KR20010028619A - A method of manufacturing egg shell type media for biological wastewater treatment and offensive odor removal - Google Patents

Abstract

PURPOSE: A method for manufacturing fluid biomedia of hollow ball type for sewage/wastewater treatment and odor removal is provided. The biomedia excellent in pollutant removal efficiency can remove pollutant stably even in fluctuations in loads of flow rate/concentration of sewage/wastewater, because high concentration microorganisms proliferate in the hollow ball shaped biomedia by adding sawdust, foaming plastic particles, and other pore controlling agents to the biomedia for forming a gap or pores. CONSTITUTION: The method comprises: i) coating adhesive and active media(2) on a floating body(1) composed of foaming plastic particles having a specific gravity of less than 1.0g/cm¬2, wherein the weight ratio of the adhesive and the active media(2) is 60-95:40-5; and ii) primarily plasticizing at 80-150de.C for 5mins-5hrs to harden the adhesive on the floating body and to decompose the foaming plastic or reduce its volume.

Description

Hollow ball type fluidized bed microbial carrier for wastewater treatment and odor removal {A METHOD OF MANUFACTURING EGG SHELL TYPE MEDIA FOR BIOLOGICAL WASTEWATER TREATMENT AND OFFENSIVE ODOR REMOVAL}

The present invention relates to a method for producing a fluidized bed microbial carrier in the form of a hollow ball for wastewater and water treatment and for removing odors. More specifically, the present invention provides a method for producing a fluidized bed microbial carrier for a biofilter that can be applied to various conditions such as an anaerobic tank, aeration tank, and a filtration tank to remove odors such as hydrogen sulfide or ammonia gas by adjusting specific gravity.

In general, biologically treated wastewater / wastewater can be divided into activated sludge process and biofilm process.

In the case of activated sludge process, it is not only susceptible to fluctuations in water quality and quantity, it is difficult to treat high and low concentrations, and there is a problem in that a large amount of sludge is generated at a temperature change, especially at low temperatures, and frequent sludge swelling occurs.

On the other hand, the biofilm method has a high concentration of microorganisms attached to the carrier, and excellent in removal efficiency for contaminants, it is possible to preserve the low growth rate microorganisms in the carrier. In addition, stable ecosystems and micro-animals are properly distributed, which prevents sludge swelling and shows stable removal efficiency even at high / low concentration loads. In addition, the amount of sludge generated is small and the size of the reactor can be greatly reduced.

Microbial immobilization carriers used in the biofilm process are roughly classified into polymer, ceramic or activated carbon carriers, while carriers are also classified into fixed and fluidized bed carriers.

In the case of installing the carrier in the stationary phase, the removal efficiency of the contaminants can be increased by appropriate arrangement such as horizontally in the form of bed or vertically in the form of sheet, but it is expensive to install, difficult to repair or dismantle, and there is a problem in further expansion. In addition, as the sludge is deposited, there is a problem that the pressure is increased and the flow of the fluid is not smooth.

On the other hand, the fluidized bed carrier does not require any installation cost, and by adding an additional carrier, the fluidized bed carrier can flexibly cope with the treatment capacity and there is no possibility of clogging of the media. In addition, the fluidized bed carrier has many advantages in terms of facility cost and process follow-up compared to the fixed bed carrier.

Polymeric carriers are inexpensive and can be manufactured in a desired shape, but are convenient, but have a small specific surface area, are physically / chemically unstable, and frequently cause desorption of immobilized microorganisms, as well as a large amount of sludge.

On the other hand, ceramic-based carriers have a disadvantage that the specific surface area is large and physically / chemically stable, the microbial film is thinly formed, and the sludge generation amount is small, but the production of the desired carrier is difficult and manufactured by high temperature baking. In addition, there is a disadvantage that loses the adsorptive properties of the clay surface due to high temperature firing. Activated carbon carriers are mainly limited to organic material adsorption / decomposition applications.

In order to solve this problem, a fluidized bed carrier having a cage structure and capable of inserting a specific gravity control object is provided in Korean Patent Publication No. 96-9384, but it is difficult and complicated to manufacture. By inserting the polymer-based microbial contact agent physically / chemically unstable microorganisms are frequently detached, there is a disadvantage that does not have the microorganism-friendly properties of the clay-based ceramic carrier.

In addition, Korean Patent Publication No. 97-26944 proposes a fluidized bed carrier manufacturing technology in which a porous styrene carrier, which has a foamed styrene rod placed in its center and a freeze-dried strain, is filled around the rod and wrapped in a net. In addition, this carrier is also not easy to manufacture and has a mesh shape so that the fluid does not flow smoothly to the inside, resulting in low efficiency.

