JP2005161178A - Membrane filtering apparatus and its operating method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cross-flowing type membrane filtering apparatus permitting effective utilization of the energy of bubbles. <P>SOLUTION: Two filtering membrane modules 10a and 10b having tubular membrane units 11a and 11b, or filtering membrane units consisting of a group of filtering membranes housed in a housing container and filtering a to-be-treated liquid to give a filtrate, and bubble-supplying devices 12a and 12b supplying the bubbles toward the groups of the membranes are connected at both the upper and the lower ends to form connected portions. A bubble relief outlet 17 is arranged at the upper-end connected portion 15, and an inlet and outlet 16 for the liquid to be treated is disposed at the lower-end connected portion 14. the liquid to be treated is circulated by supplying bubbles alternately from the devices 12a and 12b to the groups of the membranes so as to yield a filtrate. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a membrane filtration device used for aeration and crossflow filtration using the buoyancy of bubbles in the field of ultrafiltration or microfiltration. More specifically, the present invention relates to two membrane membrane modules. The present invention relates to a membrane filtration apparatus that performs membrane filtration by connecting bubbles between upper ends and lower ends and alternately supplying bubbles to each filtration membrane module, and efficiently using the energy of bubbles.

  As the aeration / cross flow filtration, one using a tubular membrane element or one using a flat membrane element is known.

JP-A-9-99223

  Patent Document 1 discloses an aeration cross flow using a tubular membrane module in which a large number of tubular membranes are focused and fixed at both ends of an outer cylinder having an outlet for filtrate.

Japanese Patent Publication No. 4-70958

  Patent Document 2 discloses an aeration / crossflow filtration apparatus using a plurality of flat membrane modules.

  In the above-mentioned Non-Patent Document 1 and Patent Documents 1 and 2, an apparatus for supplying bubbles is arranged below a membrane separation unit comprising a tubular membrane, a tubular membrane module or a flat membrane module. On the other hand, a water tank for supplying the liquid to be treated is separately installed. That is, the liquid to be treated is configured to return to the water tank again after rising in the membrane separation unit as the bubbles rise. Therefore, in these apparatuses, when the number of membrane separation units increases, the number of water tanks must be increased. Therefore, there is a problem that the structure becomes complicated and the merit of scale cannot be expected. In addition, as the liquid to be treated returns to the water tank, bubbles in the liquid to be treated are released into the atmosphere, so that energy is used in one membrane separation unit, and there is a problem that energy is not used effectively. It was.

  The present invention can solve the above-mentioned problems, the structure does not become complex even when the number of membrane separation units is increased and the size is increased, and the flow energy of the gas-liquid mixed flow in aeration and crossflow filtration is effectively used. In order to obtain a membrane filtration device capable of effectively utilizing energy given to bubbles, a filtration membrane unit in which a filtration membrane group for obtaining a filtrate by filtering a liquid to be treated is stored in a storage container and the filtration Two filtration membrane modules each having a bubble supply device for supplying bubbles toward the membrane group are connected to each other at the upper end and the lower end to form a connecting portion, and the upper end connecting portion is degassed, It is a membrane filtration apparatus which provides a to-be-processed liquid inlet / outlet in a connection part (Claim 1). Further, the liquid inlet / outlet is connected to an adjustment tower for setting the water level of the liquid to be processed, and the liquid is alternately supplied from the bubble supply device of each filtration membrane module to the filtration membrane group. The liquid is set to obtain a filtrate while circulating the liquid while maintaining the water level (Claim 2). In addition, each of the filtration membrane modules is one in which the fractionation molecular weight or the fractional particle size of each filtration membrane group is different (Claim 3). The filtration membrane group includes a plurality of tubular membrane elements having a function of filtering the liquid to be treated on the inner surface, and is held at both upper and lower ends thereof and stored in a storage container. . Further, the tubular membrane element has a liquid permeability for imparting shape retention to the filtration membrane layer, which is disposed on the outer circumferential surface of the filtration membrane layer and the filtration membrane layer formed in a cylindrical shape. A support membrane layer is provided, and protrusions having an inner diameter of 2 to 15 mm and a height of 0.02 to 0.2 mm are partially formed on the outer peripheral surface. The support film layer is formed using a polypropylene or polyester resin nonwoven fabric. Moreover, the said filtration membrane layer consists of a microfiltration membrane or an ultrafiltration membrane (Claim 7). The filtration membrane group includes a plurality of flat membrane elements each having a flat membrane disposed on both surfaces of a rectangular flat membrane support plate having a filtrate flow passage so as to have a filtration function of the liquid to be treated. The sheet is included and held at both the left and right ends so that the interval is 2 to 10 mm and is stored in a storage container (claim 8). In addition, the flat membrane element includes a filtration membrane layer and a flat membrane membrane disposed on the inner surface of the filtration membrane layer and having a liquid permeability for imparting shape retention to the filtration membrane layer. The membrane is disposed on both surfaces of the membrane support plate (claim 9). Moreover, the said support film layer is formed using the nonwoven fabric of a polypropylene or polyester resin type | system | group (Claim 10). The filtration membrane layer is made of a microfiltration membrane or an ultrafiltration membrane. A filtration membrane module comprising a filtration membrane unit in which a filtration membrane group for filtering a liquid to be treated to obtain a filtrate is accommodated in a storage container, and a bubble supply device for supplying bubbles to the filtration membrane group Are connected to each other at the upper end and the lower end to form a connecting portion, and the liquid to be processed is circulated through a membrane filtration apparatus in which bubbles are removed from the upper end connecting portion and a liquid inlet / outlet is provided at the lower end connecting portion. This is a method for operating a membrane filtration device in which particles having a diameter smaller than the minimum dimension of the passage are added to circulate the liquid to be treated.

