JP2002102882A - Sewage cleaning method and apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sewage cleaning method and apparatus capable of always stably cleaning sewage corresponding to a temporary change in the discharge amount of the sewage. SOLUTION: In the sewage cleaning method, a high water level position (HWL) and a low water level position (LWL) are provided in the upper part of an anaerobic treatment tank 2 to form a sewage flow rate adjusting part 3 between both positions. An aerobic treatment tank 5 equipped with a filter medium 6, a sedimentation tank 10 and a disinfection tank 11 are arranged on the downstream side of the anaerobic treatment tank 2 in this order, and a backwashing pipe 8 for back washing the filter medium 6 and an air lift pump 9 for returning sludge peeled by backwashing the filter medium 6 are provided to constitute the sewage cleaning tank A. When the liquid level of sewage in the flow rate adjusting part 3 is set in the vicinity of the lower water level position, the return of sludge is performed intermittently.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for purifying sewage. More specifically, the upper part of the anaerobic treatment tank is a wastewater flow rate adjustment unit, by intermittently performing sludge return from the aerobic treatment tank provided downstream of the anaerobic treatment tank,
The present invention relates to a sewage purification method capable of efficiently performing sewage treatment by coping with a temporal change in sewage drainage amount, and a sewage purification tank therefor.

[0002]

2. Description of the Related Art Conventionally, a method for purifying sewage discharged from general households or the like using activated sludge is known, and anaerobic treated sewage is continuously subjected to aerobic treatment, and separated sludge is separated. A method for purifying sewage is generally used. Regarding the above method, for example, Japanese Patent Application Laid-Open No. 58-1
43888, Heikai 3-86094, Heikai 4-2
15892, JP-A-4-99295, JP-A-11-
Various publications such as 77071 disclose various prior arts.

By the way, the discharge pattern of sewage in general households and the like is closely related to the life time of human beings, and the temporal fluctuation of the discharge amount, that is, the discharge amount of sewage peaks in the morning, In the daytime and late at night, it is common to see a dramatic decrease in emissions. If there is no response to the above-mentioned temporal fluctuation of the discharge amount, if the discharge amount of the sewage temporarily exceeds the treatment capacity of the sewage septic tank, the sewage that has not been subjected to the sewage treatment overflows and is discharged,
There is a problem that the sludge settled in the purification tank is discharged together with the wastewater and pollutes the water quality.

[0004]

On the other hand, in recent years, so-called combined treatment septic tanks, which treat human waste and domestic wastewater in a single tank, are becoming popular in ordinary households. It has the above problems. In order to respond to temporal fluctuations in the amount of sewage discharge, if a storage tank for temporarily storing sewage is provided, and a certain amount of sewage is constantly transferred from the storage tank to the merger treatment / purification tank, Anaerobic and aerobic treatment with sludge can be performed stably. However, if the above-mentioned storage tank is attached to the merged treatment septic tank, the device itself becomes large,
Problems also arise in terms of securing land. Therefore, there is a need for a general household use of a purification device that is small in size, has a small installation area, and is capable of treating sewage in a manner that is sufficiently adapted to temporal fluctuations in sewage discharge. Solution to Problem The present invention solves the above problems, copes with temporal fluctuations of sewage discharged from general households, etc., and can always and stably purify sewage, and a compact sewage purification method therefor. It is an object to provide a sewage septic tank.

[0005]

That is, according to the present invention, a high water level position and a low water level position are provided at the upper part of the anaerobic treatment tank, between which a wastewater flow rate adjusting part is provided, and the downstream of the anaerobic treatment tank is provided. An aerobic treatment tank equipped with a filtering material, a sedimentation tank,
A sewage system comprising a disinfecting tank arranged in this order, a backwash pipe for backwashing the filter medium, and an air lift pump for returning sludge separated by backwashing the filter medium for returning sludge. In the septic tank, there is provided a sewage purification method characterized by intermittently returning sludge when the liquid level of the sewage in the flow control section is near the low water level position.

