Microbial carrier and wastewater treatment device

Abstract

The present disclosure provides a microbial carrier and a wastewater treatment device. According to embodiments of the present disclosure, the microbial carrier includes a bacteriophilic material and a plurality of cells, wherein the plurality of cells are disposed in the bacteriophilic material. The bacteriophilic material is a reaction product of a composition, wherein the composition includes a hydrophobic polyvinyl alcohol and a crosslinking agent, wherein a surface energy of the hydrophobic polyvinyl alcohol is 30 mJ / m 2 to 58 mJ / m 2 .

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a microbial carrier and a wastewater treatment device. BACKGROUND

[0002] Wastewater with high ammonia-nitrogen concentration is usually found in high-tech industries, such as semiconductor manufacturing or light-emitting diode (LED) manufacturing. In the process, ammonia gas or ammonia water is mainly used, and the resulting high-concentration ammonia-nitrogen wastewater is discharged into a wastewater treatment plant for treatment.

[0003] The conventional ammonia-nitrogen biological treatment method is the nitrification-denitrification method, which must go through a series of biological reactions, including oxidation of ammonia-nitrogen to nitrite-nitrogen by ammonia oxidation bacteria (AOB). Subsequently, nitrite-nitrogen is oxidized to nitrate-nitrogen by nitrite oxidation bacteria (NOB). Finally, denitrifying bacteria take over to reduce nitrite-nitrogen to nitrogen gas for treatment. Since the conventional ammonia-nitrogen biological treatment method requires a large amount of aeration and additional organic matter as a carbon source for denitrification reaction, the overall operation is energy-consuming and the operating cost is high.

[0004] A more novel ammonia-nitrogen treatment method is the anammox process, in which the microorganism uses naturally occurring carbon dioxide (CO2) as a carbon source under anaerobic conditions, directly uses ammonia-nitrogen as an electron donor and nitrite-nitrogen as an electron acceptor to perform a three-electron transfer reaction to generate nitrogen gas. This process does not require additional costs and energy as in the conventional nitrogen removal process, does not need to provide a large amount of oxygen to convert ammonia-nitrogen to nitrate-nitrogen, and does not need to provide an organic carbon source for denitrification reaction.

[0005] Due to the biochemical reaction of anammox microorganisms, ammonia-nitrogen and nitrite-nitrogen are required to participate in the reaction (nitrite-nitrogen is the electron acceptor). Therefore, there is no nitrite-nitrogen in general ammonia-nitrogen wastewater, and another strain of microorganism (such as ammonia oxidation bacteria (AOB)) is needed to oxidize part of the ammonia-nitrogen to nitrite-nitrogen, and then the anammox microorganism performs anammox reaction to form nitrogen gas.

[0006] Since ammonia nitrogen treatment is generally carried out in a high water flow shear environment, a carrier with sufficient mechanical strength is required to carry microorganisms. The materials of commercially available hard microbial carriers are mainly polyurethane (PU) or high-density polyethylene (HDPE). However, since these materials (such as polyurethane or high-density polyethylene) have a high surface energy, the adhesion of anaerobic ammonia oxidation bacteria and ammonia oxidation bacteria is low, resulting in a decrease in the total nitrogen degradation rate and total nitrogen removal rate of wastewater treatment. SUMMARY

[0007] The present disclosure provides a microbial carrier. According to embodiments of the present disclosure, the microbial carrier includes a bacteriophilic material and a plurality of cells, wherein the plurality of cells are disposed in the bacteriophilic material. The bacteriophilic material is a reaction product of a composition, wherein the composition includes a hydrophobic polyvinyl alcohol and a crosslinking agent, wherein the surface energy of the hydrophobic polyvinyl alcohol is 30 mJ / m 2 to 58 mJ / m 2 .

[0008] The present disclosure also provides a wastewater treatment device for removing a pollutant in a wastewater. The device includes the microbial carrier described in the present disclosure; and a microorganism disposed on the microbial carrier. BRIEF DESCRIPTION OF DRAWINGS

[0009] Figure 1 is a graph of the relationship between the influent concentration and the effluent concentration and the operation time of the microbial carrier (1) of Example 1 of the present disclosure in the nitrogen compound purification treatment test;

[0010] Figure 2 is a graph of the relationship between the total nitrogen volumetric loading and the removal rate and the operation time of the microbial carrier (1) of Example 1 of the present disclosure in the nitrogen compound purification treatment test;

[0011] Figure 3 is a graph of the relationship between the influent concentration, the effluent concentration, and the removal rate and the operation time of the microbial carrier (1) of Example 1 of the present disclosure in the total nitrogen removal analysis; and

[0012] Figure 4 is a graph of the relationship between the influent concentration, the effluent concentration, and the removal rate and the operation time of the commercially available HDPE microbial carrier in the total nitrogen removal analysis. DETAILED DESCRIPTION

[0013] The following provides a detailed description of the microbial carrier and wastewater treatment apparatus disclosed herein. It should be understood that the following description provides many different embodiments or examples for implementing various aspects of this disclosure. The specific elements and arrangements described below are merely for illustrative purposes and are not intended to limit the scope of this disclosure. Furthermore, repeated reference numerals or designations may be used in different embodiments. These repetitions are solely for the purpose of clearly and simply describing this disclosure and do not represent any connection between the different embodiments and / or structures discussed. In this disclosure, the term "about" means an amount that can be increased or decreased by a size that is generally and reasonably understood by those skilled in the art.

