TW201100161A - Method of filtration and membrane filtration equipment - Google Patents

Abstract

This invention provides a filtering method that is characterized in that raw water is filtered to obtain filtered water by performing a membrane component with filter operation through a pressure as a driving force. The filter operation comprises three modes of a raw water side pressurizing filtration, a filtered water side pressure reduction filtration and a composite filtration combining the raw water side pressurizing filtration and the filtered water side pressure reduction filtration so as to measure at least one of the raw water side water quality, the membrane filtering flux and the membrane differential pressure, and any filtering among the three modes is switched to another filtering according to the measured value.

Description

201100161 VI. Description of the invention: [Technical field to which the invention pertains] The present invention relates to a pressure for treating tap water, industrial water, river water, lake water, ground water, water storage, sewage secondary treatment water, sewage, wastewater, etc. A method of filtering and a membrane filtration device using a membrane module for driving force. [Prior Art] Membrane filtration using a pressure-driven liquid has two types: a raw water side pressurized helium and a filtered water side decompression filter. The raw water side pressurization is applied to the raw water side of the membrane, and the filtered water side is normally opened to atmospheric pressure, thereby causing a pressure difference (membrane differential pressure) between the raw water side and the filtered water side of the membrane to be filtered. On the other hand, the filtration and water-side pressure filtration are generally performed by opening the raw water side of the membrane to atmospheric pressure and decompressing the filtered water side, thereby generating a membrane pressure difference and filtering. In the method as described above, if the raw water is filtered by the membrane, the suspended matter in the raw water or the substance having a pore size larger than the pore size of the membrane to be used is blocked by the membrane to form a concentration polarization or filter cake layer, and the pores are The clogging increases the filtration resistance (hereinafter referred to as "membrane contamination", and the substance that causes membrane fouling is referred to as "membrane contamination causative substance"), so that the membrane filtration flow rate (membrane filtration flux) is continuously fixed. During the process, the membrane differential pressure continues to rise. If the differential pressure of the membrane rises, chemical cleaning must be performed. In view of both cost and environmental load, the number of chemical cleanings is preferably as small as possible. In other words, it is preferable to suppress the increase in the membrane differential pressure while ensuring that the membrane filtration flux is fixed for a long period of time during continuous filtration and operation of the membrane. In the method of suppressing the increase in the differential pressure of the membrane, a method of treating a membrane by circulating the liquid supplied to the membrane flow path by the pressure of the circulation pump is disclosed in Japanese Laid-Open Patent Publication No. Hei No. 300168. The membrane was cleaned, and the liquid was passed through a filter membrane using a suction pump to obtain filtered water. [Problems to be Solved by the Invention] However, in the prior film processing method disclosed in Japanese Laid-Open Patent Publication No. Hei-300168, the power to obtain the filtrate does not actually depend on the pressure of the circulation ring pump. Depending on the suction force of the suction pump, there is a possibility that the filtration flux of the design cannot be ensured when the membrane differential pressure is increased due to membrane fouling. SUMMARY OF THE INVENTION An object of the present invention is to provide a filtration method and a membrane filtration apparatus which are capable of suppressing an increase in membrane differential pressure while maintaining a membrane filtration flux of a designed membrane and continuously performing a stable filtration operation for a long period of time. [Means for Solving the Problems] In order to achieve the above object, the present invention is: ◎ (1) A method for over-and-under consideration, which is characterized in that it filters a raw water by performing a filtering operation using a pressure as a driving force on a membrane module. Obtaining the filtered water; and the filtering operation includes three aspects of the raw water side pressure filtration, the filtered water side pressure filtration, the combined raw water side pressure filtration and the filtered water side pressure filtration, and the raw water side water quality is measured. At least one of the membrane filtration flux and the membrane differential pressure is switched from the other of the above three modes to another filtration based on the measured value. (2) The filtration method according to the above (1), wherein the measured value is a characteristic value X' indicating a concentration of the membrane contamination-causing substance calculated from the water quality of the original 140666.doc 201100161, wherein the characteristic value X is lower than the When the threshold value is set, the raw water side pressure filtration is performed, and when the characteristic value X is higher than the critical value, the pressure is switched from the raw water side to the composite overfishing. (3) The filtration method according to (2) above, wherein the characteristic value X is calculated from at least one of a raw water side turbidity A (degree) and a raw water side total organic carbon amount (mg/L). (4) The filtration method according to the above (3), wherein the turbidity on the raw water side is A (degree), and the total organic carbon amount on the raw water side is B (mg/L), the characteristic value X is X= Calculated by A+B. (5) The filtration method according to (1) above, wherein the measurement value is a membrane filtration flux, and the measurement value is lower than a predetermined value in a constant flow filtration operation using a design flow rate of the filtered water side pressure reduction filtration In the case of the membrane filtration flux, the filtration from the filtered water side is switched to the raw water side pressure filtration or the above composite filtration. (6) The filtering method according to (1) above, wherein the measured value corresponds to a suction lift force on the filtered water side of the membrane differential pressure, and in a constant flow overrun operation using a design flow rate of the filtered water side decompression transition, When the suction lift force on the above-mentioned water-repellent side is effective to delete H (available net positive sucti〇n head', the switch from the filtered water side to the above-mentioned raw water side pressure filtration or the above composite filter. (7) The filtration method according to any one of the above (1) to (6), wherein the above-mentioned over-washing operation and the backwashing operation are performed alternately in the above-mentioned backwashing operation, and the filtered water side of the water is supplied to the raw water side. Backwashing of the liquid supply, and gas cleaning of the membrane module described in 140666.doc 201100161. (8) The filtration method according to (7) above, wherein in the case of performing the backwashing operation, the pressure backwashing is performed from the filtered water side pressurization. ^ (9) The filtration method of (7) above, wherein the backwashing operation is performed

At the time, the decompression backwashing of the raw water side decompression is performed. V (10) The filtration method of the above (7), wherein in the case of performing the backwashing operation, the combined backwashing of the pressure from the filtered water side and the decompression backwashing of the raw water side pressure wash. 〇(1)) The filtration method of the above (7), wherein the pressure backwashing from the filtered water side pressure, the pressure backwashing on the raw water side pressure reduction, and the pressure backwashing combined with the pressure from the overfishing side can be selected. And any one of the backwashing of the decompression backwashing of the raw water side decompression, in the case of performing the backwashing operation, selecting any one of pressure backwashing, decompression backwashing, and compound backwashing By. (12) A membrane filtration device characterized in that it has a membrane module that uses pressure as a driving force, and includes: a first pressure regulating mechanism that adjusts a pressure of a raw water side of the membrane module; and a second pressure regulation a mechanism for adjusting the pressure of the filtered water side of the membrane module; a measuring mechanism for measuring the water quality of the raw water side of the membrane module; and a control mechanism for driving the control according to the measured value measured by the measuring means 1 at least one of a pressure regulating mechanism and the second pressure regulating mechanism; and the control mechanism performs pressure filtration on the raw water side, filtered water side pressure filtration, and combined filtration of the raw water side pressure filtration and the filtration water side pressure reduction filtration In one of the three aspects, switching from one type of filtering to another. (13) The membrane filtration device according to (12) above, wherein the second pressure regulating mechanism 140666.doc 201100161 is a pressure reducing pump, and the measuring means is at least one of a turbidity meter and a total organic carbon amount measuring device. (14) The membrane filtration device according to the above (12) or (13), wherein the control means drives and controls at least one of the first pressure regulating mechanism and the second pressure regulating mechanism to pressurize the filtered water side Backwashing, decompression backwashing of the raw water side decompression, and combined backwashing of the pressurized backwashing of the filtered water side and the depressurization backwashing of the raw water side decompression. [Effects of the Invention] According to the present invention, it is possible to suppress the increase in the differential pressure of the membrane while ensuring the filtration flux of the membrane to be designed, and to continuously perform a stable filtration operation for a long period of time. [Embodiment] An embodiment of a membrane filtration device of the present invention will be specifically described with reference to the drawings. As shown in Fig. 1, the membrane filtration device 5 of the present embodiment includes a membrane module 4 in which a solid-liquid separation membrane (hereinafter referred to as "membrane") is housed in a cartridge. The membrane filtration device 5 is a device for obtaining filtered water by using the membrane module 4 as a driving force by removing the suspended matter and the material having a size larger than the pore diameter of the membrane module 4 from the raw material. The film system of the present embodiment has an inner diameter of 〇. 7 , an outer diameter of i 2 mm (j), and an average pore diameter (M called a polyvinylidene-difluoroethylene (PVDF) hollow fiber-like micro ) (MF). The film has an effective membrane area of 7.4 m2 from the membrane module 4 having a surface area other than that of the medium-sized microfiber. Further, the membrane assembly j1 and the waist assembly 4 are housed in a length of 1 m and a diameter of 84 mm. Polyethylene (PVC) Naiyun Yun > Mine V) 砮 s inside and outside the pressure raw water side pressurized over-type components. 