Information processing device, control content determination method, control system, and control content determination program

Abstract

To discharge an amount of nutrient salts corresponding to an amount of a requested discharge, while keeping a concentration of the discharged nutrient salts and a total amount of discharge in a specified period to be below a regulated value.SOLUTION: An information processing device (1) includes a data acquisition unit (101) that acquires status information (111) indicating a status of sewage being treated in a sewage treatment facility, and a control content determination unit (102) that determines a content of control to be applied to the treatment of the sewage, in which the control content determination unit (102) determines the content of the control by obtaining a value of a variable so that the amount of nutrient salts discharged represented by a variable indicating the content of the control and the status information (111) corresponds to a target value; and the target value is a value that is determined so that a concentration of the nutrient salts discharged and a total discharge amount are equal to or less than a regulated value, and so that the amount of nutrient salts corresponding to the requested discharge amount is discharged.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an information processing device that determines the details of control in a sewage treatment facility. [Background technology]

[0002] There are known techniques for automatically controlling the water treatment process in a sewage treatment plant. For example, the following Patent Document 1 discloses a water treatment device that satisfies the quality of treated water while minimizing the pollutant load discharged. Specifically, this water treatment device sets the flow rate of inflow water to the reaction tank based on an estimated value of the pollutant concentration in the reaction tank effluent water and an estimated value of the pollutant load discharged from the water treatment process. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2018-138289 A Summary of the Invention [Problem to be solved by the invention]

[0004] Here, the sludge material to be removed by the water treatment device of Patent Document 1 contains nutrients such as nitrogen and phosphorus. Discharging a large amount of nutrients is undesirable because it leads to eutrophication of the water area, but releasing water containing a moderate amount of nutrients has a positive effect on the growth of organisms in the water area. In other words, from the perspective of maintaining good growth of organisms in the water area, sewage treatment plants are required to release a moderate amount of nutrients.

[0005] However, in Patent Document 1, "satisfying the treated water quality" means that the pollutant concentration in the treated water does not exceed the planned discharge water quality. Therefore, when using the water treatment device of Patent Document 1, there is a possibility that the amount of nutrient salt discharged will be too low. And if the amount of nutrient salt discharged is too low, the water area into which the treated water is discharged may become oligotrophic, which may have a negative impact on the growth of organisms living in the water area.

[0006] One aspect of the present invention aims to realize an information processing device or the like that enables the discharge of an amount of nutrients according to a requested discharge amount while keeping the concentration of the nutrients discharged and the total discharge amount in a specified period below regulated values. [Means for solving the problem]

[0007] In order to solve the above problems, an information processing device according to one embodiment of the present invention includes a data acquisition unit that acquires status information indicating the state of sewage treated in a sewage treatment facility, and a control content determination unit that determines the content of control to be applied to the treatment of the sewage, and the control content determination unit determines the content of control to be applied to the treatment of the sewage by calculating the value of a variable that indicates the content of the control and the status information, such that the amount of nutrients discharged from the sewage treatment facility corresponds to a predetermined target value, and the target value is a value that is determined so that the concentration of nutrients discharged from the sewage treatment facility and the total discharge in a predetermined period of time are below a regulated value, and an amount of nutrients corresponding to a discharge request amount for the sewage treatment facility is discharged.

[0008] In order to solve the above problem, another information processing device according to one embodiment of the present invention includes a data acquisition unit that acquires status information indicating the state of sewage being treated in a sewage treatment facility, and a control content determination unit that determines the content of control to be applied to the treatment of the sewage, and the control content determination unit determines the content of control corresponding to the state indicated by the status information in accordance with a strategy generated by reinforcement learning that gives a reward according to the degree of deviation between the amount of nutrients discharged from the sewage treatment facility after the control and a predetermined target value, for a combination of the state of the sewage being treated and the content of control performed in that state, and the target value is a value determined so that the concentration of nutrients discharged from the sewage treatment facility and the total discharge in a predetermined period of time are below a regulated value, and an amount of nutrients corresponding to the discharge request amount for the sewage treatment facility is discharged.

[0009] In order to solve the above problem, yet another information processing device according to one embodiment of the present invention includes a data acquisition unit that acquires an actual value of a nutrient discharge amount from a sewage treatment facility or a predicted value of the discharge amount, and a control content determination unit that determines a control content to be applied to sewage treatment at the sewage treatment facility based on a difference between the actual value or the predicted value and a predetermined target value, wherein the target value is a value determined so that the concentration of nutrients discharged from the sewage treatment facility and the total discharge amount in a predetermined period are equal to or less than a regulated value, and so that an amount of nutrients corresponding to a discharge amount requested to the sewage treatment facility is discharged.

[0010] In order to solve the above problem, yet another information processing device according to one embodiment of the present invention includes a data acquisition unit that acquires an actual value of a nutrient discharge amount from a sewage treatment facility at a certain point in time or a predicted value of the discharge amount, a target correction unit that corrects a target value from the point in time onwards based on a difference between the actual value or the predicted value and a target value previously set for the point in time, and a control content determination unit that determines a control content to be applied to sewage treatment so that the nutrient discharge amount from the sewage treatment facility approaches the corrected target value, wherein the target value is a value determined so that the concentration of nutrients discharged from the sewage treatment facility and the total discharge amount in a predetermined period are equal to or less than a regulated value and an amount of nutrients corresponding to a discharge request amount for the sewage treatment facility is discharged.

[0011] In order to solve the above problems, a control content determination method according to one embodiment of the present invention is a control content determination method executed by one or more information processing devices, and includes a data acquisition step of acquiring status information indicating the state of sewage treated in a sewage treatment facility, and a control content determination step of determining control content to be applied to the treatment of the sewage, in which the control content determination step determines the control content to be applied to the treatment of the sewage by calculating values ​​of variables indicating the control content and the status information such that the amount of nutrients discharged from the sewage treatment facility corresponds to a predetermined target value, and the target value is a value determined such that the concentration of nutrients discharged from the sewage treatment facility and the total discharge in a predetermined period are below a regulated value, and an amount of nutrients corresponding to a discharge request amount for the sewage treatment facility is discharged.

[0012] In order to solve the above problems, a control system according to one embodiment of the present invention includes an information processing device that acquires status information indicating the state of sewage treated in a sewage treatment facility and determines the content of control to be applied to the treatment of the sewage, and a control device that controls the treatment of the sewage in accordance with the decision of the information processing device, wherein the information processing device determines the content of control to be applied to the treatment of the sewage by calculating the value of a variable that indicates the content of the control and the status information, such that the amount of nutrients discharged from the sewage treatment facility corresponds to a predetermined target value, and the target value is a value that is determined so that the concentration of nutrients discharged from the sewage treatment facility and the total discharge in a predetermined period of time are below a regulated value, and an amount of nutrients corresponding to a discharge request amount for the sewage treatment facility is discharged. Effect of the Invention

[0013] According to one aspect of the present invention, it is possible to discharge an amount of nutrients according to a requested discharge amount while keeping the concentration of the discharged nutrients and the total discharge amount in a specified period at or below regulated values. [Brief description of the drawings]

[0014] [Figure 1] 1 is a block diagram showing an example of a configuration of a main part of an information processing device according to a first embodiment of the present invention. [Diagram 2] FIG. 1 is a diagram showing a configuration of a control system according to a first embodiment of the present invention. [Diagram 3] FIG. 11 is a diagram showing an example of discharge plan information. [Figure 4] 4 is a flowchart showing an example of processing executed by the information processing device according to the first embodiment of the present invention. [Diagram 5] FIG. 11 is a block diagram showing an example of a configuration of a main part of an information processing device according to a second embodiment of the present invention. [Figure 6] FIG. 11 is a block diagram showing an example of a configuration of a main part of an information processing device according to a third embodiment of the present invention. [Figure 7] FIG. 11 is a diagram illustrating the timing of adjustment of control contents. [Figure 8] 11 is a flowchart showing an example of processing executed by an information processing device according to a third embodiment of the present invention. [Figure 9] FIG. 11 is a block diagram showing an example of a configuration of a main part of an information processing device according to a fourth embodiment of the present invention. [Figure 10] FIG. 13 is a diagram illustrating an example of correction of a target value. [Figure 11] 11 is a flowchart showing an example of processing executed by an information processing device according to a fourth embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] [Embodiment 1] (Device configuration) The configuration of an information processing device 1 according to this embodiment will be described with reference to Fig. 1. Fig. 1 is a block diagram showing an example of the configuration of the main parts of the information processing device 1. The information processing device 1 is a device having a function of determining the content of control to be applied to sewage treatment in a sewage treatment facility. As shown in the figure, the information processing device 1 includes a control unit 10 that controls each part of the information processing device 1 in an integrated manner, and a storage unit 11 that stores various data used by the information processing device 1. The information processing device 1 also includes a communication unit 12 that allows the information processing device 1 to communicate with other devices, an input unit 13 that accepts input to the information processing device 1, and an output unit 14 that allows the information processing device 1 to output various data.

[0016] Moreover, control unit 10 includes data acquisition unit 101, control content determination unit 102, and facility control unit 103. Moreover, storage unit 11 stores state information 111, discharge plan information 112, and value function 113. Note that value function 113 will be described later in the section "Regarding determination of control content using value function."

