JP2005193075A - Filtration apparatus and filtering method using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To efficiently filter original water by effectively preventing a filtration membrane from being clogged by turbid matter etc. in the original water by surely forming an activated carbon membrane having uniform thickness on the filtration membrane when the original water introduced into a filtration module is filtered while adsorbing organic matter etc. in the original water by using activated carbon. <P>SOLUTION: This filtration apparatus is provided with: the filtration module 1 in the casing 1A of which the filtration membrane 2 is housed for filtering the original water W to obtain filtrate T; a filtrate discharging means 4 connected to the filtration module 1 for discharging the filtrate T and; an activated carbon-suspended suspension supplying means 8 for supplying an activated carbon C-suspended suspension E to the filtration module 1 in such a condition that the original water W is not introduced into the filtration module 1. A membrane or a layer of activated carbon C is formed on the filtration membrane 2 by filtering the suspension E by the filtration membrane 2 and then the original water is filtered by introducing the original water W into the filtration module 1. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a filtration device for filtering raw water in a water purification plant or the like, and a raw water filtration method using the filtration device.

As this type of filtration device and filtration method, for example, in Patent Documents 1 to 5, a filtration unit constituted by a filtration membrane such as a hollow fiber membrane is accommodated in a filtration tank into which raw water to be filtered is introduced. It has been proposed to be immersed in the raw water and provided with an air diffuser or the like for cleaning the filtration unit by diffusing air into the raw water in the filtration tank below the filtration unit. And in the filtration apparatus and the filtration method of these patent documents 1-5, activated carbon is added to the raw | natural water introduce | transduced in this filtration tank, or activated carbon is immersed or incorporated in a filtration tank, Filtering efficiency is improved by adsorbing organic substances in water with the activated carbon.
JP-A-8-57273 Japanese Patent Laid-Open No. 9-24250 Japanese Patent Laid-Open No. 10-323683 JP 2003-94056 A Japanese Patent No. 3440402

  By the way, when the activated carbon is supplied into the filtration tank into which the raw water is introduced and filtration is performed, in addition to the adsorption action of the organic matter etc. of the activated carbon itself, the activated carbon is hollow in the filtration unit during the filtration of the raw water. A membrane or layer of activated carbon (hereinafter simply referred to as activated carbon membrane) is formed by being adsorbed on the surface of a filtration membrane such as a yarn membrane, so that the turbidity in the raw water adheres directly to the surface of the filtration membrane. The effect of preventing clogging from occurring can be expected.

  However, in the filtration devices and filtration methods described in Patent Documents 1 to 4, activated carbon is added to the raw water itself before being introduced into the filtration tank, or raw water is introduced into the filtration tank containing the activated carbon. Therefore, before such an activated carbon membrane is formed on the surface of the filtration membrane, the turbidity in the raw water is adsorbed on the surface of the filtration membrane and cannot be blocked or clogged. There is a problem that an activated carbon film is not formed on the surface of the filtration membrane around the portion, or even if an activated carbon film is formed, the film thickness becomes non-uniform. Moreover, in the filtration apparatus and the filtration method of patent document 5, activated carbon is immersed in the outer side of the filtration unit immersed in the raw water in a filtration tank through the support material which consists of a casing of a filtration tank and a perforated plate. Therefore, the activated carbon membrane is not formed on the filtration membrane surface of the filtration unit. Moreover, all of them are immersion type filtration membranes, and are not casing type membrane modules in which a filtration membrane is set in a casing.

  The present invention has been made under such a background. When the raw water is filtered through the filtration membrane while adsorbing organic matter in the raw water using the activated carbon as described above, the activated carbon is applied to the filtration membrane. A filtration device capable of effectively preventing clogging of the filtration membrane due to turbidity or the like in raw water by forming the membrane with a reliable and uniform film thickness, and the filtration It aims at providing the filtration method using an apparatus.

  In order to solve the above-described problems and achieve such an object, the filtration device of the present invention is connected to a filtration module in which a filtration membrane is housed in a casing and filters filtrate from raw water, and the filtration module. The raw water introduction means for introducing the raw water, the filtered water discharge means for discharging filtered water connected to the filtration module, and the activated carbon suspended in the filtration module in a state where the raw water is not introduced into the filtration module. And an activated carbon suspension supply means for supplying the prepared suspension. Further, the filtration method of the present invention is a filtration method using such a filtration device, and in the state where the raw water is not introduced into the filtration module, the activated carbon suspension is supplied to the filtration module with activated carbon. The suspension is supplied with the suspension, and the suspension is filtered through the filtration membrane to form the activated carbon membrane or layer on the filtration membrane. Thereafter, the raw water is introduced into the filtration module. And filtering.

  In the filtration device and the filtration method configured as described above, the raw water is not introduced into the filtration module as described above, that is, the raw water is not yet introduced into the filtration module at the time of the first operation of the filtration device. In addition, after the previous raw water filtration operation is completed, the raw water is discharged from the filtration module and immediately before the raw water of the next filtration operation is introduced into the filtration module, and after the filtration membrane to be described later, from the filtration module In a state where the raw water is discharged, first, a suspension in which activated carbon is suspended in the filtration module is supplied by the activated carbon suspension supply means. The suspension is filtered through the filtration membrane, and the filtered water is filtered. By discharging by the water discharging means, only the activated carbon contained in the suspension is adsorbed to the filtration membrane, and the activated carbon membrane is formed.

  Therefore, the activated carbon membrane formed in this way is not formed by filtering raw water to which activated carbon is added, so that the filtration membrane is not clogged with turbidity in the raw water, In addition, the activated carbon membrane can be formed uniformly throughout the entire filtration membrane without the activated carbon membrane being partially formed or non-uniform in thickness due to the clogging. . Then, after such an activated carbon membrane is formed, raw water is introduced into the filtration module, and the filtration is performed using the filtration device having the above-described configuration. This activated carbon membrane prevents direct adsorption and clogging, and organic matter in raw water is adsorbed by the activated carbon itself, and only the fine turbidity that was not adsorbed by the activated carbon membrane or activated carbon itself is filtered by the membrane. Since filtration is performed, it is possible to reduce the burden on the filtration membrane and to perform efficient raw water filtration.

