KR100596366B1 - Hydrophilic immobilized media for immobilizing microbe for the wastewater treatment and manufacturing method thereof - Google Patents

Abstract

A hydrophilic microorganism immobilization carrier for wastewater treatment, the carrier comprises a polyethylene glycol polymer of three-dimensional network structure in which crosslinking is formed between a polyethylene glycol polymer molecule backbone formed by polymerization of a polyethylene glycol component. In addition, the microorganisms to purify the waste water is immobilized and the waste water is provided with a plurality of pores that can enter and exit, the pores are extended to each other to form a reticulated network of flow channels (reticulated network of flow channels) A hydrophilic microorganism immobilization carrier and a method of manufacturing the same are disclosed. The hydrophilic microorganism immobilization carrier according to the present invention is not toxic to wastewater treatment microorganisms, and microorganisms can be efficiently encapsulated in large quantities, and has a network flow path having a network structure formed therein, so that material diffusion is well performed. Therefore, wastewater can be efficiently treated by biological methods.

Description

Hydrophilic immobilized media for immobilized media for immobilizing microbe for the wastewater treatment and manufacturing method

FIG. 1 shows the change in the degree of mass diffusion with respect to the center of each carrier in a carrier that does not contain a slurry, 0.5% nitrifier and 0.5% activated sludge carrier (0.5% Ad. AS carrier).

Figure 2 shows the change of mass diffusion rate with time at the center of 0.5% Ad.AS carrier before and after wastewater treatment.

3 shows surface SEM pictures (2,000 magnification) of the PEG carriers of Examples 1 to 10, and FIGS. 3A to 3J are surface SEM pictures of the PEG carriers of Examples 1 to 10, respectively.

FIG. 4 shows a PEG-1 carrier immediately after synthesis using the sorbitol crosslinking agent of Example 1, a WET SEM photograph of the PEG-1 carrier immediately after immobilization of nitrifying bacteria, and an operation for about 70 days after immobilization. The WET SEM or SEM photograph of the following PEG-1 carrier is shown.

Figure 5a shows the results of the nitrification treatment efficiency test of PEG-1 carrier immobilized ammonia nitrogen load over time and 0.5% and 1% nitrification bacteria.

Figure 5b records the change in ammonia nitrogen concentration of the influent, the reactor filled with 0.5% nitrifying immobilized PEG-1 carrier, and the reactor filled with 1.0% nitrifying immobilized PEG-1 carrier over time.

The present invention relates to a hydrophilic microorganism immobilization carrier and a method for producing the same, and more particularly, to a hydrophilic microorganism immobilization carrier capable of effectively treating sewage and wastewater by a biological method by comprehensively fixing and decomposing strains of organic substances to be treated, and a method of manufacturing the same. It is about.

One of the contaminants contained in sewage and waste water (hereinafter referred to simply as "waste water") is organically biodegradable organics (Slowly or Hardly Biodegradable Organics). And Non Biodegradable Organics. Biodegradable organic material is an organic material that can be easily decomposed by ordinary microorganisms, and hardly decomposable organic material is an organic material that can be decomposed by microorganisms but takes a long time to decompose due to a slow decomposition rate. It means organic matter.

Hardly decomposable organic matters are generally treated by physical and chemical methods, and if they can be treated with specific microorganisms, it is preferable because they can reduce a lot of costs for physical and chemical treatments. In particular, since dyeing wastewater and paper mill wastewater contain many hardly decomposable organic substances, there have been attempts to treat such dyeing wastewater by biological methods rather than physicochemical methods.

However, the microbial suspension method represented by the activated sludge method, which is still widely used among biological treatment methods, has a drawback problem in that it is difficult to accumulate microorganisms that decompose organic matters at a high concentration in the reaction tank due to the serious problem of leakage from the reaction tank of the microorganisms.

Therefore, a biological treatment method using a biofilm carrier has attracted attention as a technique capable of effectively decomposing organic matter. Examples of biological treatment methods using a biofilm carrier include a biofilm method, a comprehensive fixation method, and a self-assembly method. In particular, the comprehensive immobilization method can immobilize a specific microorganism or enzyme in a high concentration in a carrier, and thus the treatment efficiency is high, and biological treatment of hardly degradable organic substances such as dyeing wastewater or papermaking wastewater is also possible, and sludge generation can be expected to be attracting attention. have. The comprehensive fixation method also has a strong advantage against fluctuations in the external environment such as water quality, quantity, temperature and concentration.

However, even in the above-mentioned immobilization method, it is not toxic to microorganisms used for decomposition of organic matter, and it is essential to develop a carrier having excellent mechanical properties and durability.

Accordingly, the technical problem of the present invention is to provide a hydrophilic microorganism immobilization carrier capable of efficiently encompassing and immobilizing various microorganisms such as nitrifying microorganisms and denitrification microorganisms.

Another technical problem of the present invention is to provide a method for preparing the hydrophilic microorganism immobilization support.

