JPH05111692A - Method for controlling septic tank - Google Patents

Abstract

PURPOSE:To minimize the release of settled sludge while well maintaining nitrification and denitrification treatments by intermittent aeration. CONSTITUTION:A 1st chamber N1 of an anaerobic filter bed tank, a 2nd chamber N2 of the anaerobic filter bed tank and a contact aeration tank E are provided in this order from a sewage inflow side. The aeration in the contact aeration tank E is intermittently executed. The treated water in the contact aeration tank E is returned to the 2nd chamber N2 of the anaerobic filter bed tank at the time of the aeration and is returned to the 1st chamber N1 of the anaerobic filter bed tank at the time of stopping the aeration.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a septic tank in which an anaerobic filter bed tank comprising a anaerobic filter bed tank first chamber and an anaerobic filter bed tank second chamber and a contact aeration tank are provided in this order from the sewage inflow side. The present invention relates to a method for controlling a septic tank in which aeration in the contact aeration tank is intermittently performed and the treated water in the contact aeration tank is returned to the anaerobic filter bed tank.

[0002]

2. Description of the Related Art Intermittent aeration is performed by supplying oxygen to aerobic microorganisms in the contact aeration tank by aeration to perform aerobic treatment such as nitrification, and at the same time, to stop anaerobic Anaerobic treatment such as denitrification is carried out by assisting the function of microorganisms, that is, nitrification and denitrification are performed in a well-balanced manner.
In order to save power for aeration, the treated water in the contact aeration tank is always returned to the anaerobic filter bed first chamber while performing such intermittent aeration. It was

[0003]

However, in the conventional method in which the treated water in the contact aeration tank E is constantly returned to the anaerobic filter bed first chamber, the returned water causes the anaerobic filter bed first chamber to be returned. The sludge in the settling pool was constantly stirred and was easily transferred to the downstream side, and there was a risk that the sludge would be discharged and a satisfactory purification process could not be performed. Therefore, an object of the present invention is to suppress advection and discharge of settled sludge while maintaining good nitrification and denitrification treatment by intermittent aeration.

[0004]

To achieve this object, the characteristic means of the method for controlling a septic tank according to the present invention is to intermittently perform aeration in the contact aeration tank and to perform the aeration in the contact aeration tank. When the aeration is performed, the treated water is anaerobic filter bed second
It is returned to the chamber and returned to the anaerobic filter bed first chamber when the aeration is stopped. Its action and effect are as follows.

[0005]

In the aeration, the treatment liquid in the contact aeration tank is agitated and the peeled sludge is dispersed in the whole, so that there is no particularly high concentration of the peeled sludge. Therefore, returning the treated liquid to the second chamber of the anaerobic filter bed tank, which originally has less sedimentation sludge, is more effective in advancing the sludge to the contact aeration tank side than returning it to the first chamber of the anaerobic filter bed tank, which has much sedimentation sludge. Few. When the aeration is stopped, the separated sludge in the contact aeration tank tends to settle, so that the treated water having a high sludge concentration can be returned. Therefore, in this case, if the treated water having a high sludge concentration is returned to the anaerobic filter bed first chamber, the sludge can be separated and settled to some extent here. There is less advection of settled sludge to the contact aeration tank compared to. Therefore, the treated water in the contact aeration tank is returned to the anaerobic filter bed second chamber during aeration, and when the aeration is stopped, the anaerobic filter tank first
By returning the sludge to the chamber, the outflow of sludge can be suppressed as compared with the case of the conventional method in which the sludge is always returned to the anaerobic filter bed first chamber.

[0006]

In other words, it is possible to keep the nitrification and denitrification treatment in good condition by intermittent aeration, and at the same time, to minimize the discharge of settled sludge.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a vertical side view of the septic tank of the present application. This septic tank comprises, from the upstream side, an anaerobic filter bed tank N composed of an anaerobic filter bed tank first chamber N1 and an anaerobic filter bed tank N2, a contact aeration tank E,
The settling tank P is provided in this order. Hereinafter, each tank N, E, and P is further explained. A manhole M ′ is provided above the anaerobic filter bed tank N.
The anaerobic filter bed tank first chamber N1 removes the floating suspension suspended in the treated water flowing from the inflow port 2 by floating or settling, and the anaerobic decomposition treatment of organic substances similarly to the anaerobic filter bed tank second chamber N2. And denitrification of the nitrification solution described later. Therefore, in the anaerobic filter bed first chamber N1 and the anaerobic filter bed second chamber N2, in order to make the anaerobic microorganisms that anaerobically decompose the organic matter inhabit and to be fixed as a biofilm thereof, the plastic first ,
Second filter beds F1 and F2 are provided. Here, the first filter bed F1 of the anaerobic filter bed tank first chamber N1 is formed of a honeycomb tubular filter medium mesh with a coarse lattice spacing that is unlikely to be clogged, and the second filter bed F2 of the anaerobic filter bed tank second chamber N2 is used. Is formed of a honeycomb tubular filter medium mesh that is denser than the first filter bed F1 of the anaerobic filter bed first chamber N1. Next, the contact aeration tank E will be described. The contact aeration tank E mainly oxidizes and decomposes organic substances in treated water and nitrifies ammoniacal nitrogen, and is provided with a plastic contact material C for fixing aerobic microorganisms for this purpose. Further, a circulating flow of the treated water is generated in the contact aeration tank E so that the treated water containing an organic substance is brought into good contact with the aerobic microorganisms fixed on the contact material C, and oxygen necessary for the aerobic microorganisms is generated. An air diffuser D for supplying the air from the blower L into the tank for giving is provided in the contact aeration tank E.
In the contact aeration tank E, although the aerobic microorganisms are mainly inhabited and used, anaerobic microorganisms such as facultative anaerobic bacteria also inhabit, and the aeration is stopped and the anaerobic is stopped. When the state is close to the state, some of these anaerobic microorganisms are likely to work, and so-called denitrification treatment for further decomposing the nitrification solution into nitrogen gas or the like can be performed to some extent. Further, the air lift pump A and the return passage B are provided in order to return the nitrification liquid and the separated sludge in the contact aeration tank E to the anaerobic filter bed tank N to settle the sludge on the upstream side and accelerate the denitrification process. It is equipped. A manhole M is provided above the contact aeration tank E. Next, the precipitation tank P will be described.
The tank P is provided with a disinfecting tank Q, and the drainage from the contact aeration tank E is subjected to sedimentation and removal of the suspended suspension thereof, followed by disinfection and discharge from the discharge port 3.

