JPS604122Y2 - Detector for activated sludge concentration measurement device in aeration tank - Google Patents

Description

[Detailed description of the invention] The method for measuring activated sludge concentration using light utilizes attenuation when light is transmitted and scattered by activated sludge.

The present invention relates to a detector for this concentration measuring device.

The figure shows an example of a detector for an activated sludge concentration measurement device using light, which includes a light source section 1 installed to project light into the activated sludge of the subject using a light source lamp, and a light source section 1 with this light source section inside. It consists of two light receiving sections 2 which are arranged at different distances from the light source section and receive the light transmitted through the subject and the scattered light projected from the light source section and convert them into electrical signals.

This is placed in the activated sludge mixture (subject) in the aeration tank.

Light from a lamp 3 provided inside the light source section 1 is projected onto the subject through the light projection window 4, and the light projected onto the subject is transmitted and scattered according to the concentration of activated sludge, and is transmitted through each light receiving window of the light receiving section 2. 6 and reaches each light receiving element 5, where it is converted into an electrical signal.

In this case, since the distances of the two light receiving sections 2 from the light source section 1 are different, the amount of transmission attenuation of light for the same density is different, and the respective amounts of received light are different.

Utilizing the fact that the ratio of the amount of received light is proportional to the concentration of activated sludge, measurements are performed based on the ratio of electrical signals converted by the light receiving section 2. If the light projecting window 4 is dirty or if both the light receiving windows 6 of the light receiving section 2 are dirty to the same degree, there is an advantage that the influence on the measured value can be reduced to some extent.

However, the activated sludge suspended matter contains adherent algae that perform photosynthesis, and it adheres only to the light projection window 4 of the light source unit 1 that projects light into the activated sludge, and within about a week. It grows to such an extent that it covers the light projection window 4 and blocks the light source.

These algae are often green algae.

Therefore, if this is left untreated, measurement will become impossible or sensitivity will drop significantly.

As a result of various experiments to solve the above-mentioned problems, the inventors found that if only light in the wavelength range in which these algae do not grow was used as a light source, the growth of algae could be suppressed and the light on the floodlight window could be reduced. They discovered that the adhesion of algae was almost eliminated, and by installing a filter in the light projection window of the light source that allows only light in this wavelength range to pass, they were able to obtain good results.

The light projection window 4 of the light source section 1 is usually made of Teflon (tetrafluoroethylene).
A green filter 7 (passage wavelength range of 520 to 570 nanometers) is attached inside the film.

When using a detector with this structure, the results of continuous measurement for about one month showed that almost no algae adhesion was observed.
Measured values were also normal.

Green algae are thought to receive white light, transmit and reflect only the light in the green wavelength range, and use light in other wavelength components for growth.

Therefore, if only light in the green wavelength range is used as a light source, there will be no light component that can be used for growth, so photosynthesis will not occur, and the growth of algae will be suppressed.

This invention eliminates the drawback of the conventional method of frequently requiring cleaning of the detection unit and interrupting measurement each time, and enables stable and accurate continuous measurement over a long period of time. The effect is remarkable.

In addition to green algae, activated sludge may also contain a small amount of brown algae, but as mentioned above, their growth and adhesion can be prevented by using an appropriate filter with a wavelength range to pass through.

Therefore, the filter used in the light source section is not limited to the above-mentioned green wavelength range.

[Brief explanation of drawings]

The figure is a sectional view showing an example of the structure of the detector of the aeration tank baijiu sludge concentration measuring device according to the present invention. 1... Light source part, 2... Light receiving part, 3...
... Lamp, 4 ... Floodlight window, 5 ...
- Light receiving element, 6... Light receiving window, 7... Filter.

Claims (2)

[Scope of utility model registration request] (1) A light source section provided to project light onto the test object, which is composed of a lamp or the like, and the light transmitted from the light source section through the test object;
In the detector of the aeration tank internal sludge concentration measuring device, which is composed of a light receiving section installed to receive scattered light and convert it into an electrical signal, the activity of the subject is detected in the light projection window of the light source section. A detector for measuring sludge concentration inside an aeration tank, which is equipped with a filter that passes only light in a wavelength range in which algae generated in sludge do not grow. (2) Utility model registration claim (1) in which a filter that passes wavelengths of 520 to 570 nanometers, where green algae do not grow, is attached to the light source window; Measuring device detector.