JPH10128359A - Waste water treatment apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance nitration and denitrification efficiency while making use of characteristics of a compact fixed bed high in treatment capacity by filling the lower part of a waste water treatment tank with a fixed carrier and charging a floating carrier in water of the upper part of the tank above the fixed carrier. SOLUTION: An aerobic filter bed 10 being a fixed bed has the filter material packed part 12 of a tank lower part packed with a filter material 11 being a fixed carrier such as lightweight aggregate or anthracite and a carrier floating part 13 wherein a floating carrier A is charged in the water of a tank upper part above the filter material packed part 12. Raw water flowing in the aerobic filter bed 10 from a raw water inflow pipe 14 is subjected to nitration treatment in the carrier floating part 13 and subjected to aerobic treatment and filtering treatment in the filter material packed part 12 to be discharged from a treated water discharge part 21. At this time, air is continuously introduced for an air diffusion pipe 19 to hold the interior of the aerobic filter bed 10 to a printing aerobic state not only to certainly perform aerobic treatment in the filter material packed part 12 but also to stably grow a large amt. of nitrifying bacteria in the carrier floating part 13.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a wastewater treatment apparatus, and more particularly to a wastewater treatment apparatus having a fixed floor for performing wastewater treatment in an aerobic state, a microaerobic state, or an anaerobic state.

[0002]

2. Description of the Related Art A fixed-bed wastewater treatment method, particularly an aerobic filter bed method, is often used in small-scale sewage treatment facilities because of its compactness and easy maintenance. Filter bed used in the aerobic filter method (aerobic filter bed)
Conventionally, filter media such as anthracite (fixed carrier)
A single bed type is generally used, but the height of the filter medium is limited to about 2 m in consideration of washing the filter bed.
The upper part could not be used effectively.

An improvement in this point is a two-bed aerobic filter bed 1 shown in FIG. This two-bed aerobic filter 1
A plastic contact material 3 having a high porosity is filled above a filter material 2 such as anthracite. By allowing the plastic contact material 3 to hold microorganisms, the plastic contact material 3 has a large amount in a filter bed having the same installation area. Of microorganisms to improve processing efficiency.

On the other hand, recently, even in relatively small-scale sewage treatment facilities, nitrogen removal is required in many cases, and maintenance is easy. Therefore, nitrogen removal is performed by an anaerobic aerobic filter method. It is becoming.

[0005]

However, conventional filter beds,
In particular, the aerobic filter bed is intended to mainly remove the SS and BOD components of the pollutants in the inflow water. Therefore, in order to sufficiently remove nitrogen (nitrification), it is necessary to reduce the amount of treated water. there were. Although the nitrification rate can be improved to some extent by using a two-bed system, it is difficult to stably grow the nitrifying bacteria in large quantities because the BOD oxidizing bacteria and the nitrifying bacteria are in a competitive relationship. Therefore, the water flow rate must be about 10 to 20 m ³ / m ² / day, which requires about twice the facility capacity as compared with the aerobic filter for removing BOD.

On the other hand, in recent years, it has been possible to increase the nitrification capacity by using a carrier entrapping and fixing nitrifying bacteria or using a carrier to which nitrifying bacteria are easily attached, and to perform nitrification denitrification in a relatively short time. A possible flotation method has been developed.

Accordingly, an object of the present invention is to provide a filter bed type wastewater treatment apparatus capable of improving the nitrification and denitrification efficiency while utilizing the characteristics of a compact fixed bed having a high treatment capacity.

[0008]

In order to achieve the above object, a wastewater treatment apparatus according to the present invention fills a lower part of a wastewater treatment tank with a fixed carrier and disposes a floating carrier in water in an upper part of the tank above the fixed carrier. In particular, the lower part of the aerobic filter bed which performs wastewater treatment by the anaerobic aerobic filter method is filled with a fixed carrier having a filtration function, and the upper part of the tank above the fixed carrier is introduced. The present invention is characterized in that a floating carrier entrapping and fixing nitrifying bacteria or a floating carrier to which nitrifying bacteria easily adhere is put into water.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in more detail with reference to the drawings. FIG. 1 shows an example of a wastewater treatment apparatus according to the present invention, and shows an example in which the present invention is applied to an aerobic filter bed which is a fixed bed.

