KR102530855B1 - Sewage and wastewater treatment carrier and manufacturing method thereof - Google Patents

Abstract

The present invention relates to a method for manufacturing a carrier for sewage and wastewater treatment with greatly improved purification performance. The present invention includes the steps of: preparing raw materials including 100 parts by weight of sludge, 30 to 50 parts by weight of blast furnace slag, 20 to 40 parts by weight of clay, 10 to 20 parts by weight of vermiculite, and 1 to 10 parts by weight of ceramic fibers based on 100 parts by weight of the sludge; preparing a mixed raw material composition by mixing the raw materials and a sodium silicate solution; preparing a molded product obtained by molding the mixed raw material composition; and sintering the molded product.

Description

Sewage and wastewater treatment carrier and manufacturing method thereof

The present invention relates to a method for manufacturing a carrier for treatment of sewage and wastewater with greatly improved purification performance.

Activated sludge is currently widely used in domestic sewage and wastewater treatment. Activated sludge is a generic term for microorganisms used in biological treatment of sewage and wastewater treatment plants. As a general method of the activated sludge method, there is a standard activated sludge method centered on BOD removal, which is modified to simultaneously remove nitrogen and phosphorus. There is a biological advanced treatment method.

The advanced biological treatment method is largely divided into a suspended growth method and an adherent growth method. The floating growth method is a method of contacting and treating microorganisms and sewage by performing agitation and aeration, and the adherent growth method is a method using a carrier to which microorganisms can adhere.

Recently, the development of the attached growth method for use in the floating growth method has been actively carried out. As the microbial carrier filled in the aeration tank increases the contact surface area with the microorganisms to increase the amount of microorganisms attached, eventually hydraulic It has the advantage of shortening the residence time. Moreover, since the microbial carrier can be introduced without large-scale remodeling of existing treatment facilities, treatment efficiency can be improved at a minimum cost.

Such microbial carriers are generally classified into organic carriers such as polyvinyl chloride, polyethylene, polyurethane, etc., and inorganic carriers such as porous zeolite, granular activated carbon, and ceramics, depending on their material. In order to do this, progress has been made mainly in the direction of increasing porosity, specific surface area and surface roughness.

Republic of Korea Patent No. 10-1492833 Republic of Korea Patent No. 10-0759833 Republic of Korea Patent Publication No. 10-2011-0084706 Republic of Korea Patent Publication No. 10-2004-0068824

The present invention has been made to solve the problems of the prior art, and an object of the present invention is a carrier for treating sewage and wastewater, which has a structure capable of attaching a large amount of microorganisms to the surface and can greatly improve purification performance, and manufacture thereof is to provide a way

The problem to be solved by the present invention is not limited to those mentioned above, and other problems not mentioned will be clearly understood by those skilled in the art from the description below.

In order to achieve the above object, the method for manufacturing a carrier for sewage and wastewater treatment according to the present invention includes 100 parts by weight of sludge, 30 to 50 parts by weight of blast furnace slag based on 100 parts by weight of the sludge, 20 to 40 parts by weight of clay, Preparing a raw material containing 10 to 20 parts by weight of vermiculite and 1 to 10 parts by weight of short fibers;
preparing a mixed raw material composition in which the raw material and a sodium silicate solution are mixed;
preparing a molded article obtained by molding the mixed raw material composition;
Including; firing the molding;
The sludge is a pulp sludge containing 35 to 45% by weight of iron oxide on a carbide basis, and the short fiber is a molten compound of aluminum oxide (Al ₂ O ₃ ) and silicon dioxide (SiO ₂ ) processed to a thickness of 0.1 to 1 μm. has done,
The firing of the molding is characterized in that it is performed for 2 to 7 hours at a temperature of 1,000 to 1,200 ° C.

In addition, in the method for preparing a carrier for sewage and wastewater treatment according to the present invention, the raw material and the sodium silicate solution are mixed in a weight ratio of 1: 0.2 to 0.5.

In addition, in the method for manufacturing a carrier for sewage and wastewater treatment according to the present invention, the molding is characterized in that it has a spherical or cylindrical structure.

In addition, in the method for manufacturing a carrier for sewage and wastewater treatment according to the present invention, the firing of the molded product is characterized in that it is performed at a temperature of 1,000 to 1,200 ° C for 2 to 7 hours.

The carrier for treating sewage and wastewater and the manufacturing method according to the present invention has a structure capable of attaching a large amount of microorganisms to the surface and has an effect of significantly improving purification performance.

The effects of the present invention are not limited to those mentioned above, and other effects not mentioned will be clearly understood by those skilled in the art from the description below.

