A system and process for treating concentrated water from leachate in a domestic waste landfill

Abstract

The present application relates to the field of wastewater treatment, and in particular to a system and process for treating concentrated leachate from a domestic waste landfill. The treatment system is arranged in sequence along the treatment order: a filter box with a built-in organic nanofiltration membrane for reducing the concentrated leachate; a first homogenizing reaction tank for performing a first pH adjustment and a first coagulation treatment on the reduced wastewater; a first solid-liquid separation device for performing solid-liquid separation on the mud-water mixture after the first coagulation treatment and extracting solid humic acid; a second homogenizing reaction tank for performing a second pH adjustment and a second coagulation treatment on the residual solution after the solid humic acid is extracted; and a second solid-liquid separation device for performing solid-liquid separation on the mud-water mixture after the second coagulation treatment. An organic nanofiltration membrane is arranged in the filter box to filter the concentrated leachate, thereby reducing the treatment volume of subsequent steps and saving energy consumption and reagent consumption.

Description

Technical Field

[0001] The present application relates to the field of wastewater treatment, and in particular to a system and process for treating concentrated water from leachate in a domestic waste landfill. Background Art

[0002] Leachate refers to a high-concentration organic wastewater formed by the moisture contained in the garbage itself in the landfill, rainwater, snow and other moisture entering the landfill, minus the saturated water holding capacity of the garbage and covering soil layers, and passing through the garbage layer and covering soil layer.

[0003] The concentrated water from the leachate of domestic waste landfills has a high organic content. Existing technology often uses high-pressure reverse osmosis to reprocess this high-concentration wastewater. However, the system has a low recovery rate, high energy consumption, and the membrane system is prone to fouling and clogging. Furthermore, the high organic content in the concentrated water from the leachate affects the subsequent use of the evaporator. The organic matter can affect the boiling point during evaporation and thus the processing capacity. Summary of the Invention

[0004] In order to solve the above problems, the present application provides a system and process for treating concentrated water from leachate in a domestic waste landfill.

[0005] The present application provides a system for treating concentrated water from a domestic waste landfill leachate, which adopts the following technical solutions:

[0006] A system for treating concentrated water from leachate from a domestic waste landfill is provided in the following order:

[0007] Filter box with built-in organic nanofiltration membrane for reducing the amount of leachate concentrate;

[0008] The first homogenization reaction tank is used to perform the first pH adjustment and first coagulation treatment on the reduced wastewater;

[0009] The first solid-liquid separation equipment is used to separate the mud-water mixture after the first coagulation treatment into solid and liquid and extract solid humic acid;

[0010] A second homogenizing reaction tank is used to perform a second pH adjustment and a second coagulation treatment on the remaining solution after the solid humic acid is extracted; and

[0011] The second solid-liquid separation equipment is used to separate the solid and liquid of the mud-water mixture after the second coagulation treatment.

[0012] Further preferably, the filter box includes:

[0013] A box body, wherein an inclined channel is formed in the box body, the organic nanofiltration membrane is fixedly disposed in the inclined channel, and the lower end of the inclined channel is connected to a water production space for receiving a solution passing through the organic nanofiltration membrane and a storage space for receiving a solution intercepted by the organic nanofiltration membrane;

[0014] A feed pipe connected to the upper starting end of the inclined channel;

[0015] a discharge pipe connected to the water production space for discharging the solution in the water production space;

[0016] a pressure valve, fixedly installed in the storage space and located on a side of the storage space away from the inclined channel and controlling the switch based on the pressure of the solution in the storage space;

[0017] an on-off valve fixedly installed in the material storage space and located at a position where the inclined channel communicates with the material storage space, and is switched on and off based on the switching of the pressure valve, wherein the pressure valve and the on-off valve have different switching modes; and

[0018] A discharge pipe is connected to the pressure valve.

[0019] Further preferably, the organic nanofiltration membrane is arranged along the inclined direction of the inclined channel, and the inclination angle of the organic nanofiltration membrane to the horizontal direction is less than 45°.

[0020] Further preferably, a plurality of supporting ribs for supporting the organic nanofiltration membrane are fixedly provided in the inclined channel.

[0021] Further preferably, the support ribs are wavy along the inclination direction of the inclined channel.

