An ultraviolet-coupled immobilized microorganism reactor and uses thereof

Abstract

The application discloses a kind of ultraviolet coupling immobilized microorganism reactor and its use.The main structure is quartz column reactor, inside design is ultraviolet lamp quartz sleeve, the column wall of reactor and the ultraviolet lamp quartz sleeve inside form a cavity, which is equipped with the immobilized microorganism material prepared from in-situ effluent of sewage treatment plant and sludge;The top of reactor is movable cover plate, movable cover plate is connected with aeration system, and aeration system is composed of air pump and aeration pipe, and the aeration pipe is connected with the aeration stone at the bottom of reactor.The application uses the activated sludge collected from oxidation ditch of sewage treatment plant to remove typical endocrine disruptor substances, and the removal efficiency is high.

Description

Technical Field

[0001] This invention relates to the field of reactors, and more particularly to an ultraviolet-coupled immobilized microbial reactor. Background Technology

[0002] Hormonal endocrine disruptors can have a persistent impact on aquatic organisms even at trace concentrations, and their role in causing sex reversal in animals has attracted widespread attention in recent years. Due to continuous daily production by humans and animals, as well as the large-scale production and use of synthetic compounds such as EE2, they are widely present in industrial and municipal wastewater. These compounds are typically recalcitrant organic pollutants, posing challenges to traditional biodegradation systems and creating potential threats to human health and ecological safety. Currently, researchers have developed a series of technologies for the removal of endocrine disruptors in wastewater treatment systems, including biological treatment, adsorption processes, chemical coagulation, physical filtration, advanced oxidation processes (AOPs), and electrochemical membrane treatment. These methods each have certain advantages and disadvantages in terms of removal efficiency, cost-effectiveness, and environmental sustainability. Among them, biodegradation technology has become a widely used wastewater treatment method due to its low cost and good efficiency. However, due to the complex aromatic structures of endocrine disruptors such as estrogens and androgens, traditional biodegradation processes have limited removal efficiency, necessitating the development of a series of effective bio-enhanced technologies.

[0003] Immobilized microbial technology can enhance cell tolerance to organic pollutants and their byproducts by maintaining long-term cell activity, thereby improving degradation efficiency. However, the degradation rate is still limited by the microorganisms' availability of pollutants. Advanced oxidation processes (AOPs), as a powerful means of removing recalcitrant organic compounds from aquatic environments, have been widely studied in recent years, offering advantages such as transforming recalcitrant organic matter, reducing toxicity, and producing no sludge byproducts. However, high energy consumption, difficulty in recovering catalytic particles, and incomplete mineralization are technical barriers to the widespread application of AOPs. The biological resistance and toxicity of these recalcitrant organic compounds are often attributed to their complex aromatic structures or the lack of specific degrading enzymes in the microbial community. Therefore, the technology combining biodegradation and AOPs has the potential to completely solve the problem of recalcitrant organic matter. AOPs can attack and destroy free radicals that disrupt the recalcitrant structure of target compounds, thereby altering the material structure and producing readily biodegradable products. However, simply sequentially arranging AOPs and the biodegradation process often fails to achieve ideal results because AOP products are complex and diverse, often possessing oxidizing properties, and sometimes even stronger toxicity to microorganisms than the recalcitrant target compounds.

[0004] In UV-photolysis coupled with microbial immobilization, UV light fully utilizes its advanced oxidation properties, while microorganisms simultaneously biodegrade the oxidation products into smaller molecules. UV-photolysis and biodegradation occur concurrently within the same reactor. The biodegradable products from UV-photolysis are promptly utilized by the microorganisms, preventing excessive oxidation and saving operating costs and floor space. A key aspect of this technology is the porous structure of the immobilized microbial carrier, which provides a protective mechanism for the microorganisms, preventing direct contact with the strong oxidizing products of AOPs (Activated Ortho-Oxygen Species) or cell wall rupture caused by direct UV irradiation, thus preventing cell inactivation. In particular, single-carrier microbial immobilization methods with high mechanical strength have low light transmittance, effectively blocking UV light from contacting the microorganisms. Furthermore, the large pore size on the surface of the single carrier and the interconnected internal channels facilitate the transport of oxidation products to the microorganisms. Zhang et al. used UVA irradiation and mixed bacterial biodegradation to remove debrominated diphenyl ethers in an aerobic biofilm reactor. The results showed that the reaction of the biochemical oxidation mixed microbial community was affected by continuous fermentation and ultraviolet radiation, highlighting the need to develop new materials to effectively protect and maintain cell viability. Summary of the Invention