One embodiment of the present invention to achieve the above technical problem,

Hydrophilic microbial immobilization carrier for wastewater treatment, the carrier,

Poly (ethylene glycol) acrylate, poly (ethylene glycol) diacrylate, poly (ethylene glycol) methacrylate, poly (ethylene glycol) dimethacrylate, poly (ethylene glycol) divinyl ether, poly (ethylene glycol) At least one polyethylene glycol component selected from the group consisting of ethyl ether methacrylate, poly (ethylene glycol) methyl ether acrylate, poly (ethylene glycol) methyl ether methacrylate, and poly (ethylene glycol) phenyl ether acrylate It comprises a polyethylene glycol polymer of the three-dimensional network structure is cross-linked between the polymer molecule backbone formed by polymerization,

In addition, the microorganisms to purify the waste water is immobilized, and the waste water is provided with a plurality of pores that can enter and exit, the pores are extended to each other to form a reticulated network of flow channels (reticulated network of flow channels) A hydrophilic microbial immobilization carrier is provided.

Another embodiment of the present invention to achieve the above another technical problem,

As a method for producing a hydrophilic microorganism immobilization carrier,

(a) in a reaction vessel in which an aqueous solvent and a polymerization initiator are present, the polyethylene glycol component and the crosslinking agent are mixed and stirred to polymerize the polyethylene glycol component and form crosslinks between the polymer backbones of the polyethylene glycol component. Forming a polyethylene glycol polymer of a network structure;

(b) neutralizing the polyethylene glycol polymer solution to adjust the pH of the solution in the range of 6 to 8 and converting the polymer solution into a gel state; And

(c) extruding the gelled polyethylene glycol polymer solution to obtain a carrier having a plurality of pores extending from each other to form a reticulated network of flow channels. to provide.

The hydrophilic microorganism immobilization carrier according to the present invention is not toxic to wastewater treatment microorganisms, and microorganisms can be efficiently encapsulated in large quantities, and have a network structure of a reticulated network of flow channels (reticulated network of flow channels) formed therein. Diffusion works well. Therefore, wastewater containing a large amount of hardly degradable organic matter such as dyeing wastewater and papermaking wastewater can be efficiently treated by biological methods. In addition, the hydrophilic immobilized carrier according to the present invention has sufficient compressive strength and elasticity so that it can be used for long-term wastewater treatment. The hydrophilic immobilized carrier according to the present invention is also excellent in thermal properties and poorly soluble in organic solvents and thus can be used for long-term wastewater treatment.

Hereinafter, the hydrophilic microorganism immobilization support of the present invention and a method of manufacturing the same will be described in detail.

First, the hydrophilic microorganism immobilization carrier of the present invention will be described.

Hydrophilic microbial immobilization support for wastewater treatment according to an embodiment of the present invention, the polyethylene glycol component is a polyethylene glycol polymer of a three-dimensional network structure crosslinking is formed between the backbone (polymer) formed by polymerizing the polyethylene glycol component It features.

The polyethylene glycol component is not particularly limited as long as the polyethylene glycol unit is bonded to at least one ethylenically unsaturated group having a polymerization capability such as vinyl group, acrylate group, and the like, and specific examples thereof include poly (ethylene glycol) acrylate and poly (ethylene glycol). ) Diacrylate, poly (ethylene glycol) methacrylate, poly (ethylene glycol) dimethacrylate, poly (ethylene glycol) divinyl ether, poly (ethylene glycol) ethyl ether methacrylate, poly (ethylene glycol) methyl Ether acrylate, poly (ethylene glycol) methyl ether methacrylate, poly (ethylene glycol) phenyl ether acrylate and the like.

The polymerizable ethylenically unsaturated group such as the acrylate group is polymerized by the initiator to have a molecular weight sufficient for the polymer to form a carrier, and the polystyrene glycol unit imparts sufficient hydrophilicity to the carrier so that the microorganism is easily encapsulated and immobilized. Play a role.

On the other hand, a polymer obtained by polymerizing only the polyethylene glycol component alone or mixed may also function as a carrier, but forming a three-dimensional network structure in which hydrophilic crosslinks are formed between the polymer molecular backbones may include microorganism inclusion, durability, and elasticity. It is preferable in terms of the increase.

The hydrophilic crosslinking is obtained by forming an intermolecular or intramolecular crosslinking between a polystyrene glycol polymer molecule by a crosslinking agent containing 1 to 6 functional groups. The crosslinking agent which can be used in the present invention for this purpose is sorbitol, N, N'-diallyl tardiamide, N, N'-methylenebisacrylamide, diallyl fumarate, 1,5-hexadien-3-ol Or a mixture thereof. In addition to N, N'-methylenebisacrylamide, trimethylolpropane triacrylate, di (ethylene glycol) diacrylate, triallyl 1,2,4-benzenetricarboxylate, diallylamine, tetraallyloxyethane, Divinylbenzene, diallyl phthalate, and the like have also been tested as crosslinking agents, but are not preferred in terms of durability, toxicity to microorganisms, and the like.

The content of the crosslinking is preferably formed by reacting 4 to 6 parts by weight of the crosslinking agent based on 100 parts by weight of the polyethylene glycol component. If the content of the crosslinking agent is less than 4 parts by weight, there is a problem in that the strength of the carrier is weakened.

The carrier of the present invention also has many pores extending from one another to form a reticulated network of flow channels. Microorganisms for treating wastewater are fixed and fixed in these pores, and the wastewater diffuses in and out through the passage in the pores.

