JP6191464B2 - Operation method of turbidity removal membrane module - Google Patents

Description

  The present invention relates to a method for operating a turbidity membrane module used for treating filtered water (raw water) with a turbidity membrane to obtain filtered water.

  A filtration device using a turbidity membrane has advantages such as high turbidity and sterilization performance, ease of operation and maintenance, energy saving, and space saving. And widely used in the production of industrial water. In addition, filtration devices using turbidity membranes can be used for the production of pre-treatment water for reverse osmosis membrane modules used for seawater desalination, or for clarification, sterilization and reuse of post-treatment water for biological treatment of sewage wastewater. Its use is expanding in various fields such as the production of pre-treated water for reverse osmosis membrane modules used for manufacturing.

  For example, Patent Document 1 or 2 discloses a turbidity removal membrane. Patent Documents 3, 4 and 5 disclose a turbidity removal membrane module. Patent Document 6 or 7 discloses a water making device or a water making method using a turbidity membrane module, and a method for cleaning the turbidity membrane module.

  A turbidity removal membrane module usually has the following structure. The turbidity membrane module used for carrying out the operation method of the turbidity membrane module of the present invention also has the same structure.

  That is, the turbidity-eliminating module is usually composed of a case and a turbidity-removing membrane housed in the case. The case includes a first fluid circulation port that communicates with a treated water passage including a surface that contacts the treated water (raw water) of the turbidity removal membrane, and a filtered water passage including a surface that contacts the filtered water of the turbidity removal membrane. A second fluid circulation port leading to is provided. If necessary, the case is provided with a third fluid circulation port that leads to a space including a surface that contacts the water to be treated of the turbidity removal membrane.

  In this turbidity membrane module, at one end portion (upper end portion) of the turbidity membrane, an opening of the filtrate water channel is provided, and fluid flows between the treated water channel and the filtrate water channel. The opening end of the turbidity membrane is formed by a support of the turbidity membrane that blocks the turbidity membrane and fixes the turbidity membrane to the case.

  Further, the turbidity is eliminated by a sealing member that seals the end of the filtrate flow path opposite to the opening of the filtrate flow path at the other end (lower end) of the turbidity removal membrane. A sealed end of the film is formed.

  In the filtration step of obtaining filtered water from the treated water, the first fluid circulation port is used as a treated water supply port for supplying the treated water to the treated water channel. In addition, the second fluid circulation port is used as a filtrate drainage port for discharging filtrate from the filtrate channel through the treated water passing through the turbidity membrane. At this time, when there is surplus water to be treated in the case, the third fluid circulation port is used as a drain for discharging the surplus water to be treated from the water flow path.

  In the backwashing process for removing turbidity adhering to the turbidity membrane from the turbidity film, the second fluid circulation port is prepared separately from the filtered water obtained in the filtration process or the filtered water. Clarified water, that is, wash water (backwash water) is used as a backwash water supply port for supplying the filtrate water flow path. The backwash water passes from the inner side of the turbidity membrane (the filtered water flow path side) through the turbidity membrane to the outer side of the turbidity membrane (the treated water flow path side), and becomes used backwash water. The first fluid circulation port or the third fluid circulation port is used as a backwash water drain port for discharging used backwash water. The filtered water and the clarified water used in backwashing are used as synonyms unless otherwise specified.

  When the turbidity removal membrane needs to be cleaned with gas, that is, when it needs to be washed with air, the first fluid circulation port is normally used as a gas supply port for supplying gas to the treated water flow path. 3 fluid circulation ports are used as gas discharge ports for discharging the gas used for cleaning. In the following, the air washing gas may be described using the most commonly used air.

  An example of such a turbidity-eliminating module is shown in FIG. In the turbidity removal membrane module 14a shown in FIG. 1, the turbidity removal membrane 1 is a turbidity removal membrane formed by a bundle of many hollow fibers. The turbidity removal membrane 1 is accommodated in a case (pressurized container) 4. A sealing end 3 is formed at one end (lower end) of the turbidity removal membrane 1, and an open end 2 is formed at the other end (upper end). The raw water is filtered from the outside of the turbidation membrane 1 through the turbidation membrane 1 from the outside to the inside. The filtered water inside the turbidity removal membrane 1 is taken out from the open end 2. This hollow fiber turbidity membrane module 14a is an external pressure type hollow fiber turbidity membrane module.

  As a cleaning method for such a turbidity removal membrane module 14a, filtration is performed in a direction opposite to the filtration direction, that is, from the inside of the turbidity removal membrane 1 (filtrated water flow path side) to the outside of the turbidity removal membrane 1 (treated water flow path side). In general, backwashing that allows washing water such as water or clarified water to permeate and air washing that introduces gas (generally air) as bubbles to the outside of the turbidity removal membrane (on the treated water channel side) are generally performed. .

