JPS618198A - Sewage treatment apparatus - Google Patents

Abstract

PURPOSE:To effectively and certainly exclude the scum of a batchwise activated sludge treatment tank receiving the variation in a water level, by forming a revolving stream by a jet aerator after the completion of a discharge process and discharging scum by a skimmer. CONSTITUTION:When a discharge process is finished, the surface of a liquid is L.W.L and new sewage is flowed in from an inflow port 1a. At the same time, only the recirculation pump of a jet aerator 4 is operated and scum is revolved and fed by a weak flow speed to be collected in the vicinity of the scum discharge port 3a of a skimmer 3. When a liquid level is raised by successively flowed-in sewage to reach H.W.L, a scum discharge valve 9 is opened and scum is discharged out of a tank 1 along with flowed-in sewage. By this method, scum is surely excluded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a batch-type sewage treatment device that can effectively discharge and remove scum.

[Prior art]

Conventionally, in batch-type activated sludge treatment equipment that performs aeration, precipitation, and discharge of supernatant liquid in one tank, the precipitated supernatant liquid is discharged after the sedimentation process, but at this time, scum remains in the treatment tank. are often floating.

The supernatant liquid is discharged by a discharge pipe that moves up and down on the liquid surface, but at this time, this discharge pipe is usually surrounded by a scum baffle to prevent scum from getting mixed in.

However, with conventional systems, when the scum baffle descends above the water surface, the scum inside the scum baffle inevitably flows into the discharge pipe and is discharged, and the scum cannot be separated or removed. . Additionally, it was difficult to create an independent scum discharge mechanism because the water level in the tank changed.

[Summary of the invention]

This invention was made in order to eliminate the above-mentioned drawbacks, and by forming a swirling flow using a jet aerator at the end of the discharge process and discharging scum through a skimmer, scum can be effectively removed from waste water. The purpose is to provide processing equipment.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the drawings.

As shown in FIGS. 1 and 2, the batch activated sludge treatment tank 1 is equipped with a supernatant liquid discharge means 2, a skimmer 3 for discharging scum, and a jet aerator 4 for forming swirl flow and aeration. has been done.

As shown in FIG. 2, the supernatant liquid discharge means 2 discharges the supernatant liquid during the discharge process following the precipitation process,
It consists of a discharge vibro rotatably connected to a shaft pipe 5, an overflow pipe 7 attached to the free end of the discharge vibro with an overflow lower a opened, and a float 8. Therefore, when the overflow pipe T crosses the water surface and descends to W and L, the supernatant liquid in the treatment tank 1 flows through the overflow lower a and into the overflow pipe T, causing the axial vibro to flow. Afterwards, it is discharged outside. In addition, when the overflow pipe 7 is rotated by a rotating means (not shown) so that it is at a position higher than the liquid levels of H, W, and L, the liquid in the processing tank 1 is not discharged.

Here, the skimmer 3 for scum discharge is L, W, L.
It is arranged near M, W, and L at a predetermined distance above the scum discharge port 3m. As shown in FIG. 1, a scum discharge valve 9 is connected which is opened only at a predetermined time after the discharge process is completed.

The jet aerator 4 forms a swirling flow in the direction of the arrow in the treatment tank 1 and performs aeration during the aeration process, and is connected to a circulation pump 10 and an aeration prower 1 that is controlled by switching.
1 is connected. Here, during the aeration process, both the circulation pump 10 and the aeration blower 11 are operated to blow out the gas-liquid mixture. However, during a predetermined period of time after the completion of the discharge process, only the circulation pump 10 is operated to discharge the scum, and only the circulation # in the direction of the arrow is formed.

This predetermined time may be set by a timer or by the water level in the tank.

[For production]

Next, the operation of this invention will be explained.

In the treatment tank 1, there is an aeration process in which a swirling flow is formed in the direction of the arrow by jetting the gas-liquid mixture from the jet aerator 4, and aeration is performed on the inflowing wastewater. a sedimentation step to precipitate activated sludge;
The operation of lowering the supernatant liquid discharge device 2 and discharging the supernatant liquid as one cycle is repeated, and activated sludge treatment is performed on the inflowing sewage supplied from the inlet 11 continuously or optionally. Further, the sludge in the treatment tank 1 is extracted at an appropriate time.

Here, when the discharge process is completed, the liquid level reaches L, W, and L, and new sewage flows in from the inlet 1a.

Almost at the same time, only the circulation pump 10 of the jet aerator 4 is operated, and the scum is conveyed in a circular direction in the direction of the arrow by a weak flow velocity, and is collected near the scum discharge port 3a of the skimmer 3 as shown in FIG. Then, the water level gradually rises due to the inflow of sewage, and the liquid level becomes M.
When W and L are reached, the scum discharge valve 9 controlled by a control device (not shown) changes from the closed state to the open state, and the scum is discharged to the outside of the treatment tank 1 together with the inflowing sewage. Then, after a predetermined period of time (for example, about 3 to 5 minutes) has passed, the scum discharge valve 9
is closed, scum discharge is completed, and a new aeration process is started. Note that the scum discharge valve has a discharge pipe L.
, W, and L, and the discharge pipe may be opened by a signal when the downward movement of the discharge pipe is stopped. If this is done, there is no need to detect M, W, and L. Further, the scum may not be discharged every time, but may be discharged as needed.

〔Effect of the invention〕

As described above, according to the present invention, a swirl flow is formed by the liquid flow generated by the jet aerator after the discharge process is completed, and the scum is discharged through the skimmer, thereby improving the batch type activated sludge treatment tank in which the water level fluctuates. It has extremely excellent effects such as being able to effectively and reliably eliminate scum.

[Brief explanation of the drawing]

FIG. 1 is a plan view of an embodiment of the present invention, and FIG. 2 is a longitudinal sectional view thereof. DESCRIPTION OF SYMBOLS 1... Batch type activated sludge treatment tank, 2... Supernatant liquid discharge means, 3... Skimmer, 4... Jet aerator. Figure Ha ノ; 了'L! :'(7勺1°r: f, r'
;)! -7. t1. ) Figure 2 Procedure amendment (own%)

Claims (1)

[Claims] A batch-type activated sludge treatment tank that repeats the aeration process, precipitation process, and discharge process, and is arranged so that it can move up and down within this treatment tank.
During the above discharge process, L. W. a supernatant liquid discharging means for discharging the supernatant liquid while descending to the L.L. in the processing tank; W. L
a skimmer for discharging scum, which is installed a predetermined distance above and opened for a predetermined period of time after the completion of the discharge process; and a skimmer, which is placed in the treatment tank, and performs aeration by jetting out a gas-liquid mixture during the aeration process. and a jet aerator that moves the scum toward the skimmer by a swirling flow caused by jetting only the liquid over a predetermined period of time after the completion of the discharge process.