JP3025155B2 - Air lift pump for septic tank - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention provides an air lift pipe which can be erected in a septic tank, and a connection port for connecting a horizontal pipe capable of transporting water to be treated in the septic tank at an upper portion of the air lift pipe. The present invention also relates to an air lift pump for a septic tank having an air supply port at the lower part of the air lift pipe to which an air supply device can be connected.

[0002]

2. Description of the Related Art Generally, in a septic tank, it is desirable to maintain the water treatment environment as constant as possible in order to maintain the quality of treated water discharged at a constant level. Therefore, conventionally, in the septic tank, means for returning treated water and means for transferring treated water have been incorporated in order to perform stable treated water treatment, and such means for returning and treating treated water have been incorporated. As such, an air lift pump that can be operated with low electric power and has a small volume and a simple structure that is closed in the septic tank is used. Formed. That is, in the return pipe A of the water to be treated as shown in FIG. 5, as the air is supplied from the air supply port 2 to the air lift pipe 1, the bubble b rises in the air supply pipe 1 and The ascending flow a1 of the treated water is formed, and the treated water is pumped above the water level in the septic tank. The structure was such that it could be returned to the water treatment tank.

[0003]

On the other hand, in an aerobic treatment tank such as a contact aeration tank or a membrane separation tank in a septic tank, a floating substance as a load is reduced to an anaerobic treatment tank as much as possible in order to increase the nitrification efficiency. It is also desirable to return the treated water to the membrane separation tank and to discharge the treated water to the outside of the septic tank in order to keep the quality of the treated water constant. It is desirable to keep the transfer rate of treated water as constant as possible.

When a conventional air lift pump is used as a return pipe A for returning water to be treated from a contact aeration tank of a septic tank to an anaerobic filter bed tank, bubbles supplied from an air supply port 2 below the air lift pipe 1 are: In the process of rising inside the air lift tube 1, there is a case where the air bubbles collect and grow into large bubbles, and the flow rate of the to-be-treated water when the large bubbles rise inside the air lift tube 1 is a steady flow obtained by the small bubbles. The flow velocity is larger than the typical flow velocity, and with the rise, large bubbles greatly push up the surface of the water to be treated in the air lift pipe 1, which may cause abnormal pumping of the water to be treated at the upper part of the air lift pipe 1 ( (See the broken line in FIG. 5). If the water level in the air lift pipe 1 fluctuates due to the abnormal pumping, the water pressure at the air supply port 2 fluctuates due to the influence, and the blowing of the air bubbles b into the air lift pipe 1 becomes uneven, and large air bubbles are easily generated. Therefore, the flow rate of the water to be returned and the water to be returned to the contact aeration tank greatly fluctuates, and it is difficult to keep the water to be returned to the anaerobic filter bed tank constant. At the same time, bubbles are mixed into the returned water to be treated, and a large amount of oxygen is supplied to the anaerobic filter tank, so that the water treatment environment in the anaerobic filter tank changes aerobically, There was a possibility that adverse effects such as a decrease in water treatment performance would occur. Further, in order to prevent air bubbles from being mixed into the returned water to be treated, means for removing air bubbles from the water to be treated must be taken, such as providing a gas-liquid separation chamber in the return pipe A. A itself must be large, and the septic tank itself becomes large in order to accommodate the large return pipe A, resulting in inconvenience that the construction of the septic tank requires great expense. In addition, in the actual situation where the entire treatment in a limited space is necessary, the space occupied in the septic tank becomes large when the gas-liquid separation chamber is provided, and the inconvenience occurs when inspecting the inside of the tank. Will happen. For this reason, the advantages of the air lift pump conventionally used for low power and small volume cannot be utilized.

[0005] When the abnormal pumping occurs, the amount of the water to be returned is increased, and the environment in which the water to be processed circulates in the septic tank changes. When the circulating amount of the water to be treated increases, the sludge component easily flows into the contact aeration tank, thereby increasing the load of the contact aeration tank to lower the water treatment performance, or disturbing a large amount of nitrifying liquid. It is considered that the wastewater is returned to the filter tank at one time and adversely affects microorganisms in the anaerobic filter tank.

The same can be said for the case where the air lift pump is used for the transfer pipe of the water to be treated and the case where the air lift pump is used for the discharge pump for discharging the treated water out of the septic tank. If a large amount of water to be treated flows into the downstream water treatment tank, sludge components are likely to be transferred, so the load on the downstream water treatment tank is increased and normal water treatment performance is exhibited. When used as a discharge pump for discharging treated water outside the septic tank,
There is a concern that the quality of the treated water discharged outside the septic tank will be reduced, leading to environmental pollution in the surrounding area. Therefore, an air lift pump in which the water level in the air lift pipe 1 hardly fluctuates has been desired.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an air lift pump in which the amount of water to be treated is less varied in view of the above circumstances.

