Micro-flocculation-ultrafiltration reactor capable of flexibly coping with change of high-turbidity water in rainstorm period and use method of micro-flocculation-ultrafiltration reactor

Abstract

The invention discloses a micro-flocculation-ultrafiltration reactor capable of flexibly coping with high-turbidity water change in a rainstorm period, which comprises a clean water tank, the clean water tank is connected with an ultrafiltration water outlet pipe, the ultrafiltration water outlet pipe is connected with a plurality of hollow fiber membrane modules, the bottoms of the hollow fiber membrane modules are connected with an ultrafiltration water inlet, the ultrafiltration water inlet is connected with an ultrafiltration water inlet pipe, and the ultrafiltration water inlet pipe is connected with a water outlet pipe. A mixing unit body is arranged on the ultrafiltration water inlet pipe, a dosing device is arranged on one side of the mixing unit body, a first turbidimeter and a first electromagnetic valve are arranged at the front end of the ultrafiltration water inlet pipe, a water level gauge is arranged in the clean water tank and is in signal connection with a controller, and the controller is in signal connection with the first electromagnetic valve and the dosing device. By controlling the electromagnetic valve, the whole device can form a continuous flow system, and compared with the existing rural drinking water treatment equipment, the process flow is simpler, the operation management is more convenient, and the service life of the membrane is greatly prolonged.

Description

Technical Field

[0001] The invention relates to a micro-flocculation-ultrafiltration reactor capable of flexibly coping with changes in highly turbid water during a rainstorm period and a use method thereof, and belongs to the field of water treatment. Background Art

[0002] In recent years, with the support of national policies, local governments have focused on building rural water supply projects. However, due to the complexity of topography, landform, climate, economic and social conditions in rural areas, there are many problems, such as water shortage, poor water quality, and poor management. Among them, the treatment of high turbidity water formed during heavy rainfall has become the most prominent problem. Due to the dispersed population distribution in rural areas, the small scale of water supply projects, the low level of management and maintenance, and the lack of effective management mechanisms and financial support for water supply projects in some areas, rural water supply projects generally have problems such as high operating costs and low returns. Therefore, choosing an intelligent water purification process that can control operating costs, improve economic benefits, and coordinate the control of the entire water production process is the key to ensuring that rural water supply projects with a wide range of areas and large volumes can benefit the people for a long time.

[0003] The conventional water treatment process for modern drinking water is: coagulation-sedimentation-filtration-disinfection. By adding coagulants, impurities in the water are removed through coagulation precipitation reaction and filtration. Although the conventional drinking water treatment process has a good water quality treatment effect and can effectively remove colloids, particulate matter, bacteria and E. coli in the raw water, it also has its limitations. First, the conventional water treatment process has a poor ability to remove organic matter in water. Increasing the amount of coagulant added can improve the treatment effect of organic matter, but it will increase the cost of water treatment and may increase the concentration of metal ions in water, threatening human health; second, the disinfection unit of the conventional water treatment process will produce toxic and harmful disinfection by-products. The natural organic matter in natural water bodies has a complex structure. During the disinfection process, the strong oxidizing disinfectant can kill microorganisms in the water while reacting with natural organic matter, bromide, iodide, etc. in the raw water to generate various disinfection by-products; third, when the conventional water treatment process treats low-temperature and low-turbidity water, increasing the amount of reagents added is difficult to achieve the ideal effect, and it will also cause the turbidity of the effluent to increase, and fail to meet the corresponding effluent water quality requirements.

