JPH08309399A - Sludge flocculation device - Google Patents

Abstract

PURPOSE: To provide a sludge flocculation device with a flocculation state measurement controller for determining automatically and accurately the optimum adding amount of a flocculant and control automatically the sludge flocculation without being affected by the state of flocculated flocks. CONSTITUTION: This flocculation state measurement control device 4 is provided with a television camera 11 for picking up the flocculated state in a test tank 4-1 and obtain an image information, an image processing device 10 for performing the bivalent processing to the image information provided by the television camera and computing the total number of skeletons by skeleton algorithm from the bivalent processed image and a controller 4-2 for evaluating the flocculated state from the total number of computed skeletons and determining the optimum adding amount. A plurality of cycles of the feeding and throwing-away of sludge water and a flocculant into the test tank 4-1 are repeated at the time of every measurement while the amount of flocculant is varied every time to determine the optimum adding amount.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sludge flocculation apparatus for a water treatment process, and more particularly to an apparatus for automatically measuring the flocculation state of sludge and automatically adjusting the amount of flocculant added.

[0002]

2. Description of the Related Art Sludge coagulation treatment in a water treatment process is a pretreatment for efficiently removing sludge, and is a step of coagulating sedimentation by adding a coagulant to water containing sludge. If the sludge agglomeration state by this agglomeration process is good,
The water content of sludge after dehydration can be reduced. Therefore, it is important in the water treatment process to measure the agglomeration state of sludge and add an appropriate amount of a flocculant to achieve the best agglomeration state.

Conventionally, as a method for measuring the state of aggregation of such sludge, the first method of measuring the amount of colloidal charge of the dehydrated separated liquid of the aggregated sludge, or the sludge after dehydration was brought into contact with an electrode. A second method has been proposed in which the water content of sludge is directly measured from the electrolysis current at the time. However, both the above-mentioned first and second methods require a special sensor, and not only the maintenance thereof becomes a problem in an actual line, but also an appropriate method for measuring the aggregation state online. I can't say.

As a method for solving such a problem,
Japanese Patent Publication 6-614
It is proposed in Japanese Patent No. In this method, an image pickup means for picking up an image of the floc formed in the floc formation pond, a measuring means for measuring the turbidity of water in the settling pond, and an image of the floc floc can be binarized by a brightness level. Means for obtaining the average particle size of the floc group based on the obtained binarized image, and controlling the injection amount of the coagulant so that the average particle size is not more than the specified particle size and the turbidity is not more than the specified turbidity. An injection control means is provided to automate the visual evaluation of the operator.

[0005]

However, in the above-mentioned method, the distribution density of the aggregated flocs is high, and it may be difficult to evaluate an image in which the aggregated flocs are overlapped with each other.

The present invention has been made in view of such problems, and it is possible to automatically and accurately determine the optimum addition amount and automatically control sludge flocculation processing without being affected by the state of flocculation flocs. It is an object of the present invention to provide a sludge flocculation treatment device including a flocculation state measurement control device capable of performing the above.

[0007]

According to the present invention, there is provided a sludge flocculation apparatus equipped with a flocculation tank for coagulating and sedimenting sludge by adding a flocculant to sludge water containing sludge. From the supply line and the coagulant supply line, respectively, receiving a part of the sludge water and the coagulant to evaluate the coagulation state of the sludge in a small test tank, and to the coagulation tank according to the result of the evaluation. An aggregation state measurement control device for determining the optimum addition amount of the coagulant, and a coagulant flow rate control device for supplying the determined optimum addition amount of the coagulant to the aggregation tank, the aggregation state measurement control device, A television camera that obtains image information by imaging the agglomeration state of agglomerate flocs in the test tank, and the image information obtained by the television camera is binarized, and a skeleton is obtained from the binarized image. Al An image processing means for calculating the total number of skeletons by rhythm, and a control device for determining the optimum addition amount by evaluating the aggregation state from the calculated total number of skeletons, the sludge water to the test tank and the A sludge coagulation treatment device is obtained, which is characterized in that the optimum addition amount is determined by repeating the supply and disposal of the coagulant each time measurement is performed while changing the amount of the coagulant.