  As shown in FIG. 4, the turbidity membrane module has a sealed end 3 having a water inlet 6 serving as an inlet for water to be treated (raw water) or air, as shown in FIG. In general, the turbidity removal membrane 1 is installed on the filtration device F1 in a state where the opening end 2 having an opening through which filtered water flows is positioned above the sealing end 3.

  However, when the opening end 2 is set to the upper side in this way, in backwashing, the flow resistance of the filtrate flow path through which the backwash water of the turbidity removal membrane 1 flows is small in the vicinity of the upper opening end 2. Although the backwash water flows well, on the other hand, in the vicinity of the sealing end 3, the flow resistance of the filtrate flow path through which the backwash water of the turbidity removal membrane 1 flows is large, so the backwash water is difficult to flow. As a result, there is a problem that a sufficient cleaning effect of the turbidity removal film 1 in the vicinity of the sealing end 3 cannot be obtained. Further, even in the air washing, the end of the turbidity removal film 1 is less subject to vibration due to the flow of gas (air). There was a problem that turbidity remained and accumulated.

JP4835221B2 JP3760838B2 JP2006-231146A JP2007-124552A US6,911,147B2 JP2011-125822A WO2011 / 122289A1

  An object of the present invention is to provide a method for operating a turbidity membrane module that improves the cleaning properties of the turbidity membrane module and can prevent a decrease in the filtration performance of the turbidity membrane in the filtration step as much as possible.

  The operation method of the turbidity removal membrane module of the present invention for solving the above problems is as follows.

First aspect:
A case and a turbidity membrane accommodated in the case, and having one end portion of the turbidity membrane having a sealed end portion in which the filtrate water flow path of the turbidity membrane is sealed, and the other end The operation method of the turbidity membrane module having an open end portion in which the filtrate water flow path is opened at the portion, wherein the water to be treated is allowed to permeate the turbidity membrane from the outside to the inside of the turbidity membrane. By filtering the treated water and removing the obtained filtrate from the opening end, and changing the position of the case relative to the horizontal direction in the vertical direction, the position of the sealing end Is positioned higher than the position of the opening end, at least the sealing end is exposed to the atmosphere, and the opening end is positioned in the water to be treated. By supplying clear water, The method of operating dividing Nigomaku modules from inside the clarified water is extruded to the outside, it has a sealing edge height position backwashing step of performing backwash of the removal Nigomaku.

Second aspect:
A turbidity membrane housed in the case, and having one end of the turbidity membrane having a sealed end where the filtrate water flow path of the turbidity membrane is sealed, and the other end In the operation method of the turbidity-removing membrane module having an open end where the filtrate flow path is opened in a part, where the position of the open end is higher than the position of the sealed end, Filtration step of filtering the water to be treated by allowing the water to be treated to permeate the turbidity membrane from the outside to the inside of the turbidity membrane, and removing the obtained filtered water from the opening end, and In a state where the position of the opening end is higher than the position of the sealing end, by supplying clarified water from the opening end, extruding clarified water from the inside of the turbidity removal membrane, The turbidity membrane module having an open end high position backwashing process for backwashing the turbidity membrane. The position of the sealing end is higher than the position of the opening end by changing the position of the turbidity-removing membrane module in which the rolling cycle has been repeated at least once with respect to the horizontal direction of the case in the vertical direction. At the same time, at least the sealing end is exposed to the atmosphere, and the opening end is in contact with water, and clarified water is supplied from the opening end. The operation method of the turbidity membrane module which has the sealing edge part high position backwashing process which extrudes the said clear water from the inner side to the outer side, and backwashes the said turbidity membrane.

  In the second aspect, before and after the opening end portion high position backwashing step, or simultaneously with the opening end portion high position backwashing step, gas is introduced into the turbidity removal membrane module from the sealing end portion side. It is preferable to perform an air washing step to be introduced.

  In the first or second aspect, it is preferable that the turbidity-eliminating film is brought into contact with a chemical solution for a certain period of time before the sealing edge high position backwashing step.

  In the first or second aspect, in the sealing end portion high position backwashing step, a portion less than ½ of the length of the turbidity removal film is exposed to the atmosphere from the sealing end portion. It is preferable that the state is maintained.

  In the first or second aspect, the water level of the water to be treated with respect to the turbidation membrane in the case by discharging the water to be treated from the case in the sealing edge high position backwashing step. It is preferable that the turbidity-removing membrane is back-washed while lowering stepwise or continuously.

