Device for repairing underground water close to polluted site of river and application

Abstract

The invention discloses an underground water remediation device close to a polluted site of a river and application, the underground water remediation device comprises a front water blocking plate, a low-permeability water guide area, a middle-permeability water guide area, a high-permeability water guide area, straight water baffles on two sides, an active material wall reaction area and arc-shaped water baffles on two sides, the active material wall reaction area is in a circular arc shape, and the active material wall reaction area is filled with an active material; the straight water baffles on the two sides are arranged at the tail end of the active material wall reaction area; the front water blocking plate is arranged between the wall reaction area and the river and is arranged in an arc shape, and the inner arc faces the river; arc-shaped water baffles are arranged on the two sides between the front water baffle and the wall reaction area, a narrow water outlet is formed by the side close to the wall and the straight water baffle, a wide water outlet is formed in the position close to the front water baffle, and horn-shaped water outlet holes are formed in the arc-shaped water baffles; and three water guide areas with different permeability coefficients are arranged in the inner spaces of the wall body, the front water blocking plate and the arc-shaped water blocking plates on the two sides. According to the permeable reactive wall, the problem that active reaction media in the wall are consumed by substances in a surface water body after water level fluctuation surface water penetrates through the permeable reactive wall in the remediation process of underground water pollution of a river-adjacent site can be effectively solved.

Description

Technical Field

[0001] The present invention belongs to the field of groundwater pollution remediation, and specifically relates to a permeable reaction wall device and application for groundwater remediation in a polluted site near a river. Background Art

[0002] As an important component of my country's water resources, groundwater quality safety has become an important guarantee for economic development. However, with the rapid development of my country's economy, groundwater has been polluted to varying degrees due to human activities. There are many sources of groundwater pollution, such as industrial and mining enterprises, agricultural production, and urban solid waste disposal sites. Under normal circumstances, once groundwater is polluted, pollutants will exist for a long time due to the influence of the groundwater's own environment, and the risk to the surface water environment will increase. For this reason, groundwater pollution remediation technology has gradually attracted the attention of scientific researchers, and application research on some technologies has been carried out.

[0003] At present, groundwater remediation technology is divided into ex situ remediation and in situ remediation. Ex situ remediation is mainly an extraction treatment technology, which is suitable for sites with high pollutant concentration, large range and deep burial. The early remediation efficiency is high and the treatment volume is large, but its disadvantages are also prominent, mainly because pollutant tailing and rebound are prone to occur in the later stage, which has a great interference on the groundwater flow field and water environment. There are many types of in situ treatment technologies, among which the permeable reactive barrier (PRB) technology has the advantages of achieving in situ remediation, having little impact on surface structures, being able to treat a variety of pollutants, and having long-term treatment capabilities. Therefore, the research on PRB technology in China has gradually increased. One of the keys to PRB technology is the selection of active reaction medium (remediation filler). Commonly used remediation fillers include zero valent iron (ZVI), iron oxides and hydroxides, organic fillers (such as activated carbon), alkaline chelating agents, phosphate minerals, silicates, zeolites, clays, ion exchange resins, microorganisms and polymers. In addition to the determination of the active reaction medium, another key technology is how to set up the PRB wall in practical applications. At present, the types of PRB walls are mainly divided into: continuous PRB, funnel-gate PRB, injection reaction zone PRB, and reaction unit passive collection PRB. Among them, the continuous PRB is a PRB with a simple structure and convenient design and installation. It is set perpendicular to the groundwater flow direction and is suitable for sites with shallow groundwater levels and small pollution plumes. The funnel-gate PRB is composed of a low-permeability water-blocking wall (funnel) and a reaction medium (water gate) with permeability. It is suitable for sites with shallow groundwater levels and large pollution plumes. The injection reaction zone PRB uses several overlapping injection wells in the treatment area to inject active reaction media to form a belt-shaped reaction area to remove pollutants in the groundwater flowing through the reaction area. The reaction unit passive collection PRB introduces groundwater flow into the reaction unit constructed with the reaction medium through a collection trough. It is suitable for sites with a wide pollution plume. However, the above types of PRBs have limitations and are difficult to apply to the diversity of groundwater types. In particular, the problem of remediation of polluted groundwater near rivers in the south is that the groundwater in such areas is shallow, greatly affected by rivers or lakes, and easily affected by surface water recharge. When this happens, after the surface water passes through the wall, the active reaction medium in the PRB wall will be consumed by the substances in the surface water body, resulting in the subsequent active reaction medium repair failing to meet expectations. Summary of the invention

