Biological carrier for enhancing enrichment and activity of anaerobic ammonium oxidation bacteria, preparation method therefor, and use thereof

Abstract

The present invention belongs to the technical field of sewage treatment. Disclosed are a biological carrier for enhancing enrichment and activity of anaerobic ammonium oxidation bacteria, a preparation method therefor, and a use thereof. In the present invention, a functional biological carrier suitable for anaerobic ammonium oxidation is prepared by blending polyethylene or polypropylene as a basic raw material, a positively charged polymer such as a polyquaternary ammonium salt or a cationic polyacrylamide as a modifying material, and zero-valent iron and a carbon-based material containing C=O and -COOH functional groups as functional materials. The biological carrier of the present invention can enhance the enrichment and metabolic activity of the anaerobic ammonium oxidation bacteria, thereby improving the nitrogen removal efficiency.

Description

A biological carrier for enhancing the enrichment and activity of anaerobic ammonium-oxidizing bacteria, and its preparation method and application Technical Field

[0001] The present invention belongs to the technical field of sewage treatment, and specifically relates to a biological carrier for enhancing the enrichment and activity of anaerobic ammonia-oxidizing bacteria, and a preparation method and application thereof. Background Art

[0002] Excessive nitrogen discharge can lead to eutrophication of water bodies, and the government has strictly controlled the discharge of ammonia nitrogen and total nitrogen in wastewater. Traditional denitrification processes are biological denitrification processes involving nitrification and denitrification. These processes require extensive aeration and the addition of additional carbon sources, increasing operating costs. Under the dual-carbon policy, the development of efficient and cost-effective denitrification technologies has become a major need in the wastewater treatment sector. Anaerobic ammonium oxidation (ANAMMOX) is a novel autotrophic denitrification technology. Combined with partial nitrification, it achieves highly efficient denitrification. The entire denitrification process not only eliminates the need for additional carbon sources but also reduces aeration volumes by 60%, significantly lowering operating costs. However, the long doubling time and slow growth rate of ANAMMOX bacteria, along with their susceptibility to environmental influences, limit their large-scale application. The biofilm method, due to the presence of biological carriers, can increase sludge age, improve volumetric loading, and effectively enrich ANAMMOX bacteria, making it an effective means of achieving ANAMMOX in mainstream urban wastewater. In particular, the Moving Bed Membrane Bioreactor based on suspended carriers and the Integrated floating-film and activated sludge process based on suspended carriers have overcome the shortcomings of the fixed biofilm process, such as low mass transfer efficiency and easy congestion and agglomeration, and have good denitrification performance, thus being widely used. However, the biofilm formation time of anaerobic ammonium oxidizing bacteria on traditional suspended bio-carriers is long, the biomass of the membrane is small, and traditional suspended bio-carriers cannot improve the metabolic activity of anaerobic ammonium oxidizing bacteria. Therefore, there is an urgent need to develop a bio-carrier for anaerobic ammonium oxidizing bacteria to enhance the enrichment and activity of anaerobic ammonium oxidizing bacteria, and ultimately achieve the goal of efficient and economical denitrification.

[0003] Summary of the Invention

[0004] To address the technical issues of poor anaerobic ammonium oxidizing (ANAMMOX) bacterial enrichment and low denitrification activity on traditional biocarriers, the present invention aims to provide a biocarrier that enhances ANAMMOX bacterial enrichment and activity, as well as its preparation method and application. This invention utilizes polyethylene or polypropylene as a base material, positively charged polymers such as polyquaternary ammonium salts and cationic polyacrylamide as a modifying material, and zero-valent iron and carbon-based materials containing C=O and -COOH functional groups as functional materials. A functional ANAMMOX biocarrier is prepared by blending these materials. The positively charged polymers, such as polyquaternary ammonium salts and cationic polyacrylamide, enhance the attachment of ANAMMOX bacteria to the carrier; the zero-valent iron enhances the bacterial proliferation and intracellular metabolic rate; and the carbon-based materials containing -C=O and -COOH functional groups mediate and enhance the extracellular electron transfer of ANAMMOX bacteria. These factors, combined, enhance the enrichment and biological activity of ANAMMOX bacteria on the biocarrier, ultimately achieving efficient and economical denitrification.

