JP7225389B2 - water treatment system - Google Patents

Description

Embodiments of the present invention relate to water treatment systems that purify organic wastewater, such as sewage, agricultural wastewater, and industrial wastewater, with microorganisms.

2. Description of the Related Art In water treatment systems for purifying organic wastewater containing organic matter such as sewage, biological treatment using microorganisms (hereinafter referred to as “microbial treatment”) is generally used. As one of the water treatment systems utilizing this type of microbial treatment, there is a water treatment system using the rotating disk method.

In the rotating disk method, useful microorganisms such as Bacillus spp. (hereinafter simply referred to as "microorganisms") is arranged to make it easier to predominantly adhere to the fibrous contact body, and the disc-shaped flat plate is rotated using power such as a motor, and the contact body In this method, organic substances and nitrogen components in the raw water are removed by the action of the microorganisms by bringing the raw water into contact with microorganisms such as Bacillus that adhere to the surface.

By making Bacillus dominant, the amount of excess sludge generated in the water treatment process can be reduced, the generation of odor can be suppressed, and good organic matter and nitrogen removal performance can be obtained. As described above, when the biological reactor for the activated sludge process is placed in the latter stage, the load on the biological reactor can be reduced, so the power consumption of the blower in the biological reactor can be greatly reduced. Are known.

On the other hand, when microorganisms adhere excessively to the disk-shaped flat plate, oxygen cannot be sufficiently supplied to the microorganisms, resulting in deterioration of purification performance. Therefore, a washing operation is required to remove the microorganisms excessively attached to the flat plate by peeling or the like.

Conventionally, whether or not this cleaning operation is necessary is determined based on the results of periodic inspections by an operator. That is, the operator periodically visually inspects the disk-shaped flat plate, and if he finds that the flat plate has excessively adhered microorganisms, a washing operation is carried out to remove the excess microorganisms from the disk-shaped flat plate. It is removed by peeling or the like.

Japanese Patent Application Laid-Open No. 2009-166038 Japanese Patent Application Laid-Open No. 2007-301511 Japanese Patent Application Laid-Open No. 2000-189991

However, due to the recent demands for lower maintenance and management costs, labor saving, and more efficient operation of water treatment systems, there is a growing need for automatic operation that eliminates human work as much as possible.

The problem to be solved by the present invention is to estimate the amount of microorganisms adhering to a flat plate from information from a non-contact sensor, and to automatically control the water treatment operation based on the estimation result. It is to provide a system .

The water treatment system of the embodiment is a water treatment system that purifies raw water with microorganisms while rotating a flat plate on which microorganisms are attached so that a part of it is immersed in raw water, and rotates a shaft to which the flat plate is attached. a motor, a measurement unit for measuring information for estimating the amount of microorganisms adhering to the flat plate, and a motor rotating at a first rotation speed or higher than the first rotation speed for peeling off the microorganisms adhering to the flat plate. and a controller that controls to rotate at a number of revolutions of 2. Based on the information measured by the measuring unit, the controller estimates the amount of microorganisms adhering to the flat plate, determines whether the estimated amount of microorganisms has reached a predetermined value, and determines that the predetermined value has been reached, The motor is controlled to rotate at the second rotation speed, and when it is determined that the predetermined value has not been reached, the motor is controlled to rotate at the first rotation speed.

FIG. 1 is a conceptual diagram showing a configuration example of a water treatment system to which the water treatment method of the first embodiment is applied. FIG. 2 is a conceptual diagram showing a partial configuration example of the water treatment system of the first embodiment, including a configuration example of the rotating disk device viewed from the front side (raw water introduction side in FIG. 1). FIG. 3 is a block diagram showing a configuration example of a controller and a monitoring device in the water treatment system of the first embodiment. FIG. 4 is a diagram illustrating the relationship between the amount of microorganisms adhering to the rotating disc and the motor current value obtained when the rotating disc rotates when the number of rotations per unit time is the same. FIG. 5 is a block diagram showing a configuration example of a controller and a monitoring device in Modification 2 of the first embodiment. FIG. 6 is a graph illustrating the relationship between the number of revolutions per unit time of the rotating disk and the current value measured by the ammeter during rotation of the rotating disk. FIG. 7 is a conceptual diagram showing a partial configuration example of a water treatment system according to Modification 3 of the first embodiment, and shows a state in which the rotating disk device is viewed from the front side (raw water introduction side in FIG. 1). FIG. 4 is a diagram illustrating an example; FIG. 8 is a conceptual diagram showing a configuration example of a water treatment system to which the water treatment method of the second embodiment is applied. FIG. 9 is a conceptual diagram showing a partial configuration example of the water treatment system of the second embodiment, including a configuration example of the rotating disk device viewed from the front side (raw water introduction side in FIG. 8). FIG. 10 is a block diagram showing a configuration example of a controller and a monitoring device in the water treatment system of the second embodiment. FIG. 11 is a conceptual diagram showing a partial configuration example of a water treatment system including a configuration example of a rotating disk device in the water treatment system of Modification 1 of the second embodiment. FIG. 12 is a conceptual diagram showing a partial configuration example of a water treatment system including a configuration example of a rotating disk device according to modification 2 of the second embodiment. FIG. 13 is a block diagram showing a configuration example of a controller and a monitoring device in a water treatment system according to modification 3 of the second embodiment. FIG. 14 is a conceptual diagram showing a configuration example of a water treatment system to which the water treatment method of the third embodiment is applied. FIG. 15 is a block diagram showing a configuration example of a controller and a monitoring device in the water treatment system of the third embodiment. FIG. 16 is a diagram for explaining adhesion amount control of microorganisms by a water treatment system to which the water treatment method of the third embodiment is applied. FIG. 17 is a conceptual diagram showing a configuration example of a water treatment system to which the water treatment method of the fourth embodiment is applied. FIG. 18 is a block diagram showing a configuration example of a controller and monitoring device in the water treatment system of the fourth embodiment. FIG. 19 is a diagram for explaining the relationship between the adhesion amount of microorganisms adhering to a flat plate and the amount of sludge returned. FIG. 20 is a conceptual diagram showing a configuration example of a water treatment system of modification 2 of the fourth embodiment. FIG. 21 is a block diagram showing a configuration example of a controller and a monitoring device in a water treatment system of modification 2 of the fourth embodiment. FIG. 22 is a conceptual diagram showing a configuration example of a water treatment system to which the water treatment method of the fifth embodiment is applied. FIG. 23 is a block diagram showing a configuration example of a controller and a monitoring device in the water treatment system of the fifth embodiment. FIG. 24 is a diagram illustrating the general relationship between energy and frequency of sound waves received by a sound wave receiver. FIG. 25 is a diagram illustrating another relationship between energy and frequency of sound waves received by a sound wave receiver. FIG. 26 is a partial side view of a rotating disk device showing an arrangement example in which four detection units are arranged in one gap. FIG. 27 is a conceptual diagram showing another configuration example of the rotary disk device shown in FIG. 26 viewed from the front side (left side in FIG. 26). FIG. 28 is a conceptual diagram showing another configuration example of the rotating disk device shown in FIG. 22 viewed from the front side (left side in FIG. 22). FIG. 29 is a block diagram showing a configuration example of a controller and a monitoring device in a water treatment system of modification 2 of the fifth embodiment. FIG. 30 is a block diagram showing a configuration example of a controller and a monitoring device in a water treatment system of modification 4 of the fifth embodiment. FIG. 31 is a conceptual diagram showing another configuration example of the rotating disk device according to Modification 4 of the fifth embodiment, viewed from the front side (the left side in FIG. 22). FIG. 32 is a conceptual diagram showing a configuration example of a water treatment system to which the water treatment method of the sixth embodiment is applied. FIG. 33 is a block diagram showing a configuration example of a controller and a monitoring device in the water treatment system of the sixth embodiment. FIG. 34 is a conceptual diagram showing a configuration example of a water treatment system to which the water treatment method of the seventh embodiment is applied. FIG. 35 is a block diagram showing a configuration example of the controller and monitoring device in the water treatment system of the seventh embodiment. FIG. 36 is a conceptual diagram showing a configuration example of a water treatment system to which the water treatment method of the eighth embodiment is applied. 37 is a block diagram showing a configuration example of a controller and a monitoring device in the water treatment system of the eighth embodiment; FIG. FIG. 38 is a conceptual diagram showing a configuration example of a water treatment system of modification 2 of the eighth embodiment. FIG. 39 is a block diagram showing a configuration example of a controller and a monitoring device in a water treatment system of modification 2 of the eighth embodiment.

Hereinafter, representative embodiments of the present invention will be described with reference to the drawings. In addition, embodiment of this invention is not limited to the following. Also, in the following description, the same reference numerals are used to denote the same parts as those already described to avoid redundant description.

(First embodiment)
A water treatment system to which the water treatment method of the first embodiment is applied will be described.

FIG. 1 is a conceptual diagram showing a configuration example of a water treatment system to which the water treatment method of the first embodiment is applied.

The water treatment system 100 is a system that purifies raw water w such as sewage, agricultural wastewater, and organic wastewater such as factory wastewater by microbial treatment utilizing microorganisms such as bacillus.

FIG. 1 is a conceptual diagram showing a configuration example of a water treatment system. As illustrated in FIG. 1, the water treatment system 100 includes a rotating disk device 10, a motor 20, an ammeter 25, a controller 40, and a monitoring device 50. FIG. 1 shows a configuration example of the rotating disk device 10 viewed along the flow direction of the raw water w.

The rotating disk device 10 has a water treatment tank 11 . Raw water w is introduced into the water treatment tank 11 from the left side in the drawing. The water treatment tank 11 has a plurality of rotating disk bodies 12 arranged in parallel at regular intervals L inside thereof. The rotating disk 12 can be made of, for example, a porous material.

FIG. 2 is a conceptual diagram showing a partial configuration example of the water treatment system of the first embodiment, including a configuration example of the rotating disk device viewed from the front side (raw water introduction side in FIG. 1).

An upper portion of the water treatment tank 11 may be covered with a housing cover 70 as necessary.

A sludge extraction pipe 60 is connected to the bottom surface of the water treatment tank 11 , and the sludge extraction pipe 60 is provided with a sludge extraction valve 61 .

Each rotating disc member 12 is provided with a through hole around the center of the circle, and is fixed to a shaft 13 inserted into the through hole. As a result, the rotary disk members 12 are arranged parallel to each other with a constant interval L along the long axis direction of the shaft 13 (horizontal direction in FIG. 1, depth direction in FIG. 2).

A contact member 14 is arranged on the end face 12a, which is the surface of each rotating disk 12, to facilitate adherence of microorganisms such as bacillus predominantly. A specific configuration of the contact body 14 is not particularly limited, but a fibrous contact body as disclosed in Patent Document 1 and Patent Document 2 can be used.

The raw water w is introduced into the water treatment tank 11, but each rotating disk 12 is not entirely immersed in the raw water w, but only a lower portion thereof is immersed in the raw water w. It is installed in the water treatment tank 11 so that the part above the part submerged by w is in the gas phase 72 .

As a result, each rotating disk 12 is in contact with the air on its upper side and immersed in the raw water w on its lower side. Such a configuration is achieved, for example, by arranging the shaft 13 horizontally at approximately the same height as the upper edge of the water treatment tank 11 . As a result, even if the water treatment tank 11 is filled with the raw water w, only the lower half of the rotating disk 12 is immersed in the raw water w, so at least the upper half is in contact with the air.

Returning to FIG. 1, the shaft 13 is rotated by the driving force from the motor 20, thereby rotating each rotating disk 12 around the shaft 13 as indicated by the arrow R shown in FIG. That is, each rotating disc body 12 rotates about a center line 15 passing through the center of each rotating disc body 12 and perpendicular to the end surface 12a of each rotating disc body 12 . This rotation speed is, for example, 10 rpm during operation of the water treatment system 100 .

As described above, each rotary disk 12 rotates in the rotation direction R due to the rotation of the shaft 13, so that the microorganisms adhering to the contact body 14 take in oxygen from the air in the gas phase 72, While being immersed in w, organic substances and nitrogen components in raw water w are oxidatively decomposed. As a result, the treated water x from which organic substances and nitrogen components have been removed from the raw water w is discharged from the water treatment tank 11 .

However, with the continuation of such purification operation, the microorganisms adhering to the contact member 14, that is, the surface of the rotating disk member 12, proliferate. Further, as described above, since the rotating disc body 12 can be made of a porous material, microorganisms can enter not only the surface of the rotating disc body 12 but also the inside of the rotating disc body 12 (within the voids). can also adhere.

If the microorganisms adhering to the rotating disc body 12 proliferate excessively, the microorganisms will not be supplied with sufficient oxygen, and the purification performance will be lowered. Furthermore, anaerobic sludge contained in the raw water w may cause adverse effects such as an increase in odor and a decrease in the transparency of the treated water x.