[0004] In view of the problems of rapid ineffective consumption of active materials in the wall and high repair cost caused by the above-mentioned traditional type of PRB repair of groundwater pollution in river-prone polluted sites due to the influence of surface water, the present invention provides a permeable reaction wall device and application for groundwater repair in polluted sites near rivers, which adopts a multi-layer water-blocking design to prevent surface water from passing through the PRB wall during the process of groundwater recharge.

[0005] The technical solution adopted by the present invention to solve the technical problem is: A groundwater remediation device for a contaminated site near a river comprises a front water blocking plate, an arc water blocking plate and a straight water blocking plate which are arranged in sequence from front to back, wherein the front water blocking plate is arranged at one side of the river and is arranged in an arc shape with the inner arc facing the river, the arc water blocking plate and the straight water blocking plate are symmetrically arranged behind the front water blocking plate, respectively, with a wall reaction zone arranged therebetween, the wall reaction zone is arranged in an arc shape with the inner arc facing away from the river, and the interior of the wall reaction zone is filled with active materials, and the inner spaces of the wall reaction zone, the front water blocking plate and the arc water blocking plates on both sides are provided with three water conducting zones with different permeability coefficients, which are divided into a low permeability water conducting zone, which has the same permeability coefficient as the wall reaction zone; a medium permeability water conducting zone, whose permeability coefficient is 1.5-3 times that of the low permeability water conducting zone; and a high permeability water conducting zone, whose permeability coefficient is 1.5-3 times that of the medium permeability water conducting zone.

[0006] As an improvement of the above technical solution, the permeability coefficient of the wall reaction zone is higher than that of the surrounding contaminated aquifer.

[0007] As an improvement of the above technical solution, the straight water retaining plates are arranged at the ends of both sides of the wall reaction zone.

[0008] As an improvement of the above technical solution, the arc-shaped water retaining plate forms a narrow water outlet on the side close to the wall reaction area and the straight water retaining plate, and forms a wide water outlet on the side close to the front water blocking plate.

[0009] As an improvement of the above technical solution, a plurality of trumpet-shaped water outlet holes are arranged on the arc-shaped water retaining plate, which are small water outlets facing outwards and large water outlets facing inwards.

[0010] As an improvement of the above technical solution, the low permeability water conducting area is filled with quartz sand.

[0011] As an improvement of the above technical solution, the medium permeability water conducting area is filled with quartz sand with larger particles.

[0012] As an improvement of the above technical solution, the high permeability water-conducting area is filled with zeolite.

[0013] The beneficial effects brought by the present invention are: The present invention takes into account the hydraulic conditions of the mutual replenishment of groundwater and surface water near the river, and adopts different types of water blocking plates and permeable area combinations to avoid the problem of surface water passing through the wall reaction area during the surface water replenishment process. At the same time, the use of trumpet-shaped water outlet holes and arc-shaped front water blocking plates can solve the problem of groundwater being blocked from external discharge after passing through the reaction wall. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

[0015] Figure 1 is a schematic top view of the device of the present invention; Figure 2 It is a schematic diagram of an arc-shaped water retaining plate; Figure 3 It is a schematic diagram of the trumpet-shaped water outlet structure on the arc-shaped water retaining plate; Figure 4 It is a schematic diagram of the application of the present invention; Numbers in the figure: 1—front water blocking plate; 2—low permeability water conducting area; 3—medium permeability water conducting area; 4—high permeability water conducting area; 5—straight water retaining plate; 6—wall reaction area; 7—arc-shaped water retaining plate; 8—trumpet-shaped water outlet; 9—large water outlet; 10—small water outlet; 11—river; 12—groundwater flow direction; 13—polluted plume. DETAILED DESCRIPTION

