connected to the drain pipe.

6. The landfill leachate pretreatment system according to claim 2, characterized in that, The primary settling tank is equipped with a high level gauge and a low level gauge, which are respectively set at the high level and low level inside the primary settling tank.

7. The landfill leachate pretreatment system according to claim 2, characterized in that, The inlet and outlet pipes of the primary sedimentation tank are both equipped with flow meters for real-time monitoring of the inlet flow rate.

8. The landfill leachate pretreatment system according to claim 7, characterized in that, The primary sedimentation tank is connected to a bag filter, and the outlet of the bag filter is connected to the inlet of the primary sedimentation tank via a flow meter on the inlet pipe of the primary sedimentation tank.

9. The landfill leachate pretreatment system according to claim 2, characterized in that, A sand filter variable frequency water inlet pump is installed on one of the water outlet pipes from the primary sedimentation tank to the sand filter tank, and the sand filter variable frequency water inlet pump is connected to the sand filter tank.

10. The landfill leachate pretreatment system according to any one of claims 1-9, characterized in that, Also includes: The control system is electrically connected to the pumps, valves, pH probes, hydrochloric acid diaphragm pumps, and level gauges installed or connected to the primary sedimentation tank, sand filter tank, pH adjustment tank, effluent storage tank, and bag filter, respectively. The control system includes a PLC controller.

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