How to operate a water treatment system

Abstract

To integrate only a water flow rate being a load of an ion exchange resin to optimize a timing of ion exchange resin regeneration.SOLUTION: An operational method for a water treatment system having an ion exchange resin apparatus for housing an ion exchange resin and return means for returning at least a part of ion exchange treatment water of the ion exchange resin apparatus to the upstream side of the ion exchange resin apparatus as return water, includes: a treated water passing step of passing raw water or treated water including mixed water of raw water and the return water to the ion exchange resin apparatus; and a regeneration step of regenerating the ion exchange resin in the ion exchange resin apparatus, wherein the regeneration step is performed when a load applied to the ion exchange resin by the raw water included in the treated water reaches a specified value.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a method for operating a water treatment system having an ion exchange resin device, and more particularly to a method for operating a water treatment system that can optimize the regeneration frequency of the ion exchange resin. [Background technology]

[0002] In facilities that produce treated water (deionized water) by passing raw water through an ion exchange resin tower, the cumulative flow rate is detected during the raw water passing process using an integrated flow meter (FIQ) attached to the treated water line, and control is performed to switch to the chemical regeneration process when the cumulative flow rate reaches a set value (constant volume).

[0003] Patent Document 1 describes that a flow meter built into the water softener accumulates the amount of treated make-up water passing through it, and when the accumulated amount reaches a predetermined amount based on the hardness of the make-up water, a cam switch outputs a regeneration operation signal, and the control unit counts the number of times the cation exchange resin has been regenerated and displays a regeneration salt shortage alarm using an alarm notification means.

[0004] Patent Document 2 describes that the device has means for detecting the electrical conductivity and the amount of water passing through, and that the device is regenerated when the calculated amount of ion exchange adsorption reaches a predetermined value. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Utility Model Registration No. 3118664 [Patent Document 2] Japanese Patent Application Publication No. 3-181384 Summary of the Invention [Problem to be solved by the invention]

[0006] In water treatment systems that include a raw water tank, an ion exchange tower (ion exchange resin tower), a treated water tank for ion-exchanged water, and downstream equipment to which treated water is supplied from the treated water tank, the system may be configured to return treated water to the raw water tank depending on the water level in the treated water tank. The downstream equipment maintains water quality by continuously circulating and treating the water, similar to a subsystem in a pure water production system. Brine is discharged from the downstream equipment, such as UF membranes, as downstream equipment wastewater. When needed at the point of use, treated water is withdrawn from the downstream equipment's circulation line (or directly from the treated water tank), lowering the water level in the treated water tank. The system controls the system to replenish the water tank. When the water level in the treated water tank is sufficiently high, treated water from the ion exchange tower is returned to the raw water tank. In either case, the ion exchange tower's feedwater, effluent, and return water are controlled to always maintain a constant flow rate above a certain level.

[0007] In a water treatment system like this, where treated water is returned to the raw water tank according to the water level in the treated water tank downstream of the ion exchange tower, an integrated flow meter (FIQ) installed in the treated water line detects the integrated flow rate and controls the system to switch to the chemical regeneration process when the integrated flow rate reaches a set value (constant volume). In this case, the treated water returned to the raw water tank does not place a load on the ion exchange resin, but in conventional systems, the returned treated water is included in the integrated flow rate. As a result, the load on the ion exchange resin is accumulated excessively, resulting in excessively frequent chemical regeneration.

[0008] In order to solve this problem, the present invention aims to optimize the timing of regeneration of the ion exchange resin by integrating only the flow rate of water that places a load on the ion exchange resin.

[0009] In Patent Document 1, regeneration and the like are performed using an integrated value and counting is also performed, but the case where the treated water is circulated is not taken into consideration. Similarly, Patent Document 2 does not consider the case where the treated water is circulated, and the electrical conductivity must be measured at the same time, and the configuration is limited. [Means for solving the problem]

[0010] The gist of the method for operating the water treatment system of the present invention is as follows.

[0011] [1] A method for operating a water treatment system having an ion exchange resin device containing ion exchange resin and a return means for returning at least a portion of the ion-exchange-treated water of the ion exchange resin device to the upstream side of the ion exchange resin device as return water, comprising: a water-to-be-treated water passing step of passing water-to-be-treated, which is raw water or a mixture of raw water and the return water, through the ion exchange resin device; a regeneration step of regenerating the ion exchange resin in the ion exchange resin device; A method for operating a water treatment system having: A method for operating a water treatment system, characterized in that the regeneration step is carried out when the load applied to the ion exchange resin by raw water contained in the water to be treated reaches a predetermined value.

[0012] [2] The method for operating a water treatment system according to [1], wherein the load imposed on the ion exchange resin by the raw water contained in the water to be treated is the difference between the cumulative flow rate of the treated water from the ion exchange resin device and the cumulative flow rate of the returned water by the return means.

