Control table creation method, control table creation program, and water quality control method

Abstract

Provided are a water quality control method capable of performing control for maintaining water quality management items at appropriate values at low cost, a method for creating a control table used therefor, and a control table creation program. 【Solution means】This method for creating a control table and the control table creation program create a control table using actually measured data in an operating management system. Further, for the insufficient part, it is calculated by an operation based on the actually measured data. Therefore, the control table can be created without using expensive equipment. Further, the acquisition of data necessary for creating the control table can be handled by existing equipment, and the introduction cost can be kept low. Further, in this water quality control method, a large calculation load does not occur in the management value setting device. Therefore, it is possible to use existing equipment for the management value setting device, and the introduction cost of the present invention can be kept low.

Description

Technical Field

[0001] The present invention relates to a technique for controlling the chemical dosage so that a predetermined water quality management item reaches a preset value at a downstream target point, and particularly to a control table for setting the value of the water quality management item on the upstream side Operation It relates to a forming method, a control table creation program, and a water quality control method using this control table.

Background Art

[0002] For example, the water supply in Japan is an important social infrastructure that is indispensable for social life and economic activities that can stably supply safe water that can be directly consumed through the water distribution network. Here, in the Enforcement Regulations of the Waterworks Act, regarding chlorine disinfection, it is stipulated that the free residual chlorine concentration of water at the water supply faucet (hereinafter referred to as the residual chlorine concentration) should be ensured to be 0.1 mg / L or more. However, with the decline in the population in Japan, the residence time of the water distribution network has a tendency to increase. Along with this, the residual chlorine concentration in the water supply process (management system) of the water distribution network decreases, and there is concern about the decline in the bactericidal effect during water distribution. In response to this, it is conceivable to increase the dosage of the bactericide (generally sodium hypochlorite) at the water purification facility or the like, which is the water supply source, and set the chlorine concentration at the time of supply to be high in advance.

[0003] However, in the report of the "Study Group on Delicious Water" in the Ministry of Health, Labour and Welfare in 1985, a guideline was shown that the residual chlorine concentration should be 0.4 mg / L or less as a requirement for delicious water. Also, in the comfortable water quality items that supplement the water quality standards implemented in December 1993, a value of about 1 mg / L or less is shown as the management set value for the residual chlorine concentration. Thus, regarding tap water, it is required to appropriately manage the residual chlorine concentration based on the lower limit value as a hygienic measure and the upper limit value as a comfortable water quality item, and there is a limit to managing the residual chlorine concentration of the entire water distribution network only by chlorine input at the water supply source.

[0004] As a countermeasure against this, for example, as shown in the schematic diagram of FIG. 1, a chemical injection facility is provided in a water distribution facility such as a service reservoir in the middle of the management system, and "top-up chlorine" in which a bactericide is additionally injected at the chemical injection point P is known. Although the multi-point injection method is generally used for this top-up chlorine, in recent years when the number of waterworks employees is decreasing, the multi-point injection method has problems such as a large human burden and the need for a large number of chemical injection facilities for top-up chlorine, resulting in a large burden on equipment costs. For this reason, it is required to perform efficient top-up chlorine by minimizing the chemical injection point P for top-up chlorine as much as possible. However, in the management system, the flow rate and residence time vary depending on the pipe diameter, gradient, and water demand, and a mere intermediate point on the map (considering only the pipe length) cannot be said to be a preferable chemical injection point P. Regarding this problem, the inventors of the present application have made the invention described in the following [Patent Document 1] regarding a chemical injection point selection method for selecting a chemical injection point P capable of efficiently performing top-up chlorine.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] According to the invention described in this [Patent Document 1], it has become possible to select an effective chemical injection point P in the middle of the management system, and it has become possible to perform efficient top-up chlorine throughout the management system. By the way, for example, the rate of decrease of chlorine-based bactericides added to tap water varies depending on the water temperature. In summer when the water temperature is high, the decrease is rapid and the residual chlorine concentration becomes low, while in winter when the water temperature is low, the decrease is slow and the residual chlorine concentration tends to be high. For this reason, in order to maintain the residual chlorine concentration in the management system at an appropriate value, it is necessary to change the chemical injection amount at the chemical injection point P according to the water temperature. Conventionally, the adjustment of the chemical injection amount corresponding to such a water temperature change has been carried out by the administrator based on experience. However, due to a shortage of manpower, efficiency improvement of operations, reduction of work burden, etc., it has been required to perform these controls automatically.

[0007] And as the most common control method in such a mechanism, there is feedback control that adjusts the chemical dosage according to the measured value of the water quality management item (residual salt concentration) at the target point E. However, in the water distribution pipe network, the time (delay time) for water to reach from the chemical injection point P to the target point E is long, and in some cases, it may take more than two days. In such feedback control in a path with a long delay time, overshoot and undershoot are large, and it is difficult for the chemical dosage to repeatedly maintain an appropriate residual salt concentration without excess or deficiency.

[0008] Also, a method of obtaining measurement data, deriving a regression equation, and calculating the chemical dosage using this regression equation can be considered. However, in an actually operating water distribution pipe network, experimental dosages (excessive or insufficient) of chemicals cannot be applied. For this reason, the obtained measurement data is concentrated around the appropriate value, making it difficult to accurately derive a regression equation and having the problem of poor accuracy.

[0009] Furthermore, although learning and control by AI (artificial intelligence), which has been rapidly developing in recent years, are considered effective methods for such a control system, there is a problem that the production cost of AI devices and AI programs is high, making it difficult to introduce them from a cost perspective.

[0010] The present invention has been made in view of the above circumstances, and an object thereof is to provide a water quality control method capable of maintaining the water quality management item at an appropriate value with low cost using existing equipment as much as possible. Also, a control table capable of creating a control table used in this water quality control method with low cost using existing equipment as much as possible Operation A forming method and a control table creation program are provided.