140666.doc 201100161 In addition, the raw material of the film is not particularly limited, and examples thereof include polyethylene, polypropylene, polybutylene, and the like; and tetragas, full gas, and ethylene (tetra) copolymer (PFA), and four. Fluoroethylene hexafluoropropylene copolymer (IV). , tetrafluoroethylene·hexafluoropropylene-perfluoro-formylethylacetate copolymer_), tetraethylene ethylene/ethylene copolymer (ΕΊΤΕ), polychlorotrifluoroethylene (pCTFE), chlorotrifluoroethylene-ethylene Superplastic engineering plastics such as copolymers (ECTFE), polyvinylidene bromide (pVDF), fluorine-based resins, polyethers, polyethersulfones, polyetherketones, polyetheretherketones, polyphenylene sulfides, etc.; Cellulose such as ethyl cellulose; polyacrylonitrile; polyethylene glycol alone component and mixtures thereof. Further, as the shape of the film, any shape such as a hollow fiber shape, a flat film shape, a pleated shape, a spiral shape, or a tubular shape can be used. The hollow fiber shape is particularly good because of the high backwashing effect. As the membrane module of the present embodiment, the following may be preferably used: the ends of either or both of the bundles of the plurality of t hollow fiber separation membranes are fixed to each other, and one or both of them are fixed. The hollow fiber membrane end of the end is open. The cross-sectional shape of the end portion to be fixed next may be, for example, a square shape, a hexagonal shape, an expanded circular shape or the like. The film of the present embodiment and the film module 4 having the film are used to explain an example of the present invention. Further, the membrane filtration device 50 includes a raw water tank 2, a water tank 6 for storing the filtered water of the membrane module 4, a raw water inlet 4a of the membrane module 4, and a raw water introduction line of the raw water tank 2, and The waste water from the waste water side outlet 4c of the membrane module* is returned to the raw water loop pipe 53 of the raw water tank 2. The raw water introduction line 5 1 is provided with a raw water pressure 140666.doc 201100161 accumulated in the raw water tank 2 The pressure regulating filter pump 3 of the membrane module 4 is provided with valves 14 and 24 on the upstream side and the downstream side of the pressure regulating filter pump 3, respectively. The valve 24 and the membrane module 4 on the downstream side of the pressure regulating filter pump 3 are further disposed. An air introduction pipe 5u is connected between the air introduction pipe 51a and a compressor ίο that supplies air for cleaning the membrane of the membrane module 4, and a valve 22 is provided in the air introduction pipe 51a. The road 52 is provided with a valve 23 for opening the pipeline when discharging the waste water. The pressure regulating filter pump 3 is equivalent to the third pressure regulating mechanism for adjusting the pressure of the raw water side. Further, the raw water introduction line 51 is connected to the raw water circulation. The first backwashing pipe with the pipe 53 connected and the backwashing water flowing The first backwashing water line 71 and the second backwashing water line 72 are used to introduce waste water from the waste water side outlet 4c of the membrane module 4 by the driving of the pressure regulating filter pump 3. The pipeline for supplying liquid to the waste water discharge line 52 is provided with valves 26 and 27 on the backwash water line 71 and the second backwash water line 72. The raw water tank is provided with a raw water inlet port. Further, a raw water circulation pipe 53 connected to the waste water side outlet 4c of the membrane module 4 is connected. The raw water circulation pipe 53 is provided with a valve 15. Further, the raw water tank 2 is provided with a water quality measurement for measuring the water quality of the raw water side. The water quality measuring device is at least the square of the carbon measuring device. The water quality measuring device (1) is a measuring mechanism for the water quality on the side of the 敎^ side. Further, the membrane filtering device 50 is provided with the filtered water side of the connecting membrane module 4. The outlet is flushed with the water filtration pipe 55 of the water filter tank 6. The water filtration pipe 55 is divided into two directions in the middle, and the square side is the first pipe 57 which sends the water to the water tank 6 without being decompressed. On the other side, the filtered water is sent from the membrane module 4 to the second conduit 58 of the water filter tank 6 by depressurization. The inlet of 57 is provided with a valve 140666.doc -10·201100161 16, and a valve 17 is provided at the inlet of the second line 5S. Further, the membrane filtration device 50 includes a raw water inlet pressure measuring device disposed on the raw water introduction line 51. 12a, a filtered water side pressure measuring device 12b disposed on the water filtering line 55, a raw water outlet pressure measuring device 12c disposed on the raw water circulation pipe 53, and a membrane excess flux measuring device 13. Raw water inlet pressure measuring device 12a, raw water The outlet pressure measuring device 12c and the filtered water side pressure measuring device 12b are devices for measuring the pressure at each position. The membrane filtration flux measuring device 13 is a device for measuring the membrane filtration flux of the transition water flowing through the first conduit 57. In addition, when the pressure measured by the raw water inlet pressure measuring device 12a is Pi, the pressure measured by the raw water outlet pressure measuring device 12c is Pp, and the pressure measured by the transitional water side pressure measuring device 12b is p〇, Membrane differential pressure? (1 is calculated by the following formula:

Pd=(Pi+p〇)/2-pp · . · · (Formula). The second line 58 is divided into two directions in the middle, one side is the over-sleeve side line 59, and the other side is the backwash side line 61. The filter side line 59 is provided with a pressure reducing filter pump 5, and valves 18 and 19 are provided on the upstream side and the downstream side, respectively, so as to sandwich the pressure reducing filter pump 5. Further, a backwashing pump 7 is provided on the backwashing side line 6A, and a valve 21 is provided on the downstream side and the upstream side of the pressurized backwashing pump 7 based on the flow direction of the backwashing water. And valve 2〇. The decompression filter pump 5 corresponds to a second pressure regulating mechanism that adjusts the pressure on the filtered water side. In the present embodiment, the pressure-regulating filter pump 3 is disposed on the raw water side of the membrane module 4, and the pressure-reducing filter 5 is connected in series on the transition water side. Since the pressure-regulating filter pump 3 and the pressure-reducing filter pump 5 can be disposed independently of each other, it is preferable to be arranged in a manner other than 140666.doc 201100161. Further, the membrane filtration and apparatus 50 includes a chemical supply line 63 for accumulating the oxidant unit 8 as the oxidizing agent tank 8 and the oxidizing agent unit 4 for oxidizing the oxidizing agent. Kawasaki " On the chemical music supply line 63, an oxidizing agent is sent to the "9, and then" is placed on the side of the oxidizing agent. The chemical supply line 63 is connected to the second line 58 of the second line 58. The position of the upper phase and the filtration and water pipelines, and the membrane over-distribution M) have the control (4) operation and backwashing operation. (4) Unit (10) 'The above transition operation uses the membrane module 4 to transition the raw water i. The above-mentioned backwashing operation system Gas cleaning of the membrane module 4 by the backwashing disk of the transition water through the membrane module 4 is simultaneously performed. The control unit (4) is connected in such a manner as to control signals for each of the pumps 3, 5, 7, 9 and the compressor. The control unit 40 is connected to each of the valves 14, 15, 16, 17, i8 m, 22, 24, 25, 26, 27 to transmit and receive control signals. Further, the control unit 40 is connected so as to receive the measured value data related to the water quality of the raw water tank measured by the water quality measuring device u, and further receives the raw water inlet pressure measuring device 12a, the filtered water side pressure measuring device 12b, and The raw water outlet pressure measuring device 12c is connected to the measured value data of the membrane differential pressure, and is connected by receiving the measured value data related to the membrane filtration flux measured by the helium filtration flux measuring device 丨3. . The control unit 40 includes a central processing unit having a CPU (Central Processor Unit), a RAM (Random Access Memory), and R〇M (Reacl Only 140666.doc -12- 201100161).