[0014] It is important to understand that the use of ordinal numbers such as "first," "second," "third," etc., in the specification and claims to modify the elements of the claims does not imply or represent any prior ordinal number of the claimed element, nor does it represent the order of one claimed element with another, or the order of manufacturing methods. The use of these ordinal numbers is only to enable a claim element with a certain name to be clearly distinguished from another claim element with the same name.

[0015] This disclosure provides a microbial carrier and a wastewater treatment device. The microbial carrier comprises a probiotic material and multiple pores, wherein the probiotic material is prepared from a hydrophobic polyvinyl alcohol and a crosslinking agent. Due to the low surface energy of the hydrophobic polyvinyl alcohol, the microbial carrier disclosed herein is suitable for the rapid attachment of microorganisms (e.g., anaerobic ammonia oxidizing bacteria and ammonia oxidizing bacteria) to the biocarrier. Furthermore, because the microbial carrier disclosed herein possesses advantages such as high hardness, low wear, high roughness, and high specific surface area, it is not only suitable for operation in high-flow-shear environments but also increases the amount of microorganisms attached to the carrier (compared to traditional high-density polyethylene). Moreover, when the microbial carrier disclosed herein is used for wastewater treatment, it allows multiple microorganisms (e.g., anaerobic ammonia oxidizing bacteria and ammonia oxidizing bacteria) to rapidly attach and exist in large quantities on the same microbial carrier, increasing the total nitrogen degradation rate and total nitrogen removal rate during wastewater treatment. In this way, nitrogen-containing compounds (such as ammonia nitrogen and nitrite nitrogen) in wastewater can be more effectively converted into nitrogen gas.

[0016] According to embodiments of this disclosure, a microbial carrier is provided, which may comprise a bacteriophilic material and a plurality of pores. According to embodiments of this disclosure, the plurality of pores are disposed within the bacteriophilic material, wherein the bacteriophilic material is a reaction product of a composition. According to embodiments of this disclosure, the composition may comprise a hydrophobic polyvinyl alcohol and a crosslinking agent. According to embodiments of this disclosure, the weight ratio of the hydrophobic polyvinyl alcohol and the crosslinking agent may be from about 1:9 to 4:6, for example, about 2:8 or 3:7. According to embodiments of this disclosure, the composition may consist of the hydrophobic polyvinyl alcohol and the crosslinking agent.

[0017] According to embodiments of the present disclosure, the hydrophobic polyvinyl alcohol can be obtained by reacting an unmodified polyvinyl alcohol (or a partially crosslinked polyvinyl alcohol resin by boric acid) with a modifying agent. According to embodiments of the present disclosure, the modifying agent can be a siloxane having C 6-18 alkyl groups, a siloxane having C 6-22 alkenyl groups, a succinic anhydride having C 6-18 alkyl groups, a succinic anhydride having C 6-22 alkenyl groups, an isocyanate having C 6-18 alkyl groups, an isocyanate having C 6-22 alkenyl groups, or a lactone having 3-7 carbons.

[0018] According to embodiments of the present disclosure, the modifying agent can be Si(R 2 )4、

[0019] O=C=N-R 4 , or R 2 is independently C 1-6 alkoxy, C 6-18 alkyl, or C 6-22 alkenyl, and at least one R 2 is C 6-18 alkyl, or C 6-22 alkenyl, and at least one R 2 is C 1-6 alkoxy; R 3 and R 4 are C 6-18 alkyl, or C 6-22alkenyl; and j is 3 to 7. For example, the modifying agent can be hexyltriethoxysilane, octyltriethoxysilane, decyltriethoxysilane, dodecyltriethoxysilane, hexadecyltrimethoxysilane, octadecyltriethoxysilane, decenyltrimethoxysilane, dodecenyltriethoxysilane, decyl succinicanhydride, dodecyl succinic anhydride, octadecyl succinic anhydride, docosyl succinicanhydride, decenyl succinic anhydride, dodecenyl succinic anhydride, octadecenyl succinicanhydride, docosenyl succinic anhydride, hexylisocyanate, octyl isocyanate, dodecylisocyanate, octadecyl isocyanate, dodecenylisocyanate, octadecenyl isocyanate, γ-butyrolactone, δ-Valerolactone, ε-caprolactone, or a combination thereof.