  In the first or second aspect, it is preferable that the turbidity removal membrane module is an external pressure pressurized hollow fiber membrane module.

  According to the operation method of the turbidity removal membrane module of the present invention, the sealed end is positioned higher than the open end, the sealed end is exposed to the atmosphere, and the open end is covered. Since the turbidity membrane is backwashed in a state of being located in the treated water, that is, the turbidity membrane module is efficiently washed by the sealing end high position backwashing step. In particular, the turbidity adhering to the turbidity film near the sealing end is efficiently removed.

FIG. 1 is a schematic longitudinal sectional view of an example of a turbidity removal membrane module used in the practice of the present invention. FIG. 2 is a schematic longitudinal sectional view of an example of another turbidity-eliminating module used for carrying out the present invention. FIG. 3 is a schematic longitudinal sectional view of an example of still another turbidity-eliminating module used in the practice of the present invention. FIG. 4 is a schematic flow diagram for explaining an example of the filtration step in the implementation of the present invention. FIG. 5 is a schematic flow diagram for explaining an example of the sealing edge high position backwashing step in the implementation of the present invention. FIG. 6 is a schematic flowchart for explaining another example of the sealing end high position backwashing step in the embodiment of the present invention.

  Hereinafter, several embodiments of the present invention will be described with reference to the drawings. The present invention is not limited to these examples.

  Examples of water to be treated (raw water) subjected to filtration in the practice of the present invention include various types of water such as seawater, river water, ground water, and treated wastewater.

  1, 2, and 3 will be used to describe different embodiments of the turbidity-removing membrane module used in the practice of the present invention.

  The turbidity removal membrane module 14 a shown in FIG. 1 includes a turbidity removal membrane 1 formed of a bundle of a case (cylindrical case) 4 and a plurality of hollow fiber membranes housed inside the case 4. Each hollow fiber membrane is embedded in the potting material at the upper end portion of the turbidity removal membrane 1, and each hollow portion at the upper end portion thereof is opened on the upper surface of the potting material. The side peripheral surface of the potting material is fixed to the inner peripheral surface of the case 4. In this state, the opening end 2 of the turbidity removal film 1 is formed by the potting material. Filtrated water is taken out from the open end 2.

  At the lower end portion of the turbidity removal membrane 1, each hollow fiber membrane is embedded in a potting material, and each hollow portion at the lower end portion thereof is sealed with the potting material. The side peripheral surface of the potting material is fixed to the inner peripheral surface of the case 4. In this state, the sealing end portion 3 of the turbidity removal film 1 is formed by the potting material. At the center of the potting material forming the sealing end 3, a water passage 6 through which the water to be treated flows is provided.

  In the turbidity removal membrane module 14a, the water to be treated supplied to the outside of the turbidity removal membrane 1 is filtered by permeating from the outer surface of the turbidity removal membrane 1 to the surface of the inner hollow portion to become filtered water. The filtered water flows out from the opening of each hollow portion at the opening end 2.

  The turbidity removal membrane module 14a includes a treated water supply nozzle (treated water supply port) 5 for supplying treated water, a filtered water discharge nozzle (filtered water discharge port) 8 for taking out filtered water, and surplus in the case 4 There is a drain nozzle (drain port) 7 for discharging the water.

  FIG. 2 shows a turbidity membrane module 14b having a structure different from that of the turbidity membrane module 14a shown in FIG. In FIG. 2, the turbidity removal membrane module 14b has a structure in which the turbidity removal membrane 1 is bent in a U shape around the liner 10 and folded, and only both ends are potted with a potting material. By this potting material, an opening end 2 similar to the opening end 2 in the turbidity-eliminating membrane module 14a of FIG. 1 is formed. The folded portion 9 of the turbidity removal film 1 may be fixed by a liner 10. A sealed end portion having the same function as the sealed end portion 3 in the turbidity removal membrane module 14a of FIG. 1 is formed by the folded portion 9 of the turbidity removal membrane 1 around the liner 10.

  FIG. 3 shows a turbidity membrane module 14c having a structure different from that of the turbidity membrane module 14a shown in FIG. The turbidity removal membrane module 14c shown in FIG. 3 has a drain nozzle (drain outlet) 11 provided in the case 1 near the sealing end 3 in the turbidity removal membrane module 14a shown in FIG. It is different from the turbidity removal membrane module 14a shown in FIG.