Microorganisms that can be immobilized in the carrier of the present invention include Pseudomonas putida and Pseudomonas aerosol, which can treat not only conventional nitrifying bacteria, denitrifying bacteria, organic matter removing microorganisms, but also wastewater containing a large amount of hardly degradable organic substances such as dyeing wastewater and papermaking wastewater. Microorganisms, such as Ginosa, Pseudomonas sp, Pseudomonas alkalicans, Bacillus, etc. are mentioned.

The carrier of the present invention is also preferably further equipped with a boron-oxygen bond by reacting with sodium tetraborate decahydrate in terms of elasticity increase and the like.

Next, the manufacturing method of the hydrophilic microorganism immobilization support of this invention is demonstrated in detail.

First, in a reaction vessel in which an aqueous solvent and a polymerization initiator are present, the polyethylene glycol component and the crosslinking agent are mixed and stirred to polymerize the polyethylene glycol component and form crosslinks between the polymer backbones of the polyethylene glycol component. To form a polyethylene glycol polymer.

As the aqueous solvent, water, methanol, or a mixed solvent of ethanol and water may be used, but it is preferable to use water in view of economical efficiency and solvent recovery. This polymerization can proceed even at relatively high temperatures of 50 to 60 ° C. or higher, but it is preferable to further add an accelerator so that the polymerization of the polyethylene glycol component can proceed at room temperature. As such accelerators, N, N, N ', N'-tetramethylethylenediamine, β-methylamide propionitrile and the like may be used. However, N, N, N', N'-tetramethylethylenediamine in terms of economical efficiency Preference is given to using.

The use ratio of the polyethylene glycol component and the crosslinking agent is preferably 4 to 6 parts by weight of the crosslinking agent is mixed based on 100 parts by weight of the polyethylene glycol component. The reason is as described above. If the amount of the crosslinking agent is less than 4 parts by weight, there is a problem that the strength of the carrier is weakened. If the amount of the crosslinking agent is more than 6 parts by weight, the gel is formed too quickly.

The total concentration of the polyethylene glycol component and the crosslinking agent in the solvent is preferably adjusted to 15 to 21% by weight. If the total concentration is less than 15% by weight, there is a problem of insufficient carrier strength. If the total concentration is more than 21% by weight, the carrier strength is increased, but the viscosity of the reaction product is increased so that the substrate permeability in the carrier is lowered and the activity of the microorganism is decreased. There is a problem.

When the polyethylene glycol component and the crosslinking agent are mixed and stirred in this manner, the polymerization reaction of the polyethylene glycol component and the intermolecular and intramolecular crosslinking between the growing polymer and the crosslinking agent occur simultaneously, and as a result, a crosslinked polymer having a three-dimensional network structure is formed. At this time, it is preferable to further add sodium tetraborate decahydrate in order to increase the elasticity of the obtained polymer carrier. This will react with the crosslinker portion of the growing polymer and sodium tetraborate decahydrate to produce boron-oxygen bonds that increase the elasticity of the carrier.

The polymerization reaction is completed by stirring for about 1 minute after the polyethylene glycol component, the crosslinking agent, and the accelerator are all mixed. The stirring speed is not particularly limited, but usually about 600 rpm to about 1,200 rpm is sufficient.

Subsequently, the polyethylene glycol polymer solution is neutralized to adjust the pH of the solution in the range of 6 to 8, thereby converting the neutralized polymer solution into a gel state. At this time, after adjusting the pH of the polymer solution in the range of 6 to 8, it is possible to effectively encapsulate the predetermined microorganisms in the pores in the carrier by injecting and aging the sludge containing the microorganisms to be encapsulated immobilized in the reaction vessel. When the neutralized polymer solution is filled into a sealed container and aged for a predetermined time in an incubator at room temperature, the solution changes state from sol state to gel state and is suitable for extruding.

Extrusion of the gelled polyethylene glycol polymer solution through an appropriate diameter orifice provides a carrier having a plurality of pores extending from one another to form a reticulated network of flow channels. The extrusion is carried out by pushing the gel polymer solution into the air or into an aqueous solution containing inorganic salts such as sodium sulfate, zinc sulfate and sodium chloride. The extruded carrier is in the form of a filament or a rod, and the desired carrier can be obtained by cutting the pellet into a predetermined length and pelletizing it.

As described above, the incorporation and immobilization of the microorganism is preferably performed in the aspect of continuity, ease, etc. of the process after the polymer polymerization and before the extrusion process, but after completion of the carrier shape by the extrusion process, the carrier is left in the sludge containing the microorganism for a certain period of time. Microorganisms can also be encapsulated and fixed within the pores.

Hereinafter, the present invention will be described in more detail with reference to Examples. This is for illustrating an embodiment of the present invention, and the scope of the present invention is not limited by the embodiment.

 Example 1 Synthesis of PEG-1 Carrier

First, 180 g (161 ml) of polyethylene glycol diacrylate aqueous solution (MIWON Corporation, 18 w / v%, trade name: MIRAMER M286) in water 740 ml, aqueous solution of potassium persulfate as an initiator (Dongyang Steel Chemical, 0.25 w / v) %) 2.5 g was added to the reactor, and the reactor was stirred at 600 rpm for 3 minutes to polymerize.

