JPH0817891B2 - Flocculant injection amount control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a flocculant injection control device for forming and precipitating a floc of suspended matter in a water purification plant, a sewage treatment plant, or an industrial wastewater treatment plant. The present invention relates to a device for controlling the injection amount of the coagulant.

[Conventional technology]

In a fresh water plant, a flocculant is added to raw water to flocculate suspended matter to form flocs, and the flocs are sedimented and removed. That is, after injecting the coagulant in the rapid mixing pond, the flocks are formed while gently stirring in the flocks forming pond. Raw water flowing out from the floc formation pond is guided to the sedimentation pond, and sediments the flocs to remove suspended substances. Fine particles that have not settled in the settling tank are removed in the filter tank.

In this way, when the water treatment is performed, if the flocks are not formed, the clogging of the filter member will be accelerated. Conventionally, for example, as described in Japanese Patent Publication No. 59-298281,
The amount of coagulant injected is controlled based on the turbidity of raw water and the particle size and surface area of the turbidity.

On the other hand, as described in JP-A-61-64307, image recognition of the flocks in the sedimentation basin is performed to detect the formation conditions such as the size, number, and distribution of the flocks in the sedimentation basin, and the treated water amount and the coagulant injection amount are detected. Have been proposed.

[Problems to be solved by the invention]

As described in Japanese Examined Patent Publication No. 59-298281, the flocculation can be caused by temperature, turbidity, particle size, pH only by controlling the coagulant injection amount based on the turbidity of raw water and the particle size and surface area of turbidity. Moreover, since it is affected by the alkalinity and the like, it cannot be guaranteed that the flock formation can be improved. In addition, if the flocks have a large particle size but a low density, the sedimentation rate is slow,
During the sedimentation process, the micro-flocs are left behind, and the micro-floors flow into the filtration and become a load.

In Japanese Patent Laid-Open No. 61-64307, the number and size of the flock at the camera installation position in the settling basin are measured to measure the flock formation state. However, the grasp of the flock settling state is described. Absent. In addition, it is not possible to completely understand the flocculation state and the sedimentation state in the sedimentation basin simply by measuring the flocculation situation at one point in the sedimentation pond. It is not yet known how to evaluate the quality of the floc sedimentation state from the image recognition information of the floc and control the coagulant injection amount.

It is an object of the present invention to provide a flocculant injection amount control device that forms a floc with good sedimentation.

[Means for solving problems]

The purpose of the above is to recognize the floc images at multiple points in the sedimentation basin, determine the particle size distribution, and compare these to detect the flotation sedimentation state in the sedimentation basin, and control the coagulant injection amount based on this sedimentation state data. It is achieved by doing.

[Action]

According to the control device configured as described above, it is possible to extract the flocs and calculate the particle size distribution by imaging the flocs in the sedimentation basin with, for example, an industrial television camera and processing the image data of the flocks. The particle size distribution at multiple points in the sedimentation basin, that is, the floc state can be integrated to obtain the floc sedimentation state.

〔Example〕

 FIG. 1 is a diagram showing an embodiment of the present invention.

In FIG. 1, the taken raw water is led to a rapid mixing pond 20 via a landing well 10. The rapid mixing pond 20 has an agitator.
21 is provided and stirs the raw water into which the coagulant has been injected from the coagulant injector 22. In the rapid mixing pond 20, the fine particles of suspended solids become microflots by the action of the flocculant. The block formation pond 30 is provided with stirring flocculators 31A, 31B, 31C, and these stirring flocculators are rotated by stirring motors 32A, 32B, 32C. Stirring paddle 31A, 31B, 3
The space between 1C is partitioned by flow straightening walls 33A and 33B having a large number of holes. The small flocks that flowed in from the rapid mixing pond 20 were collected in the flocks forming pond 30 in the flocculator.
By being sequentially stirred by 31A, 31B, and 31C, the micro-flocks collide with each other and aggregate to form the flocks 34. The particle diameter of the flock 34 gradually increases while passing through the flock formation pond 30. Flotch in the Flotch formation pond 30
34 flows into the settling tank 40 and is removed by sedimentation. Flock 34
The supernatant water from which is removed flows into the filter basin 50. The filter pond 50
Then, the remaining fine flocks that are not removed in the sedimentation tank 40 are removed by filtration. The water that has passed through the filtration pond 50 is supplied through a drainage pond (not shown), a reservoir (not shown), and the like.

