KR20010088735A - A method for manufacturing density-controlled tube-chip type biocarriers and the biocarriers manufactured thereby - Google Patents

Abstract

PURPOSE: A manufacturing method of tube chip type biomedia with specific gravity adjusted and biomedia thereof is provided, which can adjust the final extruding specific gravity to 0.93-1.02 by controlling the constituent ratio of polymer supporting material, activated inorganic material and adjusting agent of specific gravity, so that the media can be kept as a floated state thus eliminating any necessity of installing additional facility to float the media. CONSTITUTION: The manufacturing method is as follows: (i) mix 5-40 wt.% of activated inorganic material and the balance being polymer to make total weight of 100 wt.%; (ii) mold an extrudate in the hollow tube form of 0.93-1.02 specific gravity by melt extruding; and (iii) cool and cut the extrudate.

Description

TECHNICAL FIELD OF THE INVENTION A method for producing a tube chip-type microbial carrier having a controlled specific gravity and a microbial carrier prepared therefrom

The present invention relates to a method for producing a tube chip-type microbial carrier having a specific gravity control and a microbial carrier prepared therefrom. More specifically, the present invention relates to a method for producing a tube chip-type microbial carrier excellent in microbial adhesion and activity, and to a microbial carrier prepared therefrom, which is operable in the form of a floating bed and a fluidized bed in a submerged float.

In general, biological wastewater treatment methods can be largely divided into activated sludge method and biofilm method, and in recent years, researches on biofilm methods capable of high efficiency and high efficiency operation have been conducted.

The biofilm method is excellent in the removal efficiency for contaminants because the microorganism is attached to the carrier at a high concentration, it is possible to preserve the low growth rate microorganism in the carrier. In addition, it has a stable distribution of ecosystems and micro-animals, prevents sludge swelling, and shows stable removal efficiency even at high / low concentration loads. Moreover, the amount of sludge generated is small and the reactor can be miniaturized.

Microbial carriers used in the biofilm process are classified into high molecular and inorganic material (ceramic or activated carbon) carriers depending on the material. Polymeric carriers are convenient because they are inexpensive and can be manufactured in the desired shape.By themselves, the specific surface area is small and the surface is physicochemically inert and not coarse.In low aeration conditions, the biofilm thickens and becomes entangled. Under conditions, desorption of immobilized microorganisms frequently occurs, as well as a large amount of sludge generation.

In contrast, activated carbon or ceramic-based inorganic material carriers have the advantage of having a specific surface area, rough surface, and adsorption capacity for contaminants, which have a thin microbial film and a small amount of sludge generation, but are difficult to form the carrier into a desired shape and are manufactured by high temperature firing. There is a disadvantage in that the manufacturing cost is high. In addition, there is a problem that loses the adsorptive properties of the surface of the carrier due to high temperature firing during manufacturing.

As a polymer carrier, a carrier in the form of a fiber yarn or a network structure is disclosed in Korean Patent Publication Nos. 97-54729, 95-1251 and the like or Japanese Patents 09-001175 (1997) and 00-288569 (2000). Patents 09-051794 (1997) and 01-000180 (2001) include polymer sponge forms, Japanese Patents 05-271425 (1993), 10-180282 (1998), 63-224795 (1988), 01-256387 (1989), and the like. A hydrophilic or hydrophilic polymer coated with particles is disclosed. However, such a carrier has a problem in that the thickness of the biofilm is formed due to the inactivity of the surface thereof, the detachment easily occurs, and the amount of sludge is generated. In addition, in Korean Patent Publication Nos. 98-64937 and 98-64939, when using microbial contact materials such as nonwoven fabrics or sponges, a pyramidal or diamond-shaped superimposed skeleton structure is removed to reduce the release of microbes. Although the microorganisms are attached to the outer skeleton again, the method does not escape the limitations of the polymer carrier.

Inorganic material carriers include, for example, Korean Patent Publication Nos. 95-17825, 96-28966, and 97-6249; It is disclosed in Japanese Patent Nos. 64-043189 (1989), 02-131578 (1990), 09-220089 (1997), and the like, and has excellent reaction activity and a thin biofilm, while having a high firing temperature and a desired shape and size. It is difficult to mold into the furnace, which lowers economic efficiency and is impractical.

