Water treatment system and water treatment method

Abstract

It suppresses the stagnation of water and air. [Solution] The water treatment system 10 includes a tank 11 for storing water to be treated, pretreatment means 14 and 15 for pretreatment of the water to be treated, and connection lines L3 and L4 which are connected to the upper part of the pretreatment means 14 and 15 on the upstream side and connected to the upper part of the tank 11 on the downstream side.

Description

Technical Field

[0001] The present invention relates to a water treatment system and a water treatment method.

Background Art

[0002] Conventionally, as an apparatus for producing pure water (such as purified water and water for injection) used in pharmaceutical manufacturing and the like, an apparatus is known that sequentially treats raw water such as city water with pretreatment apparatuses including a water softener and an activated carbon filter, and water treatment apparatuses including a membrane separation apparatus and an electric deionized water production apparatus. Due to the nature of producing pure water for use in pharmaceutical manufacturing and the like, such a pure water production apparatus regularly performs a sterilization treatment to reduce the number of viable bacteria in the system by, for example, passing hot water of 60°C or higher through the system, in order to meet the requirements of the Japanese Pharmacopoeia (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Incidentally, there is a concern that water tends to stay in the upper space inside the column constituting the above-mentioned pretreatment apparatus, which facilitates the propagation of viable bacteria. In addition, air also tends to stay in the upper space inside the column, which may cause a poor temperature rise during the hot water sterilization treatment, resulting in a failure to obtain a sufficient sterilization effect. However, as it stands, countermeasures against such retention of water and air have not been sufficiently studied so far.

[0005] Accordingly, an object of the present invention is to provide a water treatment system and a water treatment method that suppress the retention of water and air.

Means for Solving the Problems

[0006] To achieve the above-mentioned objectives, the water treatment system of the present invention includes a tank for storing water to be treated, a pretreatment means for pre-treating the water to be treated, and a connecting line connected to the upper part of the pretreatment means on the upstream side and connected to the upper part of the tank on the downstream side.

[0007] Furthermore, the water treatment method of the present invention includes the steps of: storing the water to be treated in a tank; pre-treating the water to be treated by passing it through a pre-treatment means before or after storing it in the tank; and allowing a portion of the water to be treated supplied to the pre-treatment means to flow into the tank through a connecting line that connects the upper part of the pre-treatment means and the upper part of the tank. [Effects of the Invention]

[0008] According to the present invention, the stagnation of water and air can be suppressed. [Brief explanation of the drawing]

[0009] [Figure 1] This is a schematic diagram of a pure water production apparatus according to the first embodiment of the present invention. [Figure 2] This is a schematic diagram of a pure water production apparatus according to a second embodiment of the present invention. [Modes for carrying out the invention]

[0010] Embodiments of the present invention will be described below with reference to the drawings. In this specification, the water treatment system of the present invention is exemplified by a pure water production apparatus that produces pure water, specifically purified water or water for injection, used in the manufacture of pharmaceuticals and the like, but the present invention is not limited thereto. In this specification, purified water means ordinary water that has been purified by ion exchange, reverse osmosis (RO), ultrafiltration (UF), or a combination thereof, and water for injection means purified water or water that has undergone appropriate pretreatment and has been treated by distillation or ultrafiltration (RO / UF) and has passed pyrogenic substance (endotoxin) tests and bacterial viability tests. Examples of such purified water and water for injection include those specified in the Japanese Pharmacopoeia.

[0011] (First embodiment) Figure 1 is a schematic diagram of a pure water production apparatus according to the first embodiment of the present invention. It should be noted that the configuration of the pure water production apparatus shown is merely an example and does not limit the present invention, and it goes without saying that it can be appropriately modified according to the purpose of use, application, and required performance of the apparatus.

[0012] The pure water production apparatus 10 sequentially processes raw water (water to be treated), such as tap water, to produce pure water and supplies that pure water to a pure water supply device (not shown). It comprises a raw water tank 11, a water pump 12, a heat exchanger 13, a water softener 14, an activated carbon filter 15, and a water treatment device 16. A water supply line L1 is connected to the raw water tank 11 to circulate the raw water in the raw water tank 11 and supply it to the water treatment device 16. The water pump 12, heat exchanger 13, water softener 14, and activated carbon filter 15 are located on the water supply line L1. A raw water replenishment line L2 is also connected to the raw water tank 11 to supply raw water as needed. Note that the heat exchanger 13, water softener 14, and activated carbon filter 15 do not necessarily have to be arranged in this order. Also, either the water softener 14 or the activated carbon filter 15 is not necessarily required to be provided.