The imaging devices 100 and 200 installed in the sedimentation basin 40 convert the image of the block in the sedimentation basin into brightness information by an industrial television camera (not shown). The controllers 110 and 210 control the imaging devices 100 and 200, respectively, and transmit the brightness information to the selector 500. The selector 500 selects one of the luminance signals of the image pickup devices 100 and 200 and transmits it to the image processing device 400. or,
The selector 500 transmits the selected installation position of the imaging device in the sedimentation tank to the arithmetic device 300.

The selector 500 first selects the imaging device 100, transmits the luminance signal to the image processing device 400, and transmits the position information to the arithmetic device 300.

The image processing device 400 displays the transmitted luminance information on a monitor (not shown), and at the same time, performs image processing calculation based on the luminance information to calculate the particle size distribution of the flock and its average diameter. The calculated value is transmitted to the arithmetic unit 300. The arithmetic device 300 stores the particle size distribution and, at the same time, sends a signal to the selector 500 to switch the image pickup device from 100 to 200. The selector 500 inputs the signal of the arithmetic device 300, transmits the luminance signal of the imaging device 200 to the image processing device 400, and transmits the installation position of the imaging device 200 in the sedimentation basin to the arithmetic device 300.
The image processing device 400, based on the input luminance signal of the image pickup device 200, calculates the particle size distribution of the flocks at the position of the image pickup device 200,
The average diameter is calculated and transmitted to the arithmetic device 300. Arithmetic device 300
Determines the present flocculation state from the particle size distribution of the flocks at the positions of the imaging devices 100 and 200.

The coagulant injection machine 22 receives the sedimentation state signal calculated by the arithmetic device 300 and controls the coagulant injection amount.

Similarly, the flocculator controller 34 receives the sedimentation state signal from the arithmetic unit 300 and calculates the respective rotation speeds of the flocculator stirring motors 32A, 32B, 32C, and the flocculator stirring motors 32A, 32B, 32C are calculated. In response to the rotation speed signal, the rotations of the flocculators 31A, 31B, 31C rotate according to the rotation speed.

FIG. 2 shows a detailed configuration of the image pickup apparatus 100 described above. An industrial television camera (CCTV) 130 fixed in an airtight case 120 magnifies and recognizes an image of the floc situation in the sedimentation basin through an observation window 123 made of a transparent material such as glass. A back screen 121 is provided in order to accurately recognize the block group with high contrast. The back screen 121 is installed in front of the observation window 123 through a back screen fixing metal fitting 122 fixed to an airtight case.The back screen 121 is a dark color in order to accurately recognize a white group of flocs with high contrast. A system is preferable. Although not shown, a wiper for cleaning dirt on the surfaces of the observation window 123 and the back screen 121, or
The flush water injection device is provided in the airtight case 120.
It is desirable that a plurality of illuminating devices 140 be installed to irradiate the flocks in a multi-faceted manner to give a uniform illuminance to the flocks. The controller 110 controls the lighting device 140 and the industrial television camera 130, and transmits the luminance signal from the industrial television camera 130 to the selector 500.

 FIG. 3 shows the configuration of the image processing device 400.