Memory, read-only memory, etc. are configured as hardware, and have a control unit, a calculation unit, and a memory unit as functional components. Furthermore, the control unit 4A includes a threshold value that is set in advance to obtain a predetermined set value, for example, a characteristic value 评价 indicating a concentration of a membrane contamination causative substance calculated from the raw water side water quality, and is an evaluation membrane rushing amount. The input device for reducing information such as the reference membrane filtration flux or the effective NPSH (available net positive SUcti〇n head), and an output device such as a monitor for outputting various information.

The control unit 40 transmits and outputs a control signal to each of the pumps 3, 5, 7, and 9 and the compressor 1 to drive and stop the drive of each of the pumps 3, 5, 7, and 9 and the compressor. Moreover, the control unit 40 transmits a control signal 16 to each of the valves 14, 15, 16', 17, 18, 19, 20, 21, 22, and 'by the valves 14, 15, 24, 25, 26, 27, 17, 18, 19, 20, 21,

22, 24, 25, 26, 27 opening and closing control. Further, the control unit 4 detects the difference in the water quality of the raw water measured by the water quality measuring device 11 by the raw water inlet pressure measuring device 12a, the filtered water side pressure measuring device nb, and the raw water outlet pressure measuring device 12e. The pressure-related measured value is monitored by the enthalpy value associated with the membrane filtration flux measured by the membrane filtration flux meter 13, and the suction lift of the vacuum filtration pump 5 is monitored. The control unit 4 of the membrane filtration apparatus 5 of the present embodiment performs a transient operation of the membrane module 4 with a pressure as a driving force. *, the control unit performs a backwashing operation'. The backwashing operation simultaneously performs backwashing of the mixed liquid of the hydrophobic water and the oxidant from the transition water side of the membrane module 4 to the raw water side and the gas of the membrane of the membrane module 4 ;first. The control unit 4Q effectively suppresses clogging of the membrane by alternately over-reacting the operation with the backwashing operation. [Filtering Operation] First, the filtering operation performed by the control unit 40 will be described. Among the filtering operations performed by the control unit 40, there are three aspects of the raw water side pressurization filtration, the filtered water side decompression filtration, and the combination of the raw water side pressure filtration and the filtration water side decompression filtration. (The raw water side pressure filtration) As shown in Fig. 2, when the raw water side pressure filtration is performed, the control unit 40 opens the first pipes of the valves 14, 24 and the water filtration line 55 provided in the raw water introduction line 51. The valve 16 is provided on the 57, and the valve 22 for supplying the air for gas cleaning, the valve μ for supplying the oxidant, and the second b of the water filtering line 55 are closed. In order to form a fluid flow path for pressure filtration on the raw water side, the control unit 40 drives the pressure regulating filter pump 3. As shown in Fig. 2, the raw water 1 is pumped through the raw water tank 2 by driving the pressure regulating filter pump 3. To the membrane module 4. The filtered water that has passed through the membrane module 4 is sent to the aqueduct 6 through the i-th line 57 of the water filtration line 55. Further, if the valve 15 provided on the raw water circulation pipe 53 is closed for filtration, it becomes an end point. (4) In the mode, if the opening degree of the regulating valve 15 is opened, it becomes a circulation filtering method. (Filtering water side decompression transition) As shown in Fig. 3, when the filtered water side decompression filtering is performed, the control unit 40 opens the raw water. The valve 14 and μ provided on the introduction line 51 and the second line 58 of the water filtration line 55 are provided. 17 and the transition side pipe of the second pipe 58 140666.doc • 14· 201100161 The valve 18 is provided on the road 59. Further, the valve 22 for supplying air for gas cleaning and the valve for supplying the oxidant are closed. 25 and the valve 16 provided in the first line 57 of the water filtration line 55. As a result, a fluid flow path for filtering the water side of the filtered water side is formed. Further, the fluid flow path for filtering the water side for filtration under pressure is formed. The same as the fluid flow path of the composite filtration. Then, the control unit 40 drives and controls the pressure regulating filter pump 3 and the pressure reducing filter pump 5. By the driving control of the control unit 40, the raw water i is filtered by the pressure regulating water through the raw water tank 2 The pump 3 is sent to the membrane module 4, and is depressurized by a vacuum filter pump 5 connected to the membrane water filter side of the membrane module 4 to obtain filtered water. In the filtration water side pressure reduction filtration of the present embodiment The control unit 4 drives and controls the pressure regulating transition system 3 in such a manner as to apply a minimum pressure that can supply the raw water 1 to the membrane module 4. Therefore, the driving force for obtaining the water is actually only reduced by Pressure filter pump 5 is provided. Furthermore, it is also possible to drive the pressure regulation overfishing. 3. The piping that bypasses the pressure regulating filter pump 3 is set and switched by the valve. (Composite over) As shown in Fig. 3, in the case of composite filtration, the control unit 4 is decompressed and filtered. The fluid flow path for filtering is the same as the fluid flow path. Then, the control unit 40 drives the pressure regulating pump 3 and the pressure reducing filter pump 5 which have both the raw water supply effect. As a result, the raw water 1 is filtered by the pressure regulating pump 3 The membrane module 4 is pressure-fed through the raw water tank 2, and the filtered water side is depressurized by the vacuum filter pump 5, and both pressurized and depressurized are simultaneously performed, and the filtered water is obtained by the above method. The filtered water is stored in a furnace and a water tank 6 which also serves as a backwash tank. [Backwashing operation] 140666.doc -15- 201100161 Further, in the case where the transition operation is continuously performed and the film differential pressure is increased, it is preferable to perform physical cleaning such as backwashing and gas cleaning. The term "backwashing" refers to a method of removing the membrane fouling substance adhering to the pores of the membrane and the raw water side by allowing the filtered water to pass from the filtered water side of the membrane of the membrane module 4 to the raw water side. In addition, the gas cleaning means a method of introducing a gas such as air into the raw water side of the film in the form of bubbles, thereby shaking the film to remove the film contamination causing substance deposited on the raw water side of the film. It is considered that when the pressure actually applied to the raw water side is low and the compression of the substance causing the membrane contamination is suppressed, the membrane contamination causing substance is easily removed by physical cleaning. The membrane filtration device 50 of the present embodiment alternately performs the above-described filtration operation and backwashing operation. Here, the backwashing operation by the control unit 4A of the membrane filtration device 5A will be described. In the backwashing operation of the present embodiment, there are three aspects of the backwashing backwashing, the raw water side pressure backwashing, and the combined filtering water side pressure backwashing and the raw water side pressure reducing backwashing. (Filtered water side pressure backwashing) As shown in Fig. 4, the backwashing step and the draining step were carried out in the pressurization backwashing on the filtered water side. First, the control unit 40 opens the valve 21 provided on the second line 58 of the water filtration line 55 and the valves 2, 21 provided on the backwash side line 61, thereby opening the valve 23 provided in the waste water discharge line 52. On the other hand, the valve dam 8 provided on the filter side line 59 and the valve 24 provided on the raw water introduction line 5 关闭 are closed. As a result, a fluid flow path for forming a backwash is formed. In addition, the formation of the fluid flow path for backwashing is to supply the oxidizing agent to the membrane module 4 to open the valve 25 provided in the chemical supply line 63, and further to supply the air for cleaning the membrane to the membrane module. 