Flat membrane testing device and flat membrane testing method

Abstract

It allows for membrane filtration and cleaning of the membrane after filtration. [Solution] The flat membrane testing device 100 has a membrane and a filtrate outlet 1A at one end of a cylindrical liquid-passing pipe 1E for discharging filtered wastewater, and a cleaning liquid injection port 1B at the other end for introducing cleaning liquid. It also has a filtration section 1 having an inlet / outlet 1C at the side wall of the liquid-passing pipe 1E for introducing raw liquid 73 during raw liquid treatment and for discharging cleaning liquid during cleaning, and a drive section for rotating the filtration section 1 by 90 degrees. In the filtration step, an orientation change mechanism 4 positions the pipe vertically with the filtrate outlet 1A at the bottom and the cleaning liquid injection port 1B at the top, and in the cleaning step, it positions the liquid-passing pipe 1E horizontally with the inlet / outlet 1C at the bottom.

Description

[Technical Field]

[0001] The present invention relates to a flat membrane testing device and a flat membrane testing method for raw liquids such as process liquids. [Background technology]

[0002] Membrane filtration technology is used in a variety of fields, including the electronics and food industries, as well as pharmaceutical, bio, and chemical industries. When designing and building a system that uses membrane filtration technology, it is important to conduct evaluation tests to confirm the various membrane performance characteristics using the raw liquid that will actually be treated, and to obtain information about the operating conditions in the actual process.

[0003] Patent Document 1 discloses a flat membrane testing device and a flat membrane testing method that enable comparison without taking into account relative errors due to different measurement systems, even when there are multiple test systems to be measured in a membrane evaluation device. The invention of Patent Document 1 aims to provide a flat membrane testing device that eliminates errors and enables comparison, even when multiple test systems are targeted.

[0004] Patent Document 2 discloses a separation membrane testing device that allows for easy and rapid replacement of separation membranes and disassembly of cells. The device tests the performance of separation membranes using a cross-flow filtration cell in which a flat separation membrane is installed inside, a raw solution to be treated is flowed along the membrane surface of the separation membrane, and the permeated liquid flows through the separation membrane to filter the raw solution. Here, the performance of the separation membrane is confirmed by examining the components of the concentrated liquid and the permeated liquid. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2019-166462 [Patent Document 2] Japanese Patent Application Laid-Open No. 2002-45661 Summary of the Invention [Problem to be solved by the invention]

[0006] In an actual membrane filtration process, after membrane filtration, a cleaning solution is sometimes sprayed onto the raw liquid side of the membrane to clean it, but until now, there has been no test equipment that can perform membrane filtration and cleaning of the membrane after filtration.

[0007] Therefore, an object of the present invention is to provide a flat membrane testing device and a flat membrane testing method that are capable of performing membrane filtration and cleaning of the membrane after filtration. [Means for solving the problem]

[0008] The means for solving the above problems are as follows.

[0009] (First aspect) A flat membrane testing device that performs dead-end filtration using a flat membrane and cleaning of the flat membrane after filtration. a filtration section having a membrane mounting section to which a flat membrane is attached, a cleaning liquid jetting port provided to spray a cleaning liquid onto the raw liquid side surface of the flat membrane attached to the membrane mounting section, a liquid passage pipe extending from the cleaning liquid jetting port to the membrane mounting section along the spraying direction of the cleaning liquid so as to pass the cleaning liquid, a supply / discharge port provided on a side wall of the liquid passage pipe between the cleaning liquid jetting port and the membrane mounting section for supplying the raw liquid and discharging the cleaning liquid, and a filtrate discharge port communicating with the filtrate side of the flat membrane attached to the membrane mounting section; an orientation change mechanism that changes the orientation of the filtration unit between a filtration state in which the cleaning liquid jetting port is located at an upper position and the liquid passage pipe is oriented vertically and a cleaning state in which the supply / discharge port is located at a lower position and the liquid passage pipe is oriented horizontally; a raw liquid supply unit that supplies raw liquid to the supply / discharge port; a cleaning liquid supply unit that supplies cleaning liquid to the cleaning liquid jetting port; Equipped with A flat membrane testing device characterized by:

[0010] (Action and effect) A feature of this flat sheet membrane testing device is that it is possible to perform membrane filtration tests and post-filtration cleaning in sequence by changing the arrangement of the cleaning liquid injection port and supply / discharge port on the raw liquid side of the flat sheet membrane and the orientation of the filtration unit equipped with them. When conducting a filtration test, the cleaning liquid injection port is positioned at the top (i.e., the flat sheet membrane is positioned at the bottom) and the liquid passage pipe is oriented vertically in the filtration state, and the raw liquid is supplied to the supply / discharge port by the raw liquid supply unit. The raw liquid flows from the supply / discharge port into the liquid passage pipe and flows downward, and is fully filtered by the flat sheet membrane. The filtrate that has permeated the flat sheet membrane is discharged from the filtrate discharge port.

[0011] During cleaning, the orientation of the filtration section is changed from the filtration state to the cleaning state where the supply and discharge port is positioned downward and the liquid passage pipe is oriented horizontally, and then cleaning liquid is supplied to the cleaning liquid injection port by the cleaning liquid supply section. The cleaning liquid is sprayed from the cleaning liquid injection port onto the raw liquid side of the flat membrane, cleaning the flat membrane. The cleaning liquid is then discharged from the supply and discharge port.

