JP2024062253A - Water treatment system, control device, water treatment method and program - Google Patents

Abstract

[Problem] To add an optimal amount of flocculant. [Solution] The system includes an addition device 700 that adds flocculant to water to be treated, an imaging device 500 that images the state of flocculants in the water to which flocculant has been added from the addition device 700, a filtration membrane 300 that filters the water to which flocculant has been added from the addition device 700, a measuring means that measures at least one of the pressure at the inlet of the filtration membrane 300, the filtration flow rate of the filtration membrane 300, and the water level at the filtration membrane 300, and a control device 600 that controls the amount of flocculant added by the addition device 700 based on the state of the flocculants imaged by the imaging device 500 and the value measured by the measuring means. [Selected Figure] Figure 1

Description

The present invention relates to a water treatment system, a control device, a water treatment method, and a program.

In water purification plants, sewage treatment plants, industrial water treatment, wastewater treatment in semiconductor factories, and other wastewater treatment facilities, a coagulant is added to the water being treated, the suspended solids (SS) in the water being treated are coagulated to form flocs, and the flocs are separated by settling or flotation separation. In this case, for example, a technology has been developed that measures the turbidity of the raw water being treated, and calculates the amount of coagulant to be added based on the measured turbidity (see, for example, Patent Document 1).

JP 2007-098236 A

Even if the turbidity of the water is the same, the substances contained in the water may differ if influenced by the surrounding environment, etc., and as a result, the state of the flocculants in the water may differ. Therefore, even if only the turbidity of the water to be treated is monitored, it may not be possible to add the optimal amount of flocculant.

The object of the present invention is to provide a water treatment system, a control device, a water treatment method, and a program that can add an optimal amount of coagulant.

The water treatment system of the present invention comprises:
An adding means for adding a flocculant to the water to be treated;
an imaging means for imaging a state of the flocculant in the water to which the flocculant has been added from the adding means;
A filtering means for filtering the water to which the flocculant has been added from the adding means;
A measuring means for measuring at least one of a pressure at an inlet of the filtering means, a filtering flow rate of the filtering means, and a water level in the filtering means;
The apparatus further comprises a control means for controlling the amount of the flocculant added by the adding means based on the state of the flocculant imaged by the imaging means and the value measured by the measuring means.

The control device of the present invention further comprises:
an image processing unit that quantifies the state of the flocculants based on an image of the flocculants in the water to which the flocculant has been added from the adding means;
The system has a control unit that controls the amount of flocculant added by the adding means based on the state of the flocculant quantified by the image processing unit, and at least one of the pressure at the inlet of a filtration means that filters the water to which the flocculant has been added, the filtration flow rate of the filtration means, and the water level in the filtration means.

The water treatment method of the present invention further comprises:
A process of quantifying the state of the flocculants based on an image of the state of the flocculants in the water to which the flocculant has been added from the adding means;
A process of acquiring at least one of a pressure at an inlet of a filtering means for filtering the water to which the coagulant has been added, a filtration flow rate of the filtering means, and a water level in the filtering means;
A process of controlling the amount of the flocculant added by the adding means is performed based on the quantified state of the flocculant and the acquired value.

In addition, the program of the present invention is
A program for causing a computer to execute the program,
A step of quantifying the state of the flocculants based on an image of the state of the flocculants in the water to which the flocculant has been added from the adding means;
A step of acquiring at least one of a pressure at an inlet of a filtering means for filtering the water to which the coagulant has been added, a filtration flow rate of the filtering means, and a water level in the filtering means;
and a procedure of controlling the amount of the flocculant added by the adding means, based on the quantified state of the flocculant and the acquired value.

In the present invention, an optimal amount of flocculant can be added.

1 is a diagram showing a first embodiment of a water treatment system of the present invention; FIG. 2 is a diagram showing an example of components included in the control device shown in FIG. 1 . 11A and 11B are diagrams for explaining an example of shading processing and differentiation processing; FIG. 3 is a diagram showing an example of a change over time in the amount of flocculant added controlled by the control unit shown in FIG. 2 . 2 is a flowchart for explaining an example of a water treatment method in the water treatment system shown in FIG. 1 . 2 is a flowchart for explaining an example of a water treatment method in the water treatment system shown in FIG. 1 . FIG. 2 is a diagram showing a second embodiment of the water treatment system of the present invention. FIG. 13 is a diagram showing a third embodiment of the water treatment system of the present invention. FIG. 9 is a diagram showing an example of components included in the control device shown in FIG. 8 . 9 is a flowchart for explaining an example of a water treatment method in the water treatment system shown in FIG. 8 . FIG. 13 is a diagram showing a fourth embodiment of the water treatment system of the present invention. FIG. 13 is a diagram showing a fifth embodiment of the water treatment system of the present invention. FIG. 13 is a diagram showing a sixth embodiment of the water treatment system of the present invention. 14 is a diagram showing an example of a change over time in the filtration pressure measured by the two pressure sensors shown in FIG. 13.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
(First embodiment)

Figure 1 is a diagram showing a first embodiment of the water treatment system of the present invention. As shown in Figure 1, the water treatment system in this embodiment has a reaction tank 100, a relay tank 110, a pump 200, a filtration membrane 300, pressure sensors 410, 420, an imaging device 500, a control device 600, an addition device 700, and a flocculant storage tank 710.

The reaction tank 100 is a water tank into which the raw water to be treated flows and stores the water to be treated. The reaction tank 100 has a predetermined capacity. The reaction tank 100 stores the water to be treated for the time required for the addition device 700 to add a coagulant to the water to be treated and form flocs (hereinafter referred to as the reaction time). This reaction time is set based on the water to be treated and the coagulant (addition amount, type, etc.). The reaction tank 100 may be a sealed type. When the imaging device 500 photographs the water inside the sealed reaction tank 100, a photographing window such as a transparent acrylic plate may be installed in the reaction tank 100. In this case, in order to prevent the photographing window from becoming dirty, a mechanism for blowing wipers or cleaning air onto the photographing window may be installed. The reaction tank 100 may be provided with an agitator 101. The agitator 101 is installed in the reaction tank 100 and agitates the water to be treated stored in the reaction tank 100. The structure of the agitator 101 is, for example, a structure in which a rotary motor rotates a blade member. The blade member may be shaped as a propeller or a paddle. The agitator 101 may also be one that uses a submersible pump to agitate the water to be treated. The water to be treated flowing into the reaction tank 100 may be water containing suspended solids, dissolved solids, and other substances that can be removed by flocculation. In addition, a pH adjuster such as caustic soda or hydrochloric acid may be added to the reaction tank 100, and a substance that can adjust the flocculation pH may be injected. The reaction tank 100 may be equipped with a pH meter. The addition device 700 is an addition means that adds the flocculant stored in the flocculant storage tank 710 to the water stored in the reaction tank 100. The addition device 700 adds an amount of flocculant based on an instruction from the control device 600 from the flocculant storage tank 710 to the water stored in the reaction tank 100. By adding the flocculant to the water stored in the reaction tank 100 by the addition device 700, a sufficient reaction time is ensured, enabling stronger flocculation to occur, making it easier for the filtration means to remove the formed flocs, and preventing clogging of the filtration means. The relay tank 110 is a storage tank that stores the water to which the flocculant has been added in the reaction tank 100.

