Ultrasonic anti-clogging permeable reactive barrier

Abstract

The ultrasonic anti-clogging permeable reactive barrier comprises a wall body, an ultrasonic vibration plate and an ultrasonic generator, the interior of the wall body is hollow, the top of the wall body is open, the interior of the wall body is divided into a filler bin and an ultrasonic vibration plate bin through a partition plate, the filler bin is filled with PRB reaction filler, and the interior of the ultrasonic vibration plate bin is filled with the PRB reaction filler. The ultrasonic vibration plate is installed in the ultrasonic vibration plate bin and electrically connected with the ultrasonic generator through a cable. The upstream face of the wall body, the downstream face of the filler bin and the partition plate are all provided with water through holes. When the device works, extremely strong shock waves and microjets are generated through ultrasonic waves, a passivation layer formed on the surface of the PRB reaction filler in the degradation process is removed through the vibration and stirring effects of the ultrasonic waves, the problems that the surface of the PRB reaction filler is passivated and a system is blocked in the operation process of the permeable reactive barrier are solved, and therefore the repairing efficiency of pollutants in underground water is improved.

Description

Technical Field

[0001] The utility model belongs to the technical field of sewage treatment, and particularly relates to an ultrasonic anti-clogging permeable reaction wall. Background Art

[0002] Permeable reactive wall (PRB) technology, as an in-situ remediation technology for contaminated groundwater, avoids the problems of traditional extraction and treatment, such as high consumption, high cost, and the need for regular maintenance and monitoring. It is an in-situ passive system that requires no external power, does not occupy ground space, is low-cost, has replaceable remediation fillers, is universal in removing pollutants, requires almost no operating costs after installation, and has little impact on the ecological environment.

[0003] The key to PRB technology lies in the efficient function of the PRB reaction medium (PRB reaction filler) within the reaction wall. Among various PRB reaction media, zero-valent iron (ZVI) is widely used in the remediation of environmental pollutants due to its small particle size, large specific surface area, and high reactivity. However, due to its easy passivation and agglomeration, the accumulation of adsorbents on the PRB reaction filler, the accumulation of sediment, and the excessive growth or necrosis of microorganisms can lead to blockage of the PRB system, thereby affecting the remediation efficiency of groundwater pollutants. Utility Model Content

[0004] In view of this, the purpose of the present invention is to provide an ultrasonic anti-clogging permeable reaction wall to solve the problem of surface passivation of PRB reaction filler and system blockage during the operation of the permeable reaction wall, thereby improving the remediation efficiency of pollutants in groundwater.

[0005] The utility model solves the above problems through the following technical means:

[0006] An ultrasonic anti-clogging permeable reactive wall comprises a wall body, an ultrasonic vibration plate and an ultrasonic generator. The interior of the wall body is hollow and open at the top. The wall body is divided into a filling bin and an ultrasonic vibration plate bin by a partition. The filling bin is filled with PRB reactive filler. The ultrasonic vibration plate is installed in the ultrasonic vibration plate bin and is electrically connected to the ultrasonic generator via a cable. Water holes are provided on the water-facing surface of the wall body, the water-repelling surface of the filling bin and the partition.

[0007] In the process of implementing the above scheme, the material of the partition is stainless steel, and the back surface of the ultrasonic vibration plate bin is not provided with a water hole. Most of the groundwater enters the packing bin through the water hole on the water-facing surface of the wall. The pollutants are removed from the groundwater through the action of the pollutants on the PRB reaction packing (precipitation, adsorption, oxidation-reduction, fixation, and biodegradation). During the operation of the permeable reaction wall, the ultrasonic vibration plate is turned on regularly or irregularly according to the operation status of the permeable reaction wall to remove the passivated surface of the PRB reaction packing and restore its activity. At the same time, the sediment accumulated on the PRB reaction packing is peeled off, thereby improving the permeability of the packing and preventing the PRB system from being blocked.

[0008] A small amount of groundwater enters the ultrasonic vibrating plate chamber through water holes on the water-facing surface of the wall, then flows through water holes in the partition to the packing chamber, where it comes into contact with the PRB reactive filler. A suitable width is reserved where the backside of the packing chamber meets the ultrasonic vibrating plate chamber, extending the flow path of the groundwater entering the packing chamber through the PRB reactive filler, thereby ensuring effective pollutant removal. Groundwater entering the ultrasonic vibrating plate chamber enhances the propagation and diffusion of ultrasound waves while reducing energy loss.

