drinking water supply system

Abstract

To provide a potable water supply system using the antimicrobial activity of silver, capable of suitably maintaining sanitary management for a long time.SOLUTION: A potable water supply system 1 is provided with water supply pipelines 2, 2A, 2B, 2C, 2D for supplying raw water W, and a pretreatment filter 3, a booster pump 4, a flow meter 5, a pair of mineral-adding modules 6, and a water cleaning filter 7 employing silver doped activated carbon, sequentially disposed between the water supply pipeline 2 and an ejection unit 8 attached to the end of the water supply pipeline 2D. The water cleaning filter 7 is constituted of a filter medium made from silver-doped fibrous activated carbon held between a precision filtration membrane or an ultrafiltration membrane and a nonwoven fabric, for example. A mechanism 9 of adding sodium hypochlorite, incorporating a mechanism of adding sodium chloride and comprising a chemical injection pump 10, is connected to the water supply pipeline 2 on the upstream of the pretreatment filter 3.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a drinking water supply system, and more particularly to a drinking water supply system that utilizes the antibacterial properties of silver, which allows for the maintenance of good hygiene over a long period of time. [Background technology]

[0002] Drinking water supply systems that produce drinking water using demineralized water such as distilled water or pure water as raw water and supply it by adding minerals as necessary are widely used in ships, restaurants, lodging facilities, and ordinary homes. In such drinking water supply systems, it is known that dissolving silver ions into treated water from a water purifier is effective in terms of antibacterial properties. Therefore, to prevent the growth of bacteria and other microorganisms within the system, a technology has been proposed that uses silver-coated activated carbon to dissolve silver ions into the treated water and control the number of general bacteria (Patent Documents 1 and 2). Furthermore, currently commercially available water purifiers use silver-coated activated carbon, and when using tap water as raw water, the concentration of impregnated silver is adjusted so that silver ions are eluted at a concentration of 50 μg / L immediately after the start of use. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2018-171577 [Patent Document 2] Japanese Patent Application Laid-Open No. 2013-56833 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in drinking water supply systems such as water purifiers that use this silver-plated activated carbon, even if the system is adjusted to elute silver ions at a concentration of 50 μg / L immediately after the start of use, excessive silver ions will elute from the silver-plated activated carbon, not only shortening the replacement life of the element using the silver-plated activated carbon, but also causing the problem that at the end of the replacement life, almost no silver ions will be eluted, which may result in insufficient antibacterial properties.

[0005] The present invention has been made in consideration of the above-mentioned problems, and aims to provide a drinking water supply system that utilizes the antibacterial properties of silver, making it possible to maintain sanitary management in an appropriate manner for a long period of time. [Means for solving the problem]

[0006] In order to achieve the above object, the present invention provides a drinking water supply system that treats desalinated water with a filter using silver-coated activated carbon, and that is equipped with a chloride ion addition mechanism in the upstream stage of the filter using silver-coated activated carbon (Invention 1).

[0007] This invention (Invention 1) provides a drinking water supply system capable of maintaining sanitary control through the antibacterial effect of silver for a long period of time. This is due to the following reasons. Specifically, the inventors investigated the causes of excessive silver ion elution from silver-coated activated carbon and found that when demineralized water such as distilled water or pure water is used as the raw water, excessive silver ions are eluted, resulting in almost no silver ions being eluted at the end of the filter's lifespan. The amount of silver ions eluted depends on the solubility product of silver chloride. Tap water in Japan contains chloride ions at concentrations between 10 mg / L and 200 mg / L (the upper limit of drinking water standards). In this case, the silver ions are dissolved in a controlled manner. For example, if a filter has a lifespan of 15,000 L, a silver concentration of 50 μg / L can be observed at the beginning and a few μg / L at the end of the filter's lifespan. This consistent elution of silver ions into the water from the beginning to the end maintains the sanitary condition of the water. However, when demineralized water such as distilled water or pure water is used as the raw water, almost no chloride ions are present. It was found that when the amount of chloride ions decreases, the solubility of silver chloride increases, and a high concentration of silver ions is eluted in the early stages, making it impossible to ensure an effective silver ion concentration at the end of the filter's life.Therefore, by installing a chloride ion addition mechanism in the front stage of the filter using silver-coated activated carbon and supplying water containing a certain concentration of chloride ions to the filter using silver-coated activated carbon, it is possible to control the amount of silver ions eluted.

