Mine underground water nanofiltration treatment device

Abstract

The invention relates to the field of coal mine production, in particular to a mine underground water nanofiltration treatment device which comprises a pre-filtering system, a filtering system and a water producing system. The pre-filtering system comprises a raw water pump and a filter, the water inlet end of the raw water pump is communicated with mine water, and the water outlet end of the raw water pump is communicated with the water inlet end of the filter through a first connecting pipe; the filtering system comprises a circulating pump, a switching valve group and a nanofiltration membrane assembly, the water inlet end of the circulating pump is communicated with the water outlet end of the filter through a second connecting pipe, the switching valve group is communicated with the water outlet end of the circulating pump through a fourth connecting pipe, and the switching valve group is communicated with the nanofiltration membrane assembly through a fifth connecting pipe; the water production system comprises a water production pipe and a water production tank, and the water production pipe is used for communicating the nanofiltration membrane assembly with the water production tank. The device has the effects of reducing the floor area on the ground and improving the treatment efficiency.

Description

Technical Field

[0001] The present application relates to the field of coal mine production, and in particular to a nanofiltration treatment device for underground mine water. Background Art

[0002] During coal mining, a large amount of mine water is produced. This water contains a large amount of suspended solids, making it extremely turbid. It also contains a lot of oily components on its surface and a large amount of various acidic ions and ferrous ions inside. Even processes with low water quality requirements, such as coal seam injection, cannot use mine water directly, let alone processes with higher water quality requirements. Therefore, it is urgent to treat mine water so that it can be used in production.

[0003] For mine water, if it is directly discharged to the ground without treatment, it will not only cause great pollution to the environment, but also waste precious water resources. Therefore, there is an urgent need for a water treatment device to treat mine water.

[0004] In response to the above situation, many devices for mine water treatment have been designed in the existing technology. The current process of purifying mine water includes underground water tank-lifting pump-primary sedimentation and adjustment tank-dosing coagulation and clarification tank-filtration tank-standard discharge. The purification process is cumbersome, and the mine water in the underground water tank needs to be pressurized by the lifting pump and then flow into the sedimentation and adjustment device on the ground, which occupies a large area and has low treatment efficiency. Summary of the Invention

[0005] In order to reduce the ground floor space and improve the treatment efficiency, the present application provides a nanofiltration treatment device for underground mine water.

[0006] The present application provides a nanofiltration treatment device for underground mine water using the following technical solutions: A nanofiltration treatment device for underground mine water, comprising a pre-filtration system, a filtration system and a water production system; The pre-filtration system includes a raw water pump and a filter, wherein the water inlet of the raw water pump is connected to the mine water, and the water outlet of the raw water pump is connected to the water inlet of the filter through a first connecting pipe; The filtration system includes a circulation pump, a switching valve group and a nanofiltration membrane assembly, wherein the water inlet end of the circulation pump is connected to the water outlet end of the filter through a second connecting pipe, the switching valve group is connected to the water outlet end of the circulation pump through a fourth connecting pipe, and the switching valve group is connected to the nanofiltration membrane assembly through a fifth connecting pipe; The water production system includes a water production pipe and a water production tank, and the water production pipe is used to connect the nanofiltration membrane assembly and the water production tank.

[0007] Optionally, a third connecting pipe is installed in parallel between the first connecting pipe and the second connecting pipe.

[0008] Optionally, the nanofiltration membrane assembly includes multiple nanofiltration membranes, and the multiple nanofiltration membranes are connected in parallel.

[0009] Optionally, there are two water inlet ends on the nanofiltration membrane, and the switching valve group includes two valve group pipelines, the two valve group pipelines are arranged in parallel, each valve group pipeline is connected to the circulation pump through a fifth connecting pipe, each valve group pipeline includes an eighth valve and a ninth valve, and a fifth connecting pipe is installed between the eighth valve and the ninth valve on each valve group pipeline, and the two fifth connecting pipes are respectively connected to the two water inlet ends on the nanofiltration membrane.

[0010] Optionally, a circulation pipe connected to the water inlet end of the circulation pump is installed on the switching valve group.

[0011] Optionally, a drain pipe is installed on the circulation pipe.

[0012] Optionally, two drain pipes are provided, and the pipe opening diameters of the two drain pipes are different.

[0013] Optionally, a pipeline mixer is installed on the second connecting pipe, a scale inhibitor tank and an acid drug tank are installed on the pipeline mixer, a backwash pump is installed on the produced water tank, and the backwash pump is connected to the second connecting pipe through a reflux pipe.

