JP2007181822A - Water treatment system for producing drinking water and its operation method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a water treatment system for producing drinking water by which an MF (microfiltration) membrane or a UF (ultrafiltration) membrane is hardly clogged even if the raw water of fresh water is directly treated by an MF membrane separator or a UF membrane separator, and which is compact so as to be mounted on a high mobility vehicle and can stably produce drinking water over a long period. <P>SOLUTION: The raw water of fresh water is directly treated by the MF membrane separator or the UF membrane separator without using a long fiber filter large in its installation space. Then, a plurality of modules in the MF membrane separator or UF membrane separator are frequently backwashed part by part, thus the clogging of the MF membrane or UF membrane is prevented. Further, the process that the treated water in the MF membrane separator or UF membrane separator is stored in a tank and is used for the backwashing is not adopted, but, high pressure concentrated water in an RO membrane separator which is ordinarily drained as it is is used as washing water for the backwashing in the MF membrane separator or UF membrane separator without interposing a water storage tank and a pump. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention uses river water, lake water, etc. as raw water, and membrane separation using a microfiltration membrane (MF membrane) separation device or ultrafiltration membrane (UF membrane) separation device and a reverse osmosis membrane (RO membrane) device. The present invention relates to a water treatment system for performing treatment and producing drinking water and an operation method thereof.

  Since the MF membrane or UF membrane has high removal performance of fine particles and the like, it is used as a solid-liquid separation means for separating fine solids, suspended substances, microorganisms and the like contained in raw water. In addition, the MF membrane separation device incorporating the MF membrane or the UF membrane separation device incorporating the UF membrane is easy to operate, and is widely used in the fields of medicine, chemistry, semiconductors, and the like in industry. .

  RO membranes can remove salt, organic substances (trihalomethane, agricultural chemicals, etc.) and fine particles (viable bacteria, dead bacteria, viruses, etc.) in water stably and vigorously. It is used in a wide range. For example, in the fields of pharmaceuticals and semiconductors, it is used for the production of water for injection, ultrapure water, and the like.

  Since the RO membrane has very fine pores, raw water (for example, industrial water) is first pretreated using an MF membrane separation device or a UF membrane separation device, and the treated water is supplied to the RO membrane. It is common to perform membrane separation treatment with an apparatus.

  Here, in order to produce drinking water at the time of disasters such as earthquakes and tsunamis, an in-vehicle mobile water purification device using a long hair filtration device and a diatomaceous earth filtration device is disclosed in Patent Document 1 as a purification device for purifying raw water in the affected area. It is disclosed.

  Further, Patent Document 2 discloses a vehicle-mounted fresh water production apparatus including a seawater desalination apparatus using an RO membrane and a contaminated fresh water purification device using a UF membrane.

  A mobile water purification facility comprising a first filter that performs filtration through a rotating filter cylinder, a second filter that performs MF membrane or RO membrane treatment, and a third filter that obtains pure water using the RO membrane. However, this is disclosed in Patent Document 3.

This Patent Document 3 also discloses that the concentrated water of the RO membrane device is used as the cleaning water for backwashing of the MF membrane separation device or the UF membrane separation device while using the backwashing blower together.
Japanese Utility Model Publication No. 62-9997 JP-A-9-141262 JP-A-8-71567

  However, the mobile water purifier disclosed in Patent Literature 1 cannot remove chemical substances such as bacteria, viruses, salts, heavy metals, and agricultural chemicals, and when the turbidity of raw water is high, a diatomaceous earth filter Has had the disadvantage of having to be manually backwashed frequently.

  Moreover, since the mobile water purification equipment disclosed in Patent Literature 2 and Patent Literature 3 includes a raw water tank or a tank for storing raw water added with a flocculant, it is difficult to mount the water purification equipment unless it is a large vehicle. is there.