The block brightness information from the selector 500 is the A / D converter 401.
Is input to Upon receiving the trigger from the timing circuit 408, the A / D converter 401 converts the luminance signal into, for example, an 8-bit digital signal. The converted digital signal is stored in the multivalued memory 402 having a capacity of, for example, 256 × 256 × 8 bits. The block image information of the multi-valued memory 402 is input to the brightness difference intensity circuit 403 as preprocessing, the brightness of the block part is emphasized, and at the same time, the background high frequency noise is cut. Based on the signal output from the brightness difference emphasizing circuit 403, the binarizing circuit 404 binarizes and extracts the block portion and stores it in the binary memory 405 having a capacity of 256 × 256 × 1 bit. That is, the luminance signal G of the pixel on the column i and the row j of the input image signals (i, j), binarized thresholds and L _t, a binary signal after B (i, j) When, The binarization circuit 404 executes the calculation of the following equation.

When G (i, j) ≧ L _t B (i, j) = 1 (1) When G (i, j) <L _t B (i, j) = 0 (2) As a result, the image signal G A pixel whose (i, j) is higher than the threshold L _t is recognized as a pixel corresponding to the block, and is set to "1" level. On the contrary, a portion whose brightness is lower than the threshold L _t is recognized as a pixel other than the block, and "0" is recognized. It becomes a level. A set of pixels represented by "1" level is recognized as a block. The particle size distribution calculation circuit 406 uses the block 2 stored in the binary memory 405.
A known image processing technique labeling process is performed on the value image, and the number of blocks and the area of each block are extracted from the connectivity. The area of each of the extracted blocks is assumed to be the same area as the circle, the circle equivalent diameter D is calculated, and the volume is calculated from the circle equivalent diameter D, so that the clock volume distribution is used as the particle size distribution. Extract and store in internal particle size distribution memory. For example, the particle size distribution memory is divided into the following 51 divisions.

D ₁ : 0.0 to 0.1 mm D ₂ : 0.1 to 0.2 mm D ₃ : 0.2 to 0.3 mm :: D ₅₀ : 4.9 to 5.0 mm D ₅₁ : 5.0 to mm The number-of-calculations counter 407 indicates that each particle size distribution calculation on one screen is completed. Is incremented, and it is determined whether or not the block image processing is completed for the number of N screens. If the number of times is less than N, the timing circuit 408 transmits a signal for instructing the generation of an A / D start trigger. At the end of N times, the N screen particle size distribution integrated data is output to the arithmetic device 300 via the input / output device 409. A / D
The converted block image signal, the multi-valued memory 402, the binarized memory 404 and the particle size distribution can be displayed on the monitor via the input / output device 409.

FIG. 4 shows the configuration of the arithmetic unit 300. The signal of the particle size distribution D _i from the image processing device 400 input to the arithmetic device 300 is stored in the particle size distribution memory 301. Representative value calculation circuit 3
02 calculates the average value D _m and standard deviation D _v of the particle size distribution of the particle size distribution memory 301 and outputs it to the judgment circuit 303. Selector 50
The installation position information of the imaging device in the sedimentation tank entered from 0 is
The normal data memory 306, which is input to the normal data memory 306, receives the position information input from the selector 500 and receives the average value D _m0 and the standard deviation D of the normal particle size distribution at that position.
_v0 is extracted to the comparison memory 307.

The determination circuit 303 compares the average diameter D _m calculated online and the normal value D _m0, and stores the deviation E ₀ in the deviation memory 304.

By performing the above-described processing on both the image pickup apparatuses 100 and 200, the deviation memory 304 displays the deviation E _{0 from} the normal value of the particle size distribution at the position of the image pickup apparatus 100 and the image pickup apparatus 2
The deviation E ₁ of the position 00 is stored. These deviations E ₀ , E ₁
Is sent to the sedimentation state detection circuit 305 and compared to the normal sedimentation state, “settlement is slow”, “sedimentation is fast”, and “normal”.
It is divided into two signals and sent to the coagulant injector 22 and the flocculator controller 34.

 The sedimentation state signal will be described with reference to FIG.