[0013] [3] The return means is provided to branch off from a branching portion of a first main line that sends treated water from the ion exchange resin device to a treated water tank and send the returned water to a raw water tank upstream of the ion exchange resin device, The method for operating a water treatment system according to [1], wherein the load applied to the ion exchange resin by the raw water contained in the water to be treated is the cumulative flow rate of the ion-exchange treated water flowing from the branch portion into the treatment water tank.

[0014] [4] The return means is provided to branch off from a branching portion of a first main line that sends treated water from the ion exchange resin device to a treated water tank and send the returned water to a raw water tank upstream of the ion exchange resin device, a second main line is provided to supply treated water from the treated water tank to downstream equipment; The method for operating a water treatment system according to [1], wherein the load applied to the ion exchange resin by the raw water contained in the water to be treated is the integrated flow rate of the second main line.

[0015] [5] The water treatment system is configured such that a raw water tank is provided upstream of the ion exchange resin device, raw water and return water from the return means flow into the raw water tank, and the water to be treated is sent from the raw water tank to the ion exchange resin device, The ion exchange resin device is provided with a discharge pipe for discharging raw water-derived wastewater outside the system when water flow starts or when regeneration is performed, The load applied to the ion exchange resin by the raw water contained in the water to be treated is A value obtained by subtracting the integrated flow rate of discharged water discharged through the discharge piping from the integrated flow rate of raw water flowing into the raw water tank; or A value obtained by subtracting the integrated flow rate of the return water and the integrated flow rate of the discharged water discharged through the discharge pipe from the integrated flow rate of the water to be treated sent from the raw water tank to the ion exchange resin device. [1] A method for operating a water treatment system according to claim 1.

[0016] [6] The return means is provided to branch off from a branching portion of a first main line that sends treated water from the ion exchange resin device to a treated water tank and send the returned water to a raw water tank upstream of the ion exchange resin device, a second main line is provided to supply treated water from the treated water tank to downstream equipment; The post-treatment water treated in the post-treatment facility flows out into a circulation supply pipe and is circulated so as to return to the post-treatment facility through a circulation return pipe connected to the circulation supply pipe, The water treatment system is configured so that a portion of the circulating post-treatment water is sent to a use point through a water supply pipe, The downstream equipment is provided with a drainage pipe for draining wastewater outside the system, The load applied to the ion exchange resin by the raw water contained in the water to be treated is the cumulative flow rate of the circulation supply pipe minus the cumulative flow rate of the circulation return pipe plus the cumulative flow rate of the drainage pipe. [1] A method for operating a water treatment system.

[0017] [7] A method in which n ion exchange resin devices, numbered 1 to n (n is an integer of 2 or more), are installed in parallel, and a kth production / regeneration standby process (hereinafter, this kth process will be referred to as the kth step) in which ion exchange treated water is produced in the kth (k is any one of 1 to n) ion exchange resin device and regenerated and then standby is performed in the (k+1)th ion exchange resin device is performed, is carried out sequentially and cyclically from the 1st step to the nth step (however, in the nth step, the (n+1)th ion exchange resin device is the first ion exchange resin device), First through n instantaneous flow meters are provided to measure the outflow flow rate (instantaneous flow rate) of the ion-exchanged water from each of the first through n ion-exchange resin devices, and first through n integrating flow meters are provided to measure the integrated flow rate of the ion-exchanged water from each of the first through n ion-exchange resin devices, The integrated flow rate of the water to be treated to the kth ion exchange resin device in the kth step is calculated by multiplying the integrated flow rate of the kth integrating flow meter by the distribution ratio r(k) calculated by the following formula (1): A method for operating a water treatment system according to claim 1, wherein, in the kth step, when the load applied to the ion exchange resin of the kth ion exchange resin device by the raw water contained in the treated water flowing into the ion exchange resin device reaches a predetermined value, the method proceeds to the (k+1)th step (however, the (n+1)th step after the nth step is considered to be the first step).

[0018] r(k)=f(k) / f(1)+………+f(n) (1) Here, f(k) is the flow rate detected by the kth instantaneous flow meter, and f(1) to f(n) are the flow rates detected by the first to nth instantaneous flow meters.

[0019] [8] In the k-th step, the load applied to the ion exchange resin of the k-th ion exchange resin device by the raw water contained in the water to be treated is the difference between the value obtained by multiplying the cumulative flow rate of the treated water from the ion exchange resin device by r(k) and the value obtained by multiplying the cumulative flow rate of the returned water by the return means by r(k). [7] The method for operating a water treatment system according to [7].

