KR20110057036A - Apparatus and method for measuring depth of sludge - Google Patents

Abstract

PURPOSE: A sludge depth measurement system and method are provided to accurately measure sludge depth based on the wave reflected off floating members on the surface of sludge without need of controlling the intensity of waves. CONSTITUTION: A sludge depth measurement system comprises a measuring unit(40) and floating members(50). The floating members are floated in the boundary between a mixed liquid layer(20), in which water and fine sludge are mixed, and a sludge layer(30). The measuring unit is installed on the water surface in a precipitation tank(10) and emits wave of specific frequency to measure sludge depth based on waves reflected off the floating members.

Description

Apparatus and Method for measuring depth of sludge

The present invention relates to a sludge depth measuring apparatus and method, and more particularly to a technique for measuring the depth of the sludge by using the reflected wave reflected from the floating body floating on the upper surface of the sludge layer.

In general, wastewater containing organic pollutants, nitrogen, and phosphorus depletes dissolved oxygen in the water, destroying the aquatic ecosystem, and eutrophicating the water in lakes and reservoirs. Therefore, in order to prevent water pollution in rivers, contaminants and organic nutrients contained in the waste water should be removed before they enter the body of the river or the like.

As a treatment method of wastewater treatment facility to remove this, many biological treatment methods which are excellent in economics are applied. Among the biological treatment methods, organic materials using microorganisms such as activated sludge method and advanced treatment are removed, but they are grown in the process of removing organic materials. Microorganisms are generated as waste sludge.

As a representative biological treatment method, activated sludge method grows as microorganisms ingest and decompose organic matter in wastewater and proceed to nitrification as waste water is continuously injected into aeration tank. As a result, some of the precipitate is returned to the aeration tank in the form of activated sludge, and some excess sludge is discharged and disposed of, so that the amount of microorganisms in the aeration tank is maintained at an appropriate level to remove nitrogen, phosphorus, etc. together with organic matter decomposition in the wastewater.

Here, in the final sedimentation tank, a flocculant is added to quickly settle the suspended sludge, and the sludge depth measurement may be specified because the optimum return and discharge time can be specified only when the depth of sludge formed in the final sedimentation tank can be accurately measured. It is a very important parameter in the treatment plant.

Currently, the method of measuring the depth of sludge includes a method of measuring by using physical components such as a frequency measuring method using ultrasonic waves, an optical measuring method using light such as an LED, and a method of attaching a sensor to a single line of a weight. Measuring method.

However, these methods have a lot of interference phenomena in measuring the sludge depth according to the water quality of the final settling tank has a disadvantage in that the accuracy and reliability are much lower.

For example, in the case of the frequency measuring method, accurate measurement is difficult because a frequency of sufficient intensity cannot be received due to interference caused by fine sludge existing between the upper surfaces of the sludge under the water surface. In order to overcome this, the intensity of the radiating frequency can be increased, but in this case, there is another problem that the sludge upper surface cannot be reflected and transmitted.

In addition, in the method of installing the parts of the measuring device installed in water, the sludge is stuck to the parts, the accuracy is lowered, there is a problem that the use is limited due to the inconvenience, such as frequent cleaning of the parts required.

Accordingly, it is an object of the present invention to provide an apparatus and method capable of accurately and reliably measuring the depth of sludge deposited in a final sedimentation tank of a sewage treatment plant or wastewater treatment plant.

The above object is applied to the activated sludge treatment system of the sewage treatment plant or wastewater treatment plant, the measuring unit is installed on the water surface in the final sedimentation tank; And a floating body floating at a boundary between the mixed liquid layer and the sludge layer in which water and fine sludge are mixed, wherein the measuring unit emits a wave having a predetermined frequency, and the sludge depth is based on the reflected wave reflected from the floating body. It is achieved by the sludge depth measuring device to measure.

Preferably, the floating body may have a specific gravity of 1.03 to 1.10 based on water, and may be made of plastic, metal, or nonmetallic material in a thin plate or membrane structure of circular, square or hexahedron, and a plurality of unit floats may be formed in the bridge. It may have a structure that is connected to each other by.

Preferably, the floating body may be plated on an outer surface thereof.

Preferably, the measuring unit, a wave generator for emitting a wave (wave) to measure the sludge depth; A detector for detecting a reflected wave emitted from the wave generator and reflected from the floating body and outputting a current value; And an arithmetic unit that calculates the sludge depth using a predetermined arithmetic expression based on the current value output from the detector.

Here, the wave radiated from the wave generator includes sound waves, ultrasonic waves, infrared rays, ultraviolet rays, or lasers, and may be selected according to the type of liquid in the mixed liquid layer.

The above object is applied to an activated sludge treatment system of a sewage treatment plant or a wastewater treatment plant, and radiating a wave having a predetermined frequency from a final sedimentation tank to a measuring unit installed above the water surface; Receiving, by the measuring unit, the reflected wave reflected from the floating body in which the radiated wave floats at the boundary between the mixed liquid layer and the sludge layer in which water and fine sludge are mixed; And calculating, by the measuring unit, the sludge depth based on the received reflected wave based on a predetermined equation.

According to the above structure, the sludge depth is calculated based on the reflecting plate reflected from the floating body without adjusting the intensity of the emitted wave, so that the accuracy and reliability of the measurement are high despite the change of the measurement parameter according to the environment.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 shows a sludge depth measuring apparatus according to an embodiment of the present invention, Figure 2 is a block diagram showing the configuration of a measuring unit.