The flock formed in the flock formation pond 30 is sent to the settling pond 40 and settles. The shaded area 41 represents the sedimented flocks. The term "floc sedimentation normal" means that the flocks are submerged to the size of the sedimentation tank, that is, when almost all the flocs reach the sedimentation tank outlet, they are settled to a depth that does not flow out of the outlet. It is curve C0. On the other hand, in the case of the premature curve C2 in which the sedimentation is too fast, the size of the sedimentation basin is not utilized and the sedimentation ends midway, so there is too much margin compared to the sedimentation state of the normal curve C0. In order to make the best use of the condition of the settling basin 40, the coagulant can be reduced so as to approach the curve C0 in the normal condition. If the sedimentation is too slow, the flocs will flow out on the delay curve C1, so the coagulant is increased or the flocculator rotation speed is decreased to bring it closer to the normal curve C0.

The imaging device has a structure that allows the installation position to be moved remotely in two dimensions, vertically and horizontally from the installation position, and if the data at the point that is the point of each water treatment plant and its vicinity is increased, more accurate sedimentation will occur. Data is obtained.

FIG. 6 is a chart showing the relationship between the coagulant injection amount P and the sedimentation state. Injector 22 sends a "slow sedimentation" signal
When the signal is received, the injection amount P is increased, and conversely, when the signal “the sedimentation state is fast” is received, the injection amount P is decreased. The maximum value P _max and the minimum value p _min are set for the injection amount P,
Prevent abnormal injection.

FIG. 7 is a chart showing the relationship between the flocculator rotation speed N and the sedimentation state. The flocculator controller 34 is
When the signal of "the sedimentation state is too slow" is received, the rotation speeds N (A), N (B), N of the stirring motors 32A, 32B, 32C
Operate so that (C) becomes smaller. On the contrary, when the signal "the sedimentation state is excessively fast" is received, the agitating motors 32A, 32B, and 32C are operated so as to increase the rotational speed in order to reduce the block. The upper limit of the rotation speed of the stirring motor is M
_{Set max} and lower limit N _min . If the flocculator is a tapered type, the rotation speed N (A), N
(B), N (C) ratio is manipulated. In this way, the stirring motors 32A, 32B, 32C operate the rotation speeds of the flocculators 31A, 31B, 31C, the stirring force in the flocks forming pond is controlled, and stable flocks are always formed.

〔The invention's effect〕

According to the present invention, the sedimentation state of the flocs is measured by recognizing a plurality of flocs by an image, and the increase / decrease of the coagulant injection amount is controlled. Therefore, the coagulant injection amount can be controlled while directly judging the quality of the sedimentation state, which is the purpose of actual floc formation, so that stable flocculation can be performed.

The present invention can also be applied to coagulant injection control in coagulation processes other than water purification plants. For example, in a sewage treatment plant, a process of injecting a coagulant into activated sludge to improve sedimentation, a refining process by injecting a coagulant in sludge treatment,
Also, it can be used for a pulverized coal granulation process and the like.

[Brief description of drawings]

FIG. 1 is a system diagram showing one embodiment of a flocculant injection amount control device according to the present invention, FIGS. 2 to 4 are explanatory views of constituent parts of the above-mentioned embodiment, and FIGS. It is a chart for explaining the operation effect of the example. 20 ... Rapid mixing pond, 22 ... Coagulant injection device, 30 ... Flot formation pond, 31A, 31B, 31C ... Floquilator, 32A, 32
B, 32C …… Mixing motor, 100,200 …… Imaging device, 400…
… Image processing device, 300… Computing device.

Claims (1)

[Claims] 1. A raw water treatment plant provided with a means for injecting a flocculant into raw water, and provided with a flocks forming pond for forming flocs in a substance which has been flocculated and suspended, and a sedimentation pond for settling the flocs. In a), an imaging device is provided at each of a plurality of locations in the sedimentation basin, and b) means for converting an image of the flock obtained by the imaging device into luminance information, and c) a block from the luminance information. D) means for calculating the particle size distribution of the flock based on the flock image information at each of the plurality of points, and e) a means for detecting the flot sedimentation state, and e) based on the sedimentation state, And a means for controlling the coagulant injection amount of the coagulant injection device.