An artificial groundwater recharge system

Abstract

This invention proposes an artificial groundwater recharge system, comprising a surface water source, an infiltration channel, a multi-stage filtration and recharge unit, and an anti-clogging unit. The infiltration channel connects the surface water source and the multi-stage filtration and recharge unit, with a length 2.5 to 4.0 times the straight-line distance, and is arranged in a tortuous pattern. A grid structure is installed at the front end of the infiltration channel. The multi-stage filtration and recharge unit includes at least a filter, multiple filter layers, a well, and multiple annular filter media layers, with the top of the annular filter media layers lower than the top plate of the confined aquifer. The anti-clogging unit includes a controller, an electric control valve, and a pumping pipe. The electric control valve and the pumping pipe are respectively connected to the controller. The electric control valve is located between the filter and the filter layers. The pumping pipe is located inside the well, and its outlet is connected to the surface water source. Pressure sensors and flow sensors on the well wall are communicatively connected to the controller. This invention achieves coordinated recharge of deep and shallow groundwater, improves water resource utilization efficiency, and simultaneously enhances filtration efficiency and reduces the risk of clogging.

Description

Technical Field

[0001] This invention relates to the field of groundwater remediation technology, specifically to an artificial groundwater recharge system. Background Technology

[0002] As a major grain-producing area and densely populated region in my country, the plains face significant challenges due to the uneven spatial and temporal distribution of water resources. Seasonal droughts, groundwater over-extraction leading to water level declines, and aquifer depletion severely restrict regional agricultural production, residential water security, and ecological stability. Existing groundwater recharge technologies mostly employ a single direct-injection well model. However, in practical applications, these technologies suffer from several problems: unclear surface water recharge pathways leading to water loss and low resource utilization rates; unreasonable recharge filtration layer design causing secondary pollution and filter blockage; and a lack of efficient blockage control solutions hindering continuous and stable recharge. Summary of the Invention

[0003] This invention proposes a groundwater artificial recharge system that can achieve a combination of shallow natural recharge in infiltration channels and deep precise recharge in wells, enabling coordinated recharge of shallow and deep groundwater, improving water resource utilization efficiency, while also increasing filtration efficiency and reducing the risk of blockage, and avoiding secondary pollution of groundwater.

[0004] To solve the above-mentioned technical problems, the present invention proposes a groundwater artificial recharge system, including a surface water source, at least one infiltration channel, at least one multi-stage filtration recharge unit, and at least one anti-clogging unit. The infiltration channel connects the surface water source and the multi-stage filtration and recharge unit, and the infiltration channel is arranged in a tortuous manner; the length of the infiltration channel is 2.5 to 4.0 times the straight-line distance between the surface water source and the multi-stage filtration and recharge unit; a grid structure is provided at the connection between the surface water source and the infiltration channel; Starting from the outlet end of the infiltration channel, the multi-stage filtration and reinjection unit includes at least a filter, a filter layer, a well, and an annular filter media layer. The well includes a well wall pipe and a filter pipe. The annular filter media layer wraps around the outside of the filter pipe. The filter layer and the annular filter media layer each have multiple layers. The top of the annular filter media layer is higher than or level with the top of the filter pipe, but lower than the top plate of the confined aquifer. The anti-clogging unit includes a controller, an electric control valve, and a water pumping pipe. The controller is installed on the ground, and the electric control valve and the water pumping pipe are respectively connected to the controller. The electric control valve is installed between the filter and the filter layer, and the water pumping pipe is installed in the well, with the outlet of the water pumping pipe connected to the surface water source. A pressure sensor and a flow sensor are installed on the well casing, and the pressure sensor and the flow sensor are respectively connected to the controller.

[0005] In one embodiment of the present invention, the infiltration channel is arranged in a curved or zigzag shape, the design water level of the infiltration channel is lower than the water level of the surface water source, the bottom of the infiltration channel is lower than the water level of the surface water source; and / or, a graded medium-coarse sand filter layer is laid at the bottom of the infiltration channel.

[0006] In one embodiment of the present invention, the bottom of the infiltration channel is set in a stepped shape, and the depth gradually increases along the direction of water flow.

[0007] In one embodiment of the present invention, the spacing between adjacent multi-stage filtration reinjection units is greater than or equal to twice the influence radius of the well.

[0008] In one embodiment of the present invention, the multi-stage filtration and reinjection unit further includes a top cover, an equipment layer, and a support layer. The top cover engages with the wellhead of the well. The equipment layer is disposed at the bottom of the wellhead and on the support layer. The filter and the filtration layer are disposed within the equipment layer.

[0009] In one embodiment of the present invention, the filter includes an inlet end, a first pressure detector, a side opening, a second pressure detector, a filter body, and an outlet end. The inlet end and the outlet end are disposed opposite to each other at both ends of the filter. The inlet end is connected to the outlet end of the infiltration channel. The first pressure detector is disposed near the inlet end, and the second pressure detector is disposed near the outlet end. The filter body is removed through the side opening. The first pressure detector and the second pressure detector are respectively connected to the controller.

[0010] In one embodiment of the present invention, the filter layer includes an inlet, a first filter layer, a second filter layer, a third filter layer and an outlet arranged sequentially. The inlet is connected to the outlet end of the filter, and the outlet extends through the equipment layer and the support layer into the manhole. The first filter layer is removed by opening the top cover.

