JP2892888B2 - Septic tank - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a septic tank provided with a contact aeration tank downstream of an anaerobic filter bed tank.

[0002]

2. Description of the Related Art Conventionally, in this type of septic tank, for example, a sedimentation tank is provided downstream of a contact aeration tank, and the supernatant from the sedimentation tank is guided to a disinfection tank, where it is disinfected and then discharged. Had become.

[0003]

However, when it is desired to increase the processing capacity of such a septic tank, it is necessary to increase the size of the septic tank itself, for example, by providing multiple stages of contact aeration tanks, thereby limiting the space. However, there were drawbacks that were difficult to cope with.

[0004] It is therefore an object of the present invention to provide a compact septic tank having a large treatment capacity without substantially increasing the space occupied by the entire septic tank and increasing the treatment capacity of sewage.

[0005]

Means for Solving the Problems] characterizing feature of the septic tank according to the present invention for achieving this object, under the anaerobic filter bed tank
The flow, a septic tank contact materials were provided aeration tank contact touch you have decorated, the contact aeration tank, filled with a filter medium tare
With an opening that can take in water to be treated
While immersed placed the biological filtration tank provided with parts, the organism
The bottom of the filtration tank is flush with the filtrate inlet of the filtrate discharge device.
And a ventilation device .

[0006]

[Function] The water to be treated can be taken into the upper part of the contact aeration tank.
Function opening , fill the filter medium, and take the water to be treated on the upper side.
The biological filtration tank having a interrupt enable opening while immersed placed on the bottom of the biological filtration tank, since the filtrate inlet of the filtrate discharge device and the aeration device and are arranged, the contact
The water to be treated in the contacting aeration tank flows from the opening through the biological filtration tank.
To the bottom while contacting the filter media,
Drained out of the biological filtration tank through the filtrate inlet of the liquid discharger
It is. More specifically, the aeration device constantly diffuses a small amount of gas to supplement the oxygen required for the aerobic microorganisms growing on the filter medium in the biological filtration tank. by discharging the filtrate, the water to be treated under the gap filter media filled in the biological filtration tank through the
In addition to physically trapping suspended suspensions in the water to be treated by filtration, not only can microorganisms living in the filter medium be trapped by micro-organisms that cannot be physically trapped, but also these can be decomposed, In a physical filtration treatment, it is possible to decompose an organic substance present as a solution that cannot be trapped in principle. Also, by the aeration device,
By performing a so-called backwashing bubbling short optionally a relatively large amount of air, e directed from bottom to top
Removes excess biofilm and the like adhering to the filter media
And is removed upward along with the air. So
Therefore, it is possible to prevent an excessive biofilm or the like from adhering to the filter medium and causing clogging. At this time,
The removed biofilm, etc. floats in the water to be treated as sludge.
However, the biological treatment tank is
Because it is immersed in the aeration tank,
The sludge that has been collected floats easily into the contact aeration tank.
It will be processed again.

[0007]

According to the conventional septic tank, only the SS can be removed by sedimentation separation in the sedimentation tank. On the other hand, the septic tank according to the present invention does not require a sedimentation tank, but is filtered by a biological filtration tank. Biological treatment can be performed at the same time as removal of SS and minute organic matter, so the processing capacity is increased while minimizing the space occupied by the entire septic tank, and SS and BOD are more effectively reduced. Can be reduced. In addition, a configuration in which the biological filtration tank is separated from the contact aeration tank and provided downstream thereof is also conceivable. However, such a separated configuration not only increases the space occupied by the entire septic tank, but also results when the biological filtration tank is backwashed. In contrast to the necessity of a return path for returning the separated sludge and the like to be separated to the inflow side contact aeration tank, in the case of the configuration of the present invention, the separated sludge at the time of backwashing is in the contact aeration tank. Since it is mixed with circulating water and treated, there is no need to provide such a return path, and there is an advantage that the whole can be formed into a compact one.

[0008]

Embodiments of the present invention will be described below. As shown in FIG. 1, an anaerobic filter bed tank N composed of an anaerobic filter bed tank first chamber N1 and an anaerobic filter bed tank second chamber N2, and a contact aeration tank E are flowed from the upstream side by natural advection. A septic tank is provided so as to flow in this order.

The anaerobic filter bed tank N is provided with filter beds F1 and F2 in order to grow anaerobic microorganisms that anaerobically decompose organic substances in the water to be treated and to fix their biofilms. The contact aeration tank E is used to fix aerobic microorganisms that decompose the remaining organic matter in the water to be treated and perform nitrification of ammoniacal nitrogen. 10 mm square, eye width 50 to 80 m in plan view
m is formed integrally with the honeycomb tube net of m, and a circulating flow of the water to be treated is generated in the tank.
A large number of upward air diffusion holes were formed in a PVC pipe in order to contact the aerobic microorganisms fixed in the well with the water to be treated containing organic matter and to supply air for supplying oxygen necessary for the aerobic microorganisms. A pair of air diffusers D1, D1 are horizontally arranged along the partition wall at the bottom of the gap formed between the partition wall W and the contact material C on the anaerobic filter bed second chamber N2 side to supply air. Connected to a blower for air. Air diffuser D1, D
1 and the width of the gap between the partition wall W and the contact material C, the flow rate of the water to be treated rising through this gap is 30 cm.
/ S, and the flow rate of the water to be treated descending in the contact material C is set to a circulation flow of about 10 cm / s.