[0009] Furthermore, a vertically extending slot is provided on the water-facing surface of the wall, and a water baffle or a filter screen is detachably mounted in the slot.

[0010] In the process of implementing the above solution, the slot can be set on the outside of the water-facing surface or on the inside of the water-facing surface, preferably on the inside of the water-facing surface; when the system is running, a filter screen inserted into the slot can initially filter out large particles of impurities in the groundwater, preventing external impurities from entering the PRB reaction packing and causing clogging of the PRB system. When the packing needs to be replaced or the ultrasonic vibration plate needs to be repaired, a water retaining plate is inserted into the slot to intercept the groundwater, making it easier to operate and reducing the amount of groundwater flowing downstream without being purified. After the packing is replaced or the ultrasonic vibration plate is repaired, the water retaining plate is removed and replaced with a filter screen, and the PRB reaction system can continue to operate.

[0011] Furthermore, a monitoring well is provided at the center of the filling bin, and a monitoring instrument is installed in the monitoring well.

[0012] In implementing the above solution, the size of the monitoring well should be sufficient to accommodate the monitoring equipment; smaller wells are generally used, preferably wells with a diameter of 2.5 cm or 5 cm, to minimize the damage caused by the monitoring wells to the flow field inside and around the PRB; the monitoring instruments are used to monitor the groundwater flow and water level inside each filling silo, and to promptly detect the reduction of porosity and deterioration of permeability due to barrier blockage.

[0013] Furthermore, a lifting ring is provided on the top of the ultrasonic vibration plate; the ultrasonic vibration plate can be lifted out of the ultrasonic vibration plate bin for inspection and maintenance.

[0014] Furthermore, the ultrasonic vibration plate includes an ultrasonic vibration plate housing and ultrasonic transducers staggeredly arranged on two opposite side walls of the ultrasonic vibration plate housing, and the ultrasonic transducers are electrically connected to the ultrasonic generator via a cable.

[0015] In the process of implementing the above solution, the material of the ultrasonic vibration plate shell is stainless steel, and the ultrasonic transducer in the ultrasonic vibration plate can be started and stopped in a graded manner through graded wiring. When the PRB reaction filler is locally blocked, only the ultrasonic vibration plate in the blocked area can be turned on to reduce the system operation energy consumption.

[0016] Beneficial effects of the utility model:

[0017] 1. The utility model discloses a permeable reaction wall for groundwater remediation. By arranging an ultrasonic vibration plate in the reaction chamber, when the PRB reaction filler is passivated on the surface or sediment accumulates, causing the PRB system processing efficiency to decrease or even become clogged, the ultrasonic vibration plate is turned on. The ultrasonic wave generates extremely strong shock waves and microjets, which remove the passivation layer formed on the surface of the PRB reaction filler during the degradation process through its vibration and stirring action, thereby strengthening the reduction degradation reaction on the interface and improving the removal rate. At the same time, due to its large specific surface area and strong adsorption capacity, the PRB reaction filler can adsorb microbubbles generated by ultrasonic cavitation on its surface, further strengthening the cavitation effect of the ultrasonic wave, effectively inhibiting the reproduction of microorganisms, peeling off the sediment accumulated on the PRB reaction filler, and expanding the gaps between the filler particles, thereby improving the permeability of the PRB reaction filler and ensuring the efficient operation of the PRB system.

[0018] 2. Furthermore, by setting up monitoring wells, the changes in groundwater flow can be monitored in real time, and the blockage location and degree of the PRB reaction filler can be confirmed so that the ultrasonic vibration plate can be opened in time. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0020] Figure 1 This is a schematic structural diagram of the ultrasonic anti-clogging permeable reaction wall of the utility model;

[0021] Figure 2 This is a cross-sectional view of the ultrasonic anti-clogging permeable reaction wall of the utility model;

[0022] Figure 3 Schematic diagram of the structure of the water retaining plate;

[0023] Figure 4 Schematic diagram of the filter structure.

[0024] Among them, 1: wall, 2: filling bin, 3: ultrasonic vibration plate bin, 4: slot, 5: monitoring well, 6: water hole, 7: lifting ring, 8: ultrasonic vibration plate, 9: ultrasonic generator, 10: cable, 11: PRB reaction filler, 12: partition, 13: ultrasonic transducer, 14: water retaining plate, 15: filter; 16: monitoring instrument. DETAILED DESCRIPTION

[0025] The present invention will be further described in detail below through the accompanying drawings and examples. Through these descriptions, the features and advantages of the present invention will become more clear and distinct. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them.

[0026] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation to the present invention.