Korean Patent Publication No. 98-074499 discloses a carrier in which fine activated carbon is attached to a porous polyurethane foam with an acrylic resin adhesive. However, this carrier initially floats in water and has a problem of sinking after a month or more due to the attachment of sludge.

Korean Patent Publication No. 98-9145 introduces a biological deodorization method of an anaerobic treatment tank in a sewage treatment apparatus using a carrier such as polyurethane foam and porous ceramics, but it is limited to a form in which the carrier is suspended on the top of the anaerobic treatment tank of the sewage treatment apparatus. have.

Accordingly, an object of the present invention is to provide a hollow microbial carrier production method for preparing a clay-based active support material as a fluidized bed carrier.

Another object of the present invention is to provide a method for producing a hollow microbial carrier having excellent removal efficiency of contaminants.

1 is a cross-sectional view showing a variety of internal floating (support) forms,

2 is a cross-sectional view showing a floating body coated with an active support material,

Figure 3 is a cross-sectional view showing the form of the final carrier with a specific gravity is adjusted as a portion of the inner support after firing.

Description of simple symbols in the drawing

1 .... suspended solids with foamed plastic particles 2 .... active support

3 .... hollows formed inside the carrier upon firing

According to one aspect of the invention,

(1) coating an adhesive and an active support material on a floating body made of expanded plastic particles having a specific gravity of 1.0 g / cm 3 or less; And

(2) primary firing such that the adhesive of the floating body coated with the adhesive and the active support material is cured and the foamed plastic is decomposed or reduced in volume;

Wastewater treatment and odor removal in the form of hollow hollow balls

Methods of making a phase microbial carrier are provided.

Hereinafter, with reference to the accompanying drawings the present invention will be described in detail.

The fluidized bed microbial carrier manufacturing method of the present invention consists of coating an adhesive and an active support material on a float and then firing it.

In the present invention, as the floating body 1, a foamed plastic is used. More specifically, the foamed plastic is made of polystyrene (PS), polyethylene (PE), polypropylene (PP), and mixtures thereof.

As the floating body used as the support of the active support material, as shown in Figure 1 can be used in various forms, such as circular, square, oval and triangle, most of which is spherical. As the floating body, a foamed plastic having a specific gravity of 1 g / cm 3 or less is used. In the hollow microbial carrier of the present invention, a foamed plastic having a specific gravity of 1 g / cm 3 or less is used to be suspended in water in a fluidized bed and flowed according to the flow of water.

The active supporting material is coated on the foamed plastic float as described above through an adhesive. In this case, the adhesive and the active support material may be sequentially coated on the float and then fired, or the adhesive and the active support material may be mixed and then coated on the float. 2 is a view showing a cross section of a floating body (support) made of expanded plastic particles coated with an active support material.

In the case of sequentially coating the adhesive and the active support material on the float, the adhesive is first coated on the foamed plastic float, and then the active support material is coated on the adhesive.

As the adhesive, a polymer organic resin adhesive and an inorganic resin adhesive are used.

Polyurethane resins, epoxy resins, phenol resins, acrylic resins, and the like may be used as the polymer organic resin adhesives, and silica sol, water glass, and ceramic adhesives may be used as the inorganic adhesives.

As the active support material (2), one or more supported materials selected from the group consisting of powdery clay, activated carbon, coke, steel mill waste slag, volcanic ash, and combustion materials may be used. As clays, zeolite, vermiculite, diatomaceous earth, etc. may be used. , Kaolin, pottery, feldspar, octopus, talc.

As described above, the active support material used in the present invention is not only good for microorganisms to inhabit but also catalyzes the activity of microorganisms during water treatment by microorganisms. This is further increased.

It is preferable to use an active support substance: adhesive at a weight ratio of 60 to 95:40 to 5. If the adhesive is used at less than 5 wt%, some of the active supporting material is released from the water and if used in excess of 40 wt%, not only adversely affects the adsorption capacity of the carrier or the ability to adhere to the microorganisms but also the carrier price is too expensive. .

In addition, the active support material may be optionally added to, mixed with sawdust or crushed small foamed plastic particles and / or other pore control agents and coated on the floating body and calcined to form gaps or pores in the microbial carrier.

