JPH10202281A - Waste water treating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely and efficiently execute a solid-liq. separation of a treated water of a fluidized bed and to make the whole device compact by providing a pressure floatation device executing a solid-liq. separation treatment of the treated water at a post stage of the fluidized bed in a treatment of sewerage with the fluidized bed using a biological membrane sticking carrier. SOLUTION: A raw water made to flow into a raw water tank 15 is raised in the fluidized bed 11 and subjected to an aerobic purifying treatment with microorganisms stuck on a biological membrane-sticking carrier, then sent to the pressure floatation device 12. In the pressure floatation device 12, a pressurized air- dissolving water is mixed to the treated water of a fluidized bed, and a suspension component is floated by making its apparent density small by sticking a suspension component in the treated water of the fluidized bed to finely divided bubbles generated from the pressurized air-dissolving water, and the floated sludge is scraped with a scraper and sent to a sludge storage tank 24, and precipitated sludge is sent to a sludge storage tank 24. Then the treated water executed some order solid-liq. separation is subjected to a main finishing treatment at a filter tank 13, and the water subjected to the filtering treatment is discharged to a river, etc., through a treated water tank 31.

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 fluidized bed wastewater treatment apparatus for treating wastewater by a fluidized bed using a biofilm-adhered carrier.

[0002]

2. Description of the Related Art A wastewater treatment method using a fluidized bed has a high treatment efficiency because a large amount of organisms are retained and a high stirring force can be obtained, and it is possible to perform sufficient wastewater treatment with a compact apparatus. . For this reason, many studies have been made so far, but there are practical examples in small-scale facilities in industrial wastewater treatment, but few practical examples in relatively large-scale such as public sewage treatment.

In addition, since the solid-liquid separation is not performed in principle in the fluidized bed itself, it is necessary to combine another solid-liquid separation device. Since the sedimentation basin and the filtration device of the formula were used as they were, the performance of the fluidized bed could not be sufficiently exhibited.

[0004]

When a gravity sedimentation basin is used for solid-liquid separation treatment as a solid-liquid separation device for treated water in a fluidized bed, the installation area of the sedimentation basin is large, so that the entire equipment is made compact. Was not enough. That is, when the drainage treatment is performed by the fluidized bed, the water passage speed can be increased to 600 to 800 m / day, but the water passage speed of the gravity type sedimentation pond is generally 20 to 100 m / day. A sedimentation basin with a large area for the floor throughput must be installed.

[0005] On the other hand, the fluidized bed can be operated at a high load, but when the load is high, the amount of suspended components flowing out of the fluidized bed increases. When a filtration device was used, it was difficult to stably continue the filtration operation for a long time.

Accordingly, the present invention provides a wastewater treatment which can surely and efficiently perform solid-liquid separation of treated water in a fluidized bed, makes full use of the advantages of a fluidized bed, and makes the entire facility compact. It is intended to provide a device.

[0007]

In order to achieve the above object, a wastewater treatment apparatus according to the present invention is a wastewater treatment apparatus for treating wastewater by a fluidized bed using a biofilm-adhered carrier. Further comprising a pressurized flotation device for performing a solid-liquid separation treatment of the treated water treated in the fluidized bed. It is characterized by having a filtration tank for filtering the treated water.

[0008]

FIG. 1 shows an example of a wastewater treatment facility using a wastewater treatment apparatus according to the present invention. The solid-liquid separation of treated water treated by a fluidized bed 11 is performed by pressure flotation separation. This is configured to be performed by a combination of the device 12 and the filtration tank 13.

After the inflow sewage (raw water) flows into the raw water tank 15 through the screen 14, it is sent to the bottom of the fluidized bed 11 by the pump 16 and rises in the fluidized bed 11 together with the air supplied from the compressor 17. Then, an aerobic purification treatment is performed by microorganisms adhering to the biofilm-adhering carrier 18.

As the biofilm-adhering carrier 18, conventionally used carriers such as anthracite and granular activated carbon can be used. However, inorganic materials such as silica and calcium for adjusting the specific gravity, and polypropylene and polyethylene can be used.
It is preferable to use a plastic carrier to which metal powder is added. The specific gravity of such a plastic carrier can be arbitrarily adjusted by adjusting the amount of the silica or the like added thereto. And the optimum range can be set according to the processing conditions.

Further, the size of the biofilm-adhering carrier 18 is relatively large, for example, 2 to 20 m, depending on the specific gravity and the surface area.
By setting it to about m, the separation property from the treated water and the cleaning property can be improved. Therefore, the biofilm-adhered carrier 1 having a specific gravity and a size corresponding to the amount of inflowing raw water into the fluidized bed 11
Since it is possible to use No. 8, it is possible to set the holding amount of the living organisms and the stirring power in an optimum state, and it is possible to greatly improve the processing efficiency. The biofilm-adhering carrier 18
Any shape can be used as long as it can be molded, such as a sphere or a pipe, but it is preferable that its surface has fine irregularities to which a biofilm can easily adhere. Further, those having pores of about 50 to 300 μm suitable for the inhabitation of microorganisms are particularly preferable.

