Information processing device, adjustment method, and adjustment program

Abstract

To properly adjust a state of addition of a medical agent to liquid containing suspended solids.SOLUTION: An information processing device (1) includes: a water content predication unit (102) which calculates a first prediction value of a water content of a dehydrated cake by using first measured data relating to properties and states of liquid before a state of addition of a medical agent is changed and calculates a second prediction value of the water content by using second measured data measured after the state of addition of the medical agent is changed; and an adjustment unit (103) which adjusts the state of addition of the medical agent on the basis of the first prediction value and the second prediction value.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an information processing device or the like that performs a process related to the addition of a chemical agent in a process of dehydrating a liquid containing suspended solids by adding a chemical agent that aggregates the suspended solids and then dehydrating with a dehydrator.

Background Art

[0002] The sludge treatment carried out in wastewater treatment facilities such as sewage treatment plants includes a step of dehydrating sludge with a dehydrator. For efficient sludge treatment, it is important to maintain the moisture content of the dehydrated cake obtained by dehydration within a predetermined range. However, when dehydration is performed with the operating conditions of the dehydrator fixed, it is not easy to maintain the moisture content of the dehydrated cake within a predetermined range because the moisture content of the dehydrated cake fluctuates due to reasons such as the properties of the supplied sludge not being constant.

[0003] For this reason, the development of a technique for predicting the moisture content of the dehydrated cake has been conventionally advanced. If the moisture content can be predicted, it becomes possible to maintain the moisture content within a predetermined range by feedforward control. For example, Patent Document 1 below discloses a technique for generating a moisture content estimation model using a plurality of parameters such as the amount of sludge supplied to a centrifugal dehydrator and values related to the centrifugal effect of the dehydrator, and estimating the moisture content.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] Since there is a correlation between the rate at which chemicals are added to the sludge (also called the chemical injection rate) and the predicted moisture content of the dewatered cake, the chemical injection rate can be adjusted using the predicted moisture content. In other words, since increasing the chemical injection rate usually lowers the moisture content, the chemical injection rate should be increased until the predicted moisture content falls within the desired range.

[0006] However, if the chemical injection rate is excessive, the moisture content may not decrease, or it may even increase. Therefore, adjusting the chemical injection rate until the predicted moisture content falls within the desired range may result in the wasteful addition of excessive chemicals. This problem is not limited to sludge, but is a common issue in the dewatering treatment of any liquid containing suspended solids, where chemicals are added to coagulate suspended solids before dewatering.

[0007] One aspect of the present invention aims to realize an information processing device, etc., that can appropriately adjust the manner in which a drug that causes suspended solids to flocce is added to a liquid containing said suspended solids. [Means for solving the problem]

[0008] To solve the above problems, an information processing device according to one aspect of the present invention predicts the water content of a dewatered cake obtained by adding a chemical agent to a liquid containing suspended solids and then dewatering it using a dewatering machine, and includes a water content prediction unit that calculates a first predicted value using first measurement data related to the properties of the liquid before the manner of adding the chemical agent is changed, and a second predicted value using second measurement data related to the properties of the liquid after the manner of adding the chemical agent is changed, and an adjustment unit that adjusts the manner of adding the chemical agent based on the first predicted value and the second predicted value.

[0009] Furthermore, an adjustment method according to one aspect of the present invention is a method for adjusting the manner in which a drug is added, which is performed by one or more information processing devices, in order to solve the above problems, and includes the steps of predicting the water content of a dewatered cake obtained by adding a drug that aggregates suspended solids to a liquid containing suspended solids and then dewatering it with a dewatering machine, and the steps of calculating a first predicted value using first measurement data related to the properties of the liquid before the manner in which the drug is added is changed, calculating a second predicted value of the water content of the dewatered cake using second measurement data related to the properties of the liquid after the manner in which the drug is added is changed, and adjusting the manner in which the drug is added based on the first predicted value and the second predicted value. [Effects of the Invention]

[0010] According to one aspect of the present invention, it becomes possible to appropriately adjust the manner in which a drug that causes suspended solids to flocce is added to a liquid containing suspended solids. [Brief explanation of the drawing]

[0011] [Figure 1] This is a block diagram showing an example of the main components of an information processing device according to one embodiment of the present invention. [Figure 2] This figure shows an example configuration of a control system including the above-mentioned information processing device. [Figure 3] This figure shows examples of adjustments to the method of adding the drug. [Figure 4] This figure shows other examples of adjustments in the manner of adding the drug. [Figure 5] This figure shows further examples of adjustments to the method of adding the drug. [Figure 6] This flowchart shows an example of the process performed by the above-mentioned information processing device. [Figure 7] This flowchart shows an example of a process for determining the effectiveness of reducing the drug injection rate. [Figure 8] This flowchart shows an example of a process for determining the effect of increasing the drug injection rate. [Modes for carrying out the invention]

[0012] [System Configuration] The configuration of a control system according to one embodiment of the present invention will be described based on Figure 2. Figure 2 is a diagram showing an example of the configuration of the control system 100. The control system 100 is a system used in a plant that adds an agent to coagulate solid suspended matter to the liquid to be treated (liquid) in a coagulation tank to form flocs, and then performs solid-liquid separation of the liquid to be treated in which the flocs have been formed. In the following, an example in which the liquid to be treated is sludge will be described, but the control system 100 can also be applied to plants that treat liquids other than sludge. Sludge is a liquid containing fine solid matter generated in wastewater treatment, etc., and can also be called slurry.

[0013] As will be explained in detail below, the control system 100 performs each step of the sludge treatment process, from the step of agglomerating the solid suspended matter in the sludge to be treated to form flocs, thereby converting the sludge to be treated into agglomerated sludge, to the step of dewatering the agglomerated sludge to obtain dewatered sludge (also called dewatered cake) and dewatered filtrate. As shown in Figure 2, the control system 100 includes an information processing device 1, a control device 3, a flocculator 5, and a dewatering machine 9.

[0014] The flocculator 5 is a device that forms flocs by adding a chemical agent that coagulates solid suspended matter to the liquid to be treated in the coagulation tank and stirring it appropriately. Specifically, the flocculator 5 uses sludge as the liquid to be treated, coagulates the solid suspended matter in the sludge to form flocs, and produces coagulated sludge. The flocculator 5 in Figure 2 is equipped with a coagulation tank 51, a stirring blade 52, a motor 53, and an inspection window 54. The flocculator 5 is also provided with a sludge inlet 55, a chemical agent inlet 56, and a discharge port 57.