[0022] Further preferably, the first homogeneous reaction tank and the second homogeneous reaction tank both include:

[0023] A cell body is provided with a processing space, the cell body being connected with a feed connection pipe for receiving a solution to be treated and a discharge connection pipe for discharging a treated product;

[0024] a first regulator metering pump, configured to add a pH regulator to the processing space, wherein the start and stop of the first regulator metering pump is controlled based on the pH value of the solution in the processing space;

[0025] a coagulant metering pump, for adding coagulant into the treatment space;

[0026] a stirring member, for stirring the solution in the processing space; and

[0027] The driving source provides a rotational driving force for the stirring member and can drive the stirring member to rise and fall.

[0028] It is further preferred that the discharge connecting pipe in the first homogenizing reaction tank is connected to a second regulator metering pump for adding a pH regulator into the pipe.

[0029] Further preferably, a movable disk is provided in the processing space so as to move up and down, a rotating disk is rotatably mounted on the movable disk, a lifting shaft is fixedly connected to the rotating disk, one end of the lifting shaft away from the rotating disk is dynamically connected to the driving source, and the driving source can drive the lifting shaft to move up and down to achieve the lifting of the rotating disk and the movable disk;

[0030] A first through hole is provided in the rotating disk and passes through it from top to bottom, and a second through hole is provided in the moving disk and passes through it from top to bottom.

[0031] Further preferably, a detector for monitoring the transparency of the solution in the processing space is fixedly connected to the lower end of the movable plate, and the detector is electrically connected to the driving source.

[0032] The present application also provides a treatment process based on the above-mentioned landfill leachate concentrate treatment system, comprising the following process steps:

[0033] S1: The concentrated leachate to be treated enters the filter box for filtration to obtain a solution filtered by an organic nanofiltration membrane and a solution intercepted by an organic nanofiltration membrane;

[0034] If the solution filtered by the organic nanofiltration membrane meets the discharge standard, it will be discharged directly. If it does not meet the standard, it will be returned for re-filtration.

[0035] The solution intercepted by the organic nanofiltration membrane enters the first homogenization reaction tank;

[0036] S2: pH adjustment and coagulation treatment are performed in the first homogenization reaction tank, and the mixture is stirred thoroughly. After standing for 2-3 hours, the bottom mud-water mixture and the upper solution are obtained;

[0037] wherein the pH in the first homogenizing reaction tank is adjusted to 1.5-2.0;

[0038] The coagulant dosage is 1000-3000ppm and is added continuously and evenly;

[0039] S3: The bottom mud-water mixture obtained in step S2 is sent to the first solid-liquid separation device, and a pH regulator is added to the mud-water mixture during the transportation process to adjust the pH to 4.0-5.0, and the upper layer solution is returned for re-filtration;

[0040] S4: The first solid-liquid separation equipment performs solid-liquid separation on the mud-water mixture and obtains the separated solid humic acid and liquid solution;

[0041] S5: The liquid solution obtained in step S4 is sent to a second homogenization reaction tank, where the pH is adjusted and coagulation is performed, the mixture is stirred evenly, and the bottom mud-water mixture and the upper solution are obtained after standing for 2-3 hours;

[0042] wherein the pH in the second homogenizing reaction tank is adjusted to 8.0-8.5;

[0043] The coagulant dosage is 500-2000ppm and is added continuously and evenly;

[0044] S6: returning the upper layer solution obtained in step S5 for re-filtration, sending the bottom mud-water mixture obtained in step S5 to a second solid-liquid separation device for solid-liquid separation, and obtaining the separated solid sludge and liquid solution;

[0045] S7: The solid sludge obtained in step S6 is transported out for treatment, and the liquid solution obtained in step S6 is returned for re-filtration treatment.

[0046] In summary, this application has at least the following beneficial effects:

[0047] 1. An organic nanofiltration membrane is installed in the filter box to filter the concentrated water of the landfill leachate, reducing the processing volume of subsequent steps and saving energy and chemical consumption.

[0048] 2. The humic acid products produced in the treatment process can be used as fertilizers to improve the recycling rate of wastewater. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 This is a system block diagram of a concentrated water treatment system for leachate from a domestic waste landfill;

[0050] Figure 2 It is a vertical cross-sectional diagram of the filter box;

[0051] Figure 3 1 is a vertical cross-sectional schematic diagram of the first homogeneous reaction tank / the second homogeneous reaction tank;

[0052] Figure 4 The present invention is a process flow chart of a concentrated water treatment process for leachate from a domestic waste landfill.

