Water treatment system, water treatment method, and water treatment module

Abstract

To provide a water treatment system and a water treatment method in which clogging of a filtration membrane is suppressed.SOLUTION: A water treatment system comprising: a filtration section including a filtration membrane configured to separate water to be treated into permeate and concentrate; a confluence section at which the water to be treated supplied to the filtration section and the concentrate extracted from the filtration section join together; and a control section configured to control transfer of the concentrate to the confluence section based on an index X of the water to be treated.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a water treatment system, a water treatment method, and a water treatment module. [Background technology]

[0002] Filtration devices that use filtration membranes are extremely effective at removing impurities from water, and are therefore used to produce pure water for industrial use and water for daily life. For example, Patent Document 1 describes a drinking water vending machine equipped with a reverse osmosis membrane type filtration device. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 3420202 Summary of the Invention [Problem to be solved by the invention]

[0004] In a filtration device using a filtration membrane, pressure is applied to the water (water to be treated) supplied to the filtration device to separate it into water that passes through the filtration membrane (permeated water) and water that does not pass through the filtration membrane (concentrated water). When the water being treated that comes into contact with the filtration membrane contains a large amount of bacteria and nutrients, such as domestic wastewater, the bacteria and nutrients in the water can cause fungal growth and decay, leading to clogging of the membrane surface. This clogging of the filtration membrane can lead to an earlier replacement period for the membrane. In view of the above circumstances, an object of the present disclosure is to provide a water treatment system, a water treatment method, and a water treatment module that can suppress clogging of a filtration membrane and achieve a longer life for the filtration membrane. [Means for solving the problem]

[0005] The means for solving the above problems include the following embodiments. <1> a filtration unit including a filtration membrane that separates the water to be treated into permeate and concentrated water; A confluence section where the water to be treated supplied to the filtration section and the concentrated water extracted from the filtration section are converged; A water treatment system comprising: a control unit that controls the transfer of concentrated water to the confluence unit based on an index X of the water to be treated. <2> The indicator X includes electrical conductivity. <1> The water treatment system according to claim 1. <3> The control unit controls the transfer of concentrated water to the confluence unit so that the electrical conductivity of the water to be treated is 2000 μS / cm or less. <2> The water treatment system according to claim 1. <4> Further provided is a discharge section that discharges the concentrated water extracted from the filtration section as waste water. <1> ~ <3> The water treatment system according to any one of claims 1 to 10. <5> a filtration step of separating the water to be treated into permeate and concentrated water using a filtration membrane; a mixing step of mixing the water to be treated with the concentrated water obtained in the filtration step; and a control step of controlling mixing of the water to be treated and the concentrated water based on an index X of the water to be treated. <6> The indicator X includes electrical conductivity. <5> The water treatment method according to claim 1. <7> The control step controls mixing of the water to be treated with the concentrated water so that the electrical conductivity of the water to be treated is 2000 μS / cm or less. <6> The water treatment method according to claim 1. <8> The method further includes a discharge step of discharging the concentrated water obtained in the filtration step as waste water. <5> or <6> The water treatment method according to claim 1. <9> <1> ~ <4> 10. A water treatment module comprising at least one selected from the group consisting of a filtration section, a confluence section, and a control section included in the water treatment system according to any one of claims 1 to 9. [Effects of the Invention]

[0006] According to the present disclosure, a water treatment system, a water treatment method, and a water treatment module are provided that can suppress clogging of a filtration membrane and achieve a longer life for the filtration membrane. [Brief explanation of the drawings]

[0007] [Figure 1] 1 is a conceptual diagram illustrating an example of the configuration of a water treatment system. [Figure 2] 1 is a conceptual diagram illustrating an example of the configuration of a water treatment system. [Figure 3] 1 is a conceptual diagram illustrating an example of the configuration of a water treatment system. DETAILED DESCRIPTION OF THE INVENTION

[0008] In the present disclosure, a numerical range indicated using "to" indicates a range that includes the numerical values ​​before and after "to" as the minimum and maximum values, respectively. In the numerical ranges described in stages in this disclosure, the upper or lower limit value described in a certain numerical range may be replaced by the upper or lower limit value of another numerical range described in stages, or may be replaced by a value shown in an example.

