CN113998811A

CN113998811A - Drinking water defluorination processing system

Info

Publication number: CN113998811A
Application number: CN202111194288.7A
Authority: CN
Inventors: 曾锐; 丘鸿斌; 李东红; 王瑞侠; 袁华
Original assignee: Zhongke Rinland Environmental Protection Technology Beijing Co ltd
Current assignee: Zhongke Rinland Environmental Protection Technology Beijing Co ltd
Priority date: 2021-10-13
Filing date: 2021-10-13
Publication date: 2022-02-01

Abstract

The invention provides a drinking water defluorination treatment system. The system comprises: a defluorination medicament adding device, a pipeline mixing device, a membrane filtering device and a central control device; the fluorine-removing agent adding device is used for adding a fluorine-removing agent into the raw water inlet pipeline; the water inlet end of the pipeline mixing device is connected with the water outlet of the raw water; the membrane filtering device is used for carrying out turbidity treatment on the water body flowing out of the pipeline mixing device; and the central control device is used for controlling the operation of the whole system, monitoring the fluorine content of the produced water in the water production side of the membrane filtering device and regulating and controlling the fluorine removal agent adding amount of the fluorine removal agent adding device according to the fluorine content. The system is simple to operate, high in water production rate, low in operation cost, high in water production qualification rate and convenient to use, and meanwhile, parameters of the reagent metering pump can be adjusted according to the local fluorine content, the reagent adding amount is changed, and the water quality after fluorine removal can reach the national sanitary standard for drinking water.

Description

Drinking water defluorination processing system

Technical Field

The invention relates to the technical field of drinking water treatment, and mainly relates to a drinking water defluorination treatment system.

Background

The concentration of fluoride in domestic drinking water is regulated to be not more than 1.0mg/L by the national sanitary Standard for domestic Drinking Water GB5749-2006, and the proper fluorine content in the drinking water is generally considered to be 0.5-1.0 mg/L. Nearly one hundred million people live in high fluorine areas in China, fluorine victims can reach tens of millions of people, and the fluorine intake mainly comes from drinking water. At present, in drinking water sources in many areas at home and abroad, the fluoride content exceeds the health standard, the highest fluoride content even exceeds the health standard by dozens of times, and the defluorination of drinking water is closely related to the health of people, so that great demand exists for the defluorination of drinking water.

However, the existing mainstream fluorine removal equipment mainly comprises a membrane method and an adsorption method, the membrane method fluorine removal equipment generally has the problems of large power consumption, low water yield and serious water resource waste, the adsorption method fluorine removal equipment has the problems of shorter and shorter regeneration period, frequent regeneration operation and large labor cost consumption, and simultaneously, the phenomenon of water outlet pause or unqualified outlet fluorine can be caused in the saturated regeneration stage of the fluorine removal filter material, namely the qualified rate of water quality can not reach 100 percent, the regeneration process can also generate fluorine-containing wastewater with high pH value and high concentration, the wastewater treatment operation is complex, the full-automatic operation or remote control is difficult to realize, and the total operation cost is higher.

Disclosure of Invention

In order to solve the difficult problems in the prior art, the invention designs a defluorinating agent adding device and a membrane filtering device which can perform synergistic action in the system so as to perform timely online pollution discharge and interception on floccules generated by online adding of the defluorinating agent, and simultaneously designs a central controller so as to perform full-automatic control on the whole system. The specific contents are as follows:

the invention provides a drinking water defluorination treatment system, which comprises: a defluorination medicament adding device, a pipeline mixing device, a membrane filtering device and a central control device;

the fluorine-removing agent adding device is used for adding a fluorine-removing agent into the raw water inlet pipeline;

the water inlet end of the pipeline mixing device is connected with the water outlet of raw water, and the raw water and the defluorination agent are mixed in the pipeline mixing device;

the membrane filtering device is used for carrying out turbidity treatment on the water body flowing out of the pipeline mixing device so as to obtain produced water meeting the water quality requirement;

the central control device is used for controlling the operation of the whole system, monitoring the fluorine content of the produced water in the water producing side of the membrane filtering device, and regulating and controlling the fluorine removal agent adding amount of the fluorine removal agent adding device according to the fluorine content.

Optionally, the membrane filtration device comprises a self-cleaning filter with a filter screen pore size of 100-200 microns and a membrane filter with a filter membrane pore size of 0.001-0.1 microns;

the water inlet end of the self-cleaning filter is connected with the water outlet end of the pipeline mixing device in series, and the water outlet end of the self-cleaning filter is connected with the water inlet end of the membrane filter in series;

the self-cleaning filter is used for carrying out primary turbidity interception treatment on a water body flowing in and automatically cleaning a filter screen according to the pressure difference of water flowing in and out of the self-cleaning filter;

the membrane filter is used for carrying out secondary turbidity interception treatment on the water body which flows in and is subjected to primary purification by the self-cleaning filter.

Optionally, a first drain outlet is arranged on the self-cleaning filter; and the first drain port is used for periodically draining the wastewater containing the filtered sediments and intercepted by the self-cleaning filter.

Optionally, the system further comprises a backwashing device; the flushing port of the backwashing device is arranged at the upper part of the water producing side of the filtering membrane;

the backwashing device is used for backwashing the filtering membrane from the upper part to the lower part of the filtering membrane and from the water production side to the water inlet side of the filtering membrane.

The backwashing device comprises a backwashing assembly;

the backwash assembly comprises: a backwashing water tank, a backwashing water pump and a backwashing water inlet pipe; the backwashing water pump is connected in series and arranged on the backwashing water inlet pipe; one end of the backwashing water inlet pipe is communicated with the backwashing water tank, and the outlet of the other end of the backwashing water inlet pipe is used as the flushing port arranged at the upper part of the water producing side of the filtering membrane.

The system also includes a gas wash device; and the air inlet of the air washing device is arranged at the lower part of the water inlet side of the filtering membrane.

Optionally, the gas-washing device (7) comprises a gas-washing assembly;

the air washing component comprises a vortex air pump, an air outlet of the vortex air pump is used as the air inlet and is arranged at the lower part of the water inlet side of the filtering membrane;

optionally, the system further comprises a drug washing device; the medicine inlet of the medicine washing device is arranged at the lower part of the water inlet side of the filtering membrane.

Optionally, the drug washing device comprises a drug washing assembly comprising: a medicament box, a medicament feeding pump and a medicament inlet pipe; the medicament feeding pump is arranged on the medicament inlet pipe in series; one end of the medicine inlet pipe is communicated with the chemical box, and the outlet of the other end of the medicine inlet pipe is used as the medicine washing inlet and is arranged at the lower part of the water inlet side of the filtering membrane.

