KR100425245B1 - Carrier For Immobilization Of Microorganisms Based On Scoria And The Preparation Method Thereof - Google Patents

Abstract

The present invention relates to a microorganism carrier used for wastewater treatment and a method for producing the same. Specifically, the present invention provides a carrier for wastewater treatment based on a scoria (aka, cluster), and coated with a cationic polymer thereon, and a method of manufacturing the same. The present invention also provides a microorganism-immobilized carrier having a microorganism immobilized thereon, a wastewater treatment system and a wastewater treatment method using the same. The microorganism carrier of the present invention has the advantage of attaching a high concentration of microorganisms by the complex action of physical properties such as porosity and chemical properties of PEI Korea can be used very effectively for biological treatment of wastewater. In addition, the carrier carrier of the present invention can be effectively installed on the inner wall of the river, the embankment of the bank or the bottom of the river, such as to effectively induce the natural purification of wastewater.

Description

Carrier for Immobilization of Microorganisms Based On Scoria And The Preparation Method Thereof}

The present invention relates to a microorganism carrier used for wastewater treatment and a method for producing the same. Specifically, the present invention relates to a microorganism carrier for wastewater treatment based on scoria (aka, cluster), and prepared by coating a cationic polymer thereon.

Wastewater treatment methods include physical, chemical and biological methods. As physical wastewater treatment, mixing, precipitation, filtration and distillation are used. Chemical wastewater treatment includes chemical precipitation using alum, sterilization using chlorine compounds, heavy metals, phenolic compounds, carbon dioxide, adsorption using activated carbon, and ultraviolet (UV) / There is a photooxidation method using ozone. Activated sludge process and tickling filter process are widely used for biological wastewater treatment.

Among them, the biological treatment method is mainly suitable for the treatment of wastewater containing a large amount of organic compounds, and is a method of decomposing organic matter in urban sewage or industrial wastewater by microorganisms. Depending on the need for oxygen, it is divided into aerobic processes and anaerobic processes, which are further classified into suspended growth processes and attached growth processes. The most commonly used biological treatment method is the activated sludge process which is an aerobic process and suspended growth process. Activated sludge is a method in which microorganisms and wastewater are suspended in an aeration tank so that the microorganisms decompose organic substances in the wastewater. However, since this method has a low microbial concentration in the aeration tank, when a high concentration of wastewater is introduced, there is a disadvantage in that the load of organic matter is increased and the microbial activity is rapidly decreased. Therefore, the waste water treatment time is increased and the cost of oxygen supply in the aeration tank is increased and it is economically disadvantaged (Bitton, G., "Wastewater Microbiology", John Wiley Sons, INC., New York, pp. 89-198, NY (1994)).

In order to solve this problem, an adhesion growth process has been developed to maintain microorganisms at high concentrations, and this means that a group of microorganisms capable of organic decomposition is applied to solid surfaces such as stones, slags, ceramics or plastics. It refers to the process of treating wastewater by adhering. This is also known as a fixed-film process. In this case, a contact material such as ceramic used to attach or fix microorganisms is called a carrier. Currently, many ceramic and plastic carriers are used. Polymeric carriers such as plastics, although economical, have a small specific surface area and have disadvantages of being disposed of after use. In addition, some polymer materials have a water swelling property, so that they are easily broken during use. In contrast, ceramic-based carriers have a relatively large specific surface area and are physically and chemically stable, but they are not easy to manufacture (Park Jae-gu, Lee Tae-kyung, Jung Young, "Ceramic Support for Wastewater Treatment", Cera Mist, Vol. 3, No. 6, pp.11. -19 (2001)).

Accordingly, the present inventors have recognized the above problems and researched a more convenient and efficient microbial carrier, and found that when a cationic polymer material was coated on volcanic rock material scoria, high concentrations of microorganisms could be efficiently fixed. This invention was completed.

The present invention provides a microorganism carrier coated with a cationic polymer in Scoria and a method for producing the carrier.

The present invention provides a microorganism-immobilized carrier in which microorganisms are immobilized on the skore carrier.