[0012] (Second aspect) the orientation change mechanism is a drive unit that changes the orientation of the filtration unit by power, a measuring unit that automatically measures at least one of a filtration flow rate and a filtration differential pressure; a control unit that, when detecting that the measurement value of the measurement unit has reached a predetermined value, stops the raw liquid supply unit, drives the drive unit to change the orientation of the filtration unit from the filtration state to the cleaning state, and then starts the cleaning liquid supply unit; The flat membrane testing device according to the first aspect, further comprising:

[0013] (Action and effect) The orientation change mechanism may be one that changes the orientation of the filtration unit manually, but is preferably a drive unit that changes the orientation of the filtration unit using power. In this case, having a control unit such as that of this embodiment is preferable because it allows automatic transition from the filtration test to the cleaning step.

[0014] (Third aspect) An activated carbon supply unit is provided which supplies activated carbon slurry to the supply and discharge port. The flat membrane test device according to the first or second aspect.

[0015] (Action and effect) In order to remove organic matter and the like from the raw solution, activated carbon may be attached to the membrane surface and used (for example, JP 2022-69280 A). In such cases, it is useful to conduct a test with activated carbon attached to the membrane surface and obtain information on the organic matter removal performance (for example, the cumulative flow rate at which organic matter in the raw solution can be treated). This embodiment makes such a test possible.

[0016] (Fourth aspect) A flat membrane testing method for performing dead-end filtration using a flat membrane and cleaning the flat membrane after filtration, a membrane mounting part to which a flat membrane is attached; a cleaning liquid jetting port provided to spray a cleaning liquid onto the raw liquid side surface of the flat membrane attached to the membrane mounting part; a liquid passage pipe extending from the cleaning liquid jetting port to the membrane mounting part along the direction of spraying of the cleaning liquid so as to pass the cleaning liquid; a supply / discharge port provided in the side wall of the liquid passage pipe between the cleaning liquid jetting port and the membrane mounting part for supplying the raw liquid and discharging the cleaning liquid; and a filtrate discharge port communicating with the filtrate side of the flat membrane attached to the membrane mounting part, A membrane mounting step of mounting a flat membrane to the membrane mounting portion; a filtration step in which the filtration unit is placed in a filtering state in which the cleaning liquid jetting port is positioned at an upper position and the liquid passage pipe is oriented vertically, the raw liquid is supplied from the supply / discharge port by the raw liquid supply unit, and the flat membrane is subjected to total filtration, and the filtrate is discharged from the filtrate discharge path; a cleaning step in which, after the filtration step, the supply and discharge port is positioned downward and the liquid passage pipe is oriented horizontally, and a cleaning liquid is sprayed from the cleaning liquid jet port onto the raw liquid side surface of the flat membrane to clean the flat membrane, and the cleaning liquid is discharged from the supply and discharge port; A flat membrane test method comprising:

[0017] (Action and effect) This provides the same effects as the first embodiment.

[0018] (Fifth aspect) After the membrane attachment step and before the filtration step, and an activated carbon impregnation step of: positioning the filtration unit so that the cleaning liquid injection port is positioned at an upper position and the liquid passage pipe is oriented vertically; supplying activated carbon slurry to the supply / discharge port to perform full-volume filtration by the flat membrane; impregnating activated carbon onto a surface of the flat membrane attached to the membrane attachment unit facing the cleaning liquid injection port; and discharging the filtrate from the filtrate discharge path. The flat membrane test method according to the fourth aspect.

[0019] (Action and effect) This provides the same effects as the third embodiment.

[0020] (Sixth aspect) In the cleaning step, the cleaning liquid contains cleaning powder and granules. The flat membrane test method according to the fourth or fifth aspect.

[0021] (Action and effect) Suspended matter in the raw solution is captured by the flat membrane being tested. In this case, it may be difficult to completely remove the trapped suspended matter by simply spraying a cleaning solution. In such cases, it is effective to spray a cleaning solution containing cleaning powder. [Effects of the Invention]

[0022] According to the present invention, it is possible to perform membrane filtration and cleaning of the membrane after filtration in a flat membrane testing device. [Brief explanation of the drawings]

[0023] [Figure 1] FIG. 1 is a schematic diagram of the entire device. [Figure 2] FIG. 1 is a schematic diagram illustrating a filtration step. [Figure 3] FIG. 1 is a schematic diagram showing a washing step after a filtration step. [Figure 4A] FIG. 10 is a cross-sectional view passing through the central axis of the filtration section during the filtration step. [Figure 4B]FIG. 10 is a cross-sectional view passing through the central axis of the filtration section during the filtration step when activated carbon is impregnated. [Figure 4C] FIG. 10 is a cross-sectional view passing through the central axis of the filtration section during the cleaning step. [Figure 5] FIG. 1 is a block diagram of a flat membrane testing device. [Figure 6] FIG. 1 is a flow diagram of a flat membrane test method. DETAILED DESCRIPTION OF THE INVENTION

[0024] An example of the flat membrane testing device 100 and its testing method will be described below with reference to the drawings. Note that the following description and drawings merely show one example of the present invention, and the contents of the present invention should not be interpreted as being limited to this embodiment.

[0025] (Flat membrane testing equipment) 5 shows an example of the configuration of a flat membrane testing device 100. This flat membrane testing device 100 has a main part 101, a control part 102, a measuring part 103, and a recording part 104. As shown in Figure 1, the main part 101 has, as its main components, a filtration part 1 in which a test flat membrane 70 is mounted, an orientation change mechanism 4 that changes the orientation of the filtration part 1, a raw liquid supply part 101S that supplies raw liquid to the filtration part 1, and a cleaning liquid supply part 101C that supplies a cleaning liquid such as clean water to the filtration part 1.

