JP2003181483A - Method for treating septic tank and the septic tank - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a treatment method for allowing operation while keeping high concentration of active sludge without causing effluence of SS to a sedimentation tank or deposition of sludge in the bottom of the sedimentation tank, and to provide a septic tank. <P>SOLUTION: An aerobic treating tank A2 is charged with a floating carrier 4, and sewage water with the carrier is made to swirl in a normal aeration state. During the process, the water is made to ascend along a water permeation membrane 2 attached to a partition plate 1 which partitions the aerobic treating tank A2 from a tank A3 for the treated water so as to peel off a biological film depositing on the water permeation membrane 2 and to prevent clogging of the water permeation membrane 2. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for treating an aerobic treatment section (biological treatment tank section) in a sewage treatment tank apparatus and a septic tank for carrying out the method.

[0002]

2. Description of the Related Art Conventionally, there are the following four types of combinations of a structure in which an aerobic treatment tank and a precipitation tank are partitioned by a partition plate. The aerobic treatment tank is an aeration tank (activated sludge), which is a normal slot type sedimentation tank. The aerobic treatment tank is a contact aeration tank and is an ordinary slot type precipitation tank. The aerobic treatment tank is a carrier fluidized bed and is an ordinary slot type sedimentation tank. The aerobic treatment tank is a biological filtration tank, which is an ordinary slot type sedimentation tank. And in any type, as shown in FIG. 5, the partition plate 11 for partitioning the aerobic treatment tank 9 and the precipitation tank 10 is installed such that the lower end surface thereof is separated from the bottom surface of the tank main body, and the partition plate 11 is underside. The aerobic treatment tank 9 and the precipitation tank 10 are communicated with each other.

Therefore, the above structure has the following problems. Fine SS flows into the settling tank and is discharged as it is. Sludge accumulates on the bottom of the settling tank, decomposes and floats, and a large amount of scum is generated. When the amount of wastewater flowing into the septic tank increases, solid-liquid separation is not sufficiently performed in the settling tank, and sludge flows out of the tank. For the above reason, the settling tank needs to have a capacity of about 30% with respect to the aerobic treatment tank, and a considerably large capacity.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the problems of the above-mentioned prior art, and its purpose is to discharge SS into the settling tank and sludge at the bottom of the settling tank. (EN) It is intended to provide a treatment method and a septic tank which can be operated while keeping the activated sludge concentration at a high level without accumulating.

[0005]

The technical means taken by the present invention to achieve the above-mentioned object is a method for treating a septic tank in which an aerobic treatment tank and a sedimentation tank are separated by a partition plate. Fill the tank with floating carrier and swirl the sewage and carrier together in a normal aeration state, while raising it along the water passage membrane attached to the partition plate that completely separates the aerobic treatment tank and the sedimentation tank. hand,
The biofilm attached to the water-permeable membrane is peeled off to prevent the water-permeable membrane from being blocked (claim 1). By this method, scum is not generated, sludge does not flow out, and solid-liquid separation is not necessary, so that the volume of the sedimentation tank (treated water tank) can be made compact.

The septic tank for carrying out the above treatment method is a partition plate that completely separates the aerobic treatment tank and the sedimentation tank in the septic tank.
A floating membrane is filled in the aerobic treatment tank, an air diffuser is arranged near the lower part of the partition plate, and a water passage membrane through which treated wastewater can pass from the aerobic treatment tank to the sedimentation tank on the partition plate. When the treated sewage passes through the water-permeable membrane, sludge in the sewage is captured, and only water and ultrafine SS pass through the water-permeable membrane. 2). That is, the partition plate for partitioning the aerobic treatment tank and the precipitation tank is brought into close contact with the bottom surface of the tank body to completely partition both tanks so that at least both tanks do not communicate with each other below the partition plate. Then, a water-permeable membrane is provided at a position above the middle of the partition plate in the height direction.
With the above configuration, the floating carrier filled in the aerobic treatment tank hits the water-permeable membrane on the surface of the water-permeable membrane by the upward flow of bubbles emitted from the air diffuser along the partition plate. The adhered biofilm can be stripped off efficiently and a stable processing function can be maintained for a long period of time.

