JP3507968B2 - Wastewater treatment equipment - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wastewater treatment apparatus, and more particularly to a relatively small scale for performing wastewater treatment by an anaerobic / aerobic filter bed method in which an aerobic filter bed is combined with an aerobic filter bed after the anaerobic filter bed. The present invention relates to a wastewater treatment device suitable for a wastewater treatment facility.

[0002]

2. Description of the Related Art In recent years, even in a relatively small-scale wastewater treatment facility, removal of nitrogen and phosphorus is often required to prevent eutrophication. Conventionally, in small-scale sewage treatment facilities, filter bed type biological treatment equipment has been widely used because it is easy to maintain and manage, and when removal of nitrogen and phosphorus is required, it is anaerobic and favorable. The air-bed method is often used.

FIG. 3 shows a conventional wastewater treatment apparatus by the above-mentioned anaerobic / aerobic filter bed, in which an aerobic filter bed 2 is arranged after an anaerobic filter bed 1. The inflowing sewage (drainage) flows into the raw water tank 3 from only the sand basin equipment or the pretreatment equipment in which the sand basin equipment and the first sedimentation basin are combined, and then is sent to the anaerobic filter bed 1 by the submersible pump. The water anaerobically treated by the anaerobic filter bed 1 is sent to the aerobic filter bed 2 for aerobic treatment, and then sent to the treated water tank 4. Part of the water in the treated water tank 4
It is returned to the anaerobic filter bed 1 as circulating water (nitrifying liquid), and the amount of water corresponding to the inflow water is sent to the sterilization tank 5 and sterilized, and then discharged into a river or the like.

[0004] The sludge in the anaerobic filter bed 1 is regularly withdrawn from the bottom of the sludge and concentrated in the sludge thickening tank 6,
The sludge is sent to the sludge storage tank 7 and carried out in the state of concentrated sludge. Further, the cleaning wastewater of the aerobic filter bed 2 is returned to the raw water tank 3 and reprocessed. In the figure, P is a pump, M is a motor, and C is a compressor.

[0005]

In the conventional wastewater treatment equipment based on the anaerobic / aerobic filter method, the pretreatment equipment is only the sand basin equipment or the sand basin equipment and the first sedimentation basin. Contaminant concentration of influent in the anaerobic filter bed (B
OD, SS, T-N, T-P, etc.) are high, and a large capacity is required for good anaerobic treatment. Furthermore, if the concentration of pollutants in the inflow water to the anaerobic filter bed is high,
Although the amount of sludge generated is large, the anaerobic filter bed is not usually specially cleaned and the sludge is pulled out manually on a regular basis. Was sometimes worse. In addition, the sludge in the anaerobic filter bed is retained in the form of sediment or adhered to the contact material, but it is in a very unstable state, so it is easily affected by flow rate fluctuations, and when the amount of inflow water is large. In some cases, sludge leaked and flowed into the aerobic filter bed.

On the other hand, in an aerobic filter, it is necessary to reduce the BOD volume load in order to carry out a sufficient nitrification reaction, and since it also has a filtration mechanism, it is desirable that the SS load be as low as possible. ,As aforementioned,
If sludge leaks from the anaerobic filter bed, the processability of the aerobic filter bed will be greatly affected.

Further, the surplus sludge is first drawn directly from the settling basin or the anaerobic filter bed, or is drawn through a sludge thickening tank to be treated. Since it is often carried out in the area, the amount of sludge generated greatly affects the running cost. In order to reduce the amount of sludge generated, it is necessary to make the sludge retention time in the anaerobic filter bed very long and perform sufficient anaerobic decomposition, or reduce the capacity by making the sludge concentration as high as possible. However, conventionally, these points are not sufficient.

[0008] Therefore, an object of the present invention is to provide a wastewater treatment apparatus capable of performing stable wastewater treatment in a short time and efficiently recovering excess sludge at a high concentration.

[0009]

In order to achieve the above object, the wastewater treatment equipment of the present invention treats wastewater by an anaerobic / aerobic filter method in which an aerobic filter bed is combined in a subsequent stage of the anaerobic filter bed. waste water treatment apparatus odor performing Te, between the front Symbol anaerobic filter bed and aerobic basin, it is characterized in that was installed on the floatation separator.

Also, the sludge generated in the aerobic filter bed is washed.
Raw water tank installed upstream of the anaerobic filter bed together with the purified water
A pipe for returning to the
Is the treated water containing sludge leaking from the anaerobic filter bed.
Being supplied, raw water and the aerobic filter bed
The nitrification solution extracted from the above is settled on the anaerobic filter bed.
The sludge is fed to the bottom of the anaerobic filter bed so that it is stirred.
It is characterized by being

The pressure levitation separation device is, as is well known,
It can be treated for a short time, and separated sludge can be treated at a high concentration.
Capable of being collected and not affected by the concentration of pollutants in raw water
Since it has features such as the fact that when a pressurized flotation device is installed between the anaerobic filter bed and the aerobic filter bed, the removal rate of suspended components is higher than in the precipitation process. , The inflow load to the aerobic filter bed can be reduced, the capacity of the aerobic filter bed can be reduced, and the sludge leaked from the anaerobic filter bed can be prevented from flowing into the aerobic filter bed, so that stable treatment can be performed. .