As such, by forming gaps or pores in the microbial carrier, water freely enters into and out of the hollow ball through the pores, thus maintaining microorganisms at a high concentration in the hollow ball carrier, thereby improving the removal efficiency of contaminants.

Other pore control agents include inorganic salts such as ammonium carbonate and ammonium nitrate, and organic high molecular materials such as ethylene glycol, cellulose and starch.

The pore control agent should be 30 or less, based on the total weight of the mixture of the active support and the adhesive. If it is used in excess of 30, the strength is lowered and it is inappropriate in terms of economics.

After coating the adhesive and the active support material on the float as described above, by firing it to prepare a fluidized bed microbial carrier.

Firing temperature and firing time depend on the type of adhesive used, the size of the hollow required and the specific gravity of the microbial carrier required.

Furthermore, after the first firing, the firing step may be repeated secondly or thirdly without coating or coating an adhesive and an active support material on the hollow ball-type fluidized bed microbial carrier prepared by primary firing as needed. .

By primary firing, the adhesive is cured in the floating body coated with the adhesive and the active supporting material to act as a binder, while the expanded plastic floating body is decomposed or reduced in volume to form a hollow inside the carrier.

Therefore, the primary firing temperature and time are carried out at a time and temperature sufficient to cause the adhesive to cure and decompose the foamed plastic float, and for 5 minutes to 5 hours at a temperature of about 80 to 150 ° C. By firing at such a primary firing temperature, the adsorption capacity of the active ingredient in the active support material due to high temperature firing is not lowered and manufacturing costs can be relatively reduced.

As the floating body coated with the adhesive and the active support material, a hollow 3 is formed as shown in FIG. 3.

Microorganisms or waste water may enter the hollow 3 formed by the firing and cause a reaction. In addition, the specific gravity of the microorganism carrier can be controlled by controlling the size of the foamed plastic suspension inside the carrier according to the firing temperature. The hollow ball-type microbial carrier thus prepared has a much more frequent contact with contaminants by fluid flow and maintains microorganisms at a high concentration in the hollow fire, thus exhibiting much better pollutant removal efficiency.

If the microbial carriers formed after the first firing do not exhibit sufficient strength or need to adjust their specific gravity, the microbial carriers formed by the primary firing may be coated with an adhesive and an active support material sequentially or without coating or coating these mixtures. Secondary firing can be performed at temperatures higher than the secondary firing temperature. If the thickness of the active support material film is about 1 mm or more, it is considered to exhibit sufficient strength. If necessary, the coating and firing can be repeated.

Furthermore, in the case of high-temperature firing at a temperature of 900 ° C. or higher after the first low-temperature firing, it is preferable to use clays such as kaolin, feldspar, and pottery soil having good bonding strength. On the other hand, the high-temperature fired microbial carriers can be used as microbial carriers for wastewater / wastewater and water treatment, odor removal biofilters, and also chromium (Cr), platinum (Pt), The carrier may be manufactured by coating vanadium (V) and the like, and the carrier supported with chromium, platinum, vanadium, and the like may also be used as a fluidized bed catalyst for hot gas.

For example, in the case of using an organic adhesive, the foamed plastic coated with the active support material is first baked at 100 ° C. or lower, and the second is calcined at a temperature of 100 ° C. or higher to evaporate and shrink the foamed plastic. The hollow 3 is formed.

More specifically, when an epoxy resin is used as the adhesive, the adhesive is partially cured at a firing temperature of 100 ° C. or less, and the foamed plastic coated with the active support material becomes hard while maintaining a round shape. Above 100 ° C, partial decomposition and condensation of the foamed plastics occurs. When firing at 110 ° C. for 20 minutes, some of the floating body is reduced to about 3/4 size, and some of the foamed plastic expands and bursts into a spider web in the carrier. In the case of firing at 130 ° C. for 20 minutes, the size of the foamed plastic is reduced to 1/3 or less to form a large amount of empty space. After firing at 150 ° C for 20 minutes, the hollow ball is almost completely empty.

As such, by forming an empty space in the carrier, microorganisms can be maintained / held therein, and the inside of the carrier is also used for the reaction when treating pollutants, so that the amount of the active support material is much smaller than that of the conventional granule carrier. Not only can it be produced with a carrier having a specific surface area, but it is also superior in economy and its functionality.

The hollow ball-type microbial carrier thus formed is a fluidized bed microbial carrier having a total specific gravity of 0.5 to 1.1 g / cm 3.