[0013] The water supply pump 12 has the function of supplying raw water stored in the raw water tank 11 to the water treatment device 16, and its rotation speed may be controlled by an inverter (not shown). The heat exchanger 13 is used to control the temperature of the raw water, which fluctuates due to various factors such as seasonal temperature fluctuations and heat generation from the equipment, to a constant temperature (e.g., 25°C), and is also used as a heating means to generate hot water for heat sterilization during the hot water sterilization process described later. The water softener 14 is a column-shaped container filled with ion exchange resin (e.g., cation exchange resin, preferably Na-type strong acid anion exchange resin), and has the function of removing hardness components such as calcium and magnesium from the raw water supplied to the water treatment device 16. Although not shown, the water softener 14 is connected to a line for regenerating the ion exchange resin with saline solution (restoring ion exchange capacity). The activated carbon filter 15 is a column filled with activated carbon, and has the function of removing residual chlorine from the raw water supplied to the water treatment device 16. As a result, the activated carbon filter 15 functions as a pretreatment means for pretreatment of raw water supplied to the water treatment device 16, similar to the water softener 14. Although not shown in the figures, a filter is provided downstream of the activated carbon filter 15 to capture and remove pulverized carbon generated from the activated carbon filter 15. Such a filter is not particularly limited, and for example, a microfiltration membrane (MF membrane) or an ultrafiltration membrane (UF membrane) can be used.

[0014] The water softener 14 may be provided in two parallel systems, that is, the water supply line L1 may branch into two, with a water pump 12 and a water softener 14 provided in each. This allows the pure water production system 10 to continue operating, for example, if the function of one water softener 14 deteriorates and regeneration treatment is required, as the raw water can be treated with the other water softener 14. In this case, the heat exchanger 13 may be provided between the water pump 12 and the water softener 14 in each branch line, but considering the cost, it is preferable to provide it downstream of the two water softeners 14, that is, downstream of the confluence of the two branch lines. Furthermore, the activated carbon filter 15 may also be provided in two parallel systems, separate from the water softener 14, so that the activated carbon filter 15 can be backwashed without stopping the operation of the pure water production system 10.

[0015] A first water spray line (connection line) L3 is provided between the water softener 14 and the raw water tank 11. The first water spray line L3 is connected upstream to the upper part of the water softener 14, specifically near the raw water inlet (water to be treated inlet) preferably located at the top of the column, and downstream to the upper part of the raw water tank 11. A spray ball 21 is provided at the downstream end of the first water spray line L3, which is located inside the raw water tank 11, as a means of spraying water. The spray ball 21 has the function of spraying raw water into the raw water tank 11 during normal operation (pure water production) of the pure water production device 10, and hot water during the hot water sterilization process described later. The first water spray line L3 is provided with a flow control valve (flow control means) CV1 for adjusting the flow rate of raw water or hot water flowing from the water softener 14 into the first water spray line L3. Furthermore, during the regeneration of the water softener 14, the flow control valve CV1 is closed to block the inflow of saline solution into the first watering line L3. As a result, raw water tends to accumulate in the portion of the first watering line L3 from the connection point with the water softener 14 to the flow control valve CV1. Therefore, in order to minimize such stagnant areas, it is preferable that the flow control valve CV1 be located as close to the water softener 14 as possible. The flow control valve CV1 is not particularly limited as long as it can adjust the flow rate of raw water or hot water flowing through the first watering line L3 and has a fully closing function for the reasons mentioned above. For example, it may be a manual valve or an automatic valve that can be switched between fully closed and intermediate opening.