In order to prevent clogging due to excessive biofilms and the like adhering to the contact material C, air is constantly or intermittently bubbled as necessary to remove the excess biofilms and the like. A backwash pipe R for stripping as stripped sludge is provided below the contact material C. In order to prevent the concentration of suspended solids, BOD, etc. in the contact aeration tank E from becoming too large, a part of the liquid to be treated in the contact aeration tank E is constantly or intermittently removed from the anaerobic filter bed tank. The air lift pump A rises from the bottom of the contact aeration tank E so that the air can be returned to the first chamber N1 to accelerate the denitrification treatment and the like. A return path B is provided.

Next, a biological filtration tank 1 showing a unique configuration of the present invention will be described. The biological filtration tank 1 accommodates a packed layer 3 formed by uniformly filling a large number of small plastic filter media having a diameter of 30 mm or less into a cylindrical casing 2 having a length extending from near the upper surface to near the lower surface of the contact material C. The contact member C is vertically disposed substantially at the center of the contact member C in a state where the contact member C is placed on a support base 4 having four legs. The casing 2 is provided with a bottom 5 whose upper end is formed in an opening 6 for opening near the upper end level of the contact material C to take in the water to be treated. In the biological filtration tank 1, a filtrate discharge air lift pipe 8, which is a filtrate discharge device having a filtrate intake port 7 below the packed bed 3, rises along the inner wall or the outer wall of the biological filtration tank 1, and enters the disinfection tank Q. An air supply pipe 9 for air lift is connected near the lower end of the filtrate discharge air lift pipe 8 from the blower.
The biological filtration tank 1 also has an aeration device 10 serving as a diffuser tube for supplementing oxygen to aerobic microorganisms grown in the packed bed 3 and a backwashing tube for preventing clogging of the packed bed 3. A large number of upwardly diffusing holes formed in a PVC pipe are connected to the blower and horizontally disposed below the packed bed 3. A switching valve is provided so that the flow rate of air supplied to the aeration apparatus 10 can be easily switched between a small flow rate during normal air diffusion and a large flow rate during intermittent backwashing. In addition, an air diffuser for supplying oxygen to the aerobic microorganisms grown in the packed bed 3 and a packed bed 3
May be provided separately without being used as a backwash tube for preventing clogging.

The amount of water to be pumped from the air lift pipe 8 is set to be about 1.5 to 2 times the average amount of raw water flowing into the septic tank, and the flow rate of the water to be treated descending the packed bed 3 is 5 cm /
The flow rate of air supplied to the air lift tube 8 and the cross-sectional area of the filling tank 3 are set so as to be about s or less, and when the water level in the contact aeration layer E falls to the lower control limit water level, the air lift tube 8 A level sensor and an electromagnetic valve that opens and closes in conjunction with the level sensor are provided so that the supplied air automatically stops.

The liquid discharged from the filtrate discharge air lift pipe 8 is guided to a disinfection tank Q. At the entrance of the disinfecting tank Q, a cartridge T containing a solid disinfectant is disposed.
A plurality of slit-shaped openings for inflow and outflow of the water to be treated are formed in a lower portion thereof. The water to be treated that has come into contact with the disinfectant in the cartridge T passes under a baffle provided in the middle of the disinfection tank, and overflows and is discharged.

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 sectional side view of a septic tank in an embodiment.

[Explanation of symbols]

 E contact aeration tank N anaerobic filter bed tank 1 biological filtration tank 7 filtrate inlet 8 filtrate discharge device 10 aeration device

──────────────────────────────────────────────────続 き Continuing on the front page (72) Dai Harada, Inventor 2 at Takamatsu, Kosai-cho, Koga-gun, Shiga Prefecture Inside the Kubota Shiga Plant. Kubota Corporation Shiga Factory (56) References JP-A-3-232588 (JP, A) JP-A-3-83695 (JP, U) JP-A-2-125799 (JP, U) (58) Field (Int.Cl. ⁶ , DB name) C02F 3/00

Claims (1)

(57) [Claims] A contact material is provided downstream of an anaerobic filter tank (N).
A septic tank provided with aeration tank (E) against touch of the (C) are then furnished to the contact aeration tank (E) filling, it is filled with filter media
Opening provided with layer (3) and capable of taking in water to be treated on the upper side
A biological filtration tank (1) provided with a part (6) is immersed and arranged, and a filtrate inlet (7) of a filtrate discharge device (8) and an aeration device (10) are provided at the bottom of the biological filtration tank (1). And a septic tank.