[0008]

In order to achieve the above object, a feature of the present invention is to provide an air lift pipe which can be erected in a septic tank, and the water to be treated in the septic tank can be transferred above the air lift pipe. And a connection port through which a flexible horizontal pipe can be connected, and an air lift pump for a septic tank provided with an air supply port at the lower part of the air lift pipe where an air supply device can be connected, wherein the upper surface of the air lift pipe below the connection port Is formed on the uneven surface, and the operation and effect are as follows.

[0009]

In other words, in the air lift pipe, the flow of the water to be treated is disturbed by the uneven surface, and turbulent flow is easily formed. Therefore, large bubbles are generated in the air lift pipe, and the upward flow of the water to be treated is faster than usual. Even if it occurs, when the bubbles reach the water level in the air lift pipe, the turbulent flow tends to reduce the flow velocity of the water to be treated, and the turbulent flow may cause large bubbles to be small and shredded. By suppressing the flow velocity of the water and shredding the bubbles, the rising speed of the bubbles when reaching the water surface is suppressed, and it becomes difficult to greatly push up the water surface in the air lift pipe.

[0010]

Therefore, in the air lift tube, abnormal pumping is unlikely to occur, and the water level can be easily maintained at a constant constant position. Therefore, it is possible to provide an air lift pump for a septic tank that can maintain a high water treatment performance and has a very small possibility of adversely affecting the surrounding environmental pollution while taking advantage of the air lift pump conventionally used for low power and small volume. It became so.

Further, if the upper portion of the air lift pipe is constituted by a large-diameter enlarged portion, the water to be treated is diffused when the water to be treated rises from the lower portion of the air lift tube to the enlarged portion. Since the rising speed is suppressed, it also works to suppress the flow rate of the water to be treated. The uneven surface is formed as a ring-shaped convex portion along the pipe circumferential direction on the inner surface of the upper portion of the air lift tube, and if the uneven surface is formed, the forming of the air lift tube is easy, and Since the turbulence tends to work in the direction of suppressing the flow velocity of the water to be treated, it is easy to maintain a constant constant water level. A ring-shaped convex portion is provided on the inner surface of the enlarged diameter portion along the pipe circumferential direction, and the minimum diameter of the convex portion in the pipe is formed larger than the internal diameter of the lower portion of the air lift pipe. It is easy to maintain the pumping power of the water to be treated from the lower part, and there is no inconvenience that the horizontal pipe installation position must be changed due to a decrease in the pumping power and a drop in the water level in the air lift pipe. There is an advantage that the air lift pump can be installed without changing the internal configuration and the like.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. As shown in FIG. 2, from the upstream side, the anaerobic filter bed tank 1
An anaerobic filter tank N comprising a chamber N1 and an anaerobic filter tank second chamber N2, a contact aeration tank E, a sedimentation tank P, and a disinfection tank Q are provided so that the liquid to be treated flows in this order by natural advection to form a purification tank. I have. The air lift pump of the present invention is used in a return path A for returning treated water from the contact aeration tank E to the first anaerobic filter bed tank N1.

In the anaerobic filter bed tank N, an anaerobic microorganism for anaerobically decomposing organic substances in the liquid to be treated and denitrifying nitrate nitrogen grows, and a filter bed F for fixing the biofilm.
1 and F2 are provided in the anaerobic filter bed first chamber N1 and the anaerobic filter tank second chamber N2, respectively.

The contact aeration tank E is provided with a contact material C for fixing aerobic microorganisms for decomposing the remaining organic substances in the liquid to be treated and nitrifying ammoniacal nitrogen. A diffuser tube D that generates a circulating flow, makes the aerobic microorganisms fixed to the contact material C well contact the water to be treated containing organic matter, and supplies air for giving necessary oxygen to the aerobic microorganisms. It is provided.

Further, in order to prevent clogging due to excessive attachment of a biofilm or the like to the contact material C, air bubbles are released and collided with the contact material C, and excess biofilm or the like is converted into exfoliated sludge. A backwash pipe R for peeling is provided below the contact material C, and the suspended sludge in the contact aeration tank E is increased due to the peeled sludge, so that the BOD is not excessively increased. In order to denitrify in the filter bed tank first room N1,
A return path A is provided for returning the separated sludge and the water to be treated containing the nitrification liquid to the first anaerobic filter bed tank N1.

As shown in FIG. 1, the return path A is provided with an air lift pipe 1 which can be erected in a septic tank, and an air supply port 2 which can be connected to a blower Bw below the air lift pipe 1. An enlarged portion 1a is formed at the upper portion of the air lift tube 1 and is connected to the lower portion of the air lift tube 1 via a tapered portion 1b. A connection port 4 is provided in the enlarged diameter portion 1a so that a horizontal pipe 3 that can be returned to the outside can be connected. An inner surface below the connection port 4 of the enlarged diameter portion 1a is formed into an uneven surface by forming a ring-shaped convex portion 5 along a pipe circumferential direction, and the minimum diameter d1 of the convex portion 5 is equal to the air lift pipe 1. The lower inner diameter d2 is slightly larger than the inner diameter d2.