[0004] As the third generation of drinking water treatment technology, membrane treatment technology has the advantages of stable water quality, small footprint, high efficiency and flexibility, and low production of harmful by-products. In rural water supply, ultrafiltration membrane treatment processes are widely used. This is mainly because rural water sources usually contain high turbidity, suspended matter and microorganisms, especially during heavy rains, the concentration of the above pollutants surges. Compared with nanofiltration and reverse osmosis, ultrafiltration can effectively remove these large molecular pollutants and is more suitable for treating such water sources. In addition, ultrafiltration has a lower operating cost. Ultrafiltration technology is relatively mature and easy to operate. Ultrafiltration can meet the basic needs of rural residents for water quality. There is no need to use more complex and expensive nanofiltration or reverse osmosis technology. It is more suitable for the operation and maintenance conditions in rural areas, and the maintenance cost and energy consumption are more economical. However, when dealing with highly turbid water during heavy rainfall periods, single ultrafiltration technology can easily lead to membrane contamination, thus affecting flux stability and requiring frequent cleaning or replacement of membrane elements. This will also increase operating costs and energy consumption. Therefore, it is necessary to select a suitable pretreatment process before ultrafiltration, which will help reduce the particulate and organic load entering the ultrafiltration membrane, reduce the risk of membrane clogging, and improve the stability and operating efficiency of the ultrafiltration system, thereby extending the service life of the ultrafiltration membrane elements and reducing operating costs.

[0005] At present, the commonly used technologies for rural water supply include coagulation sedimentation-membrane filtration, ozone oxidation-sand filtration, and ultraviolet disinfection-activated carbon filtration. Among them, coagulation sedimentation requires a long sedimentation time and a large area. In addition, since the highly turbid water during the rainstorm period contains a large amount of suspended matter, it will weaken the oxidation effect of ozone, affect the ultraviolet penetration rate, and may cause the activated carbon to saturate quickly, thus requiring frequent replacement.

[0006] In view of the above problems, on the basis of the conventional treatment process mechanism, a micro-flocculation enhancement process has been developed through further research. Micro-flocculation adds an appropriate amount of flocculant to water to aggregate particles or suspended particles in the water to form micro-flocs, accelerate the aggregation of particles in the water, so as to remove suspended matter in the water and reduce the load for subsequent water treatment. Since the precipitation equipment is omitted, the micro-flocculation process occupies a small area, and only micro-flocs are produced during the reaction process, so the investment cost and operating cost are generally low, and the water purification efficiency is high. In the micro-flocculation process, an agitator is usually used to stir the water, but the mixing effect of water and flocculant is poor, the micro-flocculation reaction is not sufficient, and the flocculation effect is affected. The present invention studies a tubular mixer that selects a water treatment method according to the water quality and adjusts the dosage of the metering pump to form good micro-flocs. The micro-flocs show stable flocculation performance, do not require too long a sedimentation time to complete the aggregation of particles, and are not easy to decompose or break.

[0007] In order to achieve real-time monitoring and adjustment of water quality, enhance the system's responsiveness, reliability and stability, and reduce the risk of failure, it is proposed to link the microflocculation reactor with the subsequent membrane system and the clear water tank to form a closed-loop control, thereby improving the level of automation and solving the problem of low operation and management levels of rural technicians. At present, integrated water purification process facilities are common in large water plants. The water purification process is complicated, and there are delays in the real-time data processing of the intelligent system, which can easily lead to failures when the system is highly integrated, which may affect the overall operation. Summary of the invention

[0008] Purpose of the invention: In order to overcome the deficiencies in the prior art, the present invention provides a micro-flocculation-ultrafiltration reactor and a method of use that can flexibly respond to changes in high turbidity water during rainstorms. By controlling the solenoid valve, the entire device can be formed into a continuous flow system. Compared with existing rural drinking water treatment equipment, the process flow is simpler, the operation and management are more convenient, and the membrane operating life is greatly improved.

[0009] Technical solution: To solve the above technical problems, the present invention provides a micro-flocculation-ultrafiltration reactor that can flexibly respond to changes in high turbidity water during rainstorms, including a clear water tank, the clear water tank is connected to an ultrafiltration outlet pipe, the ultrafiltration outlet pipe is connected to a plurality of hollow fiber membrane modules, the bottom of the hollow fiber membrane module is connected to an ultrafiltration water inlet, the ultrafiltration water inlet is connected to an ultrafiltration water inlet pipe, a mixing unit is provided on the ultrafiltration water inlet pipe, a dosing device is provided on one side of the mixing unit, a first turbidity meter and a first solenoid valve are provided at the front end of the ultrafiltration water inlet pipe, a water level meter is provided in the clear water tank, the water level meter is connected to a controller signal, and the controller is connected to the first solenoid valve signal and the dosing device signal.