[0005] The purpose of this invention is to provide an ultraviolet-coupled immobilized microbial reactor that has a high removal efficiency for typical endocrine disruptors.

[0006] To achieve the above objectives, the present invention provides an ultraviolet-coupled immobilized microbial reactor, characterized in that its main structure is a quartz column reactor, with an internal design of a quartz sleeve for an ultraviolet lamp. The column wall of the reactor and the internal quartz sleeve for the ultraviolet lamp form a cavity, which contains immobilized microbial material prepared from in-situ effluent and sludge from a wastewater treatment plant. The top of the reactor is a movable cover plate, which is connected to an aeration system. The aeration system consists of an air pump and an aeration pipe, which is connected to an aeration stone at the bottom of the reactor.

[0007] Furthermore, the ultraviolet lamp is a low-pressure mercury lamp capable of producing 254nm ultraviolet light.

[0008] Furthermore, the method for preparing the immobilized microbial material is as follows:

[0009] S1. Polyvinyl alcohol, sodium alginate, and kaolin are sterilized in ultrapure water under high temperature and high pressure to obtain a sterilized carrier mixture solution. This solution is stirred evenly in a sterile operating table. When the temperature drops to room temperature, 2000-3000 mg / L of mixed suspension solids is added and stirred evenly to prepare mixture A. Preferably, the ratio of polyvinyl alcohol: sodium alginate: kaolin: ultrapure water: 2000-3000 mg / L mixed suspension solids is 10±0.5g:0.3±0.05g:2.5±0.5g:100±2mL:30±2ml. The mixed suspension solids are obtained by allowing fresh raw sludge solution collected from a wastewater treatment plant to stand for 60±20 minutes, discarding the supernatant, and diluting the concentrated sludge solution to a concentration of 2000-3000 mg / L. More preferably, the concentration of the mixed suspension solids is 2400 mg / L.

[0010] S2. Transfer the obtained mixture A into a sterile syringe, remove the needle, and drip the mixture A dropwise onto a magnetic stirrer to form crosslinked spheres; the crosslinked solution is calcium chloride and boric acid dissolved in ultrapure water; preferably, the ratio of ultrapure water: calcium chloride: boric acid is 1L:40g:30g; preferably, the stirring speed is 500±50rpm / min;

[0011] S3. Transfer the contents of S2 to an Erlenmeyer flask and place it in a constant temperature incubator for cross-linking and hardening; preferably, the cross-linking and hardening conditions are 22-24 h, 30 °C, and 200 r / min.

[0012] S4. Wash the material obtained from S3 with sterile ultrapure water, and then transfer it to sterile R2A culture medium for activation for 24-48 hours to obtain immobilized microbial material.

[0013] This invention also protects the use of the ultraviolet-coupled immobilized microbial reactor for the removal of endocrine disruptors.

[0014] Furthermore, the endocrine disruptor is testosterone.

[0015] The present invention also protects a method for removing endocrine disruptors, characterized by the use of the aforementioned ultraviolet-coupled immobilized microbial reactor.

[0016] Further, this includes adding testosterone to the ultraviolet-coupled immobilized microbial reactor, such that the concentration of testosterone is 2±0.1 mg / L, and reacting for 0.5-6 hours, preferably 0.5-4 hours.