[0026] The filtration section 1 comprises a membrane mounting section 1D to which the flat membrane 70 is attached, a cleaning liquid nozzle 1B arranged to spray cleaning liquid onto the raw liquid side surface of the flat membrane 70 attached to the membrane mounting section 1D, a liquid passage pipe 1E extending from the cleaning liquid nozzle 1B to the membrane mounting section 1D along the spraying direction of the cleaning liquid so as to pass the cleaning liquid, a supply / discharge port 1C provided on the side wall of the liquid passage pipe 1E between the cleaning liquid nozzle 1B and the membrane mounting section 1D for supplying the raw liquid 73 and discharging the cleaning liquid, and a filtrate discharge port 1A connected to the filtrate side of the flat membrane 70 attached to the membrane mounting section 1D. More specifically, the filtration unit 1 in the illustrated example includes a cylindrical liquid passage tube 1E, a first cover 1F attached to the opening at one end of the liquid passage tube 1E and having a filtrate outlet 1A in its center, a second cover 1G attached to the opening at the other end of the liquid passage tube 1E and having a cleaning liquid injection port 1B in its center, and an inlet / outlet port 1C provided in the side wall of the liquid passage tube 1E. The surface of the first cover 1F facing the second cover 1G is covered with a liquid passage plate 71 such as a flat mesh or punched metal that supports a flat membrane 70, allowing the entire peripheral edge of the flat membrane 70 to be sandwiched and fixed between one end of the liquid passage tube 1E and the first cover 1F. In other words, one end of the liquid passage tube 1E and the first cover 1F form a membrane mounting part 1D, and the flat membrane 70 attached to the membrane mounting part 1D is fixed in an orientation along a direction perpendicular (transverse direction) to the central axis of the liquid passage tube 1E.

[0027] The orientation change mechanism 4 is not particularly limited as long as it can change the orientation of the filtration unit 1 between a filtration state in which the cleaning liquid jet nozzle 1B is located at the top and the liquid passage pipe 1E is oriented vertically and a cleaning state in which the supply / discharge port 1C is located at the bottom and the liquid passage pipe 1E is oriented horizontally. However, it is preferable that the filtration unit 1 be rotated forward and backward by a rotation angle of 90 degrees about a horizontal rotation axis that is approximately horizontal, thereby selecting between a filtration state in which the filtrate discharge port 1A is located at the bottom and the liquid passage pipe 1E is oriented substantially vertically and a cleaning state in which the supply / discharge port 1C is located at the bottom and the liquid passage pipe 1E is oriented substantially horizontally. The orientation change mechanism 4 may be manually operated to change the orientation of the filtration unit 1, but is preferably a drive unit 4 that uses power to change the orientation of the filtration unit 1. In the illustrated example, the drive unit 4 is an actuator driven by compressed air PA, and the control valve 5 switches the supply of compressed air PA to drive the drive unit 4. However, this is not limited to this, and other actuators may be used.

[0028] The raw liquid supply unit 101S is not particularly limited as long as it can supply the raw liquid under pressure to the supply and discharge port 1C, but as in the illustrated example, it can include a raw liquid tank 20 connected to the supply and discharge port 1C by piping 83, an solenoid valve 21 interposed in the piping 83, a supply source of compressed air PA (not shown), a piping 88 for supplying the compressed air PA to the raw liquid tank 20, a first air supply valve 26, a first air purge valve 25, and a second air supply valve 23 interposed in this order in the piping 88 from the supply source of compressed air PA toward the raw liquid tank 20, and a third pressure gauge 24 attached between the first air purge valve 25 and the second air supply valve 23 in the piping 88.

[0029] The configuration of the filtrate discharge system from the filtrate discharge port 1A is not particularly limited, but as shown in the illustrated example, it is preferable that a pipe 81 is connected to the filtrate discharge port 1A and that a filtrate on-off valve 11 and a drain throttle valve 13 are interposed in this order in this pipe 81.

[0030] The cleaning liquid supply unit 101C is not particularly limited as long as it can supply cleaning liquid such as fresh water under pressure to the cleaning liquid jetting nozzle 1B, but in the illustrated example, it includes a cleaning tank 40 connected to the cleaning liquid jetting nozzle 1B by a pipe 82, a solenoid valve 6 interposed in the pipe 82, a supply source of compressed air PA (not shown), a pipe 86 for supplying the compressed air PA to the cleaning tank 40, a third air supply valve 41, a second air purge valve 42, and a fourth air supply valve 44 interposed in this order in the pipe 86 from the supply source of compressed air PA toward the cleaning tank 40, and a fourth pressure gauge 43 attached to the pipe 86 between the second air purge valve 42 and the fourth air supply valve 44. The cleaning liquid supply unit 101C in the illustrated example also includes a ventilated air pipe branching from between the second air purge valve 42 and the fourth air supply valve 44 and connected to the cleaning liquid jetting nozzle 1B, and a ventilated air supply valve 15 interposed in the ventilated air pipe.

[0031] The configuration of the cleaning liquid discharge system from the supply and discharge port 1C is not particularly limited, but as shown in the example, it can have a collection tank 50 such as a pail for collecting cleaning liquid, a pipe 84 connected to the supply and discharge port 1C and discharging the cleaning water discharged from the supply and discharge port 1C into the collection tank 50, and an electromagnetic valve 22 interposed in this pipe 84.