  In FIG. 4, an example of the filtration apparatus used for implementation of the operating method of the turbidity-elimination membrane module of this invention is shown. In FIG. 4, the filtration device F1 includes the turbidity removal membrane module 14a, the raw water tank 12, and the filtrate water tank 16 shown in FIG. The raw water tank 12 and the turbidity membrane module 14a are connected to the raw water supply line L1 so that the raw water (treated water) RW is supplied from the raw water tank 12 to the raw water (treated water) supply nozzle 5 of the turbidity membrane module 14a. Are combined.

  The turbidity removal membrane module 14a and the filtrate water tank 16 are coupled by a filtrate water supply line L2 so that the filtrate FW is supplied from the filtrate water discharge nozzle 8 of the turbidity membrane module 14a to the filtrate water tank 16. . A drain line L3 is coupled to the drain nozzle 7 of the turbidity removal membrane module 14a so as to drain the water in the case 4 out of the system.

  The raw water supply line L1 is provided with a raw water pump 13 and a raw water valve 23 in this order from the raw water tank 12 toward the raw water (treated water) supply nozzle 5. A filtrate water valve 24 is provided in the filtrate water supply line L2. A drainage valve 15 is provided in the drainage line L3.

  The raw water supply line L1 has a branch point J1 between the raw water valve 23 and the raw water (treated water) supply nozzle 5. The filtrate water tank 16 and the branch point J1 are connected by a backwash water supply line LA so that the filtrate water FW is supplied to the raw water supply line L1. The backwash water supply line LA is provided with a backwash pump 17 and a backwash valve A25 in this order from the filtrate water tank 16 toward the branch point J1.

  The backwash water supply line LA has a branch point J2 between the backwash pump 17 and the backwash valve A25. Further, the filtrate supply line L2 has a branch point J3 between the filtrate discharge nozzle 8 and the filtrate water valve 24. The branch point J2 and the branch point J3 are connected by a backwash water supply line LB so that the filtrate FW is supplied to the filtrate water supply line L2. A backwash valve B18 is provided in the backwash water supply line LB.

  The filtrate water supply line L2 has a branch point J4 between the filtrate discharge nozzle 8 and the branch point J3. An air discharge line L4 is coupled to the branch point J4 so that air (gas) in the case 4 is discharged out of the system. An air vent valve 19 is provided in the air discharge line L4.

  The raw water supply line L1 has a branch point J5 between the branch point J1 and the raw water (treated water) supply nozzle 5. An air supply line L5 is coupled to the branch point J5 so that air (gas) used for air washing is supplied into the case 4. An air supply valve 26 is provided in the air supply line L5.

  Next, the operation method of the turbidity removal membrane module in the filtration apparatus F1 shown in FIG. 4 will be described.

  In the filtration step in the filtration device F1, the raw water (treated water) RW stored in the raw water tank 12 is passed through the water inlet 6 provided in the sealed end 3 by the raw water pump 13 to remove the turbidity membrane. The raw water (treated water) is filtered by the turbidation membrane 1 of the turbidity membrane module 14a and supplied to the module 14a, and the obtained filtered water FW passes through the opening formed in the opening end 2. This is performed by being stored in the filtrate water tank 16.

  In this filtration step, the raw water valve 23 and the filtrate water valve 24 are open, and the drain valve 15, the backwash valve A25, the backwash valve B18, and the air supply valve 26 are closed. The air vent valve 19 may be open or closed.

  This filtration step is a step of supplying raw water (treated water) RW from the raw water tank 12 to the turbidity membrane module 14a, and raw water (treated water) from the raw water (treated water) side of the turbidity membrane 1 to the filtered water side. It consists of a step of filtering RW and a step of supplying filtered water FW to the filtered water tank 16. The filtration time can be selected to an arbitrary length. However, from the viewpoint of preventing excessive accumulation of turbidity in the turbidity removal membrane module 14a, it is desirable that one filtration time is about 15 minutes to 2 hours. When ending the filtration process, the raw water pump 13 is stopped and the raw water valve 23 and the filtered water valve 24 are closed.

  In this filtration step, the height relationship between the position of the opening end 2 and the position of the sealing end 3 of the turbidity removal membrane 1 is not limited at all. That is, the filtration step may be performed in a state where the position of the sealing end 3 and the position of the opening end 2 of the turbidity removal membrane 1 are the same height, or the position of the sealing end 3 is opened. The filtration step may be performed in a state lower than the position of the end 2, or the filtration step may be performed in a state where the position of the sealed end 3 is higher than the position of the opening end 2. Good.

  Next, the washing | cleaning process of the turbidity removal membrane 1 in the filtration apparatus F1 is demonstrated using FIG.

