JPH0957262A - Method for dissolving air in treated water in septic tank and septic tank - Google Patents

Abstract

(57) Abstract: To provide a technique capable of air-dissolving in a membrane separation tank with a simple configuration. SOLUTION: A plurality of water treatment tanks are provided, at least one of the water treatment tanks is composed of a membrane separation tank E2, and the treated water is transferred to a water treatment tank different from the membrane separation tank E2. And a mechanical pump P2 for water, and a septic tank in which a transfer pipe A2 for transferring water to be treated from a water treatment tank different from the membrane separation tank E2 to the membrane separation tank E2 is connected to the mechanical pump P2. In the method for dissolving air in the water to be treated, the bubbles are supplied to the transfer pipe A2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a septic tank comprising a plurality of water treatment tanks, at least one of which is a membrane separation tank. The present invention relates to a septic tank in which air is dissolved, or a method for dissolving air in water to be treated in the septic tank.

[0002]

2. Description of the Related Art Conventionally, in this type of septic tank, a mechanical pump for transferring treated water is simply provided in a water treatment tank different from the membrane separation tank, and the treated water is separated from the membrane separation tank. It is known that the transfer pipes that transfer from different water treatment tanks to the membrane separation tank are connected to the mechanical pump or the air lift pump, and in the normal membrane separation tank, advanced treatment with activated sludge is performed, Although a large amount of dissolved oxygen (hereinafter abbreviated as DO) is required, such a DO supply to the water to be treated in the septic tank is provided with an air diffuser pipe for circulating the water to be treated in the membrane separation tank. It was done by air dissolution by air bubbles from the trachea.

[0003]

However, according to the above-mentioned septic tank, the amount of air dissolved based on the picture supply from the air diffuser increases as the height of the septic tank (more precisely, the water depth of the air diffuser) increases. However, since septic tanks are usually buried underground, increasing the height of septic tanks causes the inconvenience of construction costs and process labor, such as having to dig deep into the septic tank embedding pit to construct septic tanks. Therefore, there is a current situation that it cannot be increased unnecessarily, and it is possible to increase the oxygen dissolution efficiency by making the air supply of the air diffuser into small bubbles, but it is easy to impair the originally required function of circulating the treated water. There was a problem.

Therefore, in view of the above situation, an object of the present invention is to provide a technique capable of air-dissolving in a membrane separation tank with a simple structure.

[0005]

[Means for Solving the Problems]

[Structure] The characteristic structure according to claim 1 of the present invention for achieving this object comprises a plurality of water treatment tanks, and at least one of the water treatment tanks is constituted by a membrane separation tank, A mechanical pump for transferring treated water is provided in a water treatment tank different from the membrane separation tank, and a transfer pipe for transferring the treated water from the water treatment tank different from the membrane separation tank to the membrane separation tank. In the method for dissolving air in treated water in a septic tank connected to the mechanical pump, bubbles are supplied to the treated water transfer pipe, and the effects thereof are as follows.

[Operation / Effect] That is, in the above-mentioned configuration, the mechanical pump for transferring the water to be treated simply transfers the water to be treated from the water treatment tank different from the membrane separation tank to the membrane separation tank. In addition, air bubbles are supplied into the treated water transfer pipe during the treatment water transfer, so that the treated water is air-dissolved in the treated water transfer pipe. Therefore, in the membrane separation tank, it tends to be in a state of being sufficiently air-dissolved in the water to be treated, activated sludge in the membrane separation tank is less likely to fall into oxygen deficiency, and stable activated sludge treatment can be performed, and the filtered water of the water to be treated is filtered. However, it has become fully biologically treated,
The quality of wastewater discharged to the outside is improved.

[Structure] The characteristic structure according to claim 2 of the present invention comprises a plurality of water treatment tanks, wherein at least one of the water treatment tanks is constituted by a membrane separation tank. An air lift pump for transferring treated water is provided in a water treatment tank different from the separation tank, and a transfer pipe for transferring the treated water from the water treatment tank different from the membrane separation tank to the membrane separation tank is the air lift pump. In the method of dissolving air in the water to be treated in the septic tank continuously provided, fine bubbles smaller than the bubbles for air lift are supplied to the transfer pipe, and the action and effect are as follows.