[0053] Description of reference numerals:

[0054] 1. Box body; 2. Feed pipe; 3. Inclined channel; 4. Support ribs; 5. Organic nanofiltration membrane; 6. Switch valve; 7. Storage space; 8. Pressure valve; 9. Water production space; 10. Discharge pipe; 11. Discharge pipe; 12. Support frame; 13. Drive source; 14. Feed connecting pipe; 15. First regulator metering pump; 16. Discharge connecting pipe; 17. Coagulant metering pump; 18. Stirring element; 19. Lifting shaft; 20. Tank body; 21. Detector; 22. Processing space; 23. First through hole; 24. Rotating disk; 25. Moving disk; 26. Second through hole. DETAILED DESCRIPTION

[0055] The following is a detailed description of the specific embodiments of the present invention. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present invention and are not intended to limit the present invention.

[0056] In the present invention, unless otherwise specified, directional terms such as "upper" and "lower" generally refer to directions in the assembled state. "Inside" and "outside" refer to inside and outside relative to the outline of each component itself.

[0057] The present invention discloses a system for treating concentrated water from leachate in a domestic waste landfill. Figure 1 As shown, a filter box, a first homogenizing reaction tank, a first solid-liquid separation device, a second homogenizing reaction tank, and a second solid-liquid separation device are provided in the order of treatment. The first solid-liquid separation device and the second solid-liquid separation device can be conventional gravity (sedimentation) separation devices, centrifugal separation devices, filter screen separation devices, and the like.

[0058] An organic nanofiltration membrane 5 is provided in the filter box for filtering and reducing the amount of leachate concentrate. Due to the selective permeability of the organic nanofiltration membrane 5, water molecules and monovalent ions in the wastewater can pass through the organic nanofiltration membrane 5, while the remaining organic matter and divalent ions in the wastewater are intercepted by the organic nanofiltration membrane 5. In the actual filtration process, the side that passes through the organic nanofiltration membrane 5 is called the water production side, and the other side is called the concentrate side. Most of the water molecules and monovalent ions in the wastewater pass through the organic nanofiltration membrane 5 and are located on the water production side, while organic matter, divalent ions and a small portion of water molecules are enriched and concentrated on the concentrate side, thereby reducing the amount of wastewater on the concentrate side, reducing the processing pressure of subsequent treatment processes, and thus saving energy consumption and reagent usage.

[0059] The first homogenizing reaction tank performs the first pH adjustment and first coagulation treatment on the reduced wastewater. The first solid-liquid separation equipment performs solid-liquid separation and extracts solid humic acid from the mud-water mixture after the first coagulation treatment. The second homogenizing reaction tank performs the second pH adjustment and second coagulation treatment on the remaining solution after the solid humic acid extraction. The second solid-liquid separation equipment performs solid-liquid separation on the mud-water mixture after the second coagulation treatment.

[0060] Specifically, in conjunction with Figure 2 The filter box includes a box body 1 , a feed pipe 2 , a discharge pipe 10 , a pressure valve 8 , a switch valve 6 and a discharge pipe 11 .

[0061] The housing 1 includes an inclined channel 3, in which an organic nanofiltration membrane 5 is fixedly mounted. The lower end of the inclined channel 3 communicates with a water production space 9 for receiving solution passing through the organic nanofiltration membrane 5, and a storage space 7 for receiving solution intercepted by the organic nanofiltration membrane 5. In this embodiment, the configuration of the inclined channel 3 allows the wastewater to flow along the inclined channel 3 under the action of gravity and be filtered by the organic nanofiltration membrane 5, without requiring additional driving force for the liquid flow.

[0062] The feed pipe 2 is connected to the upper starting end of the inclined channel 3 , and the wastewater to be treated enters the inclined channel 3 through the feed pipe 2 .

[0063] The discharge pipe 10 is connected to the water production space 9 and is used to discharge the solution in the water production space 9. It should be noted that wastewater discharge generally has emission standards, so a wastewater detector (not shown) is required in the water production space 9 to detect the solution in the water production space 9. If the solution in the water production space 9 meets the emission standards, it can be discharged through the discharge pipe 10. If the solution in the water production space 9 does not meet the emission standards, the discharge pipe 10 will discharge the solution in the water production space 9 to other wastewater treatment systems for further treatment, or discharge the solution in the water production space 9 into the feed pipe 2 and return it to the filter box for treatment.