[0010] Preferably, the dosing device comprises a medicine storage tank, a screw conveyor, a metering pump and a dosing pipe. A solenoid valve and a metering pump are provided under the medicine storage tank. The solenoid valve is connected to the screw conveyor, and the screw conveyor is connected to the dosing pipe. The dosing pipe delivers the medicine to be added into the ultrafiltration water inlet pipe. The second solenoid valve and the metering pump are connected to the controller signal.

[0011] Preferably, the mixing unit body is composed of rotating blades or spirals, and both ends of the mixing unit body are connected to the ultrafiltration water inlet pipe through flanges.

[0012] Preferably, a backwash device is provided between the clean water tank and the hollow fiber membrane assembly, the backwash device comprises a backwash pump backwash pipe, one end of the backwash pipe is connected to the bottom of the clean water tank, and the other end is connected to the top of the hollow fiber membrane assembly, and a backwash valve and a backwash pump are provided on the backwash pipe.

[0013] Preferably, a second turbidity meter and a circulation inlet are provided between the mixing unit and the ultrafiltration water inlet, a third solenoid valve is provided at the front end of the ultrafiltration water inlet, the circulation inlet is connected to the circulation pipe, the circulation outlet is located between the first solenoid valve and the dosing device, the circulation pipe is connected to the circulation outlet, and the third solenoid valve is connected to the controller signal.

[0014] A method for using a microflocculation-ultrafiltration reactor that flexibly responds to changes in high turbidity water during a rainstorm period comprises the following steps: (1) Connect the above structures as required, set the water level threshold of the clean water tank and the turbidity threshold of the ultrafiltration inlet pipe; (2) When rainfall occurs, the controller reads the values ​​of the first turbidity meter and the water level meter. When the water level in the clean water tank exceeds the threshold, the controller controls the first solenoid valve to close. When the water level in the clean water tank is lower than the threshold, the controller reads the value X of the first turbidity meter. When the turbidity of the inlet water reaches 40 NTU, the second solenoid valve is started. The dosing amount of the dosing device is Q, Q=0.00035(X-40)+0.1, X is the turbidity, the unit is NTU, and the controller reads the value of the second turbidity meter in real time. When the value of the second turbidity meter is higher than 15.0 NTU, the third solenoid valve is closed and the circulating water pipe is opened. When the value of the second turbidity meter is lower than 15.0 NTU, the third solenoid valve is opened and the water enters the hollow fiber membrane module for further treatment, and finally obtains daily drinking water that meets the standards.

[0015] In the present invention, a medicine storage tank, a metering pump, a medicine adding pipeline and a numerical control system are arranged in the medicine adding system. The first medicine adding pipeline is connected to the medicine storage tank, and the medicine storage tank is connected to the metering pump. The metering pump is connected to the medicine adding port at the upper end of the micro-flocculation mixer through the second medicine adding pipeline. The front end of the micro-flocculation mixer is connected to the first water inlet pipe. The numerical control system is connected to the turbidity online monitoring system through digital signals, and the pipeline is controlled to be on and off through the first electromagnetic valve. The ultrafiltration membrane system is composed of an inlet and outlet pipe, a sewage pipe and a hollow fiber membrane assembly. The outlet pipe is connected to the water inlet pipe of the clear water tank. The turbidity online monitoring system includes a turbidity meter probe and a turbidity online analyzer. The turbidity meter probe is connected to the pipeline through the reserved port at the front end of the raw water inlet pipe. The turbidity data changes are monitored in real time by a sensor and transmitted to the turbidity online analyzer. The corresponding dosage of the agent is determined after analysis by a big data algorithm.