[0014] Optionally, the backwash pump is connected to the nanofiltration membrane assembly through a backwash pipe.

[0015] In summary, this application includes at least one of the following beneficial technical effects: The mine water flows into the filter after being pressurized by the raw water pump. The filter performs preliminary filtration on the mine water. The filtered mine water flows into the circulation pump. After being pressurized by the circulation pump, it flows into the nanofiltration membrane assembly through the switching valve group. The nanofiltration membrane in the nanofiltration membrane assembly deeply filters the mine water. The water filtered by the nanofiltration membrane is divided into concentrated water and produced water. The produced water flows into the production water tank through the production water pipe. Part of the concentrated water flows into the circulation pump through the circulation pipe, and flows into the nanofiltration membrane assembly again through the circulation pump. The other part is discharged through the drain pipe. The device of this application purifies the mine water through the pre-filtration system, the filtration system and the water production system in sequence, which can shorten the water purification process. At the same time, the device of this application is located under the mine, occupies a small area and has high processing efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a first structural schematic diagram of a nanofiltration treatment device for underground mine water in an embodiment of the present application.

[0017] Figure 2 This is a second structural schematic diagram of a nanofiltration treatment device for underground mine water in an embodiment of the present application.

[0018] Figure 3 This is a flow chart of a nanofiltration treatment device for underground mine water according to an embodiment of the present application.

[0019] Figure 4 It is a flow chart of a pre-filtration system of a nanofiltration treatment device for underground mine water according to an embodiment of the present application.

[0020] Figure 5 This is a schematic flow chart of the operation of the eighth valve of a nanofiltration treatment device for underground mine water in an embodiment of the present application.

[0021] Figure 6 This is a schematic flow chart of the operation of the ninth valve of a nanofiltration treatment device for underground mine water in an embodiment of the present application.

[0022] Figure 7 This is a flow chart of a water production system of a nanofiltration treatment device for underground mine water according to an embodiment of the present application.

[0023] Figure 8 This is a schematic flow chart of a water-washed nanofiltration membrane of a mine underground water nanofiltration treatment device according to an embodiment of the present application.

[0024] Figure 9 This is a schematic flow chart of a drug-washed nanofiltration membrane in a mine underground water nanofiltration treatment device according to an embodiment of the present application.

[0025] Explanation of reference numerals: 1. Pre-filtration system; 11. Raw water pump; 111. Water pipe; 112. First valve; 12. Filter; 121. First connecting pipe; 1211. Second valve; 122. Second connecting pipe; 1221. Third valve; 123. Third connecting pipe; 1231. Fourth valve; 2. Filtration system; 21. Circulation pump; 211. Fifth valve; 212. Fourth connecting pipe; 22. Switching valve group; 221. Eighth valve; 222. Ninth valve; 223. Fifth connecting pipe; 2231. Twelfth valve; 23. Nanofiltration membrane assembly; 231. Nanofiltration membrane assembly Filter membrane; 3. Water production system; 31. Water production pipe; 311. Thirteenth valve; 312. Fourteenth valve; 32. Water production tank; 321. Water supply pipe; 4. Pipe mixer; 41. Scale inhibitor tank; 42. Acid drug tank; 43. First drug pipe; 44. Second drug pipe; 45. Sixth valve; 46. Seventh valve; 47. Diaphragm metering pump; 5. Circulation pipe; 51. Tenth valve; 6. Drain pipe; 61. Eleventh valve; 7. Backwash pump; 71. Sixth connecting pipe; 72. Fifteenth valve; 8. Reflux pipe; 81. Sixteenth valve; 9. Backwash pipe; 91. Seventeenth valve. DETAILED DESCRIPTION

[0026] The following is combined with Figure 1-9 This application is described in further detail.

[0027] The embodiment of the present application discloses a nanofiltration treatment device for underground mine water.

[0028] Reference Figure 1 、 Figure 2 and Figure 3 A nanofiltration treatment device for underground mine water includes a pre-filtration system 1, a filtration system 2 and a water production system 3, and the pre-filtration system 1, the filtration system 2 and the water production system 3 are all located underground.

[0029] Reference Figure 1 、 Figure 2 、 Figure 3 and Figure 4 The pre-filtration system 1 includes a raw water pump 11 and a filter 12. The raw water pump 11's inlet and outlet are both equipped with first valves 112 via rubber joints. The raw water pump 11's inlet is connected to the mine water via a water pipe 111. The filter 12's inlet is connected to the raw water pump 11's outlet via a first connecting pipe 121, which is equipped with a second valve 1211. The filter 12's outlet is connected to the circulating pump 21's inlet via a second connecting pipe 122, which is equipped with a third valve 1221. It should be noted that the raw water pump 11 is a centrifugal pump.