Optionally, a second sewage draining outlet is arranged on the membrane filter; the second sewage draining outlet is arranged on the water producing side of the membrane filter, which is close to the filtering membrane, and is used for discharging the waste water which is intercepted by the filtering membrane and contains the filtering sediment and discharging the waste water which is subjected to gas washing and/or medicine washing.

Optionally, a third sewage draining outlet is arranged on the membrane filter; the third drain outlet is arranged on the water inlet side of the membrane filter and discharges the backwashing wastewater.

Optionally, the system further comprises a sewage treatment device; the sewage treatment device is used for receiving the wastewater discharged by each sewage discharge outlet and carrying out precipitation or/and filtration treatment on the wastewater.

Optionally, the fluorine removal agent dosing device comprises: a defluorination medicament box, a defluorination medicament adding pump and a defluorination medicament inlet pipe;

the outlet of the defluorination medicament box is connected with one end of the defluorination medicament inlet pipe, the other end of the defluorination medicament inlet pipe is connected with the pipeline mixing device, and the defluorination medicament feeding pump is installed on the defluorination medicament inlet pipe in series;

the defluorination agent in the defluorination agent box enters the pipeline mixing device through the defluorination agent feeding pipe under the action of the defluorination agent feeding pump and is mixed with raw water in the pipeline mixing device.

Optionally, the central control apparatus comprises a defluorination agent control module;

the defluorination agent control module is used for controlling the defluorination agent adding device, and

the fluorine content of the produced water in the water producing side of the membrane filtering device is monitored, and the fluorine removal agent adding amount of the fluorine removal agent adding device is regulated and controlled according to the fluorine content.

Optionally, the central control device further comprises a flushing control module; the flushing control module is used for monitoring the water inlet and outlet pressure difference of the filtering membrane and controlling whether to start the backwashing device, the air washing device or the medicine washing device and/or start the backwashing device, the air washing device or the medicine washing device according to the water inlet and outlet pressure difference

And the device is used for monitoring the working time of the filtering membrane and controlling whether to start the backwashing device, the gas washing device or the medicine washing device according to the time period of the working time.

Optionally, the central control device further includes an electric control device, and the system integrally controls the opening or closing of all the electric valves in the system through the electric control device.

The invention provides a drinking water defluorination treatment system. The system comprises: a defluorination medicament adding device, a pipeline mixing device, a membrane filtering device and a central control device; the fluorine-removing agent adding device is used for adding a fluorine-removing agent into the raw water inlet pipeline; the water inlet end of the pipeline mixing device is connected with the water outlet of the raw water, and the raw water and the defluorination agent are mixed in the pipeline mixing device; the membrane filtering device is used for carrying out turbidity treatment on the water body flowing out of the pipeline mixing device; and the central control device is used for controlling the operation of the whole system, monitoring the fluorine content of the produced water in the water production side of the membrane filtering device and regulating and controlling the fluorine removal agent adding amount of the fluorine removal agent adding device according to the fluorine content. The system is simple to operate, high in water production rate, low in operation cost, high in water production qualification rate and convenient to use, and meanwhile, parameters of the reagent metering pump can be adjusted according to the local fluorine content, the reagent adding amount is changed, and the water quality after fluorine removal can reach the national sanitary standard for drinking water.

Compared with the prior art, the system provided by the invention is a treatment system combining integrated defluorination agent and membrane filtration, can be used in high/medium/low fluorine-containing areas, has a wide application range, can stably remove fluorine for a long time, can realize full-automatic operation and remote control, has a simple operation method, short reaction time, low operation cost and stable defluorination effect, and can detect the concentration of fluorine ions in produced water on line. The water yield of the whole treatment system is more than or equal to 95 percent. The method comprises the following specific steps:

1. according to the system provided by the invention, the generated floccule is removed by utilizing the effect of removing turbidity through membrane filtration, so that the used filtration pore size (which can be the filtration pore size of a self-cleaning filter and can be the membrane pore size of a filtration membrane in the membrane filter) is relatively large, so that based on large-pore-size filtration, the energy consumption in an actual system is greatly saved (specifically, the energy consumption can be reduced to 20-30% of the original energy consumption), meanwhile, the water quality qualification rate can reach 100% and the water yield is high, and the problems of water waste, high energy consumption and easy pollution and blockage in the existing membrane method are avoided.

2. In the system provided by the invention, the adopted membrane filter is of an external pressure type, the middle cavity is large, pollutants such as floccules and the like intercepted on the filtering membrane inside are easy to wash away, membrane pollution is not easy to form, membrane fouling is not easy to cause, the service life of the filtering membrane is prolonged, the replacement frequency of the filtering membrane is reduced, and meanwhile, the aperture of the filtering membrane is moderate, so that the membrane flux is large, the water flux of the membrane is high during operation, the raw water with the same volume is treated, the membrane area of the filtering membrane is correspondingly reduced, and the equipment investment and the operation cost are reduced.

3. The method of adding the defluorinating agent on line is adopted, so that the coagulating sedimentation process based on a coagulating basin is omitted, the system flow is shortened, the equipment investment cost is reduced, the retention time consumed by coagulating sedimentation is saved, and the treatment efficiency is improved. Meanwhile, based on the combination of the filtering membrane with the proper aperture and the online feeding, the raw water pressure can be utilized to enable the water body to automatically pass through the filtering membrane, so that the pressure relief and the required secondary pressurization operation caused by the coagulation sedimentation based on the coagulation tank are avoided, the energy consumption is greatly reduced, and the investment cost of a pressurization device is also saved.

4. Because the system discharges and intercepts the floccule, the discharged wastewater does not contain high fluorine and high alkali, and some wastewater only contains turbidity caused by floccule (the turbidity can be removed by a simple treatment system in the wastewater treatment process, such as filtration or precipitation), so the system also has the advantage of relatively easy wastewater treatment process.

5. On one hand, compared with the adsorption method for removing fluorine, the system has the advantages of high qualified rate of produced water, convenience in operation, no need of much labor, capability of realizing full-automatic operation or remote control, low overall treatment cost and the like; on the other hand, compared with the fluorine removal by a nanofiltration or reverse osmosis membrane method, the system has the advantages of extremely low energy consumption, water production rate of over 95 percent, water resource saving, low wastewater rate, easy treatment, difficult blockage of the filter membrane, good performance recovery after cleaning, long service life, low treatment cost and the like, and simultaneously, the produced water has better retention of mineral elements beneficial to human bodies. Therefore, the system can effectively avoid the defects of the two conventional mainstream fluorine removal methods, and simultaneously, the long-flow treatment system is changed into the short-flow treatment system in an online feeding mode, so that the problem of high energy consumption caused by a coagulating sedimentation method is solved.