[0016] Furthermore, a second water spray line (connection line) L4 is provided between the activated carbon filter 15 and the raw water tank 11. The second water spray line L4 is connected upstream to the upper part of the activated carbon filter 15, specifically near the raw water inlet located at the top of the column, and downstream to the upper part of the raw water tank 11. A spray ball 22 is provided at the downstream end of the second water spray line L4, which is located inside the raw water tank 11, as a means of spraying water. The spray ball 22 has the function of spraying raw water into the raw water tank 11 during normal operation (pure water production) of the pure water production device 10, and hot water during the hot water sterilization process described later. The second water spray line L4 is provided with a flow control valve (flow control means) CV2 for adjusting the flow rate of raw water or hot water flowing from the activated carbon filter 15 into the second water spray line L4. Furthermore, during backwashing of the activated carbon filter 15, the flow control valve CV1 is closed to block the inflow of washing water into the second watering line L4. As a result, raw water tends to accumulate in the portion of the second watering line L4 from the connection point with the activated carbon filter 15 to the flow control valve CV2. Therefore, in order to minimize such stagnant areas, it is preferable that the flow control valve CV2 be located as close as possible to the activated carbon filter 15. The flow control valve CV2 is not particularly limited as long as it can adjust the flow rate of raw water or hot water flowing through the second watering line L4 and has a fully closing function for the reasons mentioned above. For example, it may be a manual valve or an automatic valve that can be switched between fully closed and intermediate opening.

[0017] The water treatment apparatus 16 is not particularly limited as long as it produces pure water for use in pharmaceutical manufacturing and the like, but preferably it has a membrane separation apparatus and an electrodeionized water production apparatus (hereinafter also referred to as the "EDI apparatus"). The membrane separation apparatus obtains permeate by membrane separation of raw water pretreated in the water softener 14 and activated carbon filter 15, and preferably has a nanofiltration membrane (NF membrane) or a reverse osmosis membrane (RO membrane) as such a separation membrane, and more preferably has an RO membrane. The EDI apparatus produces deionized water (pure water) by processing the permeate obtained from the membrane separation apparatus by combining electrophoresis and electrodialysis. The EDI apparatus has, for example, an anode and a cathode, a desalination chamber placed between the anode and cathode and filled with at least one of a cation exchanger and an anion exchanger, and a pair of concentration chambers placed on both sides of the desalination chamber via an ion exchange membrane. Since such membrane separation apparatuses and EDI apparatuses are known, as described in, for example, Japanese Patent Application Publication No. 2024-131086, further detailed explanation is omitted.

[0018] Furthermore, the water treatment device 16 may have a deaerating device, such as a membrane degasser or a decarbonation tower, between the membrane separation device and the EDI device to remove dissolved oxygen and carbon dioxide from the permeate water from the membrane separation device. In addition, the water treatment device 16 may have a filter downstream of the EDI device to capture and remove crushed resin generated from the EDI device, and an ultraviolet sterilizer to sterilize the pure water obtained from the EDI device by ultraviolet irradiation. Alternatively, or in addition to the EDI device, a non-regenerative or regenerative mixed-bed ion exchange device may be provided. In this case, a water spray line similar to those connected to the water softener 14 and activated carbon filter 15 may be provided between the ion exchange device and the raw water tank 11. That is, a water spray line may be provided that is connected to the top of the ion exchange device upstream and to the top of the raw water tank 11 downstream, and a spray ball similar to those provided in the water spray lines L3 and L4 may be provided at its downstream end.

[0019] The water treatment device 16 is connected to a pure water line L5 that circulates the pure water obtained in the water treatment device 16 and supplies it to the pure water tank of a pure water supply device (not shown). The pure water line L5 is equipped with an on-off valve V1, and near its upstream side, a pure water return line L6 is connected via an on-off valve V2 that branches off from the pure water line L5 and joins the raw water tank 11. This allows for the circulation of pure water within the pure water production device 10, for example, when the device is started up, when operation is restarted, or when there is no request for water sampling from the pure water tank of the pure water supply device. That is, by closing the on-off valve V1 of the pure water line L5 and opening the on-off valve V2 of the pure water return line L6, the pure water obtained in the water treatment device 16 can be returned to the raw water tank 11 through the pure water return line L6. This circulation of pure water can suppress the growth of viable bacteria due to the stagnation of pure water. A spray ball similar to those provided in the watering lines L3 and L4 may be provided at the downstream end of the pure water return line L6. Furthermore, a drainage line may be connected to the pure water return line L6 to discharge pure water to the outside as needed. Also, instead of the on / off valves V1 and V2, a three-way valve may be provided at the connection point between the pure water line L5 and the pure water return line L6.