[0030] The mine water is pressurized by the raw water pump 11 and then enters the filter 12 . The filter 12 performs preliminary filtration on the mine water, filtering out coarse impurities such as mud, sand, and rust in the mine water. The filtered water flows into the circulation pump 21 through the second connecting pipe 122 .

[0031] It should be noted that the filter 12 is a brush filter 12, which is used to filter mine water, filter out coarse impurities such as mud, rust, etc. in the water source, and then enter the circulation pump. The filtration accuracy range of the filter 12 is 20um~150um. The larger the filtration accuracy range, the lower the filtration accuracy, and vice versa. A filtration accuracy that is too high or too low will affect the device. A high filtration accuracy will cause the pre-filtration system 1 to be blocked, and a low filtration accuracy will cause the filtration system 2 to be blocked. In the embodiment of the present application, the filtration accuracy range of the filter 12 is 30um~75um.

[0032] When filter 12 needs to be cleaned, a third connecting pipe 123 is installed in parallel between first connecting pipe 121 and second connecting pipe 122 to ensure proper operation of the device. One end of third connecting pipe 123 is connected to the outlet of raw water pump 11, and the other end is connected to the inlet of circulation pump 21. A fourth valve 1231 is installed on third connecting pipe 123. By closing second valve 1211 and third valve 1221 and opening fourth valve 1231, the mine water, after being pressurized by raw water pump 11, enters circulation pump 21 directly.

[0033] Reference Figure 1、 Figure 2 、 Figure 3 、 Figure 5 and Figure 6 The filtration system 2 includes a circulation pump 21, a switching valve group 22, and a nanofiltration membrane assembly 23. The water inlet and outlet of the circulation pump 21 are both installed with a fifth valve 211 through a rubber flexible joint. The water inlet of the circulation pump 21 is connected to the water outlet of the filter 12 through the second connecting pipe 122; the switching valve group 22 is connected to the water outlet of the circulation pump 21 through the fourth connecting pipe 212, and the switching valve group 22 is connected to the nanofiltration membrane assembly 23 through the fifth connecting pipe 223. It should be noted that the nanofiltration membrane assembly 23 includes two groups of nanofiltration membrane groups, and one nanofiltration membrane group is composed of multiple nanofiltration membranes 231 connected in parallel.

[0034] A nanofiltration membrane 231 is provided with two water inlets and a water production end. Concentrated water formed within the nanofiltration membrane 231 flows out of one of the water inlets, while produced water formed within the nanofiltration membrane 231 flows out of the water production end through internal pipes within the nanofiltration membrane 231. The switching valve group 22 includes two valve group pipes, which are arranged in parallel. One end of each valve group pipe is connected to the water outlet of the circulation pump 21 via a fourth connecting pipe 212, and the other end is installed with a circulation pipe 5, which is connected to the water inlet of the circulation pump 21. Each valve group pipe includes an eighth valve 221 and a ninth valve 222. A fifth connecting pipe 223 is installed between the eighth valve 221 and the ninth valve 222 on each valve group pipe. Each fifth connecting pipe 223 is connected to the two water inlets of the nanofiltration membrane 231. A twelfth valve 2231 is installed on the fifth connecting pipe 223. It should be noted that the eighth valve 221 and the ninth valve 222 on the two-way valve group pipeline are placed diagonally, and the eighth valve 221 and the ninth valve 222 are opened and closed at intervals. It should be noted that a drain pipe 6 is installed on the circulation pipe 5.

[0035] like Figure 5 As shown, that is, when the two eighth valves 221 are opened, the two ninth valves 222 are closed, and the raw water flows into the upper water inlet end of the nanofiltration membrane 231 through the eighth valve 221 in the upper left corner. The raw water is filtered by the nanofiltration membrane 231 to form concentrated water, which is discharged from the lower water inlet end of the nanofiltration membrane 231. After the concentrated water passes through the eighth valve 221 in the lower right corner, part of the concentrated water flows into the floor drain through the drain pipe 6, and the other part of the concentrated water flows back to the circulation pump 21 through the circulation pipe 5, and then flows into the nanofiltration membrane 231 through the switching valve group 22 through the circulation pump 21.