Therefore, it is necessary to manage the rotating disc body 12 so that the microorganisms do not adhere excessively. For this reason, the controller 40 estimates the adhesion amount of microorganisms adhering to the rotating disc body 12, and when it is estimated that the microorganisms are excessively adhering, the rotating disc body 12 The operation of the water treatment system 100 is controlled so that the adherence amount of microorganisms adhering to is kept within an appropriate range.

FIG. 3 is a block diagram showing a configuration example of a controller and a monitoring device in the water treatment system of the first embodiment.

The controller 40 determines the necessity of cleaning the rotary disc 12 based on the adhesion amount estimation unit 41 for estimating the amount of microorganisms attached to the rotary disc 12 and the estimation result of the adhesion amount estimation unit 41 . and a rotation speed switching unit 43 for switching the number of rotations per unit time (for example, one minute) of the rotary disk 12 between normal operation and cleaning.

The monitoring device 50 functions as an interface with the operator of the water treatment system 100, and includes an operating rotation speed setting unit 51, a cleaning rotation speed setting unit 52, and a display unit 53 such as a display.

The operator can set the number of revolutions per unit time c (for example, 10 rpm) of the rotary disk member 12 during normal operation from the operating number of revolutions setting section 51 . Further, the operator can set the rotation speed d (for example, 100 rpm) per unit time of the rotating disk member 12 during washing from the washing rotation speed setting unit 52 . The number of rotations d per unit time of the rotating disk 12 during washing must be 10 times or more that of normal operation because it is necessary to rotate at high speed in order to remove the microorganisms adhering to the rotating disk 12. value.

The operating rotation speed c set in the operating rotation speed setting unit 51 and the cleaning rotation speed d set in the cleaning rotation speed setting unit 52 are output to the rotation speed switching unit 43, and the rotation speed switching unit 43 is retained.

The rotation speed switching unit 43 outputs the operating rotation speed c to the motor 20 unless the cleaning instruction e is output from the cleaning necessity determination unit 42 .

The motor 20 is driven in response to the output of the driving rotation speed c, and rotates the shaft 13 so as to reach the rotation speed (for example, 10 rpm) specified by the driving rotation speed c.

An ammeter 25 is connected to the motor 20 , and the ammeter 25 continuously measures the motor current of the motor 20 during driving and outputs the measured current value a to the adhesion amount estimator 41 .

FIG. 4 is a diagram illustrating the relationship between the amount of microorganisms adhering to the rotating disc and the motor current value obtained when the rotating disc rotates when the number of rotations per unit time is the same.

As the amount of microorganisms adhering to the rotating disc body 12 increases, the torque for rotating the rotating disc body 12 increases. Therefore, as illustrated in FIG. 4, even if the number of rotations per unit time is the same, the current value a measured by the ammeter 25 increases as the amount of adhered microorganisms increases.

Based on the relationship illustrated in FIG. 4, the adhered amount estimator 41 calculates the amount of microorganisms adhering to the rotating disc 12 from the current value a measured by the ammeter 25. 12, the estimated adhesion amount b is output to the display unit 53, and the current value a and the adhesion amount b are output to the cleaning necessity determination unit .

The operator can confirm the adhesion amount b estimated by the adhesion amount estimation unit 41 by displaying it on the display unit 53 .

If the current value a from the adhesion amount estimating unit 41 is higher than the cleaning determination current value shown in FIG. It determines that the rotating disc body 12 needs to be cleaned, and outputs a cleaning command e to the motor 20 and the rotation speed switching unit 43 .

When the cleaning command e is output from the cleaning necessity determination unit 42 , the rotation speed switching unit 43 outputs the cleaning rotation speed d to the motor 20 . As a result, when the cleaning command e is output from the cleaning necessity determination unit 42 , both the cleaning command e and the number of revolutions during cleaning d are output to the motor 20 .

When both the cleaning command e and the cleaning rotation speed d are output to the motor 20, the operation mode is switched from the normal operation to the cleaning process, and the rotation speed of the motor 20 is specified by the operation rotation speed c. The rotation speed is changed from the specified rotation speed to the rotation speed specified by the cleaning rotation speed d (for example, from 10 rpm to 100 rpm), and the shaft 13 is rotated for a predetermined period (several minutes to several tens of minutes).

By such a washing process, the microorganisms excessively adhering to the rotating disc body 12 are separated from the rotating disc body 12 and collected at the bottom of the water treatment tank 11 .

Although it is desirable to stop the introduction of the raw water w into the water treatment tank 11 during the washing process, the washing may be performed while introducing the raw water w without stopping the introduction of the raw water w.

A sludge extraction pipe 60 is connected to the bottom surface of the water treatment tank 11 , and the sludge extraction pipe 60 is provided with a sludge extraction valve 61 .

After completing the cleaning process for a predetermined period, the sludge withdrawal valve 61 is opened. As a result, the microorganisms accumulated at the bottom of the water treatment tank 11 are discharged from the water treatment tank 11 through the sludge extraction pipe 60 . The opening operation of the sludge withdrawal valve 61 is performed after stopping the introduction of the raw water w into the water treatment tank 11 .

After the excess microorganisms are discharged from the water treatment tank 11 in this way, the sludge withdrawal valve 61 is closed, and the introduction of the raw water w into the water treatment tank 11 is resumed, and the cleaning necessity judgment unit 42 Cancel the output of the cleaning command e.

As a result, the rotation speed switching unit 43 outputs the operating rotation speed c to the motor 20, and the operation mode of the water treatment system 100 returns from the washing process to the normal operation. The output of the cleaning command e from the cleaning necessity determination unit 42 may be canceled manually by the operator by inputting a command from the monitoring device 50, or may be interlocked with the closing operation of the sludge removal valve 61. However, it is not limited to this.

As described above, according to the water treatment system 100 of the present embodiment, when the adhesion amount b of microorganisms adhering to the rotating disc body 12 is estimated, and it is determined that the microorganisms are excessively adhered, By switching to the cleaning process, excess microorganisms adhering to the rotating disc body 12 can be removed. As a result, the adherence amount b of microorganisms adhering to the rotating disc body 12 can always be kept within an appropriate range, so that water treatment performance suitable for suppressing odor generation and removing organic substances and nitrogen can be achieved. , can be provided stably and sustainably.

Since such operation is automatically performed without intervention of the operator, the load on the operator is greatly reduced, and labor saving can be realized.

In addition, the estimation of the adhered amount b of microorganisms is performed based on the current value a of the motor 20 measured by the ammeter 25. There is no need to use various water quality sensors. The ammeter 25 is less expensive than water quality sensors such as DO meters and pH meters, and unlike these water quality sensors, maintenance is simple, so the water treatment system 100 of the present embodiment can reduce costs and Moreover, it is also possible to reduce the load of maintenance.

Furthermore, in the water treatment system 100 of the present embodiment, washing is realized only by increasing the number of rotations of the rotating disc body 12 compared to normal operation, and special equipment for washing is not required. Therefore, it can be realized with a simple configuration.

Thus, according to the water treatment system 100 of the present embodiment, it is possible to reduce maintenance costs, save labor, improve efficiency in operation, and simplify the configuration.

Although the water treatment system 100 of the first embodiment has been described above, the water treatment system 100 of the first embodiment can also be realized by the following modified examples 1, 2, and 3.

(Modification 1 of the first embodiment)
In modification 1 of the first embodiment, unlike the above-described first embodiment, regarding the setting of the number of rotations per unit time of the rotary disk member 12, the number of rotations c and the number of rotations d are set by the monitoring device 50. Instead of setting from , it is directly set in the rotation speed switching unit 43 of the controller 40 as an internal parameter.

As a result, the operating rotation speed setting unit 51 and the cleaning rotation speed setting unit 52 can be omitted from the monitoring device 50, so that the configuration can be further simplified.

(Modification 2 of the first embodiment)
In modification 2 of the first embodiment, unlike the first embodiment described above, the number of rotations per unit time is dynamically changed based on the amount of microorganisms adhering to the rotary disc body 12 .

FIG. 5 is a block diagram showing a configuration example of a controller and a monitoring device in the water treatment system of Modification 2 of the first embodiment.

As described above with reference to FIG. 3, the adhesion amount estimator 41 estimates the adhesion amount b of microorganisms adhering to the rotary disk member 12 from the current value a during normal operation. 5 differs from FIG. 3 in that the adhesion amount estimation unit 41 shown in FIG. 5 outputs the estimated adhesion amount b not only to the cleaning necessity determination unit 42 and the display unit 53 but also to the rotation speed switching unit 43. .

The rotation speed switching unit 43 determines the rotation speed c per unit time during normal operation based on the adhesion amount b, and outputs the rotation speed c to the motor 20 . The method for determining the number of rotations c is not limited, but for example, the amount of adhesion b as a reference and the number of rotations c at that time are determined in advance, and when the amount of adhesion b increases by 10%, the rotation The number c is also increased by 10%, and conversely, when the adhesion amount b is reduced by 10%, the rotational speed c is also reduced by 10%.

In this way, during normal operation, by dynamically changing the number of rotations per unit time of the rotating disk 12 based on the adhesion amount b of microorganisms adhering to the rotating disk 12, excessive adherence of microorganisms can be prevented. Since microorganisms can be removed during normal operation, the frequency of switching to the cleaning process can be reduced, and the operating rate can be increased.

The switching to the cleaning process in the case of dynamically changing the number of revolutions of the rotary disk member 12 in this manner will be described below.

FIG. 6 is a graph illustrating the relationship between the number of revolutions per unit time of the rotating disk and the current value measured by the ammeter during rotation of the rotating disk.

A straight line (1) in FIG. 6 is a straight line showing the relationship between the rotation speed X and the current value a when no microorganisms adhere to the rotating disk 12, and is generally expressed as a(X)=αX. . On the other hand, the straight line (2) in FIG. 6 is a straight line showing the relationship between the rotation speed X and the current value a when microorganisms adhere to the rotating disc body 12, and is generally expressed as a(X)=αX+δ. . Both α and δ are positive real numbers.

As shown in FIG. 6, even if the rotating disk 12 rotates at the same number of rotations per unit time due to the adherence of microorganisms, the measured current value is higher by the bias current δ. Become.

Therefore, if the magnitude of the bias current δ with respect to the number of rotations per unit time is greater than a predetermined value based on the current value a, the cleaning necessity determination unit 42 determines that the rotating disc body 12 is excessively contaminated with microorganisms. It is determined that there is adhesion, and a cleaning command e is output.

Thus, according to this modification, during normal operation, the number of rotations per unit time of the rotary disc 12 can be dynamically changed based on the amount of microorganisms attached to the rotary disc 12. Even if there is, it can be appropriately switched to the cleaning process.

(Modification 3 of the first embodiment)
In the modification 3 of the first embodiment, unlike the above-described first embodiment, in the step of cleaning the rotary disc 12, the rotary disc 12 is rotated at high speed in order to further enhance the cleaning effect. In addition to , air bubbles collide with the rotating disc body 12 .

FIG. 7 is a conceptual diagram showing a partial configuration example of a water treatment system according to Modification 3 of the first embodiment, and shows a state in which the rotating disk device is viewed from the front side (raw water introduction side in FIG. 1). FIG. 4 is a diagram illustrating an example;

The configuration shown in FIG. 7 is provided with an air diffuser 62 below the rotary disk 12 inside the water treatment tank 11, and an air blower 63 for sending air to the air diffuser 62 outside the water treatment tank 11. is provided, which is different from the configuration shown in FIG.

When the cleaning necessity determining unit 42 determines that cleaning is necessary, it outputs a cleaning command e not only to the motor 20 but also to the blower 63 .

The blower 63 operates in response to the output of the cleaning instruction e from the cleaning necessity determination unit 42 to supply air to the diffuser pipe 62 .

A large number of small holes (not shown) are provided on the surface of the diffuser pipe 62, and the air supplied from the blower 63 becomes bubbles f when passing through these holes, rises in the raw water w, It collides with the rotating disc body 12 located above the diffuser tube 62 .

As a result, during the cleaning process, the rotary disk 12 rotates at a high speed and is hit by air bubbles f from below, thereby more efficiently removing adhering microorganisms.

Showering from above, ultrasonic cleaning, vibration, or the like may be applied as a means for further cleaning the rotary disc body 12 . In addition to colliding the bubbles f, any one of these or any combination thereof may be performed.

Thus, according to this modified example, it is possible to further enhance the cleaning effect during cleaning.

In this modified example, the blower 63 is used only for cleaning. A configuration may be adopted in which the amount of air blown is increased only during the output cleaning step to clean the microorganisms. The air volume at that time is not limited, but for example, it is preferable that the air volume during the cleaning process is at least five times the air volume during normal operation.