As a method of mixing a polymer material and an inorganic material, a polyurethane hexahedron of Korean Patent Publication No. 99-76405, a tire of Japanese Patent No. 09-164392 (1997), and a Japanese patent using a method of coating activated carbon with an organic adhesive on a polymer 00-004880 (2000) is disclosed, such as polyethylene particles, and the Republic of Korea Patent No. 00-1461 introduces a carrier coated with a mixture of activated carbon and clay in a polymer tube-shaped chip, but the carriers have a specific gravity greater than 1.0 to support the carrier In order to operate in a fluidized bed in water, there is a problem in that a large amount of air must be supplied or a fluidized bed must be operated in a fixed bed. In addition, desorption of the coated inorganic material powder is expected during long-term operation and has a disadvantage in that the manufacturing cost is expensive. As an example of physically mixing a polymer and an inorganic material, Japanese Patent No. 08-173984 (1996) discloses a carrier extruded into a tube chip having a diameter of 5-30 mm and a specific gravity of 1.03-1.10 by mixing CaCO ₃ in polyethylene. CaCO ₃ has little microbial activity and specific gravity greater than 1.0, making it impossible to use as a fluidized bed. In addition, Korean Patent Publication No. 99-6932 discloses a large wood kiln type manufactured by crushing-firing-mixing materials such as stone powder, activated carbon, and filtered sand to pulverized waste vinyl, and extruding and cooling with an extruder equipped with a C-type die. Although a method of operating by fixing a contact medium in a lattice form in a bioreactor has been disclosed, the carrier has a large surface area and occupies a large volume, thereby reducing HRT (hydraulic retention time) in the reactor.

On the other hand, when the specific gravity is greater than 1 when the carriers are mounted in the reactor, it is put into a net or a screen is installed at the bottom to operate as a fixed bed (Packed-bed), so long-term operation, such as the blockage between the carriers due to sludge is a concern. Or if the specific gravity is too small, the carrier rises on the surface of the water and is not effective due to the fluidization (fluidization) or the drift phenomenon biased to one side of the reactor by blowing air. In addition, the carrier-molded form is advantageous in that the hollow form than the hollow rod or granulate form does not reduce the HRT due to the large geometric surface area to which microorganisms attach and occupies a small volume in the reactor. A hollow tubular carrier that can be extrusion molded rather than injection molding is economical in terms of manufacturing cost.

The present inventors also used a method of producing a clay-based microbial carrier having a higher activity than conventional plastic or ceramic carriers by using a combination of two or more inorganic materials mixed with activated carbon and inorganic clay and baking at low temperature, and the clay-based inorganic powder The highly active carriers prepared by coating them by using an adhesive on the surface of a tube chip-type polymer support have been previously filed as Korean Patent Applications Nos. 99-18219 and 2000-1461. However, the coating method has a problem that the adhesive is expensive, the coating method is difficult, and the final specific gravity of the prepared carrier is greater than 1.00 to install and operate the carrier in a fixed phase in the reactor.

Accordingly, an object of the present invention is to provide a method for producing a tube chip-type microbial carrier whose specific gravity is adjusted so that it can be operated in a floating float and fluidized bed.

Another object of the present invention is to provide a method for producing a tube chip-type microbial carrier having excellent microbial adhesion and activity.

Still another object of the present invention is to provide a tube chip type microbial carrier having a specific gravity controlled by the method of the present invention and having excellent microbial adhesion and activity.

1 is a cross-sectional view showing various forms of the tube chip carrier of the present invention.

According to the first aspect of the present invention,

Mixing and melting and extruding 5-40% by weight of the active inorganic material and the remainder of the polymeric material so that the total weight is 100% by weight, thereby forming an extrudate in the form of a pupil tube having a specific gravity of 0.93-1.02; And

Cutting the extrudate after cooling;

Provided is a method of manufacturing a tube chip-type microorganism carrier having a specific gravity including a controlled density.