The method for controlling the above septic tank will be described below. Aeration in the contact aeration tank E and air supply to the air lift pump are performed by using one blower L in common. The aeration is from the blower L to the air diffuser D
Air is supplied to the chamber intermittently by opening and closing the solenoid valve Vd. On the other hand, the air lift pump is always operating. Va is a flow rate adjusting valve for the air lift pump, but this may be adjusted to an appropriate flow rate first and then left as it is thereafter. The return passage B is branched so that the return water can be returned to either the first chamber N1 or the second chamber N2 of the anaerobic filter bed tank, and the solenoid valve Vd is provided in the middle of the branch pipe to the second chamber N2. An electromagnetic valve Vb is provided to interlock with the anaerobic filter, and when the aeration is performed, the electromagnetic valve Vb is opened and the treated water is returned to the anaerobic filter bed second chamber N2. When the aeration is stopped, the electromagnetic valve Vb is closed and the anaerobic filter is closed. It is designed to be returned to the floor tank first chamber N1. In the figure, S is a sequence control device that interlocks both solenoid valves Vd and Vb so that the solenoid valve Vb opens when the solenoid valve Vd opens and the solenoid valve Vb closes when the solenoid valve Vd closes. In the septic tank having the above-described configuration, the treated water in the contact aeration tank E is supplied to the anaerobic filter bed second chamber N during aeration.
In the case of the conventional method in which the treated water in the contact aeration tank is always returned to the anaerobic filter bed first chamber by returning it to No. 2 and returning to the anaerobic filter bed first chamber when aeration is stopped. Compared with, the outflow of sludge can be reduced. still,
A membrane filtration device R may be provided in the anaerobic filter bed first chamber N1. The pump for operating the filtration membrane device R is not used, and the height of the overflow port from the first chamber N1 of the anaerobic filter bed tank is made sufficiently higher than the water level of the second chamber N2. 1
A height difference is produced between the water levels of the chamber N1 and the second chamber N2, and the filtration pressure is obtained by the difference in the water heads. The treated water in the anaerobic filter bed first chamber N1 is admitted to the second chamber N2 through this membrane filtration device without overflowing, so that fluctuations in the flow rate are alleviated and the suspended suspension to the downstream side is reduced. The advection of suspended solids is further reduced, the denitrification process becomes easier, and at the same time, the release of suspended suspended matters such as sludge is more reliably prevented.

It should be noted that reference numerals are given in the claims for convenience of comparison with the drawings, but the present invention is not limited to the configurations of the accompanying drawings by the entry.

[Brief description of drawings]

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

[Explanation of symbols]

 N Anaerobic filter bed tank N1 Anaerobic filter bed tank 1st chamber N2 Anaerobic filter bed tank 2nd chamber E Contact aeration tank

Front Page Continuation (72) Inventor Kazuyuki Honda, 1 Takamatsu, Kosai-cho, Koga-gun, Shiga Prefecture 1 Stock company, Kubota Plant (72) Inventor Katsumi Hamada, 1-share, Takamatsu, Koga-gun, Shiga Prefecture Kubota Company, Ltd. Inside the Shiga factory

Claims (1)

[Claims] 1. An anaerobic filter bed first chamber (N
1), the anaerobic filter bed tank (N) consisting of the second chamber (N2) of the anaerobic filter bed tank and the contact aeration tank (E) are provided in this order, in contrast to the septic tank, in the contact aeration tank (E) A method of controlling a septic tank, in which the treated water in the contact aeration tank (E) is returned to the anaerobic filter bed tank (N) while performing air intermittently, wherein the treated water is at the time of the aeration. The anaerobic filter bed second
A method for controlling a septic tank which is returned to the chamber (N2) and is returned to the anaerobic filter bed first chamber (N1) when the aeration is stopped.