Ozone synergistic pulse cleaning system and method for internal pressure type hollow fiber ultrafiltration membrane

Abstract

The application discloses a method for ozone synergistic pulse cleaning of a hollow fiber ultrafiltration membrane. The ozone mixed solution is used as a cleaning medium. The electromagnetic valve in a pulse water supply branch is opened and closed at a certain frequency. When the electromagnetic valve is opened, the cleaning medium flows into a cleaning main pipe through a pipeline where the electromagnetic valve is located, and the water pressure is high. When the electromagnetic valve is closed, the cleaning medium flows into the cleaning main pipe through an electromagnetic pressure reducing valve, and the water pressure is low. Water hammer is discharged by an electromagnetic overflow valve, so that pulse water supply is formed. The application realizes rapid switching in the cleaning process of the hollow fiber membrane, accurate control of the highest and lowest pressurizing values in each period, and avoidance of the negative influence of water hammer and air hammer on the membrane water production. The pulse type forward and reverse flushing is combined, and the membrane pollution removal is more thorough. The device also increases the pollution removal capacity through ozone micro-bubble explosion of the cleaning medium.

Description

Technical Field

[0001] This invention relates to the field of water treatment technology, and in particular to a cleaning device and method for water-contaminated filter membranes. Background Technology

[0002] Hollow fiber ultrafiltration membranes are made of asymmetric polymers and have a fibrous shape. The inner surface of the membrane is a very thin membrane with self-supporting properties, which allows the ultrafiltration membrane to be backwashed. At the same time, pollutants in the ultrafiltration process are not easily retained inside the membrane to form deep fouling, so it has stronger antifouling performance and easy cleaning recovery. In addition, the advantages of high flow channel density per unit packing, high membrane specific surface area, low operating pressure, low energy consumption, high flux and backwashing ability make it widely used in material separation and various water treatments.

[0003] In internal pressure hollow fiber ultrafiltration membranes, the feed solution enters through the inner pores of the membrane fibers. Driven by a relatively low pressure difference, it is separated and filtered according to the molecular weight of the solute, permeating radially from the inside out through the hollow fibers. Therefore, the permeate containing water, ions, and low molecular weight substances collects on the outer side of the membrane fibers, while high molecular weight organic matter, bacteria, suspended particles, pyrogens, and various colloids of silicon, iron, and aluminum, as well as bacteria, viruses, and protozoa, are retained within the membrane fibers. The vast majority of these pollutants are discharged as concentrate, with a small amount remaining and accumulating on the membrane surface. External pressure hollow fiber ultrafiltration membranes, on the other hand, filter the feed solution from the outside to the inside of the membrane, achieving the retention of pollutants.

[0004] After a period of operation, as pollutants are increasingly trapped and accumulated on the membrane surface, the membrane flux will decrease or the operating pressure will increase, requiring regular cleaning of the membrane.

[0005] In the selection of physical cleaning methods for hollow fiber ultrafiltration membranes, since hollow fiber ultrafiltration membranes are made of columnar, high-density membrane fibers per unit cross-section, ultrasonic cleaning cannot be implemented. Therefore, pulse cleaning is the most efficient physical cleaning method among existing physical cleaning methods for hollow fiber membranes. This method uses pulsed cleaning water to pass through the membrane surface where pollutants are trapped and accumulated, and the membrane surface is cleaned through the combined action of vibration and impact.

[0006] Among the pulse cleaning methods for ordinary filter membranes, gas-liquid pulse is the most common. This method involves introducing high-pressure gas through gaps in a uniformly flowing liquid cleaning medium to form a pulsed fluid, which impacts contaminants in the form of an air hammer to achieve the purpose of decontamination. However, for hollow fiber membranes, the impact of the air hammer can easily rupture the hollow fiber membrane, leading to damage such as broken fibers and leakage.

[0007] Intermittent flow is another form of pulse cleaning, which achieves intermittent pressure application and cessation of the cleaning medium. However, this method is prone to damage because the average pressure change during each pulse cycle exceeds the maximum pressure variation range that the hollow fiber membrane can withstand.

[0008] The high-low pressure differential continuous medium pulse cleaning method is currently the safest pulse cleaning method for hollow fiber membranes. In each pulse cycle, the highest and lowest pressure values ​​in each cycle are quickly switched and precisely controlled to ensure the feed water pressure for cleaning the hollow fiber membrane while avoiding pressure changes in the pulse cleaning medium that exceed the membrane's maximum pressure range, thus achieving efficient membrane cleaning.

[0009] At present, continuous medium pulse cleaning with high and low pressure difference cannot be achieved by adjusting the medium pressure with a variable frequency water pump. This is because the pressure adjustment time of the variable frequency water pump is relatively long, which cannot meet the requirements of short-cycle high and low pressure rapid switching of medium pulse cleaning.

[0010] The specification of invention patent "CN107073404A" discloses two pulse cleaning methods for membranes. One method involves using a solenoid valve in the pipeline at the front end of the cleaning medium booster pump for control. The intermittent flow pulse cleaning is achieved by rapidly switching the opening and closing of the solenoid valve. However, in addition to the intermittent flow being unsuitable for hollow fiber membranes, as mentioned above, the water hammer formed during the closing of the solenoid valve can also impact the pipeline, adversely affecting the water production of the booster pump. The other method involves introducing a bypass pipeline in the pipeline at the front end of the booster pump. This bypass pipeline extends to a water tank and is equipped with a solenoid pressure reducing valve. The opening and closing of the solenoid pressure reducing valve achieves the highest pressure when closed and the lowest pressure when open, thus achieving continuous medium pulse cleaning with high and low pressure differences. However, the biggest problem with this method is that water hammer also forms the moment the solenoid pressure reducing valve closes. This makes it impossible to meet the precise control of the high and low pressure switching of the medium, and it is very easy to exceed the high pressure tolerance range and the maximum pressure change tolerance range of the hollow fiber membrane, leading to membrane damage. Summary of the Invention

[0011] The purpose of this invention is to at least address the aforementioned technical deficiencies and achieve rapid switching and precise control of the highest and lowest pressure values ​​for pulse cleaning of hollow fiber ultrafiltration membranes.

[0012] Therefore, this invention proposes an ozone-coordinated pulse cleaning system for cross-flow filtration internal pressure hollow fiber ultrafiltration membranes, including a membrane treatment device, a finished product water tank, and a cleaning device;

[0013] The membrane treatment device includes an ultrafiltration membrane booster pump, two or more hollow fiber ultrafiltration membranes connected in parallel, two or more filter outlet pipes connected in parallel, two or more filter water branch pipes, a filter water main pipe, an intermediate water tank, and a sewage discharge main pipe.

[0014] The hollow fiber ultrafiltration membrane is a columnar, cross-flow filtration internal pressure hollow fiber membrane with high unit packing density.

[0015] The outlet pipe of the ultrafiltration membrane booster pump is equipped with a solenoid valve and a pressure sensor in sequence along the water flow direction;

[0016] The ultrafiltration membrane booster pump is connected in parallel to the lower end of two or more hollow fiber ultrafiltration membranes. The two filtered water outlets corresponding to one hollow fiber ultrafiltration membrane are connected to each other by pipes to form the parallel filtered water outlet pipe. The parallel filtered water outlet pipe is connected to the filtered water branch pipe. Two or more filtered water branch pipes are connected to the inlet end of the filtered water main pipe. The outlet end of the filtered water main pipe is connected to the intermediate water tank.

[0017] Two or more hollow fiber ultrafiltration membrane outlet water pipes are connected to the sewage main pipe;

[0018] The sewage trunk line can be connected to the municipal sewage pipeline for discharge, or it can be connected to a water storage tank for use as greywater.

[0019] The solenoid valve is installed on the filtered water branch pipe;

[0020] The filter water main pipe is sequentially equipped with the pressure sensor, the conductivity sensor, and the solenoid valve along the water flow direction;

[0021] The top of the finished water tank is equipped with a breather;

[0022] The cleaning device includes a concentrated water tank, a gas-liquid mixing branch, a bypass pipeline, a pulse water supply branch, a cleaning main pipe, a forward washing branch, a backwashing branch, and a downstream sewage branch.

[0023] The gas-liquid mixing branch is provided with, in sequence along the water flow direction, a gas-liquid mixing frequency booster pump, a pressure sensor, a solenoid valve, an ejector, a mixer, a flow meter, a check valve, and an electric valve.

[0024] The electric valve in the gas-liquid mixing branch is connected to the water inlet at the top of the finished water tank;

[0025] In the gas-liquid mixing branch, the bypass pipeline is connected in parallel between the water outlet pipe of the pressure sensor and the water outlet pipe of the check valve.