[0036] like Figure 6As shown, when the two ninth valves 222 are opened, the two eighth valves 221 are closed, and the raw water flows into the lower water inlet end of the nanofiltration membrane 231 through the ninth valve 222 in the lower left corner. The raw water is filtered by the nanofiltration membrane 231 to form concentrated water, which is discharged from the upper water inlet end of the nanofiltration membrane 231. After the concentrated water passes through the ninth valve 222 in the upper right corner, part of the concentrated water flows into the floor drain through the drain pipe 6, and the other part of the concentrated water flows back to the circulation pump 21 through the circulation pipe 5, and then flows into the nanofiltration membrane 231 through the switching valve group 22 through the circulation pump 21.

[0037] It should be noted that the circulation pump 21 is used to provide appropriate water pressure and water flow to the nanofiltration membrane 231. The water pressure range is 2 bar to 8 bar, and the water flow range is 2 to 8 times the water flow at the water production end of the nanofiltration membrane 231. That is, if the water flow at the water production end of the nanofiltration membrane 231 is 1 m³ / h, the water flow of the water pump is 2 to 8 m³ / h. In this application, the water pressure is 3 bar to 6 bar, and the water flow is 3 to 6 times the water flow at the water production end of the nanofiltration membrane 231.

[0038] It is also important to note that the water flow rate in the circulation pipe 5 is 2 to 8 times the water flow rate at the water production end of the nanofiltration membrane 231 , thereby increasing the flow rate in the nanofiltration membrane 231 .

[0039] The water pressurized by the circulation pump 21 enters the nanofiltration membrane 231 through the switching valve group 22. The water flows into the nanofiltration membrane 231 from one water inlet end and flows out from the other water inlet end. The outflow rate is 5% to 50% of the inflow rate. In this application, the outflow rate is between 10% and 30% of the inflow rate.

[0040] In order to control the on-off of the circulation pipe 5 , a tenth valve 51 is installed on the circulation pipe 5 ; in order to control the on-off of the drainage pipe 6 , an eleventh valve 61 is installed on the drainage pipe 6 .

[0041] The eighth valve 221 and the ninth valve 222 are opened and closed at intervals to achieve cross-current flow of water in the nanofiltration membrane 231, which can extend the service life of the nanofiltration membrane 231, thereby extending the service life of the nanofiltration membrane 231 and reducing operation and maintenance costs.

[0042] When the concentrated water in the nanofiltration membrane 231 flows out through the upper water inlet end or the lower water inlet end, part of the concentrated water is discharged through the drain pipe 6. The water flow rate range of the concentrated water in the drain pipe 6 is 5% to 50% of the water inlet flow of the nanofiltration membrane 231. A low water flow rate of the concentrated water in the drain pipe 6 will cause the incoming water to not be completely filtered, thereby reducing the water quality of the produced water. A high water flow rate of the concentrated water in the drain pipe 6 will improve the water quality of the produced water, but it will waste water resources. Therefore, the water flow rate range of the concentrated water in the drain pipe 6 is between 10% and 30%, which ensures the water quality of the produced water and saves water resources at the same time.

[0043] Reference Figure 1 、 Figure 2 、 Figure 3 and Figure 7 The water production system 3 includes a water production pipe 31 and a water production tank 32. One end of the water production pipe 31 is connected to the water production end of the nanofiltration membrane 231, and the other end is connected to the water production tank 32. The water produced within the nanofiltration membrane assembly 23 flows through the water production pipe 31 into the water production tank 32, which is used to store the produced water. The water production tank 32 is equipped with a water supply pipe 321 for connecting to the target user. It is important to note that a thirteenth valve 311 is installed on the water production pipe 31 of each nanofiltration membrane 231 group, and a fourteenth valve 312 is installed on the water production pipe 31 near the water production tank 32.

[0044] It should be noted that the water tank 32 is equipped with a respirator, an ultraviolet sterilizer (UV) and a liquid level controller (LY). The respirator is used to maintain the pressure balance between the inside and outside of the water tank 32, the ultraviolet sterilizer is used to perform ultraviolet disinfection on the produced water in the water tank 32, and the liquid level meter is used to monitor the liquid level of the produced water in the water tank 32.