[0064] In summary, the end of discharge pipe 10 away from water production space 9 can be connected to a wastewater discharge system that controls the discharge destination of wastewater based on the test results of the solution in water production space 9. In this embodiment, discharge pipe 10 and feed pipe 2 are connected. If the solution in water production space 9 does not meet the discharge standards, the solution in water production space 9 is returned to the filter box through discharge pipe 10 and feed pipe 2 for treatment.

[0065] Pressure valve 8 is fixedly installed in the discharge space, located on the side of storage space 7 away from inclined channel 3. Its opening and closing are controlled by the pressure of the solution in storage space 7. On-off valve 6 is fixedly installed in storage space 7, located at the connection point between inclined channel 3 and storage space 7. Its opening and closing are controlled by pressure valve 8. Pressure valve 8 and on-off valve 6 have different opening and closing modes. A discharge pipe 11 is connected to pressure valve 8.

[0066] Because on-off valve 6 and pressure valve 8 have different opening and closing functions and on-off valve 6 is installed at the connection point between storage space 7 and inclined channel 3, storage space 7 and inclined channel 3 can only be connected after on-off valve 6 is opened. Therefore, when on-off valve 6 is open and pressure valve 8 is closed, wastewater intercepted by organic nanofiltration membrane 5 enters storage space 7 and is stored until the pressure exerted by the solution in storage space 7 on pressure valve 8 reaches the pressure valve 8 threshold. In other words, when the solution in storage space 7 reaches a certain amount, pressure valve 8 opens, on-off valve 6 closes, and the solution in storage space 7 is discharged from the filter box through discharge pipe 11.

[0067] Without considering valve measurement accuracy, the coordinated arrangement of pressure valve 8 and on-off valve 6 can control the amount of solution discharged from discharge pipe 11 to remain consistent each time, facilitating throughput control in subsequent processing steps. Furthermore, filtration processing typically takes a long time. By the time the amount of solution in storage space 7 reaches the discharge capacity, the subsequent processing equipment in the filter box has already completed processing the previous batch of solution. Therefore, the control factors for on-off valve 6 and pressure valve 8 only need to be based on the pressure of the solution in storage space 7.

[0068] Of course, in some special cases, the subsequent processing equipment and processes in the filter box may take longer. Specifically, when the solution volume in storage space 7 has reached the discharge capacity (the solution pressure has reached the threshold set by pressure valve 8), the subsequent processing equipment in the filter box has not yet completed processing the previous round of solution. At this time, the opening and closing of on-off valve 6 and pressure valve 8 must be controlled based on whether the subsequent processing equipment in the filter box is in the processing state.

[0069] In some embodiments, the organic nanofiltration membrane 5 is arranged along the inclined direction of the inclined channel 3, and the inclination angle of the organic nanofiltration membrane 5 to the horizontal direction is less than 45 degrees to avoid the wastewater to be treated flowing too fast and affecting the filtration effect.

[0070] In some embodiments, a plurality of support ribs 4 for supporting the organic nanofiltration membrane 5 are fixedly provided in the inclined channel 3. The provision of the support ribs 4 is conducive to improving the strength of the organic nanofiltration membrane 5, and the use of ribs can also avoid occupying too much area of ​​the organic nanofiltration membrane 5 and affecting the filtration effect.

[0071] In some embodiments, the support ribs 4 are wavy along the inclined direction of the inclined channel 3, causing the organic nanofiltration membrane 5 to also wavy along the inclined direction of the inclined channel 3. This further reduces the flow rate of the wastewater to be treated, prolongs the contact time between the wastewater and the organic nanofiltration membrane 5, and improves the filtration effect. In this embodiment, the organic nanofiltration membrane 5 filters 75% to 80% of the wastewater to be treated. That is, the amount of water produced by the organic nanofiltration membrane 5 accounts for 75% to 80% of the total treatment volume, and the amount of wastewater intercepted by the organic nanofiltration membrane 5 accounts for 20% to 25% of the total treatment volume.

[0072] In a further embodiment, the Figure 3 As shown, the first homogenizing reaction tank and the second homogenizing reaction tank both include a tank body 20 , a first regulating metering pump, a coagulant metering pump 17 , a stirring element 18 and a driving source 13 .

