CN117509822A

CN117509822A - Water purification device, underground film self-cleaning sewage treatment system and method

Info

Publication number: CN117509822A
Application number: CN202311611247.2A
Authority: CN
Inventors: 葛光荣; 邢望; 王玉; 刘程; 张全; 王治宙; 胡骁
Original assignee: XI'AN RESEARCH INSTITUTE OF CHINA COAL RESEARCH INSTITUTE
Current assignee: XI'AN RESEARCH INSTITUTE OF CHINA COAL RESEARCH INSTITUTE
Priority date: 2023-11-29
Filing date: 2023-11-29
Publication date: 2024-02-06

Abstract

The invention provides a water purifying device, a system and a method for automatically cleaning sewage by using an underground membrane, wherein the water purifying device comprises a water purifying cylinder, a plurality of water purifying membranes are rotatably arranged in the water purifying cylinder, a plurality of spray pipes are fixedly arranged in the water purifying cylinder, and the spray pipes and the water purifying membranes which are positioned in the same vertical plane are arranged in a staggered manner. The system comprises a raw water tank, a raw water inlet pipeline, a raw water conveying pipeline, a normal flushing pipeline, a produced water conveying pipeline, a clean water tank and a back flushing pipeline which are communicated with the water purifying device. The method mainly comprises raw water extraction, water body purification and produced water extraction. The water purifying device realizes self-cleaning of the membrane through ingenious layout of the water purifying membrane and the highly dense spraying system, and remarkably improves the efficiency of treating underground sewage. The system provides a structural foundation for realizing efficient intelligent and automatic water purification. The method can intelligently adjust key parameters of each flushing stage, and ensures that the water purifying membrane is continuously in a high-flux working state, thereby improving the sewage treatment effect.

Description

Water purification device, underground film self-cleaning sewage treatment system and method

Technical Field

The invention belongs to the technical field of sewage treatment, relates to underground sewage treatment, and in particular relates to a water purifying device, an underground membrane self-cleaning sewage treatment system and an underground membrane self-cleaning sewage treatment method.

Background

The large amount of downhole water produced from coal mine downhole water contains harmful substances such as coalbed methane, stains and heavy metals. If not treated, serious pollution is caused to underground water and surface water, and safety accidents such as underground gas explosion and the like can be caused. However, transporting the downhole water directly to the surface for disposal and disposal is cumbersome and costly; on the contrary, if the underground water is directly purified in the exploitation process to obtain clear water, not only can the sewage transportation cost be saved, but also the purified water can be directly used for underground exploitation, thereby saving energy input, reducing environmental pollution and finally improving the exploitation efficiency.

However, most of the existing water purifying apparatuses are floor water purifying apparatuses, and because the floor space and the ground space are relatively wide, the floor water purifying apparatuses tend to be huge in size and cannot be directly transported to the underground for application, and therefore, development of an efficient sewage treatment apparatus suitable for the underground is needed. In addition, in the process of purifying the water body, the existing water purifying equipment has difficulty in intelligently adjusting the process route and specific process parameters of each stage (such as forward flushing, back flushing and the like) according to the real-time working condition, which further hinders the water purifying efficiency.

Disclosure of Invention

Aiming at the defects existing in the prior art, the invention aims to provide a water purifying device, an underground membrane self-cleaning sewage treatment system and an underground membrane self-cleaning sewage treatment method, and solve the technical problem that the sewage treatment efficiency in the underground is to be further improved in the prior art.

In order to solve the technical problems, the invention adopts the following technical scheme:

the underground membrane self-cleaning sewage treatment system comprises a raw water tank, wherein the water outlet end of the raw water tank is communicated with the water inlet end of a raw water inlet pipeline, the first water outlet end of the raw water inlet pipeline is communicated with the water inlet end of a raw water conveying pipeline, and the water outlet end of the raw water conveying pipeline is communicated with the first water inlet end of a water purifying device; the second water outlet end of the raw water inlet pipeline is communicated with the water inlet end of the normal flushing pipeline, and the water outlet end of the normal flushing pipeline is communicated with the second water inlet end of the water purifying device; the top of the water purifying device is provided with a clear water pipeline, the clear water pipeline is communicated with the water inlet end of the water producing conveying pipeline, the water outlet end of the water producing conveying pipeline is communicated with the water inlet end of the clear water tank, the water outlet end of the clear water tank is communicated with the water inlet end of the back flushing pipeline, and the water outlet end of the back flushing pipeline is communicated with the clear water pipeline.

The raw water inlet pipeline is provided with a raw water turbidity meter; the raw water conveying pipeline is provided with a water inlet pump and a raw water flowmeter; the positive flushing pipeline is provided with a positive flushing pump, a positive flushing flowmeter and a positive flushing pressure sensor; the water production conveying pipeline is provided with a water production pressure sensor, a water production water outlet pump, a water production flowmeter and a water production turbidity meter; the back flushing pipeline is provided with a back flushing pump, a back flushing flowmeter and a back flushing pressure sensor.

The water purifying device comprises a water purifying cylinder, wherein a main rotating shaft is arranged at the center of the inside of the water purifying cylinder along the axial direction, and a plurality of water purifying diaphragms are fixedly and rotatably arranged on the main rotating shaft; the water purifying device is characterized in that a motor support plate is fixedly arranged on the top end of the water purifying cylinder, a motor and a gear box are fixedly arranged on the top surface of the motor support plate, a first gear and a second gear which are meshed with each other are arranged on the gear box, the first gear is connected with the motor, the second gear is arranged on the top end of the main rotating shaft, and the motor drives the first gear and the second gear to rotate through driving, so that the main rotating shaft and the water purifying membrane are driven to rotate.

The bottom of the water purifying cylinder is internally and fixedly provided with an annular water conveying pipe, the annular water conveying pipe is fixedly connected with a plurality of axial water conveying pipes, the plurality of axial water conveying pipes are close to the inner wall of the water purifying cylinder and are uniformly distributed along the circumferential direction, the inner sides of the annular water conveying pipe and the axial water conveying pipe are fixedly connected with a plurality of spray pipes, and the spray pipes are arranged along the radial direction.

The plurality of spray pipes located in the same horizontal plane are evenly distributed along the circumferential direction, the plurality of water purifying films located in the same horizontal plane are evenly distributed along the circumferential direction, the plurality of spray pipes located in the same vertical plane are staggered with the plurality of water purifying films, the plurality of nozzles on the spray pipes are divided into two rows, the two rows of nozzles are respectively located on the upper side and the lower side of the spray pipes and are symmetrically arranged, and the water outlet direction of the nozzles faces the water purifying films.