The aerobic filter bed 10 comprises a filter medium filling section 12 at the lower part of the tank filled with a filter medium 11 as a fixed carrier such as a lightweight aggregate or anthracite, and a tank upper part above the filter medium filling part 12 as in the prior art. A raw water inflow pipe 14 above the carrier floating part 13 and a wedge wire screen 15 for preventing carrier outflow below the carrier floating part 13. A drainage pipe 16 connected to a compressor 18 is provided in a filter medium support layer 17 below the filter medium filling section 12, and treated water is provided below a water collection nozzle 20 at the bottom of the tank. Discharge pipes 21 are provided respectively.

As the floating carrier A, a carrier entrapping and fixing nitrifying bacteria or a carrier to which nitrifying bacteria easily adhere is used. Raw water flowing into the aerobic filter bed 10 from the raw water inflow pipe 14 is used as the floating carrier A. The part 13 comes into contact with the floating carrier A and is subjected to nitrification treatment by the nitrifying bacteria carried on the floating carrier A.

That is, the raw water flowing into the aerobic filter bed 10 from the raw water inflow pipe 14 is subjected to nitrification treatment in the carrier floating part 13, aerobic treatment and filtration treatment in the filter material filling part 12, and then to the treated water discharge pipe. It is discharged from 21.

At this time, air is continuously introduced from the air diffuser tube 19 to maintain the inside of the aerobic filter bed 10 in a predetermined aerobic state, so that the aerobic treatment (B
OD removal, etc.), and the carrier floating portion 13
Therefore, the nitrifying bacteria can be grown stably in a large amount, and thus the nitrification treatment can be performed in a relatively short time.
That is, by performing the nitrification treatment by suspending the carrier holding the nitrifying bacteria on the upper part of the aerobic filter bed 10, the nitrification can be performed with high treatment efficiency without increasing the water flow resistance. Further, the provision of the wedge wire screen 15 in the washing drainage pipe 16 can prevent the floating carrier A and the filter medium 11 from flowing out together with the washing wastewater when the filter medium 11 is washed.

The filter medium filling section 12 and the diffuser 1 at the bottom of the tank are provided.
9, the water collecting nozzle 20 and the like can adopt the same structure as a conventional aerobic filter bed, and therefore, detailed description thereof will be omitted.

FIG. 2 shows an example in which the above-described aerobic filter is applied to the anaerobic filter method. The raw water tank 30 having the screen 30a, the raw water and the washing are arranged from the upstream side of the flow of the treated raw water. Cleaning drainage tank 31 for storing wastewater, anaerobic filter bed 3
2, a pressurized flotation device 33, an aerobic filter bed 34, and a treated water tank 35 are arranged in this order, and the inflowing raw water is supplied from the raw water tank 30 to the anaerobic filter bed 32 via the washing / draining tank 31; After being subjected to anaerobic treatment in this anaerobic filter bed 32, it is subjected to levitation treatment in a pressure flotation / separation device 33, and further subjected to an aerobic filter bed 34.
After being subjected to aerobic treatment in, the water is sent to the treated water tank 35.

The anaerobic filter bed 32 is of a type in which the lower part is a sludge sedimentation section and the upper part is filled with a contact material. Along with the nitrified liquid that is extracted and circulated through the pipe 36,
The sludge settled in the lower part of the anaerobic filter bed 32 is supplied so as to be stirred. In the anaerobic filter bed 32, denitrification and anaerobic decomposition of organic substances are mainly performed. In addition, in this anaerobic filter bed 32, sludge is not pulled out and the filter bed is not washed in principle, and the sludge is retained in the filter bed as long as possible, thereby promoting the decomposition of sludge and reducing the amount of sludge. it can. The anaerobic filter bed 32 is provided with a diffuser 32a for preventing the inside of the filter bed from becoming excessively anaerobic.

The water treated by the anaerobic filter bed 32, including the sludge that leaks, is sent to the pressurized flotation device 33, mixed with the pressurized air mixed water supplied from the pipe 37, and flows into the tank. I do. The suspended component in the water floats on the upper portion of the tank as floating sludge (floss) by the action of fine bubbles generated from the pressurized air mixed water, is scraped by the scraper 33a, and is sent to the sludge storage tank 38.