  Furthermore, Patent Document 3 discloses that the concentrated water of the RO membrane device is used as the washing water for backwashing of the MF membrane separation device or the UF membrane separation device, but there is no disclosure about the operation method therefor. If the concentrated water of the RO membrane separator is simply used as the backwash water, the amount of treated water naturally decreases at the time of backwashing.

  On the other hand, roads etc. are depressed in areas affected by earthquakes, etc., or there are obstacles such as debris on the roads, and there are places where large vehicles such as conventional trucks cannot run. In such a case, since it becomes impossible to supply purified water in the stricken area, the use of a small vehicle called a high mobility vehicle that is small and highly mobile that can travel even on some rough roads has been studied.

  However, the size of the carrier bed of the high mobility vehicle is about 2070 mm long × 2000 mm wide × 1175 mm high, and compared to the size of a general large vehicle carrier 4500 mm long × 2990 mm wide × 2080 mm high, the space for water purification equipment It is a big problem that is very limited. In addition, because the loading weight is small, it was necessary to make the water treatment system more compact, lighter, and more energy efficient in consideration of the specifications (power generation capacity, size, weight) of the generator mounted on the high mobility vehicle. . In addition, maintainability of water purification equipment was also an issue.

  In order to remove bacteria, viruses, chemical substances, etc. contained in the raw water, it is necessary to use the RO membrane device. However, as described above, the raw water is treated with the MF membrane separator or UF membrane separator as a pretreatment. Must. Here, if raw water is directly processed by the MF membrane separation device or UF membrane separation device without using a long hair filter or the like having a large installation space, the drinking water production system can be miniaturized, but if the raw water turbidity is high, the MF Since the membrane or the UF membrane is easily clogged, it becomes difficult to produce drinking water that is stable for a long period of time.

  In addition, since the treated water of the MF membrane separation device or the UF membrane separation device is used as the washing water for back washing of the MF membrane module, the conventional water treatment system has a storage tank for MF membrane treated water or UF membrane treated water, and A pump for backwashing was necessary, and it was difficult to install in a high mobility vehicle.

  Furthermore, when drinking water is produced in a disaster area, it is expected that the amount of water produced is always constant, and it is preferable that the amount of water produced by the water treatment system decreases even during the cleaning of the MF membrane separator or UF membrane separator. There are also circumstances that do not exist.

  The present invention is such that even if raw fresh water is directly processed by an MF membrane separator or UF membrane separator, the MF membrane or UF membrane is not easily clogged, and is small enough to be mounted on a high mobility vehicle. It aims at providing the drinking water manufacturing system which can be manufactured stably for a period, and its operating method.

  The water treatment system for drinking water production according to the present invention directly treats raw water with an MF membrane separation device or a UF membrane separation device without using a long hair filter having a large installation space. The first feature is to prevent clogging of the MF membrane or UF membrane by frequently back-washing a plurality of modules of the MF membrane separation device or UF membrane separation device part by part.

  The drinking water production water treatment system of the present invention does not store the treated water of the MF membrane separation device or UF membrane separation device in a tank and use it for backwashing, but it is usually drained as it is. The second feature is that the high-pressure concentrated water of the separation device is used as backwashing water for the MF membrane separation device or UF membrane separation device without using a water storage tank and a pump.

Specifically, the present invention
A membrane separator using an MF membrane or UF membrane composed of a plurality of modules;
RO membrane device,
A drinking water production water treatment system for treating treated water of a membrane separation device with an RO membrane device,
The RO membrane device includes a backwashing path that connects the concentrated water discharge port of the RO membrane device and the permeate outlet side channel of each module of the membrane separation device, and backwashes a part of the module of the membrane separation device. The present invention relates to a drinking water production water treatment system characterized in that the concentrated water is used as washing water without being pressurized by a pump (claim 1).

