JPH0788491A - Microorganism treatment method for water contaminated with hardly decomposable aromatic compound - Google Patents

Abstract

PURPOSE:To treat with microorganisms water contaminated with aromatic compounds such as phenol which are hardly decomposable by microorganism treatment without employing a simple active carbon adsorption method. CONSTITUTION:In the microorganism treatment of water contaminated with aromatic compounds which are hardly decomposable, the contaminates adsorbed on active carbon are decomposed stepwise by microorganisms using a rotary disk filter bed carrying the active carbon.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for decomposing aromatic compound-based hardly decomposable substances by treating microorganisms with water contaminated with aromatic compound-based hardly decomposable substances.

[0002]

2. Description of the Related Art Leachate from landfills such as municipal waste contains aromatic compound-based persistent substances (hereinafter referred to as persistent substances) derived from various plastic products and other chemical products. Often. Even if such water is treated by a general aerobic microbial treatment method, only the hardly decomposable substance is hardly decomposed and flows out. As a method for treating water contaminated with such a persistent substance,
Since there is only a method of adsorbing the hardly decomposable substance using the activated carbon, there is a problem that it takes time and money to replace the activated carbon having adsorbed the hardly decomposable substance up to the adsorption capacity with a new activated carbon.

[0003]

Therefore, the present invention is intended to provide a method for treating water contaminated with an aromatic compound-based hardly decomposable substance by a microbial treatment, not by a simple activated carbon adsorption method.

[0004]

DISCLOSURE OF THE INVENTION The present invention relates to the treatment of water contaminated with an aromatic compound-based persistent substance by a microbial treatment method to decompose the aromatic compound-based persistent substance in water. The apparatus is characterized by using a rotating disk filter bed in which activated carbon is supported on the rotating disk.

The rotating disk filter bed is a microbial treatment device also called a biodisc filter. In general, dozens of discs with a diameter of 1 to 3 m and a thickness of 0.7 to 20 mm are fixed to a rotating shaft at intervals of about 2 cm, and the disc is attached to the processing tank with the rotating shaft horizontal. Thus, about half of the disk surface is slowly rotated while being immersed in the waste water.

In the present invention, activated carbon is supported on the rotary disc of the rotary disc filter bed. The specific activated carbon supporting method is not particularly limited as long as the activated carbon on the disk can be brought into contact with the water to be treated as the disk rotates, but it is not particularly limited. In addition to the above, it has a large number of through holes (water-permeable holes), and the hollow portion thereof may be filled with activated carbon. During the operation of the device, water permeates the inside of the disc through the water-permeable holes and comes into contact with the activated carbon inside. In order to prevent the activated carbon from leaking out from the water permeable hole, the water permeable hole is covered with a metal net or the like, or the activated carbon is packed in a bag made of net or knitted fabric and then put in the hollow portion of the disc. As activated carbon,
A granular material having a particle size of about 0.5 to 5 mm is suitable.

As the material of the rotary disc, there can be used foamed plastic, plastic, water-resistant plywood, metal plate and the like which are commonly used for a rotary disc filter bed. When water that is difficult to decompose is treated with a rotating disk filter bed that uses a disk that supports activated carbon, first, by acclimatization, as in the case of general organic wastewater treatment with a rotating disk filter bed, A microbial film is formed on the disk surface and the activated carbon surface.
At this time, since the surface area of activated carbon is large, the amount of adhered microorganisms per disc is significantly larger than that when no activated carbon is supported (on the surface of activated carbon, in addition to general organic substance-decomposing bacteria, hardly decomposable substance decomposing bacteria Adhere to). Since the concentration of organic matter on the surface of activated carbon on which organic matter is adsorbed is higher than that in water, microorganisms on the surface of activated carbon proliferate vigorously, and accordingly, persistent substances are also actively taken in and decomposed.
As described above, the hardly decomposable substance is surely decomposed and the purified water is discharged.

[0008]

Example An artificial wastewater having the following composition was treated with a laboratory rotary disc filter bed. Glucose aqueous solution (50g / l) 10ml K ₂ HPO ₄ (21.7g / l), KH ₂ PO ₄ (8.5g / l), Na
An aqueous solution of ₂ HPO ₄ · 12H ₂ O (44.6 g / l) and NH ₄ Cl (1.7 g / l) 0.27 ml MgSO ₄ · 7H ₂ O (22.5 g / l), FeCl ₃ · 6H ₂ O (0.
25 g / l), NH ₄ Cl (46.4 g / l) aqueous solution 1 ml CaCl ₂ aqueous solution (27.5 g / l) 1 ml Polypeptone 0.15 g Persistent substance (phenol) 0.05 g

[0009] The above items (1) to (4) were mixed, water was added to make the total amount 1
000 ml and adjust pH to 7.0 (BOD: 220
0ppm, COD: 500ppm, total nitrogen: 32ppm, phosphorus:
3.5 ppm).

The rotating disc filter bed used is as follows. Treatment tank volume: 2100 ml Rotating disk Comparative example 6 pieces with a diameter of 17 cm and a thickness of 1 cm are fixed to the rotating shaft at 1 cm intervals Total surface area: 2750 cm ² ; Material: Vinyl chloride resin; Rotation speed: 8 rpm Example Above comparative example A hollow structure, and water-permeable holes with a diameter of 15 mm are formed on the entire surface at intervals of 25 mm. In the hollow part,
Fill with granular activated carbon in a nylon fabric bag (activated carbon filling amount: 54 g / disc).

In the above equipment, the BOD area load is 5 g / m ² ·
The artificial wastewater was continuously supplied and treated continuously on a daily basis. During the experiment, COD, BOD, and phenol concentration were measured for the treated water flowing out from the treatment tank. The experimental results are shown in Tables 1 to 4.

[0012]

[Table 1] Average value from 0 to 15 days from the start of the experiment (unit: ppm)

[0013]

[Table 2] Average value of 30 to 45 days from the start of the experiment (unit: pp
m)

[0014]

[Table 3] Average value 60 to 75 days after the start of the experiment (unit: pp
m)

[0015]

[Table 4] Average value of 300 to 315 days from the start of the experiment (unit:
ppm)

In the above experiment, phenol is activated carbon 1
Although 0.10 mg / day was supplied per g, the treated water was treated even after treating the phenol in an amount exceeding the saturated adsorption amount calculated from the phenol adsorption capacity of the activated carbon used (time shown in Table 4). The concentration of phenol was 0, and it was confirmed that the rotating disk supporting the activated carbon did not function as a simple phenol adsorption device but promoted the microbial decomposition of phenol.

[0017]

As described above, according to the method of the present invention, it is only necessary to support the activated carbon on the rotating disk, and the activated carbon supported does not need to be replaced for a long period of time. There is no difference from the treatment of municipal sewage using a disc filter bed, so that water contaminated with aromatic compound-based hardly decomposable substances can be easily and efficiently cleaned, and the treatment effect is extremely reliable.

Claims (1)

[Claims] 1. When decomposing the aromatic compound-based hardly-decomposable substance in water by treating the water contaminated with the aromatic compound-type hardly-decomposable substance by a microbial treatment method, activated carbon is applied to a rotating disk as a treatment device. A method for treating microorganisms of water contaminated with an aromatic compound-based hardly decomposable substance, characterized by using a supported rotating disk filter bed.