JP7195809B2 - Controller and solid-liquid separation system - Google Patents

Description

Embodiments of the present invention relate to controllers and solid-liquid separation systems.

Solid-liquid separation treatment is one of methods for purifying water to be treated such as waste water and sludge. In wastewater treatment, solid-liquid separation is performed as a pretreatment, and the separated solids and wastewater are treated by appropriate methods, thereby reducing treatment costs. In sludge treatment, solid-liquid separation treatment is performed as dehydration treatment of sludge, and by reducing the volume of sludge, the cost required for transportation and disposal can be reduced. In such a solid-liquid separation process, a polymer flocculant may be injected into the water to be treated in order to improve solid-liquid separation performance. The polymer flocculant has the effect of flocculating solids in the water to be treated, and has the effect of increasing the sedimentation property of the solids, thus contributing to the improvement of solid-liquid separation performance.

On the other hand, if the injection amount of the polymer flocculant is insufficient, the solid-liquid separation performance will decrease, and if the injection amount is too large, a large amount of the polymer flocculant will remain in the water to be treated, resulting in deterioration of the treated water. Therefore, the injection amount of the polymer flocculant must be appropriately adjusted according to the fluctuation of the amount of solid matter in the water to be treated. In addition, in solid-liquid separation treatment, it is common to dissolve a polymer flocculant, which is often distributed in granular form, in water and inject it into the water to be treated. The performance of solid-liquid separation may decrease depending on the properties of the molecular solution. Due to such a background, conventionally, solid-liquid separation performance sometimes deteriorated due to the properties and injection amount of the polymer flocculant injected into the water to be treated.

JP 2015-57288 A JP 2011-167651 A Japanese Patent Application Laid-Open No. 2004-202400

Gehr, Ronald & Kalluri, Ramesh. (1983). EFFECTS OF SHORT-TERM STORAGE AND ELEVATED TEMPERATURES ON THE FLOCCULATION ACTIVITY OF AQUEOUS POLYMER SOLUTIONS. Water pollution research journal of Canada.

A problem to be solved by the present invention is to provide a control device and a solid-liquid separation system capable of suppressing deterioration in solid-liquid separation performance of water to be treated.

The control device of the embodiment mixes a reforming device that removes residual chlorine components from the dilution water by activated carbon treatment, a polymer flocculant, and the dilution water from which the residual chlorine components have been removed to prepare a polymer solution. a dissolution tank, a flocculation tank in which the polymer solution prepared in the dissolution tank is injected into the water to be treated to flocculate the solids in the water, and the water to be treated in which the solids are flocculated is mixed with the solids and moisture. and a water quality meter for measuring the residual chlorine concentration of the dilution water from which the residual chlorine component has been removed . The controller controls the operation of the reformer based on the residual chlorine concentration measured by the water quality meter .

The figure which shows the structural example of the conventional solid-liquid separation system. The figure which shows the structural example of the solid-liquid separation system of 1st Embodiment. FIG. 2 is a diagram showing a specific example of the functional configuration of a control device according to the first embodiment; The figure which shows the structural example of the solid-liquid separation system of 2nd Embodiment. The figure which shows the specific example of the functional structure of the control apparatus in 2nd Embodiment. The figure which shows the structural example of the solid-liquid separation system of 3rd Embodiment. The figure which shows the specific example of the functional structure of the control apparatus in 3rd Embodiment.

Hereinafter, a control device and a solid-liquid separation system according to embodiments will be described with reference to the drawings.

(outline)
FIG. 1 is a diagram showing a configuration example of a conventional solid-liquid separation system. A solid-liquid separation system 90 includes a dissolution tank 91 , a first stirrer 92 , a polymer solution injection pump 93 (an example of an injection device), an aggregation tank 94 , a second stirrer 95 and a solid-liquid separation device 96 . The dissolution tank 91 dissolves the granular polymer flocculant in water (hereinafter referred to as "dilution water") as a solvent to prepare an aqueous solution of the polymer flocculant (hereinafter referred to as "polymer solution"). water tank. The first stirrer 92 is a device that stirs the polymer flocculant and the dilution water introduced into the dissolving tank 91 . The polymer solution injection pump 93 is a device for injecting the polymer solution prepared in the dissolving tank 91 into the aggregation tank 94 . The coagulation tank 94 is a tank for mixing the polymer solution and the water to be treated to coagulate solids in the water to be treated. The second stirrer 95 is a device for stirring to mix the polymer solution and the water to be treated. The solid-liquid separation device 96 is a device that separates the water to be treated in which the solids have aggregated into solids and water.