This drinking water production water treatment system
Downstream of the filtration pump of the raw water supply path for supplying raw water to the membrane separator;
Upstream of the pressure pump of the membrane treated water supply path for supplying the treated water of the membrane separator to the reverse osmosis membrane separator,
The permeate outlet side path of the reverse osmosis membrane separator,
A flow meter is provided for each of the backwash paths,
If the indicated value of the flow meter downstream of the filtration pump is less than the required water supply of the membrane separator, increase the rotation speed of the filtration pump,
If the indicated value of the flow meter upstream of the pressure pump is less than the required amount of treated water of the membrane separator, increase the rotation speed of the pressure pump,
If the indicated value of the flow meter on the permeate outlet side path of the reverse osmosis membrane separator is less than the required treated water amount of the reverse osmosis membrane separator, the flow control valve on the concentrated water outlet side is throttled,
By controlling the flow control valve of the backwash path to open when the indicated value of the flowmeter of the backwash path is less than the target value,
It is preferable to keep the amount of treated water in the reverse osmosis membrane separation device constant during operation (Claim 2).

The present invention also provides:
A membrane separator using a microfiltration membrane or an ultrafiltration membrane composed of a plurality of modules;
A reverse osmosis membrane device;
A backwash path that connects the concentrated water outlet of the reverse osmosis membrane device and the outlet side of each module of the membrane separator,
A method for operating a water treatment system for drinking water production in which treated water of a membrane separator is treated with a reverse osmosis membrane device,
When backwashing a part of the module of the membrane separator, the supply of raw water to the module that is not subject to backwashing is stopped while the supply of raw water to the module that is not subject to backwashing is continued. Get treated water,
The present invention relates to a method for operating a water treatment system for producing drinking water, characterized in that the concentrated water of a reverse osmosis membrane separation device is supplied from the permeate outlet side of a module to be backwashed through a backwash path without being pressurized with a pump (claim) Item 3).

  When backwashing a part of the module of the membrane separation device, it is preferable to increase the amount of permeated water from the module that is not subject to backwashing and keep the amount of treated water of the reverse osmosis membrane separation device constant during operation (claim) Item 4).

  In the water treatment system for drinking water production and the operation method thereof according to the present invention, clogging of the MF membrane or UF membrane of the membrane separation device hardly occurs even if the long hair filtration device is omitted. Further, the MF membrane treated water or UF membrane treated water storage tank and the backwash pump can be omitted, and the installation space can be further reduced.

  Further, by omitting a water storage tank that is open to the atmosphere, contamination of MF membrane treated water or UF membrane treated water by microorganisms or foreign matters is less likely to occur. Furthermore, the amount of drinking water produced does not change during system operation.

  Embodiments of the present invention will be described below with reference to the drawings as appropriate. The present invention is not limited to these.

  An example of a conventional drinking water production system using fresh water as raw water is shown in FIG. In this system, first, raw water is sucked into a path 32 by a pumping pump 31 and subjected to primary treatment by a long hair filter 33 to remove suspended substances in the raw water.

  Next, the treated water of the long hair filter 33 is pressurized (about 0.2 MPa) by the filtration pump 35 installed in the path 34 and supplied to the supply water inlet of the MF membrane separation device 36. A UF membrane separator may be used instead of the MF membrane separator.

  The treated water (permeated water) of the MF membrane separator 36 flows from the permeated water outlet of the MF membrane separator 36 to the path 37 and is stored in the MF membrane treated water tank 42 via the valve 46. Then, the MF membrane treated water stored in the MF membrane treated water tank 42 is pressurized (0.5 MPa to 1.5 MPa) by the pressurizing pump 38 installed in the path 37, and is supplied to the supply water inlet of the RO membrane device 39. Supplied.

  The treated water of the RO membrane device 39 is supplied from the permeate outlet of the RO membrane device 39 via the path 40 as drinking water. At this time, an activated carbon adsorption device or the like may be installed in the path 40. The concentrated water of the RO membrane device 39 is drained outside the system through the drainage path 41.

  When the MF membrane of the MF membrane separation device 36 is backwashed, the valve 43 is opened and the valve 46 is closed, and the treated water in the MF membrane treated water tank 42 is backwashed in the backwash path 44. The air is pressurized by the pump 45 and supplied to the permeate outlet side path of the MF membrane separator 36. The backwash drainage is drained out of the system by opening the drain valve 47 installed in the drainage channel 48.

