JP2023031981A - Water treatment system and sterilization method of water treatment system - Google Patents

Abstract

To provide a water treatment system capable of completing hot water sterilization in a short time by supplying a sufficient amount of hot water to a secondary processor via a reverse osmosis membrane device.SOLUTION: A water treatment system relating to one embodiment of the present invention comprises: a reverse osmosis membrane device for membrane-separating target water to permeated water and membrane concentrated water; a supply line for supplying the target water to the reverse osmosis membrane device; a permeated water line having a permeated water flow meter which leads the permeated water from the reverse osmosis membrane device and detects a flow rate of the permeated water; a membrane concentrated water line having a membrane concentrated water flow meter which leads the membrane concentrated water from the reverse osmosis membrane device and detects a flow rate of the membrane concentrated water and a flow rate regulating valve which regulates the flow rate of the membrane concentrated water; a temperature regulator for regulating a temperature of germicidal treatment water; and a controller for controlling an output of the temperature regulator so that the temperature of the germicidal treatment water shows a predetermined change when the germicidal treatment water is supplied to the supply line as well as controlling an opening of the flow rate regulating valve so as to maintain a ratio of a detection value of the permeated water flow meter and a detection value of the membrane concentrated water flow meter at a set value.SELECTED DRAWING: Figure 1

Description

The present invention relates to a water treatment system and a method of sterilizing a water treatment system.

Equipped with a reverse osmosis membrane device that separates target water into permeated water and concentrated water using a reverse osmosis membrane, and a secondary treatment device such as an EDI device that further treats the permeated water flowing out of the reverse osmosis membrane device. A water treatment system is used. When manufacturing water for pharmaceuticals, food, etc. using such a water treatment system, in order to prevent the propagation of microorganisms in the water treatment system, hot water is passed through the water treatment system to known to sterilize. For example, in Patent Document 1, by forming a circulation system that circulates hot water between an inactivation device, a reverse osmosis membrane device, an EDI device, and a heat exchanger connected in series, without using a tank discloses an apparatus capable of performing hot water sterilization.

Japanese Patent No. 5459704

A water treatment system equipped with a reverse osmosis membrane device increases the amount of water supplied to the reverse osmosis membrane by recirculating the concentrated water flowing out of the reverse osmosis membrane device to the upstream side of the reverse osmosis membrane device, and the shear force of the fluid Many of them are configured to prevent clogging of the membrane surface and to prevent scale formation at high concentration due to membrane surface concentration polarization. In the hot water sterilization of the water treatment system having such a configuration, only the hot water flowing out of the permeate flow path is supplied to the secondary treatment device, but the flow rate of the permeate fluctuates as the temperature changes. , it takes time to heat up the whole system.

Therefore, the present invention provides a water treatment system and a water treatment system sterilization method that can complete hot water sterilization in a short time by supplying a sufficient amount of hot water to a secondary treatment device through a reverse osmosis membrane device. With the goal.

A water treatment system according to an aspect of the present invention includes a reverse osmosis membrane device that separates target water into permeated water and membrane concentrated water by a reverse osmosis membrane, and a supply line that supplies the target water to the reverse osmosis membrane device. a permeated water line having a permeated water flow meter for deriving the permeated water from the reverse osmosis membrane device and detecting the flow rate of the permeated water; and deriving the membrane concentrated water from the reverse osmosis membrane device, the membrane A membrane concentrated water line having a membrane concentrated water flow meter that detects the flow rate of the concentrated water and a flow control valve that adjusts the flow rate of the membrane concentrated water, and a supply line for sterilizing the reverse osmosis membrane device. and a temperature control device for controlling the temperature of the sterilized water, and controlling the output of the temperature control device so that the temperature of the sterilized water changes by a predetermined value when the sterilized water is supplied to the supply line. and a control device for controlling the opening degree of the flow control valve so as to maintain the ratio between the detected value of the permeated water flowmeter and the detected value of the membrane concentrated water flowmeter at a set value.