  In the filtration apparatus, the activated carbon suspension is supplied to the filtration module while being circulated between the activated carbon suspension supply means and the filtration module. In the filtration method, the suspension is circulated between the activated carbon suspension supply means and the filtration module while being filtered through the filtration membrane while being supplied to the filtration module. An activated carbon membrane having a uniform film thickness can be formed on the filtration membrane by making the activated carbon concentration of the suspension liquid uniform. In particular, when the suspension is circulated in this manner, the concentration of the activated carbon in the suspension is set to a low concentration in the range of 0.1 to 100 mg / l, so that it is more dense and qualitatively uniform. An activated carbon film can be formed. Furthermore, when forming the activated carbon membrane by filtering the suspension with the filtration membrane in this way, the filtration module is provided with a suction means connected to the filtration module to suck the filtrate. Even if the filtration device is a pressure filtration that performs filtration by the pressure of the raw water itself introduced into the active water film, the formation of the activated carbon membrane by filtration of the suspension can be performed by suction by this suction means, so It becomes possible to form an activated carbon film having a predetermined film thickness.

  On the other hand, after forming the activated carbon membrane on the filtration membrane in this way, by introducing the raw water into the filtration module and performing the filtration treatment, the turbidity in the raw water is adsorbed on the activated carbon membrane and the activated carbon, and the adsorption capacity decreases, Alternatively, when the raw water is filtered by the filtration membrane itself, turbidity adheres to the surface and the filtration efficiency is lowered. In the filtration device, the raw water is contained in the filtration module. In the filtration method, after the raw water is introduced into the filtration module and filtered, the raw water is still introduced into the filtration module. The filtration membrane is washed in a state, and then the raw water is discharged so that the raw water is not introduced into the filtration module. And the suspended solid adhering to the activated carbon layer and a filtration membrane peeling to remove from the filter membrane, can be discharged together with the raw water in the filtration module. Therefore, after discharging the raw water in this way, the activated carbon suspension is supplied again to the filtration module by the activated carbon suspension supply means and filtered through the filtration membrane, so that the filtration membrane does not contain turbidity in the raw water. Since the activated carbon membrane can be formed, the above-described efficient raw water filtration process can be resumed.

  1 to 3 show first to third embodiments of the filtration device of the present invention, and show a case where the present invention is applied to a filtration device including an external pressure type filtration module 1. . Among these, in the first embodiment shown in FIG. 1, the filtration module 1 is configured such that the filtration membrane 2 is accommodated in a bottomed cylindrical casing 1A extending in the vertical direction. In the present embodiment, as shown in a simplified manner in FIG. 1, the filtration membrane 2 is composed of a number of hollow fiber membranes 2 </ b> A that also extend in the longitudinal direction, and these hollow fiber membranes 2 </ b> A constitute the upper end of the filtration module 1. The inside of the hollow fiber membrane 2A is closed such that its lower end is joined to the bottom of the filtration module 1, and the upper end is the above-mentioned. The header portion 2B communicates with the header portion 2B.

  And in the filtration apparatus of this embodiment made into the external pressure type, the raw water W introduced into the filtration module 1 by the raw water introduction means 3 is around the hollow fiber membrane 2A of the filtration membrane 2 in the casing 1A of the filtration module 1 ( And is filtered by the hollow fiber membrane 2A by the pressure and soaks into the hollow fiber membrane 2A as filtered water T. The filtered water T passes from the header portion 2B through the filtered water discharge means 4 Discharged. In addition to the bundle of the hollow fiber membranes 2A, the filtration membrane 2 is formed by stacking a number of elements having a hollow fiber membrane stretched into a screen or a flat membrane-like separation membrane, or a tubular membrane. A plurality of ceramic membrane elements may be bundled and connected to the header portion.

  Here, the raw water W introduced into the filtration module 1 is filtered at a water purification plant, for example. In the raw water introduction means 3, the raw water W is temporarily held in the raw water tank 3A, and the valve V1 is supplied to the filtration module 1 through a feed water pipe 3B connected to the bottom side of the filtration module 1 at a pressure higher than the atmospheric pressure by a feed water pump 3C provided between the valve V1 and the raw water tank 3A. Has been introduced. A drain pipe 3D having a valve V2 is branched from between the filtration module 1 of the water supply pipe 3B and the valve V1.

  Further, a return pipe 3E provided with a valve V3 is connected to the upper side of the filtration module 1, and the raw water W introduced into the filtration module 1 is circulated to the raw water tank 3A. In the filtration device of the present embodiment, a flow of raw water W is formed in the filtration module 1 from the bottom to which the water supply pipe 3B is connected toward the upper side, and the hollow fiber membrane 2A of the filtration membrane 2 A cross-flow type filtration device that extends along the direction and filters the raw water W in a direction intersecting the direction from the surface thereof. An overflow pipe 3F having a valve V4 is further branched from between the filtration module 1 of the return pipe 3E and the valve V3.

  Furthermore, the header portion 2B of the filtration membrane 2 is connected to a discharge pipe 4A of the filtrate discharge means 4 for discharging the filtrate T filtered by the hollow fiber membrane 2A. Here, in the filtration device according to the present embodiment that adopts the pressure filtration method as described above, this filtered water discharge means 4 is supplied to the filtration module 1 by a feed water pump 3C of the raw water introduction means 3 at a pressure larger than atmospheric pressure. The filtered water T filtered from the introduced raw water W and flowing into the header part 2B from the hollow fiber membrane 2A is opened to the atmospheric pressure at the end opposite to the side connected to the header part 2B of the discharge pipe 4A. Thus, the filtered water T is discharged by a pressure difference.

