JPH064886Y2 - Settling tank - Google Patents

Description

[Detailed Description of the Invention] [Industrial field of application] The present invention relates to an improvement of a sedimentation treatment tank for treating sewage, in particular, a sedimentation treatment tank arranged on a floating body.

[Prior Art] FIG. 2 shows a general flow of sewage treatment.

A is a first settling tank for removing large solids in sewage. In the aeration tank B, a BOD component contained in the sewage is treated with microorganisms, so air is blown in for aeration. C is a final settling tank, and the settling tank which is the subject of the present invention is adopted, and sludge contained in the aerated activated sludge mixed solution is allowed to stand and settle. D is a sterilization tank in which the supernatant of the final precipitation tank is sterilized and discharged.

The sludge obtained from the first settling tank A and the final settling tank C is reused as fertilizer, incinerated in an incinerator, or disposed of in landfill.

FIG. 3 shows an outline of the precipitation treatment tank used in the final precipitation tank C.

A settling tank 1 is divided into an inflow chamber 2 and a settling chamber 3 by a straightening vane 4 having many holes. An inflow pipe 5 is attached to the inflow chamber 2, and is usually 2000 to 300.
The activated sludge mixed solution of 0PPm is supplied, and a uniform flow is formed by the straightening vanes 4 and flows into the precipitation chamber 3. An overflow weir (a perforated pipe may be used) 6 for discharging treated water is placed in the settling chamber 3, and the supernatant of the wastewater left standing for about 3 hours has a suspended matter concentration of about 10 PPm or less. And is discharged from the drainage pipe 7.

The sludge settled on the bottom of the settling chamber 3 is scraped to the inflow chamber 2 side by a scraper (not shown) or the like, and the straightening plate 4
It is collected in the sludge chamber 8 formed at the bottom of the inflow chamber 2 through the gap between the sludge chamber 3 and the sedimentation chamber 3. The collected sludge of about several thousand to tens of thousands of PPm is taken out through the discharge pipe 9.

[Problems to be solved by the invention]

Conventional sewage treatment equipment is located on the ground, and if you try to install the equipment on a floating body, various problems will occur. In other words, what is originally used in a stationary state,
There are various effects when used in a rocking place called a floating body.

Initially, the settling tank A precipitates large solids in the sewage and is not very sensitive to rocking of the tank. Further, the aeration tank B needs to be actively stirred, and swinging of the tank is rather preferable.

However, in the final settling tank C, this swing becomes a big problem. That is, it is desirable that the sedimentation in the sedimentation chamber 3 of the final sedimentation tank C is activated sludge having a specific gravity almost equal to that of water, so that the sedimentation should be performed as gently as possible.

However, if the sewage treatment equipment is installed on the floating body, the floating body will not be shaken to a large extent due to the influence of the tide, waves and wind. Even if the floating body, that is, the settling tank 1 is tilted only a few degrees, the liquid level in the tank is tilted, and the activated sludge mixed liquid passes between the inflow chamber 2 and the settling chamber 3 through the straightening plate 4 each time. You will come and go.

It is the inlet part from the inflow chamber 2 into the settling chamber 3, that is, the vicinity of the straightening plate 4, that has the greatest effect on the sludge settling.
Flocking occurs due to the pseudo-collection of sludge at this inlet portion, and the activated sludge mixed liquid containing the pseudo-collected flocs flows into the settling chamber 3 and the settling separation proceeds.

Therefore, the sedimentation is inhibited by the activated sludge mixed liquid flowing back and forth through the flow regulating plate 4, and the sludge finally collected is also stirred, so that the effect of sufficient sedimentation separation cannot be obtained.

[Means for solving problems]

The present invention comprises a settling tank having an inflow chamber and a settling chamber, means for supplying an activated sludge mixture (raw water) to the inflow chamber,
In the settling tank having means for draining the supernatant from the settling chamber, means for scraping sludge settling in the settling chamber of the settling tank, and means for discharging the sludge slid up, Below the standard water level of the sedimentation chamber,
In addition, a ceiling plate that keeps the water in a full state is arranged, and the bottom of the inflow chamber formed by the current plate is raised above the bottom of the settling chamber.

[Action]

By providing the ceiling plate in the inflow chamber, the nearly enclosed space of the inflow chamber surrounded by the current plate and the ceiling plate is filled with water, and the liquid surface does not tilt. Therefore, even if the entire settling tank is tilted and the liquid level in the settling chamber is tilted, the activated sludge mixture does not come in and out through the straightening vane.