[0020] During normal operation of the pure water production apparatus 10, a water sampling process is performed in which raw water stored in the raw water tank 11 is treated in the water treatment apparatus 16, and the resulting pure water is supplied to a pure water supply device (not shown) via the pure water line L5. Specifically, the raw water stored in the raw water tank 11 is supplied to the heat exchanger 13 by the operation of the water supply pump 12, adjusted to a constant temperature (e.g., 25°C), and then supplied to the water softener 14. Most of the raw water supplied to the water softener 14 has its hardness components removed during the process of passing through the water softener 14, and is then supplied to the activated carbon filter 15. Then, most of the raw water supplied to the activated carbon filter 15 has its residual chlorine removed during the process of passing through the activated carbon filter 15. The raw water thus pre-treated is supplied to the water treatment apparatus 16 by the operation of a pressure pump (not shown), where it is treated, and then sent as pure water to a pure water supply device (not shown) via the pure water line L5. Meanwhile, a portion of the raw water supplied to the water softener 14 is returned (flows into) the raw water tank 11 through the first spray line L3 and sprayed into the interior of the raw water tank 11 by the spray ball 21, particularly onto the upper inner wall surface. Similarly, a portion of the raw water supplied to the activated carbon filter 15 is also returned (flows into) the raw water tank 11 through the second spray line L4 and sprayed into the interior of the raw water tank 11 by the spray ball 22, particularly onto the upper inner wall surface. This spraying prevents water droplets from adhering to and accumulating on the upper inner wall surface of the raw water tank 11 during the water sampling process. In this case, for example, if the pump capacity of the water supply pump 12 is not very large, it is preferable to adjust the opening of the flow control valves CV1 and CV2 so that the amount of raw water returned to the raw water tank 11 does not become excessive, from the viewpoint of ensuring the amount of raw water supplied to the water treatment device 16.

[0021] A water level sensor (not shown) is provided in the raw water tank 11, and during the aforementioned water collection step, raw water is supplied through the raw water replenishment line L2 according to the water level in the raw water tank 11 detected by the water level sensor. Specifically, when the water level in the raw water tank 11 falls to or below a predetermined lower limit water level, an on-off valve (not shown) of the raw water replenishment line L2 is opened, whereby raw water is supplied to the raw water tank 11. Then, when the water level in the raw water tank 11 reaches a predetermined upper limit water level, the on-off valve (not shown) of the raw water replenishment line L2 is closed, whereby the supply of raw water to the raw water tank 11 is stopped.

[0022] Further, in the pure water production apparatus 10, due to the nature of producing pure water used for pharmaceutical production and the like, a hot water sterilization step of reducing the number of viable bacteria in the system with hot water is performed between the aforementioned water collection steps. The hot water sterilization step is a step of circulating the raw water stored in the raw water tank 11 in the system, heating the raw water to 60°C or higher, preferably 80°C or higher by the heat exchanger 13, maintaining the temperature for a certain period of time, and then cooling the system until the temperature in the system reaches a predetermined temperature (for example, lower than 45°C). Although not described in detail here, treated water from the water treatment device 16 (that is, permeated water from the membrane separation device or deionized water from the EDI device) may be used as the hot water for heat sterilization instead of raw water.

[0023] When the hot water sterilization step is started, the operation of the EDI device (application of DC voltage) in the water treatment device 16 is stopped, and the production of pure water is stopped. Then, the on-off valve V1 of the pure water line L5 is closed and the on-off valve V2 of the pure water return line L6 is opened, whereby the raw water in the raw water tank 11 is circulated through the water supply line L1 including the water softener 14 and the activated carbon filter 15, the pure water line L5, and the pure water return line L6. At the same time, a heat medium (for example, steam) is supplied to the heat exchanger 13, and the circulating raw water is heated and maintained until it reaches 60°C or higher, preferably 80°C or higher. In this way, the inside of the system of the pure water production apparatus 10 is sterilized by the circulation of the raw water (hot water) maintained at a high temperature. At this time, hot water is also passed through the water spray lines L3 and L4 for sterilization, and hot water is also sprayed onto the upper inner wall surface of the raw water tank 11 by the spray balls 21 and 22 for sterilization.