(Second embodiment)
A water treatment system to which the water treatment method of the second embodiment is applied will be described.

The second embodiment further includes an imaging unit in addition to the first embodiment.

FIG. 8 is a conceptual diagram showing a configuration example of a water treatment system to which the water treatment method of the second embodiment is applied.

FIG. 9 is a conceptual diagram showing a partial configuration example of the water treatment system of the second embodiment, including a configuration example of the rotating disk device viewed from the front side (raw water introduction side in FIG. 8).

FIG. 10 is a block diagram showing a configuration example of a controller and a monitoring device in the water treatment system of the second embodiment.

In the water treatment system 110 of the present embodiment, as illustrated in FIG. 9, a gas phase 72, which is a space inside a housing cover 70 that covers the upper part of the water treatment tank 11, includes a CCD camera, for example. An imaging unit 71 is arranged.

FIG. 8 shows a configuration example of the rotating disk device 10 viewed from above. As can be seen by comparing FIG. 8 with FIG. 1, the water treatment system 110 is different from the water treatment system 100 in that the ammeter 25 is not provided and the imaging unit 71 is provided.

9 shows an example in which the imaging unit 71 is fixed to the inner surface of the top plate of the housing cover 70, but the imaging unit 71 is fixed to the inner surface of the side plate of the housing cover 70. Alternatively, if it is in the gas phase 72, it may be fixed to a dedicated fixing member (not shown) other than the housing cover .

In FIG. 8, the imaging unit 71 is shown to be removed from the top of the water treatment tank 11, but this is done for convenience to avoid complicating the drawing. Actually, as shown in FIG. 9, the imaging unit 71 is provided above the water treatment tank 11 .

Also in the water treatment system 110 having such a configuration, as in the first embodiment, when the operation of purifying the raw water w by the rotating disk device 10 is continued, the surface of the contact body 14, that is, the rotating disk body 12 Microorganisms adhering to the surface proliferate, and the adhering amount b increases. Accordingly, the interval L between the adjacent rotary disk members 12 is narrowed to a gap length .DELTA.L (L>.DELTA.L).

The imaging unit 71 images such a state of the rotating disk 12 from above the rotating disk 12 in the gas phase 72 and outputs image information g as the imaging result to the adhesion amount estimating unit 41 . do. The color tone of the image included in the image information g varies greatly depending on the presence or absence of microorganisms.

The adhesion amount estimating section 41 performs image analysis on such image information g and quantifies the image information g, thereby estimating the gap length ΔL for each interval L. FIG. As described above, the color tone of the image included in the image information g varies greatly depending on the presence or absence of microorganisms. can be estimated with precision.

The adhered amount estimating unit 41 further calculates the adhered amount of adhered microorganisms for each rotating disk 12 by (L−ΔL)/2 based on the assumption that the microorganisms grow uniformly even if there is some variation. It is also possible to estimate b. Since the accuracy of the air gap length ΔL is high, the adhesion amount b is similarly estimated with high accuracy.

The adhesion amount estimation unit 41 outputs all the gap lengths ΔL to the cleaning necessity determination unit 42 . Further, instead of or in addition to the air gap length ΔL, the adhesion amount b may be output to the cleaning necessity determining section 42 . Furthermore, the image information g is output to the display section 53 . As a result, the operator can observe the image information g from the display unit 53, and can visually grasp the degree of adherence of the microorganisms to the rotary disk member 12. FIG.

Note that the digitization of the image information g does not necessarily have to be performed by the adhesion amount estimation unit 41, and instead of being performed by the adhesion amount estimation unit 41, it may be performed by a function built in the imaging unit 71, or It may be implemented by another external computing device. Note that when the imaging unit 71 or another external computing device performs digitization, the imaging unit 71 or another external computing device that performed digitization outputs the digitized result to the adhesion amount estimation unit 41, The adhering amount estimator 41 uses the quantification result to determine the air gap length ΔL and the adhering amount b calculated from the air gap length ΔL for each interval L as described above.

The cleaning necessity determining unit 42 sums up all the gap lengths ΔL output from the adhesion amount estimating unit 41 . When the result of summation is equal to or less than a predetermined value, it is determined that microorganisms are excessively adhered to the rotary disk member 12, and a cleaning command e is output.

Alternatively, the cleaning necessity determining unit 42 selects a representative gap length ΔL from the gap lengths ΔL output from the adhesion amount estimating unit 41, and determines if the selected gap length ΔL is equal to or less than a predetermined value. In this case, it may be determined that microorganisms are excessively adhered to the rotating disc body 12, and a cleaning command e may be output.

As an example of selecting a typical air gap length ΔL, for example, as described above, even if there are some variations, based on the assumption that microorganisms grow uniformly, in the rotating disk device 10 The gap length ΔL between two adjacent rotating disc bodies 12 existing on the side (for example, as shown in FIG. 8, when eight rotating disc bodies 12 are arranged in the water treatment tank 11, the left side Select the gap length ΔL4) between the fourth rotating disk 12 (#4) from the left and the fifth rotating disk 12 (#5) from the left as a representative gap length ΔL can be done.

Alternatively, the gap length ΔL1 between the leftmost rotating disk 12 (#1) and the second leftmost rotating disk 12 (#2) in FIG. ΔL may be used. This is because the raw water w is introduced into the water treatment tank 11 from the left side in FIG. 8, so it is considered that more microbes adhere to the rotary disk 12 on the left side in FIG.

When the selected air gap length ΔL is equal to or less than a predetermined value, the cleaning necessity determination unit 42 determines that microorganisms are excessively adhered to the rotating disc body 12, and outputs a cleaning command e.

As an example of a specific criterion for determining whether or not cleaning is necessary based on a single gap length ΔL, if the gap L between the adjacent rotating disc members 12 is 5 cm, the gap length ΔL is 1 cm or less. For example, a cleaning command e is output when it becomes.

In the above description, an example in which the cleaning necessity determination unit 42 determines the necessity of cleaning based on the gap length ΔL has been described. As described in the first embodiment, it is also possible to determine whether or not cleaning is necessary based on the adhesion amount b.

As an example of a specific criterion for determining whether or not cleaning is necessary based on the adhesion amount b, when the interval L between the adjacent rotating disc members 12 is on the order of several cm to 10 cm, the adhesion amount b is 2 cm or more. For example, a cleaning command e is output when

Since the cleaning process is as described in the first embodiment, redundant description is avoided.

As described above, the water treatment system 110 of the present embodiment can have the same effects as the water treatment system 100, and can also have the following unique effects.

That is, the water treatment system 110 can determine whether or not cleaning is necessary based on the gap length ΔL and the adhesion amount b estimated based on the image information g captured by the imaging unit 71 .

In the water treatment system 110, the imaging unit 71 is arranged in the gas phase 72 instead of in water, and images the state of the rotating disk 12 from the gas phase 72, so the image information g obtained is clear. Therefore, the gap length ΔL and the adhesion amount b can be estimated with high accuracy, and the cleaning necessity determination unit 42 can determine whether cleaning is necessary or not with high reliability.

In addition, since the imaging unit 71 is arranged in the gas phase 72 instead of in water, the cleaning of the imaging unit 71 can be done by automatic cleaning using a wiper, and maintenance-free operation is possible.

Furthermore, since the image information g can also be displayed from the display unit 53, the operator can check the image information g displayed from the display unit 53 to check the degree of adhesion of the microorganisms to the rotating disk 12. It can also be grasped visually.

In this way, like the water treatment system 110 of the present embodiment, the water treatment system 100 is configured to include the imaging unit 71 instead of the ammeter 25, and the excessive attachment of microorganisms is determined based on the image information g. As a result, it is possible to reduce the maintenance and management cost, save labor, improve the efficiency of operation, and simplify the configuration similarly to the water treatment system 100 without the need for extra maintenance due to the introduction of the imaging unit 71. Realization is possible.

Alternatively, for example, a plurality of cameras may be installed as the imaging unit 71 to three-dimensionally measure the state of the rotating disk device 10 and display the information as a 3D image on the display unit 53 of the monitoring device 50. It is possible.

Although the water treatment system 110 of the second embodiment has been described above, the water treatment system 110 of the second embodiment is also a modification of the first embodiment, like the water treatment system 100 of the first embodiment. Configurations such as those described in Examples 1, 2 and 3 can be applied. In addition to that, the water treatment system 110 of the second embodiment can also be realized by Modifications 1, 2, and 3 as follows.

(Modification 1 of the second embodiment)
In modification 1 of the second embodiment, unlike the above-described second embodiment, a laser rangefinder, a photoelectric sensor, or the like is applied instead of the imaging unit 71 .

FIG. 11 is a conceptual diagram showing a partial configuration example of the water treatment system, including a configuration example of the rotary disk device in the water treatment system of Modification 1 of the second embodiment, viewed from the side.

As exemplified in FIG. 11, in this modification also, the upper part of the water treatment tank 11 is covered with a housing cover 70 as in FIG. not provided, instead a laser range finder 80 is provided.

The laser rangefinder 80 measures the distance to the microorganisms adhering to the rotating disk 12 selected as a representative, and outputs the measurement result i to the adhering amount estimator 41 . As a method of selecting the representative rotary disk 12, as shown in FIG. Rotating disc body 12 (#4) can be used as a representative.

The adhesion amount estimator 41 estimates the adhesion amount of microorganisms based on the measurement result i from the laser rangefinder 80 . Since the location where the laser rangefinder 80 is installed is known, the distance and orientation from the laser rangefinder 80 to the representative rotating disk 12 (#4) are also known in advance. This azimuth corresponds to the irradiation angle θ (angle with respect to the vertical direction) shown in FIG. Therefore, the adhesion amount estimating unit 41 uses the distance and direction from the laser rangefinder 80 to the representative rotating disk 12 (#4) and the measurement result i from the laser rangefinder 80 to It is possible to estimate the adhesion amount b of microorganisms adhering to the representative rotary disk 12 (#4).

Also, instead of the laser rangefinder 80, a reflective photoelectric rangefinder can be applied. The reflective photoelectric range-finding sensor projects visible light and infrared light onto the surface of, for example, a representative rotating disc body 12 (#4), and receives the reflected light. Measure the distance to the surface of body 12 (#4). Based on the measurement result obtained by such a photoelectric ranging sensor, the adhesion amount estimating section 41 determines the representative rotating disk 12 (# 4) can estimate the adhesion amount b of microorganisms adhering. The adhesion amount estimation unit 41 outputs the estimated adhesion amount b to the cleaning necessity determination unit 42 .

The cleaning necessity determination unit 42 determines necessity of cleaning based on the estimated adhesion amount b. Since the rest of the configuration is as described above, the description is omitted.

Thus, according to this modification, it is also possible to apply the laser rangefinder 80 or the photoelectric rangefinder instead of the imaging unit 71 .

(Modification 2 of the second embodiment)
In the modified example 2 of the second embodiment, unlike the above-described second embodiment, imaging is performed in order to obtain information necessary for estimating the adhesion amount b of microorganisms adhering to the rotating disk body 12. The unit 71, the laser rangefinder 80, and the photoelectric rangefinder 81 are all applied.

FIG. 12 is a conceptual diagram showing a partial configuration example of a water treatment system, including a configuration example of a rotating disk device viewed from the side in Modification 2 of the second embodiment.

As exemplified in FIG. 12, in this modified example, as in the second embodiment described above, the upper part of the water treatment tank 11 is covered with a housing cover 70 as in FIG. In the phase 72, an imaging unit 71, a laser rangefinder 80, and a photoelectric rangefinder 81 are installed at known locations.

The imaging unit 71 outputs the image information g to the adhesion amount estimating unit 41 as described above.

As described above, the laser rangefinder 80 transmits the distance to the surface of a representative rotating disk 12 (for example, rotating disk 12 (#4)), which is the measurement result i, to the adhesion amount estimating unit 41. Output.

The photoelectric ranging sensor 81 outputs the distance to the surface of a typical rotating disk 12 (for example, rotating disk 12 (# 6 )), which is the measurement result j, to the adhesion amount estimating section 41 .

The adhesion amount estimation unit 41 estimates the adhesion amount b from the image information g, as described above. Further, as described above, the adhesion amount b is also estimated from the measurement result i. Further, the adhesion amount b is also estimated from the measurement result j in the same manner as the method for estimating the adhesion amount b from the measurement result i.

In this manner, the adhesion amount estimation unit 41 can simultaneously estimate three adhesion amounts b. At the same time, the estimated three adhesion amounts b are all output to the cleaning necessity determination unit 42 .

The cleaning necessity determining unit 42 outputs a cleaning command e when any value or an average value among the three adhesion amounts b output at the same time is larger than a predetermined value.

