JP3136554B2 - Sludge coagulation equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

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

Conventionally, as a method for measuring the state of coagulation of such sludge, a first method of measuring the amount of colloidal charge of a dewatered separated liquid of coagulated sludge, or an electrode is brought into contact with sludge after dewatering. A second method for directly measuring the water content of sludge from the electrolysis current at the time has been proposed. However, each of the first and second methods requires a special sensor, and maintenance of the actual line is not only a problem, but also an appropriate method for online measuring the aggregation state. I can't say.

[0004] As a method of solving such a problem,
The method of evaluating the state of aggregation by image processing is described in Japanese Patent Publication No. 6-614.
No. 10 has proposed this. In this method, an imaging unit that captures an image of the flocculated floc formed in the flocculation pond, a measuring unit that measures the turbidity of water in the sedimentation pond, and a binarization of the flocculated floc image based on the brightness level can be performed. Means for determining the average particle size of the flocculated floc group based on the obtained binarized image, and controlling the injection amount of the flocculant such that the average particle size is equal to or less than the specified particle size and the turbidity is equal to or less than the specified turbidity. An injection control unit is provided to automate the visual evaluation of the operator.

[0005]

However, in the above method, the distribution density of the aggregated flocs is high, and it may be difficult to evaluate an image in which the aggregated flocs overlap.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and it is an object of the present invention to automatically and accurately determine an optimum amount of addition and to automatically control a sludge flocculation treatment without being affected by the state of flocculated floc. It is an object of the present invention to provide a sludge coagulation treatment device provided with a coagulation state measurement control device capable of performing the above-described processes.

[0007]

According to the present invention, there is provided a sludge flocculation treatment apparatus provided with a flocculation tank for flocculating and settling sludge by adding a flocculant to sludge water containing sludge. While receiving a part of the sludge water and the flocculant from the supply line and the flocculant supply line, respectively, the sludge flocculation state is evaluated in a small test tank. An aggregation state measurement control device that determines an optimal addition amount of the aggregation agent, and an aggregation amount flow control device that supplies the aggregation amount of the determined addition amount to the aggregation tank, wherein the aggregation state measurement control device includes: A television camera that obtains image information by imaging the state of aggregation of flocculated flocs in the test tank, and performs binarization processing on the image information obtained by the television camera; Al Image processing means for calculating the total number of skeletons by rhythm, and a control device for evaluating the aggregation state from the calculated total number of skeletons and determining an optimal addition amount, the sludge water to the test tank and the A sludge flocculation treatment apparatus is obtained, wherein the supply and disposal of the flocculant are repeated a plurality of times each time the measurement is performed while changing the amount of the flocculant, thereby determining the optimum addition amount.

[0008]

In a sludge flocculation treatment apparatus provided with a flocculation tank for flocculating and settling sludge by adding a flocculant to sludge water containing sludge, an image of the flocculation state of flocculated flocs in the flocculation tank is taken to obtain image information. A television camera to be obtained, image processing means for performing binarization processing on image information obtained by the television camera, and calculating the total number of skeletons from the binarized image by a skeleton algorithm. A control device may be provided that evaluates the state of aggregation from the total number of skeletons and determines the optimal addition amount of the aggregating agent.

[0010]

[0011]

According to the present invention, the coagulation state is measured in a batch process using a very small test tank compared to the coagulation tank.
After adding the flocculant, the time until it reflects on the flocculation state is short. From this, the addition amount of the coagulant is 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 from a sludge water supply line 2 and a flocculant supply line 3 to a flocculation tank 1 provided with the stirrer 1-1. Each of the sludge water supply line 2 and the flocculant supply line 3 has a branch line 2
-1, 3-1 are provided, and a part of the sludge water and the coagulant is supplied to the test tank 4-1 in the coagulation state measurement control device 4. The branch lines 2-1 and 3-1 are provided with motor driven pumps 2-2 and 3-2, respectively, and the supply amount and the start timing are controlled by a control device 4-2 described later.
The coagulant supply line 3 has a motor driven pump 3-3.
Is provided, and the supply amount and the start timing are controlled by the coagulant flow control device 5 described later. The flocculated floc generated in the flocculation tank 1 is extracted by a pump or the like (not shown), dehydrated by the dehydrator 6, and disposed of.

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

The operation of the coagulation state measurement control device 4 will be described with reference to FIG. In step S1, the pumps 2-2 and 3-2 are periodically driven by the control device 4-2 for a necessary period of time to supply a fixed amount of sludge water to the test tank 4-1. The coagulant is supplied in such an amount that the mixing ratio is determined. In step S2, the inside of the test tank 4-1 is stirred by the stirrer 4-3. After stirring, the television camera 11
To image the inside of the test tank 4-1 (step S3). In step S4, the image signal from the television camera 11 is processed, and necessary data of the processing result is displayed on the display device 1.
2 or send it to the control device 4-2.

