JP2000325977A - Septic tank and operation thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a septic tank making it easy to certainly lower the load in an aerobic treatment tank after the washing of the carrier in the aerabic treatment tank. SOLUTION: A septic tank is equipped with an aeration treatment tank E1 provided with a washing device D1 housing and holding a carrier C1 formed so as to be flowable along with water to be treated in such a state that microorganisms are supported and washing the carrier C1, pretreatment tanks N1, N2 for pretreating water to be treated allowed to flow in the aerabic treatment tank E1 on the upstream side of the aerobic treatment tank E1, a return pump P2 for transferring washing sludge generated by washing the carrier C1 to the tank on the upstream side of the aerobic treatment tank E1, a transfer pipe P for transferring water to be treated from the pretreatment tanks N1, N2 to the aerobic treatment tank E1 and a control device capable of changing over the operation and stop of the transfer pump corresponding to the washing operation period of the carrier C1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention provides a carrier washing device for accommodating and holding a carrier which is formed to be capable of flowing along with water to be treated in a state in which microorganisms are supported, and for washing the carrier. The carrier fluidized tank, provided with at least one pretreatment tank for pretreating the water to be treated to flow into the carrier fluidized vessel on the upstream side of the carrier fluidized vessel, and washing sludge generated by washing the carrier, Septic tank provided with a return pump for transferring to the tank on the upstream side of the carrier fluidizing tank, or
A biological filtration tank which contains a carrier for supporting microorganisms, and holds the water to be treated so as to be capable of being filtered; and a biological filtration tank provided with a carrier washing device for washing the carrier. Tank having at least one pretreatment tank for pretreating the carrier on the upstream side of the biological filtration tank, and provided with a return pump for transferring the washing sludge generated by washing the carrier to a tank upstream of the carrier fluidizing tank. And further relates to a method of operating the septic tank.

[0002]

2. Description of the Related Art Heretofore, as this type of purification tank, there has been proposed a type in which water to be treated is transferred from the pretreatment tank to the carrier fluidization tank or the biological filtration tank by overflow. In such a case, a pretreatment tank is provided adjacent to the carrier fluidizing tank or the biological filtration tank (hereinafter, both are abbreviated as an aerobic treatment tank), and the aerobic treatment and the pretreatment tank are combined. The partition wall is provided with an opening through which the water to be treated can freely overflow, and the water to be treated flows from the opening to the aerobic treatment as the water level in the pretreatment tank rises. In addition, the carrier accommodated in the above-described carrier fluidized tank is configured to float and circulate in the carrier fluidized vessel, usually following the advection of the water to be treated due to aeration or the like, but is carried. When the microorganisms perform the treatment of the water to be treated, since the sludge and the like grow on the carrier, the sludge and the like attached to the surface are periodically peeled off by, for example, diffusing the carrier, The reduction of the activity of microorganisms due to such sludge is suppressed. At this time, the sludge generated by peeling is returned to a pretreatment tank capable of decomposing a sewage component having a higher load in order to perform a more complete decomposition process. Further, the carrier in the biological filtration tank and the environment in the tank after the washing are similar to the carrier flow tank, and the sludge and the like generated by separation are returned to the upstream tank.

[0003] The carrier in the carrier fluidizing tank usually has a grid-like or slit-like shape formed to allow passage of the water to be treated but not through the carrier so as not to be transferred to another adjacent tank. It is held in the tank by a member.

[0004]

However, according to such a configuration, when the separated sludge is returned to the upstream of the carrier fluidizing tank such as the pretreatment tank, the water to be treated is not returned. The water level in the pretreatment tank may rise rapidly after receiving the return of the water to be treated, because the water has to be returned with the flow. Then, a high-load component such as a solid substance floating in the pretreatment tank may flow into the carrier fluidization tank.

[0005] Then, contrary to the initial purpose of reducing the load in the carrier fluidization tank and suppressing the decrease in the activity of microorganisms due to sludge, the load may be increased, which may result in a reduction in the activity.

Accordingly, an object of the present invention is to provide a purifying tank which can more reliably reduce the load in the carrier flow tank after the carrier in the carrier flow tank has been washed, in view of the above-mentioned drawbacks. To provide technology.

