JP2000271456A - Spiral type membrane element and method for operating and washing spiral type membrane module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a low cost, easily washable and highly reliable spiral type membrane element, and a method for operating a spiral type membrane module. SOLUTION: The spiral type membrane element 1 is constituted by covering a spiral-shaped membrane element consisting of a plurality of independent or continuous envelope-like membranes wound on the outer peripheral surface of a water collection tube 2 via raw water spacers with a separation membrane and further covering the resultant assembly with an outer peripheral part flow path material. The preferred flow rate of transmission water at filtering by the spiral type membrane element 1 is 0.5-2.0 m3/m2/day and the preferred filtering time is 10-300 minutes. Also, the preferred flow rate of washing water at washing is 1.0-4.0 m3/m2/day and the preferred washing time is 10-300 seconds. In such a range, the ratio of the passing water quantity at filtering to the passing water quantity at back-washing is set to be <=600.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spiral type membrane element and a method for operating and cleaning a spiral type membrane element used in a membrane separation device such as a low pressure reverse osmosis membrane separation device, an ultrafiltration device and a microfiltration device. .

[0002]

2. Description of the Related Art In recent years, a membrane separation technique has been applied to a water purification technique, and a membrane separation technique has been applied as a pretreatment of a reverse osmosis membrane separation system used for seawater desalination and the like.
As a type of membrane used for such membrane separation, a microfiltration membrane or an ultrafiltration membrane capable of obtaining a high amount of permeated water is widely used, but recently, an ultra-low pressure of 10 kgf / cm ² or less has been used. Reverse osmosis membranes that provide a permeate volume have also been developed.

[0003] As a form of a membrane element used for membrane separation, a hollow fiber membrane element is often used in view of a membrane area per unit volume (volume efficiency). However, the hollow fiber membrane element has a disadvantage that the membrane is easily broken, and if the membrane is broken, the raw water mixes with the permeated water and the separation performance is reduced.

On the other hand, there is a spiral type membrane element as a form of a membrane element capable of increasing a membrane area. This spiral type membrane element has an advantage that separation performance can be maintained and reliability is high as compared with a hollow fiber membrane element.

FIG. 14 is a partially cutaway perspective view of a conventional spiral type membrane element, and FIG. 15 is an external perspective view of a conventional spiral type membrane element.

As shown in FIG. 14, a spiral membrane element 21 has an envelope-shaped membrane (bag) by superimposing separation membranes 26 on both surfaces of a permeated water spacer (permeate liquid flow path material) 25 and bonding three sides thereof. Film) 23, and the envelope-shaped film 2
3 is attached to the water collecting pipe 22 formed of a perforated hollow pipe, and is wound spirally around the outer peripheral surface of the water collecting pipe 22 together with the net-shaped (net-shaped) raw water spacer 24 (raw water liquid passage material). Is done.

The raw water spacer 24 is provided for forming a flow path through which raw water passes between the envelope membranes 23. If the thickness of the raw water spacer 24 is small, the filling efficiency of the separation membrane 26 is increased, but clogging with the suspended substance occurs. Therefore, usually, the thickness of the raw water spacer 24 is about 0.7 mm to 3.0 m.
m.

A spiral membrane element using a zigzag corrugated raw water spacer (so-called corrugated spacer) for treating raw water containing a large amount of suspended substances, such as river water, has already been known.

As shown in FIG. 15, the outer peripheral surface of the spiral type membrane element 21 is covered with an exterior material 27 made of FRP (fiber reinforced plastic), a shrinkable tube or the like.
Packing holders 28 called anti-telescopes are respectively attached to both ends.

FIG. 16 is a sectional view showing an example of a conventional method of operating a spiral type membrane element. As shown in FIG. 16, the pressure vessel (pressure-resistant vessel) 30 is composed of a cylindrical case 31 and a pair of end plates 32a and 32b. A raw water inlet 33 is formed on one end plate 32a, and a concentrated water outlet 35 is formed on the other end plate 32b. A permeated water outlet 34 is provided at the center of the other end plate 32b.

A spiral type membrane element 21 having a packing 37 attached near one end of the outer peripheral surface is mounted in a cylindrical case 31, and both open ends of the cylindrical case 31 are sealed with end plates 32a and 32b, respectively. I do. One open end of the water collecting pipe 22 is fitted to the permeated water outlet 34 of the end plate 32b, and an end cap 36 is attached to the other open end.

During the operation of the spiral type membrane element 21, the raw water 51 is introduced into the first liquid chamber 38 from the raw water inlet 33 of the pressure vessel 30. As shown in FIG.
Is supplied from one end face side of the spiral membrane element 21. The raw water 51 flows in the axial direction along the raw water spacer 24, and is discharged as concentrated water 53 from the other end surface side of the spiral membrane element 21. As the raw water 51 flows along the raw water spacer 24, the permeated water 52 that has passed through the separation membrane 26 is collected along the permeated water spacer 25 by the water collecting pipe 2.
2 and discharged from the end of the water collecting pipe 22.

The permeated water 52 is supplied to the pressure vessel 30 shown in FIG.
Is taken out from the permeated water outlet 34 to the outside. Further, the concentrated water 53 is taken out of the second liquid chamber 39 in the pressure vessel 30 through the concentrated water outlet 35 to the outside.

[0014]

When the membrane element is operated, the membrane is clogged by suspended substances in the raw water, and the membrane flux is reduced. Therefore, although clogging is removed by performing chemical cleaning or the like to recover the membrane flux, the labor and cost required for chemical cleaning poses a problem. Therefore, in order to prevent clogging, for example, in a hollow fiber membrane element, backwashing with permeated water or air is periodically performed.

However, in the conventional spiral-type membrane element 21, the following problems occur when backwashing is performed.

FIG. 17 is a partially cutaway perspective view showing a backwashing operation in a conventional spiral type membrane element.
As shown in FIG. 17, the permeated water 52 is introduced from the end of the water collecting pipe 22. Since the outer peripheral surface of the envelope film 23 wound around the water collecting pipe 22 is covered with the exterior material 27, the water collecting pipe 22
The permeated water 52 derived from the outer peripheral surface of the spiral membrane element 21 passes through the envelope-shaped membrane 23, flows in the axial direction inside the spiral membrane element 21 along the raw water spacer 24, and is discharged from the end of the spiral membrane element 21. You. Therefore, even if the backwashing is performed, contaminants such as turbid substances causing clogging of the membrane are easily captured by the raw water spacer 24 before being discharged from the end of the spiral membrane element 21. There is a problem that it is not sufficiently removed.

Further, a gap existing between the inner peripheral surface of the cylindrical case 31 of the pressure vessel 30 of FIG. 16 and the spiral membrane element 21 becomes a dead space S, and a stagnation of fluid (liquid pool) occurs. Spiral type membrane element 21
When used for a long period of time, the fluid remaining in the dead space undergoes metamorphosis. In particular, when the fluid is a liquid containing an organic substance, germs such as microorganisms propagate, and the germs may decompose the organic substance to generate a bad smell or decompose the separation membrane. Leads to a decrease in

Further, in the conventional spiral type membrane element 21, raw water is supplied from one end of the spiral type membrane element 21 and discharged from the other end.
A packing holder 28 is required to prevent the envelope-shaped film 23 wound in 2 from being deformed into a bamboo shoot shape.
In addition, a pressure difference occurs between the raw water inflow side and the concentrated water outlet side due to the pressure loss due to the raw water spacer 24 and the pressure loss due to clogging, and the spiral membrane element 21 is deformed. In order to prevent this deformation, the outer peripheral surface of the envelope-like film 23 wound around the water collecting pipe 22 is covered with an exterior material 27 such as an FRP or a shrinkable tube. These increase component costs and manufacturing costs.

Further, it is necessary to obtain a sufficient film surface linear velocity in order to prevent the formation of cake due to contaminants in raw water, and for that purpose, a sufficient flow rate on the concentration side is required. When the flow rate on the concentration side is increased, the recovery rate per spiral type membrane element is reduced, and the pump for supplying the raw water is large, and the system cost is very large.

An object of the present invention is to provide a spiral-type membrane element and a method for operating a spiral-type membrane module which can be reduced in cost, are easy to clean, and have high reliability.

Another object of the present invention is to provide a cleaning method capable of easily and reliably removing contaminants trapped in a spiral type membrane element.

[0022]

According to a first aspect of the present invention, there is provided a method for operating a spiral type membrane element, wherein a plurality of independent or continuous envelope-shaped membranes are formed on an outer peripheral surface of a perforated hollow tube. A spiral-shaped membrane element wound around a material, an outer peripheral portion of the spiral-shaped membrane element is covered with a liquid-permeable material, and an outer peripheral surface of the liquid-permeable material is wholly or partially formed with an outer peripheral passage. A method of operating a spiral-type membrane element covered with a material, wherein during operation, a stock solution is supplied from at least an outer peripheral side of the spiral-type membrane element, and a permeate is taken out from at least one open end of the perforated hollow tube. In cleaning, a cleaning liquid is introduced from at least one open end of the perforated hollow tube, and the cleaning liquid derived from the outer peripheral surface of the perforated hollow tube is discharged from at least the outer peripheral portion of the spiral membrane element. , In which the ratio of the amount of cleaning liquid having passed through the envelope-like membrane on the amount and the cleaning period of the permeate passing through the envelope-like membrane operating period and 120 or less.

According to the spiral membrane element operating method of the present invention, during operation, the stock solution is supplied from at least the outer peripheral side of the spiral membrane element, and the total amount is filtered. In this case, contaminants are trapped at least at the outer periphery of the spiral-wound membrane element.