By adopting such a configuration, it is possible to conservatively determine the state in which microorganisms are excessively adhered to the rotating disc body 12, and to output the cleaning command e. Further, even if any one of the imaging unit 71, the laser rangefinder 80, and the photoelectric rangefinder 81 fails, the amount b of adhered microorganisms is estimated, and if necessary, the cleaning command e can be output.

In addition, although the case where all of the imaging unit 71, the laser rangefinder 80, and the photoelectric rangefinder 81 are used has been described above, any two of them may be used. Even in a configuration using two of the imaging unit 71, the laser rangefinder 80, and the photoelectric rangefinder 81, even if one of them fails, the amount b of adhered microorganisms can be estimated and, if necessary, can output a cleaning command e.

(Modification 3 of the second embodiment)
In the modification 3 of the second embodiment, unlike the above-described second embodiment, the image information g is used not only for estimating the adhesion amount b of microorganisms but also for determining the anaerobic degree of microorganisms. In addition, both the adhesion amount b and the degree of anaerobicity are considered for determining whether or not cleaning is necessary.

FIG. 13 is a block diagram showing a configuration example of a controller and a monitoring device in a water treatment system according to modification 3 of the second embodiment.

A controller 40 illustrated in FIG. 13 has a configuration in which an anaerobic degree determination unit 44 is added to the controller 40 illustrated in FIG. 10 .

The anaerobic degree determination unit 44 receives the image information g output from the imaging unit 71, determines whether the anaerobic degree of microorganisms is high or low based on the image information g, and outputs the determination result k to the cleaning necessity determination unit 42. . When the amount of microorganisms adhering to the rotating disk 12 is appropriate and air is properly supplied to the microorganisms, the color of the microorganism film is usually brown to dark brown.

On the other hand, when microorganisms adhere excessively to the rotary disk 12 and the microorganisms are not supplied with sufficient air, the film of the microorganisms turns black. From the color tone obtained by image analysis of the image information g, the anaerobic degree determination unit 44 determines that the anaerobic degree is low when the color of the microbial film is brown to dark brown, and the anaerobic degree is determined to be black. If so, it is determined that the degree of anaerobicity is high.

As an example of a specific criterion for determining whether the anaerobic level is high or low, for example, when the RGB values of red, green, and blue in the image information g are all 40 or less, it is considered to have turned black, and the anaerobic level is determined to be high. Otherwise, it can be determined that the anaerobic degree is low.

As described with reference to FIG. 10, the adhesion amount estimating unit 41 outputs the air gap length ΔL and the adhesion amount b to the cleaning necessity determination unit 42. As shown, the determination result k from the anaerobic degree determination unit 44 is also output.

The cleaning necessity determining unit 42 not only determines that microorganisms are excessively attached to the rotating disc body 12 based on the air gap length ΔL or the adhesion amount b, but also determines the determination from the anaerobic degree determining unit 44. Also when the result k indicates that the degree of anaerobicity is high, the cleaning command e is output.

As a result, the water treatment system of this modified example can more appropriately determine the timing of switching to the cleaning process.

(Third embodiment)
A water treatment system to which the water treatment method of the third embodiment is applied will be described.

In the third embodiment, the second embodiment is further provided with a nutrient storage tank and a nutrient adding section.

FIG. 14 is a conceptual diagram showing a configuration example of a water treatment system to which the water treatment method of the third embodiment is applied.

The water treatment tank 11 shown in FIG. 14 is viewed from the side as shown in FIG.

FIG. 15 is a block diagram showing a configuration example of a controller and a monitoring device in the water treatment system of the third embodiment.

FIG. 16 is a diagram for explaining adhesion amount control of microorganisms by a water treatment system to which the water treatment method of the third embodiment is applied.

In the water treatment system 120 of the third embodiment, similarly to the water treatment system 110 of the second embodiment, the imaging unit 71 is provided in the gas phase 72 of the rotating disk device 10, but the water treatment system Unlike 110 , it further comprises a nutrient storage tank 90 and a nutrient adding section 91 . The controller 40 also includes a nutrient addition determination unit 45 .

The adhered amount estimation unit 41 also outputs the adhered amount b of microorganisms estimated based on the image information g to the nutrient addition determination unit 45 as described in the second embodiment.

As shown in FIG. 16 , the nutrient addition determination unit 45 outputs an operation command m to the nutrient addition unit 91 when the adhering amount b is equal to or less than a predetermined value Q. As shown in FIG.

The nutrient storage tank 90 is a tank that stores a nutrient n that promotes the growth of microorganisms. As the nutrient n, a nutrient containing a component of silica or magnesium is suitable.

The nutrient addition unit 91 is, for example, a pump, and operates according to an operation command m from the nutrient addition determination unit 45 to add the nutrient n stored in the nutrient storage tank 90 to the raw water w.

As a result, the growth of microorganisms in the raw water w can be promoted, and the adherence amount b of microorganisms adhering to the surface of the rotary disk 12 can be increased. On the other hand, when the adhesion amount b of microorganisms adhering to the surface of the rotating disk 12 is larger than the predetermined value Q, the nutrient addition determination unit 45 does not output the operation command m, so the nutrient addition unit 91 operates. Therefore, the nutrient n is not added from the nutrient storage tank 90 to the raw water w.

In addition, as shown in FIG. 16, in the water treatment system 120 of the present embodiment, when the adhesion amount b of microorganisms is larger than the predetermined value I, which is the upper limit of the appropriate film thickness, cleaning is required as described above. Since the non-determining unit 42 outputs the cleaning command e, the adhered microorganisms can be removed from the rotary disk member 12 by peeling or the like by switching to the cleaning step.

As described above, in the water treatment system 120 of the present embodiment, the amount b of microorganisms adhering to the surface of the rotating disk 12 is reduced within an appropriate range by combining the addition of the nutrient n and the washing. Therefore, it is possible to stably and sustainably provide aquatic environmental performance suitable for suppressing the generation of odors and removing organic matter and nitrogen.

In addition, in order to estimate the adhesion amount b, the adhesion amount estimation unit 41 uses not only the image information g from the imaging unit 71 but also the current value a from the ammeter 25 and the laser rangefinder 80 as described above. At least one of the measurement result i and the measurement result j by the photoelectric ranging sensor 81 can be used.

Although the water treatment system 120 of the third embodiment has been described above, the water treatment system 120 of the third embodiment is also a modification of the first embodiment, like the water treatment system 100 of the first embodiment. Configurations such as those described in Examples 1, 2 and 3 can be applied. The water treatment system 120 of the third embodiment can also be realized by Modification 1 as follows.

(Modification 1 of the third embodiment)
In modification 1 of the third embodiment, unlike the above-described third embodiment, regarding addition of nutrient n, only so-called on/off control is performed to control only whether or not nutrient n is added. Instead, the amount of nutrient n to be added is dynamically changed based on the amount b of microorganisms adhering to the rotary disk 12 .

Specifically, the nutrient addition determining unit 45 determines the addition amount to be smaller as the adhesion amount b is larger, and the addition amount is smaller as the adhesion amount b is smaller. Determine the value to be the larger value.

The nutrient addition determining unit 45 outputs to the nutrient addition unit 91 an operation command m that designates the value of the addition amount determined in this way.

The nutrient addition unit 91 operates to add the amount of nutrient n specified by the operation command m. Specifically, the operation is performed for a time corresponding to the addition amount designated by the operation command m. That is, if the value of the addition amount specified by the operation command m is a small value, the nutrient addition unit 91 operates only for a short time, and the value of the addition amount specified by the operation command m is a large value. If so, the nutritional supplement addition unit 91 operates for a long time.

Accordingly, the smaller the adhesion amount b, the longer the nutrient addition unit 91 operates, so that more nutrient n is added and the growth of microorganisms is promoted. Conversely, the larger the adhesion amount b, the shorter the period of operation of the nutrient addition unit 91, so that only a small amount of the nutrient n is added and the growth of microorganisms is not promoted so much.

In this way, by dynamically determining the amount of the nutrient n to be added based on the adhesion amount b of the microorganisms adhering to the rotating disk 12, the adhesion amount b is kept within an appropriate range. In addition, since it can be dynamically controlled, it is possible to stably and sustainably provide water quality environmental performance suitable for suppressing odor generation and removing organic substances and nitrogen. In this modified example, a method of controlling the amount of nutrient added by time is shown, but the method is not limited to this method. A method of controlling the increase or decrease, or a method of disposing a flow control valve in the outlet side pipe of the nutrient addition pump and controlling the increase or decrease of the flow rate by controlling the control valve may be used.

(Fourth embodiment)
A water treatment system to which the water treatment method of the fourth embodiment is applied will be described.

A fourth embodiment is an example in combination with biological reactions.

FIG. 17 is a conceptual diagram showing a configuration example of a water treatment system to which the water treatment method of the fourth embodiment is applied.

The water treatment tank 11 shown in FIG. 17 is viewed from the side as shown in FIG.

FIG. 18 is a block diagram showing a configuration example of a controller and monitoring device in the water treatment system of the fourth embodiment.

In the water treatment system 130 of the fourth embodiment, the imaging section 71 is arranged in the gas phase 72 of the rotating disk device 10, like the water treatment system 110 of the second embodiment. However, unlike the water treatment system 110, the biological reaction tank 92 in which the air diffuser 93 is arranged, the blower 94 that supplies air to the air diffuser 93, the sedimentation tank 95, and the sedimentation tank 95 and the water treatment tank 11 A sludge return pipe 97 connected therebetween and a sludge return section 96 provided in the sludge return pipe 97 are further provided. The controller 40 also has a sludge return determination section 46 .

The treated water x from the rotating disk device 10 is introduced into the biological reaction tank 92 . In the biological reaction tank 92, contaminants such as organic matter remaining in the treated water x are further decomposed by the action of activated sludge, which is a collection of microorganisms. Thereby, advanced treated water can be obtained. In the biological reaction tank 92, air bubbles are generated in the diffuser pipe 93 supplied with air from the blower 94, and the oxygen in the bubbles is used by the microorganisms in the activated sludge in the biological reaction tank to oxidize pollutants such as organic substances. decomposed.

The treated water y containing solids such as activated sludge is discharged from the biological reaction tank 92 and introduced into the sedimentation tank 95 . Solid matter contained in the treated water y precipitates in the sedimentation tank 95, thereby separating the treated water y into solids and liquids. The treated water z, which is the liquid component after solid-liquid separation, is finally discharged to a discharge destination such as a river after going through a disinfection process and the like. The solid content after solid-liquid separation is returned to the water treatment tank 11 . This returned solid content is called return sludge.

The adhesion amount estimation unit 41 also outputs the adhesion amount b of microorganisms estimated based on the image information g as described in the second embodiment to the sludge return determination unit 46 .

The sludge return determination unit 46 outputs an operation command p to the sludge return unit 96 when the adhesion amount b is equal to or less than a predetermined value.

The sludge return unit 96 is, for example, a pump, and operates according to the operation command p from the sludge return determination unit 46 . A sludge return pipe 97 provided with a sludge return section 96 is connected to the bottom of the sedimentation tank 95 . Therefore, when the sludge return section 96 operates, the sludge that has settled in the sedimentation tank 95 is sucked into the sludge return pipe 97 by the sludge return section 96 and transferred to the rotating disk device 10 . Since the sludge contains microorganisms, the microorganisms are returned to the rotating disk device 10 by this.

In this way, the controller 40 controls the operation of the sludge return unit 96 based on the adherence amount b of microorganisms estimated by the adherence amount estimation unit 41, and returns the sludge to the rotating disk device 10, thereby rotating the Microorganisms are supplied to the disc device 10 .

As a result, when the amount of microorganisms is small, the amount of microorganisms in the raw water w can be increased by returning sludge containing microorganisms to the rotating disk device 10 .

As described above, according to the water treatment system 130 of the present embodiment, it is possible to control the return of sludge based on the adhesion amount b of the microorganisms adhering to the rotating disc body 12. By combining with, the adhesion amount b of microorganisms adhering to the rotating disk 12 can be appropriately maintained, and the water quality environmental performance suitable for suppressing odor generation and removing organic matter and nitrogen can be stably maintained. and can be provided continuously.

As a result, the rotating disk device 10 can reduce the load on the biological reaction tank 92 provided in the latter stage. For this reason, the biological reaction tank 92 can significantly reduce the power consumption cost of the blower 94 compared to a configuration without the rotating disk device 10 in the front stage (for example, the standard activated sludge method or the circulating nitrification/denitrification method). In addition, the size of the biological reaction tank 92 can be reduced.

Therefore, when the existing biological reaction treatment process adopts a water treatment process using activated sludge such as the standard activated sludge method, a water treatment system including the rotating disk device 10 can be introduced in the front stage. , it is possible to save energy and stabilize the water quality environment.