[0011] In one embodiment of the present invention, the well further includes a sedimentation pipe, the well wall pipe is disposed above the water filter pipe, and the sedimentation pipe is disposed below the water filter pipe; a submersible pump is disposed at the bottom of the pumping pipe, the submersible pump is located inside the water filter pipe, and the submersible pump is communicatively connected to the controller.

[0012] In one embodiment of the present invention, the annular filter media layer includes a first annular filter media layer, a second annular filter media layer and a third annular filter media layer stacked sequentially. The first annular filter media layer is disposed adjacent to the water filter pipe, and the particle size of the filter media decreases from the first annular filter media layer to the third annular filter media layer.

[0013] In one embodiment of the present invention, the anti-clogging unit includes an intermittent backflow mode, wherein the controller regulates the opening and closing of the electric control valve; the anti-clogging unit includes a backflushing mode for the pumping pipe, wherein the controller regulates the opening and closing of the submersible pump.

[0014] In summary, this invention proposes an artificial groundwater recharge system that enables natural infiltration during the water diversion process to replenish shallow groundwater, lengthening the actual flow path of water in the infiltration channel and significantly improving the shallow infiltration effect. Simultaneously, it rapidly replenishes deep aquifers through wells, balancing recharge rate and coverage. This system prevents groundwater pollution caused by recharge at the source, alleviates well blockage, significantly extends system lifespan, reduces operation and maintenance costs, and achieves efficient regional water resource regulation and sustainable groundwater recharge. Through multi-stage filtration and anti-clogging design, non-point source pollutant interception and water purification are achieved simultaneously during recharge, improving filtration efficiency and reducing the risk of blockage, thus preventing secondary groundwater pollution. By constructing a three-dimensional coordinated recharge system of surface water source-infiltration channel-well, a combined mode of shallow natural recharge through infiltration channels and deep precise recharge through wells is achieved, enabling coordinated recharge of shallow and deep groundwater and improving water resource utilization efficiency. This system can alleviate the spatial and temporal mismatch of water resources in plain areas, particularly during flood season and drought season. The reinjection system requires no large-scale civil engineering construction and can be quickly implemented based on existing river channels and well clusters. This reduces the construction cost per well, resulting in significant advantages in versatility and cost. Attached Figure Description

[0015] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 This is a schematic diagram of an artificial groundwater recharge system before recharge in one embodiment of the present invention.

[0017] Figure 2 This is a schematic diagram of a multi-stage filtration and recharge unit in one embodiment of the present invention.

[0018] Figure 3 This is a schematic diagram of a filter and a filter layer in one embodiment of the present invention.

[0019] Figure 4 This is a schematic diagram of an artificial groundwater recharge system after recharge in one embodiment of the present invention.

[0020] Figure 5 This is a schematic diagram of a multi-stage filtration and recharge unit during backwashing in one embodiment of the present invention.

[0021] Label Explanation: 10. Surface water source; 11. Second impermeable layer; 12. Medium-fine sand layer; 13. First impermeable layer; 14. Silt-fine sand layer; 15. Top layer; 20. Infiltration channel; 30. Multi-stage filtration and recharge unit; 31. Top cover; 311. Wellhead; 321. Equipment layer; 322. Support layer; 33. Filter; 331. Inlet; 332. First pressure detector; 333. Side opening; 334. Second pressure detector; 335. Filter body; 336. Outlet; 34. Filter layer; 341. Inlet; 3 42. First filter layer; 343. Second filter layer; 344. Third filter layer; 345. Outlet; 35. Backfill section; 36. Clay water-stopping section; 37. Well; 371. Well wall pipe; 372. Filter pipe; 373. Sedimentation pipe; 38. Annular filter media layer; 381. First annular filter media layer; 382. Second annular filter media layer; 383. Third annular filter media layer; 41. Pumping pipe; 42. Submersible pump; 43. Pressure sensor; 44. Flow sensor; 50. Controller; 51. Electric control valve. Detailed Implementation

[0022] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein in the specification of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of this application.

[0024] In the description of this specification, it should be understood that the terms "center," "upper," "lower," "front," "rear," "left," and "right," etc., indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings and are only for the convenience of describing this solution and simplifying the description, and do not indicate or imply that the device or component referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on this solution. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0025] Please see Figures 1 to 3As shown, this application provides a groundwater artificial recharge system, including a surface water source 10, at least one infiltration channel 20, at least one multi-stage filtration recharge unit 30, and at least one anti-clogging unit. The infiltration channel 20 is located between the surface water source 10 and the multi-stage filtration recharge unit 30, and the infiltration channel 20 is arranged in a tortuous manner. Starting from the outlet end of the infiltration channel 20, the multi-stage filtration recharge unit 30 includes at least a filter 33, a filter layer 34, a well 37, and an annular filter media layer 38. The annular filter media layer 38 wraps around a portion of the well 37. The anti-clogging unit includes a controller 50, an electric control valve 51, and a pumping pipe 41. The electric control valve 51 and the pumping pipe 41 are respectively connected to the controller 50. The electric control valve 51 is located between the filter 33 and the filter layer 34. The pumping pipe is located inside the well 37, and the outlet of the pumping pipe 41 is connected to the surface water source 10. The groundwater artificial recharge system of this application enables natural infiltration during the water diversion process to replenish shallow groundwater, while simultaneously replenishing deep aquifers through wells. It balances recharge rate and coverage, preventing groundwater pollution caused by recharge at the source, alleviating well blockage problems, significantly extending system lifespan, reducing operation and maintenance costs, and achieving efficient regulation and storage of regional water resources and sustainable groundwater replenishment.