[0032] The flat membrane testing apparatus 100 is also preferably equipped with an activated carbon supply unit 101A that supplies activated carbon slurry to the inlet / outlet 1C. The configuration of the activated carbon supply unit 101A is not particularly limited as long as it can supply activated carbon slurry under pressure to the inlet / outlet 1C, but as shown in the example shown, it can include an activated carbon slurry tank 30 connected to the inlet / outlet 1C by a pipe 85, an activated carbon impregnation valve 31 interposed in the pipe 85, a pipe 87 branching from between the third pressure gauge 24 and the second air supply valve 23 in the pipe 88 of the raw solution supply unit 101S described above and connected to the activated carbon slurry tank 30, and an impregnation air supply valve 27 interposed in this pipe 87. In the illustrated example, the supply system for compressed air PA upstream of the impregnation air supply valve 27 is configured to be shared with the raw liquid supply unit 101S, but a supply system for compressed air PA for activated carbon impregnation may be provided separately from the raw liquid supply unit 101S.

[0033] Although not shown, the activated carbon supply unit 101A may have a slurry preparation unit that disperses activated carbon in water, etc., in which case the activated carbon slurry tank 30 may be omitted and the prepared slurry may be directly supplied.

[0034] The measuring unit 103 is not particularly limited as long as it measures test data. For example, the measuring unit 103 can be selected from a pressure gauge, flow meter, pH meter, turbidity meter, TOC meter, or the like, as needed depending on the test content. When measuring the filtration flow rate, a flow meter 12 can be provided to measure the flow rate at an appropriate location in the filtrate discharge line (in the illustrated example, between the filtrate on-off valve 11 and the drain throttle valve 13 in the piping 81). When measuring the filtration differential pressure, a first pressure meter 9 can be provided to measure the pressure at an appropriate location in the raw liquid supply system (in the illustrated example, between the solenoid valve 21 and the supply / discharge port 1C), and a second pressure meter 10 can be provided to measure the pressure at an appropriate location in the filtrate discharge line (in the illustrated example, between the filtrate outlet 1A and the filtrate on-off valve 11 in the piping 81).

[0035] The flat membrane testing apparatus 100 is preferably configured to automatically perform all processes (from the start operation to the end of the test), including switching between passing the stock solution through the flat membrane 70 (filtration step) and cleaning with a cleaning solution (cleaning step), by controlling the opening and closing of each valve and the change in orientation of the filtration unit 1 using the control unit 102; however, some or all of the processes may be performed manually. The flat membrane testing apparatus 100 may perform the filtration step and the cleaning step once each, or may repeat the filtration step and the cleaning step as one cycle a predetermined number of times. As will be seen from the examples described below, the control unit 102 monitors the measurement results of the measurement unit 103 and, depending on the measurement results, can control the opening and closing of each valve and the change in orientation of the filtration unit 1 so that the filtration step and the cleaning step are repeated a predetermined number of times. For example, by monitoring the filtration differential pressure and the filtration flow rate, information regarding the appropriate stock solution flow rate and cleaning conditions can be obtained.

[0036] The control unit 102 can be configured using a known industrial control device, such as a sequencer (PLC) or a computer (PC, microcontroller), either singly or in combination depending on the function. For example, the basic control and interface of conveyors, sensors, robots, etc. can be realized by a sequencer, while information processing and commands to the sequencer based on the information (mode setting, parameter setting, operation start command, etc.) can be realized by a computer. Physically, a computer can include a central processing unit (CPU), main storage devices such as random access memory (RAM) and read-only memory (ROM), a communication module, and auxiliary storage devices. When a computer is used, control by the control unit can be realized by loading specific computer software into the CPU or RAM, operating various hardware under the control of the CPU, and reading and writing data from and to the RAM. The recording unit 104 can be an auxiliary storage device or a printing device built into or connected to the control unit.

[0037] In the following, a repeated operation of the filtration step and the washing step without the activated carbon being attached to the flat membrane 70 will be described. (filtration step) A schematic diagram of the filtration step is shown in Figure 2. The overall process flow is shown in Figure 5. In the filtration step, the filtration unit 1 is positioned vertically with the filtrate outlet 1A at the bottom and the cleaning liquid injection port 1B at the top (S201). The first air supply valve 26 is opened, and a predetermined set pressure is set by the first air purge valve 25. The predetermined set pressure is, for example, 50 kPa. The second air supply valve 23 is opened. The selector valve 5 is closed, and the filtrate on-off valve 11 is opened. The filtration button provided in the control unit 102 is turned on, the solenoid valve 21 is opened, and the solenoid valves 22 and 6 are closed. As a result, the raw liquid is sent from the raw liquid tank 20 to the filtration unit 1 through the supply / discharge port 1C, and filtration begins (S201).