[0016] An insulation layer is arranged outside the medicine storage tank and the medicine dosing pipeline to prevent the medicine from getting damp. The upper part of the first medicine dosing pipeline is connected to the bottom of the medicine storage tank, and a second electromagnetic valve is installed therebetween. A screw conveyor is installed at the discharge port of the medicine storage tank, and a conveying blade is arranged inside the medicine dosing pipeline. The screw conveyor is connected to the conveying blade, and one end of the conveyor is connected to the first motor. The lower end of the first medicine dosing pipeline is connected to the inlet of the metering pump, and one end of the metering pump is connected to the second motor. The outlet of the metering pump is connected to the upper part of the second medicine dosing pipeline, and the medicine is transported to the micro-flocculation mixer through the blades in the pipeline.

[0017] The turbidity analyzer converts the real-time turbidity data into digital signals and transmits them to the CNC system, which controls the on-off of the raw water pipeline through the first electromagnetic valve. When the dosing system is turned on, the dosage of the agent is determined by the set dosage calculation formula, and the on-off of the second electromagnetic valve is controlled to add the agent. A level sensor is installed inside the drug storage tank, which converts the dosage change of the agent into a digital signal and transmits it to the CNC system, thereby controlling the opening and closing time of the second electromagnetic valve to add the appropriate amount of agent. The agent is transported to the metering pump, which can be a diaphragm pump or a plunger pump, and the agent is accurately added by controlling the movement of the pump's piston or diaphragm. The dosing pipe is usually made of corrosion-resistant materials such as stainless steel.

[0018] A mixing unit, a seal and a supporting structure for stabilizing and fixing the mixer are arranged inside the micro-flocculation mixer. The mixing unit is composed of rotating blades or spirals, both of which are made of stainless steel. Both ends of the mixer are connected to the raw water inlet pipe through flanges.

[0019] The ultrafiltration membrane system is connected to the micro-flocculation mixer through the second water inlet pipe, and then connected to the water inlet of the hollow fiber membrane module. The water outlet of the hollow fiber membrane module is connected to the clean water tank through the outlet pipe, and the pipeline is controlled by the fourth electromagnetic valve. A backwashing device is set in the ultrafiltration membrane system. The backwashing cycle is set by the program to clean the membrane pollutants adsorbed in the hollow fiber membrane module. There is no need to design hydraulic cleaning and chemical cleaning devices separately to achieve continuous water discharge. The hollow fiber membrane module adopts an immersed membrane module, the ultrafiltration membrane material is polyvinylidene fluoride, and the filtration method adopts external pressure filtration.

[0020] A water level sensor is installed in the clean water tank. When the water level is lower than the set critical value, the signal is automatically transmitted to the CNC system. The dosing system is opened and closed according to the real-time turbidity data. The first solenoid valve and the second solenoid valve are opened at the same time to produce water through the ultrafiltration membrane system.

[0021] By using a micro-flocculation-ultrafiltration reactor that can flexibly respond to changes in high turbidity water during rainstorms, the dosage of the reagent can be monitored in real time and flexibly adjusted for surface water with turbidity changes during rainfall / non-rainfall periods, which can effectively save manpower and resource costs.

[0022] The micro-flocculation-ultrafiltration reactor of the present invention can form a continuous flow system for the entire device by controlling the electric valve through the electric control system. Compared with the existing rural drinking water treatment equipment, the process flow is simpler, the operation and management are more convenient, and the membrane operation life is greatly improved.

[0023] All pipelines in the present invention are made of stainless steel.

