JPH0824882A - Biological filtration device - Google Patents

Abstract

PURPOSE:To pass an ozone-treated water which is obtained by treating a waste water using ozone through a single filtration tank to decomposite the ozone and treat an organic substance biologically. CONSTITUTION:This biological filtration device is composed of a biological filtration tank 10 in which an ozone-treated water flows upward, and a lower activated carbon-packed layer 11, an upper floatable filter medium-packed layer 13 attaching microbes keeping a space 12 above the lower activated carbon-packed layer 11, and an aeration means 14 located below the lower activated carbon-packed layer, all these elements being provided in the biological filtration tank 10.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a biological filtration apparatus for treating sewage containing organic matter with ozone and biologically treating the ozone-treated water with microorganisms.

[0002]

It is well known in the art to treat sewage with ozone and biologically treat the ozonated water with biofiltration. In that case, the ozone remaining in the ozone-treated water comes into contact with the biofilm of the microorganisms adhering to the filter material for biological filtration, whereby the microorganisms are inhibited by the oxidative sterilization action of ozone, and sufficient biological treatment cannot be performed.

[0003]

For this reason, conventionally, a retention tank for ozone decomposition or an activated carbon filling tank is provided between the ozone treatment tank and the biological filtration tank to retain ozone remaining in the ozone-treated water. It is either self-decomposed in the storage tank, or the residual ozone is decomposed by the activated carbon in the activated carbon filling tank and then supplied to the biological filtration tank. Therefore, since a retention tank for ozone decomposition and an activated carbon filling tank are required, equipment costs increase and a large installation space is required.

[0004]

SUMMARY OF THE INVENTION The present invention was developed in view of the above, and is a biological filtration device for biologically filtering ozone-treated water obtained by treating wastewater with ozone in an upward flow. In the biological filtration tank that flows upward, a lower packing layer made of activated carbon, and an upper packing layer made of a buoyant filter medium having microorganisms attached at intervals above the lower packing layer,
An aeration means is provided below the lower packed bed.

[0005]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In the illustrated embodiment, 1 is an ozone treatment tank, in which an appropriate packing layer 2 is provided on the water surface in the tank, and sewage containing organic substances is sprayed on the packing layer 2 by a spraying pipe 3 to remove ozone. Blow by the air supply pipe 4 into the bottom of the tank. As a result, the sewage flowing downward in the packed bed 2 comes into countercurrent contact with ozone flowing upward in the packed bed, and is oxidized and sterilized by the ozone. The ozone-treated water passes through the pump pit 6 and the pump, and the biological filtration tank 1
0 is supplied to the bottom of the tank. Excess ozone escapes from the exhaust port 5 on the upper wall of the ozone treatment tank.

Biological filtration tank 10 in which ozone-treated water flows upward
Inside, the lower packing layer 11 made of activated carbon, the upper packing layer 13 made of a buoyant filter medium having microorganisms adhered to the lower packing layer at intervals 12 and the diffusing pipe 14 as an aeration means under the lower packing layer. And are provided. The activated carbon of the lower packed bed 11 is, for example, Kuraray Coal 2GG (2.0 mmφ × 3.0 mmL) manufactured by Kuraray Chemical Co., Ltd., and the activated sludge treated water is continuously passed in advance to obtain the COD adsorption capacity of the activated carbon body. Use saturated ones. Further, spherical styrofoam particles (specific gravity 0.03 to 0.08) having an average particle diameter of about 3 mm are used as the floating filter material of the upper filling layer 13. A water-permeable water collecting plate 15 having a mesh size smaller than that of the floating filter medium is provided on the upper surface of the upper filling layer 13 to prevent the filter medium from flowing out.

