CN116924519A - Efficient automatic control method and system for immersed ultrafiltration membrane - Google Patents

Abstract

The invention discloses an efficient automatic control method and system for a submerged ultrafiltration membrane, which includes an ultrafiltration water production control program and a chemical cleaning control program; the ultrafiltration water production control program controls the incoming water of the ultrafiltration membrane pool to pass through the ultrafiltration membrane. When the water production pump is turned on to produce water, water passes through the ultrafiltration membrane and flows out from the inside; when chemical cleaning is performed, there will be different implementation procedures according to the type of cleaning agent and cleaning method. Chemical cleaning can The inorganic and organic substances attached to the ultrafiltration membrane are removed to restore the optimal water permeability of the ultrafiltration membrane. The water quality and quantity treated by this control method are stable, the ultrafiltration membrane has a long service life, the system recovery rate is high, the operating cost is low, and the degree of automation is high.

Description

An efficient automatic control method and system for immersed ultrafiltration membranes

Technical field

The invention belongs to the technical field of water treatment, and particularly relates to a full-process automatic control method and system for a submerged ultrafiltration membrane.

Background technique

Ultrafiltration is a membrane separation technology that can purify and separate solutions. Ultrafiltration membrane is an artificial filter membrane used in the ultrafiltration process. Generally made of polymer materials such as PVDF, PP, PS, etc. Ultrafiltration membrane is a solution separation device that uses ultrafiltration membrane wire as the filtration medium and the pressure difference on both sides of the membrane as the driving force. The ultrafiltration membrane only allows the solvent (such as water molecules), inorganic salts and dissolved organic matter in the solution to pass through, and intercepts suspended solids, colloids and microorganisms in the solution, thereby achieving the purpose of purification and separation. Ultrafiltration membranes are currently widely used in water treatment processes, and ultrafiltration technology plays an increasingly important role in reverse osmosis pretreatment, drinking water treatment, reclaimed water reuse and other fields.

The ultrafiltration membrane process has gradually been recognized and respected in the industry in recent years. The entire system includes ultrafiltration water production, physical cleaning, chemical cleaning, liquid preparation, liquid neutralization, waste liquid discharge and other sections. The ultrafiltration water production has an important impact on the system recovery rate. There are often higher requirements (equal to net water production/total water production). A high recovery rate indicates high system operating efficiency and low operating costs. Due to the continuous expansion of the scale of ultrafiltration, the improvement of workers' requirements for operating conditions and the pursuit of high efficiency in ultrafiltration processing, how to achieve efficient, stable and automated operation of the ultrafiltration system has become an urgent problem to be solved. However, there are currently very few results achieved in this regard domestically.

Contents of the invention

In order to solve the above problems, the present invention provides an efficient automatic control method and system that can improve the operation safety and processing efficiency of the submerged ultrafiltration membrane system and save operating costs.

In order to achieve the above goals, the present invention adopts the following technical solutions:

An efficient automatic control method for submerged ultrafiltration membranes, including:

Ultrafiltration water production control program: The incoming water of the ultrafiltration membrane pool flows in from the inlet canal. The inlet canal is equipped with a thermometer, liquid level meter, and turbidity meter to detect the quality and quantity of the incoming water respectively. The measured inlet water temperature can be analyzed Value, liquid level value and turbidity value set the membrane tank water flow rate accordingly. When the temperature value is lower than 15℃, the membrane tank water flow rate is reduced to 80% of the design flow rate. When it is higher than 15℃, For the design flow rate, when the liquid level is at 2m, increase the water flow rate of the membrane tank. When it is lower than 2m, adjust the water flow rate down. When the turbidity is higher than 5NTU, adjust the water flow rate down. When the turbidity is lower than 5NTU, increase it. Product water flow. The PLC controls the opening of the gate valve to adjust the inlet flow of the ultrafiltration membrane tank. The ultrafiltration membrane tank is equipped with a static pressure level gauge. The measurement value of the static pressure level gauge is used to determine whether to open the water production pump and whether to open the water inlet gate. Plate valve. When the membrane tank liquid level is lower than the L liquid level, the inlet gate valve opens. When the membrane tank liquid level is higher than the H liquid level, the inlet gate valve closes. When the membrane tank liquid level is higher than the L liquid level, the inlet gate valve closes. , the vacuum jet is turned on and closed for about 10-30 seconds, then the water production valve is opened, and then the water production pump is turned on, and the system begins to produce water. When the membrane tank liquid level is lower than the LL liquid level, the water production pump is closed, the water production valve is closed, and water production begins. At the end of the water program, when the system is running normally, the water production time is set according to a fixed period, usually 20-50 minutes, and the water production stops when the set period is reached. The LL liquid level is a protective liquid level to prevent damage to the ultrafiltration membrane due to drying and to prevent pump damage caused by empty pumping of the produced water pump. The L liquid level is the start liquid level of the ultrafiltration water produced, and the H liquid level is the water inlet stop liquid level to prevent the membrane from being damaged due to drying. Too much water entering the pool causes overflow.

Chemical cleaning control program: The outlet pipe of the ultrafiltration membrane pool is equipped with a pressure gauge. The measurement value of the pressure gauge can be used with the measurement value of the hydrostatic level gauge to calculate the transmembrane pressure difference of the ultrafiltration membrane. This value reflects the water permeability of the ultrafiltration membrane. It can determine whether the ultrafiltration membrane needs chemical cleaning. When the system is operating normally, the frequency of maintenance cleaning and restorative cleaning is set according to a fixed water production cycle. The transmembrane pressure difference is used as a reference value and protection value for ultrafiltration membrane cleaning. When the transmembrane pressure difference is 0-30KPa, it means that the ultrafiltration membrane has good water permeability. When the transmembrane pressure difference is 30-60KPa, maintenance cleaning is required. Restorative cleaning is required when the transmembrane pressure difference is 60-80KPa. When the transmembrane pressure difference is 80KPa and above, it is set as a protection value. That is, when this set value is reached, the PLC control system sends an alarm signal and stops water production. When performing chemical cleaning, there will be different implementation procedures depending on the type of cleaning agent and cleaning method. Chemical cleaning can remove inorganic and organic substances attached to the ultrafiltration membrane and restore the optimal water permeability of the ultrafiltration membrane.

Acid immersion washing: open the acid cleaning liquid inlet valve, open the acid cleaning liquid outlet valve, and then open the acid cleaning water pump. When the membrane tank liquid reaches the LL level, stop feeding, close the acid cleaning water pump, and then close the acid cleaning liquid inlet valve. Open the acid cleaning outlet valve. After the acid soak reaches the set time, if the number of reuses of the chemical solution has not reached the set number, open the chemical solution return valve, then open the acid solution return valve and acid cleaning inlet valve, and the chemical solution will flow back. Enter the acid cleaning pool, wait for the liquid reflux to be completed, close the liquid reflux valve, acid reflux valve and acid cleaning inlet valve, the acid soaking process is completed, enter the membrane tank rinsing and pipeline flushing process; if the number of times the chemical liquid is reused reaches Set the number of times, open the waste liquid discharge valve, and discharge the liquid into the neutralization tank. After the emptying is completed, close the waste liquid discharge valve. The acid soaking process is completed, and the membrane tank rinsing and pipeline flushing procedures are entered.