[0017] The data acquisition unit 101 acquires status information indicating the status of sewage being treated in a sewage treatment facility. The data acquisition unit 101 then stores the acquired status information in the storage unit 11 as status information 111.

[0018] As described above, the status information 111 is information indicating the status of the sewage treated in the sewage treatment facility. For example, the status information 111 may indicate at least one of the temperature, inflow amount, dissolved oxygen concentration, biochemical oxygen demand, amount of contained nutrients, and precipitation (e.g., accumulated rainfall in the last 24 hours) of the sewage to be treated (which may also be referred to as inflow water flowing into the sewage treatment facility). The amount of nutrients may be either or both of the amount of nitrogen and the amount of phosphorus, or may be the total amount of nitrogen and the amount of phosphorus. The amount of nutrients in the status information 111 does not necessarily need to be an actual measurement value, and past actual values ​​or average values ​​in a nearby period may be applied as the amount of nutrients.

[0019] The status information 111 may also include information indicating the status of the sewage being treated. For example, the status information 111 may include information indicating the oxidation-reduction potential in the anoxic tank shown in Fig. 2, which will be described later, the dissolved oxygen concentration in the aerobic tank also shown in Fig. 2, the water temperature, and the concentration of activated sludge suspended solids.

[0020] The control content determination unit 102 determines the content of control to be applied to the treatment of sewage in the sewage treatment facility. More specifically, the control content determination unit 102 determines the content of control to be applied to the treatment of sewage by calculating the value of variables that will cause the amount of nutrient salt discharged from the sewage treatment facility, represented by using variables indicating the content of control and state information, to become a value corresponding to a predetermined target value. Note that the "value corresponding to the target value" is a value that is the same as or close to the target value, and is at least a value that is closer to the target value than the value before the control is performed. Note that the control to be applied to the treatment of sewage will be described later in the section "System Configuration."

[0021] Here, the target values ​​are values ​​determined so that the concentration of nutrients discharged from the sewage treatment facility and the total discharge amount in a specified period are equal to or less than the regulated value, and so that the amount of nutrients discharged corresponds to the discharge amount requested to the sewage treatment facility. Since the amount of nutrients discharged varies depending on the time of year, it is desirable to set the target values ​​different for each time of year. The regulated value of the nutrient concentration may be, for example, the planned discharge water quality (the upper limit regulated value of the daily average nutrient concentration). Also, the regulated value of the total discharge amount of nutrients may be, for example, a value determined based on the planned treated water quality (the upper limit regulated value of the annual average nutrient concentration).

[0022] The discharge plan information 112 is information that defines target values ​​for the amount of nutrient discharged for each period. The control content determination unit 102 can specify target values ​​according to the period by referring to the discharge plan information 112. Details of the discharge plan information 112 will be explained later in the section "Regarding the discharge plan information."

[0023] The facility control unit 103 controls various devices installed in the sewage treatment facility in accordance with the decision made by the control content decision unit 102. The devices to be controlled and the control method will be described later in the section "System Configuration".

[0024] As described above, the information processing device 1 includes a data acquisition unit 101 that acquires status information 111 indicating the status of sewage treated in the sewage treatment facility, and a control content determination unit 102 that determines the content of control to be applied to the treatment of the sewage. The control content determination unit 102 determines the content of control to be applied to the treatment of the sewage by calculating the value of a variable that makes the amount of nutrient discharged from the sewage treatment facility, represented by using the variable indicating the content of control and the status information 111, correspond to a predetermined target value. The target value is a value determined so that the concentration of nutrient discharged from the sewage treatment facility and the total discharge in a predetermined period are equal to or less than a regulated value, and an amount of nutrient discharged corresponds to a discharge amount requested to the sewage treatment facility.

[0025] Therefore, according to the information processing device 1, it is possible to discharge an amount of nutrients according to a requested discharge amount while keeping the concentration of nutrients discharged from a sewage treatment facility and the total discharge amount in a predetermined period below the regulated value.

[0026] (System Configuration) 2 is a diagram showing the configuration of a control system 9 according to this embodiment. As shown in the figure, the control system 9 includes, in addition to the above-mentioned information processing device 1, a control device 2, a blower 3, a chemical additive device 4, an excess sludge extraction pump 5, and a circulation pump 6. The blower 3, the chemical additive device 4, the excess sludge extraction pump 5, and the circulation pump 6 are all devices to be controlled in the sewage treatment facility. Note that the control system 9 may include, instead of the information processing device 1, any of the information processing devices 1A to 1C according to embodiments 2 to 4 described below.

[0027] The control device 2 is a device that controls each device to be controlled, and controls the sewage treatment according to the contents determined by the information processing device 1. In other words, the facility control unit 103 of the information processing device 1 can control each device via the control device 2. Note that a control device 2 may be provided for each device to be controlled. Also, the control device 2 may be omitted, and the information processing device 1 may directly control each device.

[0028] Below, each piece of equipment is explained along with the flow of sewage treatment. Figure 2 shows equipment that uses biological phosphorus removal and biological nitrogen removal to remove the nutrients phosphorus and nitrogen from influent water that flows into a sewage treatment facility. The biological phosphorus removal process is a method of removing phosphorus from influent water using polyphosphate accumulating bacteria, which are bacteria that take up phosphorus. The biological nitrogen removal process is a method of removing nitrogen from influent water by oxidizing nitrogen compounds in the influent water with nitrifying bacteria to turn them into nitrate nitrogen, and then reducing this nitrate nitrogen to nitrogen gas with denitrifying bacteria.

[0029] Influent water that flows into a sewage treatment plant is sent to the anaerobic tank, which is one of the treatment tanks divided into an anaerobic tank, an anoxic tank, and an aerobic tank. Under anaerobic conditions, polyphosphate-accumulating bacteria take in organic matter and excrete polyphosphate in return.

[0030] Next, the influent is sent from the anaerobic tank to the aerobic tank via the anoxic tank. Air is sent into the aerobic tank by a blower 3. In the aerobic tank, the polyphosphate accumulating bacteria take in more polyphosphate than they released in the anaerobic tank. This increases the phosphorus content in the bodies of the polyphosphate accumulating bacteria in the activated sludge, while the phosphorus concentration in the influent decreases. The influent with a reduced phosphorus concentration and the activated sludge mixture are then separated by a solid-liquid separator. As a result, the phosphorus concentration in the treated water can be reduced to the desired level. The polyphosphate accumulating bacteria that have taken in excess phosphorus are removed from the treatment tank by a surplus removal pump 5.

[0031] In addition, by using the chemical additive device 4 to introduce a chemical (e.g., polyaluminum chloride) that has the effect of electrically adsorbing soluble phosphorus to the activated sludge into the aerobic tank, the soluble phosphorus contained in the influent is adsorbed by the activated sludge, and the mixture of the influent and activated sludge is separated using a solid-liquid separator, so that the phosphorus in the treated water can be reduced to the desired concentration.

[0032] In the aerobic tank, where the conditions are aerobic, nitrifying bacteria oxidize nitrogen compounds such as ammonia contained in the inflow water to nitrate nitrogen. The mixture of inflow water and activated sludge containing this nitrate nitrogen is called nitrification liquid. The nitrification liquid is sent to the anoxic tank by a circulation pump 6. Since denitrifying bacteria reduce nitrate nitrogen to nitrogen gas in an anaerobic state, the nitrate nitrogen generated by nitrification in the aerobic tank becomes nitrogen gas in the anoxic tank and is released into the air. In this way, by circulating the treated water between the anoxic tank and the aerobic tank, the nitrogen in the inflow water can also be reduced to a desired concentration. After the treatment in the treatment tank, the water is subjected to sterilization and other treatments in the treatment water tank before being discharged from the sewage treatment facility.

[0033] The amount of air blown by the blower 3, the amount of chemical added by the chemical adder 4, the amount of excess sludge extracted by the excess sludge extraction pump 5, and the amount circulated by the circulation pump 6 all affect the concentration of at least one of phosphorus and nitrogen in the treated water. Therefore, the control content determination unit 102 may determine the control content for these devices. In this case, the devices to be used and the control content for the devices may be represented by variables, and the control content determination unit 102 may calculate the value of this variable. Then, the facility control unit 103 may control these devices according to the determined control content. This makes it possible to adjust the amount of nutrient discharged.

[0034] For example, in a situation where it is desired to increase the amount of nutrients discharged, the control content determination unit 102 may determine to perform control to reduce the amount of circulation by the circulation pump 6 to a predetermined value. In this case, the facility control unit 103 instructs the control device 2 to reduce the amount of circulation by the circulation pump 6 to a predetermined value. This reduces the amount of nutrients removed in the nutrient removal tank, and accordingly, the amount of nutrients discharged from the sewage treatment facility can be increased.

[0035] The configuration of the sewage treatment facility, the method of sewage treatment, and the equipment to be controlled are arbitrary and are not limited to the example of FIG. 2. For example, the sewage treatment facility may be equipped with both a first purification facility having a function of removing phosphorus and nitrogen from sewage and a second purification facility having a low (or no) ability to remove phosphorus and nitrogen. In this case, the control content determination unit 102 may determine to send sewage to the second purification facility when it is desired to increase the amount of nutrient salt discharged and not to use the first purification facility. Conversely, when it is desired to decrease the amount of nutrient salt discharged, the control content determination unit 102 may determine to send sewage to the first purification facility and not to use the second purification facility. In general, purification facilities having a low or no ability to remove nutrients have lower operating costs than purification facilities having the ability to remove nutrients, so it is possible to reduce the cost of sewage treatment by appropriately using these purification facilities.

