JP2001239134A - Method for operating reverse osmosis treatment device, control device therefor and method for making water - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for operating a reverse osmosis treatment device capable of maintaining the high quality of permeating water irrespective of the change in the temperature of raw water and the membrane performance of a reverse osmosis module, and reducing the cost of making water while suppressing the variation in the amount of the permeating water. SOLUTION: The reverse osmosis treatment device obtains permeating water by pressurizing the raw water (marine water) and supplying the same to a plurality of reverse osmosis membrane module-units 2a, 2b-2n. The device is provided with an operation administration/control part which controls the number of operated reverse osmosis membrane module-units depending on the temperature of the raw water and/or the quality of the permeating water. When the temperature of the raw water is elevated, the number of operation is reduced and the operation pressure is raised.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a reverse osmosis treatment apparatus for obtaining permeated water using a reverse osmosis membrane module.
The present invention relates to an operation method of a reverse osmosis treatment apparatus capable of maintaining a high quality of permeated water regardless of a change in raw water temperature and a change in membrane performance, a control apparatus thereof, and a fresh water producing method.

[0002]

[Related background art] Generation of freshwater from seawater / brine,
Alternatively, a reverse osmosis treatment device equipped with a reverse osmosis membrane module is used for generating clean water from river water.
This type of reverse osmosis treatment device basically supplies feed water (sea water) that has been subjected to pretreatment such as sterilization or turbid component removal to a predetermined pressure (for example, 6 .0
MPa) to reverse osmosis membrane module unit 2
And the permeated water (fresh water) permeated by the reverse osmosis action in the reverse osmosis membrane module unit 2 is obtained.

[0003] Incidentally, reverse osmosis membrane module unit 2
For example, as shown in FIG. 7, a plurality of reverse osmosis membrane modules 20 in which a plurality of reverse osmosis membrane elements 10 are connected in series and accommodated in a cylindrical pressure vessel 21 are provided in parallel or in series. . In addition, each reverse osmosis membrane element 10
For example, as shown in FIG. 8, a bag-like reverse osmosis membrane 13 containing a flow path material 12 is spirally wound around a center pipe 11 via a mesh spacer 14, and a brine seal 15 is provided at one end thereof. Having a structure. Each of the reverse osmosis membrane elements 10 applies supply water (seawater) of a predetermined pressure supplied from the brine seal 15 side to the mesh spacer 1.
The permeated water (fresh water) which has been guided between the reverse osmosis membranes 13 through the reverse osmosis 4 and passed through the reverse osmosis membrane 13 by the reverse osmosis action is taken out through the center pipe 11.

[0004] The reverse osmosis membrane module 20 moves between the center pipes 11 of the respective reverse osmosis membrane elements 10 as shown in FIG.
As shown in FIG. 5, the inside of the pressure vessel 21 is partitioned by the brine seal 15 while being sequentially connected via the joint 22. However, one end (the most upstream side) of the center pipe 11 is closed by the product tube cap 16. The supply water (seawater) introduced from the supply water port 23 provided at one end of the pressure vessel 21 is supplied to each reverse osmosis membrane element 10.
In the reverse osmosis membrane 13 to obtain the permeated water in the center pipe 11. The permeated water is taken out from a permeated water port 24 provided on the other end side of the pressure vessel 21 and connected to the center pipe 11. In addition, the remainder of the supply water (seawater) that has not passed through each reverse osmosis membrane 13, that is, concentrated water (seawater)
Is discharged from a discharge port 25 provided on the other end side of the pressure vessel 21.

Incidentally, the reverse osmosis treatment apparatus may be constructed by providing a reverse osmosis membrane module unit 2 in two stages as shown in FIGS. 9 to 11, for example. That is, the example shown in FIG. 9 is referred to as a permeated water two-stage method, in which permeated water that has passed through the first-stage reverse osmosis membrane module 2x is further supplied to the second-stage reverse osmosis membrane module 2y. To obtain the permeated water.

