JP2989480B2 - Air lift pump for septic tank - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention has an air lift pipe installed upright 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. An air lift pump that can be operated with low power, has a small volume in the septic tank, and has a simple configuration is used to mitigate the impact of liquid that rises with air bubbles and keep the amount of water to be pumped constant. In order to maintain the float, a float capable of moving up and down below the water surface was provided above the airlift pipe. That is, as shown in FIG. 3, 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 forms an upward flow a1 of the water to be treated. A configuration is adopted in which the treated water is pumped above the water level in the septic tank, and the water to be treated can be returned to the water treatment tank on the upstream side of the septic tank from the connection port 4 for the horizontal pipe 3 formed above the air lift pipe 1. Yes (for example, the structure is such that the water to be treated in the contact aeration tank is returned to the anaerobic filter tank), and a return pipe A for treating water provided with a columnar float 5 above the air lift pipe 1 is considered. Was.

[0003]

According to the above-mentioned conventional return pipe A, the float 5 reduces the force of bubbles rising in the upper part of the air lift pipe 1, whereby the air flow in the air lift pipe 1 is reduced. Since the flow rate of the treated water is suppressed, abnormal water pumping in which the water level in the air lift pipe 1 rises abnormally is relieved, but large bubbles generated due to aggregation of small bubbles as the air lift pipe 1 rises Reached the water surface while remaining large, and the large bubbles sometimes raised the water level in the air lift pipe 1 greatly. Therefore, it has been considered that abnormal pumping also occurs in the air lift pipe 1 and the amount of water to be treated returned from the return pipe fluctuates greatly.

[0004] In addition, the above-mentioned phenomenon includes that the float
There was also a question that the resistance was caused when the bubbles rose, and this was partly due to the promotion of the aggregation and growth of the bubbles.

When the water level in the air lift pipe 1 fluctuates due to abnormal pumping, the water pressure at the air supply port 2 fluctuates due to the influence, and the blowing of bubbles b into the air lift pipe 1 becomes non-uniform, resulting in large bubbles. Because of the vicious circulation that occurs, the fluctuation of the flow rate of the water to be returned and the water to be returned to the contact aeration tank becomes large, and the water to be returned to the anaerobic filter tank is kept constant. Is difficult, and bubbles are mixed in the water to be returned, which causes a large amount of oxygen to be supplied to the anaerobic filter tank. Therefore, the water treatment environment in the anaerobic filter tank changes aerobically. However, there is a possibility that adverse effects such as a decrease in water treatment performance may occur. Further, in order to prevent air bubbles from being mixed into the water to be returned, it is necessary to take measures to remove air bubbles from the water to be processed, such as providing a gas-liquid separation chamber in the return pipe A.
The return pipe A itself must be large, and the septic tank itself must be large in order to accommodate the large return pipe A, resulting in inconvenience that the construction of the septic tank requires a large cost. . In addition, in the actual situation where the entire treatment is required in a limited space, the space occupied in the septic tank becomes large if the gas-liquid separation chamber is provided, and the inconvenience when inspecting the inside of the tank is obstructed. Will happen. For this reason, the advantages of the air lift pump conventionally used for low power and small volume cannot be utilized. Further, 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-mentioned drawbacks.

[0008]

In order to achieve this object, the present invention is characterized in that an air lift pipe is erected in a septic tank, and a horizontal portion capable of transferring the water to be treated in the septic tank is provided above the air lift pipe. In a septic tank air lift pump having a connection port capable of connecting a pipe and an air supply port capable of connecting an air supply device below the air lift pipe, a cover for covering an upper opening of the air lift pipe is provided. The air vent hole is formed in the lid body, and the lid is attached to the upper opening of the air lift pipe, and the tip is located below the connection port in the air lift pipe. A stay is attached to the lid, and the tip has a fixed object for defoaming formed by forming a large number of holes penetrating from front to back, and the defoaming object is
It may be a stainless steel wire mesh, and it is more preferable that the stay has a movable plate attached slidably along the stay with the lid attached to the upper opening of the air lift tube. An enlarged portion having a larger diameter than the lower portion of the air lift tube may be formed in the upper portion of the air lift tube, and the operation and effect thereof are as follows.

[0009]

[Operation] In other words, even if a large bubble is generated in the air lift pipe by the above-mentioned characteristic configuration, the large bubble is
As it collides with the defoaming object and passes through a large number of holes penetrating from the front to the back, large bubbles are shredded and become small bubbles to reach the water surface, and the rising speed of the water to be treated also decreases. Since the water surface in the air lift pipe does not rise significantly because it falls due to collision with the object for use, abnormal pumping becomes difficult to occur, so that the transfer amount of the water to be treated has become stable.

[0010] Further, since the defoaming object is fixed to the lid via the stay, maintenance can be performed simply by removing the lid, and inconvenience due to clogging of the defoaming object is hardly caused. Thus, the defoaming function of the defoaming object is easily maintained.

[0011]

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, various inconveniences caused by the fluctuation of the transfer amount of the water to be treated can be solved,
Conventionally, water treatment performance can be maintained high while taking advantage of the air lift pump adopted for low power and small volume.
It has become possible to provide an air lift pump for a septic tank that is extremely unlikely to adversely affect surrounding environmental pollution.

In addition, if the defoaming object is a stainless steel wire mesh, a high defoaming function is exhibited, shape retention is good, and the lid is attached to the upper opening of the air lift pipe. Then, if a movable plate slidable along the stay is attached, even if a large bubble has passed from the defoaming object, the large bubble pushes up the water surface with the movable plate. If the enlarged portion having a larger diameter than the lower portion of the airlift tube is formed at the upper portion of the airlift tube, the flow of the water to be treated is diffused at the enlarged portion, and the force of the flow is weakened. In addition, it is possible to suppress the flow of the water to be treated from greatly pushing up the water surface, and it is possible to suppress the fluctuation of the transfer amount of the water to be treated.

