A method for controlling groundwater artificial recharge blockage

Abstract

The present invention is applicable to the technical field of groundwater treatment and provides a method for controlling artificial reinjection blockage of groundwater. In the present invention, the outer well pipe and the inner well pipe of the annular reinjection well are both above the ground, and an infiltration medium layer with water quality filtering and blockage control functions is filled between the inner well pipe and the outer well pipe. The reinjection water reaches the aquifer through the filter medium layer. The blockage location is controlled by controlling the particle size structure of the filter medium layer, reducing the blockage treatment time and economic costs, thereby achieving the purpose of continuous and efficient reinjection and filtering the water quality of the reinjection water; and in the case of blockage of filter medium particles and gas between the outer well pipe and the inner well pipe, the inner well is used for backwashing and exhaust; long-term operation is achieved by replacing the medium, the life of the reinjection system is extended, and reinjection is effectively promoted.

Description

Technical Field

[0001] The invention belongs to the technical field of groundwater treatment, and in particular relates to a groundwater artificial recharge blockage control method. Background Art

[0002] In recent years, groundwater extraction has increased, and groundwater over-exploitation has become serious, leading to a series of environmental problems such as aquifer depletion, land subsidence, seawater intrusion, wetland area reduction, and land desertification. Artificial groundwater recharge can effectively solve the above problems and is increasingly valued.

[0003] At present, artificial groundwater recharge at home and abroad mainly adopts two methods: surface infiltration recharge and well recharge. Well recharge is a method of injecting recharge water directly into the aquifer through drilling, large-diameter wells or tunnels. Among all recharge methods, this method is least restricted by terrain conditions, hydrogeological conditions, climate change, etc., and occupies a small area. It can concentrate the recharge to the designated aquifer and waste less water. However, it has high requirements for the quality of recharge water. It is easy to get clogged in the well and difficult to control, resulting in a reduction in the recharge rate or even the scrapping of the well pipe. The problem of clogging is always a limiting factor in the well recharge process. How to control the clogging, increase the infiltration rate, and effectively increase the amount of available groundwater resources is an urgent problem to be solved. Therefore, it is very important to develop a method for controlling clogging during groundwater well recharge. To this end, we propose a method for controlling clogging of artificial groundwater recharge. Summary of the Invention

[0004] The purpose of the present invention is to provide a method for controlling the blockage of artificial groundwater recharge, aiming to solve the problem of blockage of infiltration medium during well irrigation.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] A method for controlling groundwater artificial recharge blockage comprises the following steps:

[0007] Step S1: Establish a recharge well

[0008] Step S11: The outer well pipe and the inner well pipe of the annular recharge well are both 1.5 m above the ground. The depth of the annular recharge well is 18 m, reaching the depth of the infiltration layer. The outer well pipe located above the ground is connected to the lower well pipe by a flange. The lower well pipe is provided with a water filter with a bridge-shaped hole at the position of the aquifer.

[0009] Step S12: The inner well is backwashed and vented. The upper end of the inner well pipe is open and the bottom end is closed. An exhaust hole is drilled in the lower part of the inner well pipe. The hole position is consistent with the water filter. A filter screen is wrapped around the hole position at the lower part of the inner well pipe.

[0010] Step S13: Filling an infiltration medium layer with water filtration and clogging control functions between the inner well pipe and the outer well pipe, so that the recharge water flows through the inner well pipe and the outer well pipe, and reaches the aquifer through the filter medium layer; the particle size structure of the filter medium layer of the annular recharge well is fine at the top and coarse at the bottom, and the clogging is controlled to the surface layer of the infiltration medium;

[0011] Step S2: Filling the outer well with a medium that has a filtering and cementing function at a size of 2-5 times or more of the median particle size of the aquifer;

[0012] Step S3: Cement or clay balls are used to seal the upper part between the outer well and the hole wall of the shallow recharge well to stop water, and an exhaust pipe is inserted into the cement or clay balls. A hole is opened at the end of the exhaust pipe to be placed in the filter material layer to remove the gas trapped in the filter medium during the recharge process, eliminate or alleviate the possible gas blockage in the filter material area between the inner well pipe and the outer well pipe of the annular recharge well, and the exhaust pipe monitors the recharge water level.

[0013] Furthermore, the outer well pipe is a PPR or PVC-U pipe.

[0014] Furthermore, the porosity of the water filter is 25%, and the water filter is covered with a nylon mesh.

[0015] Furthermore, the inner well pipe is a PE pipe.

[0016] Furthermore, in step S12, the exhaust holes are circular holes, the exhaust holes are arranged as triangle vertices, the diameter of the exhaust holes is 4-5 mm, and the hole spacing is twice the hole diameter.

[0017] Furthermore, in step S12, the filter mesh is a plastic mesh.