The pump 200 sends water stored in the relay tank 110 to the filtration membrane 300. The filtration membrane 300 is a membrane (filtration means) that filters the water sent from the relay tank 110 using the pump 200. As the filtration membrane 300, for example, a microfiltration membrane (MF membrane), an ultrafiltration membrane (UF membrane), a nanofiltration membrane (NF membrane), a reverse osmosis membrane (RO membrane), etc., or any combination of these can be used, but for the purpose of suppressing clogging due to coagulation treatment, a combination in which an RO membrane is provided after the MF membrane or UF membrane is desirable. The water passing method of the filtration membrane 300 may be a cross-flow method or a dead-end method. The pressure sensor 410 is a measurement means that measures the pressure of the water sent from the relay tank 110 using the pump 200. In other words, the pressure sensor 410 measures the pressure of the inlet (primary side) which is the front stage of the filtration membrane 300. The pressure sensor 420 is a measurement means that measures the pressure of the water that has permeated the filtration membrane 300. In other words, the pressure sensor 420 measures the pressure at the outlet (secondary side) downstream of the filtration membrane 300. Each of the pressure sensors 410 and 420 notifies the control device 600 of the measured pressure value.

The imaging device 500 is an imaging means for imaging the state of flocculants (flocs) in the water to be treated stored in the reaction tank 100 to which the flocculant has been added from the addition device 700. The imaging device 500 is not particularly limited as long as it can image flocs, but for example, from the viewpoint of maintainability, a non-wet image sensor (camera) that captures an image of water is preferable. The imaging device 500 is preferably an infrared sensor. The imaging device 500 may be a camera that captures an image of the water in the reaction tank 100 at a time interval equal to or less than a preset time interval (for example, a video camera that captures images continuously). The imaging device 500 outputs image data showing the captured image to the control device 600. The control device 600 is a control means for controlling the amount of flocculant added by the addition device 700 based on the state of the flocculants in the image shown by the image data output from the imaging device 500 and the values measured by the pressure sensors 410 and 420.

Figure 2 is a diagram showing an example of components included in the control device 600 shown in Figure 1. As shown in Figure 2, the control device 600 shown in Figure 1 has an image processing unit 610 and a control unit 620. Note that Figure 2 shows only the main components related to this embodiment among the components included in the control device 600 shown in Figure 1.

The image processing unit 610 quantifies the feature amount of the aggregate contained in the image shown by the image data output from the imaging device 500 as the aggregation state of the aggregate. By making the aggregation state of the aggregate (floc) a numerical value like a feature amount and using this numerical value in the calculation process, control based on the aggregation state (for example, injection control of the flocculant) can be realized. The image processing unit 610 may detect pixels in which the color difference (for example, the difference between the RGB values) of adjacent pixels in the image shown by the image data output from the imaging device 500 is equal to or greater than a threshold, and quantify the edge pixels, which are the sum of the number of detected pixels per unit area (imaging range), as the feature amount of the aggregate. The filtration device is also affected by clogging caused by fine flocs. Therefore, in order to quantify fine flocs, it is necessary to quantify the flocs in units smaller than the flocs. By using the edge pixel number, the surface area of the flocs can be quantified as the number of pixels. Therefore, by using the edge pixel number, stable injection control can be performed even for fine flocs that clog the filtration device. The image processing unit 610 notifies the control unit 620 of the quantified state (feature amount) of the aggregate. The image processing unit 610 may use a trained model that inputs image data output from the imaging device 500 and outputs the feature amount of the aggregate contained in the image shown by the image data, the amount of aggregate required to be added, the timing of adding the flocculant, etc., and notifies the control unit 620 of information acquired (inferred) from the trained model.

The image processing unit 610 may calculate the feature amount by performing shading processing and differentiation processing on the image data output from the imaging device 500, for example. The processing in the image processing unit 610 in this case will be described below. The image processing unit 610 performs shading processing on the image data output from the imaging device 500. This shading processing is also called projection processing, and is processing that digitizes the shading (light and dark) of the image into three or more levels of gradation, for example, 256 levels of gradation (0 to 255 gradations). The image processing unit 610 performs differentiation processing on the result of the shading processing. Specifically, the image processing unit 610 performs differentiation processing on the numerical data that is the result of the shading processing, and calculates the rate of change of the numerical data (gradation). The image processing unit 610 calculates the feature amount based on the result of the differentiation processing.

FIG. 3 is a diagram for explaining an example of shading processing and differentiation processing. FIG. 3(a) shows an example of an image captured by the imaging device 500. In the image shown in FIG. 3(a), two aggregates exist with parts of them overlapping each other. The image processing unit 610 judges the shading (brightness) of this image and quantifies it (shading processing). FIG. 3(b) is a graph showing the quantification of the shading (brightness) at A-A' in the image shown in FIG. 3(a). As shown in FIG. 3(b), each shading (each brightness) at A-A' in the image shown in FIG. 3(a) is a numerical value corresponding to each, and is shown in the graph. The image processing unit 610 calculates the rate of change (absolute value) of shading (brightness) by performing differentiation processing based on the numerical value calculated by the shading processing as shown in FIG. 3(b). In other words, the image processing unit 610 detects the change point (edge) of the numerical data of shading (brightness) shown in the graph. FIG. 3(c) is a graph showing the result of differential processing performed on the result of shading processing. As shown in FIG. 3(c), the change points and change rates of the numerical data of shading (brightness) are detected. The signal in FIG. 3(c) indicates the change rate (absolute value) of shading (brightness). The differential value is large in a place where the change in shading is large and may become an edge. The image processing unit 610 may calculate the number of pixels of the edge obtained as a result of the differential processing as a feature amount, or may calculate the number of pixels of the edge that is equal to or greater than a predetermined change rate as a feature amount. By such processing, the state of the aggregate can be determined using the number of edge pixels as a feature amount. The image processing unit 610 may also calculate the feature amount by multiplying the number of pixels of the edge obtained as a result of the differential processing (the number of change points of shading) by a coefficient corresponding to the magnitude of the change rate.

The control unit 620 controls the amount of flocculant added by the addition device 700 based on the state (characteristics) of the flocculants digitized by the image processing unit 610 and the pressure values notified by the pressure sensors 410 and 420. Specifically, the control unit 620 calculates the difference between the pressure values notified by the pressure sensors 410 and 420, and controls the amount of flocculant added by the addition device 700 based on the calculated difference (filtration pressure) and the state (characteristics) of the flocculants digitized by the image processing unit 610. Note that signals and notifications between the devices may be exchanged (sent and received) wirelessly or by wire (the same applies to the following explanation).