In the above-mentioned sewage treatment tank, sewage is purified mainly by aerobic microorganisms in the aerobic treatment tank. The aerobic microorganisms are usually used by adhering to the surface of the filter medium, and if the sewage treatment is performed for a long time, a microbial membrane is formed on the surface of the filter medium and thickens. If the thickening progresses, it becomes difficult to pass the sewage, so it is necessary to blow air by backwashing treatment and vigorously agitate the filter medium to remove the microbial membrane. This backwashing process is performed periodically, but in the present invention, it is performed when the discharge of sewage is extremely reduced, such as at midnight. The microbial membrane peeled off by the backwashing process precipitates at the bottom of the tank as sludge, and this sludge is returned to the anaerobic treatment tank so as not to be entrained downstream together with the wastewater. The present invention is characterized in that the sludge is returned intermittently. By intermittently returning sludge, fluctuations in the water level position in the aerobic treatment tank can be minimized, and the return operation can be performed efficiently. At the same time, since the aerobic treatment is performed with the minimum water level position fluctuation width, the sewage can be highly and stably purified.

Further, according to the present invention, an aerobic process having a high water level and a low water level at the upper part of the anaerobic treatment tank and a flow rate adjusting part between the high water level and the low water level, and a filtering material provided downstream of the anaerobic treatment tank. A treatment tank, a sedimentation tank, and a disinfection tank are arranged in this order, a backwash tube for backwashing the filter material, and a sludge return for returning sludge separated by backwashing the filter material. A sewage treatment tank provided with an air lift pump and a sludge return means for intermittently returning sludge is provided.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below in detail with reference to the drawings. FIG.
1 is a sectional view of a sewage purification tank A according to the present invention.

First, the sewage purification method of the present invention will be described. Sewage such as night soil and domestic wastewater discharged from general households flows into the anaerobic treatment tank 2 from the sewage inlet 1 to separate sediment and perform anaerobic treatment. A high water level (HWL) and a low water level (LWL) are provided in the upper part of the anaerobic treatment tank 2, and a flow rate adjusting unit 3 is provided between the two. Detecting means (not shown) for detecting the high water level (HWL) when the inflowed sewage accumulates and the water level rises
Operates to operate the sewage transfer pump 4, and the sewage is transferred to the aerobic treatment tank 5.

On the other hand, the aerobic treatment tank 5 is provided with a filter material 6 to which aerobic microorganisms are adhered, and the sewage in an atmosphere made aerobic by aeration air constantly blown through a diffuser 7. Perform purification. If the purification of the sewage is performed continuously, a film of the microorganisms is generated and thickened on the surface of the filter medium 6 to prevent the passage of the sewage.
In the backwash, the air supplied from the air supply device B (blower) via the backwash air line 13 is diffused in the backwash pipe 8,
This is performed by blowing into the treated water to vigorously flow and stir the filter medium 6. The microbial membrane peeled off from the surface of the filter material 6 precipitates as sludge on the bottom of the aerobic treatment tank 5.
On the other hand, the air line 14
Is supplied to the air lift pump 9 for returning sludge, and the settled sludge is returned to the anaerobic purification tank 2 by an air lift.

The treated water purified in the aerobic purification tank 5 is then moved to a sedimentation tank 10 where the sediment is separated, overflows and is disinfected in a disinfection tank 11.
Thus, the purified wastewater is discharged from the wastewater outlet 12.

[0012] The air supply device B includes an air control valve V for backwashing.
₁ and a timer T ₁ for controlling the same, an air lift air control valve V ₂ and a timer T ₂ for controlling the air control valve V ₂ are provided, respectively. Controls time on / off.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The method of the present invention was carried out according to the above-mentioned method using the sewage purification apparatus A and the air supply apparatus B shown in FIG.

[0014]

[Example 1] Extreme discharge of sewage in ordinary households
The method of the present invention was performed at decreasing midnight. At midnight
Is the water level position of the anaerobic treatment tank 2
In this state, in the state shown in FIG.
Backwashing and sludge return were performed. That is, first, FIG.
Backwash air control valve V provided in the air supply device B shown in FIG. ₁
The backwashing air control valve control timer T₁By predetermined time,
Control to open, and send air to backwash tube 8 for a predetermined time.
Winded and backwashed. The microbial membrane is peeled off by back washing,
It settled at the bottom of the temper septic tank 5. Symbol X is aerobic purification
The separated sludge settled at the bottom of the tank 5 is shown. Also, L₁Is
This shows the water level position at the time when backwashing was started.