Means for Solving the Problems

[0011] The present invention is (1) A control table creation method for creating a control table for controlling the chemical dosage at the chemical injection point P in the management system, The existing facilities installed in the management system monitor the water quality management items at the chemical input point P and the target point E downstream, and based on the changes in the water quality management items, from the chemical agent input point P Eyes Step S102 of setting the arrival time to the reference point E as the delay time τ The existing facilities installed in the management system Step S104 of acquiring the water quality information of the management system for a predetermined period Step S106 of acquiring the value of the water quality management item at the chemical agent input point P as the front-end value Cu for a predetermined period The value of the water quality management item at the target point E is the back-end value C L Step S10 of acquiring it for a predetermined period 8 and Perform The computer on which the control table creation program is launched Step S207 of calculating the average water quality value T of the water quality information for a predetermined data period each front-end value Cu, the back-end value C after the elapse of the delay time τ from the measurement time of the front-end value Cu Lτ and the front-end value Cu or the back-end value C Lτ and the average water quality value T related thereto are grouped into group data in Step S208 Step S220 of creating a data table having the water quality value bands at equal intervals corresponding to the average water quality value T and the front-end value bands at equal intervals corresponding to the front-end value Cu in rows and columns, and setting the central value Cn of each front-end value band For the data table, the back-end value C Lτ is stored in the cell where the water quality value band to which the average water quality value T of the group data belongs and the front-end value band to which the front-end value Cu belongs intersect in Step S222 When there are blank cells in the data table, the decrease rate coefficient k of all the back-end values C Lτ in the water quality value band where the blank cells exist is calculated based on the following formula A using the central value Cn of the front-end value band to which each back-end value C Lτ belongs in Step S302 k=(1 / τ)log e (Cn / C Lτ )···(A) Step S304 of calculating the average value k ave of the decrease rate coefficient k for each water quality value band The back-end value C of the blank cell LτA backend value calculation step S306 that calculates using the central value Cn' of the front-end value range to which the blank cell belongs according to the following formula B, C Lτ =Cn’·exp(-k ave ·τ)···(B) When a plurality of backend values C Lτ are stored in one cell, a step S332 of setting the average value of the stored backend values C Lτ as the backend value C Lτ of that cell, A basic table setting step S340 that uses the data table as a basic data table, Perform By providing a control table creation method characterized by the above, the above problems are solved. (2) The management target value Ca of the water quality management item at the target point E Set for the computer Step S203, The computer After the basic table setting step S340, When the backend value C Lτ of the maximum front-end value range of the basic data table is less than the lower limit of the predetermined numerical range of the management target value Ca, a step S346a of expanding the upper limit front-end value range of the data table in the direction of increasing numerical value to provide an expanded front-end value range, When the backend value C Lτ of the minimum front-end value range of the basic data table exceeds the upper limit of the predetermined numerical range of the management target value Ca, a step S346b of expanding the lower limit front-end value range of the data table in the direction of decreasing numerical value to provide an expanded front-end value range, A step S348 of calculating the backend value C Lτ of the cells in the expanded front-end value range based on the backend value calculation step, Perform By providing the control table creation method described in the above (1) characterized by the above, the above problems are solved. (3) A control table creation program for creating a control table for controlling the chemical dosage at the chemical injection point P of the management system, The data of the water quality information of the management system acquired in advance over a predetermined period, the data of the front-end value Cu as the value of the water quality management item at the chemical injection point P, and the back-end value C as the value of the water quality management item at the target point E L A process of reading the data (step S204), A process of obtaining a data period for calculating the average water quality value T which is the average value of the water quality information (step S206), A process of calculating the average water quality value T of the water quality information using the data period (step S207), Each front-end value Cu, the back-end value C after the elapse of a preset delay time τ from the measurement time of the front-end value Cu Lτ And the front-end value Cu or the back-end value C Lτ And the average water quality value T related thereto, and a process of grouping them into group data (step S208), Create a data table having the equally spaced water quality value bands corresponding to the average water quality value T and the equally spaced front-end value bands corresponding to the front-end value Cu in rows and columns, and a process of setting the central value Cn of each front-end value band (step S220), For the data table, the back-end value C Lτ Is stored in the cell where the water quality value band to which the average water quality value T of the group data belongs and the front-end value band to which the front-end value Cu belongs intersect (step S222), When there are blank cells in the data table, the decrease rate coefficient k of all the back-end values C Lτ In the water quality value band where the blank cells exist is calculated based on the following formula A using the central value Cn of the front-end value band to which each back-end value C Lτ Belongs (step S302), k=(1 / τ)log e (Cn / C Lτ )···(A) A process of calculating the average value k ave Of the decrease rate coefficient k for each water quality value band (step S304), A back-end value calculation process of calculating the back-end value C Lτ Of the blank cell using the central value Cn’ of the front-end value band to which the blank cell belongs according to the following formula B (step S306), C Lτ=Cn’·exp(-k ave ·τ)···(B) When a plurality of backend values C are stored in one cell Lτ in the case where, the average value of the stored backend values C Lτ is set as the backend value C of that cell Lτ processing (step S332), and providing a control table creation program that causes a computer to execute basic table setting processing (step S340) using the data table as a basic data table, thereby solving the above problems. (4) Processing for setting a management target value Ca of a water quality management item at the target point E (step S203), After the basic table setting processing (step S340), If the backend value C of the maximum front-end value band of the basic data table Lτ is less than the lower limit of a predetermined numerical range of the management target value Ca, processing for expanding the upper front-end value band of the data table in the direction of increasing numerical values to provide an expanded front-end value band (step S346a), If the backend value C of the minimum front-end value band of the basic data table Lτ exceeds the upper limit of a predetermined numerical range of the management target value Ca, processing for expanding the lower front-end value band of the data table in the direction of decreasing numerical values to provide an expanded front-end value band (step S346b), Calculating the backend value C of the cells in the expanded front-end value band Lτ processing based on the backend value calculation process (step S348), and providing the control table creation program according to (3) above, which causes a computer to execute, thereby solving the above problems. (5) A water quality control method for controlling the value of a water quality management item at the target point E using the control table created by the control table creation method according to (1) or (2) above, a setting step of determining a set value of a water quality management item at the chemical injection point P, a control step of controlling the injection amount of the chemical so that the value of the water quality management item at the chemical injection point P becomes the set value, and having the setting step is Step S390 of setting the management target value of the water quality management item at the target location E Among the control tables, the trailing end value C of the value closest to the management target value Lτ The cell storing the value is extracted for each water quality value band, and the center value Cn of the leading end value band of the cell is set as the set value for each water quality value band to create a set value table in step S392 Step S401 of obtaining the value of the water quality information of the management system and calculating the average water quality value T' at the time of control Step S402 of referring to the set value table, selecting the set value corresponding to the water quality value band to which the average water quality value T' belongs, and setting it as the set value of the control step By providing a water quality control method characterized by having the above, the above problems are solved (6) A management value setting device 50 that performs a setting step is provided The management value setting device 50 includes a recording unit 52 in which at least a control table is recorded, and a control unit 54 that creates a set value table and determines the set value of the control step based on the average water quality value T'. By providing the water quality control method described in the above (5), the above problems are solved (7) A water quality control unit 30 that performs a control step is provided The water quality control unit 30 includes a management value measurement unit 32 that acquires the value of the management item at the chemical injection point P, a chemical injection unit 34 that injects chemicals at the chemical injection point P, and a control unit 36 that controls the operation of the chemical injection unit 34 so that the value of the water quality management item acquired from the management value measurement unit 32 becomes the set value determined by the management value setting device 50. By providing the water quality control method described in the above (6), the above problems are solved

