JP2776699B2 - Septic tank - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a contact aeration tank provided downstream of an anaerobic filter bed tank, the contact aeration tank comprising a first chamber and a second chamber in the flow direction. The present invention relates to a purification tank provided with an anaerobic treatment return path for returning a liquid to be treated in an air tank to the anaerobic filter bed tank.

[0002]

2. Description of the Related Art Conventionally, as this type of septic tank, an anaerobic treatment return pipe for individually returning a liquid to be treated from the first chamber of the contact aeration tank and the second chamber of the contact aeration tank to the anaerobic tank is provided. Similarly, the liquid to be treated in the first chamber of the contact aeration tank and the liquid to be treated in the second chamber of the contact aeration tank are similarly provided with a return path for anaerobic treatment having a structure of being directly returned to the anaerobic filter bed tank. There was a septic tank.

[0003]

According to the above-mentioned conventional septic tank, the separated sludge in the second chamber of the contact aeration tank is returned to the anaerobic filter bed tank. Is reduced and the nitrified liquid is further denitrified in the anaerobic filter tank, so that the denitrification step is effectively performed. On the other hand, the dissolved amount of oxygen in the second chamber of the contact aeration tank is reduced. Since the liquid to be treated that has become excessive flows into the anaerobic filter bed tank,
The amount of dissolved oxygen in the anaerobic filter tank increases, and the anaerobic treatment activity of the anaerobic filter tank decreases. In addition, since the amount of water to be returned to the anaerobic filter bed tank increases due to the water to be treated from the first chamber and the second chamber of the contact aeration tank, the separated sludge generated from the first chamber of the contact aeration tank is removed by the contact aeration tank. Air tank 2
The BOD in the second chamber of the contact aeration tank increases, thereby increasing the processing load in the second chamber of the contact aeration tank and increasing the BOD in the second chamber of the contact aeration tank.
There is a disadvantage that the degree of transparency of the liquid to be treated in the chamber is reduced, and a high degree of purification of the liquid to be treated is prevented.

[0004] Accordingly, an object of the present invention is to provide a denitrification process efficiently without increasing the processing load on the second chamber of the contact aeration tank in view of the above drawbacks. It is to provide a septic tank that does not lower.

[0005]

In order to achieve this object, a feature of the present invention is to provide a return for aerobic treatment in which a liquid to be treated is returned from the second chamber of the contact aeration tank to the first chamber of the contact aeration tank. Since the road is provided, the operational effects obtained from the road are as follows.

[0006]

In other words, by providing a return path for aerobic treatment from the contact aeration tank second chamber of the aeration treatment liquid to the contact aeration tank first chamber, the separated sludge in the contact aeration tank second chamber is provided. The aerated treatment liquid containing the nitric acid and the nitrification liquid is returned to the first chamber of the contact aeration tank, and the liquid to be treated in the first chamber of the contact aeration tank is returned to the anaerobic filter bed tank through the return path for anaerobic treatment. . Therefore, the separation sludge is less likely to accumulate in the contact aeration tank second chamber, thereby reducing the processing load on the contact aeration tank second chamber and at the same time between the contact aeration tank first chamber and the second chamber. By the circulation of the nitrification liquid, the denitrification treatment in the anaerobic filter bed tank is favorably performed.

Incidentally, the dissolved oxygen concentration in the second chamber of the contact aeration tank increases because the BOD decreases due to the decrease in the amount of stripped sludge, and the dissolved oxygen concentration in the returned aerated treatment liquid also increases. However, even if this aerated treatment liquid is returned to the anaerobic filter bed tank, if the treatment liquid is returned to the contact aeration tank first chamber and then returned to the anaerobic filter bed tank, the contact In the first chamber of the aeration tank, since the amount of separated sludge is large and the BOD is high, the dissolved oxygen concentration is lower than that of the second chamber. As a result, the dissolved oxygen concentration of the liquid to be treated returned to the anaerobic filter bed tank is too low. As a result, the activity of the anaerobic filter tank against anaerobic treatment can be prevented from lowering.

Further, since the sludge in the second chamber of the contact aeration tank can be reduced, the visibility of the second chamber of the contact aeration tank is improved, and the inspection of the second chamber of the contact aeration tank becomes easy. Become. Further, the amount of the liquid to be treated to be circulated to the contact aeration tank second chamber can be reduced, so that the burden on the contact aeration tank second chamber is reduced.