[0020] [9] The return means is provided to branch from a branching portion of a first main line that joins treated water from each ion exchange resin device and sends the treated water to the treated water tank, and to send the returned water to a raw water tank upstream of the ion exchange resin device, A method for operating a water treatment system according to [7], wherein in the k-th step, the load applied to the ion exchange resin of the k-th ion exchange resin device by the raw water contained in the water to be treated is a value obtained by multiplying the cumulative flow rate of the ion exchange treated water flowing from the branch section into the treatment water tank by r(k).

[0021]

[10] The return means is provided to branch from a branching portion of a first main line that joins treated water from each ion exchange resin device and sends the treated water to a treated water tank, and to send the returned water to a raw water tank upstream of the ion exchange resin device, a second main line is provided to supply treated water from the treated water tank to downstream equipment; A method for operating a water treatment system according to [7], wherein in the k-th step, the load imposed on the ion exchange resin of the k-th ion exchange resin device by the raw water contained in the water to be treated is the value obtained by multiplying the cumulative flow rate of the second main line by r(k).

[0022]

[11] The water treatment system is configured such that a raw water tank is provided upstream of the ion exchange resin device, raw water and return water from the return means flow into the raw water tank, and the water to be treated is sent from the raw water tank to each ion exchange resin device, Each ion exchange resin device is provided with a discharge pipe for discharging raw water-derived wastewater out of the system when water flow starts or when regeneration is performed. In the k-th step, the load applied to the ion exchange resin of the k-th ion exchange resin device by the raw water contained in the water to be treated is a value obtained by subtracting the value obtained by multiplying the integrated flow rate of the discharged water discharged through the discharge piping of the kth ion exchange resin device by r(k) from the integrated flow rate of the raw water flowing into the raw water tank; or The value obtained by multiplying the integrated flow rate of the water to be treated sent from the raw water tank to the kth ion exchange resin device by r(k) minus the value obtained by multiplying the integrated flow rate of the return water by r(k) and the value obtained by multiplying the integrated flow rate of the discharged water discharged through the discharge piping of the kth ion exchange resin device by r(k). [7] A method for operating a water treatment system.

[0023]

[12] The return means is provided to branch from a branching portion of a first main line that joins treated water from each ion exchange resin device and sends the treated water to a treated water tank, and to send the returned water to a raw water tank upstream of the ion exchange resin device, a second main line is provided to supply treated water from the treated water tank to downstream equipment; The post-treatment water treated in the post-treatment facility flows out into a circulation supply pipe and is circulated so as to return to the post-treatment facility through a circulation return pipe connected to the circulation supply pipe, The water treatment system is configured so that a portion of the circulating post-treatment water is sent to a use point through a water supply pipe, The downstream equipment is provided with a drainage pipe for draining wastewater outside the system, A method for operating a water treatment system according to [7], wherein in the k-th step, the load applied to the ion exchange resin of the k-th ion exchange resin device by the raw water contained in the water to be treated is a value obtained by subtracting the value obtained by multiplying the integrated flow rate of the circulation return pipe by r(k) from the value obtained by multiplying the integrated flow rate of the circulation forward pipe by r(k), and adding the value obtained by multiplying the integrated flow rate of the drainage pipe by r(k).

[0024]

[13] A method for operating any of the water treatment systems [7] to

[12] , wherein n is 3 or more, one ion exchange resin device is regenerated and then put into standby, another ion exchange resin device is operated according to the demand for ion exchange treated water, and the remaining ion exchange resin devices produce ion exchange treated water.

[0025]

[14] A method for operating any of the water treatment systems [7] to

[12] , in which n is 2 or more, regeneration and subsequent standby are performed in one ion exchange resin device, and ion exchange-treated water is produced in the other ion exchange resin devices. [Effects of the Invention]

[0026] In the present invention, in a water treatment system in which treated water downstream of an ion exchange resin unit is returned to the upstream side of the ion exchange resin unit as needed, regeneration is performed taking into consideration the load that the returned treated water places on the ion exchange resin. For example, the returned water is considered to be no load, and the flow rate of only the raw water passing through, which places a load on the ion exchange resin, is integrated, and regeneration is performed based on this integrated flow rate.

[0027] In this way, the load on the ion exchange resin can be calculated more accurately, and regeneration can be performed at an appropriate frequency, thereby saving water, reducing chemical usage, and reducing power consumption. [Brief explanation of the drawings]

[0028] [Figure 1] FIG. 1 is a configuration diagram of a water treatment system. [Figure 2] FIG. 1 is a configuration diagram of a water treatment system. DETAILED DESCRIPTION OF THE INVENTION

[0029] Hereinafter, an embodiment will be described with reference to the drawings.

[0030] <Figure 1: One ion exchange resin tower> Figure 1 shows the flow of a water treatment system in which one series of ion exchange resin towers (referred to as ion exchange towers in Figure 1) is installed.