  First, the position of the sealing end 3 is higher than the position of the opening end 2, and preferably, the sealing end 3 and the opening end 2 are aligned vertically. In the filtration step, when the filtration step is performed with the position of the sealing end 3 higher than the position of the opening end 2, the washing step can be carried out as it is.

  However, in other cases, the longitudinal direction (vertical direction) of the turbidity removal membrane module 14a is rotated so that the position of the sealing end 3 of the turbidity removal membrane 1 is higher than the position of the opening end 2. To do.

  In this case, as shown in FIG. 5, the downstream end of the raw water supply line L1 is connected to the raw water (treated water) supply nozzle 5 at the downstream end of the raw water supply line L1 as shown in FIG. The joining state is changed so as to join to 8. The joining state may be changed manually, for example, mechanically using an automatic switching means for the position of the opening so that one of the facing openings faces the other opening. Preferably, it is done.

  Next, as shown in FIG. 5, the vertical relationship between the sealing end 3 and the opening end 2 shown in FIG. 4 is completely reversed, the sealing end 3 is located on the upper side, and the opening end 2 is The backwashing process in the state located on the lower side, that is, the sealing edge high position backwashing process will be described.

  In this state, the air vent valve 19 and the drain valve 15 are opened, and at least a part of the raw water (treated water) side of the turbidity membrane module 14a is drained from the drain nozzle 7 to seal the turbidity membrane 1. The end 3 is exposed to the atmosphere.

  Next, the backwash valve A25 is opened, the backwash pump 17 is operated, and the filtered water FW is allowed to permeate from the filtered water side of the turbidity membrane 1 to the raw water (treated water) side. Backwashing is performed. This backwashing process is a sealing edge part high position backwashing process. At this time, the backwash drainage that has permeated to the raw water (treated water) side is drained from the drain valve 15 so that the sealed end 3 of the turbidity removal membrane 1 is always exposed to the atmosphere. In this state, the backwash valve A25, the drain valve 15, and the air vent valve 19 are open, and the raw water valve 23, the filtrate water valve 24, the backwash valve B18, and the air supply valve 26 are closed.

  The sealing end high position backwashing step supplies the filtrate FW from the filtrate tank 16 to the turbidity membrane module 14a with the sealing end 3 of the turbidity membrane 1 exposed to the atmosphere, The water is allowed to pass from the filtered water side to the raw water (treated water) side and discharged from the drain nozzle 7 to the raw water (treated water) side.

  At this time, since the raw water (treated water) side of the turbidity removal membrane 1 is exposed to the atmosphere near the sealing end 3, there is no resistance due to water pressure. Since filtered water permeate | transmits selectively from the exposed part, the high cleaning effect of the turbidity removal membrane 1 in the part is acquired.

  On the other hand, the outer side of the turbidity membrane 1 is located at the upper part from the lower part of the turbidity membrane 1 near the open end 2 where the raw water (treated water) side of the turbidity membrane 1 is filled with water. Since there is resistance due to water pressure, filtered water is difficult to permeate through the turbidity removal membrane 1. Therefore, the state where the portion of the turbidity-dissolving film 1 near the sealing end 3 that has been difficult to be cleaned in the past is intensively cleaned is formed by the sealing end high position backwashing process.

  The sealing edge high position backwashing process (hereinafter, this process may be referred to as the backwashing process (A)) may be performed every time after the filtration process for a certain period of time is completed. It may be done from time to time in combination with the method.

  When performing in combination with another cleaning method, it is operated for several months to several years, and after the turbidity is sufficiently accumulated at the sealing end of the turbidity-eliminating membrane module, the backwashing step (A) is performed. You may go. In this case, when the backwashing step (A) is performed, the turbidity accumulated at the sealing end is efficiently removed, and the time required to remove the turbidity is shortened compared to the conventional cleaning method. In addition, the amount of clarified water used and the amount of chemical used can be reduced.

  The enforcement time of a backwash process (A) can be determined arbitrarily. However, when the backwashing step (A) is performed after the completion of each filtration step or after several times combining the filtration step and another washing step, the backwashing step is performed from the point of operation availability. The enforcement time of (A) is preferably 10 to 60 seconds. On the other hand, in the case where the turbidity is sufficiently accumulated at the sealed end of the turbidity removal membrane module and the backwashing step (A) is performed, the backwashing step is performed to remove the turbidity at the sealed end. The enforcement time of (A) is desirably about 1 to 15 minutes.

