JPH0771674B2 - Clear water discharge device for batch type waste water treatment equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Application The present invention is a batch treatment tank that uses activated sludge for sequentially performing aeration, sedimentation, and supernatant water drainage processes in one batch treatment tank. The present invention relates to a clear water discharge device in a waste water treatment device.

B. Outline of the Invention The present invention is a batch treatment tank containing activated sludge, an aeration device, a supernatant water drainage device for discharging the supernatant water of the treated wastewater to the outside, and a reservoir in the batch treatment tank. In the supernatant water discharge device in a batch type treatment device provided with a level switch for detecting the upper limit level and the lower limit level of the drainage level and operating and stopping the aeration device and the supernatant water discharge device, the batch treatment The drainage pipe is fixed in the tank so that the vertical position can be adjusted, and the suction part at the lower end of the drainage pipe is arranged at the lower part of the lower limit level above the interface of the settling activated sludge tank, and the suction part is By installing a suction port that is oriented horizontally, it is possible to eliminate the moving parts that follow changes in the water level of the supernatant water, avoid damage due to exercise, and improve durability and reliability. Suction of settled sludge Can be avoided, also is obtained as a vertical position adjustment and maintenance of the drainage pipe can be easily performed.

C. Conventional technology Focusing on small-scale sewage treatment facilities, the batch activated sludge method is drawing attention. In this method, activated sludge is used in one batch treatment tank, and each process of aeration, precipitation, and supernatant water drainage is sequentially performed to perform drainage treatment.

Figures 3 and 4 show the conventional batch-type wastewater treatment equipment of this type. FIG. 3 is a schematic explanatory view of a batch type waste water treatment device, and FIG. 4 is a schematic explanatory view of a supernatant water discharge device attached to the batch type waste water treatment device. In the batch type waste water treatment equipment of FIG. 3, an aeration device 3 is provided at the bottom of the batch treatment tank 1 containing the activated sludge 2 so that the outside air is sent from the blower 4 outside the tank to the aeration device 3 and the treatment is performed. The supernatant water discharge device 5 is provided on the side of the tank 1. The level switch 6 provided in the treatment tank 1 is for detecting the upper limit level and the lower limit level of the water level in the treatment tank 1 and controlling the operation and stop of the aeration device 3 and the supernatant water discharge device 5. As shown in FIG. 4, the supernatant water discharge device 5 is attached to the inside of the tank wall 7, and has a water distribution pipe such as a flexible hose 8 for discharging the supernatant water to the outside via the pump P. A float 9 for always holding the tip of the hose R above the supernatant water, and a cover 10 for directing the suction port below the scum layer so as not to suck the scum floating above the surface of the supernatant water into the hose 8. Is equipped with.

Then, in this batch type waste water treatment equipment, the raw water W
Is fed to the batch treatment tank 1, and the water level is the upper limit level HWL.
When it reaches, the level switch 6 detects this and starts the blower 4 to execute the aeration process. When the treatment of the raw water W is completed, the blower 4 is stopped and the aeration process is completed. Subsequently, solid-liquid separation is performed in the precipitation step, and the separated supernatant water is sucked by the supernatant water discharge device 5 and discharged to the outside. When the water level of the clear water reaches the lower limit level BWL, level 6 detects this and stops the operation of the pump P. What is important at this time is that scum generated due to the denitrification phenomenon in the precipitation step is not discharged to the outside by the discharge device 5 together with the supernatant water. Therefore, the supernatant water discharger 5 is provided with the cover 6
As a result, clear water is inhaled from the lower part of the scum layer. The hose 8 having elasticity or flexibility can be moved up and down by the float 9 so as to follow the water level of the clear water.

D. Problems to be Solved by the Invention In the above-described conventional clear water discharge device 5, since the hose 8 moves up and down following the water level of the clear water, the hose 8 is easily damaged by repeated expansion and contraction or bending, and therefore, due to perforation. May cause deterioration of discharged water quality. Also, float 9
May come into contact with the tank wall 7 to hinder the follow-up operation to the water level of the supernatant water, which may also lead to deterioration of discharged water quality. The present invention is intended to solve the above problems of the conventional clear water discharge device 5.

E. Means for Solving the Problems In the present invention, in order to solve the above-mentioned conventional problems, a drain pipe is fixed in the batch treatment tank so that the vertical position of the drain pipe can be adjusted, and the suction portion at the lower end of the drain pipe is fixed. The supernatant water discharge device in the batch type waste water treatment device was configured by being arranged at a lower part of the lower limit level above the interface of the settling activated sludge tank, and by providing a suction port oriented horizontally in the suction part.

F. Operation In the supernatant water discharging device of the present invention, as in the conventional case, when the precipitation step of the batch treatment is completed, the pump is operated to start discharging the supernatant water from the drain pipe. When the water level of the clear water gradually falls and reaches the lower limit level, the level switch detects this and stops the operation of the pump, and the drainage process is completed. Since the suction part at the lower end of the drainage pipe is located below the lower limit level of the supernatant water and above the interface of the settling activated sludge tank, the suction port remains above the sludge interface when the drainage of the supernatant water is completed. Since it is located at an appropriate position below the surface of the supernatant liquid, and thus the inhalation of the settled sludge is avoided and the inlet is oriented horizontally, the intake of scum or sedimented sludge is possible even when the remaining supernatant layer is set small. Avoided. The sludge interface shall be maintained at a constant level by periodical blow-out of settling sludge as in the past.