[0018] Furthermore, in step 3, the height of the cement or clay ball is set to be at least 3 meters from the ground; the bottom of the exhaust pipe exceeds the cement or clay ball enclosed area and enters the filter material layer by at least 2 meters.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] This method for controlling blockage in artificial groundwater recharge can effectively control the blockage position by controlling the particle size structure of the filter medium layer, facilitate medium replacement, reduce blockage treatment time and economic costs, achieve the purpose of continuous and efficient recharge and filter the water quality of the recharged water; utilize the inner well for backwashing and exhaust; achieve long-term operation by replacing the medium, extend the life of the recharge system, and effectively promote recharge. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a structural schematic diagram of the present invention.

[0022] Figure 2 This is a schematic diagram of the existing recharge well structure.

[0023] In the figure: 1-hole wall, 2-outer well, 3-inner well, 4-exhaust pipe, 5-fine particle filter medium, 6-coarse sand, 7-coarse particle filter medium, 8-coarse particle filter medium, 9-clay ball, 10-filter. Implementation Method

[0024] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0025] The specific implementation of the present invention is described in detail below with reference to specific embodiments.

[0026] like Figure 1 As shown, a method for controlling groundwater artificial recharge blockage according to an embodiment of the present invention includes the following steps:

[0027] Step S1: Establish a recharge well

[0028] Step S11: The outer well 2 and inner well 3 of the annular recharge well are both 1.5 m above the ground. The depth of the annular recharge well is 18 m, reaching the depth of the infiltration layer. The outer well 2, located above the ground, is connected to the lower well pipe by a flange. The lower well pipe is provided with a water filter 10 with a bridge-shaped hole at the aquifer position.

[0029] Step S12: Backwash and exhaust are performed on the inner well 3. The upper end of the inner well 3 well pipe is open and the lower end is closed. An exhaust hole is drilled in the lower part of the inner well 3 well pipe. The hole position is consistent with the water filter 10. A filter screen is wrapped around the hole position at the lower part of the inner well 3 well pipe.

[0030] Step S13: An infiltration medium layer having water filtration and clogging control functions is installed between the inner well 3 well pipe and the outer well 2 well pipe. The recharge water flows through the space between the inner well 3 well pipe and the outer well 2 well pipe, through the filter medium layer, and reaches the aquifer. The particle size structure of the filter medium layer of the annular recharge well is fine at the top and coarse at the bottom, and the clogging is controlled to the surface layer of the infiltration medium.

[0031] Step S2: Fill the area around the outer well 2 with a medium that has a filtering and cementing function, with a particle size of 2-5 times or more of the median particle size of the aquifer;

[0032] Step S3: Cement or clay balls 9 are used to seal the upper portion between the outer well 2 and the hole wall 1 of the shallow recharge well to stop water flow, and an exhaust pipe 4 is inserted into the cement or clay balls 9. A hole is opened at the end of the exhaust pipe 4 to be placed in the filter material layer to remove gas trapped in the filter medium during the recharge process, eliminate or alleviate possible gas blockage in the filter material area between the well pipe of the inner well 3 and the well pipe of the outer well 2 of the annular recharge well. At the same time, the exhaust pipe 4 monitors the recharge water level.

[0033] In an embodiment of the present invention, preferably, in step S11, the diameter of the annular recharge well is determined comprehensively based on the designed recharge volume and the drilling process; in step S13, the recharge water undergoes an interface migration after being filtered by the filter material, thereby greatly reducing the risk of blockage during the seepage process inside the well pipe; the particle size structure of the filter medium layer of the annular recharge well is filled with a structure of fine at the top and coarse at the bottom, so that the upper permeability coefficient is smaller than the lower permeability coefficient, and the blockage that is originally prone to occur inside the well pipe is controlled to the surface layer of the infiltration medium, so that the recharge rate can be restored to the level before the blockage by replacing the filter medium layer.

[0034] like Figure 1 As shown, as a preferred embodiment of the present invention, the outer well 2 well pipe is a PPR or PVC-U pipe.

[0035] In the embodiment of the present invention, preferably, the outer pipe of the outer well 2 located above the ground is connected to the lower well pipe by a flange and is detachable.

[0036] like Figure 1 As shown, as a preferred embodiment of the present invention, the porosity of the water filter 10 is 25%, and the water filter 10 is covered with a nylon mesh.

[0037] like Figure 1 As shown, as a preferred embodiment of the present invention, the inner well 3 well pipe is a PE pipe.

[0038] In the embodiment of the present invention, preferably, the outer side of the well pipe of the inner well 3 is filled with a coarser particle filter medium layer 7, and the coarser particle filter medium layer 7 is filled with a fine particle filter medium layer 5, and the particle diameter of the fine particle filter medium layer 5 is smaller than the particle diameter of the coarser particle filter medium layer 7.