[0024] In the first step, when the inlet turbidity reaches 40 NTU, the dosing system is started, and the dosing amount is controlled by the metering pump flow rate. When started, the flow rate of 10% polyaluminium chloride changes to 0.1 L / h. During non-rainfall periods, when the raw water inlet turbidity is lower than 40 NTU, the water quality is excellent, and the turbidity data is uploaded to the turbidity analyzer. The conditions for triggering the electronic control system to control the dosing are not met, and the dosing system remains closed. At the same time, the electronic control system controls the electric valve to open, and the raw water to be treated is introduced to form a continuous flow system and then flows into the ultrafiltration membrane unit through the microflocculation tubular mixer for treatment. This process does not require the addition of drugs, and the treated clean water is stably stored in the clean water tank to ensure the stability of the water supply. In addition, a backup water source is provided to respond to emergencies; The second step is that during the rainfall period, the turbidity of the raw water surges. When the turbidity is higher than 40 NTU, if there is sufficient water in the clean water tank, the water volume sensor transmits data to the central control system, controls the closing of the electric valve to prevent the raw water washed by the rainstorm from entering the tubular mixer, and at the same time closes the dosing system and the ultrafiltration membrane treatment system to avoid water quality changes and turbidity problems that may be caused during the rainstorm. Residents use water directly in the clean water tank to ensure the stability of the quality of residents' water and effectively reduce the energy consumption and operating costs of the water supply system; The third step is that during rainfall, the turbidity of the raw water increases sharply. When the turbidity is higher than 40 NTU, if there is insufficient water in the clear water tank, the water volume sensor transmits data to the central control system, controls the opening of the electric valve, and introduces the raw water to be treated to form a continuous flow system. At the same time, the dosing system is turned on. The central control system accurately evaluates the water quality based on the real-time data obtained from the turbidity analyzer on the cloud, and dynamically adjusts the dosage of the agent based on the linear relationship between turbidity and dosage. The flocculant is sent from the drug storage tank to the metering pump through the screw conveyor, and then enters the micro-flocculation reactor through the dosing pipe. Under the action of the mixing unit, the agent and the water flow are fully mixed and uniformly formed, and micro-flocculations with irregular shapes, certain surface roughness and diameters ranging from a few microns to hundreds of microns are quickly formed. The formed micro-flocculations are not easy to break and can effectively condense impurities and microorganisms suspended in the water. The raw water after micro-flocculation pretreatment then enters the ultrafiltration membrane system for treatment to further ensure the safety and health of the effluent. The turbidity of the ultrafiltration effluent is below 1.0 NTU, organic matter is basically removed, and the water quality is further improved, meeting the standard requirements for daily drinking water for residents.

[0025] A micro-flocculation-ultrafiltration reactor which can flexibly cope with the change of high turbidity water during rainstorm period comprises an online turbidity monitoring system, a dosing system, a micro-flocculation mixer and an ultrafiltration membrane system, wherein the online turbidity monitoring system is connected with a first water inlet pipe, the first water inlet pipe is controlled by a first electromagnetic valve, a drug storage tank, a metering pump, a dosing pipeline and a numerical control system are arranged in the dosing system, the first dosing pipeline is connected with the drug storage tank, and the drug storage tank is communicated with the metering pump, the metering pump is connected with the dosing port at the upper end of the micro-flocculation mixer through a second dosing pipeline, the front end of the micro-flocculation mixer is connected with the first water inlet pipe, the numerical control system is connected with the online turbidity monitoring system through a digital signal, and the on-off of the pipeline is controlled by the first electromagnetic valve, the ultrafiltration membrane system consists of an inlet and outlet pipe, a sewage pipe and a hollow fiber membrane assembly, and the outlet pipe is connected with the inlet pipe of a clear water tank.

[0026] Furthermore, the turbidity online monitoring system includes a turbidity meter probe and a turbidity online analyzer. The turbidity meter probe is connected to the pipeline through a reserved port at the front end of the raw water inlet pipe. The sensor monitors the turbidity data changes in real time and transmits them to the turbidity online analyzer.

[0027] Furthermore, the turbidity analyzer converts the real-time turbidity data into digital signals and transmits them to the CNC system, which controls the opening and closing of the raw water pipeline through the first electromagnetic valve. When the dosing system is turned on, the dosage of the agent is determined by the set dosage calculation formula, and the second electromagnetic valve is controlled to open and add the agent. A level sensor is installed inside the drug storage tank, which converts the change in the dosage of the agent into a digital signal and transmits it to the CNC system, thereby controlling the opening and closing time of the second electromagnetic valve to add the appropriate amount of agent, and the agent is transported to the metering pump for further accurate dosing of the agent.