[0007]

A feature of the present invention for achieving the above object is that the septic tank of the present invention stores and holds a carrier which is formed to be capable of flowing along with the water to be treated in a state where microorganisms are supported. And a carrier fluidization tank provided with a carrier washing device for washing the carrier, and at least one pretreatment tank for pretreating water to be treated flowing into the carrier fluidization vessel upstream of the carrier fluidization vessel. A return pump for transferring the washing sludge generated by washing the carrier to a tank on the upstream side of the carrier flow tank, and an advection pump for transferring water to be treated from the pretreatment tank to the carrier flow tank. The present invention is characterized in that a control device is provided for enabling the advection pump to be switched on and off in accordance with the cleaning operation timing for cleaning the carrier.

[0008] To achieve this object, the method of operating the septic tank according to the present invention is characterized in that, in the state where microorganisms are supported,
A carrier formed so as to be able to flow with the water to be treated is contained and held, and a carrier fluidizing tank provided with a carrier washing device for washing the carrier is provided. The apparatus has at least one pretreatment tank for performing pretreatment on the upstream side of the carrier fluidization tank, and a return pump for transferring the cleaning sludge generated by washing the carrier to a vessel on the upstream side of the carrier fluidization vessel is provided. Transferring the water to be treated from the pretreatment tank to the carrier fluidizing tank, and performing a water level adjustment step of bringing the upstream vessel of the carrier fluidizing tank into a low water state,
A cleaning step of cleaning the carrier in the carrier fluidizing tank is performed.

[0009] Further, a carrier for supporting microorganisms is accommodated,
The water to be treated is held so as to be capable of being filtered, and a biological filtration tank provided with a carrier washing device for washing the carrier is provided. The water to be treated to flow into the biological filtration tank is provided on the upstream side of the biological filtration tank. Even a purification tank provided with at least one pretreatment tank for performing pretreatment and provided with a return pump for transferring washing sludge generated by washing the carrier to a tank on the upstream side of the carrier fluidizing tank, Is the same as

[Effects] In other words, the water to be treated transferred to the carrier fluidizing tank is transferred from the pretreatment tank via a transfer pump. It is constantly transferred into the carrier fluidization tank without being affected by the water level. Therefore, the water level of the pretreatment tank is
It is possible to control independently regardless of the water level in the carrier fluidization tank. On the other hand, when performing the washing operation of the carrier in the carrier flowing tank, the return pump can be operated to transfer sludge and the like to a tank upstream of the carrier flowing tank such as the pretreatment tank. As the water level drops rapidly, the water level in the tank on the upstream side of the carrier flow tank rises rapidly.

At this time, an increase in the water level in the upstream tank of the carrier flow tank causes an increase in the water level in the pretreatment tank.
This is because even when the pretreatment tank is single (when the tank on the upstream side of the carrier flow tank is a pretreatment tank), when there are a plurality of pretreatment tanks (the carrier flow tank is covered). The same applies to the case where the tank for transferring the treated water is different from the tank for receiving the return water from the carrier flow tank). Therefore, according to the conventional overflow configuration, when the water level in the pretreatment tank is high, the solid may flow from the pretreatment tank to the carrier fluidization tank. However, if the water to be treated is transferred from the pretreatment tank to the carrier fluidizing tank by an advection pump, it is possible to prevent the solids from overflowing due to the rise in the water level. Therefore, before returning sludge and the like from the carrier fluidizing tank to the pretreatment tank, the water level of the pretreatment tank is sufficiently low so that the sludge and the like from the carrier fluidizing tank can be sufficiently received. If this can be done, it is possible to prevent the solid material from flowing from the pretreatment tank to the carrier fluidization tank. Therefore, a control device is provided that includes an advection pump that transfers the water to be treated from the pretreatment tank to the carrier fluidization tank, and that enables the advection pump to be operated and stopped to be switched in accordance with a cleaning operation time for cleaning the carrier. If provided, the advection pump is operated immediately before the cleaning operation time, the water level in the pretreatment tank can be lowered, and control is performed so as to receive the water to be returned from the carrier fluidization tank. be able to.

[0012] Therefore, the load in the carrier fluidized tank can be effectively and efficiently reduced, thereby contributing to stable water treatment.