A specific example of the processing in the control unit 620 will be described below. The control unit 620 controls the addition device 700 so as to change the amount of flocculant added from the flocculant storage tank 710 based on the state of the flocculant digitized by the image processing unit 610 every time a first specified time set in advance has elapsed. The first specified time is preferably equal to or less than the residence time from the reaction tank 100 to which the flocculant is added to the inlet of the filtration membrane 300 device, and more preferably, the residence time is a time subsequent to the reaction tank 100. The control unit 620 controls the addition device 700 so as to change the lower limit of the amount of flocculant added from the flocculant storage tank 710 based on the change (for example, the change per unit time) of the difference (filtration pressure) between the pressure value notified from the pressure sensor 410 and the pressure value notified from the pressure sensor 420 every time a second specified time set in advance has elapsed after the first specified time has elapsed. The second specified time is preferably set to the interval immediately after the backwash process of the filtration membrane 300 device. The filtration pressure is the pressure PI1 on the primary side (inlet side) of the filtration membrane 300, or the difference between the pressure PI1 on the primary side (inlet side) of the filtration membrane 300 and a predetermined value. In addition, it is desirable to use the difference between the pressure PI1 on the primary side (inlet side) of the filtration membrane 300 and the pressure PI2 on the secondary side (outlet side) of the filtration membrane 300 as the filtration pressure. By using the pressure PI2 on the secondary side (outlet side) of the filtration membrane 300 to calculate the filtration pressure, the measurement accuracy of the filtration pressure in the filtration membrane 300 is improved. A plurality of pressure sensors may be provided at the inlet of the filtration membrane 300, and the average value of the pressure values measured by each of the plurality of pressure sensors may be used as the pressure value on the primary side. In addition, the formula used to calculate this filtration pressure may be used in a constant flow rate filtration operation in which the output of the supply pump and the valve opening are adjusted so that the amount of filtrate is constant. In addition, the second specified time is longer than the first specified time. For example,
Second specified time=First specified time×n (n is a natural number equal to or greater than 2)
For example, the first specified time may be, for example, 5 minutes, and the second specified time may be, for example, 30 minutes. The control unit 620 includes two timers for measuring the first specified time and the second specified time, respectively, and each timer is reset when it reaches the first specified time and when it reaches the second specified time, respectively.

Figure 4 is a diagram showing an example of the change over time in the amount of flocculant added controlled by the control unit 620 shown in Figure 2. The vertical axis shown in Figure 4 is managed, for example, by the flocculant addition concentration mg/L, mol/L, etc. relative to the amount of water to be treated. The vertical axis may also be a value indicating the output of the addition device 700 that indicates the amount (ratio) of flocculant added. Examples of values indicating the output include pump output (%), pump frequency (Hz), and pump rotation speed (rpm). In the example shown in Figure 4, the addition device 700 is controlled so that a predetermined amount of flocculant is added at the time when the addition of the flocculant is started. In addition, the lower limit at that time is a predetermined value. Thereafter, until the first specified time is reached, an amount of flocculant added according to the state (characteristics) of the flocculant quantified by the image processing unit 610 is added. When the first specified time is reached, the image processing unit 610 digitizes the state (feature amount) of the flocculant contained in the image shown by the image data output from the imaging device 500, and the control unit 620 changes the amount of flocculant added from the flocculant tank 710 based on the feature amount calculated by the image processing unit 610. At this time, the control unit 620 compares the feature amount calculated by the image processing unit 610 with a preset threshold value. If the feature amount calculated by the image processing unit 610 is smaller than the threshold value as a result of the comparison, the control unit 620 increases the amount of flocculant added from the flocculant tank 710. On the other hand, if the feature amount calculated by the image processing unit 610 is larger than the threshold value as a result of the comparison, the control unit 620 decreases the amount of flocculant added from the flocculant tank 710. The amount of increase (increase width) and the amount of decrease (decrease width) are preset amounts. The increase and decrease may be calculated based on the water quality (SS concentration, turbidity, etc.), water temperature, and pH value measured by a water quality meter, a water temperature meter, and a pH meter provided in the reaction tank 100. The increase and decrease may also be values obtained from a learning model that uses machine learning with parameters such as other operating data. In the example shown in FIG. 4, when the first specified time has elapsed from the start, the feature amount calculated by the image processing unit 610 is below the threshold, so the control unit 620 increases the amount of flocculant added from the flocculant storage tank 710. After that, the control device 600 repeats the above comparison and the process of changing the amount added every first specified time until the second specified time is reached.

When the second specified time (t1 shown in FIG. 4) is reached, the control unit 620 calculates the amount of change per unit time from the difference between the pressure value notified by the pressure sensor 410 at the start of the second specified time and the pressure value notified by the pressure sensor 420 to the difference between the pressure value notified by the pressure sensor 410 at the time the second specified time is reached and the pressure value notified by the pressure sensor 420. The control unit 620 compares the calculated amount of change in the pressure difference (the rate of increase in the filtration pressure) with a preset threshold value. If the calculated amount of change in the pressure difference is smaller than the threshold value, the control unit 620 lowers the lower limit value of the amount of flocculant added from the flocculant storage tank 710. On the other hand, if the calculated amount of change in the pressure difference is larger than the threshold value, the control unit 620 raises the lower limit value of the amount of flocculant added from the flocculant storage tank 710 (the "changed lower limit value" shown in FIG. 4). After that, the same process as that performed until the second specified time is reached is repeated until the second specified time is reached again. The range by which the lower limit value is raised or lowered is a preset amount. For example, from the viewpoint of improving the accuracy of control, the range by which the lower limit value is raised or lowered may be calculated based on the water quality, water temperature, and pH value measured by a water quality meter, a water temperature meter, and a pH meter provided in the reaction tank 100. The range by which the lower limit value is raised or lowered may be a value obtained from a learning model that is machine-learned using parameters such as the amount of flocculant added and the operating data of the filtration membrane device.

The water treatment method in the water treatment system shown in FIG. 1 will be described below. FIGS. 5 and 6 are flow charts for explaining an example of the water treatment method in the water treatment system shown in FIG. 1. Here, an example will be described in which the image processing unit 610 performs the above-mentioned shading process and differentiation process to calculate the feature amount of the aggregate.

First, the control unit 620 controls the addition device 700 so that a predetermined amount of flocculant is added from the flocculant storage tank 710 to the water stored in the reaction tank 100. The control unit 620 also starts timers that measure the first and second specified times described above. Thereafter, the control unit 620 determines whether the second specified time has elapsed (step S1). If the second specified time has not elapsed, the control unit 620 determines whether the first specified time has elapsed (step S2). If the first specified time has not elapsed, the process of step S1 is performed.

When the first specified time has elapsed, the imaging device 500 captures an image of the inside of the reaction tank 100, and the captured image is acquired by the control device 600 (step S3). The image processing unit 610 then performs shading processing on the image acquired in the control device 600 (step S4). Next, the image processing unit 610 differentiates the numerical data resulting from the shading processing (step S5). The image processing unit 610 then calculates a feature amount based on the result of the differentiation processing (step S6). As a result, the image processing unit 610 detects pixels in which the color difference between adjacent pixels in the image represented by the image data output from the imaging device 500 is equal to or greater than a threshold, and calculates edge pixels, which are the sum of the number of detected pixels per unit area (imaging range).