Effect of the Invention

[0012] The control table according to the present invention OperationThe control table creation method and the control table creation program create a control table using the measured data in the management system that is actually in operation. Also, for the insufficient parts, they are calculated by operations based on the measured data. Therefore, it is possible to create a control table without using expensive devices such as AI devices. Also, the acquisition of data required for creating the control table can be handled by existing facilities, and the introduction cost can be kept low. Further, the water quality control method according to the present invention operates by having the management value setting device record the created control table, and no large calculation load is generated on the management value setting device. Therefore, it is possible to use existing devices for the management value setting device, and the introduction cost of the present invention can be kept low.

Brief Description of the Drawings

[0013]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Embodiments for Carrying Out the Invention

[0014] The control table according to the present invention OperationA water quality forming method, a control table creation program, and a water quality control method will be described with reference to the drawings. Here, the water distribution pipe network of a water supply system is used as the management system, a chemical injection point P is provided in the middle of the network, and the end equipment of the management system is used as the target point E for the description. Also, the water quality information is described as the water temperature of the water flowing through the management system, and the water quality management item is described as the residual salt concentration. However, the invention of the present application is not limited to this. Examples of the management system include water purification facilities, wastewater treatment facilities, etc. Examples of the water quality information include residual salt concentration, turbidity, pH, flow rate, etc. Also, examples of the water quality management items include turbidity, pH, etc. in addition to the residual salt concentration. Further, as a more specific example, a water purification facility is used as the management system, the water quality information is the turbidity of the raw water, and the water quality management item is the turbidity of the purified water, and the control of the coagulant injection amount or the coagulant injection rate is mentioned. Also, a water purification facility is used as the management system, the water quality information is the residual salt concentration in the middle, and the water quality management item is the residual salt concentration after the vicinity of the water outlet point, and the control of the injection amount or the injection rate of an additional chlorine-based disinfectant is mentioned. Furthermore, the water quality information is not limited to one and may be plural. In this case, the control table is three-dimensional and solid.

[0015] Here, FIG. 1 is a schematic diagram showing an example of a water supply system as a management system to which the present invention is applied. It should be noted that a plurality of water distribution pipe networks (not shown) are connected to this management system, and tap water is distributed to each household through this water distribution pipe network. Further, the water supply source S in FIG. 1 is a water distribution facility such as a water purification facility that supplies sterilized raw water to the management system. And when the distance of the management system is long and the water quality management item (here, the residual salt concentration) falls below the appropriate value on the way, a chemical injection point P for adding chlorine is installed. It should be noted that the chemical injection point P is, for example, a water storage tank of a well-known water distribution facility such as a water distribution tank, a pressure reducing tank, or a pump station where chlorine injection is possible, and it is preferably provided in a facility at a position where the chemical can be efficiently distributed using the invention described in [Patent Document 1] or the like. And the present invention is for controlling the chemical injection amount or chemical injection rate at the chemical injection point P located upstream of this target point E so that the value of the water quality management item (residual salt concentration) at the downstream target point E becomes the management target value. It should be noted that the target point E assumes a water distribution facility (terminal facility) located at the most downstream of the management system. However, for example, when there are a plurality of chemical injection points P, a water distribution facility in the middle of the management system may be used as the target point E, and the present invention may be applied to the chemical injection point P immediately before it. Further, when there is no chemical injection point P between the water supply source S and the target point E, the present invention may be applied with the water supply source S as the chemical injection point P.

[0016] Next, regarding the control table according to the present invention Operation An explanation will be given using the process flowchart of FIG. 2(a) regarding the formation method. First, the time (delay time τ) from when the water flowing through the management system exits the previous chemical injection point P until it reaches the target point E is obtained (step S102). This delay time τ is 、 Obtained from the time until the change in the chemical injection amount (water quality management item) at the chemical injection point P is reflected in the value of the water quality management item at the target point E by monitoring the water quality management items (residual salt concentration) at the chemical injection point P and the target point E 。 It should be noted that this delay time τ is basically a fixed value. Also, the delay time τ is sufficient in time units and minutes are not necessary.

[0017] Next, the water quality information of the management system is measured and obtained for a predetermined period. There is no particular limitation on the measurement frequency of the water quality information at this time. However, when the water quality information is the water temperature, it is preferably measured at least twice or more during the daytime when the air temperature (water temperature) is high and at night when the air temperature (water temperature) is low. Basically, it is preferably measured every hour. In addition, the position where the water quality information is measured is not necessarily limited to the chemical agent injection point P and the target point E, and it can be measured at any location within the management system and any water distribution facility. Further, the information on the measurement date and time required for subsequent grouping of data is recorded in the water quality information (step S104).