[0026] Please see Figure 1 As shown, in one embodiment of the present invention, the surface water source 10 is, for example, an existing natural river or an artificial irrigation canal. The river inlet area needs to be dredged and modified to remove a 0.5m to 1.0m thick layer of sediment to prevent endogenous pollutants from entering the recharge system. A 5mm to 10mm aperture grid structure is installed at the connection between the surface water source and the infiltration channel to intercept large floating objects such as fallen leaves, household waste, etc. The water source in the surface water source 10 mainly comes from surface runoff formed by rainfall during the flood season. In other embodiments, depending on regional resource conditions, the surface water source 10 may be, for example, a reservoir, lake, pond, or small regulating reservoir.

[0027] Please see Figure 1 As shown, in one embodiment of the present invention, based on the hydrogeological conditions within the recharge area, the stratigraphic information obtained through core drilling includes, from the surface, a topsoil layer 15, a silty sand layer 14, a first impermeable layer 13, a medium-fine sand layer 12, and a second impermeable layer 11, etc. In this embodiment, the groundwater level is located, for example, on the silty sand layer 14, and the confined water level is located, for example, within the silty sand layer 14.

[0028] Please see Figure 1As shown, in one embodiment of the present invention, the infiltration channel 20 is arranged in a curved or zigzag shape, or in an S-shape. In this embodiment, the zigzag infiltration channel is arranged with a zigzag direction of 120° to 150°, and its construction difficulty is lower than that of the S-shaped infiltration channel. By setting the tortuous infiltration channel 20, the hydraulic path can be extended. The infiltration channel 20 is set downward from the ground surface, and the design water level of the infiltration channel 20 is, for example, 0.2m to 0.3m lower than the water level of the surface water source 10. The bottom of the infiltration channel 20 is 0.8m to 1m lower than the water level of the surface water source 10, ensuring that the water in the surface water source 10 can flow into the infiltration channel 20 by gravity without the need for additional pumping devices. By constructing infiltration channels based on any surface water source such as rivers, ponds, and reservoirs, gravity-fed water conveyance can be achieved without additional power equipment. It can be directly adapted to the renovation of existing river channels and agricultural irrigation well groups in plain areas. No large-scale civil engineering construction is required. It can be quickly implemented based on existing river channels and well group facilities, reducing the construction cost per well. Its universality and cost advantages are prominent.

[0029] Please see Figure 1 As shown, in one embodiment of the present invention, the design depth of the infiltration channel 20 is based on the actual area. The top of the infiltration channel 20 is 0.1m to 0.2m above the ground surface to prevent backflow of surface sewage. The bottom of the infiltration channel 20 is covered with a 0.1m to 0.2m thick graded medium-coarse sand filter layer. The graded medium-coarse sand filter layer is, for example, a mixture of medium-coarse sand with a particle size of 0.25mm to 2mm and natural fine sand with a particle size ≤0.25mm in a mass ratio of 9:1 to 8:2. The mass ratio of coarse sand (0.5mm to 2mm), medium sand (0.35mm to 0.5mm), and fine sand (0.25mm to 0.35mm) in the medium-coarse sand is, for example, 5 to 6:2 to 3:1 to 2. The cross-section of the infiltration channel may adopt a trapezoidal design, with a top width of 1.0m to 1.5m, a bottom width of 0.6m to 0.8m, and a slope of 1:0.8 to 1:0.5, where the slope is the ratio of vertical height to horizontal projected length. By designing the cross-sectional shape of the infiltration channel, the structural stability of the channel can be ensured, and maintenance and dredging can be facilitated. Compared with traditional closed water conveyance pipelines, the open infiltration channel in this application allows water to naturally infiltrate during the water diversion process, directly replenishing shallow groundwater. At the same time, the bottom of the channel can act as a natural filter for the water. Combined with the tortuous design, the actual flow path of water in the infiltration channel is lengthened, significantly improving the shallow infiltration effect.

[0030] Please see Figure 1As shown, in one embodiment of the present invention, the straight-line distance between the surface water source 10 and the multi-stage filtration and recharge unit 30 is, for example, 100m to 500m, and the length of the infiltration channel 20 is, for example, 2.5 to 4.0 times the straight-line distance between the surface water source 10 and the multi-stage filtration and recharge unit 30. Compared with a straight-line infiltration channel, the infiltration channel of this application can extend the hydraulic retention time to 30min to 120min. By controlling the ratio of the length of the infiltration channel 20 to the straight-line distance between the surface water source 10 and the multi-stage filtration and recharge unit 30, it is possible to ensure that the infiltration channel 20 has sufficient length to achieve natural purification, while avoiding ineffective evaporation loss of water during water conveyance. In this application, the specific distance of the infiltration channel is determined based on the permeability coefficient of the regional aquifer and the scale of single-well recharge. Part of the water introduced by the infiltration channel naturally infiltrates to replenish the unconfined aquifer, and part is injected into the deep aquifer through wells, forming a dual-layer linkage recharge mode of shallow and deep groundwater, which can significantly expand the coverage of water source recharge and significantly improve water resource utilization efficiency. This application innovatively adopts a three-dimensional coordinated recharge mode combining infiltration channels and multi-stage filtration and recharge units. The infiltration channels allow for natural infiltration during the water diversion process to replenish shallow groundwater, while simultaneously providing rapid recharge to deeper aquifers via wells. This balances recharge rate and coverage area, with a single system capable of supplying water to areas up to 4km long. 2 ~10km 2 The region's groundwater recharge needs and water resource utilization rate are more than 45% higher than the traditional pipeline water transmission and reinjection mode. The average annual rise in shallow groundwater level can reach 0.5m to 0.8m, while the average annual rise in deep groundwater level can reach 1m to 3m.