[0026] The solenoid valve is installed on the bypass pipeline;

[0027] The air inlet pipe of the jet injector is sequentially equipped with an ozone generator and a gas flow controller along the airflow direction;

[0028] The outlet of the finished water tank is connected to the inlet of the gas-liquid mixing variable frequency booster pump.

[0029] The pulse water supply branch includes an electromagnetic overflow valve, an electromagnetic pressure reducing valve, and the electromagnetic valve.

[0030] The electromagnetic overflow valve, the electromagnetic pressure reducing valve, and the inlet pipe of the electromagnetic valve in the pulse water supply branch are connected to the outlet pipe of the check valve.

[0031] The outlet pipe of the electromagnetic overflow valve is connected to the finished water tank;

[0032] The parallel water outlet pipes of the solenoid valve and the solenoid pressure reducing valve in the pulse water supply branch are connected to the cleaning main pipe.

[0033] Each hollow fiber ultrafiltration membrane corresponds to one forward washing branch and one backwashing branch. The outlet of the forward washing branch is connected to the lower end connection pipe of the hollow fiber ultrafiltration membrane, and the outlet of the backwashing branch is connected to the corresponding parallel filter outlet pipe.

[0034] The forward washing branch and the reverse washing branch are respectively equipped with the solenoid valve;

[0035] The check valve is installed at the connection between the outlet pipe of the ultrafiltration membrane booster pump and the outlet of the forward wash branch.

[0036] The lower sewage branch is equipped with the solenoid valve. The inlet of the lower sewage branch is connected to the lower pipe of the hollow fiber ultrafiltration membrane, and the outlet of the lower sewage branch is connected to the main sewage pipe.

[0037] The sewage main pipe is connected to the concentrate tank;

[0038] The respirator is located at the top of the concentrate tank.

[0039] For hollow fiber ultrafiltration membranes with strong antioxidant properties, this invention proposes a method for ozone-coordinated pulse cleaning of hollow fiber ultrafiltration membranes using an ozone-coordinated pulse cleaning system operating in a cross-flow filtration internal pressure type.

[0040] Relevant parameters:

[0041] The pressure value measured by the pressure sensor in the outlet pipe of the ultrafiltration membrane booster pump is P1;

[0042] The pressure value at the permeate outlet of the hollow fiber ultrafiltration membrane, measured by the pressure sensor in the filtered water main, is P2.

[0043] The conductivity value measured by the conductivity sensor in the filtered water main pipe is S;

[0044] The flow rate measured by the flow meter in the gas-liquid mixing branch is M1 per unit time;

[0045] The gas flow rate measured by the gas flow controller per unit time is M2;

[0046] The ozone generator produces ozone at a concentration of N;

[0047] The pressure value measured by the pressure sensor in the gas-liquid mixing branch is P3;

[0048] The hollow fiber ultrafiltration membrane is rinsed after a cumulative water production time of T1. In each rinsing, the duration of each pulse forward wash cycle is T2, and the duration of each pulse backwash cycle is T3.

[0049] The electromagnetic overflow valve is set to a pressure of P4, meaning that the pressure in the water inlet pipe of the electromagnetic overflow valve is not greater than P4.

[0050] The electromagnetic pressure reducing valve is set to pressure P5, meaning that the pressure in the outlet pipe after the liquid flows through the electromagnetic pressure reducing valve is no greater than P5.

[0051] The pulse water supply frequency in the pulse water supply branch is F;

[0052] The interval for disinfection of the filtered water stored in the finished water tank is T4, and the disinfection duration is T5.

[0053] Including the following steps:

[0054] 1) The water production steps of the hollow fiber ultrafiltration membrane:

[0055] The parameters of the inlet pressure during the water production process of the hollow fiber ultrafiltration membrane are set according to the quality of the filtered raw water and the design process of the hollow fiber ultrafiltration membrane.

[0056] Water production: The solenoid valves of the ultrafiltration membrane booster pump outlet pipe, the filter water branch pipe, and the filter water main pipe are opened, the ultrafiltration membrane booster pump is turned on and supplies water at constant pressure, that is, monitoring P1 equals the pressure parameter set at the inlet of the hollow fiber ultrafiltration membrane; in this step, the raw water flows through the ultrafiltration membrane booster pump, the lower end of the hollow fiber ultrafiltration membrane, and the parallel filter outlet pipe to complete filtration and form product water. Then the product water flows through the filter water branch pipe into the filter water main pipe and finally into the intermediate water tank. At the same time, the concentrated water flows through the upper end of the hollow fiber ultrafiltration membrane and the sewage discharge main pipe to the municipal sewage pipe or to the concentrated water tank.

[0057] Warning:

[0058] T1 is set according to the quality of the filtered raw water and the design process of the hollow fiber ultrafiltration membrane;

[0059] During the water production process of the hollow fiber ultrafiltration membrane, when the water production time = T1 or P1-P2 > the maximum permeate pressure difference (TMP) or S is greater than the set value, the device stops operating and issues an early warning to wait for cleaning.

[0060] 2) The pulse forward washing step of the hollow fiber ultrafiltration membrane:

[0061] Based on the quality of the filtered raw water and the design process of the hollow fiber ultrafiltration membrane, parameters such as T2, the high value of the pulse cleaning inlet water pressure at the bottom of the hollow fiber membrane during the forward washing process, and the concentration of ozone mixed solution are set respectively.

[0062] Water production device shutdown: The solenoid valves of the ultrafiltration membrane booster pump outlet pipe, the filter water branch pipe, and the filter water main pipe are closed, and the ultrafiltration membrane booster pump is shut down.

[0063] Constant pressure water supply at the front end of the cleaning device: In the cleaning device, the gas-liquid mixing variable frequency booster pump is turned on and performs constant pressure control, that is, monitoring the parameter P3 to be equal to the high value of the pulse cleaning inlet water pressure at the bottom of the hollow fiber membrane during the forward washing process, and then the gas-liquid mixing variable frequency booster pump outputs stable power; the solenoid valve in the gas-liquid mixing branch is turned on and the electric valve is turned off; the solenoid valve in the bypass pipeline is turned off; in this step, the filtered water in the finished water tank is supplied with constant pressure by the gas-liquid mixing variable frequency booster pump at the high value of the pulse inlet water pressure required for forward washing;

[0064] To achieve ozone mixing: the ozone generator and the gas flow controller are turned on, and the gas flow controller controls the ozone flow rate, so that ρ 臭氧 *N*M2 / M1 is equal to the set parameter for the ozone mixture concentration during the forward washing process; in this step, the filtered water forms an ozone mixture in the ejector;

[0065] Ozone-coordinated pulse water supply for the cleaning device: In the pulse water supply branch, the electromagnetic overflow valve is opened, and P4 is set to be equal to the high-value parameter of the pulse inlet water pressure at the lower end of the hollow fiber ultrafiltration membrane during the forward washing process; the electromagnetic pressure reducing valve is opened, and P5 is set such that (P4-P5)*F ≤ the maximum pressure change value per unit time that the hollow fiber ultrafiltration membrane can withstand; F is set to any value in the range of 0.2~5, and the electromagnetic valves in the pulse water supply branch open and close at a frequency of F; the electromagnetic valves in two or more forward washing branches are open, the electromagnetic valves in two or more backwashing branches are closed, and the electromagnetic valves in two or more lower sewage branches are closed; in this step, the ozone mixture is used as the cleaning medium, and the electromagnetic valves in the pulse water supply branch open and close at a frequency of F. During the opening and closing of the frequency, when the solenoid valve is open, the cleaning medium flows into the cleaning main pipe through the pipe where the solenoid valve is located. Therefore, the water pressure at this time is the forward wash setting P4 value. When the solenoid valve is closed, the cleaning medium flows into the cleaning main pipe through the solenoid pressure reducing valve at the forward wash setting P5 value. The water hammer formed during the closing of the solenoid valve will overflow through the solenoid overflow valve. This forms a pulse water supply to the cleaning main pipe with the forward wash setting P4 and P5 as the highest and lowest pressure values, respectively. Then, the cleaning medium flows sequentially through the forward wash branch to the lower port of the hollow fiber ultrafiltration membrane, the pollutant accumulation surface of the inner membrane fibers of the hollow fiber ultrafiltration membrane, the upper port of the hollow fiber ultrafiltration membrane, and the sewage discharge main pipe to the concentrate tank, thereby realizing the ozone-coordinated pulse forward wash of the hollow fiber ultrafiltration membrane.

[0066] 3) The pulse backwashing step of the hollow fiber ultrafiltration membrane:

[0067] Once the pulse forward wash T2 reaches the set duration, immediately switch to pulse backwash. Set the parameters for T3 and the high value of the pulse inlet pressure of the hollow fiber ultrafiltration membrane during the backwashing process according to the quality of the filtered raw water and the design process parameters of the hollow fiber ultrafiltration membrane.