[0028] Furthermore, a mixing unit, a seal and a supporting structure for stabilizing and fixing the mixer are arranged inside the micro-flocculation mixer, and both ends of the mixer are connected to the first water inlet pipe through flanges.

[0029] Furthermore, the ultrafiltration membrane system is connected to the micro-flocculation mixer through the second water inlet pipe, and then connected to the water inlet of the hollow fiber membrane module. The water outlet of the hollow fiber membrane module is connected to the clean water tank through the water outlet pipe, and the pipeline is controlled by the third electromagnetic valve. A backwashing device is provided in the ultrafiltration membrane system, and the backwashing cycle is set by the program to clean the membrane pollutants adsorbed in the hollow fiber membrane module.

[0030] Beneficial effects: The micro-flocculation-ultrafiltration reactor and the method of use of the present invention can flexibly respond to changes in high turbidity water during rainstorms. By controlling the solenoid valve, the entire device can form a continuous flow system. Compared with existing rural drinking water treatment equipment, the process flow is simpler, the operation and management are more convenient, and the membrane operation life is greatly improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a structural schematic diagram of the present invention.

[0032] In the figure: 1-first turbidity meter; 2-flange; 3-electromagnetic valve; 4-motor; 5-metering pump; 6-dosing pipe; 7-mixing unit; 8-ultrafiltration water inlet pipe; 9-clean water tank inlet valve; 10-hollow fiber membrane assembly; 11-ultrafiltration water outlet pipe; 12-backwash pipe; 13-clean water tank inlet valve; 14-drain valve; 15-drain pipe; 16-backwash pump; 17-backwash valve; 18-clean water tank. DETAILED DESCRIPTION

[0033] The present invention will be further described below in conjunction with the accompanying drawings.

[0034] like Figure 1 As shown, a micro-flocculation-ultrafiltration reactor of the present invention which can flexibly cope with the changes of high turbidity water during rainstorm period comprises a clear water tank, wherein the clear water tank is connected to an ultrafiltration water outlet pipe, a clear water tank water inlet valve is arranged on the ultrafiltration water outlet pipe, the ultrafiltration water outlet pipe is connected to a plurality of hollow fiber membrane modules, the bottom of the hollow fiber membrane module is connected to an ultrafiltration water inlet, a sewage pipe is also arranged at the bottom of the hollow fiber membrane module, a sewage pipe is arranged on the sewage pipe, a sewage valve is arranged on the sewage pipe, the ultrafiltration water inlet is connected to the ultrafiltration water inlet pipe, a mixing unit is arranged on the ultrafiltration water inlet pipe, a dosing device is arranged on one side of the mixing unit, a first turbidity meter and a first solenoid valve are arranged at the front end of the ultrafiltration water inlet pipe, a water level meter is arranged in the clear water tank, the water level meter is connected to the controller signal, and the controller is connected to the first solenoid valve signal and the dosing device signal.

[0035] In the present invention, the dosing device includes a medicine storage tank, a screw conveyor, a metering pump and a dosing pipe. A solenoid valve and a metering pump are provided under the medicine storage tank. The solenoid valve is connected to the screw conveyor, and the screw conveyor is connected to the dosing pipe. The dosing pipe delivers the medicine to be added into the ultrafiltration water inlet pipe. The second solenoid valve and the metering pump are connected to the controller signal.

[0036] In the present invention, the mixing unit body is composed of rotating blades or spiral bodies, and both ends of the mixing unit body are connected to the ultrafiltration water inlet pipe through flanges.

