JPH1110186A - Septic tank - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technology for suppressing stagnation of treatment water by improving flow of the treatment water in a septic tank effectively. SOLUTION: A membrane separation tank E2 containing an active sludge and provided internally with a membrane separation device M having a filter membrane is provided and an aeration device D for feeding air bubbles to the membrane separation device M is provided below the membrane separation device M and a plate-shaped body having holes communicating with a front face and a rear face each other floating in such a manner as to cover the membrane separation device M is provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention comprises a membrane separation tank containing an activated sludge and a membrane separation device having a filtration membrane, and a lower portion of the membrane separation device is provided below the membrane separation device. The present invention relates to a septic tank provided with an air diffuser for supplying air bubbles.

[0002]

2. Description of the Related Art Heretofore, a septic tank of this kind has been provided in which the above-mentioned membrane separation device is simply immersed and arranged in a membrane separation tank. Further, there is a problem that the flow of the water to be treated, which is caused by the rise of the bubbles from the air diffuser, is not easily converted in the horizontal direction on the upper side of the membrane separation device, and the flow tends to be delayed. When the flow of the water to be treated is delayed, the flow of the raised water to be treated is slowed down, and the water flow in contact with the filtration membrane of the membrane separation device is delayed.Therefore, according to the solid-liquid separation of the water to be treated by the filtration membrane, As the concentration of sludge in the water to be treated increases, sludge of high concentration stays in the vicinity of the filtration membrane, which may cause a problem that dirt easily adheres to the filtration membrane. Normally, the environment is set such that such a problem does not occur, and the operation of the air diffuser is controlled. A purification tank has been proposed in which a treated water guide plate for guiding treated water to the side is immersed and disposed in the treated water and provided above the membrane separation device (FIG. 4).
reference).

[0003]

However, according to the above-mentioned conventional septic tank, even if the water to be treated is guided to the side by the water guide plate, bubbles from the air diffuser are not treated. It was confirmed that the power to rise in the water was not sufficiently converted into the flow of the water to be treated, and it was pointed out that the energy efficiency for improving the flow of the water to be treated was low. Therefore, there has been a demand for further improvement of the technology for preventing stagnation of the water to be treated.

Accordingly, it is an object of the present invention to provide a technique for efficiently improving the flow of water to be treated in a septic tank and suppressing the accumulation of the water to be treated in view of the above situation.

[0005]

The feature of the present invention for achieving this object is to accommodate activated sludge and
A membrane separation tank containing a membrane separation device having a filtration membrane is provided, and a diffuser for supplying air bubbles to the membrane separation device is provided below the membrane separation device, and an air diffusion device is provided above the membrane separation device. In addition, there is a hole communicating with the front and back, and a plate-like body that floats so as to cover the membrane separation device is provided. The operation and effect are as follows.