[0031] Please see Figure 1 As shown, in another embodiment of the present invention, the bottom of the infiltration channel 20 is, for example, stepped, and the depth gradually increases along the direction of water flow. In a specific embodiment of this application, the bottom depth of the infiltration channel 20 near the surface water source 10 is, for example, 0.8m to 1.0m below the normal water level, and the bottom depth of the infiltration channel 20 near the multi-stage filtration and recharge unit 30 is, for example, 1.5m to 2.0m below the normal water level. For every 100m increase in length, the depth of the infiltration channel increases by, for example, 0.1m to 0.2m, which allows the water to gradually deepen and infiltrate during the flow process, improving the uniformity of shallow groundwater recharge.

[0032] Please see Figures 1 to 2 As shown, in one embodiment of the present invention, a multi-stage filtration and reinjection unit 30 is disposed at the end of the infiltration channel 20 away from the surface water source 10. In the reinjection system, for example, multiple infiltration channels 20 and multiple multi-stage filtration and reinjection units 30 are disposed, with the multiple infiltration channels 20 and the multiple multi-stage filtration and reinjection units 30 being equidistantly arranged, and one infiltration channel 20 connected to one multi-stage filtration and reinjection unit 30. The distance between adjacent multi-stage filtration and reinjection units 30 is greater than or equal to twice the influence radius of the well. The influence radius... , where s wThe water level rise at the well wall when recharge is stable is expressed in meters (m), and K is the permeability coefficient, expressed in meters per day (m / d). The radius of influence R is the range of influence of the well on the surrounding groundwater during recharge. By controlling the spacing between adjacent multi-stage filtration and recharge units 30, the superposition of groundwater heads during multi-well recharge can be avoided. This ensures the efficiency of single-well recharge, expands the recharge coverage of deep groundwater, and effectively prevents geological risks caused by excessively high water pressure in local aquifers. In other embodiments, the distribution mode of the infiltration channel 20 and the multi-stage filtration and recharge unit 30 can be flexibly adjusted to a combination of one channel and multiple wells or multiple channels and one well. It can also be directly based on the existing irrigation canal system and agricultural well group, as long as the core function of three-dimensional coordinated recharge of deep and shallow groundwater is achieved. By constructing a three-dimensional coordinated recharge system of surface water source-infiltration channel-well, a combination mode of shallow natural recharge in infiltration channel and deep precise recharge in well is realized, achieving coordinated recharge of shallow and deep groundwater, improving water resource utilization efficiency, realizing the resource utilization of surface water source, and alleviating the problem of water resource mismatch in time and space during flood season and drought season in plain areas.

[0033] Please see Figures 1 to 2 As shown, in one embodiment of the present invention, the multi-stage filtration and reinjection unit 30 includes at least a filter 33, a filter layer 34, a well 37, and an annular filter media layer 38. The well 37 includes a well wall pipe 371, a water filter pipe 372, and a sedimentation pipe 373. The filter 33 is connected to the outlet end of the infiltration channel 20. The filter layer 34 is disposed at the outlet end of the filter 33. The well wall pipe 371 is disposed adjacent to the filter layer 34. The water filter pipe 372 is disposed at the end away from the filter layer 34. The sedimentation pipe 373 is disposed at the end of the water filter pipe 372 away from the well wall pipe 371. The annular filter media layer 38 wraps around the outside of the water filter pipe 372 and the sedimentation pipe 373. By employing at least a four-stage filtration structure including filters, filter layers, water filter pipes, and filter media, the comprehensive interception rate of suspended solids, ammonia nitrogen, and heavy metals in the water can reach over 92%, preventing groundwater pollution caused by reinjection from the source. The interception rate, for example, is obtained by sampling from surface water source 10 and well 37 and then testing them.

[0034] Please see Figure 2As shown, in one embodiment of the present invention, the multi-stage filtration reinjection unit 30 further includes a top cover 31. The top cover 31 is disposed on the top of the multi-stage filtration reinjection unit 30 and engages with the wellhead 311 of the well 37. The wellhead 311 refers to the part where the well pipe connects to the ground, and the top cover 31 can be opened and closed within the wellhead 311 to facilitate daily maintenance and replacement of filter materials. The wellhead 311 and the top cover 31 are, for example, formed of reinforced concrete. Below the wellhead 311, an equipment layer 321 and a support layer 322 are disposed. The equipment layer 321 is located at the bottom of the wellhead 311 and is disposed on the support layer 322. The equipment layer 321 is, for example, formed of hot-dip galvanized steel grating, stainless steel, or cast iron, and has an internal space for placing filters 33 and filter layers 34, etc. The support layer 322 is, for example, formed of concrete, stainless steel, etc., and is used to support filters 33 and filter layers 34, etc.