[0005] In order to achieve the above object, the present invention provides the following technical solutions:

[0006] A biological carrier for enhancing the enrichment and activity of anaerobic ammonium-oxidizing bacteria, wherein the biological carrier is prepared by blending a basic material with a modified material and / or a functional material; the added amount of the modified material and / or the functional material does not exceed 10% of the total mass of the basic material.

[0007] Based on the above technical solution, further, the base material is polyethylene or polypropylene; the modified material is a positively charged polymer such as polyquaternary ammonium salt, cationic polyacrylamide, etc., which enhances the biofilm formation of anaerobic ammonia-oxidizing bacteria through electrostatic force; the functional material is one or a mixture of zero-valent iron, a carbon-based material containing -C=O and -COOH functional groups, and enhances the enrichment and activity of anaerobic ammonia-oxidizing bacteria by enhancing the anaerobic microenvironment, intracellular metabolism and extracellular electron transfer.

[0008] Based on the above technical solution, further, the carbon-based material containing -C=O and -COOH functional groups includes graphene oxide and activated carbon and biochar rich in oxygen-containing functional groups or that have been oxidized.

[0009] Another aspect of the present invention provides a method for preparing the above-mentioned biological carrier for enhancing the enrichment and activity of anaerobic ammonium-oxidizing bacteria, comprising the following steps:

[0010] (1) Weighing the basic raw materials, modified materials, and functional materials according to the proportions to obtain a mixture;

[0011] (2) mixing the mixture in step (1) in a stirring mixer to obtain a mixed material;

[0012] (3) placing the mixed material in step (2) in a granulator to be processed into a strip material, and then cutting it into granular materials by a cutting machine;

[0013] (4) The granular material in step (3) is placed in an injection molding machine, and pipes of different shapes are made according to the selected mold head, and are cut to the required size.

[0014] Based on the above technical solution, further, in step (3), the temperature of the barrel zone and the head zone of the granulator are maintained at 150-190°C.

[0015] Based on the above technical solution, further, the processing temperature of the injection molding machine in step (4) is 120-190°C.

[0016] The present invention also provides the use of the above-mentioned biological carrier for enhancing the enrichment and activity of anaerobic ammonium-oxidizing bacteria in sewage denitrification.

[0017] Based on the above technical solution, further, the biological carrier improves the efficiency of sewage denitrification by enhancing the enrichment and activity of anaerobic ammonium-oxidizing bacteria.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] (1) During the growth and metabolism of anaerobic ammonium oxidizing bacteria, iron participates in the synthesis of five key enzymes and cytochrome c in the cells of anaerobic ammonium oxidizing bacteria. The key enzymes are nitrite reductase (NirS), hydrazine synthase (HZS), hydrazine oxidoreductase (HZO), hydrazine dehydrogenase (HDH), and hydroxylamine oxidoreductase (HAO). They work together to convert ammonia nitrogen and nitrite nitrogen into nitrogen gas; cytochrome c is a mediator of intracellular electron transfer and participates in most intracellular metabolic reactions; the additional addition of zero-valent iron material to the anaerobic ammonium oxidizing system can enhance the synthesis of the above five key enzymes and cytochrome c, thereby enhancing the growth and metabolism of anaerobic ammonium oxidizing bacteria; in addition, zero-valent iron can also reduce the dissolved oxygen and redox potential in water, providing a good environment for the growth and metabolism of anaerobic ammonium oxidizing bacteria.

[0020] (2) Anaerobic ammonium oxidizing bacteria have the ability to transfer extracellular electrons, transferring intracellular electrons to extracellular insoluble electron acceptors through cytochrome c. Carbon-based materials containing -C=O and -COOH functional groups can use their own redox ability to accept and transfer electrons because they have -C=O and -COOH functional groups. Therefore, they can serve as insoluble electron acceptors outside the cells of anaerobic ammonium oxidizing bacteria. The π electrons inside graphene oxide form a π-π conjugated structure with the π electrons of oxygen-containing functional groups such as -C=O on the edge. It has an electron mediator function similar to quinone-hydroquinone and can mediate and enhance extracellular electron transfer through the cycle of -C=O and -C-OH functional groups. This extracellular electron transfer accelerates the metabolism of anaerobic ammonium oxidizing bacteria, thereby enhancing the enrichment and activity of anaerobic ammonium oxidizing bacteria. Therefore, exogenous addition of carbon-based materials containing -C=O and -COOH functional groups can mediate and promote extracellular electron transfer, thereby enhancing the enrichment and activity of anaerobic ammonium oxidizing bacteria.