In the water treatment system described above, the control device raises the temperature of the sterilized water to a predetermined sterilization temperature, holds the temperature of the sterilized water at the sterilization temperature for a predetermined holding time, and then Controlling the output of the temperature control device so as to lower the temperature of the sterilized water, and controlling the permeate flowmeter at least while the temperature of the sterilized water is increased and while the temperature of the sterilized water is decreased. The opening degree of the flow control valve may be controlled so as to maintain the ratio between the detected value of and the detected value of the membrane concentrated water flow meter at a set value.

The water treatment system described above may further comprise a secondary treatment device for treating the permeate discharged from the permeate line.

In the water treatment system described above, the secondary treatment device may be an EDI device that obtains purified water in which ions are removed from the permeated water by regenerative desalination and electroconcentrated water in which the ion content is increased. good.

The water treatment system described above may further include a thermal sterilization line that supplies the sterilized water to the supply line and returns the sterilized water to the temperature control device from the reverse osmosis membrane device and thereafter.

In the water treatment system described above, the thermal sterilization line has a sterilization pump that circulates the sterilized water, and the control device stops the pump that supplies the target water to the reverse osmosis membrane device, The sterilized water may be supplied to the supply line.

A sterilization method for a water treatment system according to one aspect of the present invention includes a reverse osmosis membrane device that separates target water into permeated water and membrane concentrated water by a reverse osmosis membrane, and supplying the target water to the reverse osmosis membrane device. a feed line leading out the permeated water from the reverse osmosis membrane device, a permeated water line having a permeated water flow meter for detecting the flow rate of the permeated water, and leading out the membrane concentrated water from the reverse osmosis membrane device a membrane concentrated water flow meter for detecting the flow rate of the membrane concentrated water; and a membrane concentrated water line having a flow control valve for adjusting the flow rate of the membrane concentrated water. A sterilization method for sterilizing by supplying sterilized water, comprising: raising the temperature of the sterilized water to a predetermined sterilization temperature; and maintaining the temperature of the sterilized water at the sterilization temperature for a predetermined time. and a step of lowering the temperature of the sterilized water, wherein at least in the step of raising the temperature and the step of lowering the temperature, the detected value of the permeate flowmeter and the detection of the membrane concentrated water flowmeter The opening degree of the flow control valve is controlled so as to maintain the ratio to the value at the set value.

According to the present invention, it is possible to provide a water treatment system and a water treatment system sterilization method that can complete hot water sterilization in a short time by supplying a sufficient amount of hot water to a secondary treatment device through a reverse osmosis membrane device.

BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic diagram which shows the structure of the water treatment system which concerns on one Embodiment of this invention.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic diagram showing the configuration of a water treatment system 100 according to one embodiment of the present invention.

The water treatment system 100 includes a target water tank 1 , a reverse osmosis membrane device 2 , an EDI device 3 , a purified water tank 4 and a temperature control device 5 . The water treatment system 100 further includes a supply line 10, a permeate line 20, a membrane concentrated water line 30, a reflux line 40, a purified water line 50, an electrically concentrated water line 60, a heat sterilization line 70, and a control device 80 .

As will be described in detail later, the water treatment system 100 includes a production operation in which target water is treated by the reverse osmosis membrane device 2 and the EDI device 3 to produce purified water, and a temperature-controlled sterilization process by the temperature control device 5. A sterilization operation for hot water sterilization of each component with water and a regeneration operation for regenerating the EDI device 3 are repeatedly performed.

The target water tank 1 stores target water (raw water). Relatively clean water is assumed as the target water, and for example, water that has been purified in advance, such as tap water, can be used.

The reverse osmosis membrane device 2 separates target water into permeated water that has passed through the reverse osmosis membrane and membrane concentrated water that has not passed through the reverse osmosis membrane.

The EDI device 3 obtains purified water (pure water) in which ions are removed from the permeated water by electroregenerative desalination, and electroconcentrated water in which the ion content of the permeated water is increased. The EDI device 3 is an example of a secondary treatment device that further processes the permeated water derived from the reverse osmosis membrane device 2 .

Purified water tank 4 stores purified water generated by EDI device 3 .