[0017] In this invention, activated sludge from oxidation ditches in wastewater treatment plants is collected and immobilized in cellulose acetate material, then applied to a continuous-flow operation for the intermittent degradation of endocrine disruptors in an ICPB photoreactor. Compared to pure bacterial systems, activated sludge exhibits higher community diversity; therefore, this invention selects activated sludge from wastewater treatment plants for immobilization, combining it with an ultraviolet photodegradation reactor to explore the removal efficiency of typical endocrine disruptors through the combination of AOPs and biodegradation. Simultaneously, the activated sludge waste is utilized, making it more environmentally friendly and cost-effective.

[0018] The degradation efficiency of endocrine disruptors by UV-coupled immobilized activated sludge is higher than that of UV degradation alone and immobilized activated sludge alone. Nearly half of the removal efficiency is achieved in the initial stage of the coupled reaction. This result may be due to the rapid initial action of UV photodegradation compared to the relatively slow biodegradation process. Subsequently, due to the protective effect of the immobilized material on the functional microorganisms in the activated sludge, these microorganisms can continue to exert their degradation effect in the later stages, thus ensuring that the UV-coupled immobilized activated sludge technology achieves optimal removal of endocrine disruptors. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of an ultraviolet-coupled immobilized microbial reactor.

[0020] Figure 2 This is a diagram showing the results of testosterone degradation by ultraviolet-coupled immobilized materials. Detailed Implementation

[0021] The embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention. Where specific techniques or conditions are not specified in the embodiments, they are performed according to the techniques or conditions described in the literature in the art or according to the product instructions. Reagents or instruments used, unless otherwise specified, are all conventional products that can be obtained commercially.

[0022] Example 1: Preparation of an ultraviolet-coupled immobilized microbial reactor

[0023] 1. Design of UV-coupled immobilized microbial reactor

[0024] UV-coupled immobilized microbial reactors, such as Figure 1As shown. The main structure of the reactor is a quartz column reactor with an effective volume of 1L. The interior is designed with a quartz sleeve for an ultraviolet lamp, which is a low-pressure mercury lamp that can produce 254nm ultraviolet light. The reactor column wall and the internal quartz sleeve for the ultraviolet lamp form a cavity, into which the immobilized microbial material is added. The cavity contains in-situ effluent from the wastewater treatment plant. The top of the reactor has a movable cover plate, which can be opened and connected to the aeration system. The aeration system consists of an air pump and aeration pipes. The aeration pipes are connected to the aeration stones at the bottom of the reactor for aeration, with an aeration rate of 0.3L / min.

[0025] The amount of immobilized microbial material is determined by the volume of the reactor (i.e., the volume of the chamber) and the effectiveness of ultraviolet light irradiation. For example, if the reactor volume is 1L, adding 30-50g will occupy approximately 1 / 10 of the height of the column reactor (it can be at 1 / 5 to 1 / 10). Considering both ensuring the effectiveness of ultraviolet light irradiation and relying on sufficient functional microorganisms in activated sludge, 30-50g can be added.

[0026] 2. Preparation of immobilized microbial materials by mixing activated sludge

[0027] Fresh raw sludge solution (moisture content >95%) was collected from the wastewater treatment plant and stored in an amber glass bottle at 4℃. After being brought back to the laboratory and allowed to stand for 60 minutes, the supernatant was discarded, and 80 ml of the concentrated sludge solution was diluted to a mixed suspension with a concentration of 2400 mg / L. Immobilized microbial materials were then prepared using a composite carrier method, as detailed below:

[0028] (1) Weigh 10g of polyvinyl alcohol, 0.3g of sodium alginate and 2.5g of kaolin into a 200mL beaker, add 100mL of ultrapure water, seal with tin foil and sterilize under high temperature and high pressure (121℃, 15min) to obtain a sterilized carrier mixture solution. Stir it evenly in a sterile operating table. When the temperature drops to room temperature, add 30ml of 2400mg / L mixed solution suspension solid and stir evenly to prepare mixed solution A.

[0029] (2) Preparation of crosslinking solution: Add 40g of calcium chloride and 30g of boric acid to 1L of ultrapure water. After they are completely dissolved, sterilize by high temperature and high pressure (121℃, 15min).