Subsequently, 9 g of sorbitol aqueous solution (Dongyang Chemical Co., Ltd., 0.9w / v% aqueous solution), which is a crosslinking agent, was stirred for 1 minute, and sodium tetraborate decahydrate (Dongyang Steel Chemical, STB, 0.16 w / v%) 1.6 g of aqueous solution, and 2.5 g of N, N, N ', N'-tetramethylethylenediamine (Shinyo Corp., 0.25 w / v% aqueous solution), which are accelerators for enabling radical polymerization at room temperature, are further added. Input. Subsequently, an appropriate amount of 10% acetic acid solution was mixed and the pH of the polyethylene glycol diacrylate was neutralized in the range of 6 to 8 so as to be suitable for the living environment of the microorganisms to be later supported as a carrier, followed by nitrifying sludge containing nitrifying bacteria. Or activated sludge containing several microorganisms and stirred uniformly for about 30 seconds. The resultant adjusted in this way was filled in a PVC tube using a syringe and aged for about 10 minutes in a 25 ℃ thermostat. During the aging process, the sol reaction product is solidified in a gel state, and is extruded using a syringe to obtain a cylindrical solidified polymer gel carrier having a diameter of about 4 mm, which is cut at intervals of 4 mm to form a PEG carrier (PEG-1). Carrier).

The concentration of the immobilized microorganisms was 0.5% (w / v) or 1.0% (w / v). If the MLSS concentration of the sludge was 5000 mg / l, the mixture was concentrated to 10 ml by centrifugation and mixed at neutral pH conditions.

 Example 2 Synthesis of PEG-2 Carrier

A PEG carrier (PEG-2 carrier) was obtained in the same manner as in Example 1, except that 10 g of N, N'-diallyl tardiamide (Aldrich, 1 w / v%) was used instead of sorbitol as a crosslinking agent. .

 Example 3 Synthesis of PEG-3 Carrier

A PEG carrier (PEG-3 carrier) was obtained in the same manner as in Example 1 except that 10 g of N, N'-methylenebisacrylamide (Aldrich, 1 w / v%) was used instead of sorbitol as a crosslinking agent.

 Example 4 Synthesis of PEG-4 Carrier

A PEG carrier (PEG-4 carrier) was obtained in the same manner as in Example 1 except that 10 g of diallyl fumarate (Aldrich, 1 w / v%) was used instead of sorbitol as a crosslinking agent.

 Example 5 Synthesis of PEG-5 Carrier

A PEG carrier (PEG-5 carrier) was obtained in the same manner as in Example 1 except that 10 g of 1,5-hexadien-3-ol (Aldrich, 1 w / v%) was used instead of sorbitol as a crosslinking agent. .

 Example 6 Synthesis of PEG-6 Carrier

A PEG carrier (PEG-6 carrier) was obtained in the same manner as in Example 1 except that sodium tetraborate decahydrate (STB), which was an elastic modifier, was not used.

 Example 7 Synthesis of PEG-7 Carrier

A PEG carrier (PEG-6 carrier) was obtained in the same manner as in Example 2 except that sodium tetraborate decahydrate (STB), which was an elastic modifier, was not used.

 Example 8 Synthesis of PEG-8 Carrier

A PEG carrier (PEG-8 carrier) was obtained in the same manner as in Example 3 except that sodium tetraborate decahydrate (STB), which was an elastic modifier, was not used.

 Example 9 Synthesis of PEG-9 Carrier

A PEG carrier (PEG-9 carrier) was obtained in the same manner as in Example 4 except that sodium tetraborate decahydrate (STB), which was an elastic modifier, was not used.

 Example 10 Synthesis of PEG-10 Carrier

A PEG carrier (PEG-10 carrier) was obtained in the same manner as in Example 5 except that sodium tetraborate decahydrate (STB), which was an elastic modifier, was not used.

Table 1 PEG carrier composition ratio

Polyol component Crosslinking agent Elastic reinforcement Initiator accelerant Kinds Usage (g) Kinds Usage (g) Kinds Usage (g) Kinds Usage (g) Kinds Usage (g) Example 1 MIRAMER M286 180 Sorbitol 9 Sodium Tetraborate Decahydrate (STB) 1.6 Potassium persulfate 2.5 N, N, N ', N'-tetramethylethylenediamine 2.5 Example 2 " " N, N'-diallyl tardiamide " " " " " " " Example 3 " " N, N'-methylenebisacrylamide " " " " " " " Example 4 " " Diallyl fumarate " " " " " " " Example 5 " " 1,5-hexadiene-3-ol " " " " " " " Example 6 " " Sorbitol " - - " " " " Example 7 " " N, N'-diallyl tardiamide " - - " " " " Example 8 " " N, N'-methylenebisacrylamide " - - " " " " Example 9 " " Diallyl fumarate " - - " " " " Example 10 " " 1,5-hexadiene-3-ol " - - " " " "

 Compressive strength measurement

Compressive strength is one of the important factors that determine the service life as a measure of the durability of the carrier. Therefore, the change of compressive strength according to the presence or absence of STB, an elastic modifier of PEG carrier, was measured.

Compressive strength was measured using SMS (Stable Micro Systems) Texture Analyser (TA-XT2). That is, the average value of compressive strength was calculated by randomly selecting 10 PEG carriers cut at intervals of 4 mm for cylindrical carriers having an inner diameter of 4 mm at random in the state of containing water. The compressive strength was obtained from the following equation.