Or alkali immersion washing: open the alkali cleaning liquid inlet valve, open the alkali cleaning liquid outlet valve, and then open the alkali cleaning water pump. When the membrane tank liquid reaches the LL level, stop feeding, close the alkali cleaning water pump, and then close the alkali cleaning liquid inlet valve. and alkali cleaning liquid outlet valve. After the alkali soaking reaches the set time, if the number of times the chemical liquid is reused has not reached the set number, open the chemical liquid return valve, then open the alkali liquid return valve and alkali cleaning liquid inlet valve, and the chemical liquid will flow back. Enter the alkali cleaning pool. After the liquid reflux is completed, close the liquid reflux valve, alkali reflux valve and alkali cleaning inlet valve. The alkali soaking process is completed, and then enter the membrane tank rinsing and pipeline flushing process; if the chemical liquid is reused for Set the number of times, open the waste liquid discharge valve, and discharge the liquid into the neutralization tank. After the emptying is completed, close the waste liquid discharge valve. The alkali soaking process is completed, and the membrane tank rinsing and pipeline flushing processes are entered.

Membrane tank rinsing and pipeline flushing: Open the water inlet gate valve. When the membrane tank liquid level reaches the LL level, close the water inlet gate valve and open the cleaning cycle valve. When the cleaning is alkali cleaning, open the alkali cleaning outlet valve, and then Turn on the alkali cleaning water pump. When the cleaning is pickling, open the acid cleaning liquid outlet valve, and then turn on the acid cleaning water pump. The water in the membrane tank will circulate between the membrane tank, water production pipeline, chemical liquid return pipe and chemical inlet pipe. Rinse the membrane tank and flush the pipeline for about 2-10 minutes, then close the corresponding cleaning water pump, then close the cleaning circulation valve and the corresponding cleaning liquid outlet valve, open the waste liquid discharge valve, and discharge the rinse liquid into the neutralization tank until the membrane tank is emptied. After completion, close the waste liquid discharge valve. This is a membrane tank rinsing and pipeline flushing process, and then repeat the process once. After the membrane tank rinsing and pipeline flushing are completed, open the water inlet gate valve. When the membrane tank liquid level reaches L liquid level, the membrane tank enters normal water production state.

The membrane tank rinsing and pipeline flushing procedures are subsidiary procedures of the chemical cleaning control program. They are mainly to reduce the residual concentration of chemical cleaning agents in the membrane tank, and at the same time clean the water production pipeline, chemical feed pipeline and chemical liquid return pipe to ensure water production. water quality.

Furthermore, it also includes a physical cleaning control program: the ultrafiltration membrane is physically cleaned every time water is produced, that is, backwashing and air washing are performed at the same time. First, the ultrafiltration membrane tank performs liquid level drop filtration, closes the inlet gate valve, and the membrane tank Continue to produce water. When the membrane tank liquid level is lower than the LL level, the produced water pump is closed, the water production valve is closed, then the backwash valve is opened, then the backwash pump is opened, the air wash valve is opened at the same time, and then the Roots blower is opened, 50 -Turn off the backwash pump and Roots blower for 70 seconds, then close the backwash valve and air wash valve. After the physical cleaning is completed, open the water inlet gate valve and the system will enter the water production state again. After reaching the set number of physical cleanings, usually 3-6 times, open the wastewater discharge valve and discharge the backwash wastewater in the ultrafiltration membrane tank into the wastewater discharge tank. When the membrane tank is emptied, close the wastewater discharge valve and open Water inlet gate valve, the system then enters the water production process;

When the backwash wastewater of the physical cleaning control program is drained, close the wastewater discharge valve and then start the chemical cleaning control program.

Larger suspended solids, colloids, etc. are trapped on the outside of the ultrafiltration membrane. When the impurities on the outside of the ultrafiltration membrane accumulate to a certain extent, it will affect the water permeability of the ultrafiltration membrane. The physical cleaning frequency can be set according to the water quality and operating time, that is, reverse Washing and air washing are performed at the same time. The ultrafiltration membrane effluent is sent into the interior of the ultrafiltration membrane through the backwash pipe through the backwash pump. The water comes out from the inside of the ultrafiltration membrane. At the same time, the aeration fan is turned on to air scrub the ultrafiltration membrane. Some of the impurities attached to the ultrafiltration membrane are washed away to restore a certain degree of water permeability to the ultrafiltration membrane.

Furthermore, the chemical cleaning control program also includes acid cycle cleaning: open the acid cleaning inlet valve, open the acid cleaning outlet valve, and then open the acid cleaning water pump. When the membrane tank liquid reaches the LL level, open the cleaning circulation valve and close the acid. Clean the liquid inlet valve and start chemical liquid circulation washing. After the acid cycle reaches the set time, turn off the acid cleaning water pump, then close the cleaning circulation valve and acid cleaning outlet valve. If the number of times the chemical liquid is reused has not reached the set number, open The chemical liquid reflux valve, then open the acid liquid reflux valve and acid cleaning inlet valve, and the chemical liquid will flow back into the acid cleaning pool. After the chemical liquid reflux is completed, close the chemical liquid reflux valve, acid liquid reflux valve and acid cleaning inlet valve, and the acid will After the cycle program is completed, the membrane tank rinsing and pipeline flushing procedures are entered; if the number of times the chemical liquid is reused reaches the set number, the waste liquid discharge valve is opened and the liquid is discharged into the neutralization tank. After the emptying is completed, the waste liquid is closed. Discharge valve, the acid cycle process is completed, and the membrane tank rinsing and pipeline flushing processes are entered.

Alkali cycle cleaning: Open the alkali cleaning liquid inlet valve, open the alkali cleaning liquid outlet valve, and then open the alkali cleaning water pump. When the membrane tank liquid reaches the LL level, open the cleaning cycle valve, close the alkali cleaning liquid inlet valve, and start the liquid circulation. , after the alkali cycle reaches the set time, turn off the alkali cleaning water pump, then close the cleaning cycle valve and the alkali cleaning liquid outlet valve. If the number of reuses of the chemical solution has not reached the set number, open the chemical solution reflux valve, and then open the alkali solution reflux valve and alkali cleaning liquid inlet valve, the chemical liquid refluxes into the alkali cleaning pool. When the chemical liquid reflux is completed, close the chemical liquid reflux valve, alkali liquid reflux valve and alkali cleaning liquid inlet valve. The alkali cycle program is completed, and enters the membrane tank rinsing and pipeline Flushing process; if the number of reuses of the chemical solution reaches the set number, open the waste liquid discharge valve and discharge the chemical liquid into the neutralization tank. After the emptying is completed, close the waste liquid discharge valve and the alkali cycle program is completed and enters the membrane. Pool rinse and pipe flushing procedures.