The invention also has the following technical characteristics:

the main rotating shaft is rotatably provided with a plurality of diaphragm mounting shafts, the diaphragm mounting shafts are fixedly connected with diaphragm mounting frames, water purifying diaphragms are fixedly mounted in the diaphragm mounting frames, diaphragm supporting pipes are fixedly mounted in the diaphragm mounting frames on the back sides of the water purifying diaphragms, and diaphragm fixing pieces are mounted on the diaphragm mounting frames on the inner sides and the outer sides of the water purifying diaphragms.

The bottom of the water purifying device is provided with a sewage sludge pipeline which is communicated with the sludge box, and the sewage sludge pipeline is provided with a sewage valve.

The raw water conveying pipeline is provided with a raw water control valve; the positive flushing pipeline is provided with a positive flushing control valve; the water production control valve is arranged on the water production conveying pipeline; and a backwash control valve is arranged on the backwash pipeline.

The invention also provides a method for treating the self-cleaning sewage by the underground membrane, which adopts the system for treating the self-cleaning sewage by the underground membrane; the method specifically comprises the following steps:

step one, raw water extraction:

step 1.1, starting a water inlet pump, and starting to extract raw water;

step 1.2, when the raw water flows through the raw water turbidity meter, the raw water turbidity meter detects the raw water, if the turbidity of the raw water exceeds the standard, the frequency of the water inlet pump is reduced, and if the turbidity of the raw water does not exceed the standard, the frequency of the water inlet pump is not changed and the raw water is continuously extracted;

step 1.3, raw water flows into the water purifying device through a raw water inlet pipeline;

step two, purifying water body:

step 2.1, purifying raw water according to the purification parameters: after the raw water enters the water purifying device, the raw water is sprayed onto the water purifying membrane through the annular water conveying pipe, the axial water conveying pipe and the spraying pipe, and then the sludge in the raw water is separated through the set purifying parameters to generate produced water.

And 2.2, monitoring and acquiring the water production pressure and the membrane flux in real time in the raw water purification process, and judging whether the water production pressure and the membrane flux reach a threshold value or not.

Step 2.3, carrying out positive flushing or continuously pumping produced water:

if the step 2.2 judges that the water pressure and the membrane flux reach the preset threshold values, the water inlet pump is turned off, after the flushing time, the intensity and the frequency of the positive flushing are set, the positive flushing pump is started to pump the water from the clean water tank so as to carry out the positive flushing; if the produced water pressure or the membrane flux does not reach the preset threshold value, the produced water is continuously pumped into the clean water tank through the produced water outlet pump (20).

And 2.4, stopping the system operation or continuously pumping the produced water:

and 2.4.1, presetting a threshold value of the turbidity of the water body in a monitoring control system.

2.4.2, in the process of purifying raw water, monitoring and obtaining the produced water turbidity in real time through a produced water turbidity meter, and if the monitored produced water turbidity reaches the threshold value preset in the step 2.4.1, immediately triggering an alarm system to stop the operation of the underground membrane self-cleaning sewage treatment system; if the monitored turbidity of the produced water does not reach the preset threshold value, continuously pumping the produced water through the produced water outlet pump.

Specifically, the step 2.2 includes the following steps:

and 2.2.1, presetting a water pressure threshold value and a membrane flux threshold value in a monitoring control system.

And 2.2.2, monitoring and acquiring the water production pressure in real time through a water production pressure sensor in the process of purifying the raw water.

And 2.2.3, obtaining the water flow in unit time through a water production flow meter in the process of purifying the raw water.

Step 2.2.4, calculating and obtaining total water yield in a sampling time period according to the water yield obtained in the step 2.2.3, and calculating and obtaining membrane flux according to the water yield, wherein the calculation of the membrane flux is carried out according to the following formula I:

Wherein:

j represents membrane flux in L/m ² ·h。

V represents the total water yield in L during the sampling period.

T represents the sampling period in hours.

A represents the effective total area of the film, and the unit is m ² 。

And 2.2.5, comparing the water production pressure monitored in the step 2.2.2 with a threshold value of the water production pressure preset in the step 2.2.1 by adopting a monitoring control system, comparing the membrane flux obtained in the step 2.2.4 with the membrane flux threshold value preset in the step 2.2.1 by adopting the monitoring control system, and judging whether the water production pressure and the membrane flux reach the threshold values or not.

And 2.2.6, monitoring the membrane flux periodically to ensure the performance of the underground membrane self-cleaning sewage treatment system and calibrating timely.

Optionally and specifically, the method further comprises the steps of:

step three, forward flushing and back flushing:

and 3.1, closing a water producing and discharging pump, after setting the flushing time, intensity and frequency of the normal flushing, starting the normal flushing pump to pump raw water from the raw water tank, and spraying the raw water into a water purifying device through an annular water delivery pipe, an axial water delivery pipe and a spray pipe after the raw water flows into the water purifying device through the normal flushing pipeline so as to perform normal flushing.

And 3.2, monitoring and acquiring the water pressure and the membrane flux in real time in the positive flushing process, and judging whether the water pressure and the membrane flux reach the threshold values or not.

Step 3.3, back flushing or restarting water purification:

if the step 3.2 judges that the water pressure and the membrane flux reach the preset threshold values, properly adjusting the flushing time of the positive flushing, and then repeating the step 3.2; if the water pressure and the membrane flux still reach or exceed the preset threshold after the set positive flushing times, starting a backwash pump to pump produced water from the clean water tank for backwash; if the water pressure and the membrane flux are smaller than the preset threshold value within the set positive flushing times, starting the water producing and discharging pump and restarting purifying the raw water.

And 3.4, in the back flushing process, monitoring and acquiring the water pressure and the membrane flux in real time, and judging whether the water pressure and the membrane flux reach the threshold value or not:

step 3.5, stopping back flushing or restarting water purification:

if the step 3.4 judges that the water pressure and the membrane flux both reach the preset threshold values, the flushing time of back flushing is properly adjusted, and then the step 3.4 is repeated; if the water pressure and the membrane flux still reach or exceed the preset threshold after the set backwashing times, an alarm system is immediately triggered to stop backwashing; if the water pressure and the membrane flux are smaller than the preset threshold value within the set backwashing times, starting the water producing and discharging pump and restarting purifying the raw water.

And 3.6, stopping the system operation or continuously pumping the produced water:

in the process of restarting purifying raw water, monitoring and acquiring the produced water turbidity in real time through a produced water turbidity meter, and if the monitored produced water turbidity reaches a threshold value preset in the step 2.4.1, immediately triggering an alarm system to stop the operation of the underground membrane self-cleaning sewage treatment system; if the monitored turbidity of the produced water does not reach the preset threshold value, continuously pumping the produced water through the produced water outlet pump.

Specifically, the step 3.2 includes the following steps:

and 3.2.1, monitoring and acquiring water pressure in real time through a positive flushing pressure sensor in the positive flushing process.

And 3.2.2, obtaining the water flow in unit time through the positive flushing flowmeter in the positive flushing process.