[0013]

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 bed tank N comprising a chamber N1 and an anaerobic filter bed 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, anaerobic microorganisms that perform anaerobic decomposition of organic substances in the liquid to be treated and denitrify nitrate nitrogen grow, 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 to remove excess biofilm and the like. In addition to providing a backwash tube R below the contact material C for peeling off as well as preventing the suspended sludge from increasing in the contact aeration tank E due to the peeling sludge and increasing the BOD, and In order to denitrify the liquid in the first anaerobic filter tank N1, a return path A for returning the exfoliated sludge and the water to be treated containing the nitrification liquid to the first anaerobic filter tank N1 is provided.

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.

A vent 6 is provided above the enlarged diameter portion 1a.
The lid 6 formed with a is attached.

The front cover 6 is attached to the cover 6 with the enlarged diameter portion 1.
a base end of a stay 7 is attached to the inside of the airlift pipe in a state of being screwed on the upper portion of the stay a, and a stainless steel wire mesh 8 as a defoaming object is fixed substantially horizontally to the tip side of the stay 7. It is. A movable plate 9 is slidably provided along the stay 7 near the center of the stay 7 in the longitudinal direction.
Is held. In a state where the lid 6 is screwed on the upper portion of the enlarged diameter portion 1a, the wire mesh 8 is immersed and fixed in the water to be treated in the enlarged diameter portion 1a, and the movable plate 9 is The posture is slightly above the surface of the water to be treated.

The horizontal pipe 3 has a large-diameter portion 3a formed therein, and 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 3b for passing only the liquid to be treated with less bubbles to reduce the waving of the water surface, and transferred to the downstream side of the notch 3b. A baffle plate 3d for reducing fluctuations in the amount of liquid to be treated is provided.

Therefore, when the air bubbles b are supplied from the air supply port 2, the air bubbles b collect and grow as the air lift pipe 1 rises to become large bubbles B. 8 and is shredded into small bubbles b, and ascending speed decreases, so that the water to be treated disappears on the surface of the water without being pushed up too much.
The water surface in the enlarged diameter portion 1a hardly undulates.
Also, even if the large bubble B reaches the water surface,
Since the large bubble B collides with the movable plate 9 and disappears, the water surface in the enlarged diameter portion 1a is almost no longer wavy. The gas component from the disappeared air bubbles is discharged from the air holes 6a and the notches 3b to the outside of the air lift pump.

The baffle plates 3c and 3d are provided with openings 3e and 3f at the lower portion of the liquid layer portion, and are 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 difficult submerged static flow flows from the enlarged diameter portion 1a to the horizontal pipe 3.

The treated water that has been treated in the contact aeration tank E is transferred from the bottom of the contact aeration tank E to the sedimentation tank P.
The supernatant liquid overflows and is led to the disinfecting tank Q, where it is sterilized by contact with a solid disinfectant, and then discharged from the discharge port Z to form each tank.

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 a small return path A. Can be performed.

[Another Embodiment] Another embodiment will be described below.
In the previous embodiment, the defoaming object was made of a stainless steel wire mesh, but it may be a perforated plate or a perforated metal, and furthermore, a resin net, a perforated plate, or a ceramic perforated plate. Obstacles formed by forming a large number of through holes on the front and back surfaces may be collectively referred to as defoaming objects.

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.

[0027] In the claims, reference numerals are written for convenience of comparison with the drawings, but the present invention is not limited to the configuration of the attached drawings by the entry.

[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 conventional air lift pump.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Air lift pipe 1a Large diameter part 2 Air supply port 3 Horizontal pipe 4 Connection port 6 Lid 7 Stay 8 Wire mesh 9 Movable plate Bw Air supply device

──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Kazuyuki Honda 1 at 2, Takamatsu, Kosai-cho, Koga-gun, Koka-gun, Shiga Prefecture Inside the Kubota Shiga Plant (72) Katsumi Hamada 2, Takamatsu, Kosai-cho, Koga-gun, Shiga 1 Kubota Corporation Shiga Factory (56) References JP-A 4-78993 (JP, U) JP-A 61-70599 (JP, U) JP-A 4-78997 (JP, U) (58) Survey Field (Int.Cl. ⁶ , DB name) F04F 1/18

Claims (4)

(57) [Claims] An air lift pipe (1) is erected in a septic tank, and a horizontal pipe (3) capable of transporting water to be treated in the septic tank is connected to a connection port (4) above the air lift pipe (1). ), And an air lift pump for a septic tank provided with an air supply port (2) that can be connected to an air supply device (Bw) below the air lift pipe (1). Lid (6) that covers the upper opening
So that the tip is located below the connection port (4) in the air lift tube (1) in a state where the lid (6) is attached to the upper opening of the air lift tube (1). An air lift pump for a septic tank, wherein a stay (7) is attached to the lid (6), and an antifoaming object (8) having a large number of holes penetrating from the front to the back is fixed to the tip. 2. The air lift pump for a septic tank according to claim 1, wherein the defoaming object (8) is a metal mesh (8) made of stainless steel. 3. The stay (7) is provided with the lid (6).
The movable plate (9) is slidably slid along the stay (7) in a state where is attached to the upper opening of the air lift tube (1).
The air lift pump for a septic tank according to any one of claims 1 and 2, further comprising: 4. The air lift pump for a septic tank according to claim 1, wherein an enlarged portion (1a) having a larger diameter than the lower portion of the air lift tube (1) is formed at an upper portion of the air lift tube (1).