[0027] like Figures 1 to 4 As shown, the embodiment of the present invention discloses an ultrasonic anti-clogging permeable reactive wall, comprising a wall 1, an ultrasonic vibration plate 8 and an ultrasonic generator 9. The interior of the wall is hollow and the top is open. The wall is divided into a filling bin 2 and an ultrasonic vibration plate bin 3 by a partition 12. The partition is made of stainless steel. The filling bin is filled with PRB reactive filler 11. The ultrasonic vibration plate is installed in the ultrasonic vibration plate bin, and the ultrasonic vibration plate is electrically connected to the ultrasonic generator through a cable 10. In this embodiment, the ultrasonic vibration plate includes an ultrasonic vibration plate shell and ultrasonic transducers 13 arranged alternately on two opposite side walls of the ultrasonic vibration plate shell, and the ultrasonic transducer is electrically connected to the ultrasonic generator through a cable. A lifting ring 7 is provided on the top of the ultrasonic vibration plate; the ultrasonic vibration plate can be lifted out of the ultrasonic vibration plate bin for inspection.

[0028] In the process of implementing the above solution, the material of the ultrasonic vibration plate shell is stainless steel, and the ultrasonic transducer in the ultrasonic vibration plate can be started and stopped in a graded manner through graded wiring. When the PRB reaction filler is locally blocked, only the ultrasonic vibration plate in the blocked area can be turned on to reduce the system operation energy consumption.

[0029] Water holes 6 are provided on the water-facing surface of the wall, the water-receiving surface of the filling bin and the partition, but no water holes are provided on the water-receiving surface of the ultrasonic vibration plate bin; a vertically extending slot 4 is provided on the inner side of the water-facing surface of the wall, and a water baffle 14 or a filter screen 15 is detachably installed in the slot.

[0030] refer to Figure 1 The wall is positioned perpendicular to the groundwater flow direction and downstream of the pollution plume. When the PRB system is operating normally, a filter screen is installed in the slot. Most groundwater flows through the water holes and filter screen on the water-facing side of the wall and enters the packing silo. Through the interactions between the pollutants and the PRB reactive packing (precipitation, adsorption, oxidation-reduction, fixation, and biodegradation), pollutants are removed from the groundwater. A small amount of groundwater flows through the water holes and filter screen on the water-facing side of the wall and enters the ultrasonic vibrating plate silo. From there, it enters the packing silo through the water holes in the partition, where it reacts with the PRB reactive packing. After the PRB reactive packing 11 purifies the groundwater, it flows downstream through the water holes 6 on the back side of the wall, improving the quality of the groundwater passing through the wall 1. In specific implementations, an appropriate width can be reserved where the back side of the packing silo contacts the ultrasonic vibrating plate silo. This allows for a longer flow path within the PRB reactive packing, ensuring effective pollutant removal. Groundwater entering the ultrasonic vibrating plate silo enhances the propagation and diffusion of ultrasound waves while minimizing energy loss.

[0031] When the PRB reaction filler is clogged, the ultrasonic generator 9 is turned on to generate a high-frequency signal which is transmitted to the ultrasonic transducer 13 via the cable 10. The ultrasonic transducer 13 converts the high-frequency signal into ultrasonic vibrations. The ultrasonic waves generate extremely strong shock waves and microjets, which remove the passivation layer formed on the surface of the PRB reaction filler during the degradation process with their vibration and stirring effects, strengthen the reduction degradation reaction on the interface, and improve the removal rate. At the same time, the PRB reaction filler, due to its large specific surface area and strong adsorption capacity, can adsorb the microbubbles generated by ultrasonic cavitation on its surface, further strengthening the cavitation effect of the ultrasonic wave, effectively inhibiting the reproduction of microorganisms, peeling off the sediment accumulated on the PRB reaction filler, and expanding the gaps between the PRB reaction filler particles, thereby improving the permeability of the PRB reaction filler and ensuring the efficient operation of the PRB system.

[0032] When the PRB reaction packing 11 in the packing bin 2 absorbs a large amount of pollutants and needs to be replaced or the ultrasonic vibration plate needs to be repaired, the filter 15 is removed from the slot 4 and the water baffle 14 is inserted to temporarily intercept the groundwater. The reacted PRB reaction packing 11 is dug out and replaced, or the ultrasonic vibration plate 7 is lifted out for repair. After the PRB reaction packing 11 is replaced or the ultrasonic vibration plate 7 is repaired, the water baffle 14 is removed from the slot 4 and replaced with the filter 15, and the PRB system continues to operate.

