JP2002153894A - Water treatment equipment of fluidized bed type - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide water treatment equipment which improves the cleaning ability of filter media for a fluidized bed. SOLUTION: This equipment is provided with an inclined resistance board 24 for preventing the stagnation of the filter media which inclines toward a water surface side from a chamber wall 20 segment where descending flow 12a arises in the upper part of a filter chamber 2, by which the filter media 5 are prevented from heading toward the stagnating segment near the wall of the filter chamber, the filter media 5 are continuously suspended in the circulating water flow of sewage and the cleaning ability is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluidized bed water treatment apparatus for purifying water such as sewage and wastewater.

[0002]

2. Description of the Related Art As a water treatment apparatus, a fixed bed type in which a filter medium such as quarry or plastic for adhering and growing microorganisms is fixed to a filter tank, and a fluid bed type in which a filter medium is installed in a floating state by adhering and growing microorganisms. But recently, BO
A fluidized bed type capable of continuously maintaining a purification capacity against a D (biochemical oxygen demand) load has been attracting attention.

In a fluidized-bed water treatment apparatus, a large number of small-diameter sponge-like or cylindrical filter media are suspended in sewage in a filtration tank, and air is sent from a lower part of the filtration tank by an air ejection pipe of an aeration device to remove the sewage. While circulating, sewage is filtered using the purification capacity of the filter medium.

[0004]

By the way, the present inventor tried various experiments on a fluidized-bed type water treatment apparatus exhibiting an efficient purifying action. In the circulation path, the floating filter medium stays at the tank wall at the conversion point where the horizontal water flow at the top of the filter tank changes to a downward water flow, the filter medium circulating with the sewage gradually decreases, and the purification ability by the filter medium decreases. I found it to go.

It is considered that this retention phenomenon of the filter medium is caused by the phenomenon of water retention or vortex generation occurring at the collision point between the circulating water flow and the tank wall of the filtration tank, and the floating filter medium accumulating at that location. .

[0006]

Accordingly, the present inventor has conducted intensive studies to improve and maintain the purification capacity of the fluidized bed filter medium. As a result, the present inventor has found that a downward flow of water is generated at the upper part of the filter tank. A configuration in which an inclined resistance plate for preventing filter medium stagnation that inclines toward the water surface side is provided, or a configuration in which an ascending regulation network that regulates the rise of the filter medium below the upper water surface of the filter tank is provided,
Furthermore, it has been found that if a configuration in which the inclined resistance plate and the elevation control net are used together is employed, the filter medium can continue to float in the circulating water stream of the sewage without going to the above-mentioned stagnation portion, and the purification ability can be improved and maintained. Was.

If the inclined resistance plate is arranged, the filter medium carried by the circulating water flow collides with the inclined resistance plate, flows downward with the circulating water flow, and accompanies the circulating water flow. Therefore, it is possible to suppress the reduction of the filter medium in the circulating water flow without the filter medium going to the stagnation site.

It is not necessary to dispose the inclined resistance plate around the entire circumference of the filtration tank, and it is sufficient to adopt a configuration in which the inclined resistance plate is disposed at least at a point where the circulating water flow is converted from horizontal to downward below the water surface. In other words, the direction of the circulating water flow generated in the filtration tank,
In other words, it is determined by the air ejection direction of the air ejection pipe of the aeration device that generates the circulating water flow.

[0009] For example, when the air ejection portion of the air ejection pipe is located at the center of the bottom of the filtration tank, the upward flow of the circulating water flow is at the center of the filtration tank, and the point where the horizontal water flow is converted to the downward water flow is around the filtration tank. become. In this case, it is necessary to arrange an inclined resistance plate all around the filtration tank. In addition, when the air is ejected from one side of the bottom of the filtration tank, the upward flow of the circulating water flow is generated along the tank wall on one side of the filtration tank, and the point where the water flow is converted from the horizontal direction to the downward flow is the other point of the filtration tank. Since it becomes a side tank wall part, the structure which installs a slope resistance board in that part is preferred.

The height of the inclined resistance plate may be set so as to reach the upper surface of the filtration tank and reach the water surface. For example, it is preferable to project from the water surface downward by about 100 mm to 300 mm, and to project toward the center of the filtration tank by about 100 mm to 300 mm. The inclination angle of the inclination resistance plate is 30 degrees to 60 degrees.
Degrees, preferably about 45 degrees. The shape of the inclined resistance plate may be any of a flat plate shape and a curved shape adapted to a circulating water flow. Further, the inclined resistance plate may have any of a solid structure and a mesh structure with holes.

The shape of the filtration tank may be a rectangular parallelepiped shape or a cylindrical shape, and the filter medium retention portion is determined according to each shape and the installation position of the air ejection pipe. A board may be installed.

