JPH01174936A - Method and apparatus for detecting concentration and interface of sludge - Google Patents

Abstract

PURPOSE:To simplify an equipment and to reduce installation cost by performing the detection of the concn. of sludge and the detection of the interface thereof by one detection apparatus, by inserting a transparent body between the light projecting and receiving surfaces of a transmission type optical sensor so as to provide predetermined intervals from both surfaces. CONSTITUTION:A transparent body 3 is inserted between the light projecting and receiving surfaces 2a, 2b of the transmission type optical sensor, which are provided in opposed relationship at a predetermined interval through the sewage in a sewage treatment tank, so as to provide predetermined intervals from said surfaces 2a, 2b. By this structure, the interposing width of sewage is brought to a contracted state and, in this state, the concn. of sludge is detected after the discharge of supernatant water. Further, the insertion of the transparent body is released to increase the separation width of sewage and, in this state, the interface of sludge at the time of sedimentation is detected. By this method, since the detection of the concn. of sludge after the discharge of supernatant water and the detection of the interface of the sludge at the time of sedimentation can be performed by one interface detection apparatus, the equipment is simplified.

Description

TECHNICAL FIELD OF THE INVENTION The present invention relates to a method and apparatus for detecting sludge concentration and interface in a sewage treatment tank.

[Background of the invention]

In various biological wastewater treatment methods that use suspended microorganisms, including the activated sludge method, it is necessary to maintain a certain level of microorganisms in the sewage treatment tank and prevent sludge entrainment when supernatant water is discharged. Therefore, sludge concentration detection and interface detection are extremely important. 49. In order to automate the intermittent aeration method and obtain optimal processing conditions, the above detection work is indispensable and important.

However, when using the original sensor to detect the sludge concentration and interface, there are
The distance between the light receiving surfaces is as small as about 1 cIL, whereas the distance suitable for interface detection is as large as about 2 to 5 cIL. Therefore, two detection devices, one for concentration detection and one for interface detection, are required, which makes the equipment complicated and increases the equipment cost.

[Purpose of the invention]

An object of the present invention is to detect sludge concentration in order to always maintain a certain amount of sludge microorganisms in a sewage treatment tank, and to detect an interface in order to prevent sludge entrainment when discharging top water into a single detection device. ), it contributes to simplifying equipment and reducing equipment costs.

[Structure of the invention]

In the method for detecting the concentration and interface of sludge according to the present invention, a predetermined gap is formed between the light emitting and light receiving surfaces of transmission type optical sensors that are arranged to face each other at a predetermined distance across the sewage in the sewage treatment tank. By inserting a transparent body while maintaining the above, the width of the intervening sewage is reduced, and in this state, the concentration of sludge after discharge of upper U water is detected, and by canceling the insertion of the transparent body. The sewage separation width is increased, and this state is used to detect the interface during sludge settling.

In addition, in the device for detecting the sludge concentration and sedimentation interface according to the present invention, the transmitting and receiving surfaces of the transmission type optical sensor are arranged to face each other at a predetermined interval, and the transmitting and receiving surfaces of the transmission type optical sensor are arranged to face each other at a predetermined interval. A transparent body that can be inserted while maintaining a predetermined gap with the light emitting/receiving surface is installed perpendicular to the optical path of the original sensor, so that when the transparent body is inserted, the width of the intervening sewage is reduced. In addition, when the transparent body escapes, the intervening width of the sewage is expanded, so that the configuration is suitable for detecting the interface when the sludge settles.

〔Example〕

In the drawings of the embodiment, reference numeral 1 denotes a twin-shaped or annular float that rises and falls according to the water level in the sewage treatment tank, and has vertical surfaces 1a and 1b facing each other with a gap G in which water in the tank can be present. A light emitting surface 2a of a transmission type optical sensor is buried in one vertical surface 1a so as to face the gap G, and a light receiving surface 2b concentrically facing the light emitting surface 2a is buried in the other vertical surface 1a. 1
The light emitting/receiving surfaces 2a and 2b constitute the sensing section 2 of the optical sensor. The buoyancy of the float 1 is set so that the sensing part 2 is located at an arbitrary predetermined depth below the surface of the water in the tank.

Reference numeral 3 is a transparent body such as a glass plate, and the string 4 is inserted from the upper part of the processing tank, for example, so that it can be inserted into the gap G while maintaining a predetermined gap g between the light emitting/receiving surfaces 2a and 2b of the original sensor. The sensor is hung vertically, or its root is supported on the bottom of the tank, and is erected perpendicular to the optical path of the original sensor. As shown in Figure 1, when the 70-tooth 1 is lowered, the light emitting/receiving surface 2
Since the transparent body 3 is inserted into the gap G while maintaining a predetermined gap g between a and 2b, the width of the intervening sewage is reduced, making it suitable for detecting the concentration of sludge. Furthermore, as shown in Fig. 2, when the float 1 rises, the transparent body 3 escapes from the gap G, expanding the width of the sewage between the projection and reception surfaces 2a and 2b, making it suitable for interface detection. becomes. 5a is the vertical surface 1a of the gap G.