  According to the membrane filtration apparatus of the said Claims 1-11, two filtration membrane modules are connected with upper ends and lower ends, an air bubble removal is provided in an upper end connection part, and a to-be-processed liquid inlet / outlet is provided in a lower end connection part Therefore, if air bubbles are generated by alternately supplying air to the bubble supply device for each filtration membrane module, when the gas-liquid mixed flow flows through one filtration membrane module, the other filtration membrane The liquid to be treated after the bubbles are discharged flows through the module, and such two kinds of flows are alternately repeated. Therefore, not only the energy given to the liquid to be treated by the bubbles is efficiently used, but also the water tank for returning the liquid to be treated is not used, so that the structure of the apparatus can be simplified. Moreover, according to the operation method of the membrane filtration apparatus of the said Claim 12, it can suppress that a cake layer or a concentration polarization layer is formed in a film surface.

  Thereby, in one filtration membrane module in which the gas-liquid mixed flow is flowing, it is considered that the cake layer or the concentration polarization layer formed on the membrane surface is scraped off by the rising bubbles. On the other hand, in the other filtration membrane module in which the liquid to be treated that does not contain bubbles flows, the effect of removing the cake layer or the concentration polarization layer on the membrane surface due to the bubbles cannot be expected, so when the cake layer or the concentration polarization layer becomes thicker Conceivable. Therefore, filtration of the liquid to be treated can be continued without forming a strong cake layer or concentration polarization layer on the film surface.

  The filtration membrane group in the filtration membrane module includes a filtration membrane unit (tubular membrane unit) in which a large number of tubular membrane elements are converged and held at both ends and stored in a storage container, or a rectangular flat plate provided with a flow path for filtrate. Any of the filtration membrane units (flat membrane units) in which a plurality of flat membrane elements having flat membranes arranged on both sides of a membrane support plate are accommodated in a storage container at equal intervals, and bubbles are formed below these filtration membrane units. A supply device is arranged to form a filtration membrane module (tubular membrane module or flat membrane module), and bubbles are supplied inside the tubular membrane element in the former and between adjacent flat membrane elements in the latter.

  FIG. 1 shows a membrane filtration device 1 in which a filtration membrane unit includes a plurality of tubular membrane elements as a filtration membrane group according to the first embodiment of the present invention, and (a) is a BB of (b). Sectional views of the parts are shown, and (b) shows a sectional view of the AA part of (a), but the present invention is not limited to these figures.