Although the water treatment system 130 of the fourth embodiment has been described above, the water treatment system 130 of the fourth embodiment is also a modification of the first embodiment, like the water treatment system 100 of the first embodiment. Configurations such as those described in Examples 1, 2 and 3 can be applied. The water treatment system 130 of the fourth embodiment can also be realized by modified examples 1 and 2 below.

(Modification 1 of the fourth embodiment)
In the modification 1 of the fourth embodiment, unlike the fourth embodiment described above, regarding the return of sludge, only so-called on/off control that controls only whether or not to return is performed, but the return is performed. The amount of sludge is dynamically determined based on the adhered amount b of microorganisms adhering to the rotating disk 12 .

FIG. 19 is a diagram for explaining the relationship between the adhesion amount of microorganisms adhering to a flat plate and the amount of sludge returned.

As shown in FIG. 19, the sludge return determination unit 46 determines that when the adhesion amount b is equal to or less than a predetermined value u and the sludge return unit 96 is operated, the amount of sludge returned increases as the adhesion amount b decreases. The sludge return section 96 is operated for a longer period of time.

The sludge return determination unit 46 outputs to the sludge return unit 96 an operation command p specifying an operation time of the sludge return unit 96 corresponding to the sludge return amount.

The sludge return unit 96 operates for a short time if the value of the sludge return amount specified by the operation command p is small, and operates for a long time if the value is large.

As a result, when the adhesion amount b is equal to or less than the predetermined value u, the smaller the adhesion amount b, the longer the sludge return unit 96 operates and the more sludge is returned to the water treatment tank 11. As a result, more microorganisms are supplied to the raw water w.

When the adhesion amount b is larger than the predetermined value u, the cleaning instruction e is output from the cleaning necessity determination unit 42, thereby switching to the cleaning process as described above and cleaning is started. , microorganisms adhering to the rotating disc body 12 are removed.

In this way, by dynamically determining the amount of sludge to be returned to the water treatment tank 11 based on the adhesion amount b of the microorganisms adhering to the rotating disc body 12 and the washing process, the adhesion amount b can be dynamically controlled so that the temperature is kept within an appropriate range, stably and continuously provide water treatment performance such as suppression of odor generation and removal of organic matter and nitrogen. becomes possible. In this modified example, a method of controlling the amount of sludge returned by time is shown, but the method is not limited to this method. Alternatively, a flow control valve may be provided in the outlet pipe of the sludge return pump to control the increase or decrease of the flow rate by controlling the control valve.

(Modification 2 of the fourth embodiment)
FIG. 20 is a conceptual diagram showing a configuration example of a water treatment system of modification 2 of the fourth embodiment.

FIG. 21 is a block diagram showing a configuration example of a controller and a monitoring device in a water treatment system of modification 2 of the fourth embodiment.

Unlike the water treatment system 130 of the fourth embodiment described above, the water treatment system 140 of Modification 2 of the fourth embodiment is different from the water treatment system 120 of the third embodiment, as shown in FIG. It has a configuration in which it is combined with the water treatment system 130 of the fourth embodiment. Furthermore, as shown in FIG. 21, the controller 40 includes both a nutrient addition determination unit 45 shown in FIG. 15 and a sludge return determination unit 46 shown in FIG. As described above, the adhesion amount b is output to the rotational speed switching section 43 .

With such a configuration, the controller 40 determines whether or not the nutrient addition unit 91 adds the nutrient n, and the sludge return unit 96 determines whether or not the nutrient addition unit 91 adds the nutrient n based on the adhesion amount b of the microorganisms estimated by the adhesion amount estimation unit 41. At least one of the presence or absence of return can be controlled.

Alternatively, the controller 40 determines, based on the adhered amount b of microorganisms estimated by the adhered amount estimating section 41, At least one of them can be controlled.

Furthermore, as described with reference to FIG. 5, during normal operation, the rotary disc member 12 can be rotated at a number of revolutions determined based on the adhesion amount b.

With such a configuration, when the number of microorganisms adhering to the surface of the rotating disk 12 is small, the growth of microorganisms is promoted, and when there are many microorganisms, the growth of microorganisms is suppressed. By removing the microorganisms adhering to the surface of the rotary disk member 12, the adhesion amount b of the microorganisms adhering to the surface of the rotating disc body 12 can be flexibly controlled so as to be within an appropriate range. As a result, it is possible to stably and sustainably provide water quality environmental performance suitable for suppressing the generation of odors and removing organic matter and nitrogen.

(Fifth embodiment)
A water treatment system to which the water treatment method of the fifth embodiment is applied will be described.

In a fifth embodiment, sonic detection is used to estimate the amount of microorganisms adhering to the rotating disc.

FIG. 22 is a conceptual diagram showing a configuration example of a rotating disk device in a water treatment system to which the water treatment method of the fifth embodiment is applied.

FIG. 22 is a conceptual diagram showing a configuration example of a water treatment system to which the water treatment method of the fifth embodiment is applied.

23 is a block diagram showing a configuration example of a controller and a monitoring device in the water treatment system of the first embodiment; FIG.

The rotating disk device 10 in the water treatment system 150 shown in FIG. 22 corresponds to the rotating disk device 10 shown in FIG. A sound wave receiver 32 is provided. A pair of one sound wave source 31 and one sound wave receiver 32 arranged oppositely constitutes one detection unit.

The detection unit is a non-contact sensor that performs detection for estimating the amount of microorganisms adhering to the rotating disc body 12. Each detection unit, as illustrated in FIG. , and one acoustic wave receiver 32 arranged oppositely. A sound wave source 31 emits a sound wave S towards a paired sound wave receiver 32, which receives this sound wave S and generates a received signal s corresponding to the energy of the received sound wave S. is output to the adhesion amount estimation unit 41 of the controller 40 .

The acoustic wave source 31 and the acoustic wave receiver 32 forming a pair are arranged at the same height in the gas phase 72, lower than the upper end of the rotating disc 12. FIG. Furthermore, the sound wave S emitted from the sound wave source 31 passes through the gap 16 parallel to the end face 12a, that is, in the direction in which the gap 16 extends, and is received by the sound wave receiver 32. A sound wave source 31 and a sound wave receiver 32 are arranged to face each other.

The width of the gap 16 is equal to the gap L when no microorganisms adhere to the surface of the contactor 14 . However, the width of the gap 16 becomes narrower than the gap L when the microorganisms grow and adhere to the surface of the contactor 14 .

When the width of the gap 16 is narrowed, it becomes difficult for the sound wave S to pass through, so the energy of the sound wave S received by the sound wave receiver 32 is also low. Using this phenomenon, the water treatment system 150 estimates the amount of adhered microorganisms in the adhered amount estimator 41 of the controller 40 .

The acoustic wave source 31 and the acoustic wave receiver 32 forming a pair are located in the gas phase 72, for example, at a height approximately ⅓r lower than the radius r of the rotary disc 12 from the upper end of the rotary disc 12. are placed in Thus, it is preferable to arrange the sound wave source 31 and the sound wave receiver 32 at a height somewhat lower than the upper end of the rotating disk 12 . This is because when the rotating disc 12 rotates, the outer end of the rotating disc 12 receives the strongest centrifugal force. This is because the amount of adherent microorganisms to be treated is reduced.

As shown in FIG. 23 , the controller 40 includes an adhesion amount estimation section 41 , a cleaning necessity determination section 42 and a rotational speed switching section 43 .

The monitoring device 50 functions as an interface with the operator of the water treatment system 150, and includes an operating rotation speed setting unit 51, a cleaning rotation speed setting unit 52, and a display unit 53 such as a display.

The adhesion amount estimator 41 receives the reception signal s output from the sound wave receiver 32 and estimates the adhesion amount b of the microorganisms on the surface of the rotating disk 12 from the reception signal s. This principle will be explained below.

FIG. 24 is a diagram illustrating the general relationship between energy and frequency of sound waves received by a sound wave receiver.

In FIG. 24, the vertical axis E represents the energy of the sound wave S received by the sound wave receiver 32, the horizontal axis λ represents the frequency, and the curve α1 represents the case where no microorganisms are present in the gap 16, that is, the rotating disk An example of the energy distribution of the sound wave S received by the sound wave receiver 32 when no microorganisms adhere to the surface of the body 12 is shown. An example of the energy distribution of the sound waves S received by the sound wave receiver 32 is shown when microorganisms adhere to the surface of the plate 12 . As can be seen by comparing the curve α1 and the curve α2, when microorganisms adhere to the surface of the rotating disk 12, the peak energy decreases by ΔE in accordance with the amount of adherence.

The adhered amount estimator 41 grasps in advance the correlation between the adhered amount of microorganisms on the surface of the rotating disc body 12 and the decrease amount ΔE of the peak energy. Then, when the reception signal s is output from the sound wave receiver 32, the adherence amount of microorganisms on the surface of the rotating disk 12 is estimated from this correlation. Then, the estimated adherence amount b is output to the cleaning necessity determining section 42 and the display section 53 of the monitoring device 50 .

FIG. 24 shows an example in which the frequency indicating the peak energy does not change regardless of whether or not microorganisms adhere to the surface of rotating disk 12. However, if microorganisms adhere to the surface of rotating disk 12, , the frequency indicating the peak energy may shift depending on the adhesion amount.

FIG. 25 is a diagram illustrating another relationship between energy and frequency of sound waves received by a sound wave receiver.

FIG. 25 shows an example in which the frequency indicating the peak energy shifts by Δλ depending on the amount of microorganisms adhered to the surface of the rotating disk 12. The curve α3 represents an example of the energy distribution of the sound wave S received by the sound wave receiver 32 when the sound wave receiver 32 does not An example of the energy distribution of a received sound wave S is shown. As can be seen by comparing the curve α1 and the curve α3, when microorganisms adhere to the surface of the rotating disk 12, the frequency indicating the peak energy shifts by Δλ and the peak energy decreases by ΔE depending on the amount of adherence. .

Also in this case, the adhesion amount estimator 41 grasps in advance the correlation between the adhesion amount of microorganisms on the surface of the rotating disc body 12 and the peak energy decrease amount ΔE. Then, when the reception signal s is output from the sound wave receiver 32, the adherence amount of microorganisms on the surface of the rotating disk 12 is estimated from this correlation. Then, the estimated adherence amount b is output to the cleaning necessity determining section 42 and the display section 53 of the monitoring device 50 .

As illustrated in FIG. 22, the number of detection units 30 arranged in the rotating disk device 10 is not limited to one, and may be plural.

As illustrated in FIG. 22, when the detectors 30 are arranged in the respective gaps 16, the sound wave receivers 32 of the respective detectors 30 output the received signal s to the adhesion amount estimator 41. . As a result, the adhered amount estimating section 41 can grasp the decrease in the width of each gap 16 and estimate the adhered amount of microorganisms on the surface of each rotating disk 12 based on this. For example, when the width of the gap 16 (#1) is decreased, half of the decrease is divided between the surface of the rotating disk 12 (#1) on the side of the gap 16 (#1) and the surface of the rotating disk 12 (#1). 12 (#2) and the surface of the gap 16 (#1).

In addition, FIG. 22 shows, as an example, a configuration in which one detection unit 30 , that is, a pair of sound wave transmission source 31 and sound wave receiver 32 is arranged for all gaps 16 . However, the detection units 30 do not necessarily have to be arranged for all the gaps 16 , and may be arranged for only some typical gaps 16 . Also, a plurality of detection units 30 may be arranged for one gap 16 .

An example in which the detection unit 30 is arranged only in the representative gap 16 will be described.

The representative gap 16 is preferably the gap 16 where the raw water w has the highest concentration. For example, in the example shown in FIG. 22, it corresponds to the gap portion 16 (#1). This is because the higher the concentration of the raw water w (the left side in FIG. 22), the higher the contamination concentration, the easier it is for microorganisms to grow, and the larger the adhered amount. Therefore, the gap 16 (#1) is considered to have the largest amount of microorganisms among the seven gaps 16 illustrated in FIG.

22, between the inner wall of the water treatment tank 11 and the rotating disc body 12 (#1), and between the inner wall of the water treatment tank 11 and the rotating disc body 12 (#8). is not a gap between two adjacent rotating disc bodies 12, so it is excluded from consideration of typical gaps.

Next, an example in which a plurality of detection units 30 are arranged in one gap 16 will be described.

FIG. 26 is a partial side view of a rotating disk device showing an arrangement example in which four detection units are arranged in one gap.

FIG. 27 is a conceptual diagram showing another configuration example of the rotary disk device shown in FIG. 26 viewed from the front side (left side in FIG. 26).

In FIG. 26, a portion including the gaps 16 (#1), 16 (#2), and 16 (#3) in FIG. 1 is enlarged.