[0036] As described above, the control system 9 includes the information processing device 1 that acquires the status information 111 indicating the status of the sewage treated in the sewage treatment facility and determines the content of the control to be applied to the treatment of the sewage, and the control device 2 that controls the treatment of the sewage according to the determination of the information processing device 1. The information processing device 1 determines the content of the control to be applied to the treatment of the sewage by calculating the value of a variable that makes the discharge amount of nutrients from the sewage treatment facility, which is expressed using the variables indicating the content of the control and the status information 111, a value corresponding to a predetermined target value. The target value is a value that is determined so that the concentration of nutrients discharged from the sewage treatment facility and the total discharge amount in a predetermined period are equal to or less than the regulation value, and the amount of nutrients is discharged according to the discharge amount requested to the sewage treatment facility. Therefore, it is possible to discharge the amount of nutrients according to the discharge amount while keeping the concentration of the nutrients discharged and the total discharge amount in a predetermined period below the regulation value.

[0037] (About emission plan information) As described above, the target values ​​used in determining the control content are set so that the concentration of nutrients discharged from the sewage treatment facility and the total discharge amount in a specified period are equal to or less than the regulated value, and the amount of nutrients discharged corresponds to the discharge amount requested to the sewage treatment facility. The discharge plan information 112 is information indicating the target value for each period. The discharge plan information 112 may be information indicating the target value of the amount of nutrients discharged for each month or day in a year, for example, or may be information indicating the target value of the amount of nutrients discharged for each hour.

[0038] Fig. 3 is a diagram showing an example of the discharge plan information 112. 112a and 112b shown in Fig. 3 are both examples of the discharge plan information 112, and show target values ​​of nutrient discharge amounts for each month in a year. In the discharge plan information 112a, the target values ​​for summer and winter are set to constant values, and the target value for winter is set to a value larger than the target value for summer. Such target values ​​for each period are generally determined through discussion with, for example, neighboring local governments, fishery-related parties, etc.

[0039] Here, the target value for each day is set so that the average nutrient discharge concentration for one day is equal to or lower than a regulated value (e.g., the planned effluent quality). By controlling the sewage treatment facility according to the target value set in this way, the concentration of nutrient discharged can be maintained at or below the regulated value. Considering that there may be times when the actual discharge amount is greater than the target value, it is preferable to set the target value so that the average daily discharge concentration calculated from the target value is lower than the planned effluent quality (e.g., about 80% or 90% of the planned effluent quality).

[0040] Then, by connecting the target values ​​for summer and winter, discharge plan information 112a showing a discharge plan for one year can be created. Specifically, the discharge plan information 112a is created by connecting the target value for the last month of summer with the target value for the first month of winter with a straight line, and by connecting the target value for the last month of winter with the target value for the first month of the following summer (not shown in the graph) with a straight line. As a result, in the discharge plan information 112a, the target value increases in proportion to time during the preparation period from the last month of summer to the first month of winter, and decreases in proportion to time during the recovery period from the last month of winter to the first month of the following summer.

[0041] When creating the discharge plan information 112a, a limit may be placed on the slope (rate of change) in the preparation and recovery periods. In this case, the period of at least one of the summer and winter periods may be lengthened or shortened to balance the figures. In addition, the method of connecting the target values ​​in summer and winter (in other words, the method of setting the target values ​​in the preparation and recovery periods) is arbitrary, and for example, the target values ​​in summer and winter may be connected by a B-spline curve or a sigmoid function.

[0042] Furthermore, the target values ​​for each period are set so that the cumulative value of the target values ​​for one year is equal to or less than the regulated value for the total annual discharge (for example, the upper limit of the total annual discharge calculated from the planned treated water quality). By controlling the sewage treatment facility according to the target values ​​set in this way, the total discharge for a given period (one year in this example) can be kept below the regulated value.

[0043] The discharge plan information 112a may be created manually or by the information processing device 1. In the latter case, a plan information generating unit that generates the discharge plan information 112 may be provided in the control unit 10 of the information processing device 1. When the plan information generating unit generates the discharge plan information 112, the information processing device 1 may accept, for example, the designation of the rate of change of the target value in the preparation period and the recovery period, the maximum value of the target value, the minimum value of the target value, the period for maintaining the predetermined target value, the kurtosis, the skewness, and the like. In this case, the plan information generating unit generates the discharge plan information 112 that satisfies the designated conditions.

[0044] Furthermore, a search algorithm such as the A-star algorithm can also be used as a method for generating the emission plan information 112. The emission plan information 112b shown in Fig. 3 shows an example of the emission plan information 112 generated by the A-star algorithm. When the A-star algorithm is applied, as shown in Fig. 3, the plan information generation unit masks undesirable areas in the graph area (areas where the difference from the emission request amount is a predetermined value or more, areas where the emission amount is a regulated value or more, etc.). Then, the plan information generation unit finds a curve that connects the unmasked areas from the first day to the last day of the period in the shortest distance, and sets this as the emission plan information 112b.

[0045] Furthermore, when data showing past discharge results exists, the data can be used to generate the discharge plan information 112. For example, the plan information generating unit may obtain data showing discharge results over multiple years in which the concentration of nutrients discharged from the sewage treatment facility and the total discharge amount in a predetermined period are below the regulated value, and an amount of nutrients corresponding to the discharge amount requested to the sewage treatment facility is discharged. The plan information generating unit may then generate discharge plan information 112 in which the average value of the discharge amount for each month shown in the data is set as the target value for each month.

[0046] The plan information generating unit may generate the discharge plan information 112 for each type of nutrient salt. For example, the plan information generating unit may generate the discharge plan information 112 for nitrogen and the discharge plan information 112 for phosphorus. The discharge plan information 112 shown in Fig. 3 indicates a target value of the discharge amount of nutrients per hour, but the discharge plan information 112 may also indicate a target value of the cumulative discharge amount of nutrients per hour (the cumulative discharge amount from the start of the period for which the annual discharge amount is calculated).

[0047] (Determining control content using value functions) As described above, the control content determination unit 102 determines the control content to be applied to the sewage treatment by calculating the values ​​of variables that indicate the control content to be applied to the sewage treatment and the status information 111, so that the amount of nutrients discharged from the sewage treatment facility corresponds to a predetermined target value.

[0048] Specifically, the control content determination unit 102 determines the value of a variable by optimization calculation using a value function 113 that evaluates the value of the variable depending on the degree of deviation between the amount of nutrient salt discharged from the sewage treatment facility, which is represented by the variable indicating the content of control and the state information 111, and a target value. Therefore, the information processing device 1 can determine the optimal value of the variable, and thereby determine appropriate control content. Note that the optimization calculation here means determining the value of the variable (variable indicating the content of control to be applied) that maximizes the value represented by the value function 113.

[0049] The number of the variables may be multiple. When the number of the variables is multiple, the control content determination unit 102 can determine multiple control contents or can determine the control target and the control contents. For example, a variable indicating the device to be controlled and a variable indicating the control amount for the device may be used. In this case, the control content determination unit 102 determines which device is to be the control target and determines the control amount for the device.

[0050] Moreover, it is preferable that the value function 113 includes a term that represents the cost incurred when applying the control contents indicated by the above-mentioned variables. This makes it possible to determine the control contents that are also highly appropriate in terms of cost.

[0051] Depending on whether the cost or the degree of deviation is to be emphasized, the term representing the cost and the term representing the degree of deviation may be weighted separately. For example, in value function 113, the term representing the cost is multiplied by 1 as a weighting value, and the term representing the degree of deviation between the emission amount and the target value is multiplied by 2 as a weighting value, thereby evaluating value with emphasis on the degree of deviation between the emission amount and the target value.

[0052] The value function 113 may be adjusted so that a control that may cause the concentration of nutrients discharged from the sewage treatment facility to exceed the regulated value and a control that may cause the total amount of nutrients discharged in a specified period to exceed the regulated value are evaluated significantly lower. This makes it possible to reliably prevent the concentration of nutrients discharged from the sewage treatment facility and the total amount of nutrients discharged in a specified period from exceeding the regulated value.

[0053] The method of generating the value function 113 is not particularly limited. For example, a value function created by a person may be stored in the storage unit 11 as the value function 113. Also, the number of variables input to the value function may be one or more. For example, a prediction model can be generated that predicts the amount of nutrient discharge from a sewage treatment facility when the control is applied from the variables indicating the content of the control applied to the sewage treatment and the state information 111. Then, by using this prediction model, the difference between the predicted value of the discharge calculated by the prediction model and the target value indicated in the discharge plan information 112 can be calculated. Also, once the content of the control is determined, the cost required for the control (for example, the cost of the chemicals used, electricity charges, labor costs, etc.) is also determined, so that a function that calculates the cost from the variables indicating the content of the control can be created. Therefore, the value function 113 can be created using the above prediction model, the discharge plan information 112, and the function that calculates the cost. Note that since sewage treatment depends on biochemical reactions, a prediction model created once does not always match the current situation well. In such a case, the prediction model may be updated as appropriate.

[0054] Also, for example, an action value function of a DeepQ network that has learned the relationship between certain state information 111, the value of a certain variable indicating the content of control performed at that time, and its value may be stored in the storage unit 11 as the value function 113. In this case, the action value function approximated using a neural network is used as the value function 113.