  Next, an example of the drinking water production system of the present invention using fresh water as raw water is shown in FIG. In this water treatment system, the raw water is first sucked into the path 2 by the pump 1 and further pressurized (about 0.2 MPa) by the filtration pump 3 installed in the path 2. At this time, when the raw water turbidity is high, it is preferable to install a simple filter or the like for removing solids in the raw water before the filtration pump 3.

  The raw water pressurized by the filtration pump 3 is supplied to the two MF membrane separation modules 7a and 7b via the path 5. At this time, the flow rate of the raw water at the outlet of the filtration pump 3 is measured by the membrane module inlet flow meter 4. Although two MF membrane separation modules 7a and 7b constitute one membrane separation device, it is also possible to constitute one membrane separation device with three or more modules. In addition, it is also possible to use a UF membrane separation module in place of the MF membrane separation module to perform the RO membrane treatment of the UF membrane treated water.

  In addition, in the system of FIG. 1, two pumps of the pumping pump 1 and the filtration pump 3 are used until the raw water is supplied to the MF membrane separation modules 7a and 7b, but the output of the pumping pump 1 is sufficient. If larger, the filtration pump 3 can be omitted.

  The treated water (permeated water) of the MF membrane separation module 7a flows from the permeate outlet of the MF membrane separation module 7a to the path 9. And it is pressurized by the pressurization pump 11 installed in the path | route 9 (0.5-1.5 MPa), and is supplied to the supply water inlet of RO membrane apparatus 13. FIG. At this time, the flow rate of the MF membrane treated water supplied to the RO membrane device 13 is measured by the RO supply water flow meter 12. The same applies to the treated water of the MF membrane separation module 7b.

  The treated water (permeated water) of the RO membrane device 13 is supplied as drinking water via the path 14. The flow rate of the RO membrane treated water in the path 14 is measured by the RO permeate flow meter 15. An activated carbon adsorption device or the like may be installed in the path 14.

  The concentrated water of the RO membrane device 13 is drained from the drainage path 16. The drainage path 16 is connected with a backwashing path 18 (branching to 18a and 18b) for supplying RO concentrated water to the permeate outlet side path of the MF membrane separation modules 7a and 7b during backwashing. A backwash water supply valve 19 is installed at a position near the drainage path 16 of the washing path 18.

  Usually, the backwash water amount adjusting valve 20 is opened, and the backwash water supply valve 19 is closed. Then, the RO membrane concentrated water is drained out of the system through the drainage path 16. On the other hand, at the time of reverse cleaning of the MF membrane separation modules 7a and 7b, the backwash water amount adjustment valve 20 is closed and the backwash water supply valve 19 is opened, so that the concentrated water flows through the backwash path 18 to the MF membrane separation modules 7a and 7b. It is supplied to the permeate outlet side path.

  If the pressure of MF treated water supplied to the RO membrane device 13 is 0.5 MPa or higher, the pressure of the concentrated water supplied to the backwashing path 18 will also be 0.2 MPa or higher, so it is necessary to pressurize the concentrated water with a pump. The MF membrane separator can be backwashed with the same pressure.

  In the drinking water production water treatment system of the present invention, the MF membrane separation device is composed of a plurality of MF membrane modules. When there are a plurality of MF membrane modules, the MF membrane modules can be back-washed one by one while producing drinking water. For example, even if the raw water supply to the MF membrane module 7a is stopped, the MF membrane module 7b can be supplied with water, so the MF membrane treated water supplied to the RO membrane device 13 is not lost, and the RO membrane treated water is produced. Is possible. At the same time, since high-pressure concentrated water is drained from the RO membrane device 13, the MF membrane module 7a in which the water supply is stopped can be backwashed using this.