The example shown in FIG. 10 is called a concentrated water two-stage method, and the concentrated water obtained in the first-stage reverse osmosis membrane module 2x is transferred to the second-stage reverse osmosis membrane module 2y. It is configured so as to supply and further obtain the permeated water, thereby increasing the permeated water generation efficiency (water production efficiency). In this case, for example, as shown in FIG. 11, the pump 1y for supplying water to the second-stage reverse osmosis membrane module 2y collects the energy of the concentrated water discharged from the second-stage reverse osmosis membrane module 2y. By using a compressor such as a turbocharger that operates while being operated, the desalination cost can be reduced.

[0007]

When raw water such as seawater is subjected to reverse osmosis treatment using the reverse osmosis treatment apparatus configured as described above, and the permeated water (fresh water) is obtained, the raw water is supplied to the reverse osmosis membrane module 2. Not only does the amount of permeated water change depending on the pressure of the raw water (operating pressure), but also the quality of the water changes. Moreover, the membrane performance of the reverse osmosis membrane module 2 changes depending on the temperature of the raw water, and the permeated water amount changes accordingly.

For this reason, for example, in a reverse osmosis treatment apparatus constructed so as to control the operating pressure to be constant, the membrane performance in the reverse osmosis membrane module 2 can be kept almost constant, so that the equivalent water amount (fresh water amount) and the permeated water quality There is an advantage that the fluctuation of is relatively small. Still, it is inevitable that they change with the temperature change of the raw water. Further, in a reverse osmosis treatment apparatus constructed so as to make the amount of permeated water (the amount of fresh water) constant, the operating pressure thereof is adjusted, for example, in accordance with a change in the temperature of raw water. For this reason, for example, if the operating pressure is lowered so as to obtain a constant amount of permeated water by suppressing the amount of permeated water (amount of fresh water) that increases with an increase in the temperature of the raw water, the permeated water quality is significantly degraded. Occurs. Therefore, in order to maintain a high quality while always obtaining a constant amount of permeated water stably, it is essential to control the operating conditions of the reverse osmosis treatment device according to the raw water temperature and the permeated water quality.

The present invention has been made in view of such circumstances, and an object thereof is to maintain the quality of permeated water at a high quality irrespective of a change in the temperature of raw water or a change in the membrane performance of a reverse osmosis membrane module. It is an object of the present invention to provide a method of operating a reverse osmosis treatment apparatus, a control apparatus thereof, and a method of producing fresh water, which can reduce the fresh water cost while suppressing fluctuations in the amount of permeated water.

[0010]

According to the present invention, in order to achieve the above-mentioned object, the viscosity of raw water increases, the viscosity of the raw water decreases, and the permeability of the permeable membrane itself in the reverse osmosis membrane module unit increases. Increasing the permeation velocity,
On the other hand, the salt permeability due to the reverse osmosis effect in the reverse osmosis membrane module unit increases as the temperature increases, and the salt concentration in the permeated water at high temperatures increases, but it does not depend on the feed pressure of the raw water. It has been done.

Therefore, a method of operating a reverse osmosis treatment apparatus according to the present invention is directed to a reverse osmosis treatment apparatus which obtains permeated water by boosting raw water and supplying it to a plurality of reverse osmosis membrane module units provided in parallel. In operation, the number of the reverse osmosis membrane module units to be operated is controlled according to the temperature of the raw water and / or the quality of the permeated water.

Preferably, the operation number of the reverse osmosis membrane module unit is controlled so that the change in the amount of permeated water falls within a predetermined range. Then, the total salt concentration is washed as the quality of the permeated water. Then, the permeation of the salt in the reverse osmosis membrane module unit does not depend on the operating pressure, but increases as the raw water temperature increases, and as the water permeability increases, the raw water temperature increases. In order to improve the quality of the permeated water when it is high, the supply pressure (operating pressure) of the raw water is increased, and the amount of permeated water becomes excessive. Accordingly, the amount of permeated water is suppressed by reducing the number of operating water. .

