JP2002001369A - Sewage septic tank with bioreactor charged with precipitating carrier - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sewage septic tank for biologically cleaning sewage or waste water such as human excrement or miscellaneous drainage and a method of cleaning sewage. SOLUTION: In the sewage septic tank, an anaerobic treating tank having a flow control function and/or a flow control tank, the biological reaction tank 4 and a sterilization tank 5 are arranged in this order from the upstream side and the precipitating carrier capable of fluidizing by aeration is filled in the biological reaction tank 4. A diffusion member 7 and a communicated port 9 to a next tank are provided and a lower end of a discharge pipe 10 for taking out a tank inside liquid is arranged in the lower part of the biological reaction tank. The discharge pipe 10 can be connected to a transporting pipe 11. A single fluidized bed is formed during the aeration from the diffusion member 7 and a single fixed bed is formed when the aeration is stopped. The sewage is anaerobically treated in the anaerobic treating tank or the flow control tank and successively, biologically degraded aerobically at the time of being aerated in the biological reaction tank and the suspended substance is captured, denitrificated when the aeration is stopped to stably obtain excellent treated water.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a sewage purification tank in which a biological reaction tank is filled with a sedimentable carrier. More specifically, the present invention relates to a sewage purification tank for biologically purifying sewage or wastewater such as night soil and gray water, and a method for purifying sewage.

[0002]

2. Description of the Related Art Various types of sewage treatment tanks have been known. An example of a commonly used sewage purification tank is shown in FIG. 3 (JP-A-9-248584). In this sewage purification tank, the aerobic filter bed tank is divided into two filter bed chambers: an upper R zone (biological reaction layer) filled with granular carriers and a lower F zone (filter layer) also packed with granular carriers. At the same time, a washing drainage pipe is provided under the F zone, and diffuses from below the R zone during biological reactions (does not diffuse from below the F zone). The air is diffused, and at that time, the F zone (filtration layer) washing drainage is returned to the anaerobic filter bed tank (first chamber) while being pulled out from the washing drainage pipe via an air lift pump. In this sewage purification tank, a tank (that is, a treated water tank) for storing water for washing the F zone (filtration layer) is substantially unnecessary.

There is also known a sewage purifying tank having a so-called flow rate adjusting function in an anaerobic filter tank (first and second chambers) in front of an aerobic filter tank (JP-A-6-28548).
No. 4). These sewage treatment tanks are characterized in that sewage can be treated more efficiently and stably than conventional sewage treatment tanks, and the entire tank can be reduced in size.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to develop these sewage treatment tanks and further improve their performance.

[0005]

In order to achieve the above object, the sewage purifying tank of the present invention has the following configuration. That is, the sewage purification tank of the present invention is a sewage purification tank in which an anaerobic treatment tank and / or a flow rate adjustment tank having a flow rate adjustment function, a biological reaction tank 4, and a disinfection tank 5 are sequentially arranged from the upstream side. The biological reaction tank 4 is a sewage purification tank filled with a sedimentable carrier that can flow by aeration.

Here, in the above-mentioned sewage purification tank, an air diffusion member 7 and (to the next tank) are usually provided below the biological reaction tank 4.
A communication port 9 is provided.

In the above-mentioned sewage treatment tank, usually,
A fluidized bed (usually, a single bed) is formed in the biological reaction tank 4 when aeration is performed from the diffusing member 7, and a fixed bed (normally, a single bed) is formed in the biological reaction tank 4 when aeration is not performed from the diffusing member 7. Is done.

In the sewage purification tank, preferably, a lower end of a discharge pipe 10 for extracting a liquid in the tank is disposed below the biological reaction tank 4, and the discharge pipe 10 is connected to a transfer pump 11. .

In the sewage purification tank, the liquid drawn by the transfer pump 11 is preferably returned to an anaerobic treatment tank or a flow rate adjustment tank which is a tank upstream of the biological reaction tank 4.