[0015] Furthermore, a photographing device 72 and a lighting device 71 for photographing are attached to the inspection window 54. The photographing device 72 only needs to be able to photograph at least still images. During the operation of the control system 100, it is preferable that the flocculation tank 51 has no light transmittance so that the way light hits the flocs does not change. Also, the photographing device 72 and the lighting device 71 are preferably housed in a light-shielding dark box with an opening on the inspection window 54 side, as in the illustrated example.

[0016] The dehydrator 9 is a device for performing solid-liquid separation of the liquid to be treated in which flocs are formed. Specifically, the dehydrator 9 is disposed downstream of the flocculator 5 and dehydrates the flocculated sludge discharged from the flocculator 5 to perform solid-liquid separation. The dehydrator 9 in FIG. 2 is a screw press type dehydrator including an outer cylinder screen 91 and a screw 92. The dehydrator 9 is also provided with a sludge inlet 93, a filtrate outlet 94, and a dewatered cake outlet 95. Although not shown, the dehydrator 9 also includes a motor or the like for rotationally driving the screw 92. Of course, the dehydrator 9 only needs to be able to dehydrate the flocculated sludge and is not limited to the screw press type. For example, a centrifugal dehydrator, a filter press type dehydrator, or a belt press dehydrator can also be applied.

[0017] In the control system 100, the sludge to be treated is continuously or intermittently supplied from the sludge inlet 55 into the flocculation tank 51 of the flocculator 5 by a supply device (not shown), and the sludge pushed out and discharged from the flocculation tank 51 is supplied to the dehydrator 9. Therefore, the flow rate of the sludge supplied to the flocculation tank 51 and the flow rate of the sludge supplied to the dehydrator 9 coincide at the same time. The supply speed of the sludge may be automatically controlled by the supply device or its control device 3 according to the sludge treatment speed by the flocculator 5 and the dehydrator 9.

[0018] Then, a chemical (including at least a flocculant) for flocculating the sludge in the flocculation tank 51 is introduced from the chemical inlet 56. In this state, the motor 53 is driven to rotate the stirring blade 52, stirring the sludge and the chemical to form flocs. The flocculated sludge, which is a mixture of the formed flocs and the water contained in the sludge, is discharged from the discharge port 57.

[0019] Subsequently, this flocculated sludge is supplied into the outer cylinder screen 91 from the sludge inlet 93 of the dehydrator 9. Inside the dehydrator 9, the above flocculated sludge is dehydrated under pressure by the screw 92, the filtrate is discharged from the filtrate discharge port 94, and the dehydrated cake, which is a solid mass of the dehydrated flocculated sludge, is discharged from the dehydrated cake discharge port 95.

[0020] Although details will be described below, the information processing device 1 predicts the moisture content of the dehydrated cake obtained by adding a chemical for flocculating the suspended solids to a liquid containing suspended solids and then dehydrating it with the dehydrator 9. Note that the liquid containing suspended solids may be, for example, the sludge described above.

[0021] More specifically, the information processing device 1 calculates a first predicted value using first measurement data related to the properties of the liquid after the addition of the chemical and before the mode of addition of the chemical is changed, and calculates a second predicted value using second measurement data related to the properties of the liquid after the mode of addition of the chemical is changed. Then, the information processing device 1 adjusts the mode of addition of the chemical based on the calculated first predicted value and second predicted value.

[0022] Changing the mode of addition of the chemical affects the properties of the liquid to which the chemical is added. And the change in the properties of the liquid brings about a change in the measurement data, which affects the predicted value of the moisture content using that measurement data. Therefore, the above-described first predicted value and second predicted value serve as indices for evaluating the effects brought about by the change in the mode of addition of the chemical. Thus, according to the above configuration, it becomes possible to appropriately adjust the mode of addition of the chemical in consideration of the effects brought about by the change in the mode of addition of the chemical.

[0023] Furthermore, the information processing device 1 can also control the operation of various devices that are components of the control system 100 (for example, the flocculator 5, the dewatering machine 9, and a chemical supply device not shown) via the control device 3. The control device 3 is a device that controls the operation of various devices that are components of the control system 100. The control device 3 may be, for example, a PLC (Programmable Logic Controller).

[0024] [Device configuration] The configuration of the information processing device 1 will be explained based on Figure 1. Figure 1 is a block diagram showing an example of the main components of the information processing device 1. As shown in the figure, the information processing device 1 includes a control unit 10 that controls all parts of the information processing device 1, 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 for the information processing device 1 to communicate with other devices, an input unit 13 that receives input of various data to the information processing device 1, and an output unit 14 for the information processing device 1 to output various data. The control unit 10 also includes a data acquisition unit 101, a moisture content prediction unit 102, and an adjustment unit 103.

[0025] The data acquisition unit 101 acquires various data necessary for predicting the water content. Specifically, the data acquisition unit 101 acquires first measurement data related to the properties of the liquid after the drug has been added but before the method of drug addition is changed, and second measurement data related to the properties of the liquid after the method of drug addition is changed. The first and second measurement data will be explained with specific examples in the section "About Measurement Data" below.

[0026] The moisture content prediction unit 102 predicts the moisture content of a dewatered cake obtained by adding a chemical agent that coagulates suspended solids to a liquid containing suspended solids and then dewatering it using a dewatering machine. More specifically, the moisture content prediction unit 102 calculates a first predicted value using first measurement data related to the properties of the liquid before the method of adding the chemical agent is changed, and calculates a second predicted value using second measurement data related to the properties of the liquid after the method of adding the chemical agent is changed. The moisture content prediction method will be explained later in the section "Moisture Content Prediction Method".

[0027] The adjustment unit 103 adjusts the method of adding the drug based on the first predicted value and the second predicted value predicted by the moisture content prediction unit 102. The method for adjusting the method of adding the drug will be explained later in the section "Method for adjusting the method of adding the drug".

[0028] As described above, the information processing device 1 according to this embodiment predicts the moisture content of a dewatered cake obtained by adding a chemical agent to a liquid containing suspended solids and then dewatering it using a dewatering machine. It includes a moisture content prediction unit 102 that calculates a first predicted value using first measurement data related to the properties of the liquid before the manner of chemical addition is changed, and a second predicted value using second measurement data related to the properties of the liquid after the manner of chemical addition is changed, and an adjustment unit 103 that adjusts the manner of chemical addition based on the first predicted value and the second predicted value. This makes it possible to appropriately adjust the manner in which a chemical agent that coagulates suspended solids is added to a liquid containing suspended solids.

[0029] [Regarding measurement data] The first measurement data relates to the properties of the liquid after the drug has been added but before the method of drug addition has been changed. The first predicted value, which is a predicted value of the water content, is calculated using the first measurement data. The second measurement data relates to the properties of the liquid after the method of drug addition has been changed. The second predicted value, which is a predicted value of the water content, is calculated using the second measurement data. The second measurement data used is taken after sufficient time (e.g., 5 minutes or more) has elapsed since the method of drug addition was changed for the effect to appear in the measurement data.