[0008] In the above invention (Invention 1), it is preferable that the chlorine ion adding mechanism is attached to a free chlorine agent sterilization device (Invention 2).In the above inventions (Inventions 1 and 2), it is preferable that the filter using the silver-plated activated carbon is an ultrafiltration membrane or a microfiltration membrane with silver-plated activated carbon interposed therebetween (Invention 3).

[0009] According to such inventions (Inventions 2 and 3), a chlorine ion sterilization device is provided that can supply water containing a certain concentration of chlorine by mixing sodium hypochlorite in front of a filter such as an ultrafiltration membrane or microfiltration membrane carrying silver-coated activated carbon, and by dissolving salt together with the chlorine-based chemicals such as sodium hypochlorite that are injected into the device, chlorine ions can be present in the raw water, thereby controlling the elution of silver.

[0010] In the above inventions (Inventions 1 to 3), it is preferable to provide a mineral addition mechanism in the upstream stage of the filter using the silver-coated activated carbon (Invention 4).

[0011] According to this invention (Invention 4), drinking water that tastes like mineral water can be supplied.

[0012] In the above inventions (Inventions 1 to 4), it is preferable that the filter using the silver-coated activated carbon be backwashable (Invention 5).

[0013] According to this invention (Invention 5), by periodically backwashing a filter using silver-plated activated carbon with an ultrafiltration membrane or the like with water containing a free chlorine agent, it is possible to prevent bacterial growth on the secondary side of the filter.

[0014] In the above inventions (Inventions 1 to 5), it is preferable to provide a notification mechanism that notifies the user when it is time to replace the filter using the silver-coated activated carbon, whether backwashing is necessary, and / or when it is time to replace the chloride ion addition mechanism (Invention 6).

[0015] According to this invention (Invention 6), the system can be operated optimally by notifying the user of the timing of various maintenance and inspections using a notification mechanism such as an alarm lamp. [Effects of the Invention]

[0016] According to the drinking water supply system of the present invention, by providing a chloride ion addition mechanism in front of the filter using silver-coated activated carbon, water containing a certain concentration of chloride ions can be supplied to the filter using silver-coated activated carbon, thereby controlling the amount of silver ions eluted, and thereby enabling hygiene management through the antibacterial action of silver to be maintained appropriately for a long period of time. [Brief explanation of the drawings]

[0017] [Figure 1] 1 is a schematic diagram showing a drinking water supply system according to a first embodiment of the present invention; [Figure 2] 2 is a schematic diagram showing the flow of water when supplying drinking water in the drinking water supply system according to the embodiment. FIG. [Figure 3] 3 is a schematic diagram showing the flow during backwashing of the water purification filter of the drinking water supply system according to the embodiment. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0018] Hereinafter, one embodiment of the drinking water supply system of the present invention will be described in detail with reference to FIGS.

[0019] [Drinking water supply system] Fig. 1 shows a drinking water supply system according to one embodiment of the present invention. In Fig. 1, drinking water supply system 1 comprises water supply pipes 2, 2A, 2B, 2C, and 2D that supply raw water W (demineralized water such as distilled water or pure water), and a discharge section 8 equipped with a faucet or similar opening and closing mechanism at the end of each pipe. A pretreatment filter 3, a booster pump 4, a flow meter 5, a mineral addition module 6, and a water purification filter 7 using silver-coated activated carbon and an ultrafiltration membrane are sequentially arranged between the supply pipes.

[0020] The mineral addition module 6 is filled with a solid powder mineral agent, which can be derived from rocks or natural sources, and calcium components such as uncalcined shell calcium or uncalcined coral calcium are suitable.

