JPH05285308A - Controller for injecting flocculant - Google Patents

Abstract

PURPOSE:To form good flocs and to prevent excessive injection of a flocculant. CONSTITUTION:The image of flocs on the outlet side of a floc forming pond 1 is picked up and the image is binarized by a recognizing means for the obtained image to recognize the flocs. The number of the flocs is calculated from the recognized data by an arithmetic unit for the number of flocs 11. When the number of the flocs obtained is the target value or more, a pump 8 is controlled by an injection controller 12 so that the injected quantity of the flocculant may be smaller than the current one.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flocculant used for forming a flocculant (hereinafter referred to as floc) by injecting a flocculant into a suspension in a water purification plant, a sewage treatment plant, or an industrial wastewater treatment plant. The present invention relates to an injection control device.

[0002]

2. Description of the Related Art FIG. 5 shows, for example, JP-A-62-241512.
It is a block diagram which shows the injection control apparatus of the conventional flocculant shown by Unexamined-Japanese-Patent No. 1 in the figure, 1 is a floc formation pond, and is divided into 3 chambers by the straightening wall which has a some hole in a wall surface. Two
Is a flock image pickup means for picking up an image of the flocs in the flock formation pond 1, 3 is an image recognition means for recognizing the picked up floc image, and 4 is a particle size distribution calculation means for calculating a particle size distribution of the flock based on the recognized image data. Reference numeral 5 is an injection amount control means for controlling the injection amount of the coagulant according to the calculation result.

Further, 6 is a rapid mixing pond for mixing raw water and a coagulant, 7 is a coagulant tank containing the coagulant, and 8 is an amount from the coagulant tank 7 corresponding to a control amount by the injection amount control means 5. A pump for supplying the coagulant to the rapid mixing basin 6, 9 is a stirrer for rapidly mixing the coagulant in the rapid mixing basin 6 with the raw water as the water to be treated, and 10 is a stirring paddle for gently stirring in the floc molding basin 1. Is.

Next, the operation will be described. First, the flock imaging means 2 installed on the exit side of the flock formation pond 1 captures a grayscale image (analog signal) of the flock. The image thus captured is input to the image recognition means 3, and the image recognition means 3 discriminates between the floc and the background (water area) by the binarization process to recognize the floc.

Next, the particle size distribution calculating means 4 calculates the particle size of each of the recognized floc regions, and the particle size distribution is calculated to calculate the logarithmic mean particle size.

Further, the injection amount control means 5 determines the coagulant injection amount to be controlled on the basis of the deviation between the calculated value of the logarithmic average particle diameter and the preset target value, and the amount of the coagulant injection amount corresponding to the coagulant injection amount is controlled. The coagulant is injected from the coagulant tank 7 into the rapid mixing basin 6 by the coagulant injection pump 8.

Here, the injected coagulant and raw water are mixed and stirred, guided to the floc formation pond 1, and gently stirred by the stirring paddle 10 to form flocs.

[0008]

Since the conventional flocculant injection control device is constructed as described above, the quality of the floc shape is evaluated based on the logarithmic average particle diameter of the floc, and the flocculant injection control is performed. However, since the purpose of floc formation is to remove suspended matter by floc sedimentation in the sedimentation basin installed after the floc formation pond 1, the logarithmic mean particle size and the concentration of suspended matter at the outlet of the sedimentation pond ( Hereinafter referred to as turbidity)
Since the relationship with the above has not been clarified, there was a problem that the injection amount control of the coagulant corresponding to the turbidity at the outlet of the sedimentation basin cannot be performed with high accuracy.

The invention of claim 1 has been made in order to solve the above-mentioned problems, and it is possible to perform good floc formation based on the turbidity at the outlet of the sedimentation basin and prevent excessive coagulant injection. The purpose is to obtain a coagulant injection control device.

It is another object of the present invention to provide a coagulant injection control device capable of controlling the coagulant injection amount with higher accuracy in accordance with the quality of raw water.

[0011]

According to a first aspect of the present invention, there is provided a flocculant injection control device which comprises a floc formation pond for forming flocs from a mixed water of a flocculant and raw water injected from a flocculant tank by a pump. A floc number calculating means, which comprises a floc image pickup means for picking up an image of the floc on the most downstream side of the flock formation pond, and an image recognition means for obtaining binarized flock corresponding data from the image pickup data obtained by the flock image pickup means. To calculate the average number of flocs in one processing screen from the floc correspondence data obtained by the image recognizing means, and the injection amount control means according to the deviation between the average number of flocs obtained by the floc number calculating means and the target value. Then, the injection amount of the coagulant by the pump is determined.