  As shown in FIG. 1 (b), the upper end of the filtration membrane unit indicated by 11a and the filtration membrane unit indicated by 11b (hereinafter referred to as tubular membrane units 11a and 11b) are connected by an upper end connecting portion 15. The lower ends are connected by a lower end connecting portion 14 via bubble supply devices 12a and 12b. The upper end connecting portion 15 is provided with a bubble vent 17 and the lower end connecting portion 14 is provided with a liquid inlet / outlet 16 to be treated. Become. That is, as shown in FIG. 1A, a plurality of tubular membrane modules 10a (shown in the upper part of the figure) and a plurality of tubular membrane modules 10b (shown in the lower part of the figure) are in the same row. Are connected in the vertical direction. Each of the tubular membrane modules 10a and 10b includes tubular membrane units 11a and 11b in which a plurality of tubular membrane elements 111 are accommodated in a storage container 112 as a filtration membrane group, and air bubbles are directed toward the tubular membrane element 111. In order to supply, bubble generators 13a and 12b with built-in bubble generators 13a and 13b are formed. Bubbles are alternately generated from the bubble generators 13a and 13b, and the inside of the tubular membrane units 11a and 11b. Air bubbles are alternately supplied to the tubular membrane element 111. The bubble vent 17 is open to the atmosphere, and the liquid inlet / outlet 16 is connected to the liquid supply line 2 via the valve 21 and connected to the drain line 4 via the valve 41. . The treatment liquid supply line 2 is connected to an adjustment tower 3 for setting the water level of the treatment liquid, and the water level L1 of the treatment liquid in the membrane filtration apparatus 1 is set to the water level L2 set by the adjustment tower 3. Is set so that the liquid to be processed does not flow out of the bubble vent 17. If the water levels L1 and L2 are set in this way and the liquid to be processed is supplied at a pressure that does not hinder the flow of the liquid to be processed due to the rising of the bubbles, the liquid inlet / outlet 16 has a valve structure. Even if there is no provision, the liquid to be treated is guided to the tubular membrane module that generates air bubbles and filtered by the tubular membrane element 111 in the module, and is passed through the valve 51 from the filtrate outlets 115a and 115b. Thus, the filtrate can be taken out to the filtrate line 5.

  The above filtering operation will be described in more detail. That is, when bubbles are supplied to the tubular membrane unit 11b, the liquid to be processed rises with the bubbles in the tubular membrane unit 11b, descends through the upper end connecting portion 15, and further falls into the tubular membrane module 10a, and further, the lower end connecting portion. When the bubbles are supplied to the tubular membrane unit 11a again and circulate through the tubular membrane module 10b via 14, the liquid to be treated rises together with the bubbles in the tubular membrane unit 11 a and passes through the upper end connecting portion 15 to form a tubular shape. The inside of the membrane module 10b descends, and further operates to return to the tubular membrane module 10a through the lower end connecting portion 14 and circulate again, and these circulations are repeated alternately. In this way, while the liquid to be treated is circulating, the removal of the cake layer on the membrane surface is promoted by the tubular membrane module on the side where the bubbles are supplied. Further, the filtrate filtered through the tubular membrane modules 10a and 10b by suction pressure or siphon action is collected in the filtrate line 5 with the valve 51 opened, and the concentrated liquid to be treated is appropriately selected by the valve 21. Then, after closing the valve 51, the valve 41 is opened and discharged from the drainage line 4. In such a membrane filtration device 1, it is necessary to prevent pressure loss from occurring in the liquid to be circulated in the upper end connecting portion 15 and the lower end connecting portion 14 by providing resistance to the cross flow generated by the rising of the bubbles. is there. Normally, if the upper end connecting part 15 and the lower end connecting part 14 are designed so that the pressure loss is about 1 kPa or less, the operation of the membrane filtration device 1 can be performed smoothly.

  That is, as shown in FIG. 1A, in such a membrane separation apparatus 1, a plurality of sets of two tubular membrane modules are arranged, and a filtrate line 5 is disposed between each tubular membrane module. If the drainage line 4 is disposed at the upper end (upper part of the figure) and the liquid supply line 2 to be treated is disposed at the lower end (lower part of the figure) of each tubular membrane module, Even if a work space for replacement or the like is provided, the filtrate line 5, the discharge line 4 and the liquid supply line 2 to be processed can be shared among a pair of tubular membrane modules. Further, when such a membrane separation device 1 is further increased in size, it is only necessary to increase the number of sets of tubular membrane modules, so that a flexible response is possible. FIG. 1 shows only a part for easy understanding.