[0009] <Water treatment system> The water treatment system of the present disclosure comprises: a filtration unit including a filtration membrane that separates the water to be treated into permeate and concentrated water; A confluence section where the water to be treated supplied to the filtration section and the concentrated water extracted from the filtration section are converged; and a control unit that controls the transfer of concentrated water to the confluence based on an index X of the water to be treated.

[0010] According to the water treatment system of the present disclosure, clogging of the filtration membrane is effectively suppressed. Causes of clogging of filtration membranes include clogging of pores in filtration membranes by inorganic components such as calcium, and clogging of pores in filtration membranes by biofilms derived from organic matter. In the water treatment system of the present disclosure, the transfer of concentrated water to the confluence is controlled based on the index X of the water to be treated supplied to the filtration section. By controlling the transfer of concentrated water to the confluence based on the index X of the water to be treated, changes in the state of the water to be treated (such as an increase in microbial concentration) due to mixing with the concentrated water are less likely to occur. As a result, clogging of the pores of the filtration membrane by biofilms derived from microorganisms is less likely to occur, and the life of the filtration membrane is extended. Furthermore, in the water treatment system of the present disclosure, not only is the life of the filtration membrane extended, but a decrease in the amount of permeate and an increase in filtration pressure due to a decrease in the effective filtration area caused by the generation of biofilm are suppressed.

[0011] In this disclosure, "water to be treated" refers to the entire object of filtration in the filtration unit. "Raw water" refers to water to be treated that has not been mixed with concentrated water extracted from the filtration unit. That is, the concept of "water to be treated" in this disclosure includes raw water that has not been mixed with concentrated water and a mixture of raw water and concentrated water.

[0012] In the water treatment system of the present disclosure, the type of water to be treated is not particularly limited. For example, the water to be treated may include tap water, surface water, well water, rainwater, stored water stored in a tank or the like, and water discharged from household facilities.

[0013] Specific examples of water discharged from living facilities include water discharged from living facilities such as bathrooms, shower rooms, washbasins, kitchens, toilets, etc. The water discharged from living facilities may be in a state that has been subjected to biological treatment using microorganisms.

[0014] (filtration section) The water treatment system of the present disclosure includes a filtration unit including a filtration membrane that separates the water to be treated into permeate and concentrated water. In the water treatment system of the present disclosure, the configuration of the filtration unit is not particularly limited as long as it includes a filtration membrane. For example, the filtration unit may be a roll or stack of filtration membranes housed in a container. The filtration unit may include a mechanism for applying pressure to raw water supplied to the filtration unit, and the mechanism may be connected to an external power source.

[0015] The type of filtration membrane included in the filtration section is not particularly limited, and can be selected from pressure-filtered types such as reverse osmosis membranes (RO membranes), nanofiltration membranes (NF membranes), ultrafiltration membranes (UF membranes), and microfiltration membranes (MF membranes). From the viewpoint of impurity removal performance, reverse osmosis membranes and nanofiltration membranes are preferred as filtration membranes, with reverse osmosis membranes being more preferred.

[0016] (Confluence) The water treatment system of the present disclosure includes a confluence section where the water to be treated supplied to the filtration section and the concentrated water extracted from the filtration section are joined together. That is, the water treatment system of the present disclosure does not simply discard the concentrated water extracted from the filtration unit, but is equipped with a mechanism for filtering the concentrated water again as water to be treated. In the present disclosure, a water treatment system including a mechanism for filtering the concentrated water extracted from the filtration unit again as water to be treated is also referred to as a "circulation-type water treatment system." In other words, the water treatment system of the present disclosure is a circulation-type water treatment system.

[0017] In the water treatment system of the present disclosure, the configuration of the confluence section is not particularly limited as long as it can confluence the concentrated water with the water to be treated. For example, the confluence section may be a tank that can store the water to be treated therein, a pipe through which the water to be treated can flow, or the like.