According to the second aspect of the present invention,

A tube chip microorganism carrier having a specific gravity of 0.93-1.02 produced by the method of the first aspect is provided.

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated in detail.

In the method of the present invention, in the anaerobic tank without agitation, the specific gravity of the tube chip-type microorganism carrier is controlled so that the carrier can be operated in the submerged floating form in which the carrier does not sink to the bottom in the reaction tank and is not completely injured, and in the stirred aerobic tank. Is prepared. As described above, the microbial carrier having a specific gravity controlled by the method of the present invention is present in a floating float form and a fluidized bed in the reaction tank, so that the mixing and oxygen transfer effect of the waste water is high and the carrier sinks to the bottom even during long-term operation. It can also be operated without entanglement between the carriers or blockage of the reactor.

In order to prepare a microbial carrier having such a specific gravity, first, the active inorganic material having excellent activity in biological sewage and wastewater treatment and the polymer material used as a support are mixed and melted and extruded into a tubular (pores).

As the active inorganic material, a carbon-based active inorganic material and a crystalline or amorphous clay-based active inorganic material are used. Preferred activated group materials for the present invention are selected from the group consisting of, but not limited to, activated carbon, charcoal, coke, carbon black, peat, silica, alumina, zeolite, diatomaceous earth, slag, volcanic ash, combustion ash and kaolin. Such active inorganic materials may be used in a mixture of two or more kinds in terms of increasing surface roughness, increasing surface area, adsorbing contaminants, growing microorganisms, supplying nutrients, and delivering oxygen. The active inorganic material is preferably included in 5-40% by weight based on the weight of the microorganism carrier of the present invention. When the active inorganic material is included in 5% by weight or less, the carrier performance is lowered, and when included in more than 40% by weight, the physical properties of the polymer support is reduced, making it difficult to extrude in the extruder. More preferred content ratio of the active inorganic material is 10-30% by weight based on the weight of the microorganism carrier of the present invention.

As the polymer material used as the support, any polymer material melt-extruded with an extruder may be used. For example, polyolefins, polyvinyl chloride (PVC), polystyrene (PS), polyesters, natural or synthetic rubber may be used alone or in a mixture of two or more. As such a polymer material, all raw materials or recycled materials may be used.

The active inorganic material and the polymer material are mixed, melted and extruded into a hollow tubular extrudate, and the extrudate is cooled and cut to prepare a microbial carrier in the form of a tube chip.

The extrudate of the present invention is made of an extrudate whose specific gravity is in the range of 0.93-1.02 so that it can be operated in submerged floating and fluidized bed forms when applied. If the specific gravity of the extrudate of the active inorganic material and the polymer material is out of the range of 0.93-1.02, the specific gravity of the extrudate is adjusted to 0.93-1.02 by adding a specific gravity regulator.

Specific gravity regulators, such as polyethylene, when the specific gravity of the polymer material is less than 1, high specific materials such as talc, high specific gravity powder, barium sulfate (BaSO ₄ ), magnesium hydroxide (Mg (OH) ₂ ) and to increase the specific gravity and If the specific gravity of the polymer material is 1 or more, such as polyester, for example, low specific gravity powder, calcium carbonate (CaCO ₃ ), high-temperature decomposable inorganic salts such as ammonium carbonate and ammonium nitrate, organic decomposers such as cellulose, isocyanate A specific gravity reducing agent including a foaming agent such as or a lightweight material such as pumice is added.

The specific gravity control agent may vary depending on the specific gravity of the polymer material, the content of the active inorganic material and its specific gravity, and the extrusion conditions during final extrusion. In preparing the microbial carrier of the present invention, the polymer material, the active inorganic material and the specific gravity control agent are mixed to be 100% by weight. The active inorganic material is mixed at 5-40% by weight as described above, the specific gravity regulator is preferably mixed at 0-20% by weight if necessary, and the balance is composed of a polymeric material. If the specific gravity regulator is mixed in more than 20% by weight, the carrier efficiency to act as a microbial carrier may be lowered.