[Operation / Effect] That is, in the above-mentioned configuration, even if the pump for transferring the water to be treated is an air lift pump, normally, the bubbles supplied for the air lift are relatively large and relatively short time. Since it reaches the water surface, the oxygen dissolution efficiency becomes low, and the function of dissolving oxygen is hardly obtained, and conversely, there is a possibility that a bottom for air lift cannot be obtained with only fine bubbles. On the other hand, since the fine bubbles are supplied separately from the air-lifting bubbles, the air-dissolving function can be imparted while maintaining the air-lifting function. [Structure] The characteristic structure according to claim 3 of the present invention is as follows.
A plurality of water treatment tanks are provided, at least one of the water treatment tanks is composed of a membrane separation tank, and a mechanical pump for transferring treated water is provided in a water treatment tank different from the membrane separation tank. In addition, in a septic tank in which a transfer pipe that transfers water to be treated from a water treatment tank different from the membrane separation tank to the membrane separation tank is connected to the mechanical pump, bubbles can be freely supplied to the transfer pipe. Since the air supply device is provided, its function and effect are as follows.

[Operation / Effect] That is, since the transfer pipe is provided with an air supply device capable of supplying bubbles, the object to be treated in the septic tank according to claim 1 is simply added to the conventional septic tank. A suitable configuration can be obtained for the method of dissolving air in water. [Structure] The characteristic structure according to claim 4 of the present invention is as follows.
A plurality of water treatment tanks are provided, at least one of the water treatment tanks is a membrane separation tank, and an air lift pump for transferring water to be treated is provided in a water treatment tank different from the membrane separation tank. At the same time, in a septic tank in which a transfer pipe for transferring the water to be treated from a water treatment tank different from the membrane separation tank to the membrane separation tank is connected to the air lift pump, a supply air capable of supplying bubbles to the transfer pipe. Further, in addition to the characteristic structure according to claim 4, the device according to claim 5 of the present invention supplies fine air bubbles smaller than the air lift bubbles to the air lift pump. A free air supply device is provided, and its function and effect are as follows.

[Operations / Effects] That is, according to the above-mentioned configuration, since bubbles capable of easily dissolving air in the water to be treated can be supplied to the transfer pipe, even in the septic tank provided with the air lift pump, It is possible to suppress insufficient air dissolution. The finer the bubbles to be supplied by the air supply device, the longer the residence time in water, the larger the surface area per unit volume of the bubbles, and the higher the gas-liquid contact efficiency. This is advantageous because the efficiency is high.

[Structure] In addition to the characteristic structure according to any one of claims 3 to 5, the characteristic structure according to claim 6 of the present invention is a water treatment tank different from the membrane separation tank in the transfer pipe. The horizontal pipe portion is provided between the membrane separation tank and the membrane separation tank, and the air supply device is provided in the horizontal pipe portion. The function and effect are as follows.

[Operations / Effects] That is, if an air supply device is provided in the lateral pipe portion, the air supply device is arranged above the septic tank, and the maintenance of the air supply device is easy. Since there is no need to supply air against water pressure,
It requires less power to supply air.

As the air supply device, for example, an ejector is used. In this case, the power of the pump for transferring the water to be treated can be used to supply air into the transfer pipe by the ejector. Therefore, the mechanical pump is used. Alternatively, air can be supplied by using the treated water carrying force of the air lift pump, and the air dissolving efficiency can be efficiently improved by simply changing the configuration of the transfer pipe.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. As shown in FIG. 1, the septic tank of the present invention is divided into two parts of a cylindrical septic tank body X by providing inspection parts X1 and X2 at both ends to form a closed space inside and partition walls provided inside the closed space. Then, from the upstream side, a flow rate adjusting tank N, a denitrification tank E1, a membrane separation tank E2, and a discharge pump tank T are sequentially formed from the upstream side, and a manhole H used for maintenance or the like is formed above the respective tanks. Is provided.