  In order to carry out the backwashing step (A) more effectively, the opening degree of the drain valve 15 or the backwashing valve A25 is adjusted or the output of the backwashing pump 17 is adjusted in the backwashing step (A). As a result, a portion less than ½ of the length of the turbidity film 1 is exposed from the sealing end 3 of the turbidity film 1 to the atmosphere, and the remaining part is filled with water. In addition, it is preferable to maintain the water level 20 (see FIG. 5) inside the turbidity removal membrane module.

  On the other hand, in order to efficiently wash the entire turbidity removal membrane 1, it is also beneficial to perform the backwashing step (A) while lowering the water level of the water to be treated stepwise or continuously. Further, the water level may be lowered after the liquid level is maintained for a certain time.

  Whether the liquid level is maintained or the water level is lowered can be arbitrarily selected according to the location where the turbidity is accumulated and the degree thereof. If turbidity accumulates throughout the membrane, it is desirable to perform while lowering the water level. On the other hand, if turbidity is concentrated and accumulated at the sealing end 3 of the turbidity removal membrane module, maintain the water level and thoroughly remove the turbidity in the vicinity of the sealing end 3. Is desirable.

  Next, an operation method of the turbidity membrane module in the filtration device F2 shown in FIG. 6 using the turbidity membrane module 14c shown in FIG. 3 will be described.

  As shown in FIG. 6, in the case of the turbidity removal membrane module 14c provided with the drain nozzle 11 near the sealing end 3, the air vent valve 19 is opened and opened to the atmosphere, and the drain valve 22 is opened. The lower drain valve 15 is opened, and the upper portion of the turbidity membrane module 14c is exposed to the atmosphere as shown by the water level 21 inside the turbidity membrane module, and below that. The backwashing step (A) is performed in a state where the portion is filled with water. Subsequently, the entire drainage membrane 1 is backwashed by continuing the backwashing while opening the lower drain valve 15 so that the whole of the turbidity membrane 1 is exposed to the atmosphere. .

  In addition, in addition to the same line structure as the line structure in the filtration apparatus F1 shown in FIG. 4, the structure of the line through which water and gas (air) in the filtration apparatus F2 shown in FIG. 6 distribute | circulate the water in case 4 outside the system. It has a drainage line L6 coupled to the drainage nozzle 11 of the turbidity removal membrane module 14c so as to be discharged. A drain valve 22 is provided in the drain line L6.

  Next, an embodiment of a more effective operation method of the turbidity-eliminating membrane module of the present invention will be described.

  First, as shown in FIG. 4, after performing the above-described filtration step with the open end 2 facing up, the raw water valve 23 and the filtered water valve 24 with the open end 2 still facing up. Is closed, the backwash valve B18 and the drainage valve 15 are opened, the backwash pump 17 is operated, clarified water is supplied from the open end 2, and the clarified water is pushed out from the inside to the outside of the turbidity removal membrane 1. An opening edge high position backwashing step (hereinafter, this step may be referred to as a backwashing step (B)) is performed. The operation cycle consisting of these filtration steps and backwashing step (B) is repeated.

  At this time, in the backwashing step (B), due to the flow path resistance inside the turbidity removal membrane 1, the upper portion of the turbidity removal membrane 1 near the opening end 2 is compared with the lower portion near the sealing end 3. Since the amount of water that permeates through the turbidity removal membrane 1 is increased, the cleaning effect of the portion near the opening end 2 of the turbidity removal membrane 1 is higher than that near the sealing end 3. Therefore, when the operation cycle including the filtration step and the backwashing step (B) is performed a plurality of times, turbidity gradually accumulates in the vicinity of the sealed end portion 3 of the turbidity removal membrane 1.

  Here, the longitudinal direction of the turbidity removal module 14a is rotated, and as shown in FIG. 5, the backwashing is performed in a state where the sealing end 3 of the turbidity removal membrane module 14a is positioned above the opening end 2. Step (A) is performed. This makes it possible to remove the turbidity accumulated at the sealing end 3 from the turbidity removal film 1.

  Further, before or after the backwashing step (B) or simultaneously with the backwashing step (B), the air supply valve 26 is opened and air (gas) is passed through the water inlet 6 to the turbidity removal membrane module 14a. You may perform the air washing process which supplies. By performing this air washing step, the turbidity removal effect of the turbidity film 1 is further enhanced by the shearing force due to the rise of air (gas) and the violent shaking of the turbidity film 1.

  However, in the vicinity of both end portions of the turbidity removal membrane 1, the turbidity removal membrane 1 is fixed by the opening end 2 and the sealing end 3, so that the turbidity of the turbidity removal membrane 1 is small and the cleaning effect by the air washing is small. Become. As a result, turbidity was more likely to be selectively accumulated in the sealing end 3. This problem is solved by performing the backwash process (A). That is, the turbidity accumulated in the sealed end 3 can be removed from the turbidity removal film 1 by performing the backwashing step (A).