4, the valve 140666.doc is opened to open the air introduction pipe 5 la. 16 - 201100161 22 Then, the control unit 4 drives the pressurized backwashing pump 7, and the filtered water accumulated in the filter tank 6 which also serves as the backwash tank Pressed to the membrane module 4. Further, the oxidizing agent liquid feeding pump 9 is driven by the sputum 40, and the oxidizing agent is supplied to the filtered water for backwashing through the chemical supply line 63 to generate a mixed liquid, and the mixed liquid is sent from the filtered water side of the membrane module 4 to the raw water side. And backwashing. Further, the control unit 40 drives the compressor 1A to supply compressed air to the raw water 1 side of the membrane module 4 via the air introduction pipe 51a, and performs gas cleaning of the membrane. After the backwashing step described above, the control unit 40 performs a draining step. As shown in Fig. 6, the 'discharging step' is a step of discharging the object to be removed from the film in the backwashing step. In the draining step, the control unit 4 opens the valves 14 and 24 on the raw water introduction line 51 and the valve 23 on the waste water discharge line 52, and closes the other valves 16, Π, 22, 25, etc., to form a drain. Fluid flow path. Then, the control unit 40 drives the pressure regulating filter pump 3 to supply the raw water 1 to the membrane module 4. Here, the material to be removed which has accumulated on the raw water 1 side of the membrane module 4 is discharged to the waste water discharge line 52 through the waste water side outlet 4c of the membrane module 4 together with the raw water 1. (Original water side pressure backwashing) As shown in Fig. 5, in the raw water side pressure backwashing, a backwashing step and a draining step are performed. In the backwashing step, the control unit 40 opens the valve π provided on the second line 58 of the water filtration line 55 and the valves 2〇, 21 provided on the backwash side line 61, thereby opening the waste water discharge line 52. The valve 23 opens the first backwash water line 71 connected to the pressure regulating filter pump 3 and the valves 26 and 27 provided in the second backwash water line 72. On the other hand, the valves 140666.doc -17· 201100161 18 provided on the filter side line 59 and the valves 14 and 24 provided on the raw water introduction line 51 are closed. As a result, a fluid flow path for backwashing is formed. Further, a valve 2 2 for supplying air for cleaning the gas and a valve 25 for supplying the oxidant are opened. Then, the control unit 40 drives and controls the pressure reduction of the raw water side of the membrane module 4 by the pressure regulating filter pump 3, and further drives and controls the pressurized backwashing pump 7. By the drive control of the control unit 40, the filtered water accumulated in the filter tank 6 serving as the backwash tank is sent to the membrane module 4, and is depressurized by the pressure regulating filter pump 3 connected to the raw water side of the membrane module 4. This performs backwashing. In the raw water side depressurization backwashing of the present embodiment, the control unit 4 drives and controls the pressurized backwashing pump 7 so as to apply a minimum pressure to supply the filtered water to the membrane module 4, thereby performing the reverse The driving force for washing is actually provided only by the pressure regulating filter pump 3. Further, the piping that bypasses the pressurized backwashing 17 may be provided without driving the pressurized backwashing pump 7, and the valve may be switched. After the backwashing step, the control unit 4 performs the same draining step as that of the filtered water side pressure backwashing (see Fig. 6). (Composite backwashing) As shown in Fig. 5, in the composite backwashing, a backwashing step and a draining step are performed. In the backwashing step, the '35 system unit 4' forms a backwashing fluid flow path similarly to the original and water side pressure backwashing, and further opens the valve 22 for supplying the gas for gas cleaning and the oxidant for supplying the oxidant. Read 25. Then, the control unit 40 drives and controls the pressure reduction of the raw water side of the membrane module 4 by the pressure regulating filter pump 3, and further drives and controls the pressurized backwashing pump 7. By the drive of the control unit 40, the filtered water accumulated in the filter tank 6 serving as the backwash tank is pumped to the membrane module 4 by the pressurized backwash pump 7, and is utilized by 140666.doc -18-201100161. The dust filter pump 3 decompresses the raw water side, thereby performing both pressurization and depressurization, and backwashing by the above method. After the backwashing step, the control unit 40 performs the same draining step as that of the filtered water side pressure backwashing (see Fig. 6). [Switching control] The control unit 7L 40 measures the raw water side water quality measured by the water quality measuring device i, the membrane differential pressure measured by the membrane pressure measuring device 12, and the membrane filtered by the membrane filtration flux measuring device 13; The quantity is all monitored and the control unit 4() performs control for switching from any of the above three types of filtering to another filtering according to at least one of the measured values. The switching control by the control unit 4A will be described. As the switching control, for example, the control unit 4 can obtain the raw water side water quality as a measured value, and calculate the characteristic value X indicating the concentration of the membrane contamination causing substance from the obtained measured value, and the characteristic value χ is lower than a predetermined threshold value. When the barrier is opened, the raw water side pressure filtration is performed, and when the characteristic value X is higher than the critical value, the pressure filtration from the raw water side is switched to the composite filtration. The characteristic value X is calculated from the raw water side water quality. As a project of raw water side water quality, turbidity (degree), T0C (total organic carbon amount) (mg/L), CODMn (chemical oxygen demand test_high potassium acid method) (mg/L), c 〇DCr (chemical oxygen demand detection - potassium dichromate method) (mg / L), b 〇 D (biochemical oxygen demand) (mg / L) ' or the concentration of the following metals, Fe (mg / L), Mn (mg/L),

Al (mg/L), Si (mg/L), Ca (mg/L), and Mg (mg/L), the water quality measurement equipment can be omitted, and each water quality measurement value is used as a substance indicating membrane contamination. The characteristic value X. In the water quality measuring device of the present embodiment, at least one of the turbidity of 40666.doc •19-201100161 (degrees) and TOC (mg/L) is obtained, and the characteristic value X is calculated from each measured value. For example, the characteristic value X can be calculated only from turbidity (degrees) or only T〇c (mg/L), and can also be calculated from turbidity (degrees) and TOC (mg/L). When the characteristic value X is calculated from turbidity (degrees) and TOC (mg/L), the turbidity can be set to A (degrees) and the TOC can be set to B (mg/L) to χ=Α+Β Calculated by the value. Furthermore, TOC (mg/L) is the total amount of organic carbon. Further, when turbidity is used as the characteristic value X, it is preferable to set the critical value between the turbidity of 0.01 to 1000 degrees with respect to the critical value, and more preferably between 1 and 100 degrees. When T〇c is used as the characteristic value ,, it is preferable to set a critical value between 001 mg/L and 1 〇〇〇mg/L for the threshold value, and more preferably Mi mg/L. Set between ~1〇〇mg/L. When turbidity and TOC (A+B) are used as the characteristic value X, it is preferable that the critical value 'is a value of A+B between 〇.〇1 to 100〇, and a better value. It is set between 1 and 1〇〇 of A+B. Further, as another aspect of the switching control, for example, the control unit 4 may obtain the membrane filtration 'flux as a measured value' in the constant flow filtration operation using the designed flow rate of the filtered water side decompression filtration, and the obtained measurement is performed. When the value is lower than the preset membrane filtration flux, the filtration from the filtered water side is switched to the raw water side pressure filtration or the composite transition. Further, as another aspect of the switching control, for example, the control unit bucket may acquire the suction lift force on the filtered water side corresponding to the membrane pressure difference as a measured value in the constant flow rate filtering operation using the filtered flow side decompression filtration design flow rate. When the suction lift on the filtered water side reaches the effective NPSH, the filtered filter from the filtered water side is switched to the raw water side pressure filtration or the composite tear. 140666.doc -20. 201100161 Regarding the timing of switching and the aspect of switching control, in addition to the above various aspects. Next, the effect and effect of the switching control obtained by the control unit 40 will be described.