[Effects] The present inventors have pointed out that the above-mentioned conventional problem is caused simply by the interaction between the flows of the water to be treated when the upward flow of the water to be treated is converted in the horizontal direction. In addition to the problem described above, part of the rising energy of the bubbles and the water to be treated is consumed by the fluctuation of the surface of the water to be treated in the membrane separation tank, and is converted into a circulating flow of the water to be treated. Not found. In other words, even if a water guide plate to be treated as described in the related art is provided, as long as the guide plate is immersed and disposed in the membrane separation tank, the bubbles are generated by the water guide plate. After passing through the space from bottom to top, there is a situation where the treated water is guided in the upward direction until the flow collides with the water surface, and energy is consumed to make the water surface rippling is there. Further, when the water surface is wavy, the water flow is disturbed, and the flow of the water to be treated in the vicinity of the water surface may be obstructed, so that it is more difficult to set the flow of the water to be treated as expected. . Therefore, if a plate-like body that floats over the membrane separation device is provided, the flow of the rising bubbles forms the flow of the water to be treated and collides with the plate-like body. At this time, the flow of the water to be treated is converted in the horizontal direction by the plate-like body. In addition, since the plate-like body floats on the water surface, the water surface is prevented from waving, and turbulence is prevented, so that the flow of the water to be treated is hardly hindered. Here, as the water to be treated flows in the lateral direction along the plate-like body, the bubbles also move horizontally along the plate-like body. Since the air bubbles are provided, the air bubbles can escape from the holes in the plate-shaped body in the thickness direction, and can be prevented from being concentrated on the peripheral portion of the plate-shaped body and being released to the atmosphere. The water surface can be prevented from waving even on the peripheral side of the body, which helps to form a smooth flow of the water to be treated. Therefore, the flow of the water to be treated that has risen becomes slow, and the water flow that comes into contact with the filtration membrane of the membrane separation device stagnates. As a result, high-concentration sludge stays in the vicinity of the filtration membrane, thereby preventing the problem that dirt is likely to adhere to the filtration membrane, and lowering the water to be treated on the peripheral side of the membrane separation device. The flow velocity of the stream can also be improved, the circulation of the water to be treated as a whole in the membrane separation tank can be improved, and the treatment efficiency of the water to be treated can be improved. Adhesion can be reduced, and the membrane separation device can have a long life, and the maintenance labor of the entire septic tank can be reduced. In addition, since the bubbles reach the water surface through the holes, they do not suddenly pop, and conventionally, the droplets due to the popped bubbles adhere to the inner surface of the septic tank, grow, and become a lump,
It was feared that it would fall as a solid substance in the septic tank and give various adverse effects to the membrane separation tank.However, it also contributed to the reduction of the splash scattered on the inner surface of the septic tank. The matter accumulates at the bottom of the membrane separation tank and impedes the flow of the water to be treated, or the solid matter is interposed and held between the filtration membranes of the separation device wound up, damaging or clogging the filtration membrane. It is also useful for preventing such inconveniences. Further, since the plate-like body is floating in the membrane separation tank, the structure can be maintained even if the water level of the membrane separation tank changes.

[0007]

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 provided with mirror sections X1 and X2 at both ends of an almost oval cylindrical septic tank main body X in a longitudinal front view to form a sealed space therein, The water treatment space is divided by providing a plurality of partition plates that can be formed in a watertight manner from the upstream side,
A flow control tank N, a denitrification tank E1, a membrane separation tank E2, and a discharge pump tank T are sequentially formed from the upstream side.
Is provided. Further, a manhole H used for maintenance and the like is provided at an upper portion of each of the tanks.

The flow rate adjusting tank N receives the raw water to be treated flowing into the septic tank from an inlet I provided in one mirror portion X1 of the septic tank body X, and removes impurities in the treated water. By anaerobic bacteria growing inside while removing sediment,
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. In addition, relatively large impurities among the water to be treated flow into the flow rate adjusting tank N in a state where the impurities are separated into solid and liquid by the filtration screen F. Thereby, it is configured to be crushed and fragmented and flow into the flow rate adjusting tank N.

The denitrification tank E1 is connected to the first pump P1 by connecting an inflow pipe A1 into the water treatment chamber adjacent to the flow rate control tank N, through which water to be treated from the flow rate control tank N flows. To form an inflow passage 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 P3 for stirring and circulating the water to be treated in the tank is provided to mix the water to be treated in the tank and mix the water to be treated with a high BOD load with the nitrified water to be treated. In addition, it is configured to perform advanced denitrification processing.

[0010] The membrane separation tank E2 is provided with the inflow passage in a partition partitioning the denitrification tank E1, and the treatment water excessively flowing from the denitrification tank E1 is supplied to the denitrification tank E1. A return port A4 for returning is provided to form a return path for the water to be treated. And, in the membrane separation tank E2,
A membrane separation device M is installed.