A wiper 5b is attached to the upper edge of the transparent body 3 so as to be in sliding contact with the transparent body 30, and a wiper 5b is attached to the lower edge of the vertical surface 1a and lb so as to be in sliding contact with both sides of the transparent body 30. , slides in conjunction with the raising and lowering operation of the float 1 each time the sewage treatment tank is discharged or filled with water, and controls the cleaning action of the light emitting/receiving surfaces 2a, 2b and the transparent body 3.

In batch discharge type intermittent aeration control, sludge sedimentation and overflow water are discharged after intermittent aeration ends.

The water level in the sewage treatment tank when the sludge settles depends on the amount of inflow of raw water, forming a high water level t2 as seen in Figure t42, and the float 1 rises accordingly and narrows [G Since the transparent body 3 is released from inside, the light emitting/receiving surface 2a
, 2b is expanded, and a system for detecting the interface is prepared. Therefore, by the interface detection action of the optical sensor, when the layer depth of the supernatant water increases to a predetermined value due to the descent of the interface t, for example, a separate supernatant water discharge device is operated, and the supernatant water discharge device is activated. When the top water layer depth decreases to a predetermined value due to the operation of the clear water discharge device, the operation of the clear water discharge device is temporarily stopped, and the system detects that the interface t has further lowered. If an electrically connected nine discharge control circuit is configured so that the supernatant water discharge device continues to stop operating until the layer depth of the supernatant water increases and recovers to a predetermined value after a certain period of time, the sludge Accidents involving water can be prevented and the quality of treated water can be guaranteed.

After discharging supernatant water, the water level in the sewage treatment tank should be low, and the first
As seen in the figure, a low water level L1 is formed, and the float 1 is lowered accordingly, and the transparent body 3 is inserted into the narrow gap G, so that the throwing light receiving surface 25L.

The intervening width of sewage between 2b is reduced, and a system for concentration detection is prepared. Therefore, if the concentration detection function of the optical sensor determines that the sludge concentration in the sewage treatment tank is higher than a predetermined concentration, a separate sludge transfer mechanism is activated to remove the high concentration sludge in the sewage treatment tank. At the same time, the supernatant water in the sludge concentration adjustment tank is overflowed into the sewage treatment tank to dilute the sludge concentration in the sewage treatment tank, and the sludge concentration in the sewage treatment tank is lowered to a specified concentration. If the concentration of sludge is also determined to be low, a separate sludge reducing machine is operated to return the settled sludge in the sludge concentration adjustment tank to the sewage treatment tank and make the sludge concentration in the sewage treatment tank thicker. If you keep it,
The sludge concentration in the sewage treatment tank can be adjusted so that a constant amount of sludge microorganisms is always retained.

〔Effect of the invention〕

According to the present invention, the detection of the concentration of sludge after discharging supernatant water and the detection of the interface during settling of the sludge are performed by one interface detection device, and there is an advantage that the equipment can be made into a cylinder. Moreover, by combining this with a necessary device, it is possible to always maintain a certain amount of sludge microorganisms in the sewage treatment tank, and it is possible to prevent sludge entrainment after supernatant water is discharged.

[Brief explanation of the drawing]

The drawings are longitudinal sectional side views illustrating an embodiment of the apparatus of the present invention, in which FIG. 1 shows a state in which it is in a sludge concentration detection system, and FIG. 2 shows a state in which it is in an interface detection device. 2a...Projecting surface of fi-1x sensor, 2b...
... Light-receiving surface of the optical sensor, 3 ... Transparent body,
g...Predetermined gap. Patent applicant Tsurumi Seisakusho Co., Ltd.

Claims (1)

[Scope of Claims] [Claim 1] A transparent body is provided with a predetermined gap between the light emitting and light receiving surfaces of the transmission type optical sensor, which are arranged to face each other at a predetermined distance across the sewage in the sewage treatment tank. By inserting the transparent body, the width of the sewage is reduced, and in this state, the concentration of sludge after supernatant water is discharged is detected, and by removing the transparent body, the width of the sewage is increased. A method for detecting the concentration and interface of sludge, characterized in that the interface is detected when the sludge settles based on this state. [Section 2] The transmitting and receiving surfaces (2a) and (2b) of the transmission type optical sensor are arranged so as to face each other at a predetermined interval.
b) Do not allow sewage in the sewage treatment tank to intervene between them;
A transparent body (3) that can be inserted with a predetermined gap (g) between the light emitting/receiving surfaces (2a and 2b) is installed perpendicularly to the optical path of the optical sensor, and when the transparent body (3) is inserted, waste water is removed. The intervening width of the transparent body (3) is reduced to become a mode suitable for detecting the concentration of sludge, and when the transparent body (3) escapes, the intervening width of sewage is expanded to become a mode suitable for interface detection when sludge settles. A device that detects the concentration and interface of sludge.