[0020] According to embodiments of the present disclosure, the crosslinking agent can be C 1-9aldehyde, acetaldehyde, glyoxal, methylglyoxal, propionaldehyde, acrolein, malondialdehyde, butyraldehyde, valeraldehyde, glutaraldehyde, hexanal, heptaldehyde, benzaldehyde, anisaldehyde, cuminaldehyde, or a combination thereof.

[0021] According to embodiments of the present disclosure, the crosslinking agent of the present disclosure can be only an aliphatic polyisocyanate to avoid using aldehyde compounds as the crosslinking agent. According to embodiments of the present disclosure, the crosslinking agent of the present disclosure can be 2,4-toluene diisocyanate, 2,5-toluene diisocyanate, 2,6-toluene diisocyanate, hexamethylene diisocyanate, pentamethylene diisocyanate, isophorone diisocyanate, 4,4'-Methylene dicyclohexyl diisocyanate, 4,4'-methylenediphenyl diisocyanate, or a combination thereof.

[0022] According to embodiments of this disclosure, the composition used to prepare the biocompatible material disclosed herein may further include a catalyst to accelerate the crosslinking reaction of the composition. According to embodiments of this disclosure, the amount of the catalyst used may be from 0.01 wt% to 5 wt%, along with the hydrophobic polyvinyl alcohol and the crosslinking agent. According to the embodiments disclosed herein, the catalyst may be bismuth nitrate, lead 2-ethylhexoate, lead benzoate, ferric chloride, antimony trichloride, antimony glycolate, stannous salts of carboxylic acids, zinc salts of carboxylic acids, dialkyl tin salts of carboxylicacids, glycine salts, tertiary amine trimerization catalysts, quaternary ammonium carboxylates, alkalimetal carboxylic acid salts, potassium acetate, potassium octoate, or potassium 2-ethylhexanoate. 2-ethylhexanoate), N-(2-hydroxy-5-nonylphenol)methyl-N-methylglycinate, (II)tin(II)2-ethylhexanoate, dibutyltin dilaurate, or combinations thereof. According to embodiments disclosed herein, the above composition may consist of hydrophobic polyvinyl alcohol, a crosslinking agent, and a catalyst.

[0023] According to the embodiments disclosed herein, the surface energy of the hydrophobic polyvinyl alcohol can be approximately 30 mJ / m². 2 Up to 58mJ / m 2 For example, 33mJ / m 2 Up to 58mJ / m 2 35mJ / m 2 Up to 58mJ / m 2 37mJ / m 2 Up to 58mJ / m2 , or 33 mJ / m 2 to 56 mJ / m 2 The surface energy of the hydrophobic polyvinyl alcohol can be adjusted as needed (by adjusting the number of hydrophobic functional groups or the bond length of the hydrophobic functional groups of the polyvinyl alcohol) to reduce the difference in surface energy between the microbial carrier and the microorganism to be carried and increase the adhesion of the microorganism to the microbial carrier. According to embodiments of the present disclosure, since the bacteriophilic material is prepared from the hydrophobic polyvinyl alcohol, the surface energy of the bacteriophilic material can also be 30 mJ / m 2 to 58 mJ / m 2 Here, the surface energy of the present disclosure is evaluated by measuring the contact angle using pure water, formamide, respectively, and calculating the solid surface energy using Wetting Tension.

[0024] According to embodiments of the present disclosure, the Shore D hardness of the microbial carrier of the present disclosure can be about 50 to 80, such as about 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, or 79. According to embodiments of the present disclosure, the abrasion of the microbial carrier is 100 mg / 1000 cycles to 200 mg / 1000 cycles. When the hardness or abrasion of the microbial carrier is too low, it is less suitable for operation in a high water flow shear environment. Here, the hardness (Shore Hardness A) is determined according to the method specified in ASTM D-2240. The measurement of abrasion is carried out according to ASTM D4060 (1000 cycles, CS-17 mg grinding wheel, weight 1000 grams) to determine the Taber abrasion resistance.

[0025] According to embodiments of the present disclosure, the microbial carrier of the present disclosure can have an average pore diameter of about 100 μm to 600 μm, such as about 150 μm to 600 μm, or 200 μm to 500 μm. In addition, according to embodiments of the present disclosure, the porosity of the microbial carrier of the present disclosure can be 25 to 60%, such as 25% to 30%, or 30% to 40%, or 40% to 50%, or 50% to 56%. In addition, according to embodiments of the present disclosure, the specific surface area of the microbial carrier of the present disclosure can be about 4000 m 2 / m 3 to 7000 m 2 / m 3 , such as 4500 m 2 / m3 to 7000 m 2 / m 3 , 4800 m 2 / m 3 to 7000 m 2 / m 3 , or 5000 m 2 / m 3 to 7000 m 2 / m 3 When the average porosity or specific surface area of the microbial carrier of the present disclosure is small, the microorganisms are less likely to quickly adhere to the microbial carrier of the present disclosure. When the average pore size of the microbial carrier of the present disclosure is low, the rate of water flow through the pores increases, so that the residence time of the microorganisms around the pores is short, resulting in a decrease in the amount of microorganism adhesion of the microbial carrier of the present disclosure. Therefore, by controlling the average pore size and porosity in an appropriate range (for example, the average pore size is 200 μm to 400 μm, and the porosity is 25% to 60%), the microbial carrier of the present disclosure can have a larger amount of microorganism adhesion. Here, the average pore size and specific surface area are measured by a multifunctional 3D XCT (BRUKER SKYSCAN 2211).