[0030] (3) Place the sterile crosslinking solution on a magnetic stirrer and stir at a constant speed of 500 r / min. Transfer the mixture A into a sterile syringe, remove the needle, and allow the mixture A to be added drop by drop into the crosslinking solution at a constant speed to crosslink into spheres.

[0031] (4) Transfer the contents of step (3) into an Erlenmeyer flask and place it in a constant temperature incubator for cross-linking and hardening. The cross-linking and hardening conditions are 22-24h, 30℃, and 200r / min.

[0032] (5) Wash the surface cross-linking agent of the immobilized microbial particles on the composite carrier with sterile ultrapure water, and then transfer them to 250 mL of sterile R2A culture medium (0.05% (w / v) yeast extract, 0.05% peptone, 0.05% tyrosine, 0.05% glucose, 0.05% starch, 0.03% sodium pyruvate, pH 7.2) for activation for 24-48 h to obtain immobilized microbial material (small spheres or discs) for later use.

[0033] 3. Preparation of UV-coupled immobilized microbial reactors

[0034] The small spherical or disc-shaped immobilized microbial material containing activated sludge formed in step (5) above can be directly added into the cavity of the reactor.

[0035] Open the movable cover at the top of the reactor and add the immobilized microbial material containing activated sludge to the liquid (500 ml of in-situ effluent from the wastewater treatment plant) between the UV lamp and the reactor column wall. Since the column reactor has a volume of 1 L, adding 30-50 g will approximately fill 1 / 10 of the column reactor in height. Considering both ensuring the effectiveness of UV illumination and relying on sufficient functional microorganisms from the activated sludge, 30-50 g is added.

[0036] Example 2:

[0037] Taking the removal of androgens—testosterone—as an example, testosterone at a final concentration of 2 mg / L was added to the reactor liquid. This embodiment included an experimental group and a control group. The reactors for the experimental group and the control group were as follows:

[0038] The experimental group reactors were equipped with immobilized activated sludge material. The control group reactors were equipped with blank immobilized material (Control 1), no UV light, UV light (Control 2), and no immobilized material (Control 3). Specifically:

[0039] Control 1 (blank carrier): The reactor was only added with blank immobilization material (the immobilized microspheres were prepared according to the preparation of immobilized microbial materials, except that the activated sludge suspension was replaced with an equal volume of sterile water), and there was no ultraviolet lamp.

[0040] Control 2 (Immobilized Carrier): The reactor contained only the immobilized microbial material obtained in step 2 of Example 1, without a UV lamp.

[0041] Control 3 (UV and blank support): The reactor only uses UV light and no immobilization materials are added.

[0042] Experimental group (UV and immobilized carrier): The UV-coupled immobilized microbial reactor of the present invention was used, that is, UV was used, and the activated sludge prepared in step 2 of Example 1 was added to prepare immobilized microbial material.

[0043] The total dosage of immobilized activated sludge granules was 30 g. The reaction was carried out at room temperature (25±2℃) with constant stirring. Samples were collected from stainless steel sampling tubes using a sterile syringe at 0, 0.5, 1, 2, 4, 8, and 24 hours. After liquid-liquid extraction with an equal volume of diethyl ether, the testosterone content in the samples was quantitatively analyzed by high-performance liquid chromatography (HPLC). The results are shown in the figure. Figure 2 The chromatographic column used was a C18 column (3.05 mm, 2.2 μm). The gradient elution program was as follows: mobile phase: phase A was water, phase B was acetonitrile; flow rate: 0.5 mL / min; gradient elution program: initial concentration of phase B was 24%, held for 2 min, increased to 45% at min 3, held for 1.5 min, increased to 45% at min 7, increased to 55% at min 8, held for 0.5 min, and decreased to 22% at min 8.7. Figure 2 It can be seen that the UV-coupled immobilized microbial reactor of this invention has the best effect on degrading testosterone. After the degradation begins, the testosterone concentration decreases significantly over time, and almost all testosterone is degraded by 4 hours, with the testosterone concentration approaching 0. Although the testosterone concentration in controls 2 and 3 also decreases over time, it is far from reaching the effect of the experimental group. In control 1, the testosterone concentration decreases slightly in the 0-1 hour range, increases in the 1-2 hour range, and shows a slight decreasing trend in the 2-8 hour range.

