JPS63278596A - Contact material for waste water treatment - Google Patents

Abstract

PURPOSE:To improve the treating function of the title material by coating a material obtained by mixing inorg. powder into the paste of a mixture of specified resin powder and a plasticizer on the surface of the base body made of hard vinyl chloride resin, and heating the material to obtain the contact material. CONSTITUTION:The paste consisting essentially of PVC powder and further mixed with a plasticizer (e.g., dioctyl phthalate, dioctyl adipate, etc.) and inorg. matter (e.g., calcium carbonate, silica, glass fiber, etc.) is coated on the surface of the base body consisting of hard vinyl chloride resin and prepared in the form of a plate, a sheet, a film, etc. The paste is then preheated at 60-100 deg.C to form a film on the base body, then heated at 100-230 deg.C, and baked. The initial growth rate of the microbe film is increased by the contact material thus obtained, and the deposition density is enhanced.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a contact material, and more particularly to a contact material for wastewater treatment used in the biochemical treatment of wastewater.

(Conventional technology) Conventionally, contact materials (filling materials, microorganism retainers, etc.) used in the field of biochemical treatment of wastewater, such as the sprinkled P bed method, contact oxidation method, and rotating disk method, have durability and chemical resistance. Made of hard vinyl chloride resin, it has many excellent properties such as being highly durable, free from corrosion, lightweight, excellent mechanical strength, and can be easily molded into desired shapes, as well as being inexpensive. Boards, sheets, films, etc. are often used.

(Problems to be solved by the invention) In aerobic treatment of wastewater, in the case of wastewater with high BOD concentration,
In the case of wastewater with a high biodegradation rate, microorganisms such as bacteria and protozoa that are generated are highly active and have a strong adhesion to contact materials. There is no particular problem with the use of contact materials made of contact materials made of
(OD of approximately 500 ppm or less), chemical industrial wastewater, or methane fermentation treatment in anaerobic treatment, due to the slow growth rate of microorganisms such as bacteria involved in the treatment and the weak adhesion activity of microorganisms. There were many problems, such as difficulty in performing stable and efficient processing and slow start-up of processing functions.

・1 (Means for solving the problems) The present invention solves the conventional problems related to the adhesion and growth of microorganisms as described above, without losing the excellent properties of hard PvC, and without losing the excellent properties of hard PvC. The fine irregularities formed by inorganic substances improve contact efficiency with microorganisms,
This can be used to treat wastewater such as low-concentration BOD wastewater, which normally has a slow microbial growth rate and low microbial adhesion activity, to improve the adhesion activity and achieve efficient and stable wastewater treatment. The object of the present invention is to provide a contact material for wastewater treatment (hereinafter simply abbreviated as contact material).

The gist of the present invention to achieve such an object is to add an inorganic substance insoluble in the plasticizer to a paste made by mixing vinyl chloride resin powder and a plasticizer on the surface of a substrate made of hard PVC. The contact material consists of a film formed by coating and heating the contact material.

The present invention will be explained in detail below.

The rigid PVC that serves as the base of the present invention may have various shapes such as a plate, a sheet, a film, a rod, a lump, and a chip.

In addition to simple flat shapes, the plate-like, sheet-like, and film-like materials may be corrugated, or have uneven parts, and various other types known conventionally as microbial carriers. The W may have a rough surface configuration, and the rod-shaped base may also have a surface structure such as having concave portions or convex portions.

The contact material of the present invention is a powder of vinyl chloride resin (hereinafter simply abbreviated as PvC) (preferably obtained by emulsion polymerization, but a suspension polymer) on the surface of a substrate made of hard PVC as described above. An inorganic substance that does not dissolve in the plasticizer is added to a paste made by mixing a plasticizer (which may be present) and a plasticizer (a stabilizer may also be added), and the mixture is sufficiently uniformly applied.

Next, the coating layer, which is still in a viscous state, is heated to form a hard P.
It is possible to form a film (form a solid film) onto the surface of the vC substrate at 60 to 100°C and then bake it at 100 to 230°C, or to bake simultaneously with film formation.

Further, when the hard PvC substrate is a flat plate, sheet, or film, and it is desired to finally have a corrugated plate shape or other uneven shape, the above heat baking may be performed after the processing.