In step S5, the discharge valve 4-4 is opened by the control device 4-2, and all flocculated flocs and water in the test tank 4-1 are discarded. In step S6, it is determined whether or not the optimal amount of the coagulant has been determined in the control device 4-2. If not, 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 optimal amount of the coagulant to be added can be determined.

When the control device 4-2 determines the optimum amount of the coagulant to be added, it sends this to the coagulant flow control device 5 and the display device 12 as a command value. The coagulant flow control device 5 controls the pump 3-3 based on the sent command value to supply a 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 the key input device or the like by switching the switch S1 to the operator operation side as needed.

As described above, the coagulation state measuring and controlling device 4 used in the present invention uses a system separate from the coagulation tank to add a coagulant to a small amount of sludge water at regular intervals, that is, in a batch process. The measurement of the coagulation 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. In addition, the imaging of the actual agglomerated state is performed while the agglomerated body is stationary,
In addition, since the measurement is performed from a close distance, the aggregation state can be more accurately grasped. Further, since no problem occurs even if a good coagulation state is not always obtained in the test tank 4-1, a search method is used in which the change amount of the coagulant is initially increased and the change amount is gradually reduced. , The optimum value can be determined accurately.

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 out by the CPU 102, and the image is evaluated according to an algorithm described later. This evaluation result is displayed on the display device 12 through the display circuit 103.

When performing complicated image processing or reducing the processing time, a high-speed processor 104 for image processing may be added. The above-described image processing by the image processing apparatus 10 can be easily performed even by using a personal computer.

Next, an image processing operation by the image processing apparatus 10 will be described. FIG. 4 is a diagram for explaining an image after binarization processing performed for preprocessing on an image obtained by capturing the aggregation state of the aggregation flocs. FIG. 4 (a) is an image after binarization processing obtained from good aggregated flocks, and the boundary of each aggregated floc is relatively easy to determine.
In (b), a large number of aggregated flocks are stuck together, and it is difficult to recognize the boundaries of each aggregated floc. Note that a method of converting the original image into the binarized image can use a technique well known in the ordinary image processing field, and thus a detailed description is omitted.

In the image processing apparatus 10 according to the present invention,
The following two methods are employed as a method for accurately evaluating the state of aggregation even when the aggregated flocks overlap.

A skeleton process is performed on the aggregated floc image after the binarization process, and the total number thereof is used as an evaluation value (hereinafter, referred to as a skeleton method).

A standard deviation calculated from the density of the aggregated floc image is used as an evaluation value (hereinafter, referred to as a standard deviation method).

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

Skeleton Method First, skeleton processing will be briefly described. Skeleton processing is described in "Introduction to Computer Image Processing" (supervised by Hideyuki Tamura, published by Soken). Briefly, with reference to FIG. 5, a skeleton in image processing is a set of minimum necessary disk centers that can inscribe a graphic and cover the graphic. In actual image processing, a square is used instead of a circle in order to easily realize 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 that pixel to a boundary line with the nearest black portion. The aggregation state is evaluated using this processing method. Specifically, the total number of skeletons in the binarized image of the aggregated flocs is used as the evaluation value.
In this case, the value (corresponding to the radius) of the skeleton is not considered. The meaning of this evaluation method will be described below. In the binarized image (FIG. 4 (a)) in the case where the aggregation state is good, the number of disks (the number of skeletons) is small because there are many places where the white floc portion can be covered with a large disk. However, if it is bad (Fig. 4
In (b)), the number of skeletons (the center of the disk) increases because the small disk needs to be covered and used more than in the good case. Therefore, it is possible to evaluate the size of the aggregated floc in consideration of the entire image area by the total number of skeletons. The smaller this evaluation value (the total number of skeletons) is, the larger the aggregate floc is.

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 apparatus 4-2 determines the total number of skeletons. The addition amount of the coagulant when the total number of the skeletons is minimized is determined as the optimum addition amount, and this is output to the coagulant flow control device 5.

Standard Deviation Method FIG. 7A shows an example of an image in a bad aggregation state, and FIG. 7B shows an example of an image in a good aggregation state. In FIG. 7 (a), good flocculated flocs are not formed, and small flocculated flocs are turbid. On the other hand, in FIG. 7 (b), the aggregated flocs of an appropriate size are formed at an appropriate density with a clear boundary. In such a grayscale image, the larger the individual flocs, the more the depth can be seen. This depth is represented by the luminance level of the pixel. As a matter of course, the image of the cohesion failure having a small coagulation floc has a small depth, and the difference and the variation in the brightness level of each pixel in the entire image are small. FIG. 8A shows FIG. 7A, and FIG. 8B shows FIG. 7B.
(A graph showing the number of pixels at the same luminance level). Therefore, paying attention to the brightness level of the grayscale image,
The standard deviation of the luminance levels of all pixels is used as the evaluation value. The larger the evaluation value, the larger the floc.

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

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

As described above, in the present invention, a small amount of sludge water is separated from the coagulation tank by a separate system at regular intervals.
In other words, the measurement of the coagulation state is repeated in a short time while changing the amount of coagulant added in batch processing, and the peak value is searched for from these results, and this peak value is accurately determined as the optimum amount of coagulant. can do.