[0021] (3) The surface of anaerobic ammonium oxidizing bacteria carries a negative charge. Positively charged polymers such as polyquaternary ammonium salts and cationic polyacrylamide can produce electrostatic adsorption with anaerobic ammonium oxidizing bacteria, thereby enhancing the enrichment of bacteria. DETAILED DESCRIPTION

[0022] The present invention is described in detail below with reference to the embodiments, but the embodiments of the present invention are not limited thereto. Obviously, the embodiments described below are only some embodiments of the present invention. For those skilled in the art, other similar embodiments obtained without creative work all fall within the scope of protection of the present invention.

[0023] Example 1

[0024] 1000g of HDPE powder and 50g of zero-valent iron were thoroughly mixed in a sealed container to form raw material 1. Raw material 1 was passed through a pelletizer to produce a granular sample. The pelletizer's barrel zone 1 was set at 160°C, the barrel zone 2 was set at 170°C, the barrel zone 3 was set at 180°C, and the die zone was set at 160°C. The strip product extruded from the die was then air-cooled and pelletized to produce a granular sample (referred to as raw material 2). Raw material 2 was passed through an injection molding machine to produce a carrier. The barrel zone 1 was set at 140°C, the barrel zone 2 was set at 150°C, the barrel zone 3 was set at 155°C, and the die zone was set at 140°C. The strip product extruded from the die was then shaped and sized using a vacuum setting sleeve with a vacuum degree of 0.03MPa, cooled with cooling water, and cut into cylindrical products, the final anaerobic ammonium oxidation biocarrier.

[0025] In the absence of organic carbon source, temperature 30℃, pH 8.0, influent ammonia nitrogen 150mg / L, influent nitrate nitrogen 198mg / L, hydraulic retention time 12h, filler filling rate 30%, surface total nitrogen load 3.25g TN / (m 2In the mud film system of d), the biofilm amount of anaerobic ammonium oxidizing bacteria on the carrier is 1.59g / m 2 , which is 2.48 times that of traditional carriers; the denitrification efficiency is increased by about 15% compared with traditional HDPE carriers.

[0026] Example 2

[0027] 1000g of HDPE powder and 5g of graphene oxide were thoroughly mixed in a sealed container to form raw material 1. Raw material 1 was passed through a granulator to produce a granular sample, wherein the granulator barrel zone 1 was 160°C, the barrel zone 2 was 170°C, the barrel zone 3 was 180°C, and the die zone was 160°C. The strip product extruded from the die head was then air-cooled and pelletized to form a granular sample (referred to as raw material 2). Raw material 2 was passed through an injection molding machine to produce a carrier, wherein the injection molding machine barrel zone 1 was 140°C, the barrel zone 2 was 150°C, the barrel zone 3 was 155°C, and the die zone was 140°C. The strip product extruded from the die head was then shaped and sized with a vacuum set at a vacuum degree of 0.03MPa, cooled with cooling water, and cut into a cylindrical product, namely the anaerobic ammonium oxidation biological carrier.

[0028] In the absence of organic carbon source, temperature 30℃, pH 8.0, influent ammonia nitrogen 150mg / L, influent nitrate nitrogen 198mg / L, hydraulic retention time 12h, filler filling rate 30%, surface total nitrogen load 3.25g TN / (m 2 In the mud film system of d), the biofilm amount of anaerobic ammonium oxidizing bacteria on the carrier is 1.68g / m 2 , which is about 2.62 times that of traditional carriers; the denitrification efficiency is increased by about 15% compared with traditional HDPE carriers.

