JP3235501B2 - Sludge interface measuring device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sludge interface measuring device for detecting an interface between a sludge phase and a supernatant liquid phase.
In particular, the present invention relates to an apparatus suitable for measuring a sludge interface in an anaerobic sludge tank, particularly a UASB method (upflow sludge blanket method using granular sludge).

More specifically, the present invention relates to a sludge interface measuring device which determines a sludge interface based on shape information and number information of granular sludge which changes depending on an operation state, and changes thereof.

[0003]

2. Description of the Related Art In an anaerobic sludge treatment apparatus of the UASB type, methane gas is generated in the form of colloidal fine bubbles and coarse bubbles in which the fine bubbles are associated.
The presence state of the sludge in the treatment apparatus is as follows: a sludge phase in which granular sludge having a particle size of 0.5 to 3 mm is concentrated at a concentration of 20000 to 50,000 mg / l; The crushed sludge having a particle size of 0.5 mm or less obtained by crushing the sludge has an SS (sludge) concentration of 100 to 1000 mg / l.
Can be roughly divided into the supernatant liquid phase that exists. The interface between the sludge phase and the supernatant liquid phase (sludge interface) is not constant, and is constantly developing and flowing according to the amount of generated gas and the amount of inflowing raw water.

[0004] If the sludge interface is abnormally high, granular sludge may flow out into the treated water from within the treatment equipment,
In addition, a low sludge interface leads to a small amount of sludge retained in the treatment apparatus. Therefore, in the operation management of the anaerobic sludge treatment apparatus, it is important to continuously grasp the sludge interface in the apparatus. As a method of knowing the interface height, there is a method of collecting the liquid from each depth in the tank using a sludge sampler and analyzing the sludge concentration to determine the interface height.However, sampling is performed manually. Lack of speed.

In general, as a measuring device for measuring a sludge interface in a settling tank of an activated sludge treatment apparatus or a settling tank of a coagulated sedimentation treatment apparatus, an apparatus using an ultrasonic sludge interface meter or an optical sludge concentration meter is used. . An ultrasonic interferometer is a device that emits a sound wave to a sludge interface and measures the distance from the time until the sound wave reflected at the sludge interface returns to the sludge. The optical sludge densitometer is an apparatus that determines the interface by using the fact that the amount of transmitted light differs between the sludge layer and the supernatant.

[0006]

As a result of measuring the sludge interface in an anaerobic sludge treatment apparatus using these methods, both methods were greatly affected by the generated methane gas, and could not be reliably measured. In particular, in the ultrasonic type sludge interface meter, ultrasonic waves are not normally propagated due to bubbles of generated methane gas. In addition, the optical sludge densitometer has disadvantages in that the generated fine methane gas and granular sludge are insufficiently distinguished, and errors are increased due to the influence of chromaticity of water.

The present invention has been made in view of the above problems, and provides a sludge interface measuring apparatus capable of measuring a sludge interface accurately without being affected by generated bubbles in measuring a sludge interface inside a sludge tank. With the goal.

[0008]

SUMMARY OF THE INVENTION A sludge interface measuring apparatus according to the present invention uses an imaging means for photographing a suspension, and a sludge phase and a supernatant using a neural network based on image information obtained from the imaging means. A sludge interface measurement device comprising: a determination unit for determining an interface with a liquid phase , wherein the determination unit
Makes the determination based on a histogram of lightness versus number of pixels.
Is what you do .

In order to measure the sludge interface by the sludge interface measuring device of the present invention, for example, an image of the liquid is taken by an imaging means such as a CCD camera. Based on this imaging data, it is determined using a neural network whether it is in the sludge phase or in the supernatant liquid phase. To make this determination, a number of actual images of the suspension are input in advance to the computer and the results of the determination of whether each image is in the sludge phase or in the supernatant liquid phase (this determination is Is input to the computer and trained by the computer. In the computer, a histogram of the lightness versus the number of pixels as shown in FIG. 3 is created, the correspondence between the histogram pattern and the sludge phase or the supernatant liquid phase is inductively stored, and this is stored as a learning result. At the time of the determination, it is determined based on the learning result whether the imaging point is in the sludge phase or in the supernatant liquid phase.

The imaging data at a plurality of depths can be obtained by changing the depth of the imaging means or by previously arranging a plurality of imaging means in the liquid at different installation depths.
It is determined whether each imaging point is in the sludge phase. It is determined that a sludge interface exists between the highest one of the points determined to be in the sludge phase and the lowest one of the points determined to be in the supernatant liquid phase.

[0011]

FIG. 1 is a cross-sectional view of a biological treatment tank 1 provided with an apparatus according to an embodiment of the present invention, in which a supernatant liquid phase 2 and a sludge phase 3 are provided.
And exists. Elevating device 6 provided above tank 1
The CCD camera 4 and the light projector 5 are suspended via a suspension member 7. The elevating device 6 can change the vertical position (depth) of the camera 4 and the projector 5 in water in the vertical direction, and can detect the depth to output depth information.