[0068] The water purification device remains closed.

[0069] Constant pressure water supply at the front end of the cleaning device: In the cleaning device, the gas-liquid mixing variable frequency booster pump is turned on and performs constant pressure control, that is, monitoring the parameter P3, which is equal to the high value of the pulse inlet water pressure of the hollow fiber ultrafiltration membrane during the backwashing process; the solenoid valve in the bypass pipeline is turned on; the solenoid valve, the electric valve, the ozone generator, and the gas flow controller in the gas-liquid mixing branch are turned off; in this step, the filtered water in the finished water tank is used as the rinsing medium and is supplied with constant pressure through the bypass pipeline at the high value of the pulse inlet water pressure required for backwashing by the gas-liquid mixing variable frequency booster pump.

[0070] Pulse water supply for cleaning device: In the pulse water supply branch, the electromagnetic overflow valve is opened, and P4 is set to be equal to the high value parameter of the pulse inlet water pressure of the hollow fiber ultrafiltration membrane during the backwashing process; the electromagnetic pressure reducing valve is opened, and P5 is set such that (P4-P5)*F≤ the maximum pressure change value per unit time that the hollow fiber ultrafiltration membrane can withstand; F is set to any value in the range of 0.2~5, and the electromagnetic valves in the pulse water supply branch open and close at a frequency of F; the electromagnetic valves in two or more of the forward washing branches are closed, the electromagnetic valves in two or more of the backwashing branches are open, and the electromagnetic valves in two or more of the downstream sewage branches are open; in this step, during the opening and closing of the electromagnetic valves in the pulse water supply branch at a frequency of F, when the electromagnetic valves open and close, the cleaning medium... When the solenoid valve is open, the cleaning medium flows through the cleaning main pipe via the pipe where the solenoid valve is located. Therefore, the water pressure at this time is the backwash setting value P4. When the solenoid valve is closed, the cleaning medium is supplied to the cleaning main pipe via the solenoid pressure reducing valve at the backwash setting value P5. The water hammer formed during the closing of the solenoid valve will overflow through the solenoid overflow valve, thereby forming a pulse water supply to the cleaning main pipe with the backwash setting values ​​P4 and P5 as the highest and lowest pressure values. Then, the cleaning medium flows sequentially through the backwash branch and the parallel filter outlet pipe to backwash the membrane fibers of the hollow fiber ultrafiltration membrane. Wastewater is discharged from the upper and lower ports of the hollow fiber ultrafiltration membrane to the sewage discharge main pipe at the same time, and finally flows to the concentrate tank, thereby realizing the pulse backwashing of the membrane fibers in the hollow fiber ultrafiltration membrane.

[0071] Once T3 duration is reached, shut down the equipment that was turned on during the backwashing process;

[0072] 4) The step of storing filtered water in the finished water tank for ozone mixed liquid circulation disinfection:

[0073] The parameters of T4, T5, circulating disinfection water supply pressure and ozone mixed solution concentration are set according to the water quality requirements of the finished water in the finished water tank. When T4 reaches the set time and the forward and backwashing of the hollow fiber ultrafiltration membrane stops, the filtered water stored in the finished water tank is disinfected. The disinfection step is not affected by whether the hollow fiber ultrafiltration membrane is producing water.

[0074] Shut down some of the equipment in the cleaning device: only turn on the equipment in the gas-liquid mixing branch, and turn off all other equipment in the cleaning device;

[0075] Ozone-liquid mixture circulation disinfection: The gas-liquid mixing variable frequency booster pump is under constant pressure control, i.e., monitoring P3 to ensure it equals the set circulation disinfection water supply pressure; the ozone generator and the gas flow controller are activated, and the gas flow controller controls the ozone flow rate, ensuring that ρ... 臭氧*N*M2 / M1 is equal to the set parameter of ozone concentration in the ozone mixture circulation disinfection process; this process circulates ozone into the stored filtered water in the finished product water tank.

[0076] Once T4 duration is reached, shut down the equipment that was turned on during the ozone mixed liquid circulation disinfection process.

[0077] For hollow fiber ultrafiltration membranes with weaker antioxidant properties, this invention proposes a method for pulse cleaning of hollow fiber ultrafiltration membranes using an ozone-coordinated pulse cleaning system with cross-flow internal pressure type, comprising the following steps:

[0078] Except for adjusting the forward washing steps of the ozone-coordinated pulse cleaning method for hollow fiber ultrafiltration membranes, all other steps remain unchanged; the adjusted forward washing steps are as follows:

[0079] The parameters for the high pulse inlet pressure of the hollow fiber membrane are set according to the quality of the filtered raw water and the design process of the hollow fiber ultrafiltration membrane, including T1, T2 and the forward washing process.

[0080] The water purification system remains off;

[0081] Constant pressure water supply at the front end of the cleaning device: In the cleaning device, the gas-liquid mixing variable frequency booster pump is turned on and performs constant pressure control, that is, monitoring the parameter P3, which is equal to the high value of the pulse inlet water pressure at the lower end of the hollow fiber ultrafiltration membrane during the forward washing process; the solenoid valve and the electric valve in the gas-liquid mixing branch are closed; the solenoid valve in the bypass pipeline is open; the solenoid valves in two or more forward washing branches are open, the solenoid valves in two or more backwashing branches are closed, and the solenoid valve in the lower sewage branch is closed;

[0082] Pulse water supply for the cleaning device: In the pulse water supply branch, the electromagnetic overflow valve is opened, and P4 is set to be equal to the high value of the pulse inlet water pressure at the lower end of the hollow fiber ultrafiltration membrane during the forward washing process; the electromagnetic pressure reducing valve is opened, and P5 is set such that (P4-P5)*F≤ the maximum pressure change per unit time that the hollow fiber ultrafiltration membrane can withstand; F is set to any value in the range of 0.2~5, and the electromagnetic valve in the pulse water supply branch opens and closes at a frequency of F.

[0083] This process removes ozone through the ozone mixing process in the forward washing step of the method of ozone-coordinated pulse cleaning of hollow fiber ultrafiltration membrane, using the filtrate in the finished product water tank as the cleaning medium for forward washing, while other processes remain unchanged.

[0084] This invention also proposes a direct drinking water system comprising an ozone-assisted pulse cleaning system with a cross-flow filtration internal pressure hollow fiber ultrafiltration membrane, the structure of which is as follows:

[0085] The direct drinking water system also includes a pretreatment device, a water supply branch, and a water return branch;

[0086] The pretreatment device includes a municipal pipeline, a raw water tank, a raw water tank outlet booster pump, a quartz sand filter, an activated carbon filter, and a water supply precision filter connected in sequence along the water flow direction.

[0087] The electric valve is installed at the connection point between the municipal pipeline and the original water tank.

[0088] The membrane treatment device also includes a nanofiltration booster pump and a nanofiltration unit;

[0089] The intermediate water tank, the nanofiltration booster pump, and the nanofiltration unit are connected in sequence by pipelines;

[0090] The nanofiltration unit's outlet water pipe is connected to the finished water tank, and a solenoid valve is installed at the outlet water pipe;

[0091] The water supply branch includes a water supply variable frequency booster pump, a pressure sensor, and a water supply ultraviolet lamp;

[0092] The finished water tank, the water supply variable frequency booster pump, the pressure sensor, and the water supply ultraviolet lamp are connected in sequence by pipes;

[0093] The return water branch includes the electric valve, the return water ultraviolet lamp, and the return water precision filter;

[0094] The electric valve, the return water ultraviolet lamp, and the return water precision filter are connected in sequence by pipelines;

[0095] The outlet pipe of the return water precision filter is connected to the inlet of the finished water tank.

[0096] The advantages and positive effects of this invention are as follows: A continuous medium pulse cleaning device with high and low pressure differentials can quickly switch and precisely control the highest and lowest pressure values ​​in each cycle, while avoiding water hammer and air hammer that could adversely affect membrane water production; combining pulsed forward and reverse flushing results in more thorough removal of membrane contaminants; the device also enhances contaminant removal capacity through ozone microbubble aeration of the cleaning medium; furthermore, when the filtered water in the finished product tank is stored for a long time, the ozone aeration device can also be used to disinfect the filtered water, expanding the device's application range. Attached Figure Description

[0097] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0098] Figure 1 This is a schematic diagram of the ozone-coordinated pulse cleaning system for the cross-flow filtration internal pressure hollow fiber ultrafiltration membrane of the present invention.

[0099] Figure 2 for Figure 1 A partial enlarged view of the cleaning device.