As illustrated in FIG. 26, in each of the gaps 16(#1), 16(#2), and 16(#3), the four detection portions 30a to 30d are arranged in the longitudinal direction of the shaft 13 (right and left in FIG. 22). direction) and the height direction (depth direction in FIG. 22) of the rotating disc body 12 so as to shift little by little.

For example, the four detection units 30a (#2), 30b (#2), 30c (#2), and 30d (#2) are different in distance from the end surface 12a of the rotating disk 12 (#2). That is, the four sound wave sources 31a (#2), 31b (#2), 31c (#2), and 31d (#2) have different distances from the end surface 12a of the rotating disk 12 (#2). , the four sound wave receivers 32a (#2), 32b (#2), 32c (#2), and 32d (#2) are different in distance from the end surface 12a of the rotating disk 12 (#2).

Further, for example, each of the four detection units 30a (#2), 30b (#2), 30c (#2), and 30d (#2) has a height from the upper end of the rotating disc body 12 (#2). is different. That is, the four sound wave sources 31a (#2), 31b (#2), 31c (#2), and 31d (#2) each have a height of Differently, the four sound wave receivers 32a (#2), 32b (#2), 32c (#2), and 32d (#2) each have a height of different.

Also, FIG. 27 shows an example of the height relationship between the four pairs of sound wave sources 31a to 31d and sound wave receivers 32a to 32d arranged in one gap 16 and the rotary disk member 12. there is

In each of the four detection units 30a to 30d, a pair of the sound wave source 31 and the sound wave receiver 32 are arranged at the same height in the gas phase 72, at a height lower than the upper end portion of the rotating disc body 12. FIG.

As a result, the sound wave Sa emitted from the sound wave source 31a passes through the gap 16 parallel to the end surface 12a, that is, in the extending direction of the gap 16, and is received by the sound wave receiver 32a. Similarly, the sound wave Sb transmitted from the sound wave source 31b is transmitted by the sound wave receiver 32b, the sound wave Sc transmitted from the sound wave source 31c is transmitted by the sound wave receiver 32c, and the sound wave Sd transmitted from the sound wave source 31d is transmitted by the sound wave receiver 32b. , are received by the acoustic wave receiver 32d.

As a result, sound waves Sa, sound waves Sb, sound waves Sc, and sound waves Sd travel in the horizontal direction and parallel to the end surface 12a, but in the longitudinal direction of the shaft 13 (horizontal direction in FIG. 26). The position and the position in the height direction (vertical direction in FIGS. 26 and 27) of the rotary disk 12 are different.

The four sound wave sources 31a to 31d and the four sound wave receivers 32a to 32d are arranged so as to be shifted little by little with respect to the longitudinal direction of the shaft 13 and the height direction of the rotating disc body 12. The reason for this is as follows.

First, the reason why the four detection units 30 are arranged so as to be shifted in the longitudinal direction of the shaft 13 is to enable dynamic grasping of the degree of adherence of microorganisms.

As exemplified in FIG. 26, if the four detection units 30 are arranged along the longitudinal direction of the shaft 13 in the order of the detection units 30a→30b→30c→30d from the side closer to the rotating disc body 12, the first First, a decrease in the received energy of the sonic receiver 32a is detected, and then a decrease in the received energy of the sonic receiver 32b is detected. become able to.

As illustrated in FIG. 26, the detection units 30c and 30d are arranged completely within the width of the gap 16, but the detection unit 30a is not within the width of the gap 16, but The detector 30 b is arranged on the side surface of the body 12 , and the detection section 30 b is partly arranged within the width of the gap 16 , but the remaining part is arranged on the side surface of the rotating disc body 12 .

Even if the detectors 30a and 30b are not completely arranged within the width of the gap 16, the rotary disk 12 can be made porous as described above, so that the sound wave source 31a The transmitted sound wave Sa passes through the inside of the porous rotating disk 12 and is received by the sound wave receiver 32a. Similarly, the sound wave Sb emitted from the sound wave source 31b passes through the inside of the porous rotating disk 12 and is received by the sound wave receiver 32b.

The more microbes are present in the porous, the more the energy of the received sound waves is reduced. Therefore, the adhered amount estimator 41 can also grasp the adhered state of the microorganisms inside the rotating disc body 12 .

Next, the reason why the four detectors 30 are arranged so as to be shifted in the vertical direction of the rotary disk 12 is to suppress interference of received signals among the sound wave receivers 32a, 32b, 32c, and 32d. is.

That is, as illustrated in FIG. 26, when a plurality of detection units 30 are arranged in one gap 16, the reception signal s between the plurality of sound wave receivers 32 (for example, between the sound wave receivers 32a to 32d) Concerned about interference. Therefore, in order to physically separate the sound wave receivers 32 as much as possible, the four detectors 30 are arranged to be shifted in the height direction of the rotating disc body 12 .

As a result, even when a plurality of detection units 30 are arranged in one gap 16, it is possible to suppress the interference of the received signal s by each sound wave receiver 32 and evaluate the adherence amount of microorganisms with high accuracy. becomes.

In order to prevent interference of the received signal s, instead of arranging the four detectors 30 by shifting them in the height direction of the rotating disk 12, each detector 30 uses sound waves S of different wavelengths. You can do it. This is realized, for example, by transmitting sound waves S of different frequencies from the sound wave source 31 or by receiving different sound waves S at the sound wave receivers 32 for each detection unit 30 .

In this way, the controller 40 controls the cleaning necessity determination unit 42 and the rotation speed switching unit 43 to determine whether or not the cleaning is necessary according to the adhesion amount b estimated by the adhesion amount estimation unit 41, as described in the first embodiment. Controls the operation of the processing system 150 .

As described above, according to the water treatment system 150 of the present embodiment, like the sound wave source 31 and the sound wave receiver 32, based on the detection result of the detection unit 30, which is a non-contact sensor, the rotating disc body Estimate the adhesion amount b of the microorganisms adhering to 12, and when it is determined that the microorganisms are excessively adhered, the operation mode is switched to the cleaning process, thereby removing the excess microorganisms adhering to the rotating disc body 12. can be removed.

In other words, the determination of whether or not cleaning is necessary can be made based on the quantitative results obtained from the detection results of the detection unit 30 rather than the qualitative determination by the administrator. As a result, the adhesion amount b of microorganisms on the rotary disk member 12 can be kept within an appropriate range, so that water treatment operation suitable for suppressing odor generation and removing organic matter and nitrogen can be stably performed. and can be provided continuously.

Since such operation is automatically performed without intervention of the operator, the load on the operator is greatly reduced, and labor saving can be realized.

In addition, the detection unit 30 does not use various water quality sensors such as a DO meter or a pH meter that are widely used in general water treatment systems, and is realized using an inexpensive sound wave source 31 and a sound wave receiver 32. Since it can be done, the cost can be reduced. In addition, since the sound wave source 31 and the sound wave receiver 32 are used in a non-contact manner without being immersed in liquid, it is possible to extend the service life, reduce the risk of malfunction, reduce running costs, and facilitate maintenance.

In the above description, the sound wave source 31 and the sound wave receiver 32 are fixed to the inner surface of the housing cover 70 as an example, but the housing cover 70 is made of a material that allows the sound waves S to pass through. , the sonic wave source 31 and the sonic wave receiver 32 can also be arranged outside the housing cover 70 .

Moreover, if the water treatment tank 11 is made of a material that allows the sound wave S to pass through, the sound wave source 31 and the sound wave receiver 32 can be arranged at a position lower than the surface of the raw water w.

FIG. 28 is a conceptual diagram showing another configuration example of the rotating disk device viewed from the front side (left side in FIG. 22).

In the configuration shown in FIG. 28, the water treatment tank 11 is made of a material that allows sound waves S to pass through. The sonic wave source 31 and the sonic wave receiver 32 are arranged at a position lower than the liquid surface of the raw water w. In this case, the sound wave S emitted from the sound wave source 31 passes through at least the raw water w and is received by the sound wave receiver 32, but the sound wave S is faster in the liquid phase than in the gas phase 72. Because it propagates, the acoustic wave receiver 32 can receive the acoustic wave S sooner than if it passed through the gas phase 72 . However, in this case, the reception signal s is affected by solids and the like in the raw water w. Vessel 32 is preferably placed in gas phase 72 .

As shown in FIG. 28 , even when the sonic wave source 31 and the sonic wave receiver 32 are arranged at a position lower than the liquid surface of the raw water w, the sonic wave source 31 and the sonic wave receiver 32 are located in the water treatment tank 11 . , so that it is not immersed in the raw water w. Therefore, similarly to the above, the service life of the sonic wave source 31 and the sonic wave receiver 32 is long, and maintenance can be substantially eliminated.

(Modification 1 of the fifth embodiment)
In the fifth embodiment, similarly to the modification 1 of the first embodiment, the rotation speed c during operation and the rotation speed d during cleaning are not set from the monitoring device 50, but are set by the rotation speed switching unit of the controller 40. 43 can also be set directly as an internal parameter.

As a result, the operating rotation speed setting unit 51 and the washing rotation speed setting unit 52 can be omitted from the monitoring device 50, so that the configuration can be further simplified.

(Modification 2 of the fifth embodiment)
In the fifth embodiment, similarly to the modification 2 of the first embodiment, the number of rotations of the rotating disc body 12 during normal operation is changed according to the amount b of microorganisms adhering to the rotating disc body 12. can change dramatically.

FIG. 29 is a block diagram showing a configuration example of a controller and a monitoring device in a water treatment system of modification 2 of the fifth embodiment.

As described above with reference to FIG. 23, the adhered amount estimator 41 estimates the adhered amount b of microorganisms adhering to the rotary disk member 12 based on the detection result of the detector 30 during normal operation. 29 differs from FIG. 23 in that the adhesion amount estimating section 41 shown in FIG. 29 outputs the estimated adhesion amount b not only to the cleaning necessity determination section 42 and the display section 53 but also to the rotational speed switching section 43. .

The rotation speed switching unit 43 determines the operating rotation speed c based on the adhesion amount b, and outputs it to the motor 20 . The method for determining the operating rotation speed c is the same as that described in Modification 2 of the first embodiment, so a description thereof will be omitted.

Thus, according to this modification, as described in modification 2 of the first embodiment, water is added in advance so that the amount of microorganisms adhering to the rotating disc body 12 is kept within an appropriate range. Since the operation of the treatment system 100 can be controlled, the frequency of switching the operation mode from normal operation to the cleaning process can be reduced, thereby increasing the operating rate of the water treatment system 150.

(Modification 3 of the fifth embodiment)
In the water treatment system 150 of the fifth embodiment, during the washing process, the rotating disc body 12 is rotated at a higher speed than during normal operation in order to remove the microorganisms excessively adhering to the rotating disc body 12. As described above, as in the third modification of the first embodiment, in addition to rotating the rotating disk 12 at high speed, air bubbles are generated in the rotating disk 12 in order to further enhance the cleaning effect during the cleaning process. You may make it collide.

According to this modification, it is possible to further enhance the cleaning effect during cleaning.

(Modification 4 of the fifth embodiment)
Modification 3 does not mention the relationship between the amount b of microorganisms adhering to rotating disk 12 and the amount of air bubbles f. The amount of air bubbles f is generated from the diffuser tube 62 while dynamically changing the amount of air bubbles f according to the adhered amount b of microorganisms.

FIG. 30 is a block diagram showing a configuration example of a controller and a monitoring device in a water treatment system of modification 4 of the fifth embodiment.

The block diagram shown in FIG. 30 differs from the block diagram shown in FIG. The adhesion amount estimating section 41 also outputs the adhesion amount b to the diffuser pipe control section 48 .

FIG. 31 is a conceptual diagram showing another configuration example of the rotating disk device according to Modification 4 of the fifth embodiment, viewed from the front side (the left side in FIG. 22).

FIG. 31 shows that the water treatment tank 11 shown in FIG. A blower 63 is shown.

The air diffuser control unit 48 determines the amount of air to be supplied to the air diffuser 62 according to the value of the adhesion amount b output from the adhesion amount estimation unit 41, and outputs a control signal h corresponding to the supply amount to the blower 63. Output to

The air blower 63 supplies air to the diffuser pipe 62 at a supply amount determined by the diffuser pipe controller 48 according to the control signal h.

In this way, in this modification, during normal operation, the air diffuser 62 can generate the air bubbles f while dynamically changing the amount of the air bubbles f depending on the amount b of the microorganisms adhering to the rotating disk 12. . As a result, the microorganisms adhering to the rotating disk 12 can be removed during normal operation. Operation of processing system 150 may be controlled.

As a result, the adherence amount b of microorganisms adhering to the rotary disk member 12 can be kept within an appropriate range, and the frequency of switching the operation mode from normal operation to the cleaning process can be reduced. , it is possible to increase the operating rate of the water treatment system.