Further, the fresh water producing method according to the present invention is characterized in that the permeated water is stably obtained by using the above-mentioned operation method as described in claim 4. Further, the control device of the reverse osmosis treatment device according to the present invention controls the operating conditions of the reverse osmosis treatment device that boosts raw water and supplies it to a plurality of reverse osmosis membrane module units provided in parallel to obtain the permeated water. Means for setting or controlling, the means for measuring the total salt concentration in the permeate and / or the means for measuring the temperature of the permeate; and the reverse osmosis membrane module according to the measured total salt concentration and / or temperature. Means for controlling the number of operating units.

Further, the reverse osmosis treatment device according to the present invention is provided with the above-mentioned control device as described in claim 6, so that the permeated water having high permeated water quality can be stably suppressed by suppressing the fluctuation of the permeated water amount. Moreover, it is characterized by being obtained at low cost.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION Referring to the drawings, a method for operating a reverse osmosis treatment apparatus, a control apparatus therefor, and a method for producing fresh water according to an embodiment of the present invention will be described. A desalination plant will be described as an example. FIG.
FIG. 1 is a schematic configuration diagram of a main part of a reverse osmosis treatment device (plant) according to this embodiment. 1 is a reverse osmosis membrane obtained by increasing the pressure of feed water (seawater) that has been subjected to pretreatment such as sterilization and turbid component removal. This is a high-pressure pump supplied to the module unit 2. In the plant shown in this embodiment, a plurality of reverse osmosis membrane module units 2a, 2b, to 2n are provided in parallel in a plurality of operation series, and input valves 3a, 3b provided on the supply side thereof. , To 3n are selectively operated. In addition to controlling the number of operating units (the number of operating series) of the plurality of reverse osmosis membrane module units 2a, 2b, to 2n,
It is, of course, possible to switch and control the number of operating reverse osmosis membrane elements constituting each unit 2.

By the way, each of these reverse osmosis membrane modules
The units 2a, 2b, to 2n may include only the one-stage reverse osmosis membrane module unit 2 described above with reference to FIG. 6, but are shown in FIGS. 9 to 11, respectively. As described above, a so-called permeated water two-stage method or a concentrated water two-stage method having two stages of reverse osmosis membrane module units 2x and 2y may be employed.

The reverse osmosis membrane module unit 2
With respect to the above, the reverse osmosis membrane element described above may be used alone, or a reverse osmosis membrane module having a structure in which a plurality of reverse osmosis membrane elements are connected in series and housed in a predetermined pressure vessel may be used. Further, the reverse osmosis membrane modules may be connected in series or in parallel. The permeated water (fresh water) that has passed through each of the reverse osmosis membrane module units 2a, 2b, to 2n is output from the output valve 4a,
4b, through 4n, are collectively taken out as the generated water. Also, each osmosis membrane module unit 2a, 2
Components that have not passed through b, .about.2n are discharged through the discharge valve 5 as seawater concentrated by the reverse osmosis membrane.

The operation management / control section 6 of the plant is generally provided with a permeated water quality management section 6a, a permeated water quantity management section 6b, an operation pressure control section 6c, and an operation number control section 6d. The operation management / control unit 6 basically supplies the seawater supply pressure Δ to the reverse osmosis membrane module 2.
The operating conditions of the plant are controlled in accordance with P, the temperature T of the raw water, the total salt concentration Cf of the raw water, the total salt concentration (permeate quality) Cpo of the permeate water, the permeate flow rate (water production amount) Qpo, and the like.

More specifically, the operation management / control unit 6 determines the operation pressure (seawater supply pressure to the reverse osmosis membrane module 2) Δ detected by the pressure sensor 7a provided on the raw water supply side.
P, the temperature T of the raw water (seawater) detected by the temperature sensor 7b, the total salt concentration Cf of the raw water measured by a salt concentration meter 7c including an electric conductivity meter, and the salt concentration provided on the permeate extraction side. The total salt concentration Cpo in the permeated water measured by the total 7d and the permeated water flow rate (fresh water amount) Qpo measured by the flow meter 7e are input as information indicating the operation state of the plant. In accordance with the detection information, the driving conditions of the high-pressure pump 1 are controlled as described later, and the number of operating reverse osmosis membrane module units 2 (reverse osmosis membrane elements) by opening and closing the input valves 3a, 3b, to 3n. It is configured to execute switching control and the like.