[0031] Raw water flows into raw water tank 2 through raw water piping 1. The water to be treated in raw water tank 2 is supplied to ion exchange resin tower 4 through piping 3. Ion-exchange treated water that has undergone ion exchange treatment in ion exchange resin tower 4 can flow into treated water tank 8 through piping 5, three-way valve 6, and piping 7 (first main line).

[0032] The ion-exchanged water can be returned from the three-way valve 6 to the raw water tank 2 through a return pipe 10 .

[0033] The three-way valve 6 is controlled by a water level control device 9 provided in the treated water tank 8. That is, when the water level in the treated water tank 8 drops to a specified lower limit, the three-way valve 6 connects the pipes 5 and 7 to allow the ion-exchanged water to flow from the ion-exchange resin tower 4 into the treated water tank 8 through the pipes 5 and 7. When the water level in the treated water tank 8 rises to a specified upper limit, the three-way valve 6 switches to connect the pipes 5 and 10 to allow the ion-exchanged water to be sent from the ion-exchange resin tower 4 to the raw water tank 2 through the pipe 10.

[0034] The ion-exchange resin tower 4 is connected to a discharge pipe 11 for discharging raw water-derived wastewater when water flow starts or when regeneration is performed.

[0035] The ion-exchanged water in the treated water tank 8 is sent to downstream equipment 13 via piping 12 (second main line) for further treatment. The downstream equipment 13 is, for example, a subsystem in a pure water production system. The downstream equipment 13 is constantly operating, and the downstream equipment treated water is constantly circulating through a circulation supply pipe 14 and a circulation return pipe 15. A portion of the downstream equipment treated water is sent to a use point 17 through a pipe 16 branching from the junction of the pipes 14 and 15, and used.

[0036] Brine is discharged from the UF membrane or the like provided in the downstream equipment 13 through the discharge pipe 18 to the outside of the system as downstream equipment wastewater.

[0037] In this embodiment, an integrating flow meter is provided at one or more of locations A to K shown in Fig. 1. Note that hereinafter, the integrating flow meters provided at locations A to K will be referred to as integrating flow meter A to integrating flow meter K, and the integrated flow rates of integrating flow meter A to integrating flow meter K will be referred to as integrated flow rates A to K. The integrating flow meters A to K are installed in pipes 1, 3, 5, 7, 10, 11, 12, 14, 15, 16, and 18, respectively.

[0038] In the conventional example, the ion exchange resin tower 4 was regenerated when the integrated flow rate C of the integrated flow meter C reached the set amount Q, but in this case, the regeneration frequency was excessive as mentioned above.

[0039] In contrast to this, in this embodiment, the actual load on the ion exchange resin tower 4 is calculated as in the following first to seventh examples, and the ion exchange resin tower 4 is regenerated based on the calculated load. Note that the first to sixth examples are based on the flow rate conditions on the wastewater side of the ion exchange resin tower 4, and the sixth and seventh examples are based on the conditions on the feedwater side of the ion exchange resin tower 4.

[0040] [Example 1] Regeneration is performed when the difference CE between the integrated flow rates C and E reaches the set water volume Q. [Example 2] When the cumulative flow rate D reaches the set water volume Q, regeneration is performed. [Example 3] Regeneration is performed when the cumulative flow rate G reaches the set water volume Q. [Example 4] Regeneration is performed when the sum of the integrated flow rates J and K (J+K) reaches the set water volume Q. [Example 5] Regeneration is performed when the sum (HI) of the difference (HI) between the integrated flow rates H and I and the integrated flow rate K reaches the set water volume Q. [Example 6] Regeneration is performed when the difference (AF) between the integrated flow rates A and F reaches the set water volume Q. [Example 7] Regeneration is performed when the result (BEF) obtained by subtracting the integrated flow rate E and the integrated flow rate F from the integrated flow rate B reaches the set water volume Q.

[0041] In the above first to seventh examples, the ion-exchange resin towers 4 are regenerated based on the substantial load of the ion-exchange resin towers 4, and excessively frequent regeneration of the ion-exchange resin towers 4 is prevented.

[0042] <Figure 2: Multiple ion exchange resin towers> Figure 2 shows the flow of a water treatment system in which three ion-exchange resin towers are installed. In Figure 2, pipe 3 branches into branch pipes 31, 32, and 33, and the water to be treated is supplied from each of branch pipes 31, 32, and 33 to ion-exchange resin towers 41, 42, and 43. Valves 31v, 32v, and 33v are installed in each of branch pipes 31, 32, and 33.