[0035] Please see Figures 1 to 3 As shown, in one embodiment of the present invention, the filter 33 and the filter layer 34 are disposed within the equipment layer 321, and the filter 33 and the filter layer 34 are arranged horizontally or vertically in sequence. The filter 33 is, for example, a stainless steel mesh filter, and includes, for example, an inlet end 331, a first pressure detector 332, a side opening 333, a second pressure detector 334, a filter body 335, and an outlet end 336. The inlet end 331 and the outlet end 336 are disposed opposite each other at both ends of the filter 33. The inlet end 331 is connected to the outlet end of the infiltration channel 20. The filter body 335 is, for example, a 304 stainless steel mesh, with a filtration accuracy of, for example, 80 mesh to 120 mesh, capable of intercepting residual silt and suspended particulate matter in the water. The first pressure detector 332 is located near the water inlet 331, and the second pressure detector 334 is located near the water outlet 336. They detect the pressure of the inlet and outlet water respectively, and the clogging status of the filter body 335 can be intuitively judged by the pressure difference. In this embodiment, for example, when the pressure difference detected by the first pressure detector 332 and the second pressure detector 334 reaches 0.1MPa, the top cover 31 and the side opening 333 are opened, and the filter body 335 is taken out for manual cleaning.

[0036] Please see Figures 1 to 3As shown, in one embodiment of the present invention, the filter layer 34 includes, for example, an inlet 341, a first filter layer 342, a second filter layer 343, a third filter layer 344, and an outlet 345. The first filter layer 342, the second filter layer 343, and the third filter layer 344 are disposed within a filter tank (not shown in the figure), and the inlet 341 and the outlet 345 are disposed at opposite ends of the filter tank. The inlet 341 is connected to the outlet end 336 of the filter 33, for example, through a threaded connection, welded connection, flange connection, socket connection, or compression connection. The outlet 345 extends through the equipment layer 321 and the support layer 322 into the manhole 37 to recharge the water that has passed through the filter 33 and the filter layer 34 back into the manhole 37. The first filter layer 342, the second filter layer 343, and the third filter layer 344 are sequentially disposed between the inlet 341 and the outlet 345. In this embodiment, the first filter layer 342 is, for example, a rigid polyurethane sponge, which intercepts suspended sediment and colloidal particles remaining after filtration, reducing the clogging pressure of subsequent functional layers. The second filter layer 343 is, for example, natural zeolite filter media, whose special internal pore structure can adsorb pollutants such as ammonia nitrogen. The third filter layer 344 is, for example, a biochar composite material, which can remove heavy metal ions from the water through adsorption and reduction. In this invention, the filter layer materials can be commercially available, and this application does not impose specific limitations on commercially available brands and models. In this embodiment, the thicknesses of the first filter layer 342, the second filter layer 343, and the third filter layer 344 are, for example, equal.

[0037] Please see Figures 1 to 3 As shown, in one embodiment of the present invention, the top cover 31 can be opened to remove the first filter layer 342 for high-pressure rinsing and reuse. Depending on the water quality, the first filter layer 342 is cleaned, for example, every 20 to 35 days. By cleaning the first filter layer 342, the filter media reuse rate can reach 70%, the filter layer clogging cycle can be extended to 3 to 4 years, the filter media replacement frequency can be reduced by 60%, and the annual maintenance cost can be reduced by 30%.

[0038] Please see Figures 1 to 3As shown, in one embodiment of the present invention, a manhole 37 is disposed below the support layer 322. The manhole 37 includes, for example, a manhole wall pipe 371, a filter pipe 372, and a sedimentation pipe 373. The manhole wall pipe 371 is disposed above the filter pipe 372, and the sedimentation pipe 373 is disposed below the filter pipe 372. The walls of the manhole wall pipe 371 and the sedimentation pipe 373 are non-perforated and are solid pipe structures. The walls of the filter pipe 372 are perforated for reinjection. The diameter of the manhole wall pipe 371 and the diameter of the filter pipe 372 are, for example, equal. The manhole wall pipe 371, the filter pipe 372, and the sedimentation pipe 373 are connected by, for example, a pipe clamp threaded connection, a welded connection, a socket connection, or a bolted connection. In this embodiment, a backfill section 35 and a clay water-stop section 36 are provided on the outer side of the well wall pipe 371. The backfill section 35 is located above the clay water-stop section 36. This application does not limit the thickness of the backfill section 35 and the clay water-stop section 36. By providing the backfill section 35 and the clay water-stop section 36, leakage is prevented. The outer side of the filter pipe 372 is wrapped with a filter screen (not shown in the figure). The filter screen is, for example, a nylon mesh, to prevent filter material from entering the filter pipe 372. The depth range of the filter pipe 372 is, for example, 50m to 150m below the ground surface, so that the filter pipe 372 completely penetrates the unconfined aquifer and enters the confined aquifer. That is, the top of the filter pipe 372 is, for example, 50m below the ground surface, and the bottom of the filter pipe 372 is located in the confined aquifer. In this application, the confined aquifer is, for example, filled between the second water-proof layer 11 and the first water-proof layer 13.