Here, the characteristics of the reverse osmosis membrane incorporated in the reverse osmosis membrane module unit 2 will be briefly described. The reverse osmosis membrane basically allows permeation of water while blocking permeation of salts. That is, the permeating substance permeating the reverse osmosis membrane is composed of a solvent and a solute, and the solvent (water) permeates the reverse osmosis membrane due to a pressure difference, while the solute (salt) permeates the reverse osmosis membrane according to a concentration difference. , Does not depend on the pressure difference.

Therefore, when the supply pressure of raw water increases, the amount of permeated water increases as a result of this, but the amount of permeated salt does not change unless the membrane characteristics change. Specifically, for example, as shown in FIGS. 2 (a) and 2 (b), the change in the salt exclusion rate and the change in the amount of fresh water (the amount of permeated water) with respect to the operating pressure of the reverse osmosis membrane (the supply pressure of raw water) are shown. Although the salt rejection ratio (membrane performance) hardly changes, the amount of permeated water greatly changes according to the operating pressure, and the amount of permeated water (amount of fresh water) increases as the operating pressure increases.

As a result, for example, when the supply pressure (operating pressure) of the raw water is increased, the permeation amount of water (solvent), which is the amount of water produced, is increased although the permeation amount of salt (solute) hardly changes. As the ratio increases, the ratio of the permeated salt to the permeated water decreases, so that the permeated water quality is improved. On the other hand, if the supply pressure of raw water decreases, water (solvent)
Although the amount of permeated water decreases, the amount of permeated salt hardly changes, so that the ratio of permeated salt to permeated water increases and the quality of permeated water deteriorates.

On the other hand, the characteristics of the reverse osmosis membrane change depending on the temperature of the raw water. Specifically, as the temperature of the raw water increases, the permeability of both water and salt increases. Incidentally, the increase in water permeability is caused by a decrease in the viscosity of water with an increase in temperature. On the other hand, the increase in the permeability of the salt is caused by the fact that the amount of the salt that moves with the water increases as the viscosity of the water decreases, and that the diffusion coefficient of the salt increases. In addition, although the membrane itself may change, the salt permeability is more sensitive. Therefore, when the raw water temperature rises, the rise in the permeation rate of the salt becomes larger than the rise in the permeation rate of the water. .

FIGS. 3 (a) and 3 (b) show the change in the salt exclusion rate and the change in the amount of fresh water (the amount of permeated water) with respect to the raw water temperature of the reverse osmosis membrane. As shown in this characteristic, although the permeated water amount (water production amount) increases as the temperature of the raw water increases, the salt rejection rate (membrane performance) gradually decreases. As a result, when the temperature of the raw water increases, it may be difficult to maintain the salt rejection rate sufficiently high.

The operation management and control unit 6 described above determines the amount of permeated water and the water quality (total salt concentration) determined through the reverse osmosis membrane module unit 2 by the reverse osmosis membrane module.
Focusing not only on the pressure of the raw water (seawater) supplied to the unit 2 but also on the temperature thereof, the raw water (seawater) is controlled while controlling the amount of the permeated water together with the permeated water quality, or according to the raw water temperature. In addition to controlling the supply pressure of seawater), the number of operating reverse osmosis membrane module units 2 is controlled.

More specifically, the operation management / control unit 6 detects the water quality (total salt concentration) Cpo of the permeated water obtained through, for example, the reverse osmosis membrane module unit 2 using the salt concentration meter 7d. . When the total salt concentration Cpo of the permeated water increases, the operation of the high-pressure pump 1 is controlled so as to satisfy a predetermined water quality standard (to reduce the total salt concentration), and the reverse osmosis membrane module unit 2 (2a , 2b,..., 2n). At this time, the supply pressure is increased according to the range of the pressure resistance of the reverse osmosis membrane module unit 2 (2a, 2b, to 2n), and the number of operation of the reverse osmosis membrane module unit 2 (2a, 2b, to 2n) (The number of operation lines) is reduced, and the amount of fresh water is kept substantially constant. In other words, a reverse osmosis membrane module
Unit 2 (2a, 2b, up to 2n) decreases the amount of fresh water with the decrease in the number of operation units (the number of operation lines). As the amount of fresh water decreases, the operating pressure is increased to increase the amount of permeated water and keep the amount of fresh water almost constant. However, the permeated water quality is kept within a predetermined water quality standard range.