[0044] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention without departing from the principles and spirit of the present invention.

Claims

1. A UV-coupled immobilized microbial reactor, characterized in that, Its main structure is a quartz column reactor with an internal quartz sleeve for ultraviolet lamps. The column wall of the reactor and the internal quartz sleeve for ultraviolet lamps form a cavity, which contains in-situ effluent from wastewater treatment plants and immobilized microbial materials prepared from sludge. The top of the reactor is a movable cover plate, which is connected to the aeration system. The aeration system consists of an air pump and aeration pipes, which are connected to the aeration stones at the bottom of the reactor. The method for preparing the immobilized microbial material is as follows: S1. Take polyvinyl alcohol, sodium alginate and kaolin in ultrapure water and sterilize them under high temperature and high pressure to obtain a sterilized carrier mixture solution. Stir it evenly in a sterile operating table. When the temperature drops to room temperature, add 2000-3000 mg / L of the mixture suspension solid and stir evenly to prepare mixture A. S2. Transfer the obtained mixture A into a sterile syringe, remove the needle, and drip the mixture A into the crosslinking solution being stirred at a constant speed on a magnetic stirrer to crosslink into spheres; the crosslinking solution is calcium chloride and boric acid dissolved in ultrapure water; S3. Transfer the contents of S2 to an Erlenmeyer flask and place it in a constant temperature incubator for cross-linking and hardening; S4. Wash the material obtained from S3 with sterile ultrapure water, and then transfer it to sterile R2A culture medium for activation for 24-48 hours to obtain immobilized microbial material.

2. The ultraviolet-coupled immobilized microbial reactor as described in claim 1, characterized in that, The ultraviolet lamp in the quartz sleeve is a low-pressure mercury lamp that can produce 254nm ultraviolet light.

3. The ultraviolet-coupled immobilized microbial reactor as described in claim 1, characterized in that, In step S1, the ratio of polyvinyl alcohol, sodium alginate, kaolin, ultrapure water, and 2000-3000 mg / L of the mixed suspension of solids is 10±0.5g:0.3±0.05g:2.5±0.5g:100±2mL:30±2ml. The mixed suspension of solids is obtained by letting fresh raw sludge solution collected from the sewage treatment plant stand for 60±20 minutes, discarding the supernatant, and diluting the concentrated sludge solution to a concentration of 2000-3000 mg / L.

4. The ultraviolet-coupled immobilized microbial reactor as described in claim 3, characterized in that, In step S1, the concentration of suspended solids in the mixture is 2400 mg / L.

5. The ultraviolet-coupled immobilized microbial reactor as described in claim 1, characterized in that, In step S2, the ratio of ultrapure water: calcium chloride: boric acid is 1L:40g:30g.

6. The ultraviolet-coupled immobilized microbial reactor as described in claim 1, characterized in that, In step S2, the stirring speed is 500±50 rpm / min.

7. The ultraviolet-coupled immobilized microbial reactor as described in claim 1, characterized in that, The cross-linking and hardening conditions in step S3 are 22–24 h, 30 °C, and 200 r / min.

8. Use of the ultraviolet-coupled immobilized microbial reactor according to any one of claims 1-7 for the removal of endocrine disruptors.

9. The use as described in claim 8, characterized in that, The endocrine disruptor is testosterone.

10. A method for removing endocrine disruptors, characterized in that, The UV-coupled immobilized microbial reactor according to any one of claims 1-7 was used.

11. The method for removing endocrine disruptors as described in claim 10, characterized in that, This includes adding testosterone to the UV-coupled immobilized microbial reactor according to any one of claims 1-7, wherein the concentration of testosterone after addition is 2±0.1 mg / L, and the reaction time is 0.5-6 hours.

12. The method for removing endocrine disruptors as described in claim 10, characterized in that, The reaction time is 0.5-4 hours.

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