The active inorganic material, the polymer material, and the specific gravity modifier component, which are prepared as described above, are mixed and melted and extruded into a hollow pupil-shaped tubular extrudate.

In extrusion, the microbial carriers are molded into hollow tubular extrudate. At this time, it is preferable to mold the tubular extrudates having a diameter (D) of 5-100 mm, more preferably in the range of 7-50 mm. Molding into tubes less than 5 mm in diameter is uneconomical, and exceeding 100 mm is undesirable due to the reduced surface area. On the other hand, the tubular extrudate is cut so that its length is usually 0.5-1.5 times the diameter, more preferably 0.7-1.2 times. If the length is too short, microbial adhesion to the inner surface is not smooth, and if too long, the inner passage is blocked. The surface area of the hollow tube chip carrier is about 30-40% wider than the granule carrier of the same size, but the material cost is economical because it can be used at least 1/5 less than that of the solid carrier. On the other hand, the tube shape may be any type of tube shape, such as cylindrical, polygonal, open type tube, as shown in Figure 1, of which the cylindrical shown in Figure 1 (a) is the most practical and efficient. Furthermore, the tubular carrier, in particular, a cylindrical or polygonal tube form in which a partition is additionally installed in the tubular carrier having a diameter of 10 mm or more or an uneven surface is formed on the inner surface to increase the surface area. Carriers of this type are economical and efficient due to their low related materials and large surface area. This increase in geometric surface area improves contaminant removal efficiency, as well as the inner surface of the tubular carrier being a weak habitat for low adherence or higher microorganisms.

The microbial carrier, which is an extrudate of a polymeric material, an active inorganic material and an optional specific gravity control agent, has a specific gravity of 0.93-1.02, preferably 0.95-0.99. If the specific gravity is less than 0.93, even if air is supplied, the carrier will not be fluidized while floating on the water.If the specific gravity exceeds 1.02, the carrier will not flow and will sink in the water after forming the biofilm. in need. The microbial carrier prepared by the present invention having a specific gravity in the above range can be used by putting it into a bioreactor without a separate installation for preventing the carrier from sinking to the bottom such as a net or a screen support. At this time, the microbial carrier having a specific gravity of 0.93-1.02 is maintained in a submerged injured state, which does not sink to the bottom of the reactor and does not float on the water surface. By using this phenomenon, the microbial carrier of the present invention in an anaerobic tank that is not stirred can be operated in the form of a biofilter while maintaining a submerged floating bed (immersed self-floating bed) under the water surface and passing the fluid upward.

On the other hand, in an anaerobic or aerobic tank using a stirrer, the microbial carrier of the present invention can be operated in the form of a perfectly mixed fluidized bed with no agitation even at low agitation or low air volume. In addition, it is possible to operate the reactor stably without the phenomenon of thickening of biofilm or entanglement between carriers due to friction between carriers even during long-term operation.

The tubular chip microbial carrier having a specific gravity of 0.93-1.02 prepared by the present invention is exposed to the surface of the tube by mixing the active inorganic material powder with the polymer material, so that contaminants in the waste water are efficiently adsorbed in the carrier and have high microbial adhesion. Furthermore, the thickness of the biofilm is kept thin and shows high activity in wastewater treatment. In addition, the microorganism carrier prepared according to the present invention has a sufficient amount of the active inorganic material added in the polymer coating of the active inorganic material disclosed in Patent 2000-1416 to the polymer only 1 / 2-1 / 5 level and sufficient surface It has roughness to provide a wider microbial habitat and there is no desorption of microorganisms and active ingredients.

Hereinafter, the present invention will be described in more detail with reference to Examples.

Example 1

As a final component, the remaining polypropylene was mixed and melted in an extruder so as to have 4% by weight of coke, 1% by weight of activated carbon, 2.5% by weight of zeolite, 2.5% by weight of steel slag, 5% by weight of talc, and 100% by weight. A circular tube chip-shaped microbial carrier having a length of 8 mm and a specific gravity of 0.976 was prepared and administered at a volume of 30 vol.