The reverse osmosis membrane module unit 2 (2
The switching of the number of operation (the number of operation series) of (a, 2b, to 2n) is performed, for example, by selectively closing the input valves 3a, 3b, to 3n described above. In addition, the switching of the number of operation may be performed while monitoring the permeated water flow rate (amount of fresh water) Qpo measured by the flow meter 7e.

Alternatively, the operation management / control unit 6 includes:
In accordance with the temperature T of the raw water (seawater) detected by the temperature sensor 7b, the total salt concentration increases with the rise of the raw water temperature based on the relationship between the raw water temperature registered in a table or the like in advance and the total salt concentration in the permeated water. Of the reverse osmosis membrane module unit 2 (2a, 2b, to 2) according to the estimation result.
The control of the supply pressure of the raw water (seawater) to n) and the switching control of the number of operation (number of operation series) of the reverse osmosis membrane module unit 2 (2a, 2b, to 2n) are performed.

In this way, the reverse osmosis treatment unit (2) is configured to control the supply pressure ΔP of the raw water (sea water) to the reverse osmosis membrane module unit 2 (2a, 2b,... According to the plant, a substantially constant amount of permeated water can be obtained while maintaining the total salt concentration Cpo of the permeated water required through the reverse osmosis membrane module unit 2 at or below a predetermined water quality standard. Since the osmosis membrane module units 2a, 2b, to 2n do not need to be constantly operated at full capacity, it is possible to reduce the operation cost and, consequently, the fresh water production cost. Further, there is an effect that it is possible to always obtain permeated water having a stable water quality (total salt concentration) without being concerned with a temperature change of raw water (sea water).

FIG. 4 shows a plurality of reverse osmosis membrane module units 2a, 2b, to 2n, in which four reverse osmosis membrane elements are provided in parallel to permeate raw water (seawater) having a total salt concentration of 35,000 mg / liter. The operating pressure ΔP with respect to the raw water temperature T (indicated by ● in the figure) and the permeated water quality (total salt concentration of the permeated water) when the operation is controlled as described above under the conditions of 50 m ³ / day of raw water production and a raw water recovery rate of 40%. Cpo; 印 in the figure) also shows the number of operating reverse osmosis membrane elements. Incidentally, in the experimental example shown in FIG. 4, when the raw water temperature is 20 ° C. or lower, four reverse osmosis membrane elements are operated in parallel, and one reverse osmosis membrane element is stopped when the raw water temperature exceeds 20 ° C. When the raw water temperature exceeds 27.5 ° C., two reverse osmosis membrane elements are stopped to perform two parallel operations.

On the other hand, FIG. 5 shows, as a comparative example, the operating pressure ΔP with respect to the raw water temperature T and the permeated water quality (total salt concentration of the permeated water) when the number of reverse osmosis membrane elements is operated without switching control. Are shown. As is clear from comparison of FIGS. 4 and 5, a plurality of reverse osmosis membrane elements (reverse osmosis membrane module units 2a, 2b, to 2n) are changed while the operating pressure is changed according to the raw water temperature.
By controlling the number of operating units, the fluctuation of the permeated water quality can be suppressed within a certain range. For example, even in the worst case, the permeated water quality can be controlled while keeping the total salt concentration Cpo at 100 mg / liter or less. Water can be obtained stably. In addition, the operating pressure ΔP only needs to be increased in accordance with the decrease in the amount of fresh water due to the decrease in the number of operating reverse osmosis membrane elements. Therefore, the high-pressure pump 1 and the plurality of reverse osmosis membrane module units 2a, 2b,. Control can be performed relatively easily without imposing a large burden on 2n.

By frequently switching the operation number of the plurality of reverse osmosis membrane module units 2a, 2b, to 2n, damage to the reverse osmosis membrane module units 2a, 2b, to 2n due to a so-called water hammer can be prevented. If there is a concern, the switching control response may be reduced. Specifically, when the temperature change of the raw water per day is large, the switching control may be performed in units of time, and when the temperature change is gradual such as seawater, the control is performed in units of days. The switching control may be performed.