Further, the water-permeable membrane provided on the partition plate has a hole diameter of 0.02 to 0.07 mm and is made of a material which is not damaged even if the floating carrier filled in the aerobic treatment tank hits (claim 3). ). By setting the hole diameter of the water-permeable membrane within the above range, it is possible to prevent the passage of ordinary sludge or the like (flock of biological membrane, etc.).
Examples of the material of the film include non-woven fabric such as polyester, stainless wire or plain weave of nylon. Further, the water-permeable membrane may be detachable from the partition plate (claim 4). The above water-permeable membrane is adhered with oil or the like during long-term use, resulting in insufficient scraping of fine SS due to contact with the upward flow of air bubbles discharged from the air diffusing tube or floating carrier, Although the water-permeable membrane may be blocked, the water-permeable membrane portion can be removed and cleaned by the above-described configuration, and the water-permeable membrane can be replaced with a new one, so that clogging can be eliminated and maintenance can be easily performed.

Further, it is preferable that the partition plate is attached so as to be inclined toward the aerobic treatment tank side, and the attachment angle thereof is 15 to 45 degrees (claim 5). As a result, the bubbles released from the air diffusing pipe ascend while traveling along the water-permeable membrane, and as a result, vibration is imparted to the water-permeable membrane. As a result, the microbial membrane attached to the membrane surface is peeled off and the water-permeable membrane is prevented from being blocked.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an example of a septic tank according to the present invention. In the septic tank A, a pretreatment tank A1 is sectioned and formed on the side of an inlet a of sewage or the like, and an aerobic gas is provided between the pretreatment tank A1 and the outlet b. A treatment tank A2 is disposed, and a partition plate 1 that completely separates the outflow port b into two chambers is installed in the aerobic treatment tank A2 to form a treated water tank A3. The floating carrier 4 is filled inside.

The pretreatment tank A1 may be any of a precipitation separation layer, an anaerobic filter bed tank and the like. In any case, the wastewater from which the oil content and the solid matter have been removed in the pretreatment tank A1 is configured to flow into the aerobic treatment tank A2.

The partition plate 1 installed in the aerobic treatment tank A2 is
The lower end surface is placed in close contact with the bottom surface of the tank to completely partition the aerobic treatment tank A2 and the treated water tank A3 so that both tanks do not communicate with each other under the partition plate. And this partition board 1
Between the middle position and the upper end in the height direction of the partition plate 1
An opening 5 is opened in the center portion in the width direction of, and the water-permeable membrane 2 is detachably provided in the opening 5. Further, the partition plate 1 is attached such that its upper end side is inclined to the aerobic treatment tank A2 side. The angle of inclination of the partition plate 1 is 1
About 5 to 45 degrees is preferable. An air diffuser 3 is arranged along the partition plate 1 on the aerobic treatment tank A2 side.
Thereby, the bubbles released from the air diffuser 3 rise along the partition plate 1 and impart vibration to the water-permeable membrane 2,
As a result, it functions to peel off the microbial membrane attached to the surface of the water-permeable membrane 2.

The water-permeable membrane 2 has a hole diameter of 0.02 mm to
The membrane has a thickness of about 0.07 mm and cannot pass ordinary sludge and the like (such as flocs of biofilm), and its strength is such that it will not be damaged even when the floating carrier comes into contact with it. Examples of the material for the water-permeable membrane 2 include non-woven fabric such as polyester, stainless steel wire, plain weave such as nylon, and the membrane 2 is stretched around the frame 6. still,
The frame body 6 having the water-permeable membrane 2 stretched is the opening 5 of the partition plate 1.
It is slidably mounted on the frame 7 mounted along the edge of the.

Floating carrier 4 filled in the aerobic treatment tank A2
Is a granular material having a specific gravity of about 1 and a size of about 5 mm to 20 mm, which can swirl with a water flow, and may have a large specific surface area. In addition, the filling amount is the aerobic treatment tank A
It is about 30 to 50% with respect to the capacity of 2.

Next, the processing operation will be described. First, sewage from which oil and solids have been removed in the pretreatment tank A1 flows into the aerobic treatment tank A2. In this aerobic treatment tank A2, organic matter in wastewater is efficiently decomposed and removed by the high concentration of activated sludge and the microorganisms in the floating carrier. Microorganisms grown in organic matter in wastewater have MLSS concentrations of 10,000 m
It is about g / l. Further, after a long time, the MLSS concentration may become higher than that, but in that case, the sludge in the aerobic treatment tank A2 is extracted.

On the other hand, the sewage flowing into the aerobic treatment tank A2 is
When the surface of the water passage membrane 2 attached to the upper part of the partition plate 1 is contacted, sludge (biological flocs) in the wastewater is captured, and only water and ultrafine SS pass through the water passage membrane 2. .
An air diffuser 3 is installed below the water-permeable membrane 2, and air bubbles are generated and released as an upward flow, so that the water-permeable membrane 2 is vibrated along with the upward flow, The sludge captured by the water-permeable membrane 2 is forcibly separated by the vibration. In this way, the MLSS concentration in the aerobic treatment tank A2 gradually increases.