[0013] In addition, as a method of operating such a purification tank, water to be treated is transferred from the pretreatment tank to the carrier fluidization tank, and the water level adjustment is performed so that the upstream vessel of the carrier fluidization vessel is at a low water level. After performing the step, by performing a washing step of washing the carrier in the carrier fluidized tank, when washing the carrier in the carrier fluidized vessel, once the water level of the pretreatment tank is low Is realized, the carrier is washed, and the sludge and the like generated by the washing can be returned to the pretreatment tank having the lowered water level. Therefore, while reliably returning sludge, it is possible to prevent inconveniences such as re-inflow of solids into the carrier fluidization tank, and to stabilize the load in the carrier fluidization vessel.

A septic tank which contains a carrier for carrying microorganisms, holds the water to be treated so that it can be filtered, and has a biological filtration tank provided with a carrier washing device for washing the carrier. It functions similarly to the case where the carrier fluidizing tank is provided.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. As shown in FIG. 1, the septic tank constituting the sewage treatment apparatus of the present invention is provided with an anaerobic filter bed first chamber N1 and a second chamber N2 in order from the upstream side, and the water to be treated flows in this order by overflow. In addition to the above, a carrier flow tank E1 and a filtration tank E2 are provided downstream of the anaerobic filter bed second chamber N2. Further, a treatment water tank T1 is formed downstream of the carrier fluidization tank E1 so that water to be treated can be transferred upward under the filtration tank E2, and a disinfection tank is provided above the treatment water tank T1. Q is provided. With such a configuration, the first chamber N1 and the second chamber N2 of the anaerobic filter tank play a role as a pretreatment tank for the carrier fluidizing tank E1. The raw water to be treated is supplied from the raw water inflow section I to the first anaerobic filter bed tank N1.
While being disintegrated while being transferred downstream in the order of the anaerobic filter bed tank second chamber N2, the carrier fluidizing tank E1, the filtration tank E2, and the treated water tank T1, and disinfecting the disinfecting tank Q provided above the treated water tank T1. After passing through, the water is discharged from the discharge port Z to the outside of the tank.

The anaerobic filter bed first chamber N1 is configured to be able to store the raw water that flows into the to-be-processed water, so that anaerobic microorganisms can be grown therein. Raw water to be treated flowing into the anaerobic filter tank first chamber N1 is stored in the anaerobic filter tank first chamber N1 and is also anaerobically decomposed to mainly separate coarse organic substances. Then, it is transferred from the lower part of the first anaerobic filter tank N1 to the lower part of the second anaerobic filter tank N2. Also, solids such as sludge that is not easily decomposed are settled below the anaerobic filter tank first chamber N1, or
It is stored as scum in the upper part of the first chamber N1 of the anaerobic filter tank.

The anaerobic filter bed second chamber N2 is provided with an anaerobic filter bed F
And an anaerobic microorganism can be fixedly maintained on the anaerobic filter bed F and grown. Further, the anaerobic filter bed tank second chamber N2 is equipped with an advection pump P composed of an air lift pump for transferring water to be treated to the carrier fluidizing tank, and has flowed into the anaerobic filter bed tank second chamber N2. The water to be treated further undergoes anaerobic treatment and is decomposed to a state with almost no solid matter, and then is sent to the carrier fluidizing tank E1 by the advection pump P.

As shown in FIG. 2, the carrier fluidizing tank E1
Holds and holds the carrier C1, which is formed to be flowable together with the water to be treated, in a state in which the microorganisms are supported,
An air diffuser D1 that allows the carrier to flow by the supply of air bubbles is provided, and an air diffuser is provided inside the air diffuser D1, and the carrier C1 is caused to flow in the carrier flow tank E1 by the supply of air bubbles from the air diffuser D1. is there. With such a configuration, the water to be treated flowing into the carrier fluidization tank E1 is purified by aerobic decomposition by aerobic microorganisms. The water to be treated that has undergone such treatment is transferred to the filtration tank E2 through the transfer wall 3 provided on the first partition W1 that partitions the carrier flow tank E1 and the adjacent filtration tank E2. The advection wall portion 3 is formed in a lattice shape or a slit shape, and is configured to prevent the advection of the carrier C1, but to allow the advection of sludge and water to be treated.

The filter tank E2 is constructed by filling a carrier C2 having a specific gravity higher than that of water at a high density to a predetermined height. In addition, at a position lower than the predetermined height of the second partition wall W2 separating the filtration tank E2 and the treatment water tank T1 provided adjacent to the filtration tank E2, a filtration wall portion for allowing the water to be treated to flow freely. 4 is formed. As a result, the water to be treated including the sludge flowing to the filtration tank E2 is transferred to the carrier C.
2 is filtered through the deposited filtration layer B, and contains almost no solid content.
Advected to 1. The second partition wall W2 is connected at an upper end portion to the side wall of the septic tank, and the treated water tank T is viewed in plan.
1 is disposed so as to be hidden below the filtration tank E2.