Further, according to the present invention, in a sludge coagulation treatment apparatus equipped with a coagulation tank for coagulating sedimentation by adding a coagulant to sludge water containing sludge, a sludge water supply line to the coagulation tank and a coagulant The sludge flocculation state is evaluated in a small test tank by receiving a part of the sludge water and the flocculant from the supply line, and the optimum addition of the flocculant to the flocculation tank is performed according to the result of the evaluation. A flocculation state measurement control device for determining the amount, and a flocculant flow rate control device for supplying the determined optimum addition amount of flocculant to the flocculation tank, the flocculation state measurement control device, in the test tank A television camera that captures image information by capturing the flocculation state of flocculation flocs, and the brightness level of each pixel is calculated from the grayscale of the original image obtained by this television camera, and the standard deviation of the brightness levels of all pixels is calculated. Image processing means, and a control device that evaluates the aggregation state from the calculated standard deviation to determine the optimum addition amount, and supplies and discards the sludge water and the flocculant to the test tank with the flocculant. It is possible to obtain a sludge coagulation treatment device characterized in that the optimum addition amount is determined by repeating the measurement each time while changing the amount.

In addition, in a sludge aggregating apparatus equipped with an aggregating tank for aggregating and sedimenting sludge by adding an aggregating agent to sludge water containing sludge, the agglomeration state of aggregating flocs in the aggregating tank is imaged to obtain image information. A television camera to be obtained, image processing means for performing a binarization process on the image information obtained by the television camera, and calculating the total number of skeletons from the binarized image by a skeleton algorithm. A controller for evaluating the aggregation state from the total number of skeletons and determining the optimum addition amount of the aggregating agent may be provided.

Further, in a sludge coagulation treatment apparatus equipped with a coagulation tank for coagulating sedimentation of sludge by adding a coagulant to sludge water containing sludge, the coagulation state of coagulation flocs in the coagulation tank is imaged to obtain image information. Obtaining a television camera, image processing means for calculating the standard deviation of the luminance level of all pixels by calculating the luminance level for each pixel from the shading of the original image obtained by this television camera, and the calculated standard deviation A controller for evaluating the aggregation state and determining the optimum addition amount may be provided.

[0011]

In the present invention, the measurement of the agglomeration state is performed in a batch process using a test tank that is much smaller than the agglomeration tank.
It takes a short time after adding the flocculant to reflect it in the flocculation state. From this fact, the addition amount of the coagulant can be repeatedly adjusted, and the optimum addition amount can be accurately determined from the result.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic diagram showing a water treatment process to which the first embodiment of the present invention is applied. Sludge water and a flocculant are supplied to a flocculation tank 1 equipped with a stirrer 1-1 from a sludge water supply line 2 and a flocculant supply line 3, respectively. A branch line 2 is provided for each of the sludge water supply line 2 and the coagulant supply line 3.
-1, 3-1 are provided, and a part of sludge water and a flocculant is supplied to the test tank 4-1 in the flocculation state measurement control device 4. Pumps 2-2 and 3-2 driven by a motor are provided in the branch lines 2-1 and 3-1 respectively, and a supply amount and a start timing are controlled by a control device 4-2 described later.
A pump 3-3 driven by a motor is provided in the coagulant supply line 3.
Is provided, and the supply amount and the start timing are controlled by the coagulant flow rate control device 5 described later. The flocculation flocs generated in the flocculation tank 1 are extracted by a pump or the like (not shown), dehydrated by the dehydrator 6, and discarded.

The agglomeration state measurement control device 4 comprises a stirrer 4-3.
In addition to the test tank 4-1 and the control device 4-2, the image processing device 10 for performing image processing described below with the television camera 11, the image from the television camera 11 and the image processing from the image processing device 10. Display device 12 for displaying results
It has and. The size of the test tank 4-1 is 10
It only needs to have a capacity of about 00 (cc), which is much smaller than the size of the coagulation tank 1 having a large capacity for several tons of water.