Furthermore, it also includes a chemical liquid configuration control program: the chemical cleaning liquid is composed of the chemical liquid and the ultrafiltration produced water in a certain proportion. The chemical liquid is added to the corresponding chemical cleaning pool through a metering pump, and the chemical cleaning liquid is added according to the set flow rate and the concentration of the prepared chemical. Set the dosing time. The chemical cleaning pool is equipped with an alkali liquid level gauge and an acid liquid level gauge. Use the measured values of the alkali liquid level gauge and acid liquid level gauge to determine whether to turn on the water replenishment pump. Set the water replenishment level to 2.7 m, the water replenishment pump is turned on below this liquid level, and the water replenishment pump is turned off when it reaches this liquid level. The chemical cleaning pool is equipped with an alkali liquid thermometer, an acid liquid thermometer, an alkali liquid heater, and an acid liquid heater. The measurement value of the thermometer is used to determine whether to turn on the heating. The chemical cleaning agent is generally set at a temperature of 12-15 degrees Celsius or above. The agent stock solution tank includes a sodium hypochlorite stock solution tank, a sodium hydroxide stock solution tank, and a citric acid stock solution tank. The agent stock solution tank is equipped with a liquid level gauge. According to the liquid level measurement value, To determine whether it is necessary to replenish the pharmaceutical stock solution, the citric acid stock solution tank is equipped with a citric acid mixing agitator, which can stir and mix the citric acid solid. The chemical cleaning solution is prepared 2 hours before chemical cleaning, and 30% of the pharmaceutical stock solution is replenished in each cycle; Taking the acid cleaning solution as an example, open the citric acid dispensing valve, turn on the citric acid metering pump, add medicine to the acid cleaning pool according to the set flow rate and set time, then open the cleaning and replenishing valve, then open the cleaning and replenishing pump, and add acid to the cleaning tank. When the acid cleaning pool liquid level reaches the water replenishment level, stop replenishing water, close the cleaning water pump, and then close the cleaning water replenishment valve. When the citric acid stock solution reaches the dosing time, close the citric acid metering pump, then close the citric acid dispensing valve, and stop After the tonic and acid cleaning liquid preparation is completed, when the acid liquid thermometer shows that the temperature is lower than the set temperature value, turn on the acid liquid heater to heat the prepared cleaning liquid until the set temperature value.

Furthermore, it also includes a liquid neutralization control program: the neutralization tank is equipped with a pH meter and an ORP meter, which can detect the pH and redox properties of the waste liquid, and determine whether to turn on the metering pump based on its measured values. When the pH value is lower than the set value, When the set value is 6, the sodium hydroxide dosing pump is turned on. When the pH is higher than the set value of 9, the acid dosing pump is turned on. When the ORP value is 400mv higher than the set redox potential value, the reducing agent SBS dosing pump is turned on. , the neutralization tank is equipped with a pipeline mixer, which can fully mix the chemical liquid until the waste liquid in the neutralization tank reaches the discharge requirements, stop dosing, the neutralization control program is completed, and the waste liquid discharge control program is entered.

Further, it also includes waste liquid discharge control procedures: the waste pool and neutralization pool are equipped with waste pool level gauges and neutralization pool level gauges. The measurement values of the level gauges are used to determine whether to open the neutralization pool discharge pump and the waste pool. Discharge pump, in order to ensure enough reserved space for the neutralization tank and wastewater pool, the discharge pump is generally turned on for discharge when the liquid level reaches 1m.

Furthermore, the chemical cleaning of this automatic control system is divided into pickling and alkali cleaning according to the cleaning reagents. The pickling reagent is hydrochloric acid or citric acid, which mainly removes inorganic substances attached to the ultrafiltration membrane. The alkali cleaning reagents are sodium hypochlorite and sodium hydroxide. , mainly removes organic matter attached to the ultrafiltration membrane; according to the cleaning cycle, it is divided into maintenance cleaning and restorative cleaning. The maintenance cleaning cycle is shorter and is generally set to once every 1-30 days. The cleaning agent concentration is low and the acid concentration is low. Generally, it is 0.1%-0.5%. The alkali concentration is generally 0.1-0.5%. The cleaning time is short, usually 20-120 minutes. It mainly maintains the water permeability of the ultrafiltration membrane. The restorative cleaning cycle is longer, generally set to 3- Once every 12 months, the cleaning agent concentration is relatively high, the acid concentration is generally 0.5%-2%, the alkali concentration is generally 0.5-2%, and the cleaning time is longer, generally 4-24 hours, mainly to restore the optimal water permeability of the ultrafiltration membrane. The chemical concentration, cleaning cycle and time need to be determined according to the water quality; according to the cleaning method, it is divided into immersion cleaning and cycle cleaning. Immersion cleaning is a pure soaking of the ultrafiltration membrane in the cleaning liquid, and the cleaning liquid does not penetrate the ultrafiltration membrane. , the operating cost is low, and the cyclic cleaning is that the cleaning solution passes through the ultrafiltration membrane and then returns to the membrane tank for internal circulation, and the cleaning effect is better.

Furthermore, the chemical cleaning agent of this automatic control system uses a recycling and reuse program, which greatly saves operating costs. Each new chemical cleaning agent can be recycled and reused multiple times. It is generally set to 2-6 times, depending on the on-site cleaning. Effect settings.

Furthermore, this automatic control system adopts PLC control technology, uses cable connection, and uses a computer as the operating terminal. The working conditions of each part of the system, including ultrafiltration water production, physical cleaning, chemical cleaning, liquid preparation, etc., can be viewed on the system operation interface. Many parameters of chemical liquid neutralization, waste liquid discharge and other aspects can be set by the operator; this automatic control system has two modes: automatic control and manual control. Under automatic control, the system automatically operates according to preset parameters, and under manual control it can Control and adjust every link.

The ultrafiltration water production control program controls the water inlet and outlet through the ultrafiltration membrane, including water inlet channel, water inlet gate valve, ultrafiltration membrane tank, water production pump, flow meter, liquid level meter, etc.; the water inlet channel is equipped with a thermometer and liquid level Gauge and turbidity meter, an electric gate valve is installed at the inlet of the ultrafiltration membrane tank, and a static pressure level gauge is installed inside the ultrafiltration membrane tank; the water production pipeline of the ultrafiltration membrane tank is equipped with a pressure gauge, turbidity meter, etc.