Further, in the coagulant injection control device according to the invention of claim 2, a floc formation pond for forming flocs from the mixed water of the coagulant and the raw water injected by the pump from the coagulant tank, and the floc formation. Flock imaging means for imaging the flock on the most downstream side of the pond, image recognition means for obtaining binarized flock correspondence data from the imaging data obtained by the flock imaging means, and flock correspondence data obtained by the image recognition means. From the flock number calculating means for obtaining the average flock number in one processing screen from the above, and the above-mentioned injection amount of the coagulant by the pump is determined according to the deviation between the average flock number obtained by the flock number calculating means and the target value. And a coagulant injection rate reference value calculation means for calculating a reference value of the coagulant injection rate corresponding to the water quality of the raw water. A final coagulant injection to the coagulant injection amount control means from the coagulant injection rate reference value obtained by the coagulant injection rate reference value calculation means and the output of the injection amount control means based on the average number of flocs. The amount is determined, and the pump is controlled based on the determined value.

[0013]

In the injection amount control device according to the invention of claim 1, data according to a deviation between the average number of flocks obtained from the binarized data of the flock image on the most downstream side of the flock formation pond and a preset target value. Determine the amount of coagulant injected into the raw water by

Further, the coagulant injection amount determination control means in the invention of claim 2 outputs the coagulant injection rate reference value obtained by the coagulant injection rate reference value calculation means according to the quality of the raw water and the output of the injection amount control means. Based on this, the final coagulant injection volume is determined and the pump is controlled according to this determination.

[0015]

【Example】

Example 1. An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, reference numeral 1 denotes a flock formation pond, which is divided into three chambers by a straightening wall having a plurality of holes on the wall surface. Reference numeral 2 is a flock image pickup means for picking up the flock at the most downstream exit of the flock formation pond 1, 3 is an image recognition means for recognizing the picked up flock image, and 11 is a flock for each screen based on the recognized image data. Flock number calculation means for calculating the number, and 12 is an injection amount control means for controlling the injection amount of the coagulant based on the calculated flock number.

Further, 6 is a rapid mixing tank, 7 is a flocculant tank containing a flocculant, 8 is an amount of flocculating agent supplied from the flocculation tank 7 to the rapid mixing tank 6 according to a control amount by the injection amount control means 12. The pump 9 is a stirrer for rapidly mixing the flocculant and the raw water in the rapid mixing basin 6, and 10 is a stirring paddle for gently stirring in the floc molding basin 1.

Next, the operation will be described. First, the raw water as the water to be treated is fed to the rapid mixing basin 6, and the solution of the coagulant stored in the coagulant tank 7 is injected by the pump 8.

Next, the raw water and the coagulant are agitated and mixed by the agitator 9 in the rapid mixing basin 6, and then introduced into the floc formation basin 1. In the flock formation pond 1, the raw water and the coagulant are gently stirred again by the stirring paddle 10.

Further, the flock image pickup means 2 such as an underwater camera provided at the outlet on the most downstream side of the flock formation pond 1 picks up an image of the flock at the outlet side, and a grayscale image (analog signal) of the imaged flock. ) Is input to the image recognition means 3.

Therefore, the image recognizing means 3 converts the grayscale image into a digital image by an analog / digital converter, and further binarizes it to obtain a pixel corresponding to a floc (displayed at level "1 '"). Pixels other than flock ('0
The binary image identified as “displayed at the 'level” is input to the flock count calculating means 11.

Here, the flock number calculating means 11 numbers 1, 2, 3, ... N for each of the flocks (a set of pixels represented by the 1 ′ level) existing in this binary image,
The total number of flocs n in one screen is calculated. This operation is 2
The average number of flocs N per one screen is calculated by the following formula by performing the predetermined number of processed value images, and the injection amount control means 12
Output to.

[0022]

[Equation 1]

Here, n _i is the total number of screen flock, and m is the number of processed screens. The flock binary image is obtained by processing the grayscale image (analog signal) input to the image recognition means 3 by the flock imaging means at predetermined intervals by the image recognition means 3.

Further, the relationship between the average number of flocs per screen obtained as described above and the turbidity of treated water at the outlet of the sedimentation pond installed at the rear stage of the flocculation pond 1 (turbidity at the sedimentation pond exit) is shown. As shown in FIG.

According to this, the average number of flocs fluctuates within the hatched area in the figure for the same basin outlet turbidity, but the upper limit of the average number of flocs (curve a)
Has a relation that when the turbidity at the exit of the sedimentation pond is small, it increases.

Furthermore, the relationship between the coagulant injection rate and the average number of flocs is as shown in FIG. The coagulant injection rate here is the coagulant injection rate divided by the value obtained by multiplying the raw water flow rate by the raw water turbidity.

Next, the injection amount control means 12 obtains the deviation DN (DN = N-NS) between the average number of flocs N and the target value NS, and if DN is positive, the coagulant injection amount is decreased (that is, aggregation). If the DN is negative, the coagulant injection amount is set to the current value (that is, the coagulant injection ratio is maintained as it is). To control.