[0018] Also, before and after this, the water quality management item (residual salt concentration) at the chemical agent injection point P is measured, and this is set as the front-end value Cu (step S106). Incidentally, the measurement point of the front-end value Cu is preferably near the water outlet point of the chemical agent injection point P where the chemical agent is sufficiently dissolved. Also, the water quality management item (residual salt concentration) at the target point E is measured, and this is set as the back-end value C L (step S108). Incidentally, there is no particular limitation on the measurement frequency of the front-end value Cu and the back-end value C L . However, it is particularly preferable that both are measured every hour so that there is a back-end value C Lτ after the delay time τ during the subsequent grouping. Furthermore, the information on the measurement date and time required for subsequent grouping of data is recorded in these front-end value Cu and back-end value C L .

[0019] Then, the acquisition of these water quality information, front-end value Cu, and back-end value C L is continuously performed for a predetermined period. In particular, when the water quality information is the water temperature, in order to obtain data during the high-temperature period in summer and the low-temperature period in winter, it is continuously performed for at least half a year including summer and winter, preferably for one year. Thereby, the acquisition of data necessary for deriving the control table is completed.

[0020] Next, the control table is created from the values of these water quality information, front-end value Cu, and back-end value C L as follows (step S200). Here, FIG. 3 is a flowchart of the control table creation program according to the present invention.

[0021] First, set the delay time τ obtained in step S102 by inputting it to the computer on which the control table creation program according to the present invention has been started (step S202). Next, set the management target value Ca of the water quality management item (residual salt concentration) at the target point E by inputting it to this computer (step S203). Next, cause this computer to read the data of the water quality information (water temperature), the front-end value Cu, and the rear-end value C obtained in steps S104, S106, and S108 (step S204). L

[0022] Next, the control table creation program acquires the data period for calculating the average water quality value T of the water quality information (step S206). Here, when the water quality information is the water temperature, it is preferable that the data period is a multiple of 24 hours so that the average value of the measurement data during the daytime with high air temperature and the measurement data during the nighttime with low air temperature can be obtained. Also, it is preferable that the setting of the multiple a of 24 hours is calculated by the following formula C based on the delay time τ. a = [0.5 × (1 + (τ / 12))] ··· (C) Here, [ ] means the Gaussian symbol (floor function). Therefore, when the delay time τ is 28 hours, a = [0.5 × (1 + 2.33)] a = [1.667] a = 1, and the data period is a × 24 = 24 hours. Also, if the delay time τ is 37 hours, a = [2.042] a = 2, and the data period is a × 24 = 48 hours. Note that the calculation of the data period may be performed by the control table creation program itself, or may be performed by a person or another computer and input to the control table creation program.

[0023] Next, the control table creation program calculates the average value of the water quality information over the data period set in step S206 and sets it as the average water quality value T. The starting point of the data period at this time is the front-end value Cu or the rear-end value C that will be grouped later​Lτ This is related to, for example, the measurement of the front-end value Cu, but it is most preferable to do as follows. First, select the front-end value Cu to be grouped, and from the time of measurement of this front-end value Cu, select the back-end value C Lτ after a delay time τ. Lτ Then, calculate the average water quality value T with the point traced back by the data period from the time of measurement of this back-end value C Lτ as the starting point of the data period of the average water quality value T. That is, the average value of the water quality information in the data period with the measurement time of the back-end value C Lτ as the end point is taken as the average water quality value T (step S207). Then, group these front-end value Cu and back-end value C Lτ , and this average water quality value T (step S208).

[0024] Next, the control table creation program creates a data table having water quality value bands at equal intervals and front-end value bands at equal intervals as rows and columns (step S220). Here, these water quality value bands and front-end value bands are set to include the ranges of the average water quality value T and the front-end value Cu obtained by measurement. Also, the numerical width of one water quality value band and front-end value band may be fixed, or the ranges of the maximum value and minimum value of the average water quality value T and the front-end value Cu may be evenly divided into a predetermined number, for example, about 10 to 20, and set. Here, for example, when the average water quality value T (water temperature) is in the range of 2°C to 23°C, and the front-end value Cu (residual salt concentration) is in the range of 0.38 mg / L to 0.51 mg / L, the numerical width of the water quality value band is 1°C, and the numerical width of the front-end value band is 0.01 mg / L. If the central value of the water quality value band is Tn, the numerical range of one water quality value band is Tn ± 0.5°C, and Tn = 2, 3, ···, 23. Also, if the central value of each front-end value band is Cn, the numerical range of one front-end value band is Cn ± 0.005 mg / L, and Cn = 0.38, 0.39, ···, 0.51. That is, in this case, as shown in Fig. 4(a), the data table has the central value Tn of the water quality value band (Tn ± 0.5°C) set at 1°C intervals in the range of 2°C to 23°C, and the central value Cn of the front-end value band (Cn ± 0.005 mg / L) set at 0.01 mg / L intervals in the range of 0.38 mg / L to 0.51 mg / L.

[0025] Next, for each group data created in step S208, the control table creation program stores the trailing value C of the group data in the cell where the water quality value band to which the value of the average water quality value T belongs and the leading value band to which the value of the leading value Cu belongs intersect. Lτ For example, in the case of group data where the average water quality value T is 14.3 °C, the leading value Cu is 0.482 mg / L, and the trailing value C Lτ is 0.215 mg / L, 0.215 mg / L which is the trailing value C Lτ is stored in cell C of Fig. 4(b) where the water quality value band of 14 ± 0.5 °C and the leading value band of 0.48 ± 0.005 mg / L intersect. Then, these operations are performed for all group data (step S222).

[0026] Note that it is assumed that the management system to which the present invention is applied is already in actual operation. In this case, the trailing value C Lτ which is the water quality management item (residual salt concentration) at the target point E cannot be greatly deviated from the management target value (for example, 0.2 mg / L). Also, the leading value Cu does not greatly deviate from a predetermined range. For this reason, data of the trailing value C Lτ concentrates in a specific area of the data table, and in this area, multiple trailing values C Lτ are stored in one cell.

[0027] Also, the administrator increases the chemical dosage in summer when the water temperature is high and the reduction rate of the chlorine-based disinfectant is fast, and decreases the chemical dosage in winter when the water temperature is low and the reduction rate is slow, so as to maintain the water quality management item at the target point E near the management target value. For this reason, as shown in Fig. 4(b), in the water quality value band on the low-temperature side, although the cells of the leading value band with small numerical values (where the chemical dosage is small) are relatively easy to be filled, there is little corresponding group data and many blank cells in the cells of the leading value band with large numerical values (where the chemical dosage is large). On the contrary, in the water quality value band on the high-temperature side, although the cells of the leading value band with large numerical values (where the chemical dosage is large) are relatively easy to be filled, there is little corresponding group data and many blank cells in the cells of the leading value band with low numerical values (where the chemical dosage is small). Thus, there is a bias in the acquired group data, and there is a high possibility that blank cells will occur in some part.