[0030] Thus, although the first and second measurement data are measured at different times, they are both used to calculate predicted moisture content values, and while the values ​​may differ, the data type is the same. For this reason, in this section, unless otherwise specified, the first and second measurement data will simply be referred to as "measurement data."

[0031] The measurement data only needs to be relevant to the properties of the liquid after the drug has been added. For example, data indicating the properties of the liquid may be used as measurement data. For example, data indicating the size of the flocs in the flocculator 5 may be used as measurement data.

[0032] Furthermore, changes in the properties of the liquid before and after a change in the method of adding the chemical agent also result in changes in the measurement data measured by the various equipment that processes the liquid. For example, when the properties of the liquid change, the operating state of the dewatering machine 9, which dewaters the liquid while transporting it, may also change. For this reason, the data measured by the various equipment that processes the liquid may also be used as measurement data.

[0033] For example, when performing control to keep the pressure constant when supplying liquid to the dewatering machine 9 (or flocculator 5) (hereinafter referred to as constant pressure control), data indicating the flow rate of liquid supplied to the dewatering machine 9 per unit time may be used as measurement data.

[0034] Here, let's assume that when constant pressure control is performed, the drug injection rate (the ratio of the amount of drug to the amount of liquid) at a certain point in time is lower than the appropriate range. If the drug injection rate is increased in this state, the filtration rate of the liquid in the dewatering machine 9 after drug addition will increase. Therefore, due to constant pressure control, the liquid supply flow rate will increase by an amount equivalent to the increase in filtration rate. And, as the supply flow rate increases, the predicted value of the moisture content of the dewatered cake will decrease.

[0035] Therefore, in this example, the moisture content predicted from the supply flow rate after increasing the drug injection rate (second prediction) is lower than the moisture content predicted from the supply flow rate before increasing the drug injection rate (first prediction). In other words, in this example, the second prediction is smaller than the first prediction, which means that the change in the method of drug addition, which is increasing the drug injection rate, has the effect of lowering the moisture content.

[0036] This makes it possible to make appropriate adjustments, such as increasing the drug injection rate, based on the fact that the second predicted value is smaller than the first predicted value when the moisture content should be reduced. Thus, data indicating the flow rate of liquid supplied per unit time to the dewatering machine 9 is suitable as measurement data. The same applies to other measurement data related to the operation of the dewatering machine 9, which dewaters while transporting the liquid inside the machine. Of course, the measurement data can be any data related to the properties of the liquid after the addition of the drug, and is not limited to the example above. In any case, the second measurement data should be taken after sufficient time has elapsed since the change in the method of drug addition so that the effect appears in the measurement data.

[0037] [Method for predicting moisture content] The moisture content prediction unit 102 calculates a predicted moisture content using the measurement data (first measurement data and second measurement data) acquired by the data acquisition unit 101 as described above. For predicting moisture content, for example, a moisture content prediction model can be used.

[0038] A moisture content prediction model models the relationship between measurement data as the explanatory variable and moisture content as the dependent variable. For example, a prediction model generated by machine learning using training data that shows the correspondence between previously measured measurement data and the corresponding moisture content can be used. The algorithm of the prediction model is not particularly limited; for example, regression or multiple regression models, neural networks, or random forests can be used.

[0039] Furthermore, the explanatory variables in the predictive model must include data related to the properties of the liquid at the time of drug addition. However, the explanatory variables in the predictive model only need to be data related to water content, and these explanatory variables may include data that is not particularly related to or is considered unrelated to the properties of the liquid at the time of drug addition.

[0040] For example, the explanatory variables of the predictive model may include at least one of the following: data indicating the concentration of suspended solids in the liquid supplied to the dewatering machine 9; data regarding the chemical supplied to the flocculator 5 (chemical supply flow rate, ratio of the amount of chemical to the amount of liquid i.e., chemical injection rate, etc.); data regarding the liquid in the flocculator 5 (floc size or various related indicator values); data indicating the operating conditions of the flocculator 5 (stirring speed, etc.); and data indicating the operating conditions of the dewatering machine 9 (screw rotation speed, operating time, input pressure, etc.). Note that the indicator values ​​regarding the liquid in the flocculator 5 may be obtained, for example, by analyzing images taken with the imaging device 72 shown in Figure 2.

[0041] [Methods for adjusting the manner in which drugs are added] The adjustment unit 103 adjusts the method of adding the drug based on the first and second predicted values ​​predicted by the moisture content prediction unit 102. The method of adding the drug refers to how the drug is added. For example, changing or adjusting at least one of the drug injection rate, the amount of drug added, and the drug supply flow rate constitutes changing or adjusting the method of adding the drug. In addition, changing the type or formulation of the drug to be added also constitutes changing the method of adding the drug.

[0042] The following describes an example of adjusting the drug injection rate. The adjustment unit 103 can adjust the drug injection rate (specifically, increase or decrease the drug injection rate) by directly controlling the supply device that supplies the drug to the flocculator 5, or by controlling it via other devices such as the control device 3. The same applies when adjusting the amount of drug added or the supply flow rate.

[0043] For example, the adjustment unit 103 may determine the effect of the adjustment to reduce the drug injection rate based on a first predicted value calculated using first measurement data measured before reducing the drug injection rate and a second predicted value calculated using second measurement data measured after reducing the drug injection rate. Hereinafter, this determination will be referred to as the drug injection rate reduction effect determination. The adjustment unit 103 may then adjust the manner of drug addition according to the result of the drug injection rate reduction effect determination.

[0044] Similarly, the adjustment unit 103 may determine the effect of the adjustment to reduce the drug injection rate based on a first predicted value calculated using first measurement data measured before the drug injection rate is increased, and a second predicted value calculated using second measurement data measured after the drug injection rate is reduced. Hereinafter, this determination will be referred to as the drug injection rate reduction effect determination. The adjustment unit 103 may then adjust the manner of drug addition according to the result of the drug injection rate reduction effect determination.

[0045] (1: Basic adjustment methods) The following section explains how to determine the effect of reducing and increasing the drug injection rate based on Figure 3. Figure 3 is a diagram showing an example of adjusting the manner in which the drug is added. Figure 3 also shows a graph showing the relationship between the drug injection rate and the predicted water content. As shown in this graph, the predicted water content generally decreases as the drug injection rate increases, but once the drug injection rate reaches a certain level, the predicted water content will not decrease further even if the drug injection rate is increased further, and in some cases, the predicted water content may even increase if the drug injection rate is increased even more.