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will now be described in more detail with reference to the drawings. First, FIG. 1 shows a reference example of a waste water treatment device in which a pressure floating separation device is installed in a front stage of an anaerobic filter bed. The same components as those of the conventional apparatus shown in FIG. 3 will be described with the same reference numerals.

In this wastewater treatment apparatus, a raw water tank 3, a pressurized flotation separator 11, an anaerobic filter bed 1, an aerobic filter bed 2, a treated water tank 4, and a sterilization tank 5 are arranged in this order from the upstream side of the flow of treated raw water. The sewage that has been arranged is sent from the raw water tank 3 to the pressure flotation separation device 11 and is subjected to a flotation process, and then an anaerobic treatment and an aerobic treatment are sequentially performed.

After the inflowing sewage is subjected to sand settling and screen treatment, it flows into the raw water tank 3 and is sent to the pressure floating separation device 11 by an underwater pump. A flow rate adjusting function can be added to the raw water tank 3 if necessary. Pressure levitation separator 1
The raw water sent to No. 1 is mixed with the pressurized water supplied from the pipe 12 at the inlet to the pressurized flotation separator 11, and the suspended component in the raw water adheres to the fine bubbles generated from the pressurized water to give an apparent specific gravity. Becomes smaller and is separated as floating sludge (floss) in the upper part of the tank of the pressure floating separation device 11. The floating sludge is scraped off by the scraping machine 13 and sent from the path 14 to the sludge storage tank 7. The sludge concentration at this time is 3 to 5%, which is higher than the gravity concentration in the conventional sludge thickening tank 6.

Also, sludge generated from the anaerobic filter bed 1 and the aerobic filter bed 2 is returned to the pressure flotation separation device 11 through the raw water tank 3 through the pipes 1a and 2a and treated to generate sludge. It is possible to achieve a single point and a high concentration. Therefore, in a relatively small-scale wastewater treatment facility in which the amount of sludge generation has a great influence on the running cost, the running cost can be greatly reduced.

Further, a part of the water treated by the pressure flotation device 11 is taken out to the pipe 15 on the outlet side, pressurized by the pump, and mixed with the compressed air supplied from the compressor in the mixing tank 16. After that, the raw water is supplied and mixed from the pipe 12 as pressurized water.

Since the water treated by the pressure flotation device 11 has a higher removal rate of suspended components as compared with the ordinary precipitation treatment, the inflow load on the anaerobic filter bed 1 is reduced, and the amount thereof is reduced. Therefore, the capacity of the anaerobic filter bed 1 can be reduced. In addition, in the levitation treatment, easily floatable components such as hair, oil, and scum can be almost completely removed.
Occurrence of clogging of contact material and scum on the anaerobic filter bed 1 is reduced.

In addition, since stable and favorable treatment is possible in the anaerobic filter bed 1, the treatability in the aerobic filter bed 2 into which the water treated in the anaerobic filter bed 1 flows is also improved.
The aerobic filter bed 2 shown in FIG. 1 has a contact oxidation part filled with a contact material in the upper part and a filtration part filled with a filter material in the lower part. And is circulated to the anaerobic filter bed 1 through a pipe 17.

FIG. 2 shows that between the anaerobic filter bed and the aerobic filter bed,
One aspect of the present invention of a wastewater treatment device equipped with a pressure flotation device
It shows an example of an embodiment . The same components as those of the apparatus shown in FIG. 1 are designated by the same reference numerals and detailed description thereof will be omitted.

In this waste water treatment apparatus, a raw water tank 3, an anaerobic filter bed 1, a pressure flotation separator 11, an aerobic filter bed 2, a treated water tank 4, and a sterilization tank 5 are arranged in this order from the upstream side of the flow of the treated raw water. The inflowing sewage is arranged from the raw water tank 3 to the anaerobic filter bed 1 and is anaerobically treated, and then is floated by the pressure flotation / separation device 11, and further is aerated by the aerobic filter bed 2. After air treatment, it is sent to the treated water tank 4 and the sterilization tank 5 for treatment.