The present invention provides a system for treating wastewater by using the SKOREA microorganism-immobilized carrier and a wastewater treatment method using the same.

The present invention provides a microbial carrier coated with a cationic polymer in Scoria. Specifically, the scaly carrier is a microbial carrier having various useful features such as porosity, stability, durability, and economics, and is coated with a cationic polymer PEI (polyethyleneimine) on the scaly.

Scoria is a type of volcanic products. When magma erupts on the surface, it loses gas and becomes lava, which contains some gas after the outflow, and they collect on the surface of the lava flow to form pores called vesicles. Particularly, many pores and pale to white are called pumice, and rock fragments similar in volume to two pores and solids are called scoria.

There is also a lot of sea Korea called Jeju as volcanic eruptions on Jeju Island. Jeju Island on Jeju Island is a volcanic rock material that contains volcanic rock, volcanic sand and other volcanic ashes. About 75% of the components of SK Korea are silicon oxide (SiO ₂ ), aluminum oxide (Al ₂ O ₃ ) and iron oxide (Fe ₂ O ₃ ), and calcium oxide (CaO), magnesium oxide (MgO) and potassium oxide. (K ₂ O), sodium oxide (Na ₂ O), nickel oxide (TiO ₂ ), and the like.

The shape of the sea Korea is porous, and its specific surface area is about 100m ² / g and relatively large, thus providing a good environment for microorganisms to grow. In addition, S Korea has physical and chemical and biological stability, high mechanical strength and durability, there is an economic advantage that can be used to collect natural materials.

The process of forming a biofilm by attaching microorganisms to the surface of the carrier is a complex process in which many factors work together. The biofilm formation process is not yet clearly understood, but in general, the characteristics of the carrier (porosity and surface area, surface roughness, chemical properties, particle size, concentration, etc.), the characteristics of the microorganisms (type, cell age, concentration, culture, suspension) Media, surface chemical properties, etc.) and environmental properties (pH, temperature, ionic strength, hydraulic properties, contact time, etc.) has been reported (Jeong, Jae-chun, "Microbiological aspects of biofilms, Korean Society of Environmental Engineering, 16 (5), pp. 1-12 (1994)) S Korea used as a material of the present invention is a material having excellent physical properties such as porosity, surface area and surface roughness among the properties of the carrier.

On the other hand, the electrical charge of the cell surface is generated by the electrical dissociation of the amino group (-NH ₂ ) and the carboxyl group (-COOH), the electrical charge state is affected by the pH of the solution. If the pH of the solution is lower than the isoelectric point (the pH value when the microbial surface is not electrically charged), the carboxyl group remains unionized but the amino group is ionized to NH ₃ ⁺ , resulting in a positive charge of the microorganisms. On the contrary, when the pH of the solution is higher than the isoelectric point, the microorganisms are negatively charged because the amino group is not ionized and the carboxyl group is ionized with COO ⁻ . Since the isoelectric point of the microbial surface is in the acid range of pH 4-5, most microorganisms in nature are negatively charged. An electrostatic attraction is applied between the surface of the positively charged medium and the microorganisms so that the microorganisms can attach relatively easily to the positively charged medium.

Accordingly, the inventors of the present invention made it possible to easily attach the microorganism group to the carrier by coating the cationic polymer material on the basis of the above. Cationic polymer materials that can be coated on the present invention include chitosan, DEAE-dextran (DEAE, Dextran) in addition to polyethylene imine (PEI). The cationic polymer of the present invention is preferably PEI (polyethyl eneimine). PEI is a polymer with a water soluble surface. PEI is a cationic polymer composed of a -NH functional group having an adsorption property to various oxides and a -CHx (x = 1,2) functional group having an adsorption property with respect to organic compounds, and has an advantage that it is harmless to microorganisms and the human body. In the present invention, the molecular weight of PEI used in the examples is about 750,000, which was purchased from Sigma (USA).