Drawings

FIG. 1 shows a schematic diagram of a drinking water defluorination treatment system in an embodiment of the present invention;

FIG. 2 shows a schematic diagram of another drinking water defluorination treatment system in an embodiment of the present invention;

fig. 3 shows a schematic diagram of the relationship between the water flow direction of the filtering membrane and the flushing direction of the backwashing in the embodiment.

Detailed Description

The following examples are provided to further understand the present invention, not to limit the scope of the present invention, but to provide the best mode, not to limit the content and the protection scope of the present invention, and any product similar or similar to the present invention, which is obtained by combining the present invention with other prior art features, falls within the protection scope of the present invention.

An embodiment of the present invention provides a drinking water defluorination treatment system, as shown in fig. 1, the system includes: a fluorine removal agent adding device 1, a pipeline mixing device 2, a membrane filtering device 3 and a central control device 4;

the fluorine removal agent adding device 1 is used for adding a fluorine removal agent into a raw water inlet pipeline;

the water inlet end of the pipeline mixing device 2 is connected with the water outlet of the raw water, and the raw water and the fluorine removal agent are fully mixed in the pipeline mixing device 2, so that the fluorine removal agent can completely react with fluorine in the raw water to generate a flocculent complex;

the membrane filtering device 3 is used for carrying out turbidity treatment on the water flowing out of the pipeline mixing device 2 so as to obtain produced water meeting the water quality requirement;

the central control device 4 is used for controlling the operation of the whole system, monitoring the fluorine content of the produced water in the water producing side of the membrane filtering device 3, and regulating and controlling the fluorine removal agent adding amount of the fluorine removal agent adding device 1 according to the fluorine content. Wherein, the central control device 4 monitors the fluorine content in the produced water through the on-line monitoring module 4-1.

The system provided by the embodiment is used as an integrated device, and the adding amount of the fluorine removal agent is monitored and controlled on line in real time through the central control module 4, so that the fluorine treatment operation in the prior art can be simplified; the combined device for adding the medicament on line and filtering turbidity through membrane filtration can ensure the water yield and the qualified rate of the produced water, simplify the operation, reduce the operation cost and improve the use convenience of the system; meanwhile, full-automatic operation and remote control can be realized based on the central control module 4, parameters of a reagent metering pump are adjusted according to the local fluorine content, the adding amount of the reagent is changed, and the water quality after fluorine removal can reach the national sanitary standard for drinking water. Therefore, the system provided by the embodiment can stably remove fluorine for a long time, can realize full-automatic operation and remote control, has simple operation method, short reaction time, low operation cost and stable fluorine removal effect, and can detect the concentration of fluorine ions in produced water on line.

In another embodiment of the present invention, as shown in fig. 2, optionally, the membrane filtration device 3 comprises a self-cleaning filter 3-1 with a filter mesh pore size of 100 micrometers to 200 micrometers, and a membrane filter 3-2 with a filter membrane pore size of 0.001 micrometers to 0.1 micrometers;

In the embodiment, the membrane filtering device 3 is installed in series after the pipeline mixer 2 and comprises a self-cleaning filter 3-1 and a membrane filter 3-2, and the water inlet end of the membrane filter 3-2 is connected in series with the water production end of the self-cleaning filter 3-1.

The self-cleaning filter 3-1 is provided with a first drain outlet 3-11; the first drain outlet 3-11 is communicated with a drain pipe 3-12 and is used for periodically discharging the wastewater containing the filtered sediments and intercepted by the self-cleaning filter. The self-cleaning filter 3-1 can also carry out full-automatic cleaning on the filter screen according to the water inlet and outlet pressure difference of the self-cleaning filter 3-1, and the water inlet valve at the water inlet end is not required to be closed during automatic cleaning.

The filtering membrane 3-22 in the membrane filter 3-2 is a nanofiltration membrane or/and an ultrafiltration membrane, and can also be a combination of a nanofiltration membrane or an ultrafiltration membrane and other filtering membranes. The membrane filter 3-2 is connected with a water production pipe for leading out the purified water. The concentrated water end of the filtering membrane 3-22 is provided with a second sewage draining port 3-24 for continuously draining the wastewater containing the filtering sediments intercepted by the filtering membrane 3-22 from the second sewage draining port 3-24 through a wastewater draining pipe 3-23.

The water production end of the membrane filter 3-2 is connected with the online monitoring module 4-1, the online monitoring module 4-1 is used for online monitoring of fluorine ions in the produced water, and monitored data are transmitted back to the central control device 4 for calculation and processing of the central control device 4.

In the embodiment, the defluorination agent and raw water are mixed and reacted and then enter the self-cleaning filter for first filtration, the filtered precipitate is discharged through a sewage discharge pipeline, and the filtrate enters a membrane filtration device connected with the self-cleaning filter in series; the water production section of the filter membrane device is connected with an online fluorine ion content monitoring device, the fluorine concentration of the produced water can be monitored online in real time, if the fluorine content of the drinking water exceeds the requirement, the relevant parameters of the defluorinating agent metering pump can be adjusted on site or remotely, and the adding amount of the agent is changed until the fluorine of the produced water is qualified.

In another embodiment of the present invention, as shown in fig. 2, optionally, the system further comprises a backwashing device 6; the flushing port of the backwashing device 6 is arranged at the upper part of the water producing side of the filtering membranes 3-22;

the back washing device 6 is used for back washing the silts intercepted on the filtering membranes 3-22 from the upper part to the lower part of the filtering membranes and from the produced water side of the filtering membranes 3-22 to the water inlet side.

Wherein the wastewater after backwashing can be continuously discharged from the second sewage discharge port 3-24 and/or the third sewage discharge port 3-21 through the wastewater discharge pipe 3-23.

In particular implementation, the backwashing means 6 optionally comprise a backwashing assembly arranged at the upper part of the membrane filter for saving space during installation and for flushing the filtration membranes 3-22 from the upper part of the water production side of the filtration membranes 3-22. In practical application, the backwashing component can be a pure water backwashing component. Specifically, the pure water backwash assembly includes: backwash pure water tank, backwash water pump and backwash inlet tube. The backwashing water pump is connected in series with the backwashing water inlet pipe, one end of the backwashing water inlet pipe is communicated with the backwashing pure water tank, and the outlet of the other end is arranged at the upper part of the water producing side of the filtering membranes 3-22 as a flushing port.