The operation of the aggregation state measurement control device 4 will be described with reference to FIG. In step S1, the control device 4-2 drives the pumps 2-2 and 3-2 periodically for a required time to supply a certain amount of sludge water to the test tank 4-1, and at the same time, to the sludge water. The coagulant is supplied in an amount so as to have a certain mixing ratio. In step S2, the inside of the test tank 4-1 is stirred by the stirrer 4-3. After stirring, the television camera 11
The inside of the test tank 4-1 is imaged by (step S3). In step S4, the image signal from the television camera 11 is processed, and necessary data among the processed results is displayed on the display device 1.
2 is displayed or is sent to the control device 4-2.

In step S5, the control unit 4-2 opens the discharge valve 4-4 to discard all the floc and flocs in the test tank 4-1. In step S6, it is determined whether or not the optimum amount of the coagulant has been determined by the control device 4-2, and if not determined, the mixing ratio of the coagulant is changed in step S7 and the process returns to step S1. In step S1, the control device 4-2 controls the pump 3-2 so as to obtain the changed mixing ratio. Steps S1 to S7
Is repeated until the optimum addition amount of the flocculant can be determined.

When the control device 4-2 determines the optimum addition amount of the coagulant, it sends it to the coagulant flow rate control device 5 and the display device 12 as a command value. The coagulant flow rate control device 5 controls the pump 3-3 based on the sent command value to supply the specified amount of the coagulant to the coagulation tank 1. The operator can manually input the command value displayed on the display device 12 from a key input device or the like by switching the switch S1 to the operator operation side as necessary.

As described above, the flocculation state measurement control device 4 used in the present invention adds the flocculant to a small amount of sludge water in a system separate from the flocculation tank at regular intervals, so to speak, in a batch process. The measurement of the aggregation state is repeated while changing the amount, and the peak value is appropriately determined as the optimum amount of the coagulant from the results by the processing method described later. Moreover, when the agglomerate is stationary, the image of the agglomerate that is actually occurring is
Moreover, since it is performed from a close distance, it is possible to more accurately grasp the aggregation state. Furthermore, since a problem does not occur even if a good aggregation state is not always obtained in the test tank 4-1, the search method is to increase the change amount of the coagulant at first and gradually decrease the change amount. , The optimum value can be accurately determined.

FIG. 3 is a block diagram showing the configuration of the image processing apparatus 10 of FIG. 1 in more detail. The image signal sent from the television camera 11 is stored as a digital signal in the frame memory 101, then read by the CPU 102, and the image is evaluated according to an algorithm described later. The evaluation result is displayed on the display device 12 through the display circuit 103.

When performing complicated image processing or when it is desired to shorten the processing time, a high-speed processor 104 for image processing may be added. The above image processing by the image processing apparatus 10 can be easily performed by using a personal computer.

Next, the image processing operation of the image processing apparatus 10 will be described. FIG. 4 is a diagram for explaining the image after the binarization processing performed for the preprocessing on the image of the imaged state of the aggregation floc. FIG. 4A is an image obtained after binarization processing obtained from a good floc, and the boundary of each floc is relatively easy to distinguish.
In (b), a large number of floc flocs stick to each other, making it difficult to recognize the boundaries of the flocs. A method well known in the ordinary image processing field can be used for the method of converting an original image into a binarized image, and detailed description thereof will be omitted.

In the image processing apparatus 10 according to the present invention,
The following two methods are adopted as a method that can accurately evaluate the aggregation state even when the aggregation flocs overlap.

The aggregated floc image is binarized and then skeletonized, and the total number thereof is used as an evaluation value (hereinafter referred to as a skeleton method).

The standard deviation calculated from the light and shade of the aggregated floc image is used as the evaluation value (hereinafter referred to as the standard deviation method).

The present invention is based on the following viewpoints. That is, the visual evaluation of the aggregation state by the operator is a rough one based on experience and comparison of aggregation flocs. The evaluation is performed by comprehensively judging the size and distribution of the floc, the density of the flocs inside, and the surface properties.
The basic idea of both of these evaluation methods is to quantify the aggregation state and perform a rough evaluation that matches the operator's feeling. The skeleton method and standard deviation method will be described below.