The control unit 620 compares the calculated feature amount with a preset threshold value (feature amount threshold value) (step S7). If the calculated feature amount is smaller than the feature amount threshold value, the control unit 620 controls the addition device 700 to increase the amount of flocculant added from the flocculant storage tank 710 (step S8). If the calculated feature amount and the feature amount threshold value are the same value, the control unit 620 controls the addition device 700 to maintain the amount of flocculant added from the flocculant storage tank 710 (step S9). If the calculated feature amount is larger than the feature amount threshold value, the control unit 620 controls the addition device 700 to decrease the amount of flocculant added from the flocculant storage tank 710 (step S10). After the processing of steps S8, S9, and S10, the processing of step S1 is performed.

When the second specified time has elapsed in step S1, the control unit 620 calculates the filtration pressure of the pressures notified by the pressure sensors 410 and 420 (step S11). The control unit 620 calculates the filtration pressure rise rate, which is the amount of change in the calculated filtration pressure per unit time (step S12). The control unit 620 compares the calculated filtration pressure rise rate with a preset threshold value (rate threshold value) (step S13).

If the calculated filtration pressure rise rate is smaller than the rate threshold, the control unit 620 lowers the lower limit value when changing the amount of flocculant added from the flocculant tank 710 (step S14). If the calculated filtration pressure rise rate and the rate threshold are the same value, the control unit 620 maintains the lower limit value when changing the amount of flocculant added from the flocculant tank 710 (step S15). If the calculated filtration pressure rise rate is larger than the rate threshold, the control unit 620 raises the lower limit value when changing the amount of flocculant added from the flocculant tank 710 (step S16). After steps S14, S15, and S16 are processed, step S1 is processed.

In the above-mentioned embodiment, the water to be treated may contain suspended solids or substances to be insolubilized. The flocculant added from the flocculant tank 710 may be an inorganic flocculant, an organic coagulant, or a polymer (polymer flocculant). When the flocculant added from the flocculant tank 710 is an inorganic flocculant, the flocculant may be an aluminum-based (PAC, aluminum sulfate, etc.), an iron-based (polyferric chloride, ferric chloride), etc., and is not particularly limited. When the flocculant added from the flocculant tank 710 is a polymer, the flocculant may be a cation or an anion. Since adjustment of the inorganic flocculant is important in the flocculation treatment, it is preferable to control it using an inorganic flocculant. The inorganic flocculant neutralizes the charge of suspended solids dispersed in the water to be treated, forming microflocs that become the nucleus of floc formation. If the charge neutralization by the inorganic flocculant is not performed well, the effect of the polymer flocculant added thereafter cannot be fully exerted, and the quality of the treated water deteriorates. Furthermore, if too much inorganic coagulant is added, the inorganic coagulant itself becomes excess sludge, which increases running costs such as sludge disposal costs.

ここで、Ｃ_nは凝集変化量、Ａ_n-1は凝集剤の添加量変更前のエッジピクセル数、Ａ_nは凝集剤の添加量変更後のエッジピクセル数、Ｐ_n-1は凝集剤の添加量変更前の添加量、Ｐ_nは凝集剤の添加量変更後の添加量である。 Furthermore, although the number of edge pixels is taken as an example of the feature amount, the feature amount may be the amount of change in aggregation calculated using the following (Equation 1).

Here, C _n is the amount of change in coagulation, A _n-1 is the number of edge pixels before the amount of coagulant added is changed, A _n is the number of edge pixels after the amount of coagulant added is changed, P _n-1 is the amount of coagulant added before the amount of coagulant added is changed, and P _n is the amount of coagulant added after the amount of coagulant added is changed.

In the above example, the control was performed using the differential pressure (filtration pressure) between the pressure in the front stage (primary side) and the pressure in the rear stage (secondary side) of the filtration membrane 300, but the above control may be performed using the filtration flow rate of the filtration membrane 300. In this case, a flow meter may be provided as a measurement means instead of the pressure sensors 410 and 420, and when the value of the flow rate to the filtration membrane 300 is smaller than a predetermined threshold value, the lower limit value may be increased, and when the value of the flow rate to the filtration membrane 300 is larger than a predetermined threshold value, the lower limit value may be decreased. In addition, when the filtration pressure and the flow rate are used, the filtration flux per unit pressure may be calculated using the following (Equation 2) and used to control the amount of flocculant added.
Filtration flux per unit pressure = filtration flow rate / filtration area / filtration pressure (Equation 2)
The filtration flow rate may be a value obtained by directly measuring the flow rate of the secondary side (permeation side) of the filtration device, or a value obtained by indirectly measuring the flow rate of the liquid passed through the filtration device, such as a value obtained by subtracting the circulation flow rate from the supply flow rate to the filtration device. The filtration area is the membrane area of an ultrafiltration membrane or a reverse osmosis membrane, or the cross-sectional area of a sand filter medium. In addition, when calculating the filtration flux, correction may be made according to the temperature and density of the water to be treated.

In this manner, in this embodiment, the control device 600 controls the amount of flocculant added to the water to be treated by the addition device 700 based on the state of the flocculants in the water to be treated to which the flocculant has been added and the pressure difference before and after the filtration membrane 300 provided in the subsequent stage, that is, the change in the difference between the inlet pressure and the outlet pressure of the filtration membrane 300. At this time, the control device 600 digitizes the state (characteristics) of the flocculants based on the image captured by the imaging device 500, and changes the amount of flocculant added calculated based on the water quality of the water to be treated according to the state (characteristics) of the flocculants. In addition, the control device 600 controls the lower limit value for changing the amount of flocculant added according to the change (rising speed) in the pressure difference before and after the filtration membrane 300. This allows the optimal amount of flocculant to be added. In addition to controlling the amount of flocculant added based on the characteristic values, controlling the lower limit value of the amount of flocculant added based on operating data such as flow rate and pressure can further avoid clogging of the filtration device and allow the entire water treatment facility to operate stably. When the filtration pressure of the filtration membrane increases, the lower limit of the amount of coagulant added can be increased to increase the removal rate of organic matter and SS, which are the targets of removal by the coagulation process and cause clogging of the filtration membrane, and thus the increase in the filtration pressure of the filtration membrane can be suppressed. On the other hand, when the increase in the filtration pressure of the filtration membrane is gradual, the amount of coagulant added can be reduced by lowering the lower limit of the amount of coagulant added. These effects make it possible to optimize the running costs of coagulants, etc., while suppressing the increase in the filtration pressure of the filtration membrane.

