JPH11104681A - Organism immobilizing carrier for water treatment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a high yield continuously by a method ion which a cross section consists of a cross-shaped hollow cylinder, each cross-shaped corner gives roundness, an organism layer is formed in the cylinder, fluid moves in the layer, and organisms stripped from the cylinder is discharged outside the cylinder. SOLUTION: An organism immobilizing carrier 1 for water treatment is a a hollow cylinder with a cross-shaped cross section in which the long diameter of a carrier cross section 2 is 15 mm or below, the thickness of a carrier wall surface is 0.2-0.8 mm, the length of a carrier side part 3 is 7-15 mm and which is made from a plastic or a mixed material of a plastic and an inorganic material of 0.95-0.99 specific gravity, each crossed corner 2-1, 2-2, 2-3, 2-4 and at least one of the joint parts of corners are rounded, and an organism layer 4 of sludge and others is allowed to adhere to an inner wall and an outer wall surface. The organism immobilizing carrier meanders while being rotated by the change in water velocity due to aeration and an agitator in fluidized bed type water treatment. A flow is generated even inside the cylinder to activate the organisms inside the cylinder and stripped sludge is discharged outside the cylinder.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a biologically fixed carrier for water treatment, and by using the carrier, various kinds of wastewater treatment can be performed very efficiently in accordance with a biological method such as an activated sludge method. Water treatment can be performed.

[0002]

2. Description of the Related Art In a fluidized bed type water treatment, a biologically fixed carrier is used, and the water treatment is carried out while the carrier is flowing by aeration or a circulating flow by a stirrer. Small cylindrical supports are used.

[0003]

Conventionally, a cylindrical carrier has been used, but it is preferable that the size of the carrier is small in order to increase the processing efficiency. However, such a cylindrical carrier does not show remarkable biological growth inside, and also, during use, a biological layer such as sludge formed on the inner wall of the cylinder peels off and stays in the cylinder without flowing out, resulting in clogging. Will cause. As a result, a reduction in processing efficiency is inevitable.

[0004]

SUMMARY OF THE INVENTION In view of the above-mentioned prior art, and in view of the importance of wastewater treatment which has recently been increasing, the present invention efficiently treats various wastewaters without causing clogging or the like. It has been made for the purpose of developing a new carrier which can be used.

In order to achieve the above object, the present inventors have conducted studies from various fields and obtained the following findings. Bacteria and other microorganisms that adhere and grow on the inner and outer surfaces of the cylindrical carrier have a growth rate that is 2-3 times faster on the inner surface than on the outer surface. However, when the thickness of the biological layer is 200 μ or more, the penetration of oxygen does not reach, and as a result, the back surface (the carrier-attached surface) becomes anaerobic, and the biological layer peels off. And
In the case of a cylindrical carrier having an inner diameter of 3 mm or less, it was confirmed that microorganisms such as exfoliated sludge could not flow out of the cylinder and stayed inside the cylinder, resulting in clogging.

On the other hand, in order to promote biological growth on the inner surface of the cylindrical body, it is necessary to generate an appropriate flow of liquid inside the cylindrical body, and a separated biological layer such as separated sludge is required. It was also confirmed that a liquid flow inside the cylindrical body was necessary to flow out of the cylinder.

In order to generate such a state, when the carrier is circulated together with the fluid by aeration or agitation, if the carrier rotates irregularly, the flow rate at the contact surface increases, and the inside of the carrier is moderately increased. Should be maintained, and the sludge should be able to flow out of the carrier. From such a viewpoint, development of a new carrier has been started.

That is, the biological fixed carrier flows in a circulating flow by aeration or a stirrer in a fluidized bed type water treatment. However, since it is an accompanying flow, there is a drawback in the removal efficiency and the like under a low load state in a conventional shape having a low shape. In view of the resulting points, the present inventors have intensively studied from various directions in order to cover the weak points, and focused on a carrier having a propeller-like outer shape for the first time.

[0009] The propeller-shaped carrier, when placed in a circulating flow, meanders while rotating due to a change in water speed, and as a result, a new finding is obtained that the contact effect is enhanced. Therefore, further improvements were made to make the inside of the propeller-shaped carrier hollow and made into a cylindrical body, which was placed in a circulating flow. It has been found that the activated sludge simultaneously releases the separated sludge to the outside of the cylindrical body, and that these effects are automatically performed.

The present invention synthesizes these useful new findings,
Furthermore, it was completed as a result of studying the shape and structure of the propeller-shaped carrier, and it was a cross-sectional hollow cylindrical body, and each cross-shaped corner was rounded to give a biologically fixed carrier for water treatment. It is about. Hereinafter, the present invention will be described in detail.

One embodiment of the carrier according to the present invention is shown in the attached drawings. FIG. 1 is a perspective view of the present carrier, and FIG. 2 is a sectional view.

In the drawings, reference numeral 1 denotes a carrier. The carrier 1 is formed of a hollow cylindrical body having a cross-shaped cross section (2 indicates a carrier cross section, and 3 indicates a carrier side portion). However, each corner of the cross 2-1 and 2
At least one of -2, 2-3, 2-4 and the corner connecting portion has a roundness. Reference numeral 4 denotes a biological layer such as sludge adhered to the inner and outer wall surfaces of the cylindrical carrier 1.