Skeleton Method First, skeleton processing will be briefly described. Skeleton processing is explained in "Introduction to Computer Image Processing" (supervised by Hideyuki Tamura, Soken Publishing). Briefly, referring to FIG. 5, a skeleton in image processing is a set of minimum necessary disk centers that can inscribe a figure and completely cover the figure. In actual image processing, a quadrangle is used instead of a circle to facilitate implementation of the algorithm.

In the example of FIG. 6, a pixel having a number is a skeleton of a white portion, and the numerical value is the number of pixels from the pixel to the boundary line with the closest black portion. The aggregation state is evaluated using this treatment method. Specifically, the total number of skeletons in the binarized image of aggregated flocs is used as the evaluation value.
In this case, the value of the skeleton (corresponding to the radius) is not considered. The meaning of this evaluation method is described below. In the binarized image (FIG. 4A) when the aggregation state is good, the number of discs (the number of skeletons) is small because there are many places where the white flocs can be covered with a large disc. However, in the worst case (Fig. 4
In case of (b), it is necessary to use many small discs and cover them up more than in the case of being good, so that the number of skeletons (centers of the discs) increases. Therefore, it is possible to evaluate the size of the aggregated flocs in consideration of the entire area of the image with the total number of skeletons. The smaller this evaluation value (total number of skeletons), the larger the aggregated floc as a whole.

In any case, the image processing apparatus 10 calculates the total number of skeletons by performing the above-described skeleton processing using the image obtained from the television camera 11, and the control device 4-2 uses this. The addition amount of the coagulant when the total number of skeletons becomes the minimum is determined as the optimum addition amount, and this is output to the coagulant flow rate control device 5.

Standard Deviation Method FIG. 7A shows an image example of a bad aggregation state, and FIG. 7B shows an image example of a good aggregation state. In FIG. 7 (a), good flocculation flocs are not formed, and a small flocculation floc is cloudy. On the other hand, in FIG. 7B, the aggregated flocs of an appropriate size are formed with a definite boundary and an appropriate density. In such a grayscale image, the larger the individual flocs are, the more visible the depth is. This depth is expressed by the brightness level of the pixel. As a matter of course, an image of poor aggregation with small aggregation flocs has a small depth, and the difference or variation in the brightness level of each pixel in the entire image is small. FIG. 8A shows FIG. 7A, and FIG. 8B shows FIG. 7B.
2 is a histogram (graph showing the number of pixels having the same brightness level). Therefore, paying attention to the brightness level of the grayscale image,
The standard deviation of the brightness level of all pixels is used as the evaluation value. The larger the evaluation value is, the larger the flock is.

The image processing apparatus 10 calculates the brightness level of each pixel from the images of FIGS. 7A and 7B obtained from the television camera 11, and calculates the standard deviation of the brightness levels of all pixels. Output as an evaluation value. Control device 4-2
Determines the addition amount of the coagulant when the standard deviation is maximum from this evaluation value as the optimum addition amount and outputs this to the coagulant flow rate control device 5.

9 and 10 are graphs showing the results of two types of image processing methods. FIG. 9 is based on the skeleton method, in which the abscissa represents the amount of the coagulant added and the ordinate represents the total number of skeletons. FIG. 10 is based on the standard deviation method, in which the horizontal axis represents the amount of the coagulant added and the vertical axis represents the standard deviation. As is clear from FIGS. 9 and 10,
The agglomerated floc changes its agglomerated state depending on the amount of the aggregating agent added. There is an optimum point in the addition amount, and the point showing the maximum evaluation value (minimum total number of skeletons, maximum standard deviation) in the graphs of FIGS. 9 and 10 indicates the optimum addition amount of the coagulant. It is understood as a point.

As described above, in the present invention, a system different from the coagulation tank is used for a small amount of sludge water at regular intervals.
So-called batch processing, by repeating the measurement of the agglomeration state while changing the addition amount of the aggregating agent in a short time, and searching for the peak value from those results, this peak value is accurately determined as the optimal amount of the aggregating agent. can do.