[0038] Examples of the raw solution according to the present invention include drainage water from tunnel premises, wastewater from a ready-mixed concrete plant for spraying, wastewater from die slime recovery, batcher plant wastewater, dry pit wastewater from river construction, drainage water from deep foundation construction, grouting construction wastewater, shield construction wastewater, excess shield mud water, dredging and landfill wastewater, caisson construction wastewater, cast-in-place pile wastewater, floor cleaning wastewater, well point construction wastewater, foundation construction yard wastewater, tire cleaning wastewater, core boring wastewater, diamond cutter wastewater, soil contamination excavation yard wastewater, VOC decomposition cleaning wastewater, incinerator demolition cleaning wastewater, radioactive decontamination work wastewater, wire saw cutting work wastewater, water jet cutting work wastewater, paper mill process wastewater, pulp mill process wastewater, food factory cleaning wastewater, ready-mixed concrete factory cleaning wastewater, concrete secondary product factory wastewater, and crushed stone factory Examples of effluents include yard wastewater, gas cleaning scrubber wastewater, waste incinerator quenching tower wastewater, converter gas cleaning wastewater, arc furnace gas cleaning wastewater, silver recovery process wastewater, sand washing device wastewater, water washing neutralization wastewater, barrel polishing wastewater, electrolytic polishing wastewater, glass polishing wastewater, wet blasting wastewater, spray painting booth wastewater, cationic coating wastewater, stainless steel pickling wastewater, raw material yard wastewater, raw material conveyor cleaning wastewater, sediment dust wet recovery wastewater, factory yard wastewater, continuous casting wastewater, rolling cooling wastewater, dehumidification drainage, immersion cutting yard wastewater, slag yard wastewater, ship bottom bilge wastewater, shipbuilding dock wastewater, shell removal wastewater, cooling tower blowdown wastewater, dyeing factory wastewater, milk plant cleaning wastewater, tunnel wall cleaning wastewater, building exterior wall cleaning wastewater, car wash wastewater, golf course wastewater, industrial disposal site leachate, and organic-containing wastewater.

[0039] At this time, the inside of the filtration unit 1 has air above it, and is not entirely filled with the raw liquid. Therefore, for example, if the filtration unit 1 is positioned sideways or horizontally during the filtration step, filtration will not occur above the flat membrane 70, and filtration will not occur uniformly across the entire installed flat membrane 70, making accurate evaluation impossible. Furthermore, if evaluation is performed with the impregnated activated carbon 72 impregnated on the flat membrane 70, the layer of the impregnated activated carbon 72 may become uneven due to the influence of gravity. For this reason, during the filtration step, the filtration unit 1 is positioned vertically or vertically with the filtrate outlet 1A facing downwards.

[0040] The filtration differential pressure, which is the differential pressure of the initial filtration section pressure (the difference between the pressures indicated by the first pressure gauge 9 and the second pressure gauge 10), and the filtration flow rate, which is the flow rate (flow rate per specified time) measured by the flow meter 12, are measured by the measuring unit 103 and input into the recording unit 104 as data. As the liquid passing time passes, when the filtration flow rate reaches a predetermined multiple of the initial filtration flow rate, the process proceeds to the cleaning step in response to an instruction from the control unit 102. The predetermined multiple is, for example, 1 / 2 to 1 / 10 of the initial filtration flow rate. As the raw liquid passes through for a certain period of time, the filtration differential pressure indicated by the first pressure gauge 9 and the second pressure gauge 10 increases due to clogging caused by suspended solids and the like, and at the same time, the filtration flow rate decreases. When the filtration flow rate becomes, for example, 1 / 5 of the initial filtration flow rate, the filtration step is terminated (S202). Note that the filtration step may be terminated based on the filtration differential pressure instead of the filtration flow rate. In this case, the filtration differential pressure may be set to, for example, 2 to 10 times the initial filtration differential pressure.

[0041] (Cleaning process) In the cleaning step, the third air supply valve 41 is opened, and a predetermined set pressure is set by the second air purge valve 42. The predetermined set pressure is, for example, 100 kPa. Also, the fourth air supply valve 44 is opened. In response to an instruction from the control unit 102, the driving unit 4 automatically rotates the filtration unit 1 so that the inlet / outlet 1C is positioned downward and the liquid passage pipe 1E is oriented sideways, and the filtration unit 1 is positioned horizontally with the inlet / outlet 1C facing downward (S203). In addition, the solenoid valve 21 is automatically closed and the solenoid valve 22 is automatically opened. At this time, the raw liquid remaining in the liquid passage pipe 1E of the filtration unit 1 is discharged from the inlet / outlet 1C, and the filtration unit 1 becomes free of liquid. Furthermore, the solenoid valve 6 is opened for a predetermined time, and the cleaning liquid is introduced from the cleaning liquid injection port 1B. Under these conditions, the cleaning liquid introduced from the cleaning liquid injection port 1B is sprayed directly onto the flat membrane 70 installed on the filtrate discharge port 1A side, thereby cleaning the flat membrane 70. The opening time of the solenoid valve 6 is initially set to, for example, 2 seconds (S203). The opening time of the solenoid valve 6 is changed depending on the cleaning status. For example, if the filtration differential pressure or filtration flow rate at the time of transition to the subsequent filtration step has not recovered to the initial filtration differential pressure or filtration flow rate, the opening time of the solenoid valve 6 can be extended.