When the cleaning liquid is introduced from at least one opening end of the perforated hollow tube, the cleaning liquid derived from the outer peripheral surface of the perforated hollow tube flows through the envelope-like membrane and flows along the raw liquid flow path material. Is discharged from at least the outer peripheral portion of the spiral membrane element. Thereby, the contaminants trapped at least at the outer peripheral portion of the spiral membrane element are separated from the spiral membrane element. Since the spiral membrane element is prevented from spreading between the envelopes at the outer periphery by the liquid permeable material and the outer peripheral passage material, the contaminants adhered to at least the outer periphery of the spiral membrane element during backwashing. A flow path for discharging the gas out of the system is secured. For this reason, the separated contaminants are discharged out of the system together with the cleaning liquid. Therefore, it is possible to uniformly remove at least the contaminants trapped on at least the outer peripheral portion of the spiral-wound membrane element, and it is possible to maintain a constant amount of permeate during operation.

In addition, by setting the ratio of the amount of the permeating liquid permeating the envelope-shaped membrane during the operation period to the amount of the cleaning liquid permeating the envelope-shaped membrane during the cleaning period to be 600 or less, an excessively large amount of the spiral-type membrane element can be obtained. In addition to preventing the load from being applied to the separation membrane, sufficient washing is performed to remove contaminants attached to the outer peripheral portion, and stable operation with high filtration efficiency can be continuously performed for a long time.

Here, the flow rate of the permeated liquid during filtration is 0.5 m ³
/ M ² / day or more and 2.0 m ³ / m ² / day or less, and a filtration time of 10 minutes or more and 300 minutes or less.
Minutes or less. The cleaning liquid is introduced into the perforated hollow tube so that the flow rate of the cleaning liquid at the time of cleaning is 1.0 m ³ / m ² / day or more and 4.0 m ³ / m ² / day or less, and the cleaning time is 10 seconds or more. Preferably, the time is 300 seconds or less. Within such a range, the permeate flow rate during filtration so that the ratio of the amount of the permeate that has permeated through the envelope membrane during the operation period and the amount of the permeate that has permeated the envelope membrane during the cleaning period is 600 or less, Set the filtration time, the flow rate of the cleaning solution and the cleaning time.

In particular, the flow rate of the permeated liquid during filtration is 0.5 m ³ /
More preferably, the stock solution is supplied so as to be at least m ² / day and at most 2.0 m ³ / m ² / day, and the filtration time is at least 10 minutes and at most 30 minutes. In addition, the cleaning liquid is introduced into the perforated hollow tube so that the flow rate of the cleaning liquid at the time of cleaning is 1.0 m ³ / m ² / day or more and 3.0 m ³ / m ² / day or less, and the cleaning time is 30 seconds or more. More preferably, the time is 60 seconds or less. In this case, the ratio of the amount of the permeating liquid that has passed through the envelope membrane during the operation period to the amount of the cleaning liquid that has passed through the envelope membrane during the cleaning period is 120 or less.

By setting the permeate flow rate and the filtration time at the time of filtration as described above, it is possible to prevent an excessive load from being applied to the separation membrane, to suppress the accumulation of contaminants on the outer peripheral portion, and to achieve a stable operation. The operation can be continuously performed for a long time. In addition, it is possible to efficiently obtain a target permeated water amount.

Further, by setting the flow rate of the cleaning liquid and the cleaning time during the cleaning as described above, the contaminants adhering to the outer peripheral portion can be sufficiently removed, and the stable operation can be continuously performed for a long period of time. At the same time, it is possible to suppress a decrease in filtration efficiency.

Further, since dead space is not formed in the gap between the spiral membrane element and the pressure vessel due to the total filtration, fluid does not accumulate in the gap between the spiral membrane element and the pressure vessel. . Therefore, even when used for separating a fluid containing an organic substance, problems such as propagation of various germs such as microorganisms, generation of offensive odor due to decomposition of the organic substance, and decomposition of the separation membrane do not occur, and high reliability can be obtained.

Further, a stock solution is supplied from at least the outer peripheral side of the spiral type membrane element, and pressure is applied to the spiral type membrane element from all directions and a pressure which causes displacement in the axial direction is not applied. The envelope-shaped membrane wound around the empty tube does not deform into a bamboo shoot. This eliminates the need for a packing holder and an exterior material, thereby reducing parts costs and manufacturing costs. In addition, since the whole amount is filtered, a high recovery rate can be obtained without using a large pump for supplying the stock solution. Thereby, the system cost is reduced.

Further, since pressure is applied to the spiral membrane element from all directions, the spiral membrane element does not deform even if the supply pressure of the stock solution is increased. Therefore, high pressure resistance can be obtained.

Further, a permeating liquid may be used as the cleaning liquid. The method for cleaning a spiral-type membrane element according to the second invention is a spiral-type membrane element comprising a plurality of independent or continuous envelope-shaped membranes wound around the outer peripheral surface of a perforated hollow tube via a stock solution flow path material. The method for cleaning a spiral-type membrane element in which the outer peripheral portion of the spiral membrane element is covered with a liquid permeable material, and the outer peripheral surface side of the liquid permeable material is wholly or partially covered with an outer peripheral channel material. Then, after removing the permeate by filtration, a cleaning liquid is introduced from at least one open end of the perforated hollow tube, and the cleaning liquid derived from the outer peripheral surface of the perforated hollow tube is passed through at least the outer periphery of the spiral membrane element. The ratio of the amount of the permeating liquid permeating through the envelope membrane during filtration to the amount of the permeating liquid permeating through the envelope membrane during washing is set to 600 or less.

In the above-mentioned spiral type membrane element, since at least the outer peripheral portion is open without being covered with the exterior material, the undiluted solution is supplied from at least the outer peripheral portion side of the spiral type membrane element and the whole amount is filtered. be able to. In this case, contaminants are trapped at least at the outer periphery of the spiral-wound membrane element.

When washing liquid is introduced from at least one open end of the perforated hollow tube at the time of washing, the washing liquid derived from the outer peripheral surface of the perforated hollow tube passes through the envelope-like membrane and flows into the undiluted liquid flow path material. It flows along and is discharged from at least the outer peripheral portion of the spiral membrane element. Thereby, the contaminants trapped at least at the outer peripheral portion of the spiral membrane element are separated from the spiral membrane element and discharged out of the system together with the cleaning liquid. Therefore, the contaminants trapped at least on the outer peripheral portion of the spiral-type membrane element can be uniformly removed.

Further, by setting the ratio of the amount of the permeated liquid permeating the envelope-shaped membrane during filtration to the amount of the cleaning liquid permeated through the envelope-shaped membrane during cleaning to 600 or less, an excessive load is applied to the spiral-type membrane element. In addition to preventing the separation membrane from being applied, the contaminants adhered to the outer peripheral portion are removed by performing sufficient washing, and stable operation with high filtration efficiency can be continuously performed for a long period of time.

Here, the flow rate of the permeated liquid during filtration is 0.5 m^Three
/ M^Two2.0m / day or more^Three/ M^Two/ Day or less
Supply the undiluted solution and set the filtration time at
Minutes or less, the flow rate of the cleaning liquid during cleaning is 1.0 m^Three/
m^Two4.0m / day or more^Three/ M ^TwoYes to be less than / day
The washing liquid is introduced into the hollow tube and the washing time is reduced to 10 hours.
It is preferable that the time is not less than seconds and not more than 300 seconds.

In particular, the permeate flow rate during filtration is 0.5 m ³ /
When the stock solution is supplied so as to be not less than m ² / day and not more than 2.0 m ³ / m ² / day, and when the filtration time is not less than 10 minutes and not more than 30 minutes, the flow rate of the washing liquid at the time of washing is 1.0 m ³ / m. ^Two
/ Day to 3.0 m ³ / m ² / day The washing solution is introduced into the perforated hollow tube, the washing time is 30 seconds to 60 seconds, and the permeate that has passed through the envelope membrane during filtration. More preferably, the ratio of the amount of the cleaning liquid permeating the envelope-shaped membrane during cleaning to 120 or less.

Thus, the contaminants adhering to the outer peripheral portion can be sufficiently removed, and a stable operation can be performed continuously for a long period of time, and a decrease in filtration efficiency can be suppressed.

A method for operating a spiral membrane module according to a third invention is a method for operating a spiral membrane module in which one or a plurality of spiral membrane elements are housed in a pressure vessel having a stock solution inlet, The spiral membrane element includes a spiral membrane element in which a plurality of independent or continuous envelope membranes are wound around the outer peripheral surface of a perforated hollow tube via a stock solution flow path material, and the outer periphery of the spiral membrane element Portion is covered with a liquid permeable material, the outer peripheral surface side of the liquid permeable material is wholly or partially covered with an outer peripheral channel material, and at the time of operation, at least the outer peripheral portion of the spiral membrane element is passed through the raw liquid inlet of the pressure vessel. The undiluted solution is supplied from the side, the permeate is taken out from at least one open end of the perforated hollow tube, and the washing liquid is introduced from at least one open end of the perforated hollow tube during washing. The washing liquid discharged from the outer peripheral surface of the perforated hollow tube is discharged from at least the outer peripheral portion of the spiral membrane element and taken out of the pressure vessel from the raw liquid inlet, and the permeated liquid permeating the envelope-shaped membrane during the operation period And the ratio of the amount of the cleaning liquid permeating the envelope-shaped membrane during the cleaning period to 600 or less.

According to the spiral membrane module operating method of the present invention, during the operation, the stock solution is supplied from at least the outer peripheral side of the spiral membrane element, and the whole is filtered. In this case, contaminants are trapped at least at the outer periphery of the spiral-wound membrane element.

When the cleaning liquid is introduced from at least one open end of the perforated hollow tube, the cleaning liquid derived from the outer peripheral surface of the perforated hollow tube flows through the envelope-like membrane and flows along the stock solution flow path material. Is discharged from at least the outer peripheral portion of the spiral membrane element. Thereby, the contaminants trapped at least at the outer peripheral portion of the spiral membrane element are separated from the spiral membrane element. Since the spiral membrane element is prevented from spreading between the envelopes at the outer periphery by the liquid permeable material and the outer peripheral passage material, the contaminants adhered to at least the outer periphery of the spiral membrane element during backwashing. A flow path for discharging the gas out of the system is secured. For this reason, the separated contaminants are discharged out of the system together with the cleaning liquid. Therefore, it is possible to uniformly remove at least the contaminants trapped on at least the outer peripheral portion of the spiral-wound membrane element, and it is possible to maintain a constant amount of permeate during operation.