[0021] The water purification filter 7 is, for example, a filter material made of fibrous activated carbon impregnated with silver ions, held between a microfiltration membrane or ultrafiltration membrane and a nonwoven fabric, and a fibrous filter to which, for example, silver zeolite is added other than the fibrous activated carbon can also be used. In this embodiment, a filter material made of fibrous activated carbon impregnated with silver ions, held between an ultrafiltration membrane and a nonwoven fabric, is used.

[0022] A sodium hypochlorite addition mechanism 9 serving as a free chlorine disinfectant addition mechanism is connected to the water supply pipe 2 upstream of the pretreatment filter 3. In this embodiment, the sodium hypochlorite addition mechanism 9 is configured such that a sodium hypochlorite solution tank (not shown) is filled with a sodium chloride aqueous solution of a predetermined concentration, and sodium hypochlorite is dissolved in the sodium chloride aqueous solution at a predetermined concentration. The sodium hypochlorite solution is added by a chemical feed pump 10 such as a diaphragm pump, thereby functioning as a chlorine ion addition mechanism.

[0023] Furthermore, a carbon dioxide gas supply pipe 21 equipped with a regulator 22A that is in communication with a carbon dioxide gas (CO2) source 22 is connected to the upstream side of the mineral addition module 6 and the downstream side of the flowmeter 5. Note that 23 and 24 are pressure switches, 25 and 26 are solenoid valves, and 27 is a check valve. The carbon dioxide gas supply pipe 21, carbon dioxide gas (CO2) source 22, regulator 22A, pressure switches 23 and 24, solenoid valves 25 and 26, and check valve 27 constitute a carbon dioxide gas dissolving mechanism.

[0024] Further, a three-way valve 31 connected to a branch pipe 32 communicating with the discharge section 8 is provided downstream of the connection point of the carbon dioxide gas supply pipe 21, making it possible to switch the water flow direction between the mineral addition module 6 side and the branch pipe 32 side. Furthermore, a drain pipe 41 is connected to the water supply pipe 2 between the mineral addition module 6 and the water purification filter 7. Note that 51 and 52 are solenoid valves, and 53, 54, 55, and 56 are check valves.

[0025] In the drinking water supply system 1 as described above, the flow meter 5 is connected to an arithmetic and control device (not shown) such as a personal computer, and is capable of sending a pulse signal to the arithmetic and control device at every fixed flow rate. The arithmetic and control device counts the cumulative flow rate of the raw water W and controls the carbon dioxide dissolution mechanism, and is also capable of notifying the user by notification means (not shown) such as a lamp, buzzer, or display when it is time to replace the water purification filter 7, whether backwashing is required, and when maintenance should be performed on the sodium hypochlorite addition mechanism 9.

[0026] [Operation method of drinking water supply system] A method of operating the drinking water supply system 1 of this embodiment having the above-described configuration will be described below.

[0027] <Drinking water production process> First, as shown in Figure 2, the three-way valve 31 is closed on the branch pipe 32 side and open on the mineral addition module 6 side, and the solenoid valve 52 is closed. As a result, the water supply pipe 2 forms a water passage that runs from the pre-treatment filter 3 through the mineral addition module 6 and the water purification filter 7 to the discharge part 8. In Figure 2, water does not flow through the branch pipe 32 and the drain pipe 41, so they are shown by dashed lines for convenience.

[0028] (Preparation and addition process of sodium hypochlorite for sterilization) When raw water W is supplied from the water supply pipe 2, the sodium hypochlorite addition mechanism 9 injects a sterilizing sodium hypochlorite solution, in which sodium chloride is dissolved, into the raw water W from the chemical injection pump 10. The chemical injection pump 10 is operated in response to a flow rate signal, so that it can add a stable concentration even when the water does not flow continuously.

[0029] The sodium hypochlorite concentration in this sodium hypochlorite solution for sterilization is about 0.1 to 10% by weight in terms of effective chlorine concentration, depending on the amount injected into the raw water W. If the effective chlorine concentration is less than 0.1% by weight, the sterilization effect is too low and a larger amount must be added to the raw water W, while if it exceeds 10% by weight, a larger amount of sodium hypochlorite is required, which reduces the ease of handling of the sodium hypochlorite addition mechanism 9. In particular, an effective chlorine concentration of about 0.5 to 5% by weight is preferred.