When the rigid PVC substrate is a flat plate, sheet, or film, the above-mentioned paste containing PvC powder as a main ingredient and a plasticizer and an inorganic substance is applied, and then the 60-100
When preheating at 0°C to form a film on the surface of the substrate and molding it into a desired shape by vacuum forming, for example, 10
Baking may be performed by reheating at 0 to 230° C. Alternatively, after applying the paste to the substrate, film formation and baking may be performed simultaneously while immediately heating and forming.

In the contact material of the present invention manufactured by the method described above, the baking formed on the surface of the contact material forms fine irregularities on the film surface, and the surface area increases significantly.

The base of the contact material of the present invention may be made of generally hard PVC, for example, in which the amount of plasticizer added is about 10% by weight or less.

The PVC powder in the paste applied to the substrate is preferably obtained mainly by emulsion polymerization, and has an average polymerization degree of 8.
00 to 2.000, and the particle size is preferably as fine as possible, and the average particle size is usually preferably 20 to 60 μm.

The mixing ratio of such PvC powder and plasticizer is usually preferably in the range of 30 to 100 parts of plasticizer per 100 parts by weight of PVC powder (hereinafter, "parts by weight" is abbreviated as parts).

Examples of this plasticizer include dioctyl phthalate, dioctyl adipate, and tricresyl phosphate.
The plasticizer used for C is used.

In addition to the above plasticizers, PVC powder
A stabilizer may be added. Such a stabilizer is preferably a liquid stabilizer that is soluble in a plasticizer, and a solid powder stabilizer can be used by being dispersed in a plasticizer in advance.

Examples of stabilizers include basic lead phosphite, dibasic lead sulfate or calcium salts, barium salts of the above acids, and the like.

Next, the inorganic substances added to these pastes will be explained.

Examples of inorganic substances include inorganic substances that do not dissolve in the above plasticizers, such as calcium carbonate, diatomaceous earth, silica, mica, short glass fibers, glass powder, asbestos, metal powders (iron powder, alumina powder, copper powder), etc. , ferromagnetic powder is preferably used.

Examples of the ferromagnetic material include barium, a mixture of strontium and ferrite, such as barium-based and strontium-based, and manganese, a mixture of dumbbell and ferrite, including manganese-based and zinc-based, respectively. In addition, there is a rare earth ferromagnetic material that is a mixture of samarium and cobalt.

The particle size of these inorganic substances is preferably in the range of 1 to 500 μm, and the blending amount is 5 to 50 μm per 100 parts of paste.
If the amount is less than 5 parts, the surface roughness will be small, resulting in poor retention of microorganisms, and if it exceeds 50 parts, the physical properties of the film may deteriorate after film formation, which is uneconomical. .

The inorganic substance is blended into a paste consisting of PVC powder and a plasticizer (a stabilizer may be further added) in the above ratio and mixed well.

In order to apply the mixture to the surface of a rigid PVC substrate, for example, if the substrate is a flat plate, sheet, or film, a commonly used method such as a bar coater or a roll coater may be used.

In addition, when the substrate is a plate, sheet, film with an uneven pattern provided in advance, or in the shape of a rod or chip, the dipping method or other appropriate method is used.

The thickness of the coating layer is usually preferably 500 μm or less.

Thicknesses exceeding 500 μm are also effective, but uneconomical.

As mentioned above, film formation by heating after coating is done using ordinary hard P.
The temperature is 60 to 100℃ near the softening point of vC, and the baking temperature is 1
Perform at 00 to 230″C.

The contact material of the present invention obtained as described above has excellent effects as described below and can be used extremely effectively for biochemical treatment of wastewater. First, it provides an efficient bioreactor widely used in the biotechnology field.

Example 1 20 parts of iron powder with an average particle size of 10μ is added to a paste made by adding 60 parts of a plasticizer of dioctyl phthalate to 100 parts of PvC powder with an average degree of polymerization of 1,700 and an average particle size of 40μ obtained by emulsion polymerization. After adding an inorganic substance and mixing thoroughly, this was applied to the surface of a hard PVC sheet (thickness 0.25 mm) to a thickness of about 30μ, and then vacuum formed at 150℃ to form an uneven pattern. , film formation and baking were performed on the surface of the hard PvC sheet, and the obtained product of the present invention was designated as A.
shall be.