The present invention provides a method for producing a carrier coated with PEI, a cationic polymer, in Scoria. SK Korea can use the ones collected from nature by size or use them without any distinction of size. It is preferable to use it separately by size, and at this time, various physical separation methods, for example, separation by size such as sieve separation may be used. In the embodiment of the present invention, the size of the scoop is 3-14 mesh, preferably 4-8 mesh. The concentration of the cationic polymer for coating should be sufficient to coat the carrier. In general, the preferred coating concentration is 5 to 500 mg / L. When using a PEI solution, the concentration is suitably 20 to 100 mg / L and preferably adjusted to 30 to 40 mg / L. The carrier was immersed in a cationic polymer, for example, a PEI solution, and then dried at high temperature in Korea. Immersion time is enough in 30 minutes-2 hours.

In the case of biological wastewater treatment in a septic tank, it is common to use activated sludge, which is a collection of various microorganisms contained in the wastewater, rather than supplying specific microorganisms to the microbial source due to the nature of the wastewater.

The above-mentioned active sludge is a sludge containing aerobic bacteria and various protozoa in aeration tanks in general sewage treatment plants, including metabolites such as Pseudomonas, which are decomposed nitrates with nitrite or ammonia. Bacteria such as the genus Zoogloea, a genus of aerobic bacteria, Nocardia genus, Bdellovibrio genus, and Mycobacterium genus. Species and carnivores Sarcodina, plant flagellar Phyto flagellates, animal flagellar zoo flagellates, bloodsucking insect Suctoria, and cilia Protozoa such as Stalked cilliates.

The microorganisms can be immobilized on the carrier by contacting the activated sludge with the carrier of the present invention prepared by coating a cationic polymer, for example, PEI, on SKOREA. The time taken to immobilize the microorganisms varies depending on the temperature, the type of activated sludge, etc., but in the case of using the scaly carrier of the present invention, it is common to combine the physical characteristics such as porosity possessed by the scaly and the chemical characteristics by PEI. There is an advantage that the immobilization time is shorter than the carrier. Accordingly, the present invention provides a microorganism-immobilized carrier in which microorganisms are immobilized on the skore carrier.

The present invention provides a system for treating wastewater using the Sukyong carrier and a wastewater treatment method using the same. In the case of using the scaly carrier of the present invention, immobilization time can be shortened by excellent porosity (skorea) and microbial adhesion (PEI) to increase the microbial adhesion amount and COD removal rate within a short time. Chemical Oxygen Demand (COD) measured in an embodiment of the present invention is a representative water pollution indicator that represents the amount of oxygen consumed when a pioxid in water, especially an organic material, is treated by an oxidizing agent, and the amount of microbial adhesion is attached to the carrier unit mass. By the total amount of microorganisms is meant the ability of the carrier to adhere to the microorganisms.

The concentration of PEI coated for wastewater treatment was most preferably 30-40 mg / L. Within the scope of the following examples, the COD removal rate was the highest when the carrier was used as a carrier having a particle size of 4-8 mesh, but the carrier particle size did not significantly affect the microbial adhesion amount and the COD removal rate (Table 3).

Sea Korea carrier of the present invention can be usefully used in the form of aeration tank and fixed-bed in the wastewater treatment facilities using microorganisms, such as sewage and sewage treatment plants, industrial and livestock wastewater treatment plants. Sea Korea, the carrier material of the present invention, is a natural resource readily obtainable in large quantities. Therefore, in order to use the carrier of the present invention in a wastewater facility of a limited space as well as to show its applicability in a natural space, a method of purifying the carrier by installing it on the ground of a river or the like and embankment of the inner wall or bank of the river The method of purifying wastewater by attaching it with epoxy resin or the like was tested. When the scaly carrier of the present invention is installed at the bottom of the stream and purged, and attached to the wall of the flow path to purify it, the short residence time of 1.5 hours and 0.5 hours, respectively, is 68-85% and 42-46%, respectively. The COD removal rate was obtained. Therefore, it was confirmed that both the method of purifying the carrier by installing it on the bottom of a river and the method of purifying the wastewater by attaching it to the inner wall of the river or the embankment of the bank are effective.