Here, the polymer solution injection pump 93 is configured to operate at an injection rate determined based on the results of a simulation test of solid-liquid separation conducted in laboratory L (hereinafter referred to as "set injection rate"). be done. Basically, the set injection rate is determined based on the test results showing good solid-liquid separation performance. The injection rate is not always optimal at the time of setting. If the set injection rate is smaller than the optimum injection rate, the solid-liquid separation performance is lowered, and the water to be treated cannot be separated into desired properties of water and solids. Also, if the injection rate is higher than the optimum injection rate, the solid-liquid separation performance is also lowered. In addition, since the injection amount of the polymer flocculant increases, the chemical cost also increases. Furthermore, a large amount of the polymer flocculant will remain in the water, and there is a concern that the quality of the treated water will deteriorate.

Further, when a polymer solution is prepared by stirring a polymer flocculant and diluent water, it may take time to uniformly dissolve the polymer flocculant due to generation of lumps and the like. For this reason, if an attempt is made to lengthen the stirring time, the capacity of the dissolving tank 91 must be increased accordingly, resulting in an increase in the size of the apparatus. An increase in the size of the device leads to a rise in the cost of the device and also makes it difficult to secure a setting place. Furthermore, conventionally, since there was no means for detecting the dissolution state of the polymer flocculant, a non-uniform dissolution state of the polymer solution was injected, and there were cases where desirable solid-liquid separation performance could not be obtained.

In addition, it is known that properties of a polymer solution, which are desirable for solid-liquid separation performance, deteriorate depending on the retention time and retention environment. However, conventionally, since there was no means for preventing or detecting deterioration of the properties, there were cases where the actual injection rate was less than the optimum injection rate, and desired solid-liquid separation performance could not be obtained.

(First embodiment)
FIG. 2 is a diagram showing a configuration example of the solid-liquid separation system of the first embodiment. A solid-liquid separation system 100 of the first embodiment includes a dissolution tank 1 , a polymer solution injection pump 2 , a coagulation tank 3 , a solid-liquid separator 4 and a controller 5 . The dissolution tank 1 dissolves a granular polymer flocculant in water (hereinafter referred to as "dilution water") as a solvent to prepare an aqueous solution of the polymer flocculant (hereinafter referred to as "polymer solution"). water tank. The dissolving tank 1 is equipped with a first stirrer 11 for stirring the polymer solution.

Further, the dissolution tank 1 is equipped with a water quality meter 12 for measuring water quality (hereinafter referred to as "concentration index") that correlates with the concentration of the polymer flocculant in the polymer solution (hereinafter referred to as "flocculant concentration"). be done. The water quality meter 12 measures at least one of UV-VIS (Ultra Violet-Visible) absorbance, colloidal charge, and streaming current value of the polymer solution. The water quality meter 12 is communicably connected to the control device 5 and transmits measurement data to the control device 5 .

The polymer solution injection pump 2 is a device for injecting the polymer solution prepared in the dissolving tank 1 into the aggregation tank 3 . Polymer solution injection pump 2 is communicably connected to controller 5 . The polymer solution injection pump 2 injects the polymer solution based on the injection rate notified from the controller 5 .

The coagulation tank 3 is a tank for mixing the polymer solution injected by the polymer solution injection pump 2 and the water to be treated to coagulate solids in the water to be treated. The aggregation tank 3 is equipped with a second stirrer 31 for stirring the mixed water of the polymer solution and the water to be treated. In the preceding stage of the flocculation tank 3, a flow meter 32 for measuring the flow rate of the water to be treated flowing into the tank, a solid concentration meter 33 to measure the solid concentration of the water to be treated flowing into the tank, is provided. The flowmeter 32 and solid concentration meter 33 are communicably connected to the control device 5 and transmit measurement data to the control device 5 .

The solid-liquid separation device 4 is a device that separates the water to be treated (mixed water) in which the solids are aggregated by injecting the polymer solution into solids and water.

The control device 5 has a function of adjusting the injection amount of the polymer solution to be injected into the coagulation tank 3 according to the coagulant concentration of the polymer solution prepared in the dissolving tank 1 . Specifically, the control device 5 determines the injection rate of the polymer solution injection pump 2 based on the concentration index value measured by the water quality meter 12 .