11 and 12 show the permeation resistance (FIG. 11), which determines the ease of draining, and the water content of the floc after flocculation (FIG. 12), as a guide for quantitatively evaluating the aggregation state. It is a graph. In each of the figures, the horizontal axis represents the amount of coagulant added. In these graphs, the smaller the value on the vertical axis, the better the aggregation state, but there is clearly an optimum point from FIGS. 11 and 12, and that point is the optimum point shown in FIGS. 9 and 10. It turns out that it almost agrees with. Therefore, the image processing result of the present invention is
It can be used as a guideline for evaluating the aggregation state, and by adjusting the amount of coagulant added to maximize the evaluation result,
Optimal control of the aggregation state is also possible.

FIG. 13 is a schematic view showing a water treatment process according to the second embodiment of the present invention. The water 42 containing sludge in the sludge tank 41 is sent to the coagulation tank 43, where the coagulant 45 in the coagulant tank 44 is added to coagulate the sludge. The coagulant 45 in the coagulant tank 44 is sent to the coagulant tank 43 by a pump 46 having an addition amount adjusting function. The flocs of flocculation in the flocculation tank 43 are drawn out of the flocculation tank 43, dehydrated by the dehydrator 47, and then discarded.

In order to measure the aggregation state online,
An image of the flocculation floc surface in the flocculation tank 43 is picked up by the television camera 11, and an output image signal thereof is supplied to the image processing apparatus 10, where the flocculation state is evaluated by the skeleton method or the standard deviation method described above. Be done. The result is displayed on the display device 12 as needed. The operator 22 looks at the result and operates the rotation speed of the pump 46 by the remote operation means 23 such as a key input device to adjust the addition amount of the coagulant 45. Further, the information of the evaluation result by the image processing device 10 is supplied to the motor control device 24, and the switch S1 can be switched to automatically control the adjustment of the addition amount of the coagulant 45 instead of the manual operation of the operator.

[0035]

As described above, according to the present invention, it is possible to automatically measure the flocculation state online without being affected by flocculation flocs in sludge flocculation treatment, and optimally from the measurement results. Since the amount of addition of such a flocculant can be automatically determined and the amount of addition can be automatically adjusted, the operator can perform optimal control of the agglomeration state without requiring many years of experience in evaluating the agglomeration state.

Further, in the flocculation state measurement control device using the test tank, since the coagulation state in the test vessel is different from the actual plant for the flocculation treatment, whether the flocculation state is good or bad is not changed. The width can be made large, and the optimum addition amount of the coagulant can be more accurately determined by shifting from the large change width to the small change width and repeating the measurement. In addition, since the image of the agglomeration state actually occurring is taken from a state where the agglomeration floc is stationary and at a close distance, the agglomeration state can be grasped more accurately. Furthermore, it can be installed in an existing water treatment plant by only performing simple piping work.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a water treatment process to which an aggregation state measurement control device according to a first embodiment of the present invention is applied.

FIG. 2 is a diagram for explaining the operation of the aggregation state measurement control device of FIG.

3 is a block diagram showing the configuration of the image processing apparatus 10 in FIG. 1 in more detail.

FIG. 4 is a schematic diagram showing a binarized image of the aggregation state of aggregation flocs for explaining the principle of the first image processing method used in the present invention.

FIG. 5 is a diagram for explaining a skeleton method used in the present invention.

FIG. 6 is a diagram for explaining the principle when image processing is performed using the skeleton method.

FIG. 7 is a diagram showing two examples of a grayscale image of aggregated flocs for explaining the principle of the second image processing method used in the present invention.

FIG. 8 is a diagram for explaining the relationship between the brightness level and the number of pixels by the standard deviation method, which is an example of image processing used in the present invention.

FIG. 9 is a graph showing the results of the first image processing method used in the present invention.

FIG. 10 is a graph showing the results of the second image processing method used in the present invention.

FIG. 11: As a guide for quantitatively evaluating the aggregation state,
It is a graph which shows the permeation resistance which determines the ease of draining.