[0046] (1-1: Evaluation of the effect of reducing the drug injection rate) EX1, shown in Figure 3, is an example of adjusting the drug injection rate based on the results of the drug injection rate reduction effect assessment. In this adjustment example, the drug injection rate reduction effect assessment is performed after making an adjustment to reduce the drug injection rate. Then, the drug injection rate is reduced when the result of the drug injection rate reduction effect assessment is "predicted water content decreases" or "predicted water content remains unchanged," and this process is repeated until the result of the drug injection rate reduction effect assessment is "predicted water content increases." The drug injection rate is then adjusted to the value just before the result of the drug injection rate reduction effect assessment was "predicted water content increases."

[0047] The effectiveness of reducing the drug injection rate is determined based on the relationship between the predicted moisture content (first predicted value and second predicted value) calculated using the measurement data (first measurement data and second measurement data) before and after making adjustments to reduce the drug injection rate. In other words, if the second predicted value is smaller than the first predicted value, it means that the "predicted moisture content has decreased"; if the first and second predicted values ​​are equal, it means that the "predicted moisture content remains unchanged"; and if the second predicted value is larger than the first predicted value, it means that the "predicted moisture content has increased."

[0048] Furthermore, the adjustment unit 103 may determine that "the predicted water content remains unchanged" if the difference between the first predicted value and the second predicted value is below a threshold. This reduces the possibility that the results of the drug injection rate reduction effect assessment may vary due to the influence of prediction errors, etc.

[0049] The following provides a detailed explanation. In EX1, the initial state before adjustment by the adjustment unit 103 is shown by point P11 on the graph. When adjusting the drug injection rate based on the results of the drug injection rate reduction effect evaluation, it is preferable to set the drug injection rate higher in the initial state.

[0050] In determining the effectiveness of reducing the drug injection rate, the data acquisition unit 101 acquires first measurement data measured in the initial state, and the moisture content prediction unit 102 calculates a first predicted value using the first data.

[0051] Next, the adjustment unit 103 reduces the drug injection rate. The state after the drug injection rate reduction is shown at point P12. In the state at point P12, the data acquisition unit 101 acquires second measurement data, and the moisture content prediction unit 102 calculates a second predicted value using the second measurement data. In EX1, the predicted moisture content decreases when transitioning from the state at point P11 to the state at point P12. Therefore, the result of the drug injection rate reduction effect judgment is "predicted moisture content decreases".

[0052] Therefore, the adjustment unit 103 further reduces the drug injection rate. Point P13 shows the state after the drug injection rate has been further reduced. In the state at point P13, the data acquisition unit 101 acquires measurement data, and the moisture content prediction unit 102 calculates a predicted value using the acquired measurement data. In EX1, since the predicted moisture content does not change when transitioning from the state at point P12 to the state at point P13, the result of the drug injection rate reduction effect judgment for the adjustment made at point P12 is "predicted moisture content remains unchanged".

[0053] Therefore, the adjustment unit 103 further reduces the drug injection rate. In Figure 3, point P14 shows the state after further reduction of the drug injection rate. In the state at point P14, the data acquisition unit 101 acquires measurement data, and the moisture content prediction unit 102 calculates a predicted value using the acquired measurement data. In EX1, since the predicted moisture content increases when transitioning from the state at point P13 to the state at point P14, the result of the drug injection rate reduction effect judgment for the adjustment made at point P13 is "predicted moisture content increases". For this reason, the adjustment unit 103 increases the drug injection rate from the state at point P14 back to the drug injection rate at point P13. As a result, the drug injection rate is adjusted to the value at which the moisture content is expected to be lowest.

[0054] Furthermore, when adjusting the drug injection rate based on the results of the drug injection rate reduction effect assessment, the adjustment unit 103 may terminate the adjustment when the result of the drug injection rate reduction effect assessment becomes "the predicted value of water content remains unchanged." In this case as well, the final adjustment will be to the state shown at point P13 in Figure 3. Alternatively, the adjustment unit 103 may increase the drug injection rate when the result of the drug injection rate reduction effect assessment becomes "the predicted value of water content remains unchanged," and adjust it to the drug injection rate at which the final result of the drug injection rate reduction effect assessment became "the predicted value of water content decreases." In this case, the final adjustment will be to the state shown at point P12.

[0055] (1-2: Evaluation of the effect of increasing the drug injection rate) EX2, shown in Figure 3, is an example of adjusting the drug injection rate based on the results of the drug injection rate increase effect evaluation. In this adjustment example, the drug injection rate increase effect evaluation is performed after making an adjustment to increase the drug injection rate. Then, the drug injection rate is increased when the result of the drug injection rate increase effect evaluation is "predicted water content decreases," and this process is repeated until the result of the drug injection rate increase effect evaluation is "predicted water content increases" or "predicted water content remains unchanged." The drug injection rate is then adjusted to the value just before the result of the drug injection rate increase effect evaluation is "predicted water content increases" or "predicted water content remains unchanged."

[0056] In evaluating the effect of increasing the drug injection rate, similar to evaluating the effect of decreasing the drug injection rate, if the second predicted value is smaller than the first predicted value, it means that "the predicted water content has decreased." If the first and second predicted values ​​are equal, it means that "the predicted water content remains unchanged." If the second predicted value is larger than the first predicted value, it means that "the predicted water content has increased." As mentioned above, if the difference between the first and second predicted values ​​is below a threshold, it may be considered that "the predicted water content remains unchanged."

[0057] In EX2, point P21 shows the initial state before adjustment by the adjustment unit 103, and points P22 to P25 show the state after the first to fourth increases in the drug injection rate, respectively. When adjusting the drug injection rate based on the results of the drug injection rate increase effect evaluation, it is preferable to set the initial drug injection rate low.

[0058] In this example, the predicted moisture content increases when the state transitions from point P24 to point P25 after the third increase in the drug injection rate. Therefore, the result of the drug injection rate increase effect assessment for the adjustment made at point P24 is "predicted moisture content increased." For this reason, the adjustment unit 103 reduces the drug injection rate from the state at point P25 to return to the state at point P24. As a result, the drug injection rate is adjusted to the value at which the moisture content is expected to be lowest.

[0059] Furthermore, when adjusting the drug injection rate based on the results of the drug injection rate increase effect assessment, the adjustment unit 103 may terminate the adjustment when the result of the drug injection rate increase effect assessment becomes "the predicted value of water content remains unchanged." Alternatively, the adjustment unit 103 may decrease the drug injection rate when the result of the drug injection rate increase effect assessment becomes "the predicted value of water content remains unchanged," and adjust it to the drug injection rate at which the result of the drug injection rate reduction effect assessment last became "the predicted value of water content decreases."