In this case, the minimum value of the coagulant injection amount is set, and control is performed so that the injection amount does not become an abnormal injection below this value.

Example 2. In the above embodiment, the case where the coagulant injection amount is decreased when the average number of flocs is equal to or larger than the predetermined target value based on the current coagulant injection amount is described. However, as shown in FIG. Raw water quality detecting means 21 for detecting the raw water which is the water to be treated flowing into the mixing pond 6, and a coagulant injection rate reference value for calculating a reference value of the coagulant injection rate corresponding to the raw water quality detected here. Computing means 2
2 is provided, the injection rate reference value from the coagulant injection rate reference value calculation means 22 and the output of the injection amount control means 12 based on the average number of flocs are added in the coagulant injection amount determination control means 23, and the coagulant injection is performed. The amount may be determined.

In this way, the pump 8 can be operated according to the determination to control the coagulant injection amount into the rapid mixing basin 6, and the coagulant injection amount can be controlled without delaying the fluctuation of the raw water quality. it can. Here, the raw water quality affects the floc aggregation state such as raw water turbidity, raw water alkalinity, and raw water PH, and the reference value of the coagulant injection rate is determined as a function of these.

[0031]

As described above, according to the invention of claim 1, a floc formation pond for forming flocs from the mixed water of the coagulant and the raw water injected by the pump from the coagulant tank, and the floc formation pond. A floc image pickup means for picking up a flock image on the most downstream side of the flock, and an image recognition means for obtaining binarized flock corresponding data from the imaged data obtained by the flock image pickup means. The average floc number in one processing screen is calculated from the floc correspondence data obtained by the means, and the pump is controlled by the injection amount control means according to the deviation between the average flock number obtained by the floc number calculating means and the target value. Since it is configured to determine the above-mentioned injection amount of the flocculant, it is possible to form a good floc for removing the suspension and to prevent excessive flocculation. The effect of those injecting a can be prevented is obtained.

According to the second aspect of the present invention, the coagulant injection rate reference value calculation means is caused to calculate the reference value of the coagulant injection rate corresponding to the water quality of the raw water, and the coagulant injection rate reference value calculation is performed. From the coagulant injection rate reference value obtained by the means and the output of the injection amount control means by the average number of flocs,
Since the coagulant injection amount control means determines the final coagulant injection amount and controls the above-mentioned pump based on the determined value, the coagulant injection amount is further increased according to the water quality of the raw water. The effect that can be controlled with accuracy is obtained.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a coagulant injection control device according to an embodiment of the present invention.

FIG. 2 is a characteristic diagram showing the relationship between the turbidity of treated water on the outlet side of a floc formation pond and the average number of flocs in the present invention.

FIG. 3 is a characteristic diagram showing the relationship between the average number of flocs and the coagulant injection according to the present invention.

FIG. 4 is a configuration diagram showing a coagulant injection control device according to another embodiment of the present invention.

FIG. 5 is a configuration diagram showing a conventional coagulant injection control device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Flock formation pond 2 Flock imaging means 3 Image recognition means 7 Flocculant tank 8 Pump 11 Flock number calculation means 12 Injection amount control means 22 Flocculant injection rate reference value calculation means 23 Flocculant injection amount determination control means

Claims (2)

[Claims] 1. A floc formation pond for forming flocs from a mixed water of a coagulant and raw water, which is injected from a flocculant tank by a pump, and a flock imaging means for imaging the flocs on the most downstream side of the floc formation pond. An image recognition means for obtaining binarized flock corresponding data from the imaged data obtained by the flock image pickup means, and a flock number calculating means for obtaining an average flock number in one processing screen from the flock corresponding data obtained by the image recognition means. And an injection amount control means for determining the injection amount of the coagulant by the pump in accordance with the deviation between the average number of flocs obtained by the floc number calculation means and the target value. 2. A floc formation pond for forming flocs from a mixed water of a coagulant and raw water, which is injected from a flocculant tank by a pump, and a floc imaging means for capturing an image of the flocs on the most downstream side of the floc formation pond. An image recognition means for obtaining binarized flock corresponding data from the imaged data obtained by the flock image pickup means, and a flock number calculating means for obtaining an average flock number in one processing screen from the flock corresponding data obtained by the image recognition means. An injection amount control means for determining the injection amount of the flocculant by the pump according to the deviation between the average floc number obtained by the floc number calculation means and the target value; and a flocculant corresponding to the water quality of the raw water. Flocculant injection rate reference value calculation means for calculating a reference value of injection rate, and coagulant injection rate obtained by the flocculant injection rate reference value calculation means A final coagulant injection amount is determined from the reference value and the output of the injection amount control means based on the average number of flocs, and a flocculating agent injection amount determination control means for controlling the pump based on the determined value is used. Agent injection control device.