G. Embodiment An embodiment of the present invention is shown in FIGS. 1 and 2. FIG. 1 is a schematic explanatory view of a batch type waste water treatment device, and FIG. 2 is a perspective view of a part of the supernatant water discharge device. In the figure, the same components as those shown in FIG. 3 are designated by the same reference numerals and the description thereof will be omitted.

In FIG. 1, a guide pipe 21 is vertically fixed in the treatment layer 1, and a drain pipe 22 is supported by the guide pipe 21 and vertically fixed in the treatment tank 1. That is,
The drainage pipe 22 is fixed to the guide pipe 21 via the level adjustment fixing portion 23 so that the vertical position of the drainage pipe 22 can be adjusted, and the middle portion is supported by the plurality of steady rests 24 on the guide pipe 21 at a predetermined interval. There is. Then, the water distribution pipe 22 can be adjusted in its vertical position by loosening the level adjustment fixing portion 23. Also drain pipe
22 is capable of sucking the clear water in the treatment tank 1 and discharging it to the outside by the pump P as in the conventional case, but it is not necessary to have flexibility. The suction part 25 at the lower end of the drainage pipe 22 is arranged below the lower limit level BWL of the water level and above the interface M of the sedimented activated sludge layer, and the suction part 25 is horizontal as shown in FIG. The extending portion 26 is provided. And the horizontal extension 26
Has a suction port 27 that is oriented in the horizontal direction at its tip. Various shapes of the suction portion 25 can be considered as illustrated in FIGS. 2 (a), (b) and (c). That is, FIG. 2 (a) shows a tubular body bent in an L-shape, and FIG. 2 (b) shows a tubular body branched into a T-shape. In the structure shown in (b), upper and lower discs 28 and 29 are attached to the tip of the tubular body with a spacer 30 at a distance from each other, and a suction port 27 is formed between the discs 28 and 29 over the entire circumference. It is a thing.

In this embodiment, as in the conventional case, after the precipitation step of the batch treatment is completed, the pump P is operated to suck the supernatant water from the suction port 27 at the lower end of the drain pipe 22 and discharge it to the outside of the tank. Enter the process of doing. When the level of the supernatant water gradually decreases as the drainage progresses and reaches the lower limit level BWL, the level switch 6 detects this and stops the operation of the pump P, and the drainage process is completed. Suction part 25 at the lower end of the drain pipe 22
Is located below the lower limit level BWL of the supernatant water and above the interface M of the sedimented activated sludge layer.
27 is at an appropriate position below the supernatant water surface that remains on the sludge interface M when the drainage of the supernatant water is completed. Therefore, suction of sedimented sludge is avoided, and the suction port 27 is oriented in the horizontal direction. Inhalation of scum or settled sludge is avoided even when the supernatant water layer is set to a small amount. It is assumed that the sludge interface M is maintained at a constant level by periodical withdrawal of the settled sludge as in the conventional case.

H. Effects of the Invention As described above, in the present invention, the drain pipe is fixed in the batch treatment tank so that the vertical position can be adjusted, and the suction part at the lower end of the drain pipe is below the lower limit level and is settled. It is arranged at the upper position of the interface of the activated sludge tank, and the suction part is provided with a horizontally oriented suction port to configure the supernatant water discharge device in the batch type waste water treatment device, so that it follows changes in the supernatant water level. Since there is no moving part for this, it is possible to avoid damage to the water pipe due to the follow-up motion and improve durability and reliability, and the suction part is located below the lower limit level and at the interface of the sedimented activated sludge layer. By arranging in the upper position, it is possible to avoid inhalation of scum and sedimented sludge, and it is possible to easily adjust the vertical position of the drainage pipe and easily perform maintenance and inspection.

[Brief description of drawings]

1 and 2 show an embodiment of the present invention.
FIG. 1 is a schematic explanatory view of a batch type waste water treatment device, FIG. 2 is a perspective view of a part of a supernatant water discharging device, FIG. 3 is a schematic explanatory view of a conventional batch type waste water treatment device, and FIG. FIG. 3 is an explanatory view of a supernatant water discharge device attached to the batch type waste water treatment device. 1 ... Batch treatment tank, 2 ... Activated sludge, 3 ... Aeration device,
6 ... Level switch, 22 ... Drain pipe, 26 ... Suction part,
27 ... Inlet, M ... Interface, P ... Pump, BWL ... Lower level, HWL ... Upper level, W ... Drain.

Claims (1)

[Claims] 1. A batch treatment tank containing activated sludge, an aeration device, a supernatant water discharge device for discharging the supernatant water of the treated waste water to the outside, and a water level of the waste water stored in the batch treatment tank. In the supernatant water discharge device in the batch type waste water treatment device provided with a level switch for detecting the upper limit level and the lower limit level and operating and stopping the aeration device and the supernatant water discharge device, in the batch treatment tank In addition, the drainage pipe is fixed so that the vertical position can be adjusted, the suction part at the lower end of this drainage pipe is arranged at the lower part of the lower limit level above the interface of the settling activated sludge tank, and the suction part has a horizontal direction. Clear water discharge device for batch type waste water treatment equipment, which is equipped with a suction port facing toward.