[0100] In the diagram, the components are: electric valve-a, solenoid valve-b, pressure sensor-c, conductivity sensor-d, breather-e, check valve-f, pretreatment device-1, municipal pipeline-11, raw water tank-12, raw water tank outlet booster pump-13, quartz sand filter-14, activated carbon filter-15, water supply precision filter-16, membrane treatment device-2, ultrafiltration membrane booster pump-21, hollow fiber ultrafiltration membrane-22, parallel filter outlet pipe-23, filtered water branch pipe-24, filtered water main pipe-25, intermediate water tank-26, sewage main pipe-27, nanofiltration booster pump-28, nanofiltration unit-29, finished water tank-3, and cleaning. Device-4, Concentrate Tank-41, Gas-Liquid Mixing Branch-42, Ejector-421, Gas Flow Controller-4211, Ozone Generator-4212, Mixer-422, Flow Meter-423, Gas-Liquid Mixing Variable Frequency Booster Pump-424, Bypass Pipeline-43, Pulse Water Supply Branch-44, Electromagnetic Overflow Valve-441, Electromagnetic Pressure Reducing Valve-442, Cleaning Main Pipe-45, Forward Washing Branch-46, Backwashing Branch-47, Downstream Sewage Branch-48, Water Supply Branch-5, Water Supply Variable Frequency Booster Pump-51, Water Supply Ultraviolet Lamp-52, Return Water Branch-6, Return Water Ultraviolet Lamp-61, Return Water Precision Filter-62. Detailed Implementation

[0101] The present invention will now be described in more detail with reference to the accompanying drawings, which illustrate preferred embodiments of the invention. It should be understood that those skilled in the art can modify the invention described herein while still achieving its advantageous effects. Therefore, the following description should be understood as being of general knowledge to those skilled in the art and is not intended to limit the invention.

[0102] Example 1: As Figure 1 , 2 As shown, an ozone-coordinated pulse cleaning system for a cross-flow internal pressure hollow fiber ultrafiltration membrane includes a membrane treatment device 2, a finished water tank 3, and a cleaning device 4.

[0103] The membrane treatment device 2 includes an ultrafiltration membrane booster pump 21, two or more hollow fiber ultrafiltration membranes connected in parallel 22, two or more filter outlet pipes connected in parallel 23, two or more filter water branch pipes 24, filter water main pipe 25, intermediate water tank 26, and sewage discharge main pipe 27.

[0104] Hollow fiber ultrafiltration membrane 22 is a columnar, cross-flow filtration internal pressure hollow fiber membrane with high unit packing density;

[0105] The outlet pipe of the ultrafiltration membrane booster pump 21 is equipped with a solenoid valve b and a pressure sensor c in sequence along the water flow direction;

[0106] An ultrafiltration membrane booster pump 21 is connected to the lower end of two or more hollow fiber ultrafiltration membranes 22. The two filtered water outlets corresponding to one hollow fiber ultrafiltration membrane 22 are connected to each other by pipes to form a filtered water outlet pipe 23. The filtered water outlet pipe 23 is connected to a filtered water branch pipe 24. Two or more filtered water branch pipes 24 are connected to the inlet end of a filtered water main pipe 25. The outlet end of the filtered water main pipe 25 is connected to an intermediate water tank 26.

[0107] Two or more hollow fiber ultrafiltration membranes 22 have their outlet water pipes connected to the sewage main pipe 27;

[0108] A solenoid valve b is installed on the filter water branch pipe 24;

[0109] The filtered water main pipe 25 is equipped with a pressure sensor c, a conductivity sensor d, and a solenoid valve b in sequence along the water flow direction.

[0110] The top of the finished water tank 3 is equipped with a breather e;

[0111] The cleaning device 4 includes a concentrated water tank 41, a gas-liquid mixing branch 42, a bypass pipeline 43, a pulse water supply branch 44, a cleaning main pipeline 45, a forward washing branch 46, a backwashing branch 47, and a downstream sewage branch 48.

[0112] Along the water flow direction, the gas-liquid mixing branch 42 is equipped with a gas-liquid mixing frequency booster pump 424, a pressure sensor c, a solenoid valve b, an ejector 421, a water mixer 422, a flow meter 423, a check valve f, and an electric valve a.

[0113] The electric valve a in the gas-liquid mixing branch 42 is connected to the water inlet at the top of the finished water tank 3;

[0114] In the gas-liquid mixing branch 42, a bypass pipe 43 is connected between the water outlet pipe of pressure sensor c and the water outlet pipe of check valve f.

[0115] Solenoid valve b is installed on bypass pipe 43;

[0116] The air inlet pipe of the jet injector 421 is sequentially equipped with an ozone generator 4212 and a gas flow controller 4211 along the airflow direction;

[0117] The outlet of the finished water tank 3 is connected to the inlet of the gas-liquid mixing variable frequency booster pump 424;

[0118] The pulse water supply branch 44 includes an electromagnetic overflow valve 441, an electromagnetic pressure reducing valve 442, and an electromagnetic valve b.

[0119] The inlet pipes of the electromagnetic overflow valve 441, electromagnetic pressure reducing valve 442, and electromagnetic valve b in the pulse water supply branch 44 are connected to the outlet pipe of the check valve f.

[0120] The outlet pipe of the electromagnetic overflow valve 441 is connected to the finished water tank 3;

[0121] The solenoid valve b and the solenoid pressure reducing valve 442 in the pulse water supply branch 44 are connected to the water outlet pipe and the cleaning main pipe 45.

[0122] Each hollow fiber ultrafiltration membrane 22 corresponds to a forward washing branch 46 and a backwashing branch 47. The outlet of the forward washing branch 46 is connected to the lower end of the hollow fiber ultrafiltration membrane 22, and the outlet of the backwashing branch 47 is connected to the corresponding filter outlet pipe 23.

[0123] Solenoid valves b are respectively installed in forward washing branch 46 and reverse washing branch 47;

[0124] A check valve f is installed at the connection between the outlet pipe of the ultrafiltration membrane booster pump 21 and the outlet of the forward wash branch 46;

[0125] The lower sewage branch 48 is equipped with a solenoid valve b. The inlet of the lower sewage branch is connected to the lower pipe of the hollow fiber ultrafiltration membrane 22, and the outlet of the lower sewage branch is connected to the sewage main pipe 27.

[0126] The sewage main 27 connects to the concentrate tank 41;

[0127] A breather e is installed at the top of the concentrate tank 41.

[0128] A method for performing ozone-coordinated pulse cleaning of a hollow fiber ultrafiltration membrane using an ozone-coordinated pulse cleaning system operating in a cross-flow filtration internal pressure type includes the following steps:

[0129] Relevant parameters:

[0130] The pressure value measured by pressure sensor c in the outlet pipe of ultrafiltration membrane booster pump 21 is P1;

[0131] The pressure value at the product water outlet of the hollow fiber ultrafiltration membrane 22, measured by pressure sensor c in the filtered water main pipe 25, is P2.

[0132] The conductivity sensor (d) in the filtered water main pipe 25 measures the conductivity value as S;

[0133] The flow rate of liquid per unit time measured by the flow meter 423 in the gas-liquid mixing branch 42 is M1;

[0134] The gas flow rate measured by the gas flow controller 4211 per unit time is M2;

[0135] Ozone generator 4212 produces ozone with a concentration of N;

[0136] The pressure value measured by pressure sensor c in gas-liquid mixing branch 42 is P3;

[0137] After the hollow fiber ultrafiltration membrane 22 has accumulated a water production time of T1, it is flushed. In each flush, the duration of each pulse forward wash cycle is T2, and the duration of each pulse backwash cycle is T3.

[0138] The electromagnetic overflow valve 441 is set to a pressure of P4, meaning that the pressure in the water inlet pipe of the electromagnetic overflow valve is not greater than P4.

[0139] The electromagnetic pressure reducing valve 442 is set to pressure P5, meaning that the pressure in the outlet pipe after the liquid flows through the electromagnetic pressure reducing valve is not greater than P5.

[0140] The pulse water supply frequency in pulse water supply branch 44 is F;

[0141] The interval for disinfection of filtered water stored in finished water tank 3 is T4, and the disinfection duration is T5.

[0142] 1) Water purification steps of hollow fiber ultrafiltration membrane 22:

[0143] The parameters of the inlet pressure during the water production process of the hollow fiber ultrafiltration membrane are set according to the quality of the filtered raw water and the design process of the hollow fiber ultrafiltration membrane 22.

