JPH049599B2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a sewage treatment device that performs activated sludge treatment of sewage by repeating a cycle of aeration, sedimentation, and discharge within a single treatment tank, and in particular, it scrapes scum floating on the water surface in the treatment tank. The present invention relates to a sewage treatment device that allows only the supernatant liquid to be discharged.

[Conventional technology]

Generally, in batch-type activated sludge treatment equipment that performs activated sludge treatment of sewage in a single treatment tank, the supernatant liquid is discharged after the sedimentation process, but at the time of discharge, scum is suspended in the treatment tank. There may be cases where In this case, it is necessary to prevent scum from being mixed into the supernatant liquid to be discharged. Therefore, as a measure to prevent scum from being mixed into the supernatant liquid, the discharge pipe for the supernatant liquid is surrounded by a scum bathful (float) to prevent scum from being mixed into the supernatant liquid.

[Problem to be solved by the invention]

In such conventional batch-type activated sludge treatment equipment, when the scum baffle moves downward above the water surface, the scum between the discharge pipe and the scum baffle flows into the discharge pipe, and the supernatant liquid is discharged with scum mixed in. I had the problem of being exposed. This invention was made in order to solve the above problem, and when the supernatant liquid is discharged, the scum floating in the water area near the supernatant liquid discharge means is pushed away in the direction away from the supernatant liquid discharge means. Then,
It is an object of the present invention to provide a sewage treatment device capable of efficiently discharging only supernatant liquid without scum contamination from the supernatant liquid discharge means.

[Means to solve the problem]

The sewage treatment apparatus according to the present invention includes a supernatant liquid discharge means for discharging the supernatant liquid in the discharge process into a treatment tank that repeats an aeration process, a precipitation process, and a discharge process;
It is movable in the direction toward or away from the supernatant liquid discharge means, and after the aeration process and before the discharge process, it moves in the direction away from the supernatant liquid discharge means while immersed and floating on the water surface in the treatment tank. The device is equipped with a scum scraping means that moves and scrapes up scum on the water surface in the direction of separation.

[Effect]

In the sewage treatment apparatus according to the present invention, when discharging supernatant liquid, the scum scraping means is moved in a direction away from the vicinity of the supernatant liquid discharging means, thereby removing the scum floating in the water area near the supernatant liquid discharging means. can be pushed away to a water area far away from the supernatant liquid discharge means, thereby allowing only the supernatant liquid without scum to be discharged from the supernatant liquid discharge means. Moreover, since the scum scraping means when discharging the supernatant liquid is immersed and floating on the water surface, even if the water level in the treatment tank fluctuates drastically, the scum scraping means will follow this water level fluctuation and prevent immersion at the water surface. Since the floating state is reliably maintained, the scum can be reliably pushed away by the scum scraping means.