[0018] In the water treatment system of the present disclosure, the configuration of the confluence section is not particularly limited as long as the water to be treated and the concentrated water can be combined. For example, the confluence section may be a tank, a pipe, or the like where the water to be treated and the concentrated water can come into contact with each other.

[0019] (Control unit) The water treatment system of the present disclosure includes a control unit that controls the supply of concentrated water to the confluence based on the index X of the water to be treated.

[0020] Recirculating water treatment systems have a high recovery rate of permeate (the ratio of permeate to treated water) obtained in the filtration section, making them highly efficient at saving water. However, recirculating water treatment systems tend to allow organic matter from concentrated water to accumulate in the treated water. This makes it easy for biofilms from microorganisms that use organic matter as a nutrient source to form, causing blockages in the filtration membrane. The water treatment system of the present disclosure controls the supply of concentrated water to the confluence based on the index X of the water to be treated. In the water treatment system of the present disclosure, the method for controlling the supply of concentrated water to the confluence by the control unit is not particularly limited. For example, the amount of concentrated water transferred to the confluence, the timing of transfer of the concentrated water to the confluence, etc. may be included as objects of control. The means by which the control unit controls the supply of concentrated water to the confluence is not particularly limited. For example, the control unit may control the supply of concentrated water by opening and closing a valve (such as an electromagnetic valve) provided in a pipe that transports the concentrated water.

[0021] The index X of the water to be treated, which serves as a basis for control by the control unit, is not particularly limited. Suitable indexes X in the water treatment system of the present disclosure include electrical conductivity, bacterial count, color, turbidity, odor level, and viscosity, and among these, electrical conductivity is preferred. The index X of the water to be treated, which is the basis for control by the control unit, may be one or a combination of two or more.

[0022] The control unit may have a function of monitoring the index X of the water to be treated. The method for monitoring the index X of the water to be treated is not particularly limited and can be carried out by a known method. For example, monitoring may be carried out by installing an index X measuring device (e.g., an electrical conductivity measuring device) in a tank that stores the water to be treated or in a pipe through which the water to be treated flows.

[0023] The control unit may have a function of controlling the discharge of the concentrated water extracted from the filtration unit as waste water. By controlling the discharge of the concentrated water as waste water, the amount of concentrated water supplied to the confluence unit can be indirectly controlled. For example, if the index X of the water to be treated is below (or above) a set standard, the amount of concentrated water supplied to the confluence may be increased without discharging the concentrated water, and if the index X of the water to be treated is above (or below) a set value, the concentrated water may be discharged and the amount of concentrated water supplied to the confluence may be reduced.

[0024] The control unit may control the supply of concentrated water to the confluence unit so that the electrical conductivity of the water to be treated is 2000 μS / cm or less. By controlling the supply of concentrated water to the confluence so that the electrical conductivity of the treated water is 2000 μS / cm or less, the condition of the treated water supplied to the filtration section (especially the concentration of microorganisms and organic matter) is maintained in a good condition, and clogging of the filtration membrane is effectively suppressed. From the viewpoint of maintaining a good condition of the water to be treated supplied to the filtration section, the control unit may control the supply of concentrated water to the confluence section so that the electrical conductivity of the water to be treated is 1500 μS / cm or less, or may control the supply of concentrated water to the confluence section so that it is 1200 μS / cm or less, or may control the supply of concentrated water to the confluence section so that it is 1000 μS / cm or less.

[0025] In the water treatment system of the present disclosure, the control of the supply of concentrated water to the confluence may be performed for each water treatment module of the present disclosure described below, for each water treatment system equipped with a water treatment module, or for multiple water treatment systems together. In the water treatment system of the present disclosure, the steps of removing the concentrated water from the filtration section, supplying the concentrated water to the confluence section, and discharging the concentrated water as waste water may be performed manually or automatically.