The physical cleaning control program controls the ultrafiltration membrane to perform backwashing and air washing, including Roots blower, backwash pump, etc.

The chemical cleaning control program controls the ultrafiltration membrane to perform pickling, alkali cleaning and liquid circulation, including ultrafiltration membrane pool, chemical cleaning pool, cleaning water pump, liquid level gauge, etc.; the ultrafiltration membrane pool is connected to an acid cleaning water pump and an alkali cleaning water pump. , liquid medicine reflux valve; after the medicine liquid reflux valve, it is connected to the acid liquid feed valve and alkali liquid feed valve respectively through the acid liquid reflux valve and the alkali liquid reflux valve; the ultrafiltration membrane tank water production pipeline is connected to a cleaning circulation pipe, and is equipped with There is a cleaning cycle valve.

The chemical liquid preparation control program controls the dosage and concentration of the cleaning liquid, including chemical liquid tanks, metering pumps, flow meters, chemical cleaning pools, chemical cleaning pumps, water replenishment pumps, liquid level gauges, etc.

The liquid neutralization control program controls the pH and redox properties of the waste liquid in the neutralization tank, including the neutralization tank, pH meter, ORP meter, pharmaceutical stock solution tank, metering pump, etc.; the pharmaceutical stock liquid tank includes a sodium hypochlorite stock solution tank and a sodium hydroxide stock solution. Box, citric acid stock solution tank, the pharmaceutical stock solution tank is equipped with a liquid level gauge; the citric acid stock solution tank is equipped with a citric acid mixing agitator; the neutralization tank is equipped with a pipeline mixer.

The waste liquid discharge control program controls the liquid discharge from the waste pool and neutralization pool, including neutralization pool level gauge, neutralization pool discharge pump, waste pool level gauge, waste pool discharge pump, etc.

The main advantages of the high-efficiency automatic control method for immersed ultrafiltration membranes provided by the present invention are:

First, the automatic control method provided is designed to meet actual engineering applications. Each link is modified and improved during the long-term practical application process. The final result is a one-button operation for the entire system, and each link has automatic and manual gears. It is a fully efficient automated control system for immersed ultrafiltration membranes that has the distinct advantages of being optional and specific parameters can be adjusted at any time.

Second, the water recovery rate processed by this system is high, the water quality is stable, the ultrafiltration membrane has a long service life, the chemical cleaning agent has a high recycling rate, the system operating cost is greatly reduced, and the system is highly automated and can improve The immersed ultrafiltration membrane system has high processing efficiency, safety and labor saving.

Third, this system detects the transmembrane pressure difference in real time during the entire operation of the ultrafiltration membrane, and is equipped with a critical alarm device. It can perform physical and chemical cleaning of the ultrafiltration membrane in a timely and effective manner to ensure its optimal water permeability and effectively prolong the life of the ultrafiltration membrane. The service life of ultrafiltration membrane.

Fourth, the chemical cleaning liquid in this system adopts a recycling and reuse procedure, which results in a high system water recovery rate and low operating costs.

Description of the drawings

Figure 1 is a process flow chart 1 of the efficient automatic control method of the immersed ultrafiltration membrane of the present invention.

Figure 2 is the second process flow chart of the efficient automatic control method of the immersed ultrafiltration membrane of the present invention.

Figure 3 is a flow chart of the chemical cleaning process of the high-efficiency automatic control method of the immersed ultrafiltration membrane of the present invention.

Figure 4 is a flow chart of the waste liquid discharge process of the high-efficiency automatic control method of the immersed ultrafiltration membrane of the present invention.

In the picture, 1-thermometer, 2-liquid level gauge, 3-inlet water turbidity meter, 4-outlet water turbidity meter, 5-backwash pump, 6-cleaning water pump, 7-inlet gate valve, 8-inlet Air valve, 9-cleaning medicine inlet valve, 10-static liquid level gauge, 11-vacuum ejector, 12-pressure gauge, 13-backwash valve, 14-cleaning cycle valve, 15-water production valve, 16-super Filter product water pump, 17-chemical liquid return valve, 18-waste water discharge valve, 19-waste liquid discharge valve, 20-sodium hypochlorite original drug liquid level gauge, 21-sodium hypochlorite original liquid level meter, 22-sodium hydroxide original drug liquid level gauge, 23-Sodium hydroxide original solution tank, 24-Citric acid original drug liquid level gauge, 25-Citric acid original solution tank, 26-Citric acid mixing stirrer, 27-Alkali liquid replenishment valve, 28-Sodium hydroxide dispensing valve, 29- Alkali liquid level gauge, 30-lye thermometer, 31-lye heater, 32-lye drain valve, 33-alkali cleaning inlet valve, 34-lye return valve, 35-alkali cleaning water pump, 36- Sodium hypochlorite metering pump, 37-alkali mixing valve, 38-alkali cleaning outlet valve, 39-sodium hydroxide neutralization valve, 40-citric acid dispensing valve, 41-acid replenishing valve, 42-acid level gauge, 43-acid thermometer, 44-acid heater, 45-acid drain valve, 46-acid neutralization valve, 47-acid cleaning inlet valve, 48-acid reflux valve, 49-acid cleaning water pump, 50-sodium hydroxide metering pump, 51-acid mixing valve, 52-acid cleaning outlet valve, 53-citric acid metering pump, 54-PH meter, 55-neutralization tank level meter, 56-ORP meter, 57 -Neutralization pool discharge pump, 58-Wastewater pool liquid level gauge, 59-Wastewater pool discharge pump.

Detailed ways

In order to facilitate the understanding of those skilled in the art, the present invention will be further described below in conjunction with the embodiments and drawings.

As shown in Figures 1 to 4, they are the main process flow charts of the efficient automatic control method and system of this immersed ultrafiltration membrane. The process route is:

ⅠUltrafiltration water production control program

The incoming water of the ultrafiltration membrane pool flows in from the inlet canal. The inlet canal is equipped with a thermometer 1, a liquid level meter 2, an inlet water turbidity meter 3, and an outlet water turbidity meter 4. The quality and quantity of the incoming water are tested respectively, and the measured values can be measured by analyzing them. The inlet water temperature, liquid level and turbidity values are used to set the membrane tank water flow rate accordingly. When the temperature value is lower than 15°C, the membrane tank water flow rate is reduced to 80% of the design flow rate. When it is higher than At 15℃, it is the design flow rate. When the liquid level is 2m, increase the water flow rate of the membrane tank. When it is lower than 2m, adjust the water flow rate downward. When the turbidity is higher than 5NTU, adjust the water flow rate downward. When the turbidity is low, Increase the water production flow rate at 5NTU. An electric gate valve 7 is installed at the inlet of the ultrafiltration membrane tank. The opening of the gate valve is automatically controlled by PLC to adjust the inlet water flow of the ultrafiltration membrane tank. A hydrostatic liquid level gauge 10 is installed inside the ultrafiltration membrane tank. Through the static pressure liquid The measurement value of the level meter 10 determines whether to open the produced water pump 16 and whether to open the water inlet gate valve 7. When the membrane tank liquid level is lower than the L level, the water inlet gate valve 7 is opened. When the membrane tank liquid level is higher than the H liquid level, the water inlet gate valve 7 is opened. When the water inlet gate valve 7 is closed, when the membrane tank liquid level is higher than the L level, the vacuum ejector 11 is opened and closed for about 10-30 seconds, then the water production valve 15 is opened, and then the water production pump 16 is opened, and the system starts to produce water. , when the membrane tank liquid level is lower than the LL liquid level, the water production pump 16 is closed, the water production valve 15 is closed, and the water production program ends. During normal operation, the water production time is set according to a fixed period, usually 20-50 minutes. Water production stops when the set cycle is reached.