[0009]

Therefore, according to the septic tank of the present invention, the denitrification treatment of the liquid to be treated is performed well, and the contact aeration tank second
Since the processing load on the chamber is reduced, the quality of the waste liquid flowing from the septic tank can be improved, and a decrease in the activity of the septic tank can be suppressed, so that stable purification can be performed over a long period of time. Further, since the inspection is facilitated, a septic tank with easy maintenance can be provided.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. As shown in FIG. 1, from the upstream side, the first anaerobic filter tank
An anaerobic filter bed tank N comprising a chamber N1 and an anaerobic filter bed tank N2, a contact aeration tank E comprising a contact aeration tank first chamber E1 and a second chamber E2, a sedimentation tank P, and a disinfection tank Q The treatment liquid is provided so as to flow in this order by natural advection to form a purification tank.

In the anaerobic filter bed tank N, anaerobic microorganisms for anaerobically decomposing organic substances in the liquid to be treated and denitrifying nitrate nitrogen grow, and a filter bed F for fixing the biofilm.
1 and F2 are provided in the anaerobic filter bed first chamber N1 and the anaerobic filter tank second chamber N2, respectively.

In the contact aeration tank E, contact materials C1 and C2 for fixing aerobic microorganisms for decomposing the remaining organic substances in the liquid to be treated and nitrifying ammoniacal nitrogen are respectively placed in the contact aeration tank. One chamber and a contact aeration tank second chamber are provided, a circulating flow of the liquid to be treated is generated in each tank, and the liquid to be treated containing an organic substance is brought into good contact with the aerobic microorganisms fixed on the contact material C, In addition, diffuser pipes D1 and D2 for supplying air for giving necessary oxygen to the aerobic microorganisms are provided in the first chamber of the contact aeration tank and the second chamber of the contact aeration tank, respectively.

In order to prevent the contact material C from being clogged due to excessive attachment of a biofilm or the like, the contact material C
Backwash tubes R1 and R2 are provided below the contact materials C1 and C2, respectively, for releasing bubbles and causing collision with the wastewater and peeling off excess biofilm and the like as peeled sludge.

[0014] The first chamber E of the contact aeration tank by the separated sludge.
The anaerobic treatment return path A1 for returning the liquid to be treated containing the exfoliated sludge and the nitrifying liquid to the anaerobic filter bed first chamber N1 so as not to increase the BOD in 1 and to denitrify the nitrifying liquid. A return pipe A communicating with the air lift pipe A11 and the upper part of the air lift pipe A11 to guide the liquid to be treated to the anaerobic filter bed tank N.
12 are provided.

Further, in order to prevent an increase in the amount of exfoliated sludge and an excessive increase in BOD in the second chamber of the contact aeration tank, and to denitrify the nitrification liquid, the aeration treatment liquid containing the exfoliated sludge and the nitrification liquid is contacted with the contact aeration treatment liquid. Return path A for aerobic treatment returned to the first air chamber E1
2 is an air lift tube A21 and its air lift tube A2.
And a return pipe A22 for communicating the liquid to be treated to the first chamber E1 of the contact aeration tank by being connected to the upper part of the first aeration tank 1.

Accordingly, the raw water to be treated flowing from the inflow port I is subjected to anaerobic treatment through the first and second chambers N1 and N2 of the anaerobic filter tank, and is decomposed. It undergoes aerobic treatment and is further nitrified and decomposed. In the first chamber E1 of the contact aeration tank, exfoliated sludge is generated by a circulating flow generated by aeration or an action of backwashing. The separated sludge and the nitrified liquid to be treated are returned to the anaerobic treatment return path A.
1 to return to the anaerobic filter bed tank N for decomposition and denitrification. On the other hand, the liquid to be treated which has been treated in the contact aeration tank first chamber E1 flows into the contact aeration tank second chamber E2 due to overflow, but also in the contact aeration tank second chamber E2 by aerobic treatment. Furthermore, nitrification and decomposition are performed. By the way, in the contact aeration tank second chamber E2, the nitrification liquid and the separated sludge are returned to the contact aeration tank first chamber E1 by the return path A2 for aerobic treatment, so that the nitrification liquid is denitrified or separated. The decomposition of the sludge is performed in the first contacting aeration tank E1 and the anaerobic filter bed tank N which is further returned, so that appropriate treatment is performed and the processing load in the second contacting aeration tank E2 is reduced. Will be reduced.

The treated liquid treated in the second chamber E2 of the contact aeration tank is transferred from the bottom of the second chamber E2 of the contact aeration tank to the settling tank P, and the supernatant of the settling tank P overflows. Each tank is formed so that it is guided to the disinfecting tank Q, where it is contacted with the solid disinfectant and disinfected, and then discharged from the discharge port Z to the outside.