[0010] The present invention also relates to a method for purifying sewage. That is, the method includes, from the upstream side, an anaerobic treatment tank having a flow rate adjustment function and / or a flow rate adjustment tank, a biological reaction tank 4, and a sewage purification tank in which a disinfection tank 5 is arranged in order. In the flow control tank, the supplied sewage (raw water) is mainly subjected to anaerobic treatment or stored, and in the biological reaction tank 4, (a) a diffuser member while stopping the inflow of the liquid from the front tank. Aeration reaction in which aeration is performed while forming a fluidized bed in the biological reaction tank 4 by aeration from (7), and (b) the liquid is introduced from the previous tank while the aeration member 7 enters the biological reaction tank 4 without aeration. And a non-aeration reaction in which treatment is performed while forming a fixed bed is performed alternately (that is, intermittent aeration treatment is performed). In the disinfecting tank 5, treated water is disinfected and then discharged. It is a method of purifying sewage.

Here, during the above-mentioned non-aeration reaction, the liquid flowing into the biological reaction tank 4 flows downward and passes through the fixed bed, and the passed liquid flows from the communication port 9 provided at the lower part of the tank to the disinfection tank 5. It is preferable to guide At this time, it is preferable that the liquid that has passed through the fixed bed is returned from the lower part of the biological reaction tank 4 to the anaerobic treatment tank or the flow control tank.

Further, while the liquid flows into the biological reaction tank 4 from a tank (ie, an anaerobic treatment tank or a flow rate adjustment tank) before the biological reaction tank 4, the liquid in the tank is withdrawn from the lower part of the biological reaction tank 4. In this case, a part of the extracted liquid in the tank is
It is preferable to return to an earlier tank (that is, an anaerobic treatment tank or a flow rate adjustment tank).

[0013]

[Function] When the aeration member 7 is aerated into the biological reaction tank 4,
The sedimentable carrier filled in the tank flows by the stirring flow,
A fluidized bed is formed and the wastewater (liquor) is aerobically biotreated (oxidation of organic matter and nitrification of ammonia). At this time, no sewage (liquid) flows into the biological reaction tank 4. When the aeration member 7 does not aerate the inside of the biological reaction tank 4, that is, at the time of non-aeration, the sedimentable carrier sinks and a fixed bed is formed in the tank. Then, the liquid flowing into the biological reaction tank 4 from a tank (anaerobic treatment tank having a flow rate adjusting function or a flow rate adjusting tank) upstream of the biological reaction tank 4 pushes down the processing liquid purified by the biological reaction tank 4. While flowing downward, the suspended solids (SS) contained therein are captured by the fixed bed (settling carrier). The liquid that has passed through the fixed bed exits from the communication port 9 and is guided to the disinfection tank 5. As described above, since the inflow of sewage (liquid) is not performed during the aeration reaction but is performed only during the non-aeration reaction, the leakage of SS is small. In addition, at the time of the non-aeration reaction,
Since the inside becomes anaerobic, the denitrification reaction proceeds.

[0014]

Embodiments of the present invention will be described below more specifically with reference to the accompanying drawings. FIG. 1 is a schematic view of the configuration of a sewage treatment tank according to an example of the present invention when aerated, and FIG. 2 shows the corresponding non-aerated state. Arrows in the figure indicate flows of air and liquid, respectively. 1 and 2, the inflow of sewage flowing into the sewage purification tank from outside the system is omitted.

The biological reaction tank 4 is filled with a "sedimentable carrier" which sediments when not aerated (non-stirred) and can flow during aeration (diffused) and stirred. Therefore, at the time of aeration and stirring, the carrier flows in the biological reaction tank 4 to form a fluidized bed,
At the time of non-aeration (aeration stop), the carrier sediments and a fixed bed is formed. Here, as the "precipitable carrier" used,
In a small shape, various shapes such as a mesh-like cylindrical shape, a skeleton-like spherical shape, a cylindrical shape, a tube shape, and a fiber entangled shape, a filter medium having a high SS trapping ability is preferable. (A communicating cell or a closed cell, preferably a communicating cell).