ⅡPhysical cleaning control program

The ultrafiltration membrane is physically cleaned every time water is produced, usually 20-50 minutes, that is, backwashing and air washing are performed at the same time. First, the ultrafiltration membrane tank is filtered with the liquid level falling, and the water inlet gate valve 7 is closed. The membrane tank continues to produce water. Water, when the liquid level of the membrane tank is lower than the LL level, the produced water pump 16 is closed, the produced water valve 15 is closed, then the backwash valve 13 is opened, then the backwash pump 5 is opened, and the air wash valve 8 is opened at the same time, and then the roots are opened fan, turn off the backwash pump 5 and the Roots blower for about 60 seconds, then close the backwash valve 13 and the air wash valve 8. After the physical cleaning is completed, open the water inlet gate valve 7, and the system will enter the water production state again. After each physical cleaning, The specific time depends on the water quality, usually 3-6 times. The backwash wastewater in the ultrafiltration membrane tank needs to be emptied, that is, open the wastewater discharge valve 18 and discharge it into the wastewater discharge tank. When the membrane tank is emptied, close the wastewater discharge. Valve 18, open the water inlet gate valve 7, and then the system enters the water production process.

ⅢChemical cleaning control program

The outlet pipe of the ultrafiltration membrane pool is equipped with a pressure gauge 12. The measurement value of the pressure gauge 12 can be used with the measurement value of the hydrostatic level gauge 10 to calculate the transmembrane pressure difference of the ultrafiltration membrane. This value reflects the water permeability of the ultrafiltration membrane and can be used to determine Whether the ultrafiltration membrane needs chemical cleaning, according to on-site debugging, the fixed cycle of maintenance cleaning and restorative cleaning can be set, and the transmembrane pressure difference value is used as the ultrafiltration membrane cleaning reference value and protection value. When performing chemical cleaning, there will be different implementation procedures depending on the type of cleaning agent and cleaning method, which are explained below:

① Acid soaking: After the backwash wastewater is drained, close the wastewater discharge valve 18, open the acid cleaning inlet valve 47, open the acid cleaning outlet valve 52, and then open the acid cleaning water pump 49. The membrane tank solution reaches the LL level. Stop feeding, turn off the acid cleaning water pump 49, then close the acid cleaning liquid inlet valve 47 and the acid cleaning liquid outlet valve 52. After the acid soaking reaches the set time, if the number of times the chemical liquid is reused has not reached the set number, open the chemical solution. Liquid reflux valve 17, then open the acid liquid reflux valve 48 and acid cleaning liquid inlet valve 47. The chemical liquid will flow back into the acid cleaning pool. When the chemical liquid reflux is completed, close the valves, the chemical liquid reflux valve 17, the acid liquid reflux valve 48 and the acid cleaning tank. Inlet valve 47, after the acid soaking process is completed, enter the membrane tank rinsing and pipeline flushing process; if the number of reuses of the chemical solution reaches the set number, open the discharge valve 19, and the chemical solution will be discharged into the neutralization tank until the emptying is completed. , then close the discharge valve 19, the acid soaking procedure is completed, and the membrane tank rinsing and pipeline flushing procedures are entered.

② Acid cycle washing: After the backwash wastewater is drained, close the wastewater discharge valve 18, open the acid cleaning inlet valve 47, open the acid cleaning outlet valve 52, and then open the acid cleaning water pump 49. The membrane tank solution reaches the LL level. When If the number of reuses of the chemical solution has not reached the set number, open the chemical solution return valve 17, then open the acid solution return valve 48 and the acid cleaning liquid inlet valve 47. The chemical solution will flow back into the acid cleaning pool. When the chemical solution reflux is completed, close the chemical solution. Return valve 17, acid return valve 48 and acid cleaning liquid inlet valve 47, the acid cycle program is completed, and the membrane tank rinsing and pipeline flushing program is entered; if the number of reuses of the chemical solution reaches the set number, the discharge valve 19 is opened, and the chemical solution is The liquid is discharged into the neutralization tank. After the emptying is completed, the discharge valve 19 is closed, the acid cycle program is completed, and the membrane tank rinsing and pipeline flushing procedures are entered.

③Alkali soaking wash: After the backwash wastewater is drained, close the wastewater discharge valve 18, open the alkali cleaning inlet valve 33, open the alkali cleaning outlet valve 38, and then open the alkali cleaning water pump 35, until the membrane tank liquid reaches the LL level Stop feeding the medicine, close the alkali cleaning water pump 35, and then close the alkali cleaning inlet valve 33 and the alkali cleaning outlet valve 38. After the alkali soaking reaches the set time, if the number of times the chemical liquid is reused has not reached the set number, open the medicine. Liquid reflux valve 17, then open the alkali liquid reflux valve 34 and alkali cleaning liquid inlet valve 33, and the chemical liquid will flow back into the alkali cleaning pool. After the liquid reflux is completed, close the chemical liquid reflux valve 17, alkali liquid reflux valve 34 and alkali cleaning inlet valve. Liquid valve 33, the alkali soaking process is completed, and the rinsing process is entered; if the number of times the chemical liquid is reused reaches the set number, the discharge valve 19 is opened, and the chemical liquid is discharged into the neutralization tank. After the emptying is completed, the discharge valve 19 is closed. , the alkali soaking procedure is completed, and the membrane tank rinsing and pipeline flushing procedures are entered.