[0060] (2: Adjustment method to restore drug injection rate) When evaluating the effectiveness of reducing or increasing the drug injection rate, the drug injection rate is increased or decreased as described above. However, it is also possible to return the drug injection rate to its original value before evaluating the effectiveness of reducing or increasing the drug injection rate. This will be explained with reference to Figures 4 and 5.

[0061] Figure 4 shows another example of adjustment in the manner of drug addition. In EX3 shown in Figure 4, the initial state is indicated by point P31. The data acquisition unit 101 acquires the first measurement data measured in the state shown at point P31, and the moisture content prediction unit 102 calculates a first predicted value using this first data. After this, the adjustment unit 103 reduces the drug injection rate and the state transitions to point P32. In the state at point P32, the data acquisition unit 101 acquires the second measurement data, and the moisture content prediction unit 102 calculates a second predicted value using the second measurement data. Up to this point, the process is the same as the transition from point P11 to point P12 in EX1 shown in Figure 3.

[0062] In EX3, at point P32, the adjustment unit 103 performs a process to return the drug injection rate to its pre-reduction state. Then, at point P31', where the drug injection rate has returned to its pre-reduction state, the data acquisition unit 101 acquires measurement data again (third measurement data), and the moisture content prediction unit 102 calculates a third predicted value using the third measurement data. Note that the data acquisition unit 101 acquires the third measurement data after sufficient time has elapsed since the drug injection rate was returned, so that the effect appears in the measurement data.

[0063] Thus, in the EX3 adjustment example, a total of three measurement data points (the first to third measurement data points) are acquired: the state of point P31 before the drug injection rate is changed, the state of point P32 after the change, and the state of point P31' when it is returned to its pre-change state. Three predicted values ​​(the first to third predicted values) are calculated using these measurement data points. In this case, the adjustment unit 103 uses the first to third predicted values ​​to determine the drug injection rate reduction effect.

[0064] For example, the adjustment unit 103 may compare the average of the third predicted value and the first predicted value with the second predicted value, and if the second predicted value is smaller than the average, it may determine that "the predicted moisture content has decreased"; if the average and the second predicted value are equal, it may determine that "the predicted moisture content has not changed"; and if the second predicted value is larger than the average, it may determine that "the predicted moisture content has increased".

[0065] Furthermore, the adjustment unit 103 may determine that "the predicted moisture content remains unchanged" if the difference between the average value and the second predicted value is less than or equal to a threshold. When this threshold is ΔW and the first to third predicted values ​​are W1 to W3 respectively, the adjustment unit 103 may determine that "the predicted moisture content has decreased" when condition (1) below is satisfied, determine that "the predicted moisture content remains unchanged" when condition (2) below is satisfied, and determine that "the predicted moisture content has increased" when condition (3) below is satisfied. W2 - (W1 + W3) / 2 < - ΔW …(1) -ΔW≦W2-(W1+W3) / 2<ΔW …(2) ΔW≦W2-(W1+W3) / 2 …(3) In EX3, the predicted moisture content at point P32 is lower than that at points P31 and P31'. Therefore, the result of the drug injection rate reduction effect assessment is "predicted moisture content has decreased". In this case, as shown in the figure, the adjustment unit 103 further reduces the drug injection rate and transitions to the state at point P32.

[0066] After this, the same process is repeated as in EX1 until the result of the drug injection rate reduction effect judgment becomes "the predicted value of moisture content increases". Specifically, first, the adjustment unit 103 reduces the drug injection rate from the state at point P32 to the state at point P33, as shown in the figure, and then returns to the drug injection rate at point P32. Then, the drug injection rate reduction effect judgment is performed in the state where the drug injection rate has been returned to its original value (the state shown at point P32'). This process is repeated until the drug injection rate is adjusted to the value just before the result of the drug injection rate reduction effect judgment becomes "the predicted value of moisture content increases".

[0067] On the other hand, in EX4, the initial state is shown at point P41. Furthermore, the state transitioned by reducing the drug injection rate from the state at point P41 is shown at point P42, and the state returned to the drug injection rate of point P41 is shown at point P41'. As shown in the figure, the predicted moisture content in the state at point P42 is larger than in the states at points P41 and P41', so the result of the drug injection rate reduction effect assessment for the treatment at point P41 is "predicted moisture content increased".

[0068] In this case, as shown in the figure, the adjustment unit 103 increases the drug injection rate from the state at point P41' to the state at point P43, and then returns to the drug injection rate at point P41'. The returned state is indicated by point P41''. After this, similar to EX2, the process is repeated until the result of the drug injection rate increase effect judgment is either "the predicted value of water content increases" or "the predicted value of water content remains unchanged," and the drug injection rate is adjusted to the value just before the result of the drug injection rate increase effect judgment is either "the predicted value of water content increases" or "the predicted value of water content remains unchanged." The drug injection rate increase effect judgment when returning to the original state will be explained based on Figure 5.

[0069] Thus, the adjustment unit 103 may first reduce the drug injection rate to determine the effect of reducing the drug injection rate, and if the result of the drug injection rate reduction effect determination is "the predicted value of water content increases", it may switch to adjusting in the direction of increasing the drug injection rate. In this case, it is not necessary to set the drug injection rate high or low in the initial state. This is also the same in the case where the drug injection rate is not restored (see Figure 3).

[0070] Figure 5 shows another example of adjustment to the method of adding the drug. The initial state of EX5 shown in Figure 5 is indicated by point P51. The data acquisition unit 101 acquires the first measurement data measured in the state shown at point P51, and the moisture content prediction unit 102 calculates a first predicted value using the first data. After this, the adjustment unit 103 increases the drug injection rate and transitions to the state at point P52. In the state at point P52, the data acquisition unit 101 acquires the second measurement data, and the moisture content prediction unit 102 calculates a second predicted value using the second measurement data. Up to this point, the process is the same as the transition from point P21 to point P22 in EX2 shown in Figure 3.

[0071] In EX5, at point P52, the adjustment unit 103 performs a process to return the drug injection rate to its pre-increase state, thereby transitioning to the state at point P51' where the drug injection rate is the same as at point P51. Then, at the state indicated by point P51', the data acquisition unit 101 acquires measurement data (third measurement data) again, and the moisture content prediction unit 102 calculates a third predicted value using the third measurement data.

[0072] The adjustment unit 103 then uses the calculated first to third predicted values ​​to determine the effect of increasing the drug injection rate. The same method as for determining the effect of decreasing the drug injection rate can be applied. For example, the adjustment unit 103 may determine that "the predicted value of moisture content has decreased" when condition (1) above is satisfied, that "the predicted value of moisture content remains unchanged" when condition (2) is satisfied, and that "the predicted value of moisture content has increased" when condition (3) is satisfied.