  FIG. 2 shows a tubular membrane unit 11 used in the membrane filtration device. That is, the tubular membrane unit 11 includes a cylindrical storage container 112 having a filtrate outlet 115, and a filtration membrane group composed of a number of tubular membrane elements 111 filled in the storage container 112. The container 112 and the filtration membrane group are focused and fixed at both ends by a potting material 113. Note that a wedge-shaped ring 114 is formed in the fixing portion so as to be buried in the potting material 113 so as to secure a passage for the filtrate and to prevent the potting material 113 and the storage container 112 from peeling off. Further, flanges 116 for facilitating the attachment and detachment of the tubular membrane unit 11 are provided at both ends of the storage container 112.

  In the tubular membrane element 111 described above, a filtration membrane having an inner diameter of 2 to 15 mm and having an ultrafiltration or microfiltration function on the inner surface is used so that the liquid to be treated flows without any stagnation as the bubbles rise. . The reason is that when the inner diameter is less than 2 mm, the tubular membrane element is likely to be blocked by impurities in the liquid to be treated, and when the inner diameter exceeds 15 mm, the tubular membrane element that can be filled into the storage container 112 having a limited volume is used. It is because the filtration area per unit volume becomes small as the number decreases. As such a filtration membrane, a composite membrane made of an organic polymer in which a support membrane layer and a filtration membrane layer are integrally formed is particularly suitable. The ultrafiltration membrane used as the filtration membrane layer refers to a membrane suitable for separating a 1 to 10 nm polymer material, and the microfiltration membrane includes fine particles and microorganisms of about 0.01 to several μm. A membrane suitable for separation (JIS K 3802). The support membrane layer is made of polypropylene or polyester nonwoven fabric for reasons such as waist strength, strength, chemical resistance, heat resistance and economy. Such a tubular membrane element 111 can be manufactured by forming a filtration membrane layer on the inner surface of a tubular support membrane layer, but it is more productive to process a sheet-like composite membrane into a tube shape. In terms of For example, as described in Japanese Patent Publication No. 56-35483, a tape-shaped composite membrane is spirally wound around a mandrel that defines an inner diameter, and its longitudinal peripheral portions are overlapped with each other, and an overlapping portion is formed. By bonding with an adhesive or ultrasonic welding, a tubular film having an arbitrary diameter can be continuously produced. Further, with this manufacturing method, not only can a high-strength support membrane layer be used so that it can withstand backwashing, which will be described later, but a clearance is secured between adjacent tubular membranes to filter the liquid to be treated. In order to make the cake layer or concentration polarization layer generated on the film surface easy to peel off by reducing the resistance or causing turbulence in the liquid to be treated, the adhesive part is thickened and the outer surface of the tubular film is uneven. This can be realized by forming. Such irregularities are preferably 0.02 to 0.2 mm in order to have the above-described effects. The tubular membrane unit is manufactured by the same method as that for manufacturing a hollow fiber membrane unit. That is, after closing the ends of a number of tubular membranes with a heat seal or the like, it is attached to a predetermined position of the storage container and immersed in a mold containing a thermosetting resin such as urethane resin, silicon resin or epoxy resin, If the resin is left as it is until it hardens, the tubular film is converged and fixed to the storage container as a potting material, and then the tip of the storage container is cut off together with the potting material so that the tip of the tubular film is opened. To do.