The treated water (fluidized bed treated water) treated in the fluidized bed 11 is separated from the biofilm-attached carrier 18 by a wedge wire screen 19 provided at the upper part of the bed, and is separated from the pipe 20 by a pressure flotation device. 12 is sent. The wedge wire screen 19 is formed, for example, by holding a large number of wedge-shaped wires formed in a ring shape at predetermined intervals by a plurality of support rods, closing both ends to form a drum shape, and forming the processing By connecting the pipe 20 for water outflow, by appropriately setting the interval between the wedge-shaped wires, it is possible to efficiently discharge treated water and sludge while suppressing clogging, Outflow can be reliably prevented. Therefore, by using the wedge wire screen 19 for separating the biofilm-adhered carrier 18, it is not necessary to increase the water area on the upper part or to provide a gas separating means accompanying aeration as in a conventional fluidized bed. The fluidized bed 11 can be simplified and made compact.

The pressurized flotation device 12 mixes the fluidized bed treated water supplied from the pipe 20 with the pressurized air dissolved water supplied from the pipe 21, and converts the fine bubbles generated from the pressurized air dissolved water into fine bubbles. The floating components are floated by adhering suspended components in the fluidized-bed treated water to reduce the apparent specific gravity, and the raised floating sludge (floss) is scraped by the scraper 22 and passed through the path 23 to the sludge storage tank. The sludge which has been sent to the bottom 24 and settled at the bottom is sent from the passage 25 to the sludge storage tank 24. The sludge concentration at this time is 3 to 5%, which is higher than gravity concentration in a conventional sludge concentration tank.

A part of the water treated by the pressurized flotation device 12 is withdrawn from a pipe 26 at an outlet side, pressurized by a pump 27, and mixed with compressed air supplied from a compressor 28 in a mixing tank 29. After that, it is supplied to the fluidized-bed treated water from the pipe 21 and mixed as pressurized air-dissolved water.

The treated water (pressurized levitation treated water) that has been subjected to a certain degree of solid-liquid separation processing by the pressure flotation / separation apparatus 12 is
It flows into the bottom of the filtration tank 13 from the pipe 30 and mainly
Finishing treatment is performed by removing components, and the filtered water is discharged to a river or the like via a treated water tank 31. In addition,
In the filtration tank 13, a drawing pipe 32, an empty washing pipe 33, and a washing pipe 34 are provided in the lower part of the tank as washing means for washing the filter medium. Will be returned. In this way, the washing wastewater from the filtration tank 13 is returned to the raw water tank 15, mixed with the raw water, and treated again, so that the sludge generation site can be located in the pressure flotation device 1
In addition to being able to unify the wastewater into a single wastewater treatment facility, it is possible to increase the concentration of the generated sludge. It can be greatly reduced.

Further, the pressure flotation device 12 can not only perform high-speed processing, but also has a higher removal rate of suspended components than ordinary gravity sedimentation processing. It is not necessary to install 13, and it is possible to perform a sufficient solid-liquid separation process only by the pressure flotation device 12. Further, when the filtration tank 13 is provided at the subsequent stage of the pressure flotation device 12, the load on the filtration tank 13 can be reduced, so that the capacity of the filtration tank 13 can be reduced. In the treatment, components that easily float, such as hair, oil, and scum, can be almost completely removed, so that clogging and scum in the filtration tank 13 are reduced, and continuous operation for a long time in a stable state is achieved. It becomes possible.

Therefore, by combining the fluidized bed 11 and the pressure flotation device 12, the treatment efficiency of the wastewater treatment equipment can be greatly improved, and the equipment can be downsized. Further, by adding the filtration tank 13, the quality of the treated water can be greatly improved.

In the above embodiment, the fluidized bed is an aerobic fluidized bed. However, it may be an anaerobic fluidized bed, and a non-chemical injection pressurized floater is used as a pressurized floater. However, it is also possible to adopt a coagulation pressure levitation to which a coagulant is added. Further, although the filtration tank has an upward flow, it may have a downward flow. The filter medium composition of the filtration tank may be a multilayer type, and the type of the filter medium may be anthracite, silica sand, another plastic filter medium, or the like, and is not particularly limited.

[0019]

As described above, the wastewater treatment apparatus of the present invention combines a fluidized bed with excellent treatment efficiency and a pressurized flotation apparatus with a high removal rate of suspended components, thereby increasing the treatment capacity. The size of the equipment can be reduced without any loss.

[Brief description of the drawings]

FIG. 1 is a system diagram showing an example of a wastewater treatment facility using a wastewater treatment device of the present invention.

[Explanation of symbols]

11: Fluidized bed, 12: Pressure flotation separator, 13: Filtration tank, 15: Raw water tank, 18: Biofilm adhered carrier, 19: Wedge wire screen, 22: Scraper, 24: Sludge storage tank, 29 ... Mixing tank, 31 ... treated water tank

Claims (2)

[Claims] 1. A wastewater treatment apparatus for treating sewage wastewater by a fluidized bed using a biofilm-adhered carrier, wherein a pressurization for performing a solid-liquid separation treatment of the treated water treated by the fluidized bed is provided at a subsequent stage of the fluidized bed. A wastewater treatment device comprising a flotation device. 2. The wastewater treatment apparatus according to claim 1, wherein a filtration tank for filtering the treated water treated by the pressure flotation apparatus is provided downstream of the pressure flotation apparatus.