[0144] Water production: The solenoid valves b of the outlet pipe of the ultrafiltration membrane booster pump 21, the filter water branch pipe 24, and the filter water main pipe 25 are opened, the ultrafiltration membrane booster pump 21 is turned on and supplies water at constant pressure, that is, the monitoring P1 is equal to the pressure parameter set at the inlet of the hollow fiber ultrafiltration membrane; in this step, the raw water flows through the ultrafiltration membrane booster pump 21, the lower end of the hollow fiber ultrafiltration membrane 22, and the filter outlet pipe 23 to complete filtration and form product water. Then the product water flows through the filter water branch pipe 24 into the filter water main pipe 25 and finally into the intermediate water tank 26. At the same time, the concentrated water flows through the upper end of the hollow fiber ultrafiltration membrane 22 and the sewage discharge main pipe 27 to the municipal sewage pipe or to the concentrated water tank 41.

[0145] Warning:

[0146] T1 is set according to the quality of the raw water to be filtered and the design process of the hollow fiber ultrafiltration membrane 22;

[0147] During the water production process of the hollow fiber ultrafiltration membrane 22, when the water production time = T1 or P1-P2 > the maximum permeate pressure difference TMP or S is greater than the set value, the device stops operating and issues an early warning to wait for cleaning.

[0148] 2) Pulse forward washing step of hollow fiber ultrafiltration membrane 22:

[0149] Based on the quality of the filtered raw water and the design process of the hollow fiber ultrafiltration membrane 22, the parameters of T2, the high value of the pulse cleaning inlet water pressure at the bottom of the hollow fiber membrane during the forward washing process, and the concentration of ozone mixed solution are set respectively.

[0150] Water purification device shutdown: Solenoid valve b of the outlet pipe of ultrafiltration membrane booster pump 21, solenoid valve b of filtered water branch pipe 24, and solenoid valve b of filtered water main pipe 25 are closed, and ultrafiltration membrane booster pump 21 is shut down.

[0151] Constant pressure water supply at the front end of the cleaning device: In the cleaning device 4, the gas-liquid mixing variable frequency booster pump 424 is turned on and performs constant pressure control, that is, it monitors the parameter P3, which is equal to the high value of the pulse cleaning inlet water pressure at the bottom of the hollow fiber membrane during the forward washing process, and then the gas-liquid mixing variable frequency booster pump outputs stable power; the solenoid valve b in the gas-liquid mixing branch 42 is opened and the electric valve a is closed; the solenoid valve b in the bypass pipeline 43 is closed; in this step, the filtered water in the finished water tank 3 is supplied with constant pressure by the gas-liquid mixing variable frequency booster pump 424 at the high value of the pulse inlet water pressure required for forward washing;

[0152] To achieve ozone mixing: the ozone generator 4212 and the gas flow controller 4211 are turned on. The gas flow controller controls the ozone flow rate, making ρ... 臭氧 *N*M2 / M1 is equal to the set parameter for the concentration of ozone mixture during the forward washing process; in this step, the filtered water forms an ozone mixture in the ejector 421;

[0153] Ozone-assisted pulse water supply for cleaning device: In pulse water supply branch 44, electromagnetic overflow valve 441 is opened, and P4 is set to be equal to the high value parameter of pulse water pressure at the lower end of hollow fiber ultrafiltration membrane 22 during the forward washing process; electromagnetic pressure reducing valve (442) is opened, and P5 is set so that P4-P5*F≤ the maximum pressure change value per unit time that the hollow fiber ultrafiltration membrane can withstand; F is set to any value in the range of 0.2~5, and electromagnetic valve b in pulse water supply branch 44 is opened and closed at a frequency of F; electromagnetic valve b in two or more forward washing branches 46 is opened, electromagnetic valve b in two or more backwash branches 47 is closed, and electromagnetic valve b in two or more lower sewage branches 48 is closed; in this step, ozone mixture is used as cleaning medium in pulse water supply branch 44, and electromagnetic valve b in pulse water supply branch 44 is opened at a frequency of F. During the opening and closing process, when the solenoid valve is open, the cleaning medium flows into the cleaning main pipe 45 through the pipe where the solenoid valve is located. Therefore, the water pressure at this time is the forward wash setting P4 value. When the solenoid valve is closed, the cleaning medium flows into the cleaning main pipe 45 through the solenoid pressure reducing valve 442 at the forward wash setting P5 value. The water hammer formed during the closing of the solenoid valve will overflow through the solenoid overflow valve 441, thereby forming a pulse water supply to the cleaning main pipe 45 with the forward wash setting P4 and P5 as the highest and lowest pressure values. Then the cleaning medium flows sequentially through the forward wash branch 46 to the lower end of the hollow fiber ultrafiltration membrane 22, the pollutant accumulation surface of the inner membrane fibers of the hollow fiber ultrafiltration membrane, the upper end of the hollow fiber ultrafiltration membrane, and the sewage discharge main pipe 27 to the concentrate tank 41, thereby realizing the ozone-coordinated pulse forward wash of the hollow fiber ultrafiltration membrane.

[0154] 3) Pulse backwashing step of hollow fiber ultrafiltration membrane 22:

[0155] Once the pulse forward wash T2 reaches the set duration, immediately switch to pulse backwash. Set the parameters for T3 and the high value of the pulse inlet pressure of the hollow fiber ultrafiltration membrane during the backwashing process according to the raw water quality being filtered and the design process parameters of the hollow fiber ultrafiltration membrane 22.

[0156] The water purification device remains closed.

[0157] Constant pressure water supply at the front end of the cleaning device: In the cleaning device 4, the gas-liquid mixing variable frequency booster pump 424 is turned on and constant pressure control is performed, that is, the parameter P3 is equal to the high value of the pulse water pressure of the hollow fiber ultrafiltration membrane 22 during backwashing, and then the gas-liquid mixing variable frequency booster pump outputs stable power; the solenoid valve b in the bypass pipeline 43 is turned on; the solenoid valve b, electric valve a, ozone generator 4212, and gas flow controller 4211 in the gas-liquid mixing branch 42 are turned off; in this step, the filtered water in the finished water tank 3 is used as the rinsing medium and is supplied with constant pressure through the bypass pipeline 43 by the gas-liquid mixing variable frequency booster pump 424 at the high value of the pulse water pressure required for backwashing.

[0158] Pulse water supply for cleaning device: In pulse water supply branch 44, electromagnetic overflow valve 441 is opened, and P4 is set to be equal to the high value parameter of pulse water pressure of hollow fiber ultrafiltration membrane 22 during backwashing; electromagnetic pressure reducing valve (442) is opened, and P5 is set so that P4-P5*F≤ the maximum pressure change value per unit time that the hollow fiber ultrafiltration membrane can withstand; F is set to any value in the range of 0.2~5, and electromagnetic valve b in pulse water supply branch 44 opens and closes at a frequency of F; electromagnetic valve b in two or more forward wash branches 46 is closed, electromagnetic valve b in two or more backwash branches 47 is open, and electromagnetic valve b in two or more downstream sewage branches 48 is open; in this step, during the opening and closing of electromagnetic valve b in pulse water supply branch 44 at a frequency of F, when the electromagnetic valve When the solenoid valve is turned on, the cleaning medium flows through the cleaning main pipe 45 via the pipe where the solenoid valve is located. Therefore, the water pressure at this time is the backwash setting P4 value. When the solenoid valve is turned off, the cleaning medium is supplied to the cleaning main pipe 45 via the solenoid pressure reducing valve 442 at the backwash setting P5 value. The water hammer formed during the process of closing the solenoid valve will overflow through the solenoid overflow valve 441, thereby forming a pulse water supply to the cleaning main pipe 45 with the backwash setting P4 and P5 as the highest and lowest pressure values. Then the cleaning medium flows through the backwash branch 47 and is connected to the filter outlet pipe 23 to backwash the membrane fibers of the hollow fiber ultrafiltration membrane 22. The sewage is discharged from the upper and lower ports of the hollow fiber ultrafiltration membrane to the sewage discharge main pipe 27 at the same time, and finally flows to the concentrate tank 41, thereby realizing the pulse backwashing of the membrane fibers in the hollow fiber ultrafiltration membrane.

[0159] Once T3 duration is reached, shut down the equipment that was turned on during the backwashing process;

[0160] 4) The process of storing filtered water in the finished water tank 3 for ozone mixed liquid circulation disinfection:

[0161] The parameters of T4, T5, circulating disinfection water supply pressure and ozone mixed solution concentration are set according to the water quality requirements of the finished water in the finished water tank. When T4 reaches the set time and the hollow fiber ultrafiltration membrane 22 stops running for forward and backwashing, the filtered water stored in the finished water tank 3 is disinfected. The disinfection step is not affected by whether the hollow fiber ultrafiltration membrane 22 is producing water.