[0073] In EX5, the predicted moisture content at point P52 is lower than that at points P51 and P51', so the result of the drug injection rate increase effect assessment is "predicted moisture content decreases". In this case, as shown in the figure, the adjustment unit 103 increases the drug injection rate again and transitions to the state at point P52.

[0074] After this, similar to EX2, the same process is repeated until the result of the drug injection rate increase effect judgment is either "the predicted value of moisture content increases" or "the predicted value of moisture content remains unchanged". Specifically, first, as shown in the figure, the adjustment unit 103 increases the drug injection rate from the state at point P52 to the state at point P53, and then returns to the drug injection rate at point P52. Then, the drug injection rate increase effect judgment is performed in the state after the drug injection rate has been returned to its original state (the state shown at point P52'). This process is repeated until the drug injection rate is adjusted to the value just before the result of the drug injection rate increase effect judgment is either "the predicted value of moisture content increases" or "the predicted value of moisture content remains unchanged".

[0075] (3: Summary of methods for adjusting the method of adding drugs) As described above, the data acquisition unit 101 may acquire first measurement data related to the properties of the liquid when the method of adding the drug is the first method, second measurement data related to the properties of the liquid after the method of adding the drug changes to the second method, and third measurement data related to the properties of the liquid after the method of adding the drug is changed back from the second method to the first method.

[0076] The moisture content prediction unit 102 calculates the first to third predicted values ​​using the first to third measurement data, and the adjustment unit 103 may adjust the method of adding the drug according to the relationship between the average value of the third predicted value and the first predicted value and the second predicted value. This makes it possible to appropriately adjust the method of adding the drug by reducing the influence of factors other than changes in the method of adding the drug.

[0077] For example, suppose that after the measurement of the first measurement data and before the measurement of the second measurement data, the properties of the supplied liquid change to such an extent that it affects the predicted water content. In this case, the first predicted value will not reflect this change, but the second and third predicted values ​​will.

[0078] By using a third predicted value, in such cases, the influence of changes in the properties of the supplied liquid can be reduced compared to adjusting the method of adding the drug according to the relative magnitudes of the first and second predicted values.

[0079] Furthermore, as explained with reference to Figures 3 to 5, the adjustment unit 103 may repeatedly perform the process of changing the manner in which the drug is added, and the process of adjusting the manner in which the drug is added based on the predicted values ​​of the moisture content prediction unit 102 before and after the change, until the predicted values ​​predicted by the moisture content prediction unit 102 satisfy predetermined conditions. With this configuration, the adjustment of the manner in which the drug is added can be automatically repeated, and a state can be reached in which the moisture content is expected to satisfy the desired conditions.

[0080] The above-mentioned conditions can be set arbitrarily. For example, as in EX1, the condition may be set such that the result of the drug injection rate reduction effect assessment is "an increase in the predicted water content," or as in EX2, the condition may be set such that the result of the drug injection rate increase effect assessment is "an increase in the predicted water content" or "the predicted water content remains unchanged." In addition, for example, conditions may be set such as the predicted water content being below a threshold, or the predicted water content being within a predetermined allowable range.

[0081] [Automatic resumption of drug injection rate adjustment] Furthermore, the information processing device 1 may restart the above-described repetitive processing after a predetermined time has elapsed since the above conditions were met, or when the predicted value predicted by the moisture content prediction unit 102 no longer satisfies the above conditions. Even if the conditions are met once, they may no longer be met over time, etc. However, with this configuration, the repetitive processing is restarted in such cases, so a state in which the moisture content is expected to meet the desired conditions can be automatically maintained.

[0082] For example, the adjustment unit 103 may start a timer countdown when the above conditions are met. Then, the data acquisition unit 101 may acquire first measurement data when the timer detects the elapsed of a predetermined time, and the moisture content prediction unit 102 may calculate a first predicted value using the first measurement data. After that, the drug injection rate can be adjusted by repeating the process in the manner described in EX1 to EX5 above.

[0083] Furthermore, for example, the data acquisition unit 101 may periodically acquire measurement data even during periods when the above-described repetitive processing is not being performed, and the moisture content prediction unit 102 may use this measurement data to calculate a predicted value. The above-described repetitive processing may then be started if the predicted value of the moisture content prediction unit 102 does not meet predetermined conditions (for example, if the predicted value is outside a predetermined acceptable range).

[0084] [Determining whether adjustments are necessary, taking cost into consideration] The judgment threshold ΔW and the adjustment range of the drug injection rate in the above-mentioned conditions (1) to (3) may be set considering the cost required for liquid processing. In other words, the adjustment unit 103 may adjust by increasing the amount of drug added by a predetermined amount if the reduction in processing cost of the dewatered cake due to the reduction in water content, estimated based on the first and second predicted values, is greater than the increase in cost of increasing the amount of drug added by a predetermined amount. This makes it possible to automatically reduce the processing cost of the liquid.

[0085] For example, ΔP and ΔW may be set such that the increase or decrease in processing cost when the drug injection rate is increased or decreased by ΔP% is equal to the increase or decrease in processing cost of the dehydrated cake when the moisture content is increased or decreased by ΔW. To give a specific example, suppose the increase or decrease in processing cost (mainly drug costs) when the drug injection rate is increased or decreased by 0.1% is equal to the increase or decrease in processing cost (expected value is fine) of the dehydrated cake when the moisture content is increased or decreased by 0.4%. In this case, the adjustment unit 103 adjusts the drug injection rate in 0.1% increments and makes an adjustment to decrease the drug injection rate when it is expected that the moisture content will decrease by 0.4% or more.

[0086] Furthermore, the adjustment unit 103 may adjust the drug injection rate so as to minimize the total processing cost. In this case, the adjustment unit 103 only needs to calculate the predicted processing cost from the predicted value predicted by the moisture content prediction unit 102. This allows the drug injection rate to be automatically adjusted to minimize the total processing cost through the same process as in the above examples for adjusting to the drug injection rate that minimizes the predicted moisture content.

[0087] For example, when considering chemical costs and dewatering cake processing costs, the adjustment unit 103 calculates the dewatering cake processing cost from the predicted value predicted by the moisture content prediction unit 102, and also calculates the chemical cost from the chemical injection rate at the time of measurement of the measurement data used to calculate the predicted value. The adjustment unit 103 also calculates the sum of the calculated dewatering cake processing cost and chemical cost as the total processing cost. The adjustment unit 103 then repeats the process of calculating the above total value by changing the chemical injection rate until the above total value is minimized, thereby adjusting to the chemical injection rate that minimizes the total processing cost.

[0088] [Processing flow (overall)] The flow of processing (adjustment method) performed by the information processing device 1 will be explained based on Figure 6. Figure 6 is a flowchart showing an example of processing performed by the information processing device 1. At the start of the processing in Figure 6, a drug is added to the liquid in the flocculator 5 at a predetermined drug injection rate.