Further, by setting the ratio of the amount of the permeated liquid permeating the envelope-shaped membrane during the operation period to the amount of the cleaning liquid permeated through the envelope-shaped membrane during the cleaning period to be 600 or less, an excessively large amount of the spiral type membrane element can be obtained. In addition to preventing the load from being applied to the separation membrane, sufficient washing is performed to remove contaminants attached to the outer peripheral portion, and stable operation with high filtration efficiency can be continuously performed for a long time.

Here, the flow rate of the permeated liquid during filtration is 0.5 m ³
/ M ² / day or more and 2.0 m ³ / m ² / day or less, and a filtration time of 10 minutes or more and 300 minutes or less.
Minutes or less. The cleaning liquid is introduced into the perforated hollow tube so that the flow rate of the cleaning liquid at the time of cleaning is 1.0 m ³ / m ² / day or more and 4.0 m ³ / m ² / day or less, and the cleaning time is 10 seconds or more. More preferably, the time is 300 seconds or less. Within such a range, the permeate flow rate during filtration so that the ratio of the amount of the permeate that has permeated through the envelope membrane during the operation period and the amount of the permeate that has permeated the envelope membrane during the cleaning period is 600 or less, Set the filtration time, the flow rate of the cleaning solution and the cleaning time.

In particular, the flow rate of the permeated liquid during filtration is 0.5 m ³ /
More preferably, the stock solution is supplied so as to be at least m ² / day and at most 2.0 m ³ / m ² / day, and the filtration time is at least 10 minutes and at most 30 minutes. In addition, the cleaning liquid is introduced into the perforated hollow tube so that the flow rate of the cleaning liquid at the time of cleaning is 1.0 m ³ / m ² / day or more and 3.0 m ³ / m ² / day or less, and the cleaning time is 30 seconds or more. More preferably, the time is 60 seconds or less. In this case, the ratio of the amount of the permeating liquid that has passed through the envelope membrane during the operation period to the amount of the cleaning liquid that has passed through the envelope membrane during the cleaning period is 120 or less.

By setting the permeate flow rate and the filtration time during filtration as described above, it is possible to prevent an excessive load from being applied to the separation membrane, to suppress the accumulation of contaminants on the outer periphery, and to achieve a stable operation. The operation can be continuously performed for a long time. In addition, it is possible to efficiently obtain a target permeated water amount. In this case, the ratio of the amount of the permeating liquid that has passed through the envelope membrane during the operation period to the amount of the cleaning liquid that has passed through the envelope membrane during the cleaning period is 120 or less.

Further, by setting the flow rate of the cleaning liquid and the cleaning time during the cleaning as described above, the contaminants adhering to the outer peripheral portion can be sufficiently peeled off, and a stable operation can be continuously performed for a long time. At the same time, it is possible to suppress a decrease in filtration efficiency.

Further, no dead space is formed in the gap between the spiral membrane element and the pressure vessel due to the total filtration, so that no fluid remains in the gap between the spiral membrane element and the pressure vessel. . Therefore, even when used for separating a fluid containing an organic substance, problems such as propagation of various germs such as microorganisms, generation of offensive odor due to decomposition of the organic substance, and decomposition of the separation membrane do not occur, and high reliability can be obtained.

Further, since a stock solution is supplied from at least the outer peripheral side of the spiral membrane element, pressure is applied to the spiral membrane element from all directions, and no pressure which causes displacement in the axial direction is applied. The envelope-shaped membrane wound around the empty tube does not deform into a bamboo shoot. This eliminates the need for a packing holder and an exterior material, thereby reducing parts costs and manufacturing costs. In addition, since the whole amount is filtered, a high recovery rate can be obtained without using a large pump for supplying the stock solution. Thereby, the system cost is reduced.

Further, since pressure is applied to the spiral membrane element from all directions, the spiral membrane element does not deform even if the supply pressure of the stock solution is increased. Therefore, high pressure resistance can be obtained.

A method for cleaning a spiral-type membrane module according to a fourth aspect of the present invention is a method for cleaning a spiral-type membrane module in which one or more spiral-type membrane elements are housed in a pressure vessel. Includes a spiral membrane element in which a plurality of independent or continuous envelope membranes are wound around the outer peripheral surface of a perforated hollow tube via a raw liquid flow path material, and the outer peripheral portion of the spiral membrane element is liquid permeable. The outer peripheral surface side of the liquid permeable material is entirely or partially covered with the outer peripheral channel material, and after extracting the permeated liquid by filtration, from at least one open end of the perforated hollow tube A cleaning liquid is introduced, and the cleaning liquid derived from the outer peripheral surface of the perforated hollow tube is discharged from at least the outer peripheral part of the spiral membrane element and taken out of the pressure vessel.
The ratio of the amount of the permeated liquid permeating the envelope-shaped membrane during filtration to the amount of the cleaning liquid permeated through the envelope-shaped membrane during washing is set to 600 or less.

In the above spiral type membrane module, since at least the outer peripheral portion of the spiral type membrane element is open without being covered with the exterior material, the stock solution is supplied from at least the outer peripheral side of the spiral type membrane element. , Total filtration can be performed. In this case, contaminants are trapped at least at the outer periphery of the spiral-wound membrane element.

When the cleaning liquid is introduced from at least one opening end of the perforated hollow tube during cleaning, the cleaning liquid derived from the outer peripheral surface of the perforated hollow tube permeates the envelope-like membrane and flows into the stock solution flow path material. It flows along and is discharged from at least the outer peripheral portion of the spiral membrane element. Thereby, the contaminants trapped at least at the outer peripheral portion of the spiral membrane element are separated from the spiral membrane element and discharged out of the system together with the cleaning liquid. Therefore, the contaminants trapped at least on the outer peripheral portion of the spiral-type membrane element can be uniformly removed.

Further, by setting the ratio of the amount of the permeating liquid permeating through the envelope membrane during filtration to the amount of the cleaning liquid permeating through the envelope membrane during washing to be 600 or less, an excessive load is applied to the spiral membrane element. In addition to preventing the contact with the separation membrane, sufficient washing is performed to remove contaminants adhering to the outer peripheral portion, and stable operation with high filtration efficiency can be continuously performed for a long time.

Here, the flow rate of the permeated liquid during filtration is 0.5 m^Three
/ M^Two2.0m / day or more^Three/ M^Two/ Day or less
Supply the undiluted solution and set the filtration time at
Minutes or less, the flow rate of the cleaning liquid during cleaning is 1.0 m^Three/
m^Two4.0m / day or more^Three/ M ^TwoYes to be less than / day
The washing liquid is introduced into the hollow tube and the washing time is reduced to 10 hours.
It is preferable that the time is not less than seconds and not more than 300 seconds.

In particular, the flow rate of the permeate during filtration is 0.5 m ³ /
When the stock solution is supplied so as to be not less than m ² / day and not more than 2.0 m ³ / m ² / day, and when the filtration time is not less than 10 minutes and not more than 30 minutes, the flow rate of the washing liquid at the time of washing is 1.0 m ³ / m. ^Two
/ Day to 3.0 m ³ / m ² / day The washing solution is introduced into the perforated hollow tube, the washing time is 30 seconds to 60 seconds, and the permeate that has passed through the envelope membrane during filtration. More preferably, the ratio of the amount of the cleaning liquid permeating the envelope-shaped membrane during cleaning to 120 or less.

As a result, the contaminants adhering to the outer peripheral portion can be sufficiently peeled off, stable operation can be performed continuously for a long time, and a decrease in filtration efficiency can be suppressed.

[0058]

FIG. 1 is a partially cutaway perspective view of a spiral membrane element according to an embodiment of the present invention. FIG. 2 is a cross-sectional view showing an example of the envelope-shaped membrane of the spiral membrane element shown in FIG. 1, and FIG. 3 is a cross-sectional view showing another example of the envelope-shaped membrane of the spiral membrane element shown in FIG. is there.

The spiral type membrane element 1 shown in FIG.
Includes a spiral-shaped membrane element 1a formed by winding a plurality of independent envelope-shaped membranes 3 or a plurality of continuous envelope-shaped membranes 3 on the outer peripheral surface of a water collecting pipe 2 composed of a perforated hollow pipe. . Raw water spacers (raw liquid flow path material) between the envelope films 3 to prevent the envelope films 3 from adhering to each other and to reduce the film area, and to form a flow path for raw water.
4 has been inserted.

The outer peripheral surface of the spiral membrane element 1a is covered with a separation membrane 9 which is a liquid permeable material. As the separation membrane 9, a microfiltration membrane or an ultrafiltration membrane is used.

As the microfiltration membrane, a polymer organic membrane such as polyolefin, polysulfone, polypropylene, polyethylene, polystyrene, polyacrylonitrile, cellulose acetate and the like can be used. As the ultrafiltration membrane, polysulfone, polypropylene, polystyrene,
A high molecular organic film such as polyacrylonitrile, cellulose acetate, or polyethylene can be used.

The outer peripheral surface of the separation membrane 9 is covered with an outer peripheral channel material 5 made of a net. As the material of the net,
Polymer materials such as polyolefin, polysulfone, polypropylene, polyethylene, polystyrene, polyacrylonitrile, and cellulose acetate; inorganic materials such as ceramic;
Metal, synthetic rubber, fiber, or the like can be used.

The pore size of the microfiltration membrane is 0.01 μm or more and 1
It is preferably 0 μm or less. The pore size of the ultrafiltration membrane is preferably from 20,000 to 0.01 μm. Further, it is preferable that the net used as the outer peripheral channel material 5 has a mesh size of 4 mesh or more and 100 mesh or less.