[0042] In this case, the cleaning efficiency can be improved by mixing cleaning powder granules into the cleaning liquid and spraying them onto the flat membrane 70 together with the cleaning liquid. The cleaning powder granules refer to powders and granules, and can be, for example, beads such as spherical plastic beads or spherical perlite beads, spherical sponges such as spherical PVC sponges, or sand such as silica sand. However, the cleaning powder granules are sprayed onto the flat membrane 70 in a state mixed with the cleaning liquid. Therefore, from the viewpoint of preventing deterioration of the flat membrane 70, it is not preferable for the cleaning powder granules to be angular particles such as sand, and rounded particles such as spherical particles or ellipsoidal particles are preferred. From the same viewpoint, it is also preferable that the cleaning powder granules do not have a high hardness. Specifically, the hardness of the cleaning powder granules is preferably R20 to R110. Furthermore, it is preferable that the cleaning powder granules are uniformly dispersed in the cleaning liquid. Therefore, the specific gravity of the cleaning powder granules is, for example, 0.8 to 1.2 g / cm. 3 In addition, the cleaning powder preferably has a particle size suitable for recovery and reuse, i.e., classification. Specifically, the particle size is preferably 0.2 mm to 1 mm, and more preferably 0.4 mm to 0.7 mm, but particles of the above particle sizes can also be used satisfactorily as cleaning powder. The particle size of the cleaning powder is a value measured in accordance with JIS Z8800.

[0043] When the washing waste liquid and the washing powder or granular material are used, the washing waste liquid and the washing powder or granular material are discharged through the supply / discharge port 1C and collected in the waste liquid collecting pail can 50. After the flat membrane 70 has been washed with the washing liquid, the aeration air supply valve 15 is opened for a predetermined time, and the liquid in the filtration unit 1 is drained by air (S204).

[0044] (Repeat process) In order to obtain the conditions for the membrane to be used, cleaning, etc. when actually treating process wastewater with a membrane, the above-mentioned filtration step and cleaning step can be automatically repeated. When the cycle of the filtration step and the cleaning step is completed, the first air supply valve 26, the second air supply valve 23, the filtrate on-off valve 11, the third air supply valve 41, and the fourth air supply valve 44 are open.

[0045] In response to an instruction from the control unit 102, the solenoid valve 6 is opened for a predetermined time, and the cleaning liquid is introduced through the cleaning liquid injection port 1B to clean the flat membrane 70. Subsequently, in response to an instruction from the control unit 102, the aeration air supply valve 15 is opened for a predetermined time, and the filtration unit 1 is drained with air, completing the cleaning step (S204). After the cleaning step is completed, the filtration step is performed. First, in response to an instruction from the control unit 102, the filtration unit 1 is automatically rotated by the drive unit 4 so that the cleaning liquid injection port is positioned upward and the liquid passage pipe 1E is vertically oriented, and the filtrate discharge port 1A is positioned downward, in a vertical or upright position. Next, in response to an instruction from the control unit 102, the solenoid valve 21 is opened and the solenoid valve 22 is closed. As a result, the raw liquid is sent from the raw liquid tank 20 to the filtration unit 1 through the supply / discharge port 1C, and the filtration step is initiated (S201). The filtration differential pressure and filtration flow rate in the filtration step are measured as data by the measuring unit 103 and input into the recording unit 104. The filtration flow rate is the amount of raw liquid passing through the membrane per predetermined time. For example, it is the amount of raw liquid passing through the membrane per minute. When the filtration flow rate becomes, for example, 1 / 5 of the initial filtration flow rate in the first filtration step, the filtration step is terminated by an instruction from the control unit 102 (S202). The filtration flow rate at the end of filtration can be set arbitrarily.

[0046] Next, the process automatically moves to the cleaning step. First, in response to an instruction from the control unit 102, the filtration unit 1 is automatically rotated by the drive unit 4 so that the supply / discharge port 1C is positioned downward and the liquid passage pipe 1E is positioned sideways or horizontally. Also, in response to an instruction from the control unit 102, the solenoid valve 21 is closed and the solenoid valve 22 is opened. At this time, the raw liquid remaining in the filtration unit 1 is drained, and the filtration unit 1 becomes free of liquid. Furthermore, the solenoid valve 6 is opened for a predetermined time, and the cleaning liquid is introduced from the cleaning liquid injection port 1B and injected directly onto the flat membrane 70 installed on the filtrate discharge port 1A side, thereby cleaning the flat membrane 70 (S203). At this time, the cleaning liquid may contain cleaning powder. After the flat membrane 70 is washed with the cleaning liquid, the aeration air supply valve 15 is opened for a predetermined time, and the liquid inside the filtration unit 1 is drained by air (S204). Thereafter, the driving unit 4 positions the filtration unit 1 so that the cleaning liquid jet nozzle 1B is located at the top and the liquid passage pipe 1E is oriented vertically or upright, and the process proceeds to the filtration step (S201).

[0047] As described above, the filtration step and the washing step are repeated a predetermined number of times. The number of times the filtration step and the washing step are repeated is set at the start of the test, and the test ends automatically after the set number of times is reached. The test is usually repeated about 50 to 200 times, with 100 times being a typical example. Depending on the type of raw solution, cleaning may not be enough to fully restore membrane contamination, and the filtration differential pressure may increase early in the repetition of the filtration and cleaning steps, resulting in a significant drop in filtration flow rate.For example, if the throughput drops dramatically within the first few repetitions (for example, the filtration differential pressure is 50% or more of the set pressure), consider changing the type of membrane. The trend of the filtration differential pressure or filtration flow rate immediately after the start of filtration is evaluated for each repetition, and if the filtration differential pressure or filtration flow rate is stable after, for example, 100 repetitions, it can be expected that stable operation will be possible for, for example, one year or more in the actual process under those cleaning conditions.For example, if the filtration differential pressure or filtration flow rate immediately after the start of filtration is stable within a range of 10% after 100 repetitions, it can be determined that the cleaning conditions are effective. Conversely, if, for example, after 100 repetitions, the filtration differential pressure or filtration flow rate immediately after the start of filtration shows a tendency to decrease by 10% or more, in addition to changing the cleaning conditions, consider adding a coagulant, acid solution, CO2 gas, or sodium hypochlorite to the raw water and conducting the test again. Flocculants promote the aggregation of colloidal particles in the raw solution and prevent clogging of the membrane. Acidic solutions prevent clogging of the membrane by forming particles through the precipitation action of iron ions and other substances. CO2 gas prevents clogging of the membrane by forming particles of calcium ions. Sodium hypochlorite is effective in preventing clogging when there is a large amount of organic matter such as TOC components. For example, if the filtration differential pressure or filtration flow rate immediately after the start of filtration shows a tendency to decrease by 10% or more after 100 repetitions, the above considerations will be carried out to find operating conditions that allow long-term stable operation for more than one year.