The raw water-based tap water, industrial water, river water, lake water, ground water, water storage, sewage secondary treatment water, wastewater, or sewage are preferable as the water to be treated of the present embodiment. If the membrane is used to make a transition to the raw water raft, the membrane fouling will occur, that is, the membrane layer and the pores will be formed due to the membrane contamination in the raw water 1, resulting in (4) increased resistance, so continuous flow operation is performed. During the process, the membrane differential pressure continues to rise. The present inventors have found that the raw water having a higher membrane fouling cause, a higher turbidity and a toc (total organic carbon amount), is subjected to a quantitative filtration operation at the same membrane filtration flux with a membrane differential pressure of less than atmospheric pressure. In the case of 'the original water side pressure filtration and the filtered water side pressure reduction filtration, the membrane differential pressure rises faster. In addition, the raw water 1 generally changes in water quality, and the amount of substances in the membrane contamination also changes. The present inventors have found that if the membrane in the raw water 1 is contaminated by sputum, the membrane contamination is rapidly increased. In this case, in particular, the filtered water side vacuum filtration can suppress the membrane differential pressure as compared with the raw water side pressure filtration. rise. It is considered that the difference between the raw water side pressure filtration and the filtration water side pressure reduction filtration as described above is caused by the difference in pressure actually applied to the raw water side of the membrane in which the membrane contamination cause substance exists. That is, in the raw water side pressure filtration, the pressure actually applied to the raw water side is the sum of the atmospheric pressure and the membrane pressure. On the other hand, in the filtered water side pressure filtration, the pressure actually applied to the raw water side is the atmosphere 140666. Doc -21 - 201100161 Pressure, the pressure applied to the raw water side is higher than the membrane pressure during the raw water side pressure filtration. When the raw water side pressure filtration or the filtration water side pressure filtration is operated with an equal membrane filtration flux, the initial membrane pressure difference is equal to 'the membrane contamination causative substance in the raw water 1 It is applied to the force in the direction perpendicular to the film. However, the actual pressure on the surface of the membrane on which the substance contaminated with the membrane is deposited is higher than the atmospheric pressure on the raw water side as compared with the filtration on the filtered water side. Therefore, it is considered that the filter cake layer formed on the surface of the membrane becomes denser in the raw water side pressure filtration in which the particles of the membrane fouling substance are more compressed and undergoes a shape change. It is considered that if backwashing and gas cleaning are simultaneously performed in this state, the effect of backwashing in the filtration of the filter cake layer becomes dense in the raw water side pressure filtration. Therefore, if the filtration operation for a long time is continuously performed, the pressure increase is faster as compared with the filtration of the raw water side by the same membrane filtration flux. The amount of the membrane-causing substance contained in the raw water is small, and the difference is as small as negligible, but if the amount of the substance causing the membrane contamination exceeds a certain fixed value, the difference becomes conspicuous. Therefore, it is considered that the filtration water side pressure reduction filtration is more advantageous than the raw water side pressure filtration, only considering the effect of backwashing or the like. However, in the case of the filtered water side decompression, the resulting membrane differential pressure is at most atmospheric pressure. Therefore, under the condition that the membrane differential pressure is equal to or higher than atmospheric pressure, the filtration water side decompression filtration cannot be used alone, and the designed membrane cannot be ensured. Filter the flux. That is, in the case of raw water with less membrane contamination causing substances, it is generally operated with a high membrane filtration flux, and the membrane differential pressure during stable operation is a high value of 140666.doc •22·201100161, so it cannot be used alone. After the dusting side of the water side, the dust is removed. Therefore, raw water side pressure filtration or composite filtration must be performed. Here, in the case where the amount of the membrane-causing substance in the raw water is large, in order to reduce the pressure actually applied to the raw water side of the membrane, it is better to select the composite over-wage as the driving force for obtaining the filtered water, and increase as much as possible. It is greater than the effect of reducing the heart on the side of the water's side and supplements the insufficient portion of the membrane through the raw water side. On the other hand, when the amount of the substance causing the membrane contamination in the raw water is small, (4) the efficiency of the amount is only advantageous by the use of the raw water side plus the waste filtration, and the use frequency of the decompressed fruit on the filtered water side is advantageous. And time suppression is minimal, which can make the life of the pump longer. That is, according to the membrane filtration device 50 and the filtration method performed by the membrane filtration device 5, the filtration pattern is switched in accordance with the water quality fluctuation of the raw water raft, the membrane filtration flux, and the membrane pressure to be optimally filtered. Since the operation is performed, even when the original water and water are changed, the membrane differential pressure can be suppressed from increasing at the membrane filtration flux, the number of chemical cleanings can be reduced, and the energy consumption can be minimized, and the life of the package can be extended. As a result, it is possible to suppress the increase in the differential pressure of the membrane in the state of the filter filtration and the flux designed by the dish, and to continuously perform the stable filtration operation for a long period of time. Further, in the membrane filtration device 50 and the filtration method performed by the membrane filtration device 5, any backwashing of the filtered water side pressure backwashing, the raw water side pressure reducing back washing, and the composite back washing is selected and performed. This allows for effective backwashing. For example, the original water side depressurization backwash is compared with the filtered water side pressure backwashing, and the actual pressure of the membrane surface deposited by the membrane fouling substance is less than atmospheric pressure. Therefore, it is generally believed that the compression of the substance causing the film contamination on the surface of the film is 140666.doc •23-201100161 to ease, and the backwashing effect is high. On the other hand, it is generally considered that it is the same as the filtration method. There is also a case where the backwashing of the design cannot be ensured by only the raw water side depressurization and backwashing. In this case, it is set as a composite backwash as a drive for obtaining backwashing water. The force, as much as possible, increases the effect of the raw water side decompression backwashing and supplements the insufficient portion by filtering the water side pressure backwashing, thereby performing better backwashing. Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments. For example, the first and second pressure regulating mechanisms for performing the raw water side pressure filtration 'filtered water side pressure reduction filtration, the composite filtration, the filtered water side pressure back washing, the raw water side pressure reducing back washing, and the composite back washing, Examples of the pressurizing means include a pressurizing pump, a pressure regulating pump, a high-pressure gas, and a head difference. Examples of the pressure reducing mechanism include a suction pump, a vacuum pump, and the like. [Examples] [Example 1] A river surface water having an average turbidity of 1 degree was used as raw water. The filtering operation and the backwashing operation are performed using the apparatus corresponding to the above membrane filtration device 50. This filtration operation is started by pressure filtration on the raw water side. From the water quality tester! The signal of i is sent to the control unit 40' to automatically switch to composite filtering by the control unit 40 from the time when the measured value reaches 5 degrees. The raw water side pressure filtration system is set to use a pressure regulating filter pump 3 at a fixed flow rate (membrane filtration flux is 2·5 m3/m2/曰', and a flow rate of 2.5 m3 of filtered water per 1 m2 of membrane area is obtained) The membrane module 4 supplies a constant flow rate of raw water 1 by means of an end point filtration method. The composite filtration system is set to use a pressure-regulating filter pump 3 at a fixed flow rate (membrane filtration 140666.doc •24· 201100161 flux is 2.5 m3/m2/day, and 