The operation of the backwashing device 6 is as follows: when the system runs for a period of time, the filtering membranes 3-22 can form certain dirt blockage, then the central control device 4 automatically induces the water inlet and outlet pressure difference of the filtering membranes 3-22, the back washing device 6 is started according to the water inlet and outlet pressure difference of the filtering membranes 3-22, under the action of the electric control device, the fluorine removal agent adding pump is closed, the water inlet valve on the water inlet pipe and the water outlet valve on the water production pipe are closed, the water inlet valve on the back washing water inlet pipe and the valve on the waste water discharge pipe are opened, and the back washing is carried out on the filtering membranes 3-22 through the back washing water inlet pipe. The back-flushed waste water is continuously discharged from the second drain outlet 3-24 and/or the third drain outlet 3-21 through the waste water discharge pipe 3-23.

FIG. 3 is a schematic diagram showing the relationship between the direction of water flow and the direction of backwashing of the filter membrane in the present embodiment. The backwash in this embodiment will be described in detail with reference to fig. 3. Specifically, the backwashing in this embodiment refers to: and backwashing the filtering membranes 3-22 in a direction opposite to the forward flow direction of the water body. For example, if the filtering membrane 3-22 of the membrane filter 3-2 is a cylindrical filtering membrane, the filtering membrane 3-22 is vertically placed, the water inlet is arranged at the bottom of the water inlet side of the filtering membrane 3-22, and the water producing port is arranged at the upper part of the water producing side of the filtering membrane 3-22, so that the water body is filtered from the filtering membrane 3-22 from the bottom to the top, then the filtering membrane 3-22 is backwashed from the upper part of the water producing side of the filtering membrane 3-22 from the top to the bottom and from the water producing side of the filtering membrane 3-22 to the water inlet side, so that the washed sludge flows out from the third sewage discharge port 3-21 of the sewage discharge channel at the water inlet side of the filtering membrane 3-22.

The system also comprises a gas washing device 7; the air inlet 3-26 of the air washing device 7 is arranged at the lower part of the water inlet side of the filtering membrane 3-22; and the air washing device 7 is used for carrying out air washing on the filtering membranes 3-22 from the bottom to the top and from the water inlet sides of the filtering membranes 3-22 on the silted matters intercepted on the filtering membranes 3-22.

Wherein the dirt washed by the gas is continuously discharged from the second sewage discharge outlet 3-24 through a sewage discharge pipe.

In practice, the air washing component of the air washing device 7 may optionally include a vortex pump. The air inlet is used as an air charging opening and is arranged at the lower part of the water inlet side of the filtering membranes 3-22.

The operation of the gas washing device 7 is: when the system runs for a period of time, the filtering membranes 3-22 can form certain dirt blockage, then the central control device 4 automatically induces the water inlet and outlet pressure difference of the filtering membranes 3-22, the gas washing device 7 is started according to the water inlet and outlet pressure difference of the filtering membranes 3-22, under the action of the electric control device, the defluorination agent adding pump is closed, the water inlet valve on the water inlet pipe and the water outlet valve on the water production pipe are closed, the valve on the air inlet pipe and the valve on the wastewater discharge pipe are opened, and the filtering membranes 3-22 are swept through the gas washing device 7.

The system also comprises a drug washing device 8; and the medicine washing device 8 is used for washing the filtering membranes 3-22 with medicine from bottom to bottom and from the water inlet sides of the filtering membranes 3-22 to thoroughly wash the membrane surfaces of the filtering membranes 3-22 and recover the membrane flux.

Wherein, the medicine washing device 8 is provided with a medicine washing component. The drug washing assembly comprises: a medicament box, a medicament adding pump and a medicament inlet pipe. The medicament adding pump is arranged on the medicament inlet pipe in series; one end of the medicine inlet pipe is communicated with the medicine box, and the outlet of the other end is used as a medicine washing inlet 3-25 and is arranged at the lower part of the water inlet side of the filtering membrane 3-22. The sewage after the drug washing is also continuously discharged from the second sewage discharge outlet 3-24 through a sewage discharge pipe.

In order to make the skilled person better understand the washing operation of the filtering membranes 3-22 in the present application, the applicant takes the combined assembly of the backwashing assembly, the gas washing assembly and the drug washing assembly as an example to explain the function of the backwashing device 6, the function of the gas washing device 7 and the function of the drug washing device 8. The method specifically comprises the following steps: when the system runs for a period of time, the filtering membranes 3-22 can form certain dirt blockage, then the central control device 4 automatically induces the water inlet and outlet pressure difference of the filtering membranes 3-22, the back washing device 6 is started according to the water inlet and outlet pressure difference of the filtering membranes 3-22, under the action of the electric control device, the fluorine removal agent adding pump is closed, the water inlet valve on the water inlet pipe and the water outlet valve on the water production pipe are closed, the water inlet valve on the back washing water inlet pipe and the valve on the waste water discharge pipe are opened, and the filtering membranes 3-22 are washed through the back washing water inlet pipe; after washing, carrying out air washing, wherein the air washing is to blow, oscillate and impact the sediment on the surfaces of the filtering membranes 3-22 through a vortex air pump so that the sediment trapped on the filtering membranes 3-22 falls down and is discharged with backwash liquid; after air washing, medicine washing is continuously carried out, and the medicine washing is to dissolve the sediment in water to be peeled off from the filtering membranes 3-22 through the reaction of the medicine and the blocking sediment on the filtering membranes 3-22, so as to recover the flux of the filtering membranes.

It should be noted that the above-mentioned washing operation is water washing, then air washing, and finally drug washing. In the actual operation process, the following steps can be performed: air washing, medicine washing and water washing. The specific sequence can be adjusted according to requirements.

In this embodiment, one of the backwashing devices 6, the gas washing device 7, and the medicine washing device 8 may be selected for washing, or two or three of them may be selected for washing.

Among them, it should be noted that: in the system provided by the embodiment, the water inlets, the medicine inlets and the water outlets of all the components are respectively communicated through connecting pipes and controlled by one-way electric valves, and the central control device further comprises an electric control device which is in communication connection with all the electric valves in the system. The system integrally controls the opening or closing of all electric valves in the system through an electric control device.

In this embodiment, optionally, the central control device 4 further includes a flushing control module. And the flushing control module is used for monitoring the water inlet and outlet pressure difference of the filtering membranes 3-22, controlling whether to start the backwashing device 6, the air washing device 7 or the medicine washing device 8 according to the water inlet and outlet pressure difference, and/or monitoring the working time of the filtering membranes 3-22, and controlling whether to start the backwashing device 6, the air washing device 7 or the medicine washing device 8 according to the time period of the working time.