④Alkali cycle washing: After the backwash wastewater is drained, close the wastewater discharge valve 18, open the alkali cleaning inlet valve 33, open the alkali cleaning outlet valve 38, and then open the alkali cleaning water pump 35, until the membrane tank liquid reaches the LL level When, open the circulation valve 14, close the alkali cleaning liquid inlet valve 33, and start the liquid circulation. After the alkali circulation reaches the set time, close the alkali cleaning water pump 35, then close the circulation valve 14 and the alkali cleaning liquid outlet valve 38. If the drug If the number of liquid reuses has not reached the set number, open the liquid medicine return valve 17, then open the alkali liquid return valve 34 and the alkali cleaning liquid inlet valve 33. The medicine liquid will flow back into the alkali cleaning pool. When the medicine liquid reflux is completed, close the valve medicine liquid. Return valve 17, alkali liquid return valve 34 and alkali cleaning liquid inlet valve 33, the alkali cycle program is completed and the rinsing program is entered; if the number of times the chemical liquid is reused reaches the set number, the discharge valve 19 is opened, and the chemical liquid is discharged into the neutralizer After the emptying is completed, the discharge valve 19 is closed, the alkali circulation program is completed, and the membrane tank rinsing and pipeline flushing procedures are entered.

Membrane tank rinsing and pipeline flushing: Open the inlet gate valve 7. When the membrane tank liquid level reaches the LL level, close the inlet gate valve 7, open the circulation valve 14, and open the alkali cleaning outlet valve 38 (after alkali cleaning) or Acid clean the liquid outlet valve 52 (after acid cleaning), and then open the alkali cleaning water pump 35 (after alkali cleaning) or the acid cleaning water pump 49 (after acid cleaning). The water in the membrane tank will circulate in the membrane tank, water production pipeline, chemical liquid return pipe and Internal circulation between the inlet pipes, rinsing the membrane pool and pipelines, the time is about 2-10 minutes, then close the corresponding cleaning water pump, then close the circulation valve and the corresponding cleaning inlet and outlet valve, open the discharge valve 19, and discharge the waste liquid into the neutralizer After the membrane tank is emptied, close the discharge valve 19, repeat the above operation once, and perform the membrane tank rinsing and pipeline flushing process twice; after the membrane tank rinsing and pipeline flushing are completed, open the water inlet gate valve 7, when the membrane tank When the liquid level reaches the L level, the membrane tank enters the ultrafiltration water production process.

The membrane tank rinsing and pipeline flushing procedures are subsidiary procedures of the chemical cleaning control program. They are mainly to reduce the residual concentration of chemical cleaning agents in the membrane tank, and at the same time clean the water production pipeline, chemical feed pipeline and chemical liquid return pipe to ensure water production. water quality.

ⅣMedicine liquid configuration control program

The chemical cleaning solution is composed of the original chemical solution and the ultrafiltration produced water in a certain proportion. The original chemical solution is added to the chemical cleaning pool through a metering pump. The metering pumps include: sodium hypochlorite metering pump 36, sodium hydroxide metering pump 50 or citric acid metering pump 53 .

The dosing time is set according to the set flow rate and the concentration of the prepared agent. The chemical cleaning pool is equipped with liquid level gauges 29 and 42. It is determined whether to open the water replenishing pump 6 based on the measured values of the liquid level gauges 29 and 42. The chemical cleaning pool is equipped with a thermometer 30. , 43 and heaters 31, 44. Use the measurement value of the thermometer to determine whether to turn on the heater. Generally, the temperature of the chemical cleaning agent is set to be above 12-15 degrees Celsius. The agent liquid tanks 21, 23, and 25 are equipped with liquid level gauges 20 and 22. , 24. According to the liquid level measurement value, it can be judged whether the liquid level needs to be replenished. When the liquid level is lower than 1m, the liquid level needs to be replenished. The liquid tank 25 is equipped with a mixer 26, which can stir and mix the citric acid solid. The chemical cleaning liquid configuration time is generally 2 hours before chemical cleaning, 30% of the chemical solution needs to be replenished for each cycle; taking the acid cleaning solution as an example, open the valve 40, turn on the citric acid metering pump 53, and add water to the acid cleaning pool according to the set flow rate and set time. medicine, at this time open the cleaning water replenishment valve 41, then open the cleaning water replenishment pump 6, replenish water to the acid cleaning pool, set the replenishment liquid level to 2.7m, when the acid cleaning pool liquid level reaches this level, stop water replenishment, and close the cleaning water pump 6 , then close the cleaning and replenishing valve 41. When the citric acid stock solution reaches the dosing time, close the citric acid metering pump 53, then close the valve 40 to stop dosing. The acid cleaning solution configuration is completed. When the thermometer 43 shows that the temperature is lower than the set temperature value , turn on the heater 44 to heat the cleaning fluid until the set temperature value.

ⅤMedicinal liquid neutralization control procedure

The neutralization tank is equipped with a PH meter 54 and an ORP meter 56, which can detect the pH and redox properties of the waste liquid, and use the measured values to determine whether to turn on the metering pump. When the pH value is lower than the set value, the alkali dosing pump is turned on. When the pH is higher than the set value, the acid dosing pump is turned on. When the ORP value is higher than a certain redox potential value, the reducing agent dosing pump is turned on. The neutralization tank is equipped with a pipeline mixer to fully mix the liquid. React until the waste liquid in the neutralization tank reaches the discharge requirements, stop dosing, the neutralization control program is completed, and the waste liquid discharge control program is entered.

ⅥWaste liquid discharge control procedures

The wastewater pool and the neutralization pool are equipped with a wastewater pool liquid level gauge 58 and a neutralization pool liquid level gauge 55. The measurement values of the liquid level gauges are used to determine whether to turn on the neutralization pool discharge pump 57 and the waste liquid pool discharge pump 59. In order to ensure neutralization Sufficient reserved space should be reserved for pools and wastewater pools. Generally, when the liquid level reaches a lower value, the discharge pump will be turned on for discharge.

The water treated by this system has a high recovery rate, stable water quality, long service life of the ultrafiltration membrane, high recycling rate of chemical cleaning agents, greatly reduced system operating costs, and the system has a high degree of automation, which can improve the immersion ultrafiltration process. The processing efficiency and safety of the membrane filter system save manpower.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the scope of the present invention. Anyone familiar with this technology can make various changes and decorations by applying the principles and technical features of the present invention. should be covered by the scope of protection defined by this claim.