[0089] In S1, a process for determining the effectiveness of reducing the drug injection rate is performed. As will be explained in detail later based on Figure 7, the drug injection rate reduction effect determination process performs the "drug injection rate reduction effect determination" explained based on EX3 and EX4 in Figure 4, and the first to third predicted values, which are predicted values ​​of the water content, are calculated. Note that when performing the "drug injection rate reduction effect determination," the drug injection rate may not be restored, as in EX1 in Figure 3.

[0090] In S2, the adjustment unit 103 determines whether the predicted water content decreased or remained unchanged by making adjustments to reduce the drug injection rate based on the first to third predicted values ​​calculated in S1. If the result in S2 is YES, the process proceeds to S3; if the result in S2 is NO, the process proceeds to S4.

[0091] In S2, the adjustment unit 103 may determine NO if, for example, condition (3) below is satisfied. Alternatively, the adjustment unit 103 may determine YES in S2 if condition (1) or (2) below is satisfied. W2 - (W1 + W3) / 2 < - ΔW …(1) -ΔW≦W2-(W1+W3) / 2<ΔW …(2) ΔW≦W2-(W1+W3) / 2 …(3) Normally, reducing the chemical injection rate increases the water content, so the S2 result is often NO. However, for example, if the chemical injection rate at the start of the process in Figure 6 is too high, adjusting to reduce the chemical injection rate may lower the predicted water content. In such cases, the S2 result will be YES.

[0092] In S3, the adjustment unit 103 adjusts the manner in which the drug is added. More specifically, the adjustment unit 103 reduces the drug injection rate, and this post-processing returns to S1. For example, the adjustment unit 103 may reduce the drug injection rate by the same reduction amount as in S1. In S3, the adjustment unit 103 may reduce the drug injection rate by directly controlling the supply device that supplies the drug to the flocculator 5, or by controlling the supply device via another device such as the control device 3. The same applies to S6, which will be described later.

[0093] Thus, the processes S1 to S3 are repeated until S2 is determined to be NO. The processes S1 to S3 can be described as gradually reducing the drug injection rate by a predetermined reduction range until just before an increase in the predicted moisture content is expected.

[0094] In S4, a process for determining the effect of increasing the drug injection rate is performed. As will be explained in detail later based on Figure 8, the "drug injection rate increase effect determination" process, as explained based on EX5 in Figure 5, is performed, and the first to third predicted values, which are predicted values ​​of the water content, are calculated. Note that when performing the "drug injection rate increase effect determination," the drug injection rate may not be reset, as in EX2 in Figure 3.

[0095] In S5, the adjustment unit 103 determines whether the predicted water content has decreased by adjusting the drug injection rate based on the first to third predicted values ​​calculated in S4. If the result in S5 is NO, the process in Figure 6 ends; if the result in S5 is YES, the process proceeds to S6.

[0096] For example, the adjustment unit 103 may determine YES in S5 if the condition in (1) above is satisfied. On the other hand, the adjustment unit 103 may determine NO in S5 if the condition in (2) or (3) above is satisfied.

[0097] In S6, the adjustment unit 103 adjusts the manner in which the drug is added. More specifically, the adjustment unit 103 increases the drug injection rate. For example, the adjustment unit 103 may increase the drug injection rate by the same amount as in S4. After the completion of S6, the process returns to S4.

[0098] Thus, the process from S4 to S6 is repeated until NO is determined in S5. The process from S4 to S6 can be described as a process in which the drug injection rate is gradually increased by a predetermined amount until a decrease in the predicted moisture content can no longer be expected.

[0099] Then, the adjustment unit 103 repeats the processes S1 to S3 until it is determined to be NO in S2, and then repeats the processes S4 to S6, thereby adjusting the drug injection rate to a value that minimizes the water content and is not excessive.

[0100] [Processing flow (process for determining the effect of reducing the drug injection rate)] The drug injection rate reduction effect determination process performed in S1 of Figure 6 will be explained based on Figure 7. Figure 7 is a flowchart showing an example of the drug injection rate reduction effect determination process.

[0101] In S11, the moisture content prediction unit 102 predicts the moisture content. More specifically, the moisture content prediction unit 102 calculates a first predicted value using first measurement data related to the properties of the liquid at the time of drug addition at the time the treatment in S11 is performed.

[0102] In S12, the adjustment unit 103 reduces the drug injection rate. The amount of reduction in the drug injection rate can be predetermined. For example, the adjustment unit 103 may reduce the drug injection rate by ΔP%. Subsequently, in S13, the water content prediction unit 102 predicts the water content from the measurement data measured after the drug injection rate was reduced in S12. More specifically, the water content prediction unit 102 calculates a second predicted value using second measurement data related to the properties of the liquid after the method of drug addition has been changed by the process in S12. The second measurement data is measured after sufficient time has elapsed since the drug injection rate was reduced in S12, so that the effect appears in the measurement data. Hereinafter, this time will be referred to as Δt. Δt may be set to a time of, for example, 5 minutes or more.

[0103] In S14, the adjustment unit 103 returns the drug injection rate to the value it was at before it was reduced in S12. Subsequently, in S15, the water content prediction unit 102 predicts the water content from the measurement data measured after the drug injection rate was returned to its original value in S14. More specifically, the water content prediction unit 102 calculates a third predicted value using third measurement data related to the properties of the liquid after the drug addition method has been returned to the method immediately before S12 by the process in S14. This completes the process shown in Figure 7.

[0104] Furthermore, the third measurement data, like the second measurement data, is measured after sufficient time has elapsed for the effect of changing the drug injection rate to become apparent in the measurement data. This time may be the same as the time (Δt) for the second measurement data. This is also the case in S45 of Figure 8, which will be described later.

[0105] [Processing flow (process for determining the effect of increasing the drug injection rate)] The drug injection rate increase effect determination process performed in S4 of Figure 6 will be explained based on Figure 8. Figure 8 is a flowchart showing an example of the drug injection rate increase effect determination process.

[0106] In S41, the moisture content prediction unit 102 predicts the moisture content. More specifically, the moisture content prediction unit 102 calculates a first predicted value using first measurement data related to the properties of the liquid after the addition of the chemical agent at the time the treatment in S41 is performed.

[0107] In S42, the adjustment unit 103 increases the drug injection rate. The amount of increase in the drug injection rate can be predetermined. For example, the adjustment unit 103 may increase the drug injection rate by the same amount as in S12 in Figure 7 (for example, ΔP%).