Referring to Figure 1, the final settling tank 10 is provided with a measuring unit 40, it is installed to be located above the water surface. The number of measurement units 40 installed in the final settling tank 10 is not particularly limited.

In addition, a float 50 exists at the boundary between the mixed liquid layer 20 in which the fine sludge and water are mixed and the sludge layer 30 in which the sludge is deposited. In other words, the float 50 floats on the upper surface of the sludge layer 30.

To this end, the float 50 may have a specific gravity of about 1.03 to 1.10 based on water, and may be made of a plastic, metal, or nonmetallic material in a circular or square or hexahedral thin plate or membrane structure.

Figure 3 is an example of the shape of the float 50 applied to the present invention, and has a floating capacity in a way that a plurality of rectangular or circular unit floats are connected to each other by a bridge, the rectangular float in a circular arrangement ( 51), a circular float 52 in a circular arrangement, or a square float 53 in a linear arrangement.

Here, the overall shape of the floating body 50 and the shape and number of unit floating bodies are not limited to the example of FIG. 3 and various modifications are possible. In addition, each of the floats 51, 52, 53 may be connected to each other by a string or the like.

Preferably, the surface of the float 50 may be plated so that the sludge does not stick.

Referring to FIG. 2, the measuring unit 40 includes a calculation unit 41, a wave generator 43, and a detection unit 42.

The wave generator 43 emits waves to measure the sludge depth, and the emitted waves include sound waves, and ultrasonic waves, infrared rays, ultraviolet rays, lasers, etc. are appropriate according to the type of liquid in the mixed liquid layer 20. Can be chosen.

The detector 42 detects the reflected wave radiated from the wave generator 43 and reflected from the floating body 50 and outputs a current value.

In addition, the calculation unit 41 calculates the sludge depth based on a preset calculation formula based on the current value output from the detection unit 42.

Hereinafter, the operation of the sludge depth measuring device having the above structure will be described.

First, for example, the ultrasonic wave is radiated from the wave generator 43 of the measuring unit 40 at a predetermined intensity. Here, the intensity at which the ultrasonic waves are radiated, unlike the prior art, does not need to be considered at all whether the sludge layer 30 is transmitted. This is because the ultrasonic waves emitted from the measuring unit 40 use only the reflected waves reflected from the floating body 50 without minding that they are reflected from the upper surface of the sludge layer 30.

Ultrasonic waves emitted from the wave generator 43 are reflected by the floating body 50 floating on the upper surface of the sludge layer 30, and then pass through the mixed liquid layer 20 in which water and fine sludge are mixed. It is input to the detection part 42.

Here, the ultrasonic waves that do not hit the floating body 50 is passed through the sludge layer 30 is extinguished, and the ultrasonic waves reflected by the mixed liquid layer 20 is high enough even in the fine sludge mixed with the measuring unit 40 Reach reliably

The detector 42 detects the ultrasonic waves reflected from the floating body 50 and outputs a current value corresponding thereto.

Subsequently, the calculator 41 calculates the sludge depth from the current value using a preset calculation function and transmits the sludge depth to the controller (not shown).

When the controller determines that the sludge depth has reached the preset sludge depth, the valves 11 and 12 are opened, the pumps 13 and 14 are driven to convey the sludge to the aeration tank, and the excess sludge is discharged.

In the above description, the embodiment of the present invention has been described, but various changes can be made at the level of those skilled in the art. Therefore, the scope of the present invention should not be construed as being limited to the above embodiment, but should be interpreted by the claims described below.

1 shows a sludge depth measuring apparatus according to an embodiment of the present invention.

2 is a block diagram showing the configuration of the measuring unit 40.

3 is an example of the shape of the float 50 applied to the present invention.

Claims (7)

Applied to activated sludge treatment system of sewage treatment plant or wastewater treatment plant A measuring unit installed at the top of the water in the final settling tank; And It includes a float floating on the boundary between the mixed liquid layer and the sludge layer mixed with water and fine sludge, The measuring unit emits a wave having a predetermined frequency, the sludge depth measuring apparatus, characterized in that for measuring the sludge depth based on the reflected wave reflected from the floating body. The method according to claim 1, The sludge depth measuring device, characterized in that the float has a specific gravity of 1.03 to 1.10 based on water. The method according to claim 2, The floating body is made of a plastic, metal or non-metallic material in the form of a thin plate or membrane of a circular, square or hexahedron, the sludge depth measuring apparatus characterized in that a plurality of unit floating body is connected to each other by a bridge. The method according to claim 2 or 3, The sludge depth measuring device, characterized in that the outer surface is plated. The method according to claim 1, The measuring unit, A wave generator for emitting a wave to measure the sludge depth; A detector for detecting a reflected wave emitted from the wave generator and reflected from the floating body and outputting a current value; And Sludge depth measuring device, characterized in that it comprises a calculation unit for calculating the sludge depth using a predetermined calculation formula based on the current value output from the detection unit. The method according to claim 1 or 5, The wave includes a sound wave, ultrasonic waves, infrared rays, ultraviolet rays, or laser, the sludge depth measuring apparatus, characterized in that selected according to the type of liquid in the mixed liquid layer. Applied to activated sludge treatment system of sewage treatment plant or wastewater treatment plant Radiating a wave having a predetermined frequency from a final settling tank to a measuring unit installed above the water surface; Receiving, by the measuring unit, the reflected wave reflected from the floating body in which the radiated wave floats at the boundary between the mixed liquid layer and the sludge layer in which water and fine sludge are mixed; And And measuring, by the measuring unit, the sludge depth based on the received reflected wave based on a predetermined equation.

Images