F = P / S

Where F is the compressive strength, P is the load (N) when the carrier starts to rupture, and S is the cross-sectional area of the carrier under load (0.1257 cm 2).

Table 2 summarizes the compressive strength measurement results for the PEG carriers obtained in Examples 1 to 10.

(Table 2) Compressive strength change according to crosslinking agent type and elastic reinforcing agent type

Compressive strength (kg / cm2) Example 1 4.869 Example 2 5.978 Example 3 3.782 Example 4 4.983 Example 5 3.152 Example 6 3.978 Example 7 4.067 Example 8 6.285 Example 9 4.162 Example 10 3.346

Referring to Table 2, it can be seen that all of the carriers of Examples 1 to 10 had sufficient compressive strength regardless of whether STB was included. Among them, Examples 1 to 5, in which STB was included in the molecular structure, were generally used. In the case of Examples 6 to 10 it can be seen that the increased compressive strength. In particular, it can be seen that the compressive strength is excellent when N, N'- diallyl tar tarimide (Example 2), diallyl fumarate (Example 4), and sorbitol (Example 1) are used as the crosslinking agent. . The inventors found that addition of STB affects elasticity as well as durability.

 Mass Diffusion Measurement

The diffusion of material into the carrier is one of the important characteristics of the carrier. This is because oxygen diffusion increases into the carrier containing microorganisms only when the material diffuses well through the pores in the carrier, and the permeability of the waste to be treated is also improved, thereby improving biological treatment efficiency.

PEG-immobilized carriers containing no sludge and PEG-immobilized carriers including nitrified sludge and activated sludge containing various populations of microorganisms were synthesized and tested for the extent of mass diffusion into the carrier. In the case of the immobilized carrier, the pore size is different depending on whether the sludge is included, and thus it is expected to affect the material diffusion. Thus, the degree of material diffusion of the carrier itself, which does not contain the sludge, and the degree of material diffusion of the comprehensive carrier including sludge are divided. Comparative experiments were also made for the variation of the degree of material diffusion according to the type of sludge.

For carrier synthesis including nitrified sludge, MLSS 2700 ~ 3000ppm sludge was used, and for carrier synthesis including activated sludge, MLSS 5500ppm sludge was used. The pH of the two carriers was neutral sludge between 6.5 and 7.0, and the supernatant was removed by centrifugation at 3000 rpm for 10 minutes to remove supernatant, and the carrier was synthesized by encapsulating 10% concentrated sludge 0.5%.

Material diffusion measurement was used as fluorescence reagent (Fluorescein, FW: 332.3) to generate a green color in the maximum absorption wavelength range of 493.5nm and 460nm. Fluorescence solution (fluorescence solution) was prepared by dissolving fluorescein in PBS (phosphate buffered saline) buffer at pH 7.4 to 50 μmol. The PBS buffer was prepared by dissolving a certain amount of NaCl, KCl, Na ₂ HPO ₄ , KH ₂ PO ₄ in tertiary distilled water and adjusting the pH to 7.4 using 1N HCl.

Material diffusion measurement experiments were carried out on three types of carriers: a carrier containing 0.5% of nitrified sludge and activated sludge, and a carrier not containing sludge. In other words, 2 ml of the fluorescein solution was prepared in 11 vials and 5 carriers (diameter 4 × length 4mm) were added, and then 1, 2, 3, 4, 5, 10, 15, 20, and 25, respectively. After soaking for 30 to 60 minutes, the fluorescent material fluorescein was diffused and colored into the carrier.

Three cylindrical carrier samples were taken for each vial, and the degree of diffusion was measured by cutting the central portion of the sample into a 1 mm thick disk using a razor blade. Diffusion observation was performed using a Fluorescence Microscope (OLYMPUS, model name: IX71), and a filter having a detection range of 460 to 490 nm was used in consideration of the maximum absorption wavelength region of fluorescein. As a light source, a mercury burner of 100 W was used, and the degree of diffusion was monitored over time using a CCD detector.

The growth of microorganisms, and by-products and adsorbates in the wastewater can reduce the pore size and pore water, which can adversely affect the diffusion of the material into the carrier. The extent of mass diffusion into the carrier (0.5% Ad.AS carrier) covered with 0.5% activated sludge after use was monitored.

Three samples were used: 0.5% Ad.AS carrier 107 days before and 169 days after the wastewater treatment. Experimental method was carried out in the same manner as the method of mass diffusion test into the carrier using fluorescein.

1 shows the variation of the degree of mass diffusion with time at the carrier center (2,000 μm). From this result, the diffusion coefficient was calculated. As can be seen in Figure 1, D = 3.178 × 10 ^-9 m ² / s for the carrier not containing nitrified sludge of Figure 1a, D = 3.99 × 10 ^-8 m ^{2 for} the 0.5% nitrified sludge carrier of Figure 1b / s, D = 1.122 x 10 ^-8 m ² / s for the 0.5% activated sludge carrier of FIG. 1c. From this, it can be seen that there is a difference of about 10 times in the diffusion coefficient between sludge and sludge. Depending on the type of sludge, it can be seen that the carrier containing soft nitrate sludge is about 3 times faster than the carrier containing harder activated sludge. From this, it can be seen that the degree of material diffusion into the carrier also varies depending on the type of sludge.