[0037] In the present invention, a backwash device is provided between the clean water tank and the hollow fiber membrane assembly, and the backwash device comprises a backwash pump backwash pipe, one end of the backwash pipe is connected to the bottom of the clean water tank, and the other end is connected to the top of the hollow fiber membrane assembly, and a backwash valve and a backwash pump are provided on the backwash pipe.

[0038] In the present invention, a second turbidity meter and a circulation inlet are provided between the mixing unit and the ultrafiltration water inlet, a third solenoid valve is provided at the front end of the ultrafiltration water inlet, the circulation inlet is connected to the circulation pipeline, the circulation outlet is located between the first solenoid valve and the dosing device, the circulation pipeline is connected to the circulation outlet, and the third solenoid valve is connected to the controller signal.

[0039] A method for using a microflocculation-ultrafiltration reactor that flexibly responds to changes in high turbidity water during a rainstorm period comprises the following steps: (1) Connect the above structures as required, set the water level threshold of the clean water tank and the turbidity threshold of the ultrafiltration inlet pipe; (2) When rainfall occurs, the controller reads the values ​​of the first turbidity meter and the water level meter. When the water level in the clean water tank exceeds the threshold, the controller controls the first solenoid valve to close. When the water level in the clean water tank is lower than the threshold, the controller reads the value X of the first turbidity meter. When the turbidity of the inlet water reaches 40 NTU, the second solenoid valve is started. The dosing amount of the dosing device is Q, Q=0.00035(X-40)+0.1, X is the turbidity, the unit is NTU, and the controller reads the value of the second turbidity meter in real time. When the value of the second turbidity meter is higher than 15.0 NTU, the third solenoid valve is closed and the circulating water pipe is opened. When the value of the second turbidity meter is lower than 15.0 NTU, the third solenoid valve is opened and the water enters the hollow fiber membrane module for further treatment, and finally obtains daily drinking water that meets the standards.

[0040] Taking streams, a typical water source for rural water supply, as an example, the water was treated by direct ultrafiltration and microflocculation-ultrafiltration processes respectively. The treatment results of the two processes under the same operating conditions were compared, and the four indicators of effluent turbidity, UV254, dissolved organic matter removal rate and membrane water production flux were investigated respectively to illustrate that the microflocculation process carried out in the device can synergistically improve the treatment effect of direct ultrafiltration on high-turbidity raw water during heavy rain periods.

[0041] 1. The turbidity treatment efficiency of the ultrafiltration effluent after pretreatment of the present invention is improved. Under the condition that the inlet turbidity is 40.15 NTU, the turbidity of the direct ultrafiltration effluent is 0.62 NTU, while the turbidity of the test effluent after pretreatment is reduced to 0.28 NTU; under the condition that the inlet turbidity is 136.5 NTU during the heavy rainfall period, the turbidity of the test effluent after pretreatment is reduced to 0.81 NTU, which is better than the turbidity of the direct ultrafiltration effluent of 1.17 NTU.

[0042] 2. Compared with direct ultrafiltration, the micro-flocculation pretreatment device of the present invention can increase the UV254 removal rate of ultrafiltration effluent from about 65% to more than 90% in both non-rainfall period and heavy rainfall period, which greatly improves the removal effect of organic matter.

[0043] 3. For water sources with high content of dissolved organic matter, the low mixing speed of the device of the present invention can make small particles and dissolved organic matter aggregate and condense to form larger aggregates, thereby effectively improving the removal efficiency of dissolved organic matter. The three-dimensional fluorescence image of the effluent after pretreatment is significantly lighter than that of the original water, and the fluorescent area is almost invisible. It can be judged that the device has a significant effect on the removal of dissolved organic matter.

[0044] 4. After pretreatment by the device of the present invention, the subsequent ultrafiltration membrane system flux is significantly improved. The initial flux of the ultrafiltration membrane in the non-rainfall period is increased from 150 L / m 2 •h to 250 L / m 2 •h, the initial flux of the ultrafiltration membrane during the heavy rainfall period increased from 120 L / m 2 •h to 200 L / m 2 •h. After filtering 3L of water, the membrane flux in the two cases increased from 20 L / m 2 •h to 45 L / m 2 •h.