[0055] The method of optimization calculation applied by the control content determination unit 102 is not particularly limited. In addition, the control content determination unit 102 may exploratoryally determine the optimal variable value. The search method is also not particularly limited, and for example, the control content determination unit 102 may search for the optimal variable value by experimental design (e.g., D-optimal design, etc.) or may search for the optimal variable value by Bayesian optimization. When using the action value function of the DeepQ network, the optimal variable value may be determined by the ε-Greedy method.

[0056] (Processing flow) The flow of processing executed by the information processing device 1 will be described with reference to Fig. 4. Fig. 4 is a flowchart showing an example of processing executed by the information processing device 1. The processing in Fig. 4 is repeatedly executed during a period in which automatic control by the information processing device 1 is applied. The execution cycle of the processing is arbitrary, and may be executed every hour, every other day, or every other month, for example.

[0057] In S11, the data acquisition unit 101 acquires status information 111 indicating the status of sewage treated in the sewage treatment facility. For example, when the process of Fig. 4 is executed every hour, the data acquisition unit 101 acquires status information 111 indicating the status of sewage that has flowed into the sewage treatment facility in the most recent hour. Similarly, when the process of Fig. 4 is executed every other day, the data acquisition unit 101 acquires status information 111 indicating the status of sewage that has flowed into the sewage treatment facility during the day.

[0058] In S12, the control content determination unit 102 determines the content of control to be applied to the treatment of sewage. More specifically, the control content determination unit 102 determines the content of control by calculating the values ​​of variables such that the amount of nutrient discharge from the sewage treatment facility, represented by using variables indicating the content of control and state information 111, corresponds to a predetermined target value indicated in discharge plan information 112. Here, the control content determination unit 102 may determine the content of control by using a value function 113.

[0059] For example, when the process of Fig. 4 is executed every hour, the control content determination unit 102 determines the control content to be applied for one hour until the next execution of the process of Fig. 4. Similarly, when the process of Fig. 4 is executed every other day, the control content determination unit 102 determines the control content to be applied during the day.

[0060] In S13, the facility control unit 103 controls various devices provided in the sewage treatment facility in accordance with the decision made in S12. For example, the facility control unit 103 may notify the control device 2 of the content of the control decided in S12 and cause the control device 2 to perform the control of the content.

[0061] Before performing the process of S13, the control content determination unit 102 may notify the user of the information processing device 1 of the determined control content via the output unit 14 or the communication unit 12. In this case, the process of S13 may be performed only when approval is obtained from the user. Alternatively, the process of S13 may not be performed, and the manager of the sewage treatment facility may control the equipment by referring to the control content determined in S12. In this case, the control content determination unit 102 may notify the user of the control content determined in S12 via the communication unit 12 or the output unit 14.

[0062] The process of FIG. 4 described above includes the control content determination method according to this embodiment. That is, the control content determination method according to this embodiment includes a data acquisition step (S11) of acquiring state information 111 indicating the state of sewage treated in the sewage treatment facility, and a control content determination step (S12) of determining the control content to be applied to the sewage treatment. In the control content determination step, the control content to be applied to the sewage treatment is determined by obtaining the value of a variable that makes the discharge amount of nutrients from the sewage treatment facility, which is expressed using the variable indicating the control content and the state information 111, a value corresponding to a predetermined target value. In addition, the target value is a value determined so that the concentration of nutrients discharged from the sewage treatment facility and the total discharge amount in a predetermined period are equal to or less than the regulation value, and the amount of nutrients is discharged according to the discharge amount requested to the sewage treatment facility. Therefore, according to the control content determination method according to this embodiment, it is possible to discharge the amount of nutrients according to the discharge amount while making the concentration of the nutrients discharged and the total discharge amount in a predetermined period equal to or less than the regulation value.

[0063] [Embodiment 2] The configuration of an information processing device 1A according to this embodiment will be described with reference to Fig. 5. Fig. 5 is a block diagram showing an example of a main configuration of the information processing device 1A. The information processing device 1A differs from the information processing device 1 of the first embodiment in that the control content is determined based on the result of reinforcement learning. Note that in the second embodiment, the same reference numbers are used for the same configuration as in the first embodiment, and the description thereof will not be repeated. The same applies to the third and subsequent embodiments.

[0064] 5, the information processing device 1A includes a control unit 10A that controls each unit of the information processing device 1, and a storage unit 11A that stores various data used by the information processing device 1. The control unit 10A includes a data acquisition unit 101, a control content determination unit 102A, and a facility control unit 103. The storage unit 11A also stores status information 111, discharge plan information 112, and a measure 113A.

[0065] The control content determination unit 102A determines the content of control to be applied to the treatment of sewage in the sewage treatment facility. More specifically, the control content determination unit 102A determines the content of control according to the state indicated in the state information 111 according to a strategy 113A for determining the content of control.

[0066] The policy 113A is generated by a reinforcement learning that gives a reward according to the degree of deviation between the amount of nutrient discharged from the sewage treatment facility after the control and a predetermined target value for a combination of the state of the sewage to be treated and the content of the control performed in that state. For example, the control content determination unit 102A may use, as the policy 113A, a function (i.e., a policy function) that outputs information indicating the content of the control to be performed in the state shown in the state information 111 when each piece of information shown in the state information 111 is input.

[0067] The control content determination unit 102A may determine the control content using a previously generated policy 113A, or may generate or update the policy 113A and determine the control content using the generated or updated policy 113A. That is, the control content determination unit 102A may have a function of generating or updating the policy 113A by reinforcement learning. Note that a control block having a function of generating or updating the policy 113A by reinforcement learning may be provided separately from the control content determination unit 102A.

[0068] As described above, the information processing device 1A includes a data acquisition unit 101 that acquires state information 111 indicating the state of sewage treated in the sewage treatment facility, and a control content determination unit 102A that determines the content of control to be applied to the treatment of sewage. The control content determination unit 102A determines the content of control according to the state indicated in the state information 111 according to a policy 113A generated by reinforcement learning that gives a reward according to the degree of deviation between the amount of nutrient salt discharged from the sewage treatment facility after the control and a predetermined target value for a combination of the state of the sewage to be treated and the content of the control performed in the state. The target value is a value determined so that the concentration of nutrient salt discharged from the sewage treatment facility and the total discharge amount in a predetermined period are equal to or less than the regulation value, and the amount of nutrient salt discharged corresponds to the discharge amount requested to the sewage treatment facility. Therefore, according to the information processing device 1A, it is possible to discharge an amount of nutrient salt according to the discharge amount while keeping the concentration of nutrient salt discharged and the total discharge amount in a predetermined period to or less than the regulation value.

[0069] The reward can be calculated by the value function 113 described in the first embodiment. As described in the first embodiment, the value function 113 may include a term representing the cost incurred when applying the control of the contents indicated by the variables. In other words, the policy 113A may be generated by reinforcement learning that gives a reward according to the cost incurred by performing the control, in addition to the degree of deviation. This makes it possible to determine the control contents that are also appropriate in terms of cost.

[0070] The method of reinforcement learning is not particularly limited. For example, the policy 113A may be generated by Q-learning. In addition, in generating the policy 113A, a DeepQ network that approximates the value function 113 by a deep neural network may be applied. In addition, an algorithm such as Rainbow derived from the DeepQ network may be applied, and the policy 113A may be generated by a method such as a policy gradient method.

[0071] (Processing flow) The flow of the process executed by the information processing device 1A is similar to the flow of the process executed by the information processing device 1 shown in Fig. 4. The difference is that in the information processing device 1A, in S12, the control content determination unit 102A determines the control content by using the policy 113A.

[0072] That is, the control content determination method according to the present embodiment includes a data acquisition step (S11) of acquiring state information indicating the state of sewage treated in the sewage treatment facility, and a control content determination step (S12) of determining the content of control to be applied to the treatment of sewage in the sewage treatment facility. In the control content determination step, the control content according to the state indicated in the state information 111 is determined according to a policy 113A generated by reinforcement learning that gives a reward according to the degree of deviation between the amount of nutrient salt discharged from the sewage treatment facility after the control and a predetermined target value for a combination of the state of the sewage to be treated and the content of the control performed in the state. In addition, the target value is a value determined so that the concentration of nutrient salt discharged from the sewage treatment facility and the total discharge amount in a predetermined period are equal to or less than the regulation value, and the amount of nutrient salt discharged according to the discharge request amount to the sewage treatment facility is equal to or less than the regulation value. Therefore, according to the control content determination method according to the present embodiment, it is possible to discharge an amount of nutrient salt according to the discharge request amount while keeping the concentration of nutrient salt discharged and the total discharge amount in a predetermined period to or less than the regulation value.

[0073] [Embodiment 3] The configuration of an information processing device 1B according to this embodiment will be described with reference to Fig. 6. Fig. 6 is a block diagram showing an example of the configuration of the main parts of the information processing device 1B. The information processing device 1B differs from the information processing device 1 of the first embodiment in that the control content is determined based on the difference between a predicted value of the amount of nutrient salt discharged from a sewage treatment facility and a predetermined target value.

[0074] 6, the information processing device 1B includes a control unit 10B that controls each unit of the information processing device 1B, and a storage unit 11B that stores various data used by the information processing device 1B. The control unit 10B includes a data acquisition unit 101B, a control content determination unit 102B, and a facility control unit 103. The storage unit 11B also stores status information 111B, discharge plan information 112, and a prediction model 113B.