The pore size of the microfiltration membrane or the ultrafiltration membrane used as the separation membrane 9 and the number of meshes of the net used as the outer peripheral channel material 5 are selected according to the quality of the raw water.

In the spiral membrane element 1 shown in FIG. 1, a microfiltration membrane having a pore diameter of 0.4 μm and made of polyolefin such as ethylene vinyl alcohol is used as the separation membrane 9. Further, an ultrafiltration membrane made of polysulfone may be used as the separation membrane 9. Further, a 50 mesh net made of PET (polyethylene terephthalate) is used as the outer peripheral channel material 5.

Note that, in addition to the outer peripheral surface of the spiral membrane element 1a, the end face of the spiral membrane element 1a may be covered with the separation membrane 9.

As shown in FIG. 2 and FIG.
Is formed by superposing two separation membranes 7 on both sides of a permeated water spacer (permeated liquid flow path material) 6 and bonding three sides thereof, and the opening of the envelope-shaped membrane 3 is formed on the outer periphery of the water collecting pipe 2. Attached to the surface. 10 kgf / c for the separation membrane 7
Low pressure reverse osmosis membranes, ultrafiltration membranes, microfiltration membranes, etc., operated at m ² or less are used.

In the example of FIG. 2, a plurality of envelope-shaped membranes 3 are formed by independent separation membranes 7, respectively. In the example of FIG.
A plurality of envelope membranes 3 are formed by folding a continuous separation membrane 7.

If the thickness of the raw water spacer 4 is larger than 0.5 mm, it becomes difficult to capture contaminants in the raw water at least at the outer peripheral portion of the spiral membrane element 1. On the other hand, when the thickness of the raw water spacer 4 is smaller than 0.1 mm, the envelope films 3 are likely to come into contact with each other, and the film area is reduced.
Therefore, the thickness of the raw water spacer 4 is preferably 0.1 mm or more and 0.5 mm or less.

As shown in FIG. 1, the outer peripheral flow path member 5 is formed in a lattice shape so that a plurality of wires 61 and 62 cross each other at right angles. The thickness of the wire 61 is set to be larger than the thickness of the wire 62. This makes it easier for the raw water 51 to flow between the wires 61 almost linearly in a direction parallel to the wires 61.

Further, as shown in FIG.
Are arranged such that the wire 61 is parallel to the axial direction of the water collecting pipe 2. Therefore, the raw water is the spiral membrane element 1
It becomes easy to flow in the axial direction at the outer peripheral portion of a.

When the thickness t of the outer peripheral flow path member 5 is larger than 30 mm, the volume efficiency of the spiral membrane element 1 with respect to the pressure vessel storing the spiral membrane element 1 becomes small. On the other hand, the thickness t of the outer peripheral channel material 5 is 0.6 m.
If it is smaller than m, the flow rate of raw water for discharging contaminants attached to at least the outer peripheral portion of the spiral membrane element 1 during backflow cleaning of permeated water is reduced. Therefore, the thickness of the outer peripheral channel material 5 is 0.6 mm or more and 30 m or more.
m or less.

The porosity in the thickness direction of the outer peripheral flow path member 5 is set to, for example, 20% or more and 60% or less. Thereby, sufficient strength of the outer peripheral channel member 5 can be secured while reducing the resistance of the raw water that moves the contaminant in the axial direction during the backwashing. The vertical and horizontal pitches of the mesh of the outer peripheral channel member 5 are, for example, 3 mm or more and 30 mm or less.
Thus, the raw water can be sufficiently supplied between the envelope-shaped membranes 3 while preventing the outer peripheral surface of the spiral membrane element 1a from contacting the pressure vessel and narrowing the flow path of the raw water.

The whole of the outer peripheral separation membrane 9 may be covered with the outer peripheral channel material 5, or a part of the area may be covered with the outer peripheral channel material 5.

FIG. 4 is a cross-sectional view showing an example of a method for operating the spiral membrane element and the spiral membrane module according to the present invention. As shown in FIG. 4, the pressure vessel (pressure-resistant vessel) 10 includes a cylindrical case 11 and a pair of end plates 12.
a, 12b. A raw water inlet 13 is formed on one end plate 12a, and a raw water outlet 15 is formed on the other end plate 12b. A permeated water outlet 14 is provided at the center of the other end plate 12b.

The spiral type membrane element 1 is housed in a cylindrical case 11, and both open ends of the cylindrical case 11 are sealed by end plates 12a and 12b, respectively. One end of the water collecting pipe 2 is fitted to the permeated water outlet 14 of the end plate 12b, and an end cap 16 is attached to the other end. Thus, a spiral type membrane module is configured. A pipe 19 is connected to the raw water inlet 13 of the end plate 12a, and a pipe 20 is further connected to the pipe 19. The pipes 19 and 20 have valves 18a, 1 respectively.
8b are provided. A pipe 17 is connected to the raw water outlet 15 of the end plate 12b. The pipe 18 has a valve 18c
Is provided.

During operation of the spiral type membrane element 1, the valve 18a of the pipe 19 is opened, and the valve 18b of the pipe 20 and the valve 18c of the pipe 17 are closed. Piping 1
Through 9, raw water 51 is introduced into the pressure vessel 10 from the raw water inlet 13 of the pressure vessel 10. The raw water 51 flows along the outer peripheral channel material 5, passes through the separation membrane 9 from at least the outer peripheral side of the spiral membrane element 1, and penetrates between the envelope-shaped membranes 3 along the raw water spacer 4. In the example of FIG.
Raw water 51 enters between the envelope-shaped membranes 3 from the outer peripheral side and both end sides of the spiral membrane element 1. The permeated water that has passed through the separation membrane 7 flows into the water collecting pipe 2 along the permeated water spacer 6. Thereby, the permeated water 52 is taken out from the permeated water outlet 14 of the pressure vessel 10. In this way,
Complete filtration is performed.

In this case, since the outer peripheral surface of the spiral membrane element 1 a is covered with the separation membrane 9, contaminants such as turbid substances larger than the pore diameter of the separation membrane 9 are removed from at least the outer periphery of the spiral membrane element 1. Caught in the department. That is,
Only contaminants smaller than the pore size of the separation membrane 9
Penetrate in between. Therefore, the load on the separation membrane 7 constituting the envelope-shaped membrane 3 is reduced.

Here, the flow rate of the permeated water is 2.0 m ³ / m ² /
When the filtration time exceeds 300 days, or when the filtration time exceeds 300 minutes, the load of the separation membrane 9 on the outer peripheral portion of the spiral membrane element 1 and the separation membrane 7 constituting the envelope-shaped membrane 3 increases, and the separation membrane 9 increases. Raw water 5 captured in
The contaminants in 1 increase and deposit on the separation membrane 9. This makes it difficult to perform stable operation continuously for a long period of time.

On the other hand, when the permeate flow rate is less than 0.5 m ³ / m ² / day, or when the filtration time is less than 10 minutes, the load on the separation membranes 7 and 9 of the spiral membrane element 1 decreases. . However, since filtration efficiency is low and the amount of permeated water obtained is reduced, large-scale equipment is required to obtain the desired amount of permeated water.

From the above, the permeated water flow rate is 0.5 to
It is preferable to supply the raw water 51 to the spiral membrane element 1 so as to have a flow rate of 2.0 m ³ / m ² / day.
The filtration time is preferably set to 10 to 300 minutes. As a result, an excessive load is prevented from being applied to the separation membranes 7 and 9, and the deposition of contaminants on the separation membrane 9 is suppressed.
Stable operation can be continuously performed for a long period of time.
In addition, it is possible to efficiently obtain a target permeated water amount.

The raw water 54 may be partially taken out from the raw water outlet 15 by opening the valve 18 c of the pipe 17. In this case, the flow of raw water can be formed at the outer peripheral portion of the spiral membrane element 1. As a result, a part of the contaminants is reduced while the sedimentation of the contaminants in the raw water is suppressed.
Can be discharged outside.

After filtration for a certain period of time, backwashing with permeated water 52 is performed from the permeate side. FIG. 5 is a partially cutaway perspective view showing the backwashing operation in the spiral membrane element 1 of FIG. At the time of backwashing, the valve 1
The permeated water 52 is introduced into the water collection pipe 2 from the permeated water outlet 14 in FIG. 4 with the valve 8a and the valve 18c of the pipe 17 closed and the valve 18b of the pipe 20 opened. The permeated water 52 at the time of backwashing passes through the envelope-shaped membrane 3 from the water collecting pipe 2, peels off contaminants on the membrane surface, and flows along the raw water spacer 4 at least toward the outer peripheral portion. Further, the contaminants trapped on at least the outer peripheral portion of the spiral membrane element 1 are easily separated by the permeated water 52. After that, flushing with raw water is performed. That is, with the valve 18 a of the pipe 19 opened and the valve 18 b of the pipe 20 closed, the valve 18 c of the pipe 17 is opened while the raw water 51 is supplied from the raw water inlet 13 through the pipe 19. As a result, the raw water 51 flows linearly in the axial direction along the outer peripheral flow path material 5, the separated contaminants are discharged out of the system through the raw water outlet 15 and the pipe 17 in FIG. Contaminants remaining on the outer periphery of the membrane element 1 are separated from the spiral membrane element 1. As a result, the membrane flux is remarkably recovered compared to before the backwashing. In addition, raw water 5 containing pollutants discharged out of the system by flushing
4 may be returned to the stock solution tank storing the stock water.

As described above, in the operation method of the spiral membrane element 1, the above-mentioned filtration operation and backwashing are alternately repeated.

According to the above-described cleaning method, the contaminants adhering to the outer peripheral portion of the spiral membrane element 1, particularly the separation membrane 9, can be easily and reliably discharged out of the system along the outer peripheral channel member 5. Therefore, an increase in resistance of the separation film 9 can be suppressed. Thereby, a stable amount of permeated water can always be maintained.