The pressure sensor may be a sensor capable of detecting absolute pressure or gauge pressure. Since gauge pressure is linked to changes in atmospheric pressure, it is preferable that the pressure sensor is a sensor capable of detecting absolute pressure. In addition, it is preferable that the pressure measured by the pressure sensor is water pressure (kPa), but it is also possible to measure a head difference ( _mmH2O ) or a mercury column (mmHg) as an alternative to pressure, and use the measured value for control, or to convert the measured value into pressure and use it for control.

In water treatment facilities, in order to remove suspended solids from the raw water to be treated, a wide variety of water treatment technologies are used, including coagulation treatment, in which a coagulant is added to the raw water to coarsen the suspended solids, and sedimentation and flotation separation treatments, which separate the aggregates (flocs) generated by the coagulation treatment into solid and liquid. The concentration and properties of suspended solids in the raw water can change over time, and in order to stably remove suspended solids, the amount of coagulant injected must be appropriately adjusted to match the changes in the raw water. A common technique is to calculate a relational equation in advance to calculate the necessary amount of coagulant to be injected based on the turbidity concentration of the water to be treated and the value of a fine particle counter, and then use this to control the injection of the coagulant.

However, even if the turbidity of the treated water is the same, the amount of coagulant required may differ. If the treated water deviates from the preset conditions and flows in, the amount of coagulant added may be insufficient and not properly controlled, which may cause the solid-liquid separated treated water to deteriorate. In addition, when the coagulated water is filtered using a filtration device, if the amount of coagulant added is small, the filtration pressure before and after the filtration device may increase due to dissolved substances such as organic matter remaining in the treated water, and the amount of treated water may decrease. In addition, if an excessive amount of coagulant is added to the treated water, the load on the solid-liquid separation device in the downstream increases. As a result, there is a risk of SS leaks and clogging of the filtration device. In addition, the chemical costs of the coagulant and pH adjuster (caustic soda, etc.) added to the treated water will increase, and the amount of sludge generated from the coagulant will increase, so the sludge disposal costs will also increase. In addition, when membrane filtration is used as the filtration device, if the increase in filtration pressure before and after the filtration device becomes significant, it will be necessary to carry out chemical cleaning using acids or alkalis, which will incur cleaning costs. There are disadvantages such as the need to stop operation of the equipment to perform chemical cleaning and the need to add a backup line.

In this embodiment, the amount of coagulant added can be optimally controlled while suppressing the increase in filtration pressure before and after the filtration device, even with fluctuating raw water. This allows the entire water treatment system to operate stably, and further optimizes costs.
Second Embodiment

Figure 7 is a diagram showing a second embodiment of the water treatment system of the present invention. As shown in Figure 7, the water treatment system in this embodiment has a reaction tank 100, a relay tank 110, a pump 200, a sand filtration device 301, pressure sensors 410, 420, an imaging device 500, a control device 600, an addition device 700, and a flocculant storage tank 710. The reaction tank 100, the relay tank 110, the pump 200, the pressure sensors 410, 420, the imaging device 500, the control device 600, the addition device 700, and the flocculant storage tank 710 are each the same as those in the embodiment shown in Figure 1.

The sand filter 301 is a filtering means arranged in place of the filter membrane 300 in the first embodiment. The sand filter 301 filters the water to be treated using a sand layer as a filter medium. A pressure sensor 410 is arranged in front of the sand filter 301, and a pressure sensor 420 is arranged in the rear of the sand filter 301. With this configuration, the pressures before and after the sand filter 301 are measured. The control based on these pressures in the control device 600 is the same as in the first embodiment.

In this manner, in this embodiment, the control device 600 controls the amount of flocculant added to the water to be treated by the addition device 700 based on the state of the flocculants in the water to be treated to which the flocculant has been added and the change in the pressure difference before and after the sand filtration device 301 provided in the subsequent stage. At this time, the control device 600 digitizes the state (characteristic amount) of the flocculants based on the image captured by the imaging device 500, and changes the amount of flocculant added calculated based on the water quality of the water to be treated according to the state (characteristic amount) of the flocculants. In addition, the control device 600 controls the lower limit value for changing the amount of flocculant added according to the change in the pressure difference before and after the sand filtration device 301 (rising speed). This allows the optimal amount of flocculant to be added. In addition to controlling the amount of flocculant added based on the characteristic amount, the lower limit value of the amount of flocculant added based on operating data such as flow rate and pressure can be controlled to further avoid clogging of the filtration device and operate the entire water treatment facility stably. In this manner, the amount of flocculant added can be optimally controlled for the flocculant added while suppressing the increase in filtration pressure before and after the filtration device for the fluctuating raw water. This allows the entire water treatment system to operate stably and further optimizes incurred costs.
Third Embodiment

Figure 8 is a diagram showing a third embodiment of the water treatment system of the present invention. As shown in Figure 8, the water treatment system in this embodiment has a reaction tank 100, a sand filter device 302, a water level gauge 430, an imaging device 500, a control device 601, an addition device 700, and a flocculant storage tank 710. The reaction tank 100, the imaging device 500, the addition device 700, and the flocculant storage tank 710 are each the same as those in the embodiment shown in Figure 1.

The sand filter 302 is a gravity type sand filter, and is a filtering means in which the water to be treated flows in from the top and the treated water that has permeated the sand layer, which serves as the filter medium, is extracted from the bottom. The water level gauge 430 measures the water level of the water to be treated in the sand filter 302. The water level gauge 430 notifies the control device 601 of the measured water level value.

Figure 9 is a diagram showing an example of components included in the control device 601 shown in Figure 8. As shown in Figure 9, the control device 601 shown in Figure 8 has an image processing unit 610 and a control unit 621. The image processing unit 610 is the same as that in the first embodiment. Note that Figure 9 shows only the main components related to this embodiment among the components included in the control device 601 shown in Figure 8.

The control unit 621 controls the amount of flocculant added by the addition device 700 based on the state (characteristics) of the flocculants quantified by the image processing unit 610 and the water level value notified by the water level meter 430. Specifically, when controlling the amount of flocculant added by the addition device 700 based on the state (characteristics) of the flocculants quantified by the image processing unit 610, the control unit 620 controls the lower limit of the amount added based on the water level value notified by the water level meter 430.

The water treatment method in the water treatment system shown in FIG. 8 will be described below. FIG. 10 is a flowchart for explaining an example of the water treatment method in the water treatment system shown in FIG. 8. First, the processing of steps S1 to S10 described using the flowchart shown in FIG. 5 is performed.

If the second specified time has elapsed in step S1, the control unit 621 acquires the water level value notified by the water level gauge 430 (step S21). The control unit 621 calculates the water level rise speed, which is the amount of change per unit time of the acquired water level value (step S22). The control unit 621 compares the calculated water level rise speed with a preset threshold value (speed threshold) (step S23).