2 5 claws 3 filtered water per m 2 membrane area per day The flow rate of the membrane module 4 is supplied to the membrane module 4, and the constant-flow filtration by the pressure-reducing filter pump 5 is performed by the end point filtration method. The speed of the vacuum filtration pump 5 in the composite filtration is the maximum speed of the pump, i.e., 5 Hz. In the present embodiment, the raw water side pressure filtration or the combined filtration and cleaning operation are alternately repeated, and as a working condition, the filtration operation is performed for 29 minutes, and the backwashing and gas cleaning are performed as the backwashing operation for 1 minute, and the discharge is performed 3 times. Repeat in seconds. The backwashing operation was carried out for 3.0 days, and the oxidizing agent feed pump 9 was supplied to the sodium hypochlorite in the oxidizing agent tank 8, so that the residual gas concentration of the backwash water was 3 mg/liter. The gas system for gas cleaning uses air compressed by the compressor 10, and the air flow rate is set to i 5 Nm3/hr. Under the above operating conditions, continuous operation was started from the raw water side pressure filtration method. As a result, after about 1,000 hours, the turbidity exceeded 5 degrees and reached 丨7 degrees (refer to Fig. 8), so that it was automatically switched to composite filtration. The membrane differential pressure increased to a maximum of 163 kpa, and after 3,000 hours, it became 145 kPa (see Figure 7). Within 3000 hours, it is possible to continuously operate while maintaining a predetermined membrane filtration flux of 2.5 m3/m2/day (refer to Fig. 9). [Comparative Example 1] A river surface water having an average turbidity of 丨 was used as raw water. The apparatus having the same configuration as that of the first embodiment except for the control unit 40 was used to perform the smashing operation and the backwashing operation, and the filtration operation was carried out simultaneously with the first embodiment by the raw water side pressurization. It is set to use the pressure regulating filter pump 3 at a fixed flow rate (membrane filtration flux is 2.5 m3/m2/曰, and the membrane area per 1 m2 per day can be obtained. 140666.doc -25- 201100161 The constant flow rate of the raw water 1 supplied to the membrane module 4 is carried out by the end point filtration method. ^ As a comparative example! The operating conditions were repeated by a filtration operation for 29 minutes, a backwash as a backwashing operation, and a gas purge for 0 minutes and a discharge for 30 seconds. The backwashing operation is performed at 3. 〇 mW/day, and the oxidizing agent feed pump 9 is used to supply the sodium hypochlorite in the oxidizing agent tank 8 so that the residual gas concentration of the backwash water reaches 3 mg/liter. The gas system for gas cleaning uses air compressed by the compressor 10 to set the air flow rate to 1.5 Nm3/hr. After continuous operation under the above-mentioned operating conditions, the film differential pressure became 200 kPa which required chemical cleaning after about 1050 hours, so the apparatus was stopped (refer to Fig. 2) [Comparative Example 2] The river surface water having an average turbidity of 1 degree was used. As the raw water, a filtration operation and a backwashing operation were carried out using a device having the same configuration as that of Comparative Example 1, and the transient operation was carried out simultaneously with the filtration of the filtered water side in the same manner as in Example 1. This was set to use the pressure-regulating filter pump 3 Fixed flow rate (membrane filtration flux is 2.5 m3/m2/day' per 1 day! m2 membrane area can obtain 2.5 m3 of filtered water flow). Membrane module 4 is supplied with raw water 1 for constant flow filtration. The operation conditions of Comparative Example 2 were repeated by a filtration operation for 29 minutes, a backwashing as a backwashing operation, a gas cleaning for 1 minute, and a discharge for 30 seconds. The backwashing operation was performed at 3.0 m3/m2/day. In the meantime, the oxidant liquid supply pump 9 is used to supply the sodium hypogasate in the oxidant tank 8, so that the residual gas concentration of the backwash water reaches 3 mg/liter. The gas system for gas cleaning is compressed by the compressor 10. air The gas and air flow rate are set to 1.5 Nm3/hr. Under the above operating conditions, 140666.doc -26- 201100161, the operation is continuous, and after 1000 hours, it is lower than the designed membrane filtration, 2.5 m3/m2/曰 of Tongli, the lowest is 1.5 m3/m2/曰 (refer to Fig. 9) [Example 2] A river surface water having an average turbidity of 〇.丨 was used as the raw water. The filtration operation and backwashing were carried out using a device having the same configuration as that of Example 1. The operation is started by filtering the water side pressure filtration, and automatically switches to the combined raw water side pressure filtration and filtration water side from the time when the measured value of the membrane differential pressure measuring device 12 reaches 8 kPa. The filtration method of the vacuum filtration is combined with the filtration method of the raw water side enthalpy pressure filtration and the filtration water side pressure filtration filtration method, and the rotation speed of the decompression pump 5 is continuously filtered and the membrane pressure difference is 8 kPa. The value of the composite filter system is set to use a pressure-regulating filter pump 3 at a fixed flow rate (membrane filtration flux is 5.0 m3/m2/day, and a flow rate of 5.0 m3 of filtered water per 1 m2 of membrane area per day) The membrane module 4 supplies the raw water 1 while using the vacuum pump 5 The constant flow filtration under reduced pressure was carried out by the end point filtration method. As the operating conditions of Example 2, the filtration operation was carried out for 29 minutes, and the backwashing and gas washing were performed as the backwash σ σ while the gas was washed for 1 minute, and discharged 3 〇. The backwashing operation is carried out in seconds. The backwashing operation is carried out at 3·8 m3/m2/day, and the oxidizing agent feed pump 9 is used to supply the sodium hypochlorite in the oxidizing agent tank 8, so that the backwashing residue has a chlorine concentration of 3 mg/ The gas system for gas cleaning uses air compressed by the compressor 10, and the air flow rate is set to 丨5 Nm3/hr. Under the above operating conditions, continuous operation starts from the filtered water side vacuum filtration method. After about 400 hours, the membrane differential pressure reached 80 kPa, so switching to composite filtration. Stable filtration is continued for about 2,000 hours, about 2,500 small 140,666.doc 27-201100,161 kPa (after the reference, the membrane pressure becomes 2, 10). [Comparative Example 3] A river having an average turbidity of 0.1 degree was used as a raw water. The apparatus having the same configuration as that of Comparative Example 1 was subjected to the operation and the backwashing operation, and the filtration operation was carried out by pressurizing the raw water side. The number is set to be the primary pressure regulating filter pump 3 with a fixed flow rate ' ^ ' 篁 (膘 filtration flux is 5.0 m3 / m " 曰, every 1 m2 membrane area can get 5 〇 3 k per 1 day The flow rate is supplied to the membrane module 4 by the flow rate of the raw water 1, and the Sun/En is carried out by the end point filtration method. As the operating conditions of Comparative Example 3, the filtration operation was carried out for 29 minutes, and the backwashing and gas cleaning were performed as the backwashing operation for a minute and the discharge was performed for a second. The backwashing operation was carried out at 3·8 m3/m2/day, and the oxidizing agent feed pump 9 was used to supply the sodium hypochlorite in the oxidizing agent tank 8, so that the residual gas concentration of the backwash water was 3 mg/liter. The gas system for gas cleaning uses air compressed by a compressor ίο, and the air flow rate is set to 15 Nm3/hr. Continuous operation under the above operating conditions resulted in a stable operation time, and after about 1900 hours, the differential pressure of the membrane became 2 〇〇 kpa (see Fig. 10) which required chemical cleaning. [Example 3] A backwashing wastewater of a river water sand filter having an average turbidity of 1 Torr was used as raw water. The filtration operation and the backwashing operation are carried out using a device having the same configuration as that of the embodiment, and the filtration operation is started by filtering the water side to filter under reduced pressure, and the measured value of the membrane filtration flux measuring device 13 is lower than that of the designed membrane filtration flux. 1. When 〇m3/m2/day, it will automatically switch to composite over. The decompression of the composite filtration is 140666.doc -28- 201100161; the rotation speed of the fruit 5 is 50 Hz of the maximum speed. The composite filtration system is set to use a pressure-regulating filter, and the pump 3 supplies a raw water to the crucible assembly 4 at a fixed flow rate (the membrane filtration flux is 1 〇曰 'the flow rate of 丨〇m3 filtered water per 1 m 2 of the membrane area per day). At the same time, the constant flow rate filtration under reduced pressure by the vacuum filter pump 5 is carried out by the end point filtration method. As the operating conditions of Example 3, the filtration operation was carried out for 29 minutes, and the backwashing and the gas washing were performed as the backwashing operation for 1 minute and the discharge was repeated for 30 seconds. The backwashing operation was carried out at 丨〇 m3/rn2/day, while the sulfonate feed pump 9 was used to supply the sodium sulfoxide in the oxidizer tank 8, so that the residual gas concentration of the backwash water was 3 mg/liter. The gas system for gas cleaning uses the air "air flow" compressed by the compressor 10 to be set to 丨5 Nm3/hr. Under the above operating conditions, continuous operation was started from the filtered water side vacuum filtration method. As a result, the measured value of the membrane filtration flux meter 丨3 was lower than the designed membrane filtration flux after about 2250 hours. 