JPS5843988Y2 - Sewage purification equipment - Google Patents

Description

[Detailed description of the invention] This invention relates to a sewage purification device using the gravity return method.

Conventionally, this type of purifying apparatus has been constructed as shown in FIG.

1 is an aeration tank, and an aerator 2 is installed in this aeration tank 1.
is provided.

3 is a sedimentation tank that is partitioned from the aeration tank 1 by a partition wall 5 and communicated with the aeration tank 1 by a bottom thrower I-4.

In this case, in order to keep the sedimentation tank 3 as still as possible and to smoothly return the sludge from the sedimentation tank 3, the slot 4 has a narrow and long shape, and the bottom of the sedimentation tank 3 is also formed on a slope. It is sandwiched between throwers 1 to 4.

Therefore, in the case of this configuration, there is a drawback that when the return operation is stopped even temporarily, the thickened sludge bridges and blocks the slot 4.

This invention was made to eliminate these drawbacks, and by drawing out the sludge at the bottom of the sedimentation tank using a return pump and returning it to the aeration tank, it is possible to prevent bridging of the slots and to prevent the return of sludge. The purpose of this invention is to provide a reliable sewage purification device.

Hereinafter, one embodiment of this invention will be described in detail with reference to FIGS. 2 to 4.

In FIG. 2, the configuration of each part indicated by reference numerals 1 to 5 is completely the same as the configuration shown in FIG. 1 above.

6 is an auxiliary pump for returning sludge, and has a suction pipe 7 opened at the bottom of the sedimentation tank 3 and a discharge pipe 8 opened at the top of the aeration tank 1.

In this case, it is preferable that the open end of the suction pipe 7 be located above the depth of the water in the slot 4 by about a spring.

Further, by opening the open end of the suction pipe 7 at only one location in the slot 4, a sufficient effect can be obtained in combination with gravity return.

Therefore, if the auxiliary pump 6 is now driven, the sedimentation tank 3
The crosslinked sludge at the bottom is suitably sucked up and returned to the aeration tank 1, thereby preventing the slot 4 from clogging.

The upper auxiliary pump 6 in this case may be any device as long as it can return the sludge; for example, an advection device as shown in FIG. 3 may be employed.

In other words, 10 is a sealed container that is installed submerged in water.
An air supply pipe 20 connected to a blower (not shown) is connected to the upper part of the airtight container 10, and an upper end of a suction pipe 30 whose lower end is opened underwater is connected to the upper part of the airtight container 10. A lower end of the discharge pipe 40 extending above the water surface level WL is connected to the air supply pipe 2, and a U-shaped pipe 50 is provided, and the upper end of one pipe portion 5A is connected to the air supply pipe 2.
0, and communicates the upper end of the other pipe portion 5B with the discharge pipe 40 at a level LA that is approximately equal to the level of communication between the suction pipe 30 and the closed container 10. The level LB of the lower end of the U-shaped tube 50 is set slightly above the communication level LC between the discharge tube 40 and the closed container 10.

Note that HWL and LWL indicate the highest water level and lowest water level, respectively, within the closed container 10, and as will be clear from what will be described later, respectively, coincide with the levels LA and LB.

Since this advection device has the above-described configuration, water is pumped up by operating as follows.

That is, at the start, before the blower connected to the air supply pipe 20 is driven, as shown in FIG. It is filled to the matching level.

When the blower is activated, the pressure of the air sent through the air supply pipe 20 increases the water level in the closed container 10 and simultaneously increases the water level in one pipe section 5 of the U-shaped pipe 50, as shown in FIG. 4B.
The water level in A is lowered by H1 from the water surface level WL, and in this state, the water pressure and the atmospheric pressure become equal.

As air continues to be supplied, the water level in the closed container 10 and one pipe portion 5A of the U-shape 50 further decreases, as shown in FIG. The water level in the suction pipe 30 decreases.

The water level in the discharge pipe 40 rises to a level where the difference H2 with the water level in the closed container 10 is equal to the difference H2' between the water surface level WL and the water level in the discharge pipe 30. Water begins to be discharged from the tip opening of the discharge pipe 40 provided at this level position.