[0024] After the hot water has been circulated for a certain period of time, the supply of the heat medium to the heat exchanger 13 is stopped, and instead, a coolant (for example, cold water) is supplied to the heat exchanger 13, whereby cooling of the hot water is started. Then, when the circulating hot water is cooled to a predetermined temperature, specifically a temperature suitable for membrane separation treatment by the membrane separation device of the water treatment device 16 (for example, lower than 45°C), the operation of the EDI device (application of DC voltage) in the water treatment device 16 is resumed, and thereafter, the normal operation of the pure water production device 10 is resumed. That is, when it is confirmed that the water quality of the pure water from the EDI device satisfies a predetermined water quality, the on-off valve V1 of the pure water line L5 is opened, and the on-off valve V2 of the pure water return line L6 is closed, whereby the water collection step in which the pure water produced by the pure water production device 10 is supplied to a liquid supply device (not shown) through the pure water line L5 is resumed. The fact that the water quality of the pure water from the EDI device satisfies the predetermined water quality can be confirmed, for example, by detecting the electrical conductivity of the pure water with an electrical conductivity sensor (not shown) installed near the outlet of the water treatment device 16, and confirming that the detected value is equal to or less than a predetermined value (for example, 1 μS / cm).

[0025] As described above, in this embodiment, since the water spray lines L3 and L4 are connected to the top of the water softener 14 and the activated carbon filter 15, respectively, raw water can be passed through the upper space in each column during the water sampling process. This suppresses water from accumulating in such spaces, thereby inhibiting the growth of viable bacteria. In addition, air tends to accumulate in the upper space of the column, and during the hot water sterilization process, bubbles originating from dissolved gases in the raw water and gases remaining in the gaps of the packing material tend to accumulate there as well. However, such air and gases can be discharged to the outside through the water spray lines L3 and L4. Therefore, it is possible to suppress the occurrence of sterilization failure due to insufficient heating of air and gases in the water softener 14 and the activated carbon filter 15. Furthermore, in this embodiment, water is sprayed into the raw water tank 11 by spray balls 21 and 22 not only during the hot water sterilization process but also during the water sampling process (with the exception of cases due to the pump capacity of the water supply pump 12, etc.). Therefore, during the hot water sterilization process, the upper inner wall surface of the raw water tank 11 can be sufficiently heated, and during the water sampling process, water droplets adhering to the upper inner wall surface of the raw water tank 11 can be prevented from accumulating and coming into contact with air. As a result, the proliferation of viable bacteria in the upper part of the raw water tank 11 can be effectively suppressed throughout both processes.

[0026] As described above, the watering lines L3 and L4 are connected to the upper part of the column near the raw water inlet on the upstream side. Here, "upper part" preferably refers to the hemispherical portion of the column's top, and more preferably to the apex of the hemispherical portion. In other words, by connecting the watering lines L3 and L4 in this position, the accumulation of air in the upper space within the column can be suppressed as much as possible. However, the connection positions of the watering lines L3 and L4 are not particularly limited as long as air does not accumulate in the upper space within the column due to the structure.

[0027] The number of spray balls 21 and 22 is not limited to one each; multiple spray balls 21 and 22 may be provided in each watering line L3 and L4. That is, the downstream side of the first watering line L3 may branch into multiple lines, each of which may be provided with a spray ball 21. Similarly, the downstream side of the second watering line L4 may also branch into multiple lines, each of which may be provided with a spray ball 22. This makes it possible to spray water over a wider area within the raw water tank 11, more reliably suppressing the adhesion of water droplets during the water sampling process and increasing the heating efficiency during the hot water sterilization process.

[0028] For example, when tap water is used as raw water, the raw water contains residual chlorine. Therefore, in order to effectively utilize the sterilizing effect of such residual chlorine, it is preferable that the water is passed through the water softener 14 or sprayed into the raw water tank 11 before the residual chlorine in the raw water is removed by the activated carbon filter 15. In other words, by passing the raw water containing residual chlorine through the water softener 14 or spraying it into the raw water tank 11 before passing it through the activated carbon filter 15, the growth of viable bacteria in the water softener 14 and the raw water tank 11 can be suppressed. Therefore, as described above, the positions of the water softener 14 and the activated carbon filter 15 may be reversed. For example, the activated carbon filter 15 may be located upstream of the water softener 14, but it is preferable that the activated carbon filter 15 be located downstream of the water softener 14, as shown in the figure. Furthermore, while the flow of raw water through the activated carbon filter 15 may be carried out in an upward flow, it is preferable to carry it out in a downward flow, as shown in the figure, so that the raw water flowing into the activated carbon filter 15 flows into the second watering line L4 before coming into contact with the activated carbon in the column.