[0026] According to embodiments of the present disclosure, when the microbial carrier of the present disclosure is used to carry microorganisms, the total amount of microorganism adhesion can be 8 mg vss / g carrier to 50 mg VSS / g carrier , for example, 8 mg vss / g carrier to 45 mg VSS / g carrier , 10 mg vss / g carrier to 50 mg VSS / g carrier , 15 mg vss / g carrier to 50 mg VSS / g carrier , or 20 mg vss / g carrier to 50 mg VSS / g carrier . Here, the evaluation method of the total amount of microorganism adhesion is to measure the amount of microorganism adhesion by the NIEA R212.02 C method for measuring the volatile solid content of sludge.

[0027] According to embodiments disclosed herein, the hydrophobic polyvinyl alcohol may comprise a first repeating unit and a second repeating unit, wherein the first repeating unit has the structure shown in formula (I) and the second repeating unit has the structure shown in formula (II):

[0028]

[0029] , where R 1 It is -Si(R) 2 3. R 2 It is independent as C 1-6 Alkoxy, C 6-18 Alkyl, or C 6-22 alkenyl, and R 2 At least one of them is C 6-18 Alkyl, or C 6-22 alkenyl; R 3 and R 4 It is independent as C 6-18 Alkyl, or C 6-22 alkenyl; R 5 and R 6 The components are independently hydrogen, fluorine, methyl, or ethyl; j is 3 to 7; and k is 1 to 30. According to the embodiments disclosed herein, the hydrophobic polyvinyl alcohol has n first repeating units and m second repeating units, wherein n:m can be about 1:100 to 2:1, for example about 1:50, 1:30, 1:20, 1:10, 1:5, 1:2, or 1:1.

[0030] According to the embodiments disclosed herein, C 1-6 Alkyl groups can be linear or branched alkoxy groups. For example, C 1-6 The alkoxy group is methoxy, ethoxy, propoxy, butoxy, pentoxy, hexoxy, or an isomer thereof. According to the embodiments disclosed herein, C 6-18 Alkyl groups can be straight-chain or branched-chain. For example, C 6-18The alkyl group can be hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl, or an isomer thereof. According to embodiments of the present disclosure, j can be 3, 4, 5, 6, or 7; and, k can be 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, or 30. 6-22 The alkenyl group can be a linear or branched chain alkenyl group. For example, the alkenyl group can be hexenyl, heptenyl, octenyl, nonenyl, decenyl, undecenyl, dodecenyl, tridecenyl, tetradecenyl, pentadecenyl, hexadecenyl, heptadecenyl, octadecenyl, or an isomer thereof. According to embodiments of the present disclosure, j can be 3, 4, 5, 6, or 7; and, k can be 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, or 30. 6-22 The alkenyl group can be a linear or branched chain alkenyl group. For example, the alkenyl group can be hexenyl, heptenyl, octenyl, nonenyl, decenyl, undecenyl, dodecenyl, tridecenyl, tetradecenyl, pentadecenyl, hexadecenyl, heptadecenyl, octadecenyl, or an isomer thereof. According to embodiments of the present disclosure, j can be 3, 4, 5, 6, or 7; and, k can be 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, or 30.

[0031] According to embodiments of the present disclosure, the first repeating unit can be wherein R 5 and R 6 are independently hydrogen, fluorine, methyl, or ethyl; j is 3 to 7; and, k is 1 to 30.

[0032] According to embodiments of the present disclosure, the hydrophobic polyvinyl alcohol can have a weight average molecular weight of 2,000 g / mol to 2,000,000 g / mol, such as about 2,000 g / mol to 1,500,000 g / mol, 10,000 g / mol to 2,000,000 g / mol, 5,000 g / mol to 2,000,000 g / mol, 5,000 g / mol to 1,500,000 g / mol, 5,000 g / mol to 1,000,000 g / mol, 8,000 g / mol to 1,000,000 g / mol, or 8,000 g / mol to 500,000 g / mol. The weight average molecular weight (Mw) of the hydrophobic polyvinyl alcohol of the present disclosure can be measured by gel permeation chromatography (GPC) with polystyrene as a standard.