Step 3.2.3, calculating and obtaining total water flow in a sampling time period according to the water flow obtained in the step 3.2.2, and calculating and obtaining membrane flux according to the water flow; the calculation procedure is the same as step 2.2.4.

And 3.2.4, comparing the water pressure monitored in the step 3.2.1 with a preset water pressure threshold in the step 2.2.1 by adopting a monitoring control system, comparing the membrane flux obtained in the step 3.2.3 with the preset membrane flux threshold in the step 2.2.1 by adopting the monitoring control system, and judging whether the water pressure and the membrane flux reach the threshold or not.

Specifically, the step 3.4 includes the following steps:

and 3.4.1, monitoring and acquiring the water pressure in real time through a backwashing pressure sensor in the backwashing process.

In the back flushing process, the water flow in unit time is obtained through a back flushing flowmeter in step 3.4.2.

And 3.4.3, calculating and obtaining the total water flow in the sampling time period according to the water flow obtained in the step 3.4.2, and calculating and obtaining the membrane flux according to the water flow.

And 3.4.4, comparing the water pressure monitored in the step 3.4.1 with a preset water pressure threshold in the step 2.2.1 by adopting a monitoring control system, comparing the membrane flux obtained in the step 3.4.3 with the preset membrane flux threshold in the step 2.2.1 by adopting the monitoring control system, and judging whether the water pressure and the membrane flux reach the threshold or not.

The invention also provides a water purifying device.

Compared with the prior art, the invention has the following technical effects:

according to the water purifying device disclosed by the invention, the plurality of spraying pipes are arranged around the water purifying membrane and are mutually staggered with the water purifying membrane, so that the self-cleaning function of the membrane is effectively realized; and a plurality of spray pipes are adopted for spraying up and down simultaneously, so that the flushing area is effectively increased, the utilization rate of the membrane and the water production speed are improved, and the flushing efficiency is further improved. In conclusion, the self-cleaning of the membrane is realized through the ingenious layout of the water purification membrane and the highly dense spraying system, and the efficiency of treating underground sewage is remarkably improved.

(II) according to the water purifying device disclosed by the invention, all the water purifying membranes can adjust the inclination angle, so that the sludge can be ensured to fall off rapidly, and further, the self-cleaning task of the membranes can be ensured to be completed efficiently.

And (III) the purification device controls the water purification membrane to rotate forward and backward and the rotation speed through the motor, so that the sludge can fall off from the membrane more quickly, the water purification membrane is ensured to be in a high-efficiency working state all the time, and the waste water purification efficiency is improved.

The underground membrane self-cleaning sewage treatment system takes a water purifying device as core treatment equipment, and is provided with a raw water extracting mechanism (mainly comprising a raw water tank, a water inlet pump, a raw water inlet pipe, a raw water control valve and a raw water conveying pipeline), a produced water extracting mechanism (comprising a produced water conveying pipeline, a clean water tank and a produced water outlet pump), a positive flushing mechanism (comprising a positive flushing pipeline, a positive flushing control valve and a positive flushing pump), a back flushing mechanism (comprising a back flushing pipeline, a back flushing control valve and a back flushing pump) and a water quality real-time monitoring mechanism (comprising a turbidity meter, a flowmeter and a pressure sensor) in a matched manner, wherein the mechanisms provide a structural basis for realizing efficient automatic and intelligent water purification.

The underground membrane self-cleaning sewage treatment method disclosed by the invention skillfully fuses forward flushing and back flushing, and key parameters can be intelligently adjusted in each flushing stage, so that the water purification membrane is ensured to be in a high-flux working state continuously, and the sewage treatment effect is improved.

According to the underground membrane self-cleaning sewage treatment method disclosed by the invention, the whole water treatment process is monitored in real time and automatically controlled by combining the underground membrane self-cleaning sewage treatment system with the monitoring control system and the electric control system, so that the working flow is simplified, and the wastewater treatment efficiency is obviously improved.

Drawings

Fig. 1 is a schematic view of an external structure of a water purifying apparatus.

Fig. 2 is a sectional view showing an internal structure of the water purifying apparatus.

Fig. 3 is a cross-sectional view (perpendicular to the cross-section of fig. 2) of the internal structure of the water purifying apparatus.

Fig. 4 is a schematic diagram of the overall structure of the downhole membrane self-cleaning sewage treatment system.

Fig. 5 is a diagram of an overall process architecture of a downhole membrane self-cleaning wastewater treatment method.

Fig. 6 is a workflow diagram of raw water purification of a downhole membrane self-cleaning wastewater treatment method.

FIG. 7 is a positive flushing workflow diagram of a downhole membrane self-cleaning wastewater treatment method.

FIG. 8 is a forward flushing and back flushing workflow diagram of a downhole membrane self-cleaning wastewater treatment process.

FIG. 9 is a backwash workflow diagram of a downhole membrane self-cleaning wastewater treatment method.

The meaning of each reference numeral in the figures is: 1-raw water tank, 2-raw water inlet pipeline, 3-raw water conveying pipeline, 4-water purifying device, 5-forward flushing pipeline, 6-clear water pipeline, 7-produced water conveying pipeline, 8-clear water tank, 9-back flushing pipeline, 10-raw water turbidity meter, 11-raw water control valve, 12-water inlet pump, 13-raw water flowmeter, 14-forward flushing control valve, 15-forward flushing pump, 16-forward flushing flowmeter, 17-forward flushing pressure sensor, 18-produced water control valve, 19-produced water pressure sensor, 20-produced water outlet pump, 21-produced water flowmeter, 22-produced water turbidity meter, 23-back flushing pump, 24-back flushing flowmeter, 25-back flushing pressure sensor, 26-back flushing control valve, 27-blowdown mud pipeline, 28-blowdown valve.

401-water purifying cylinder, 402-main rotating shaft, 403-water purifying diaphragm, 404-motor supporting plate, 405-motor, 406-gear box, 407-first gear, 408-second gear, 409-annular water delivery pipe, 410-axial water delivery pipe, 411-spraying pipe, 412-diaphragm mounting shaft, 413-diaphragm mounting frame, 414-diaphragm supporting pipe, 415-diaphragm fixing piece, 416-water purifying cylinder cover plate.

40101-barrel body, 40102-support legs, 40103-top annular support, 40104-bottom annular support.

The following examples illustrate the invention in further detail.

Detailed Description

All parts of the present invention, unless otherwise specified, are known in the art, for example:

the water purification membrane 403 employs a conventional ceramic filter membrane known in the art.

Diaphragm mounting shaft 412 employs a conventional damped shaft as known in the art.

The motor 405 employs a conventional variable frequency gear motor known in the art, which is controllable in speed and direction.