[0016] The following will be combined with the embodiments of the present invention and the accompanying drawings to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0017] Example 1 A groundwater remediation device for a polluted site near a river, which consists of a front water blocking plate 1, a low permeability water guide area 2, a medium permeability water guide area 3, a high permeability water guide area 4, straight water blocking plates 5 on both sides, an active material wall reaction area 6, and arc-shaped water blocking plates 7 on both sides. Among them, the active material wall reaction area 6 is in an arc shape, filled with active materials inside, and its permeability coefficient is higher than that of the surrounding polluted aquifers; the straight water blocking plates 5 on both sides are arranged at the ends of the active material wall reaction area 6; the front water blocking plate 1 is arranged between the wall reaction area 6 and the river 11, and is arranged in an arc shape, with the inner arc facing the river 11; arc-shaped water blocking plates 7 are arranged on both sides between the front water blocking plate 1 and the wall reaction area 6, a narrow water outlet is formed on the side close to the wall reaction area 6 and the straight water blocking plate 5, and a wide water outlet is formed on the side close to the front water blocking plate 1, and a trumpet-shaped water outlet hole 8 is arranged on the arc-shaped water blocking plate 7, with a small water outlet 10 facing outward and a large water outlet 9 facing inward.

[0018] Three water guide areas with different permeability coefficients are set in the internal space of the wall reaction zone 6, the front water blocking plate 1 and the arc-shaped water retaining plates 7 on both sides, which are divided into a low permeability water guide area 2 filled with quartz sand, which has the same permeability coefficient as the active material wall reaction zone 6; a medium permeability water guide area 3 filled with quartz sand with larger particles, and its permeability coefficient is 1.5-3 times that of the low permeability water guide area 2; and a high permeability water guide area 4 filled with zeolite, and its permeability coefficient is 1.5-3 times that of the medium permeability water guide area 3.

[0019] Example 2 The groundwater remediation device for contaminated sites near rivers is applied to the remediation of groundwater pollution near rivers in the south.

[0020] First, a suitable space is selected between the groundwater pollution plume 13 and the river 11 of the polluted riverside site to set up an arc-shaped wall reaction zone 6, whose permeability coefficient exceeds the aquifer of the polluted site, and lateral straight water retaining plates 5 are set on the outer sides of the two ends to block the river water from replenishing the polluted area and prevent the pollution plume 13 from overflowing and not passing through the wall reaction zone 6.

[0021] Secondly, a front water blocking plate 1 is arranged between the wall reaction area 6 and the river 11, which is arranged in an arc shape, with the inner arc facing the river 11, and arc-shaped water retaining plates 7 are arranged on both sides between the front water blocking plate 1 and the wall reaction area 6, and a narrow water outlet is formed with the straight water retaining plate 5 on the side close to the wall reaction area 6, and a wide water outlet is formed on the side close to the front water blocking plate 1, and a trumpet-shaped water outlet hole 8 is arranged on the arc-shaped water retaining plate 7, which is a large water outlet 9 inwardly and a small water outlet 10 outwardly; in the wall reaction area 6, the front water blocking plate 7 is arranged in an arc shape, and the inner arc shape is arranged in an arc shape. Three water guide areas with different permeability coefficients are set in the internal space of the plate 1 and the arc-shaped water retaining plates 7 on both sides, which are divided into a low permeability water guide area 2 filled with quartz sand, which has a permeability coefficient consistent with that of the active material wall reaction area 6; a medium permeability water guide area 3 filled with quartz sand with larger particles, whose permeability coefficient is twice that of the low permeability water guide area; a high permeability water guide area 4 filled with zeolite, whose permeability coefficient is twice that of the medium permeability water guide area, and is set at the narrow water outlet between the arc-shaped water retaining plate 7 and the straight water retaining plate 5.

[0022] Finally, when the water level of the river 11 is higher than the groundwater level where the groundwater contamination plume 13 is located, the replenishment water flow direction 12 is blocked by the front water blocking plate 1, and the unblocked water will flow along the arc-shaped water blocking plate 7. After entering the three water guide areas with different permeability coefficients, it will first enter the medium permeability water guide area 3 through the low permeability water guide area 2 and then be discharged from the high permeability water guide area 4 due to the different permeability coefficients, thereby avoiding the problem of active material consumption caused by pollutants in the river 11 water passing through the wall reaction area 6. In addition, when the area of ​​the contaminated plume 13 is large, multiple devices can be discharged in parallel to capture more contaminated plumes 13.