Figure 2 shows the change of mass diffusion rate with time at the center of 0.5% Ad.AS carrier before and after wastewater treatment. Based on these results, diffusion coefficients were obtained. As can be seen in Figure 2, the waste water treatment of Figure 2a before and 0.5% of Ad.AS carrier ^{D = 1.122 × 10 - 8 m} 2 / s, even after water treatment of 2b, the elapsed 107 days 0.5% Ad.AS for the carrier ^{D = 4.373 × 10 -9 m 2} / s, were calculated in Figure 2c after waste water treatment in, the case of 0.5% Ad.AS carrier elapsed 169 days ^{D = 3.483 × 10 -9 m 2} / s.

Comparing these results, before the wastewater treatment, in the case of 0.5% Ad.AS carrier (Fig. 2a), it can be seen that the diffusion rate is slowed as the wastewater treatment period is increased, and between 4 months and 6 months (Figs. ), It can be seen that similar values are maintained without significant change in diffusion coefficient. In addition, the difference in diffusion coefficient before and after the wastewater treatment is very small, and it can be seen that this value is larger than the diffusion coefficient D = 3.178 × 10 ⁻⁹ m ² / s of the carrier without sludge. Therefore, even after being used for wastewater treatment for more than six months, it can be seen that the material diffusion rate of the carrier is not substantially affected.

 Surface analysis

This is to confirm the surface structure of the synthesized carrier. In the case of a carrier containing microorganisms, the wet state was observed by WETSEM.

 The surface of the PEG carrier was analyzed using a scanning electron microscope (Topcon, SM-300 SEM). At this time, the carrier was quenched with liquid nitrogen and vacuum-dried for 3 days in a freeze dryer. Each dried sample was fixed to a sample holder and coated with gold (Au) powder to conduct a surface conduction analysis. The pore size and pore size of the surface were confirmed at 2000 times under 15kv condition.

In the case of the carrier made by mixing nitrate sludge, the surface analysis was performed in the state of containing water using the XL30 ESEM (Environmental Scanning Electron Microscope) of Phillips Electron Optics. In order to check the overall surface state of the carrier, the measurement was performed at 200 and 1000 times, which is a low magnification. The carrier was operated for 70 days in an ammonia synthesis wastewater by nitrification test, and then washed with distilled water. Was analyzed. The same carrier undergoing nitrification was lyophilized and confirmed by SEM.

Figure 3 shows a SEM image of the surface of the PEG carrier of Examples 1 to 10. 3A to 3J are surface SEM photographs of the PEG carriers of Examples 1 to 10, respectively. All the magnifications of this photo were fixed at 2,000 times.

As can be seen in Figures 3a to 3j, the carriers of Examples 1 to 10 of the present invention all have a degree of difference, but all have a lot of fine wrinkles it was confirmed that the microorganisms can be well immobilized on the surface of the carrier.

FIG. 4 shows a PEG-1 carrier immediately after synthesis using the sorbitol crosslinking agent of Example 1, a WET SEM photograph of the PEG-1 carrier immediately after immobilization of nitrifying bacteria, and an operation for about 70 days after immobilization. The WET SEM or SEM photograph of the following PEG-1 carrier is shown. Specifically, FIG. 4A shows a PEG-1 carrier (1000x magnification) without nitrifying bacteria, FIG. 4B shows a PEG-1 carrier (1000x magnification) immediately after nitrifying bacteria are immobilized, and FIG. After the operation for about 70 days in the synthetic wastewater of Table 5, and PEG-1 carrier (1000 magnification), and Figure 4d is operated for about 70 days in the synthetic wastewater of Table 5 after 0.5% nitrification is immobilized The surface state of the following PEG-1 support (2000 magnification) is shown.

Referring to FIG. 4, it can be seen that the carrier having immobilized nitrifying bacteria (FIG. 4B) has more pores formed on the surface of the carrier than the carrier having not immobilized nitrifying bacteria (FIG. 4A), and the average pore size is about 5 μm. I could confirm it. After operating these carriers for about 70 days in synthetic wastewater (FIGS. 4C, 4D), it can be seen that the microorganisms multiply and cover the surface of the carrier much more than when initially immobilized.

 Solubility

This is to evaluate the poor solubility of the carrier in the organic solvent. When the actual carrier is applied to a wastewater treatment plant containing hardly decomposable substances, it is necessary to evaluate the resistance to various organic solvents mixed in the wastewater.

In general, solubility tests were conducted for 11 organic solvents that could be included in Hape water. That is, a certain amount of the carrier was put in a tube filled with the same volume of the organic solvent, the tube was placed in a mixer (Thermomixer 5436, Eppendorf, Germany) and stirred for 5 days at 30 ℃ at 1200rpm to measure the solubility.

Table 3 shows the solubility test results for this organic solvent.

Table 3

Carrier of Example 1 Carrier of Example 2 Carrier of Example 3 Carrier of Example 4 Carrier of Example 5 water X X X X X Methanol X X X X X Acetone X X X X 1.74% weight reduction Ethyl acetate X X X X X Dimethyl Sulfoxide (DMSO) X X 0.99% weight reduction 4.76% weight loss 5.90% weight reduction chloroform X X X X X benzene X X X X X toluene X X X X X Dimethylformamide (DMF) X X X X X Tetrahydrofuran (THF) X 2.36% Weight Reduction X 1.28% weight reduction 6.72% Weight Reduction Methylene chloride X X X X X

X: No weight loss.