Next, a configuration in which a rise control network is installed will be described. The rise control network has a role of permitting the circulation of sewage and suppressing the rise of the filter medium. The ascending filter medium riding on the upward flow of the circulating water flow is caused to collide with the upward regulation net, and is carried to the bottom side of the filter tank by the downward force of the downward flow of the circulating water flow. Is to be circulated. Therefore, the concept of the rising regulation net includes not only a simple net-like structure but also a form in which a plurality of holes are formed in a plate material in a scattered manner.

[0013] The height position of the elevation control network is preferably the upper position of the filter tank because the longer the circulation path of the filter medium, the better the filter medium exhibits a good purification ability. It is preferable to install it below the site. Further, when used in combination with the inclined resistance plate, it is disposed below the inclined resistance plate.

[0014] The rising regulation network is formed in such a manner that it is installed substantially horizontally in the filtration tank, but the extension area does not need to be the whole area of the filtration tank. This is because when the ejection pressure of the air ejected from the air ejection pipe of the aeration apparatus is large, the filter medium does not enter the upward flow and is transported upward. Therefore, when the air ejection pressure is high, the air jetting pressure may be extended to a portion other than the portion where the upward flow is generated. For example, when the air ejection pipe is arranged on one side of the bottom of the filtration tank, the elevation control net may be extended in an area of about 80% excluding the area above.

[0015] The mesh of the elevation regulating net may be of a size that can prevent passage of the filter medium. Since the size of the filter medium used as a fluidized bed filter medium is approximately 3 mm to 40 mm, a mesh having a diameter (or square) of 2 mm to 30 mm may be used in accordance with the size.

As described above, by providing the filter tank with the inclined resistance plate or the elevation regulating net, the filter medium does not go to the stagnation area near the water surface of the filter tank, and continues to float in the circulating water flow of the sewage. Purification ability can be improved and maintained.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [First Embodiment] An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic perspective view of a water treatment apparatus according to the first embodiment, FIG. 2 is a schematic cross-sectional view of a filtration tank, and FIG. 3 is a schematic view showing a filter medium retaining portion of the filtration tank.

As shown in the figure, the water treatment apparatus 1 of the present embodiment
Is a filter tank 2 for inflowing and filtering sewage, an inflow pipe 3 for inflowing sewage into the filtration tank 2, a drain pipe 4 for discharging purified water, and a filter medium 5 suspended in water, thereby forcing sewage. And an aeration device 6 for circulating the water.

The filtration tank 2 is a rectangular parallelepiped tank having a volume capable of storing sewage, an outlet of the inflow pipe 3 is disposed at an upper opening thereof, and a drainage water is disposed at an intermediate position in the height direction of the tank wall. Tube 4 is connected.

The aeration device 6 includes an air ejection pipe 10 installed at a lower part of the filtration tank, and a blower 11 for sending air to the air ejection pipe 10. The air outlet 10 a of the air outlet pipe 10 is arranged on one side of the bottom of the filtration tank 2,
The air is blown upward.

The sewage in the filtration tank 2 forms a circulating water flow 12 by the ejection of air from the air ejection pipe 10. The circulating water flow 12 includes an upward flow 12a flowing upward from the air outlet 10a, an upper horizontal water flow 12b that flows sideways after the upward flow 12a reaches near the water surface (WL),
The downward flow 12c in which the horizontal water flow 12b hits the other side wall 20 of the filtration tank 2 and flows downward, and the downward flow 12c
Lower side flow 1 which hits the bottom 21 of the
2d and an inner upward flow 12e that converts upward from the lower lateral flow 12d along with the upward flow 12a near the outlet 12a, and these water flows are continuously circulated.

At this time, as shown in FIG. 3, the water and the floating filter medium 5 stay at the collision portion between the circulating water flow 12 and the tank wall 20 of the filtration tank 2, that is, the collision portion between the upper horizontal water flow 12b and the tank wall 20. A stagnation site 13 results. Symbols A, B, and C shown in FIG. 3 represent the process in which the floating filter media 5 are sequentially accumulated and accumulated.
Accumulation phenomenon occurs.

In the present embodiment, in order to prevent the stagnation phenomenon of the filter medium 5, the upper part of the filter tank 2 is directed from the other side tank wall 20 of the filter tank 2 where the downward downward rain flow 12 c occurs to the water surface WL side. An inclined resistance plate 24 for preventing the filter medium from staying is provided to prevent the filter medium 5 from staying.

The inclined resistance plate 24 is a solid flat plate as shown in FIG. 2, and its upper and lower ends are bent, the lower end bent portion 24a is fixed to the other tank wall 20, and the upper end bent portion is formed. 2
4b protrudes above the water surface WL.
The height of the inclined resistance plate 24 is 100 mm to 300 mm below the water surface.
mm, and the width of the protrusion toward the center of the excess tank at the inner end is set to about 100 mm to 300 mm, and as a result, it is installed at an inclination angle of about 45 degrees as a whole.