[0029] Example 3

[0030] 1000g of HDPE powder, 10g of polyquaternium salt, and 50g of zero-valent iron were thoroughly mixed in a sealed container to form raw material 1. Raw material 1 was passed through a pelletizer to produce a granular sample. The pelletizer's barrel zone 1 was set at 160°C, the barrel zone 2 was set at 170°C, the barrel zone 3 was set at 180°C, and the die zone was set at 160°C. The strip product extruded from the die was then air-cooled and pelletized to produce a granular sample (referred to as raw material 2). Raw material 2 was passed through an injection molding machine to produce a carrier. The barrel zone 1 was set at 140°C, the barrel zone 2 was set at 150°C, the barrel zone 3 was set at 155°C, and the die zone was set at 140°C. The strip product extruded from the die was then shaped and sized using a vacuum setting sleeve with a vacuum degree of 0.03MPa, cooled with cooling water, and cut into cylindrical products, which were the final anaerobic ammonium oxidation bio-carriers.

[0031] In the absence of organic carbon source, temperature 30℃, pH 8.0, influent ammonia nitrogen 150mg / L, influent nitrate nitrogen 198mg / L, hydraulic retention time 12h, filler filling rate 30%, surface total nitrogen load 3.25g TN / (m2 In the mud film system of d), the biofilm amount of anaerobic ammonium oxidizing bacteria on the carrier is 1.71g / m 2 , which is about 2.67 times that of traditional carriers; the denitrification efficiency is increased by about 17% compared with traditional HDPE carriers.

[0032] Example 4

[0033] 1000g of HDPE powder, 10g of polyquaternium salt, 50g of zero-valent iron, and 5g of graphene oxide were thoroughly mixed in a sealed container to form raw material 1. Raw material 1 was passed through a pelletizer to produce a granular sample. The pelletizer's barrel zone 1 was set at 160°C, the barrel zone 2 was set at 170°C, the barrel zone 3 was set at 180°C, and the die zone was set at 160°C. The strip product extruded from the die was then air-cooled and pelletized to produce a granular sample (referred to as raw material 2). Raw material 2 was passed through an injection molding machine to produce a carrier. The barrel zone 1 was set at 140°C, the barrel zone 2 was set at 150°C, the barrel zone 3 was set at 155°C, and the die zone was set at 140°C. The strip product extruded from the die was then shaped and sized using a vacuum setter with a vacuum degree of 0.03MPa, cooled with cooling water, and cut into cylindrical products, which were the finished anaerobic ammonium oxidation biocarriers.

[0034] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A biological carrier for enhancing the enrichment and activity of anaerobic ammonium-oxidizing bacteria, characterized in that: The bio-carrier is prepared by blending a basic material with a modified material or / and a functional material; the added amount of the modified material or / and the functional material does not exceed 10% of the total mass of the basic material.

2. According to the biological carrier for enhancing the enrichment and activity of anaerobic ammonium-oxidizing bacteria according to claim 1, the base material is polyethylene or polypropylene; the modified material is a positively charged polymer such as polyquaternary ammonium salt, cationic polyacrylamide, etc.; the functional material is one or a mixture of zero-valent iron, a carbon-based material containing -C=O and -COOH functional groups.

3. The biological carrier for enhancing the enrichment and activity of anaerobic ammonium-oxidizing bacteria according to claim 2, characterized in that: The carbon-based materials containing -C=O and -COOH functional groups include graphene oxide and activated carbon and biochar that are rich in oxygen-containing functional groups or have been oxidized.

4. The method for preparing a biological carrier for enhancing the enrichment and activity of anaerobic ammonia-oxidizing bacteria according to any one of claims 1 to 3, characterized in that: The following steps are involved: (1) Weighing the basic material, modified material, and functional material according to the proportion to obtain a mixture; (2) mixing the mixture in step (1) in a stirring mixer to obtain a mixed material; (3) placing the mixed material in step (2) in a granulator to be processed into a strip material, and then cutting it into granular materials by a cutting machine; (4) The granular material in step (3) is placed in an injection molding machine, and pipes of different shapes are made according to the selected mold heads, and then cut to the required size.

5. The preparation method according to claim 4, characterized in that: In step (3), the temperature of the barrel zone and the head zone of the granulator are maintained at 150-190°C.

6. The preparation method according to claim 4, characterized in that: The processing temperature of the injection molding machine in step (4) is 120-190°C.

7. Use of the biological carrier for enhancing the enrichment and activity of anaerobic ammonium-oxidizing bacteria as described in any one of claims 1 to 3 in wastewater denitrification.

8. The use according to claim 7, characterized in that: The biological carrier improves the efficiency of sewage denitrification by enhancing the enrichment and activity of anaerobic ammonium oxidizing bacteria.