  FIG. 3 shows the bubble supply device 12 used in the membrane filtration device. That is, as shown in FIG. 3A, the bubble supply device 12 has a guide cylinder 121 whose outer diameter is the same as the outer diameter of the storage container 112 of the tubular membrane unit. The flange 122 for connecting to the flange 116 of the storage container 112 is provided, and the bubble generating device 13 is incorporated. The bubble generating device 13 is drawn out of the guide cylinder 121, and an air inlet 134 is fixed to the guide cylinder 121 at one end with a U-shaped bolt 135 and the other end is closed with a cap 136. As shown in FIG. 3B, the bubble generating device 13 is a cross-sectional view taken along line C1-C1 of FIG. 3A, and FIG. 3C is a cross-sectional view taken along line C2-C2 of FIG. 134 has a main pipe 131 connected to 134, a nozzle 133 a connected to the main pipe 131, and 133 b connected to the main pipe 131 via a branch pipe 132, and is fed into the main pipe 131 from the air inlet 134. The air thus blown out is ejected as bubbles from the nozzles 133a and 133b into the liquid to be treated. The nozzles 133a and 133b are disposed in the guide cylinder 121 so as to have a planar arrangement as indicated by reference numeral 133 in FIG. That is, among the three one-dot chain lines A, B, and C shown in the figure, if the diameter of the guide cylinder 121 is 20 to 25 cm, the nozzle arrangement is surrounded by the one-dot chain circle A, and the diameter of the guide cylinder 121 is 25 to 25 cm. If the diameter of the guide tube 121 is 30 to 35 cm, the nozzle arrangement is surrounded by the dot-dash line circles A, B, and C. Good. Since the bubbles ejected from the nozzle 133 rise in the guide cylinder 121 while expanding the meandering range, the number of the nozzles 133 can be reduced as the length of the guide cylinder 121 increases. Considering a range in which the length is not too long and the number of nozzles 133 is not too large, the length is preferably about 30 cm.

  Usually, the same tubular membrane units 11 described above are combined, but tubular membranes having different fractional molecular weights or fractional particle diameters may be used. In this way, two types of filtrate can be obtained.

  FIG. 4 shows a membrane filtration device 100 in which a filtration membrane unit includes a plurality of flat membrane elements as a filtration membrane group according to the second embodiment of the present invention, (a) is a plan view, and (b) is a plan view. (A) shows a cross-sectional view of the DD section, and (c) shows a cross-sectional view of the EE section of (b), but the present invention is not limited to these drawings.

  As shown in FIG. 4A, the membrane filtration device 100 of this embodiment includes a filtration membrane module indicated by 1000a and a filtration membrane module indicated by 1000b (hereinafter referred to as flat membrane modules 1000a and 1000b). As shown in FIG. 4B, the flat membrane modules 1000a and 1000b are connected at the upper ends with an upper end connecting portion 1005 and with the lower ends connected at a lower end connecting portion 1004 via bubble supply devices 1002a and 1002b. ing. The upper end connecting portion 1005 is opened to remove bubbles, and the lower end connecting portion 1004 is provided with a liquid inlet / outlet 16 to be processed. As shown in FIG. 4C, the flat membrane units 1001a and 1001b each have a plurality of flat membrane elements 1010 accommodated in a storage container 1014 as a filtration membrane group, and the storage container 1014 has a flat membrane. A potting material 1013 for fixing the element 1010 at a predetermined interval or a frame body 1013 for easily attaching and detaching the flat membrane element 1010 is provided. This interval is preferably set to 2 to 10 mm so that the liquid to be processed flows without any stagnation as the bubbles rise. Further, as shown in FIG. 4 (c), the flat membrane element 1010 is provided with a flat membrane 1011 having a function of filtering the liquid to be treated on both surfaces of the membrane support plate 1012. The membrane support plate 1012 is preferably made of a relatively inexpensive and rigid synthetic resin such as polyvinyl chloride or polypropylene. Further, the bubble supply devices 1002a and 1002b incorporate bubble generation devices 1003a and 1003b for supplying bubbles toward the flat membrane element 1010, and the bubble generation devices 1003a and 1003b alternately supply bubbles. Are generated so that air bubbles are alternately supplied to the flat membrane elements 1010 in the flat membrane units 1001a and 1001b. In FIG. 4, activated carbon may be mixed in the liquid to be treated. In this case, a deactivated activated carbon take-out line 7 and a valve 71 are preferably provided.

  The filtrate filtered by the flat membrane element 1010 is collected in the filtrate water collecting part 1015 from the passage inside each membrane support plate 1012 and taken out to the filtrate line 5 through the filtrate outlet 1016 and the valve 51. In addition, about the to-be-processed liquid supply line 2 and the drainage line 4, since it is the same as that of the case of a tubular membrane module, description is abbreviate | omitted.

  Next, maintenance of the flat membrane module and the tubular membrane module according to each embodiment described above will be described.