Here, when the backwashing time is less than 10 seconds, or when the permeated water flow rate during the backwashing is less than 1 m ³ / m ² / day, the membrane surface and the outer peripheral portion of the spiral membrane element 1 are removed. It is difficult to sufficiently remove the contaminants attached to the surface, and the contaminants accumulate on the film surface and the outer peripheral portion. This makes it difficult to perform stable operation continuously for a long period of time.

On the other hand, when the backwashing time exceeds 300 seconds, or when the permeated water flow rate during backwashing is 4 m ³ / m ² /
In the case of exceeding the number of days, the contaminants adhering to the membrane surface and the outer peripheral portion of the spiral membrane element 1 can be sufficiently removed, but the permeated water 52 obtained by the filtration can be removed.
Is used as a large amount of washing water, so that the amount of permeated water obtained decreases as a whole, and the filtration efficiency decreases.

From the above, the backwashing time is 10 to
The flow rate is preferably 300 seconds, and the flow rate of the permeated water during backwashing is preferably 1 to 4 m ³ / m ² / day. Thereby, the contaminants adhering to the membrane surface and the outer peripheral portion of the spiral membrane element 1 are sufficiently peeled off, and a stable operation can be continuously performed for a long period of time, and a decrease in filtration efficiency is suppressed. Becomes possible.

Here, in the above operating method, the amount of water passing through the filter (the permeated water 52 permeating through the envelope-shaped membrane 3 during the operation period)
Quantity) so that the ratio V ₁ / V ₂ between V ₁ and the amount of permeated water 52 passing through the envelope-like membrane 3 through water (washing period during back washing) V ₂ is 600 or less, the range of the Within, the flow rate of the permeated water during filtration, the filtration time, the flow rate of the permeated water during backwashing, and the time for backwashing are set. This prevents an excessive load from being applied to the separation membranes 7 and 9, and performs sufficient washing to remove contaminants adhering to the membrane surface and the outer peripheral portion, thereby ensuring stable operation with high filtration efficiency for a long time. It is possible to continue.

In particular, the flow rate of permeated water during filtration is 0.5 to 2.
More preferably, the raw water 51 is supplied so as to be 0 m ³ / m ² / day, and the filtration time is 10 to 30 minutes. Also, the flow rate of the permeated water during backwashing is 1.0 to 3.0 m.
More preferably, the permeated water 52 is introduced into the water collecting pipe 2 so that the flow rate becomes ³ / m ² / day, and the time for the backwashing is set to 30 to 60 seconds. In this case, the ratio V ₁ / V ₂ between passing water V ₁ of the filtration and passing water V ₂ at the time of backwashing is 120 or less. Thus, when the ratio V ₁ / V ₂ between passing water V ₁ of the filtration and passing water V ₂ at the time of back washing is 120 or less,
This is more preferable because stable operation with higher filtration efficiency can be continuously performed for a long period of time.

For example, in the above operation method, the supply pressure of the raw water 51 is adjusted so that a permeated water flow rate of 2.0 m ³ / m ² / day is obtained at the time of filtration, filtration is performed for 30 minutes, and then backwashing is performed. The backflow cleaning is performed for 30 seconds by adjusting the supply pressure of the permeated water 52 so that the permeated water flow rate at this time is 1 m ³ / m ² / day. In this case, the ratio V ₁ / V ₂ between passing water V ₁ of the filtration and passing water V ₂ at the time of back washing is 120. In this case, the recovery rate of the permeated water 52 is 99.2%, and the filtration efficiency is high. In addition, since the load on the separation membranes 7 and 9 can be reduced and the contaminants attached to the membrane surface and the outer peripheral portion can be sufficiently removed, stable operation can be continuously performed for a long time. Become.

Further, since the spiral membrane element 1 is covered at its outer periphery with the outer peripheral passage material 5, handling (handling) is improved.

Further, since the dead space such as the dead space S shown in FIG. 16 is not formed in the gap between the spiral membrane element 1 and the pressure vessel 10 by the above-mentioned filtration mode, various bacteria such as microorganisms can be formed. There is no problem of odor propagation, generation of offensive odor due to decomposition of organic matter, decomposition of separation membrane, etc., and high reliability can be obtained.

Further, since pressure is applied to the spiral membrane element 1 from all directions, the spiral membrane element 1
No deformation problem occurs, and the packing holder and the exterior material become unnecessary. Thereby, component costs and manufacturing costs are reduced.

Further, since the whole amount is filtered, the raw water 51
It is not necessary to use a large pump for supplying oil. Thereby, the system cost is reduced.

In the backwashing described above, first, the permeated water 52 is introduced into the water collecting pipe 2 and trapped on the membrane surface and the outer peripheral portion of the spiral membrane element by the permeated water 52 derived from the outer peripheral surface of the water collecting pipe 2. Although the flushing with the raw water is performed after the contaminants thus separated are removed, the flushing with the raw water may be performed first, and then the permeated water 52 may be introduced into the water collecting pipe 2. According to this cleaning method, most of the contaminants trapped on the outer peripheral portion of the spiral membrane element 1 are removed by flushing, and the permeated water 52 is further introduced, whereby the membrane surface and the outer peripheral portion of the spiral membrane element 1 are introduced. Contaminants remaining in the wastewater can be removed. Therefore, also in this case, the same effect as the above-described backwashing can be obtained.

Alternatively, flushing with raw water may be performed constantly or periodically in parallel with the introduction of the permeated water 52 into the water collecting pipe 2. Also in this case, the same effect as the above-described backwashing can be obtained.

FIG. 6 is a front view of a spiral membrane element according to another embodiment of the present invention. In FIG. 6, the illustration of the outer peripheral channel material is omitted.

The spiral type membrane element 1 shown in FIG.
In, both ends of the spiral membrane element 1a are sealed with a resin layer 40. In the spiral membrane element 1 shown in FIG. 6B, one end of the spiral membrane element 1a is sealed with a resin layer 40.

In the spiral membrane element 1 shown in FIGS. 6A and 6B, the number of working steps in manufacturing increases, but the space for supplying raw water to both ends or one end of the spiral membrane element 1 is unnecessary. Become. Therefore, the pressure vessel can be miniaturized, and the spiral membrane module in which the spiral membrane element 1 is housed in the pressure vessel can be miniaturized.

By arranging the end portion of the spiral membrane element 1 sealed with the resin layer 19 on the raw water inlet side of the pressure vessel, the end face of the spiral membrane element 1 is introduced by the dynamic pressure of the raw water when the raw water is introduced. Dirt can be prevented from adhering.

FIG. 7 is a partially cutaway perspective view of a spiral-type membrane element according to still another embodiment of the present invention. FIG. 8 is a cross-sectional view showing an example of the envelope-shaped membrane of the spiral membrane element shown in FIG. 7, and FIG. 9 is a cross-sectional view showing another example of the envelope-shaped membrane of the spiral membrane element shown in FIG. is there. FIG. 10 is a partially cutaway front view of the spiral membrane element of FIG.

The spiral type membrane element 1 shown in FIG.
Includes a spiral-shaped membrane element 1a formed by winding a plurality of independent envelope-shaped membranes 3 or a plurality of continuous envelope-shaped membranes 3 on the outer peripheral surface of a water collecting pipe 2 composed of a perforated hollow pipe. . Raw water spacers (raw liquid flow path material) between the envelope films 3 to prevent the envelope films 3 from adhering to each other and to reduce the film area, and to form a flow path for raw water.
4 has been inserted.

As shown in FIG. 8 and FIG.
Is formed by superposing two separation membranes 7 on both sides of a permeated water spacer (permeated liquid flow path material) 6 and bonding three sides thereof, and the opening of the envelope-shaped membrane 3 is formed on the outer periphery of the water collecting pipe 2. Attached to the surface. 10 kgf / c for the separation membrane 7
Low pressure reverse osmosis membranes, ultrafiltration membranes, microfiltration membranes, etc., operated at m ² or less are used.

In the example of FIG. 8, a plurality of envelope-shaped membranes 3 are formed by independent separation membranes 7, respectively. In the example of FIG.
A plurality of envelope membranes 3 are formed by folding a continuous separation membrane 7.

Further, the outer peripheral surface of the spiral membrane element 1a is covered with a net 8 which is a liquid permeable material. As a material of the net 8, a synthetic resin such as polyolefin, polysulfone, polypropylene, polyester, polyethylene, polystyrene, polyacrylonitrile, or polyamide, or a metal such as stainless steel or iron can be used.

It is preferable that the net 8 has a size of 3 mesh or more and 200 mesh or less. Thereby, the swelling of the spiral membrane element 1a due to the back pressure at the time of backwashing can be reliably suppressed, and the raw water can be sufficiently supplied into the spiral membrane element 1a from the outer peripheral side during operation.

In the spiral type separation membrane element 1 shown in FIG. 7, the net 8 is made of tricot cloth impregnated with epoxy resin. The net 8 is 50 mesh, the pitch of the warp and the weft is 0.5 mm, and the diameter of the warp and the weft is 0.15 mm.

The end face of the spiral membrane element 1a may be covered with the net 8 in addition to the outer peripheral face of the spiral membrane element 1a.

As shown in FIG. 10, a resin 81 is applied at equal intervals along the circumferential direction to three places of the net 8 covering the outer peripheral surface of the spiral membrane element 1a. It is fixed to the outer peripheral surface of 1a at three places. The number of locations where the resin 81 is applied is not particularly limited since it depends on the back pressure generated during backwashing. However, if the number of locations where the resin 81 is applied is greater than three, contamination of the outer peripheral portion of the spiral membrane element 1a during backflow cleaning is made. Substances are less likely to be removed. Therefore, for example, in a spiral membrane element 1a having a length of 944 cm, it is preferable to fix about three places with the resin 5a.

The outer peripheral surface of the net 8 is covered with the outer peripheral channel material 5. The material and dimensions of the outer peripheral channel member 5 are the same as those of the outer peripheral channel member 5 shown in FIG.