Hereinafter, the present invention will be described in more detail with reference to Examples. However, the following examples are illustrative of the present invention, and the content of the present invention is not limited by the examples.

<Example>

Example 1

Preparation of SKO Korea Coated with PEI

SKOREA was sifted by size using a sieve of 3, 4, 10, 14 mesh (mesh). The separated S Korea was immersed in 35 mg / L PEI solution (Sigma) at room temperature for 1 hour or more and coated with PEI. PEI-coated sea Korea was dried for 24 hours at 105 ℃ to prepare a PEI-coated sea Korea carrier.

Example 2

COD removal rate and microbial adhesion amount measurement

The COD removal rate and microbial adhesion amount of the microorganism carrier of the present invention prepared in Example 1 were investigated. Sukko carrier of 3-4 mesh size was put in the aeration tank so that the filling rate is 40%, and the wastewater was introduced. At this time, the residence time of the wastewater was 4 hours, and the COD removal rate and microbial adhesion amount were measured after 4 days of operation. As the influent wastewater, synthetic wastewater having the composition shown in Table 1 was used. The microorganism used for immobilization was activated sludge. The activated sludge is collected at the sewage treatment plant in Jeju. Activated sludge was adapted with constant supply of medium and air at room temperature and used for this experiment after at least two weeks of adaptation.

COD (chemical oxygen demand) was determined according to standard process tests. Determination of the amount of microorganisms attached to the s Korea was by the following method. After the experiment is finished, the scrim is washed with 0.85% (w / v) NaCl solution and dried at 100-105 ° C. for 1 hour, and then the cells attached to the scrim are detached with 0.5 N NaOH solution. The NaOH solution from which the cells were detached was dried in an oven at 100 to 105 ° C., and then the dry weight was measured. From this, the weight of NaOH used for desorption was subtracted and expressed as the weight per unit mass of the carrier (mg / g). The results are shown in Table 2.

Composition of Synthetic Wastewater Furtherance Chemical formula Concentration (mg / L) glucose C ₆ H ₁₂ O ₆ 1,000 Ammonium Sulfate (NH ₄ ) ₂ SO ₄ 250 Magnesium sulfate MgSO _{4 7} H ₂ O 102.3 Iron chloride FeCl ₃ · 6H ₂ O 0.42 Calcium chloride CaCl ₂ 3.75 Manganese sulfate MnSO ₄ H ₂ O 5.6 Potassium Hydroxide K ₂ HPO ₄ 70.5 1M Sodium Hydroxide NaHCO ₃ 5 mL / L

Comparative example

COD removal rate and microbial adhesion measurement of SKO Korea carrier without PEI coating

The waste water treatment capacity (COD removal rate and microbial adhesion amount) of SKOREA without PEI coating was compared with the case of wastewater treatment ability (Example 2) of PEI coated SKIA carrier. After filling the 3 ~ 4 mesh size of SKorea without filling the PEI so that the filling rate is 40%, the wastewater was introduced in the same manner as in Example 2, and then the COD removal rate and microbial adhesion amount were measured. The experimental results are shown in Table 2.

In the case of using SEIKO coated with PEI of the present invention as a carrier, the amount of microbial adhesion increased by about twice as much as using the same amount of ceramic and SKOREA showed high COD removal rate. Therefore, it was found that SKO Korea coated with PEI exhibited better wastewater treatment than that without PEI coding (Table 2).

COD removal rate and microbial adhesion amount of the carrier of the present invention carrier % COD removal after 1 day of operation % COD removal after 4 days Amount of adhesion (mg / g) Example 2 PEI Coatings Korea 81 97 29.4 Comparative example S Korea 72 93 17

Example 3

Wastewater Treatment Capacity of SKO Korea Carrier Installed on the Base of Euro Channel

The 3-4 mesh sized carrier carrier (100 g) prepared in Example 1 was laid on the bottom of a flow path made of acrylic material having a width of 3 cm and a length of 50 cm, and 500 mL of activated sludge was continuously circulated for 2 days to attach microorganisms to the carrier. Thereafter, the synthetic wastewater was supplied so that the residence time was 1.5 hours. After 4 days of operation, the COD removal rate and microbial adhesion amount were measured according to the method of Example 2. The results are shown in Table 3. The measured microbial adhesion amount and COD removal rate were high, and it was confirmed that even when the carrier of the present invention was laid on the bottom of the river, the microorganisms were easily attached to the carrier and thus had a natural purification effect.