[0039] Please see Figures 1 to 2As shown, in one embodiment of the present invention, an annular filter media layer 38 is also wrapped around the outside of the filter pipe 372 and the sedimentation pipe 373. The annular filter media layer 38 is, for example, wrapped around the outside of the filter screen, and the length ratio of the filter pipe 372 to the sedimentation pipe 373 is, for example, 10:1 to 15:1. The annular filter media layer 38 includes, for example, a first annular filter media layer 381, a second annular filter media layer 382, ​​and a third annular filter media layer 383 stacked sequentially. The first annular filter media layer 381 is disposed adjacent to the filter pipe 372. From the first annular filter media layer 381 to the third annular filter media layer 383, the particle size of the filter media decreases to improve the overall interception efficiency, reduce clogging, and slow down the increase of head loss. In this embodiment, the first annular filter layer 381 is, for example, at least one of gravel, crushed granite, porous ceramic aggregate or blast furnace slag with a particle size of 2mm to 5mm; the second annular filter layer 382 is, for example, at least one of modified zeolite, biochar, activated zeolite or mesoporous alumina with a particle size of 0.5mm to 1.2mm; and the third annular filter layer 383 is, for example, at least one of modified quartz sand, modified ceramsite, magnetite filter media or garnet with a particle size of 0.2mm to 0.4mm. The non-uniformity coefficient of each filter layer is controlled at 1.4 to 2.0 to avoid the pores being filled by fine particles and reducing the filtration efficiency. In this embodiment, the modified quartz sand, modified ceramsite, and modified zeolite are, for example, quartz sand, ceramsite, and zeolite with surface modifiers, respectively, obtained by deposition or in-situ hydrothermal synthesis. The modifiers are, for example, metal compounds or hydroxides of iron salts (such as FeCl3), aluminum salts (such as AlCl3), manganese salts (such as MnCl2), and magnesium salts (such as MgCl2).

[0040] Please see Figures 1 to 2 As shown, in one embodiment of the present invention, the total thickness of the annular filter media layer 38 is, for example, 100mm to 500mm, and the thickness ratio of the first annular filter media layer 381, the second annular filter media layer 382, ​​and the third annular filter media layer 383 is, for example, 1:2:1 to 2:3:1. In a specific embodiment of the present invention, the thickness of the first annular filter media layer 381 is, for example, 20mm to 150mm, the thickness of the second annular filter media layer 382 is, for example, 60mm to 250mm, and the thickness of the third annular filter media layer 383 is, for example, 20mm to 100mm. In other embodiments, the filter media thickness and particle size parameters can be adapted within a reasonable range according to the water quality of the source water. The bottom of the annular filter media layer 38 extends into the confined aquifer, and the top is higher than or level with the top of the filter pipe 372, or, for example, lower than the top plate of the confined aquifer, that is, the top is lower than the first water-proof layer 13, so as to replenish water to the confined aquifer. Through a multi-stage filtration structure design, non-point source pollutants are intercepted and water quality is purified simultaneously during the reinjection process, improving filtration efficiency and reducing the risk of clogging, thus avoiding secondary pollution of groundwater.

[0041] Please see Figures 1 to 3As shown, in one embodiment of the present invention, the anti-clogging unit includes a controller 50, which is, for example, a programmable logic controller (PLC), a distributed control system (DCS), or a programmable automation controller (PAC), among other intelligent control systems. In this embodiment, the controller 50 is, for example, a PLC, capable of online monitoring of the reinjection process and intelligently controlling the operation of the anti-clogging unit through the PLC. The controller 50 is installed in a ground facility near the multi-stage filtration reinjection unit 30. An electric control valve 51 is installed between the filter 33 and the filter layer 34. The electric control valve 51 is communicatively connected to the controller 50, and the controller 50 can control the opening and closing of the electric control valve 51. The anti-clogging unit includes an intermittent reinjection mode. Specifically, the electric control valve 51 is controlled to open and close according to a cycle of "reinjection Xh + rest Yh," where X:Y is, for example, 1:1 to 3:1, adjusted according to the water quality. In a specific embodiment of the present invention, reinjection is performed, for example, according to a cycle of "reinjection 12h + rest 4h." During the rest period, the blockages settle under gravity, and some of the microbial membranes attached to the filter layer surface naturally peel off, which can effectively restore the permeability of the multi-stage filtration recharge unit and reduce clogging.

[0042] Please see Figures 1 to 3 As shown, in one embodiment of the present invention, the first pressure detector 332 and the second pressure detector 334 in the filter 33 are respectively connected to the controller 50 for communication or by line to detect the pressure of the inlet and outlet water, provide early warning through the pressure difference change, and promptly remove the filter body 335 for manual cleaning to ensure the filtration effect.

[0043] Please see Figures 1 to 3As shown, in one embodiment of the present invention, the anti-clogging unit further includes a pumping pipe 41, which is disposed within the multi-stage filtration and reinjection unit 30. The pumping pipe 41, for example, penetrates the top cover 31, equipment layer 321, and support layer 322, extending into the well 37. That is, the diameter of the pumping pipe 41 is smaller than the diameter of the well wall pipe 371 and the filter pipe 372. A submersible pump 42 is disposed at the bottom of the pumping pipe 41, located within the filter pipe 372, and is communicatively connected to a controller 50, which can regulate the opening and closing of the submersible pump 42. A pressure sensor 43 and a flow sensor 44 are disposed on the well wall pipe 371. This application does not limit the relative positions of the pressure sensor 43 and the flow sensor 44. In this embodiment, the pressure sensor 43 is disposed, for example, near the wellhead of the well 37, and the flow sensor 44 is disposed below the pressure sensor 43 and simultaneously above the water level in the well 37. The pressure sensor 43 and the flow sensor 44 are communicatively connected or wired to the controller 50, respectively. In other embodiments, pressure sensor 43 and flow sensor 44 are, for example, installed within the water body of monitoring well 37. Pressure sensor 43 monitors changes in fluid pressure within well 37 to reflect issues such as reinjection resistance, blockages, or leaks. Flow sensor 44 measures the reinjection volume and flow rate in real time to calculate reinjection efficiency. A water level gauge or non-contact sensor (not shown) is also installed within well 37 to test the water level.