[0162] Shut down some equipment in cleaning device 4: only turn on the equipment in gas-liquid mixing branch 42, and turn off all other equipment in cleaning device 4;

[0163] Ozone-liquid mixed circulation disinfection: The gas-liquid mixing variable frequency booster pump 424 performs constant pressure control, that is, it monitors P3 to be equal to the set circulating disinfection water supply pressure parameter; the ozone generator 4212 and the gas flow controller 4211 are turned on, and the gas flow controller 4211 controls the ozone flow rate, so that ρ 臭氧*N*M2 / M1 equals the set parameter for the ozone mixture concentration during the ozone mixture circulation disinfection process; this process circulates ozone into the stored filtered water in the finished water tank 3.

[0164] Once T4 duration is reached, shut down the equipment that was turned on during the ozone mixed liquid circulation disinfection process.

[0165] A direct drinking water system including an ozone-assisted pulse cleaning system with a cross-flow filtration internal pressure hollow fiber ultrafiltration membrane, the direct drinking water system also includes a pretreatment device 1, a water supply branch 5, and a water return branch 6.

[0166] The pretreatment device 1 includes a municipal pipeline 11, a raw water tank 12, a raw water tank outlet booster pump 13, a quartz sand filter 14, an activated carbon filter 15, and a water supply precision filter 16 connected sequentially along the water flow direction.

[0167] An electric valve a is installed at the connection point between the municipal pipeline 11 and the original water tank 12;

[0168] Membrane treatment device 2 also includes nanofiltration booster pump 28 and nanofiltration unit 29;

[0169] The intermediate water tank 26, the nanofiltration booster pump 28, and the nanofiltration unit 29 are connected in sequence by pipelines;

[0170] The nanofiltration unit 29 has an outlet water pipe connected to the finished water tank 3, and a solenoid valve b is installed at the outlet water pipe.

[0171] Water supply branch 5 includes a water supply variable frequency booster pump 51, a pressure sensor c, and a water supply ultraviolet lamp 52;

[0172] The finished water tank 3, the water supply frequency booster pump 51, the pressure sensor c, and the water supply ultraviolet lamp 52 are connected in sequence by pipes.

[0173] The return water branch 6 includes an electric valve a, a return water ultraviolet lamp 61, and a return water precision filter 62;

[0174] Electric valve a, return water ultraviolet lamp 61, and return water precision filter 62 are connected in sequence by pipes;

[0175] The outlet pipe of the return water precision filter 62 is connected to the inlet of the finished water tank 3.

[0176] Example 2: A method for pulse cleaning of a hollow fiber ultrafiltration membrane using an ozone-coordinated pulse cleaning system operating a cross-flow filtration internal pressure type hollow fiber ultrafiltration membrane, comprising the following steps:

[0177] Except for adjusting the forward washing step of the ozone-assisted pulse cleaning method for the hollow fiber ultrafiltration membrane in Example 1, all other steps remain unchanged; the adjusted forward washing step is as follows:

[0178] Based on the quality of the filtered raw water and the design process of the hollow fiber ultrafiltration membrane 22, the parameters of the high pulse inlet pressure of the hollow fiber membrane at the bottom are set for T1, T2 and the forward washing process.

[0179] The water purification system remains off;

[0180] Constant pressure water supply at the front end of the cleaning device: In the cleaning device 4, the gas-liquid mixing variable frequency booster pump 424 is turned on and performs constant pressure control, that is, it monitors the parameter P3, which is equal to the high value of the pulse water pressure at the lower end of the hollow fiber ultrafiltration membrane 22 during the forward washing process, and then the gas-liquid mixing variable frequency booster pump outputs stable power; the solenoid valve b and electric valve a in the gas-liquid mixing branch 42 are closed; the solenoid valve b in the bypass pipeline 43 is opened; the solenoid valve b in two or more forward washing branches 46 is opened; the solenoid valve b in two or more backwash branches 47 is closed; and the solenoid valve b in the lower sewage branch 48 is closed.

[0181] Pulse water supply for cleaning device: In pulse water supply branch 44, electromagnetic overflow valve 441 is opened, and P4 is set to be equal to the high value of the pulse water pressure at the lower end of hollow fiber ultrafiltration membrane 22 during the forward washing process; electromagnetic pressure reducing valve (442) is opened, and P5 is set so that P4-P5*F≤ the maximum pressure change value per unit time that the hollow fiber ultrafiltration membrane can withstand; F is set to any value in the range of 0.2~5, and electromagnetic valve b in pulse water supply branch 44 opens and closes at a frequency of F;

[0182] This process removes the ozone mixing process in the forward washing step of the ozone synergistic pulse cleaning method in Example 1, and uses the filtrate in the finished product water tank 3 as the cleaning medium for forward washing, while other processes remain unchanged.

[0183] Example 3: As Figure 1 As shown, a direct drinking water system includes an ozone-assisted pulse cleaning system with a cross-flow filtration internal pressure hollow fiber ultrafiltration membrane.

[0184] The direct drinking water system also includes a pretreatment device 1, a water supply branch line 5, and a return water branch line 6;

[0185] The pretreatment device 1 includes a municipal pipeline 11, a raw water tank 12, a raw water tank outlet booster pump 13, a quartz sand filter 14, an activated carbon filter 15, and a water supply precision filter 16 connected sequentially along the water flow direction.

[0186] An electric valve a is installed at the connection point between the municipal pipeline 11 and the original water tank 12;

[0187] Membrane treatment device 2 also includes nanofiltration booster pump 28 and nanofiltration unit 29;

[0188] The intermediate water tank 26, the nanofiltration booster pump 28, and the nanofiltration unit 29 are connected in sequence by pipelines;

[0189] The nanofiltration unit 29 has an outlet water pipe connected to the finished water tank 3, and a solenoid valve b is installed at the outlet water pipe.

[0190] Water supply branch 5 includes a water supply variable frequency booster pump 51, a pressure sensor c, and a water supply ultraviolet lamp 52;

[0191] The finished water tank 3, the water supply frequency booster pump 51, the pressure sensor c, and the water supply ultraviolet lamp 52 are connected in sequence by pipes.

[0192] The return water branch 6 includes an electric valve a, a return water ultraviolet lamp 61, and a return water precision filter 62;

[0193] Electric valve a, return water ultraviolet lamp 61, and return water precision filter 62 are connected in sequence by pipes;

[0194] The outlet pipe of the return water precision filter 62 is connected to the inlet of the finished water tank 3.

[0195] The present invention has been described in detail above through embodiments, but the content is only a preferred embodiment of the present invention and should not be considered as limiting the scope of the present invention. All equivalent changes and improvements made within the scope of the present invention should still fall within the patent coverage of the present invention.

Claims

1. An ozone-assisted pulse cleaning system for a cross-flow internal pressure hollow fiber ultrafiltration membrane, comprising a membrane treatment device (2), a finished water tank (3), and a cleaning device (4). The membrane treatment device (2) includes an ultrafiltration membrane booster pump (21), two or more hollow fiber ultrafiltration membranes connected in parallel (22), two or more filter outlet pipes connected in parallel (23), two or more filter water branch pipes (24), filter water main pipe (25), intermediate water tank (26), and sewage discharge main pipe (27). The hollow fiber ultrafiltration membrane (22) is a columnar, cross-flow filtration internal pressure hollow fiber membrane with high unit packing density; The outlet pipe of the ultrafiltration membrane booster pump (21) is equipped with a solenoid valve (b) and a pressure sensor (c) in sequence along the water flow direction. The ultrafiltration membrane booster pump (21) is connected in parallel to the lower end of two or more hollow fiber ultrafiltration membranes (22). The two filtered water outlets corresponding to one hollow fiber ultrafiltration membrane (22) are connected to each other to form the parallel filtered water outlet pipe (23). The parallel filtered water outlet pipe (23) is connected to the filtered water branch pipe (24). Two or more filtered water branch pipes (24) are connected to the inlet end of the filtered water main pipe (25). The outlet end of the filtered water main pipe (25) is connected to the intermediate water tank (26). Two or more hollow fiber ultrafiltration membranes (22) have their upper outlet water pipes connected to the sewage main pipe (27). The solenoid valve (b) is installed on the filter water branch pipe (24); The filtered water main pipe (25) is sequentially equipped with the pressure sensor (c), the conductivity sensor (d), and the solenoid valve (b) along the water flow direction. Its features are, The finished water tank (3) is equipped with a breather (e) on top; The cleaning device (4) includes a concentrated water tank (41), a gas-liquid mixing branch (42), a bypass pipeline (43), a pulse water supply branch (44), a cleaning main pipe (45), a forward washing branch (46), a backwash branch (47), and a downstream sewage branch (48). The gas-liquid mixing branch (42) is provided with the following components in sequence along the water flow direction: gas-liquid mixing frequency booster pump (424), pressure sensor (c), solenoid valve (b), jet ejector (421), water mixer (422), flow meter (423), check valve (f), and electric valve (a). The electric valve (a) in the gas-liquid mixing branch (42) is connected to the water inlet at the top of the finished water tank (3); In the gas-liquid mixing branch (42), the bypass pipeline (43) is connected in parallel between the outlet pipe of the pressure sensor (c) and the outlet pipe of the check valve (f). The solenoid valve (b) is installed on the bypass pipeline (43); The air inlet pipe of the jet injector (421) is sequentially equipped with an ozone generator (4212) and a gas flow controller (4211) along the airflow direction. The outlet of the finished water tank (3) is connected to the inlet of the gas-liquid mixing variable frequency booster pump (424); The pulse water supply branch (44) includes an electromagnetic overflow valve (441), an electromagnetic pressure reducing valve (442), and the electromagnetic valve (b). The electromagnetic overflow valve (441), the electromagnetic pressure reducing valve (442), and the electromagnetic valve (b) in the pulse water supply branch (44) are connected to the water inlet pipe of the check valve (f). The outlet pipe of the electromagnetic overflow valve (441) is connected to the finished water tank (3). The solenoid valve (b) and the solenoid pressure reducing valve (442) in the pulse water supply branch (44) are connected to the cleaning main pipe (45). Each hollow fiber ultrafiltration membrane (22) corresponds to a forward washing branch (46) and a backwashing branch (47). The outlet of the forward washing branch (46) is connected to the lower end of the hollow fiber ultrafiltration membrane (22), and the outlet of the backwashing branch (47) is connected to the corresponding parallel filter outlet pipe (23). The forward washing branch (46) and the reverse washing branch (47) are respectively equipped with the solenoid valve (b); The check valve (f) is provided at the connection between the outlet pipe of the ultrafiltration membrane booster pump (21) and the outlet of the forward washing branch (46). The lower sewage branch (48) is equipped with the solenoid valve (b), the inlet of the lower sewage branch is connected to the lower pipe of the hollow fiber ultrafiltration membrane (22), and the outlet of the lower sewage branch is connected to the sewage main pipe (27). The sewage main (27) is connected to the concentrate tank (41); The respirator (e) is located at the top of the concentrate tank (41).