The flow rate adjusting tank N receives the raw water of the water to be treated that has flowed into the septic tank from the inlet I provided in the one portion X1 of the septic tank main body X, and removes the impurities in the water to be treated. While removing the precipitate, anaerobic bacteria growing inside,
A first pump P1 for transferring the water to be treated to the denitrification tank E1 is provided in the water treatment chamber for temporarily storing the water to be treated while performing the anaerobic treatment of the water to be treated, Even when there is no inflow of the water to be treated for a long period of time, the water to be treated is constantly transferred to the denitrification tank E1 so as not to hinder the water treatment in each of the subsequent water treatment chambers.

The denitrification tank E1 is connected to the first pump P1 with an inflow pipe A1 for introducing water to be treated from the flow rate adjusting tank N into a water treatment chamber adjacent to the flow rate adjusting tank N. It is provided and constitutes an inflow path for the water to be treated. In addition, a second pump P2 is provided inside, and a transfer pipe A
2 is provided to transfer the water to be treated to the membrane separation tank E2. In addition, a stirring pump P4 that stirs and circulates the treated water in the tank is installed, and the treated water in the tank is mixed to mix the treated water having a high BOD load with the nitrified treated water. However, it is configured so that it can perform advanced denitrification processing.

The second pump P2 is an underwater immersion type mechanical pump (so-called submersible pump), and a vertical pipe 1 is connected to the second pump P2, and the desorption is provided on the upper portion of the vertical pipe 1. The transfer tube A2 is configured by connecting a horizontal tube 2 which is horizontally installed between the nitrogen tank E1 and the membrane separation tank E2, and air is sucked into the horizontal tube 2 to generate fine bubbles. An ejector 3A for supplying into the lateral pipe 2 is provided.

In the membrane separation tank E2, the inflow passage is provided in a partition wall that separates the denitrification tank E1 from the denitrification tank E1, and the water to be treated that has excessively flown into the denitrification tank E1 is supplied to the denitrification tank E1. A return port A4 for returning the water is provided to form a return path for the water to be treated. In addition, a membrane separation device M in which a large number of flat plate-shaped filtration membrane plates are arranged in parallel in an upright state is installed, and the membrane separation device M is a filtration device that holds a large number of filtration membrane plates in alignment. A membrane plate holding frame is provided, and a leg portion for supporting the filtration membrane plate holding frame is provided at the lower portion, and air bubbles are supplied to the filtration membrane plate between the leg portions so that sludge or the like adheres too much to the membrane surface. And a diffusing device D for supplying oxygen to the water to be treated while forming a circulating flow in the membrane separation tank E2. In addition, a water intake pipe M4 is connected to each of the filtration membrane plates of the membrane separation device M, and a water collection pipe M5 that joins the filtered water from the water intake pipe M4 and guides it to the outside of the membrane separation tank E1 is connected. Yes, it is connected to the discharge pump tank T adjacent to the membrane separation tank E2 below the water surface of the membrane separation tank E2.

The discharge pump tank comprises a disinfection tank Q1 and a storage tank Q2, and the disinfection tank Q1 is the membrane separation tank E.
2 and the discharge pump tank T are provided with a treated water receiving container on a partition wall, and a small hole is provided on the wall surface thereof. The filtered water flowing into the disinfecting tank Q1 is sterilized and then stored in the storage tank. It flows into Q2. The storage tank Q2 is a third pump P3.
After storing the treated water, the treated water is pumped up by the discharge pump P1 and discharged through the discharge pipe 5 to the discharge port Z.
It is configured so that it can be discharged to the outside of the septic tank. This allows
The disinfected treated water is discharged from the storage tank T to the outside of the septic tank almost quantitatively.

[Another Embodiment] Another embodiment will be described below. In the above embodiment, the transfer pump P2 is configured by a submersible mechanical pump (so-called submersible pump), but the present invention is not limited to this, and it may be configured by an air lift pump Pa. A2 is connected to the vertical pipe 1 to the second pump P2, and a horizontal pipe 2 is connected to the upper portion of the vertical pipe 1 so as to extend horizontally between the denitrification tank E1 and the membrane separation tank E2. And an ejector 3A for sucking air into the lateral tube 2 to supply fine bubbles into the lateral tube 2.
Although the vertical pipe 1 may be provided with an ejector, the air supply device 3 may supply air with a blower instead of the ejector 3A to supply fine air bubbles in the transfer pipe. It may be configured to send to. That is, it may be configured as shown in FIG. In FIG. 2, a vertical pipe for air lift is provided with an air supply unit 1a for supplying relatively large bubbles, and a supply unit 3B for supplying fine bubbles smaller than the bubbles, both of which are connected to a blower. is there.