Hereinafter, preferred embodiments of the present invention will be described in detail.

In describing the present invention, if it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the gist of the present invention, the detailed description will be omitted. In addition, terms to be described later are terms defined in consideration of functions in the present invention, which may vary according to the intention of a user or operator or a precedent. Therefore, the definition should be made based on the contents throughout this specification.

The carrier for sewage and wastewater treatment according to the present invention relates to a biological carrier capable of significantly increasing the treatment efficiency by greatly increasing the attachment of microorganisms and promoting the activity of microorganisms.

The method for manufacturing a carrier for sewage and wastewater treatment according to the present invention comprises 100 parts by weight of sludge, 30 to 50 parts by weight of blast furnace slag, 20 to 40 parts by weight of clay, and 10 to 20 parts by weight of vermiculite based on 100 parts by weight of the sludge. Step S1 of preparing a raw material including 1 to 10 parts by weight of ceramic fiber, step S2 of preparing a mixed raw material composition obtained by mixing the raw material and a sodium silicate solution, and S3 step of preparing a molded article obtained by molding the mixed raw material composition And, it may be made including a step S4 of firing the molding.

The sludge may be exemplified by wastewater sludge, sewage sludge or purified water sludge having a water content of 5 to 20%. Among them, wastewater sludge containing a large amount of iron oxide can be exemplified by pulp sludge or sludge generated in a dyeing factory. It has the advantage of greatly improving adsorption performance. For reference, the carbonized material obtained by carbonizing the pulp sludge contains about 35 to 45% by weight of iron oxide, which is a significantly larger amount compared to the iron oxide content of 4 to 6% by weight in the sludge of the water treatment plant.

The blast furnace slag is generated in the blast furnace of the steelmaking process, and is limitedly used as a component such as cement additives and crushed bone agents according to characteristics, and is recently used in various fields such as building materials and ceramic materials, and silica 30 to 36% , alumina 12~18%, iron oxide (Fe ₂ O ₃ ) 0.25~0.35%, calcium oxide (CaO) 38~45%, magnesium oxide (MgO) 10.0% or less, sulfur oxide (SO ₃ ) having a composition of 4.0% or less It is known.

The ceramic fiber is, for example, made of a molten compound of aluminum oxide (Al ₂ O ₃ ) and silicon dioxide (SiO ₂ ) in the form of a fiber, and is a single fiber having a thickness of 0.1 to 1 μm to widen the specific surface area of the carrier. Preferably, it also serves to reinforce the decrease in strength of the carrier due to the addition of feldspar having a brittle property.

The clay serves to provide adhesion during molding and firing, and when it is less than 20 parts by weight, it is difficult to sufficiently exhibit adhesion or binder performance, and when it exceeds 40 parts by weight, the content of sludge or slag, which is a recycled component, is lowered, resulting in a large manufacturing cost It rises and the increase in strength compared to the excess amount is not large, so it is preferable to limit it to the above-mentioned range.

In the present invention, vermiculite is added together with clay, and vermiculite expands during firing to form micropores.

If the vermiculite is less than 10 parts by weight, expansion or bubble formation is not sufficiently achieved, and if it exceeds 20 parts by weight, it is relatively excessively contained compared to other components, so physical properties such as strength are significantly reduced. It is desirable to limit

In step S2 of the present invention, the raw material and the sodium silicate solution are preferably mixed at a weight ratio of 1: 0.2 to 0.5. When the weight ratio of the sodium silicate solution is less than 0.2, it is difficult to sufficiently exhibit foaming performance and adhesive strength, If it is exceeded, it is preferable to limit it to the above-mentioned range because it can be mixed relatively excessively when compared with the raw material and rather block the pores.

The sodium silicate solution of the present invention contains 60-70 parts by weight of water in 30-40 parts by weight of water glass having the specifications of KS-3 (9-10% by weight of Na ₂ O, 28-30% by weight of SiO ₂ and the remaining amount of water) A mixture was used.

Step S3 of the present invention is to prepare and dry a molded product by molding the mixed raw material composition, and the molded product may have a spherical or cylindrical structure with a diameter of 10 to 30 mm, but is not limited thereto.

Step S4 of the present invention is a step of forming a carrier by firing the molding, and may be exemplified by firing at a temperature of 1,000 to 1,200 ° C. for 2 to 7 hours.

When the firing temperature is less than 1,000 ° C., pores are not formed due to expansion of vermiculite, and when it exceeds 1,200 ° C., sodium silicate solution components are fused to block pores, so it is preferable to limit it to the above-described temperature range.