  In the tubular membrane module of the first embodiment, backwashing is mainly performed. That is, as shown in FIG. 5, the backwashing line 8 is connected to the path from the filtrate outlets 115a and 115b to the filtrate line. In addition, illustration of the upper end connection part 15 is abbreviate | omitted in FIG. In the backwashing method, the valve of the liquid to be treated and the valve 51 of the filtrate line are closed to stop the supply and filtration of the liquid to be treated, and then the valve V1 connected to the high-pressure air is opened to open the element. The filtrate inside is made to flow backward to the liquid to be treated. Thereafter, the valve V1 is closed, the valve V2 is opened, high pressure air in the element is released, the supply of bubbles is stopped, the valve 41 of the drainage line 4 is opened, and backwashing liquid (backflow) The filtrate and the liquid to be treated are mixed and discharged). When the valve 41 is closed and the valve 21 is opened, the liquid to be treated is introduced again into the tubular membrane modules 10a and 10b. Next, the operation of the bubble supply device is restarted, and after confirming that the filtrate has passed through the valve V2, the valve V2 is closed, and when the valve 51 is opened, the original filtration state is restored. As described above, since the bubbles have an action of scraping off the cake layer or the concentration polarization layer, the supply of bubbles may be continued even during the backwashing. Such backwashing can be completed in a short time of less than 1 minute if the liquid to be treated is easily filtered, such as river water, and a large number of such as shown in FIG. In the case of the membrane filtration device 1 to which the tubular membrane module is connected, it is preferable to sequentially perform such backwashing operation at regular intervals. Moreover, it is good to replace the tubular membrane module which supplies a bubble whenever backwashing is performed.

  In the flat membrane module of the second embodiment, chemical cleaning is mainly performed. The reason is that a flat membrane module cannot withstand backwashing, so when a cake layer or a concentration polarization layer adheres to the membrane surface, it is washed with a chemical solution such as sodium hypochlorite, acid or alkali. That is, as shown in FIG. 4B, a chemical liquid line 6 and a valve 61 for chemical liquid cleaning are provided. These chemical solutions are gradually fed into the membrane element 1010 by closing the filtrate valve 51 and opening the valve 61.

  In each of the above embodiments, in order to suppress the growth of the cake layer or the concentration polarization layer, particles having an inner diameter smaller than the inner diameter of the tubular membrane are added to the liquid to be circulated between the two sets of membrane modules. Also good. By adding such particles, the growth of the cake layer or the concentration polarization layer is suppressed, and the filtration rate can be increased. Therefore, it can be easily applied to the present embodiment. That is, with reference to FIG. 1 (b), the particles described above are introduced from the bubble vent 17 to be mixed in the liquid to be processed and circulated between the membrane modules, and provided at the liquid inlet / outlet. It is made to collect | recover at the time of discharge | emission of a concentrate with the mesh screen 18, and it is made to circulate between each membrane module again with the to-be-processed liquid introduced. When such particles are added, if it is observed that the gas-liquid mixed flow layer on the membrane surface has become thicker, the filtration rate may decrease rapidly. To add. It should be noted that the provision of the mesh screen 18 at the liquid inlet / outlet is simple, and does not complicate the recovery device. The addition of such particles can also be applied to a membrane filtration device comprising a flat membrane module.

  According to the present invention, by supplying bubbles to one of the two sets of membrane modules, the other membrane module can also generate a cross flow, so that the energy of the bubbles can be used effectively and effectively. Not only is it possible to use ancillary equipment such as a water tank, but a simple and compact device can be realized, so that the industrial applicability is extremely large.