[0073] Specifically, a processing space 22 is defined within the tank body 20. Connected to the tank body 20 are a feed connection pipe 14 for receiving the solution to be treated and a discharge connection pipe 16 for discharging the treated product. Depending on the treatment sequence, the feed connection pipe 14 of the first homogenizing reaction tank communicates with the discharge pipe in the filter tank, while the feed connection pipe 14 of the second homogenizing reaction tank communicates with the first solid-liquid separation device.

[0074] The first regulator metering pump 15 is used to add a pH regulator to the processing space 22. The pH regulator can be an acidic substance such as hydrochloric acid or sulfuric acid. The start and stop of the first regulator metering pump 15 is controlled based on the pH value of the solution in the processing space 22. Specifically, a pH sensor (not shown) is provided in the processing space 22, and the start and stop of the first regulator metering pump 15 is controlled based on the sensor's detection results.

[0075] The coagulant metering pump 17 is used to add coagulant into the processing space 22. The coagulant is generally ferric chloride, polyferric PFS or other coagulants. The addition process of the coagulant metering pump 17 is a continuous and uniform process to ensure uniform coagulation effect.

[0076] The stirring element 18 is used to stir the solution in the treatment space 22 to improve pH adjustment and coagulation speed, thereby accelerating treatment efficiency.

[0077] The drive source 13 provides rotational driving force for the agitator 18 and can also drive the agitator 18 up and down. Specifically, the drive source 13 is an integrated drive system for rotational drive and elevation drive. It not only provides rotational driving force for the agitator 18, but also drives the agitator 18 up and down to facilitate removal from the processing space 22 for cleaning and maintenance. In this embodiment, a support frame 12 is provided outside the tank body 20 for hoisting the drive source 13, so that the drive source 13 is located at the top of the tank body 20 to facilitate the driving and raising and lowering of the agitator 18.

[0078] In some embodiments, a movable disk 25 is provided in the processing space 22 so as to move up and down. A rotating disk 24 is rotatably mounted on the movable disk 25. A lifting shaft 19 is fixedly connected to the rotating disk 24. The lifting shaft 19 is poweredly connected to the driving source 13 at one end away from the rotating disk 24, and the driving source 13 can drive the lifting shaft 19 to move up and down to achieve the lifting of the rotating disk 24 and the movable disk 25. A first through hole 23 is provided in the rotating disk 24 and runs through it from top to bottom, and a second through hole 26 is provided in the movable disk 25 and runs through it from top to bottom. When the rotating disk 24 is driven by the driving source 13 to rotate relative to the movable disk 25, so that the first through hole 23 and the second through hole 26 are connected, the stirring member 18 can move downward under the drive of the driving source 13 and pass through the first through hole 23 and the second through hole 26 and be located in the processing space 22 to stir the solution.

[0079] In some embodiments, a detector 21 for monitoring the transparency of the solution in the processing space 22 is fixedly connected to the lower end of the movable disk 25. The driving source 13 drives the rotating disk 24 and the movable disk 25 to move up and down, and detects the transparency of the solution in the processing space 22 at different water levels through the detector 21. When the detector 21 detects the water level at which the transparency suddenly changes, the driving source 13 stops driving the rotating disk 24 and the movable disk 25 to move up and down. At this time, the position of the rotating disk 24 and the movable disk 25 is the boundary position between the upper solution and the bottom mud-water mixture in the processing space 22. At this time, the driving source 13 drives the rotating disk 24 to rotate, so that the first through hole 23 and the second through hole 26 are staggered, thereby separating the upper solution and the bottom mud-water mixture from each other. At this time, the discharge connecting pipe 16 can discharge the mud-water mixture to the solid-liquid separation equipment. Specifically, the discharge connecting pipe 16 in the first homogeneous reaction tank discharges the mud-water mixture in the first homogeneous reaction tank to the first solid-liquid separation equipment, and the discharge connecting pipe 16 in the second homogeneous reaction tank discharges the mud-water mixture in the second homogeneous reaction tank to the second solid-liquid separation equipment.

