JPS60197295A - "tater-bed" biological treatment apparatus - Google Patents

Abstract

PURPOSE:To enhance purification efficiency, by packing a porous inorg. substance, of which the density is 0.4-1.0g/cm<3> and the particle size is 3-15mm. as a carrier so that the ratio of the static layer volume of the carrier to a ''tater- bed'' is adjusted to 20-80vol%. CONSTITUTION:An upper screen 2a and a lower screen 2b each having a mesh width smaller than the particle size of a carrier are provided in a treating tower or tank 1 in two upper and lower stages. Sewage is introduced from the pipe 5 below the lower screen 2b and air is blown into the sewage through a porous air diffusion disc 4. Oxygen required in sustaining existing microorganisms is supplied by the aeration from the air diffusion disc 4 and the up-and-down fluidization of the carrier is performed. Further, microorganism flocs released from the carrier by sludging due to rising air bubbles in the lower part of the upper screen 2a are added to said upper screen 2a to prevent the clogging thereof. Purified treated water is discharged along with flocs from a drain pipe 6 above the upper screen 2a.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a teeter-bed type fluidized bed biological treatment apparatus using an inorganic carrier having a particle size of several I.

A foam made of a hydrophobic polymer compound has been proposed as a carrier for use in a fluidized bed biological treatment system for water. Sufficient purification efficiency cannot be obtained.

On the other hand, inorganic substances such as sand, crushed gravel, and activated carbon have excellent adhesion properties for microbial films, but their high specific gravity requires large amounts of power to fluidize them, so they are used as fixed beds rather than as biological treatment equipment. It is used as a device or adsorption device.

Furthermore, even if these inorganic substances are made into microscopic carriers that are easily fluidized, during the wastewater treatment process, microbial membranes 77 enlarge, resulting in changes in particle size and specific gravity, and further, membrane fusion between carriers occurs. easy.

The purpose of the present invention is to improve the purification efficiency by improving the contact between aerobic or anaerobic microorganisms living on the surface of the phase in a Teeta-Bet type fluidized bed and wastewater, and to improve the purification efficiency. The attached microbial film is peeled off by the collision and friction between the carriers, and the excess microbial flocs are suspended in purified water and automatically flowed out of the Teeta fist bed.

Therefore, the present invention has a density of 0.4 to 1.0 g/c and a grain size of 3 to 3.
The present invention provides a biological treatment device in which the ratio of the static layer volume of a 15 m+w porous inorganic carrier to the teeter bed is 20 to 80%.

By making the carrier into coarse particles of several microorganisms or more, ■ changes in particle size, changes in specific gravity, particle-fusion, etc. due to microbial adhesion during the treatment process are smaller than those of fine powder, <k
+Collision and friction between microbial film-attached carriers is greater than that of fine powder, making it easier to prevent the Jj1 body from enlarging; ・31 Since the difference in particle size between the detached microbial floc and the pressed body is large, the floc can be removed from within the bed. It has the advantage of being easy to exclude.

On the other hand, the possible drawbacks are (l, low fluidity, c) the surface area of the carrier may be relatively small; This problem can be solved by using spherical light aggregate molded from shale or the like.

In the present invention, a carrier having a specific gravity in the range of 0.4 to 1 before absorbing water is used so that the specific gravity in the state of absorbing water is slightly greater than 1.

In addition, for missing j:''・2,・, by filling the stationary layer volume ratio of the pushing body in the range of 20 to 80% (volume) for the teeter competition bet, 1 of the normal fixed bed processing equipment. Close-packed collapse on the floor! A surface area greater than 11 is obtained.

For example, in the case of a pressed particle size of 3 cm, the surface area of the carrier when the filter bed is most closely packed is about 735 m'/m', so when the static layer volume ratio is in the range of 20 to 80%, it is 147 to 588 m'/rn'.
This results in a surface area that is approximately twice as large as the 70 to 200 m'/m'' surface area of a normal fixed-bed biological treatment apparatus in its closest packed state.

In addition, the lower limit of 20% of the filling range of Tamaki in the present invention is the limit at which at least the surface area of the conventional fixed bed filter bed can be obtained even when the particle size of the carrier is the lower limit of 3 mm. n. The number of microorganisms that can be formed is reduced, resulting in a decrease in purification efficiency.

In addition, the limit value of 80% is the limit at which the carriers in the filter bed can undergo Teeter-type flow, and beyond this point, collisions between the carriers decrease, the enlargement of microorganisms 11!2 progresses, and the formation of flocs. Difficult to drain.

To explain the device according to the embodiment of the present invention with respect to 1st U; 4,
(1) is a treatment tower or tank, and is provided with an L portion screen (2a) and a lower screen (2b) having a mesh size smaller than the particle size of the pressed body in two stages. (3) is 714 units and is filled with a predetermined amount of acid in the volume range mentioned above. Sewage is introduced (5) from below the lower screen (2b) and air is blown through the porous diffuser (4). Aeration from the aeration plate supplies oxygen necessary for the resident microorganisms, and also causes the carrier to flow 1° above the carrier.

Further, on the lower surface of the two-part screen (2a), sludging by rising air bubbles prevents microbial flocs separated from the carrier from adhering to the screen and becoming a single product.

The purified water is drained from the drain pipe (6) on the L side from the partial screen.
) to the flock and 1().

In the device shown in Figure 2, a screen (2c) is placed on the water surface (Q) and stretched over the overflow port of the tank wall, and the 714 bodies are stirred and flowed by the gas-liquid mixed flow from the underwater parachelator (7). be converted into

In this device, the carrier applies centrifugal force to the water in the tank and also brings in air by coming into contact with the outside air.

When applying each of the above devices to anaerobic microorganisms, nitrogen gas or the like may be introduced instead of air, or mixing and contact may be carried out using a stirrer in a closed tank.

[Brief explanation of drawings]

Figure 1: Figure 52 is a sectional view of an embodiment of the Ooki invention.

Claims (1)

[Claims] Density 0.4-1.0g/cm", particle size 3-15+amc
7) A Teeter Bed biological treatment device, characterized in that a porous inorganic material is used as a carrier, and the carrier is filled so that the volume ratio of the 10 static layers to the Teeter Bed is 20 to 80% (volume 1).