[0044] Please see Figure 1 and Figure 5As shown, in one embodiment of the present invention, the anti-clogging unit includes a backwashing mode for the pumping pipe. Specifically, when the controller 50 detects that the reinjection efficiency drops below 60% of the initial value and unreasonable water accumulation occurs in the well 37, the electric control valve 51 is closed, and the submersible pump 42 is turned on to pump water. The pumping flow rate is, for example, 1.5 to 2.0 times the reinjection flow rate, and the ratio of pumping to reinjection time is, for example, 1:6 to 1:8. The backwashing pressure of the pumping pipe 41 is controlled at 0.15 MPa to 0.25 MPa. The reverse water flow carries the blockage trapped in the well 37 and the annular filter layer 38 out of the well. The outlet of the pumping pipe 41 is connected to the surface water source 10 through a pipeline (not shown in the figure) to discharge the pumped water into the front end of the infiltration channel 20 to re-enter the reinjection process. This eliminates the need for external discharge and water waste, thereby solving the well clogging problem, significantly reducing operation and maintenance costs, and extending the system's service life. This application combines multi-stage filtration, intermittent reinjection, and backwashing via pumping pipes, achieving a blockage removal rate over 30% higher than traditional pipeline-based water reinjection methods. Backwash wastewater can be recycled back to the front end of the infiltration channel without external discharge. This extends the continuous operation period of the high-permeability well to over 5 years, reducing maintenance costs by over 40% compared to traditional technologies, significantly extending system lifespan and lowering maintenance costs. Therefore, the reinjection system provided by this application offers outstanding comprehensive benefits. While reducing maintenance costs and steadily raising regional groundwater levels, it serves as a stable backup water source for farmland irrigation, effectively mitigating the risk of crop yield reduction due to drought, thus providing ecological, economic, and social benefits. Furthermore, this reinjection system can be replicated and promoted in areas with similar terrain and water resources.

[0045] Please see Figures 1 to 5 As shown, in another embodiment of the present invention, the intermittent reinjection mode can be adjusted from a fixed cycle to a dynamic triggering mode for reinjection efficiency. The controller 50 collects real-time reinjection flow, pipeline pressure, and well water level data through pressure sensor 43 and flow sensor 44, etc. It obtains the reasonable pressure value and well water level corresponding to the current reinjection flow every 30 minutes. When the value is lower than 70% of the reasonable benchmark value for 2 consecutive hours, it is determined that the filter layer is showing a clogging trend. Then the controller 50 closes the electric control valve 51 and automatically stops reinjection to enter a rest period. After a rest period of 4 to 6 hours, the controller 50 opens the electric control valve 51 and automatically restarts reinjection. If the flow is still lower than 70% of the benchmark value after restarting, the controller 50 closes the electric control valve 51 and automatically triggers the submersible pump 42 to start and perform a backwashing procedure.

[0046] Please see Figure 1 and Figure 5As shown, in another embodiment of the present invention, a compressed air pipe (not shown in the figure) is connected to the bottom of the water filter pipe 372. In the backwashing mode of the water pump pipe, compressed air is introduced through the compressed air pipe to improve the backwashing efficiency. The backwashing pressure of the water pump pipe 41 is controlled at 0.15MPa~0.25MPa, and the air flushing pressure is controlled at 0.1MPa~0.2MPa, not exceeding 0.3MPa, to avoid excessive pressure damaging the annular filter media layer 38.

[0047] This invention also provides a groundwater recharge method based on a combination of surface water sources, infiltration channels, and wells. The aforementioned recharge system is installed near the adjacent surface water source where recharge is needed to recharge groundwater, thereby achieving efficient regulation and storage of regional water resources and sustainable groundwater replenishment. The recharge process is described below.

[0048] Please see Figures 1 to 5 As shown, in one embodiment of the present invention, during the recharge process, the water from the surface water source 10 enters the infiltration channel 20 under gravity. Part of the water replenishes shallow groundwater through natural infiltration, while the remaining water flows sequentially through the outlet of the infiltration channel 20 into the multi-stage filtration and recharge unit 30, including the filter 33, filter layer 34, well 37, and annular filter media layer 38. The water level in the well 37 rises, and the water enters the confined aquifer, recharging the groundwater. During the recharge process, based on the data transmitted by the recharge time or pressure detectors and sensors, the controller 50 activates either the intermittent recharge mode or the pumping pipe backwashing mode. The groundwater recharge system and method provided in this application achieve resource utilization of surface water sources, alleviating the spatial and temporal mismatch of water resources during flood season and drought season in plain areas. Furthermore, during the recharge process, non-point source pollutant interception and water purification are simultaneously achieved, preventing secondary groundwater pollution. This also alleviates well blockage problems, significantly extending the system's service life and reducing maintenance costs.

[0049] In summary, this invention proposes an artificial groundwater recharge system that enables natural infiltration during the water diversion process to replenish shallow groundwater, lengthening the actual flow path of water in the infiltration channel and significantly improving the shallow infiltration effect. Simultaneously, it rapidly replenishes deep aquifers through wells, balancing recharge rate and coverage. This system prevents groundwater pollution caused by recharge at the source, alleviates well blockage, significantly extends system lifespan, reduces operation and maintenance costs, and achieves efficient regional water resource regulation and sustainable groundwater recharge. Through multi-stage filtration and anti-clogging design, non-point source pollutant interception and water purification are achieved simultaneously during recharge, improving filtration efficiency and reducing the risk of blockage, thus preventing secondary groundwater pollution. By constructing a three-dimensional coordinated recharge system of surface water source-infiltration channel-well, a combined mode of shallow natural recharge through infiltration channels and deep precise recharge through wells is achieved, enabling coordinated recharge of shallow and deep groundwater and improving water resource utilization efficiency. This system can alleviate the spatial and temporal mismatch of water resources in plain areas, particularly during flood season and drought season. The reinjection system does not require large-scale civil engineering construction and can be quickly adapted and implemented based on existing river channels and well clusters. The construction cost per well is reduced, and its versatility and cost advantages are prominent.