The filter wall portion 4 is formed in a lattice or slit shape to prevent the carrier C2 from advancing but allow the sludge or the water to be treated to migrate. Further, the carrier C is provided under the deposited filtration layer B.
A diffuser tube D2 is provided as a stirrer that diffuses air into the filter tank E2 and agitates the inside of the filter tank E2. Then, the carrier can be washed and regenerated. Also,
The air diffuser pipe D2 diffuses air toward the advection wall 3, and bubbles generated by the aeration pass through the advection wall 3 and rise along the advection wall 3 on the carrier flow tank E1 side. The advection wall diffuser Da, which is configured so as to be evacuated, and the air diffused similarly toward the filter wall, and bubbles generated by the diffuser are separated from the filter wall 4.
And a filter wall diffuser D configured to be raised along the filter wall 4 on the treated water tank T1 side.
b is provided to wash the advection wall portion 3 and the filtration wall portion 4 to prevent clogging and the like.

Here, the advection wall 3 and the filtration wall 4
Is provided at a position lower than a predetermined height, which is the height of the upper end of the pile of the sedimentary filtration layer B, so that the to-be-treated water always passes through the sedimentary filtration layer B after a predetermined distance. Any structure may be used as long as it allows the advection of water and filters the water to be treated in the sediment filtration layer B. The carrier C1 has a specific gravity of about 0.98, and the carrier C2 has a specific gravity of about 1.0.
08, and generally has a specific gravity of 0.9-1.
It is formed in about two.

Further, the treatment water tank T1 is provided in FIG.
As shown in FIG. 3, an air lift pump A for transferring the water to be treated is provided in the first anaerobic filter bed tank N1.
The sludge generated by the regeneration of No. 2 can be transferred together with the water to be treated from the inside of the filtration tank E2 to the first anaerobic filter bed tank N1.

The carrier fluidizing tank E1 and the filtering tank E2
The carrier holding member 10 for preventing the carrier C1 in the tank from flowing out even if a large amount of water to be treated flows into the septic tank slightly below the steady water level of the carrier C1, It is composed of mesh materials 11, 11 finer than C2, and is adhered and fixed to the peripheral wall or partition wall of the septic tank. The carrier holding member 10 has an opening 12 in a part thereof.
And an opening / closing mechanism is formed by opening / closing the opening as an outflow preventing member 13 with the opening / closing lid member 13a. As a result, even if air is diffused in the carrier fluidizing tank E1 and the filtering vessel E2 to form convection of the water to be treated, the flow is formed so as to flow smoothly without being hindered by the carrier holding member 10. You. In the case where the carriers C1 and C2 are filled in the carrier fluidizing tank E1 and the filtering vessel E2 or the carriers C1 and C2 are exchanged, after the water to be treated is drawn down to lower the water level, the opening 12 Is used as a carrier charging section, and the carrier can be easily charged and discharged, so that the maintenance can be easily performed.

Further, the carrier holding member 10 is provided with a diffuser tube insertion hole 14 through which the diffuser tube D1 can be inserted and removed, and the air supply tube D1a connected to the diffuser tube D1 has In a state in which the diffuser tube D1 is fixed in the carrier flow tank E1, a flow-out preventing member 15 for covering the diffuser tube insertion hole 14 is integrally connected to form a blocking mechanism for preventing the carrier from flowing out. is there. In addition, the air supply pipes for the diffuser pipe D1 and the air lift pump A are arranged in the space above the filtration tank, and the piping above the carrier flow tank E1 is minimized. Thereby, even when it is necessary to take out the air diffuser D1 out of the septic tank, for example, for maintenance of the air diffuser D1, the air diffuser D1 can be easily inserted and removed through the air diffuser insertion hole 14, The carrier holding member 1
Work can be performed with almost no decomposition of 0 or the like.