Note that the entire outer peripheral net 8 may be covered with the outer peripheral flow path member 5, or a partial area may be covered with the outer peripheral flow path member 5.

Spiral type membrane element 1 shown in FIG.
Is operated by the operation method of the spiral type membrane element shown in FIG. During operation of the spiral membrane element 1, the valve 18a of the pipe 19 is opened, and the valve 18b of the pipe 20 and the valve 18c of the pipe 19 are closed. Through the pipe 19, the raw water 51 is supplied to the raw water inlet 13 of the pressure vessel 10.
From the pressure vessel 10. The raw water 51 flows along the outer peripheral channel material 5, and the spiral membrane element 1
From the outer peripheral side and both end sides of the envelope-shaped film 3. The permeated water that has passed through the separation membrane 7 flows into the water collecting pipe 2 along the permeated water spacer 6. Thereby, the permeated water 52 is taken out from the permeated water outlet 14 of the pressure vessel 10.
In this way, total filtration is performed.

In this case, since the outer peripheral surface of the spiral membrane element 1 a is covered with the net 8, contaminants such as turbid substances larger than the pore diameter of the net 8 are contaminated at least at the outer peripheral section of the spiral membrane element 1. Be captured. That is,
Only contaminants smaller than the pore size of the net 8 are enveloped membrane 3
Penetrate in between. Therefore, the load on the separation membrane 7 constituting the envelope-shaped membrane 3 is reduced.

Here, the flow rate of the permeated water is 2.0 m ³ / m ² /
When the filtration time exceeds 300 days, or when the filtration time exceeds 300 minutes, the load of the separation membrane 9 on the outer peripheral portion of the spiral membrane element 1 and the separation membrane 7 constituting the envelope-shaped membrane 3 increases, and the separation membrane 9 increases. Raw water 5 captured in
The contaminants in 1 increase and deposit on the separation membrane 9. This makes it difficult to perform stable operation continuously for a long period of time.

On the other hand, when the permeate flow rate is less than 0.5 m ³ / m ² / day or when the filtration time is less than 10 minutes, the load on the separation membranes 7 and 9 of the spiral membrane element 1 decreases. However, since filtration efficiency is low and the amount of permeated water obtained is reduced, large-scale equipment is required to obtain the desired amount of permeated water.

From the above, the flow rate of the permeated water is 0.5 to
It is preferable to supply the raw water 51 to the spiral membrane element 1 so as to have a flow rate of 2.0 m ³ / m ² / day.
The filtration time is preferably set to 10 to 300 minutes. As a result, an excessive load is prevented from being applied to the separation membranes 7 and 9, and the deposition of contaminants on the separation membrane 9 is suppressed.
Stable operation can be continuously performed for a long period of time.
In addition, it is possible to efficiently obtain a target permeated water amount.

The raw water 54 may be partially removed from the raw water outlet 15 by opening the valve 18c of the pipe 17. In this case, the flow of raw water can be formed at the outer peripheral portion of the spiral membrane element 1. As a result, a part of the contaminants is reduced while the sedimentation of the contaminants in the raw water is suppressed.
Can be discharged outside.

After filtering for a certain period of time, backwashing shown in FIG. 5 is performed. At the time of backwashing, the valve 18a of the pipe 19 is
In a state where the valve 18c of the pipe 17 is closed and the valve 18b of the pipe 20 is opened, the permeated water 52 is introduced from the permeated water outlet 14 of FIG. The permeated water 52 at the time of the backwashing passes through the envelope-shaped membrane 3 from the water collecting pipe 2, peels off the contaminants on the membrane surface from the membrane surface, and flows along the raw water spacer 4 at least toward the outer peripheral portion. In addition, this permeated water 5
Due to 2, the contaminants captured on at least the outer peripheral portion of the spiral membrane element 1 are easily peeled off. afterwards,
Flush with raw water. That is, with the valve 18 a of the pipe 19 opened and the valve 18 b of the pipe 20 closed, the valve 18 c of the pipe 17 is opened while the raw water 51 is supplied from the raw water inlet 13 through the pipe 19. As a result, the raw water flows linearly in the axial direction along the outer peripheral flow path material 5, the separated contaminants are discharged out of the system through the raw water outlet 15 and the pipe 17 in FIG. Contaminants remaining on the outer peripheral portion of the element are peeled off from the spiral membrane element 1. As a result, the membrane flux is remarkably recovered compared to before the backwashing. The raw water 54 containing the pollutants discharged out of the system by the flushing
May be returned to the stock solution tank storing the stock water.

As described above, in the operation method of the spiral type membrane element 1, the above-mentioned filtration operation and backwashing are alternately repeated.

According to the above-described cleaning method, contaminants adhering to the outer peripheral portion of the spiral type membrane element 1, particularly the net 8, can be easily and reliably discharged out of the system along the outer peripheral portion flow path member 5. Therefore, it is possible to suppress an increase in the resistance of the net 8. Thereby, a stable amount of permeated water can always be maintained.

Here, when the backwashing time is less than 10 seconds, or when the flow rate of the permeated water during the backwashing is less than 1 m ³ / m ² / day, the membrane surface and the outer peripheral portion of the spiral type membrane element 1 are removed. It is difficult to sufficiently remove the contaminants attached to the surface, and the contaminants accumulate on the film surface and the outer peripheral portion. This makes it difficult to perform stable operation continuously for a long period of time.

On the other hand, when the backwash time exceeds 300 seconds, or when the permeate flow rate during backwash is 4 m ³ / m ² /
In the case of exceeding the number of days, the contaminants adhering to the membrane surface and the outer peripheral portion of the spiral membrane element 1 can be sufficiently removed, but the permeated water 52 obtained by the filtration can be removed.
Is used as a large amount of washing water, so that the amount of permeated water obtained decreases as a whole, and the filtration efficiency decreases.

From the above, the backwashing time is 10 to
The flow rate is preferably 300 seconds, and the flow rate of the permeated water during backwashing is preferably 1 to 4 m ³ / m ² / day. Thereby, the contaminants adhering to the membrane surface and the outer peripheral portion of the spiral membrane element 1 are sufficiently peeled off, and a stable operation can be continuously performed for a long period of time, and a decrease in filtration efficiency is suppressed. Becomes possible.

[0125] Here, in the above method of operation, the ratio V ₁ / V of the passing water amount V ₁ of the filtration and passing water V ₂ at the time of back washing
Within the above range, so that ₂ is 600 or less,
The flow rate of permeated water during filtration, the filtration time, the flow rate of permeated water during backwashing, and the time for backwashing are set. This prevents an excessive load from being applied to the separation membranes 7, 9, and
Sufficient washing is performed to remove contaminants attached to the membrane surface and the outer peripheral portion, and stable operation with high filtration efficiency can be continuously performed for a long period of time.

In particular, the flow rate of permeated water during filtration is 0.5 to 2.
More preferably, the raw water 51 is supplied so as to be 0 m ³ / m ² / day, and the filtration time is 10 to 30 minutes. Also, the flow rate of the permeated water during backwashing is 1.0 to 3.0 m.
More preferably, the permeated water 52 is introduced into the water collecting pipe 2 so that the flow rate becomes ³ / m ² / day, and the time for the backwashing is set to 30 to 60 seconds. In this case, the ratio V ₁ / V ₂ between passing water V ₁ of the filtration and passing water V ₂ at the time of backwashing is 120 or less. Thus, when the ratio V ₁ / V ₂ between passing water V ₁ of the filtration and passing water V ₂ at the time of back washing is 120 or less,
This is more preferable because stable operation with higher filtration efficiency can be continuously performed for a long period of time.

For example, in the above-described operation method, the supply pressure of the raw water 51 is adjusted so that a permeate flow rate of 2.0 m ³ / m ² / day is obtained at the time of filtration, filtration is performed for 30 minutes, and then backwashing is performed. The backflow cleaning is performed for 30 seconds by adjusting the supply pressure of the permeated water 52 so that the permeated water flow rate at this time is 1 m ³ / m ² / day. In this case, the ratio V ₁ / V ₂ between passing water V ₁ of the filtration and passing water V ₂ at the time of back washing is 120. In this case, the recovery rate of the permeated water 52 is 99.2%, and the filtration efficiency is high. In addition, since the load on the separation membranes 7 and 9 can be reduced and the contaminants attached to the membrane surface and the outer peripheral portion can be sufficiently removed, stable operation can be continuously performed for a long time. Become.

Further, since the spiral membrane element 1 is covered at its outer periphery with the outer peripheral passage material 5, handling (handling) is improved.

In the spiral membrane element 1 shown in FIG. 7, the outer surface of the spiral membrane element 1a is
Even if the back pressure generated during backwashing by the contaminants trapped on the outer periphery of the spiral membrane element 1a increases, the spiral membrane element 1a is prevented from bulging by the net 8 on the outer periphery. The distance between the envelope films 3 does not increase. Therefore, damage to the membrane due to the bulging of the envelope membrane 3 is prevented, and contaminants in the raw water 51 do not leak into the permeated water 52.

In particular, since the net 8 is fixed to the outer peripheral portion of the spiral membrane element 1a at a plurality of locations, the spiral membrane element 1a is reliably prevented from bulging even when the back pressure during backwashing is high. .

Furthermore, since no dead space is formed in the gap between the spiral membrane element 1 and the pressure vessel, problems such as the propagation of microorganisms and other germs, the generation of offensive odors due to the decomposition of organic substances, and the decomposition of separation membranes are caused. It does not occur and high reliability is obtained.

Also, since pressure is applied to the spiral membrane element 1 from all directions, the spiral membrane element 1
No deformation problem occurs, and the packing holder and the exterior material become unnecessary. Thereby, component costs and manufacturing costs are reduced.

Further, since the whole amount is filtered, the raw water 51
It is not necessary to use a large pump for supplying oil. Thereby, the system cost is reduced.