[0043] The ion-exchanged water from each of the ion-exchange resin towers 41, 42, and 43 flows from pipes 51, 52, and 53 through pipe (junction pipe) 5 to a three-way valve 6. Instantaneous flow meters f1, f2, and f3 are provided on each of the pipes 51, 52, and 53, respectively. Hereinafter, the instantaneous flow rates detected by the instantaneous flow meters f1, f2, and f3 will be referred to as instantaneous flow rates f1, f2, and f3.

[0044] When water starts flowing through each of the ion exchange resin towers 41, 42, 43 or when regeneration is performed, raw water-derived wastewater is discharged from each of the discharge pipes 61, 62, 63 through a pipe (junction pipe) 11. The integrating flow meter F of the pipe 11 is omitted, and instead, integrating flow meters F1, F2, F3 are provided in each of the pipes 61, 62, 63. The integrated flow rates of the integrating flow meters F1, F2, F3 will be referred to as integrated flow rates F1, F2, F3 hereinafter.

[0045] 1 is omitted, and instead, integrating flow meters C1, C2, and C3 are provided in each of the pipes 51, 52, and 53. The integrated flow rates of the integrating flow meters C1, C2, and C3 will hereinafter be referred to as integrated flow rates C1, C2, and C3.

[0046] The other configurations in FIG. 2 are the same as those in FIG. 1, and the same reference numerals denote the same parts.

[0047] Each ion exchange resin tower 41, 42, and 43 has the same type of ion exchange resin and the same filling amount, and they are operated in a merry-go-round fashion. For example, in the first step, the ion exchange resin tower 41 is in main operation (continuously producing ion-exchanged water), the ion exchange resin tower 42 is operated when needed (when the amount of water produced by the ion exchange resin tower 41 does not meet the demand for ion-exchanged water), and the ion exchange resin tower 43 is regenerated and then placed on standby (hereinafter sometimes referred to as regeneration and standby). In the second step, the ion exchange resin tower 42 is in main operation, the ion exchange resin tower 43 is operated when needed, and the ion exchange resin tower 41 is regenerated and placed on standby. In the third step, the ion exchange resin tower 43 is in main operation, the ion exchange resin tower 41 is operated when needed, and the ion exchange resin tower 42 is regenerated and placed on standby. The first, second, and third steps are then rotated in sequence. Therefore, the cumulative flow rate of treated water through the ion exchange resin towers 41, 42, and 43 changes with each step.

[0048] In the first step, the integrated flow rate of the ion-exchange resin tower 41 is C1.

[0049] In the first step, the proportion r1 of ion exchange treated water originating from the ion exchange resin tower 41 among the returned ion exchange treated water flowing through the return pipe 10 is calculated as r1 = (f1) / (f1 + f2 + f3) using the detected flow rates f1, f2, f3 of each instantaneous flow rate f1, f2, f3.

[0050] Using this ratio r1, the amount of treated water that has passed through the ion exchange resin tower 41 among the cumulative flow rates B, D, E, G to K of each cumulative flow meter B, D, E, G to K in the first step is expressed as B·r1, D·r1, E·r1, G·r1, H·r1, I·r1, J·r1, and K·r1, respectively.

[0051] In the second step, the amount of treated water that has passed through the main operating ion exchange resin tower 42 among the integrated flow rates B, D, E, G to K of the respective integrating flow meters B, D, E, G to K is expressed as the value obtained by multiplying each of B, D, E, G to K by r2. Note that r2 is expressed as r2=f2 / (f1+f2+f3) using the instantaneous flow rates f1 to f3 in the second step.

[0052] In the third step, the amount of treated water that has passed through the main operating ion exchange resin tower 43 among the integrated flow rates B, D, E, G to K of each integrating flow meter B, D, E, G to K is expressed as the value obtained by multiplying each of B, D, E, G to K by r3. However, r3 is expressed as r3=f3 / (f1+f2+f3) using the instantaneous flow rates f1 to f3 in the second step.

[0053] When the time for regeneration of the ion exchange resin tower 41 arrives in the first to seventh examples below while the first step is being performed, the first step is completed and the process moves to the second step. In the second step, as described above, the ion exchange resin tower 42 is in main operation, the ion exchange resin tower 43 is operated as needed, and the ion exchange resin tower 41 is regenerated and on standby.