Wherein, the flushing control module comprises a back flushing control module, a gas washing control module and a medicine washing control module. And the backwashing control module is used for monitoring the water inlet and outlet pressure difference of the filtering membranes 3-22 and controlling whether to start the backwashing device 6 according to the water inlet and outlet pressure difference, and/or monitoring the working time of the filtering membranes 3-22 and controlling whether to start the backwashing device 6 according to the time period of the working time. The air washing control module is in communication connection with the air washing device 7 and is used for monitoring the water inlet and outlet pressure difference of the filtering membranes 3-22 and controlling whether to start the air washing device 7 according to the water inlet and outlet pressure difference and/or monitoring the working time of the filtering membranes 3-22 and controlling whether to start the air washing device 7 according to the time period of the working time. The drug washing control module is in communication connection with the drug washing device 8 and is used for monitoring the water inlet and outlet pressure difference of the filtering membranes 3-22 and controlling whether to start the drug washing device 8 according to the water inlet and outlet pressure difference and/or monitoring the working time of the filtering membranes 3-22 and controlling whether to start the drug washing device 8 according to the time period of the working time.

In this embodiment, optionally, the system further includes a sewage treatment device 5; and the sewage treatment device 5 is used for receiving the wastewater discharged by the first sewage discharge port, the second sewage discharge port and the third sewage discharge port and carrying out precipitation or/and filtration treatment on the wastewater.

In this embodiment, optionally, the fluorine-removing agent adding apparatus 1 includes: a defluorination medicament box, a defluorination medicament adding pump and a defluorination medicament inlet pipe;

the outlet of the defluorination medicament box is connected with one end of the defluorination medicament inlet pipe, the other end of the defluorination medicament inlet pipe is connected with the pipeline mixing device 2, and the defluorination medicament feeding pump is installed on the defluorination medicament inlet pipe in series;

the defluorination agent in the defluorination agent box enters the pipeline mixing device 2 through the defluorination agent feeding pipe under the action of the defluorination agent feeding pump and is mixed with raw water in the pipeline mixing device 2.

In specific implementation, the defluorination medicament feeding pipe is connected to the defluorination medicament box, and the defluorination medicament feeding pump is installed on the defluorination medicament feeding pipe in series; the water inlet end of the pipeline mixer 2 is connected with a raw water outlet, a raw water inlet pipeline is connected with a defluorination medicament dosing pipe, and raw water and medicament are mixed in the pipeline mixer.

In this embodiment, optionally, the central control device 4 further includes a defluorination agent control module;

and the defluorination agent control module is used for controlling the defluorination agent adding device 1 and monitoring the fluorine content of the produced water in the water producing side of the membrane filtering device 3, and regulating and controlling the defluorination agent adding amount of the defluorination agent adding device according to the fluorine content.

In this embodiment, the system provided by this embodiment can be installed in a container, and the container is externally arranged with a water inlet main pipe, a water production main pipe, a defluorination agent inlet main pipe, a backwashing main pipe, a chemical washing main pipe and a discharge main pipe. The water inlet main pipe is connected with the water inlet end of the pipeline mixing device 2, so that raw water can enter the pipeline mixing device 2 through the water inlet main pipe; the water production mother pipe is connected with the water production pipe of the membrane filter 3-2, so that the treated water meeting the water quality requirement can be directly output to each use point; the defluorination medicament mother pipe is connected with the defluorination medicament box, so that the defluorination medicament in the defluorination medicament box can be supplied in time after being used up; the backwashing main pipe is connected with the backwashing water tank so that backwashing water in the backwashing water tank can be supplied in time after the backwashing water is used up; the drug washing main pipe is connected with the drug box, so that the drug in the drug box can be supplied in time after being used up; the main discharge pipe is connected with a sewage treatment device, so that the sewage treatment device can output the treated water in time after the sewage treatment. Thus, when the system provided by the embodiment is installed in a container, the system can be communicated with the outside through the main pipes, so that raw water, fluorine removal agents, backwashing water and cleaning agents can be timely conveyed to corresponding points in the system from the outside in the long-term operation process of the system, and the produced water and the treated sewage in the system can be smoothly output in time, thereby realizing the long-term operation of the system. Therefore, the system that this embodiment provided both can realize carrying conveniently based on the container, can realize the normal start and the long-term operation of system based on these female pipes again.

In order to enable a person skilled in the art to better understand the system provided by the embodiment of the present invention, the applicant explains the operation of the system provided by the embodiment of the present invention in detail. The method comprises the following specific steps:

first, the system provided in this embodiment can be started by the general control button on the central control device 4. Specifically, the method comprises the following steps: when a master control button is pressed, raw water is sent into a pipeline mixer, a defluorinating agent adding pump is automatically started, the raw water and the defluorinating agent added through a defluorinating agent adding pipe are fully mixed and reacted in the pipeline mixer according to a preset flow proportion through a water inlet pipe, when water enters a membrane filter 3-2 and is full of a membrane cavity, the whole system enters normal operation, flocculation precipitates, other suspended matters, microorganisms, certain metal elements and the like in the water body after being intercepted by filtering membranes in a self-cleaning filter 3-1 and the membrane filter 3-2 flow out from a sewage discharge port, so that fluorine ions in the water body are removed, and the concentration of fluorine ions in produced water reaches the national sanitary standard for drinking water.

Then, a filter screen is arranged in the self-cleaning filter 3-1, and flocculent precipitate formed after the fluorine removal medicament reacts with the raw water and other suspended matters in the water body can be filtered. When the system runs for a period of time, a certain pressure difference is generated between the water inlet and the water outlet of the self-cleaning filter 3-1, when the pressure difference value is larger than or equal to a set value, the motor of the filter 3-1 is started, the discharge valve is opened, and self-cleaning is started.

After the system runs for a period of time, the filtering membranes 3-22 form certain dirt blockage, then the central control device 4 automatically induces the water inlet and outlet pressure difference of the filtering membranes 3-22, the backwashing device 6 is started according to the water inlet and outlet pressure difference of the filtering membranes 3-22, under the action of the electric control device, the defluorination agent adding pump is closed, the water inlet valve on the water inlet pipe and the water outlet valve on the water production pipe are closed, the water inlet valve on the backwashing water inlet pipe and the valve on the wastewater discharge pipe are opened, and the filtering membranes 3-22 are washed through the backwashing water inlet pipe; after washing, carrying out air washing, wherein the air washing is to blow, oscillate and impact the sediment on the surfaces of the filtering membranes 3-22 through a vortex air pump so that the sediment trapped on the filtering membranes 3-22 falls down and is discharged with backwash liquid; after air washing, the medicine washing is continued, and the medicine washing is to dissolve the sediment in the water to be peeled off from the filtering membranes 3-22 by the reaction of the medicine and the blocking sediment on the filtering membranes 3-22, so that the flux of the membranes is recovered.