[0033] According to embodiments of the present disclosure, the present disclosure also provides a wastewater treatment device for removing a pollutant in a wastewater. The wastewater treatment device can include the microbial carrier described above, and a microorganism disposed on the microbial carrier. According to embodiments of the present disclosure, the pollutant can be a nitrogenous compound, organic matter, or a combination thereof. According to embodiments of the present disclosure, the microorganism can be ammonia oxidation bacteria (AOB), anammox bacteria, heterotrophic bacteria, methanogenic bacteria, or a combination thereof. According to embodiments of the present disclosure, the wastewater treatment device can have a pollutant removal rate of 50% to 96% within 10 days of treating the wastewater with the wastewater treatment device. Here, the pollutant removal rate is calculated by the influent concentration and effluent concentration of the pollutant.

[0034] In order to make the above and other objects, features, and advantages of the present disclosure more comprehensible, specific embodiments and comparative examples are described in detail below:

[0035] Preparation of hydrophobic polyvinyl alcohol

[0036] Preparation Example 1

[0037] Under a nitrogen atmosphere, 1 part by weight of polyvinyl alcohol (trade name: BP-05, manufactured and sold by Teikoku Chemicals) and dimethyl sulfoxide (DMSO) (20 parts by weight) were added to a reaction flask. Subsequently, the reaction flask was heated to 80°C, and the polyvinyl alcohol was completely dissolved in the dimethyl sulfoxide to obtain a solution. After 30 minutes of reaction, ε-caprolactone (10 parts by weight) was added to the reaction flask, and the reaction flask was heated to 100°C. After 24 hours of reaction, the reaction flask was cooled to 0°C, and the resulting product was subjected to a reprecipitation treatment. The reprecipitation treatment included dissolving the resulting product in acetone (100 parts by weight), pouring the resulting solution into methanol (1000 parts by weight) to perform reprecipitation, and collecting the solid. After repeating the reprecipitation treatment twice, the resulting solid was heated to 80°C under vacuum and dried for 5 hours to obtain a hydrophobic polyvinyl alcohol (1).

[0038] The hydrophobic polyvinyl alcohol (1) was analyzed by nuclear magnetic resonance spectroscopy, and the resulting spectral information was as follows. 1 H NMR (400 MHz, ppm, CDCl3): 5.12-4.92 (-CH2- connected to polycaprolactone (PCL), m), 4.12-4.02 [- (CO) -CH2CH2CH2CH2CH2O, 5th alkylene group (counted from the carbonyl group of the PCL repeating unit)], 3.70-3.62 [- (CO) -CH2CH2CH2CH2CH2OH, terminal -OH group of the PCL repeating unit], 2.35-2.24 [- (CO) -CH2CH2CH2CH2CH2O, 1st alkylene group (counted from the carbonyl group of the PCL repeating unit)], 1.72-1.56 [- (CO) -CH2CH2CH2CH2CH2OH, 2nd and 4th alkylene groups (counted from the carbonyl group of the PCL repeating unit)], 1.42-1.33 ppm [- (CO) -CH2CH2CH2CH2CH2O, 3rd alkylene group (counted from the carbonyl group of the PCL repeating unit)].

[0039] Subsequently, the hydrophobic polyvinyl alcohol (1) was measured by Fourier transform infrared spectroscopy (FTIR). From the results, it was found that there was a large absorption intensity at 1720 cm -1 indicating the formation of an ester group (having a C=O bond); in addition, there was a large absorption intensity at 1639 cm -1 which is the asymmetric stretching vibration of the C=O bond of polycaprolactone, indicating that the polycaprolactone chain segment was indeed grafted to the polyvinyl alcohol.

[0040] Preparation Example 2

[0041] Preparation Example 2 was performed in the same manner as described in Preparation Example 1, except that the amount of ε-caprolactone was increased from 10 parts by weight to 20 parts by weight, to obtain the hydrophobic polyvinyl alcohol (2).

[0042] Next, the melting temperature (Tm) and the surface energy of the polyvinyl alcohol (commercially available under the product number BP-05, manufactured and sold by Teikoku Chemicals) and the hydrophobic polyvinyl alcohols (1) and (2) were measured, and the results are shown in Table 1. The melting temperature was measured using a differential scanning calorimetry (DSC). The surface energy was evaluated by measuring the contact angle using pure water and formamide, respectively, and calculating the solid surface energy using WettingTension.