Meanwhile, except that the composition of the active inorganic material was changed to 2% by weight of coke, 6% by weight of zeolite, and 1% by weight of steel slag, a microbial carrier and a tube chip-shaped carrier having a specific gravity of 0.97 were prepared, and 30 parts of 400 liters of aerobic tank 2 Administered in%.

30 liters / minute air was injected into one tank of exhalation, and 20 liters / minute air was injected into 2 tanks of exhalation through the blower attached to the bottom. After 2 days, the carrier was completely flowed up and down in the reactor and fluidized without drift. While operating under the fluidized bed condition, the measured intake was measured as 1 trillion and 6 hours and 2 trillion and 4 hours as the HRT (hydraulic retention time) compared to the influent sewage, and the average influent COD concentration was 220 ppm and the NH3 + -N concentration was 45 ppm. The COD removal rate of the effluent reached 95% and the nitrification rate reached 96%.

Example 2

300 liters of anoxic tank was connected to the front stage of the aerobic tank of Example 1, and 1% by weight of activated carbon, 2% by weight of coke, 3% by weight of zeolite, 1.5% by weight of steel slag, 1% by weight of kaolin, and 5% by weight of talc. And the remaining polypropylene to be 100% by weight to prepare a round tube chip carrier having a diameter of 7mm, thickness of 0.7mm, length of 7mm and specific gravity of 0.965, and administering 50% by volume, inflow of the influent into the submerged fixed bed without stirring. It was driven to flow. The influent was based on 1 tank of HRT 6 hours, 2 tanks of HRT 4 hours, and 3 hours of anaerobic HRT. When the steady state was reached, the COD removal rate was 95%, the nitrification rate was 95%, and the denitrification rate was 92%.

Example 3

The carrier used in Example 2 was operated by filling a 16 m3 / day sewage treatment facility with 30% by volume of each reactor (1 tank 4 m3, 2 tanks 2 m3, 1 tank aerobic, 1.5 m3). After several months, the steady state reached a 92% COD removal rate, 95% nitrification rate and 91% denitrification rate.

Example 4

The same reaction tank and carriers as in Example 1 were used to treat waste land leachate. At this time, it operated as 1 set of HRT 12 hours and 9 hours of 2 pairs HRT. When raw water with 2000 ppm COD and 200 ppm ammonia was introduced, the COD removal rate was 84% and the nitrification rate was 94%.

Example 5

The final component is composed of the balance polyethylene so that 2% by weight of coke, 7% by weight of activated carbon, 4% by weight of zeolite, 2% by weight of steel slag, 3% by weight of talc, 2% by weight of ammonium nitrate and 100% by weight, and has a diameter of 7 mm and thickness 0.5mm, 8mm in length, specific gravity 0.98 was prepared in a circular tube chip-type microbial carrier and injected into the column reactor of 10cm in diameter and 50cm in length at 40% by volume, the dehydration waste liquid (SCN 60,000ppm, CN 5ppm, 20% dilution of 50,000 ppm of cations such as Na and 50,000 ppm of anions such as Cl) was conducted in a fluidized bed with sufficient air blown from the bottom while flowing into the upstream. It was%.

Comparative Example 1

Polyurethane porous sponge carrier was cut into 10mm cube form and administered in the same reactor as in Example 1 at 30% by volume, and tested under the same conditions as in Example 1, and the COD removal rate was 87% and the nitrification rate was 75%.

Comparative Example 2

An active inorganic material including 50% by weight of zeolite, 30% by weight of steel slag, 10% by weight of diatomaceous earth, and 10% by weight of activated carbon was coated on the polyethylene support to prepare a tubular carrier having a diameter of 7 mm, a thickness of 0.5 mm, and a length of 7 mm. In the same reactor as in Example 5, 40 vol% of the carrier was filled with a screen installed at the bottom, and tested under the same conditions as in Example 1, and the dehydration waste removal rate was 90%.

Through the above examples, it can be seen that the tube chip-type microbial carrier having a specific gravity control of the present invention has the following advantages.