[0026] (Discharge section) The water treatment system of the present disclosure may include a discharge section that discharges the concentrated water removed from the filtration section as waste water. In the water treatment system of the present disclosure, the configuration of the discharge unit is not particularly limited as long as it is capable of discharging the concentrated water as waste water. For example, the discharge unit may be a tank or pipe equipped with an outlet for the concentrated water.

[0027] The confluence part where the concentrated water meets the water to be treated and the discharge part where the concentrated water is discharged as waste water may be connected to each other or may be independent of each other. For example, the water treatment system of the present disclosure may include a transfer line having a branched structure into transfer line A, which transfers concentrated water extracted from the filtration section to the confluence section, and transfer line B, which discharges the concentrated water as waste water, or may include transfer line A and transfer line B independently. When the confluence and the discharge part are connected to each other, a switching valve for switching the destination of the concentrated water (the confluence or the discharge part) may be disposed between the confluence and the discharge part.

[0028] (Pre-filtration section) The water treatment system of the present disclosure may further include a preliminary filtration section that filters the water to be treated. By providing a preliminary filtration section that filters the water to be treated in a water treatment system, impurities contained in the water to be treated that is supplied to the filtration section can be more effectively removed, and clogging of the filtration membrane can be more effectively prevented. The configuration of the pre-filtration section is not particularly limited and can be selected depending on the state of the water to be treated, the state of foreign matter and impurities contained in the water, etc. For example, the pre-filtration section can be made of one or a combination of two or more selected from known materials such as sand, cellulose, porous synthetic resin, polymer fibers such as nonwoven fabric, activated carbon, zeolite, ceramics, and filtration membranes.

[0029] The location where the preliminary filtration unit is provided in the water treatment system is not particularly limited as long as it is a location where the water to be treated can be filtered (that is, a location upstream of the filtration unit). When the water treatment system includes a confluence between the contact section and the filtration section, the pre-filtration section may be located upstream of the confluence or downstream of the confluence, but is preferably located upstream of the confluence. Examples of cases in which the preliminary filtration section is located upstream of the confluence section include when the preliminary filtration section is located between the contact section and the confluence section, and when the preliminary filtration section is located upstream of the contact section (for example, between the contact section and a raw water tank that stores raw water to be supplied to the contact section). An example of a case where the pre-filtration section is disposed downstream of the confluence section is a case where the pre-filtration section is disposed between the confluence section and the filtration section. The number of preliminary filtration units arranged in the water treatment system may be one or two or more. The type of pre-filtration unit arranged in the water treatment system may be one type or two or more types.

[0030] (Finishing filtration section) The water treatment system of the present disclosure may further include a finishing filtration section that filters the permeated water obtained in the filtration section. By providing the permeated water obtained in the filtration section, impurities contained in the permeated water can be removed more reliably. The configuration of the finishing filtration section is not particularly limited and can be selected depending on the state of the permeate, the state of foreign matter and impurities contained in the permeate, etc. For example, the finishing filtration section can be made of one or a combination of two or more materials selected from known materials such as sand, cellulose, porous synthetic resin, polymer fibers such as nonwoven fabric, activated carbon, zeolite, ceramics, and filtration membranes.

[0031] The position where the finishing filtration unit is provided in the water treatment system is not particularly limited as long as it is a position where the permeated water can be filtered (that is, a position downstream of the filtration unit). The number of polishing filtration units arranged in the water treatment system may be one or two or more. The number of types of finishing filtration units arranged in the water treatment system may be one or two or more.

[0032] (Sterilization Processing Unit) The water treatment system of the present disclosure may include a sterilization treatment unit that performs sterilization treatment on the water to be treated. In the present disclosure, subjecting the water to a sterilization treatment is also referred to as a "sterilization treatment." By sterilizing the water to be treated, it is possible to kill microorganisms contained in the water or control the concentration of microorganisms to a predetermined level, thereby effectively suppressing clogging of the filtration membrane due to the formation of biofilms derived from microorganisms. The sterilization treatment performed by the sterilization treatment unit includes, for example, treatment in which the water to be treated is exposed to ultraviolet (UV) rays or ozone. When sterilization treatment is performed using ozone, a decolorization effect on the water to be treated can also be expected.