FIG. 3 is a diagram illustrating a specific example of the functional configuration of the control device according to the first embodiment; The control device 5 in the first embodiment includes a CPU (Central Processing Unit), a memory, an auxiliary storage device, and the like connected via a bus, and executes programs. The control device 5 functions as a device including a communication section 51, a storage section 52, a measurement data acquisition section 53, and an injection rate control section 54 by executing a program. All or part of each function of the control device 5 may be implemented using hardware such as an ASIC (Application Specific Integrated Circuit), a PLD (Programmable Logic Device), or an FPGA (Field Programmable Gate Array). The program may be recorded on a computer-readable recording medium. Computer-readable recording media include portable media such as flexible disks, magneto-optical disks, ROMs and CD-ROMs, and storage devices such as hard disks incorporated in computer systems. The program may be transmitted over telecommunications lines.

A communication unit 51 is a communication interface. The communication unit 51 may be a wired communication interface or a wireless communication interface. The communication unit 51 is communicably connected to the water quality meter 12, the polymer solution injection pump 2, the flow meter 32, and the solid matter concentration meter 33.

The storage unit 52 is configured using a storage device such as a magnetic hard disk device or a semiconductor storage device. The storage unit 52 stores the measurement data of the water quality meter 12 , the flow meter 32 and the solid matter concentration meter 33 . Further, the storage unit 52 pre-stores relationship information indicating the relationship between the concentration index value of the polymer solution and the concentration of the coagulant.

The measurement data acquisition unit 53 acquires measurement data from the water quality meter 12 , the flow meter 32 and the solid matter concentration meter 33 via the communication unit 51 . The measurement data acquisition unit 53 stores the acquired measurement data in the storage unit 52 .

The injection rate control section 54 has a function of controlling the injection rate of the polymer solution injection pump 2 . Specifically, the injection rate control unit 54 determines the injection rate of the polymer solution injection pump 2 according to the coagulant concentration of the polymer solution prepared in the dissolution tank 1, and sends the determined injection rate to the communication unit 51. to the polymer solution injection pump 2 via.

More specifically, the relationship information generated by the following procedure example is recorded in the storage unit 52 in advance.
[Procedure 1] A plurality of patterns of polymer solutions having different mixing ratios of polymer flocculant and pure water are prepared.
[Procedure 2] The concentration index value of the polymer solution of each pattern prepared in Procedure 1 is measured.
[Procedure 3] The concentration index value measured in Procedure 2 and the coagulant concentration calculated from the mixture ratio are associated with each pattern.

The injection rate control unit 54 controls the concentration index value of the polymer solution stored in the dissolution tank 1 based on the relationship information thus generated and the measurement data of the concentration index value of the polymer solution acquired during the solid-liquid separation process. Estimate the concentration of the flocculant in the polymer solution. On the other hand, the amount of polymer flocculant required for flocculating solids is determined according to the amount of solids contained in the water to be treated. Therefore, the injection rate control unit 54 determines the injection rate of the polymer solution injection pump 2 based on the estimated coagulant concentration and the flow rate and solid concentration of the water to be treated indicated by the measurement data.

Here, the UV-VIS absorbance, colloid charge amount, or streaming current value of the polymer solution can be used as the concentration index value of the polymer solution. The injection rate control unit 54 may determine the injection rate based on one of these concentration index values measured, or may determine the injection rate based on a plurality of measured values. For example, when the injection rate is determined based on a plurality of concentration index values, the injection rate control unit 54 determines an average injection rate obtained for each of the plurality of concentration index values as the actual injection rate. Alternatively, instead of the relationship information for each concentration index, the injection rate may be determined using relationship information indicating a correspondence relationship between a plurality of concentration index values and coagulant concentrations.

According to the solid-liquid separation system 100 of the first embodiment configured as described above, the injection amount of the polymer flocculant to the water to be treated is changed by the fluctuation of the water quality of the inflowing water to be treated or the concentration of the polymer solution. Since it becomes possible to adjust according to fluctuations in the concentration of the coagulant, it is possible to suppress deterioration in solid-liquid separation performance of the water to be treated.

(Second embodiment)
FIG. 4 is a diagram showing a configuration example of the solid-liquid separation system of the second embodiment. The solid-liquid separation system 100a of the second embodiment is similar to the solid-liquid separation system of the first embodiment in that it does not include the flow meter 32 and the solid concentration meter 33 and includes a controller 5a instead of the controller 5. Different from 100. Further, the control device 5a is different from the control device 5 in the first embodiment in that instead of controlling the injection rate of the polymer solution injection pump 2, the control device 5a performs control to switch the operating state of the polymer solution injection pump 2. . Since other configurations are the same as those of the first embodiment, the same configurations in FIG. 4 are denoted by the same reference numerals as those in FIG.