[0043] Table 1

[0044] Melting point (°C) Surface energy (mJ / m 2 )] Polyvinyl alcohol 200 58.07 Hydrophobic polyvinyl alcohol (1) 53 54.2 Hydrophobic polyvinyl alcohol (2) 53 39.0

[0045] As shown in Table 1, the surface energy of the hydrophobic polyvinyl alcohol of the present disclosure is lower than that of the unmodified polyvinyl alcohol, and the water resistance of the material can be improved. In addition, when the surface energy of the carrier is closer to the surface energy of the microorganism to be carried, the adhesion of the carrier to the microorganism is higher. For example, the surface energy of ammonia oxidation bacteria (AOB) is about 44.49 mJ / m2, and the surface energy of the hydrophobic polyvinyl alcohol (2) is about 44.49 mJ / m2, which is close to the surface energy of the ammonia oxidation bacteria. Therefore, the adhesion of the ammonia oxidation bacteria to the carrier is higher. 2 Compared with the unmodified polyvinyl alcohol, the absolute value of the difference between the surface energy of the hydrophobic polyvinyl alcohol of the present disclosure and the ammonia oxidation bacteria is smaller, resulting in an increase in the adhesion of the microorganism to the carrier. In this way, through the lower surface energy, the surface of the hydrophobic polyvinyl alcohol of the present disclosure is suitable for the adhesion of the ammonia oxidation bacteria.

[0046] Preparation of the microbial carrier

[0047] Example 1

[0048] The hydrophobic polyvinyl alcohol (2) (5 parts by weight), polyethylene glycol (commercially available under the product number PEG Polyethylene Glycol #400, manufactured and sold by Teikoku Chemicals) (1.8 parts by weight), and an aliphatic polyisocyanate (commercially available under the product number Coronate HXLV, manufactured and sold by TRIISO) (as a cross-linking agent) (20 parts by weight) were uniformly mixed to obtain a mixture. Next, the obtained mixture was heated to 60°C. After stirring for 5 minutes, stannous 2-ethyl-hexanoate (Sn(oct)2) (as a catalyst) (0.02 parts by weight) was mixed with the obtained mixture at room temperature. After stirring for 3 minutes, the obtained mixture was heated to 100°C. After 2 hours, the obtained mixture was cooled to room temperature to obtain the microbial carrier (1).

[0049] Example 2

[0050] Example 2 was performed in the same manner as described in Example 1, except that the amount of crosslinking agent was reduced (i.e., the ratio of hydrophobic polyvinyl alcohol to crosslinking agent was greater than about 0.33), to obtain microbial carrier (2).

[0051] Example 3

[0052] Example 3 was performed in the same manner as described in Example 1, except that the amount of crosslinking agent was increased (i.e., the ratio of hydrophobic polyvinyl alcohol to crosslinking agent was less than about 0.2), to obtain microbial carrier (3).

[0053] Evaluation of properties of microbial carriers

[0054] The surface roughness of hydrophobic polyvinyl alcohol (2) and microbial carrier (1) described in Example 1 was measured, and the results are shown in Table 2. The surface roughness was measured using a surface roughness meter (Surfcorder SE1700) according to the method specified in ASTM D7127-13.

[0055] Table 2

[0056] Surface roughness Hydrophobic polyvinyl alcohol (2) ~ 80.5 ± 7 μm Microbial carrier ~ 592.6 ± 142 μm

[0057] As can be seen from Table 2, the surface roughness of microbial carrier (1) described in Example 1 (obtained by chemical foaming of crosslinking agent on hydrophobic polyvinyl alcohol (2)) was greatly improved compared to hydrophobic polyvinyl alcohol (2). As such, when the microorganisms initially attach to the carrier, the carrier with high surface roughness can resist the shear force of water flow, allowing the microorganisms to more easily attach to the carrier.

[0058] The average pore size, specific surface area, hardness, and abrasion of microbial carriers (1)-(3) were measured and compared with commercially available polyvinyl alcohol sponge (product number PN1129, manufactured and sold by 3M) and commercially available high-density polyethylene carrier (product number MutagBioChip 30 TM , manufactured and sold by MutagBioChip), and the results are shown in Table 3. The average pore size and specific surface area were measured using a multifunctional 3D XCT (BRUKER SKYSCAN 2211). The hardness (Shore Hardness A) was measured according to the method specified in ASTM D-2240. The abrasion was measured according to ASTM D4060 (1000 cycles, CS-17 mg grinding wheel, weight 1000 grams) to determine the Taber abrasion resistance.

[0059] Table 3

[0060]

[0061]

[0062] As shown in Table 3, the microbial carrier (1) of Example 1 has a significantly improved hardness compared to polyvinyl alcohol sponge and high-density polyethylene carrier. In addition, as shown in Table 3, the average pore size, specific surface area, and porosity of the microbial carrier of the present disclosure can be adjusted by the amount of crosslinking agent used.

[0063] Nitrogen compound purification treatment test

[0064] The microbial carrier (1) of Example 1 was subjected to a nitrogen compound purification treatment test for nitrogen-containing substances in wastewater having a specific concentration range of nitrogen-containing compounds, in order to evaluate the total nitrogen removal rate of the microbial carrier (1) of Example 1. The results are shown in Figure 1 and Figure 2 The conditions for the above-mentioned nitrogen compound purification treatment test were as follows: the volume of the reaction tank was 3 L, the volume of the biological carrier was 1 L; the ammonia nitrogen concentration in the influent wastewater was between 130 mg / L and 160 mg / L; the hydraulic retention time of the reaction tank was 0.336 days; the pH of the reaction tank was controlled between 7.5 and 7.9; the selected microorganism was ammonia oxidation bacteria (AOB); the dissolved oxygen concentration of the reaction tank was maintained at 0.2 mg / L to 0.6 mg / L; and the ammonia nitrogen concentration was determined by ion chromatography.