[0045] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A microflocculation-ultrafiltration reactor that can flexibly cope with changes in high turbidity water during rainstorms, characterized in that: The invention comprises a clear water tank, wherein the clear water tank is connected to an ultrafiltration water outlet pipe, the ultrafiltration water outlet pipe is connected to a plurality of hollow fiber membrane modules, the bottom of the hollow fiber membrane module is connected to an ultrafiltration water inlet, the ultrafiltration water inlet is connected to an ultrafiltration water inlet pipe, a mixing unit is arranged on the ultrafiltration water inlet pipe, a dosing device is arranged on one side of the mixing unit, a first turbidity meter and a first solenoid valve are arranged at the front end of the ultrafiltration water inlet pipe, a water level meter is arranged in the clear water tank, the water level meter is connected to a controller signal, and the controller is connected to a first solenoid valve signal and a dosing device signal.

2. The microflocculation-ultrafiltration reactor for flexibly responding to changes in high turbidity water during rainstorms according to claim 1 is characterized in that: The dosing device includes a medicine storage tank, a screw conveyor, a metering pump and a dosing pipe. A solenoid valve and a metering pump are provided below the medicine storage tank. The solenoid valve is connected to the screw conveyor, and the screw conveyor is connected to the dosing pipe. The dosing pipe delivers the medicine to be added into the ultrafiltration water inlet pipe. The second solenoid valve and the metering pump are connected to the controller signal.

3. The microflocculation-ultrafiltration reactor for flexibly responding to changes in high turbidity water during rainstorms according to claim 1 is characterized in that: The mixing unit body is composed of rotating blades or spiral bodies, and both ends of the mixing unit body are connected to the ultrafiltration water inlet pipe through flanges.

4. The microflocculation-ultrafiltration reactor for flexibly responding to changes in high turbidity water during rainstorms according to claim 1 is characterized in that: A backwash device is provided between the clean water tank and the hollow fiber membrane assembly. The backwash device comprises a backwash pump and a backwash pipe. One end of the backwash pipe is connected to the bottom of the clean water tank, and the other end is connected to the top of the hollow fiber membrane assembly. A backwash valve and a backwash pump are provided on the backwash pipe.

5. The microflocculation-ultrafiltration reactor for flexibly responding to changes in high turbidity water during rainstorms according to claim 1 is characterized in that: A second turbidity meter and a circulation inlet are provided between the mixing unit and the ultrafiltration water inlet, a third solenoid valve is provided at the front end of the ultrafiltration water inlet, the circulation inlet is connected to the circulation pipeline, the circulation outlet is located between the first solenoid valve and the dosing device, the circulation pipeline is connected to the circulation outlet, and the third solenoid valve is connected to the controller signal.

6. A method for using a microflocculation-ultrafiltration reactor for flexibly responding to changes in high turbidity water during a rainstorm period as claimed in any one of claims 1 to 5, characterized in that: The following steps are involved: (1) Connect the above structures as required, set the water level threshold of the clean water tank and the turbidity threshold of the ultrafiltration inlet pipe; (2) When rainfall occurs, the controller reads the values ​​of the first turbidity meter and the water level meter. When the water level in the clean water tank exceeds the threshold, the controller controls the first solenoid valve to close. When the water level in the clean water tank is lower than the threshold, the controller reads the value X of the first turbidity meter. When the turbidity of the inlet water reaches 40 NTU, the second solenoid valve is started. The dosing amount of the dosing device is Q, Q=0.00035(X-40)+0.1, X is the turbidity, the unit is NTU, and the controller reads the value of the second turbidity meter in real time. When the value of the second turbidity meter is higher than 15.0 NTU, the third solenoid valve is closed and the circulating water pipe is opened. When the value of the second turbidity meter is lower than 15.0 NTU, the third solenoid valve is opened and the water enters the hollow fiber membrane module for further treatment, and finally obtains daily drinking water that meets the standards.

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