As shown in FIGS. 1 and 2, the membrane separation device M
Is provided with a filtration membrane plate holding frame M2 for aligning and holding a large number of filtration membrane plates M1, a leg M3 for supporting the filtration membrane plate holding frame M2 is provided at a lower portion, and the filtration membrane between the legs M3. Board M
1 to prevent excessive adhesion of sludge and the like to the membrane surface and generate a circulating flow for forming an ascending flow of the water to be treated in the membrane separation tank E2. An air diffuser D which constitutes a water flow forming device for supplying oxygen to the air is internally provided. Further, an intake pipe M4 is connected to the filtration membrane plate M1 of the membrane separation device M, and the intake pipe M
A water collecting pipe M5 for connecting the filtered water from No. 4 to the outside of the membrane separation tank E2 and leading it to the outside is connected to a discharge pump tank T adjacent to the membrane separation tank E2 below the water surface of the membrane separation tank E2. Connected.

As shown in FIG. 2, a plate-like float F is disposed above the filtration membrane plate holding frame M2 in the membrane separation tank E2.
Is floated so as to be able to maintain a substantially constant posture while covering the upper part of the membrane separation device M. As shown in FIG. 3, the float F is formed by waterproofing a lightweight resin plate-like body F1, providing a large number of through-holes F2, and attaching and fixing to a frame F3 also serving as a weight. is there. The frame body F3 is also provided with a large number of through holes F4, and a hollow portion F5 is provided between the frame body F3 and the resin plate-like body F1 to supply air bubbles supplied from below. Is formed so as to be gently released to the upper side. Thereby, the float F is configured to be able to convert the flow of the water to be treated on the upper side of the membrane separation device M even if the water level fluctuates.

According to such a configuration, the flow of the water to be treated is as shown in FIG. 2, and the water to be treated can be prevented from rapidly stalling on the water surface. It has been found that the flow velocity of the downward flow of the water to be treated outside the membrane separation device M can be set faster than the flow (see FIG. 4).

The filtered water storage tank T is provided with the membrane separation tank E2.
Tank that is equipped with a disinfection device Q1 equipped with a discharge pump P4 for storing the water to be transferred to be transported, and for transferring the water to be processed almost quantitatively, and a chemical disinfectant therein.
Is configured to be able to transfer the water to be treated.

The disinfecting tank Q is provided with a disinfecting device Q1 in which a disinfectant is provided in a container formed above the filtered water storage tank T, and treats the treated water transferred from the filtered water storage tank T with the disinfectant. The treatment water disinfected by the disinfection device Q1 is configured to be freely discharged to the outside, while being provided so as to be freely contacted with the disinfectant.

In general, chemicals for disinfecting water to be treated, including chemical disinfectants, are generally referred to as disinfectants.
As 1, an ultraviolet sterilizer or the like can be used.

The through holes F2 and F2 provided in the float F
F4 is small enough not to hinder the flow of water and large enough to make it easy for bubbles to pass through, and can be set appropriately. Also, the method of positioning the float F above the membrane separation device M can be appropriately designed without being limited to the illustrated shape.

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 vertical side view of a septic tank.

FIG. 2 is a longitudinal sectional front view of a membrane separation tank of a septic tank.

FIG. 3 is a vertical sectional front view of the float.

FIG. 4 is a vertical front view of a membrane separation tank of a conventional septic tank.

[Explanation of symbols]

 M1 Filtration membrane M Membrane separation device E2 Membrane separation tank D Air diffuser F2 Hole F1 Plate

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Shinichi Furuse 2 at Takamatsu, Kosai-cho, Koga-gun, Shiga Prefecture Inside the Kubota Shiga Plant

Claims (1)

[Claims] 1. A membrane separation tank (E2) accommodating activated sludge and containing a membrane separation device (M) having a filtration membrane (M1), and said membrane separation device (M) is provided below said membrane separation device (M). A septic tank provided with an air diffuser (D) for supplying air bubbles to the membrane separator (M), and having a hole (F2) communicating between the front and back, above the membrane separator (M). And a purification tank provided with a plate-like body (F1) that floats over the membrane separation device (M).