Further, sludge and the like generated by peeling when the carrier is washed and regenerated by the diffuser D2 can be returned to the first anaerobic filter tank first chamber N1 by a return pump P2 comprising an air lift pump. is there. In addition, the diffuser D
2. Air supply to the advection pump P1 and the return pump P2
The process is performed by a control device (not shown), and the water to be treated is transferred from the pretreatment tank to the carrier fluidized tank, and the first anaerobic filter bed tank N1 and the second chamber N2 on the upstream side of the carrier fluidized vessel are moved. In order to perform a washing step of operating the advection pump and performing the water level adjustment step, and then operating the diffuser tube D2 to wash the carrier in the carrier flow tank so as to bring the carrier into a low water level state. Supply air (see FIG. 3).

The treated water tank T1 allows only the clean supernatant portion that has passed through the filtration tank E2 to be discharged to the outside, flows into the disinfecting tank Q provided above the sedimentation tank T2, and contacts the solid disinfectant Q1. After being disinfected, it is discharged outside the tank.

[Alternative Embodiment] In the above embodiment, an example in which the aerobic treatment tank is the carrier fluidizing tank E1 has been described. However, a carrier for supporting microorganisms is accommodated, and the water to be treated is held so that it can be filtered. In addition, a septic tank provided with a biological filtration tank provided with a carrier washing device for washing the carrier can be similarly used. In the above example, the filtration tank E2
It can be seen that exhibits a function similar to a biological filtration tank.

[Brief description of the drawings]

FIG. 1 is a vertical sectional side view of a septic tank according to the present invention.

FIG. 2 is a longitudinal perspective view of a main part of a septic tank according to the present invention.

FIG. 3 is a diagram showing an operation state of a return pump.

[Explanation of symbols]

 C1, C2 carrier D1, D2 carrier cleaning device E1, E2 aerobic treatment tank N1, N2 pretreatment tank P2 return pump P1 advection pump

Claims (4)

[Claims] 1. A carrier flowing tank provided with a carrier washing device for accommodating and holding a carrier formed to be flowable together with water to be treated in a state in which microorganisms are supported, and for washing the carrier. Provided with at least one pretreatment tank for pretreating the water to be treated flowing into the carrier fluidizing tank upstream of the carrier fluidizing vessel, and washing the sludge generated by washing the carrier upstream of the carrier fluidizing vessel. A purification tank provided with a return pump for transferring to the tank, wherein a transfer pump for transferring the water to be treated from the pretreatment tank to the carrier flow tank is provided, and the carrier is washed according to a washing operation timing. A septic tank equipped with a control device that enables the advection pump to be switched on and off. 2. A biological filtration tank which contains a carrier for supporting microorganisms, holds the water to be treated so as to be capable of being filtered, and includes a carrier washing device for washing the carrier. At least one pretreatment tank for pretreating inflowing water to be treated upstream of the biological filtration tank, and returning the washed sludge generated by washing the carrier to a tank upstream of the carrier fluidization tank. A purifying tank provided with a pump, wherein an advection pump for transferring the water to be treated from the pretreatment tank to the biological filtration tank is provided, and the advection pump is operated and stopped according to a cleaning operation timing for cleaning the carrier. A septic tank equipped with a control device that enables switching. 3. A carrier flowing tank provided with a carrier cleaning device for holding and holding a carrier formed to be flowable together with water to be treated in a state in which microorganisms are supported, and a carrier washing device for washing the carrier. Provided with at least one pretreatment tank for pretreating the water to be treated flowing into the carrier fluidizing tank upstream of the carrier fluidizing vessel, and washing the sludge generated by washing the carrier upstream of the carrier fluidizing vessel. A method for operating a purification tank provided with a return pump for transferring to a tank, wherein the water to be treated is transferred from the pretreatment tank to the carrier flow tank, and the tank on the upstream side of the carrier flow tank is brought into a low water level state. A method for operating a purification tank, comprising: performing a washing step of washing a carrier in the carrier fluidization tank after performing a water level adjustment step. 4. A biological filtration tank which contains a carrier for supporting microorganisms, holds the water to be treated so as to be capable of being filtered, and is provided with a carrier washing device for washing the carrier. At least one pretreatment tank for pretreating inflowing water to be treated upstream of the biological filtration tank, and returning the washed sludge generated by washing the carrier to a tank upstream of the carrier fluidization tank. A method for operating a septic tank provided with a pump, wherein a water level adjustment step is performed in which water to be treated is transferred from the pretreatment tank to the biological filtration tank, and a tank on the upstream side of the biological filtration tank is set to a low water level. And then performing a washing step of washing the carrier in the biological filtration tank.