[0033] In the water treatment system of the present disclosure, the configuration of the sterilization treatment unit is not particularly limited as long as it can perform sterilization treatment of the water to be treated. For example, the sterilization treatment unit may be a tank, piping, etc. connected to a UV generator or an ozone generator. The treated water to be sterilized in the sterilization treatment unit may be in a state where it is not mixed with the concentrated water extracted from the filtration unit (i.e., raw water), or may be in a state where it is mixed with the concentrated water extracted from the filtration unit. The sterilization treatment unit may sterilize the water to be treated constantly or intermittently. Methods for the sterilization treatment unit to intermittently perform sterilization treatment of the water to be treated include, for example, setting a time for operating the sterilization treatment unit and operating the sterilization treatment unit at the set time, and operating the sterilization treatment unit when sterilization treatment becomes necessary due to fluctuations in the impurity concentration of the water to be treated.

[0034] (Other configurations) If necessary, the water treatment system of the present disclosure may further include other components in addition to the components described above. Other components that the water treatment system may include a raw water tank for storing raw water, instruments for water quality management, a computer system for controlling the operation of the water treatment system, piping for transporting the water to be treated, concentrated water, and permeated water, and valves (such as solenoid valves) for controlling the transport of the water to be treated, concentrated water, and permeated water. When the water treatment system includes a raw water tank (including when the raw water tank includes a water treatment module), the raw water tank may be directly connected to the contact unit or may be connected to the contact unit via a pipe. When the raw water tank is connected to the contact unit via a pipe, a filter may be disposed in the pipe. When a water treatment system is equipped with a computer system for controlling the operation of the water treatment system, the computer system may independently control the operation of one water treatment system or may collectively control the operation of multiple water treatment systems.

[0035] As one embodiment of the water treatment system of the present disclosure, an example of the configuration of a circulating water treatment system will be described with reference to the drawings. In each of the following figures, arrows indicate the flow direction of water before or after treatment. The configurations shown in each figure are examples, and the configuration of the water treatment system of the present disclosure is not limited to these.

[0036] A preferred embodiment of the water treatment system of the present disclosure is shown in FIG. The water treatment system 10 shown in FIG. a filtration unit 11 including a filtration membrane that separates the water to be treated into permeate and concentrated water; a tank 12 for storing the water to be treated that is supplied to the filtration unit 11; a measuring instrument 13 for measuring an index X of the water to be treated; and a transfer line 14 for transferring the concentrated water extracted from the filtration section 11.

[0037] In the water treatment system 10, the tank 12 that stores the water to be treated that is supplied to the filtration unit 11 corresponds to the confluence unit where the water to be treated and the concentrated water are confluent. Although not shown, the water treatment system 10 includes a control unit that controls the supply of concentrated water to the tank 12 based on the measured value of the index X of the water to be treated measured by the measuring device 13.

[0038] In the water treatment system 10, the transfer line 14 has a structure in which it branches into a transfer line 14A that transfers the concentrated water to the tank 12 and a transfer line 14B that discharges the concentrated water as waste water. 1 has a structure in which transfer line 14A and transfer line 14B are branched, but the configuration of the water treatment system of the present disclosure is not limited to this. For example, water treatment system 10 may be provided with a transfer line that transfers concentrated water to a tank and a transfer line that discharges concentrated waste water, which are independent of each other.

[0039] In the water treatment system 10, the operation of discharging the concentrated water extracted from the filtration unit 11 as waste water may include the following operations 1 and 2. When carrying out operations 1 and 2, the following operation 3 may be carried out. By carrying out operation 3, it is possible to promote the discharge of the concentrated water as waste water. However, operation 3 does not necessarily have to be carried out.