FIGS. 11 and 12 show the permeation resistance (FIG. 11) and the water content of the flocculated floc after dehydration (FIG. 12), respectively, as a guide for quantitatively evaluating the flocculation state. It is a graph. In each of the figures, the abscissa indicates the amount of the coagulant added. In these graphs, the smaller the value on the vertical axis, the better the cohesion state, but there is clearly an optimum point from FIGS. 11 and 12, which is the optimum point shown in FIGS. It turns out that it almost matches. Therefore, the image processing result of the present invention is:
It becomes one measure to evaluate the coagulation state, and by adjusting the coagulant addition amount to maximize the evaluation result,
Optimal control of the aggregation state is also possible.

FIG. 13 is a schematic diagram showing a water treatment process according to a second embodiment of the present invention. The water 42 containing the 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 coagulation tank 43 by a pump 46 having an addition amount adjusting function. The flocculated flocs flocculated 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 state of aggregation online,
An image of the surface of the flocculated floc in the flocculation tank 43 is captured by the television camera 11, and the output image signal is supplied to the image processing device 10, where the evaluation of the flocculation state is performed by the skeleton method or the standard deviation method described above. It is. The result is displayed on the display device 12 as needed. The operator 22 adjusts the amount of the coagulant 45 by operating the rotation speed of the pump 46 by using the remote operation means 23 such as a key input device while observing the result. Further, information on the evaluation result by the image processing apparatus 10 is supplied to the motor control device 24, and the adjustment of the addition amount of the flocculant 45 can be automatically controlled by switching the switch S1 instead of the manual operation of the operator.

[0035]

As described above, according to the present invention, it is possible to automatically evaluate the state of flocculation on-line without being affected by flocculation floc in the sludge flocculation treatment. Since the addition amount of the coagulant can be automatically determined and the addition amount can be automatically adjusted, the operator can perform the optimal control of the coagulation state without requiring many years of experience in evaluating the coagulation state.

Further, in the coagulation state measuring and controlling apparatus using the test tank, since the quality of the coagulation state in the test tank does not matter in a separate system from the actual plant of the coagulation treatment, the addition of the coagulant per one time is changed. The width can be made large, and by repeating the measurement while shifting from the large change width to the small change width, the optimum amount of the coagulant to be added can be determined more accurately. In addition, since the imaging of the actually occurring aggregation state is performed from a close distance with the aggregation floc stationary, the aggregation state can be grasped more accurately. Furthermore, even an existing water treatment plant can be installed simply by performing simple piping work.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a water treatment process to which a coagulation 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 coagulation state measurement control device of FIG.

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

FIG. 4 is a schematic diagram showing a binarized image of an aggregated floc to explain the principle of a 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 of performing image processing using a skeleton method.

FIG. 7 is a diagram showing two examples of grayscale images 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 a relationship between a luminance level and the number of pixels by a standard deviation method which is an example of image processing used in the present invention.

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

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

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

FIG. 12 shows a guideline for quantitatively evaluating the aggregation state.
It is a graph which shows the water content of the aggregation floc after dehydration.

FIG. 13 is a view schematically illustrating a sludge aggregation treatment apparatus according to a second embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION 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 (2)

(57) [Claims] 1. A sludge flocculation treatment apparatus comprising a flocculation tank for adding a flocculant to sludge water containing sludge to flocculate and settle sludge, wherein a sludge water supply line and a flocculant supply line to the flocculation tank are The coagulation state is evaluated by receiving a part of the sludge water and the coagulant, and evaluating the coagulation state of the sludge in a small test tank, and determining the optimal addition amount of the coagulant to the coagulation tank according to the result of the evaluation. A state measurement control device, and a flocculant flow rate control device that supplies the determined optimum addition amount of the flocculant to the flocculation tank, wherein the flocculation state measurement control device is a flocculation state of the flocculation floc in the test tank. A television camera that obtains image information by imaging the image, and performs a binarization process on the image information obtained by the television camera, and calculates a total number of skeletons from the binarized image by a skeleton algorithm. Image processing means for calculating the number, comprising a controller for evaluating the aggregation state from the calculated total number of skeletons and determining the optimal addition amount, supply of the sludge water and the flocculant to the test tank and A sludge flocculation treatment apparatus characterized in that the disposal is repeated a plurality of times while measuring the amount of the flocculant while changing the amount of the flocculant, thereby determining the optimum addition amount. 2. A method of adding a flocculant to sludge water containing sludge.
Sludge coagulation treatment equipment equipped with coagulation tank for coagulating sedimentation of mud
In this case, an image is taken by capturing the state of aggregation of the aggregation flocs in the aggregation tank.
A television camera for obtaining information and this television camera
Performs binarization processing on the image information obtained by the camera.
From this binarized image using the skeleton algorithm
Image processing means for calculating the total number of skeletons;
The aggregation state was evaluated from the total number of skeletons
And a control device for determining the optimal amount of
Sludge coagulation treatment equipment.