[0054] [First example] Accumulated flow rate C1 ·r1 and the difference C1 between the integrated flow rate E·r1 ·r1 When -E·r1 reaches the set water volume Q, the process moves to the second step. [Second example] When the integrated flow rate D·r1 reaches the set water volume Q, the process moves to the second step. [Third example] When the integrated flow rate G·r1 reaches the set water volume Q, the process moves to the second step. [Fourth example] When the sum of the integrated flow rate J·r1 and the integrated flow rate K·r1 (J·r1+K·r1) reaches the set water volume Q, the process moves to the second step. [Fifth example] The process moves to the second step when the sum of the difference between the integrated flow rate H·r1 and the integrated flow rate I·r1 (H·r1-I·r1) and the integrated flow rate K·r1 (H·r1-I·r1)+K·r1 reaches the set water volume Q. [Sixth example] Accumulated flow rate A and accumulated flow rate F1 ·r1 Difference between (A-F1 ·r1 ) reaches the set water volume Q, the process moves to the second step. [Seventh example] Accumulated flow rate B·r1 to accumulated flow rate E·r1 and accumulated flow rate F 1·r1 B·r1-E·r1-F1 subtracted ·r1 When the set water volume Q is reached, the process moves to the second step.

[0055] The timing of transition from the second step to the third step to regenerate the ion-exchange resin tower 42 corresponds to the case where r1 is changed to r2, C1 is changed to C2, and F1 is changed to F2 in the first to seventh examples.

[0056] The timing of transition from the third step to the first step to regenerate the ion exchange resin tower is the same as when r1 is changed to r3, C1 to C3, and F1 to F3 in the first to seventh examples.

[0057] In this way, in the case of FIG. 2 as well, the ion exchange resin towers 41, 42, and 43 are regenerated based on their substantial loads, thereby preventing excessively frequent regeneration of the ion exchange resin towers.

[0058] The above embodiment is one example of the present invention, and the present invention may be embodied in other forms. For example, two or four or more ion exchange resin towers may be installed. In a system with four or more ion exchange resin towers, two or more ion exchange resin towers may be operated to produce deionized water, one ion exchange resin tower may be regenerated or on standby, and one ion exchange resin tower may be operated according to the demand for deionized water. The ion exchange resin tower operated according to the demand for deionized water may be omitted, one ion exchange resin tower may be regenerated or on standby, and the other ion exchange resin towers may be operated to produce deionized water.

[0059] In the present invention, the method for regenerating the ion exchange resin is not particularly limited, and for example, a conventional method using an alkali or an acid can be employed. [Explanation of symbols]

[0060] 2 Raw Water Tank 4,41,42,43 Ion exchange resin tower 8 Treatment tank 13 Post-processing equipment 17 Use Points

Claims

1. A method for operating a water treatment system having an ion exchange resin device containing ion exchange resin and a return means for returning at least a portion of ion-exchange-treated water from the ion exchange resin device to an upstream side of the ion exchange resin device as return water, comprising: a water-to-be-treated water passing step of passing water-to-be-treated, which is raw water or a mixture of raw water and the return water, through the ion exchange resin device; a regeneration step of regenerating the ion exchange resin in the ion exchange resin device; A method for operating a water treatment system having: A method for operating a water treatment system, characterized in that the regeneration step is performed when a load applied to the ion exchange resin by raw water contained in the water to be treated reaches a predetermined value, A method for operating a water treatment system in which the load applied to the ion exchange resin by the raw water contained in the water to be treated is the difference between the cumulative flow rate of treated water from the ion exchange resin device and the cumulative flow rate of returned water by the return means.

2. A method for operating a water treatment system having an ion exchange resin device containing ion exchange resin and a return means for returning at least a portion of ion-exchange-treated water from the ion exchange resin device to an upstream side of the ion exchange resin device as return water, comprising: a water-to-be-treated water passing step of passing water-to-be-treated, which is raw water or a mixture of raw water and the return water, through the ion exchange resin device; a regeneration step of regenerating the ion exchange resin in the ion exchange resin device; A method for operating a water treatment system having: A method for operating a water treatment system, characterized in that the regeneration step is performed when a load applied to the ion exchange resin by raw water contained in the water to be treated reaches a predetermined value, The return means is provided to branch off from a branching portion of a first main line that sends treated water from the ion exchange resin device to a treated water tank, and to send the returned water to a raw water tank upstream of the ion exchange resin device, A method for operating a water treatment system, wherein the load applied to the ion exchange resin by raw water contained in the water to be treated is the cumulative flow rate of ion-exchanged water flowing from the branch portion into the treatment water tank.

3. A method for operating a water treatment system having an ion exchange resin device containing ion exchange resin and a return means for returning at least a portion of ion-exchange-treated water from the ion exchange resin device to an upstream side of the ion exchange resin device as return water, comprising: a water-to-be-treated water passing step of passing water-to-be-treated, which is raw water or a mixture of raw water and the return water, through the ion exchange resin device; a regeneration step of regenerating the ion exchange resin in the ion exchange resin device; A method for operating a water treatment system having: A method for operating a water treatment system, characterized in that the regeneration step is performed when a load applied to the ion exchange resin by raw water contained in the water to be treated reaches a predetermined value, The return means is provided to branch off from a branching portion of a first main line that sends treated water from the ion exchange resin device to a treated water tank, and to send the returned water to a raw water tank upstream of the ion exchange resin device, a second main line is provided to supply treated water from the treated water tank to downstream equipment; A method for operating a water treatment system, wherein the load applied to the ion exchange resin by raw water contained in the water to be treated is the integrated flow rate of the second main line.