  Prior to the backwashing step (A), the turbidity removal effect in the backwashing step (A) can be further enhanced by bringing the turbidity removal film 1 into contact with the chemical solution for a certain period of time.

  The chemical solution is selected after appropriately selecting a concentration and a contact time that do not deteriorate the turbidity removal membrane. A chemical solution containing at least one of sodium hypochlorite, chlorine dioxide, chloramine, hydrogen peroxide, ozone and the like is preferably used because it has a high cleaning effect on turbid substances containing organic substances. In addition, a chemical solution containing at least one of hydrochloric acid, sulfuric acid, nitric acid, citric acid, oxalic acid, and the like is preferably used because it has a high cleaning effect on aluminum, iron, manganese, and the like.

  The clarified water used in the backwashing step (A) or the backwashing step (B) is not limited to filtered water obtained by filtration through a turbidity membrane, but may be tap water, pure water, ultrapure water, or the like. Water can be used. In addition, in order to enhance the cleaning effect, it is beneficial that the clear water used contains the above chemical solution.

  As a form of the turbidity removal membrane 1, a hollow fiber membrane type, a flat membrane type, a spiral type, or a tubular type can be used. The hollow fiber membrane mold is preferable from the viewpoint of the cleaning effect brought about by the practice of the present invention, and the hollow fiber membrane mold is preferable from the viewpoint of cost reduction. The membrane filtration method may be a whole-volume filtration type module or a cross flow filtration type module.

  However, the total amount filtration type module is preferable from the viewpoint of low energy consumption. The so-called “pressurization type” in which the turbidity membrane module is loaded with a turbidity membrane in a pressure-resistant case that can produce a large amount of water by feeding at a high pressure is preferably used. .

  As the filtration method of the hollow fiber membrane module, an external pressure method of performing filtration from the outside to the inside of the hollow fiber membrane is preferably used.

  The position of the drain nozzle 7 is not particularly limited. In the back washing step (A), the drain nozzle 7 is disposed so that raw water (treated water) and washing water (back washing water) inside the turbidity membrane module can be drained as much as possible. It is preferable that the turbidity removal membrane 1 is provided near the opening end 2.

  The turbidity removal membrane 1 is a microfiltration membrane capable of blocking particles or polymers having a particle size of 0.1 μm or more, or a particle or polymer having a particle size of 2 nm or more and less than 0.1 μm. An outer filtration membrane is preferred.

  The material of the microfiltration membrane and / or the ultrafiltration membrane used for the turbidity filtration membrane includes polysulfone, polyethersulfone, polyacrylonitrile, polyimide, polyetherimide, polyamide, polyetherketone, polyetheretherketone, polyethylene, Examples thereof include polypropylene, ethylene-vinyl alcohol copolymer, cellulose, cellulose acetate, polyvinylidene fluoride, ethylene-tetrafluoroethylene copolymer, polytetrafluoroethylene, and composite materials thereof.

  In particular, polyvinylidene fluoride has excellent chemical resistance, and therefore the filtration function of the microfiltration membrane and / or ultrafiltration membrane can be improved by periodically cleaning the microfiltration membrane and / or ultrafiltration membrane with chemicals. It is preferably used because it recovers and extends the life of the pretreatment membrane module.

  The case 4 of the turbidity membrane filtration module is made of, for example, polyolefin such as polyethylene, polypropylene, polybutene, polytetrafluoroethylene (PTFE), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), fluorinated ethylene. Fluorine-based resins such as polypropylene copolymer (FEP), ethylenetetrafluoroethylene copolymer (ETFE), polychlorotrifluoroethylene (PCTFE), ethylene trifluoride-ethylene copolymer (ECTFE), polyvinylidene fluoride (PVDF), and Chlorine resins such as polyvinyl chloride and polyvinylidene chloride, polysulfone resins, polyether sulfone resins, polyallyl sulfone resins, polyphenyl ether resins, acrylonitrile Tajien - styrene copolymer resin (ABS), acrylonitrile - styrene copolymer resin, polyphenylene sulfide resin, polyamide resin, polycarbonate resin, polyether ketone resin, polyether ether ketone resin is used alone or in combination. Other than the resin, aluminum, stainless steel, and the like are preferable, and a composite material such as a resin-metal composite, a glass fiber reinforced resin, and a carbon fiber reinforced resin may be used.