Therefore, when air bubbles are supplied from the air supply port 2, the air bubbles rise and form an ascending flow a1 of the water to be treated, which flows into the enlarged diameter portion. The water to be treated that has flowed into the enlarged diameter portion spreads along the tapered portion 1b, and
To form a turbulent flow a2. Even if a large bubble is generated, the large bubble reduces the resistance due to the turbulent flow.
Receiving , the rising speed is reduced or shredded. As a result, the force of the water to be treated to push up the water surface is weakened, so that the fluctuation of the water level in the air lift pipe can be suppressed to a small value.

A lid 6 having a vent 6a is attached to the upper opening 1c of the enlarged diameter portion 1a.

The horizontal pipe 3 is formed with an enlarged diameter portion 3a. Even if abnormal pumping occurs in the air lift pipe 1, a notch 3b for returning excess water more than necessary to the contact aeration tank E.
A baffle plate 3c is provided on the upstream side of the notch portion 3b for passing only the liquid to be treated having a small amount of bubbles to reduce the waving of the liquid surface, and also on the downstream side of the notch portion 3b. A baffle plate 3d is provided to reduce fluctuations in the amount of liquid to be transferred.

The baffle plates 3c and 3d are provided with openings 3e and 3f at the lower part of the liquid layer, so that the liquid is hardly affected by the waves even if the large-diameter portion 1a of the air lift tube 1 has large undulations. It is configured such that a subsurface static flow a3 flows from the enlarged diameter portion 1a to the horizontal pipe 3.

Therefore, the water to be treated which has flowed in from the inlet I is circulated through the return path while being purified in the anaerobic filter tank N and the contact aeration tank E, and is highly purified.
The treated water treated in the above is transferred from the bottom of the contact aeration tank E to the sedimentation tank P, and the supernatant of the sedimentation tank P overflows and is guided to the disinfection tank Q, where it contacts the solid disinfectant. Each tank is formed so as to be discharged from the discharge port Z after being disinfected.

With the above configuration, the flow rate of the liquid to be returned to the anaerobic filter bed tank N1 can be easily adjusted, the flow rate of the liquid to be treated and the oxygen content can be stabilized, and the biological treatment can be stabilized only by providing the small return path A. Can be performed.

[Another Embodiment] Another embodiment will be described below.
In the above embodiment, the concave-convex surface is formed of the ring-shaped convex portions 5 along the circumferential direction of the tube. However, the present invention is not limited to this. Any configuration may be used as long as the resistance is such that large bubbles that rise quickly and vigorously rise.

The air lift pump as described above has a characteristic that it is easy to maintain a constant flow rate by suppressing the fluctuation of the flow rate due to abnormal pumping. Therefore, not only the return pipe but also the settling tank P to the disinfection tank Q
And a transfer pipe for quantitatively transferring the water to be treated to a membrane separation tank.

In the claims, reference numerals are provided for convenience of comparison with the drawings, but the present invention is not limited to the configuration shown in the attached drawings.

[Brief description of the drawings]

FIG. 1 is a sectional view of an air lift pump of the present invention.

FIG. 2 is a vertical side view of a septic tank.

FIG. 3 is a sectional view of a main part in another embodiment.

FIG. 4 is a sectional view of a main part in another embodiment.

FIG. 5 is a sectional view of a conventional air lift pump.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Air lift pipe 1a Large diameter section 2 Air supply port 3 Horizontal pipe 4 Connection port 5 Convex part Bw Air supply device

Continuing from the front page (72) Inventor Kazuyuki Honda One at 2 Takamatsu, Kosai-cho, Koga-gun, Shiga Prefecture Inside the Kubota Shiga Plant (72) Katsumi Hamada Two-stock, Takamatsu, Kosai-cho, Koga-gun, Shiga Prefecture Kubota Corporation Shiga Factory (56) References JP-A 4-78997 (JP, U) JP-A 4-26100 (JP, U) (58) Fields surveyed (Int. Cl. ⁷ , DB name) F04F 1 / 18

Claims (3)

(57) [Claims] 1. An air lift pipe which can be erected in a septic tank is provided, and a connection port for connecting a horizontal pipe capable of transferring water to be treated in the septic tank is provided above the air lift pipe, and a connection port is provided below the air lift pipe. a air lift pump septic tank the air supply device is provided with a freely air supply port connections, it said enlarged diameter portion having a larger diameter than the air-lift pipe lower Airy
At the top of the shaft and below the connection port
An air lift pump for a septic tank having an uneven surface formed on the inner surface of the enlarged diameter portion . 2. A ring-shaped projection (5) extending in a circumferential direction of a pipe.
2. An air lift pump for a septic tank according to claim 1, wherein a surface of the air lift pipe (1) is formed on an upper inner surface of the air lift pipe (1) to constitute the uneven surface. 3. A ring-shaped convex portion (5) is provided on an inner surface of the enlarged diameter portion (1a) along a pipe circumferential direction, and a minimum diameter of the convex portion (5) in the pipe is set to the air lift pipe (1). The air lift pump for a septic tank according to claim 2, wherein the air lift pump is formed to be larger than the inner diameter of the lower pipe.