  Further, a valve V5 is provided on the discharge pipe 4A of the filtered water discharge means 4, and a branch pipe 5A provided on both sides of the discharge pipe 4A sandwiching the valve V5 so as to straddle the valve V5. Are connected to each other, and a valve V6, a suction pump 5B, and a valve V7 are sequentially provided in the branch pipe 5A in the direction of discharging the filtrate T. The branch pipe 5A, the suction pump 5B, and the valves V6 and V7 constitute the suction means 5 provided in the filtered water discharge means 4 in the present embodiment.

  Furthermore, the discharge pipe 4A of the filtered water discharge means 4 is provided with a first cleaning means 6 as one of the cleaning means for cleaning the filtration membrane 2 in this embodiment. In the first cleaning means 6, a filtered water pipe 6A branched from the suction direction of the filtered water T with respect to the suction means 5 is connected to the filtered water tank 6B via a valve V8, and from the filtered water tank 6B. A backwash pipe 6D having a backwash pump 6C and a valve V9 is connected between the header portion 2B of the discharge pipe 4A and the branch pipe 5A of the suction means 5.

  On the other hand, a second cleaning means 7 is provided at the bottom of the filtration module 1 as another cleaning means. The second cleaning means 7 is connected to the bottom of the casing 1A of the filtration module 1 so that a large number of air diffusers 7A are opened at one end around the hollow fiber membrane 2A joined to the bottom of the casing 1A. At the same time, the other end of these air diffusers 7A is connected to a compressor 7B that supplies air to the air diffuser 7A via a valve V10. Further, above the return pipe 3E in the casing 1A of the filtration module 1, the air supplied into the casing 1A by the second cleaning means 7 or the air remaining in the casing 1A when the raw water W is introduced. An intake / exhaust pipe 1B for discharging air and introducing air into the casing 1A when the raw water W is discharged from the filtration module 1 is connected via a valve V11.

  Further, in the present embodiment, an activated carbon suspension supply means (hereinafter simply referred to as supply means) 8 for supplying a suspension E in which activated carbon C is suspended in the filtration module 1 is provided. The supply means 8 is connected to the filtration module 1 in a state where the raw water W is not introduced into the filtration module 1 and supplies the suspension E. That is, the supply means 8 in this embodiment includes a suspension tank 8A that holds the suspension E in which the activated carbon C is suspended in clear water such as the filtered water T, and the suspension. The liquid tank 8A is provided with a liquid supply pipe 8C connected to the bottom side of the casing 1A of the filtration module 1 through the supply pump 8B and the valve V12, and the raw water W is introduced by the operation of the valve V12. In this embodiment, the suspension E is controlled so that the suspension E can be supplied into the casing 1A.

  Furthermore, the supply means 8 of this embodiment includes a return pipe 8D that circulates the suspension E supplied into the filtration module 1 to the suspension tank 8A. The return pipe 8D is connected to a position lower than the intake and exhaust pipe 1B in the upper part of the casing 1A of the filtration module 1 via a valve V13. In this embodiment, the valve V13 is operated together with the valve V13. The suspension E circulates between the suspension tank 8A and the filtration module 1 through the return pipe 8D and the liquid supply pipe 8C connected to the bottom side of the filtration module 1 while passing through the filtration module 1. It is made to be supplied.

  The activated carbon C suspended in the suspension E preferably has an average particle size of about 10 to 200 μm, and the activated carbon concentration in the suspension E supplied to the filtration module 1 is determined in this embodiment. The concentration is as low as about 0.1 to 100 mg / l. Furthermore, the suspension tank 8A is provided with a stirring device 8E that stirs the supplied filtered water T and the like, the activated carbon C and the suspension E returned from the filtration module 1, and thus the suspended suspension thus stirred. The supply amount of the filtered water T and the activated carbon C supplied to the suspension tank 8A is set so that the activated carbon concentration of the suspension E in the suspension tank 8A is substantially constant in the above range. Adjusted.

  Next, with respect to the first embodiment of the filtration method of the present invention using the filtration device of the first embodiment, the filtration membrane 2 is washed after the normal raw water W filtration operation, and then the filtration membrane 2 An explanation will be given of the case where the membrane of the activated carbon C is formed on the surface of the hollow fiber membrane 2A and then the normal raw water W is filtered again. In this embodiment, at the time of normal raw water W filtration operation, the valves V1, V3, V5, and V11 are opened and the remaining valves V2, V4, V6 to V10, V12, and V13 are closed, and the raw water in the raw water tank 3A. W is supplied and introduced into the casing 1A from the bottom side of the filtration module 1 through the feed pipe 3B by the feed water pump 3C, and is further circulated from the upper part of the filtration module 1 to the raw water tank 3A through the return pipe 3E. Note that after the raw water W is filled in the casing 1A, the valve V11 is closed.

  The raw water W thus introduced into the casing 1A of the filtration module 1 and filled outside the filtration membrane 2 is pressurized and filtered by the pressure of the raw water W through the filtration membrane 2 as described above. The filtered water T oozes into the hollow fiber membrane 2A, and the filtered water T thus filtered is discharged from the header portion 2B through the discharge pipe 4A of the filtrate discharge means 4. Further, a part of the discharged filtered water T is introduced and held from the filtered water pipe 6A to the filtered water tank 6B by opening the valve V8. In addition, the surface (outer peripheral surface) of the hollow fiber membrane 2A of the filtration membrane 2 during the filtration operation is already covered with the activated carbon membrane of the activated carbon C formed before the raw water W is introduced during the filtration operation. It shall be.