[0045] Reference Figure 1 、 Figure 2 、 Figure 8 and Figure 9 The backwash pump 7 is installed on the production water tank 32 via a sixth connecting pipe 71. A fifteenth valve 72 is installed at both the water inlet and outlet of the backwash pump 7 via rubber flexible joints. The production water tank 32 is connected to the water inlet of the backwash pump 7 via the sixth connecting pipe 71. The water outlet of the backwash pump 7 is connected to the water inlet of the circulation pump 21 via a return pipe 8, on which a sixteenth valve 81 is installed. The water outlet of the backwash pump 7 is also connected to the water production end of the nanofiltration membrane 231 via a backwash pipe 9, on which a seventeenth valve 91 is installed.

[0046] like Figure 8 As shown, when the nanofiltration membrane assembly 23 needs to be washed with water, the fifth valve 211, the fourteenth valve 312, the sixteenth valve 81 and the tenth valve 51 are closed, and the fifteenth valve 72, the backwash pump 7, the seventeenth valve 91, the thirteenth valve 311, the twelfth valve 2231, the eighth valve 221 and the eleventh valve 61 are opened. The produced water in the produced water tank 32 flows into the nanofiltration membrane 231 after being pressurized by the backwash pump 7, and the nanofiltration membrane 231 is cleaned. After cleaning, the sewage is discharged through the drain pipe 6. It should be noted that there are two drain pipes 6, and the pipe openings of the two drain pipes 6 have different diameters. The drain pipe 6 with a larger pipe opening diameter is used to discharge sewage, and the drain pipe 6 with a smaller pipe opening diameter is used to discharge concentrated water.

[0047] A pipeline mixer 4 is mounted on the second connecting pipe 122. A scale inhibitor tank 41 and an acidic drug tank 42 are mounted on the pipeline mixer 4. The pipeline mixer 4 is connected to the scale inhibitor tank 41 via a first drug pipe 43. The scale inhibitor tank 41 is used to store the scale inhibitor. The pipeline mixer 4 is connected to the acidic drug tank 42 via a second drug pipe 44. The acidic drug tank 42 is used to store the acidic drug. In this embodiment of the present application, the acidic drug is food-grade citric acid.

[0048] A sixth valve 45 , a seventh valve 46 and a diaphragm metering pump 47 are installed on both the first drug tube 43 and the second drug tube 44 . The diaphragm metering pump 47 is located between the sixth valve 45 and the seventh valve 46 .

[0049] like Figure 9 As shown, when the nanofiltration membrane assembly 23 needs chemical washing, the fourteenth valve 312, the seventeenth valve 91, the thirteenth valve 311, the third valve 1221, the fourth valve 1231, the tenth valve 51 and the ninth valve 222 are closed, the fifteenth valve 72, the backwash pump 7, the sixteenth valve 81, the sixth valve 45, the seventh valve 46, the fifth valve 211, the eighth valve 221, the twelfth valve 2231 and the eleventh valve 61 are opened, and the scale inhibitor in the scale inhibitor tank 41 flows through the first drug pipe 43. The acidic drug in the acidic drug tank 42 flows into the second connecting pipe 122 through the second drug pipe 44. The produced water in the produced water tank 32 flows into the second connecting pipe 122 through the return pipe 8, where it is mixed with the scale inhibitor and the acidic drug to produce mixed water. The mixed water is pressurized by the circulation pump 21 and flows into the nanofiltration membrane assembly 23 through the switching valve group 22. The mixed water cleans the nanofiltration membrane 231 in the nanofiltration membrane assembly 23. After cleaning, the wastewater is discharged through the drain pipe 6. It should be noted that the function of the scale inhibitor is to prevent scaling and clogging inside the nanofiltration membrane 231. The acidic drug is added at a regular interval. The regular interval is set according to actual conditions and can be added once a month, once a quarter, or once every six months.

[0050] Reference Figures 1 to 9 It should be noted that the eighth valve 221 and the ninth valve 222 are electromagnetic valves, and the first valve 112 to the seventh valve 46 and the tenth valve 51 to the seventeenth valve 91 can be either electromagnetic valves or manual valves.

[0051] It should be noted that a pressure gauge (PI) is installed on the second connecting pipe 122 and the water production pipe 31, a digital pressure transmitter (PIT) is installed on the second connecting pipe 122, the fourth connecting pipe 212 and the water production pipe 31, a digital flow meter (FIT) is installed on the second connecting pipe 122, the fourth connecting pipe 212, the water production pipe 31 and the drain pipe 6, and a digital conductivity meter (CIT) and an online turbidity meter (NTU) are also installed on the second connecting pipe 122 and the water production pipe 31.