[0030] Furthermore, the amount of sodium chloride dissolved in the sterilizing sodium hypochlorite solution is about 1 to 30% by weight, depending on the amount injected into the raw water W. If the sodium chloride concentration is less than 1% by weight, the effect of suppressing silver elution in the water purification filter 7 using silver-coated activated carbon, which will be described later, is insufficient, while if it exceeds 50% by weight, the amount of sodium chloride required increases, reducing the ease of handling of the sodium hypochlorite addition mechanism 9. In particular, it is preferable that the sodium chloride concentration be about 5 to 20% by weight.

[0031] The sodium hypochlorite solution for sterilization in which sodium chloride is dissolved as described above is preferably added to the raw water W so that the free residual chlorine concentration in the raw water W is 0.5 to 5 mg / L, particularly 1 to 3 mg / L. - It is preferable to add it so that the concentration is 5 to 50 mg / L, particularly 10 to 30 mg / L.

[0032] (turbidity removal process) The raw water W to which the sterilizing sodium hypochlorite solution in which sodium chloride is dissolved is added is treated with a pretreatment filter 3 to remove fine particles and suspended matter. At this time, by making the housing of the pretreatment filter 3 have a predetermined volume or more, the raw water W is retained in this housing, thereby reducing fluctuations in the residual chlorine concentration.

[0033] (Mineral ingredient addition process) After the raw water W is treated by the pretreatment filter 3 to remove fine particles and suspended solids, the solenoid valve 25 is opened and the solenoid valve 26 is closed. The booster pump 4 is driven to pressurize the raw water W, and the flow rate is measured by the flow meter 5. When the raw water W reaches a set cumulative flow rate, the solenoid valve 26 is opened and carbon dioxide gas from the carbon dioxide gas source 22 is mixed and dissolved into the raw water W. This produces carbon dioxide-dissolved water with a controlled carbon dioxide concentration. By controlling the carbon dioxide gas concentration in the raw water W to be approximately 100 to 500 ppm, the bicarbonate hardness component concentration in the bicarbonate hardness component-containing water can be adjusted to a desired concentration in the mineral addition module 6, which will be described later.

[0034] The raw water W with dissolved carbon dioxide then reaches the three-way valve 31. At this time, the three-way valve 31 closes the branch pipe 32 and opens the mineral addition module 6, allowing the raw water W to flow from the water supply pipe 2A into the mineral addition module 6. As the raw water W passes through the mineral addition module 6, calcium in the mineral agent in the mineral addition module 6 dissolves as calcium bicarbonate in proportion to the carbon dioxide concentration due to the dissolution of carbon dioxide. If other mineral components are present, they also dissolve as bicarbonates. In particular, using uncalcined shell calcium or uncalcined coral calcium as a solid powdered mineral agent dissolves not only calcium carbonate but also magnesium carbonate, allowing mineral water containing these components to be obtained. The flow rate of the raw water W with dissolved carbon dioxide can be set so that the mineral water has the desired total hardness after passing through the mineral addition module 6. However, if the total hardness of the mineral water exceeds 100 mg / L, the mineral components are more likely to precipitate, so the mineral addition module 6 is filled with mineral components so that the total hardness is approximately 100 mg / L, or at most 200 mg / L.