[0080] After the mud-water mixture in the treatment space 22 is discharged, the driving source 13 drives the rotating disk 24 to rotate so that the first through hole 23 and the second through hole 26 are connected, so that the upper layer solution in the treatment space 22 can be discharged through the discharge connecting pipe 16. The discharge destination of the upper layer solution can be direct discharge, or returned to the feed pipe 2 of the filter box, or discharged into other wastewater treatment systems. In this embodiment, the upper layer solution needs to be returned to the feed pipe 2 of the filter box and re-filtered. Therefore, the end of the discharge connecting pipe 16 needs to be provided with a discharge system that switches the discharge path based on the type of discharge.

[0081] In a further embodiment, a second regulator metering pump (not shown) is connected to the discharge connection pipe 16 in the first homogenizing reaction tank for adding a pH regulator to the pipe. Specifically, the second regulator metering pump is provided on the discharge connection pipe 16 to add a regulator such as caustic soda flakes or lime solution to the pipe. This not only facilitates the extraction of humic acid products from the solution, but also brings the solution pH closer to neutral, reducing corrosion to equipment and piping.

[0082] The steps for using the concentrated water treatment system for leachate from a domestic waste landfill of the present invention are as follows:

[0083] First, the wastewater to be treated enters the filter box through the feed pipe 2, and is filtered and treated by the organic nanofiltration membrane 5. The solution passing through the organic nanofiltration membrane 5 enters the water production space 9 and is discharged accordingly after detection; the solution intercepted by the organic nanofiltration membrane 5 enters the storage space 7.

[0084] Secondly, when the solution in the storage space 7 reaches a certain amount, the pressure valve 8 opens and discharges the solution into the first homogenization reaction tank for pH adjustment, coagulation and static sedimentation;

[0085] Next, the driving source 13 drives the rotating disk 24 and the moving disk 25 at the first homogeneous reaction tank to descend, and separates the upper layer solution and the bottom layer mud-water mixture in the processing space 22 of the first homogeneous reaction tank, and discharges the mud-water mixture into the first solid-liquid separation device through the discharge connecting pipe 16. During the process of discharging the mud-water mixture from the first homogeneous reaction tank to the first solid-liquid separation device, the pH of the solution is adjusted. After the mud-water mixture is completely discharged from the first homogeneous reaction tank, the driving source 13 drives the rotating disk 24 at the first homogeneous reaction tank to rotate so that the first through hole 23 and the second through hole 26 are connected, and the discharge connecting pipe 16 discharges the upper layer solution.

[0086] Then, the first solid-liquid separation equipment performs solid-liquid separation on the mud-water mixture to obtain solid humic acid and liquid solution. The solid humic acid can be used as fertilizer, and the liquid solution is discharged into the second homogenization reaction tank.

[0087] Then, pH adjustment, coagulation, and static sedimentation are performed in the second homogeneous reaction tank. The driving source 13 drives the rotating disk 24 and the movable disk 25 at the second homogeneous reaction tank to descend, and separates the upper layer solution and the bottom mud-water mixture in the processing space 22 of the second homogeneous reaction tank. The mud-water mixture is discharged into the second solid-liquid separation device through the discharge connecting pipe 16. After the mud-water mixture is completely discharged from the second homogeneous reaction tank, the driving source 13 drives the rotating disk 24 at the second homogeneous reaction tank to rotate so that the first through hole 23 and the second through hole 26 are connected, and the discharge connecting pipe 16 discharges the upper layer solution.

[0088] Finally, the second solid-liquid separation equipment separates the mud-water mixture into solid and liquid, obtaining solid sludge and liquid solution. The solid sludge is transported out for treatment, and the liquid solution is directly discharged or returned to the feed pipe 2 of the filter box or other wastewater treatment systems.

[0089] The present invention also provides a treatment process based on the above-mentioned domestic waste landfill leachate concentrated water treatment system, combined with the attached Figure 4 , including the following process steps:

[0090] S1: The concentrated leachate to be treated enters the filter box for filtration to obtain a solution filtered by the organic nanofiltration membrane 5 and a solution intercepted by the organic nanofiltration membrane 5;

[0091] If the solution filtered by the organic nanofiltration membrane 5 meets the discharge standard, it will be discharged directly. If it does not meet the standard, it will be returned for re-filtration.