If the calculated water level rise speed is smaller than the speed threshold, the control unit 621 lowers the lower limit value when changing the amount of flocculant added from the flocculant tank 710 (step S24). If the calculated water level rise speed and the speed threshold are the same value, the control unit 621 maintains the lower limit value when changing the amount of flocculant added from the flocculant tank 710 (step S25). If the calculated water level rise speed is larger than the speed threshold, the control unit 621 raises the lower limit value when changing the amount of flocculant added from the flocculant tank 710 (step S26). After the processing of steps S24, S25, and S26 is performed, the processing of step S1 is performed. For example, if the allowable upper limit water level is 100%, if the water level rise speed is 10%/h or more, the lower limit value is raised, if the water level rise speed is between 10 and 5%/h, the lower limit value is maintained, and if it is less than 5%/h, the lower limit value is lowered.

In this manner, in this embodiment, the control device 601 controls the amount of flocculant added to the water to be treated by the addition device 700 based on the state of the flocculants in the water to be treated to which the flocculant has been added and the change in the water level of the water to be treated in the sand filtration device 302 provided in the subsequent stage. At this time, the control device 601 digitizes the state (characteristic amount) of the flocculants based on the image captured by the imaging device 500, and changes the amount of flocculant added calculated based on the water quality of the water to be treated according to the state (characteristic amount) of the flocculants. In addition, the control device 601 controls the lower limit value for changing the amount of flocculant added according to the change in the water level of the water to be treated in the sand filtration device 302 (rising speed). This allows the optimal amount of flocculant to be added. In addition to controlling the amount of flocculant added based on the characteristic amount, the lower limit value of the amount of flocculant added based on the water level of the water to be treated in the filtration device can be controlled to further avoid clogging of the filtration device and stably operate the entire water treatment facility. In this manner, the amount of flocculant added can be optimally controlled for fluctuating raw water while suppressing a decrease in the filtering capacity of the filtration device. This allows the entire water treatment system to be operated stably, and further optimizes costs. When using a gravity filter or other filter that utilizes a head difference to pass water through the filter, it is more desirable to control the water level rather than using the filtration pressure before and after the filter.
(Fourth embodiment)

Figure 11 is a diagram showing a fourth embodiment of the water treatment system of the present invention. As shown in Figure 11, the water treatment system in this embodiment has a raw water tank 120, a pump 200, an agitator 800, a filtration membrane 300, pressure sensors 410, 420, an imaging device 500, a control device 600, an addition device 700, and a flocculant storage tank 710. The pump 200, the filtration membrane 300, the pressure sensors 410, 420, the imaging device 500, the control device 600, the addition device 700, and the flocculant storage tank 710 are each the same as those in the embodiment shown in Figure 1.

（式２）における各パラメータを以下に示す。
Ａｉ：撹拌翼ｉの運動方向に直角な面積（ｍ²）
ｖｉ：撹拌翼ｉの平均速度（ｍ／ｓ）
ν：水の動粘性係数（ｍ²／ｓ）（１．００４×１０^-6ｍ²／ｓ）
Ｖ：反応槽容量（ｍ³）
Ｃ：撹拌翼の抵抗係数（－）（１．５） The raw water tank 120 is a water tank in which the water to be treated is stored. The agitator 800 agitates the water that is sucked up from the raw water tank 120 using the pump 200 and to which a flocculant is added from the adder 700. The shape and structure of the agitator 800 are not particularly specified as long as it can agitate water. Examples of the agitator 800 include an in-line mixer and an orifice plate. The imaging device 500 images the water agitated by the agitator 800. The point imaged by the imaging device 500 may be the water in the agitator 800, the water flowing through the flow path (piping) from the agitator 800 to the filtration membrane 300, or the water stored in the water tank if a water tank is provided between the agitator 800 and the filtration membrane 300. In this case, the agitator 800, the flow path, and the water tank are flocculation forming means for forming flocs in the water. One of the indicators of the agitation conditions in flocculation is the agitation strength (agitation G value). The agitation G value is generally expressed by the following formula (2). In forming flocs by adding a coagulant to the water to be treated, if the agitation intensity (agitation G value) is too small, the growth of the flocs will be slow. On the other hand, if the agitation intensity (agitation G value) is too large, the flocs will be destroyed by shear force. The agitation intensity for agitating the water to be treated to which a coagulant has been added may be, for example, about 100 to 300/s.

The parameters in (Equation 2) are as follows:
Ai: Area perpendicular to the direction of motion of the impeller i (m ² )
vi: average speed of stirring blade i (m / s)
ν: Dynamic viscosity coefficient of water (m ² /s) ( ^{1.004×10 −6} m ² /s)
V: Reactor volume (m ³ )
C: Resistance coefficient of the stirring blade (-) (1.5)

In this manner, in this embodiment, the control device 600 controls the amount of flocculant added to the water to be treated by the addition device 700 based on the state of the flocculant in the water to be treated to which the flocculant has been added and the change in the pressure difference before and after the filtration membrane 300 provided in the subsequent stage. At this time, the control device 600 digitizes the state (characteristic amount) of the flocculant based on the image captured by the imaging device 500, and changes the amount of flocculant added calculated based on the water quality of the water to be treated according to the state (characteristic amount) of the flocculant. In addition, the control device 600 controls the lower limit value for changing the amount of flocculant added according to the change in the pressure difference before and after the filtration membrane 300 (rising speed). In addition to controlling the amount of flocculant added based on the characteristic amount, by controlling the lower limit value of the amount of flocculant added based on the operating data such as the flow rate and pressure, it is possible to more effectively avoid clogging of the filtration device and to stably operate the entire water treatment facility. Furthermore, in this embodiment, the water to be treated that the imaging device 500 captures may be water to be treated after the flocculant has been added and stirred, and is not limited to water flowing through a flow path or stored in a water tank. Therefore, it is possible to add an optimal amount of flocculant without having to prepare equipment such as a water tank in which to store the water to be treated for imaging.
Fifth embodiment

Figure 12 is a diagram showing a fifth embodiment of the water treatment system of the present invention. As shown in Figure 12, the water treatment system in this embodiment has a reaction tank 100, a flocculation tank 130, a flotation tank 140, a relay tank 110, a pump 200, a filtration membrane 300, pressure sensors 410, 420, an imaging device 500, a control device 600, an addition device 700, and a flocculant storage tank 710. The reaction tank 100, the pump 200, the filtration membrane 300, the pressure sensors 410, 420, the imaging device 500, the control device 600, the addition device 700, and the flocculant storage tank 710 are the same as those in the first embodiment shown in Figure 1. The relay tank 110 is the same as that in the second embodiment shown in Figure 7.

The flocculation tank 130 is a water tank into which the water to be treated that has been treated in the reaction tank 100 is poured. The flocculation tank 130 is provided to promote the formation of flocs in the water to be treated. For example, a polymer is poured into the water to be treated stored in the flocculation tank 130. The flotation tank 140 is a solid-liquid separation tank into which the water to be treated that has been treated in the flocculation tank 130 is poured and which performs floating separation of the water to be treated as solid-liquid separation. In the flotation tank 140, the treated water is separated from floating matter such as scum that has risen to the surface, and the floating matter such as scum is discharged to the outside of the flotation tank 140. The water to be treated that has been treated in the flotation tank 140 is sent to the relay tank 110.