And then, an online monitoring module 4-1 which is installed on the water production pipe in series monitors the water production flow on one hand and the fluorine ion content in the water production on the other hand, and respectively sends the detection results to a flushing control module and a fluorine removal agent control module of the central control device 4. The defluorination agent control module regulates and controls the dosage of the defluorination agent dosage device 1 according to the content of the received fluorine ions. And the flushing control module controls whether to start the backwashing device 6, the gas washing device 7 and the medicine washing device 8 or not according to the received produced water flow or the inlet and outlet water pressure difference of the filtering membrane, and flushes the filtering membrane at regular time, so that the dosage of the defluorination medicine and the flushing program are remotely controlled in real time.

In addition, the flushing control module can be used for starting any one of the backwashing device 6, the air washing device 7 and the medicine washing device 8 according to the accumulated value of the amount of the treated water, for example, when the accumulated amount reaches a certain value, so as to flush the filtering membrane in the membrane filter.

In the embodiment, the filtering aperture of the filtering membrane is less than or equal to 0.1 micron, flocculent precipitate, macromolecular organic matter, water suspended matter and partial metal elements can be filtered, the turbidity of the outlet water is stable below 0.1NUT, the membrane service life can be prolonged by the flushing operation, the total water yield is improved, and the replacement cost of the membrane is reduced.

In this embodiment, the membrane filter 3-2 includes a plurality of ultrafiltration membrane modules arranged in a line and connected in parallel, and the water inlets, the produced water outlets, and the concentrated water outlets of all the ultrafiltration membrane modules in the membrane filter 3-2 are respectively communicated together by connecting pipes to form a water inlet end, a water production end, and a concentrated water end of the membrane filter 3-2.

In this embodiment, the inlets and outlets of all the connecting pipes are provided with one-way electric valves, and are controlled by the electric control device in a unified manner.

The fluorine removal treatment system provided by the embodiment of the invention is a composite drinking water fluorine removal treatment system, adopts a fluorine removal medicament for pretreatment, converts fluorine in raw water into a complex, traps coagulating sedimentation (formed on the basis of the complex) in water through a self-cleaning filter, and finally filters through a filter membrane to stabilize the turbidity of produced water below 0.1NTU so as to realize the purpose of indirectly removing the fluorine in the raw water.

The system provided by the embodiment of the invention can be used for real-time online monitoring, and the dosage of the dosing agent is adjusted according to the water inlet amount or the fluorine content of the produced water, so that the fluorine content of the produced water is qualified.

In the practical implementation process, after the fluorine removal agent is added into the raw water, the fluorine removal agent is automatically and uniformly mixed with the raw water under the action of the water flow of the raw water and fully reacts with fluorine in the raw water to generate a complex and form floccule, and then the water containing the floccule continuously passes through the self-cleaning filter and the membrane filter in sequence under the action of the water pressure of the raw water. That is to say, in this embodiment, after adding raw water, the defluorination agent enters the filtration process after being mixed in the pipeline, the whole system is continuously and automatically operated, and the pressure is not released in the middle link, and secondary pressurization is not needed, so the energy consumption is low, and the equipment investment is low.

In practical implementation, optionally, the fluorine removal agent is an aluminum salt aqueous solution; wherein the mass percentage of the aluminum salt in the aluminum salt aqueous solution is 25-50%. Preferably, the aluminum salt in the aluminum salt aqueous solution is polyaluminum chloride and/or aluminum sulfate.

In specific implementation, the fluorine removal agent comprises one or two mixtures of polyaluminium chloride and aluminum sulfate, namely, the aluminum salt aqueous solution can contain other components besides aluminum salt and water so as to achieve other purposes.

The online feeding is as follows: the method has the advantages that the medicament is directly added into the raw water flowing on line, the raw water is not subjected to retention treatment, and the on-line system flow that the raw water directly reaches the drinking water standard after flowing on line is realized. Therefore, in order to realize online addition, the reagent can quickly react with ions in raw water after being added, and the characteristic that turbidity is easy to remove is required. Therefore, in this embodiment, the main effective component of the fluorine removal agent is polyaluminum chloride and/or aluminum sulfate.

The polyaluminium chloride or aluminium sulfate can quickly form a complex which is easy to intercept and discharge pollution with fluorine, so that the application scene of online feeding is met (in the continuous flow of raw water, the water flow flows fast under the action of pressure, if the reaction is slow, the water flow pressure of the raw water is combined, the water directly enters a water producing side before the reaction, so that a good removing effect cannot be achieved, and if the reaction is too slow, a sedimentation tank needs to be additionally arranged in the system flow, and a secondary pressurizing device is further additionally arranged on the basis of the addition of the sedimentation tank).

In actual operation, optionally, a mixing pipe is provided before the self-cleaning filter, and the fluorine-removing agent and the raw water flowing into the mixing pipe are mixed by the mixing pipe.

In the embodiment, in order to ensure that the fluorine removal agent and the fluorine in the raw water react sufficiently on the basis of on-line feeding, the applicant sets a mixing pipeline with a larger pipe diameter before the self-cleaning filter, wherein the pipe diameter of the mixing pipeline is larger than that of the water inlet pipeline, so that the water containing the fluorine removal agent can utilize the buffer action of flowing into the large pipe diameter from a small pipe diameter to realize the sufficient reaction of the fluorine removal agent and the fluorine, and further, the fluorine almost completely reacts with the fluorine removal agent to form floccule when the water body reaches the self-cleaning filter and the membrane filter. Then, the floccules are discharged along with respective sewage discharge ports of the self-cleaning filter and the membrane filter (3-5% of sewage discharge is reserved in the membrane filter in actual operation), and in addition, 95-97% of water body passes through a filtering membrane in the membrane filter and reaches a water production side.

That is to say, in this embodiment, the online feeding can be realized in this system because the reaction speed of the aluminum salt is fast enough, and accordingly, after the online feeding is realized, based on the operation characteristics of the online feeding, the whole system is simpler, more convenient, and easier to realize the automation of the equipment.

In actual implementation, the on-line dosage of the fluorine removal agent is determined according to the fluorine content in the water after being intercepted by the membrane filtration.

In this embodiment, since the fluorine removing agent contains a substance that reacts with fluorine, such as an aluminum salt polymer, if the fluorine removing agent is added in an excessive amount, there is a risk that the content of aluminum in water on the water producing side will be exceeded. Therefore, it is necessary to control the amount of the fluorine-removing agent to be added. Specifically, the requirement of national sanitary Standard for Drinking Water is taken as a reference, the preset value range of the fluorine content in the water intercepted by the membrane filtration method is preset to be 0.5-0.99 mg/L, the preferred preset value range is 0.8-0.9 mg/L, and the actual value in the water intercepted by the membrane filtration method meets the requirement of the preset value range by regulating and controlling the on-line addition of the fluorine removal agent.