FIG. 5 is a diagram showing a specific example of the functional configuration of the control device according to the second embodiment. The control device 5a in the second embodiment includes a storage unit 52a instead of the storage unit 52, a measurement data acquisition unit 53a instead of the measurement data acquisition unit 53, and operates instead of the injection rate control unit 54. It differs from the control device 5 in the first embodiment in that it includes a state control section 55 . Since other configurations are the same as those of the first embodiment, the same configurations in FIG. 5 are denoted by the same reference numerals as in FIG.

The storage unit 52a differs from the storage unit 52 in the first embodiment in that the determination information is stored in advance instead of the relationship information. The determination information is information indicating conditions for determining the dissolution state of the polymer flocculant in the dissolving tank 1 . Here, as an example, it is assumed that the threshold value of the index value indicating the dissolution state of the polymer flocculant is stored in advance in the storage unit 52a as the determination information.

While the measurement data acquisition unit 53 in the first embodiment acquires the measurement data of the water quality meter 12, the flow meter 32, and the solid matter concentration meter 33, the measurement data acquisition unit 53a acquires only the measurement data of the water quality meter 12. is different from the measurement data acquisition unit 53 in the first embodiment in that it acquires .

The operating state control unit 55 has a function of switching the operating state of the polymer solution injection pump 2 according to the solution state of the polymer coagulant in the dissolving tank 1 . Here, the polymer solution injection pump 2 is in a state in which the polymer solution can be injected (hereinafter referred to as an “injectable state”) and a state in which the polymer solution injection operation is inhibited (hereinafter referred to as an “injectable state”). (referred to as an "injection inhibited state"). The operating state control unit 55 observes changes in the dissolution state of the polymer flocculant based on the time-series measurement data acquired by the water quality meter 12, and it is observed that the polymer flocculant has dissolved uniformly to some extent. At the timing, the operating state of the polymer solution injection pump 2 is changed from the injection inhibited state to the injection enabled state.

In general, the degree of change in the concentration of the coagulant in the polymer solution becomes smaller as the dissolution state of the polymer coagulant approaches uniformity. , the magnitude of the change in the dissolution state of the polymer flocculant can be observed. Specifically, the operating state control unit 55 calculates the dispersion value of the concentration index value in a past predetermined period based on the measurement data of the water quality meter 12, and observes the change in the dispersion value to detect the polymer aggregation. Observe the change in the dissolution state of the agent. In this case, the dispersion value indicates a smaller value as the polymer flocculant is dissolved more uniformly. The operating state of is changed from the injection inhibited state to the injection enabled state. In this case, the storage unit 52a preliminarily stores a threshold used for determining the variance value as determination information.

Note that the operating state control unit 55 may determine the dissolution state based on any one measurement value of the UV-VIS absorbance, colloidal charge amount, and flowing current value of the polymer solution, or may determine the dissolution state based on a plurality of measurements. The dissolved state may be determined based on the value. For example, when determining the dissolution state based on a plurality of measured values, the operating state control unit 55 changes the operating state of the polymer solution injection pump 2 when all the variance values of the concentration index values are equal to or less than the threshold. Alternatively, the operating state of the polymer solution injection pump 2 may be changed when a part of the dispersion values becomes equal to or less than the threshold value. Further, for example, the operating state control unit 55 calculates an index value of the dissolved state based on each dispersion value, and changes the operating state of the polymer solution injection pump 2 when the index value becomes equal to or less than a threshold value. good too.

According to the solid-liquid separation system 100a of the second embodiment configured as described above, since the polymer solution in which the polymer flocculant is sufficiently uniformly dissolved is injected into the water to be treated, the solidity of the water to be treated is reduced. A decrease in liquid separation performance can be suppressed.

(Third embodiment)
FIG. 6 is a diagram showing a configuration example of a solid-liquid separation system according to the third embodiment. The solid-liquid separation system 100b of the third embodiment does not include the water quality meter 12, the flow meter 32, and the solid concentration meter 33, includes the controller 5b instead of the controller 5, the reformer 6, the dilution It differs from the solid-liquid separation system 100 of the first embodiment in that it further includes a water injection pump 7 and a water quality meter 71 . In addition, the control device 5b performs control to switch the operation states of the reformer 6 and the dilution water injection pump 7 instead of controlling the injection rate of the polymer solution injection pump 2, which is similar to the control in the first embodiment. Differs from device 5. Since other configurations are the same as those of the first embodiment, in FIG. 6, similar configurations are denoted by the same reference numerals as in FIG.