[0065] As shown in Figure 1 and Figure 2 , the microbial carrier of the present disclosure can effectively remove nitrogen-containing pollutants in wastewater when applied to nitrogen-containing pollutant purification treatment (the ammonia nitrogen removal rate can reach 77%, and the ammonia nitrogen volumetric loading can be between 0.37 and 0.47).

[0066] Bacterial amount analysis

[0067] The microbial carriers (1)-(3) and a commercially available microbial carrier (Mutag BioChip, material: HDPE) (specific surface area > 5,500 m 2 / m 3) and anaerobic ammonia oxidizing bacteria, surface energy difference, and ammonia oxidizing bacteria adhesion, as shown in Table 4. Here, the total microorganism adhesion amount is evaluated by the sludge volatile solid detection method (NIEA R212.02 C) announced by the Environmental Protection Administration; the ammonia oxidizing bacteria adhesion amount and the anaerobic ammonia oxidizing bacteria adhesion amount are quantitatively analyzed by real-time PCR; the surface energy difference is the absolute value of the surface energy difference between the microorganism carrier and the ammonia oxidizing bacteria; and the ammonia oxidizing bacteria adhesion is detected by an atomic force microscope (AFM) as a detection unit, and the cantilever (micron level) bending deflection amount is used to determine the ammonia oxidizing bacteria adhesion on the carrier.

[0068] Table 4

[0069]

[0070] As shown in Table 4, compared with the commercially available HDPE microorganism carrier, the microorganism carrier prepared from the hydrophobic polyethylene has a surface energy close to that of the microorganism, thereby increasing the adhesion of the microorganism on the carrier and having the function of allowing a large amount of ammonia oxidizing bacteria and anaerobic ammonia oxidizing bacteria to adhere.

[0071] Total nitrogen degradation rate analysis

[0072] The microorganism carrier (1) described in Example 1 and the commercially available microorganism carrier (Mutag BioChip, material: HDPE) (specific surface area > 5,500 m 2 / m 3 ) were subjected to total nitrogen degradation rate analysis, and the results are shown in Table 5. The total nitrogen degradation rate was evaluated by adding a simulated wastewater having a total nitrogen concentration of about 60 mg / L to a wastewater volume of 250 mL, adding 8.6 g of the biological carrier, stirring with a magnet, and sampling at different times within 72 hours, and then analyzing the ammonia nitrogen, nitrite nitrogen, and nitrate nitrogen concentrations at different times by ion chromatography, and adding the total nitrogen concentration at different times. Here, the total nitrogen concentration refers to the total target nitrogen, i.e., the sum of the ammonia nitrogen, nitrite nitrogen, and nitrate nitrogen concentrations.

[0073] Table 5

[0074]

[0075] As shown in Table 5, compared with the commercially available HDPE microorganism carrier, the total nitrogen degradation rate of the microorganism carrier of the present disclosure can be increased by more than 10 times.

[0076] Total nitrogen removal rate analysis

[0077] The microbial carrier (1) described in Example 1 and a commercially available microbial carrier (MutagBioChip, made of HDPE) with a specific surface area > 5,500 m² were used. 2 / m 3 The total nitrogen removal rate was analyzed, and the results are as follows: Figure 3 and Figure 4 As shown. The reactor volume is 3L, and the biological carrier filling volume is 1L; the total nitrogen concentration in the influent wastewater ranges from 50mg / L to 100mg / L; the hydraulic retention time of the reactor is 0.336 days; the pH value of the reactor is controlled between 7.5 and 7.9; the selected microorganisms are ammonia-oxidizing bacteria (AOB) and anammox bacteria; the dissolved oxygen concentration in the reactor is maintained between 0.2mg / L and 0.6mg / L; and the total nitrogen concentration is determined by ion chromatography.

[0078] Depend on Figure 3 It can be seen that the average total nitrogen removal rate of the microbial carrier (1) disclosed in Example 1 of this disclosure can reach 67.58% (measurement period of 45 days), while the total nitrogen removal rate of commercially available HDPE microbial carriers is only 50.01% (measurement period of 45 days). Furthermore, the average total nitrogen concentration of the effluent from the microbial carrier described in Example 1 is 26.55 mg / L, which meets the regulatory standard (less than 35 mg / L). However, due to… Figure 4 It is known that the average total nitrogen concentration of the commercially available HDPE microbial carrier effluent is 40.07 mg / L, which does not meet the regulatory standards.