FIG. 12: As a guide for quantitatively evaluating the aggregation state,
It is a graph which shows the water content of the floc aggregate after dehydration.

FIG. 13 is a view for explaining the outline of a sludge aggregating treatment apparatus according to the second embodiment of the present invention.

[Explanation of symbols]

 1, 43 Coagulation tank 1-1, 4-3 Stirrer 2 Sludge supply line 3 Coagulant supply line 4 Coagulation state measurement control device 4-1 Test tank 4-4 Discharge valve 6, 47 Dehydrator 11 Television camera 12 Display device 41 sludge tank 42 water containing sludge 44 coagulant tank 45 coagulant 46 pump

Claims (4)

[Claims] 1. A sludge flocculation treatment apparatus comprising a flocculation tank for adding a flocculant to sludge water containing sludge to coagulate and settle the sludge, wherein a sludge water supply line and a flocculant supply line to the flocculation tank are respectively provided. A small amount of sludge water and a coagulant is received to evaluate the coagulation state of the sludge in a small test tank, and to determine the optimum addition amount of the coagulant to the coagulant tank according to the result of the evaluation. A state measurement control device and a flocculant flow rate control device for supplying the determined optimum addition amount of the flocculant to the flocculation tank, wherein the flocculation state measurement control device is the flocculation state of flocculation flocs in the test tank. A television camera that captures image information to obtain image information, and the image information obtained by this television camera is binarized. From this binarized image, the total number of skeletons is calculated by a skeleton algorithm. An image processing means for calculating the number, and a control device for determining the optimum addition amount by evaluating the aggregation state from the calculated total number of skeletons, supply of the sludge water and the flocculant to the test tank and A sludge coagulation treatment device, characterized in that the optimum addition amount is determined by repeating a plurality of times each time measurement is performed while changing the amount of the coagulant. 2. A sludge coagulation treatment apparatus equipped with a coagulation tank for coagulating and settling sludge by adding a coagulant to sludge water containing sludge, wherein a sludge water supply line and a coagulant supply line to the coagulation tank, respectively. A small amount of sludge water and a coagulant is received to evaluate the coagulation state of the sludge in a small test tank, and to determine the optimum addition amount of the coagulant to the coagulant tank according to the result of the evaluation. A state measurement control device and a flocculant flow rate control device for supplying the determined optimum addition amount of the flocculant to the flocculation tank, wherein the flocculation state measurement control device is the flocculation state of flocculation flocs in the test tank. A television camera that captures image information to obtain image information, and an image processing unit that calculates a luminance level for each pixel from the grayscale of the original image obtained by the television camera and calculates a standard deviation of the luminance levels of all pixels. A control device for determining an optimum addition amount by evaluating a coagulation state from the calculated standard deviation, and changing the amount of the coagulant to supply and discard the sludge water and the coagulant to the test tank. However, the sludge flocculation apparatus is characterized in that the optimum addition amount is determined by repeating the measurement each time a plurality of times. 3. A sludge aggregating apparatus equipped with an aggregating tank for aggregating and sedimenting sludge by adding an aggregating agent to sludge water containing sludge, wherein image information is obtained by imaging the aggregating state of aggregating flocs in the aggregating tank. A television camera to be obtained, image processing means for performing a binarization process on the image information obtained by the television camera, and calculating the total number of skeletons from the binarized image by a skeleton algorithm. A sludge coagulation treatment apparatus, comprising: a control device that evaluates the coagulation state from the total number of skeletons to determine the optimum addition amount of the coagulant. 4. A sludge coagulation treatment apparatus comprising a coagulation tank for coagulating sedimentation of sludge by adding a coagulant to sludge water containing sludge, wherein image information is obtained by imaging the coagulation state of coagulation flocs in the coagulation tank. Obtaining a television camera, image processing means for calculating the standard deviation of the luminance level of all pixels by calculating the luminance level for each pixel from the shading of the original image obtained by this television camera, and the calculated standard deviation A sludge flocculation treatment device comprising: a control device that evaluates a flocculation state to determine an optimum addition amount.