[0050] The above description is merely a preferred embodiment of this application and an explanation of the technical principles used. Those skilled in the art should understand that the scope of the invention involved in this application is not limited to the technical solutions formed by a specific combination of the above-mentioned technical features, but should also cover other technical solutions formed by any combination of the above-mentioned technical features or their equivalent features without departing from the inventive concept. For example, technical solutions formed by replacing the above-mentioned features with technical features with similar functions disclosed in this application (but not limited to) each other.

[0051] Apart from the technical features described in the specification, the other technical features are known to those skilled in the art. To highlight the innovative features of this invention, the other technical features will not be described in detail here.

Claims

1. A groundwater artificial recharge system, comprising a surface water source, at least one infiltration channel, at least one multi-stage filtration and recharge unit, and at least one anti-clogging unit, characterized in that: The infiltration channel connects the surface water source and the multi-stage filtration and recharge unit, and the infiltration channel is arranged in a tortuous manner; the length of the infiltration channel is 2.5 to 4.0 times the straight-line distance between the surface water source and the multi-stage filtration and recharge unit; a grid structure is provided at the connection between the surface water source and the infiltration channel; Starting from the outlet end of the infiltration channel, the multi-stage filtration and reinjection unit includes at least a filter, a filter layer, a well, and an annular filter media layer. The well includes a well wall pipe and a filter pipe. The annular filter media layer wraps around the outside of the filter pipe. The filter layer and the annular filter media layer each have multiple layers. The top of the annular filter media layer is higher than or level with the top of the filter pipe, but lower than the top plate of the confined aquifer. The anti-clogging unit includes a controller, an electric control valve, and a water pumping pipe. The controller is installed on the ground, and the electric control valve and the water pumping pipe are respectively connected to the controller. The electric control valve is installed between the filter and the filter layer, and the water pumping pipe is installed in the well, with the outlet of the water pumping pipe connected to the surface water source. A pressure sensor and a flow sensor are installed on the well casing, and the pressure sensor and the flow sensor are respectively connected to the controller.

2. The groundwater artificial recharge system of claim 1, wherein, The infiltration channel is arranged in a curved or zigzag shape, the design water level of the infiltration channel is lower than the water level of the surface water source, the bottom of the infiltration channel is lower than the water level of the surface water source; and / or, the bottom of the infiltration channel is laid with a graded medium-coarse sand filter layer.

3. The artificial groundwater recharge system according to claim 1, characterized in that, The bottom of the infiltration channel is stepped, and the depth gradually increases along the direction of water flow.

4. The artificial groundwater recharge system according to claim 1, characterized in that, The spacing between adjacent multi-stage filtration and reinjection units is greater than or equal to twice the influence radius of the well.

5. The artificial groundwater recharge system according to claim 1, characterized in that, The multi-stage filtration and reinjection unit also includes a top cover, an equipment layer, and a support layer. The top cover engages with the wellhead of the well. The equipment layer is located at the bottom of the wellhead and on the support layer. The filter and filtration layer are located within the equipment layer.

6. The artificial groundwater recharge system according to claim 5, characterized in that, The filter includes an inlet end, a first pressure detector, a side opening, a second pressure detector, a filter body, and an outlet end. The inlet end and the outlet end are arranged opposite to each other at both ends of the filter. The inlet end is connected to the outlet end of the infiltration channel. The first pressure detector is located near the inlet end, and the second pressure detector is located near the outlet end. The filter body is taken out through the side opening. The first pressure detector and the second pressure detector are respectively connected to the controller.

7. The artificial groundwater recharge system according to claim 6, characterized in that, The filter layer includes an inlet, a first filter layer, a second filter layer, a third filter layer, and an outlet arranged in sequence. The inlet is connected to the outlet end of the filter, and the outlet extends through the equipment layer and the support layer into the manhole. The first filter layer is removed by opening the top cover.

8. The artificial groundwater recharge system according to claim 1, characterized in that, The well also includes a sedimentation pipe, the well wall pipe is located above the filter pipe, and the sedimentation pipe is located below the filter pipe; a submersible pump is installed at the bottom of the pumping pipe, the submersible pump is located inside the filter pipe, and the submersible pump is communicatively connected to the controller.

9. The artificial groundwater recharge system according to claim 8, characterized in that, The annular filter media layer includes a first annular filter media layer, a second annular filter media layer, and a third annular filter media layer stacked sequentially. The first annular filter media layer is disposed adjacent to the water filter pipe, and the particle size of the filter media decreases from the first annular filter media layer to the third annular filter media layer.

10. The artificial groundwater recharge system according to claim 8, characterized in that, The anti-clogging unit includes an intermittent backflow mode, and the controller regulates the opening and closing of the electric control valve; the anti-clogging unit also includes a backflushing mode for the pumping pipe, and the controller regulates the opening and closing of the submersible pump.

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