(how to drive)
Here, the operation method of the water treatment system for drinking water production of the present invention will be described. When the system is started, first, the membrane module inlet valves 6a and 6b, the membrane module permeate outlet valves 8a and 8b, and the membrane module drain valves 21a and 21b are opened, and the pumping pump 1 and the filtration pump 3 are sequentially started.

The indicated value of the membrane module inlet flow meter 4 is preferably set to a target value of the required MF supply water amount (required MF treated water amount / recovery rate × 100). For example, when the required MF treated water amount is 5 m ³ / h and the recovery rate is 50%, the required MF supply water amount (target value) is preferably 10 m ³ / h. Here, if the indicated value of the membrane module inlet flow meter 4 is less than the target value of 10 m ³ / h, the number of revolutions of the filtration pump 3 is increased to control the indicated value to be 10 m ³ / h. Further, if the indicated value of the membrane module inlet flow meter 4 exceeds the target value, the number of revolutions is reduced to control the indicated value to 10 m ³ / h to adjust the amount of water supplied to the MF membrane modules 7a and 7b.

The pressure switch 10 at the inlet of the pressurization pump activates the pressurization pump 11 when the pressure of the MF membrane treated water in the path 9 becomes a certain level or more. The indicated value of the RO supply water flow meter 12 is preferably set to a target value of the required MF treated water amount (5 m ³ / h in the above example). Here, if the indicated value of the RO supply water flow meter 12 is less than the target value, the number of revolutions of the pressurizing pump 11 is increased so that the indicated value becomes 5 m ³ / h. Further, if the indicated value of the RO supply water flow meter 12 exceeds the target value, the rotational speed is lowered and the indicated value becomes 5 m ³ / h to adjust the amount of water supplied to the RO membrane device 13.

On the other hand, the indicated value of the RO permeate flow meter 15 is the required RO treatment water amount (equal to the required production water amount in the one-stage RO treatment as in the above embodiment, required MF treatment water amount × RO recovery rate / 100) as the target value. It is preferable to do. The RO recovery rate of the RO membrane device 13 is preferably adjusted to a range of 60% to 90% in the case of fresh water. Here, if the indicated value of the RO permeate flow meter 15 becomes less than the target value, the flow rate control valve 17 is opened and the indicated value is controlled to be 5 m ³ / h. Further, if the indicated value of the RO permeate flow meter 15 exceeds the target value, the flow rate control valve 17 is closed and the indicated value becomes 5 m ³ / h, and the permeated water amount (product water amount) of the RO membrane device 13 is controlled. Adjust.

  Next, an operation when the MF membrane of the MF membrane separation module 7a is back-washed will be described. The backwashing of the MF membrane separation modules 7a and 7b is preferably performed alternately by setting a timer, and the MF membrane separation module that has not been backwashed continues to filter raw water.

  When a back washing instruction is issued from the timer, the membrane module inlet valve 6a, the membrane module permeate outlet valve 8a, and the membrane module drain valve 21a are closed. Further, the membrane module cleaning air inlet valve 22a and the membrane module cleaning air outlet valve 23a are opened. Then, the compressor 24 is activated to send air into the MF membrane module 7a from the path 25a, thereby washing the MF membrane with air. The sent air is exhausted from the membrane module cleaning air outlet valve 23a.

  After performing air cleaning for a certain time, the membrane module cleaning air inlet valve 22a and the membrane module cleaning air outlet valve 23a are closed.

Next, the membrane module drain valve 21a, the backwash water inlet valve 26a and the backwash water supply valve 19 are opened, and the concentrated water of the RO membrane device 13 is passed through the backwash path 18a to the permeate outlet side path of the MF membrane separation module 7a. To supply. At this time, the indicated value of the backwash water flow meter 28 is set to a water amount in which “the permeation flux during backwashing of the MF membrane” becomes “100% to 150% of the permeation flux during normal operation of the MF membrane”. It is preferable to use a value. If the indicated value of the backwash water flow meter 28 is less than a target value (for example, 1 m ³ / h), the back wash water adjustment valve 20 is closed to control the indicated value to be 1 m ³ / h. Further, if the indicated value of the backwash water flow meter 28 exceeds 1 m ³ / h, the back wash water amount is adjusted by opening the back wash water adjustment valve 20 so that the indicated value becomes 1 m ³ / h. To do.