[0092] The solution intercepted by the organic nanofiltration membrane 5 enters the first homogenization reaction tank;

[0093] S2: pH adjustment and coagulation treatment are performed in the first homogenization reaction tank, and the mixture is stirred thoroughly. After standing for 2-3 hours, the bottom mud-water mixture and the upper solution are obtained;

[0094] wherein the pH in the first homogenizing reaction tank is adjusted to 1.5-2.0;

[0095] The coagulant dosage is 1000-3000ppm and is added continuously and evenly;

[0096] S3: The bottom mud-water mixture obtained in step S2 is sent to the first solid-liquid separation device, and a pH regulator is added to the mud-water mixture during the transportation process to adjust the pH to 4.0-5.0, and the upper layer solution is returned for re-filtration;

[0097] S4: The first solid-liquid separation equipment performs solid-liquid separation on the mud-water mixture and obtains the separated solid humic acid and liquid solution;

[0098] S5: The liquid solution obtained in step S4 is sent to a second homogenization reaction tank, where the pH is adjusted and coagulation is performed, the mixture is stirred evenly, and the bottom mud-water mixture and the upper solution are obtained after standing for 2-3 hours;

[0099] wherein the pH in the second homogenizing reaction tank is adjusted to 8.0-8.5;

[0100] The coagulant dosage is 500-2000ppm and is added continuously and evenly;

[0101] S6: returning the upper layer solution obtained in step S5 for re-filtration, sending the bottom mud-water mixture obtained in step S5 to a second solid-liquid separation device for solid-liquid separation, and obtaining the separated solid sludge and liquid solution;

[0102] S7: The solid sludge obtained in step S6 is transported out for treatment, and the liquid solution obtained in step S6 is returned for re-filtration treatment.

[0103] The preferred embodiments of the present invention are described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the scope of protection of the present invention.

[0104] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any appropriate manner without contradiction. To avoid unnecessary repetition, the present invention will not further describe various possible combinations.

[0105] In addition, the various embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the present invention, they should also be regarded as the contents disclosed by the present invention.

Claims

1. A system for treating concentrated water from a domestic waste landfill leachate, characterized in that: Set in the processing order: A filter box with a built-in organic nanofiltration membrane (5) for reducing the amount of concentrated leachate; The first homogenization reaction tank is used to perform the first pH adjustment and first coagulation treatment on the reduced wastewater; The first solid-liquid separation equipment is used to separate the mud-water mixture after the first coagulation treatment into solid and liquid and extract solid humic acid; The second homogenization reaction tank is used to perform a second pH adjustment and a second coagulation treatment on the remaining solution after the solid humic acid is extracted; as well as The second solid-liquid separation equipment is used to separate the solid and liquid of the mud-water mixture after the second coagulation treatment; The first homogeneous reaction tank and the second homogeneous reaction tank both include: A cell body (20) is provided with a processing space (22), and the cell body (20) is connected to a feed connection pipe (14) for receiving a solution to be treated and a discharge connection pipe (16) for discharging a treated product; a stirring member (18) for stirring the solution in the processing space (22); and A driving source (13) provides a rotational driving force for the stirring member (18) and is capable of driving the stirring member (18) to move upward and downward; A movable disk (25) is provided in the processing space (22) so as to move up and down, a rotating disk (24) is rotatably mounted on the movable disk (25), a lifting shaft (19) is fixedly connected to the rotating disk (24), and one end of the lifting shaft (19) away from the rotating disk (24) is dynamically connected to the driving source (13), and the driving source (13) can drive the lifting shaft (19) to move up and down to realize the lifting and lowering of the rotating disk (24) and the movable disk (25); A first through hole (23) is provided in the rotating disk (24) and extends vertically therethrough, and a second through hole (26) is provided in the moving disk (25) and extends vertically therethrough; The driving source (13) drives the rotating disk (24) to rotate relative to the moving disk (25), so that the first through hole (23) and the second through hole (26) are connected. The stirring member (18) can move downward under the driving of the driving source (13) and pass through the first through hole (23) and the second through hole (26) and be located in the processing space (22) to stir the solution.