[0040] Operation 1: Stop the inflow of raw water into the tank 12. For example, close the valve provided at the raw water inlet of the tank 12. Operation 2: The concentrated water extracted from the filtration unit 11 is discharged as waste water. For example, a valve provided at the outlet of the transfer line 14B is opened. Operation 3: Stop the transfer of the concentrated water extracted from the filtration unit 11 to the tank 12. For example, close the valve provided on the transfer line 14A.

[0041] A preferred embodiment of the water treatment system of the present disclosure is shown in FIG. The water treatment system 20 shown in FIG. a filtration unit 21 including a filtration membrane that separates the water to be treated into permeate and concentrated water; a tank 22 for storing the water to be treated that is supplied to the filtration unit 21; a measuring instrument 23 for measuring an index X of the water to be treated; and a transfer line 24 for transferring the concentrated water extracted from the filtration section 21.

[0042] In the water treatment system 20, the transfer line 24 has a branched structure into a transfer line 24A that transfers the concentrated water to a branch 25 and a transfer line 24B that discharges the concentrated water as waste water.

[0043] Water treatment system 20 differs from water treatment system 10 shown in Figure 1 in that the confluence where the water to be treated and the concentrated water join is not tank 22, but branch 25 provided in the piping connecting filtration section 21 and tank 22.

[0044] A preferred embodiment of the water treatment system of the present disclosure is shown in FIG. The water treatment system 30 shown in FIG. a filtration section 31 including a filtration membrane that separates the water to be treated into permeate and concentrated water; a tank 32 for storing the water to be treated that is supplied to the filtration unit 31; a measuring instrument 33 for measuring an index X of the water to be treated; a transfer line 34 for transferring the concentrated water extracted from the filtration unit 31; and a preliminary filtration section 36 for filtering the water to be treated. and a finishing filtration section 37 for filtering the permeated water.

[0045] Water treatment system 30 differs from water treatment system 20 shown in FIG. 2 in that it includes a preliminary filtration section 36 that filters the water to be treated and a finishing filtration section 37 that filters the permeated water. In the water treatment system 30, the preliminary filtration units 36 are provided between the tank 32 and the branch 35 and on the upstream side of the tank 32, respectively, but the configuration of the water treatment system of the present disclosure is not limited to this. For example, the preliminary filtration unit 36 ​​may be provided between the branch 35 and the filtration unit 31. Although the water treatment system 30 is provided with two pre-filtration units 36, the water treatment system may be provided with one pre-filtration unit 36 ​​or three or more pre-filtration units 36.

[0046] The operation of each element constituting the water treatment system of the present disclosure may be performed manually or automatically, or may be performed in a combination of manual and automatic modes. From the viewpoint of the operating costs of the water treatment system, it is preferable that the operation of each element constituting the water treatment system be at least partially automated.

[0047] The use of the permeate extracted from the water treatment system of the present disclosure is not particularly limited. Specific uses of the permeate include use in living facilities such as bathrooms, shower rooms, washbasins, kitchens, and toilets, use in industrial facilities such as factories and farms, use as water supply and sewage, and release into the natural environment. In one aspect of the water treatment system of the present disclosure, the permeate removed from the water treatment system may be utilized, and then the utilized permeate may be supplied to the water treatment system as raw water. From the viewpoint of cost-effectiveness in using the water treatment system, it is preferable that the permeate extracted from the water treatment system of the present disclosure be used in living facilities.

[0048] The water treatment system of the present disclosure, whether a circulating water treatment system or a water treatment module, can reduce operating costs by suppressing clogging of the filtration membrane. Therefore, the water treatment system of the present disclosure is excellent for effectively obtaining purified water and can be suitably used under limited conditions where the available water quality is poor, such as in areas with scarce water resources or disaster-stricken areas.