【Example】

An embodiment of the present invention will be described below with reference to the drawings. In Figures 1 and 2, 1 is a single treatment tank that performs activated sludge treatment of wastewater by repeating a cycle consisting of aeration, sedimentation, and discharge. An air diffuser 2 is arranged to blow air into the wastewater. This aeration device 2 is normally switched and controlled by an aeration blower (not shown), but at this time, it is recommended to use a device that is not easily clogged, such as a jet type aeration device that blows out a gas-liquid mixture. is preferred. Further, in the processing tank 1, a discharge pipe 3 serving as a supernatant liquid discharge means is provided so as to be able to swing up and down. This discharge pipe 3 is for discharging the supernatant liquid during the discharge process following the precipitation process, and is connected to a discharge pipe 5 which is rotatably connected to the shaft pipe 4, and is attached to the free end of this discharge pipe 5. , and an overflow pipe 6 having an open overflow port 6a. Therefore,
When the overflow pipe 6 descends below the water surface, the treatment tank 1
The supernatant liquid inside flows into the overflow pipe 6 from the overflow port 6a, and is discharged to the outside through the shaft pipe 4. Also,
When the overflow pipe 6 is rotated by a rotating means (not shown) so as to be at a position higher than the liquid level, the liquid in the processing tank 1 is not discharged. This invention is particularly characterized in that a scum scraping means 7 is disposed within the processing tank 1 so as to be movable in the direction toward and away from the discharge pipe 3 (in the direction of arrow A in FIG. 2). As shown in FIGS. 1 and 2, the scum scraping means 7 includes a scum scraping float 8 that can reciprocate in the direction of the arrow A while lying on the water surface of the processing tank 1, and The illustrated example configuration has a scum scraping plate 9 attached to the float 8 and submerged at an appropriate depth when the float 8 floats on the water surface, and a support plate 10 that supports both ends of the float 8 so as to be movable up and down. It's summery. Next, the operation will be explained. Inside the treatment tank 1, there is an aeration process by operating the aeration device 2, and a precipitation process in which the operation of the aeration device 2 is interrupted and the liquid in the treatment tank 1 is made to stand still to precipitate the sludge in the liquid. The discharge step of lowering the discharge pipe 3 to the water surface and discharging the supernatant liquid is one cycle, and the cycle is repeated to perform activated sludge treatment of the inflowing sewage supplied continuously or at any arbitrary time. Note that the settled sludge in the treatment tank 1 is extracted at an appropriate time. In such an activated sludge treatment cycle, after the aeration process is completed and before the discharge process, the float 8 of the scum scraping means 7 is floated on the water surface near the overflow pipe 6, and the float 8 in this state is floated on the water surface near the overflow pipe 6. Move it horizontally away from the tube 6. Then, if scum is floating in the water area near the overflow pipe 6, the scum is pushed away from the overflow pipe 6 by the float 8 and the scum scraping plate 9 hanging from the float 8. It can be removed. This prevents scum from flowing into the overflow pipe 6.
Only supernatant liquid without scum contamination is smoothly discharged from the discharge pipe 3 equipped with this. In addition, the above float 8
Since both ends of the float 8 are supported by supporting members 10 so as to be able to rise and fall freely, even if the water level in the treatment tank 1 fluctuates rapidly, the float 8 easily follows the water level fluctuation. Even if the water level fluctuates rapidly, the above-mentioned scum removal effect can be smoothly achieved. FIG. 3 and FIG. 4 show another embodiment of the present invention, and a scum scraping means 7 according to this embodiment is shown.
The float 11 is rotatably supported by the discharge pipe 3 and has a float 11 for collecting scum that lands on the water area to the left in the vertical direction of the discharge pipe 3 (see FIG. 4A). This float 11 is provided with a scum scraping plate 13 that is integrally connected to the float 11 and hangs down. Further, the discharge pipe 3 is provided with a scum wraparound prevention plate 13 that hangs down from the overflow pipe 6. According to the above configuration, when moving to the discharge step after the precipitation step, first, the discharge pipe 3 starts descending as shown in FIG. 4. At this time, since the float 11 is rotatably supported by the discharge pipe 3, the fourth
As shown in the figure, it moves to the left (in the direction away from the discharge pipe 3) on the water surface due to buoyancy. Therefore, the scum floating in the water area near the discharge pipe 3 is removed by the float 11 and the scum scraping plate 1.
3, the discharge pipe 3 is pushed away in the direction away from the discharge pipe 3, as in the previous embodiment.
Reliably prevent scum from entering. Note that the scum wrap-around prevention plate 13 hanging from the discharge pipe 3 also prevents scum from flowing in from the back of the discharge pipe 3. 5 and 6 show still another embodiment of the present invention, and the scum scraping means 7 according to this embodiment includes a pair of float support arms 14 fixed on both sides of the discharge pipe 3, and a scum scraping means 7 according to this embodiment. Float support arm 14
A float 15 whose both end shaft portions are movably engaged with an arcuate long hole 14a (see FIG. 6B) provided in the long hole 14a, and a pair of floats that open and close the float 15 along the long hole 14a. Float drive arm 16
It has As shown in FIG. 6, this float drive arm 16 has a structure in which one end is fixed to the float and the other end is slidably engaged with a long hole 17a of a base frame 17 fixed to the processing tank 1. It's summery. Therefore, for example, if the end of the float drive arm 16 is moved along the elongated hole 17a of the base frame 17 by the rotation of the screw or the motor 18, the float 15 is closed as shown in FIG. As shown in FIG.
The discharge pipe 3 supported by the buoyant force moves up and down. Therefore, during the aeration process and the precipitation process, the float 15 is displaced and maintained near the discharge pipe 3, and the discharge pipe 3 (overflow port 6a of the overflow pipe 6) is connected to the water surface, as shown in FIG. 6A. Hold it above. Next, after the precipitation process is completed, the float support arm 16 is attached to the long hole 17 of the base frame 17 using a screw or a motor 18.
When descending along the line a, the discharge pipe 3 moves below the water surface and overflows and discharges the supernatant liquid. At this time, as shown in FIG. 6B, since the float moves in the opening direction, the scum in the water area near the discharge pipe 3 is pushed away in the direction away from the discharge pipe 3, as in the previous embodiments. This reliably prevents scum from entering the discharge pipe 3, and also allows the discharge process to start and end at the same time. The scum scraping means 7 described in each of the above embodiments is not limited to the illustrated example configuration, but may be any device that can push away floating scum in the water area near the discharge pipe 3 in a direction away from the discharge pipe 3. , may have any configuration.