The fluidized bed microbial carrier of the hollow hollow ball shape produced by the present invention has excellent adaptability at high concentration loads and excellent ability to remove organic matter, nitrogen and phosphorus, and is applied under various conditions such as anaerobic tank, aeration tank and filtration tank.

In addition, it can be applied to high concentration organic wastewater or hardly degradable wastewater, and also to air pollution field such as odor removing biofilter such as hydrogen sulfide or ammonia gas.

Furthermore, when the microbial carriers having different specific gravity (0.5 to 1.1 g / cm 3) prepared in the present invention are put in a cage such as a cage and put into an anaerobic tank or aeration tank, an appropriate flow of the fluid flows up and down occurs to increase efficiency. Blocking of the media can be prevented.

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

<Example 1>

After coating a water-soluble epoxy resin on a foamed plastic (styrofoam) having a diameter of 4 to 6 mm, it is placed in an active supporting material mixed with 60 weights of zeolite, 30 weights of slag and 10 weights of activated carbon, and a ball coater is used. By coating. The above materials are all powdery (100 mesh or more).

After the adhesive and the active support material coated floating body was cured for 8 minutes at 90 ℃ and coated with a mixture of epoxy resin (including hardener) and water in a ball coater containing the mixed active support material.

The resultant was calcined at 110 ° C. for 20 minutes to prepare a hollow ball-type microbial carrier having foamed plastic crushed to about 3/4. The specific gravity of the prepared carrier was 0.6-0.8 g / cm 3.

After filling the carrier with about 30 in a 250 cm 3 aeration tank, synthetic wastewater of 150 ppm COD and 25 ppm NH ₄ ⁺ -N (ammonia nitrogen) was kept for 4 hours. After 4 hours, the COD removal rate was 95 and the nitrification rate was 83.

<Example 2>

The ball coater was used to re-coat the adhesive and the active support material on the microbial carrier prepared in 1, and then calcined at 130 ° C. for 20 minutes to prepare a carrier. In this case, the size of the expanded plastic suspension was reduced to less than one third, and the specific gravity of the microbial carrier was 0.8 to 1.0 g / cm 3.

The COD removal rate and nitrification rate were measured in the same manner as in Example 1, and the COD removal rate was 96 and the nitrification rate was 83.

<Example 3>

A carrier was prepared in the same manner as in Example 2, except that the material was calcined at 150 ° C. for 30 minutes. In this case, the foamed plastics were completely decomposed and completely formed hollow balls. The hollow ball had a specific gravity of 0.8 to 1.0 g / cm 3, similar to that of Example 2.

As a result of measuring the COD removal rate and nitrification rate in the same manner as in Example 1, the COD removal rate was 96 and the nitrification rate was 84.

<Example 4>

60 weight of zeolite, 30 weight of slag, and 10 weight of coke were mixed, and the active support material was produced, and the microbial carrier of the hollow ball form was prepared as in Example 3. In this case, the foamed plastics were almost disappeared, and the specific gravity of the microbial carrier was 0.8-1.1 g / cm 3, similar to that of Example 3.

The COD removal rate and nitrification rate were measured in the same manner as in Example 1, and the COD removal rate was 94 and the nitrification rate was 85.

<Example 5>

A microbial carrier was prepared in the same manner as in Example 2, except that the active support material was mixed with 3 weights of sawdust and 2 weights of crushed small foamed plastic particles. In this case, the clearance, porosity and roughness of the hollow ball carrier were much increased, and the specific gravity was about 0.7 to 0.9 g / cm 3, and the COD removal rate and nitrification rate were 97 and 84, respectively.

<Example 6>

A microbial carrier was prepared in the same manner as in Example 2 except that the polyurethane resin was used as the adhesive.

In this case, the COD removal rate and nitrification rate measured in the same manner as in Example 1 were 94 and 83, respectively.

<Example 7>

40 wt% zeolite, 30 wt% slag, and 30 wt% diatomaceous earth were mixed to make an active supporting material, and a hollow ball was prepared in the same manner as in Example 2. In this case, the COD removal rate and nitrification rate measured in the same manner as in Example 1 were 95 and 84, respectively.

<Example 8>

40 wt% zeolite, 30 wt% kaolin, and 30 wt% diatomaceous earth were mixed to make an active support material, and coated with a thicker layer to maintain strength. Then, ceramic hollow ball microbial carrier was prepared by tertiary firing at 1100 ° C. In this case, the COD removal rate and nitrification rate measured in the same manner as in Example 1 were 95 and 84, respectively.