In the actual application process, the initial adding amount of the fluorine removal agent can be determined through a laboratory experiment to determine the ratio of the fluorine content in the raw water to the initial adding amount, and then in the actual application process, the initial adding amount to be added can be determined directly according to the fluorine content in the raw water and the water inlet flow of the raw water.

In practical implementation, the diameter of the filter mesh in the self-cleaning filter is optionally 100-200 microns; that is, the self-cleaning filter selected in this embodiment has an interception accuracy of 100 microns to 200 microns to filter out suspended substances and colloids in water.

The aperture of a filtering membrane of the filtering membrane in the membrane filter is 0.001-0.1 micron, and suspended matters and partial metal ions in water are completely filtered by a high-precision filtering membrane (such as a nano-filtering membrane or an ultra-filtering membrane). It should be noted that: if the defluorination agent is selected from polyaluminium chloride and/or aluminium sulphate, if residual aluminium is not intercepted, the aluminium content on the water production side is easy to exceed the national standard of 0.2mg/L, therefore, the pore diameter of 0.001-0.1 micron is selected, on one hand, the turbidity of water is removed (namely, the smaller particle size in the water is removed), and on the other hand, the pore diameter is selected to intercept part of residual aluminium.

In this embodiment, adjust the input amount of defluorination agent through the fluorine content of real-time on-line monitoring raw water and product aquatic, including the dual filtration effect of filtration membrane, aluminium in the defluorination agent forms the floc with the fluorine in the raw water and discharges from sewage pipes, even there is very little remaining also can be held back by the filtration membrane most, and can not get into the product water side through the filtration membrane basically, has ensured that the residual aluminium of product water can not exceed the standard, and product water quality of water all reaches the requirement of national drinking water health standard. Meanwhile, the turbidity in the discharged sewage is a main unqualified item, and the discharged sewage can be treated to reach the standard by a simple precipitation and filtration method.

In the implementation step, the self-cleaning filter has the functions of: most of large-particle-size floccules are intercepted firstly, and then a small amount of small-particle-size floccules are reserved for the membrane filter to be intercepted, so that the intercepting workload of the membrane filter is relieved, the service life of the membrane filter is prolonged, the working time in the cycle is prolonged (because if a self-cleaning filter is not arranged, the membrane filter is more likely to cause membrane fouling due to more intercepted floccules), and the pollution degree of the membrane is reduced.

The embodiment of the invention adopts a system combining fluorine removal agent and filter membrane filtration, the agent is added on line, the adding amount of the agent is set according to the fluorine content of raw water, the raw water is mixed in a pipeline and then enters a filtration process, continuous automatic operation is realized, no pressure relief is generated in an intermediate link, the energy consumption is low, the equipment investment is low, the fluorine content of produced water is stable, the water production rate is high, the wastewater rate is low, no pollution is caused, repeated regeneration is not needed, and the fluorine content and the aluminum content in water can be strictly controlled by a fine online monitoring device and a dosing mode, so that the fluorine content and the aluminum residue in the final effluent meet the requirements of the national sanitary standard for drinking water, the long-term stable fluorine removal effect of the whole system is ensured, and the drinking water safety is ensured. The system is simple, the water production rate is up to more than 95 percent, no pressure relief is generated during the online addition of the medicament, the operation is simple, the full-automatic operation and remote control can be realized, the energy consumption and the treatment cost are low, the retention of mineral elements beneficial to human bodies in the produced water is better, the method is a brand new method of a drinking water defluorination treatment system, has extremely wide practical value, and must become a mainstream treatment system for the defluorination of future drinking water and even industrial water treatment.

In order to make the present invention better understood by those skilled in the art, the following examples are provided to illustrate the fluorine removal effect of the drinking water fluorine removal treatment system provided by the present invention when applied.

Example 1: the fluorine content of raw water is 2.0mg/L, and the drinking water defluorination treatment system provided by the invention adopts the following treatment steps:

(1) the flow rate of the inlet water is set to be 2 tons/hour, and the flow rate of the aluminum sulfate aqueous solution medicament is set to be 1.4 liters/hour;

(2) introducing DN50 into a pipeline mixer for mixing reaction, wherein the mixing time in the pipeline is about 5-10 seconds;

(3) the water after reaction passes through a self-cleaning filter of 200 microns, and flocculated precipitates are intercepted;

(4) the water after passing through the self-cleaning filter enters a nanofiltration membrane for filtering, the filtering aperture reaches 0.003 micron, meanwhile, the water-producing rate is 95 percent, the water after treatment also has a certain interception and removal effect on residual aluminum in the medicinal agent in the water body, and the water meets the requirements of the national sanitary Standard for Drinking Water;

(5) and flushing the filter membrane every 30-45 minutes for about 30-60 seconds each time.

Through the treatment, the fluorine content of the effluent is 0.6mg/L, the turbidity is less than 0.1NTU, the aluminum content is 0.115mg/L, and the requirements of corresponding indexes in the national sanitary Standard for Drinking Water are met.

Example 2, the fluorine content of the raw water is 3.0mg/L, and based on the drinking water fluorine removal treatment system provided by the invention, the following treatment steps are adopted:

(1) the flow rate of water inlet is set to be 2 tons/hour, and the flow rate of the polyaluminium chloride aqueous solution medicament is set to be 2.2 liters/hour;

(2) introducing DN50 pipeline mixer for mixing reaction in the pipeline, wherein the mixing time in the pipeline is about 5-10 seconds;

(3) the water after reaction passes through a self-cleaning filter of 150 microns, and flocculated precipitates are intercepted;

(4) the water after passing through the self-cleaning filter enters an ultrafiltration membrane for filtering, the filtering aperture reaches 0.001 micron, meanwhile, the water has a certain effect of intercepting and removing residual aluminum in the traditional Chinese medicine in the water body, the water yield is 95 percent, and the treated water meets the requirements of the national sanitary Standard for Drinking Water;

Through the treatment, the fluorine content of the effluent is 0.6mg/L, the turbidity is less than 0.1NTU, the aluminum content is 0.103mg/L, and the requirements of corresponding indexes in the national sanitary Standard for Drinking Water are met.

Example 3, the fluorine content of the raw water is 4.0mg/L, and based on the drinking water fluorine removal treatment system provided by the invention, the following treatment steps are adopted:

(1) the flow rate of the inlet water is set to be 2 tons/hour, and the flow rate of the mixed liquid of the polyaluminium chloride and the aluminium sulfate is set to be 1.8 liters/hour;

(3) the water after reaction passes through a 100-micron self-cleaning filter to intercept coagulating sedimentation;

(4) the water after passing through the self-cleaning filter enters an ultrafiltration membrane for filtering, the filtering aperture reaches 0.03 micron, meanwhile, the water has a certain effect of intercepting and removing residual aluminum in the traditional Chinese medicine in the water body, the water yield is 95 percent, and the obtained treated water meets the requirements of the national sanitary Standard for Drinking Water;

Through the treatment, the fluorine content of the effluent is 0.9mg/L, the turbidity is less than 0.1NTU, the aluminum content is 0.089mg/L, and the requirements of corresponding indexes in the national sanitary Standard for Drinking Water are met.