  While the raw water W is filtered in this way, the activated carbon C, the individual activated carbon C itself, or the turbidity in the raw water W adheres to and adsorbs to the hollow fiber membrane 2A. In the present embodiment, when the filtration capacity of the filtration membrane 2 is reduced or the filtration resistance is increased, in the present embodiment, the raw water W is introduced into the filtration module 1, and the first and second cleaning means 6, 7 is used to wash the filtration membrane 2, and then the raw water W is discharged from the filtration module 1. In other words, in the filtration method of the present embodiment, the filtration membrane 2 is washed before the raw water W is discharged from the filtration module 1.

  That is, during the cleaning operation of the filtration membrane 2, the valves V2, V6, V7, V12, and V13 are first closed, and the valves V1 and V3 that were open during the filtration operation are closed to introduce the raw water W into the filtration module 1 and The circulation from the filtration module 1 to the raw water tank 3A is stopped, the valve V5 is also closed and the discharge of the filtrate water T is also stopped, and then the valves V4 and V11 are opened and the intake / exhaust pipe 1B connected to the upper part of the filtration module 1 and the overflow Open tube 3F. Thereafter, in the first cleaning means 6, the valve V9 is opened and the backwash pump 6C is driven, and the hollow fiber membrane is passed from the filtrate water tank 6B through the backwash pipe 6D, the discharge pipe 4A, and the header portion 2B. By supplying backwash water such as filtered water T into the interior of 2A, the backwash water is jetted from the hollow fiber membrane 2A into the raw water W in the casing 1A, and the activated carbon membrane is peeled off together with the suspended matter. At the same time, turbidity adhering to the hollow fiber membrane 2A itself is also peeled off.

  Further, in the second cleaning means 7, the valve V10 is opened and the compressor 7B is driven so that air bubbles are ejected from the diffuser pipe 7A into the raw water W in the casing 1A of the filtration module 1 by air scrubbing. The activated carbon membrane is peeled off, and the turbidity on the surface of the hollow fiber membrane 2A is also peeled off. The air thus blown into the raw water W is exhausted from the intake / exhaust pipe 1B, and the raw water W overflowed from the casing 1A due to the injection of the air and the backwash water is accompanied by the separated turbidity and activated carbon C. The suspended waste water D is discharged from the overflow pipe 3F. Further, after the filtration membrane 2 is washed by the first and second washing means 6 and 7, the valves V9 and V10 are closed, the backwash pump 6C and the compressor 7B are stopped, and then the valve V11 is opened. By opening the valve V2 as it is, the turbidity and activated carbon C from which the raw water W in the filtration module 1 has been peeled are discharged as turbid wastewater D from the bottom of the casing 1A through the drain pipe 3D.

  And in the filtration method of this embodiment, after the raw | natural water W is discharged | emitted from the inside of the filtration module 1 in this way, it is filtered by the said supply means 8 in the state where the raw | natural water W filtered next is not introduced into the filtration module 1. Suspension E is supplied to the module 1, and an activated carbon membrane is formed on the hollow fiber membrane 2 </ b> A in the filtration membrane 2 by the activated carbon C suspended in the suspension E. That is, during the supply operation of the suspension E, first, the valve V2, V4 is closed, and the valve V12 is opened with the valves V1, V3, V5 to V10 closed, and the suspension E in the suspension tank 8A is opened. Is supplied from the bottom into the casing 1A of the filtration module 1 through the supply pipe 8C by the supply pump 8B. Further, in the present embodiment, the valve V13 is opened together with the valve V12, and the suspension E supplied into the filtration module 1 is circulated from the upper part of the casing 1A to the suspension tank 8A via the return pipe 8D. Between the suspension tank 8A of the supply means 8 and the filtration module 1, the suspension E adjusted to have a certain relatively low activated carbon concentration as described above is circulated.

  Further, when the suspension E circulates and is supplied to the filtration module 1 in this way, the suspension E is filtered by the filtration membrane 2 after the valve V11 is closed, Activated carbon C in the suspension E is adsorbed on the surface of the hollow fiber membrane 2A of the filtration membrane 2 to form an activated carbon membrane. However, at this time, the filtered water T filtered from the suspension E is discharged through the discharge pipe 4A by the filtered water discharge means 4, but in this embodiment, the filtered water of the suspension E is filtered. Instead of using the filtered water discharge means 4 that discharges the filtered water T that has been pressure-filtered from the raw water W during the normal raw water W filtration operation, the T is provided in the filtered water discharge means 4. The suction means 5 is used to suck the filtrate T from the filtration membrane 2 while the suspension E is supplied to the filtration module 1.

  That is, when the filtered water T is discharged by filtering the suspension E, the branch pipe 5A of the suction means 5 branched from the discharge pipe 4A with the valve V5 in the discharge pipe 4A of the filtered water discharge means 4 closed. The suction means 5 is connected to the filtration membrane 2 by opening the valves V6 and V7, and the suction pump 5B is driven. Therefore, the suspension E supplied to the filtration module 1 does not depend only on the pressure of the suspension E itself by the supply pump 8B, but the filtered water T from the hollow fiber membrane 2A of the filtration membrane 2 by the suction means 5. Is filtered as it is sucked and discharged, whereby the activated carbon C in the suspension E is adsorbed and an activated carbon membrane is formed on the surface of the hollow fiber membrane 2A as described above.

  Thus, when an activated carbon membrane having a predetermined film thickness is formed on the surface of the hollow fiber membrane 2A of the filtration membrane 2 in this way, the valves V12 and V13 of the supply means 8 are closed and the supply pump 8B is stopped to suspend the suspension. The supply and circulation of E are finished, the valves V6 and V7 of the suction means 5 are closed, the suction pump 5B is stopped, and the suction of the filtered water T and the filtration of the suspension E by the suction means 5 are also finished. The raw water W is introduced into the filtration module 1 to resume the normal filtration operation described above. That is, the valves V1 and V3 are opened and the feed water pump 3C is driven to introduce the raw water W from the raw water tank 3A into the filtration module 1 and circulate from the return pipe 3E, and the valve V5 of the filtered water discharge means 4 is opened. The filtered water T filtered from the raw water W by the filter membrane 2 is discharged through the discharge pipe 4A.