[0075] The data acquisition unit 101B acquires a predicted value of the amount of nutrient salt discharged from the sewage treatment facility. Specifically, the data acquisition unit 101B acquires the predicted value by calculating the predicted value of the amount of nutrient salt discharged according to the state indicated by the state information 111B using the prediction model 113B.

[0076] The status information 111B is information indicating various conditions related to the discharge amount of nutrients. For example, the status information 111B may include information indicating the state of sewage treated in the sewage treatment facility (which may also be called environmental parameters of the inflow water) as well as information indicating the content of the control applied to the treatment of sewage in the sewage treatment facility (which may also be called parameters of the treatment environment).

[0077] The prediction model 113B is a model for calculating a predicted value of the discharge amount of nutrients. The prediction model 113B may be generated by modeling the relationship between parameters indicating various states related to the discharge amount of nutrients and the discharge amount of nutrients when the state is indicated by the parameters. The prediction model 113B may also include a prediction model for the discharge amount of nitrogen and a prediction model for the discharge amount of phosphorus.

[0078] A prediction model for nitrogen emission can be generated, for example, by using water temperature, inflow water volume, and dissolved oxygen concentration as inflow water environmental parameters, and the amount of activated sludge suspended solids in the aerobic tank, the air volume of the blower 3 (i.e., the amount of air blown into the aerobic tank), the amount of liquid delivered by the circulation pump 6 (i.e., the amount of nitrification liquid circulated), and the amount of excess sludge removed by the excess sludge removal pump 5 as treatment environment parameters.

[0079] The environmental parameters of the influent may include the biochemical oxygen demand of the influent, the amount of precipitation in the area where the sewage is discharged, etc. The parameters of the treatment environment may include the amount of organic matter added to promote denitrification, the total nitrogen amount, the dissolved oxygen concentration in the aerobic tank, and the redox potential and pH of the anoxic tank, etc.

[0080] By modeling the relationship between the above parameters and the amount of nutrient salt discharge, a prediction model for nitrogen discharge can be generated. The method for generating the prediction model is not particularly limited, and the prediction model can be generated by, for example, multiple regression analysis, support vector regression, neural network regression, or Gaussian process regression. The prediction model may also be a regression tree model.

[0081] A prediction model for the amount of phosphorus discharged can also be generated in a similar manner. When generating a prediction model for the amount of phosphorus discharged, for example, the water temperature and the amount of inflow water may be used as the environmental parameters of the inflow water, and the amount of chemical added by the chemical addition device 4 may be used as the parameter of the treatment environment. For example, the biochemical oxygen demand, dissolved oxygen concentration, precipitation amount, total phosphorus amount, etc. of the inflow water may also be used as the environmental parameters of the inflow water.

[0082] For each parameter used in generating the prediction model 113B, the latest value is acquired at predetermined time intervals and input to the information processing device 1B via the communication unit 12 or the input unit 13. The input values ​​are stored in the storage unit 11B as status information 111B. This allows the data acquisition unit 101B to extract necessary information from the information included in the status information 111B and input it to the prediction model 113B, thereby making it possible to predict the discharge amount of nutrients from the water treatment facility.

[0083] Since sewage treatment depends on biochemical reactions, it takes time for the control results to be reflected in the entire treatment tank. For this reason, a delay coefficient may be set for each parameter. This allows the data acquisition unit 101B to extract values ​​corresponding to the delay coefficient from the time-series parameters included in the status information 111B and input these values ​​to the prediction model 113B, thereby predicting the discharge amount of nutrients.

[0084] The control content determination unit 102B determines the content of control to be applied to the treatment of sewage in the sewage treatment facility. The control content determination unit 102B differs from the control content determination unit 102 of the first embodiment in that the control content determination unit 102B determines the content of control to be applied to the treatment of sewage in the sewage treatment facility based on the difference between the predicted value acquired by the data acquisition unit 101B and a predetermined target value.

[0085] The above target values ​​are values ​​determined so that the concentration of nutrients discharged from the sewage treatment facility and the total discharge amount in a predetermined period are equal to or less than the regulation value, and so that the amount of nutrients discharged corresponds to the discharge amount requested to the sewage treatment facility, as in the first and second embodiments. The control content determination unit 102B can specify the target value corresponding to the predicted value by referring to the discharge plan information 112.

[0086] For example, when the data acquisition unit 101B acquires a predicted value of the discharge amount of nutrients at time X, one hour after the current time, the control content determination unit 102B identifies a target value at time X from the discharge plan information 112, and calculates information indicating the difference therebetween (for example, difference or ratio). A method of determining the control content based on the difference will be described later.

[0087] The calculation of the predicted value does not necessarily have to be performed by the information processing device 1B, and may be performed by another device. In this case, the data acquisition unit 101B may acquire the predicted value calculated by the other device via the communication unit 12 or the input unit 13.

[0088] Furthermore, the data acquiring unit 101B may acquire an actual value of the amount of nutrients discharged from the sewage treatment facility instead of acquiring a predicted value. The actual value of the amount of nutrients discharged from the sewage treatment facility can be determined by measuring the amount of nutrients contained in the treated water discharged from the sewage treatment facility. The data acquiring unit 101B may acquire such a measured value via the communication unit 12 or the input unit 13.

[0089] When the actual value of the amount of nutrients discharged from the sewage treatment facility is acquired, the control content determination unit 102B determines the content of control to be applied to the treatment of sewage at the sewage treatment facility based on the difference between the acquired actual value and the target value. The method of determining the content of control can be the same as that of determining the content of control based on the difference between the predicted value and the target value.

[0090] The control content determination unit 102B determines the control content so that a predetermined amount of nutrients is discharged at a predetermined time in accordance with the discharge plan information 112. In other words, the control content determination unit 102B determines the control content so that the pattern of the time-series change in the actual discharge amount follows the time-series target value indicated in the discharge plan information 112.

[0091] For example, the control content determination unit 102B may determine the control content for a predetermined period (for example, one day, one month, or one year) based on the discharge plan information 112, and then adjust the control content according to the difference between the actual value and the target value of the discharge amount for each predetermined period. By repeating such adjustment for each predetermined period, the actual value of the discharge amount of nutrients can be made to match the target value indicated in the discharge plan information 112.

[0092] Also, for example, the control content determination unit 102B may adjust the current control content based on the difference between the predicted discharge amount after a certain time, which is predicted from the current control content, and the target value after the certain time. By repeating such adjustment at predetermined time intervals, the actual value of the discharge amount of nutrients can be made to match the target value indicated in the discharge plan information 112.

[0093] As described above, the information processing device 1B includes a data acquisition unit 101B that acquires an actual value of the amount of nutrient discharged from the sewage treatment facility or a predicted value of the amount of the nutrient discharged, and a control content determination unit 102B that determines the content of control to be applied to the treatment of sewage at the sewage treatment facility based on the difference between the actual value or the predicted value and a predetermined target value. The target value is a value that is determined so that the concentration of the nutrient discharged from the sewage treatment facility and the total discharge amount in a predetermined period are equal to or less than the regulation value, and the amount of the nutrient discharged corresponds to the discharge amount requested to the sewage treatment facility. Therefore, according to the information processing device 1B, it is possible to discharge the amount of the nutrient discharged according to the discharge amount while keeping the concentration of the nutrient discharged and the total discharge amount in a predetermined period equal to or less than the regulation value.

[0094] (How control content is determined) For example, the control content determination unit 102B may allocate the difference between the actual value or the predicted value acquired by the data acquisition unit 101B and the target value to a plurality of unit periods into which the target period for adjusting the control content is divided, and determine the control content to be applied in each unit period so as to offset the allocated difference. This makes it possible to make the emission amount match or approach the target value by the control within the target period.

[0095] For example, when the data acquisition unit 101B acquires a predicted value of the discharge amount after a predetermined time, the control content determination unit 102B may divide the predetermined time into a plurality of periods and determine the control content to be applied for each period. As a specific example, assume that the predicted value of the discharge amount of nutrients after 6 hours is "0.6" and the target value of the discharge amount of nutrients after 6 hours is "0.3". In this case, the control content determination unit 102B determines the control content so that the discharge amount of nutrients decreases by 0.05 per hour for the period up to 6 hours. However, when determining the control content so as to increase the discharge amount of nutrients, the control content is determined within a range in which the discharge amount does not exceed the regulation value. The relationship between the control content and the discharge amount of nutrients may be specified and modeled in advance.

[0096] Also, the data acquisition unit 101B may periodically acquire the latest performance value of the amount of nutrient salt discharged from the sewage treatment facility, and the control content determination unit 102B may determine the control content based on the latest performance value. For example, the data acquisition unit 101B may acquire the performance value of the amount of nutrient salt discharged every three days. In this case, the control content determination unit 102B determines the control content for up to three days later based on the acquired performance value (which may be the cumulative value for the most recent three days). Also, for example, if the data acquisition unit 101B acquires the performance value every month, the control content determination unit 102B may determine the control content for up to one month later based on the acquired performance value.

[0097] The actual value used in calculating the difference may be an accumulated value of the actual value in a predetermined period. Similarly, the predicted value may be an accumulated value of the predicted value in a predetermined period. In these cases, the difference between the accumulated value of the target value in the same period is the target of allocation.