The raw water turbidimeter 10 and the produced water turbidimeter 22 are conventional turbidimeters known in the art, which are instruments for measuring the concentration or turbidity of suspended particulate matter in a liquid, the principle of which is based on the measurement of scattered light, and a detector is provided in the turbidimeter for measuring the intensity and distribution angle of the scattered light. Finally, by measuring the intensity and direction of the scattered light, the turbidity meter can calculate the turbidity or particle concentration in the liquid.

The raw water control valve 11, the forward flushing control valve 14, the produced water control valve 18, the back flushing control valve 26 and the sewage valve 29 are all conventional electric valves known in the art, and the electric valves are used for controlling the opening and closing of the pipeline and controlling the flow rate of water or sludge in the pipeline by adjusting the opening degree.

The intake pump 12 and the produced water outlet pump 20 are conventional pumps known in the art for driving the flow of water within the pipeline to draw the water into the purification apparatus.

The raw water flow meter 13, the forward flushing flow meter 16, the produced water flow meter 21 and the back flushing flow meter 24 are conventional flow meters known in the art, and are used for detecting the flow rate of the liquid in the pipeline per unit time.

Both the forward and reverse wash pumps 15, 23 employ conventional rinse pumps known in the art, which are typically designed to handle a variety of liquids, including produced water, sewage and chemical liquids, and operate on a principle that is basically mechanical, drawing water or liquid from one location to another for further processing or distribution.

The positive backwash pressure sensor 17, the produced water pressure sensor 19 and the backwash pressure sensor 25 are all conventional pressure sensors known in the art for detecting the water pressure of the liquid in the pipeline.

The following specific embodiments of the present invention are provided, and it should be noted that the present invention is not limited to the following specific embodiments, and all equivalent changes made on the basis of the technical solutions of the present application fall within the protection scope of the present invention.

Example 1:

the present embodiment provides a water purifying apparatus, as shown in fig. 1 to 3, comprising a water purifying cartridge 401, wherein a main rotating shaft 402 is provided at the center of the inside of the water purifying cartridge 401 along the axial direction, and a plurality of water purifying films 403 are fixedly and rotatably installed on the main rotating shaft 402; a motor support plate 404 is fixedly arranged at the top end of the water purifying cylinder 401, a motor 405 and a gear box 406 are fixedly arranged on the top surface of the motor support plate 404, the gear box 406 is provided with a first gear 407 and a second gear 408 which are meshed with each other, the first gear 407 is connected with the motor 405, the second gear 408 is arranged at the top end of the main rotating shaft 402, and the motor 405 drives the main rotating shaft 402 and the water purifying membrane 403 to rotate by driving the first gear 407 and the second gear 408 to rotate; an annular water delivery pipe 409 is fixedly arranged in the bottom of the water purification barrel 401, a plurality of axial water delivery pipes 410 are fixedly connected to the annular water delivery pipe 409, the plurality of axial water delivery pipes 410 are close to the inner wall of the water purification barrel 401 and are uniformly distributed along the circumferential direction, a plurality of spray pipes 411 are fixedly connected to the annular water delivery pipe 409 and the inner side of the axial water delivery pipe 410, and the spray pipes 411 are arranged along the radial direction; the plurality of spray pipes 411 located in the same horizontal plane are evenly distributed along the circumferential direction, the plurality of water purifying films 403 located in the same horizontal plane are evenly distributed along the circumferential direction, the plurality of spray pipes 411 and the plurality of water purifying films 403 located in the same vertical plane are arranged in a staggered mode, the plurality of nozzles on the spray pipes 411 are divided into two rows, the two rows of nozzles are respectively located on the upper side and the lower side of the spray pipes 411 and are symmetrically arranged, and the water outlet direction of the nozzles faces the water purifying films 403.

In the embodiment, the filtering direction of the device is from outside to inside when purifying the water body, and the water body is sprayed with water from the upper direction and the lower direction simultaneously to realize simple flushing of the water purifying membrane 403 through a spraying system consisting of the annular water pipe 409, the axial water pipe 410 and the spraying pipe 411; as filtration proceeds, centrifugation causes the fluid to form strong cross-flow on the surface of the water purification membrane 403; due to the high shearing action of the fluid on the surface of the water purifying membrane 403, the surface of the water purifying membrane 403 can be effectively scrubbed, concentration polarization is weakened, and pollution of the water purifying membrane 403 is reduced, so that the filtering operation can keep a continuous and stable filtering state, and the self-cleaning function of the water purifying membrane 403 is realized.

In this embodiment, the shower 411 sprays water onto the water purifying membrane 403 through the upper and lower rows of nozzles, so that not only can the utilization rate and the water producing speed of the water purifying membrane 403 be improved, but also the flushing area can be effectively increased in the flushing process, and the flushing efficiency is greatly improved.

In this embodiment, the forward and reverse rotation of the water purifying membrane 403 can be realized by controlling the forward and reverse rotation of the motor 405, and the rotation speed of the water purifying membrane 403 can be controlled by controlling the frequency of the motor 405, so that the sludge can be ensured to fall off more rapidly, thereby keeping the membrane in a high-efficiency working state all the time, and improving the purifying efficiency.

As a specific scheme of this embodiment, as shown in fig. 2 to 3, a plurality of membrane mounting shafts 412 are rotatably mounted on the main rotating shaft 402, a membrane mounting frame 413 is fixedly connected to the membrane mounting shaft 412, a water purifying membrane 403 is fixedly mounted in the membrane mounting frame 413, a membrane supporting tube 414 is fixedly mounted in the membrane mounting frame 413 on the back side of the water purifying membrane 403, and membrane fixing members 415 are mounted on the membrane mounting frames 413 on the inner side and the outer side of the water purifying membrane 403.

In this embodiment, the total number of the water purifying membrane 403 is 30, the water purifying membrane 403 is fixed at two ends by the membrane fixing piece 415 made of nylon material, in addition, the membrane supporting tube 414 made of aluminum material is arranged on the back surface of the water purifying membrane 403 to further strengthen the support, and the membrane mounting shaft 412 can rotate by 360 degrees, so that the water purifying membrane 403, the membrane mounting frame 413, the membrane supporting tube 414 and the membrane fixing piece 415 are driven to rotate as a whole. The mounting structure has the advantages of the following three aspects: first, there is flexibility in that the angle of the water purifying membrane 403 can be adjusted as needed. Second, it is strong, i.e., it is possible to secure the water purifying membrane 403 during operation and rotation. Thirdly, the water purifying membrane 403 has high efficiency, namely, the sludge is easier to slide under the action of gravity due to the inclined arrangement of the water purifying membrane 403.

As a specific scheme of the embodiment, as shown in fig. 1, the bottom end of the water purifying cartridge 401 has an inverted conical structure; in this embodiment, this kind of structure of water purification section of thick bamboo 401 bottom is favorable to mud gathering in the bottom of water purification section of thick bamboo 401, conveniently later stage discharge.