[0035] (Silver ion addition process) By passing raw water W, to which minerals have been added, through a water purification filter 7 using fibrous activated carbon impregnated with silver ions, the added minerals remove organic matter, unpleasant flavors, and turbidity from the raw water W, while the silver ions further impart antibacterial properties. This silver-coated activated carbon is kneaded with, for example, silver chloride (AgCl). Although silver chloride is insoluble, the raw water W is demineralized water, such as distilled water or pure water, so ionic components other than Ag are very low. It is known that when other ionic components are low, a large amount of silver (1.55 mg / L) dissolves. This large amount of silver elution not only shortens the replacement life of elements using silver-coated activated carbon, but also causes almost no silver ion elution at the end of the replacement life, resulting in insufficient antibacterial properties. Strictly speaking, this silver elution is achieved at a dissolution equilibrium, where the rate of dissolution and the rate of precipitation are balanced. AgCl(solid)⇔Ag + (aq)+Cl - (aq)

[0036] If external influences cause changes in conditions such as concentration, pressure, or temperature, the equilibrium will shift in a direction that alleviates the change. This rule is called Le Chatelier's principle. When other ions are present in the solution, the solubility changes, transitioning to a solid state and precipitates. This can generally be expressed as the solubility product, and its Ksp is shown below. Ksp of AgCl = 1.77 x 10 -10 =[Ag+][Cl - ](moi 2 / L 2 )

[0037] When the product of ion concentrations exceeds the value of Kep, precipitation begins to occur. Here, assuming that the molecular weight of silver is 107.9 and that of chlorine (Cl) is 35.5, Ag + to the WHO guideline of 100 μg / L (= 9.26 × 10 -5 In order to keep the concentration of chloride ions below 1000 ppm (mol / L), the necessary chloride ion concentration can be calculated using the following formula: 1.77×10 -10 (moi 2 / L 2)÷9.26×10 -5 (mol / L) =1.923×10 -4 (mol / L) = 6.826 (mg / L)

[0038] Therefore, by adding a chloride salt (for example, NaCl) so that the chloride ion concentration is 7 mg / L or more, the silver ion concentration can be reduced to 100 μg / L or less.

[0039] Therefore, in this embodiment, by adding sodium chloride as described above in the process of adding sodium hypochlorite for sterilization, it is possible to impart antibacterial properties through silver ions while suppressing the elution of silver from the fibrous activated carbon to which silver ions are impregnated, thereby extending the life of the water purification filter 7.

[0040] <Cleaning process> Next, if the drinking water supply system 1 has been operated for a predetermined period of time or has been stopped for an extended period of time, the water purification filter 7 is cleaned and the accumulated water is discharged. For this cleaning, as shown in Figure 3, the three-way valve 31 is closed on the mineral addition module 6 side and open on the branch pipe 32 side, and the discharge part 8 is closed. This forms a water path that runs from the water supply pipe 2 through the pre-treatment filter 3 and the water purification filter 7 in the reverse direction to the drain pipe 41. Note that in Figure 3, water does not flow through the water supply pipes 2B and 2C, so they are shown by dashed lines for convenience.

[0041] Then, raw water W is supplied from the water supply pipe 2. At this time, the sodium hypochlorite addition mechanism 9 remains activated, and the solenoid valve 26 of the carbon dioxide supply pipe 21 is closed. The booster pump 4 is driven to pump the raw water W. As a result, the raw water W, which has been made bactericidal by the addition of sodium hypochlorite, reaches the three-way valve 31. At this time, the three-way valve 31 closes the mineral addition module 6 side and opens the branch pipe 32 side. Therefore, the raw water W flows in the reverse direction from the branch pipe 32 through the water purification filter 7, which uses silver-plated activated carbon and an ultrafiltration membrane. Impurities and turbid components accumulated in the water purification filter 7 are discharged, and the raw water W can be discharged from the drain pipe 41 as drain water D. Furthermore, backwashing with the raw water W, which has been made bactericidal by the addition of sodium hypochlorite, simultaneously sterilizes the pathway and prevents bacterial growth on the secondary side of the water purification filter 7, which uses an ultrafiltration membrane.

[0042] It is preferable that such a cleaning process be controlled so as to prompt the drainage of the drain water D by backwashing, by flashing a lamp as a notification mechanism using a control mechanism (not shown) when the drinking water supply system 1 has been operated for a predetermined time, or before use in the morning using a timer. This backwashing may also be controlled so as to be performed automatically. Furthermore, a lamp may be lit to prompt inspection when maintenance is required, such as when it is time to replace the pretreatment filter 3 or the purification filter 7, or when the remaining amount of chemical agent in the sodium hypochlorite addition mechanism 9 is low.