In this manner, in this embodiment, the control device 600 controls the amount of flocculant added to the water to be treated by the addition device 700 based on the state of the flocculants in the water to be treated to which the flocculant has been added and the change in the pressure difference before and after the filtration membrane 300 provided in the subsequent stage. At this time, the control device 600 digitizes the state (characteristics) of the flocculants based on the image captured by the imaging device 500, and changes the amount of flocculant added calculated based on the water quality of the water to be treated according to the state (characteristics) of the flocculants. In addition, the control device 600 controls the lower limit value for changing the amount of flocculant added according to the change in the pressure difference before and after the filtration membrane 300 (rising speed). In addition to controlling the amount of flocculant added based on the characteristic values, by controlling the lower limit value of the amount of flocculant added based on operation data such as flow rate and pressure, it is possible to more effectively avoid clogging of the filtration device and to stably operate the entire water treatment facility. Furthermore, in this embodiment, in order to promote floc formation, a flocculation tank 130 and a flotation tank 140 are provided between the reaction tank 100, in which the imaging device 500 captures the flocculation state, and the filtration membrane 300. Therefore, the filtration device (filtration membrane 300) can be operated more stably, and an optimal amount of flocculant can be added. In addition, instead of the floating tank 140 as a solid-liquid separation means, a settling tank for performing coagulation precipitation as solid-liquid separation may be used. In addition, the solid-liquid separation means may be provided in the front stage of the sand filtration device 301 in the second embodiment shown in FIG. 7, in the front stage of the sand filtration device 302 in the third embodiment shown in FIG. 8, or in the front stage of the filtration membrane 300 in the fourth embodiment shown in FIG. 11 (downstream of the imaging point of the imaging device 500). By providing the solid-liquid separation means in the front stage of the filtration device, the load on the filtration device due to the clogging substances can be reduced, and the filtration device can be operated more stably.
Sixth embodiment

Figure 13 is a diagram showing a sixth embodiment of the water treatment system of the present invention. As shown in Figure 13, the water treatment system in this embodiment has a reaction tank 100, a flocculation tank 130, a flotation tank 140, a relay tank 110, pumps 200, 210, a filtration membrane 300, pressure sensors 410, 420, an imaging device 500, a control device 600, an addition device 700, a flocculant storage tank 710, a treated water tank 150, and a flow meter 440. The reaction tank 100, the pump 200, the filtration membrane 300, the pressure sensors 410, 420, the imaging device 500, the control device 600, the addition device 700, and the flocculant storage tank 710 are the same as those in the first embodiment shown in Figure 1. The relay tank 110 is the same as that in the second embodiment shown in Figure 7. The flocculation tank 130 and the flotation tank 140 are the same as those in the fifth embodiment shown in Figure 12.

In order to operate the filtration device (filtration membrane 300) more stably, a backwashing means for backwashing the filtration membrane 300 may be provided. The treated water tank 150 stores treated water that has permeated the filtration membrane 300. The flow meter 440 measures the flow rate of treated water that permeates the filtration membrane 300 and is supplied to the treated water tank 150. The treated water stored in the treated water tank 150 is pumped up using the pump 210, and chemicals are added (chemical addition backwashing) to pass the water from the secondary side to the primary side of the filtration membrane 300. The chemicals to be added are preferably sodium hypochlorite, caustic soda, hydrochloric acid, oxalic acid, etc. The wastewater after backwashing may be discharged outside the system, or may be returned to a raw water tank (not shown) provided in front of the reaction tank 100 from the viewpoint of water recovery rate.

Figure 14 is a diagram showing an example of the change over time in the filtration pressure between the pressure measured by the pressure sensor 410 and the pressure measured by the pressure sensor 420 shown in Figure 13. As shown in Figure 14, the water collection process is started, and the filtration pressure between the pressure on the primary side and the pressure on the secondary side of the filtration membrane 300 increases over time. By performing backwashing, the filtration pressure temporarily decreases, but when the water collection process is resumed, the filtration pressure increases further. The amount of change per unit time of the difference between the filtration pressure at the start of the water collection process (before backwashing) and the filtration pressure at the start of the water collection process after the backwashing is completed (after backwashing) is the filtration pressure increase rate described in the first embodiment. In the example shown in Figure 14, the slope of the change between the filtration pressure at the start of the water collection process and the filtration pressure at time t1 when the backwashing is completed is the filtration pressure increase rate. In this way, even if the filtration pressure between the pressure on the primary side and the pressure on the secondary side of the filtration membrane 300 increases by performing the water collection process, the filtration pressure can be reduced by performing backwashing thereafter.

In this manner, in this embodiment, the control device 600 controls the amount of flocculant added to the water to be treated by the addition device 700 based on the state of the flocculants in the water to be treated to which the flocculant has been added and the change in the pressure difference before and after the filtration membrane 300 provided in the subsequent stage. At this time, the control device 600 digitizes the state (characteristics) of the flocculants based on the image captured by the imaging device 500, and changes the amount of flocculant added calculated based on the water quality of the water to be treated according to the state (characteristics) of the flocculants. In addition, the control device 600 controls the lower limit value for changing the amount of flocculant added according to the change in the pressure difference before and after the filtration membrane 300 (rising speed). In addition to controlling the amount of flocculant added based on the characteristic values, by controlling the lower limit value of the amount of flocculant added based on operating data such as flow rate and pressure, it is possible to avoid clogging of the filtration device and operate the entire water treatment facility stably. Furthermore, in this embodiment, after the water collection process, the treated water to which the chemical has been added is passed from the secondary side of the filtration membrane 300 to the primary side to backwash the filtration membrane 300. This allows dirt on the primary side of the filtration membrane 300 to be peeled off and improves clogging of the filtration membrane 300. As a result, the filtration device (filtration membrane 300) can be operated more stably, and an optimal amount of coagulant can be added.

The present invention has the effect of being able to add an optimal amount of coagulant even when a sudden increase in turbidity occurs in water treatment due to a typhoon or the like, or when there is a large change in the quality of the water being treated, such as in wastewater treatment.

Although the above description has been given with each component assigned a respective function (process), this allocation is not limited to the above. Furthermore, the configuration of the components is also not limited to the above-described forms, which are merely examples. Furthermore, the above-described embodiments may be combined in any combination.

The processing performed by each of the above-mentioned control devices 600 and 601 may be performed by a logic circuit created for each purpose. As the control device, a PLC (Programmable Logic Controller) or the like may be used. In addition, a computer program (hereinafter referred to as a program) in which the processing contents are described as procedures may be recorded on a recording medium readable by each of the control devices 600 and 601, and the program recorded on the recording medium may be read and executed by each of the control devices 600 and 601. The recording media readable by the control devices 600 and 601 include removable recording media such as floppy disks, optical magnetic disks, digital versatile discs (DVDs), compact discs (CDs), Blu-ray discs (registered trademark) discs, universal serial bus (USB) memories, and SD cards, as well as memory such as read only memory (ROM) and random access memory (RAM) built into the control devices 600 and 601, and hard disc drives (HDDs). The programs recorded on these recording media are read by the CPUs provided in the control devices 600 and 601, and the same processing as described above is performed under the control of the CPUs. Here, the CPUs operate as computers that execute the programs read from the recording media on which the programs are recorded.