[0098] Furthermore, when the cumulative value of the discharge amount of nutrients from the beginning of the year (the first day of the period for which the annual discharge amount is calculated) to a certain point in time is greater than the cumulative value of the target value from the beginning of the year to that point in time, the control content determination unit 102B may determine control content that minimizes the discharge amount of nutrients until the cumulative value of the discharge amount of nutrients becomes equal to or less than the cumulative value of the target value. In this case, the control content determination unit 102B may determine control content such that the discharge amount of nutrients follows the target value after the cumulative value of the discharge amount of nutrients becomes equal to or less than the cumulative value of the target value.

[0099] Alternatively, a simpler method for determining the control contents may be applied. For example, the control contents according to the difference between the emission amount or the predicted value acquired by the data acquisition unit 101B and a predetermined target value may be specified in advance. In this case, the control contents determination unit 102B can determine the control contents according to the emission amount or the predicted value acquired by the data acquisition unit 101B according to the specification.

[0100] For example, it may be specified that when the actual value of the discharge amount is larger than the target value, the amount of the drug added by the drug addition device 4 is increased by a predetermined amount. Furthermore, the amount of the drug added may be increased according to the difference between the actual value of the discharge amount and the target value. In this way, the control content determination unit 102B can determine that when the actual value of the discharge amount is larger than the target value, the drug addition device 4 is controlled to increase the amount of the drug added by a predetermined amount. By executing this control, the amount of nutrient discharge can be reduced. Similarly, when the actual value of the discharge amount is smaller than the target value, it is also possible to control the drug addition device 4 to decrease the amount of the drug added by a predetermined amount. In addition to this, for example, the control content determination unit 102B may adjust the control content by proportional control or PID (Proportional Integral Derivative) control.

[0101] (Determining the timing of control) The control content determination unit 102B may determine at what timing in the target period the adjustment of the control content is to be performed. This will be described with reference to Fig. 7. Fig. 7 is a diagram for explaining the adjustment timing of the control content.

[0102] 7 shows a graph (dashed line) indicating the transition of the target value of the nutrient discharge amount, and a graph (solid line) indicating the transition of the actual value of the nutrient discharge amount. The dashed line graph can be said to represent the discharge plan information 112. The solid line graph can be drawn based on the actual value of the nutrient discharge amount acquired by the data acquisition unit 101B.

[0103] These graphs diverge in period P1. Specifically, the actual value exceeds the target value in period P1. In this case, if control is performed to reduce the nutrient discharge amount in any of periods P2 to P5 after P1, the total annual discharge amount can be made the same as or close to the target amount.

[0104] Here, 702 in FIG. 7 is a graph showing a schematic relationship between the nutrient removal rate and the sewage treatment cost in a sewage treatment facility. As shown in this graph, the higher the nutrient removal rate, the higher the sewage treatment cost. In particular, when the nutrient removal rate is increased further when the nutrient removal rate is high, the rate of increase in treatment cost becomes significantly high. From this graph, it can be seen that when the nutrient removal rate is relatively low, that is, when the amount of nutrient discharge is large, the nutrient removal rate can be increased at a relatively low cost. It can also be seen that when the nutrient removal rate is relatively high, that is, when the amount of nutrient discharge is small, the treatment cost can be significantly reduced by lowering the nutrient removal rate.

[0105] From the above, when the actual value of the discharge amount of nutrients exceeds the target value as in the example of 701 in Fig. 7 and control is performed to reduce the discharge amount of nutrients, the control content decision unit 102B may decide to perform the control in the period P3 to P5 when the target value of the discharge amount of nutrients is relatively large. This makes it possible to execute the control to reduce the discharge amount of nutrients at a cost-effective timing. The period when the target value of the discharge amount of nutrients is relatively large may be determined in advance based on the discharge plan information 112.

[0106] The control content determining unit 102B may determine the above-mentioned period based on the actual amount of nutrient discharge instead of the target amount of nutrient discharge. In this case, the control content determining unit 102B may determine that the control to reduce the amount of nutrient discharge is performed when the actual amount of nutrient discharge reaches or exceeds a predetermined threshold.

[0107] Contrary to the example 701 in Fig. 7, the actual value of the discharge amount of nutrients may fall below the target value, and control to increase the discharge amount of nutrients may be required. In this case, the control content determination unit 102B may determine to perform the control in the period P2, P3, or P5 when the target value of the discharge amount of nutrients is relatively small. This makes it possible to execute control to increase the discharge amount of nutrients at a cost-effective timing. The period when the target value of the discharge amount of nutrients is relatively small may be determined in advance based on the discharge plan information 112.

[0108] The control content determining unit 102B may determine the above-mentioned period based on the actual amount of nutrient discharge instead of the target amount of nutrient discharge. In this case, the control content determining unit 102B may determine that the control to increase the amount of nutrient discharge is performed when the actual amount of nutrient discharge falls below a predetermined threshold.

[0109] As described above, the control content determination unit 102B may determine that the control to increase the discharge amount of nutrients is performed during a period during which the target value is relatively small within the target period for which the control content is adjusted, or when the actual value is equal to or smaller than a predetermined threshold value. A period during which the actual value or the target value of the discharge amount of nutrients is small within the target period is a period during which the cost required to increase the discharge amount of nutrients is small within the target period. Therefore, according to the above configuration, it is possible to execute the control to increase the discharge amount of nutrients at a cost-effective timing.

[0110] It is also assumed that the actual value will not be equal to or less than the predetermined threshold value within the target period. Therefore, when the time until the end of the target period reaches a predetermined lower limit time, the facility control unit 103 may perform the control determined by the control content determination unit 102B even if the actual value is not equal to or less than the threshold value. For example, when controlling the amount of nutrient discharge on a yearly basis, the facility control unit 103 may perform the above control if the actual value is not equal to or less than the threshold value one month before the end of the target period of one year. This also applies to the case of performing control to reduce the amount of nutrient discharge, which will be described below.

[0111] In addition, the control content determination unit 102B may determine that control to reduce the discharge amount of nutrients is to be performed during a period in which the target value is relatively large within the target period for which the control content is adjusted, or when the actual value becomes equal to or greater than a predetermined threshold value.

[0112] A period during which the actual or target value of the nutrient discharge amount is large is a period during which the cost required to reduce the nutrient discharge amount is small. Therefore, according to the above configuration, it is possible to execute control to reduce the nutrient discharge amount at a cost-effective timing.

[0113] The target period may be a long period such as one year, or a short period such as one day. When determining the timing of control execution for a short target period, a period in which the target value is relatively high and a period in which the target value is relatively low may be set in advance. For example, the target value may be set relatively high in the first half of the day, and relatively low in the second half of the day. In this way, the control to reduce the amount of nutrient discharge is performed in the first half of the day, and the control to increase the amount of nutrient discharge is performed in the second half of the day, so that the amount of nutrient discharge can be made to be in line with the target value while suppressing costs.

[0114] Furthermore, the control content determination unit 102B may determine the timing of adjusting the control content, taking into consideration not only the cost but also the requested discharge amount for each season. For example, in the example of 701 in FIG. 7, assume that period P4 is winter and there is a request to increase the amount of nutrient discharge in winter as much as possible. In this case, the control content determination unit 102B may determine that the control to reduce the amount of nutrient discharge is performed in period P3 (preparation period) or period P5 (recovery period) instead of period P4. This makes it possible to reduce the total amount of nutrient discharge per year without reducing the amount of nutrient discharge in winter.

[0115] It is also possible that increasing the amount of nutrient discharge in period P2 (summer) will have a lower contribution to the growth of organisms in the water area than increasing the amount in periods P3 to P5. In this case, the control content determination unit 102B may determine that control to increase the amount of nutrient discharge will be performed in period P3 (preparation period) or period P5 (recovery period) instead of period P2. This makes it possible to increase the contribution to the growth of organisms in the water area compared to increasing the amount of nutrient discharge in period P2, while avoiding period P4, which has the greatest risk of increasing the amount of nutrient discharge.

[0116] (Processing flow) The flow of the process executed by the information processing device 1B will be described with reference to Fig. 8. Fig. 8 is a flowchart showing an example of the process executed by the information processing device 1B. The process of Fig. 8 is repeatedly executed during the period in which automatic control by the information processing device 1B is applied. The execution cycle of the process is arbitrary, and may be executed every hour, every other day, or every other month, for example. Also, S23 is the same process as S13 in Fig. 4, and therefore the description will not be repeated here.

[0117] In S21, the data acquisition unit 101B acquires an actual value of the amount of nutrient discharged from the sewage treatment facility or a predicted value of the amount of nutrient discharged. As described above, the data acquisition unit 101B may calculate a predicted value using the prediction model 113B and the state information 111B, or may acquire an actual value input via the communication unit 12 or the input unit 13.

[0118] For example, when the process of Fig. 8 is performed every other month, the data acquisition unit 101B may acquire the actual value of the amount of nutrient salt discharged from the sewage treatment facility in the most recent month. Also, when the process of Fig. 8 is performed every other hour, the data acquisition unit 101B may input the most recent state information 111B to a prediction model 113B (a model that predicts the amount of nutrient salt discharged one hour later) to calculate a predicted value of the amount of nutrient salt discharged one hour later.