〇m3/m2/ Day 'Automatically switch to composite over-consideration. After about 3,000 hours, the film differential pressure becomes 2 kPa (see Fig. 1) that can be chemically cleaned (can be 1 〇m3/m2/day design membrane filtration flux operation ^ about 3000 hours (refer to Fig. 12) . [Comparative Example 4] Backwashing wastewater of a river water sand filter having an average turbidity of 100 degrees was used as raw water. The transition operation and the backwashing operation were carried out using a device having the same configuration as that of Comparative Example 1. The filtration operation was carried out by filtration under reduced pressure on the filtered water side. It is set to use the pressure regulating filter pump 3 to fix the flow rate (the membrane filtration flux is ι·〇m /m / day 'mother 1 day mother lm membrane area can obtain the flow rate of i.〇m3 filtered water) to the membrane module 4 The original water 1 was supplied, and the decompression was carried out by depressurization and decompression. 140666.doc -29- 201100161 The flow filtration was carried out by the end point filtration method as the operating condition of Comparative Example 4, and the U filtration operation was performed for 29 minutes. At the same time as the washing operation, the backwashing and the gas master ',, ', body, / month wash for 1 minute, discharge for 30 seconds and repeat the order. The backwashing operation is carried out on a daily basis. The oxidizing agent delivers the sodium to the oxidized _8 towel, and the residual chlorine concentration in the backwash water reaches 3 mg/liter. The air system used for the cleaning and the main δ ^ ritual cleaning uses the air compressed by the compressor 10, and the name of the second milk flow system is set to 1.5 Nm3/hi·. Continuous operation under the above operating conditions, the last name, ', ° membrane filtration flux after about 23 hrs is lower than the design membrane filtration flux 1 〇 3 υ · υ m / m2 / day, about 3 〇〇〇 small It is 0.45 m3/m2/曰 (Fig. 12). [Comparative Example 5] Backwashing wastewater of a river water sand filter having an average turbidity of 1 () (degree) was used as raw water. The overfishing operation and the backwashing operation were carried out using a device having the same configuration as that of Comparative Example 1, and the transient operation was carried out by a pressure transition on the raw water side. The basin system 2 is set to use the pressure regulating filter pump 3 to fix the flow rate (membrane transition flux machine. mW/day, the flow rate of the iW over the perm lm2 per i day) can be supplied to the membrane module 4 Constant flow filtering is performed in the form of an endpoint transition. As the operating conditions of Comparative Example 5, the backwashing operation was carried out for 29 minutes, the backwashing as the backwashing operation, the gas washing for 1 minute, the discharge for 30 seconds, and the reverse washing operation was performed at 1·0 m3/m2/day. At the same time, the oxidant liquid supply pump 9 is used to supply the sodium hypogasate in the oxidant tank 8, so that the residual gas concentration of the backwash water reaches 3 mg/liter. The gas system for gas cleaning uses air compressed by the compressor 10, and the air flow rate is set to 丨5 NmVhr. 140666. doc 30-201100161 Continuous operation under the above operating conditions, as a result, after about 1950 hours, the film differential pressure became 2 kPa (see Fig. 11) where chemical cleaning was necessary. [Example 4] A river surface water having an average turbidity of 2 degrees was used as raw water. The filtration operation and the backwashing operation were carried out using a device having the same configuration as that of Example 1, and the transient operation was started by filtration under reduced pressure on the filtered water side, from when the measured value of the membrane differential pressure measuring device 12 reached 8 kPa. , automatically switch to composite filtering. The rotational speed of the vacuum filtration pump 5 of the combined filtration is such that the filtration water side is continuously decompressed and the membrane differential pressure reaches a value of 80 kPa. The composite filtration system is set to use a pressure-regulating transition pump 3 at a fixed flow rate (membrane filtration flux is .7 m3/m2/day, and a flow rate of 丨7 m3 of filtered water per 1 m2 of membrane area per day) The constant flow rate filtration in which the unit 4 is supplied with the raw water 1 and the pressure reduction pump 5 is used for decompression is performed by a point-by-point method. As the operating condition of Example 4, backwashing and gas cleaning were performed while performing a filtration operation for μ minutes as a backwashing operation! Minutes, discharge for 3 seconds and ◎ repeat. The backwashing operation was carried out at 1.7 m3/m2/day while the oxidizing agent feed pump 9 was used to supply the sodium hypochlorite in the oxidizing agent tank 8, so that the residual chlorine concentration of the backwash water was 3 mg/liter. The gas system for gas cleaning uses air compressed by the compressor 10, and the air flow rate is set to 1.5 Nm3/hr. Under the above operating conditions, continuous operation was started from the filtered water side vacuum filtration method. The result was 100 kPa after 100 hours. After 100 hours, the turbidity was added to bring the turbidity to about 1 Torr, and as a result, the membrane differential pressure was increased to a maximum of 73 kPa, and then decreased. After 250 hours, the turbidity was added again to make the turbidity 1 degree. After about 260 hours (after about 10 hours from the addition of turbidity), the membrane pressure reached 80 140666.doc -31 · 201100161 kPa, so the automatic switching Into composite filtration. The membrane differential pressure rises to “ο kPa at most, and then decreases. After 500 hours, it becomes 63 kpa (refer to Figure 3). The membrane can be filtered for 1.7 m3/m2/曰 for 5 hours (see figure) [Example 6] A river surface water having an average turbidity of 2 degrees was used as the raw water. The filtration operation and the backwashing operation were carried out using a device having the same configuration as in Example 1, and the filtration operation was performed by filtering the water side to filter under reduced pressure. It is set to use a pressure-regulating filter pump 3 at a fixed flow rate (membrane filtration flux is 17 m3/m2/day per μm per 1 m2 membrane area to obtain L〇^ filtered water flow rate) to membrane module 4 The constant flow rate filtration was carried out by supplying the raw water 1 and decompressing the pressure-reducing pump 5 by the end point filtration method. As the operating conditions of the example 6, the filtration operation was carried out for 29 minutes, and the backwashing operation was carried out simultaneously. Backwashing and gas cleaning are carried out for a few minutes and discharged for 3 seconds. The backwashing operation is performed at 丨7 m3/m2/day, and the oxidant liquid feeding pump 9 is used to supply the sodium sulfoxide in the oxidizing agent tank 8, so that The residual gas concentration of the backwash water reaches 3 mg / liter. Gas cleaning The gas system using the air compressed by the compressor 10 was set to 1.5 NmVhr. 连续 Continuous operation under the above operating conditions, the film differential pressure became 45 kPa after i 〇〇 hours. After the turbidity was added after an hour, the turbidity was about 1 〇〇, and the membrane differential pressure was increased to 69 kPa at the maximum. (Refer to Fig. u). After 250 hours, the turbidity was again added to make the turbidity 1 〇〇. After about 26 hours (after about 10 hours from the addition of 3 turbidity), the membrane filtration flux is lower than the designed membrane filtration flux of 17 m / m / 曰, and the ratio is 〇 a m3 / m2 / day (refer to Figure 14). [Comparative Example 7] 140666.doc -32- 201100161 The river surface water having an average turbidity of 2 degrees was used as the raw water. The filtration operation and the backwashing operation were carried out using a device having the same configuration as that of Comparative Example 1, and the filtration operation system was used. It is carried out by pressure filtration on the raw water side. It is set to use a pressure-regulating filter pump 3 at a fixed flow rate (membrane filtration flux is 1.7 m3/m2/day, and 丨7 m3 of filtered water per 1 m of membrane area per la Flow rate) The flow rate filtration of the raw material 1 to the membrane module* is performed by the end point filtration method. As the operating conditions of Comparative Example 7, the filtration operation was carried out for 29 minutes, and the backwashing and gas washing were performed as the backwashing operation for a minute, and the discharge was performed for one second.