[0033] like Figure 2 As shown, a monitoring well 5 is provided at the center of the filling bin, and a monitor 16 is installed in the monitoring well. In the process of implementing the above scheme, the size of the monitoring well should be sufficient to accommodate the monitoring equipment. Generally, a smaller well is used, preferably a well with a diameter of 2.5 cm or 5 cm, so as to minimize the damage of the monitoring well to the flow field inside and around the PRB. The monitor is used to monitor the groundwater flow and water level inside each filling bin, and to promptly detect the reduction of pores and deterioration of permeability caused by barrier blockage. When the PRB reaction packing is passivated or the sediment accumulates, resulting in a reduction in the processing efficiency of the PRB system or even blockage, the specific situation of the passivation or blockage of the PRB reaction packing can be determined based on the water quality test results and the data fed back by the monitor.

[0034] The advantages of this application are described below with specific examples:

[0035] Example 1

[0036] At a pesticide factory contaminated site, the primary pollutants were chlorinated organic compounds. Groundwater flow within the site was controlled by topography, exhibiting a south-to-north flow pattern. To prevent the spread of pollutants, an ultrasonically anti-clogging permeable reaction wall was installed downstream of the groundwater runoff. The wall was 18 meters long, 1.2 meters thick, and 7 meters deep. The wall was filled with a PRB (Peripheral Reaction Barrier) filler consisting of a uniform mixture of 90% (by mass) micronized zero-valent iron and 10% (by mass) zeolite.

[0037] After the system was in operation for 70 days, the groundwater flow rate was monitored to be significantly lower than that at the beginning of the system operation. The PRB reaction filler was sampled and tested, and the porosity decreased from 0.58 to 0.36, and the permeability decreased from 6.3×10-8cm 2 Reduced to 2.6×10-9cm 2 Scanning electron microscopy revealed a 45-60 μm thick passive corrosion layer on the surface of the zero-valent iron particles. This indicates that the PRB reactive filler is clogged, resulting in reduced permeability, slower pollution plume treatment, and decreased reactive barrier operating efficiency.

[0038] After confirming that the filler is blocked, the ultrasonic vibration plate is turned on. One week later, the PRB reaction filler is sampled and tested again. The porosity increases from 0.36 to 0.52, and the permeability increases from 2.6×10-9cm 2 Increased to 5.4×10-8cm 2 The passive corrosion layer on the surface of the zero-valent iron particles has been reduced from 45-60μm to 6-15μm. The operating efficiency of the reaction barrier has basically returned to its optimal level.

[0039] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the utility model and are not limiting. Although the utility model is described in detail with reference to the preferred embodiments, ordinary technicians in this field should understand that the technical solution of the utility model can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution of the utility model, which should be included in the scope of the claims of the utility model.

Claims

1. An ultrasonic anti-clogging permeable reaction wall, characterized by: The ultrasonic vibration plate comprises a wall, an ultrasonic generator, wherein the interior of the wall is hollow and the top is open, and the wall is divided into a stuffing bin and an ultrasonic vibration plate bin by a partition. The stuffing bin is filled with PRB reaction stuffing, and the ultrasonic vibration plate is installed in the ultrasonic vibration plate bin, and the ultrasonic vibration plate is electrically connected to the ultrasonic generator through a cable; water holes are provided on the water-facing surface of the wall, the water-repelling surface of the stuffing bin and the partition.

2. The ultrasonic anti-clogging permeable reactive wall according to claim 1, characterized in that: A vertically extending slot is provided on the water-facing surface of the wall, and a water baffle or a filter screen is detachably mounted in the slot.

3. The ultrasonic anti-clogging permeable reactive wall according to claim 2, characterized in that: A monitoring well is provided at the center of the filling bin, and a monitoring instrument is installed in the monitoring well.

4. The ultrasonic anti-clogging permeable reactive wall according to claim 1, characterized in that: A hanging ring is provided on the top of the ultrasonic vibration plate.

5. The ultrasonic anti-clogging permeable reactive wall according to any one of claims 1 to 4, characterized in that: The ultrasonic vibration plate includes an ultrasonic vibration plate housing and ultrasonic transducers staggeredly arranged on two opposite side walls of the ultrasonic vibration plate housing. The ultrasonic transducers are electrically connected to the ultrasonic generator via a cable.

6. The ultrasonic anti-clogging permeable reactive wall according to claim 5, characterized in that: The materials of the partition and the ultrasonic vibration plate shell are both stainless steel.

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