  In the filtration device configured as described above and the raw water W filtration method using the filtration device, the activated carbon membrane formed on the filtration membrane 2 is in a state where the raw water W is not introduced into the filtration module 1. 1 is formed by supplying a suspension E in which activated carbon C is suspended in 1. Before the activated carbon C is adsorbed by the hollow fiber membrane 2A to form the activated carbon membrane, Preventing the occurrence of turbidity and the like from adhering to the surface of the hollow fiber membrane 2A, and forming a membrane or layer of only the activated carbon C supplied as the suspension E on the hollow fiber membrane 2A. Can do. For this reason, turbidity or the like first adheres to the hollow fiber membrane 2A and becomes clogged, so that the activated carbon C is not adsorbed around it and the activated carbon membrane is not partially formed. Even if an activated carbon membrane is formed, the thickness of the membrane does not become partially uneven, and the thickness of the filtration membrane 2 is surely and evenly uniform. It becomes possible to form an activated carbon film.

  Therefore, according to the filtration apparatus and the filtration method having the above-described configuration, by filtering the raw water W by the filtration membrane 2 in which the activated carbon membrane having a uniform thickness as a whole is uniformly formed on the hollow fiber membrane 2A, Relatively large turbidity in the raw water W can be reliably captured by the activated carbon membrane, and the turbidity adheres directly to the surface of the hollow fiber membrane 2A, causing clogging and the like in the hollow fiber membrane 2A. It can prevent that filtration is inhibited. And the organic matter etc. in raw water W smaller than the turbidity captured by this activated carbon membrane are adsorbed by activated carbon C itself forming the activated carbon membrane, and only the fine turbidity smaller than this organic matter etc. is absorbed by the hollow fiber membrane 2A. Since the raw water W is captured and filtered and discharged as filtered water T, it is possible to reduce the burden on the filtration membrane 2 and to efficiently filter the raw water W.

  In the present embodiment, the supply means 8 includes a return pipe 8D, and the suspension E is circulated between the suspension tank 8A and the filtration module 1 while being supplied to the filtration module 1. By filtering with the membrane 2, the activated carbon membrane is formed on the hollow fiber membrane 2A. Therefore, when the supply amount of the activated carbon C supplied to the suspension tank 8A is set, only the filtered water T is supplied to the suspension tank 8A upon completion of the filtration operation after the supply of the activated carbon C is completed. Liquid E becomes clear. When the suspension E supplied to the filtration module 1 is clarified, the set amount of activated carbon is all supplied to the membrane surface of the filtration module 1, and quantitative activated carbon can be supplied. In addition, in the filtration module 1, as in the flow of the raw water W in the present embodiment, the suspension is directed from the bottom of the filtration module 1 to which the supply pipe 8C is connected to the upper part of the filtration module 1 to which the return pipe 8D is connected. Since the flow of E is formed, the concentration of the activated carbon in the suspension E can be made uniform. By forming the suspension E by filtration, the activated carbon membrane The film thickness can be made more uniform and constant. For this reason, according to this embodiment, it is possible to capture large turbidity by the activated carbon membrane that is uniform and uniform throughout the entire filtration membrane 2, adsorption of organic matter, etc., and capture of fine turbidity by the hollow fiber membrane 2A. Thus, more efficient filtration can be promoted.

  In the present embodiment, the activated carbon concentration of the suspension E supplied to the filtration module 1 is set to a low concentration of 0.1 to 100 mg / l. Therefore, when the suspension E is filtered, The activated carbon membrane is formed on the hollow fiber membrane 2A so as to gradually increase the film thickness. Therefore, contrary to this, it is possible to prevent the activated carbon film from being rapidly formed as in the case of supplying the high-concentration suspension E, thereby preventing variations in the density of the activated carbon C in the film. Since it becomes possible to form a more dense and qualitatively uniform activated carbon membrane, according to the present embodiment, such an activated carbon membrane is uniformly formed on the entire filtration membrane 2, thereby further uniforming the activated carbon membrane. It becomes possible to capture turbidity in raw water W and adsorb organic substances.

  In addition, since the suspension E has a low activated carbon concentration in this way, even if the suspension E is filtered together with the raw water W or recirculated to the raw water tank 3A via the return pipe 3E, the raw water W may be filtered. When the raw water W is introduced and filtered after the activated carbon membrane is formed on the hollow fiber membrane 2A, the suspension E remaining in the filtration module 1 is discharged through the drain tube 3D. Even if it does not do, it will become possible to introduce the raw water W into the filtration module 1 as it is, and to perform the filtration. For this reason, after the activated carbon membrane is formed in this way, by introducing the raw water W into the filtration module 1 without discharging the suspension E from the filtration module 1, the time and labor required for discharging the suspension E can be reduced. There is also an effect that it is possible to save the efficiency of the filtering work. Needless to say, if the activated carbon concentration of the suspension E exceeds the above range, these effects may not be obtained, but conversely, the activated carbon concentration of the suspension E decreases as it falls below the above range. If it is too much, it takes a long time to form an activated carbon film having a predetermined film thickness, and on the contrary, the operation efficiency of the filtration device may be reduced.

  Furthermore, the size of the activated carbon C suspended in the suspension E is also made finer with an average particle size of about 10 to 200 μm, so that the activated carbon membrane formed on the hollow fiber membrane 2A can be made more dense. The variation in density can be made small, and the turbidity in the raw water W can be captured more reliably and uniformly in the entire filtration membrane 2. That is, when the average particle size of the activated carbon C is larger than the above range, a gap formed between adjacent activated carbons C in the formed activated carbon film is increased, and a relatively large turbidity is present in the gap. There is a possibility of passing through and adhering to the hollow fiber membrane 2A, and also the variation in particle size of individual activated carbon C may be increased, resulting in partial coarseness of the activated carbon membrane. However, if the activated carbon C is too fine so that the average particle size is below the above range, the gap between the activated carbons C becomes too small, and the resistance when the raw water W to be filtered passes through the activated carbon membrane increases. Since there is a possibility that the filtration resistance is increased excessively, it is desirable that the average particle diameter of the activated carbon C is in the range of 10 to 200 μm as described above.