Claims (9)

1. A high-efficiency automatic control method for immersed ultrafiltration membrane is characterized in that the method comprises the following steps,

ultrafiltration water production control program: inflow water of the ultrafiltration membrane pool flows in from a water inlet channel, a thermometer, a liquid level meter and a turbidity meter are arranged in the water inlet channel, the quality and quantity of inflow water are respectively detected, and the water flow rate of the membrane pool is set by analyzing the measured inflow water temperature value, liquid level value and turbidity value; a static pressure liquid level meter is arranged in the ultrafiltration membrane tank, and whether a water producing pump is started or not and whether a water inlet gate valve is started or not is judged according to the measured value of the static pressure liquid level meter;

when the liquid level of the membrane tank is lower than the L liquid level, the water inlet gate valve is opened;

when the liquid level of the membrane tank is higher than the H liquid level, the water inlet gate valve is closed, when the liquid level of the membrane tank is higher than the L liquid level, the vacuum ejector is opened, the water producing valve is closed for about 10-30s, then the water producing pump is opened, and the system starts to produce water;

when the liquid level of the membrane tank is lower than the LL liquid level, the water producing pump 16 is closed, the water producing valve 15 is closed, the water producing program is finished, and when the water inlet is stable, the water producing is stopped and set according to time;

chemical cleaning control procedure: the water outlet pipeline of the ultrafiltration membrane pool is provided with a pressure gauge, the measured value of the pressure gauge and the measured value of the static pressure liquid level meter can calculate the ultrafiltration membrane transmembrane pressure difference, and when the system normally operates, the maintenance cleaning frequency and the recovery cleaning frequency are set according to the fixed water production period;

acid soaking and washing: opening an acid liquor medicine inlet valve, opening an acid liquor medicine outlet valve, opening an acid cleaning water pump, stopping medicine feeding when the liquid medicine in the membrane tank reaches the LL liquid level, closing the acid cleaning water pump, closing the acid cleaning water inlet valve, opening an acid cleaning liquid outlet valve, and after acid soaking reaches a set time, if the repeated utilization times of the liquid medicine are less than the set times, opening a liquid medicine reflux valve, opening the acid liquor reflux valve and the acid cleaning liquid inlet valve, allowing the liquid medicine to reflux into an acid cleaning water tank, and after the liquid medicine reflux is completed, closing the liquid medicine reflux valve, the acid liquor reflux valve and the acid cleaning liquid inlet valve, completing an acid soaking program, and entering a membrane tank rinsing and pipeline flushing program; if the repeated utilization times of the liquid medicine reach the set times, opening a liquid waste discharge valve, discharging the liquid medicine into a neutralization tank, closing the liquid waste discharge valve after the liquid medicine is completely emptied, completing an acid soaking procedure, and entering a membrane tank rinsing and pipeline flushing procedure;

or alkali soaking and washing: opening an alkali cleaning liquid inlet valve, opening an alkali cleaning liquid outlet valve, opening an alkali cleaning water pump, stopping feeding medicine when the liquid medicine in the membrane tank reaches the LL liquid level, closing the alkali cleaning water pump, closing the alkali cleaning liquid inlet valve and the alkali cleaning liquid outlet valve, after alkali soaking reaches a set time, if the repeated utilization times of the liquid medicine are less than the set times, opening a liquid medicine reflux valve, opening an alkali liquid reflux valve and the alkali cleaning liquid inlet valve, allowing the liquid medicine to reflux into an alkali cleaning water tank, and after the liquid medicine is refluxed, closing the liquid medicine reflux valve, the alkali liquid reflux valve and the alkali liquid medicine inlet valve, completing an alkali soaking procedure, and entering a membrane tank rinsing and pipeline flushing procedure; if the repeated utilization times of the liquid medicine reach the set times, opening a liquid waste discharge valve, discharging the liquid medicine into a neutralization tank, closing the liquid waste discharge valve after the liquid medicine is completely emptied, completing an alkali soaking procedure, and entering a membrane tank rinsing and pipeline flushing procedure;

rinsing a membrane pool and flushing a pipeline: opening a water inlet gate valve, closing the water inlet gate valve when the liquid level of the membrane tank reaches the LL liquid level, opening a cleaning circulation valve, opening an alkali cleaning liquid outlet valve when cleaning is alkali cleaning, then opening an alkali cleaning water pump, opening an acid cleaning liquid outlet valve when cleaning is acid cleaning, then opening an acid cleaning water pump, flushing a pipeline for about 2-10min by inner circulation of water in the membrane tank between the membrane tank, a water production pipeline, a liquid medicine return pipe and a medicine inlet pipe, then closing a corresponding cleaning water pump, closing the cleaning circulation valve and a corresponding cleaning liquid outlet valve, opening a waste liquid discharge valve, discharging rinsing liquid into a neutralization tank, completing membrane tank emptying after the waste liquid discharge valve is closed, performing 2 times of membrane tank rinsing and pipeline flushing, and opening the water inlet gate valve when the liquid level of the membrane tank reaches the L liquid level, and the membrane tank enters a normal water production state.

2. The method for efficient and automatic control of an immersed ultrafiltration membrane according to claim 1, further comprising a physical cleaning control program:

the ultrafiltration membrane is subjected to physical cleaning for a certain time, namely backwash air washing is performed simultaneously, firstly, the ultrafiltration membrane tank is subjected to liquid level descending filtration, a water inlet gate valve is closed, the membrane tank is continuously subjected to water production, when the liquid level of the membrane tank is lower than the LL liquid level, a water production pump is closed, a water production valve is closed, then a backwash valve is opened, a backwash pump is opened, an air washing valve is opened, a Roots blower is opened, the backwash pump and the Roots blower are closed for 50-70 seconds, the backwash valve and the air washing valve are closed, the physical cleaning is finished, the water inlet gate valve is opened, and the system enters a water production state again;

after the physical cleaning is carried out for the set times, opening a wastewater discharge valve, discharging backwash wastewater in the ultrafiltration membrane tank into the wastewater discharge tank, closing the wastewater discharge valve after the membrane tank is emptied, opening a water inlet gate valve, and enabling the system to enter a water production program;

and after the backwash wastewater of the physical cleaning control program is emptied, closing the wastewater discharge valve and restarting the chemical cleaning control program.

3. The method for the efficient and automatic control of an immersed ultrafiltration membrane according to claim 1, wherein,

the chemical cleaning control program also comprises acid circulation cleaning: opening an acid cleaning liquid inlet valve, opening an acid cleaning liquid outlet valve, opening an acid cleaning water pump, opening a cleaning circulation valve when the liquid medicine in the membrane tank reaches the LL liquid level, closing the acid cleaning liquid inlet valve, starting the liquid medicine circulation cleaning, closing the acid cleaning water pump after the acid circulation reaches the set time, closing the cleaning circulation valve and the acid cleaning liquid outlet valve, opening a liquid medicine reflux valve if the liquid medicine recycling times are less than the set times, opening an acid liquid reflux valve and an acid cleaning liquid inlet valve, enabling the liquid medicine to reflux into an acid cleaning water tank, closing the liquid medicine reflux valve, the acid liquid reflux valve and the acid cleaning liquid inlet valve when the liquid medicine reflux is completed, completing an acid circulation program, and entering a membrane tank rinsing and pipeline flushing program; if the repeated utilization times of the liquid medicine reach the set times, opening a liquid waste discharge valve, discharging the liquid medicine into a neutralization tank, closing the liquid waste discharge valve after the liquid medicine is completely emptied, completing an acid circulation procedure, and entering a membrane tank rinsing and pipeline flushing procedure;