[0108] In S43, the moisture content prediction unit 102 predicts the moisture content from the measurement data measured after increasing the drug injection rate in S42. More specifically, the moisture content prediction unit 102 calculates a second predicted value using second measurement data related to the properties of the liquid after the method of drug addition has been changed by the process in S42. The second measurement data is measured after sufficient time has elapsed since increasing the drug injection rate in S42 (for example, after 5 minutes). For example, the second measurement data may be measured after a time (Δt) has elapsed since increasing the drug injection rate in S42, similar to S13 in Figure 7.

[0109] In S44, the adjustment unit 103 returns the drug injection rate to the value it was at before it was increased in S42. Subsequently, in S45, the moisture content prediction unit 102 predicts the moisture content from measurement data taken after a sufficient amount of time (e.g., about 5 minutes) has elapsed since the drug injection rate was returned to its original state in S44. More specifically, the moisture content prediction unit 102 calculates a third predicted value using third measurement data related to the properties of the liquid after the drug addition method has been returned to the state immediately before S42 by the process in S44. This completes the process shown in Figure 8.

[0110] As explained with reference to Figures 6 to 8, the adjustment method of this embodiment includes the steps of predicting the moisture content of a dewatered cake obtained by adding a chemical agent to a liquid containing suspended solids and then dewatering it with a dewatering machine 9, and the steps of calculating a first predicted value using first measurement data related to the properties of the liquid before the manner of chemical addition is changed (S11 / S41), calculating a second predicted value of the moisture content of the dewatered cake using second measurement data related to the properties of the liquid after the manner of chemical addition is changed (S13 / 43), and adjusting the manner of chemical addition based on the first predicted value and the second predicted value (S3 / S6). Thus, it becomes possible to appropriately adjust the manner of chemical addition.

[0111] [Variation] The entity executing each process described in the above embodiments is arbitrary and is not limited to the examples given above. For example, each step of the adjustment method shown in Figures 6 to 8 can be divided among multiple information processing devices. In other words, the adjustment method may be executed by one information processing device 1 or by multiple information processing devices.

[0112] [Examples of implementation using software] The functions of the information processing device 1 (hereinafter referred to as "the device") are programs that cause the device to function as a computer, and these can be realized by programs (adjustment programs) that cause each control block of the device (especially each part included in the control unit 10) to function as a computer.

[0113] 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., memory) as hardware for executing the program. By executing the program using this control device and storage device, the functions described in each of the embodiments are realized.

[0114] The above program may be recorded on one or more computer-readable recording media, not temporary ones. These recording media may or may not be provided by the above device. In the latter case, the program may be supplied to the above device via any wired or wireless transmission medium.

[0115] Furthermore, some or all of the functions of each of the above control blocks can also be realized by logic circuits. For example, an integrated circuit in which logic circuits functioning as each of the above control blocks are formed is also included in the scope of the present invention. In addition, it is also possible to realize the functions of each of the above control blocks by, for example, a quantum computer.

[0116] The present invention is not limited to the embodiments described above, 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]

[0117] 1. Information Processing Device 102 Moisture content prediction section 103 Adjustment section

Claims

1. A water content prediction unit predicts the water content of a dewatered cake obtained by adding a chemical agent to a liquid containing suspended solids to coagulate the suspended solids and then dewatering it using a dewatering machine. The unit calculates a first predicted value using first measurement data related to the properties of the liquid, measured after the addition of the chemical agent and before the manner of chemical agent addition is changed, and calculates a second predicted value using second measurement data related to the properties of the liquid, measured after the addition of the chemical agent and after the manner of chemical agent addition is changed. An information processing apparatus comprising an adjustment unit that adjusts the manner in which the drug is added based on the first predicted value and the second predicted value.

2. A water content prediction unit that predicts the water content of a dewatered cake obtained by adding an agent that coagulates suspended solids to a liquid containing suspended solids and then dewatering it using a dewatering machine, the unit calculating a first predicted value using first measurement data related to the properties of the liquid before the manner of adding the agent is changed, and calculating a second predicted value using second measurement data related to the properties of the liquid after the manner of adding the agent is changed, The system includes an adjustment unit that adjusts the manner in which the drug is added based on the first predicted value and the second predicted value, The adjustment unit is an information processing device that changes the manner in which the drug is added from a first manner to a second manner, and then adjusts the manner in which the drug is added according to the relationship between the average value of the third predicted value predicted by the water content prediction unit and the first predicted value, and the second predicted value, using third measurement data related to the properties of the liquid after returning to the first manner.

3. The information processing apparatus according to claim 1 or 2, wherein the adjustment unit repeatedly performs the process of changing the manner in which the drug is added and the process of adjusting the manner in which the drug is added based on the predicted value of the moisture content prediction unit before and after the change, until the predicted value predicted by the moisture content prediction unit satisfies a predetermined condition.

4. The information processing apparatus according to claim 3, wherein the iterative processing is restarted after a predetermined time has elapsed since the conditions were met, or when the predicted value predicted by the moisture content prediction unit no longer satisfies the conditions.

5. A water content prediction unit that predicts the water content of a dewatered cake obtained by adding an agent that coagulates suspended solids to a liquid containing suspended solids and then dewatering it using a dewatering machine, the unit calculating a first predicted value using first measurement data related to the properties of the liquid before the manner of adding the agent is changed, and calculating a second predicted value using second measurement data related to the properties of the liquid after the manner of adding the agent is changed, The system includes an adjustment unit that adjusts the manner in which the drug is added based on the first predicted value and the second predicted value, The adjustment unit is an information processing device that adjusts the amount of the chemical to be added to a predetermined amount when the reduction in the processing cost of the dewatered cake due to the reduction in moisture content, estimated based on the first predicted value and the second predicted value, is greater than the increase in the cost of increasing the amount of the chemical to be added to a predetermined amount.

6. The information processing apparatus according to claim 1, wherein the first measurement data and the second measurement data are (1) data indicating the size of the flocs in the liquid, or (2) data indicating the supply flow rate of the liquid supplied to the dewatering machine when control is performed to keep the pressure constant when supplying the liquid to the dewatering machine.

7. A method for adjusting the manner in which a drug is added, which is performed by one or more information processing devices, A step of predicting the water content of a dewatered cake obtained by adding a chemical agent to a liquid containing suspended solids and then dewatering it using a dewatering machine, comprising the step of calculating a first predicted value using first measurement data related to the properties of the liquid, measured after the addition of the chemical agent and before the manner of adding the chemical agent is changed, A step of calculating a second predicted value of the water content of the dehydrated cake using second measurement data related to the properties of the liquid, measured after the addition of the agent and after the manner of adding the agent has been changed. A method for adjusting the manner in which the drug is added, comprising the step of adjusting the manner in which the drug is added based on the first predicted value and the second predicted value.

8. An adjustment program for causing a computer to function as an information processing device according to claim 1, wherein the computer functions as the moisture content prediction unit and the adjustment unit.

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