2. A method for performing ozone-assisted pulse cleaning of a hollow fiber ultrafiltration membrane using an ozone-assisted pulse cleaning system operating according to claim 1, comprising the steps of: Relevant parameters: The pressure value measured by the pressure sensor (c) in the outlet pipe of the ultrafiltration membrane booster pump (21) is P1; 1) Water production steps of the hollow fiber ultrafiltration membrane (22): The parameters of the inlet pressure during the water production process of the hollow fiber ultrafiltration membrane are set according to the quality of the filtered raw water and the design process of the hollow fiber ultrafiltration membrane (22); Water production: When the solenoid valve (b) of the outlet pipe of the ultrafiltration membrane booster pump (21), the solenoid valve (b) of the filter water branch pipe (24), and the solenoid valve (b) of the filter water main pipe (25) are opened, the ultrafiltration membrane booster pump (21) is turned on and supplies water at constant pressure, that is, monitoring P1 is equal to the pressure parameter set at the inlet of the hollow fiber ultrafiltration membrane; in this step, the raw water flows through the ultrafiltration membrane booster pump (21), the lower end of the hollow fiber ultrafiltration membrane (22), and the parallel filter outlet pipe (23) to complete filtration and form product water. Then the product water flows through the filter water branch pipe (24) into the filter water main pipe (25) and finally into the intermediate water tank (26). At the same time, the concentrated water flows through the upper end of the hollow fiber ultrafiltration membrane (22) and the sewage main pipe (27) to the municipal sewage pipe or to the concentrated water tank (41) set up. Its features are: Other relevant parameters: The pressure value of the hollow fiber ultrafiltration membrane (22) outlet measured by the pressure sensor (c) in the filtered water main (25) is P2; The conductivity value measured by the conductivity sensor (d) in the filtered water main (25) is S; The flow rate measured by the flow meter (423) in the gas-liquid mixing branch (42) is M1 per unit time; The gas flow rate measured by the gas flow controller (4211) per unit time is M2; The ozone generator (4212) produces ozone with a concentration of N; The pressure value measured by the pressure sensor (c) in the gas-liquid mixing branch (42) is P3; The hollow fiber ultrafiltration membrane (22) is rinsed after a cumulative water production time of T1. In each rinse, the duration of each pulse forward wash cycle is T2, and the duration of each pulse backwash cycle is T3. The electromagnetic overflow valve (441) is set to a pressure of P4, meaning that the pressure in the water inlet pipe of the electromagnetic overflow valve is not greater than P4. The electromagnetic pressure reducing valve (442) is set to pressure P5, meaning that the pressure in the outlet pipe after the liquid flows through the electromagnetic pressure reducing valve is not greater than P5. The pulse water supply frequency in the pulse water supply branch (44) is F; The interval for disinfection of the filtered water stored in the finished water tank (3) is T4, and the disinfection time is T5. Warning: T1 is set according to the quality of the filtered raw water and the design process of the hollow fiber ultrafiltration membrane (22); During the water production process of the hollow fiber ultrafiltration membrane (22), when the water production time = T1 or P1-P2 > the maximum permeate pressure difference (TMP) or S is greater than the set value, the device stops operating and issues an early warning to wait for cleaning. 2) The pulse forward washing step of the hollow fiber ultrafiltration membrane (22): According to the quality of the filtered raw water and the design process of the hollow fiber ultrafiltration membrane (22), the parameters of T2, the pulse cleaning inlet pressure of the hollow fiber membrane during the forward washing process and the concentration of ozone mixture are set respectively. Water production device shutdown: The solenoid valve (b) of the outlet pipe of the ultrafiltration membrane booster pump (21), the solenoid valve (b) of the filter water branch pipe (24), and the solenoid valve (b) of the filter water main pipe (25) are closed, and the ultrafiltration membrane booster pump (21) is shut down. Constant pressure water supply at the front end of the cleaning device: In the cleaning device (4), the gas-liquid mixing variable frequency booster pump (424) is turned on and constant pressure control is performed, that is, monitoring P3 is equal to the parameter of the pulse cleaning inlet water pressure at the bottom of the hollow fiber membrane during the forward washing process, and then the gas-liquid mixing variable frequency booster pump outputs stable power; the solenoid valve (b) in the gas-liquid mixing branch (42) is turned on and the electric valve (a) is turned off; the solenoid valve (b) in the bypass pipeline (43) is turned off; in this step, the filtered water in the finished product water tank (3) is supplied with constant pressure by the gas-liquid mixing variable frequency booster pump (424) at the pulse inlet water pressure required for forward washing; To achieve ozone mixing: the ozone generator (4212) and the gas flow controller (4211) are turned on. The gas flow controller controls the ozone flow rate, making ρ... 臭氧 *N*M2 / M1 is equal to the set parameter of ozone mixture concentration during the forward washing process; in this step, filtered water forms an ozone mixture in the jet injector (421); Ozone-assisted pulse water supply for cleaning device: In the pulse water supply branch (44), the electromagnetic overflow valve (441) is opened, and P4 is set to be equal to the high value parameter of the pulse water pressure at the bottom of the hollow fiber ultrafiltration membrane (22) during the forward washing process; the electromagnetic pressure reducing valve (442) is opened, and P5 is set so that (P4-P5)*F≤ the maximum pressure change value per unit time that the hollow fiber ultrafiltration membrane can withstand; F is set to any value in the range of 0.2~5, and the electromagnetic valve (b) in the pulse water supply branch (44) is opened and closed at a frequency of F; the electromagnetic valve (b) in two or more forward washing branches (46) is opened, the electromagnetic valve (b) in two or more backwash branches (47) is closed, and the electromagnetic valve (b) in two or more bottom sewage branches (48) is closed; in this step, the ozone mixture is used as the cleaning medium in the electromagnetic valve of the pulse water supply branch (44). During the opening and closing of valve (b) at frequency F, when the solenoid valve is open, the cleaning medium flows into the cleaning main pipe (45) through the pipe where the solenoid valve is located. Therefore, the water pressure at this time is the forward wash setting P4 value. When the solenoid valve is closed, the cleaning medium flows into the cleaning main pipe (45) through the solenoid pressure reducing valve (442) at the forward wash setting P5 value. The water hammer formed during the closing of the solenoid valve will overflow through the solenoid overflow valve (441), thereby forming a pulse water supply to the cleaning main pipe (45) with the forward wash setting P4 and P5 as the highest and lowest pressure values. Then the cleaning medium flows through the forward wash branch (46) to the lower end of the hollow fiber ultrafiltration membrane (22), the pollutant accumulation surface of the inner membrane fiber of the hollow fiber ultrafiltration membrane, the upper end of the hollow fiber ultrafiltration membrane, the sewage discharge main pipe (27) to the concentrate tank (41), thereby realizing the ozone-coordinated pulse forward wash of the hollow fiber ultrafiltration membrane. 3) The pulse backwashing step of the hollow fiber ultrafiltration membrane (22): When the pulse forward wash T2 reaches the set duration, immediately switch to pulse backwash. Set the parameters of T3 and the high value of the pulse inlet water pressure of the hollow fiber ultrafiltration membrane during the backwashing process according to the water quality of the filtered raw water and the design process parameters of the hollow fiber ultrafiltration membrane (22). The water purification device remains closed. Constant pressure water supply at the front end of the cleaning device: In the cleaning device (4), the gas-liquid mixing variable frequency booster pump (424) is turned on and constant pressure control is performed, that is, the parameter P3 is equal to the high value of the pulse water inlet pressure of the hollow fiber ultrafiltration membrane (22) during the backwashing process, and then the gas-liquid mixing variable frequency booster pump outputs stable power; the solenoid valve (b) in the bypass pipeline (43) is turned on; the solenoid valve (b), the electric valve (a), the ozone generator (4212), and the gas flow controller (4211) in the gas-liquid mixing branch (42) are turned off; in this step, the filtered water in the finished product water tank (3) is used as the rinsing medium and is supplied with constant pressure through the bypass pipeline (43) by the gas-liquid mixing variable frequency booster pump (424) at the high value of the pulse water inlet pressure required for backwashing; Pulse water supply for cleaning device: In the pulse water supply branch (44), the electromagnetic overflow valve (441) is opened, and P4 is set to be equal to the high value parameter of the pulse water inlet pressure of the hollow fiber ultrafiltration membrane (22) during the backwashing process; the electromagnetic pressure reducing valve (442) is opened, and P5 is set so that (P4-P5)*F≤ the maximum pressure change value per unit time that the hollow fiber ultrafiltration membrane can withstand; F is set to any value in the range of 0.2~5, and the electromagnetic valve (b) in the pulse water supply branch (44) is opened and closed at a frequency of F; the electromagnetic valve (b) in two or more forward washing branches (46) is closed, the electromagnetic valve (b) in two or more backwashing branches (47) is opened, and the electromagnetic valve (b) in two or more downstream sewage branches (48) is opened; in this step, the cleaning medium is used to open and close the electromagnetic valve (b) in the pulse water supply branch (44) at a frequency of F. When the solenoid valve is opened, the cleaning medium flows through the cleaning main pipe (45) through the pipe where the solenoid valve is located. Therefore, the water pressure at this time is the P4 value set for backwashing. When the solenoid valve is closed, the cleaning medium is supplied to the cleaning main pipe (45) through the solenoid pressure reducing valve (442) with the backwash set P5 value. The water hammer formed during the process of closing the solenoid valve will overflow through the solenoid overflow valve (441), thereby forming a pulse water supply to the cleaning main pipe (45) with the backwash set P4 and P5 as the highest and lowest pressure values. Then the cleaning medium flows through the backwash branch (47) and the parallel filter outlet pipe (23) to backwash the membrane fibers of the hollow fiber ultrafiltration membrane (22). The sewage is discharged from the upper and lower ports of the hollow fiber ultrafiltration membrane to the sewage discharge main pipe (27) at the same time, and finally flows to the concentrate tank (41), thereby realizing the pulse backwashing of the membrane fibers in the hollow fiber ultrafiltration membrane. Once T3 duration is reached, shut down the equipment that was turned on during the backwashing process; 4) The step of storing filtered water in the finished water tank (3) for ozone mixed liquid circulation disinfection: The parameters of T4, T5, circulating disinfection water supply pressure and ozone mixed concentration are set according to the water quality requirements of the finished water in the finished water tank. When T4 reaches the set time and the hollow fiber ultrafiltration membrane (22) stops running for forward washing and back washing, the filtered water stored in the finished water tank (3) is disinfected. The disinfection step is not affected by whether the hollow fiber ultrafiltration membrane (22) is producing water. Shut down some of the equipment in the cleaning device (4): only turn on the equipment in the gas-liquid mixing branch (42), and turn off all the other equipment in the cleaning device (4); Ozone-liquid mixture circulation disinfection: The gas-liquid mixing variable frequency booster pump (424) is under constant pressure control, that is, monitoring that P3 equals the set circulation disinfection water supply pressure; the ozone generator (4212) and the gas flow controller (4211) are turned on, and the gas flow controller (4211) controls the ozone flow rate, so that ρ 臭氧 *N*M2 / M1 is equal to the set parameter of ozone concentration in the ozone mixture circulation disinfection process; this process circulates ozone into the stored filtered water in the finished product water tank (3); Once T4 duration is reached, shut down the equipment that was turned on during the ozone mixed liquid circulation disinfection process.