[0028] Therefore, when there are blank cells in the data table (step S300: Yes), the control table creation program according to the present invention calculates the reduction rate coefficient k of all the trailing values C belonging to the water quality value band where the blank cells exist Lτ based on the following formula A (step S302). In the following formula A, Cn is the central value Cn of the leading value band to which the trailing value C Lτ belongs. k = (1 / τ) log e (Cn / C Lτ ) ··· (A)

[0029] Next, the control table creation program calculates the average value k ave of the calculated reduction rate coefficient k for each water quality value band (step S304).

[0030] Next, the control table creation program calculates the trailing value C Lτ of the blank cell according to the following formula B (trailing value calculation step S306). In the following formula B, Cn' is the central value Cn of the leading value band of the blank cell. C Lτ = Cn' · exp(-k ave · τ) ··· (B) Then, the control table creation program repeats these processes until there are no blank cells.

[0031] Then, when the trailing value C Lτ is stored in all cells of the data table and there are no blank cells (step S300: No), the control table creation program checks whether there is a cell in which a plurality of trailing values C Lτ are stored. Then, when there is a cell in which a plurality of trailing values C Lτ are stored (step S330: Yes), the average value of the trailing values C Lτ stored in that cell is set as the trailing value C Lτ of that cell (step S332). Then, these processes are repeated until there are no cells in which a plurality of trailing values C Lτ are stored.

[0032] As a result, as shown in FIG. 4(c), the trailing end value C is stored one by one in all cells of the data table (step S330: No). Then, the control table creation program uses this data table as the basic data table (basic table setting step S340). Incidentally, when the water quality management item of the target point (trailing end value C Lτ ) is maintained at a value near the management target value Ca throughout the year, in the basic data table, there are cells storing the trailing end value C L close to the management target value Ca in all water quality value bands. Therefore, in this case, this basic data table becomes the control table. However, depending on the acquired data, there may be a water quality value band where the trailing end value C Lτ deviates from the management target value Ca. Lτ

[0033] Therefore, next, the control table creation program checks the trailing end value C stored in the cell of the maximum leading end value band, and if any of these trailing end values C Lτ is less than the lower limit of the predetermined numerical range of the management target value Ca (step S344a: Yes), as shown in FIG. 5, the upper leading end value band is expanded in the direction of increasing numerical value to provide an expanded leading end value band Wb (step S346a). Then, it proceeds to step S348. Lτ

[0034] Here, for example, if the management target value Ca is 0.2 mg / L and the numerical range is ±0.005 mg / L, the lower limit of the numerical range of the management target value Ca is 0.195 mg / L. And in the basic data table of FIG. 4(c), the maximum leading end value band is the column with the central value Cn of 0.51 mg / L, and if any of the trailing end values C Lτ in this column is less than the lower limit value of the management target value Ca, an expanded leading end value band Wb is provided as shown in FIG. 5. Incidentally, in FIG. 5, since the trailing end value C Lτ of the maximum leading end value band all exceeds the lower limit value 0.195 mg / L of the numerical range of the management target value Ca, there is no need to provide an expanded leading end value band Wb, but for the sake of explanation, FIG. 5 shows an example where an expanded leading end value band Wb is provided.

[0035] Also, the trailing value C of the maximum leading value band Lτ If it exceeds all the lower limit values of the numerical range of the management target value Ca (step S344a: No), next, the control table creation program checks the trailing value C stored in the cell of the minimum leading value band of the basic data table Lτ and, if any of these trailing values C Lτ exceeds the upper limit value of the predetermined numerical range of the management target value Ca (step S344b: Yes), as shown in FIG. 5, the lower leading value band of the basic data table is expanded in the direction of smaller numerical values to provide an expanded leading value band Ws (step S346b). Then, the process proceeds to step S348. Here, in FIG. 4(c), the minimum leading value band is the column with the central value Cn of 0.38 mg / L, and the upper limit of the numerical range of the management target value Ca is 0.205 mg / L. And when checking the trailing value C Lτ of the column with 0.38 mg / L, the trailing value C Lτ of the water quality value band with the central value Tn of 2°C to 8°C is 0.207 mg / L or more and exceeds the upper limit value of 0.205 mg / L. Therefore, the control table creation program expands the lower leading value band to provide an expanded leading value band Ws. Note that all the cells of the expanded leading value bands Wb and Ws at the time of installation are blank cells.

[0036] Next, in step S348, the control table creation program calculates the trailing value C of the blank cells of the expanded leading value bands Wb and Ws expanded using the average value k ave of the decrease rate coefficient k calculated in step S304 in the same manner as in the trailing value calculation step S306. Then, the process proceeds to step S344a and these processes are repeated Lτ .

[0037] As a result, for example, in FIG. 5, the expansion of the downward expanded leading value band Ws is repeated until all the trailing values C Lτ of the water quality value band with the central value Tn of 2°C to 8°C are below the upper limit value of 0.205 mg / L, and finally the minimum leading value band becomes the expanded leading value band Ws with the central value Cn of 0.30 mg / L. In this way, the trailing value C that falls within the numerical range of the management target value Ca in all the water quality value bands LτThe expansion of the extended front-end value bands Wb and Ws is performed until is obtained, and the average value k of the decrease rate coefficient k ave of the trailing edge value C Lτ is calculated. Then, the trailing edge value C near the management target value Ca Lτ (the bold trailing edge value C in FIG. 5 Lτ ) is obtained in all water quality value bands (step S344b: No), and the control table creation program sets this as the final control table (step S334). Thereby, the creation of the control table Operation by the creation method according to the present invention and the control table creation program is completed.