  After the backwashing is completed, the backwash water adjustment valve 20 is fully opened, and the membrane module drain valve 21a, the backwash water inlet valve 26a, and the backwash water supply valve 19 are closed. Then, the membrane module inlet valve 6a, the membrane module outlet valve 8a, and the membrane module drain valve 21a are opened, and the filtration operation of the MF membrane module 7a is resumed.

  The operation when the MF membrane separation module 7a is back-washed has been described above, but the operation when the MF membrane separation module 7b is back-washed is the same. The same operation is performed when back-cleaning a module of a UF membrane separation device constituted by a plurality of UF membrane modules instead of the MF membrane separation device.

(Control of MF membrane separation module inlet flow rate and RO feed water flow rate)
Here, the adjustment of the MF membrane treated water supply water amount to the RO membrane device 13 is performed by controlling the number of revolutions of the pressurizing pump 11 based on the indicated value of the RO feed water flow meter 12. It is assumed that the indicated value of the flow meter 4 is stable. During the filtration operation of the MF membrane separation modules 7a and 7b, the indicated value of the membrane module inlet flow meter 4 is stable.

  However, when one of the MF membrane separation modules 7a or 7b is backwashed, the number of MF membrane separation modules used for filtration is reduced from two to one, so that the pressure balance is lost at the start and end of backwashing. The indicated value of the membrane module inlet flow meter 4 varies. At this time, since the RO membrane device 13 is still in operation, it is necessary to control the flow rate control of the RO supply water flow meter 12 so as not to become unstable even if the indicated value of the membrane module inlet flow meter 4 fluctuates. is there.

  Specifically, by controlling the membrane module inlet flow meter 4 earlier, pressure fluctuations at the start and end of backwashing are reduced, and the control of the RO feed water flow meter 12 is delayed to control the membrane module inlet flow meter. The flow control is stabilized by absorbing the fluctuations in the flow rate.

(Control of RO permeate flow rate and backwash water flow rate)
On the other hand, the permeate flow rate of the RO membrane device 13 is adjusted by controlling the opening degree of the flow rate adjustment valve 17 based on the instruction value of the RO permeate flow meter 15. Further, the MF membrane backwash water amount is adjusted by controlling the opening degree of the backwash water amount adjustment valve 20 based on the indicated value of the backwash water flow meter 28.

  During the filtration operation of the MF membrane separation modules 7a and 7b, there is no problem because the flow control based on the backwash water flow meter 28 is not performed (the backwash water adjustment valve 20 is fully opened), but the MF membrane separation module 7a or 7b On the other hand, at the time of backwashing, the control of the RO permeate flow rate and the backwashing water flow rate affect the counterpart control. For this reason, it is necessary to adjust the control timing and responsiveness of the RO permeate flow rate and the backwash water flow rate so that the mutual flow rate control does not become unstable.

  Specifically, by making the control response of the RO permeate flow meter 15 faster, the fluctuation in the flow rate at the start and end of backwashing is reduced, and the response of the backwash water flow rate meter 28 is made slower and the RO permeation is made. The flow control is stabilized by absorbing fluctuations in the amount of water.

  In the above embodiment, a drinking water production water treatment system suitable for treating fresh water has been described. However, if the permeated water of the RO membrane device 13 is further treated using a low pressure RO membrane device, It can also be applied to seawater. When processing seawater, the RO recovery rate of the RO membrane device 13 for processing MF membrane treated water is preferably 40% to 60%.

  The water treatment system for drinking water production of the present invention is useful as a water treatment system that can be mounted on a vehicle such as a high mobility vehicle that is dispatched to a disaster area or an area that does not have a drinking water supply facility.