Next, according to the pattern shown in FIG.
After the backwash was completed, the sludge was intermittently returned to the anaerobic treatment tank 2 at regular intervals. That is, a predetermined time air lift air regulating valve V ₂ provided in the air supply device B by airlift air regulating valve control timer T _2, and the on-off control to open at regular intervals, for the air sludge return The air was blown to the air lift pump 9 and the sludge was returned intermittently. FIG. 4 schematically shows the situation. In this embodiment, since the air lift was performed intermittently for a short time, it was possible to suppress the lowering of the water level position in the aerobic treatment tank 5 and efficiently return the sludge. That is, since the intermittent operation is performed, the water level position in the aerobic treatment tank 5 is maintained at a relatively high position, so that the head of the air lift pump is reduced, and the sludge is efficiently returned by the operation of the air lift pump for a short time. We were able to. Incidentally, in FIG. 4, L ₂ represents the lowest level position when carrying out the intermittent return of the present invention, L ₃ represents the lowest level position when carrying out the continuous operation of the conventional method. When carrying out the intermittent return water level position of aerobic treatment tank 5 from the above L _2, since varied between L ₁ in FIG. 3 could be the width and the lowest, in the aerobic treatment tank 5 Purification of sewage could be performed highly and stably.

[0016]

Example 2 The method of the present invention was carried out in the same manner as in Example 1, except that the backwashing and sludge return patterns were changed to those shown in FIG. As can be clearly understood from FIG. 5, the intermittent operation of the backwash and the intermittent operation of returning the sludge were performed in the same cycle and in the same phase. In this case, since the control of the air supply from the air supply device B (blower) to the backwash pipe 8 and the air lift pump 9 is performed simultaneously, the control mechanism can be simplified. In addition, since the backwash was performed intermittently, the separated sludge was uniformly distributed in the aerobic treatment tank 5, and the quality of the sludge return water was equalized. Furthermore, since the backwashing was also performed a plurality of times, the removal of the microbial membrane from the filter medium could be sufficiently performed, and the treatment capacity of the sewage was greatly improved.

[0017]

Example 3 The method of the present invention was carried out in the same manner as in Example 1, except that the backwashing and sludge return patterns were changed to those shown in FIG. As can be clearly seen from FIG. 6, after the backwashing, the sludge was returned with the phase shifted. However, the intermittent operation of returning sludge was performed in the same cycle as the backwash. As a result, since the sludge is returned after the backwashing is completed, the separated sludge can be efficiently returned to the anaerobic treatment tank 2, and the operation time of the equipment related to the backwashing and the sludge return can be reduced. did it.

[0018]

Example 4 The method of the present invention was carried out in the same manner as in Example 1, except that the backwashing and sludge return patterns were changed to those shown in FIG. As can be clearly understood from FIG. 7, first, the sludge was returned, and then the above-mentioned backwash was performed intermittently at the same cycle as the return of the sludge by shifting the phase. However, the stop time of the intermittent operation in the backwash was set to a time sufficient for the separated sludge to settle. As a result, the sludge that has settled is returned first, so that the sludge is efficiently removed from the anaerobic treatment tank 2.
The operation time of equipment related to backwashing and sludge return could be shortened.

In any of the embodiments described above, the sludge returned to the anaerobic treatment tank 2 is settled and treated by a known means, for example, periodically withdrawing.

[0020]

According to the sewage purification method of the present invention, a high water level and a low water level are provided at the upper part of an anaerobic treatment tank, and a wastewater flow control part is provided between them. An aerobic treatment tank provided, a sedimentation tank, and a disinfection tank are arranged in this order, and a backwash tube for backwashing the filter material, and for returning sludge separated by backwashing the filter material. In the sewage purification tank provided with the sludge returning air lift pump, the sludge is intermittently returned when the liquid level of the sewage in the flow rate adjusting section is near the low water level position.

In the method of the present invention, the upper part of the anaerobic purification tank is used as a flow control tank, and the sludge is returned intermittently.
The aerobic treatment can be performed by minimizing the fluctuation range of the water level position in the aerobic septic tank. As a result, sewage purification processing can be performed highly and stably in response to temporal fluctuations in sewage discharge. Therefore, it is possible to provide a sewage purification method capable of always stably purifying sewage by coping with temporal fluctuation of sewage discharged from general households and the like.