[0038] Next, an explanation of the water quality control method according to the present invention using this control table will be given. The water quality control method according to the present invention has, as shown in FIG. 2(b), a setting step of determining the set value of the water quality management item at the chemical injection point using the control table, and a control step of controlling the chemical injection amount at the chemical injection point based on the set value determined in the setting step.

[0039] Here, FIG. 6 is a diagram showing the management value setting device 50 and the water quality control unit 30 for performing the water quality control method of the present invention. First, the management value setting device 50 of the present invention has a recording unit 52 in which at least the control table created as described above is recorded, and a control unit 54 that determines the set value of the water quality management item.

[0040] Further, the water quality control unit 30 has a management value measurement unit 32 that acquires the value of the management item (here, the residual salt concentration) at the chemical injection point P, a chemical injection unit 34 that injects a predetermined chemical into the chemical injection point P, and a control unit 36 that controls the operation of the chemical injection unit 34. The chemical injection unit 34 is preferably located upstream of the chemical injection point P, and the management value measurement unit 32 is preferably installed downstream of the chemical injection point P, particularly near the water outlet.

[0041] Then, in the water quality control method according to the present invention, first, the administrator inputs the management target value Ca of the water quality management item (residual salt concentration) at the target point E into the control unit 54 of the management value setting device 50 (step S390). Here, the management target value Ca input is the same value as the management target value Ca at the time of creating the control table. Therefore, here, the management target value Ca is set to 0.2 mg / L for the residual salt concentration.

[0042] Upon receiving the input of this management target value Ca, the control unit 54 refers to the control table recorded in the recording unit 52, and for each water quality value band, extracts the cell in which the trailing edge value C Lτ closest to the management target value Ca is stored. Here, since the control table is provided with an extended leading edge value band Wb and an extended leading edge value band Ws as needed, and the shortage area is supplemented, basically, the trailing edge value C Lτ of the extracted cell is within a predetermined numerical range close to the management target value Ca. Next, referring to the leading edge value band of the extracted cell, its central value Cn is extracted and used as a set value table corresponding to each water quality information (water temperature) (step S392). This set value table shows the residual salt concentration (management item) at the chemical agent injection point P when the residual salt concentration (management item) at the target point E after the elapse of the delay time τ is around the management target value Ca (residual salt concentration 0.2 mg / L) at a certain water temperature (water quality information).

[0043] Note that it is preferable that the water quality control unit 30 and the management value setting device 50 are configured by using existing equipment as much as possible or by adding functions. In particular, when a general-purpose PLC (Programmable Logic Controller) is used for the management value setting device 50, by inputting the above setting steps program and the control table into the management value setting device 50 (general-purpose PLC), the present invention can be introduced without incurring new equipment costs.

[0044] Next, the water quality information acquisition means 10 acquires the value of the water quality information (here, water temperature) of the management system and outputs it to the control unit 54 of the management value setting device 50 (step S400). Note that the water quality information acquisition means 10 does not necessarily have to be installed at the chemical agent injection point P, and it may be installed at an arbitrary location in the management system to acquire water quality information through communication or the like.

[0045] Next, the control unit 54 of the management value setting device 50 receives this water quality information and calculates the moving average over a preset data period to obtain the average water quality value T' during control (step S401). Note that the data period during this control does not necessarily have to be the same as the data period during control table creation. In order to eliminate the influence of sudden changes in the temperature of raw water due to sudden high temperatures, low temperatures, heavy rain, etc., it is preferably a relatively long period such as 3 days, 5 days, or 1 week.

[0046] Next, the control unit 54 of the management value setting device 50 refers to the setting value table at a preset time interval and selects the setting value R(n) corresponding to the average water quality value T' at that time. Then, the management value setting device 50 outputs this setting value R(n) to the water quality control unit 30 (step S402). Note that the output interval of this setting value R(n) is not particularly limited, such as every 12 hours, 1 day, 2 days, 3 days, etc., but it is preferably once a day.

[0047] Also, for example, when the data period during control cannot be made long, a low-pass filter may be used as shown in the following formula (D) to prevent sudden changes in the setting value. Here, α is a filter coefficient (fixed value), and is generally a numerical value in the range of about 0.1 to 0.4 around 0.3. R’(n)=α·R’(n - 1)+(1 - α)R(n)···(D) According to this configuration, even when the data period during control cannot be made long, it is possible to prevent the setting value R’(n) from changing significantly from the previous setting value R’(n - 1), and to prevent a large change in the setting value R(n) due to sudden abnormalities such as mismeasurements. And the above corresponds to the setting step of the water quality control method according to the present invention.

[0048] Next, the control unit 36 of the water quality control unit 30 receives the set value R(n) (or R’(n) when having a low-pass filter) from the management value setting device 50, and controls the chemical dosing unit 34 so that the value of the management item (residual salt concentration) acquired by the management value measurement unit 32 becomes the set value R(n), and adjusts the chemical dosing amount (step S404). Then, the water with the management item (residual salt concentration) set to the set value R(n) at the chemical dosing point P flows through the management system and reaches the target point E with an approximate delay time τ. At this time, although the residual salt concentration in the water decreases, since the residual salt concentration of the water discharged from the chemical dosing point P is adjusted to the set value R(n) considering the decrease, the residual salt concentration of the water when reaching the target point E will take a value near the management target value Ca of 0.2 mg / L.

[0049] And, for example, when the average water quality value T of the water quality information (water temperature) rises, the management value setting device 50 selects a relatively high numerical set value R(n) corresponding to this average water quality value T from the set value table and outputs it to the water quality control unit 30. The water quality control unit 30 receives this relatively high set value R(n) and increases the chemical dosing amount at the chemical dosing point P. Then, although the amount of decrease in the residual salt concentration of the water discharged from the chemical dosing point P is large due to the high water temperature (with a large chemical dosing amount), the residual salt concentration is correspondingly high, so the residual salt concentration at the target point E will be a value near the management target value Ca of 0.2 mg / L. Also, when the average water quality value T of the water quality information (water temperature) drops, the management value setting device 50 selects a relatively low numerical set value R(n) corresponding to this average water quality value T from the set value table and outputs it to the water quality control unit 30. The water quality control unit 30 receives this relatively low set value R(n) and decreases the chemical dosing amount at the chemical dosing point P. Then, although the amount of decrease in the residual salt concentration of the water discharged from the chemical dosing point P is small due to the low water temperature (with a small chemical dosing amount), the residual salt concentration at the time of chemical dosing is correspondingly low, so the residual salt concentration at the target point E will be a value near the management target value Ca of 0.2 mg / L.