[0119] In S22, the control content determination unit 102B determines the content of control based on the difference between the actual value or predicted value acquired in S21 and a predetermined target value. For example, when the process of Fig. 8 is executed every other month, the control content determination unit 102B may determine the content of control to be applied for one month until the process of Fig. 8 is executed next. Similarly, for example, when the process of Fig. 8 is executed every hour, the control content determination unit 102B may determine the content of control to be applied for one hour.

[0120] As described above, the control content determination unit 102B may also determine the timing to execute the control. When the timing to execute the control is determined, the facility control unit 103 executes the process of S23 at the determined timing.

[0121] The process of FIG. 8 described above includes the control content determination method according to this embodiment. That is, the control content determination method according to this embodiment includes a data acquisition step (S21) of acquiring an actual value of the amount of nutrient discharged from the sewage treatment facility or a predicted value of the amount of the discharge, and a control content determination step (S22) of determining the content of control to be applied to the treatment of sewage at the sewage treatment facility based on the difference between the actual value or the predicted value acquired in S21 and a predetermined target value. The target value is a value determined so that the concentration of the nutrient discharged from the sewage treatment facility and the total discharge amount in a predetermined period are equal to or less than the regulation value, and the amount of nutrient discharged corresponds to the discharge amount requested to the sewage treatment facility. Therefore, according to the control content determination method according to this embodiment, it is possible to discharge the amount of nutrient discharged according to the discharge amount while keeping the concentration of the nutrient discharged and the total discharge amount in a predetermined period equal to or less than the regulation value.

[0122] [Embodiment 4] The configuration of an information processing device 1C according to this embodiment will be described with reference to Fig. 9. Fig. 9 is a block diagram showing an example of the main configuration of the information processing device 1C. The information processing device 1C differs from the information processing device 1B of the third embodiment in that it appropriately corrects a target value of the discharge amount of nutrients and determines control content so that the discharge amount of nutrients approaches the corrected target value.

[0123] 9, the information processing device 1C includes a control unit 10C that controls each unit of the information processing device 1C, and a storage unit 11C that stores various data used by the information processing device 1. The control unit 10C includes a data acquisition unit 101B, a control content determination unit 102C, a facility control unit 103, and a target correction unit 104C. In addition, the storage unit 11C stores state information 111B, discharge plan information 112, and a prediction model 113B.

[0124] The target correction unit 104C corrects the target value after a certain point in time based on the difference between the actual value or predicted value of the amount of nutrient salt discharged from the sewage treatment facility at that point in time and the target value previously set for that point in time. The method of correcting the target value will be described later.

[0125] The control content determination unit 102C determines the content of control to be applied to the treatment of sewage so that the amount of nutrient discharged from the sewage treatment facility approaches the corrected target value. For example, the control content according to the combination of the target value of the discharge amount and the value of the environmental parameter of the inflow water indicated in the status information 111B may be specified in advance. In this case, the control content determination unit 102C can determine the control content according to the status information 111B and the corrected target value in accordance with the specification.

[0126] As described above, the information processing device 1C includes a data acquisition unit 101B that acquires an actual value of the amount of nutrient discharged from the sewage treatment facility at a certain time point or a predicted value of the amount of nutrient discharged, a target correction unit 104C that corrects a target value after the time point based on the difference between the actual value or the predicted value and a target value previously set for the time point, and a control content determination unit 102C that determines the content of control to be applied to the sewage treatment so that the amount of nutrient discharged from the sewage treatment facility approaches the corrected target value. The target value is a value that is determined so that the concentration of the nutrient discharged from the sewage treatment facility and the total discharge amount in a predetermined period are equal to or less than the regulation value, and the amount of nutrient discharged corresponds to the discharge amount requested to the sewage treatment facility. Therefore, according to the information processing device 1C, it is possible to discharge an amount of nutrient salts corresponding to the discharge amount while keeping the concentration of the nutrient salts discharged and the total discharge amount in a predetermined period below the regulation value.

[0127] (How to correct the target value) A method of correcting the target value by the target correction unit 104C will be described with reference to Fig. 10. Fig. 10 is a diagram showing an example of correction of the target value. In Fig. 10, the actual value of the cumulative discharge amount of nutrients per hour in 24 hours from 0:00 to 24:00 is shown by a solid line, and the target value of the cumulative discharge amount of nutrients per hour is shown by a dashed line.

[0128] The target value shown by the dashed line is the value before correction, and increases proportionally with time from 0:00 to 24:00. In other words, the target for this period is to increase the cumulative nutrient discharge amount proportionally with time. This target can be achieved by discharging nutrients at a constant rate.

[0129] However, the actual results shown by the solid line in FIG. 10 deviate slightly from the target values, and at 12:00 the actual results exceed the target values, meaning that the amount of nutrient discharge is too high.

[0130] In this case, the target correction unit 104C may correct the target values ​​for the period after 12:00 to the values ​​shown by the dashed line in Fig. 10. This dashed line is a straight line connecting the actual value at 12:00 and the target value at 24:00. In other words, the target correction unit 104C can determine the equation of the line from the actual value at 12:00 and the target value at 24:00, and set the emission amount at each time represented by the equation as the corrected target value for the period from 12:00 to 24:00.

[0131] The target value may be an accumulated value (a target value of accumulated emissions from the start of the period for which annual emissions are calculated) as in the example of Fig. 10, or may indicate an hourly target value (e.g., an hourly, daily, or monthly target value). For example, in the example of Fig. 10, the slope of the dashed line may be the corrected target value for the period from 12:00 to 24:00 (e.g., the target value of emissions per hour for this period).

[0132] The method of correcting the target value is not limited to the above example. For example, the target correction unit 104C may obtain an equation of a curve connecting the actual value at 12:00 and the target value at 24:00, and set the emission amount at each time represented by the equation as the corrected target value.

[0133] Also, for example, it may be predefined how to correct the target value depending on the difference between the actual or predicted value of the nutrient discharge amount and the target value. In this case, the target correction unit 104C can perform correction according to the actual or predicted value of the discharge amount acquired by the data acquisition unit 101B according to the predefined method.

[0134] For example, it may be specified that when the actual value of the emission amount is larger than the target value, the target value is corrected to a value smaller by a predetermined value. Furthermore, the above-mentioned predetermined value may be specified according to the magnitude of the difference between the actual value of the emission amount and the target value. The period for correction may also be determined in advance. In this way, when the actual value of the emission amount is larger than the target value, the target correction unit 104C corrects the target value to a smaller value, thereby reducing the emission amount. Similarly, it is also possible to correct the target value to a larger value when the actual value of the emission amount is smaller than the target value.

[0135] The target adjustment unit 104C may also adjust the emission amount target value to be larger during a period in which the target value is relatively small within the target period for which the target value is adjusted. Alternatively, the target adjustment unit 104C may adjust the emission amount target value to be larger when the actual value becomes equal to or smaller than a predetermined threshold value.

[0136] As explained based on Figure 7, the period when the target value of nutrient discharge is small is the period during which the cost required to increase nutrient discharge is relatively small within the target period. Therefore, by increasing the target value for this period, it becomes possible to increase nutrient discharge at a time when it is cost-effective.

[0137] In addition, by increasing the target value of the discharge amount when the actual value falls below a predetermined threshold, it is possible to increase the discharge amount of nutrients at a more cost-effective timing. In this case, the target correction unit 104C monitors the actual value of the discharge amount acquired by the data acquisition unit 101B during the target period, and increases the target value of the discharge amount when the actual value falls below a predetermined threshold.

[0138] It is also assumed that the actual value will not be equal to or less than the predetermined threshold value within the target period. Therefore, the target correction unit 104C may correct the target value when the time until the end of the target period reaches a predetermined lower limit time, even if the actual value is not equal to or less than the threshold value. For example, when controlling the discharge amount of nutrients on a yearly basis, the target correction unit 104C may correct the target value if the actual value is not equal to or less than the threshold value one month before the end of the target period of one year. This also applies to the case of correcting the discharge target value to a smaller value, as described below.

[0139] The target adjustment unit 104C may adjust the target value of the emission amount to be smaller during a period in which the target value is relatively large within the target period for which the target value is adjusted. Alternatively, the target adjustment unit 104C may adjust the target value of the emission amount to be smaller when the actual value becomes equal to or larger than a predetermined threshold value.

[0140] As explained based on Figure 7, the period when the target value of nutrient discharge is relatively large is the period during which the cost required to reduce nutrient discharge is relatively small. Therefore, by reducing the target value for this period, it becomes possible to reduce nutrient discharge at a cost-effective time. In addition, by reducing the target value of discharge when the actual value is equal to or greater than a predetermined threshold, it becomes possible to reduce nutrient discharge at a cost-effective time.

[0141] (Processing flow) The flow of the process executed by the information processing device 1C will be described with reference to Fig. 11. Fig. 11 is a flowchart showing an example of the process executed by the information processing device 1C. The process of Fig. 11 is repeatedly executed during the period in which automatic control by the information processing device 1C is applied. The execution cycle of the process is arbitrary, and may be executed every hour, every other day, or every other month, for example. Also, S31 is the same process as S21 in Fig. 8, and S34 is the same process as S13 in Fig. 4, so the description will not be repeated.