Referring to Table 3, it can be seen that the PEG carriers of Examples 1 to 5 according to the present invention have excellent stability to organic solvents because dissolution does not occur in most organic solvents. However, it can be seen that the dissolution occurs slightly in the solvent DMSO, THF, the concentration of such solvent in the actual wastewater is not high. Therefore, it can be confirmed that the PEG carrier according to the present invention has excellent stability to organic solvents in actual wastewater treatment.

 Thermal analysis

To evaluate the thermal stability of the synthesized PEG carrier, the melting point (Tm) and glass transition temperature (Tg) of the carrier were measured using a differential scanning calorimetry apparatus (TA Instruments.co, DSC-2010). To do this, put 10 ± 0.5mg of carrier sample into an aluminum pan and compress the sample to prepare the sample, and then operate at a temperature increase rate of 10 ° C / min from -100 to 200 ° C under nitrogen stream (60 ml / min) for each DSC A thermogram was obtained.

In addition, thermogravimetric analysis was conducted to confirm the 5% weight reduction temperature of the PEG carrier. To this end, thermogravimetric analysis was carried out on the PEG carriers of Examples 1 to 10 using a model name TGA-50 manufactured by Shimadzu, Japan, at a temperature rising rate of 10 ° C./min from room temperature to 700 ° C. under nitrogen stream (50 ml / min). It was.

Table 4 summarizes the thermal analysis results for the carriers of Examples 1 to 10.

Table 4

Tg (℃) Tm (℃) ΔH (W / g) Example 1 -46.63 139.34 81.43 Example 2 -44.40 131.93 66.08 Example 3 -43.22 135.65 62.97 Example 4 -48.66 123.34 59.63 Example 5 -48.66 129.38 67.18 Example 6 -49.96 135.84 77.38 Example 7 -48.50 135.87 63.67 Example 8 -46.30 134.05 59.44 Example 9 -53.90 123.51 52.70 Example 10 -50.77 126.23 50.66

Referring to Table 4, it was confirmed that the thermal properties of the carriers of the present invention of Examples 1 to 10 were sufficient to be used as the carrier. In the case of Examples 1 to 5 including the STB as an elastic reinforcing agent, it was confirmed that both Tg and Tm were increased as compared with Examples 6 to 10 without the STB. The enthalpy ΔH required to dissolve the carrier showed similar behavior. From this, it can be seen that all of the carriers according to the present invention of Examples 1 to 10 are sufficient to be used as carriers, but among them, Examples 1 to 5 including STB, which is an elastic reinforcing agent, resulted in thermal properties. This is believed to mean that the rigidity is enhanced by the inclusion of STB in the molecular structure, such as the increase in the compressive strength of PEG carriers by the inclusion of STB, an elastic reinforcing agent.

 Toxicity test

In order to evaluate the self-toxicity of the carrier, the efficiency of nitrification was tested in the ammonia-based synthetic wastewater using the PEG-1 carrier of Example 1 immobilized with low growth bacteria and low viscosity bacteria. This is because the immobilized carrier encompasses the microorganisms in the carrier, and thus, if the carrier is toxic to the microorganism, the biological treatment efficiency cannot be increased.

The test conditions were as follows. The internal reactor temperature was adjusted to 25 ± 1 ° C., while filling 4 L / min of the reactor with 10% of PEG-carrier of Example 1 immobilized at 0.5% and 1%, respectively, for 4 days. Toxicity test experiment was adjusted. The composition of the simulated ammonia synthesis wastewater is shown in Table 5. Over time, the ammonia nitrogen load NH4-N was increased by increasing the flow rate of ammonia synthesis wastewater.

Table 5

Composition of Ammonia Synthetic Wastewater

compound  Concentration (mg / L) NH4HCO3 564.29 as NH4 + NaHCO3 1147.09 as Alkalinity K2HPO4 85.40 as P CaCl2 3.90 AS Ca MgSO4.7H2O 34.00 as Mg MnSO4.H2O 5.00 as Mn FeSO4.7H2O 2.30 as Fe KCl 7.10 as K

Thus, the nitrification efficiency of the PEG-1 carrier was 0.5% and 1% immobilized to the weight of the carrier, respectively.

At the beginning of the experiment, NH4-N was loaded at 0.1 kg / m ³ / day, and ammonia was reduced by gradually increasing the flow rate to evaluate the nitrification capacity as the carrier was adapted. Sex nitrogen was increased by 0.1kg / m ³ / day every 10 to about 20 days and finally increased to 0.9kg / m ³ / day (FIG. 5A).

Figure 5a shows the results of the nitrification treatment efficiency test of PEG-1 carrier immobilized ammonia nitrogen load over time and 0.5% and 1% nitrification bacteria. Referring to FIG. 5A, in a section in which the ammonia nitrogen load is 0.1 kg / m ³ / day between the initial 0 days and about 12 days, the carrier which immobilized 0.5% nitrifier was higher than the carrier which immobilized 1% nitrifier. This adaptation time is long, it can be seen that the initial nitrification treatment efficiency is low. However, as the carrier adapts to the synthetic wastewater over time, it can be seen that after about 70 days of operation, even if the ammonia nitrogen load increases, the carrier shows similar treatment efficiency. Therefore, it can be seen that the fixed amount of the microorganism is about 0.5% relative to the weight of the carrier. As can be seen from Figure 5a, it can be seen that the limit load of the PEG-1 carrier immobilized with nitrifying bacteria is 0.7kg NH4-N / ㎥ / day. Table 6 below plots the results of FIG. 5A for PEG-1 carriers immobilized with 0.5% nitrifier.