Hereinafter, a method for manufacturing a lightweight porous ceramic sintered body using vermiculite according to the present invention will be described in more detail through a preferred embodiment.

S1. Raw materials including 100 parts by weight of wastewater sludge, 40 parts by weight of blast furnace slag, 30 parts by weight of clay, 20 parts by weight of vermiculite, and 5 parts by weight of ceramic fibers are prepared.

S2. Prepare a mixed raw material composition in which the raw material and the sodium silicate solution are mixed in a weight ratio of 1:0.3.

S3. The mixed raw material composition is molded to dry a spherical molding having a diameter of 20 mm.

S4. The spherical molding was calcined in an electric furnace at a temperature of 1,050 ° C. for 3 hours to prepare a carrier, and then immersed in a Bacillus liquid spawn for 6 hours.

[Comparative Example 1]

A carrier was prepared in the same manner as in Example 1 except that 100 parts by weight of sewage sludge was used instead of wastewater sludge, 55 parts by weight of clay was used, and vermiculite and ceramic fibers were omitted.

[Comparative Example 2]

A carrier was prepared in the same manner as in Comparative Example 1, except that water was used instead of the sodium silicate solution in Comparative Example 2.

[Test Example 1]

In order to measure the degree of denitrification and dephosphorization, total nitrogen and total phosphorus were quantitatively analyzed in the inflow and outflow wastewater before and after being introduced into the treatment tank equipped with the carrier. It was measured, and the removal rate was obtained using this.

1. Ammonia nitrogen: Ammonia nitrogen was quantitatively analyzed using the phenate method, and 0.4 mL of phenol solution and 0.4 mL of sodium nitroprusside solution per 10 mL of sample (inflow and outflow sewage) , After adding 1.0 mL of an oxidizing agent, the color was developed in a place where light was blocked for about 1 hour, and ammonia reacted with sodium nitropurside under the catalyst of hypochlorite and phenol to obtain blue indophenol. is formed and it was measured with a 640 nm spectrophotometer.

2. Nitrite nitrogen: Quantitative analysis was performed using a calometric method, and 50 mL of the sample (influent/sewage) was calibrated with HCl or NaOH so that the pH was between 5 and 9, and the calibrated sample was N-(1- Naphthyl)-ethylenediamine dihydrochloride (N-(1-naphthyl)-ethylenedia mine dihydrochloride: NED) reagent 1 mL was added, and the color was developed for 10 minutes, and the absorbance was measured at 543 nm using a spectrophotometer within 2 hours. did

3. Nitrate nitrogen: Quantitative analysis was performed using a UV-spectrophotometric screening method, and 1 N HCl solution was added to 25 mL of the sample (inflow and outflow sewage) to adjust the pH of the sample to be between 2 and 3. Absorbance at 220 nm and 275 nm was measured using a UV-visible spectrophotometer, respectively. The measured value was substituted into the formula of A 220 nm - 2 (A 275 nm), and the actual concentration of nitrate nitrogen was quantitatively analyzed.

4. Total nitrogen: As a result of quantitative analysis after oxidizing all nitrogen components in the sample (inflow and outflow sewage) to nitrate using the persulfate method, 5 mL of digest ion reagent was added per mL of sample After heating in an autoclave for 30 minutes, the nitrogen component of the sample is oxidized in the form of nitrate, which was quantified using the nitrate measurement method.

5. Phosphate: Quantitative analysis was performed using the Stannous chloride method, 1 mL of molybdate reagent and 2 drops of Stannous chloride reagent in 20 mL of sample (inflow and outflow sewage) When added, the Stanyus chloride reagent reacts with phosphorus phosphate in the sample to form a blue precipitate, which was quantified using a 690 nm UV-visible spectrophotometer. At this time, since the color reaction differs depending on the temperature and time, the absorbance was measured exactly between 10 and 12 minutes after the Stanley's chloride reagent was added at room temperature.

6. Total phosphorus: Quantitative analysis was performed using the persulfate digestion method. A drop of phenolphthalein indicator was added to 50mL of the sample (inflow and outflow sewage), and when a red color appeared, sulfuric acid solution was added to make it colorless. , 1 mL of sulfuric acid solution was additionally added, and 0.5 g of potassium persulfate was added thereto and heated in an autoclave for 30 minutes to digest. Phosphate phosphorus was analyzed according to the quantitative analysis method.