[0048] By conducting the above tests, it is possible to obtain the type of membrane used in an actual membrane treatment device, the cleaning conditions for membrane treatment, and other operating conditions.

[0049] Furthermore, when the cleaning conditions are fixed in a repeated operation test of the filtration step and the cleaning step using the flat membrane testing apparatus 100, data on the filtration flow rate and the filtration differential pressure after, for example, 100 repeated tests can be obtained. From the degree of decrease in the filtration flow rate or increase in the filtration differential pressure at this time, it becomes possible to predict to some extent the service life of the membrane in an actual machine. For example, if the filtration differential pressure or filtration flow rate is stable after 100 repetitions, and there is no tendency for the filtration differential pressure to increase or the filtration flow rate to decrease, and the difference is stable within a range of, for example, 10%, then it is determined that stable operation for more than one year is possible.

[0050] (Activated carbon impregnation test) The flat membrane testing device 100 is used to select an optimum membrane and obtain the operating conditions of the membrane when treating the process fluid in practice. When treating process fluids using membranes, activated carbon may be attached to the membrane surface to remove soluble organic matter from the raw solution. In such cases, testing with activated carbon attached to the membrane surface can provide useful information for actual operation.

[0051] The activated carbon is preferably powdered activated carbon. Its average particle size is preferably 1 to 30 μm, more preferably 5 to 9 μm. The average particle size is determined by measuring the particle size distribution using a laser diffraction / scattering particle size distribution analyzer (e.g., the LA-960V2 series, manufactured by Horiba, Ltd.), and the particle size at which the cumulative volume corresponds to 50% is defined as the average particle size. If the particle size of the activated carbon particles is smaller than 1 μm, the pressure loss increases, significantly slowing the filtration speed of the raw liquid, etc. On the other hand, if the particle size of the activated carbon particles is larger than 30 μm, diffusion into the activated carbon becomes rate-limiting, resulting in a decrease in the adsorption speed.

[0052] When the flat membrane testing apparatus 100 is operated with activated carbon impregnated therein, the method for impregnating the activated carbon can be carried out, for example, as follows. Activated carbon slurry is introduced into the activated carbon slurry tank 30 and stored therein. The air supply valve 26 is opened, and the air supply pressure is set to, for example, 50 kPa using the first air purge valve 25. The impregnation air supply valve 27, the activated carbon impregnation valve 31, and the filtrate on-off valve 11 are opened, and a predetermined amount of activated carbon is impregnated. The impregnation air supply valve 27, the activated carbon impregnation valve 31, and the filtrate on-off valve 11 are closed, and the activated carbon impregnation is completed. By this operation, a layer of impregnated activated carbon 72 is formed on the flat membrane 70, as shown in FIG. 3B. The amount of impregnated activated carbon is 100 to 1000 g / m 2 , preferably 200 to 800 g / m 2 is.

[0053] After the activated carbon is impregnated, a filtration step is performed in which the raw liquid is introduced. The details of the operation are omitted as they overlap with those explained above. Here, it is preferable to monitor the concentration of a reference substance contained in the raw liquid in the treated liquid that has passed through the impregnated activated carbon 72 and flat membrane 70. Examples of reference substances include TOC components and SS components. If the raw liquid is to be treated with PFAS (organofluorine-containing compounds), PFAS can be used as the reference substance. When the concentration of the reference substance in the filtrate reaches or exceeds a predetermined concentration, the filtration step is terminated by an instruction from the control unit 102. During this time, data such as the filtration flow rate of the raw liquid, the integrated flow rate, and the filtration differential pressure are recorded in the recording unit 104. After the filtration step is completed, the process proceeds to the cleaning step.

[0054] It is possible to predict the amount of activated carbon impregnated, the liquid flow rate, and the integrated flow rate until the reference substance breaks through in an actual system from the amount of activated carbon impregnated, the integrated flow rate at the time when the concentration of the reference substance in the filtrate reaches a predetermined concentration or higher, the liquid flow rate, etc. [Industrial Applicability]

[0055] The flat membrane testing device 100 of the present invention automatically performs the filtration step and the cleaning step using the raw liquid to be actually treated and the cleaning solution, thereby making it possible to select a membrane suitable for treating the raw liquid to be actually used and to obtain in advance the cleaning conditions for the membrane in the actual device. Furthermore, it is possible to predict the membrane life in an actual device from the changes in filtration flow rate and filtration differential pressure when the filtration step and cleaning step are repeatedly performed. This will enable smooth processing of raw liquids in actual equipment using membrane separation technology, which is used in a variety of fields to separate, refine, concentrate, and recover process fluids.