These sedimentable carriers are respectively provided on the upper and lower parts of the biological reaction tank 4 so as not to flow out of the biological reaction tank 4.
A water-permeable member 8 that allows the liquid to pass through but does not allow the carrier to pass through is disposed.

An air diffusion member 7 such as an air diffusion tube is disposed below the biological reaction tank 4. Aeration is performed from the air diffusing member 7 during aeration, and is not performed during non-aeration. Aeration and non-aeration can be alternately and periodically performed by using a timer or the like.

At the lower part of the biological reaction tank 4, a lower end of a discharge pipe 10 for extracting a liquid in the biological reaction tank is arranged, and the other end of the discharge pipe 10 is connected via a transfer pump (air lift pump) 11. To return to the anaerobic filter bed tank (first chamber) 2. The return destination of the liquid is the anaerobic filter bed tank (second chamber) 3
It may be.

The anaerobic filter bed tank (first chamber) 2 and the anaerobic filter bed tank (second chamber) 3 also serve as a flow control tank. It is installed in the advection tube to the reaction tank 4. The sewage that has passed through the anaerobic filter bed tank (second chamber) 3 is pumped up by an air lift pump, separated, weighed, and sent to the biological reaction tank 4. Flow control pump 1
2 may be a general-purpose water pump instead of the air lift pump.

The anaerobic filter bed tank (first chamber) 2 and the anaerobic filter bed tank (second chamber) 3 are also filled with a filler to form a filter bed. The filler used is a mesh-like cylinder, a skeleton-like sphere, a plate-like luffa-like, a small cylinder, a corrugated plate, or the like. In addition, an anaerobic treatment tank without a filter bed may be used instead of the anaerobic filter bed tank (first or second chamber).

Next, the flow of sewage will be described with reference to FIGS. The sewage is first supplied from the inlet 1 to the anaerobic filter bed tank (first chamber).
Enter 2. The anaerobic filter bed tank (first chamber) 2 and the subsequent anaerobic filter bed tank (second chamber) 3 undergo anaerobic decomposition together with removal of contaminants, and are sent to the biological reaction tank 4 by the flow control pump 12. The flow rate adjusting pump 12 is linked with a control device 14 that controls a blower (blower) 13, and operates only during non-aeration of the biological reaction tank 4 to feed the liquid.

In the biological reaction tank 4 during non-aeration, the sedimentable carrier filled therein is settled and is in a stationary state, so that a fixed bed is formed. The sewage (liquid) sent by the flow control pump 12 pushes the aerobic-treated liquid downward at the time of aeration, and the pushed liquid passes through the fixed bed in a downward flow, and the SS in the fixed bed causes SS to flow. While being trapped and removed, it exits from the communication port 9 and is guided to the disinfection tank 5. In addition, at the time of non-aeration, since the inside of the biological reaction tank 4 is in an anaerobic state, a denitrification reaction occurs, and nitrogen is also removed.

The amount of sewage sent by the flow control pump 12 is preferably equal to or less than the capacity of the biological reaction tank 4. If the liquid is sent beyond the capacity of the biological reaction tank 4, the SS can be removed, but the SS flows out without aerobic treatment.

At the time of aeration, air (oxygen-containing gas) is discharged from the air diffusing member 7 in the biological reaction tank, and microorganisms attached to the carrier mainly promote oxidation and decomposition of organic substances and nitrification of ammonia.

The SS captured on the carrier (when not aerated) is:
At the time of aeration, it is released from the carrier and settles at the bottom of the biological reaction tank 4. The settled SS is pulled out from a lower end of a discharge pipe 10 arranged at a lower part of the biological reaction tank 4 via a transfer pump (air lift pump) 11. The liquid containing SS is returned to the anaerobic filter bed tank (first chamber) 2. The timing of withdrawing the liquid is not particularly limited, but is preferably performed during non-aeration. This is because SS is likely to settle during non-aeration. In this case, the amount of the liquid to be withdrawn is smaller than the amount flowing into the biological reaction tank 4.