The membrane filtration apparatus using the tubular membrane module which concerns on the 1st Embodiment of this invention. A tubular membrane unit used in the membrane filtration device. A bubble supply device used in the membrane filtration device. The membrane filtration apparatus using the flat membrane module which concerns on the 2nd Embodiment of this invention. The figure which attached the backwashing apparatus to the membrane filtration apparatus using a tubular membrane module.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,100 Membrane filtration apparatus 10a, 10b Tubular membrane module 11, 11a, 11b Tubular membrane unit 12, 12a, 12b, 1002a, 1002b Bubble supply apparatus 13, 13a, 13b, 1003a, 1003b Bubble generation apparatus 14, 1004 Lower end connection part 15, 1005 Upper end connection part 16 Processed liquid inlet / outlet 17 Bubble removal 18 Mesh screen 2 Processed liquid supply line 3 Control tower 4 Drain line 5 Filtrate line 6 Backwash line 7 Deactivated activated carbon take-out line 8 Backwash line 21, 41 51, 61, 71, V1, V2 Valve 111 Tubular membrane element 112, 1014 Storage container 113 Potting material 114 Wedge-shaped ring 115 Filtrate outlet 116, 122 Flange 121 Guide tube 131 Trunk tube 132 Branch tubes 133a, 133b Nozzle 134 Air inlet 135 U-shaped Bol 136 caps 1000a, 1000b flat membrane module 1001a, 1001b flat membrane unit 1010 flat sheet membrane element 1011 filtration membrane 1012 the membrane support plate 1013 frame 1015 filtrate passageway 1016 filtrate outlet

Claims (12)

A filtration membrane module comprising a filtration membrane unit in which a filtration membrane group for filtering a liquid to be treated to obtain a filtrate is contained in a storage container, and a bubble supply device for supplying bubbles to the filtration membrane group, A membrane filtration apparatus in which two units are connected to each other at the upper ends and the lower ends to form a connecting portion, with bubbles removed at the upper connecting portion and a liquid inlet / outlet at the lower connecting portion. The liquid inlet / outlet is connected to an adjustment tower for setting the water level of the liquid to be processed, and the liquid to be processed is supplied by alternately supplying bubbles from the bubble supply device of each filtration membrane module to the filtration membrane group. 2. The membrane filtration device according to claim 1, wherein the membrane filtration device is set so as to obtain a filtrate while circulating the water level. The membrane filtration device according to claim 1 or 2, wherein each of the filtration membrane modules has different molecular weights or fractional particle sizes of the respective filtration membrane groups. The filtration membrane group includes a plurality of tubular membrane elements having a function of filtering the liquid to be treated on the inner surface, and is held at both upper and lower ends and stored in a storage container. The membrane filtration apparatus described. The tubular membrane element includes a filtration membrane layer formed in a cylindrical shape and a support membrane having liquid permeability disposed on the outer peripheral surface of the filtration membrane layer for imparting shape retention to the filtration membrane layer The membrane filtration device according to claim 4, further comprising a layer, wherein a protrusion having an inner diameter of 2 to 15 mm and a height of 0.02 to 0.2 mm is partially formed on the outer peripheral surface. The membrane filtration apparatus according to claim 5, wherein the support membrane layer is formed using a polypropylene or polyester resin nonwoven fabric. The membrane filtration device according to claim 5, wherein the filtration membrane layer is made of a microfiltration membrane or an ultrafiltration membrane. The filtration membrane group includes a plurality of flat membrane elements each having a flat membrane disposed on both surfaces of a rectangular flat membrane support plate having a filtrate flow passage so as to have a function of filtering the liquid to be treated. And the membrane filtration apparatus in any one of Claims 1-3 hold | maintained so that a space | interval may be set to 2-10 mm in the both ends of the right and left, and accommodated in the storage container. The flat membrane element includes a filtration membrane layer and a flat membrane provided on the inner surface of the filtration membrane layer and having a support membrane layer having liquid permeability for imparting shape retention to the filtration membrane layer. The membrane filtration apparatus according to claim 8, which is disposed on both surfaces of the membrane support plate. The membrane filtration device according to claim 9, wherein the support membrane layer is formed using a polypropylene or polyester resin nonwoven fabric. The membrane filtration device according to claim 9, wherein the filtration membrane layer is made of a microfiltration membrane or an ultrafiltration membrane. A filtration membrane module comprising a filtration membrane unit in which a filtration membrane group for filtering a liquid to be treated to obtain a filtrate is contained in a storage container, and a bubble supply device for supplying bubbles to the filtration membrane group, Two passages are connected to each other at the upper ends and the lower ends to form a connecting portion, a bubble removal is provided at the upper end connecting portion, and a liquid filtration port is provided at the lower end connecting portion. A method for operating a membrane filtration device, in which particles having a diameter smaller than the minimum dimension are added to circulate the liquid to be treated.

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