[0049] The scale of water treatment by the water treatment system of the present disclosure is not particularly limited. For example, the amount of water treated per day by the water treatment system of the present disclosure can be selected from the range of 100 mL to 50,000 L. When the water treatment system is used as a home water purifier, the scale of water treatment can be selected from the range of 100 mL to 50 L, for example. When the water treatment system is used as a household wastewater purification device, the scale of water treatment can be selected from the range of 1 L to 1,000 L, for example. When the water treatment system is used as a relatively large-scale water treatment device such as a device for purifying rainwater stored in a rooftop tank, the scale of water treatment can be selected from the range of 100 L to 50,000 L, for example. The water treatment system of the present disclosure can also be suitably used for producing permeate under conditions where the scale of water treatment is small and the supply amount of water to be treated is limited.

[0050] <Water treatment method> The water treatment method of the present disclosure includes: a filtration step of separating the water to be treated into permeate and concentrated water using a filtration membrane; a mixing step of mixing the water to be treated with the concentrated water obtained in the filtration step; and a control step of controlling mixing of the water to be treated and the concentrated water based on the index X of the water to be treated.

[0051] According to the water treatment method of the present disclosure, clogging of the filtration membrane is effectively suppressed. In the water treatment method of the present disclosure, the filtration membrane used in the filtration step may be the filtration membrane used in the water treatment system of the present disclosure described above.

[0052] The water treatment method of the present disclosure includes a mixing step of mixing the concentrated water obtained in the filtration step with the water to be treated. That is, the water treatment method of the present disclosure is a circulating water treatment method. In a circulating water treatment method, organic matter derived from the concentrated water accumulates in the water to be treated, increasing the microbial concentration in the water to be treated, which may lead to a state where the filtration membrane is more susceptible to clogging. The water treatment method of the present disclosure includes a control step of controlling the mixing of the water to be treated with the concentrated water based on the index X of the water to be treated. Therefore, even if the water to be filtered contains concentrated water, the condition of the water to be treated is maintained in a good state, and clogging of the filtration membrane is effectively suppressed.

[0053] In the control step, the method for controlling the mixing of the water to be treated and the concentrated water is not particularly limited. For example, the amount of concentrated water to be mixed with the water to be treated, the timing of mixing the concentrated water with the water to be treated, etc. may be controlled.

[0054] The index X of the water to be treated, which serves as a control standard in the control step, is not particularly limited. Suitable index X in the water treatment method of the present disclosure includes electrical conductivity, bacterial count, color, turbidity, odor level, and viscosity, and among these, electrical conductivity is preferred. The index X of the water to be treated, which is the control standard in the control step, may be one or a combination of two or more. That's fine.

[0055] The control step may include monitoring the index X of the water to be treated. The method for monitoring the index X of the water to be treated is not particularly limited and can be carried out by a known method. For example, monitoring may be carried out by installing an index X measuring device (e.g., an electrical conductivity measuring device) in a tank that stores the water to be treated or in a pipe through which the water to be treated flows.

[0056] The control step may include controlling the discharge of the concentrated water removed from the filtration unit as waste water. By controlling the discharge of the concentrated water as waste water, the amount of concentrated water mixed with the water to be treated can be indirectly controlled. For example, if the index X of the water to be treated is below (or above) a set standard, the amount of concentrated water to be mixed with the water to be treated may be increased without discharging the concentrated water, and if the index X of the water to be treated is above (or below) a set value, the concentrated water may be discharged and the amount of concentrated water to be mixed with the water to be treated may be reduced.

[0057] In the control step, mixing of the water to be treated with the concentrated water may be controlled so that the electrical conductivity of the water to be treated is 2000 μS / cm or less. By controlling the mixing of the water to be treated with the concentrated water so that the electrical conductivity of the water to be treated is 2000 μS / cm or less, the condition of the water to be treated supplied to the filtration section (especially the concentration of microorganisms and organic matter) is maintained in a good condition, and clogging of the filtration membrane is effectively suppressed. From the viewpoint of maintaining a good condition of the water to be treated supplied to the filtration section, the control section may control the mixing of the water to be treated with concentrated water so that the electrical conductivity of the water to be treated is 1500 μS / cm or less, or may control the mixing of the water to be treated with concentrated water so that the electrical conductivity is 1200 μS / cm or less, or may control the mixing of the water to be treated with concentrated water so that the electrical conductivity is 1000 μS / cm or less.