Further, when the wastewater flowing into the aerobic treatment tank A2 contains a large amount of oil or when the water passage membrane 2 is clogged due to some other cause, the aeration is stopped. After leaving the aerobic treatment tank A2 stationary and confirming that solid-liquid separation has occurred and sludge has accumulated on the bottom of the aerobic treatment tank A2, the supernatant water is drawn out until the entire water-permeable membrane 2 is visible, After that, the water-permeable membrane 2 is pulled out, washed sufficiently with tap water, and then attached to the partition plate 1. Incidentally, if it seems impossible to repair, replace the water-permeable membrane 2 of the frame 6 with a new membrane,
Exchange.

The treated water that has passed through the water-permeable membrane 2 as described above is temporarily stored in the treated water tank A3, sterilized by the disinfection device 8, and then discharged. When nitrogen removal is also performed by this apparatus, an air lift pump (not shown) is installed in the treated water tank A3 to constantly circulate the treated water in an amount of 3 to 4 times the inflow water amount to the pretreatment tank A1. Thereby, the nitrified nitrate nitrogen in the treated water is denitrified by the denitrifying bacteria in the pretreatment tank A1.

[0018]

According to the method for treating a septic tank of the present invention, according to the constitution of claim 1, the operation can be performed while keeping the concentration of activated sludge in the aerobic treatment tank high, scum is not generated, and sludge can be discharged. It can be prevented. Further, according to the configuration of claim 2,
The above-described processing method can be effectively executed, and the above-mentioned conventional problems can be solved. Further, with the structure according to the third aspect, passage of ordinary sludge or the like (flock or the like of biofilm) can be prevented. Further, according to the structure of claim 4, even if the water-permeable membrane is closed, it can be easily washed and replaced by removing the member to which the membrane is attached from the partition plate. Further, according to the configuration of claim 5, the bubbles released from the air diffusing pipe ascend while being transmitted through the water-permeable membrane, whereby the membrane is vibrated, and the microbial membrane attached to the water-permeable membrane is efficiently separated. Therefore, the stable function of the water-permeable membrane can be maintained for a long period of time.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a septic tank showing an example of an embodiment of the present invention.

FIG. 2 is a vertical sectional side view of the same.

FIG. 3 is a cross-sectional view showing a state in which a water-permeable membrane is removed from a partition plate.

FIG. 4 is an enlarged perspective view showing a water-permeable membrane portion.

FIG. 5 is a cross-sectional view showing a conventional structure.

[Explanation of symbols]

A ... Septic tank A1 ... Pretreatment tank A2 ... Aerobic treatment tank A3 ... Treated water tank 1 ... Partition plate 2 ... Water-permeable membrane 3 ... Air diffuser 4 ... Floating carrier

Continued front page    F-term (reference) 4D003 AA12 AB04 BA01 BA02 CA02                       CA04 DA11 DA18 DA19 DA21                       EA01 EA19 FA01                 4D027 AA02 AA12 AA14 AB06 AB12                       AB14

Claims (5)

[Claims] 1. A method for treating a septic tank in which an aerobic treatment tank and a sedimentation tank are separated by a partition plate, wherein the aerobic treatment tank is filled with a floating carrier, and the waste water and the carrier are swirled together in a normal aeration state. ,
At that time, it is raised along the water passage membrane attached to the partition plate that separates the aerobic treatment tank and the sedimentation tank, and the biological membrane adhering to the water passage membrane is peeled off to prevent clogging of the water passage membrane. A method for treating a septic tank, which comprises: 2. An aerobic treatment tank and a sedimentation tank in a septic tank are completely partitioned by a partition plate, the aerobic treatment tank is filled with a floating carrier, and an air diffuser is arranged near the lower part of the partition plate. The partition plate is provided with a water passage membrane that allows treated wastewater to pass from the aerobic treatment tank to the sedimentation tank.When the treated wastewater passes through the water passage membrane, sludge in the wastewater is trapped, and water and ultrafine particles are trapped. SS
A septic tank characterized in that only the water is passed through the water-permeable membrane. 3. The water-permeable membrane provided on the partition plate has a hole diameter of 0.02 to 0.07 mm and is a material that is not damaged even if the floating carrier filled in the aerobic treatment tank hits it.
The described septic tank. 4. The septic tank according to claim 2 or 3, wherein the water-permeable membrane is detachable from the partition plate. 5. The partition plate according to claim 2, wherein the partition plate is mounted so as to be inclined toward the aerobic treatment tank, and the mounting angle is 15 degrees to 45 degrees. Septic tank.