Alternatively, it is also useful to provide a predetermined control width to the set temperature of the switching control, and to perform the switching control in a hysteretic manner. Specifically, when the raw water temperature T exceeds the temperature [t + α] with respect to the set temperature t, the reverse osmosis membrane module unit 2a,
2b, ~ 2n is reduced by one and the raw water temperature T
When the temperature exceeds [t-β], the number of reverse osmosis membrane module units 2a, 2b, to 2n is increased by one, and the reverse osmosis membrane module units 2a, 2b,
The set temperature t may be set to a plurality of levels in accordance with the number of equipments of up to 2n. Here, α and β are both positive numbers.

In the experimental examples shown in FIGS. 4 and 5, the operating pressure was decreased as the temperature of the raw water increased. On the contrary, the operating pressure was increased as the temperature of the raw water increased, so that the quality of the permeated water was substantially constant. At the time when the amount of fresh water is excessively increased or the operating pressure approaches the pressure resistance of the reverse osmosis membrane.
It is also possible to perform control so as to reduce the number of operating lines a, 2b, to 2n.

Further, the membrane performance of the reverse osmosis membrane module unit 2 is evaluated based on the total salt concentration of the raw water and the total salt concentration of the permeated water, and the operation of the reverse osmosis membrane module unit 2 is performed according to the evaluation. It is of course possible to control the number of switches. In addition, the present invention can be applied not only to a plant that generates fresh water from seawater or brackish water, but also to a system that obtains permeated water from river water or lake water.
Further, in the embodiment, the control is performed by focusing on the total salt concentration in the permeated water, but the concentration of a specific component such as boron or bromine contained in the permeated water is detected, or the concentration is determined based on the total salt concentration. Of course, it is also possible to perform the control while estimating the concentration of the component. In addition, the present invention can be variously modified and implemented without departing from the gist thereof.

[0036]

As stated above, according to the present invention, a plurality of reverse osmosis membrane modules are provided in parallel, and the reverse osmosis membrane modules are provided in accordance with the temperature of raw water and / or the quality of the permeated water. Since the number of operating units is switched and controlled,
It is possible to obtain stable permeated water with good water quality regardless of the temperature change of the raw water, and to reduce the operation cost while keeping the amount of fresh water constant. Can be played. In addition, the operation of the reverse osmosis treatment device can be easily and effectively controlled by the selective switching control of the valve.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a main part of a reverse osmosis treatment device (plant) according to an embodiment of the present invention.

FIG. 2 is a diagram showing a change in the rejection ratio of all salts and a change in fresh water production (permeated water production) with respect to the operating pressure of the reverse osmosis membrane (supply pressure of raw water).

FIG. 3 is a diagram showing a change in the rejection rate of all salts with respect to a raw water temperature of a reverse osmosis membrane, and a change in a water production amount (permeate water amount).

FIG. 4 is a diagram showing a change characteristic of an operating pressure ΔP with respect to a raw water temperature T and a permeated water quality (total salt concentration Cpo of permeated water) when the switching control of the number of operated vehicles according to the present invention is executed.

FIG. 5 is a diagram showing a case where control for switching the number of operation is not performed.
The figure which shows the operating pressure (DELTA) P with respect to the raw water temperature T, and the change characteristic of permeate water quality (total salt concentration Cpo of permeate water).

FIG. 6 is a schematic diagram showing a basic configuration of a main part of a reverse osmosis treatment device provided with a reverse osmosis membrane module.

FIG. 7 is a schematic configuration diagram of a reverse osmosis membrane module.

FIG. 8 is a diagram showing a configuration example of a reverse osmosis membrane element constituting a reverse osmosis membrane module.

FIG. 9 is a schematic configuration diagram of a reverse osmosis treatment device (two-stage permeated water method) including two stages of reverse osmosis membrane modules.

FIG. 10 is a schematic configuration diagram of a reverse osmosis treatment device (concentrated water two-stage method) provided with two stages of reverse osmosis membrane modules.

