JPS5815037B2 - Sewage purification equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a sewage purification device for purifying sewage based on an activated sludge method.

When treating wastewater using the activated sludge method, an important issue is how to quickly remove activated sludge from the treated liquid.

Most commonly, activated sludge is removed by transferring the aerated liquid to a settling tank, allowing the activated sludge contained in the liquid to settle, and allowing the supernatant to overflow.

However, since activated sludge requires a long time to settle, the treatment efficiency is low.

In addition, cutting off the separated activated sludge from oxygen supply for a long period of time leads to a decrease in the activity of the activated sludge, and when a part of it is returned to the aeration tank and involved in biochemical oxidation again, the activity is restored. This causes the inconvenience of taking a long time.

An object of the present invention is to provide a sewage purification device that allows activated sludge to rapidly settle and to participate in biochemical oxidation without reducing the activity of the activated sludge.

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

Reference numeral 1 in the figure indicates a processing tank with an open top surface, and an aeration mechanism 2 is provided within this processing tank 1.

The aeration mechanism 2 includes three coaxially arranged cylinder bodies 3, 4,
5, each having a primary aeration chamber 6. A settler 7 and a secondary aeration chamber 8 are formed.

The primary aeration chamber 6 communicates with the inside of the processing tank 1 at its bottom, and also with the settler 1 through a hole 3a provided at the upper end of the cylindrical body 3.

In addition, the secondary aeration chamber 8 has its bottom located at the bottom of the settler 7.
The top portions communicate with the inside of the processing tank 1, respectively.

1 further 1
A diffuser 9.10 is arranged at the bottom of each of the secondary aeration chamber 6 and the secondary aeration chamber 8, respectively.

The diffuser 9 is for blowing air supplied through the pipe 11 into the liquid in the primary aeration chamber 6,
The diffuser 10 is provided to blow high-concentration oxygen gas (here, gas containing oxygen at a higher concentration than air) sent through the pipe 12 into the liquid in the secondary aeration chamber 8. There is.

Furthermore, a separator 14 is provided in the processing tank 1 to form an annular separation chamber 13 between the processing tank 1 and the upper end of the peripheral wall thereof.

This separation chamber 13 is for temporarily storing the liquid in the treatment tank 1 and separating the activated sludge contained in this liquid by sedimentation, and the supernatant liquid overflows the upper edge of the treatment tank 1. Afterwards, it enters receiver 15.

The upper end of the separate lake 14 is connected to the upper end of the cylindrical body 4 to form a closed chamber for collecting high concentration oxygen gas released onto the liquid surface of the secondary aeration chamber 8.

Furthermore, a sludge pipe 16 connecting the separation chamber 13 and the secondary aeration chamber 8 is provided.

One end of the sludge pipe 16 opens at a suitable location within the separation chamber 13, preferably at the upper end of the sludge layer formed within the separation chamber 13.

The inflowing wastewater to be treated is introduced into the bottom of the primary aeration chamber 6 through the pipe 17, and the treated water is taken out from the receiver 15 through the pipe 18.

In addition, the activated sludge separated in the separation chamber 13 is transferred to the sludge pipe 1
6 and is returned to the secondary aeration chamber 8.

The air blown into the liquid existing in the primary aeration chamber 6 from the diffuser 9 becomes bubbles and disperses in this liquid.
It has the functions of expelling CO□ present in the liquid, supplying oxygen to the liquid, and giving upwelling force to the liquid.

As a result, the liquid rises within the primary aeration chamber 6 and transfers to the settler 7 from the hole 3a.

Air bubbles present in the liquid are separated from the liquid while the liquid rises in the primary aeration chamber 6 and then descends in the settler 7, and is discharged to the outside.

The liquid that has reached the bottom of the settler 7 enters the secondary aeration chamber 8 adjacent thereto, and enters the diffuser 1 provided at the bottom.
Receives high concentration oxygen gas injection from 0.

In this case as well, the upwelling force of air bubbles in the liquid causes the liquid to be sucked in from the settler 7 communicating with the bottom of the secondary aeration chamber 80), and at the same time, the activated sludge in the separation chamber 13 is sucked in through the pipe 16. be exposed.

That is, the liquid in the treatment tank 1 is transferred to the primary aeration chamber 6. It circulates through the settler 7 and the secondary tank air tank 8 and returns to the processing tank 1.

Then, inflowing sewage joins this circulating liquid at the bottom of the primary aeration chamber 6, and an amount of liquid corresponding to the flow rate of this inflowing sewage is taken out from the separation chamber 13, and at this time, it settles in the separation chamber 13. Filtered by sludge particles.

Furthermore, the activated sludge that has settled in the separation chamber 13 is returned to the secondary aeration chamber 8 via the sludge pipe 16 without being retained for a long period of time, so its activity does not decrease.