As the size of the carrier, for example, the following sizes are suitable. The major axis of the carrier section 2 (2-1 to 2
-3, 2-2 to 2-4) is 7 to 15 mm (preferably 8 to
10 mm), the thickness (plate thickness) of the carrier wall is 0.2 to 0.8
mm (preferably 0.4 to 0.6 mm), the length of the carrier side 3 is within 15 mm (preferably within 10 mm), and the specific gravity is 0.90 to 0.99 (preferably 0.97 to 0.97). 0.99)
And

In the water treatment using the carrier, it is possible to use carriers having exactly the same shape and the same size, but it is necessary to appropriately mix and use the carriers having different shapes and sizes. Is also possible. In this case, in addition to the carrier having the same major axis of the carrier cross section 2, the major axis length was changed (the length of 2-1 to 2-3 and 2-2 to 2-3).
(Different lengths of 2-4) may be used.

The carrier can be made of various materials,
As the plastic, for example, polyethylene, polypropylene, polystyrene, nylon, polyurea, polyurethane, silicon resin and the like are used as appropriate, and the specific gravity is 1. Those adjusted to 0 or less are also used as appropriate.

A carrier produced from such a material can be used for water treatment as it is. However, in order to further improve the adherence of organisms such as sludge, the surface can be roughened, uneven portions can be provided, or porous material can be used. In addition to the above, for example, a foaming agent may be mixed into the material to make the material itself porous, thereby improving the adhesion.

Water treatment using the carrier may be carried out by a conventional method. For example, first, a fluidized bed made of a fluidized medium is formed in a treatment tank. As the fluid medium, any medium can be used as long as microorganisms suitable for treating activated sludge or other water to be treated on the inner and outer surfaces of the carrier are attached alone or as a mixed bacterium or as a culture. .

The water to be treated may be mixed into the fluidized bed thus formed, and subjected to aeration, agitation, etc. according to a conventional method to carry out the treatment. Examples of the water to be treated include human waste, sewage, industrial wastewater, domestic wastewater, kitchen wastewater, and various other aqueous substances. Hereinafter, use examples of the present invention will be described.

(Example 1) Nitrification of sewage was carried out using a hollow carrier made of polypropylene (outside diameter 10 mm, length 9 mm, plate thickness 0.5 mm, specific gravity 0.97 to 0.99) having the shape shown in the figure. A denitrification treatment was performed.

First, sludge for nitrification / denitrification treatment collected from a night soil treatment plant is put into two (nitrification and denitrification) treatment tanks, and a carrier is mixed into the tanks. Was allowed to adhere and proliferate. A stock solution (NH ₄ ５０50 ppm) is charged into a nitrification tank containing a fluidized medium, and dissolved oxygen is maintained at 3 to ₅ ppm by air agitation. A denitrification treatment was performed. Methanol as a carbon source was charged into the denitrification treatment tank, and the inside of the fully closed tank was mechanically stirred.

As a result, as compared with the same treatment in the activated sludge method, a result was obtained in which both the nitrification and denitrification treatments exceeded the removal rate by 10 points and the COD removal rate by as much as 40 points. The oxidation rate in the nitrification tank is extremely high as shown in the COD removal, and the ability to completely denitrify the nitrate nitrogen state can be exhibited in the denitrification tank.

After 100 days, the growth rate of the organism on the carrier is higher inside the carrier as shown in FIG. 1 and FIG. This indicates that there is also a proper flow inside. In addition, it was confirmed that the sludge adhered, multiplied, and spontaneously recovered from the sludge adhered state, which was the same as the 100 days even in the carrier after 200 days or more.

[0023]

The carrier according to the present invention can maintain a high yield due to the shape of the carrier capable of spontaneously recovering, with the rotation that enables the biological growth of the inner surface of the hollow part to be effectively exhibited, and the peeling at the same time. It has a remarkable effect.

Therefore, the present invention is outstanding in that the processing facility can be made compact by shortening the processing time, and high-grade processing by living organisms can be performed without maintenance.

[Brief description of the drawings]

FIG. 1 is a perspective view of a carrier according to the present invention.

FIG. 2 is a sectional view of the carrier according to the present invention.

Claims (5)

[Claims] 1. A cross-section comprising a cross-shaped hollow cylindrical body, each corner of the cross having a rounded shape, forming a biological layer inside the cylindrical body, allowing fluid to move inside and peeling from the inside of the cylindrical body. A biological fixed carrier for water treatment, wherein the biological organism is allowed to flow out of the cylinder. 2. An inner wall and / or an outer wall of the hollow cylindrical body is physically treated and / or a cylindrical material is treated to form irregularities on the surface, thereby immobilizing organisms. 2. The carrier according to claim 1, wherein the carrier is promoted. 3. A cross-shaped hollow cylindrical body having an outer shape of 7 to 15 mm, a length of 15 mm or less, and a plate thickness of 0.2 to 0.2 mm.
3. The carrier according to claim 1, wherein the carrier has a specific gravity of 0.95 to 0.99. 4. The carrier according to claim 1, wherein the cylindrical material is a plastic or a mixture of a plastic and an inorganic material. 5. A method for treating water containing wastewater, comprising using the carrier according to any one of claims 1 to 4.