  Furthermore, when such a suspension E is filtered through the filtration membrane 2 to form an activated carbon membrane on the hollow fiber membrane 2, in this embodiment, the suction means 5 provided in the filtrate discharge means 4 is used. The activated carbon membrane is formed on the hollow fiber membrane 2A by sucking the filtered water T from the raw water W through the hollow fiber membrane 2A and filtering it with the suction pump 5B. However, when the activated carbon membrane is formed by filtering the suspension E, the filtered water T is leached out by the pressure of the suspension E supplied to the filtration module 1 in the same manner as when the raw water W is filtered. It is possible to form the activated carbon membrane by attaching the activated carbon C to the hollow fiber membrane 2A by performing filtration while discharging it from the discharge pipe 4A of the filtered water discharging means 4, but such pressure filtration In the system, there is a possibility that the film thickness of the activated carbon film becomes thinner on the upper side compared with the vicinity of the bottom of the filtration module 1 having a high pressure, whereas in the present embodiment, the activated carbon is activated by the suction means 5. Since the activated carbon membrane is formed by adsorbing C to the hollow fiber membrane 2A, it is possible to suppress the non-uniformity of the film thickness due to such a pressure difference, and it is possible to form an even more uniform activated carbon membrane. It becomes.

  Moreover, in the filtration device of the present embodiment, the suspension E is supplied from the bottom side of the filtration module 1, whereas the suction means 5 is operated by operating the valves V5 to V7 during the supply. Connected to the portion 2B, the filtered water T is sucked from the upper side of the filtration module 1 through the hollow fiber membrane 2A. Therefore, the activated carbon C can be adsorbed with a strong suction force on the upper side of the filtration module 1 where the supply pressure of the suspension E from the liquid supply pipe 8C of the supply means 8 connected to the bottom side of the filtration module 1 is weakened. On the other hand, on the bottom side of the filtration module 1 where the suction force is weakened, the activated carbon C can be reliably attached to the hollow fiber membrane 2A by the supply pressure of the suspension E. There is also an advantage that the non-uniformity can be more reliably suppressed, and the activated carbon membrane can be made more uniform over the entire filtration membrane 2.

  On the other hand, the filtration device of the present embodiment includes first and second cleaning means 6 and 7 for cleaning the filtration membrane 2 in a state where the raw water W is introduced into the filtration module 1. In this filtration method, when the raw water W is filtered and the filtration resistance increases or the adsorption capacity decreases due to suspended turbidity or organic matter adhering to and adsorbing to the activated carbon membrane or the hollow fiber membrane 2A, the cleaning means 6 , 7 and then the raw water W remaining in the filtration module 1 is discharged so that the source water W before the suspension E is supplied is not introduced. I have to. Therefore, according to the present embodiment, the suspended matter separated from the hollow fiber membrane 2A by the washing by the washing means 6 and 7, the activated carbon membrane containing the organic matter, and the suspended matter filtered by the hollow fiber membrane 2A itself are the raw water W When the raw water W is not introduced into the filtration module 1 in this way, a new suspension E is supplied to the filtration module 1 so that the Since the new activated carbon membrane which does not contain etc. is formed in the hollow fiber membrane 2A, it becomes possible to restart the efficient filtration of the next raw | natural water W promptly after that.

  In addition, in this embodiment, the 1st washing | cleaning means 6 which supplies backwash water (filtrated water T) in the hollow fiber membrane 2A of the filtration membrane 2, and wash | cleans (backwash) in this way, and the filtration module 1 are mentioned. There are provided two cleaning means including a second cleaning means 7 for jetting air (bubbles) around the hollow fiber membrane 2A from the bottom side and cleaning by air scrubbing. Only one of the second cleaning means 6 and 7 may be provided. Further, instead of at least one of the first and second cleaning means 6 and 7, or in addition to the first and second cleaning means 6 and 7, for example, a hollow fiber membrane extending in the longitudinal direction of the filtration membrane 2 There may be provided a third cleaning means for cleaning the filtration membrane 2 by ejecting air (bubbles), cleaning water, or a bubble stream in which air is mixed into the cleaning water from around the 2A or inside the bundle. . Furthermore, when supplying the washing water and the backwashing water in this way, they may contain a chemical solution such as hypochlorite.

  By the way, in the present embodiment, the raw water W is not introduced into the filtration module 1, and the raw water W is filtered after the filtration membrane 2 is washed with the raw water W introduced into the filtration module 1 as described above. Although the state discharged | emitted from 1 was demonstrated, in addition to this, before starting the next filtration operation after completion | finish of a series of filtration operation | work, for example, the filtration operation | work is restarted after maintenance / inspection work, such as replacement | exchange of the filtration membrane 2. Suspension first in the state in which the raw water W is discharged from the filtration module 1 or in the state in which the raw water W before the first filtration after the filtration device is installed in the water purification plant is not introduced. E may be supplied to form an activated carbon membrane, and then the raw water W may be introduced for filtration.

  Next, FIG. 2 and FIG. 3 show the second and third embodiments of the filtration device of the present invention, respectively, and there are parts common to the filtration device of the first embodiment shown in FIG. The same reference numerals are assigned and description thereof is omitted. Here, in the filtration device of the first embodiment, the return pipe 3E is connected to the filtration module 1 as described above, and the raw water W is circulated to the raw water tank 3A. The filtration membrane 2 is a cross-flow type filtration device that filters the raw water W in the direction crossing the flow direction by the hollow fiber membrane 2A, whereas the second and third embodiments The filtration device of FIG. 1 does not include such a return pipe 3E for the raw water W, and the raw water W introduced into the filtration module 1 is completely filtered by the filtration membrane 2 without being circulated and discharged as filtered water T. It is an end-type filtration device.