Further, in the method of the present invention, the sludge can be returned intermittently and the backwash can be performed intermittently. In this way, the quality of the sludge return water is equalized, and the backwashing is also performed a plurality of times, so that the microbial membrane can be sufficiently removed from the filter medium,
Wastewater treatment capacity is greatly improved. In addition, the intermittent operation of sludge return and backwashing can be easily performed by simply turning on and off the air fed to the sludge return air lift pump and the backwash pipe by means of a timer or the like, without requiring any special control equipment. It can be carried out. Also, the sewage treatment tank for carrying out the method of the present invention can be made compact so that it can be used in ordinary households.

[Brief description of the drawings]

FIG. 1 is a sectional view of a sewage purification apparatus according to the present invention.

FIG. 2 is a diagram showing an operation pattern according to the first embodiment.

FIG. 3 is a schematic diagram showing backwashing in Example 1.

FIG. 4 is a schematic diagram showing return of sludge in the first embodiment.

FIG. 5 is a diagram illustrating an operation pattern according to a second embodiment.

FIG. 6 is a diagram showing an operation pattern according to a third embodiment.

FIG. 7 is a diagram showing an operation pattern of a fourth embodiment.

[Explanation of symbols]

Reference Signs List 1 sewage inlet 2 anaerobic treatment tank 3 flow rate adjustment unit 4 sewage transfer pump 5 aerobic treatment tank 6 filter material 7 diffuser pipe 8 backwash pipe 9 air lift pump for returning sludge 10 sedimentation tank 11 disinfection tank 12 drainage outlet 13 for backwash Air line 14 Air lift air line A Sewage treatment tank B Air supply device L ₁ Water level position at the time of starting backwashing in Example 1 L ₂ Minimum water level position when sludge is intermittently returned in Example 1 L ₃ Conventional method minimum level position V ₁ backwash air regulating valve V ₂ airlift air regulating valve T ₁ backwash air regulating valve control timer T ₂ airlift air regulating valve control timer X sludge when the sludge was continuously returned

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor: Shinya Hirota 1048 Kadoma, Kadoma, Osaka Prefecture Inside Matsushita Electric Works Co., Ltd. (72) 72) Inventor Kenshi Sato 1048 Kadoma, Kadoma, Osaka Prefecture Inside Matsushita Electric Works, Ltd. (72) Inventor Takayoshi Nakaoka 1048 Odaka, Kazuma, Kadoma, Osaka Prefecture Inside Matsushita Electric Works, Ltd. 1048 Kadoma, Kadoma, Fumonma-shi Matsushita Electric Works F-term (reference) 4D027 AB07 AB14 AB14 4D040 BB42 BB82 BB91

Claims (6)

[Claims] An aerobic treatment tank provided with a high water position and a low water position at the upper part of an anaerobic treatment tank, between which a wastewater flow rate adjusting part is provided, and a filtering material provided downstream of the anaerobic treatment tank,
A sedimentation tank and a disinfection tank are arranged in this order, a backwash tube for backwashing the filter medium, and a sludge return air lift pump for returning sludge separated by backwashing the filter medium. Wherein the sludge is returned intermittently when the liquid level of the wastewater in the flow rate adjusting section is near the low water level position in the wastewater purification tank provided. 2. The sewage purification method according to claim 1, wherein the backwashing is performed intermittently, and the intermittent backwashing operation is performed in the same cycle and in the same phase as the sludge return. 3. The method according to claim 1, wherein the backwashing is performed intermittently, and the phase of sludge return is shifted after the backwashing so as to be performed intermittently in the same cycle as the backwashing. 4. An intermittent operation in which the backwashing is performed intermittently, the sludge return phase is shifted before the backwashing, and intermittently in the same cycle as the backwashing, and the backwashing and the sludge return are performed intermittently. 2. The sewage purification method according to claim 1, wherein the stop time of the sewage is the same predetermined time. 5. The sludge returning and the intermittent operation of the backwashing are performed by controlling on / off of air fed into the sludge returning air lift pump and the backwashing pipe.
The sewage purification method according to any one of claims 1 to 4. 6. An aerobic treatment tank provided with a high water position and a low water position at the upper part of the anaerobic treatment tank and a flow rate adjusting portion between the high water position and the low water position, and provided with a filtering material downstream of the anaerobic treatment tank;
A sedimentation tank and a disinfection tank are arranged in this order, a backwash tube for backwashing the filter medium, and a sludge return air lift pump for returning sludge separated by backwashing the filter medium. A wastewater purification tank provided with sludge return means for intermittently returning sludge.