JPH09299986A - Denitrifyihg material used for water treatment and water treatment using this material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate the need for executing replenishment at all times and to make it possible to efficiently supply nutrient sources to microorganisms by solidifying the denitrifying materials used for a denitrification treatment as one process of a water treatment as well as vegetable fibers and low-molecular saccharides by adhesives, thereby forming solid blocks. SOLUTION: The vegetable fibers are composed of, for example, 10wt.% coconut shell fibers, 15wt.% compressed scum of sugarcane and 70wt.% of waste bed logs. The low-molecular saccharides are composed of, for example, 5wt.% molasses. After these materials are mixed, the polyvinyl alcohol based adhesives are added to the mixture and the mixture is solidified to the solid blocks of, for example, a rectangular parallelepiped shape. After the blocks solidify sufficiently, the blocks are provided with many water pass holes H penetrating from one surface to the other with suitable arrangements, by which the required denitrifying materials are obtd. The nutrient sources are more efficiently supplied to the denitrifying bacteria than by the conventional alcohol, etc., and the activity of the denitrifying bacteria is enhanced. The more efficient execution of the denitrification treatment by the denitrifying bacteria is thus made possible.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to denitrification treatment performed as one process of water treatment.

[0002]

2. Description of the Related Art Many methods are already known for the denitrification treatment for removing nitrogen, which is one of the eutrophication components, from the water to be treated. One of them is to use denitrifying bacteria.
It is widely used as denitrification in water treatment by the activated sludge method. The denitrification process using denitrifying bacteria is performed by passing the water to be treated through a denitrifying tank that enables the growth of denitrifying bacteria. Normally, a nutritional source is externally supplied to support the growth and activity of denitrifying bacteria. I am trying. Alcohol, particularly methanol, is generally used as this nutrient source, and the required amount of methanol calculated is constantly supplied to the denitrification tank.

Such a method of constantly supplying alcohol as a nutrient source is widely used because there is no other suitable method, but the facility structure for that is complicated, and the method of treating water with treated water is complicated. There is a problem that alcohol is wasted out, and in the case of methanol, denitrifying bacteria that can assimilate it are limited.

[0004]

The present invention has been made against the background of such circumstances, and it is not necessary to constantly supply alcohol such as alcohol, and more efficient supply of nutrients to microorganisms. For the purpose of providing denitrification material that enables
Moreover, it aims at providing the water-treatment method using this.

[0005]

For this purpose, in the present invention, a denitrification material is obtained by solidifying plant fibers and low-molecular-weight sugars with an adhesive to form a solid block. .

Further, in the present invention, there is provided a denitrification tank in which the denitrification tank is filled with the above denitrification material, and the denitrification material is contained in the denitrification tank. The denitrification process is performed by supplying the nutrient source of the denitrifying bacterium with the assimilated material.

The plant-based fibers in the denitrifying material have a porous structure, are preliminarily treated to have an appropriate size, or can be easily processed to have an appropriate size. It is preferable to use a material that satisfies the requirements such as that a relatively homogeneous material can be stably obtained at a low cost. Examples of such materials include coconut husk fiber, sugarcane squeezed residue, wood waste, pulp, rice straw and wheat straw. Therefore, for plant fibers,
It is preferable to use any of these or a combination thereof.

As the low molecular weight sugar in the denitrifying material, it is preferable to use a molasses component, that is, a sugar contained in molasses, and glucose can also be used as a preferable one. As the molasses component or glucose, any one of these is used, or a combination thereof is used.

In the denitrifying material according to the present invention, the plant fibers and the low-molecular-weight saccharide contained in the material serve as assimilation and supply a nutrient source to the denitrifying bacteria. The low-molecular-weight saccharides are carried in a state of adhering to the plant fibers, and the plant fibers are solidified with an adhesive. Therefore, it does not flow out like alcohol, and it is possible to supply a nutrient source necessary for denitrifying bacteria for a long time by only supplying an appropriate amount once. In particular, because it is a complex assimilation by mixing plant fibers made of cellulose and lignin, which are relatively poorly digestible to microorganisms and low-molecular-weight sugars that are relatively digestible to microorganisms, Since the consumption rate of low-molecular-weight sugars, which have good digestibility and are easy to use, can be appropriately suppressed by the plant fibers, it is possible to more stably supply nutrients for a long time. Further, the denitrification material according to the present invention, the plant fiber, coconut husk fiber, squeezed residue of sugar cane, wood waste, pulp, rice straw and wheat straw by using those having a porous structure, such as these, Due to the large number of pores in, the denitrifying bacteria can be provided with a comfortable place as a so-called micro-habitat effect, and it also functions to further enhance the activity of the denitrifying bacteria.