    According to the operation method of the turbidity removal membrane module of the present invention, the sealed end is positioned higher than the open end, the sealed end is exposed to the atmosphere, and the open end is covered. Since the turbidity membrane is backwashed in a state of being located in the treated water, that is, the turbidity membrane module is efficiently washed by the sealing end high position backwashing step. In particular, the turbidity adhering to the turbidity film near the sealing end is efficiently removed.

1: Turbidity membrane 2: Open end 3: Sealed end 4: Case (cylindrical case)
5: Raw water (treated water) supply nozzle (treated water supply port)
6: Water outlet 7: Drain nozzle (drain)
8: Filtrated water discharge nozzle (filtrated water discharge port)
9: Folding part of the turbidity removal membrane 10: Liner 11: Drain nozzle (drain port)
12: Raw water tank 13: Raw water pump 14a, 14b, 14c: Turbidity removal membrane module 15: Drain valve 16: Filtrated water tank 17: Backwash pump 18: Backwash valve B
19: Air vent valve 20: Water level inside the turbidity membrane module 21: Water level inside the turbidity membrane module 22: Drain valve 23: Raw water valve 24: Filtration water valve 25: Backwash valve A
26: Air supply valve F1, F2: Filtration device FW: Filtration water J1, J2, J3, J4, J5: Branch point L1: Raw water supply line L2: Filtration water supply line L3: Drain line L4: Air discharge line L5: Air Supply line L6: Drainage line LA, LB: Backwash water supply line RW: Raw water (treated water)

Claims (7)

  A case and a turbidity membrane accommodated in the case, and having one end portion of the turbidity membrane having a sealed end portion in which the filtrate water flow path of the turbidity membrane is sealed, and the other end The operation method of the turbidity membrane module having an open end portion in which the filtrate water flow path is opened at the portion, wherein the water to be treated is allowed to permeate the turbidity membrane from the outside to the inside of the turbidity membrane. By filtering the treated water and removing the obtained filtrate from the opening end, and changing the position of the case relative to the horizontal direction in the vertical direction, the position of the sealing end Is positioned higher than the position of the opening end, at least the sealing end is exposed to the atmosphere, and the opening end is positioned in the water to be treated. By supplying clear water, Method of operating dividing Nigomaku modules from inside the clarified water is extruded to the outside, it has a sealing edge height position backwashing step of performing backwash of the removal Nigomaku.   A turbidity membrane housed in the case, and having one end of the turbidity membrane having a sealed end where the filtrate water flow path of the turbidity membrane is sealed, and the other end In the operation method of the turbidity-removing membrane module having an open end where the filtrate flow path is opened in a part, where the position of the open end is higher than the position of the sealed end, Filtration step of filtering the water to be treated by allowing the water to be treated to permeate the turbidity membrane from the outside to the inside of the turbidity membrane, and removing the obtained filtered water from the opening end, and In a state where the position of the opening end is higher than the position of the sealing end, by supplying clarified water from the opening end, extruding clarified water from the inside of the turbidity removal membrane, The turbidity membrane module having an open end high position backwashing process for backwashing the turbidity membrane. The position of the sealing end is higher than the position of the opening end by changing the position of the turbidity-removing membrane module in which the rolling cycle has been repeated at least once with respect to the horizontal direction of the case in the vertical direction. At the same time, at least the sealing end is exposed to the atmosphere, and the opening end is in contact with water, and clarified water is supplied from the opening end. The operation method of the turbidity membrane module which has the sealing edge part high position backwashing process which extrudes the said clear water from the inner side to the outer side, and backwashes the said turbidity membrane.   Before and after the opening edge high position backwashing process or simultaneously with the opening edge high position backwashing process, an air washing process for introducing gas from the sealing end side into the turbidity removal membrane module is performed. The operation method of the turbidity-eliminating membrane module according to claim 2.   The operation method of the turbidity membrane module of Claim 1 or 2 which makes the said turbidity membrane contact a chemical | medical solution for a fixed time before the said sealing edge part high position backwashing process.   3. The sealed end portion high-position backwashing step maintains a state where a portion less than half the length of the turbidity removal film from the sealed end portion is exposed to the atmosphere. An operation method of the turbidity-eliminating membrane module described   In the sealing end high position back washing step, by discharging the treated water from the case, the water level of the treated water with respect to the turbidity membrane in the case is lowered stepwise or continuously. The method for operating the turbidity-eliminating membrane module according to claim 1 or 2, wherein the turbidity-eliminating membrane is backwashed.   The method of operating a turbidity-eliminating module according to claim 1 or 2, wherein the turbidity-eliminating module is an external pressure type pressurized hollow fiber membrane module.

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