<Example 9>

20 ppm ammonia gas was flowed at 5-10 L / min in a reactor having a size of 120 mm x H 1000 mm, and the ammonia gas was removed using the microbial carrier prepared in Example 5. The ammonia gas removal rate of 95-99 was shown.

<Example 10>

20 ppm ammonia gas was flowed into a reactor having a size of 120 mm x H 1000 mm at a rate of 5 to 10 l / min, and the ammonia gas was removed using the carrier prepared in Example 8. The ammonia gas removal rate of 96-99 was shown.

<Comparative Example 1>

In the aeration tank described in Example 1 using a polyurethane porous sponge carrier, the COD removal rate and nitrification rate were 85 and 71, respectively.

<Comparative Example 2>

In the aeration tank described in Example 1 using a sponge-type carrier coated with activated carbon, the COD removal rate and nitrification rate were 87 and 74, respectively.

Specific gravity (g / cm 3) Porosity () COD removal rate Nitrification rate Example 1 0.6-0.8 74 and above 95 83 Example 2 0.8-1.0 76 and above 96 83 Example 3 0.8-1.0 Over 81 96 84 Example 4 0.8-1.1 80 or more 94 85 Example 5 0.7-0.9 82 or more 97 84 Example 6 0.7-1.0 78 or more 94 83 Example 7 0.6-1.0 Over 79 95 84 Example 8 0.7-1.1 83 or more 95 84 Comparative Example 1 0.035-0.040 95 or more 85 71 Comparative Example 2 0.115-0.211 93 and above 87 84

As can be seen in Table 1, the fluidized bed microbial carrier prepared by the method according to the present invention exhibits excellent pollutant removal performance.

Hollow ball-type fluidized bed microbial carrier prepared by the present invention has excellent adhesion state of microorganisms compared to polymer carriers, and the thickness of microbial membrane is as thin as ceramic carrier, and the specific surface area is wide and physical / chemically stable against the growth of microorganisms. Do.

In addition, microorganisms grow in high concentrations in the hollow ball over a long period of time, so it is stable against fluctuations in the flow rate of the flow and wastewater, and has a high efficiency in removing pollutants, and when used in a filtration tank, By preventing the outflow, the quality of the final effluent can be further improved.

Furthermore, it is possible to maintain / grow microorganisms at a much higher concentration than conventional carriers, and thus it is applicable to high concentration organic wastewater or hardly degradable wastewater treatment.

In addition, it is possible to install odor removal biofilters in ultra / wastewater treatment plants, sludge treatment and other chemical plants that may cause odor.

Claims (12)

(1) coating an adhesive and an active support material on a floating body made of expanded plastic particles having a specific gravity of 1.0 g / cm 3 or less; And (2) primary firing such that the adhesive of the floating body coated with the adhesive and the active support material is cured and the foamed plastic is decomposed or reduced in volume; Wastewater treatment and odor removal in the form of hollow hollow balls Phase microbial carrier manufacturing method The method of claim 1, further comprising the step of secondary firing such that the expanded plastic is decomposed and evaporated and the volume of the carrier is reduced without coating or coating an adhesive and an active support material on the primary calcined microbial carrier. How to. The method according to claim 1 or 2, wherein the firing is carried out at a temperature of 80 to 150 DEG C for 5 minutes to 5 hours. The method of claim 1, wherein the floating support is coated with an active support material after the coating. The method of claim 1, wherein the floating body is coated with a mixture of an adhesive and an active support material. The method of claim 4 or 5, wherein the active support material and the adhesive are used in an amount of 60 to 95:40 to 5 weight ratio. The method of claim 1 wherein the float is foamed plastic and is made of polystyrene, polyethylene, polypropylene, and mixtures thereof. The method of claim 1, wherein the adhesive is a polymer organic resin selected from polyurethane resins, epoxy resins, phenol resins, acrylic resins or inorganic resins selected from silica sol, water glass and ceramic adhesives. The method of claim 1, wherein the active support material is selected from powdered clay, activated carbon, coke, steel mill waste slag, volcanic ash, and combustion ash. 10. The method of claim 1, 4, 5 or 9, wherein the active support material and optionally the pore control agent is mixed to a floating body by mixing up to 30 wt. And / or form pores. The method of claim 10, wherein the pore control agent is inorganic salts such as sawdust, expanded plastic particles, ammonium carbonate and ammonium nitrate and organic polymers such as ethylene glycol, cellulose and starch. The method according to claim 1 or 10, characterized in that the microorganisms are maintained or cultured in the hollow carrier microbial carrier.