7. Biochemical Oxygen Demand (BOD): Put samples (inflow and outflow sewage) in three BOD bottles, and use the azide modification method in one of the bottles to determine the initial amount of dissolved oxygen (DO initial) was measured, and the other two bottles were placed in an incubator at 20 ° C and incubated for 5 days in the absence of light, and the final dissolved oxygen amount (DO final) was measured. ) was measured. In the azide modifica tion method, add 1 mL each of manganous sulfate solution and alkali-iodide-azide reagent to the sample contained in the BOD bottle, then shake. Upon mixing, a brown precipitate was formed. When the precipitate sank halfway, 1 mL of concentrated sulfuric acid solution was added and shaken to dissolve completely. Pour 200 mL of this sample into another flask and add a few drops of starch solution as an indicator to blue When a color appeared, it was titrated until it became colorless with a thiosulfate titrant, and at this time, the amount of dissolved oxygen (mg/L) of the sample was obtained by the amount of the titrant used.

8. Chemical Oxygen Demand (COD) is defined as the amount of oxygen consumed when organic matter in water is chemically oxidized, and the unit is expressed as mg/L. In this experiment, open reflux ) method was used, and the method was to first put 50 mL of sample (inflow and outflow sewage) into a 500 mL reflux flask, add 1 g of mercuric sulfate, slowly add 5 mL of sulfuric acid reagent, cool it, and , After adding 25 mL of potassium dichromate solution and 70 mL of sulfuric acid reagent, connect a condenser with an open end, boil in a heater for 2 hours, cool, ferroin ( After adding 0.15 mL of the ferroin indicator, the titration was performed with a ferrous ammonium sulfate (FAS) titrant, and the amount of titrant consumed at this time was substituted into Equation 1 below to calculate the chemical oxygen demand (mg / L) did

[Equation 1]

Chemical Oxygen Demand = (Amount of FAS used in the blank test - Amount of FAS used in the sample) * moles of FAS

Concentration * 8000 (conversion factor) / sample volume (mL)

9. Suspended solids (SS): After filtering distilled water with a filter paper (glass fiber filter, 90 mm dia., 0.7 um pore size) to be used first, drying in a dryer at 103 to 105 ° C for a certain period of time, and then drying it in a sulfuric acid desiccator Cool and weigh, then filter a certain amount of sample with filter paper, dry it in a dryer for a certain period of time, and then measure the weight according to the previous method. (mg/L) was measured.

The test results obtained according to the above test method are shown in Table 1 below.

Removal rate (%) Example 1 Comparative Example 1 Comparative Example 2 SS 96.2 73.9 68.2 BOD 95.4 71.5 65.3 COD 92.0 68.4 64.9 total nitrogen 89.1 65.2 61.8 total phosphorus 88.9 59.7 55.5

In Table 1 above, the average influent is 60.1 (mg/L) and the average outlet is 4.2 (mg/L).

Referring to Table 1 above, it was confirmed that the carrier according to the present invention had significantly higher removal rates for SS, BOD, COD, total nitrogen and total phosphorus when compared to Comparative Examples 1 and 2.

The present invention described above is only exemplary, and those skilled in the art will appreciate that various modifications and equivalent other embodiments are possible therefrom. Therefore, it will be well understood that the present invention is not limited to the forms mentioned in the detailed description above. Therefore, the true technical protection scope of the present invention should be determined by the technical spirit of the appended claims. It is also to be understood that the present invention includes all modifications, equivalents and alternatives within the spirit and scope of the present invention as defined by the appended claims.

Claims (5)

Preparation of raw materials including 100 parts by weight of sludge, 30 to 50 parts by weight of blast furnace slag, 20 to 40 parts by weight of clay, 10 to 20 parts by weight of vermiculite, and 1 to 10 parts by weight of short fibers based on 100 parts by weight of the sludge step of doing;
preparing a mixed raw material composition in which the raw material and a sodium silicate solution are mixed;
preparing a molded article obtained by molding the mixed raw material composition;
Including; firing the molding;
The sludge is a pulp sludge containing 35 to 45% by weight of iron oxide on a carbide basis, and the short fiber is a molten compound of aluminum oxide (Al ₂ O ₃ ) and silicon dioxide (SiO ₂ ) processed to a thickness of 0.1 to 1 μm. has done,
Method for producing a carrier for sewage and wastewater treatment, characterized in that the firing of the molding is performed at a temperature of 1,000 to 1,200 ° C. for 2 to 7 hours.
According to claim 1,
The method of manufacturing a carrier for sewage and wastewater treatment, characterized in that the raw material and the sodium silicate solution are mixed in a weight ratio of 1: 0.2 to 0.5.
According to claim 1,
The method of manufacturing a carrier for sewage and wastewater treatment, characterized in that the molding has a spherical or cylindrical structure.
delete A carrier for sewage and wastewater treatment, characterized in that it is produced by the method of any one of claims 1, 2 and 3.