(1) The final specific gravity can be adjusted to 0.93 ~ 1.02 during extrusion molding by adjusting the component ratio of the polymer support material, the active inorganic material and the specific gravity control agent, so that the carrier does not sink to the bottom after being introduced into the reactor and remains submerged under water. There is no need to install additional equipment to fix or disperse the carrier in the reactor.

(2) In the anaerobic tank without fluid agitation, when the carrier exists as a submerged floating bed under the water surface and the fluid flows upward, the sludge deposition in the carrier, the blockage and the drift of the carrier layer are improved, and the operation efficiency is increased.

(3) Agitated anaerobic or aerobic tanks can be easily fluidized with weak agitation or a small amount of air without floating or drift of the carrier in fluidized bed operation. This increases.

(4) The presence of active inorganic materials on the surface of the polymer improves the hydrophilicity, the surface is rough, the adhesion of microorganisms is improved, the number of individuals is increased, the biofilm is kept thin by the adsorption of contaminants by active inorganic materials, and the reactivity is increased. Excellent control of pollutants, it can be applied to the treatment of high concentration organic wastewater or hardly degradable wastewater.

(5) Because the final product is a tube type that is physically mixed with a small amount of active inorganic material and melt-extruded, it is economical because there is less related material and the production per hour is higher than injection molding, and the surface area of the carrier is large and HRT loss after entering the reactor It is almost permanent and there is no surface detachment of inorganic material even in long-term operation.

Claims (13)

Mixing and melting and extruding 5-40% by weight of the active inorganic material and the remainder of the polymeric material so that the total weight is 100% by weight, thereby forming an extrudate in the form of a pupil tube having a specific gravity of 0.93-1.02; And Cutting the extrudate after cooling; Tube chip type microbial carrier manufacturing method having a controlled specific gravity comprising a. The method according to claim 1, wherein the specific gravity modifier is mixed and melted together with the active inorganic material and the polymer material so that the specific gravity of the extrudate is 0.93-1.02 to form an extrudate. The method of claim 1, wherein the polymeric support material is selected from the group consisting of polyolefin, polyvinyl chloride (PVC), polystyrene, polyester, and rubber. The method of claim 1, wherein the active inorganic material is selected from the group consisting of activated carbon, charcoal, coke, carbon black, peat, silica, alumina, zeolite, diatomaceous earth, slag, volcanic ash, combustion ash and kaolin. Tube chip type microbial carrier manufacturing method with controlled specific gravity. The method of claim 2, wherein the specific gravity regulator is talc, high specific gravity powder, barium sulfate (BaSO ₄ ), magnesium hydroxide (Mg (OH) ₂ ), low specific gravity powder, calcium carbonate (CaCO ₃ ), ammonium carbonate, ammonium nitrate , Cellulose, isocyanate or pumice, characterized in that the specific gravity-controlled tube-chip type microbial carrier manufacturing method. The method of claim 2, wherein the specific gravity control agent comprises 0-20% by weight based on the weight of the microbial carrier. The method of claim 1, wherein the extrudate is a microbial carrier manufacturing method, characterized in that the hollow tube of 5-100mm in diameter. The method of claim 1, wherein the tube chip type microbial carrier is a method for producing a microbial carrier, characterized in that the length-to-diameter ratio is in the range of 0.5-1.5. The method of claim 1, wherein the tube chip-type microbial carrier is a microbial carrier manufacturing method, characterized in that the form of a circular or polygonal tube. The method of claim 1, wherein the tubular microbial carrier is a tubular microorganism carrier manufacturing method, characterized in that the tubular structure is increased by additionally installing a partition therein or the surface irregularities to increase the surface area. The method of claim 1, wherein the final specific gravity of the extrudate is in the range of 0.95-0.99. A tube chip type microbial carrier having a specific gravity of 0.93-1.02 prepared by the method of any one of claims 1 to 11. 13. The mixed fluidized bed according to claim 12, wherein in the anaerobic tank without an agitator when the carrier is applied, it is operated in a submerged float by maintaining an imbedded self-floating bed under the surface of the water, and in the anaerobic or aerobic tank using the agitator, there is no drift. A microbial carrier having a specific gravity of 0.93-1.02, characterized in that it is operated in the form.