[0039] like Figure 1 As shown, as a preferred embodiment of the present invention, in step S12, the exhaust holes are circular holes, the exhaust holes are arranged as triangle vertices, the diameter of the exhaust holes is 4-5 mm, and the hole spacing is twice the hole diameter.

[0040] like Figure 1 As shown, as a preferred embodiment of the present invention, in step S12, the filter net is a plastic net.

[0041] like Figure 1As shown, as a preferred embodiment of the present invention, in step 3, the height of the cement or clay ball 9 is set to be at least 3m from the ground; the bottom of the exhaust pipe 4 exceeds the closed area of the cement or clay ball 9 and enters the filter material layer by at least 2m.

[0042] In the embodiment of the present invention, preferably, the filter material layer here is a coarse particle filter medium layer 8, and the particle diameter of the coarse particle filter medium layer 7 is smaller than the particle diameter of the coarse particle filter medium layer 8; coarse sand 6 is filled between the coarse particle filter medium layer 8 and the cement or clay balls 9.

[0043] The method for controlling blockage of artificial groundwater recharge is as follows: an inner well 3 and an outer well 2 are both arranged above the ground, and an infiltration medium layer with water quality filtering and blockage control functions is filled between the inner well 3 and the outer well 2. Recharge water reaches the aquifer through the filter medium layer, thereby reducing the risk of blockage during seepage inside the well pipe; the particle size structure of the filter medium layer is controlled to control the location of blockage, so that blockage occurs mainly at the upper position of the infiltration zone, reducing blockage treatment time and economic costs, thereby achieving the purpose of continuous and efficient recharge and filtering the water quality of the recharge water; and in case of blockage of filter medium particles and gas between the inner well 3 and the outer well 2, the inner well 3 is used for backwashing and exhaust.

[0044] The above are only preferred embodiments of the present invention. It should be pointed out that for those skilled in the art, several variations and improvements can be made without departing from the concept of the present invention. These should also be regarded as the scope of protection of the present invention. These will not affect the effect of the implementation of the present invention and the practicality of the patent.

Claims

1. A method for controlling groundwater artificial recharge blockage, characterized in that: The following steps are involved: Step S1, establishing a recharge well; Step S11: The outer well pipe and the inner well pipe of the annular recharge well are both 1.5 m above the ground. The depth of the annular recharge well is 18 m, reaching the depth of the infiltration layer. The outer well pipe located above the ground is connected to the lower well pipe by a flange. The lower well pipe is provided with a water filter with a bridge-shaped hole at the position of the aquifer. Step S12: The inner well is backwashed and vented. The upper end of the inner well pipe is open and the bottom end is closed. An exhaust hole is drilled in the lower part of the inner well pipe. The hole position is consistent with the water filter. A filter screen is wrapped around the hole position at the lower part of the inner well pipe. Step S13: Filling an infiltration medium layer with water filtration and clogging control functions between the inner well pipe and the outer well pipe, so that the recharge water flows through the inner well pipe and the outer well pipe, and reaches the aquifer through the filter medium layer; the particle size structure of the filter medium layer of the annular recharge well is fine at the top and coarse at the bottom, and the clogging is controlled to the surface layer of the infiltration medium; Step S2: Filling the outer well with a medium having a filtering and cementing function at a size of 5 times the median particle size of the aquifer; Step S3: Cement or clay balls are used to seal the upper part between the outer well and the hole wall of the shallow recharge well to stop water, and an exhaust pipe is inserted into the cement or clay balls. A hole is opened at the end of the exhaust pipe to be placed in the filter material layer to remove the gas trapped in the filter medium during the recharge process, eliminate or alleviate the possible gas blockage in the filter material area between the inner well pipe and the outer well pipe of the annular recharge well, and the exhaust pipe monitors the recharge water level.

2. The method for controlling groundwater artificial recharge blockage according to claim 1, characterized in that: The outer well pipe is a PPR or PVC-U pipe.

3. The method for controlling groundwater artificial recharge blockage according to claim 2, characterized in that: The porosity of the water filter is 25%, and the water filter is covered with a nylon mesh.

4. The method for controlling groundwater artificial recharge blockage according to claim 3, characterized in that: The inner well pipe is a PE pipe.

5. The method for controlling groundwater artificial recharge blockage according to claim 1, characterized in that: In step S12, the exhaust holes are circular holes, the exhaust holes are arranged as triangle vertices, the diameter of the exhaust holes is 4-5 mm, and the hole spacing is twice the hole diameter.

6. The method for controlling groundwater artificial recharge blockage according to claim 1, characterized in that: In step S12, the filter net is a plastic net.

7. The method for controlling groundwater artificial recharge blockage according to any one of claims 1 to 6, characterized in that: In step 3, the height of the cement or clay ball is set to be at least 3 meters from the ground; the bottom of the exhaust pipe exceeds the cement or clay ball enclosed area and enters the filter material layer by at least 2 meters.

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