[0056] The technical scope of the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention. [Explanation of symbols]

[0057] 1...filtration section, 1A...filtrate discharge port, 1B...cleaning liquid injection port, 1C...supply / discharge port, 1D...membrane mounting section, 1E...liquid passage pipe, 1F...first cover, 1G...second cover, 4...direction change mechanism (drive section), 5...selective valve, 6...solenoid valve, 7...throttle valve, 8...check valve, 9...first pressure gauge, 10...second pressure gauge, 11...filtrate on / off valve, 12...flow meter, 13...drainage throttle valve, 15...ventilation air supply valve, 20...raw solution tank, 21...solenoid valve, 22...solenoid valve, 23...second air supply valve, 24...third pressure gauge, 25...first air purge valve, 26...first air supply valve, 27...implantation air supply valve, 3 0...activated carbon slurry tank, 31...activated carbon impregnation valve, 40...cleaning tank, 41...third air supply valve, 42...second air purge valve, 43...fourth pressure gauge, 44...fourth air supply valve, 50...wastewater collection pail, 70...flat membrane, 71...fluid passage plate, 72...impregnated activated carbon, 73...raw solution, 81...piping, 82...piping, 83...piping, 84...piping, 85...piping, 86...piping, 87...piping, 88...piping, 100...flat membrane testing apparatus, 101...main section, 101A...activated carbon supply section, 101C...cleaning solution supply section, 101S...raw solution supply section, 102...control section, 103...measuring section, 104...recording section.

Claims

1. A flat membrane testing device that performs dead-end filtration using a flat membrane and cleaning of the flat membrane after filtration. a filtration section having a membrane mounting section to which a flat membrane is attached, a cleaning liquid jetting port provided to spray a cleaning liquid onto the raw liquid side surface of the flat membrane attached to the membrane mounting section, a liquid passage pipe extending from the cleaning liquid jetting port to the membrane mounting section along the spraying direction of the cleaning liquid so as to pass the cleaning liquid, a supply / discharge port provided on a side wall of the liquid passage pipe between the cleaning liquid jetting port and the membrane mounting section for supplying the raw liquid and discharging the cleaning liquid, and a filtrate discharge port communicating with the filtrate side of the flat membrane attached to the membrane mounting section; an orientation change mechanism that changes the orientation of the filtration unit between a filtration state in which the cleaning liquid jetting port is located at an upper position and the liquid passage pipe is oriented vertically and a cleaning state in which the supply / discharge port is located at a lower position and the liquid passage pipe is oriented horizontally; a raw liquid supply unit that supplies raw liquid to the supply / discharge port; a cleaning liquid supply unit that supplies cleaning liquid to the cleaning liquid jetting port; Equipped with A flat membrane testing device characterized by:

2. the orientation change mechanism is a drive unit that changes the orientation of the filtration unit by power, a measuring unit that automatically measures at least one of a filtration flow rate and a filtration differential pressure; a control unit that, when detecting that the measurement value of the measuring unit has reached a predetermined value, stops the raw liquid supply unit, drives the drive unit to change the orientation of the filtration unit from the filtration state to the cleaning state, and then starts the cleaning liquid supply unit; The flat membrane testing device according to claim 1, further comprising:

3. An activated carbon supply unit is provided which supplies activated carbon slurry to the supply and discharge port. The flat membrane testing device according to claim 1 or 2.

4. A flat membrane testing method for performing dead-end filtration using a flat membrane and cleaning the flat membrane after filtration, a membrane mounting part to which a flat membrane is attached; a cleaning liquid jetting port provided to spray a cleaning liquid onto the raw liquid side surface of the flat membrane attached to the membrane mounting part; a liquid passage pipe extending from the cleaning liquid jetting port to the membrane mounting part along the direction of spraying of the cleaning liquid so as to pass the cleaning liquid; a supply / discharge port provided in the side wall of the liquid passage pipe between the cleaning liquid jetting port and the membrane mounting part for supplying the raw liquid and discharging the cleaning liquid; and a filtrate discharge port communicating with the filtrate side of the flat membrane attached to the membrane mounting part, A membrane mounting step of mounting a flat membrane to the membrane mounting portion; a filtration step in which the filtration unit is placed in a filtering state in which the cleaning liquid jetting port is positioned at an upper position and the liquid passage pipe is oriented vertically, a raw liquid is supplied from the supply / discharge port by a raw liquid supply unit, and total filtration is performed by the flat membrane, and the filtrate is discharged from the filtrate discharge port; a cleaning step in which, after the filtration step, the supply and discharge port is positioned downward and the liquid passage pipe is oriented horizontally, and a cleaning liquid is sprayed from the cleaning liquid jet port onto the raw liquid side surface of the flat membrane to clean the flat membrane, and the cleaning liquid is discharged from the supply and discharge port; A flat membrane test method comprising:

5. After the membrane attachment step and before the filtration step, an activated carbon impregnation step in which the filtration unit is positioned so that the cleaning liquid injection port is positioned upward and the liquid passage pipe is oriented vertically, activated carbon slurry is supplied to the supply / discharge port to perform full filtration by the flat membrane, activated carbon is impregnated onto the surface of the flat membrane attached to the membrane attachment unit facing the cleaning liquid injection port, and the filtrate is discharged from the filtrate discharge port; The flat membrane testing method according to claim 4, comprising:

6. In the cleaning step, the cleaning liquid contains cleaning powder and granules. The flat membrane testing method according to claim 4 or 5.

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