【Effect of the invention】

As described above, according to the present invention, the aeration step,
A supernatant liquid discharging means for discharging the supernatant liquid in the above-mentioned discharging process, and a supernatant liquid discharging means that is movable toward or away from the supernatant liquid discharging means, and a supernatant liquid discharging means for discharging the supernatant liquid in the above-mentioned discharging process into a treatment tank in which the precipitation process and the discharging process are repeated, and a Before the above-mentioned discharge process, a scum scraping means is provided that moves in a direction away from the supernatant liquid discharge means and scrapes up scum on the water surface in the direction of separation, and when the supernatant liquid is discharged, the supernatant liquid Since the scum scraping means is configured to move in a direction away from the water area near the discharge means,
The scum floating in the water area near the supernatant liquid discharge means can be pushed away in the direction away from the supernatant liquid discharge means, thereby allowing only the supernatant liquid without scum to be mixed in from the supernatant liquid discharge means. This has the effect of allowing the water to be discharged smoothly. Furthermore, since the scum scraping means when discharging the supernatant liquid is immersed and floating on the water surface, even if the water level in the treatment tank fluctuates drastically, the scum scraping means always smoothly follows the water level fluctuations and the water surface Since the immersed floating state is reliably maintained, the scum scraping means can reliably push away the scum as described above.

[Brief explanation of drawings]

FIG. 1 is a plan view of a sewage treatment apparatus according to an embodiment of the present invention, FIG. 2 is a schematic vertical sectional view of FIG. 1, and FIG. 3 is a front view of a discharge pipe according to another embodiment of the invention. , FIG. 4 is a configuration explanatory diagram that also serves as an explanation of the operation of a sewage treatment apparatus according to another embodiment of the present invention, FIG. The figure shows an enlarged view of the main part of FIG. 5, FIG. 6A shows the scum scraping float in a closed state, and FIG. 6B shows the scum scraping float in an open state. 1... Processing tank, 3... Discharge pipe (supernatant liquid discharge means), 7... Scum scraping means.

Claims (1)

[Claims] 1. A treatment tank that repeats an aeration process, a precipitation process, and a discharge process; a supernatant liquid discharge means that is installed in this treatment tank and discharges the supernatant liquid in the discharge process; is arranged so as to be movable in the direction toward or away from the supernatant liquid discharge means, and after the aeration process and before the discharge process, moves in the direction away from the supernatant liquid discharge means and discharges the water surface in the direction of separation. A sewage treatment device comprising: scum scraping means for scraping up scum.