In addition, the average degree of polymerization obtained by emulsion polymerization is 1°700,
A paste consisting of 60 parts of dioctyl phthalate was added to 100 parts of PVC powder with an average particle size of 50μ.
Add 20 parts of samarium-cobalt ferromagnetic powder of μ and mix thoroughly.
m> to a thickness of about 30 μm, vacuum forming was performed at 150°C to form an uneven pattern. 1. At the same time, film formation and baking were performed on the surface of the hard PvC sheet, and the obtained product of the present invention was Let it be B.

A hard PVC sheet (thickness 0.25 mm) that does not form a coating film for comparison with the contact material of the present invention thus obtained.
A substrate having a similar uneven pattern was manufactured and designated as Comparative Example C.

Regarding these contact materials, a microbial adhesion test mainly consisting of nitrifying bacteria was conducted in a nitrifying bacteria culture tank.

Artificial wastewater containing mainly ammonium chloride was used as the water to be treated, and the nitrogen concentration was adjusted to 200 ppm.

The culture conditions were as follows: the above artificial wastewater was adjusted to 20°C and pH 7 to 8, and the test method was to place a regular corrugated parallel plate filler in the bottom of the treatment tank to cultivate nitrifying bacteria. When the nitrifying bacteria have sufficiently proliferated and adhered to the filler and the treatment performance is stable, the contact materials A and B of the present invention and the contact material of Comparative Example C are immersed in the upper part of the treatment tank, and after immersion. 1
The contact materials were pulled up on the 5th and 30th days, and the microbial amount (wet weight) of nitrifying bacteria retained on each contact material was measured 1 minute later.

The results are shown in the diagram of FIG.

In Figure 1, the vertical axis is the microbial retention amount of nitrifying bacteria (wet weight i
g/rrr), the horizontal axis is the number of immersion days (days), and A in the figure
, B is the above-mentioned example of the present invention, and C is a curve showing the microbial retention amount of nitrifying bacteria for each of the contact materials of the comparative example.

From this result, it is clear that the contact material of the present invention retains an extremely large amount of nitrifying bacteria compared to the contact material of the comparative example.

Example 2 The same contact material used in Example 1 A and B and Comparative Example C was immersed in a methanogen culture tank, and a microorganism adhesion test mainly consisting of methanogens was conducted.

The water to be treated contains acetic acid with a BOD of 5. Using artificial wastewater prepared to have OOO ppm, the culture conditions were adjusted to water temperature of 30°C and pH of 7 to 8, and the same usual filling material as above was added to the treatment tank for culturing methane-producing bacteria. The contact material of the present invention used in Example 1 and the contact material of the comparative example used in Example 1 were immersed when the methane-producing bacteria had sufficiently proliferated and adhered to the filler and the treatment performance was stable. Then, a test was conducted in the same manner as in Example 1 to measure the adhesion of methanogenic microorganisms.

The results are shown in the diagram in Figure 2.

In Figure 2, the vertical axis is the microbial retention amount of methanogens (
Wet weight g/rr? ), the horizontal axis is the number of immersion days (days),
In the figure, A and B are curves showing the amount of microbial methanogens retained in the contact material of the example of the present invention, and C is the contact material of the comparative example.

From this result, the contact material of the present invention has a lower
It is clear that the microbial retention of methanogens is extremely high.

(Effect of the invention) The contact material of the present invention has the following effects.

(1) The initial growth rate of the microbial film is fast.

(2) High adhesion density of microbial film.

(3) The microbial film has strong and stable adhesion.

(4) The microbial membrane is highly active.

(5) The coating film can be baked simultaneously with molding, and unevenness is formed on the surface of the substrate.

[Brief explanation of drawings]

Figure 1 is a chart showing the amount of microorganisms retained by nitrifying bacteria.
Further, FIG. 2 is a chart showing the amount of microorganisms retained in methane-producing bacteria. In the figure, A and B are curves showing the amount of microorganisms retained in the contact material of the example of the present invention, and C is a curve showing the amount of microorganisms retained in the contact material of the comparative example. Patent applicant: Mitsubishi Plastics Co., Ltd.
1])←

Claims (1)

[Claims] A paste made by mixing vinyl chloride resin powder and a plasticizer with an inorganic substance insoluble in the plasticizer is applied onto the surface of a substrate made of hard vinyl chloride resin and heated to form a film. Contact material for wastewater treatment.