[0050] In addition, when the management target value Ca changes due to a large change in water demand at the target point E, etc., the administrator extracts the trailing value C Lτ that is closest to the management target value Ca’ in each water quality value range of the control table LτCheck whether it is within the range of the preset management target value Ca'. Then, for the extracted trailing value C Lτ If all of them are within the range of the management target value Ca', the administrator inputs the changed management target value Ca' to the management value setting device 50. As a result, the management value setting device 50 extracts the stored cell of the trailing value C Lτ closest to the changed management target value Ca' for each water quality value band, extracts the central value Cn of the leading value band of that cell, and uses this as a new setting value table. Thereby, the management item at the target point E is maintained at a value near the new management target value Ca'.

[0051] Also, if any of the extracted trailing values C Lτ is outside the range of the management target value Ca' even partially, perform steps S344a to S334 with the changed management target value Ca'. As a result, an extended leading value band Wb or an extended leading value band Ws is provided in the control table, and in the same way, the trailing value C Lτ within the range of the management target value Ca' is calculated.

[0052] The control table corrected in this way is recorded in the recording unit 52 of the management value setting device 50. When the administrator inputs a new management target value Ca', the management value setting device 50 extracts the setting value table corresponding to the changed management target value Ca' and outputs the setting value R(n). Thereby, the management item at the target point E is maintained at a value near the new management target value Ca'.

[0053] In addition, water quality information, leading value Cu, trailing value C L are often monitored all the time. Therefore, for example, when an average water quality value T exceeding the range of the water quality value band of the existing control table is obtained, the control table can be supplemented taking this data into account and transmitted to the management value setting device 50 to automatically update the control table.

[0054] As described above, the control table according to the present invention OperationThe control method and the control table creation program create a control table using the measured data in the actual operation management system. Also, for the insufficient parts, they are calculated by operations based on the measured data. Therefore, it is possible to acquire measurement data while operating the management system. Also, it is possible to create a control table without using expensive devices such as AI devices. Furthermore, the data necessary for creating the control table are basically items that are generally monitored in the management system, and no new equipment is required for data acquisition. Therefore, it is generally possible to respond with existing equipment and keep the introduction cost low.

[0055] Also, in the water quality control method according to the present invention, based on the control table derived from the measured data in the actual management system as described above, the value of the optimal water quality management item (residual salt concentration) at the chemical injection point P is set. Then, by controlling the chemical injection amount so that the water quality control unit 30 reaches the set value of the water quality management item, it is possible to maintain the water quality management item (residual salt concentration) near the appropriate management target value Ca at the target point E far downstream from the chemical injection point P.

[0056] Note that the control table is basically calculated and completed by another computer and recorded in the management value setting device 50 for use. Also, since the management value setting device 50 only refers to this control table as needed, no large computational load is generated on the management value setting device 50 side. Therefore, the management value setting device 50 does not require expensive devices capable of complex operations, and devices such as general-purpose PLCs that are commonly used in the control of chemical injection amounts can be used. And when a general-purpose PLC is used as the management value setting device 50, by inputting the program for performing the above-described setting step and the control table into the management value setting device 50, it is possible to introduce the water quality control method according to the present invention only with the existing equipment without providing new equipment. Also, even when newly introducing the management value setting device 50, inexpensive devices can be used. Thereby, the introduction cost of the present invention can be extremely low.

[0057] And the control table according to the present inventionOperation According to the forming method, the control table creation program, and the water quality control method, the management value setting device 50 and the water quality control unit 30 automatically adjust the value (residual salt concentration) of the water quality management item associated with the change in water quality information, which was conventionally performed by the administrator based on experience. As a result, the burden on the administrator can be reduced and labor costs can be cut. In addition, since the adjustment of the value of the water quality management item is performed based on the control table based on the actual measurement data in the actual management system, more appropriate control can be performed than the conventional adjustment by the administrator. Furthermore, this adjustment operation can be periodically performed at preset intervals. Therefore, appropriate management can be continuously performed throughout the year.

[0058] Note that the control table shown in this example Operation The forming method, the control table creation program, and the water quality control method are examples, and each step, the configuration and order of the processing, the acquisition method of each data, etc., the device configuration, the operation, etc. can be changed and implemented without departing from the gist of the present invention.

Explanation of Signs

[0059] 30 Water quality control unit 32 Management value measurement unit 34 Chemical agent injection unit 36 Control unit 50 Management value setting device 52 Recording unit 54 Control unit P Chemical agent injection point E Target point S306 Rear-end value calculation step S340 Basic table setting step

Claims

1. A control table creation method for creating a control table for controlling the chemical dosage at the chemical injection point of a management system, comprising: a step of setting, by existing equipment installed in the management system, the water quality management items at the chemical injection point and the target point downstream, monitoring the water quality management items at the chemical injection point and the target point downstream, and setting the arrival time from the chemical injection point to the target point as a delay time τ based on the change in the water quality management items; a step of obtaining, by existing equipment installed in the management system, the water quality information of the management system for a predetermined period; a step of obtaining, for a predetermined period, the value of the water quality management item at the chemical injection point as a front-end value Cu; The step of obtaining, for a predetermined period, the value of the water quality management item at the target location as the backend value C Ｌ is performed, a step of calculating, by a computer on which a control table creation program is started, an average water quality value T of the water quality information for a predetermined data period; Each front-end value Cu and the rear-end value C after the elapse of the delay time τ from the measurement of the front-end value Cu Ｌτ and the front-end value Cu or the rear-end value C Ｌτ and the step of grouping the average water quality value T associated therewith a step of creating a data table having, as rows and columns, an equally spaced water quality value band corresponding to the average water quality value T and an equally spaced front-end value band corresponding to the front-end value Cu, and setting a center value Cn for each front-end value band; For the data table, a rear end value C is stored in a cell where a water quality value band to which an average water quality value T of the group data belongs and a front end value band to which a front end value Cu belongs intersect Ｌτ and a step of storing it When there are blank cells in the data table, for all trailing values C of the water quality value range where the blank cells exist Ｌτ calculate the decrease rate coefficient k of each trailing value C Ｌτ using the central value Cn of the leading value range to which each belongs, according to the following formula A k = (1 / τ) log ｅ (Cn / C Ｌτ )... (A) The average value k of the decay rate coefficient k for each water quality value range ａｖｅ and the step of calculating The trailing end value C of the blank cell Ｌτ A trailing end value calculation step of calculating by the following formula B using the central value Cn' of the leading end value range to which the blank cell belongs, C Ｌτ = Cn'·exp( - k ａｖｅ ·τ)···(B) When a plurality of backend values C are stored in one cell Ｌτ if so, the stored backend value C Ｌτ is set as the backend value C of that cell Ｌτ and the step of doing so a basic table setting step of using the data table as a basic data table, wherein the control table creation method is characterized by performing the above steps.

