JPH0737758Y2 - Sewage septic tank - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a sewage purification tank.

[Prior art] Conventionally, as a septic tank for domestic human waste and gray water, a small combined septic tank that has an anaerobic treatment tank, an aerobic treatment tank, a sedimentation tank, and a disinfection layer tank, and performs purification treatment while sequentially advancing sewage. Sewage septic tanks such as are widely known.

Although the treated sewage treated above has a BDD value of 20 mg / l or less, it is generally B
It was difficult to maintain a DD value of 10 mg / l or less, and nitrification was not always sufficient.

Therefore, for the purpose of advanced treatment of sewage, a method is proposed in which a tertiary treatment tank is further connected to the above-mentioned sewage purification tank, aeration treatment is performed in this tertiary treatment tank to perform advanced treatment of organic substances, and nitrification is promoted to remove ammonia. Has been and is being implemented.

[Problems of conventional technology]

However, in the case of aeration treatment by the above-mentioned tertiary treatment tank, although nitrification of wastewater is promoted during aerobic treatment, PH of mud may be too low. Occur in large numbers,
These have the drawbacks of eating up the biofilm necessary for purification treatment, increasing the amount of peeled sludge, and lowering the treatment capacity.

[Problems to be solved by the device]

In view of the above problems, the present invention has been made for the purpose of providing a sewage purification tank capable of sufficiently leveling the PH of discharged water and suppressing the generation of Daphnia when the sewage purification tank is provided with a tertiary treatment tank. It is a thing.

[Technology for solving problems]

That is, the sewage purification tank of the present invention comprises an anaerobic treatment tank, an aerobic treatment tank, a settling tank and a disinfection tank, and in the sewage purification tank that purifies while sequentially advancing sewage, the treatment discharged from the sewage purification tank A tertiary treatment tank for further purifying water is connected to the sewage treatment tank, and the tertiary treatment tank is provided with an air diffuser for supplying air from a blower provided separately from the aerobic treatment tank. The air supply pipe for supplying air to the air diffuser is branched from the air diffuser, and a large bubble generating air diffuser is provided in the branched pipe via an electromagnetic valve that is intermittently operated by a timer. ..

〔Example〕

 Next, an embodiment of this invention will be described.

FIG. 1 is a sectional view of an embodiment of the present invention, and FIGS. 2 (a) and 2 (b) are graphs showing an operating state of a solenoid valve of the embodiment of the present invention.

The sewage purification tank 1 of this invention comprises anaerobic treatment tanks 2A and 2B, an aerobic treatment tank 3, a settling tank 4 and a disinfection tank 5, and in the sewage purification tank 1'which performs purification treatment while sequentially advancing sewage, A tertiary treatment tank 6 for further purifying the treated water discharged from the septic tank is connected to the sewage purification tank 1 ', and the tertiary treatment tank 6 is supplied with an air diffuser from a blower 8 provided separately from the aerobic treatment tank 3. 7 is provided, and the air supply pipe 8B for supplying air to the diffuser pipe 7 is branched from this blower 8,
A solenoid valve 9 is intermittently operated by a timer 8A on the branch pipe.
An air diffuser 10 for generating large bubbles is provided via the above.

In FIG. 1, 3A indicates an air diffuser provided in the aerobic treatment tank 3, and 3B indicates a blower for supplying air to the air diffuser 3A.

In the above, the intermittent control for the solenoid valve 9 is such that, as shown in FIG. 2 (a), ON / OFF is repeated in a cycle of several hours, and as shown in FIG. 2 (B), during the OFF time. The control that intermittently activates ON is performed for a short time.

These are appropriately selected in consideration of the nature, quantity, inflow pattern, climatic conditions, etc. of sewage.

[Action]

In this invention, the sewage discharged from the sewage purification tank 1'is further purified by the tertiary treatment tank 6. In this case,
Since high-rate aeration and large-bubble aeration are intermittently performed in the wastewater, the amount of oxygen supplied is sufficient at the time of high-rate aeration, BOD is removed, and nitrification proceeds. On the other hand, when large air bubbles are diffused, the amount of oxygen that can be dissolved in the wastewater is small, and the circulation flow generated by the rise of the large bubbles enables highly efficient contact between the wastewater and the biofilm, which is more than the low oxygen supply amount. The decrease in PH due to nitrification of erythrocyte is suppressed and the generation of Daphnia magna is also suppressed.

Therefore, by the tertiary treatment, for example, the treated water BOD value can be maintained at 10 ppm or less, and sufficient sewage treatment is performed.

Further, as shown in Fig. 2 (b), when the ON is intermittently operated for a short time during the OFF time, the treated water is agitated by the fine air bubbles, so that the contact efficiency between the treatment liquid and the microorganism is high. Is improved and a more uniform treatment is possible.

Further, in the pretreatment device, when the air lift pump 11 which constantly circulates the liquid in the contact aeration tank is constantly returned and circulated, more stable treatment becomes possible.

〔effect〕

As described above, this invention has two features in the tertiary treatment tank.
Lower BOD value and PH than before due to different types of aeration
It is possible to obtain a leveled and stabilized treated water.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of an embodiment of the present invention, and FIGS. 2 (a) and 2 (b) are graphs showing an intermittent aeration state of the embodiment.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Dai Harada, 1 of 2 Takamatsu, Kosai-cho, Koga-gun, Shiga Prefecture Kubo Tatekko Co., Ltd. Shiga Factory (72) Kazuyuki Honda, Takamatsu, Kosai-cho, Koga-gun, Shiga Prefecture No.1 Kubo Tetsuko Co., Ltd. Shiga Factory

Claims (1)

[Scope of utility model registration request] 1. A sewage purification tank comprising an anaerobic treatment tank, an aerobic treatment tank, a settling tank and a disinfection tank, which successively purifies the wastewater while advancing it, and further purifies the treated water discharged from the wastewater purification tank. A tertiary treatment tank for treatment is connected to the wastewater purification tank, and an air diffuser for supplying air from a blower provided separately from the aerobic treatment tank is provided in the tertiary treatment tank, and the diffuser pipe is provided from the blower. A sewage purification tank characterized in that an air supply pipe for supplying air is branched, and an air diffusion pipe for generating large bubbles is provided in the branched pipe via an electromagnetic valve intermittently operated by a timer.