  Among these, in 2nd Embodiment shown in FIG. 2, the filtration membrane 2 shall be comprised by bundling many hollow fiber membranes 2A extended in the vertical direction similarly to 1st Embodiment. On the other hand, in the third embodiment shown in FIG. 3, a plurality of filtration elements 2C in which a large number of such hollow fiber membranes or the like are bundled are arranged in the casing 1A to form the filtration membrane 2, and the casing 1A has an upper portion in the casing 1A. The hollow fiber membranes and the like of these filtration elements 2C communicate with the provided header portion 2B and are connected to the filtered water discharge means 4, and the lower ends of the filtration elements 2C are connected to the bottom of the casing 1A. An interval is provided without being connected, and a cleaning pipe 7C such as a pipe having a large number of nozzle holes or a sintered pipe having fine pores is laterally provided in the gap. The cleaning pipe 7C is disposed so as to extend in the direction, and the cleaning pipe 7C is connected to the compressor 7B via the valve V10, whereby the second cleaning means 7 in the third embodiment is configured.

  Even in the filtration method according to the second and third embodiments of the present invention using the filtration device configured as described above, except that the raw water W is not circulated to the raw water tank 3A as described above, Similarly, the raw water W is introduced into the filtration module 1 by operations such as introduction of the raw water W, filtration by the filtration membrane 2, washing of the filtration membrane 2 by the cleaning means 6 and 7, and discharge of the raw water W from the filtration module 1. Thereafter, the suspension E in which the activated carbon C is suspended is supplied while being circulated to the filtration module 1 by the supply means 8, and an activated carbon membrane is formed on the hollow fiber membrane 2 A of the filtration membrane 2. Therefore, by introducing the raw water W into the filtration module 1 and performing filtration thereafter, the same effects as those of the first embodiment can be obtained in the filtration devices and filtration methods of the second and third embodiments. Can do. Moreover, in the dead-end type filtration device in which the raw water W in the filtration module 1 is not circulated and the filtration method using the same, the turbidity in the raw water W remains in the filtration module 1. Since clogging of the hollow fiber membrane 2A or the like is likely to occur, it is particularly effective to apply the present invention to such a filtration apparatus and filtration method.

  4 and 5 show fourth and fifth embodiments of the filtration device of the present invention, respectively, and the filtration devices of the first to third embodiments shown in FIGS. The same reference numerals are assigned to the common parts, and the description is omitted. That is, the filtration apparatus according to the first to third embodiments introduces the raw water W around the filtration membrane 2 in the casing 1A in the filtration module 1 and performs pressure filtration to obtain the hollow fiber membrane 2A and the like. In contrast to the external pressure type filtration device that leaches out the filtered water T inside, the filtration devices of the fourth and fifth embodiments are supplied with raw water W inside the filtration membrane 2. By filtering under pressure, the filtered water T leaches out to the outside of the filtration membrane 2, is held around the filtration membrane 2 in the casing 1A, and is discharged.

  Here, the fourth embodiment shown in FIG. 4 is a cross-flow type filtration device as in the first embodiment, and the casing 1A of the filtration module 1 has a header portion 2D at the top and bottom. Is provided. Further, the filtration membrane 2 accommodated in the casing 1A is preferably composed of a tubular membrane or a hollow fiber membrane having a large diameter (hereinafter simply referred to as a tubular membrane 2E). Such a tubular membrane 2E extends in the vertical direction, and upper and lower ends thereof are joined to an upper portion and a bottom portion in the casing 1, and the inside thereof is communicated with the header portion 2D.

  The water supply pipe 3B, the drain pipe 3D of the raw water introduction means 3, the air diffusion pipe 7A of the second cleaning means 7, and the liquid supply pipe 8C of the supply means 8 are connected to the header portion 2D at the bottom of the casing 1A. In addition, the return pipe 3E, the overflow pipe 3F, the intake / exhaust pipe 1B of the casing 1A, and the return pipe 8D of the supply means 8 are connected to the upper header portion 2D. On the other hand, the discharge pipe 4A of the filtered water discharge means 4 is connected to the upper portion of the casing 1A and communicates with the space around the filtration membrane 2 in the casing 1A.

  Further, in the supply means 8 for supplying the suspension E in which the activated carbon C is suspended in the filtration module 1, a filter comprising a perforated plate screen or the like is provided between the valve V12 of the supply pipe 8C and the filtration module 1. 8F is further interposed between the filtration module 1 and the valve V14. This filter 8F captures the activated carbon C in the suspension E supplied to the filtration module 1 from the suspension tank 8A by the liquid supply pump 8B, which has become a mass and has a larger particle size. Therefore, the filter 8F removes the activated carbon C which has become a lump and has a large particle diameter, so that the activated carbon C in the inflow portion to the tubular membrane 2E in the header portion 2D. Clogging can be prevented. In the fifth embodiment shown in FIG. 5, the fourth embodiment is a dead-end type, and the return pipe 3E is not provided, but the overflow pipe 3F is directly connected to the header portion 2D. Except for this, the configuration is the same as that of the fourth embodiment.

  In the fourth and fifth embodiments, the raw water W introduced into the filtration module 1 by the raw water introduction means 3 and the filtration by the supply means 8 in a state where the raw water W is not introduced into the filtration module 1. The suspension E supplied to the module 1 is first supplied to the header part 2D on the lower side of the casing 1A, reaches the upper header part 2B while being filtered through the inside of the filtration membrane 2, and these raw water W and suspension. The filtrate T filtered from the liquid E fills the periphery of the filtration membrane 2 in the casing 1A and is discharged by the filtrate discharge means 4. Of these, when the suspension E is filtered, the filtered water T is sucked and discharged by the suction means 5 provided in the filtered water discharge means 4, while being passed through the tubular membrane 2 E of the filtration membrane 2. Has an activated carbon membrane formed by filtration of the suspension E on its inner peripheral surface.