4. A method for operating a water treatment system having an ion exchange resin device containing ion exchange resin and a return means for returning at least a portion of ion-exchange-treated water from the ion exchange resin device to an upstream side of the ion exchange resin device as return water, comprising: a water-to-be-treated water passing step of passing water-to-be-treated, which is raw water or a mixture of raw water and the return water, through the ion exchange resin device; a regeneration step of regenerating the ion exchange resin in the ion exchange resin device; A method for operating a water treatment system having: A method for operating a water treatment system, characterized in that the regeneration step is performed when a load applied to the ion exchange resin by raw water contained in the water to be treated reaches a predetermined value, The water treatment system is configured such that a raw water tank is provided upstream of the ion exchange resin device, raw water and return water from the return means flow into the raw water tank, and the water to be treated is sent from the raw water tank to the ion exchange resin device, The ion exchange resin device is provided with a discharge pipe for discharging raw water-derived wastewater outside the system when water flow starts or when regeneration is performed, The load applied to the ion exchange resin by the raw water contained in the water to be treated is A value obtained by subtracting the integrated flow rate of discharged water discharged through the discharge piping from the integrated flow rate of raw water flowing into the raw water tank; or A value obtained by subtracting the integrated flow rate of the return water and the integrated flow rate of the discharged water discharged through the discharge pipe from the integrated flow rate of the water to be treated sent from the raw water tank to the ion exchange resin device. A method for operating a water treatment system.

5. A method for operating a water treatment system having an ion exchange resin device containing ion exchange resin and a return means for returning at least a portion of ion-exchange-treated water from the ion exchange resin device to an upstream side of the ion exchange resin device as return water, comprising: a water-to-be-treated water passing step of passing water-to-be-treated, which is raw water or a mixture of raw water and the return water, through the ion exchange resin device; a regeneration step of regenerating the ion exchange resin in the ion exchange resin device; A method for operating a water treatment system having: A method for operating a water treatment system, characterized in that the regeneration step is performed when a load applied to the ion exchange resin by raw water contained in the water to be treated reaches a predetermined value, The return means is provided to branch off from a branching portion of a first main line that sends treated water from the ion exchange resin device to a treated water tank, and to send the returned water to a raw water tank upstream of the ion exchange resin device, a second main line is provided to supply treated water from the treated water tank to downstream equipment; The post-treatment water treated in the post-treatment facility flows out into a circulation supply pipe and is circulated so as to return to the post-treatment facility through a circulation return pipe connected to the circulation supply pipe, The water treatment system is configured so that a portion of the circulating post-treatment water is sent to a use point through a water supply pipe, The downstream equipment is provided with a drainage pipe for draining wastewater outside the system, A method for operating a water treatment system in which the load applied to the ion exchange resin by the raw water contained in the water to be treated is the cumulative flow rate of the circulation supply pipe minus the cumulative flow rate of the circulation return pipe plus the cumulative flow rate of the drainage pipe.

6. A method for operating a water treatment system having an ion exchange resin device containing ion exchange resin and a return means for returning at least a portion of ion-exchange-treated water from the ion exchange resin device to an upstream side of the ion exchange resin device as return water, comprising: a water-to-be-treated water passing step of passing water-to-be-treated, which is raw water or a mixture of raw water and the return water, through the ion exchange resin device; a regeneration step of regenerating the ion exchange resin in the ion exchange resin device; A method for operating a water treatment system having: A method for operating a water treatment system, characterized in that the regeneration step is performed when a load applied to the ion exchange resin by raw water contained in the water to be treated reaches a predetermined value, A method in which n ion exchange resin devices, numbered 1 to n (n is an integer of 2 or more), are installed in parallel, and a kth production / regeneration standby process (hereinafter, this kth process will be referred to as the kth step) in which ion exchange treated water is produced in the kth (k is any of 1 to n) ion exchange resin device and regenerated and then standby is performed in the (k+1)th ion exchange resin device is performed, is performed sequentially and cyclically from the 1st step to the nth step (however, in the nth step, the (n+1)th ion exchange resin device is the first ion exchange resin device), first through n-th instantaneous flow meters for measuring the outflow flow rate (instantaneous flow rate) of ion-exchanged water from each of the first through n-th ion-exchange resin devices, and first through n-th integrating flow meters for measuring the integrated flow rate of ion-exchanged water from each of the ion-exchange resin devices, are provided; The integrated flow rate of the water to be treated to the kth ion exchange resin device in the kth step is calculated by multiplying the integrated flow rate of the kth integrating flow meter by the proportional distribution ratio r(k) calculated by the following formula (1): A method for operating a water treatment system, in which, when the load applied to the ion exchange resin of the kth ion exchange resin device by the raw water contained in the treated water flowing into the ion exchange resin device reaches a predetermined value in the kth step, the system proceeds to the (k+1)th step (however, the (n+1)th step after the nth step is considered the first step). r(k)=f(k) / f(1)+……+f(n) (1) Here, f(k) is the flow rate detected by the kth instantaneous flow meter, and f(1) to f(n) are the flow rates detected by the first to nth instantaneous flow meters.