As a specific scheme of the embodiment, as shown in fig. 1, a water purifying cartridge cover plate 416 is installed on the top ends of the water purifying cartridges 401 on both sides of the motor support plate 404; in this embodiment, the cleaning bowl cover 416 prevents sludge and water from splashing out of the cleaning bowl 401 during agitation.

As a specific scheme of this embodiment, as shown in fig. 1 to 3, the water purifying cartridge 401 includes a cartridge body 40101, and a space enclosed by the cartridge body 40101 and the water purifying cartridge cover plate 416 is a water purifying tank; a plurality of support legs 40102 are fixedly arranged outside the cylinder body 40101, and the plurality of support legs 40102 are uniformly distributed along the circumferential direction of the water purifying cylinder 401; a top annular bracket 40103 is arranged in the top of the barrel body 40101, a bottom annular bracket 40104 is arranged in the bottom of the barrel body 40101, and the top annular bracket 40103 and the bottom annular bracket 40104 are fixedly connected with a plurality of support legs 40102; the main shaft 402 is disposed at the center of the top ring support 40103 and the bottom ring support 40104; the annular water duct 409 is fixedly mounted on the bottom annular support 40104. In this embodiment, the structure composed of the support leg 40102, the top annular bracket 40103 and the bottom annular bracket 40104 has a supporting effect on the water purifying cartridge 401, and ensures the stability of the water purifying cartridge 401.

As a specific solution of this embodiment, the annular water pipe 409, the top annular support 40103 and the bottom annular support 40104 are all of hexagonal annular structures, which is beneficial to maintaining the stability of the device as a whole.

Example 2:

the present embodiment provides an underground membrane self-cleaning sewage treatment system with a water purifying device of embodiment 1, as shown in fig. 4, the system includes a raw water tank 1, a water outlet end of the raw water tank 1 is communicated with a water inlet end of a raw water inlet pipe 2, a first water outlet end of the raw water inlet pipe 2 is communicated with a water inlet end of a raw water conveying pipe 3, and a water outlet end of the raw water conveying pipe 3 is communicated with a first water inlet end of a water purifying device 4; the second water outlet end of the raw water inlet pipeline 2 is communicated with the water inlet end of the normal flushing pipeline 5, and the water outlet end of the normal flushing pipeline 5 is communicated with the second water inlet end of the water purifying device 4; the top of purifier 4 is provided with clear water pipeline 6, and clear water pipeline 6 is linked together with the water inlet end of producing water pipeline 7, and the water outlet end of producing water pipeline 7 is linked together with the water inlet end of clear water tank 8, and the water outlet end of clear water tank 8 is linked together with the water inlet end of back flush pipeline 9, and the water outlet end of back flush pipeline 9 is linked together with clear water pipeline 6.

As a specific scheme of the present embodiment, a raw water turbidity meter 10 is provided on the raw water intake pipe 2. In this embodiment, the raw water turbidity meter 10 can monitor the turbidity of raw water in real time, and when the indication of the raw water turbidity meter 10 is high, it is indicated that the turbidity of raw water is too high, and the frequency of the water inlet pump 12 and the forward washing pump 15 needs to be adjusted, so that the speed of raw water entering the water purifying device 4 is reduced, and the purifying effect of raw water is ensured.

As a specific scheme of the present embodiment, a raw water control valve 11, a water intake pump 12, and a raw water flow meter 13 are sequentially provided on the raw water transport pipe 3 along the water flow direction.

As a specific scheme of the present embodiment, a positive flushing control valve 14, a positive flushing pump 15, a positive flushing flowmeter 16, and a positive flushing pressure sensor 17 are provided in this order along the water flow direction on the positive flushing pipe 5.

As a specific scheme of the embodiment, a water production control valve 18, a water production pressure sensor 19, a water production outlet pump 20, a water production flow meter 21 and a water production turbidity meter 22 are sequentially arranged on the water production conveying pipeline 7 along the water flow direction.

As a specific scheme of the embodiment, a backwash pump 23, a backwash flowmeter 24, a backwash pressure sensor 25 and a backwash control valve 26 are sequentially arranged on the backwash pipeline 9 along the water flow direction.

As a specific scheme of the embodiment, a sewage sludge pipeline 27 is arranged at the bottom of the water purifying device 4, the sewage sludge pipeline 27 is communicated with a sludge tank 28, and a sewage valve 29 is arranged on the sewage sludge pipeline 27. In this embodiment, when the sludge is to be discharged, the sewage valve 29 is opened, and the sludge flows into the sludge tank 28 along the sewage sludge pipe 27.

Example 3:

the embodiment provides a method for treating sewage by self-cleaning of an underground membrane, which adopts the sewage treatment system for self-cleaning of the underground membrane of the embodiment 2 to realize the purification of raw water. As shown in fig. 5, the main processes of the method include raw water extraction, water purification and produced water extraction. The method specifically comprises the following steps:

step one, raw water is extracted, specifically as shown in fig. 6:

step 1.1, starting the water inlet pump 12 by adopting an electric control system, and starting to extract raw water.

Step 1.2, when the raw water flows through the raw water turbidity meter 10, the raw water turbidity meter 10 detects the raw water, if the turbidity of the raw water exceeds the standard, the electric control system is adopted to reduce the frequency of the water inlet pump 12, and if the turbidity of the raw water does not exceed the standard, the frequency of the water inlet pump 12 is not changed and the raw water is continuously extracted.

Step 1.3, raw water flows into the water purifying device 4 through the raw water inlet pipeline 2.

Step two, purifying water body:

step 2.1, purifying raw water according to the purification parameters: after the raw water enters the water purifying device 4, the raw water is sprayed onto the water purifying membrane 403 through the annular water conveying pipe 409, the axial water conveying pipe 410 and the spraying pipe 411, and then the sludge in the raw water is separated and the produced water is generated through the set purifying parameters.

In order to ensure a better water purifying effect, according to the rotation speed and the rotation direction of the water purifying membrane 403, three modes capable of being freely switched are designed in this embodiment:

the purge parameters for the first mode are as follows: the water purifying film 403 rotates clockwise for 10 seconds and then rotates counterclockwise for 10 seconds, and the speeds of both clockwise rotation and counterclockwise rotation are 20r/min.

The purge parameters for the second mode are as follows: the water purifying membrane 403 always rotates clockwise or counterclockwise, and the speed of both clockwise and counterclockwise rotation is 20r/min.

The purge parameters for the third mode are as follows: the water purifying film 403 rotates clockwise for 10 seconds, and the clockwise rotation speed is 25r/min; and the rotation is carried out for 15 seconds anticlockwise, and the anticlockwise rotation speed is 20r/min.

In this embodiment, under the action of gravity, by virtue of the forward and reverse transfer and different speeds of the three modes, the sludge can be caused to fall from the membrane more rapidly, so that the water purifying membrane 403 is always in a high-efficiency working state, and the purification efficiency is improved.