[0023] It should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. Groundwater remediation device for polluted sites near rivers, characterized by: It comprises a front water blocking plate, an arc water blocking plate and a straight water blocking plate which are arranged in sequence from front to back. The front water blocking plate is arranged on one side of the river and is arranged in an arc shape with the inner arc facing the river. The arc water blocking plate and the straight water blocking plate are symmetrically arranged behind the front water blocking plate, respectively, with a wall reaction zone arranged therebetween. The wall reaction zone is arranged in an arc shape with the inner arc facing away from the river and is filled with active materials. Three water guiding zones with different permeability coefficients are arranged in the inner space of the wall reaction zone, the front water blocking plate and the arc water blocking plates on both sides, which are divided into a low permeability water guiding zone, which has the same permeability coefficient as the wall reaction zone; a medium permeability water guiding zone, whose permeability coefficient is 1.5-3 times that of the low permeability water guiding zone; and a high permeability water guiding zone, whose permeability coefficient is 1.5-3 times that of the medium permeability water guiding zone.

2. The groundwater repair device according to claim 1, characterized in that: The permeability coefficient of the wall reaction zone is higher than that of the surrounding contaminated aquifer.

3. The groundwater repair device according to claim 1, characterized in that: The straight water retaining plates are arranged at the ends of both sides of the wall reaction zone.

4. The groundwater repair device according to claim 1, characterized in that: The arc-shaped water retaining plate forms a narrow water outlet on the side close to the wall reaction area and the straight water retaining plate, and forms a wide water outlet on the side close to the front water blocking plate.

5. The groundwater repair device according to claim 1, characterized in that: The arc-shaped water retaining plate is provided with a plurality of trumpet-shaped water outlet holes, which are small water outlets facing outwards and large water outlets facing inwards.

6. The groundwater repair device according to claim 1, characterized in that: The low permeability water-conducting area is filled with quartz sand; The medium permeability water conducting area is filled with quartz sand with larger particles; The high permeability water-conducting area is filled with zeolite.

7. Application of the groundwater remediation device for a contaminated site near a river according to any one of claims 1 to 6 in the remediation of groundwater pollution near a river, characterized in that: include First, a wall reaction zone is set up between the groundwater pollution plume and the river at the polluted riverside site, with a permeability coefficient exceeding the aquifer of the polluted site, and lateral straight water retaining plates are set up on the outside of the two ends to block the river water from replenishing the polluted area and avoid the pollution plume from overflowing and not passing through the wall reaction zone; Secondly, a front water blocking plate is arranged between the wall reaction zone and the river, arranged in an arc shape, with the inner arc facing the river, and arc-shaped water retaining plates are arranged on both sides between the front water blocking plate and the wall reaction zone, and a narrow water outlet is formed with the straight water retaining plate on the side close to the wall reaction zone, and a wide water outlet is formed on the side close to the front water blocking plate; three water guide areas with different permeability coefficients are arranged in the inner space of the wall reaction zone, the front water blocking plate and the arc-shaped water retaining plates on both sides, which are a low permeability water guide area filled with quartz sand, a medium permeability water guide area filled with quartz sand with larger particles, and a high permeability water guide area filled with zeolite; Finally, when the river water level is higher than the groundwater level where the groundwater pollution plume is located, the flow of replenishment water is blocked by the front water blocking plate. The unblocked water will flow along the arc-shaped water blocking plate. After some of it enters the three water diversion areas with different permeability coefficients, it will be affected by the different permeability coefficients and will first enter the medium permeability water diversion area through the low permeability water diversion area, and then be discharged from the high permeability water diversion area, avoiding the problem of active material consumption caused by pollutants in the river water passing through the wall reaction area. When the area of ​​the polluted plume is large, multiple remediation devices can be discharged in parallel to capture more polluted plumes.

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