[0079] In summary, the microbial carrier disclosed herein enables microorganisms (such as anaerobic ammonia oxidizing bacteria and ammonia oxidizing bacteria) to rapidly attach to the carrier, thereby increasing the amount of microorganisms attached. Consequently, when the microbial carrier disclosed herein is used for wastewater treatment, it can improve the total nitrogen degradation rate and total nitrogen removal rate during wastewater treatment.

[0080] Although this disclosure has been presented above with reference to several embodiments, it is not intended to limit this disclosure. Anyone skilled in the art can make any modifications and alterations without departing from the spirit and scope of this disclosure. Therefore, the scope of protection of this disclosure shall be determined by the scope defined in the appended claims.

Claims

1. A microbial carrier, characterized in that, The product comprises a bacteriophilic material and multiple pores, wherein the multiple pores are disposed within the bacteriophilic material, wherein the bacteriophilic material is a reaction product of a composition, wherein the composition comprises a hydrophobic polyvinyl alcohol and a crosslinking agent, wherein the surface energy of the hydrophobic polyvinyl alcohol is 30 mJ / m². 2 Up to 58mJ / m 2 ; The hydrophobic polyvinyl alcohol comprises a first repeating unit and a second repeating unit, wherein the first repeating unit has the structure shown in formula (I) and the second repeating unit has the structure shown in formula (II). , Where R 1 It is -Si(R) 2 3. R 2 It is independent as C 1-6 Alkoxy, C 6-18 Alkyl, or C 6-22 alkenyl, and R 2 At least one of them is C 6-18 Alkyl, or C 6-22 alkenyl; R 3 and R 4 It is independent as C 6-18 Alkyl, or C 6-22 alkenyl; R 5 and R 6 It is independently hydrogen, fluorine, methyl, or ethyl; j is 3 to 7; and k is 1 to 30; The hydrophobic polyvinyl alcohol has n first repeating units and m second repeating units, where n:m is 1:100 to 2:

1.

2. The microbial carrier as described in claim 1, characterized in that, The Shore D hardness of this microbial carrier is 50 to 80.

3. The microbial carrier as described in claim 1, characterized in that, The average pore size of this microbial vector is 100 μm to 600 μm.

4. The microbial carrier as described in claim 1, characterized in that, The porosity of this microbial carrier is 25% to 60%.

5. The microbial carrier as described in claim 1, characterized in that, The specific surface area of ​​this microbial carrier is 4000 m². 2 / m 3 up to 7000m 2 / m 3 .

6. The microbial carrier as described in claim 1, characterized in that, The wear rate of this microbial carrier is from 100 mg / 1000 cycles to 200 mg / 1000 cycles.

7. The microbial carrier as described in claim 1, characterized in that, The amount of microorganisms attached to the microbial carrier was 8 mg. vss / g carrier Up to 50mg VSS / g carrier .

8. The microbial carrier as described in claim 1, characterized in that, The weight ratio of the hydrophobic polyvinyl alcohol to the crosslinking agent is 1:9 to 4:

6.

9. The microbial carrier as described in claim 1, characterized in that, The first repeating unit is Where R 5 and R 6 It is independently hydrogen, fluorine, methyl, or ethyl; j is 3 to 7; and k is 1 to 30.

10. The microbial carrier as described in claim 1, characterized in that, The crosslinking agent is C. 1-9 Aldehydes, aliphatic polyisocyanates, or combinations thereof.

11. The microbial carrier as described in claim 1, characterized in that, The crosslinking agent is formaldehyde, acetaldehyde, glyoxal, methylglyoxal, propionaldehyde, acrolein, malondialdehyde, butyraldehyde, valeraldehyde, glutaraldehyde, hexanal, heptanal, benzaldehyde, anisaldehyde, cuminaldehyde, or a combination thereof.

12. The microbial carrier as described in claim 1, characterized in that, The crosslinking agent is 2,4-toluene diisocyanate, 2,5-toluene diisocyanate, 2,6-toluene diisocyanate, hexamethylene diisocyanate, pentamethylene diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, 4,4'-methylene diphenyl diisocyanate, or a combination thereof.

13. A wastewater treatment device, characterized in that, Used to remove pollutants from wastewater, including: The microbial carrier according to any one of claims 1-12; and A microorganism is placed on the microbial carrier.

14. The wastewater treatment apparatus as described in claim 13, characterized in that, The pollutant is organic matter.

15. The wastewater treatment apparatus as described in claim 13, characterized in that, The pollutant is a nitrogen-containing compound.

16. The wastewater treatment apparatus as described in claim 13, characterized in that, The microorganism is an ammonia-oxidizing bacterium, an anaerobic ammonia-oxidizing bacterium, a heterotrophic bacterium, a methanogen, or a combination thereof.

17. The wastewater treatment apparatus as described in claim 13, characterized in that, The wastewater is treated by the wastewater treatment device for 10 days, and the pollutant removal rate of the wastewater treatment device is 50% to 96%.

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