Accordingly, the undiluted solution coming in from the inlet I is discharged after the above-mentioned treatment, so that it can be drained as highly purified treated water.

[Another embodiment] Another embodiment will be described below. 1) Although the anaerobic filter bed tank N used in this embodiment is divided into two tanks, the anaerobic filter bed tank N does not necessarily need to be divided into two tanks, and may be only one tank. Contact with the anaerobic filter bed tank N as the first chamber E1, the second chamber
What is necessary is just to apply to the septic tank with the chamber E2.

2) In this embodiment, both return routes A1, A
2 are air lift tubes A11, A21 and return tubes A12, A
The air lift pipes A11 and A21 and the return pipes A12 and A22 are not devised so as to improve the flow of the liquid to be processed and to perform good gas-liquid separation of air bubbles from the air pump. It is possible.

3) In the first embodiment, all the liquid returned from the second chamber of the contact aeration tank is returned to the first chamber of the contact aeration tank. However, the present invention is not limited to this configuration. No contact aeration tank other than return path A2 for aerobic treatment
There may be a flow path for returning the water to be treated from the chamber E2 to the anaerobic filter bed tank N, and a structure for directly returning a part of the return liquid in the aerobic treatment return path A2 to the anaerobic filter bed tank. It may be.

4) FIG. 2 shows another embodiment of the above configuration. That is, an air lift pipe A31 for guiding the liquid to be treated in the contact aeration tank second chamber E2 to the anaerobic filter bed tank N and the contact aeration tank first chamber E1 is provided, and a return pipe A32 is connected to the air lift pipe A31. The return pipe A32 to the branch pipe section B,
A part of the liquid to be treated that has flowed through the return pipe A32 falls downward and is returned to the first chamber E1 of the contact aeration tank, and a part of the liquid flows into the merge pipe A33.

Further, an anaerobic return path A1 for returning the liquid to be treated from the first chamber of the contact aeration tank to the anaerobic filter bed tank is provided, and a merging pipe A33 is connected to a return pipe A12 in the anaerobic return path A1. At the junction T, the junction A3
3 and the liquid to be processed flowing through the return pipe A12 are both returned to the anaerobic filter bed tank N.

When the configuration shown in FIG. 2 is adopted, a return path having the same processing capacity as that of the present embodiment can be installed in a small space. There are advantages such as widening and easy inspection.

As shown in FIG. 3, the branch pipe section B is provided with a partition section B1 for adjusting the amount of the liquid to be processed flowing from the return pipe A32 to the merging pipe A33 and a part of the liquid to be processed. Drop return hole B for returning to the contact aeration tank first chamber E1
2 and the return hole B2 is the lower contact aeration tank 1
The liquid to be treated is returned to the chamber E1.

5) Regarding the structure of the branch pipe section B,
A structure other than this may be used, and the flow path of the liquid to be treated can be freely switched so that the liquid to be treated from the contact aeration tank second chamber E2 can be transferred to either the anaerobic filter bed tank N or the contact aeration tank second chamber E2. It is possible to change to a structure that can be returned to other companies.

[0027] In the claims, reference numerals are written for convenience of comparison with the drawings, but the present invention is not limited to the configuration of the attached drawings by the entry.

[Brief description of the drawings]

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

FIG. 2 is a schematic view of a vertical side surface of a septic tank according to another embodiment of the present invention.

FIG. 3 is a longitudinal sectional side view of a branch pipe used in a return path according to another embodiment of the present invention.

[Explanation of symbols]

 N Anaerobic filter bed tank E Contact aeration tank E1 Contact aeration tank first chamber E2 Contact aeration tank second chamber A1 Return path for anaerobic treatment A2 Return path for aerobic treatment

Continuing from the front page (72) Inventor Kazuyuki Honda One of the two companies, Kubota Shiga Factory, Kosai-cho, Koga-gun, Shiga Prefecture (72) Inventor Katsumi Hamada Two shares of Takamatsu, Kosai-cho, Koga-gun, Shiga Prefecture (56) References JP-U 3-79895 (JP, U) (58) Field surveyed (Int. Cl. ⁶ , DB name) C02F 3/00-3/10

Claims (1)

(57) [Claims] 1. A contact aeration tank (E) is provided downstream of an anaerobic filter bed tank (N), and the contact aeration tank is separated from a first chamber (E1) and a second chamber (E2) in the direction of flow. A purification tank provided with an anaerobic treatment return path (A1) for returning the liquid to be treated in the contact aeration tank (E) to the anaerobic filter bed tank (N). A purification tank provided with an aerobic treatment return path (A2) for returning the liquid to be treated from the two chambers (E2) to the contact aeration tank first chamber (E1).