Example 4, the fluorine content of the raw water is 3.0mg/L, and based on the drinking water fluorine removal treatment system provided by the present invention, the following treatment steps are adopted:

(1) the water inlet flow is set to be 4 tons/hour, and the polyaluminium chloride aqueous solution medicament flow is set to be 3.3 liters/hour;

(3) the water after reaction passes through a 100-200 micron self-cleaning filter to intercept coagulating sedimentation;

(4) the water after passing through the self-cleaning filter enters an ultrafiltration membrane for filtering, the filtering aperture reaches 0.001 micron, meanwhile, the water has a certain interception and removal effect on residual aluminum in the medicinal agent in the water body, the water yield is 95 percent, and the obtained treated water meets the requirements of the national sanitary Standard for Drinking Water;

Through the treatment, the fluorine content of the effluent is 0.8mg/L, the turbidity is less than 0.1NTU, the aluminum content is 0.133mg/L, and the requirement of corresponding indexes in the national sanitary Standard for Drinking Water is met.

The amount of the fluorine-removing agent added varies depending on the raw water, and therefore, the amount of the fluorine-removing agent added needs to be adjusted according to the actual fluorine content of the raw water to be treated.

The self-cleaning filter used in the above embodiments can be a full-automatic self-cleaning filter, and the function of the self-cleaning filter is to automatically realize the interception and pollution discharge process, and further realize the automation of the whole process, specifically: most of large-particle-size floccules are intercepted firstly, and then a small amount of small-particle-size floccules are reserved for the membrane filter to be intercepted, so that the intercepting workload of the membrane filter is relieved, the service life of the membrane filter is prolonged, the working time in the cycle is prolonged (because if the self-cleaning filter is not arranged, the membrane filter can cause membrane clogging due to more intercepted floccules), and the pollution degree of the membrane is reduced.

The applicant declares that the present invention is described by the above embodiments to the detailed system flow of the present invention, but the present invention is not limited to the above detailed system flow, that is, it does not mean that the present invention must rely on the above detailed system flow to be implemented. It will be understood by those skilled in the art that any simple modification, equivalent substitution of each raw material and addition of auxiliary components, selection of specific modes and the like, of the product of the present invention falls within the scope and disclosure of the present invention.

For simplicity of explanation, the method embodiments are described as a series of acts or combinations, but those skilled in the art will appreciate that the present invention is not limited by the order of acts, as some steps may occur in other orders or concurrently in accordance with the invention. Further, those skilled in the art will appreciate that the embodiments described in the specification are preferred embodiments and that the acts and elements referred to are not necessarily required to practice the invention.

The drinking water defluorination treatment system provided by the invention is described in detail, and the principle and the implementation mode of the invention are explained by applying specific examples, and the description of the examples is only used for helping to understand the method and the core idea of the invention; meanwhile, for a person skilled in the art, according to the idea of the present invention, there may be variations in the specific embodiments and the application scope, and in summary, the content of the present specification should not be construed as a limitation to the present invention.

Claims

1. A drinking water defluorination treatment system, said system comprising: a defluorination medicament adding device, a pipeline mixing device, a membrane filtering device and a central control device;

2. The system of claim 1, wherein the membrane filtration device comprises a self-cleaning filter having a filter mesh pore size of 100-200 microns, and a membrane filter having a filter membrane pore size of 0.001-0.1 microns;

3. The system of claim 2, wherein the self-cleaning filter is provided with a first drain port; and the first drain port is used for periodically draining the wastewater containing the filtered sediments and intercepted by the self-cleaning filter.

4. The system of claim 2, further comprising a backwash assembly; the flushing port of the backwashing device is arranged at the upper part of the water producing side of the filtering membrane;

5. The system of claim 4, wherein the backwash assembly comprises a backwash assembly;

6. The system of claim 2, further comprising an air purge device; and the air inlet of the air washing device is arranged at the lower part of the water inlet side of the filtering membrane.

7. The system according to claim 6, wherein the gas-washing device (7) comprises a gas-washing assembly;

the air washing component comprises a vortex air pump, wherein an air outlet of the vortex air pump is used as an air inlet and is arranged at the lower part of the water inlet side of the filtering membrane.

8. The system of claim 2, further comprising a drug washing device; the medicine inlet of the medicine washing device is arranged at the lower part of the water inlet side of the filtering membrane.

9. The system of claim 8, wherein the drug washing device comprises a drug washing assembly comprising: a medicament box, a medicament feeding pump and a medicament inlet pipe; the medicament feeding pump is arranged on the medicament inlet pipe in series; one end of the medicine inlet pipe is communicated with the chemical box, and the outlet of the other end of the medicine inlet pipe is used as the medicine washing inlet and is arranged at the lower part of the water inlet side of the filtering membrane.

10. The system of claim 6 or 8, wherein a second sewage draining outlet is arranged on the membrane filter; the second sewage draining outlet is arranged on the water producing side of the membrane filter, which is close to the filtering membrane, and is used for discharging the waste water which is intercepted by the filtering membrane and contains the filtering sediment and discharging the waste water which is subjected to gas washing and/or medicine washing.

11. The system of claim 4 or 5, wherein a third sewage draining outlet is arranged on the membrane filter; and the third sewage discharge port is arranged on the water inlet side of the filtering membrane in the membrane filter and is used for discharging backwashing wastewater.

12. The system of claim 1, wherein the fluorine removal agent dosing device comprises: a defluorination medicament box, a defluorination medicament adding pump and a defluorination medicament inlet pipe;

13. The system of claim 1, wherein the central control device comprises a defluorinating agent control module;

and the defluorination agent control module is used for controlling the defluorination agent adding device and monitoring the fluorine content of the produced water in the water producing side of the membrane filtering device and regulating and controlling the defluorination agent adding amount of the defluorination agent adding device according to the fluorine content.

14. The system of claim 4, 6 or 8, wherein the central control device further comprises a flush control module; the flushing control module is used for monitoring the water inlet and outlet pressure difference of the filtering membrane and controlling whether to start the backwashing device, the air washing device or the medicine washing device and/or start the backwashing device, the air washing device or the medicine washing device according to the water inlet and outlet pressure difference

15. The system according to any one of claims 1 to 14, wherein the central control device further comprises an electric control device, and the system integrally controls the opening or closing of all electric valves in the system through the electric control device.