[0043] After backwashing the water purification filter 7, it can be returned to the drinking water production process shown in Fig. 2. By backwashing the water purification filter 7 in this way, the inside of the pathway of the drinking water supply system 1 can be purified, the quality of the drinking water W1 can be maintained at a good level, and the life of the water purification filter 7 can be further extended.

[0044] The drinking water supply system 1 of the present invention has been described above based on the above embodiment, but the present invention is not limited to the above embodiment and can be implemented in various modifications. For example, the notification mechanism is not limited to a lamp, but may be an alarm, a display, or a combination of both. In addition, various chlorides that can supply chloride ions can be used, not limited to sodium chloride, as long as they do not have an adverse effect on the human body. Furthermore, the carbon dioxide gas dissolving device may supply not only carbon dioxide gas but also a mixture of other gas components. [Example]

[0045] The present invention will be further illustrated by the following specific examples.

[0046] [Example 1] (Raw Water W) For raw water W, city water was desalinated using a reverse osmosis membrane (RO membrane), then anions and cations were removed using a mixed-bed ion exchange device, organic matter was decomposed using an ultraviolet oxidation device, and ultrapure water was prepared by removing particulate matter using an ultrafiltration membrane (UF membrane).

[0047] (Preparation of sodium hypochlorite solution for sterilization) The diluted water was prepared by dissolving 340 g of salt in 2.7 L of the same ultrapure water as the raw water W, and 300 mL of Purax (a sodium hypochlorite solution manufactured by Oyalux Co., Ltd.) with an effective chlorine concentration of 6% was added to this diluted water, and the solution was stirred well to prepare a sodium hypochlorite solution for sterilization. This solution was then stored in the tank of the sodium hypochlorite addition mechanism 9.

[0048] (Sodium hypochlorite addition process for sterilization) Using the drinking water supply system 1 shown in Figure 2, raw water W was supplied from the water supply line 2, and a sodium hypochlorite solution containing added sodium chloride was injected into the raw water W from the sodium hypochlorite addition mechanism 9 using a diaphragm pump (manufactured by Iwaki) with the stroke adjusted to 50% and the pulse set to the maximum. This sodium hypochlorite solution was injected into the raw water W via a siphon stop check valve by outputting a pump operation signal for 3 seconds every time 1 L of water flow was counted by the signal from the flow meter 5 in the system 1. As a result, the raw water W contained 1.5 mg / L of free residual chlorine and 15 mg / L of Cl. - was added.

[0049] (turbidity removal process) The raw water to which a sterilizing sodium hypochlorite solution in which sodium chloride is dissolved has been added is treated with a pretreatment filter 3 to remove fine particles and suspended matter.

[0050] (Mineral ingredient addition process) Carbon dioxide gas was added from a carbon dioxide gas source 22 to the raw water W treated by the pretreatment filter 3, and then the water was passed through a mineral addition module 6 to add calcium bicarbonate as the total hardness component. The amount of carbon dioxide gas injected at this time was set to an amount that assumed a total hardness of 150 mg / L.

[0051] (Silver ion addition process) Next, the raw water W with added minerals is passed through a water purification filter 7 using fibrous activated carbon impregnated with silver ions, thereby imparting antibacterial properties with the silver ions, and further removing organic matter, impurities, and turbidity components that have become mixed into the raw water W due to the addition of minerals, thereby producing drinking water W1.

[0052] This drinking water W1 was discharged from the discharge part 8, and 500 mL of water was sampled every 2 minutes when the flow rate was 50 L, 1000 L, 5000 L, 10000 L, and 15000 L. The chlorine ions (Cl - ) concentration, silver ion (Ag +The HCl concentration, total hardness (TH), and free residual chlorine concentration (FAC) were measured. The drinking water W1 was also evaluated for taste (flavor) and general bacteria. The results are shown in Table 1. Similar measurements were also performed on the water remaining downstream of the water purification filter 7 (retained water) during each water flow, and the results are shown in Table 2.