It is a flowchart which shows an example of the water treatment system for drinking water manufacture of this invention. It is a flow figure showing an example of the conventional water treatment system for drinking water manufacture.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,31: Pumping pump 2,32: Path | route 3,35: Filtration pump 4: Membrane module inlet flowmeter 5: Path | route 6a, 6b: Membrane module inlet valve 7a, 7b: MF membrane separation module (or UF membrane separation module)
8a, 8b: Membrane module permeate outlet valve 9: Route 10: Pressure switch 11, 38: Pressurization pump 12: RO feed water flow meter 13, 39: RO membrane device 14: Route 15: RO permeate flow meter 16: Drainage path 17: Flow rate adjustment valve 18 (18a, 18b): Backwash path 19: Backwash water supply valve 20: Backwash water amount adjustment valve 21a, 21b: Membrane module drain valve 22a, 22b: Membrane module washing air inlet valve 23a , 23b: Membrane module cleaning air outlet valve 24: Compressor 25a, 25b: Path 26a, 26b: Backwash water inlet valve 33: Long hair filter 34: Path 36: MF membrane module (or UF membrane module)
37, 40: Route 41: Drainage route 42: MF membrane treated water tank 43: Valve 44: Backwash route 45: Backwash pump 47: Drain valve 48: Drain route

Claims (4)

A membrane separator using a microfiltration membrane or an ultrafiltration membrane composed of a plurality of modules;
A reverse osmosis membrane device,
A drinking water production system for treating treated water of a membrane separation device with a reverse osmosis membrane device,
A reverse osmosis passage is provided to connect the concentrated water discharge port of the reverse osmosis membrane device and the permeate outlet side passage of each module of the membrane separation device. A water treatment system for producing drinking water, characterized in that the concentrated water of the membrane separator is used as washing water without being pressurized with a pump. Downstream of the filtration pump of the raw water supply path for supplying raw water to the membrane separator;
Upstream of the pressure pump of the membrane treated water supply path for supplying the treated water of the membrane separator to the reverse osmosis membrane separator,
The permeate outlet side path of the reverse osmosis membrane separator,
A flow meter is provided for each of the backwash paths,
If the indicated value of the flow meter downstream of the filtration pump is less than the required water supply of the membrane separator, increase the rotation speed of the filtration pump,
If the indicated value of the flow meter upstream of the pressure pump is less than the required amount of treated water of the membrane separator, increase the rotation speed of the pressure pump,
If the indicated value of the flow meter on the permeate outlet side path of the reverse osmosis membrane separator is less than the required treated water amount of the reverse osmosis membrane separator, the flow control valve on the concentrated water outlet side is throttled,
By controlling the flow control valve of the backwash path to open when the indicated value of the flowmeter of the backwash path is less than the target value,
The water treatment system for drinking water production according to claim 1, wherein the amount of treated water of the reverse osmosis membrane separation device is kept constant during operation. A membrane separator using a microfiltration membrane or an ultrafiltration membrane composed of a plurality of modules;
A reverse osmosis membrane device;
A backwash path that connects the concentrated water outlet of the reverse osmosis membrane device and the outlet side of each module of the membrane separator,
A method for operating a water treatment system for drinking water production in which treated water of a membrane separator is treated with a reverse osmosis membrane device,
When backwashing a part of the module of the membrane separator, the supply of raw water to the module that is not subject to backwashing is stopped while the supply of raw water to the module that is not subject to backwashing is continued. Get treated water,
A method for operating a water treatment system for drinking water production, characterized in that the concentrated water of a reverse osmosis membrane separation device is supplied from the permeate outlet side of a module to be backwashed through a backwash path without being pressurized with a pump. 4. When backwashing a part of a module of a membrane separation device, the amount of permeated water of a module not subject to backwashing is increased, and the amount of treated water of the reverse osmosis membrane separation device is kept constant during operation. Operation method of the water treatment system for drinking water manufacture as described in 2.

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