[0029] Furthermore, if sufficient watering effect can be obtained on the raw water tank 11, the number of watering means (spray balls) for the raw water tank 11 may be as few as one. In other words, either one of the spray balls 21 or 22 may be omitted. Alternatively, either one of the watering lines L3 or L4 may be omitted altogether. However, in this case, even if air accumulates in the upper space within the columns of the water softener 14 and the activated carbon filter 15, the column on the side where the watering lines L3 and L4 are omitted cannot discharge the accumulated air to the outside. On the other hand, from a cost perspective, it is also conceivable to merge the two watering lines L3 and L4 into one and connect it to the raw water tank 11, but in this case as well, the back pressure in the merged line will increase, and there is a possibility that air may flow from the water softener 14 to the activated carbon filter 15 instead of to the raw water tank 11. Therefore, either the spray ball 21 or 22 may be omitted, but from the viewpoint of suppressing air stagnation in the upper space within the column, it is preferable that the water spray lines L3 and L4 be connected to both the water softener 14 and the activated carbon filter 15. If either the spray ball 21 or 22 is omitted, the water spray line L3 or L4 on the omitted side may be connected to a drain line (not shown) for discharging stagnant air to the outside, rather than to the raw water tank 11.

[0030] (Second embodiment) Figure 2 is a schematic diagram of a pure water production apparatus according to a second embodiment of the present invention. This embodiment differs from the first embodiment in that the position of the water softener has been changed.

[0031] This embodiment differs from the first embodiment in that the water softener 14 is installed not in the water supply line L1, but in the raw water supply line L2 (specifically, upstream of the on-off valve, not shown). That is, in this embodiment, since the water softener 14 is installed in a position outside the hot water circulation path including the water supply line L1, hot water is not passed through the first spray line L3 to the water softener 14 during the hot water sterilization process, and hot water is not sprayed by the spray ball 21. In this way, in this embodiment, since the water softener 14 is excluded from the hot water sterilization treatment, the lifespan of the ion exchange resin in the water softener 14 can be extended, and the time required for the hot water sterilization process can be shortened. In this embodiment as well, either the spray line L3 or L4 may be omitted, but in particular, the first spray line L3, through which hot water is not passed during the hot water sterilization process, may be omitted. The other configurations and effects of this embodiment are the same as those of the first embodiment. [Explanation of Symbols]

[0032] 10 Pure water production equipment 11 Raw water tank 12 Water supply pump 13 Heat exchanger 14. Water softener (pretreatment means) 15. Activated carbon filter (pretreatment means) 16 Water treatment equipment L1 Water supply line L2 Raw Water Supply Line L3 First watering line (connection line) L4 Second watering line (connection line) L5 Pure Water Line L6 Pure Water Return Line V1, V2 Shut-off valves CV1, CV2 Flow control valve (flow control means)

Claims

1. A tank for storing the water to be treated, A pretreatment means for performing pretreatment of the water to be treated, A water treatment system having a connection line that is connected to the upper part of the pretreatment means on the upstream side and to the upper part of the tank on the downstream side.

2. The water treatment system according to claim 1, further comprising a watering means provided at the downstream end of the connection line located inside the tank, for spraying the water to be treated flowing from the pretreatment means into the connection line into the inside of the tank.

3. The aforementioned pretreatment means has a tower-shaped container having an inlet for the water to be treated, The water treatment system according to claim 2, wherein the upstream side of the connection line is connected to the upper part of the container near the inlet of the water to be treated.

4. The aforementioned pretreatment means is a water softener in which an ion exchange resin is filled into the container, The water treatment system according to claim 3, wherein the water softener is provided upstream of the activated carbon filter.

5. The water treatment system according to claim 3, wherein the pretreatment means is an activated carbon filter in which activated carbon is filled into the container.

6. A water treatment system according to any one of claims 1 to 5, further comprising a flow rate adjustment means for adjusting the flow rate of water to be treated flowing through the aforementioned connection line.

7. A water treatment system according to any one of claims 1 to 5, used for producing pure water for use in pharmaceutical manufacturing.

8. The process involves storing the treated water in a tank, A step of pre-treating the water to be treated by passing it through a pre-treatment means before or after it is stored in the tank, A water treatment method comprising the step of allowing a portion of the water to be treated supplied to the pretreatment means to flow into the tank through a connecting line that connects the upper part of the pretreatment means and the upper part of the tank.

9. The water treatment method according to claim 8, wherein the step of introducing a portion of the water to be treated includes spraying a portion of the water to be treated into the inside of the tank.

10. The water treatment method according to claim 8 or 9, wherein the step of introducing a portion of the water to be treated includes adjusting the flow rate of the water to be treated flowing through the connection line.

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