In the backwashing, the permeated water 52 is first introduced into the water collecting pipe 2 and trapped on the membrane surface and the outer peripheral portion of the spiral type membrane element by the permeated water 52 derived from the outer peripheral surface of the water collecting pipe 2. Although the flushing with the raw water is performed after exfoliating the contaminated material and the pollutant trapped on the membrane surface, the flushing with the raw water is performed first, and then the permeated water 52 may be introduced into the water collecting pipe 2. . According to this cleaning method, most of the contaminants trapped on the outer peripheral portion of the spiral membrane element 1 and the contaminants trapped on the membrane surface are removed by flushing,
Further, by introducing permeated water, contaminants remaining on the membrane surface and the outer peripheral portion of the spiral membrane element 1 can be removed. Therefore, also in this case, the same effect as the above-described backwashing can be obtained.

Alternatively, flushing with raw water may be performed constantly or periodically in parallel with the introduction of the permeated water 52 into the water collecting pipe 2. Also in this case, the same effect as the above-described backwashing can be obtained.

Further, the operating method of the spiral membrane element according to the present invention may be applied to the spiral membrane element 1 using a part of the permeated water spacer 6 as a net as shown in FIG. In such a spiral membrane element 1, the permeated water spacer 6 inserted into one envelope-shaped membrane 3 is extended so as to protrude to the outside from the outer peripheral side of the envelope-shaped membrane 3. The extended portion of the spacer 6 forms a net 8 as a spiral membrane element 1a.
Is wound on the outer peripheral surface of. The space between the permeate spacer 6 projecting from the outer peripheral side of the envelope-shaped membrane 3 to the outside and the envelope-shaped membrane 3 is sealed with a resin 6a.

In this case, the swelling of the spiral membrane element 1a due to the back pressure at the time of backwashing can be prevented by the extended permeated water spacer 6 while suppressing the cost of additional parts due to the separate provision of the net 8.

In the above description, the spiral type membrane module in which one spiral type membrane element 1 is loaded in the pressure vessel 10 as shown in FIG. 4 has been described. However, the spiral type membrane element according to the present invention is described. The operation method of the spiral membrane module can also be applied to a spiral membrane module in which a plurality of spiral membrane elements 1 are loaded in a pressure vessel.

FIG. 13 is a schematic sectional view showing another example of the method of operating the spiral membrane element and the spiral membrane module according to the present invention.

As shown in FIG. 13, the pressure vessel 100
A cylindrical case 111 and a pair of end plates 120a, 120b
It consists of. A raw water inlet 130 is formed at the bottom of the cylindrical case 111, and a raw water outlet 131 is formed at the top. The raw water outlet 131 is also used for air release. Further, a permeated water outlet 140 is provided at the center of the end plates 120a and 120b.

A plurality of spiral membrane elements 1 in which the water collecting pipes 2 are connected in series by the interconnector 116 are accommodated in a cylindrical case 111, and both open ends of the cylindrical case 111 are connected to end plates 120a and 120b, respectively. Sealed. Water collecting pipe 2 of spiral type membrane element 1 at both ends
Are connected to the end plates 12 through the adapter 115, respectively.
0a and 120b are fitted to the permeated water outlet 140. Thus, a spiral-type membrane module in which the plurality of spiral-type membrane elements 1 are loaded in the pressure vessel 100 is configured.

During operation of the spiral membrane module,
The raw water outlet 131 is closed, and the raw water inlet 13 of the pressure vessel 100 is closed.
From 0, the raw water 51 is introduced into the pressure vessel 100. The raw water 51 flows along the outer peripheral channel material 5 of each spiral membrane element 1. In each spiral membrane element 1, the raw water 51 penetrates the separation membrane 9 at least from the outer peripheral side, and penetrates between the envelope-shaped membranes 3 along the raw water spacer 4. The permeated water that has passed through the separation membrane 7 flows into the water collection pipe 2 along the permeated water spacer 6, and the permeated water 52 is taken out from the permeated water outlets 140 at both ends of the pressure vessel 100.
In this way, total filtration is performed. In this case as well, a part of the raw water may be taken out from the raw water outlet 131 in the same manner as in the operation method of the spiral membrane element and the spiral membrane module shown in FIG.

After filtration for a certain period of time, backwashing with permeated water 52 is performed from the permeate side. For backwashing, permeated water 52 is introduced into the water collecting pipe 2 of the spiral membrane element 1 from the permeated water outlets 140 at both ends of the pressure vessel 100.
In each spiral membrane element 1, the permeated water 52 passes through the envelope-shaped membrane 3 from the water collecting pipe 2, peels off contaminants on the membrane surface from the membrane surface, and flows along the raw water spacer 4 at least toward the outer peripheral portion. Further, the contaminants trapped at least at the outer peripheral portion of each spiral membrane element 1 are easily separated by the permeated water 52. Then, Raw Water Exit 1
At the same time as the opening 31, the raw water 51 is supplied from the raw water inlet 130 to perform flushing, and the separated contaminants are discharged from the raw water outlet 131 to the outside of the spiral membrane module together with the raw water. In this case, as in the operation method of the spiral membrane element and the spiral membrane module shown in FIG. 4, flushing with raw water may be performed before backwashing, or raw water may be used in parallel with backwashing. Flushing may be performed.

According to the operation method of the spiral type membrane element and the spiral type membrane module as described above, similar to the operation method of the spiral type membrane element and the spiral type membrane module shown in FIG. It is supplied from at least the outer peripheral side of the membrane element 1, and is subjected to total filtration in each spiral membrane element 1. In this case, in each spiral membrane element 1, contaminants are captured at least at the outer peripheral portion. Therefore, the load on the separation membrane 7 constituting the envelope-shaped membrane 3 is reduced.

Further, at the time of washing, the contaminants adhering to the separation membrane 7 and the outer peripheral portion of each spiral type membrane element 1 can be easily discharged out of the system along the outer peripheral flow path member 5, so that a stable operation can be achieved. The amount of permeated water can be maintained.
Further, since the spiral membrane module is loaded with a plurality of spiral membrane elements 1, the processing capacity of the spiral membrane module is large and the permeated water 52 can be obtained efficiently.

[0146] Further, since the dead space is not formed in the space between each spiral type membrane element 1 and the pressure vessel 100 by the above-mentioned filtration mode, the propagation of various germs such as microorganisms and the generation of offensive odor due to the decomposition of organic matter are prevented. No problems such as generation and decomposition of the separation membrane occur, and high reliability can be obtained.

Further, since pressure is applied to all the spiral membrane elements 1 from all directions, the problem of deformation of the spiral membrane elements 1 does not occur, and the packing holder and the exterior material are not required. Thereby, component costs and manufacturing costs are reduced.

Further, since the whole amount is filtered, the raw water 51
It is not necessary to use a large pump for supplying oil. Thereby, the system cost is reduced.

Also in this example, the flow rate of the permeated water of each spiral membrane element 1 is 0.5 to 2.0 m ³ / m ² / similar to the operation method of the spiral membrane element and the spiral membrane module shown in FIG. Raw water 51 to become the day
, And the filtration time is 10-3.
Preferably, the time is 00 minutes. This prevents an excessive load from being applied to the separation membranes 7 and 9, suppresses the accumulation of contaminants on the separation membrane 9, and enables a stable operation to be performed for a long time. In addition, it is possible to efficiently obtain a target permeated water amount.

The backwashing time is preferably 10 to 300 seconds, and the flow rate of the permeated water of each spiral membrane element 1 during backwashing is 1.0 to 4.0 m ³ / m ^2.
/ Day is preferred. Thereby, the contaminants adhering to the membrane surface and the outer peripheral portion of the spiral membrane element 1 are sufficiently peeled off, and a stable operation can be continuously performed for a long period of time, and a decrease in filtration efficiency is suppressed. Becomes possible.

[0151] Here, in the operation method of the spiral wound membrane module, it is preferable the passing water amount V ₁ of the filtration, the ratio V ₁ / V ₂ between passing water V ₂ at the time of back washing is 600 or less . As a result, an excessive load is applied to the separation membranes 7, 9
In addition to preventing the occurrence of contamination, sufficient cleaning is performed to remove contaminants attached to the membrane surface and the outer peripheral portion, and stable operation with high filtration efficiency can be continuously performed for a long period of time.

In particular, the flow rate of the permeated water at the time of filtration is 0.5 to 2.
More preferably, the raw water 51 is supplied so as to be 0 m ³ / m ² / day, and the filtration time is 10 to 30 minutes. Also, the flow rate of the permeated water during backwashing is 1.0 to 3.0 m.
More preferably, the permeated water 52 is introduced into the water collecting pipe 2 so that the flow rate becomes ³ / m ² / day, and the time for the backwashing is set to 30 to 60 seconds. In this case, the ratio V ₁ / V ₂ between passing water V ₁ of the filtration and passing water V ₂ at the time of backwashing is 120 or less. Thus, when the ratio V ₁ / V ₂ between passing water V ₁ of the filtration and passing water V ₂ at the time of back washing is 120 or less,
This is more preferable because stable operation with higher filtration efficiency can be continuously performed for a long period of time.

[0153]

[Example 1] In Example 1, a spiral type membrane element 1 (R by Nitto Denko Corporation) shown in FIG.
Operation was performed using S30-S4).

As raw water 51, industrial water (pH 6-8, water temperature 10-30 ° C.) was used. 2.0m ³ / m ² during washing
/ Day of permeate flow rate
Filtration was performed for 30 minutes by the operation method shown in FIG. Thereafter, backwashing shown in FIG. 5 was performed. In this example, the backwash time was set to 30 seconds, and the supply pressure was adjusted so that the flow rate of the permeated water during the backwash was 1.0 m ³ / m ² / day. After the permeated water 52 was introduced into the water collecting pipe 2, flushing with the raw water 51 was performed for 20 seconds.

The spiral membrane element 1 was operated continuously for 40 days while performing the above-mentioned filtration and backwashing, and the transmembrane pressure of the spiral membrane element 1 was measured 40 days after the start of the operation. .