Step 2.2, in the raw water purification process, monitoring and acquiring the water production pressure and the membrane flux in real time, and judging whether the water production pressure and the membrane flux reach a threshold value or not:

2.2.1, presetting a water pressure threshold value and a membrane flux threshold value in a monitoring control system; the preset threshold needs to be guaranteed to be within normal operating ranges to avoid frequent flushing.

Step 2.2.2, monitoring and obtaining the water pressure in real time through the water pressure sensor 19 in the process of purifying the raw water; if the water production pressure drops to or above a threshold value, this indicates that the membrane or filtration media may have become clogged.

Step 2.2.3, during the purification of raw water, the water flow per unit time (usually in liters/hour) is obtained by the water-producing flowmeter 21.

Step 2.2.4, calculating and obtaining the total water yield in the sampling period according to the water yield obtained in step 2.2.3, and calculating and obtaining the membrane flux according to the water yield (the membrane flux refers to the water yield passing through per unit of membrane surface area in the purification process, and is generally expressed in units of volume/time/area or volume/time); the membrane flux was calculated using the following formula i:

wherein:

j represents membrane flux in L/m ² ·h。

V represents the total water yield in L during the sampling period.

T represents the sampling period in hours.

A represents the effective total area of the film, and the unit is m ² 。

In this embodiment, the calculation of the membrane flux is critical to the monitoring and control of the membrane separation process, because it can reflect the performance of the downhole membrane self-cleaning wastewater treatment system and the permeability of the membrane, and in addition, it can be used to optimize the operation of the downhole membrane self-cleaning wastewater treatment system and detect any possible problems.

And 2.2.5, comparing the water production pressure monitored in the step 2.2.2 with a threshold value of the water production pressure preset in the step 2.2.1 by adopting a monitoring control system, comparing the membrane flux obtained in the step 2.2.4 with the membrane flux threshold value preset in the step 2.2.1 by adopting the monitoring control system, and judging whether the water production pressure and the membrane flux reach the threshold values or not. In this embodiment, the monitoring control system is computer software known in the prior art, and the flushing program carried by the monitoring control system can be finely controlled, so as to ensure that the underground membrane self-cleaning sewage treatment system continuously and efficiently operates.

And 2.2.6, monitoring the membrane flux periodically to ensure the performance of the underground membrane self-cleaning sewage treatment system and calibrating timely. Since membrane flux decays over time, maintaining a downhole membrane self-cleaning wastewater treatment system is very important to maintain a stable flux.

Step 2.3, performing forward flushing or continuously pumping produced water, as shown in fig. 7:

if the step 2.2 judges that the water pressure and the membrane flux reach the preset threshold values, the water inlet pump (12) is turned off, and after the flushing time, the intensity and the frequency of the positive flushing are set by monitoring the flushing program of the control system, the positive flushing pump (15) is started to pump the water from the clean water tank 8 for positive flushing; if the produced water pressure or membrane flux does not reach the preset threshold, the produced water is continuously pumped into the clean water tank 8 by the produced water outlet pump 20.

In this embodiment, through the operations of the step 2.2 and the step 2.3, an automatic flushing process can be implemented, so as to maintain the performance of the underground membrane self-cleaning sewage treatment system and avoid production interruption, thereby being beneficial to improving the efficiency and ensuring the quality of produced water.

Step 2.4.2, in the process of purifying raw water, monitoring and obtaining the produced water turbidity in real time through a produced water turbidity meter 22, and if the monitored produced water turbidity reaches the threshold value preset in step 2.4.1, immediately triggering an alarm system to stop the operation of the underground membrane self-cleaning sewage treatment system; if the monitored turbidity of produced water does not reach the preset threshold, the produced water is continuously pumped through the produced water outlet pump 20.

As an alternative and optimized solution of the present embodiment, when monitoring the membrane flux, if the membrane flux is found to have decayed, the method further comprises the steps of:

step three, forward flushing and back flushing, specifically as shown in fig. 8 and 9:

step 3.1, the water producing outlet pump 20 is turned off, after the flushing time (default flushing time is 5 minutes), intensity and frequency of the normal flushing are set by the flushing program of the monitoring control system, the normal flushing pump 15 is started to pump raw water from the raw water tank 1, and after the raw water flows into the water purifying device 4 through the normal flushing pipeline 5, the raw water is sprayed to the water purifying membrane 403 through the annular water conveying pipe 409, the axial water conveying pipe 410 and the spraying pipe 411 to perform normal flushing.

And 3.2, in the positive flushing process, monitoring and acquiring the water pressure and the membrane flux in real time, and judging whether the water pressure and the membrane flux reach a threshold value or not:

step 3.2.1, during the positive flushing process, the water pressure is monitored and obtained in real time by the positive flushing pressure sensor 17.

Step 3.2.2, during the positive flushing process, the water flow per unit time is obtained by the positive flushing flowmeter 16.

Step 3.3, back flushing or restarting water purification:

if the step 3.2 judges that the water pressure and the membrane flux reach the preset threshold values, properly adjusting the flushing time of the positive flushing, and then repeating the step 3.2; if the water pressure and the membrane flux still reach or exceed the preset threshold after the set positive flushing times (the default times are 3 times), starting a backwash pump 23 to pump produced water from the clean water tank 8 for backwash; if the water pressure and the membrane flux are smaller than the preset threshold values within the set positive flushing times, the produced water outlet pump 20 is started and the raw water purification is restarted.

and 3.4.1, monitoring and acquiring the water pressure in real time through a back flush pressure sensor 25 during back flush.

In step 3.4.2, during the backwash process, the water flow per unit time is obtained through backwash flow meter 24.

Step 3.4.3, calculating and obtaining total water flow in a sampling time period according to the water flow obtained in the step 3.4.2, and calculating and obtaining membrane flux according to the water flow; the calculation procedure is the same as step 2.2.4.

Step 3.5, stopping back flushing or restarting water purification:

if the step 3.4 judges that the water pressure and the membrane flux both reach the preset threshold values, the flushing time of back flushing is properly adjusted, and then the step 3.4 is repeated; if the water pressure and the membrane flux still reach or exceed the preset threshold after the set backwashing times (the default times are 3 times), an alarm system is immediately triggered, and backwashing is stopped; if the water pressure and the membrane flux are smaller than the preset threshold value within the set backwashing times, the produced water outlet pump 20 is started and the raw water purification is restarted.

in the process of restarting purifying raw water, monitoring and acquiring the produced water turbidity in real time through a produced water turbidity meter 22, and if the monitored produced water turbidity reaches the threshold value preset in the step 2.4.1, immediately triggering an alarm system to stop the operation of the underground membrane self-cleaning sewage treatment system; if the monitored turbidity of produced water does not reach the preset threshold, the produced water is continuously pumped through the produced water outlet pump 20.