(Sixth embodiment)
A water treatment system to which the water treatment method of the sixth embodiment is applied will be described.

The sixth embodiment has a configuration in which a sound wave transmission source and a sound wave receiver are arranged so as to sandwich the rotary disk in the plate thickness direction.

FIG. 32 is a conceptual diagram showing a configuration example of a water treatment system to which the water treatment method of the sixth embodiment is applied.

FIG. 33 is a block diagram showing a configuration example of a controller and a monitoring device in the water treatment system of the sixth embodiment.

The configuration of the water treatment system 160 shown in FIG. 32 differs from the configuration of the water treatment system 150 shown in FIG. 22 only in the arrangement direction of the detection unit 30 . That is, in FIG. 22, the pair of the sonic wave source 31 and the sonic wave receiver 32 are arranged so as to be parallel to the end surface 12a of the rotary disk 12 and face each other in the direction in which the gap 16 extends. On the other hand, in FIG. 32, the pair of the sonic wave source 31 and the sonic wave receiver 32 are arranged so as to sandwich the rotating disk 12 in the plate thickness direction so as to be orthogonal to the arrangement direction in FIG. .

By arranging the pair of the sound wave source 31 and the sound wave receiver 32 in this way, the sound wave S transmitted from the sound wave source 31 is received by the sound wave receiver 32 after passing through the rotating disk 12. be. The rotating disc body 12 is made of a porous material. Therefore, the sound wave S emitted from the sound wave source 31 can pass through the rotating disc body 12 .

When microorganisms adhere to the rotating disc body 12, the pores of the rotating disc body 12 are blocked in accordance with the amount of adhesion. The energy of the sound wave S received by the sound wave receiver 32 is also reduced. The water treatment system 160 utilizes this phenomenon to determine the spatial ratio of the rotating disk 12, and to estimate the adhesion amount b of microorganisms based on the spatial ratio.

For this purpose, the water treatment system 160 has a space ratio determining section 49 in the controller 40, as shown in FIG.

As in the fifth embodiment, the sound wave receiver 32 outputs the received signal s, but in this embodiment, the received signal s is not output to the adhesion amount estimator 41, but is used to determine the spatial ratio. It is output to the unit 49 .

The spatial ratio determination unit 49 determines the spatial ratio G in the rotating disk 12 based on the received signal s, and outputs the determined spatial ratio G to the adhesion amount estimating unit 41 .

The adhered amount estimator 41 estimates the adhered amount b of microorganisms on the rotating disk 12 based on the space ratio G. FIG.

With such a configuration as well, the same effects as those described in the fifth embodiment can be obtained. Note that FIG. 32 shows, as an example, a configuration in which pairs of sound wave transmission sources 31 and sound wave receivers 32 are arranged on all rotating disc bodies 12 . However, as described in the fifth embodiment, it is not necessary to arrange pairs of sound wave sources 31 and sound wave receivers 32 for all rotating discs 12. A pair of sound wave source 31 and sound wave receiver 32 may be arranged only at 12 .

As a typical rotating disk 12, the rotating disk 12 (#1) on the side of the raw water w, which has the largest amount of microorganism growth, can be used.

Also, FIG. 32 shows only an example in which only one pair of the sound wave source 31 and the sound wave receiver 32 is arranged with respect to the same rotating disc body 12. A plurality of pairs may be arranged in . In this case, in order to prevent interference between sound waves S from adjacent pairs of sound wave sources 31, the arrangement height and arrangement position of sound wave source 31 and sound wave receiver 32 may be changed for each pair.

Note that when the pair of the sound wave source 31 and the sound wave receiver 32 is arranged so as to sandwich the rotating disc body 12 in the plate thickness direction as in the present embodiment, it is not preferable to arrange them in the liquid phase. , preferably in the gas phase 72, as illustrated in FIG. This is because, in order to place the sonic wave source 31 and the sonic wave receiver 32 in the liquid phase, it is necessary to house the sonic wave source 31 and the sonic wave receiver 32 in a waterproof cover so as not to immerse them in liquid. This is because, in addition to the additional cost for equipment, the trouble of maintenance also increases.

(Seventh embodiment)
A water treatment system to which the water treatment method of the seventh embodiment is applied will be described.

The seventh embodiment further includes a nutrient storage tank and a nutrient adding section in addition to the fifth and sixth embodiments.

FIG. 34 is a conceptual diagram showing a configuration example of a water treatment system to which the water treatment method of the seventh embodiment is applied.

In the water treatment system 170 illustrated in FIG. 34, the water treatment tank 11 is viewed along the flow direction of the raw water w, as in FIG.

FIG. 35 is a block diagram showing a configuration example of the controller and monitoring device in the water treatment system of the seventh embodiment.

The water treatment system 170 of the seventh embodiment, like the water treatment system 150 of the fifth embodiment and the water treatment system 160 of the sixth embodiment, has a detector in the gas phase 72 of the rotating disk device 10. 30 , but unlike the water treatment systems 150 and 160 , a nutrient storage tank 90 and a nutrient addition section 91 are further provided outside the rotating disk device 10 . In addition to the configuration shown in FIG. 23, the controller 40 also includes a nutritional supplement addition determining section 45. As shown in FIG. Then, the adhesion amount estimating section 41 outputs the estimated adhesion amount b to not only the washing necessity determination section 42 and the display section 53 but also the nutrient addition determination section 45 .

As shown in FIG. 16, the nutrient addition determination unit 45 outputs an operation command m to the nutrient addition unit 91 when the adherence amount b of the microorganisms on the rotating disk 12 is equal to or less than a predetermined value Q. FIG.

The nutrient storage tank 90 is a tank that stores a nutrient n that promotes the growth of microorganisms. As the nutrient n, a nutrient containing a component of silica or magnesium is suitable.

The nutrient addition unit 91 is, for example, a pump, and operates according to an operation command m from the nutrient addition determination unit 45 to add the nutrient n stored in the nutrient storage tank 90 to the raw water w.

In this way, when the amount of microorganisms in the water treatment tank 11 is small, by adding the nutrient n to the raw water w, the growth of microorganisms is promoted and the amount of microorganisms in the water treatment tank 11 is increased. be able to.

On the other hand, when the amount b of microorganisms adhering to the rotary disk 12 is larger than the predetermined value Q, the nutrient addition determination unit 45 does not output the operation command m, so the nutrient addition unit 91 does not operate. The nutrient n is not added from the nutrient storage tank 90 to the raw water w.

However, when the amount b of the microorganisms adhering to the rotating disc body 12 is greater than the predetermined value I, which is the upper limit of the appropriate amount of adherence, the cleaning necessity determining unit 42 Since the cleaning command e is output, the operation mode is switched from the normal operation to the cleaning process, so that adhering microorganisms can be removed from the rotary disc member 12 .

As described above, the water treatment system 170 of the present embodiment controls the amount of microorganisms adhering to the rotating disc body 12 to be within an appropriate range by combining the addition of the nutrient n and the washing. Therefore, it is possible to stably and sustainably provide water quality environmental performance suitable for suppressing odor generation and removing organic matter and nitrogen.

(Modification 1 of the seventh embodiment)
In the water treatment system 170 of the seventh embodiment, when the amount of microorganisms in the water treatment tank 11 is small, the growth of microorganisms is promoted by adding a nutrient n to the raw water w, and the water treatment tank 11 An example of increasing the amount of microorganisms in the body has been described.

However, in this modified example 1, regarding the addition of the nutrient n, only so-called on/off control that controls only whether or not to add the nutrient n is performed. It is dynamically changed based on the adherence amount b of microorganisms to the disc body 12 .

In order to achieve this, in Modification 1, the nutritional supplement addition determining unit 45 adjusts the addition amount so that the larger the adhered amount b of microorganisms, the smaller the amount, and the smaller the adhered amount b of microorganisms, the larger the amount added. Then, an operation command m including the determined addition amount is output to the nutrient addition unit 91 .

In response to this, the nutrient addition unit 91 operates to add the nutrient n according to the addition amount included in the operation command m.

Further, if the discharge amount of the nutrient addition unit 91 is constant, the operation time of the nutrient addition unit 91 may be specified instead of the addition amount of the nutrient n. In this case as well, a longer operating time may be set to promote the growth of microorganisms, while a shorter operating time may be set to slowly promote the growth of microorganisms.

In this way, by dynamically determining the amount of nutrient n to be added according to the adhered amount b of microorganisms, the adhered amount b of microorganisms can be dynamically controlled so as to be kept within an appropriate range. Therefore, it is possible to stably and sustainably provide water quality environmental performance suitable for suppressing odor generation and removing organic matter and nitrogen.

In addition, in this modification, the case where the discharge amount of the nutrient addition unit 91 is constant has been described as an example. The amount of nutrient n added to the water treatment tank 11 may be controlled by setting the rotation speed.

Alternatively, the nutrient added to the water treatment tank 11 is provided by disposing a flow control valve (not shown) in the outlet side pipe of the nutrient addition unit 91 and setting the valve opening degree of the control valve according to the operation command m. You may make it control the quantity of n.

Also, the water treatment system 170 of the seventh embodiment can be implemented in combination with any of the fifth and sixth embodiments as appropriate.

(Eighth embodiment)
A water treatment system to which the water treatment method of the eighth embodiment is applied will be described.

The eighth embodiment combines activated sludge treatment.

FIG. 36 is a conceptual diagram showing a configuration example of a water treatment system to which the water treatment method of the eighth embodiment is applied.

In the water treatment system 180 illustrated in FIG. 36, the water treatment tank 11 is viewed from the side along the direction in which the raw water w flows, as in FIG.

37 is a block diagram showing a configuration example of a controller and a monitoring device in the water treatment system of the eighth embodiment; FIG.

The water treatment system 180 of the eighth embodiment, as illustrated in FIG. A blower 94 that supplies the water, a sedimentation tank 95, a sludge return pipe 97 and a discharge pipe 98 connected between the sedimentation tank 95 and the water treatment tank 11, and a sludge return part 96 provided in the sludge return pipe 97. It is configured to further include Sedimentation tank 95 can be, for example, a membrane separation tank. The discharge line 98 is connected to external equipment such as an incinerator or sludge dewatering equipment.

Further, as illustrated in FIG. 37, the controller 40 includes a sludge return determining section 46 in addition to the configuration shown in FIG.

The treated water x from the rotating disk device 10 is introduced into the biological reaction tank 92 . In the biological reaction tank 92, contaminants such as organic matter remaining in the treated water x are further decomposed by the action of activated sludge, which is a collection of microorganisms. Thereby, advanced treated water can be obtained. In the biological reaction tank 92, air bubbles are generated in the diffuser pipe 93 supplied with air from the blower 94, and the oxygen in the bubbles is used by the microorganisms in the activated sludge in the biological reaction tank to oxidize pollutants such as organic substances. decomposed.

Treated water y containing solids such as activated sludge is discharged from the biological reaction tank 92 and introduced into a sedimentation tank 95 . Solids contained in the treated water y undergo solid-liquid separation in the sedimentation tank 95 . The treated water z, which is the liquid component after solid-liquid separation, is finally discharged to a discharge destination such as a river after going through a disinfection process and the like. The solid content after the solid-liquid separation is returned to the water treatment tank 11 through the sludge return pipe 97 by the sludge return unit 96 . This returned solid content is called return sludge. Moreover, the surplus sludge after the solid-liquid separation can be discharged from the sedimentation tank 95 through the discharge pipe 98 to an external facility such as an incineration facility or a sludge dehydration facility. As a result, excess sludge can be incinerated in an incineration facility to reduce its volume, or can be dehydrated in a sludge dehydration facility.

As described in the fifth embodiment, the adhered amount estimator 41 estimates the adhered amount b of microorganisms on the rotary disc member 12 based on the received signal s, and uses the estimated adhered amount b as a cleaning requirement. The information is output not only to the rejection determination section 42 and the display section 53 but also to the sludge return determination section 46 .

The sludge return determination unit 46 outputs an operation command p to the sludge return unit 96 when the adhesion amount b is equal to or less than a predetermined value.

The sludge return unit 96 is, for example, a pump, and operates according to the operation command p from the sludge return determination unit 46 . A sludge return pipe 97 provided with a sludge return section 96 is connected to the bottom of the sedimentation tank 95 . Therefore, when the sludge return section 96 operates, the sludge obtained by the solid-liquid separation in the sedimentation tank 95 is sucked into the sludge return pipe 97 by the sludge return section 96 and transferred to the water treatment tank 11 . Since the sludge contains microorganisms, the microorganisms are returned to the water treatment tank 11 by this.