Example 2 In Example 2, filtration and backwashing were performed by the same operation method as in Example 1 except for the following points, and the spiral membrane element 1 after 40 days from the start of operation was cleaned. The transmembrane pressure was measured.

In this embodiment, the backwashing time is set to 3
0 seconds, and the flow rate of permeated water during backwashing is 2.0 m ³ / m
^The supply pressure was adjusted to be ² / day.

[Example 3] In Example 3, filtration and backwashing were performed in the same manner as in Example 1 except for the following points, and the membrane of the spiral type membrane element 1 40 days after the start of operation was used. The pressure difference between them was measured.

In this embodiment, 1.0 m ³
The supply pressure was adjusted so that a permeate flow rate of / m ² / day was obtained, and filtration was performed for 20 minutes. The backwashing time was 30 seconds, and the flow rate of the permeated water during the backwashing was 2.0 m ³ /
The supply pressure was adjusted to be m ² / day.

[Comparative Example 1] In Comparative Example 1, filtration and backwashing were performed by the same operating method as in Example 1 except for the following points, and the spiral membrane element 1 after 40 days from the start of operation was removed. The transmembrane pressure was measured.

In this comparative example, 3.0 m ³
The filtration was performed for 300 minutes while adjusting the supply pressure so as to obtain a permeate flow rate of / m ² / day. The backwashing time was 60 seconds, and the flow rate of the permeated water during the backwashing was 1.0 m ^3.
/ M ² / day was adjusted to supply pressure.

[Comparative Example 2] In Comparative Example 2, filtration and backwashing were performed by the same operating method as in Example 1 except for the following points, and the spiral membrane element 1 after 40 days from the start of operation was cleaned. The transmembrane pressure was measured.

In this comparative example, the backwashing time was set at 5 times.
Seconds, and the flow rate of the permeated water during backwashing is 1.0 m ³ / m ²
/ Day.

Table 1 shows the measurement results in Examples 1 to 3 and Comparative Examples 1 and 2.

[0165]

[Table 1]

[0166] As shown in Examples 1-3, the ratio V ₁ / V ₂ between passing water V ₁ of the filtration and passing water V ₂ at the time of back washing is 6
In the case of 00 or less, the load on the separation membranes 7 and 9 is reduced, and the contaminants attached to the membrane surface and the net 8 can be reliably removed. . Thereby, stable operation with high filtration efficiency can be continuously performed for a long period of time. Particularly, in the case V ₁ / V ₂ is 120 or less as in Examples 1 to 3, it is possible to perform for a long time continue a more stable operation.

On the other hand, as shown in Comparative Examples 1 and 2, V
_{When 1} / V ₂ exceeds 600, that is, in Comparative Example 1 in which the load on the separation membranes 7 and 9 is large due to excessive water flow V ₁ during filtration, and sufficient reverse flow because water flow V ₂ is small during back flow washing. In Comparative Example 2 in which cleaning was not performed, a contaminant was deposited on the film surface and the net 8, so that the pressure difference between the films was increased, and it was difficult to perform stable operation for a long time.

[Brief description of the drawings]

FIG. 1 is a partially cutaway perspective view of a spiral membrane element according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing an example of an envelope-shaped membrane of the spiral membrane element shown in FIG.

FIG. 3 is a cross-sectional view showing another example of the envelope-shaped membrane of the spiral membrane element shown in FIG.

FIG. 4 is a cross-sectional view showing an example of a method of operating the spiral membrane element of FIG.

FIG. 5 is a partially cutaway perspective view showing a backwashing operation in the spiral membrane element of FIG. 1;

FIG. 6 is a front view of a spiral membrane element according to another embodiment of the present invention.

FIG. 7 is a partially cutaway perspective view of a spiral-type membrane element according to still another embodiment of the present invention.

8 is a cross-sectional view showing an example of an envelope-shaped membrane of the spiral membrane element shown in FIG.

FIG. 9 is a cross-sectional view showing another example of the envelope-shaped membrane of the spiral membrane element of FIG. 7;

FIG. 10 is a partially cutaway front view of the spiral membrane element of FIG. 7;

FIG. 11 is a partially cutaway perspective view showing a backwash operation in the spiral membrane element of FIG. 7;

FIG. 12 is a cross-sectional view showing an example in which a permeated water spacer is used as a net.

FIG. 13 is a schematic cross-sectional view showing another example of the method of operating the spiral membrane element and the spiral membrane module according to the present invention.

FIG. 14 is a partially cutaway perspective view of a conventional spiral-type membrane element.

FIG. 15 is an external perspective view of a conventional spiral type membrane element.

FIG. 16 is a cross-sectional view illustrating an example of a conventional method of operating a spiral-type membrane element.

FIG. 17 is a partially cutaway perspective view showing a backwash operation in a conventional spiral membrane element.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Spiral type membrane element 1a Spiral type membrane element 2 Water collecting pipe 3 Envelope type membrane 4 Raw water spacer 5 Peripheral flow path material 6 Permeated water spacer 7 Separation membrane 8 Net 9 Separation membrane 10, 100 Pressure vessel 13, 130 Raw water inlet 14, 140 Permeate outlet 51 Raw water 52 Permeate 61,62 Wire rod 81 Resin

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Hajime Hisada 1-1-2 Shimohozumi, Ibaraki-shi, Osaka Nitto Denko Corporation F-term (reference) 4D006 GA05 GA06 GA07 HA61 HA62 HA65 JA05B JA06A JA06B JA06C JA30A JA30B JA30C KC02 KC03 KC12 KC13 KE01Q KE05Q KE06P KE07P KE12P KE15P KE16P KE22Q KE24Q KE28Q KE30R MA03 MA22 MB05 MC18 MC22 MC23 MC24 MC39 MC62 PA01 PB04 PB24

Claims (5)

[Claims] 1. A method for operating a spiral-type membrane element, wherein the spiral-type membrane element is formed by winding a plurality of independent or continuous envelope-shaped membranes on an outer peripheral surface of a perforated hollow tube via a stock solution flow path material. A spirally wound spiral membrane element, an outer peripheral portion of the spiral membrane element is covered with a liquid permeable material, and an outer peripheral surface side of the liquid permeable material is wholly or partially covered with an outer peripheral channel material. During operation, a stock solution is supplied from at least the outer peripheral side of the spiral membrane element, and a permeate is taken out from at least one open end of the perforated hollow tube. A cleaning liquid is introduced from one open end, and the cleaning liquid derived from the outer peripheral surface of the perforated hollow tube is discharged from at least the outer peripheral part of the spiral-type membrane element, and permeates the envelope-shaped membrane during an operation period. A ratio of the amount of the permeated liquid to the amount of the cleaning liquid permeated through the envelope-shaped membrane during the cleaning period is set to 600 or less. 2. The method for operating a spiral type membrane element according to claim 1, wherein the cleaning liquid is a permeate. 3. A method for cleaning a spiral-type membrane element, wherein the spiral-type membrane element is formed by winding a plurality of independent or continuous envelope-shaped membranes on an outer peripheral surface of a perforated hollow tube via a stock solution flow path material. A spirally wound spiral membrane element, an outer peripheral portion of the spiral membrane element is covered with a liquid permeable material, and an outer peripheral surface side of the liquid permeable material is wholly or partially covered with an outer peripheral channel material. After removing the permeate by filtration, a washing solution is introduced from at least one open end of the perforated hollow tube, and the washing solution derived from the outer peripheral surface of the perforated hollow tube is passed through the spiral membrane element. Spiral type, wherein the ratio between the amount of the permeated liquid permeated through the envelope-shaped membrane at the time of filtration and the amount of the cleaning liquid permeated through the envelope-shaped membrane at the time of washing is 600 or less. film Element cleaning method. 4. A method for operating a spiral membrane module comprising one or a plurality of spiral membrane elements housed in a pressure vessel having a stock solution inlet, wherein the spiral membrane element is a hollow hollow tube. A plurality of envelope-like membranes that are independent or continuous on the outer peripheral surface include a spiral membrane element wound around a raw liquid flow path material, and the outer peripheral portion of the spiral membrane element is covered with a liquid permeable material, The outer peripheral surface side of the liquid permeable material is wholly or partially covered with an outer peripheral channel material, and during operation, supplies a raw liquid from at least the outer peripheral side of the spiral membrane element through the raw liquid inlet of the pressure vessel, The permeate is taken out from at least one open end of the perforated hollow tube, and at the time of washing, a washing liquid is introduced from at least one open end of the perforated hollow tube,
The cleaning liquid derived from the outer peripheral surface of the perforated hollow tube is discharged from at least the outer peripheral portion of the spiral membrane element, and is taken out of the pressure vessel from the stock solution inlet,
A method of operating a spiral-type membrane module, wherein a ratio of an amount of the permeated liquid permeating the envelope-shaped membrane during an operation period to an amount of the cleaning liquid permeated through the envelope-shaped membrane during a cleaning period is 600 or less. . 5. A method for cleaning a spiral-wound membrane module comprising one or a plurality of spiral-wound membrane elements housed in a pressure vessel, wherein the spiral-wound membrane element is independent of an outer peripheral surface of a perforated hollow tube. Or a spiral membrane element formed by winding a plurality of continuous envelope membranes via a stock solution flow path material, and an outer peripheral portion of the spiral membrane element is covered with a liquid permeable material, After the outer peripheral surface side is wholly or partially covered with the outer peripheral channel material and the permeate is taken out by filtration, a washing liquid is introduced from at least one open end of the perforated hollow tube, and The cleaning liquid derived from the outer peripheral surface of the empty tube is discharged from at least the outer peripheral portion of the spiral membrane element and taken out of the pressure vessel, and the amount of the permeated liquid that has passed through the envelope membrane at the time of filtration and the amount of the cleaning liquid are washed. A method for cleaning a spiral-type membrane module, wherein the ratio of the amount of the cleaning liquid permeating the envelope-shaped membrane during cleaning is 600 or less.