In this embodiment, through the operation of effectively combining the forward flushing and the back flushing in the third step, the water purifying membrane 403 can be ensured to be continuously in a high-flux working state, which is helpful for improving the efficiency and further stabilizing the water quality.

And (3) effect verification: by adopting the underground membrane self-cleaning sewage treatment system and method, 0.5 ton of sewage can be treated in each hour, and the efficient treatment of underground sewage is realized.

Claims

1. The utility model provides a self-cleaning sewage treatment system of underground membrane, includes former water tank (1), and the play water end of former water tank (1) is linked together with the inlet end of former water inlet channel (2) and is linked together with the inlet end of former water pipeline (3), its characterized in that:

The water outlet end of the raw water conveying pipeline (3) is communicated with the first water inlet end of the water purifying device (4); the second water outlet end of the raw water inlet pipeline (2) is communicated with the water inlet end of the normal flushing pipeline (5), and the water outlet end of the normal flushing pipeline (5) is communicated with the second water inlet end of the water purifying device (4); the top of the water purifying device (4) is provided with a clear water pipeline (6), the clear water pipeline (6) is communicated with the water inlet end of the water production conveying pipeline (7), the water outlet end of the water production conveying pipeline (7) is communicated with the water inlet end of the clear water tank (8), the water outlet end of the clear water tank (8) is communicated with the water inlet end of the back flushing pipeline (9), and the water outlet end of the back flushing pipeline (9) is communicated with the clear water pipeline (6);

a raw water turbidity meter (10) is arranged on the raw water inlet pipeline (2);

the raw water conveying pipeline (3) is provided with a water inlet pump (12) and a raw water flowmeter (13);

the positive flushing pipeline (5) is provided with a positive flushing pump (15), a positive flushing flowmeter (16) and a positive flushing pressure sensor (17);

a water production pressure sensor (19), a water production outlet pump (20), a water production flow meter (21) and a water production turbidity meter (22) are arranged on the water production conveying pipeline (7);

the back flushing pipeline (9) is provided with a back flushing pump (23), a back flushing flowmeter (24) and a back flushing pressure sensor (25);

The water purifying device (4) comprises a water purifying cylinder (401), a main rotating shaft (402) is arranged at the center of the inside of the water purifying cylinder (401) along the axial direction, and a plurality of water purifying diaphragms (403) are arranged on the main rotating shaft (402); a motor support plate (404) is fixedly arranged at the top end of the water purifying barrel (401), a motor (405) and a gear box (406) are fixedly arranged on the top surface of the motor support plate (404), a first gear (407) and a second gear (408) which are meshed with each other are arranged on the gear box (406), the first gear (407) is connected with the motor (405), the second gear (408) is arranged at the top end of the main rotating shaft (402), and the motor (405) drives the main rotating shaft (402) and the water purifying membrane (403) to rotate by driving the first gear (407) and the second gear (408);

an annular water delivery pipe (409) is fixedly arranged in the bottom of the water purification barrel (401), a plurality of axial water delivery pipes (410) are fixedly connected to the annular water delivery pipe (409), the plurality of axial water delivery pipes (410) are close to the inner wall of the water purification barrel (401) and are uniformly distributed along the circumferential direction, a plurality of spray pipes (411) are fixedly connected to the inner sides of the annular water delivery pipe (409) and the inner sides of the axial water delivery pipes (410), and the spray pipes (411) are arranged along the radial direction;

the plurality of spray pipes (411) located in the same horizontal plane are evenly distributed along the circumferential direction, the plurality of water purifying films (403) located in the same horizontal plane are evenly distributed along the circumferential direction, the plurality of spray pipes (411) located in the same vertical plane are staggered with the plurality of water purifying films (403), the plurality of nozzles on the spray pipes (411) are divided into two rows, the two rows of nozzles are respectively located on the upper side and the lower side of the spray pipes (411) and are symmetrically arranged, and the water outlet direction of the nozzles faces the water purifying films (403).

2. The downhole membrane self-cleaning sewage treatment system according to claim 1, wherein a plurality of membrane mounting shafts (412) are rotatably mounted on the main rotating shaft (402), a membrane mounting frame (413) is fixedly mounted on the membrane mounting shafts (412), a water purifying membrane (403) is fixedly mounted in the membrane mounting frame (413), a membrane supporting tube (414) is fixedly mounted in the membrane mounting frame (413) on the back side of the water purifying membrane (403), and membrane fixing pieces (415) are mounted on the membrane mounting frames (413) on the inner side and the outer side of the water purifying membrane (403).

3. The underground membrane self-cleaning sewage treatment system according to claim 1, wherein a sewage sludge pipeline (27) is arranged at the bottom of the water purifying device (4), the sewage sludge pipeline (27) is communicated with a sludge tank (28), and a sewage valve (29) is arranged on the sewage sludge pipeline (27).

4. A downhole membrane self-cleaning sewage treatment system according to claim 1, wherein the raw water delivery pipeline (3) is provided with a raw water control valve (11); a positive flushing control valve (14) is arranged on the positive flushing pipeline (5); a water production control valve (18) is arranged on the water production conveying pipeline (7); and a back flushing control valve (26) is arranged on the back flushing pipeline (9).

5. A method for treating sewage by self-cleaning of a downhole membrane, which is characterized in that the method adopts the sewage treatment system by self-cleaning of a downhole membrane according to any one of claims 1 to 4; the method specifically comprises the following steps:

step one, raw water extraction:

step 1.1, starting a water inlet pump (12) to start raw water extraction;

step 1.2, when raw water flows through the raw water turbidity meter (10), the raw water turbidity meter (10) detects the raw water, if the turbidity of the raw water exceeds the standard, the frequency of the water inlet pump (12) is reduced, and if the turbidity of the raw water does not exceed the standard, the frequency of the water inlet pump (12) is not changed, and the raw water is continuously extracted;

step 1.3, raw water flows into the water purifying device (4) through the raw water inlet pipeline (2);

step two, purifying water body:

step 2.1, purifying raw water according to the purification parameters: after raw water enters the water purifying device (4), the raw water is sprayed onto the water purifying membrane (403) through the annular water conveying pipe (409), the axial water conveying pipe (410) and the spraying pipe (411), and then sludge in the raw water is separated through the set purifying parameters to generate produced water;

step 2.2, monitoring and acquiring the water pressure and the membrane flux in real time in the raw water purification process, and judging whether the water pressure and the membrane flux reach a threshold value or not;

if the step 2.2 judges that the water production pressure and the membrane flux reach the preset threshold values, the water inlet pump (12) is closed, after the flushing time, the intensity and the frequency of the positive flushing are set, the positive flushing pump (15) is started to pump the water production from the clean water tank (8) for positive flushing; if the produced water pressure or the membrane flux does not reach the preset threshold value, continuously pumping the produced water into the clean water tank (8) through the produced water outlet pump (20);

step 2.4.1, presetting a threshold value of the turbidity of the water body in a monitoring control system;

2.4.2, in the process of purifying raw water, monitoring and obtaining the produced water turbidity in real time through a produced water turbidity meter (22), and if the monitored produced water turbidity reaches the threshold value preset in the step 2.4.1, immediately triggering an alarm system to stop the operation of the underground membrane self-cleaning sewage treatment system; if the monitored turbidity of the produced water does not reach the preset threshold value, the produced water is continuously extracted through the produced water outlet pump (20).