During operation, air is supplied to the air diffuser 14 to cause air bubbles to float in the filtration tank, and oxygen is supplied to the microorganisms adhering to the upper packed bed 13. As a result, the ozone-treated water supplied to the bottom of the filtration tank and flowing upward in the tank efficiently decomposes the ozone dissolved in the lower packed bed 11 by the activated carbon. Then, the upper filling layer 13 made of the floating filter material
When flowing upward, the organic matter contained in the filter medium is biologically decomposed by the biofilm of microorganisms attached to the filter medium, and treated water containing no organic matter is discharged from the drain pipe 16.

Actually, the diameter is 400 mm and the height is 3500.
In a biological filtration tank of mm, a layer height of 2.0 is obtained by using spherical styrofoam (specific gravity 0.03 to 0.05) having an average particle diameter of 3 mm.
m top packed bed and activated carbon (diameter 2 mm, length 3 above)
mm lower layer with a bed height of 0.8 m. Then, as a preparatory operation for producing a biofilm on the levitation filter medium and for almost saturating the COD adsorption capacity of the activated carbon, air was passed from the air diffuser to LV = 10.
The activated sludge treated water of the general waste water of the food processing factory was supplied to the tank bottom while being diffused at m / hour, and water was passed for one week in an upward flow of LV = 20 m / hour. Meanwhile, during that time, cleaning air (LV = 50 m / hr) is blown from the air diffuser, backwash water is supplied to the upper packed bed from above, and backwash drainage is drained from the space between the upper and lower packed beds. The process was performed once per day.

The same activated sludge treated water was supplied to the ozone treatment tank, and the ozone treated water was treated at an ozone injection amount of 30 mg / vertical (0.6 to 2.2 mg of O ₃ / vertical ozone remains).
Was supplied to the bottom of the biological treatment tank, and the biological treatment was carried out by upward flow at LV = 20 m / hour. Stable treatment could be performed for 1.5 consecutive months (see Fig. 2). ). In the backwash, as described above, the backwash water is sprayed on the upper packed bed 13 by the sprinkling pipe 17, the backwash air is sparged from the air diffusing tube 14, and the backwash wastewater is separated from the space between the upper and lower packed beds. The water is drained from the pipe 12 through the pipe 18. The air diffuser 14 serves both to supply oxygen to the microorganisms adhering to the floatable filter medium of the upper packing layer and to supply air for backwashing, and the space 12 between the upper and lower packing layers serves for draining backwashing drainage.

[0010]

As is clear from the above, according to the present invention, since the lower packing layer of activated carbon is provided below the upper packing layer for biological treatment by the floatable filter medium in the biological filtration tank,
When ozone-treated water containing residual ozone is allowed to flow upward into the tank, activated carbon in the lower packed bed effectively decomposes ozone. Therefore, the microorganisms adhering to the floating filter material of the upper packing layer can biologically decompose organic matter in water without being inhibited by ozone. Further, since it is not necessary to separately install a stagnant tank for ozone decomposition and an activated carbon packed bed, equipment cost does not increase and space can be saved.

[Brief description of drawings]

FIG. 1 is a flow sheet of an embodiment of the present invention.

FIG. 2 is a graph of processing status.

[Explanation of symbols]

 1 Ozone Treatment Tank 2 Filled Bed 3 Dispersion Pipe 4 Air Supply Pipe 5 Exhaust Port 6 Pump Pit 10 Ozone Treatment Layer 11 Lower Filled Layer with Activated Carbon 12 Interval 13 Upper Filled Layer with Floating Filter Media 14 Diffuser Pipe (Aeration Means) 15 Water Collection Plate 16 Drain pipe 17 Backwash water sprinkling pipe 18 Backwash drainage pipe

Claims (1)

[Claims] 1. A biological filtration device for biologically filtering ozone-treated water obtained by treating wastewater with ozone in an upward flow,
In a biological filtration tank in which ozonated water flows upward, a lower packed bed of activated carbon, an upper packed bed of buoyant filter media with microorganisms attached at intervals above the lower packed bed, and a lower packed bed of the lower packed bed. A biological filtration device characterized in that an aeration means is provided in the.