At the time of non-aeration, the treated water extruded from the communication port 9 after the biological treatment passes through the advection pipe 15, is sterilized in the disinfection tank 5, and is discharged from the discharge port 6.

In the examples of FIGS. 1 and 2, the anaerobic treatment tank and / or the flow control tank having the flow control function are the anaerobic filter tank (first chamber) and the anaerobic filter tank (the first chamber) having the flow control function. Although the example of the second chamber has been described, various other embodiments are possible. For example, an example in which the first tank is an anaerobic filter bed tank and the second tank is a flow rate control chamber provided with a diffusing member (with or without a filter bed in this case), This is an example of reversing, an example of disposing only one of the anaerobic treatment tank and the flow control tank, and the like. When the air diffusion member is provided in the flow control chamber, aerobic treatment can be added in the flow control chamber.

[0028]

According to the sewage purification tank of the present invention, or according to the sewage purification method of the present invention, sewage is anaerobically treated in an anaerobic treatment tank or a flow control tank, and subsequently, when aerated in a biological reaction tank. Biodegraded aerobically, SS is captured and denitrified when not aerated, and good treated water can be obtained stably.

Further, all of the carriers filled in the biological reaction tank are effectively used for aerobic treatment, trapping of SS, denitrification treatment, etc. using the entire tank. , The entire sewage treatment tank) can be downsized.

[Brief description of the drawings]

FIG. 1 is a schematic view of a configuration of a sewage treatment tank according to an example of the present invention, which is at the time of aeration. Arrows indicate air and liquid flows.

FIG. 2 is a schematic diagram of a configuration of a sewage purification tank corresponding to FIG. 1 without aeration. Arrows indicate air and liquid flows.

FIG. 3 is a schematic diagram of a configuration of a conventional sewage purification tank.

[Explanation of symbols]

1: Inlet 2: Anaerobic filter bed tank (first chamber) 3: Anaerobic filter bed tank (second chamber) 4: Biological reaction tank 5: Disinfection tank 6: Discharge port 7: Aeration member (aeration tube) 8: Water-permeable member 9: Communication port 10: Discharge pipe 11: Transfer pump (air lift pump) 12: Flow control pump 13: Blower (blower) 14: Control device 15: Transfer pipe

Claims (6)

[Claims] An anaerobic treatment tank having a flow control function and / or a flow control tank, a biological reaction tank, and a disinfection tank are arranged in this order from the upstream side. The biological reaction tank is aerated. A sewage purification tank filled with a sedimentable carrier that can flow through. 2. The sewage purification tank according to claim 1, wherein a diffusion member and a communication port are provided at a lower portion of the biological reaction tank. 3. The sewage treatment tank according to claim 1, wherein a fluidized bed is formed in the biological reaction tank when aeration is performed from the diffuser member, and a fixed bed is formed in the biological reaction tank when aeration is not performed from the diffuser member. 4. The sewage purification tank according to claim 1, wherein a lower end of a discharge pipe for extracting a liquid in the tank is arranged at a lower part of the biological reaction tank, and the discharge pipe is connected to a transfer pump. 5. The sewage treatment tank according to claim 4, wherein the liquid drawn by the transfer pump is returned to the anaerobic treatment tank and / or the flow control tank. 6. An anaerobic treatment tank having a flow control function and / or a sewage purification tank comprising a flow control tank, a biological reaction tank, and a disinfection tank arranged in order from the upstream side, wherein the anaerobic treatment tank and / or the flow rate In the adjustment tank, the supplied wastewater is anaerobically treated or stored, and in the biological reaction tank,
(A) Aeration reaction in which the flow of liquid from the front tank is stopped and aeration is performed while forming a fluidized bed in the biological reaction tank by aeration from the aeration member, and (b) dispersion while flowing the liquid from the front tank. The non-aeration reaction of treating while forming a fixed bed in the biological reaction tank without aeration from the gaseous member is performed alternately, and in the disinfection tank, the treated water is disinfected and then discharged, Purification method.