[0052] The implementation principle of the nanofiltration treatment device for underground mine water in the embodiment of the present application is as follows: the mine water flows into the filter 12 after being pressurized by the raw water pump 11, and the filter 12 performs preliminary filtration on the mine water. The filtered mine water flows into the circulation pump 21, and after being pressurized by the circulation pump 21, it flows into the nanofiltration membrane assembly 23 through the switching valve group 22. The nanofiltration membrane 231 in the nanofiltration membrane assembly 23 performs deep filtration on the mine water. The water filtered by the nanofiltration membrane 231 is divided into concentrated water and produced water, with produced water accounting for 70% to 90% and concentrated water accounting for 10% to 30%. The produced water flows into the produced water tank 32 through the produced water pipe 31, and part of the concentrated water flows into the circulation pump 21 through the circulation pipe 5, and flows into the nanofiltration membrane assembly 23 again through the circulation pump 21, and the other part is discharged through the drain pipe 6. The device of the present application purifies the mine water through the pre-filtration system 1, the filtration system 2 and the produced water system 3 in sequence, which can shorten the water purification process. At the same time, the device of the present application is located under the mine, occupies a small area, and has high treatment efficiency.

[0053] The above are all preferred embodiments of the present application, and are not intended to limit the scope of protection of the present application. Therefore, any equivalent changes made based on the structure, shape, and principle of the present application should be included in the scope of protection of the present application.

Claims

1. A nanofiltration treatment device for underground mine water, characterized by: It includes a pre-filtration system (1), a filtration system (2) and a water production system (3); The pre-filtration system (1) comprises a raw water pump (11) and a filter (12), wherein the water inlet of the raw water pump (11) is connected to the mine water, and the water outlet of the raw water pump (11) is connected to the water inlet of the filter (12) via a first connecting pipe (121); The filtration system (2) comprises a circulation pump (21), a switching valve group (22) and a nanofiltration membrane (231) assembly (23); the water inlet of the circulation pump (21) is connected to the water outlet of the filter (12) via a second connecting pipe (122); the switching valve group (22) is connected to the water outlet of the circulation pump (21) via a fourth connecting pipe (212); and the switching valve group (22) is connected to the nanofiltration membrane (231) assembly (23) via a fifth connecting pipe (223); The water production system (3) comprises a water production pipe (31) and a water production tank (32), wherein the water production pipe (31) is used to connect the nanofiltration membrane (231) component (23) and the water production tank (32).

2. The nanofiltration treatment device for underground mine water according to claim 1, characterized in that: A third connecting pipe (123) is installed in parallel between the first connecting pipe (121) and the second connecting pipe (122).

3. The nanofiltration treatment device for underground mine water according to claim 1, characterized in that: The nanofiltration membrane assembly (23) comprises a plurality of nanofiltration membranes (231), and the plurality of nanofiltration membranes (231) are connected in parallel.

4. The nanofiltration treatment device for underground mine water according to claim 3, characterized in that: The nanofiltration membrane (231) has two water inlet ends. The switching valve group (22) includes two valve group pipelines. The two valve group pipelines are arranged in parallel. Each valve group pipeline is connected to the circulation pump (21) through a fifth connecting pipe (223). Each valve group pipeline includes an eighth valve (221) and a ninth valve (222). A fifth connecting pipe (223) is installed between the eighth valve (221) and the ninth valve (222) on each valve group pipeline. The two fifth connecting pipes (223) are respectively connected to the two water inlet ends on the nanofiltration membrane (231).

5. The nanofiltration treatment device for underground mine water according to claim 4, characterized in that: A circulation pipe (5) connected to the water inlet end of the circulation pump (21) is installed on the switching valve group (22).

6. The nanofiltration treatment device for underground mine water according to claim 5, characterized in that: A drainage pipe (6) is installed on the circulation pipe (5).

7. The nanofiltration treatment device for underground mine water according to claim 6, characterized in that: Two drainage pipes (6) are provided, and the pipe openings of the two drainage pipes (6) have different diameters.

8. The nanofiltration treatment device for underground mine water according to claim 1, characterized in that: The second connecting pipe (122) is equipped with a pipeline mixer (4), the pipeline mixer (4) is equipped with a scale inhibitor tank (41) and an acidic drug tank (42), the produced water tank (32) is equipped with a backwash pump (7), and the backwash pump (7) is connected to the second connecting pipe (122) through a return pipe (8).

9. The nanofiltration treatment device for underground mine water according to claim 8, characterized in that: The backwash pump (7) is connected to the nanofiltration membrane (231) assembly (23) via a backwash pipe (9).

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