The lifting device 6 has a rack-and-pinion mechanism, and outputs depth information from the number of rotations of a motor for rotating the pinion; A screw mechanism for raising and lowering a screw rod by rotation, and outputting depth information from the number of rotations of a motor for rotating a nut; a winding machine for a wire for suspension; Various types such as outputting depth information from the number of rotations of the machine can be used.

The light projector 5 is provided to irradiate the inside of the tank 1 in which external light is blocked, but can be omitted when the tank 1 is provided with a lighting window or lighting.

The CCD camera 4 has a waterproof case (not shown).
Is located within. The CCD camera 4 is, for example, 2
It has 56 × 256 pixels, and outputs image data to the determination unit 8 of the signal processing device 10 and the image display device 11.

In this determination unit 8, 256 × 256
The brightness of each pixel is converted into a histogram as shown in FIG. Then, the histogram-converted data is compared with the existing learning data, and the determination in the sludge phase or the supernatant liquid phase is performed.
As a specific method of this learning and determination, for example, the following method can be cited.

First, an image previously determined to be in the sludge phase or in the supernatant liquid phase is input to a computer, and this data is converted into a histogram. Then, the average value, the deviation, the variance (or the standard deviation) of the brightness, the number of peaks (mountains) in the number of pixels (two in FIG. 3), the brightness values of each peak (for example, mode and second mode), Data is collected from the histogram for predictive variables such as the number of bottoms (valleys) of the number and the brightness value of each bottom. A large number of images and the results of determination of the sludge phase or the supernatant liquid phase of each image are input, and data of all predictive variables is collected for each image.

After collecting the data of all the predictive variables for all the images, the decision elements (square coefficient, weighting coefficient, weight coefficient, etc.) in which the data of each predictor and the judgment result (in the sludge phase or in the supernatant liquid phase) match. And the like, and the learning is terminated.

When actual image data is input based on the learning result, it is determined whether the imaging point is in the sludge phase or the supernatant liquid phase.

As shown in FIG. 2, it is determined whether the imaging point is in the sludge phase or the supernatant liquid phase based on the histogram of the brightness versus the number of pixels on the imaging screen at a certain depth. When it is determined that the imaging point is in the sludge phase, the CCD camera 4 is then moved upward by a predetermined distance, an image of the liquid is taken at that point, and the determination is performed in the same manner as described above.
The imaging point is gradually raised to a point where the result of the determination is in the supernatant liquid phase. If the determination result reaches the point in the supernatant liquid phase, the interface height determination circuit 9 determines that the sludge interface exists between that point and the highest point in the sludge phase where the determination result is. Then, a signal (interface information) is output using the intermediate level as the sludge interface position.

When it is determined that the point is in the supernatant liquid phase as a result of the analysis of the imaging data at a certain depth, the elevating device 6 is operated so as to sequentially deepen the imaging point from that point. The intermediate between the supernatant liquid phase height and the initial sludge phase height is defined as the sludge interface position.

In the above description, one CCD camera 4 is connected to the tank 1
The sludge interface is detected by changing its depth, but a plurality of CCD cameras having different installation depths may be fixed in the tank 1.

[0022]

As described above, according to the sludge interface measuring apparatus of the present invention, the suspension is imaged using a neural network .
There, whether imaging those things or supernatant phase within the sludge phase
The determination is made based on the histogram of the brightness versus the number of pixels , and the sludge interface can be measured with high accuracy without being affected by bubbles or chromaticity in the liquid.

[Brief description of the drawings]

FIG. 1A is a cross-sectional view of a biological treatment tank provided with an embodiment apparatus, and FIG. 1B is a block diagram of the embodiment apparatus.

FIG. 2 is a flowchart showing the operation of the embodiment device.

FIG. 3 is an example of a histogram of brightness versus number of pixels.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Biological treatment tank 2 Supernatant liquid phase 3 Sludge phase 4 CCD camera 5 Floodlight 6 Lifting device 7 Suspension member 8 Judgment part 9 Interface height determination circuit

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-9-21678 (JP, A) JP-A-3-112679 (JP, U) JP-A-3-13563 (JP, U) (58) Survey Field (Int.Cl. ⁷ , DB name) G01F 23/28

Claims (1)

(57) [Claims] 1. An imaging means for taking an image of a suspension, and the imaging means
Neural network based on image information obtained from means
Judgment of interface between sludge phase and supernatant liquid phase using work
And a judgment unitA sludge interface measuring device, The determination unit is based on a histogram of brightness versus number of pixels.
Characterized in that the determination is made Sludge interface meter
Measuring device.