A temperature control device 5 controls the temperature of the water that is passed through or temporarily retained. As a specific example of the temperature control device 5, a heat exchanger that controls the temperature of water in the system by exchanging heat with a hot heat source fluid such as water vapor supplied from the outside, for example, a heat source such as an electric heater or a burner. can be used. The temperature control device 5 may have only the function of heating water, but may also have the function of cooling water. For example, the temperature control device 5 can be a heat exchanger capable of exchanging heat between water in the system and a cold heat source fluid such as cooling water.

The supply line 10 supplies target water from the target water tank 1 to the reverse osmosis membrane device 2 . The supply line 10 can be configured to have a target water shutoff valve 11 that shuts off the target water and a supply pump 12 that pressurizes the target water in this order. A thermal sterilization line 70 and a reflux line 40 are connected in this order to the supply line 10 between the target water cutoff valve 11 and the supply pump 12 .

The permeate line 20 leads the permeate from the reverse osmosis membrane device 2 and guides the permeate to the EDI device 3 . The permeated water line 20 includes a permeated water flow meter 21 for detecting the flow rate of permeated water, a permeated water discharge valve 22 for discharging the permeated water to the outside of the system, and a permeated water pump 23 for pressurizing the permeated water, in this order. can be configured to have

The membrane-concentrated water line 30 leads the membrane-concentrated water out of the reverse osmosis membrane device 2 and discharges it outside the system. The membrane concentrated water line 30 includes a membrane concentrated water flow meter 31 that detects the flow rate of the membrane concentrated water discharged outside the system, and a membrane concentrated water flow control valve 32 that adjusts the flow rate of the membrane concentrated water discharged outside the system. , and a membrane concentrated water switching valve 33 for switching the flow path so that the sterilized water flowing out to the membrane concentrated water line 30 during the sterilization operation is returned to the heat sterilization line 70 in this order. The membrane concentrated water line 30 extends from the reverse osmosis membrane device 2 and is arranged so as to wrap around the vicinity of the permeate pump 23 . This makes it possible to install the reflux line 40 straight and shorten its length.

The reflux line 40 connects the upstream side of the membrane concentrated water flow meter 31 of the membrane concentrated water line 30 and the upstream side of the supply pump 12 of the supply line 10 . The reflux line 40 has a check valve 41 that prevents flow from the supply line 10 side to the membrane concentrated water line 30 side. The reflux line 40 is arranged linearly. Moreover, it is preferable that the reflux line 40 is configured by a pipe having a constant diameter that matches the nominal diameter of the check valve 41 . Also, the check valve 41 is preferably arranged in the center of the reflux line 40 .

The upper limit of the respective distances from the valve body of the check valve 41 to both ends of the reflux line 40 is preferably six times the inner diameter of the reflux line 40, more preferably three times. By setting the distance from the valve body of the check valve 41 to the end of the reflux line 40 to be equal to or less than the upper limit, hot water is not allowed to flow through the reflux line 40 when the reverse osmosis membrane device 2 is sterilized with hot water. The hot water passing through the supply line 10 and the hot water passing through the membrane concentrated water line 30 enter the reflux line 40, and the entire reflux line 40 including the check valve 41 can be sufficiently heat sterilized. . The end of the reflux line 40 is the intersection of the center line of the reflux line 40 and the center line of the supply line 10 or the membrane concentrated water line 30 .

A purified water line 50 leads purified water from the EDI device 3 and guides the purified water to the purified water tank 4 . The purified water line 50 includes a purified water discharge valve 51 that discharges purified water to the outside of the system, and a purified water switch that switches the flow path so that the sterilized water that flows out to the purified water line 50 during the sterilization operation is returned to the thermal sterilization line 70. , and the valve 52 in this order.

The electroconcentrated water line 60 leads out the electroconcentrated water from the EDI device 3 and discharges the electroconcentrated water to the outside of the system. The electroconcentrated water line 60 may be configured to have an electroconcentrated water switching valve 61 that switches the flow path so that the sterilized water that flows out to the electroconcentrated water line 60 during the sterilization operation is returned to the thermal sterilization line 70 .