[0142] In S32, the target correction unit 104C corrects the target value after the time point based on the difference between the actual value or the predicted value acquired in S31 and the target value preset for the time point. For example, when the process of FIG. 11 is executed every other month, the target correction unit 104C may correct the target value within the period of one month until the process of FIG. 11 is executed next time. Similarly, for example, when the process of FIG. 11 is executed every hour, the target correction unit 104C may correct the target value for the next hour as the target period. Also, as described above, the target correction unit 104C may determine at what timing in the target period the target value is to be corrected.

[0143] In S33, the control content determination unit 102C determines the content of control to be applied to the treatment of the sewage so that the amount of nutrient salt discharged from the sewage treatment facility approaches the corrected target value in S32.

[0144] The process of FIG. 11 described above includes the control content determination method according to this embodiment. That is, the control content determination method according to this embodiment includes a data acquisition step (S31) for acquiring an actual value of the amount of nutrient discharged from the sewage treatment facility at a certain time point or a predicted value of the amount of the discharged amount, a target correction step (S32) for correcting a target value after the time point based on the difference between the actual value or the predicted value acquired in S31 and a target value previously set for the time point, and a control content determination step (S33) for determining the content of control to be applied to the treatment of sewage so that the amount of nutrient discharged from the sewage treatment facility approaches the corrected target value. The target value is a value determined so that the concentration of nutrient discharged from the sewage treatment facility and the total discharge amount in a predetermined period are equal to or less than the regulation value, and the amount of nutrient discharged corresponds to the discharge amount requested to the sewage treatment facility. Therefore, according to the control content determination method according to this embodiment, it is possible to discharge an amount of nutrient salt according to the discharge amount while keeping the concentration of nutrient salt discharged and the total discharge amount in a predetermined period to or less than the regulation value.

[0145] [Modifications] The execution subject of each process described in each of the above-mentioned embodiments is arbitrary and is not limited to the above-mentioned examples. That is, a system having the same functions as the information processing devices 1, 1A, 1B, and 1C can be constructed by a plurality of devices capable of communicating with each other. For example, a system having the same functions as the information processing devices 1, 1A, 1B, and 1C can be constructed by distributing each block shown in FIG. 1, 5, 6, and 9 among a plurality of devices. Also, each process in the flowcharts of FIG. 4, 8, and 11 can be shared and executed by a plurality of information processing devices. That is, the execution subject of the processes in these flowcharts may be one information processing device or may be a plurality of information processing devices.

[0146] [Software implementation example] The functions of the information processing devices 1, 1A, 1B, 1C (hereinafter referred to as "devices") can be realized by a program for causing a computer to function as the device, and a program (control content determination program) for causing a computer to function as each control block of the device (particularly each part included in the control units 10, 10A, 10B, and 10C).

[0147] In this case, the device includes a computer having at least one control device (e.g., a processor) and at least one storage device (e.g., a memory) as hardware for executing the program. The control device and storage device execute the program to realize each function described in each of the above embodiments.

[0148] The program may be non-transitory and may be recorded in one or more computer-readable recording media. The recording media may or may not be included in the device. In the latter case, the program may be provided to the device via any wired or wireless transmission medium.

[0149] In addition, some or all of the functions of each of the control blocks can be realized by a logic circuit. For example, an integrated circuit in which a logic circuit that functions as each of the control blocks is formed is also included in the scope of the present invention. In addition, the functions of each of the control blocks can be realized by, for example, a quantum computer.

[0150] The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the claims. Embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the present invention. [Explanation of symbols]

[0151] 1, 1A, 1B, 1C Information processing device 101, 101B Data acquisition section 102, 102A, 102B, 102C Control content determination unit 104C Target Modification Department 111 Status Information 113 Value Function 113A Measures 2. Control device 9. Control System

Claims

1. a data acquisition unit that acquires status information indicating the status of sewage being treated in the sewage treatment facility; a control content determination unit that determines the content of control to be applied to the sewage treatment, the control content determination unit determines a control content to be applied to the treatment of the sewage by calculating values ​​of the variables that indicate the control content and the state information such that a discharge amount of nutrients from the sewage treatment facility corresponds to a predetermined target value; The target value is a value determined so that the concentration of nutrients discharged from the sewage treatment facility and the total discharge amount in a specified period are below regulated values, and so that an amount of nutrients corresponding to a discharge request amount to the sewage treatment facility is discharged.

2. 2. The information processing device according to claim 1, wherein the control content determination unit determines the value of the variable by an optimization calculation using a value function that evaluates a value of the variable depending on a degree of deviation between an amount of nutrient salt discharged from the sewage treatment facility, the amount being represented using the variable and the state information, and the target value.

3. The information processing device according to claim 2 , wherein the value function includes a term that represents a cost incurred when applying control of the content indicated by the variable.

4. a data acquisition unit that acquires status information indicating the status of sewage being treated in the sewage treatment facility; a control content determination unit that determines the content of control to be applied to the sewage treatment, the control content determination unit determines the content of control according to the state indicated by the state information in accordance with a policy generated by reinforcement learning that gives a reward according to the degree of deviation between the amount of nutrient salt discharged from the sewage treatment facility after the control and a predetermined target value for a combination of the state of the sewage to be treated and the content of the control performed in the state; The target value is a value determined so that the concentration of nutrients discharged from the sewage treatment facility and the total discharge amount in a specified period are below regulated values, and so that an amount of nutrients corresponding to a discharge request amount to the sewage treatment facility is discharged.

5. The information processing device according to claim 4 , wherein the policy is generated by a reinforcement learning method that gives a reward according to a cost incurred by performing control in addition to the degree of deviation.

6. a data acquisition unit that acquires actual values ​​of nutrient discharge amounts from a sewage treatment facility or predicted values ​​of the nutrient discharge amounts; a control content determination unit that determines a content of control to be applied to the treatment of sewage in the sewage treatment facility based on a difference between the actual value or the predicted value and a predetermined target value, The target value is a value determined so that the concentration of nutrients discharged from the sewage treatment facility and the total discharge amount in a specified period are below regulated values, and so that an amount of nutrients corresponding to a discharge request amount to the sewage treatment facility is discharged.

7. 7. The information processing device according to claim 6, wherein the control content determination unit allocates a difference between the actual value or the predicted value and the target value to a plurality of unit periods that divide a target period for adjusting the control content, and determines the control content to be applied in each unit period so as to offset the allocated difference.

8. 8. The information processing device according to claim 6, wherein the control content determination unit determines to perform control to increase the discharge amount of nutrients during a period in which the target value is relatively small within a target period for adjusting the control content, or when the actual value becomes equal to or less than a predetermined threshold value.

9. 8. The information processing device according to claim 6, wherein the control content determination unit determines that the control to reduce the discharge amount of nutrients is performed during a period in which the target value is relatively large within a target period for adjusting the control content, or when the actual value becomes equal to or greater than a predetermined threshold value.

10. A data acquisition unit that acquires an actual value of a nutrient discharge amount from a sewage treatment facility at a certain point in time or a predicted value of the nutrient discharge amount; a target correction unit that corrects a target value after the time point based on a difference between the actual value or the predicted value and a target value that is preset for the time point; and a control content determination unit that determines the content of control to be applied to the treatment of the sewage so that the amount of nutrients discharged from the sewage treatment facility approaches the revised target value; The target value is a value determined so that the concentration of nutrients discharged from the sewage treatment facility and the total discharge amount in a specified period are below regulated values, and so that an amount of nutrients corresponding to a discharge request amount to the sewage treatment facility is discharged.

11. The information processing device according to claim 10 , wherein the target adjustment unit adjusts the emission target value to be larger during a period during which the target value is relatively small within a target period for which the target value is adjusted, or when the actual result value is equal to or smaller than a predetermined threshold value.

12. 12. The information processing device according to claim 10, wherein the target adjustment unit adjusts the emission target value to be smaller during a period in which the target value is relatively large within a target period for which the target value is adjusted, or when the actual result value becomes equal to or greater than a predetermined threshold value.

13. A control content determination method executed by one or more information processing devices, comprising: A data acquisition step of acquiring status information indicating the status of sewage treated in the sewage treatment facility; A control content determination step of determining the content of control to be applied to the treatment of the sewage, In the control content determination step, a control content to be applied to the sewage treatment is determined by calculating a value of the variable that indicates the control content and the state information such that a discharge amount of nutrients from the sewage treatment facility corresponds to a predetermined target value; The control content determination method, wherein the target value is a value determined so that the concentration of nutrients discharged from the sewage treatment facility and the total discharge amount in a specified period are below regulated values, and an amount of nutrients corresponding to a discharge request amount to the sewage treatment facility is discharged.

14. an information processing device that acquires status information indicating a status of sewage being treated in a sewage treatment facility and determines the content of control to be applied to the treatment of the sewage; a control device that controls the treatment of the sewage according to the decision of the information processing device; the information processing device determines a content of control to be applied to the treatment of the sewage by calculating a value of the variable that indicates the content of the control and the state information such that a discharge amount of nutrients from the sewage treatment facility corresponds to a predetermined target value; A control system for a sewage treatment facility, wherein the target value is a value determined so that the concentration of nutrients discharged from the sewage treatment facility and the total discharge amount in a specified period are below regulated values, and so that an amount of nutrients corresponding to a discharge request amount to the sewage treatment facility is discharged.

15. 2. A control content determination program for causing a computer to function as the information processing device according to claim 1, the control content determination program causing a computer to function as the data acquisition unit and the control content determination unit.

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