3. A method for pulse cleaning of a hollow fiber ultrafiltration membrane using an ozone-coordinated pulse cleaning system operating the cross-flow filtration internal pressure type hollow fiber ultrafiltration membrane as described in claim 1. Its features are, Including the following steps: Except for adjusting the forward washing step of the pulse cleaning method for the hollow fiber ultrafiltration membrane as described in claim 2, all other steps remain unchanged; the adjusted forward washing step is as follows: According to the quality of the filtered raw water and the design process of the hollow fiber ultrafiltration membrane (22), the parameters of the pulse inlet pressure at the bottom of the hollow fiber membrane during T1, T2 and the forward washing process are set. The water purification system remains off; Constant pressure water supply at the front end of the cleaning device: In the cleaning device (4), the gas-liquid mixing variable frequency booster pump (424) is turned on and constant pressure control is performed, that is, the parameter P3 is equal to the high value of the pulse water pressure at the bottom of the hollow fiber ultrafiltration membrane (22) during the forward washing process, and then the gas-liquid mixing variable frequency booster pump outputs stable power; the solenoid valve (b) and the electric valve (a) in the gas-liquid mixing branch (42) are closed; the solenoid valve (b) in the bypass pipeline (43) is turned on; the solenoid valve (b) in two or more forward washing branches (46) is turned on, the solenoid valve (b) in two or more backwash branches (47) is turned off, and the solenoid valve (b) in the bottom sewage branch (48) is turned off; Pulse water supply for cleaning device: In the pulse water supply branch (44), the electromagnetic overflow valve (441) is opened, and P4 is set to be equal to the parameter of the high value of the pulse water pressure at the lower end of the hollow fiber ultrafiltration membrane (22) during the forward washing process; the electromagnetic pressure reducing valve (442) is opened, and P5 is set so that (P4-P5)*F≤ the maximum pressure change value per unit time that the hollow fiber ultrafiltration membrane can withstand; any value of F is set in the range of 0.2~5, and the electromagnetic valve (b) in the pulse water supply branch (44) opens and closes at a frequency of F; This process removes the ozone mixture in the forward washing step of the pulse cleaning method for hollow fiber ultrafiltration membrane as described in claim 2, and uses the filtrate in the finished product water tank (3) as the cleaning medium for forward washing, while other processes remain unchanged.

4. A direct drinking water system comprising an ozone-assisted pulse cleaning system using a cross-flow filtration internal pressure hollow fiber ultrafiltration membrane as described in claim 1, characterized in that: The direct drinking water system also includes a pretreatment device (1), a water supply branch (5), and a return water branch (6); The pretreatment device (1) includes a municipal pipeline (11), a raw water tank (12), a raw water tank outlet booster pump (13), a quartz sand filter (14), an activated carbon filter (15), and a water supply precision filter (16) connected in sequence along the water flow direction. The electric valve (a) is provided at the connection between the municipal pipeline (11) and the raw water tank (12); The membrane treatment device (2) also includes a nanofiltration booster pump (28) and a nanofiltration unit (29). The intermediate water tank (26), the nanofiltration booster pump (28), and the nanofiltration unit (29) are connected in sequence by pipelines; The nanofiltration unit (29) has an outlet pipe connected to the finished water tank (3), and a solenoid valve (b) is installed at the outlet pipe. The water supply branch (5) includes a water supply frequency booster pump (51), a pressure sensor (c), and a water supply ultraviolet lamp (52). The finished water tank (3), the water supply frequency converter booster pump (51), the pressure sensor (c), and the water supply ultraviolet lamp (52) are connected in sequence by pipes; The return water branch (6) includes the electric valve (a), the return water ultraviolet lamp (61), and the return water precision filter (62). The electric valve (a), the return water ultraviolet lamp (61), and the return water precision filter (62) are connected in sequence by pipes; The outlet pipe of the return water precision filter (62) is connected to the inlet of the finished water tank (3).

Images