The heat sterilization line 70 supplies sterilization treated water used for sterilization of the reverse osmosis membrane device, that is, water whose temperature is adjusted by the temperature control device 5 and can be hot water during sterilization to the supply line 10, and after the reverse osmosis membrane device 2, That is, the sterilized water is recovered from the membrane concentrated water line 30 , the purified water line 50 and the electrically concentrated water line 60 . That is, the thermal sterilization line 70 is sterilized through the supply line 10, the reverse osmosis membrane device 2 and the EDI device 3, the permeated water line 20 and the membrane concentrated water line 30, the EDI device 3, the purified water line 50 and the electroconcentrated water line 60. Circulate treated water. For this reason, the thermal sterilization line 70 is provided with the temperature control device 5 and a sterilization pump 71 that delivers sterilized water through the temperature control device 5 . Further, the thermal sterilization line 70 can be configured to have a sterilization water cutoff valve 72 that cuts off connection with the supply line 10 and a sterilization water discharge valve 73 that discharges the sterilization water out of the system.

Controller 80 controls the operation of water treatment system 100 by controlling the operation of other components of water treatment system 100 . In other words, the control device 80 controls the other components such that the production operation for producing purified water by the water treatment system 100 and the sterilization operation for sterilizing the water treatment system 100 are repeatedly performed. Also, the control device 80 may control other components so as to perform a regeneration operation for regenerating the EDI device 3 in addition to the manufacturing operation and the sterilization operation. In addition, sterilization operation is operation|movement which implements one Embodiment of the sterilization method which concerns on this invention.

A production run may have an initial blowing step, a watering step, and a flushing step. In the initial blowing step, the purified water is discharged without introducing the water flowing out from the EDI device 3 into the purified water line 50 into the purified water tank 4 until the operating state is stabilized and sufficiently clean purified water is obtained. It is discharged out of the system through the valve 51 . In the initial blowing process, the purified water discharge valve 51 is omitted, and the purified water switching valve 52 allows water to flow from the purified water line 50 into the thermal sterilization line 70. It may be performed by discharging from the system to the outside of the system. In the water passing step, the purified water flowing out to the purified water line 50 through the reverse osmosis membrane device 2 and the EDI device 3 is introduced into the purified water tank 4 . In the flushing step, the opening degree of the membrane concentrated water flow control valve 32 is increased to reduce the concentration of impurities in the space on the membrane concentrated water side inside the reverse osmosis membrane device 2 and in the water inside the membrane concentrated water line 30. , the permeated water is discharged from the permeated water discharge valve 22 to the outside of the system.

The sterilization operation includes a preparatory step of discharging water remaining in the permeated water line 20, the membrane concentrated water line 30, the purified water line 50, and the electroconcentrated water line 60 to the outside of the system to reduce the amount of impurities in the system, and reverse osmosis. Sterilization that circulates sterilized water between the membrane device 2, the EDI device 3, and the temperature control device 5, and adjusts the output of the temperature control device 5 so that the temperature of the reverse osmosis membrane device 2 and the EDI device 3 approaches the target temperature. and a step.

In the sterilization step, the sterilization pump 71 circulates the sterilized water while the supply pump 12 and the permeated water pump 23 are stopped, and the temperature control device 5 is controlled so that the temperature of the sterilized water changes to a predetermined temperature. By circulating the sterilizing water in this way, hot water sterilization can be performed by circulating a relatively small amount of the sterilizing water, so that consumption of water and energy for sterilization can be suppressed. Further, by stopping the supply pump 12 , the sterilized water that has flowed out from the reverse osmosis membrane device 2 to the membrane concentrated water line 30 is not resupplied to the reverse osmosis membrane device 2 through the reflux line 40 . As a result, the temperature of the reverse osmosis membrane device 2 can be controlled accurately, so hot water sterilization can be performed quickly and appropriately. Further, by not using the feed pump 12 and permeate pump 23 in the sterilization process, the feed pump 12 and permeate pump 23 specifications can be optimized for manufacturing operations.