Example 4-9

Comparison of Wastewater Treatment Capacity with Carrier Size and PEI Concentration

PEIs having concentrations of 20, 50 and 100 mg / L, respectively, were coated on the SKOREA having a size of 3 to 4 mesh in the same manner as in Example 1. In addition, carriers were prepared by coating with PEI having a concentration of 35 mg / L in SKOREA having sizes of 4 to 8 mesh and 10 to 14 mesh, respectively. COD removal rate and microbial adhesion amount of the prepared carrier were measured (Table 3).

When the mesh sizes were the same, the amount of microbial adhesion and COD removal were the highest when the SKO coated with PEI solution concentration of 35 mg / L was used as a carrier. The COD removal rate was highest when the carrier was used as a carrier having a particle size of 4-8 mesh. However, the carrier particle size did not significantly affect the microbial adhesion amount and the COD removal rate (Table 3).

COD removal rate and microbial adhesion according to carrier size and PEI concentration PEI concentration (mg / L) Carrier mesh % COD removal after 4 days Amount of adhesion (mg / g) Example 4 35 3-4 83 33.4 Example 5 20 3-4 68 24.5 Example 6 50 3-4 79 30.9 Example 7 100 3-4 76 29.4 Example 8 35 4-8 85 34.1 Example 9 35 10-14 83 32.9

Example 10

COD removal effect of carrier adhered to flow path

100 g of a carrier having a size of 3 to 4 mesh prepared in Example 1 was bonded to the bottom and the wall of an acrylic channel having a width of 3 cm and a length of 100 cm with an epoxy resin. 500 mL of activated sludge was continuously circulated for 2 days to attach microorganisms to the carrier, and then, synthetic wastewater was supplied so that the residence time was 0.5 hour, and the COD removal rate was measured after 1, 2, 3, and 4 days of operation. The results are shown in Table 4.

Despite the relatively short residence time, the COD removal rate was around 44%, confirming that the wastewater was effectively purified (Table 4).

COD removal rate of Skori carrier bonded to the bottom and wall of the flow path Operating hours (days) COD removal rate (%) One 42 2 46 3 44 4 43

SukKorea used as a material of the present invention is an unused resource scattered in large quantities throughout Jeju Island, as well as abundant in the amount of pore, specific surface area and surface roughness has a characteristic that microorganisms are easy to attach. The scaly carrier of the present invention is to add the chemical properties of PEI to the physical properties such as porosity of the score, and when using the scaly carrier of the present invention, the acclimation time is shortened to increase the microbial adhesion and COD removal rate. Could.

The carrier carrier of the present invention can be usefully used as a wastewater treatment system using microorganisms in wastewater treatment facilities such as sewage and sewage treatment plants, industrial and livestock wastewater treatment plants, and the carrier is attached to the inner walls of rivers or banks of embankments. It can be used or installed on the bottom of river, etc., to effectively induce natural purification of wastewater.

Claims (7)

Carrier for wastewater treatment coated with polyethyleneimine on volcanic rock scoria particles. delete The carrier according to claim 1, wherein the scaly particle size is 3 to 14 mesh. Sieving the sKOREA by size; Immersing the scoria in a PEI solution having a concentration of 20 to 100 mg / L for 30 minutes to 2 hours; And drying the dipped sea Korea. Brick with the carrier of claim 1 or 3 A method of treating wastewater using the carrier of claim 1 or 3 or the brick of claim 5. The method of claim 6, wherein the carrier or brick is installed on the bottom and / or inner wall of the stream to treat the wastewater.