2. a step of setting, for a computer, a management target value Ca of the water quality management item at the target point; the computer, after the basic table setting step, The trailing value C of the maximum leading value range of the basic data table Ｌτ When it is less than the lower limit of the predetermined numerical range of the management target value Ca, expanding the leading value range of the upper limit of the data table in the direction of increasing numerical values to provide an expanded leading value range; The trailing value C of the minimum leading value band of the basic data table Ｌτ When it exceeds the upper limit of the predetermined numerical range of the management target value Ca, expanding the leading value band at the lower limit of the data table in the direction of smaller numerical values to provide an expanded leading value band; The trailing end value C of the cell in the extended leading end value band Ｌτ calculating based on a trailing end value calculation step; and performing the method for creating a control table according to claim 1, characterized by the above steps.

3. A control table creation program for creating a control table for controlling the chemical dosage at the chemical injection point of a management system, comprising: The data of the water quality information of the management system acquired in advance over a predetermined period, the data of the front-end value Cu as the value of the water quality management item at the chemical injection point, and the data of the rear-end value C as the value of the water quality management item at the target point Ｌ The process of reading the data of a process of obtaining a data period for calculating an average water quality value T that is the average value of water quality information; a process of calculating the average water quality value T of the water quality information using the data period; Each front-end value Cu and a rear-end value C after a preset delay time τ has elapsed since the measurement of the front-end value Cu Ｌτ and the front-end value Cu or the rear-end value C Ｌτ and the average water quality value T associated therewith, and a process of grouping them into group data a process of creating a data table having, as rows and columns, an equally spaced water quality value band corresponding to the average water quality value T and an equally spaced front-end value band corresponding to the front-end value Cu, and setting a center value Cn for each front-end value band; For the data table, a process of storing the trailing value C in a cell where the water quality value band to which the average water quality value T of the group data belongs intersects with the leading value band to which the leading value Cu belongs Ｌτ and When there are blank cells in the data table, for all the trailing values C of the water quality value range where the blank cells exist Ｌτ the decrease rate coefficient k is calculated based on the following formula A using the central value Cn of the leading value range to which each trailing value C Ｌτ belongs, and the process of calculating k = (1 / τ) log ｅ (Cn / C Ｌτ )... (A) The average value k of the reduction rate coefficient k for each water quality value range ａｖｅ The process of calculating it, and The trailing end value C of the blank cell Ｌτ is calculated by the following formula B using the center value Cn' of the leading end value range to which the blank cell belongs, and a trailing end value calculation process C Ｌτ = Cn' · exp( - k ａｖｅ · τ) ··· (B) When a plurality of backend values C are stored in one cell Ｌτ if so, the average value of the stored backend values C Ｌτ is set as the backend value C of that cell Ｌτ and the process of a basic table setting process of using the data table as a basic data table, wherein the control table creation program is characterized by causing a computer to execute the above processes.

4. a process of setting a management target value Ca of the water quality management item at the target point; after the basic table setting process, The trailing value C of the maximum leading value range of the basic data table Ｌτ When it is less than the lower limit of the predetermined numerical range of the management target value Ca, a process of expanding the leading value range of the upper limit of the data table in the direction of increasing numerical value to provide an expanded leading value range, The trailing value C of the minimum leading value range of the basic data table Ｌτ When it exceeds the upper limit of the predetermined numerical range of the management target value Ca, a process of expanding the leading value range of the lower limit of the data table in the direction of smaller numerical values to provide an expanded leading value range, The trailing value C of the cell in the extended leading value band Ｌτ The control table creation program according to claim 3, wherein the computer is caused to execute a process of calculating the trailing value C based on a trailing value calculation process.

5. A water quality control method for controlling the value of the water quality management item at the target point using the control table created by the control table creation method according to Claim 1 or Claim 2, comprising: a setting step of determining a set value of the water quality management item at the chemical injection point; A control step of controlling the dosage of the chemical agent so that the value of the water quality management item at the chemical agent input point becomes the set value, The setting step includes: A step of setting a management target value of the water quality management item at the target point; Among the control tables, the trailing end value C of the value closest to the management target value Ｌτ extracting the stored cells for each water quality value band, and creating a set value table by setting the central value Cn of the leading end value band of the cells as the set value for each water quality value band; A step of obtaining the value of the water quality information of the management system and calculating the average water quality value T' at the time of control; A step of referring to the set value table, selecting the set value corresponding to the water quality value range to which the average water quality value T' belongs, and setting it as the set value of the control step; A water quality control method characterized by comprising the above steps.

6. Equipped with a management value setting device that performs the setting step, The management value setting device includes a recording unit in which at least a control table is recorded, and a control unit that creates a set value table and determines the set value of the control step based on the average water quality value T'. The water quality control method according to claim 5, characterized by comprising the above steps.

7. Equipped with a water quality control unit that performs the control step, The water quality control unit includes a management value measurement unit that obtains the value of the management item at the chemical agent input point, a chemical agent input unit that inputs the chemical agent at the chemical agent input point, and the value of the water quality management item obtained from the management value measurement unit is the set value determined by the management value setting device. And a control unit that controls the operation of the chemical agent input unit. The water quality control method according to claim 6, characterized by comprising the above steps.

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