The reformer 6 is a device for reforming the dilution water used for preparing the polymer solution. Specifically, the reformer 6 reforms the dilution water by removing a predetermined component from the dilution water (hereinafter referred to as "reformation process"). For example, the reforming treatment is realized by one or both of membrane treatment (for example, reverse osmosis membrane treatment) and activated carbon treatment. The operation of the reformer 6 is controlled by the controller 5b.

The dilution water injection pump 7 is a device for supplying the dilution water reformed by the reformer 6 (hereinafter referred to as “modified dilution water”) to the dissolution tank 1 . The operation of the dilution water injection pump 7 is controlled by the controller 5b. A water quality meter 71 for measuring the quality of the reformed dilution water is installed upstream of the dilution water injection pump 7 . Specifically, the water quality meter 71 measures part or all of the calcium concentration, residual chlorine concentration, and electrical conductivity as the water quality of the reformed dilution water. The water quality meter 71 is communicably connected to the control device 5b and transmits measurement data to the control device 5b. Note that the dilution water injection pump 7 may be configured as part of the reformer 6 .

FIG. 7 is a diagram showing a specific example of the functional configuration of the control device according to the third embodiment. The control device 5b in the third embodiment includes a storage unit 52b instead of the storage unit 52, a measurement data acquisition unit 53b instead of the measurement data acquisition unit 53, and operates instead of the injection rate control unit 54. It differs from the control device 5 in the first embodiment in that it includes a state control section 55b. Since other configurations are the same as those of the first embodiment, the same configurations in FIG. 7 are denoted by the same reference numerals as those in FIG.

The storage unit 52b differs from the storage unit 52 in the first embodiment in that determination information is stored in advance instead of relationship information. The judgment information is information indicating conditions for judging the quality of the reformed dilution water. Here, as an example, it is assumed that the threshold value of the index value of the quality of the reformed dilution water is stored in advance in the storage unit 52b as the determination information. Moreover, below, in order to distinguish from the determination information in 2nd Embodiment, the determination information in 3rd Embodiment is called 2nd determination information.

The measurement data acquisition unit 53b differs from the measurement data acquisition unit 53 in the first embodiment in that it acquires the measurement data of the water quality meter 71 instead of the measurement data of the water quality meter 12, the flow meter 32, and the solid matter concentration meter 33. .

The operation state control unit 55b has a function of switching the operation state of the reformer 6 or the dilution water injection pump 7 according to the quality of the reformed dilution water. Here, the reformer 6 is in a state in which the reforming process can be executed (hereinafter referred to as "executable state") and a state in which the reforming process is inhibited (hereinafter referred to as "execution inhibited state"). and can take two operating states. Similarly, the dilution water injection pump 7 is in a state in which the reformed dilution water can be injected (hereinafter referred to as an “injectable state”) and a state in which the reformed dilution water injection operation is inhibited (hereinafter referred to as “injectable state”). hereinafter referred to as an "injection inhibited state").

Generally, it is known that the deterioration of the solid-liquid separation performance of the water to be treated is caused by a predetermined component (hereinafter referred to as "factor component") present in the dilution water. Specifically, it is known that the factor components are residual chlorine components and ion components. In particular, among ionic components, divalent ions such as calcium ions, magnesium ions and sulfate ions are said to contribute to the deterioration of the solid-liquid separation performance. Among these factor components, the residual chlorine component can be removed by activated carbon treatment, and the ion component can be removed by membrane treatment. However, it is known that the removal performance of factor components by such a modification treatment generally decreases as the treatment amount increases. Therefore, when the reforming process is functioning well, the concentration of the factor component in the reformed dilution water is observed at a low value, but as the performance deterioration of the reforming process progresses, a higher value is observed. become.

Therefore, the operating state control unit 55b observes the change in water quality caused by the factor component in the reformed dilution water based on the measurement data acquired in time series by the water quality meter 71, and the concentration of the factor component exceeds a predetermined threshold value. At the timing when it is observed, the operating state of the reformer 6 is changed from the executable state to the execution inhibited state, or the operating state of the dilution water injection pump 7 is changed from the injection possible state to the injection inhibited state . . Since the ion concentration of the factor components correlates with the conductivity of the reformed dilution water, the operation state control unit 55b controls the reformer 6 or the operation of the dilution water injection pump 7 may be controlled.