It should be noted that reference numerals are added to the claims for convenience of comparison with the drawings, but the present invention is not limited to the configurations of the accompanying drawings by the entry.

[Brief description of drawings]

FIG. 1 is a vertical side view of a septic tank.

FIG. 2 is a vertical sectional side view of a septic tank according to another embodiment.

[Explanation of symbols]

 2 Horizontal pipe part 3 Air supply device 3A Ejector A2 Transfer pipe P2 Mechanical pump Pa Air lift pump E2 Membrane separation tank

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masahisa Iwahashi 1 share at 2 Takamatsu, Kosai-cho, Koga-gun, Shiga Prefecture Inside Kubota Shiga Factory (72) Inventor Katsumi Hamada 1 share at 2 Takamatsu, Kosai-cho, Koga-gun, Shiga Prefecture Kubota Shiga Factory

Claims (6)

[Claims] 1. A water treatment tank comprising a plurality of water treatment tanks, wherein at least one of the water treatment tanks comprises a membrane separation tank (E2), and the water treatment tank is different from the membrane separation tank (E2). , A transfer pipe (A2) which is provided with a mechanical pump (P2) for transferring treated water and transfers the treated water from a water treatment tank different from the membrane separation tank (E2) to the membrane separation tank (E2)
Is a method for dissolving air in the water to be treated in the septic tank connected to the mechanical pump (P2), wherein the air is dissolved in the water in the septic tank for supplying air bubbles to the transfer pipe (A2). 2. A water treatment tank comprising a plurality of water treatment tanks, wherein at least one of the water treatment tanks is composed of a membrane separation tank (E2), and the water treatment tank is different from the membrane separation tank (E2). An air lift pump (Pa) for transferring treated water is provided, and a transfer pipe (A) for transferring the treated water from a water treatment tank different from the membrane separation tank (E2) to the membrane separation tank (E2).
2) is a method for dissolving air in water to be treated in a septic tank connected to the air lift pump (Pa), wherein the transfer pipe (A2) supplies fine air bubbles smaller than air lift air bubbles. Method of dissolving air in water to be treated. 3. A water treatment tank comprising a plurality of water treatment tanks, at least one of said water treatment tanks being composed of a membrane separation tank (E2), which is different from said membrane separation tank (E2). , A transfer pipe (A2) which is provided with a mechanical pump (P2) for transferring treated water and transfers the treated water from a water treatment tank different from the membrane separation tank (E2) to the membrane separation tank (E2)
An air supply device (3) for continuously supplying air bubbles to the transfer pipe (A2), which is a septic tank continuously connected to the mechanical pump (P2).
A septic tank equipped with. 4. A water treatment tank comprising a plurality of water treatment tanks, wherein at least one of the water treatment tanks is composed of a membrane separation tank (E2), and the water treatment tank is different from the membrane separation tank (E2). An air lift pump (Pa) for transferring treated water is provided, and a transfer pipe (A) for transferring the treated water from a water treatment tank different from the membrane separation tank (E2) to the membrane separation tank (E2).
A septic tank in which 2) is connected to the air lift pump, and an air supply device (3) capable of supplying bubbles to the transfer pipe (A2).
A septic tank equipped with. 5. The septic tank according to claim 4, wherein the air lift pump (Pa) is provided with an air supply device (3) capable of supplying fine air bubbles smaller than air lift air bubbles. 6. The membrane separation tank (E) is attached to the transfer pipe (A2).
A horizontal pipe section (2) is provided between the water treatment tank different from 2) and the membrane separation tank (E2), and the horizontal pipe section (2) is provided.
The septic tank according to any one of claims 3 to 5, wherein the air supply device (3) is provided in the.