7. 7. A method for operating a water treatment system according to claim 6, wherein in the kth step, the load applied to the ion exchange resin of the kth ion exchange resin device by the raw water contained in the treated water is the difference between the value obtained by multiplying the cumulative flow rate of the treated water from the ion exchange resin device by r(k) and the value obtained by multiplying the cumulative flow rate of the returned water by the return means by r(k).

8. The return water supply means is provided to branch off from a branching portion of a first main line that joins treated water from each ion exchange resin device and sends the treated water to a treated water tank, and to send the returned water to a raw water tank upstream of the ion exchange resin device, 7. A method for operating a water treatment system according to claim 6, wherein in the kth step, the load applied to the ion exchange resin of the kth ion exchange resin device by the raw water contained in the water to be treated is a value obtained by multiplying the cumulative flow rate of the ion exchange treated water flowing from the branch section into the treatment water tank by r(k).

9. The return water supply means is provided to branch off from a branching portion of a first main line that joins treated water from each ion exchange resin device and sends the treated water to a treated water tank, and to send the returned water to a raw water tank upstream of the ion exchange resin device, a second main line is provided to supply treated water from the treated water tank to downstream equipment; 7. A method for operating a water treatment system according to claim 6, wherein in the kth step, the load applied to the ion exchange resin of the kth ion exchange resin device by the raw water contained in the treated water is a value obtained by multiplying the integrated flow rate of the second main line by r(k).

10. The water treatment system is configured such that a raw water tank is provided upstream of the ion exchange resin device, raw water and return water from the return means flow into the raw water tank, and the water to be treated is sent from the raw water tank to each ion exchange resin device, Each ion exchange resin device is provided with a discharge pipe for discharging raw water-derived wastewater out of the system when water flow starts or when regeneration is performed. In the k-th step, the load applied to the ion exchange resin of the k-th ion exchange resin device by the raw water contained in the water to be treated is a value obtained by subtracting a value obtained by multiplying the integrated flow rate of the discharged water discharged through the discharge pipe of the kth ion exchange resin device by r(k) from the integrated flow rate of the raw water flowing into the raw water tank; or A value obtained by multiplying the integrated flow rate of the return water by r(k) and the integrated flow rate of the discharged water discharged through the discharge pipe of the kth ion exchange resin device by r(k) from the value obtained by multiplying the integrated flow rate of the water to be treated delivered from the raw water tank to the kth ion exchange resin device by r(k).

7. The method for operating a water treatment system according to claim 6, wherein

11. The return water supply means is provided to branch off from a branching portion of a first main line that joins treated water from each ion exchange resin device and sends the treated water to a treated water tank, and to send the returned water to a raw water tank upstream of the ion exchange resin device, a second main line is provided to supply treated water from the treated water tank to downstream equipment; The post-treatment water treated in the post-treatment facility flows out into a circulation supply pipe and is circulated so as to return to the post-treatment facility through a circulation return pipe connected to the circulation supply pipe, The water treatment system is configured so that a portion of the circulating post-treatment water is sent to a use point through a water supply pipe, The downstream equipment is provided with a drainage pipe for draining wastewater outside the system, 7. A method for operating a water treatment system according to claim 6, wherein in the kth step, the load applied to the ion exchange resin of the kth ion exchange resin device by the raw water contained in the treated water is a value obtained by subtracting the value obtained by multiplying the integrated flow rate of the circulation return pipe by r(k) from the value obtained by multiplying the integrated flow rate of the circulation supply pipe by r(k), and adding the value obtained by multiplying the integrated flow rate of the drainage pipe by r(k).

12. A method for operating a water treatment system according to any one of claims 6 to 11, wherein n is 3 or more, one ion exchange resin device is regenerated and then put into standby, another ion exchange resin device is operated according to the demand for ion exchange treated water, and the remaining ion exchange resin devices produce ion exchange treated water.

13. 12. The method for operating a water treatment system according to claim 6, wherein n is 2 or more, and one ion exchange resin device is used for regeneration and subsequent standby, and the other ion exchange resin device produces ion-exchanged water.

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