The anaerobic filter bed 1 is of a type in which the lower part is a sludge sedimentation part and the upper part is filled with a contact material, and the inflowing sewage from the raw water tank 3 is discharged from the middle part of the aerobic filter bed 2. The sludge that has been extracted and circulated through the pipe 17 is supplied so as to stir the sludge that has precipitated in the lower portion of the anaerobic filter bed 1. In this anaerobic filter 1, denitrification and anaerobic decomposition of organic matter are mainly performed. In addition, as a general rule, the anaerobic filter bed 1 does not perform sludge withdrawal and washing of the filter bed, but retains the sludge in the filter bed as long as possible to promote the decomposition of the sludge and reduce the amount thereof. it can.

The water treated in the anaerobic filter bed 1 including the leaked sludge is sent to the pressure flotation / separation device 11, and the pipe 1
It is mixed with the pressurized water supplied from 2 and flows into the tank.
The suspended component in the water floats as floating sludge (floss) on the upper part of the tank by the action of fine bubbles from the pressurized water, is scraped by the scraping machine 13 and is sent to the sludge storage tank 7. The sludge concentration is 3 to 5% as in the above, which is higher than the conventional concentration.

The water floated by the pressure flotation separator 11 is sent to the aerobic filter bed 2. In the aerobic filter bed 2, part of the water treated in the upper catalytic oxidation part is withdrawn from the middle stage by a pump into the pipe 17 and circulates, and the water filtered in the lower filtration part is treated water tank 4 Sent to the sterilization tank 5
After being sent to and processed, it is discharged to rivers.

The sludge generated in the aerobic filter bed 2 is returned to the raw water tank 3 through the pipe 1a together with the cleaning drainage, reduced in the anaerobic filter bed 1, and then treated in the pressure flotation separator 11. Therefore, as in the above, it is possible to achieve a single sludge generation site and a high concentration.

As described above, by installing the pressure levitation separation device 11 in the preceding stage of the aerobic filter bed 2, the levitation treatment in the pressure levitation separation device 11 removes suspended components as compared with the ordinary precipitation treatment. Since the rate is high, the amount of suspended components of the flotation treated water sent to the aerobic filter bed 2 is small and the inflow load to the aerobic filter bed 2 is small. Therefore, the capacity of the aerobic filter bed 2 should be reduced. You can

Further, in the floating treatment of the pressure floating separation device 11, if the SS concentration is 2000 to 3000 mg / l or less, the treated water quality is not affected by the raw water concentration, so that stable treatment can be performed. Further, even if sludge leaks from the anaerobic filter bed 1, it is treated by the pressure flotation separation device 11,
Sludge leaking from the anaerobic filter bed 1 does not flow into the aerobic filter bed 2 and does not affect the processability of the aerobic filter bed 2.

[0027]

As described above, the wastewater treatment equipment of the present invention is a wastewater treatment equipment for performing wastewater treatment by the anaerobic / aerobic filter bed method in which the aerobic filter bed is combined with the aerobic filter bed after the anaerobic filter bed. Since a pressure flotation device is added, stable wastewater treatment can be performed in a short time, excess sludge can be efficiently collected at high concentration, and the capacity of anaerobic filter bed and aerobic filter bed can be reduced. It can also be planned.

[Brief description of drawings]

FIG. 1 is a system diagram showing a reference example of a wastewater treatment device to which the present invention is applied.

[2] One of the present invention of the applied wastewater treatment apparatus of the present invention
It is a systematic diagram showing an example of an embodiment .

FIG. 3 is a system diagram showing an example of a conventional wastewater treatment device.

[Explanation of Codes] 1 ... Anaerobic filter bed, 2 ... Aerobic filter bed, 3 ... Raw water tank, 4 ... Treated water tank, 5 ... Sterilization tank, 7 ... Sludge storage tank, 11 ... Pressurized flotation separation device

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-6-47398 (JP, A) JP-A-2-31895 (JP, A) JP-A-6-39368 (JP, A) JP-A-7- 328692 (JP, A) JP 58-153599 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) C02F 3/28-3/34 C02F 1/24 C02F 9/00

Claims (3)

(57) [Claims] 1. A wastewater treatment device for treating wastewater by an anaerobic / aerobic filter method in which an aerobic filter bed is combined with an aerobic filter bed after the anaerobic filter bed, wherein between the anaerobic filter bed and the aerobic filter bed. The wastewater treatment equipment is characterized in that a pressure levitation separation device is installed in the. 2. The sludge generated in the aerobic filter bed is washed and discharged.
Return it together with water to the raw water tank installed upstream of the anaerobic filter bed.
In addition to installing a pipe, the pressure floating separation device,
Supply of treated water containing sludge leaking from the anaerobic filter bed
The wastewater treatment apparatus according to claim 1, wherein the wastewater treatment apparatus is a wastewater treatment apparatus. 3. Extracted from raw water and the aerobic filter bed
The nitrification liquid stirs the sludge that has settled on the anaerobic filter bed.
So that it is supplied to the lower part of the anaerobic filter bed.
The wastewater treatment device according to claim 1 or 2, which is regarded as a characteristic .