6. The method for treating sewage by self-cleaning a downhole membrane according to claim 5, wherein the step 2.2 comprises the steps of:

2.2.1, presetting a water pressure threshold value and a membrane flux threshold value in a monitoring control system;

2.2.2, in the process of purifying raw water, monitoring and acquiring the water production pressure in real time through a water production pressure sensor (19);

2.2.3, obtaining the water flow in unit time through a water production flow meter (21) in the process of purifying raw water;

wherein:

j represents membrane flux in L/m ² ·h；

V represents the total water yield in the sampling time period, and the unit is L;

t represents a sampling period in hours;

a represents the effective total area of the film, and the unit is m ² ；

Step 2.2.5, comparing the water production pressure monitored in step 2.2.2 with the threshold value of the water production pressure preset in step 2.2.1 by adopting a monitoring control system, comparing the membrane flux obtained in step 2.2.4 with the threshold value of the membrane flux preset in step 2.2.1 by adopting the monitoring control system, and judging whether the water production pressure and the membrane flux reach the threshold value or not;

7. The method for treating downhole membrane self-cleaning wastewater as claimed in claim 6, further comprising the steps of:

step three, forward flushing and back flushing:

step 3.1, closing a water producing and discharging pump (20), after setting the flushing time, intensity and frequency of the positive flushing, starting a positive flushing pump (15) to pump raw water from a raw water tank (1), and spraying the raw water into a water purifying device (4) through a positive flushing pipeline (5) to a water purifying membrane (403) through a circular water conveying pipe (409), an axial water conveying pipe (410) and a spraying pipe (411) to perform positive flushing;

step 3.2, monitoring and acquiring the water pressure and the membrane flux in real time in the positive flushing process, and judging whether the water pressure and the membrane flux reach a threshold value or not;

step 3.3, back flushing or restarting water purification:

if the step 3.2 judges that the water pressure and the membrane flux reach the preset threshold values, properly adjusting the flushing time of the positive flushing, and then repeating the step 3.2; if the water pressure and the membrane flux still reach or exceed the preset threshold after the set positive flushing times, starting a backwash pump (23) to pump produced water from the clean water tank (8) for backwash; if the water pressure and the membrane flux are smaller than the preset threshold value within the set positive flushing times, starting a water producing water pump (20) and restarting purifying the raw water;

step 3.5, stopping back flushing or restarting water purification:

if the step 3.4 judges that the water pressure and the membrane flux both reach the preset threshold values, the flushing time of back flushing is properly adjusted, and then the step 3.4 is repeated; if the water pressure and the membrane flux still reach or exceed the preset threshold after the set backwashing times, an alarm system is immediately triggered to stop backwashing; if the water pressure and the membrane flux are smaller than the preset threshold value within the set backwashing times, starting a water producing water pump (20) and restarting purifying the raw water;

in the process of restarting purifying raw water, monitoring and acquiring the produced water turbidity in real time through a produced water turbidity meter (22), and immediately triggering an alarm system to stop the operation of the underground membrane self-cleaning sewage treatment system if the monitored produced water turbidity reaches the threshold value preset in the step 2.4.1; if the monitored turbidity of the produced water does not reach the preset threshold value, the produced water is continuously extracted through the produced water outlet pump (20).

8. The method for treating sewage by self-cleaning the underground membrane according to claim 7, wherein the step 3.2 specifically comprises the following steps:

step 3.2.1, monitoring and acquiring water pressure in real time through a positive flushing pressure sensor (17) in the positive flushing process;

step 3.2.2, obtaining the water flow in unit time through a positive flushing flowmeter (16) in the positive flushing process;

step 3.2.3, calculating and obtaining total water flow in a sampling time period according to the water flow obtained in the step 3.2.2, and calculating and obtaining membrane flux according to the water flow;

9. The method for treating sewage by self-cleaning the underground membrane according to claim 7, wherein the step 3.4 specifically comprises the following steps:

step 3.4.1, monitoring and acquiring water pressure in real time through a back flush pressure sensor (25) in the back flush process;

step 3.4.2, obtaining the water flow in unit time through a backwash flowmeter (24) in the backwash process;

Step 3.4.3, calculating and obtaining total water flow in a sampling time period according to the water flow obtained in the step 3.4.2, and calculating and obtaining membrane flux according to the water flow;

10. The water purifying device is characterized by comprising a water purifying cylinder (401), wherein a main rotating shaft (402) is arranged at the center of the inside of the water purifying cylinder (401) along the axial direction, and a plurality of water purifying diaphragms (403) are fixedly and rotatably arranged on the main rotating shaft (402); a motor support plate (404) is fixedly arranged at the top end of the water purifying barrel (401), a motor (405) and a gear box (406) are fixedly arranged on the top surface of the motor support plate (404), a first gear (407) and a second gear (408) which are meshed with each other are arranged on the gear box (406), the first gear (407) is connected with the motor (405), the second gear (408) is arranged at the top end of the main rotating shaft (402), and the motor (405) drives the main rotating shaft (402) and the water purifying membrane (403) to rotate by driving the first gear (407) and the second gear (408);

a plurality of spray pipes (411) positioned in the same horizontal plane are uniformly distributed along the circumferential direction, a plurality of water purifying films (403) positioned in the same horizontal plane are uniformly distributed along the circumferential direction, a plurality of spray pipes (411) positioned in the same vertical plane are staggered with the plurality of water purifying films (403), a plurality of nozzles on the spray pipes (411) are divided into two rows, the two rows of nozzles are respectively positioned on the upper side and the lower side of the spray pipes (411) and are symmetrically arranged, and the water outlet direction of the nozzles faces the water purifying films (403);

the water purification device is characterized in that a plurality of membrane installation shafts (412) are rotatably installed on the main rotating shaft (402), a membrane installation frame (413) is fixedly connected to the membrane installation shafts (412), a water purification membrane (403) is fixedly installed in the membrane installation frame (413), a membrane support tube (414) is fixedly installed in the membrane installation frame (413) on the back side of the water purification membrane (403), and membrane fixing pieces (415) are installed on the membrane installation frames (413) on the inner side and the outer side of the water purification membrane (403).