2. The domestic waste landfill leachate concentrated water treatment system according to claim 1, characterized in that: The filter box comprises: A box body (1) is provided with an inclined channel (3), the organic nanofiltration membrane (5) is fixedly arranged in the inclined channel (3), and the lower end of the inclined channel (3) is connected to a water production space (9) for receiving a solution passing through the organic nanofiltration membrane (5) and a storage space (7) for receiving a solution intercepted by the organic nanofiltration membrane (5); A feed pipe (2) connected to the upper starting end of the inclined channel (3); a discharge pipe (10), connected to the water production space (9) and used for discharging the solution in the water production space (9); A pressure valve (8) is fixedly installed in the storage space (7) and is located on a side of the storage space (7) away from the inclined channel (3) and controls the switch based on the pressure of the solution in the storage space (7); an on-off valve (6) fixedly mounted in the material storage space (7) and located at a position where the inclined channel (3) and the material storage space (7) are connected and is switched based on the on-off of the pressure valve (8), wherein the on-off operation of the pressure valve (8) is different from that of the on-off valve (6); and The discharge pipe (11) is connected to the pressure valve (8).

3. The domestic waste landfill leachate concentrated water treatment system according to claim 2, characterized in that: The organic nanofiltration membrane (5) is arranged along the inclined direction of the inclined channel (3), and the inclination angle of the organic nanofiltration membrane (5) to the horizontal direction is less than 45°.

4. The system for treating concentrated water from a domestic waste landfill leachate according to claim 2, characterized in that: A plurality of support ribs (4) for supporting the organic nanofiltration membrane (5) are fixedly provided in the inclined channel (3).

5. The domestic waste landfill leachate concentrated water treatment system according to claim 4, characterized in that: The supporting ribs (4) are wavy along the inclination direction of the inclined channel (3).

6. The system for treating concentrated water from leachate from a domestic waste landfill according to any one of claims 1 to 5, characterized in that: The first homogeneous reaction tank and the second homogeneous reaction tank both further include: a first regulator metering pump (15) for adding a pH regulator into the processing space (22), wherein the start and stop of the first regulator metering pump (15) is controlled based on the pH value of the solution in the processing space (22); A coagulant metering pump (17) is used to add coagulant into the processing space (22).

7. The concentrated water treatment system for leachate from a domestic waste landfill according to claim 6, characterized in that: The discharge connecting pipe (16) in the first homogenizing reaction tank is connected to a second regulator metering pump for adding a pH regulator into the pipe.

8. The domestic waste landfill leachate concentrated water treatment system according to claim 1, characterized in that: A detector (21) for monitoring the transparency of the solution in the processing space (22) is fixedly connected to the lower end of the movable disk (25), and the detector (21) is electrically connected to the driving source (13).

9. A treatment process based on the concentrated water treatment system for leachate from a domestic waste landfill according to any one of claims 1 to 8, characterized in that: The process steps include: S1: The concentrated leachate to be treated enters the filter box for filtration to obtain a solution filtered by the organic nanofiltration membrane (5) and a solution intercepted by the organic nanofiltration membrane (5); If the solution filtered by the organic nanofiltration membrane (5) meets the discharge standard, it will be discharged directly; if it does not meet the standard, it will be returned for re-filtration; The solution intercepted by the organic nanofiltration membrane (5) enters the first homogenization reaction tank; S2: pH adjustment and coagulation treatment are performed in the first homogenization reaction tank, and the mixture is stirred thoroughly. After standing for 2-3 hours, the bottom mud-water mixture and the upper solution are obtained; wherein the pH in the first homogenizing reaction tank is adjusted to 1.5-2.0; The coagulant dosage is 1000-3000ppm and is added continuously and evenly; S3: The bottom mud-water mixture obtained in step S2 is sent to the first solid-liquid separation device, and a pH regulator is added to the mud-water mixture during the transportation process to adjust the pH to 4.0-5.0, and the upper layer solution is returned for re-filtration; S4: The first solid-liquid separation equipment performs solid-liquid separation on the mud-water mixture and obtains the separated solid humic acid and liquid solution; S5: The liquid solution obtained in step S4 is sent to a second homogenization reaction tank, where the pH is adjusted and coagulation is performed, the mixture is stirred evenly, and the bottom mud-water mixture and the upper solution are obtained after standing for 2-3 hours; wherein the pH in the second homogenizing reaction tank is adjusted to 8.0-8.5; The coagulant dosage is 500-2000ppm and is added continuously and evenly; S6: returning the upper layer solution obtained in step S5 for re-filtration, sending the bottom mud-water mixture obtained in step S5 to a second solid-liquid separation device for solid-liquid separation, and obtaining the separated solid sludge and liquid solution; S7: The solid sludge obtained in step S6 is transported out for treatment, and the liquid solution obtained in step S6 is returned for re-filtration treatment.

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