The water levitated by the pressurized flotation device 33 is sent via the raw water inflow pipe 14 to the aerobic filter bed 34 having the carrier floating part 13 in which the carrier holding nitrifying bacteria floats as described above. Can be In the aerobic filter bed 34, a part of the water (nitrified liquid) that has been nitrified in the upper carrier floating portion 13 is discharged from the lower portion of the carrier floating portion 13 to the wedge wire screen 1.
5 and drained to the washing drainage pipe 16 through the pump 3
The water that has been drawn out to the pipe 36 by the 6P and circulated to the anaerobic filter bed 32 is sent to the treated water tank 35 from the treated water discharge pipe 21 by the aerobic treatment and the filtration treatment in the lower filter material filling part 12.

The sludge generated in the aerobic filter bed 34 is:
The wastewater is returned to the washing drainage tank 31 via the washing drainage pipe 16 and the pipe 39 together with the washing wastewater, and introduced into the anaerobic filter bed 32 together with the raw water to reduce the volume. . Therefore, under normal operating conditions,
The place where sludge is generated can be only the pressure flotation device 33.

As described above, the anaerobic filter bed 32, the pressurized flotation separator 33, and the aerobic filter 34 having the carrier floating section 13 are provided.
By performing anaerobic and aerobic treatment in combination with the above, efficient and efficient nitrogen removal can be performed even in a relatively small-scale wastewater treatment facility. In particular, by using the pressure flotation separator 33, the amount of suspended components of the treated water sent to the aerobic filter bed 34 can be reduced, and the treatment efficiency of the aerobic filter bed 34 can be improved. In addition, since the place where the excess sludge is generated can be unified into the pressure flotation / separation device 33, the treatment of the sludge becomes easy. Furthermore, by providing the air diffuser 32a to the anaerobic filter bed 32 and adjusting the anaerobic degree in the filter bed, anaerobic treatment can be performed reliably in a stable state.

The wastewater treatment apparatus according to the present invention is not limited to the one applied to the aerobic filter bed as in the above embodiments,
The present invention can be applied to a wastewater treatment under a microaerobic condition or an anaerobic condition, and the fungi to be retained on the carrier can be appropriately selected according to the treatment purpose. Further, the equipment configuration in the anaerobic / aerobic treatment is not limited to the above embodiment.

[0022]

As described above, according to the wastewater treatment apparatus of the present invention, a floating carrier is put into the upper part of a fixed bed for performing wastewater treatment in an aerobic state, a microaerobic state or an anaerobic state. Therefore, the treatment efficiency can be greatly improved, and it is possible to perform advanced treatment even in a small-scale sewage treatment facility.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing an example of an aerobic filter bed to which the present invention has been applied.

FIG. 2 is a system diagram showing an example in which the present invention is applied to an aerobic filter using an anaerobic filter method.

FIG. 3 is an explanatory view showing an example of a conventional aerobic filter bed.

[Explanation of symbols]

10: aerobic filter bed, 11: filter medium, 12: filter medium filling section, 1
3 ... Carrier floating part, 14 ... raw water inflow pipe, 15 ... wedge wire screen, 16 ... wash drainage pipe, 17 ... filter medium support layer, 18 ... compressor, 19 ... aeration pipe, 20 ...
Water collecting nozzle, 21: treated water discharge pipe, 30: raw water tank, 31
... Washing drainage tank, 32 ... Anaerobic filter bed, 33 ... Pressurized flotation separator, 34 ... Aerobic filter bed, 35 ... Treatment tank, 38 ... Sludge storage tank, A ... Floating carrier

Claims (4)

[Claims] 1. A fixed carrier is filled in a lower portion of a wastewater treatment tank,
A wastewater treatment apparatus, wherein a floating carrier is charged into water in an upper part of a tank above the fixed carrier. 2. A wastewater treatment wherein a lower part of a wastewater treatment tank for performing aerobic wastewater treatment is filled with a fixed carrier having a filtering function, and a floating carrier is introduced into water in an upper part of the tank above the fixed carrier. apparatus. 3. The wastewater treatment apparatus according to claim 2, wherein the wastewater treatment tank is an aerobic filter bed that performs wastewater treatment by an anaerobic aerobic filter method. 4. The wastewater treatment apparatus according to claim 2, wherein the floating carrier is a carrier entrapping and fixing nitrifying bacteria or a carrier to which nitrifying bacteria easily adhere.