FIG. 11 shows a reverse osmosis treatment device (concentrated water 2) comprising a reverse osmosis membrane module in two stages and a non-powered compressor.
FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 High-pressure pump 2,2a, 2b, ~ 2n Reverse osmosis membrane module unit 3a, 3b, ~ 3n Input valve 6 Operation management / control part 6a Permeate water quality management part 6b Permeate water amount management part 6c Operation pressure control part 6d Operation number control Part 7a Pressure sensor 7b Temperature sensor 7c Salt concentration meter 7d Salt concentration meter 7e Flow meter

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[Procedure amendment]

[Submission date] March 2, 2001 (2001.3.2)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claim 3

[Correction method] Change

[Correction contents]

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0012

[Correction method] Change

[Correction contents]

Preferably, the operation number of the reverse osmosis membrane module unit is controlled so that the change in the amount of permeated water falls within a predetermined range. Then, the total salt concentration is selected as the quality of the permeated water. Then, the permeation of the salt in the reverse osmosis membrane module unit does not depend on the operating pressure, but increases as the raw water temperature increases, and as the water permeability increases, the raw water temperature increases. In order to improve the quality of the permeated water when it is high, the supply pressure (operating pressure) of the raw water is increased, and the amount of permeated water becomes excessive. Accordingly, the amount of permeated water is suppressed by reducing the number of operating water. .

[Procedure amendment 3]

[Document name to be amended] Statement

[Correction target item name] Explanation of sign

[Correction method] Change

[Correction contents]

[Description of Signs] 1 , 1y high pressure pump 2, 2a, 2b, -2n , 2x, 2y reverse osmosis membrane module unit 3, 3a, 3b,-3n Input valve 4, 4a, 4b,-4n Output valve 5 Discharge Valve 6 Operation management / control unit 6a Permeated water quality management unit 6b Permeated water amount management unit 6c Operation pressure control unit 6d Operation number control unit 7a Pressure sensor 7b Temperature sensor 7c Salt concentration meter 7d Salt concentration meter 7e Flow meter 10 Spiral reverse osmosis membrane Element 11 Center pipe 12 Permeate liquid flow path material 13 Reverse osmosis membrane 14 Mesh spacer 15 Brine seal 16 Product end cap 20 Reverse osmosis membrane module 21 Pressure vessel 22 Joint 23 Water supply port 24 Permeate water port 25 Outlet

Continued on the front page (72) Inventor Takeshi Uchiyama 1-8-1, Mihama, Urayasu-shi, Chiba F-term (reference) 4D006 GA03 HA61 HA62 HA65 JA57A JA58A KA51 KA54 KA55 KA63 KA67 KE03Q KE06P KE06Q KE14P KE14Q KE16P KE16Q KE23Q PB03 PB04 PB24

Claims (6)

[Claims] 1. When operating a reverse osmosis treatment device for obtaining permeated water by supplying raw water to a plurality of reverse osmosis membrane module units connected in parallel with increasing pressure, the temperature of the raw water and / or the permeated water Operating the number of the reverse osmosis membrane module units in accordance with the water quality of the reverse osmosis treatment apparatus. 2. The method for operating a reverse osmosis treatment apparatus according to claim 1, wherein the number of operating reverse osmosis membrane module units is controlled such that the flow rate of the permeated water is within a predetermined range. 3. The method for operating a reverse osmosis treatment apparatus according to claim 1, wherein the total salt concentration is washed as the quality of the permeated water. 4. A fresh water producing method characterized by obtaining permeated water by using the operating method according to claim 1. 5. A control device for setting or controlling operating conditions of a reverse osmosis treatment apparatus for supplying raw water to a plurality of reverse osmosis membrane module units connected in parallel by increasing pressure and obtaining permeated water, Measuring means for measuring the total salt concentration in water and / or means for measuring the temperature of the permeated water, and control for controlling the number of operating reverse osmosis membrane module units according to the measured total salt concentration and / or temperature And a control device for the reverse osmosis treatment device. 6. A reverse osmosis treatment device comprising the control device according to claim 5.