According to the solid-liquid separation system 100b of the third embodiment configured as described above, dilution water having a low factor component concentration can be used for preparation of the polymer solution. Decrease can be suppressed.

(Modification)
In addition to the injection rate control unit 54, the control device 5 of the first embodiment includes either one or both of the operation state control unit 55 in the second embodiment and the operation state control unit 55b in the third embodiment. It may be configured as

According to at least one embodiment described above, the polymer solution preparation process is controlled based on the quality of the dilution water, or the polymer solution injection process into the water to be treated is controlled based on the water quality of the polymer solution. By having a control device that and a solid-liquid separation device for separating the water in which the solids have aggregated into solids and water, thereby suppressing deterioration in solid-liquid separation performance. can be done.

While several embodiments of the invention have been described, these embodiments have been presented by way of example and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, replacements, and modifications can be made without departing from the scope of the invention. These embodiments and their modifications are included in the scope and spirit of the invention, as well as the scope of the invention described in the claims and equivalents thereof.

DESCRIPTION OF SYMBOLS 100,100a,100b... Solid-liquid separation system 1... Dissolution tank 11... 1st stirrer 12... Water quality meter 2... Polymer solution injection pump 3... Aggregation tank 31... 2nd stirrer 32... Flow rate Meter 33 Solid concentration meter 4 Solid-liquid separator 5, 5a, 5b Control device 51 Communication unit 52, 52a, 52b Storage unit 53, 53a, 53b Measurement data acquisition unit, 54... Injection rate control unit 55, 55b... Operation state control unit 6... Reformer 7... Dilution water injection pump 71... Water quality meter 90... Conventional solid-liquid separation system 91... Dissolution tank 92... First stirrer 93 Polymer solution injection pump 94 Aggregation tank 95 Second stirrer 96 Solid-liquid separator

Claims (7)

A reforming device for removing residual chlorine components from dilution water by activated carbon treatment, a dissolution tank for preparing a polymer solution by mixing a polymer flocculant and the dilution water from which the residual chlorine components have been removed, and the dissolution tank. A flocculation tank for injecting the polymer solution prepared in the above into the water to be treated to flocculate solids in the water to be treated, and a solid-liquid separation device for separating the water to be treated in which the solids are flocculated into solids and water. and a water quality meter that measures the residual chlorine concentration of the dilution water from which the residual chlorine component has been removed , wherein
controlling the operation of the reformer based on the residual chlorine concentration measured by the water quality meter ;
Control device. When the residual chlorine concentration is equal to or higher than a predetermined threshold, the reformer suppresses the operation of reforming the dilution water or the operation of supplying the reformed dilution water to the dissolution tank.
A control device according to claim 1 . The reformer further removes divalent ion components in the diluted water by reverse osmosis membrane treatment,
The water quality meter further measures the divalent ion concentration or conductivity of the diluted water from which the divalent ion component has been removed,
Controlling the operation of the reformer based on the divalent ion concentration or conductivity of the dilution water reformed by the reformer;
3. A control device according to claim 1 or 2 . The divalent ion component is a sulfate ion, a calcium ion or a magnesium ion,
4. A control device according to claim 3 . When the divalent ion concentration or conductivity is equal to or higher than a predetermined threshold, the reformer suppresses the operation of reforming the dilution water or the operation of supplying the reformed dilution water to the dissolution tank.
5. A control device according to claim 3 or 4 . a reformer that removes residual chlorine components from the dilution water by activated carbon treatment;
a dissolution tank for preparing a polymer solution by mixing a polymer flocculant and diluting water from which the residual chlorine component has been removed;
a flocculating tank for injecting the polymer solution prepared in the dissolving tank into the water to be treated to flocculate solids in the water;
a solid-liquid separation device for separating the water to be treated in which the solids have aggregated into solids and water;
a water quality meter that measures the residual chlorine concentration of the dilution water from which the residual chlorine component has been removed;
a control device for controlling the operation of the reformer based on the residual chlorine concentration measured by the water quality meter ;
A solid-liquid separation system comprising: When the residual chlorine concentration is equal to or higher than a predetermined threshold, the control device suppresses the operation of the reformer reforming the dilution water or the operation of supplying the reformed dilution water to the dissolution tank.
The solid-liquid separation system according to claim 6.

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