Nitrogen Load (kg NH4-N / ㎥ / day) Nitrification Efficiency (%) 0.1 99 0.2 99 0.3 99 0.4 97 0.5 95 0.6 95 0.7 93 0.8 85 0.9 75

Figure 5b records the change in ammonia nitrogen concentration of the influent, the reactor filled with 0.5% nitrifying immobilized PEG-1 carrier, and the reactor filled with 1.0% nitrifying immobilized PEG-1 carrier over time.

Referring to Figure 5b, it can be seen that even after 110 days the treatment efficiency of the nitrifying bacteria immobilized PEG-1 carrier is maintained.

As described above, the hydrophilic immobilized carrier of the present invention can exhibit the following technical effects.

(1) The hydrophilic microorganism immobilization carrier according to the present invention is not toxic to wastewater treatment microorganisms, and microorganisms can be efficiently encapsulated in large quantities, and has a network structure of a reticulated network formed therein. Material diffusion is good. Therefore, it is possible to treat wastewater efficiently by biological method.

(2) The hydrophilic microorganism immobilization carrier according to the present invention has sufficient compressive strength and elasticity, and has durability enough to be used for long-term wastewater treatment. The hydrophilic immobilized carrier according to the present invention is also excellent in thermal properties and poor solubility in organic solvents, and thus can be used for long-term wastewater treatment.

(3) According to the method for producing a carrier according to the present invention, since various microorganisms can be included in the carrier manufacturing process, a carrier can be put in a reaction tank to save time required until the desired microorganism in the carrier is fixed to a predetermined amount or more. There is an advantage.

Claims (11)

Hydrophilic microbial immobilization carrier for wastewater treatment, the carrier, Poly (ethylene glycol) acrylate, poly (ethylene glycol) diacrylate, poly (ethylene glycol) methacrylate, poly (ethylene glycol) dimethacrylate, poly (ethylene glycol) divinyl ether, poly (ethylene glycol) At least one polyethylene glycol component selected from the group consisting of ethyl ether methacrylate, poly (ethylene glycol) methyl ether acrylate, poly (ethylene glycol) methyl ether methacrylate, and poly (ethylene glycol) phenyl ether acrylate Boron-containing polyethylene glycol-based polymer having a three-dimensional network structure crosslinked between the polyethylene glycol-based polymer molecule backbone formed by polymerization and reacting with sodium tetraborate decahydrate to increase the elasticity of the carrier. With oxygen bonds, In addition, the microorganisms to purify the waste water is immobilized and the waste water has a plurality of pores that can enter and exit, the pores are characterized in that extending to each other to form a reticulated network of flow channels (reticulated network of flow channels) Hydrophilic microbial immobilization carrier. The hydrophilic microorganism immobilization carrier according to claim 1, wherein the crosslink is derived from a crosslinking agent comprising 1 to 6 functional groups. The method of claim 2, wherein the crosslinking agent is sorbitol, N, N'- diallyl tardiamide, N, N'- methylenebisacrylamide, diallyl fumarate, 1,5-hexadien-3-ol, or A hydrophilic microorganism immobilization carrier, characterized in that a mixture thereof. delete The hydrophilic microorganism immobilization carrier according to claim 1, wherein the carrier comprises microorganisms for purifying organic matter or nitrogen components in wastewater immobilized in the network flow path of the network structure. The hydrophilic microorganism immobilization carrier according to claim 1, wherein the crosslinking content is formed by reacting 4 to 6 parts by weight of the crosslinking agent based on 100 parts by weight of the polyethylene glycol component. As a method for producing a hydrophilic microorganism immobilization carrier, (a) in a reaction vessel in which an aqueous solvent and a polymerization initiator are present, the polyethylene glycol component and the crosslinking agent are mixed and stirred to polymerize the polyethylene glycol component and form crosslinks between the polymer backbones of the polyethylene glycol component. Forming a polyethylene glycol polymer having a network structure, the reaction vessel including sodium tetraborate decahydrate to increase elasticity of the obtained carrier; (b) neutralizing the polyethylene glycol polymer solution to adjust the pH of the solution in the range of 6 to 8 and converting the polymer solution into a gel state; And (c) extruding the gelled polyethylene glycol polymer solution to obtain a carrier having a plurality of pores extending from each other to form a reticulated network of flow channels. delete The method according to claim 7, further comprising the step of adjusting the pH to a range of 6 to 8 in the step (b), and then enclosing the microorganisms in the pores of the carrier by injecting and aging the sludge containing the microorganisms into the reaction vessel. Carrier production method characterized in that. 8. The method of claim 7, wherein the reaction vessel of step (a) further comprises an accelerator for allowing radical polymerization to proceed at room temperature. 8. The method of claim 7, wherein the polyethylene glycol component and the crosslinking agent are mixed with 4 to 6 parts by weight of the crosslinking agent based on 100 parts by weight of the polyethylene glycol component.

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