alkali circulation washing: opening an alkali cleaning liquid inlet valve, opening an alkali cleaning liquid outlet valve, opening an alkali cleaning water pump, opening a cleaning circulation valve when the liquid medicine in the membrane tank reaches the LL liquid level, closing the alkali cleaning liquid inlet valve, starting the liquid medicine circulation, closing the alkali cleaning water pump after the alkali circulation reaches the set time, closing the cleaning circulation valve and the alkali cleaning liquid outlet valve, opening a liquid medicine reflux valve and the alkali cleaning liquid inlet valve if the liquid medicine recycling times are less than the set times, opening the liquid medicine reflux valve and the alkali cleaning liquid inlet valve, allowing the liquid medicine to flow back into an alkali cleaning water tank, closing the liquid medicine reflux valve, the liquid medicine reflux valve and the alkali cleaning liquid inlet valve after the liquid medicine is refluxed, completing an alkali circulation procedure, and entering a membrane tank rinsing and pipeline flushing procedure; if the repeated utilization times of the liquid medicine reach the set times, opening a liquid waste discharge valve, discharging the liquid medicine into a neutralization tank, closing the liquid waste discharge valve after the liquid medicine is completely emptied, completing an alkali circulation procedure, and entering a membrane tank rinsing and pipeline flushing procedure.

4. The method for the efficient and automatic control of an immersed ultrafiltration membrane according to claim 1, further comprising a liquid medicine configuration control program:

adding the chemical raw liquid into a chemical cleaning water tank through a metering pump, setting the dosing time according to the set flow and the concentration of the dosing agent, judging whether to start a water supplementing pump or not through the measured values of the alkali liquid level meter and the acid liquid level meter, and starting the alkali liquid heater and the acid liquid heater if the measured values of the alkali liquid thermometer or the acid liquid thermometer are not higher than 12-15 ℃;

the liquid level meter is arranged on the chemical agent stock solution tank, whether the chemical agent stock solution is required to be replenished can be judged according to the liquid level measurement value, the citric acid stock solution tank in the chemical agent stock solution tank is provided with the citric acid mixing stirrer which is used for stirring and mixing citric acid solids, the chemical cleaning liquid is configured 2 hours before chemical cleaning, and the chemical agent stock solution is replenished by 30% in each cycle of liquid medicine.

5. The method for the efficient and automatic control of an immersed ultrafiltration membrane according to claim 1, further comprising a liquid medicine neutralization control program:

the neutralization tank is provided with a pH meter and an ORP meter, whether a metering pump is started is judged through a measured value, when the pH value is lower than a set value, a sodium hydroxide dosing pump is started, when the pH value is higher than the set value, an acid dosing pump is started, when the ORP value is higher than a certain oxidation-reduction potential value, a reducing agent dosing pump is started, a pipeline mixer of the neutralization tank carries out full mixing reaction on the liquid medicine until the waste liquid of the neutralization tank reaches the discharge requirement, dosing is stopped, and the neutralization control procedure is completed.

6. The method for efficient and automatic control of an immersed ultrafiltration membrane according to claim 5, further comprising a waste liquid discharge control program: the wastewater tank and the neutralization tank are provided with a wastewater tank liquid level meter and a neutralization tank liquid level meter, and when the liquid level reaches a lower value, a neutralization tank discharge pump and a wastewater tank discharge pump are started for discharge.

7. The method for the efficient and automatic control of an immersed ultrafiltration membrane according to claim 1, wherein,

the cleaning period is divided into maintenance cleaning and recovery cleaning, wherein the maintenance cleaning is carried out once in 1-30 days, the acid concentration of the cleaning agent is generally 0.1-0.5%, the alkali concentration is generally 0.1-0.5%, and the cleaning time is 20-120 minutes; the restorative cleaning cycle is set to be 3-12 months, the acid concentration of the cleaning agent is generally 0.5-2%, the alkali concentration is generally 0.5-2%, and the cleaning time is 4-24 hours.

8. The efficient and automatic control method for an immersed ultrafiltration membrane according to claim 1, wherein: the computer is used as an operation terminal, two modes of automatic control and manual control are provided, the automatic control automatically operates according to preset parameters, and the manual control can adjust links of ultrafiltration water production, physical cleaning, chemical cleaning, liquid medicine configuration, liquid medicine neutralization and waste liquid discharge.

9. A system for applying the efficient automatic control method of the immersed ultrafiltration membrane according to any one of claims 1 to 8, characterized in that:

the ultrafiltration water production control program controls water inflow and water outflow through an ultrafiltration membrane, and comprises a water inflow channel, a water inflow gate valve, an ultrafiltration membrane pool, a water production pump, a flowmeter and a liquid level meter; the inlet canal is provided with a thermometer, a liquid level meter and a turbidity meter, an electric gate valve is arranged at the inlet of the ultrafiltration membrane tank, and a static pressure liquid level meter is arranged in the ultrafiltration membrane tank;

the physical cleaning control program controls the ultrafiltration membrane to carry out backwashing and air washing, and the physical cleaning control program comprises a Roots blower and a backwashing water pump;

the chemical cleaning control program controls the ultrafiltration membrane to carry out acid washing, alkali washing and liquid medicine circulation, and comprises an ultrafiltration membrane tank, a chemical cleaning pump and a liquid level meter; the water outlet pipeline of the ultrafiltration membrane pool is provided with a pressure gauge; the ultrafiltration membrane pool is connected with an acid cleaning water pump, an alkali cleaning water pump and a liquid medicine reflux valve; the liquid medicine reflux valve is communicated with the acid cleaning liquid inlet valve and the alkali cleaning liquid inlet valve through the acid liquid reflux valve and the alkali liquid reflux valve respectively; a cleaning circulation valve is also arranged in the ultrafiltration membrane tank;

the liquid medicine preparation control program controls the dosage and concentration of the cleaning liquid medicine, and comprises a liquid medicine raw material tank, a metering pump, a flowmeter, a chemical cleaning tank, a chemical cleaning pump, a water supplementing pump and a liquid level meter;

the liquid medicine neutralization control program controls the pH value and the redox of the waste liquid of the neutralization tank, including the neutralization tank, a pH meter, an ORP meter, a medicament stock solution tank, a metering pump and the like; the reagent raw liquid tank comprises a sodium hypochlorite raw liquid tank, a sodium hydroxide raw liquid tank and a citric acid raw liquid tank, and a liquid level meter is arranged on the reagent raw liquid tank; the citric acid stock solution tank is provided with a citric acid mixing stirrer; the neutralization tank is provided with a pipeline mixer;

the waste liquid discharge control program controls the liquid discharge of the waste water tank and the neutralization tank, and comprises a neutralization tank liquid level meter, a neutralization tank discharge pump, a waste water tank liquid level meter and a waste water tank discharge pump.