The denitrifying material as described above may be further added with a porous material having pores of a more suitable size as a microhabitat for denitrifying bacteria. Charcoal and coke are typical examples of such a porous material. In this way, by adding a porous material having a high microhabitat property, it is possible to further enhance the fixing property of the denitrifying bacteria and improve the denitrifying efficiency by the denitrifying bacteria.

Further, the denitrifying material as described above is provided with water passage holes for increasing the contact property with the water to be treated at appropriate intervals so that even if it is formed in a large size, It is possible to ensure a sufficiently effective contact. That is, the size of the denitrification material can be increased by providing the water passage hole. This brings a great advantage to the manufacturing process of the denitrification material, and also brings a great advantage to the handling property when the denitrification material is filled in the denitrification tank. When the water passage hole is provided in this way, in order to facilitate the boring process,
The shape of the solid block in the denitrification material is preferably a cube or a rectangular parallelepiped.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION In order to carry out the denitrification material according to the present invention in a preferred form, 1 coconut husk fiber is used as the plant fiber.
0% by weight, squeezed sugar cane residues by 15% by weight, waste wood wastes by 70% by weight, and molasses as low-molecular-weight sugars by 5% by weight. And after mixing them well,
Add an appropriate amount of polyvinyl alcohol adhesive to solidify into a solid block. The shape of the solid block is, for example, a rectangular parallelepiped shape as shown in FIG. Then, after sufficiently solidified, as shown in FIG. 1, a large number of water passage holes H penetrating from one surface to the other surface are provided in an appropriate arrangement.

Next, an embodiment of the water treatment method according to the present invention will be described. As shown in FIG. 2, a treatment facility including a pretreatment section 1, a denitrification section 2, and a posttreatment section 3 is used. In the pretreatment section 1, for example, the biofilm method and the activated sludge method are used to treat BOD components and preliminary denitrification treatment. In the denitrification section 2, denitrification treatment using denitrifying bacteria is performed, and the posttreatment section is used. In 3,
A final finishing process is performed on the remaining BOD components and the like.

Denitrification Section 2 Characteristic of the Present Invention
Includes a denitrification tank 5 as shown in FIG. The denitrification tank 5 is provided with a filling section 6, and the denitrification material 7 is provided in the filling section 6.
Are combined and filled by an auxiliary material 8 using, for example, a large amount of shiitake mushroom waste wood so as to provide an appropriate gap for water passage. Further, a water guiding section 9 is provided along the filling section 6, and the water to be treated is introduced through the water guiding section 9 so that the water to be treated flows through the filling section 6 in a flow indicated by an arrow.

In such a denitrification tank 5, the denitrifying bacteria act under the anaerobic condition with the assimilative substance contained in the denitrifying material 7 as a main nutrient source. Denitrification is performed by reducing to gas.

[0016]

As described above, according to the present invention, a nutrient source can be supplied to denitrifying bacteria more efficiently as compared with conventional alcohols and the activity of the denitrifying bacteria can be enhanced. Therefore, the denitrification treatment with the denitrifying bacteria can be performed more efficiently.

[Brief description of drawings]

FIG. 1 is a perspective view of a denitrifying material according to an embodiment.

FIG. 2 is a schematic diagram of a treatment facility used in the water treatment method according to the embodiment.

3 is a simplified cross-sectional view of a denitrification tank in the treatment facility of FIG.

[Explanation of symbols]

 1 Pretreatment section 2 Denitrification section 3 Posttreatment section 5 Denitrification tank 6 Filling section 7 Denitrification material

Claims (4)

[Claims] 1. A denitrifying material obtained by solidifying a plant fiber and a low-molecular-weight saccharide with an adhesive to form a solid block. 2. The denitrification material according to claim 1, wherein the plant fibers include at least one of coconut husk fibers, sugarcane squeezed debris, wood waste, pulp, rice straw or wheat straw. 3. The denitrifying material according to claim 1, wherein the low-molecular-weight saccharide contains at least either molasses component or glucose. 4. A water treatment method in which water to be treated is passed through a denitrification tank capable of propagating denitrifying bacteria to denitrify the water to be treated, wherein the denitrification tank is any one of claims 1 to 3. The method for treating water is characterized in that the denitrifying material is filled, and the denitrifying treatment is performed by supplying a nutrient source for denitrifying bacteria by the denitrifying material.