The filter medium 5 for a fluidized bed is a honeycomb structure or a pipe-shaped member made of foamed plastic having a specific gravity of about 0.98, and adheres and proliferates microorganisms on the surface, thereby removing the biofilm and sewage on the surface. By contacting it, it captures and decomposes organic matter in sewage.
Various shapes can be selected from about mm to about 20 to 30 mm. Further, a structure may be employed in which the surface of the filter medium 5 is roughened to further enhance the purification ability.

In the above configuration, if the inclined resistance plate 24 is arranged so as to block the filter medium retaining portion 13 near the water surface of the filter tank 2, the filter medium 5 carried by the circulating water flow 12 collides with the resistance plate 24 and Since the filter medium 5 flows downward together with the circulating water stream 12 and accompanies the circulating water stream 12, the filter medium 5 does not go to the stagnation site, so that the reduction of the filter medium 5 in the circulating water stream can be suppressed and the purification ability can be improved and maintained.

[Second Embodiment] FIG. 4 is a schematic diagram of a filtration tank of a water treatment apparatus showing a second embodiment. The filtration tank 2 of the present embodiment is the same as the tilt resistance plate 2 of the first embodiment.
Instead of the filter 4, an ascent network 25 that regulates the ascent of the filter medium 5 is provided below the upper surface of the filter tank 2.

The rising regulation network 25 allows the circulation of sewage,
It is for suppressing the rise of the filter medium 5, and is used for circulating water flow 1
The filter medium 5 ascending on the ascending flows 12a and 12e of FIG.
Is carried to the bottom 21 side of the filtration tank 2 by the downward force, and the filter medium 5 is circulated between the bottom 21 of the filtration tank 2 and the elevation regulating net 25.

The height of the elevation control net 25 is extended almost horizontally at a position directly below the stagnation portion 13 above the filtration tank 2. The area may be stretched with an area of about 80% excluding the area above the mouth 10a, but a mode in which the area is stretched over the entire surface may be adopted.
The mesh of the rising regulation net 25 can prevent the passage of the filter medium 5 2
A mesh having a diameter (or a corner) of 30 mm to 30 mm is used. The other configuration is the same as that of the first embodiment, and a description thereof will be omitted.

In the above configuration, the filter medium 5 is
Circulates between the bottom portion 21 and the elevation control net 25, and the filter medium 5 does not go to the stagnation portion 13 near the water surface WL but continues to float in the circulating water flow of the sewage.
The purification ability can be improved and maintained.

[0031]

As is apparent from the above description, according to the present invention, by providing the filter tank with an inclined resistance plate or a rise control net, the filter medium does not go to the stagnation portion near the water surface of the tank wall, but continuously. Since the wastewater can be suspended in the circulating water stream, the purification capacity of the fluidized bed filter medium can be improved and maintained.

[Brief description of the drawings]

FIG. 1 is a schematic perspective view of a water treatment device according to a first embodiment.

FIG. 2 is a schematic sectional view of a filtration tank.

FIG. 3 is a schematic diagram showing a filter medium retaining portion of a filtration tank.

FIG. 4 is a schematic diagram of a filtration tank of a water treatment apparatus showing a second embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Water treatment apparatus 2 Filtration tank 3 Inflow pipe 4 Drain pipe 5 Filter medium 6 Aeration apparatus 10 Air ejection pipe 13 Retention part 20 Tank wall 21 Bottom part 24 Inclined resistance plate 25 Ascending regulation network

Claims (3)

[Claims] 1. A fluidized bed water from which a sewage in a filtration tank is circulated from the lower part of the filtration tank by an air ejection pipe of an aeration device, and the sewage is filtered by a purification capacity of a fluidized bed filter medium floating in the sewage in the filtration tank. A fluidized-bed water treatment apparatus, comprising: a treatment device provided with an inclined resistance plate for preventing stagnation of a filter medium, which is inclined from a tank wall portion where a downward water flow is generated at an upper portion of the filtration tank toward a water surface side. 2. A fluidized bed water from which a sewage in a filtration tank is circulated from the lower part of the filtration tank by an air jet pipe of an aeration device, and the sewage is filtered by a purification capacity of a fluidized bed filter medium floating in the sewage in the filtration tank. In the treatment apparatus, a fluidized bed type water treatment apparatus is provided with a rise regulation network for regulating rise of a filter medium below an upper surface of the filter tank. 3. The fluidized bed type water treatment apparatus according to claim 1, wherein a flow regulating network is provided below the upper surface of the filter tank and below the inclined resistance plate to regulate the rise of the filter medium. Floor type water treatment equipment.