[0053] Here, chloride ions (Cl - ) concentration and total hardness were measured by ion chromatography, and silver ion (Ag + The concentration of free residual chlorine was measured by ICP / MS, and the concentration of free residual chlorine was measured by the DPD method. For general bacteria, a Petri film made by 3M was used, and the number of colonies (n=2) was counted after 48 hours of incubation at 36°C using the first sample water at each flow rate.

[0054] In addition, when measuring stagnant water, the automatic backwash function is used to pass raw water W, to which sodium hypochlorite has been added, through the secondary side of the microfiltration membrane for one minute at 7:00 every morning, thereby activating the function to prevent back-contamination from the nozzle, and when operation is resumed that morning, the lamp flashes to encourage drainage until the water is replaced with mineral water, and the stagnant water is then sampled and measured.

[0055] In addition, chloride ions (Cl - ) concentration, silver ion (Ag + ) Concentration, flavor and general bacterial indexes are shown in Table 3.

[0056] [Table 1]

[0057] [Table 2]

[0058] [Table 3]

[0059] *)E:Excellent (very delicious) G: Good (delicious) F: Fair (not tasty, but not bad) NG: No Good (not good)

[0060] [Comparative Example 1] Drinking water W1 was produced in the same manner as in Example 1, except that the sodium hypochlorite solution for sterilization was prepared using ultrapure water instead of the sodium chloride aqueous solution. 500 mL of water was sampled every 2 minutes when the water flow rate was 1000 L, 5000 L, 10000 L, and 15000 L, and the silver ions (Ag + The concentration was measured in the same manner as in Example 1. The results are shown in Table 4.

[0061] [Table 4]

[0062] As is clear from Tables 1 to 4, in the drinking water supply system 1 of Example 1 in which sodium chloride was present in the sodium hypochlorite solution for sterilization, even if the amount of treated water increased, Cl - is controlled to 16.9-30.0 mg / L, and Ag + Even after 15,000 L of water was passed through, the Ag concentration was kept at 4.7 μg / L. + It was observed that the general bacteria count was maintained at 100 / L or less, and antibacterial properties were maintained for a long period of time. In contrast, in Comparative Example 1, where sodium chloride was not present, Ag + may exceed 100 μg / L, and after 10,000 L of water is passed, almost all of the Ag + was not observed. [Explanation of symbols]

[0063] 1. Drinking water supply system 2,2A,2B,2C,2D Water supply pipe 3 Pre-processing filters 4. Booster pump 5 Flow meter 6 Mineral Addition Module 7. Water purification filter using silver-coated activated carbon 8 Discharge part 9 Sodium hypochlorite addition mechanism 10 Chemical injection pump 21 Carbon dioxide supply pipe 22 Carbon dioxide (CO2) source 22A regulator 23,24 Pressure switch 25,26 Solenoid valve 27 Check valve 31 Three-way valve 32 Branch pipe 41 Drain piping 51,52 Solenoid valve 53, 54, 55, 56 Check valve W Raw Water W1 Drinking water D Drain water

Claims

1. A drinking water supply system that treats desalinated water with a filter using silver-coated activated carbon, A drinking water supply system equipped with a chloride ion addition mechanism in front of the filter using the silver-coated activated carbon.

2. 2. The drinking water supply system according to claim 1, wherein the chloride ion adding mechanism is attached to a free chlorine agent sterilization device.

3. 3. The drinking water supply system according to claim 1, wherein the filter using silver-plated activated carbon is an ultrafiltration membrane or a microfiltration membrane interposed with silver-plated activated carbon.

4. 4. The drinking water supply system according to claim 1, further comprising a mineral addition mechanism provided in front of the filter using silver-coated activated carbon.

5. 5. The drinking water supply system according to claim 1, wherein the filter using the silver-coated activated carbon is backwashable.

6. The drinking water supply system according to any one of claims 1 to 5, further comprising a notification mechanism for notifying the user of the time to replace the filter using the silver-plated activated carbon, whether backwashing is required, and / or when to replace the chloride ion addition mechanism.

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