Repeatedly. The backwashing operation was carried out at 丨7 m3/m2/day, and the oxidizing agent feed pump 9 was used to supply the sodium hypochlorite in the oxidizing agent tank 8, so that the residual gas/agricultural degree of the backwash water was 3 . The gas system for gas cleaning uses air compressed by the compressor 10, and the air flow rate is set to i.5 Nm3/hr. Under the above operating conditions, continuous (four), the film changes after (10) hours: after 100 hours, the turbidity is added to make the turbidity about 1 (10) degrees, the maximum pressure rises to 113 kPa, and then falls (refer to Figure 3) ). After 25 〇J, the turbidity was added again to make the turbidity (10) degree: the result was about small secretion = after about 15 hours after the addition of turbidity, and the membrane pressure became 200 kPa for chemical cleaning (refer to the figure). 13). [Industrial Applicability] The present invention can be preferably used for tap water, industrial water, river water, lake water, ground water, sorrow, one, / water treatment water, wastewater, sewage, etc.! : Water is used for membrane transition or membrane separation is applied for separation or concentration of valuables [Simplified description of the drawings] 140666.doc -33· 201100161 FIG. 1 is a diagram showing the switchable raw water side pressure filtration of the embodiment of the present invention, FIG. 2 is an explanatory view showing a flow path of a fluid in a filtration step in which a raw water side is excessively pressurized in a membrane filtration device according to the present embodiment. FIG. Figure 3 is an explanatory view showing the flow of the fluid in the filtration step of the filtered water side vacuum filtration or the filtration step of the composite filtration; Fig. 4 is a view showing the cleaning of the backwash and the gas cleaning while the filtered water side is pressurized and backwashed; FIG. 5 is an explanatory view showing the flow of the fluid in the washing step of the backwashing and the gas washing at the same time as the raw water side decompression backwashing or the compound backwashing; FIG. 6 is a view showing the flow of the fluid in the washing step of the backwashing and the compound backwashing; FIG. 7 is a view showing the film differential pressure change characteristics of Example 1, Comparative Example 1, and Comparative Example 2; FIG. 8 is a view showing an example of the flow of the fluid in the step of discharging the removed material to be removed. 1. Comparison of turbidity change characteristics of Comparative Example 1 and Comparative Example 2; Fig. 9 is a view showing changes in membrane filtration flux of Examples 1, Comparative Example 1, and Comparative Example 2; Fig. 10 shows Example 2 Fig. 11 is a view showing the film differential pressure change characteristics of Example 3, Comparative Example 4, and Comparative Example 5; Fig. 12 is a view showing Example 3, Comparative Example 4, and Comparative Example. Figure 5 shows the change in membrane filtration flux characteristics; 140666.doc -34- 201100161 Figure 表示 shows a graph of film differential pressure change characteristics of Example 4, Comparative Example 6, and Comparative Example 7; and Figure I4 shows Example 4 Comparison of the filtration flux change characteristics of Comparative Example 6 and Comparative Example 7. [Main component symbol description] I Raw water 3 Pressure regulating filter pump (2nd adjustment mechanism) 4 Membrane module Ο 5 Vacuum filter pump (1st adjustment mechanism) II Water quality measuring device (measurement mechanism) 40 Control unit (control mechanism) 5 Diaphragm filtration device 140666.doc -35·

Claims (1)

201100161 VII. Patent application scope: 1. A filtering method, which is characterized in that: by performing a pressure operation as a driving force on a membrane module, a raw water is obtained by filtering raw water; and the filtering operation includes Raw water side pressure over-pressure, over-water side decompression filtration, and combination of the above-mentioned raw water side pressure filtration and the above-mentioned filtration water side pressure filtration combined filtration, measuring raw water side water quality, membrane filtration flux, and membrane At least one of the differential pressures 'switches from one of the above three modes to another filter according to the measured value. 2. The filtering method according to claim 1, wherein the measured value is a characteristic value X′ indicating a concentration of the membrane contamination causing substance calculated from the raw water side water quality, when the characteristic value X is lower than a predetermined threshold value. When the above-described raw water side pressure filtration is performed, when the characteristic value X is higher than the above-described critical value, the pressure conversion from the raw water side is switched to the above composite transition. 3. The filtration method according to claim 2, wherein the characteristic value 算出 is calculated from at least one of a raw water side turbidity A (degree) and a raw water side total organic carbon amount (mg/L). 4. The filtration method according to claim 3, wherein the above characteristic value X is χ=Α+ when the turbidity of the raw water side is A (degree) and the total organic carbon amount of the raw water side is B (mg/L). I figured it out. 5. The filtration method according to claim 1, wherein the measured value is a membrane filtration flux in a constant flow filtration operation using a designed flow rate of the filtered water side pressure reduction filtration, wherein the measured value is lower than a predetermined membrane filtration In the case of the flux 140666.doc 201100161, the filtered water side pressure reduction filtration is switched to the raw water side pressure filtration or the above composite filtration. 6. The filtration method according to claim 1, wherein the measured value corresponds to a suction lift force on the filtered water side of the membrane differential pressure, and in a constant flow transition operation using a design flow rate of the filtered water side reduced pressure filtration, When the suction lift force on the filtered water side reaches the effective NPSH, the filtered water side pressure reduction filtration is switched to the raw water side pressure overpressure or the above composite enthalpy. The filtration method according to any one of claims 1 to 6, wherein the filtering operation and the backwashing operation are alternately repeated, and the backwashing operation is performed simultaneously from the filtered water side of the membrane module to the raw water side. Washing, and cleaning the gas of the above membrane module. 8. The filtration method according to claim 7, wherein the pressure backwashing is performed from the filtered water side pressurization when the backwashing operation is performed. 9. The filtration method according to claim 7, wherein the pressure-reducing backwashing of the raw water side is performed by performing the above-described backwashing operation. 1. The filtration method according to claim 7, wherein in the case of performing the above-described backwashing operation, a composite backwash which combines pressure backwashing from the filtered water side pressure and pressure backwashing on the raw water side pressure is performed. 11. The filtration method according to claim 7, wherein the pressure backwashing from the filtered water side pressurization, the pressure backwashing on the raw water side decompression, and the pressure backwashing combined with the self-filtering water side pressurization are selected. For any of the backwashing operations of the reduced pressure backwashing of the raw water side, in the case of performing the backwashing operation, the pressure backwashing, 140666.doc 201100161, the above-mentioned reduced pressure backwashing, and the above composite are selected. Any of the backwashes. 12. A membrane filtration device comprising: a membrane module having a pressure as a driving force; and comprising: a first pressure regulating mechanism that adjusts a pressure of a raw water side of the membrane module; and a second pressure regulating mechanism Adjusting the filtered water side pressure of the membrane module; measuring the water quality of the raw water side of the membrane module; and controlling a mechanism for driving the first pressure regulating according to the measured value measured by the measuring mechanism The mechanism and the second pressure regulating mechanism are reduced to each other; and the control mechanism is configured to perform pressure filtration on the raw water side, filtration water side pressure filtration, and the raw water side pressure filtration and the filtration water side pressure reduction filtration. In the two aspects, switching from one filter to another. 13. The membrane filtration device according to claim 12, wherein the second pressure regulating mechanism is a pressure reducing pump, and the measuring means is at least one of a turbidity meter and a total organic carbon amount measuring device. The membrane filtration device according to claim 12 or 13, wherein the control means drives and controls at least one of the first pressure regulating mechanism and the second pressure regulating mechanism to perform pressure backwashing of the filtered water side pressure, Any of the composite backwashing of the decompression of the raw water side depressurization, backwashing, and the combination of the backwashing of the filtered water side and the pressure backwashing of the raw water side depressurization. 140666.doc