The sterilization step includes a temperature raising step of raising the temperature of the reverse osmosis membrane device 2 and the EDI device 3 to a preset sterilization temperature, and a step of raising the temperature of the reverse osmosis membrane device 2 and the EDI device 3 to a predetermined sterilization temperature. A temperature holding step of holding for a holding time and a temperature lowering step of lowering the temperatures of the reverse osmosis membrane device 2 and the EDI device 3 can be provided. That is, when the sterilized water is supplied to the supply line 10, the controller 80 raises the temperature of the sterilized water to a predetermined temperature, holds the sterilization temperature for a holding time, and then lowers the temperature to a predetermined temperature. The output of the temperature control device 5 is controlled to change. The sterilization temperature can be, for example, a temperature of 80°C or higher and 85°C or lower. The holding time may be, for example, 30 minutes or more and 1 hour or less, depending on the sterilization temperature. The temperature gradient of the reverse osmosis membrane device 2 and the EDI device 3 in the temperature rising process and the temperature decreasing process can be set to, for example, about 2° C./min in order to protect the reverse osmosis membranes.

The control device 80 controls the membrane so as to maintain the ratio between the detected value of the permeate flow meter 21 and the detected value of the membrane concentrated water flow meter 31 at a set value at least in the heating process and the cooling process, preferably throughout the sterilization process. Controls the degree of opening of the concentrated water flow control valve 32 . As a result, sufficient sterilized water is supplied to the downstream side of the reverse osmosis membrane device 2, and the temperature of downstream components such as the EDI device 3 can be changed with a small delay with respect to the reverse osmosis membrane device 2. Therefore, the entire system can be hydrothermally sterilized in a relatively short time.

In the regeneration operation, the EDI device 3 is energized, and the water flowing out from the EDI device 3 to the purified water line 50 is discharged from the sterilized water discharge valve 73 via the purified water discharge valve 51 or the heat sterilization line 70 to the outside of the system. As a result, the EDI device 3 can be regenerated to a state in which impurity ions can be removed from the permeated water.

As is clear from the above description, one embodiment of the sterilization method according to the present invention performed by the control device 80 is a sterilization method for sterilizing the water treatment system 100 by supplying temperature-controlled sterilization-treated water to the supply line 10. A step of raising the temperature of the sterilized water to a predetermined sterilization temperature, a step of holding the temperature of the sterilized water at the sterilization temperature for a predetermined holding time, and a step of lowering the temperature of the sterilized water; At least in the step of raising the temperature and the step of lowering the temperature, the membrane concentrated water flow rate control valve 32 is adjusted so that the ratio of the detected value of the permeated water flow meter 21 and the detected value of the membrane concentrated water flow meter 31 is held at the set value Control the degree of opening.

As described above, in the water treatment system 100, the ratio of the flow rate of the sterilized water flowing out to the permeate line 20 to the flow rate of the sterilized water flowing out to the membrane concentrated water line 30 by the controller 80 during hot water sterilization is maintained at the set value, sufficient sterilized water can be supplied to the downstream side of the reverse osmosis membrane device 2 as well. As a result, it is possible to give an appropriate heat history to other components such as the EDI device 3 on the downstream side of the reverse osmosis membrane device 2, so that the entire system can be appropriately sterilized with hot water in a relatively short time. can.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various changes and modifications are possible. As an example, the temperature control devices, pumps, flowmeters, control valves, etc. in the above-described embodiments may be arranged in different positional relationships within a range that does not impair their functions. Also, the configuration for switching the flow path may use a single three-way valve or two shutoff valves. Further, in the water treatment system according to the present invention, the EDI device may be omitted, and instead of or in addition to the EDI device, other secondary treatment devices such as UF membrane filtration devices and ion exchange devices may be used. may be provided. Also, in the water treatment system according to the present invention, the reflux line may be omitted. Moreover, the water treatment system according to the present invention may be configured to discharge sterilized water to the outside of the system without circulating it.