Note that instead of communicating one end of the sludge pipe 16 with the secondary aeration chamber 8, an opening is made at the bottom of the treatment tank 1 like a pipe 19, and the activated sludge is Alternatively, the suction may be performed.

) Also, as shown in FIG. 2, when high concentration oxygen gas is supplied from the pipe 11 to the diffuser 9 in the primary aeration chamber 6, and air is supplied from the pipe 12 to the diffuser 10 in the secondary aeration chamber 8. A similar effect can be expected.

In this case, the upper part of the secondary aeration chamber 8 is opened, and the upper part of the primary aeration chamber 6 and the settler 7 is closed from the outside.

Further, FIG. 3 shows a case where the aeration mechanism 2 is provided outside the processing tank 1.

In this case, a take-out pipe 21 for taking out the liquid inside the treatment tank 1 is provided, and one end of this take-out pipe 21 is connected to the aeration mechanism 2 along with a pipe 17 for introducing the inflowing wastewater. It is connected to the bottom of the cylinder body 3.

Further, the inside of the cylindrical body 5 of the aeration mechanism 2 is connected to the bottom of the processing tank 1 via a return pipe 22.

Furthermore, one end of the sludge pipe 16 is drawn out of the treatment tank 1 and connected to the secondary aeration chamber 8 .

Therefore, the liquid in the treatment tank 1 circulates through the take-off pipe 21, the aeration mechanism 2 and the return pipe 22, during which it is supplied with oxygen and removed with CO2.

The treated liquid is separated from the activated sludge in the separation chamber 13 and then taken out, as in the case shown in FIGS. 1 and 2, and the settled activated sludge is transferred from the sludge pipe 16 to the secondary aeration chamber. Pulled out at 8.

Since the oxygen concentration of the gas separated from the liquid in the cylinder body 5 is quite high at the bottom, it is desirable to extract this gas from the pipe 24 having the blower 23 and supply it to the pipe 12 for reuse. Oxygen usage efficiency improves.

As described above, according to the sewage purification device of the present invention, the sewage to be treated is continuously circulated between the treatment tank and the aeration mechanism, a part of which is transferred to the separation chamber, and activated sludge settles in the separation chamber. After separation, the supernatant liquid is removed from the treated water.

Therefore, compared to the conventional method in which the entire amount of liquid aerated in the aeration tank is sent to the grain tank where it settles and a part of the activated sludge that has been settled and separated in this settling tank is returned to the aeration tank, the treatment efficiency is extremely high. The clarity of the obtained treated water is also good.

In addition, the activated sludge that has been sedimented and separated in the separation chamber does not remain in the separation chamber for a long time and is returned to the aeration mechanism using the liquid flow, so the activity of the activated sludge is always maintained at a high level. , this is also a factor that improves processing efficiency.

[Brief explanation of the drawing]

FIG. 1 is a schematic longitudinal cross-sectional view of a sewage purification apparatus according to one embodiment of the present invention, and FIGS. 2 and 3 are schematic longitudinal cross-sectional views showing apparatuses according to other embodiments, respectively. 1... treatment tank, 2... aeration mechanism, 6.
...Primary aeration chamber, 7...Settler, 8.
...Secondary aeration chamber, 9゜10...Tif user, 13...Separation chamber, 14...Separator, 16...Sludge pipe , 21...
・Takeout pipe, 22...Return pipe.

Claims (1)

[Scope of Claims] 1. A treatment tank containing a liquid to be treated, a cylinder forming a vertical first aeration chamber whose lower end communicates with the treatment tank, and a pipe that guides inflowing wastewater to the bottom of the cylinder. and a diffuser for blowing an oxygen-containing gas into the first aeration chamber to raise the liquid in the first aeration chamber while expelling CO2 in the liquid and at the same time supplying oxygen; A cylindrical body that forms a settler for receiving the liquid that has passed through and separating bubbles in the liquid, and a second aeration chamber that has a lower end connected to the settler and an upper end connected to the inside of the processing tank. a cylindrical body, a diffuser for dissolving oxygen in the liquid while raising the liquid in the second aeration chamber by blowing oxygen-containing gas into the second aeration chamber, and a diffuser formed at the peripheral edge of the processing tank. and a sludge pipe having one end opened into the separation chamber, the separation chamber having a lower end communicating with the inside of the treatment tank to receive the liquid in the treatment tank, and an upper end communicating with the inside of the treatment tank. A sewage purification device characterized in that a weir is formed for overflowing the supernatant liquid, and one end of the sludge pipe opens into a sludge layer separated in the separation chamber. 2. The sewage purification device according to claim 1, wherein the other end of the sludge pipe communicates with the bottom of the second aeration chamber. 3. The sewage purification device according to claim 1, wherein the other end of the sludge pipe opens at the bottom of the treatment tank.