  In the fourth embodiment of the cross flow type, the raw water W that has reached the upper header portion 2D is circulated to the raw water tank 3A through the return pipe 3E, whereas in the dead end type of the fifth embodiment, The raw water W introduced into the filtration module 1 is not circulated in this way, but is completely filtered by the filtration membrane 2 and discharged as filtered water T. Furthermore, the suspension E supplied in a state where the raw water W is not introduced is circulated to the suspension tank 8A via the return pipe 8D.

  Further, during the cleaning operation in which the filtration membrane 2 is washed by the washing means 6 and 7 while the raw water W is introduced into the filtration module 1, the filtration membrane in the casing 1A is discharged from the discharge pipe 4A by the first washing means 6. By supplying clear filtered water T as backwash water around 2, the filtered water T seeps into the inside of the tubular membrane 2E, and the turbidity filtered by the tubular membrane 2E and its inner peripheral surface The activated carbon film formed in the above is peeled off together with the adsorbed turbidity. On the other hand, in the second cleaning means 7, air is supplied as air bubbles from the header 2D at the bottom of the casing 1A into the tubular membrane 2E of the filtration membrane 2 by the compressor 7B. Peel from the inner peripheral surface. Air is discharged from the intake / exhaust pipe 1B. In addition, the raw water W overflowed from the casing 1A during this washing operation is discharged from the overflow pipe 3F as the suspended drainage D, and after the washing operation is completed, from the drain pipe 3D connected to the header part 2D at the bottom of the casing 1A. The raw water W inside the filtration membrane 2 (tubular membrane 2E) of the filtration module 1 is discharged as a suspended drainage D.

  Then, when the raw water W is discharged from the filtration module 1 in this way and the raw water W is not introduced into the filtration module 1, the supply means 8 suspends the raw water W in the filtration module 1. By supplying E, an activated carbon membrane is formed on the inner peripheral surface of the tubular membrane 2E of the filtration membrane 2 as described above. After that, the raw water W is introduced into the filtration module 1 and filtered from the inside of the tubular membrane 2E. By performing the above, according to the filtration device of the fourth and fifth embodiments and the filtration method using the filtration device, the same effects as those of the first to third embodiments can be obtained. However, in such an internal pressure type filtration device, clogging is likely to occur inside the filtration membrane 2 through which the raw water W and the suspension E introduced into the filtration module 1 are passed, and therefore the filter 8F as described above is provided. Of course, it is desirable that the dead-end type filtration apparatus and filtration method as in the fifth embodiment be used for the final stage filtration of purified water with less turbidity.

It is a figure which shows 1st Embodiment of the filtration apparatus of this invention. It is a figure which shows 2nd Embodiment of the filtration apparatus of this invention. It is a figure which shows 3rd Embodiment of the filtration apparatus of this invention. It is a figure which shows 4th Embodiment of the filtration apparatus of this invention. It is a figure which shows 5th Embodiment of the filtration apparatus of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Filtration module 1A Casing 2 Filtration membrane 3 Raw water introduction means 4 Filtration water discharge means 5 Suction means 6 1st washing means 7 2nd washing means 8 Activated carbon suspension supply means V1-V14 Valve W Raw water T Filtrated water C Activated carbon E Suspension

Claims (10)

A filtration module in which a filtration membrane is housed in the casing to filter the filtered water from the raw water, a raw water introduction means connected to the filtration module to introduce the raw water, and a filtration connected to the filtration module to discharge the filtered water A filtration comprising: water discharge means; and activated carbon suspension supply means for supplying a suspension in which activated carbon is suspended in the filtration module in a state where the raw water is not introduced into the filtration module. apparatus. The filtration apparatus according to claim 1, wherein the activated carbon suspension supply means supplies the suspension while circulating the suspension between the filtration module and the suspension tank of activated carbon. The filtration device according to claim 1 or 2, wherein the filtration water of the filtration module is used as the water used for suspending the activated carbon. The concentration of the said activated carbon in the said suspension is made into the range of 0.1-100 mg / l, The filtration apparatus in any one of Claims 1-3 characterized by the above-mentioned. The said filtrate water discharge means is equipped with the suction means which is connected to this filtration module in the state which supplied the said suspension to the said filtration module, and attracts filtrate water. The filtration device according to claim 4. The said filtration module is equipped with the washing | cleaning means which wash | cleans the said filtration membrane in the state in which the said raw | natural water was introduce | transduced in this filtration module, The Claim 1 characterized by the above-mentioned. Filtration device. The at least one of the aeration apparatus for scrubbing installed in the casing and the back pressure washing apparatus for the filtration membrane connected to the filtration module is provided as the washing means. Filtration equipment. It is a filtration method using the filtration apparatus in any one of Claims 1-7, Comprising: In the state in which the said raw | natural water is not introduce | transduced into the said filtration module, it is this filtration module by the said activated carbon suspension supply means. The suspension in which activated carbon is suspended is supplied, and the suspension is filtered through the filtration membrane to form the membrane or layer of the activated carbon on the filtration membrane, and then the raw water is introduced into the filtration module. And filtering. 9. The filtration method according to claim 8, wherein the suspension is filtered through the filtration membrane while being supplied to the filtration module while being circulated between the suspension modules by the activated carbon suspension supply means. . After the raw water is filtered by the filtration module, the filtration membrane is washed in a state where the raw water is introduced into the filtration module, and then the raw water is discharged and the raw water is not introduced into the filtration module. The filtration method according to claim 8 or 9, wherein the filtration method is in a state.

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