By further supplying air, fresh water is discharged so that the water level in one pipe portion 5A of the U-shaped pipe 50 exceeds the level LB, as shown in the fourth diagram.

The difference H3 between the water level in the discharge pipe 40 and the water level in the closed container 10 at this time is also equal to the difference H3' between the water surface level WL and the water level in the suction pipe 30.

As described above, water is pumped up by the pressure of the air from the air supply pipe 20, but when the water level in one pipe section 5A of the U-shaped pipe 50 falls below the level LB, a U-shaped flow occurs as shown in FIG. 4E. Air forms bubbles from the other pipe portion 5B of the pipe 50 and rises inside the discharge pipe 40, thereby eliminating the high pressure state inside the closed container 10, so that the water inside the discharge pipe 40 flows into the closed container 10.
As the water returns to the inside, the water level in the suction pipe 30 begins to rise due to water pressure, and then the U-shaped pipe 50 and the discharge pipe 40 become empty as shown in FIG. Since water is released to the outside and the inside of the sealed container 10 is in communication with the outside atmosphere, water flows into the sealed container 1 through the suction pipe 30.
Flows into 0.

After the water level in the sealed container 10 rises together with the water level in the discharge pipe 40 and reaches the level LA as shown in FIG. Water overflows into the other pipe portion 5B, cutting off communication with the outside of the air supply pipe 20, and the water level rises until the water pressure inside the closed container 10 and the air pressure due to the supplied air are in equilibrium.

This equilibrium state is the state shown in FIG. 4B, and therefore the above-described series of operations is repeated again.

In one cycle of the above operation, a certain amount of water is always pumped out from the state shown in Fig. 4B to the state shown in Fig. 4. Therefore, the amount of water pumped on a time-averaged basis is constant, and has extremely high quantitative properties. is obtained.

Further, in this advection device, since the suction pipe 30 sucks the thickened sludge intermittently, the impact at that time effectively acts to break the crosslinks of the thickened sludge or prevent the crosslinking phenomenon.

As described above, according to this invention, the required amount of sludge is returned to the aeration tank from the bottom of the sedimentation tank using the gravity return method using the sludge return auxiliary pump, and therefore the following more beneficial effects are achieved.

(1) Bridging and clogging phenomena caused by sludge in the slot can be prevented, and sludge can be returned reliably.

(2) Even if the return flow rate is slightly or too high, it does not disturb the inside of the sedimentation tank, and if the flow rate is too high, the sewage in the aeration tank is sucked and circulated through the slot portion.

(3) Even if the return flow rate is low, there is no accumulation of sludge because gravity return is assisted.

(4) The sludge level can be lowered.

(5) In small-scale septic tanks, there is no small pump that can handle the amount of sludge returned, but if this return pump is used in intermittent operation with a timer, the entire amount of sludge that needs to be returned can be reliably returned. I can do it.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a conventional sewage purification device, FIG. 2 is a sectional view of a sewage purification device according to an embodiment of this invention, FIG. 3 is a sectional view of its main parts, and FIG. 4A- H is an explanatory diagram of the operation of the same main part. 1...Aeration tank, 2...Aerator, 3
...Sedimentation pond, 4...Slot, 6...
····pump.

Claims (2)

[Scope of utility model registration request] (1) an aeration tank, communicated with the aeration tank at the bottom;
A settling tank which receives the liquid in the aeration tank through the bottom communication part and performs sedimentation treatment, discharges the supernatant liquid, and returns settled sludge through the bottom communication part, and has one end opened at the bottom of the settling tank. , and a sludge return pump whose other end is opened at the upper part of the aeration tank and returns the settled sludge from the settling tank to the aeration tank. (2) As a sludge return pump, an airtight container installed below the liquid level, an air supply pipe communicating with this airtight container, a suction pipe communicating with the upper part of the airtight container, and a lower part of the airtight container communicating with the airtight container. A sewage purification device according to claim 1, which is a registered utility model and uses a convection device comprising a discharge pipe and a U-shaped pipe whose one end communicates with the upper part of the airtight container and whose other end communicates with the discharge pipe.