In this way, the controller 40 controls the operation of the sludge return unit 96 based on the adherence amount b of microorganisms estimated by the adherence amount estimation unit 41, and returns the sludge to the water treatment tank 11, thereby performing water treatment. Microorganisms are supplied to tank 11 .

As a result, when the amount of microorganisms is small, the amount of microorganisms can be increased by returning sludge containing microorganisms to the water treatment tank 11 .

As described above, according to the water treatment system 180 of the present embodiment, when the amount of microorganisms is small, sludge is transferred to the water treatment tank 11 based on the adhesion amount b of microorganisms adhered to the rotating disc body 12. can be controlled to return Therefore, the amount b of microorganisms adhering to the rotating disc body 12 can be appropriately maintained, and the water quality environmental performance suitable for suppressing odor generation and removing organic matter and nitrogen can be stably and continuously maintained. can be provided.

In addition, as a result, the load on the biological reaction tank 92 can be reduced. As a result, not only can the power consumption cost of the blower 94 be greatly reduced, but also the size of the bioreactor 92 can be reduced.

Therefore, when the existing biological reaction treatment process adopts a water treatment process using activated sludge such as the standard activated sludge method, by introducing the rotating disk device 10 in the front stage, energy saving and water quality It is possible to stabilize the environment.

(Modification 1 of the eighth embodiment)
In the water treatment system 180 of the eighth embodiment, when the amount of microorganisms in the water treatment tank 11 is small, by returning the sludge from the sedimentation tank 95 to the water treatment tank 11, the microorganisms in the water treatment tank 11 An example of increasing the amount of is described.

In Modification 1, regarding the addition of sludge, only the so-called on/off control that controls only whether or not to add sludge is performed, but the amount of sludge to be returned is controlled by the amount of microorganisms on the rotating disc body 12. It dynamically changes based on the adhesion amount b.

As shown in FIG. 19, the sludge return determining unit 46 determines that the amount b of microorganisms adhering to the rotary disk member 12 is equal to or less than a predetermined value u, and when the sludge returning unit 96 is operated, the smaller the adherence amount b, the more sludge The sludge return unit 96 is operated for a longer period of time so as to increase the amount of return.

The sludge return determination unit 46 outputs to the sludge return unit 96 an operation command p specifying an operation time of the sludge return unit 96 corresponding to the sludge return amount.

The sludge return unit 96 operates for a short time if the value of the sludge return amount specified by the operation command p is small, and operates for a long time if the value is large.

As a result, when the adhesion amount b is equal to or less than the predetermined value u, the smaller the adhesion amount b, the longer the sludge return unit 96 operates and the more sludge is returned to the water treatment tank 11. As a result, , more microorganisms are supplied to the raw water w.

When the adhesion amount b is larger than the predetermined value u, the cleaning instruction e is output from the cleaning necessity determination unit 42, thereby switching to the cleaning process as described above and cleaning is started. , microorganisms adhering to the rotating disc body 12 are removed.

Thus, according to this modification, the amount of sludge to be returned to the water treatment tank 11 is dynamically determined according to the amount b of the microorganisms adhering to the rotary disk 12, and the cleaning process is performed. Depending on the combination, it is possible to dynamically control the adherence amount b of microorganisms to the rotating disc body 12 so as to be kept within an appropriate range. This makes it possible to stably and sustainably provide water treatment performance such as suppression of odor generation and removal of organic matter and nitrogen.

In this modified example, the discharge amount of the sludge return unit 96 is constant. may be specified to control the amount of sludge returned to the water treatment tank 11 .

Alternatively, the amount of sludge returned to the water treatment tank 11 is determined by disposing a flow control valve (not shown) in the outlet pipe of the sludge return unit 96 and specifying the valve opening degree of the control valve in the operation command p. may be controlled.

(Modification 2 of the eighth embodiment)
FIG. 38 is a conceptual diagram showing a configuration example of a water treatment system of modification 2 of the eighth embodiment.

FIG. 39 is a block diagram showing a configuration example of a controller and a monitoring device in a water treatment system of modification 2 of the eighth embodiment.

A water treatment system 190 of Modified Example 2 of the eighth embodiment, as shown in FIG. 38, has a configuration in which the water treatment system 170 of the seventh embodiment and the water treatment system 180 of the eighth embodiment are combined. doing

Furthermore, as shown in FIG. 39, the controller 40 includes both a nutrient addition determination unit 45 shown in FIG. 35 and a sludge return determination unit 46 shown in FIG. , based on the received signal s, the adhesion amount b of the microorganisms on the rotary disk member 12 is estimated. It is also output to the agent addition determination unit 45 and the sludge return determination unit 46 .

The nutrient addition determination unit 45 determines the addition amount t of the nutrient n to be added from the nutrient storage tank 90 to the water treatment tank 11 based on the adhesion amount b, and outputs the determination to the nutrient addition unit 91 . Accordingly, the nutrient addition unit 91 can add the nutrient n of the addition amount t from the nutrient storage tank 90 to the raw water w introduced into the water treatment tank 11 .

The sludge return determination unit 46 determines the amount v of sludge to be returned by the sludge return unit 96 based on the adhesion amount b, and outputs it to the sludge return unit 96 . In response to this, the sludge return unit 96 can return the sludge of the return amount v from the sedimentation tank 95 to the water treatment tank 11 .

The rotation speed switching unit 43 determines the rotation speed per unit time of the rotary disc member 12 based on the adhesion amount b, and outputs the determined rotation speed to the motor 20 . In response to this, the motor 20 can rotate the rotary disk 12 at the determined number of rotations.

During normal operation, the controller 40 controls the amount b of microorganisms adhering to the rotating disk 12 to be within an appropriate range. Addition of nutrient n from 90, return of sludge by sludge return unit 96, and change in rotational speed of motor 20, or any two of them. , or all three may be implemented.

When performing any two, the amount of control is reduced to 1/2 of that when performed alone, and when all three are performed, the amount of control is reduced to 1/3.

For example, when adding the nutrient n from the nutrient storage tank 90 by the nutrient addition unit 91 and returning the sludge by the sludge return unit 96, when adding only the nutrient n Nutrient n is added in half the added amount t, and sludge is returned in an amount half the returned amount v when only sludge is returned.

When adding the nutrient n from the nutrient storage tank 90 by the nutrient addition unit 91, returning the sludge by the sludge return unit 96, and changing the rotation speed by the motor 20, only the nutrient n 1/3 of the amount t added in the case of adding the nutrient n, returning 1/3 of the amount v of the return amount v in the case of returning only the sludge, and the number of rotations by the motor 20 In other words, the number of rotations is changed by an amount that is ⅓ of the amount of change in the number of rotations when only the change is performed.

With such a configuration, according to the present modification, during normal operation, when the amount b of the microorganisms adhering to the rotary disk member 12 is small, the growth of the microorganisms is promoted. By suppressing the growth of microorganisms or removing the microorganisms, it is possible to flexibly control the amount b of microorganisms adhering to the rotating disc body 12 so as to always be kept within an appropriate range. As a result, it is possible to stably and sustainably provide water quality environmental performance suitable for suppressing the generation of odors and removing organic matter and nitrogen.

As described above, according to the water treatment system and water treatment method of each of the embodiments and modifications, the adhesion amount b of microorganisms adhering to a flat plate such as the rotating disc body 12 is measured by the ammeter 25, the imaging unit 71, the laser It can be estimated from information from non-contact sensors such as rangefinder 80 , photoelectric rangefinder 81 , and sonic receiver 32 . Then, it becomes possible to automatically control the operation of the water treatment system based on the estimated adhesion amount b.

This eliminates the need for an operator to visually check for adherence of microorganisms, which has been conventionally required. In addition, this automatic control can keep the adhesion amount b of microorganisms within an appropriate range, so that a stable water quality environment can be realized.

Furthermore, since the above-described non-contact sensors that provide the information necessary for estimating the adhesion amount b are almost maintenance-free, no additional maintenance work is required. This makes it possible to reduce maintenance costs, save labor, and improve operational efficiency.

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.

For example, in each of the above-described embodiments, the rotating disk 12 is used as an example of a flat plate to which microorganisms adhere, but the flat plate to which microorganisms adhere is limited to a disk-shaped flat plate such as the rotating disk 12. Instead of the rotating disk 12, a polygonal flat plate such as a quadrangle or an octagon may be used.

Claims (17)

A water treatment system that purifies the raw water with the microorganisms while rotating a flat plate on which the microorganisms are attached so that a portion of the flat plate is immersed in the raw water,
a motor that rotates a shaft to which the flat plate is attached;
a measurement unit that measures information for estimating the amount of microorganisms adhering to the flat plate;
a controller that controls the motor to rotate at a first rotation speed or at a second rotation speed higher than the first rotation speed for peeling off microorganisms adhering to the flat plate;
The controller is
estimating the amount of microorganisms adhering to the flat plate based on the information measured by the measuring unit;
determining whether the estimated amount of microorganisms has reached a predetermined value;
when it is determined that the predetermined value has been reached, controlling the motor to rotate at the second rotation speed;
The water treatment system controlling the motor to rotate at the first rotation speed when it is determined that the predetermined value has not been reached. 2. The water treatment system of claim 1, wherein said flat plate is a disk. The measurement unit is an ammeter that measures the current of the motor,
2. The water treatment system according to claim 1, wherein said controller estimates the amount of microorganisms adhering to said flat plate based on the current of said motor measured by said ammeter. The measurement unit is a pair of sound wave transmission source and sound wave receiver arranged so as to sandwich the flat plate in the plate thickness direction,
The controller obtains the spatial ratio based on the energy when the sonic wave receiver receives the sonic wave emitted from the sonic wave source, and estimates the amount of microorganisms adhering to the flat plate based on the obtained spatial ratio. The water treatment system of claim 1, wherein 2. The water treatment system according to claim 1 , wherein said controller dynamically changes said first rotation speed based on said estimated amount of microorganisms . 2. The water treatment system of claim 1 , further comprising an air diffuser for generating air bubbles to impinge on the submerged portion of said plate. The measurement unit is an imaging unit that captures an image of the flat plate,
The water treatment system according to claim 1, wherein said controller estimates the amount of microorganisms adhering to said flat plate based on the image captured by said imaging unit. The measurement unit is a rangefinder that is arranged at a predetermined location and measures the distance to the microorganism attached to the flat plate,
3. The controller estimates the amount of microorganisms adhering to the flat plate based on at least one of the image captured by the imaging unit and the distance to the microorganisms measured by the rangefinder. 7. The water treatment system according to 7. The controller is
Determining the level of anaerobicity of the microorganism based on the image captured by the imaging unit,
8. The water treatment system according to claim 7, wherein when the estimated amount of microorganisms is greater than the predetermined value or when it is determined that the degree of anaerobicity of microorganisms is high , it is determined that washing of the flat plate is necessary . 9. The water treatment system according to claim 8, wherein said rangefinder is at least one of a laser ranging sensor and a photoelectric ranging sensor. further comprising a nutrient addition unit that adds a nutrient that promotes the growth of the microorganisms to the raw water;
2. The water treatment system according to claim 1 , wherein the controller determines whether or not the nutrient adding unit needs to add the nutrient based on the estimated amount of microorganisms . 12. The water treatment system according to claim 11 , wherein said controller determines the amount of said nutrient to be added by said nutrient addition unit based on said estimated amount of microorganisms . a sedimentation basin for sedimentation of the raw water discharged from the tank in which the flat plate is arranged;
A sludge return unit for returning sludge from the raw water that has settled in the sedimentation tank to the tank,
2. The water treatment system according to claim 1 , wherein said controller determines whether or not said sludge return unit needs to return sludge based on said estimated amount of microorganisms . 14. The water treatment system according to claim 13 , wherein said controller determines the amount of sludge to be returned by said sludge returning unit based on said estimated amount of microorganisms . There are a plurality of the flat plates, and the plurality of flat plates are attached to the shaft with their end surfaces substantially parallel to each other and separated by a predetermined gap ,
The measurement unit is a pair of sound wave transmission source and sound wave receiver arranged so as to sandwich a flat plate at the position of the gap,
2. The water according to claim 1 , wherein the controller estimates the amount of microorganisms adhering to the flat plate based on the energy when the sound wave receiver receives the sound wave transmitted from the sound wave source and passed through the gap. processing system. 16. The water treatment system according to claim 15, wherein a plurality of pairs of the sound wave source and the sound wave receiver are arranged in at least one of the gaps, and the distances from the same end face of the flat plate are different for each pair. The sound wave source transmits a sound wave toward the flat plate, the sound wave receiver receives the sound wave transmitted by the sound wave source and passed through the flat plate,
16. The water treatment according to claim 15, wherein said controller has a space ratio determination unit that determines a space ratio of said flat plate to which said microorganisms are not adhered, based on the energy of the sound wave received by said sound wave receiver. system.

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