Moreover, since the bottom of the inflow chamber formed by the straightening plate is raised above the bottom of the settling chamber, the sludge accumulated in the settling chamber is not stirred.

〔Example〕

Hereinafter, the present invention will be described with reference to a sedimentation treatment apparatus of one embodiment shown in FIG. 1. However, the structural actions of those denoted by reference numerals 1 to 9 are the same as those in FIG.

In the figure, 10 is a ceiling plate, which is attached so as to cover the entire surface of the inflow chamber 2, and its position is below the reference water level L in the settling chamber 3. Although not shown,
Attach an air vent pipe equipped with a check valve etc. to the ceiling board 10,
Even when the amount of the activated sludge mixed liquid flowing into the inflow chamber 3 changes, the inflow chamber is always filled with water.

Although the bottom of the inflow chamber 2 is formed by the straightening vane 4, the height of sludge settled at the bottom of the settling tank 3 is hidden by the swing of the swinging floating body or moves back and forth from side to side. Is also formed at a high position sufficiently separated from the bottom of the settling chamber 3 so that the flow straightening plate 4 does not shear or stir.

When such a settling tank is placed on the floating body, the water surface in the settling chamber 3 is inclined according to the shaking of the floating body. However, since the ceiling plate 10 is attached to the inflow chamber 2 and only the upper air is discharged to the outside by the air vent pipe attached to the ceiling plate 10, it is always full of water, and the activated sludge mixed liquid is There is no going back and forth between the inflow chamber 2 and the sedimentation chamber 3.

Moreover, the rocking of the settled sludge at the bottom of the settling chamber 3 caused by the rocking of the floating body cannot be avoided by the above means, but the straightening plate of the inflow chamber 2 formed by the straightening plate 4 contacts the settling sludge layer. Since it is formed when the sludge is sufficiently high, there is no need to shear or agitate the rocking sedimentation sludge, and the floating of extra particles from the sedimentation sludge is suppressed.

Due to the above-mentioned overall effect, the sludge can be settled smoothly in the settling chamber 3, and it is possible to improve the settling separation efficiency that is no different from the above-ground equipment.

In addition, in the above-described embodiment, an example in which the bottom portion of the inflow chamber 2 is formed by the horizontal straightening vane 4 is shown, but a local volume of sludge is not generated on the straightening vane 4 and a straightening effect is added. Then, it is possible to make the shape suitable for the situation, including the inclined type or the V type.

[Effect of device]

By using the settling tank of the present invention, it becomes possible to install sewage treatment equipment on a floating body, which has been considered difficult in the past.
It is extremely useful in industry.

[Brief description of drawings]

FIG. 1 is a diagram of a precipitation treatment tank showing an embodiment of the present invention, and FIG.
The figure shows the flow of sewage treatment, and Fig. 3 shows the conventional settling tank. 1: sedimentation tank, 2: inflow chamber, 3: sedimentation chamber, 4: rectification chamber, 5: inflow pipe, 6: weir, 7: drainage pipe, 8: sludge chamber, 9: discharge pipe, 10: ceiling plate

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Kunihiro Ikegami 1-1 1-1 Atsunoura-machi, Nagasaki-shi, Nagasaki Mitsubishi Heavy Industries, Ltd. Nagasaki Research Institute (72) Yoshiteru Imaizumi 1-1-1 Atsunoura-cho, Nagasaki-shi, Nagasaki Mitsubishi Heavy Industries, Ltd. Nagasaki Research Institute (72) Inventor Tamotsu Tsukabe 1-1, Atsunoura-machi, Nagasaki, Nagasaki Prefecture Mitsubishi Heavy Industries Ltd. Nagasaki Shipyard (72) Kazuo Masuda 1-1, Atsunoura-cho, Nagasaki, Nagasaki Prefecture Mitsubishi Heavy Industries Ltd. Nagasaki Shipyard (72) Inventor Akio Enomoto 1-1, Atsunoura-cho, Nagasaki-shi, Nagasaki Mitsubishi Heavy Industries Ltd. Nagasaki Shipyard

Claims (1)

[Scope of utility model registration request] 1. A settling tank having an inflow chamber and a settling chamber,
Means for supplying the activated sludge mixture to the inflow chamber, means for draining the supernatant from the settling chamber, means for scraping the sludge settled in the settling chamber of the settling tank, and means for discharging the scraped sludge And a ceiling plate for keeping the water level of the inflow chamber below the reference water level of the settling chamber and filled with water, and the bottom part of the inflow chamber formed by a straightening vane A settling tank characterized by being raised from the bottom of the chamber.