1 target water tank 2 reverse osmosis membrane device 3 EDI device 4 purified water tank 5 temperature control device 10 supply line 11 target water cutoff valve 12 supply pump 20 permeated water line 21 permeated water flow meter 22 permeated water discharge valve 23 permeated water pump 30 Membrane concentrated water line 31 Membrane concentrated water flow meter 32 Membrane concentrated water flow control valve 33 Membrane concentrated water switching valve 40 Reflux line 41 Check valve 50 Purified water line 51 Purified water discharge valve 52 Purified water switching valve 60 Electric concentrated water line 61 Electric concentrated water switching valve 70 Thermal sterilization line 71 Sterilization pump 72 Sterilization treated water cutoff valve 73 Sterilization treated water discharge valve 80 Controller 100 Water treatment system

Claims (7)

A reverse osmosis membrane device that separates target water into permeated water and membrane concentrated water by means of a reverse osmosis membrane;
a supply line for supplying the target water to the reverse osmosis membrane device;
a permeated water line having a permeated water flow meter for leading the permeated water from the reverse osmosis membrane device and detecting the flow rate of the permeated water;
a membrane concentrated water line having a membrane concentrated water flow meter for deriving the membrane concentrated water from the reverse osmosis membrane device and detecting the flow rate of the membrane concentrated water, and a flow control valve for adjusting the flow rate of the membrane concentrated water;
a temperature control device that adjusts the temperature of sterilized water supplied to the supply line to sterilize the reverse osmosis membrane device;
When the sterilized water is supplied to the supply line, the output of the temperature control device is controlled so that the temperature of the sterilized water changes by a predetermined value, and the detected value of the permeate flowmeter and the membrane a control device that controls the opening of the flow rate control valve so as to maintain the ratio to the detected value of the concentrated water flow meter at a set value;
Water treatment system with The control device is
After raising the temperature of the sterilization-treated water to a predetermined sterilization temperature, the temperature of the sterilization-treated water is maintained at the sterilization temperature for a predetermined holding time, and then the temperature of the sterilization-treated water is lowered. controls the output of the regulator,
At least while the temperature of the sterilized water is raised and while the temperature of the sterilized water is lowered, the ratio of the detected value of the permeate flow meter and the detected value of the membrane concentrated water flow meter is set to a set value. 2. The water treatment system according to claim 1, wherein the opening degree of said flow control valve is controlled to maintain. 3. The water treatment system according to claim 1 or 2, further comprising a secondary treatment device that treats the permeate discharged from the permeate line. The water treatment according to claim 3, wherein the secondary treatment device is an EDI device for obtaining purified water in which ions are removed from the permeated water by regenerative desalination and electroconcentrated water in which the ion content is increased. system. The water according to any one of claims 1 to 4, further comprising a heat sterilization line that supplies the sterilized water to the supply line and returns the sterilized water to the temperature control device from the reverse osmosis membrane device and thereafter. processing system. The thermal sterilization line has a sterilization pump that circulates the sterilized water,
6. The water treatment system according to claim 5, wherein said control device supplies said sterilized water to said supply line while a pump that supplies said target water to said reverse osmosis membrane device is stopped. A reverse osmosis membrane device that separates target water into permeated water and membrane concentrated water by means of a reverse osmosis membrane;
a supply line for supplying the target water to the reverse osmosis membrane device;
a permeated water line having a permeated water flow meter for leading the permeated water from the reverse osmosis membrane device and detecting the flow rate of the permeated water;
a membrane concentrated water line having a membrane concentrated water flow meter for deriving the membrane concentrated water from the reverse osmosis membrane device and detecting the flow rate of the membrane concentrated water, and a flow control valve for adjusting the flow rate of the membrane concentrated water;
A sterilization method for sterilizing a water treatment system comprising:
A step of raising the temperature of the sterilized water to a predetermined sterilization temperature;
a step of holding the temperature of the sterilized water at the sterilization temperature for a predetermined holding time;
a step of lowering the temperature of the sterilized water;
with
In at least the step of raising the temperature and the step of lowering the temperature, the degree of opening of the flow control valve is controlled so as to maintain the ratio between the detected value of the permeate flowmeter and the detected value of the concentrated water flowmeter at a set value. A method for sterilizing a water treatment system.

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