[0058] In the water treatment method of the present disclosure, the control of the mixing of the water to be treated and the concentrated water may be performed for each water treatment system of the present disclosure described above or each water treatment module of the present disclosure described below, for each water treatment system equipped with a water treatment module, or for multiple water treatment systems together. In the water treatment method of the present disclosure, the steps of removing the concentrated water from the filtration section, mixing the concentrated water with the water to be treated, and discharging the concentrated water as waste water may be performed manually or automatically.

[0059] The water treatment method of the present disclosure may further include a discharge step of discharging the concentrated water obtained in the filtration step as waste water. In the discharge step, all of the concentrated water obtained in the filtration step may be discharged as waste water, or a portion of the concentrated water may be discharged as waste water. When a portion of the concentrated water is discharged as waste water, the concentrated water may be combined with the water to be treated.

[0060] The timing of discharging the wastewater in the discharging step may be determined based on the monitoring results of the index X of the water to be treated. For example, if the electrical conductivity of the water to be treated is below a set standard, the waste water may not be discharged, and if the electrical conductivity of the water to be treated is above a set value, the waste water may be discharged.

[0061] The water treatment method of the present disclosure may further include a pre-filtration step of filtering the water to be treated. The method for performing the pre-filtration step is not particularly limited and can be selected depending on the state of the water to be treated, the state of foreign matter and impurities contained in the water, etc. The pre-filtration step can be carried out, for example, by the pre-filtration section that may be included in the water treatment system described above.

[0062] The method for carrying out the water treatment method of the present disclosure is not particularly limited. For example, the method may be carried out using the water treatment system of the present disclosure described above.

[0063] <Water treatment module> The water treatment module of the present disclosure comprises: The water treatment system includes at least one selected from the group consisting of a filtration section, a confluence section, and a control section. In this disclosure, a water treatment module refers to a component or combination of components for use in a water treatment system. The water treatment module of the present disclosure is not particularly limited as long as it can be used in the water treatment system of the present disclosure, and may be an independent component that is connected to an existing filtration device, water treatment device, or water distribution pipe. [Explanation of symbols]

[0064] 10, 20, 30: Water treatment systems 11, 21, 31: Filtration section 12, 22, 32: Tank 13, 23, 33: Measuring instrument 14, 24, 34: Transfer lines 25, 35: Branch 36: Pre-filtration section 37: Finishing filtration section

Claims

1. a filtration unit including a filtration membrane that separates the water to be treated into permeate and concentrated water; A confluence section where the water to be treated supplied to the filtration section and the concentrated water extracted from the filtration section are converged; A water treatment system comprising: a control unit that controls the transfer of concentrated water to the confluence based on an index X of the water to be treated.

2. The water treatment system of claim 1 , wherein the indicator X includes electrical conductivity.

3. The water treatment system according to claim 2 , wherein the control unit controls the transfer of the concentrated water to the confluence unit so that the electrical conductivity of the water to be treated is 2000 μS / cm or less.

4. The water treatment system according to claim 1 , further comprising a discharge section that discharges the concentrated water removed from the filtration section as waste water.

5. a filtration step of separating the water to be treated into permeate and concentrated water using a filtration membrane; a mixing step of mixing the water to be treated with the concentrated water obtained in the filtration step; and a control step of controlling mixing of the water to be treated and the concentrated water based on an index X of the water to be treated.

6. The water treatment method according to claim 5 , wherein the index X includes electrical conductivity.

7. 7. The water treatment method according to claim 6, wherein the control step controls mixing of the water to be treated with the concentrated water so that the electrical conductivity of the water to be treated is 2000 μS / cm or less.

8. The water treatment method according to claim 5 , further comprising a discharge step of discharging the concentrated water obtained in the filtering step as waste water.

9. A water treatment module comprising at least one selected from the group consisting of a filtration section, a confluence section, and a control section included in the water treatment system according to any one of claims 1 to 4.

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