A part or all of the above-described embodiments can be described as, but is not limited to, the following supplementary notes.
(Additional Note 1) An adding means for adding a flocculant to the water to be treated;
an imaging means for imaging a state of the flocculant in the water to which the flocculant has been added from the adding means;
A filtering means for filtering the water to which the flocculant has been added from the adding means;
A measuring means for measuring at least one of a pressure at an inlet of the filtering means, a filtering flow rate of the filtering means, and a water level in the filtering means;
A water treatment system having a control means for controlling the amount of flocculant added by the addition means based on the state of the flocculant imaged by the imaging means and the value measured by the measurement means.
(Supplementary Note 2) The water treatment system according to Supplementary Note 1, wherein the control means calculates a characteristic quantity representing the state of the aggregate from the image captured by the imaging means.
(Supplementary Note 3) The water treatment system according to Supplementary Note 2, wherein the control means calculates the characteristic amount based on the number of edge pixels of the aggregate.
(Appendix 4) A water treatment system described in any one of Appendices 1 to 3, wherein the control means controls a lower limit value of the amount of coagulant added by the addition means based on the amount of change in the value measured by the measurement means.
(Appendix 5) The water treatment system according to any one of appendices 1 to 4, wherein the adding means adds an inorganic flocculant as the flocculant.
(Additional Note 6) A water tank into which the treated water flows,
The water treatment system according to any one of claims 1 to 5, wherein the adding means adds the coagulant to the water to be treated that has flowed into the water tank.
(Additional Note 7) Having a backwashing means for backwashing the filtering means,
A water treatment system described in any one of Appendix 1 to 6, wherein the control means controls a lower limit value of the amount of coagulant added by the addition means based on the amount of change in the value measured by the measurement means before and after backwashing the filtration means using the backwashing means.
(Appendix 8) A water treatment system described in any one of appendices 1 to 7, comprising a solid-liquid separation means upstream of the filtration means for performing solid-liquid separation on the water to which the coagulant has been added from the addition means.
(Additional Note 9) An image processing unit that digitizes the state of the flocculant based on an image of the flocculant in the water to which the flocculant is added from the adding means;
A control device having a control unit that controls the amount of flocculant added by the addition means based on the state of the flocculant quantified by the image processing unit, and at least one of the inlet pressure of a filtration means that filters the water to which the flocculant has been added, the filtration flow rate of the filtration means, and the water level in the filtration means.
(Appendix 10) A process of quantifying the state of the flocculants based on an image of the flocculants in the water to which the flocculant has been added from the adding means;
A process of acquiring at least one of a pressure at an inlet of a filtering means for filtering the water to which the coagulant has been added, a filtration flow rate of the filtering means, and a water level in the filtering means;
and controlling the amount of the flocculant added by the adding means based on the quantified state of the flocculants and the acquired value.
(Appendix 11) A computer includes:
A step of quantifying the state of the flocculants based on an image of the state of the flocculants in the water to which the flocculant has been added from the adding means;
A step of acquiring at least one of a pressure at an inlet of a filtering means for filtering the water to which the coagulant has been added, a filtration flow rate of the filtering means, and a water level in the filtering means;
A program for executing a procedure for controlling the amount of flocculant added by the addition means based on the quantified state of the flocculant and the acquired value.

REFERENCE SIGNS LIST 100 Reaction tank 101 Agitator 110 Relay tank 120 Raw water tank 130 Coagulation tank 140 Flotation tank 150 Treated water tank 200, 210 Pump 300 Filtration membrane 301, 302 Sand filtration device 410, 420 Pressure sensor 430 Water level gauge 440 Flow meter 500 Imaging device 600, 601 Control device 610 Image processing unit 620, 621 Control unit 700 Addition device 710 Coagulant storage tank 800 Agitation device

Claims (11)

An adding means for adding a flocculant to the water to be treated;
an imaging means for imaging a state of the flocculant in the water to which the flocculant has been added from the adding means;
A filtering means for filtering the water to which the flocculant has been added from the adding means;
A measuring means for measuring at least one of a pressure at an inlet of the filtering means, a filtering flow rate of the filtering means, and a water level in the filtering means;
A water treatment system having a control means for controlling the amount of flocculant added by the addition means based on the state of the flocculant imaged by the imaging means and the value measured by the measurement means. 2. The water treatment system according to claim 1,
The control means calculates a characteristic quantity representing the state of the aggregate from the image captured by the imaging means. 3. The water treatment system according to claim 2,
The control means calculates the feature amount based on the number of edge pixels of the aggregate. In the water treatment system according to any one of claims 1 to 3,
The control means controls a lower limit of the amount of the flocculant added by the adding means based on the amount of change in the value measured by the measuring means. In the water treatment system according to any one of claims 1 to 3,
The water treatment system, wherein the adding means adds an inorganic flocculant as the flocculant. In the water treatment system according to any one of claims 1 to 3,
A water tank into which the water to be treated flows,
The adding means is a water treatment system that adds the coagulant to the water to be treated that has flowed into the water tank. In the water treatment system according to any one of claims 1 to 3,
A backwashing means for backwashing the filtering means,
The control means controls the lower limit of the amount of coagulant added by the addition means based on the change in the value measured by the measurement means before and after backwashing the filtration means using the backwashing means. In the water treatment system according to any one of claims 1 to 3,
The water treatment system further comprises a solid-liquid separation means, which is disposed upstream of the filtering means and performs solid-liquid separation on the water to which the flocculant has been added by the adding means. an image processing unit that quantifies the state of the flocculants based on an image of the flocculants in the water to which the flocculant has been added from the adding means;
A control device having a control unit that controls the amount of flocculant added by the addition means based on the state of the flocculant quantified by the image processing unit, and at least one of the inlet pressure of a filtration means that filters the water to which the flocculant has been added, the filtration flow rate of the filtration means, and the water level in the filtration means. A process of quantifying the state of the flocculants based on an image of the state of the flocculants in the water to which the flocculant has been added from the adding means;
A process of acquiring at least one of a pressure at an inlet of a filtering means for filtering the water to which the coagulant has been added, a filtration flow rate of the filtering means, and a water level in the filtering means;
and controlling the amount of the flocculant added by the adding means based on the quantified state of the flocculants and the acquired value. On the computer,
A step of quantifying the state of the flocculants based on an image of the state of the flocculants in the water to which the flocculant has been added from the adding means;
A step of acquiring at least one of a pressure at an inlet of a filtering means for filtering the water to which the coagulant has been added, a filtration flow rate of the filtering means, and a water level in the filtering means;
A program for executing a procedure for controlling the amount of flocculant added by the addition means based on the quantified state of the flocculant and the acquired value.

Images