A method for preparing a sewage treatment element based on 3D printing and application thereof

Abstract

This application belongs to the field of wastewater treatment, specifically relating to a method for preparing and applying a wastewater treatment element based on 3D printing. The specific steps are as follows: S1. Mix 40%–45% unsaturated monomer, 3%–5% crosslinking agent, 0.5%–0.8% aqueous photoluminescent agent, and 0.2%–0.3% light absorber by mass fraction, with the remainder being water, and filter through a membrane filter to obtain a basic hydrogel ink for later use; S2. Dissolve microorganisms in water, then filter through a membrane filter, and add the microorganisms from the membrane filter to a glucose solution and let it stand to obtain a microbial glucose solution for later use; S3. Mix the basic hydrogel ink prepared in S1 with the microbial glucose solution prepared in S2, place in a sealed space, fill with oxygen, and mechanically vibrate to obtain a bio-ink; S4. Use 3D printing technology to obtain the wastewater treatment element. This application develops a 3D-printed wastewater treatment element that can be used quickly, simply, and efficiently for wastewater treatment.

Description

Technical Field

[0001] This application belongs to the field of wastewater treatment, specifically relating to a method for preparing wastewater treatment elements based on 3D printing and its application. Background Technology

[0002] Wastewater from thermal power plants mainly comes from boiler cooling water, boiler wastewater, and flue gas desulfurization wastewater. This wastewater contains large amounts of suspended solids, heavy metals, organic matter, and inorganic salts, among other harmful substances. Direct discharge into the environment will pollute water quality and adversely affect surrounding soil and vegetation. Wastewater treatment from thermal power plants is a pressing issue in current production processes, as improper treatment can have significant environmental impacts. Therefore, efficient wastewater treatment and improving water quality are crucial aspects of wastewater management. Common wastewater treatment technologies, primarily focused on reducing COD, include physical, microbial, chemical, and electrochemical methods. Among these, microbial treatment is a vital and widely used technology. This is because microorganisms have a high degradation capacity, rapidly degrading organic matter and other pollutants in wastewater, thus improving treatment efficiency. Furthermore, microbial wastewater treatment generates minimal waste, making it a sustainable wastewater treatment technology that effectively reduces the consumption of natural resources and has a smaller environmental impact. Microbial treatment not only removes organic matter, pathogens, and toxic substances but also eliminates odors, improves transparency, and reduces color, demonstrating excellent treatment results. However, in microbial treatment, regardless of the specific approach employed, two core issues remain. First, the inoculation, acclimatization, and reproduction of microorganisms are crucial; the presence of a suitable microbial community is fundamental to achieving good treatment results. Second, a suitable carrier for microbial growth, namely the packing material, is essential. Only when microorganisms attach and grow on the surface of the packing material—that is, when a biofilm forms—can continuous biochemical reactions occur, leading to wastewater purification. Currently, the energy required for the respiration, metabolism, growth, and reproduction of microorganisms is provided by the wastewater. This results in a lengthy and complex process for the microbial population to grow from inoculation to a sufficient number. Furthermore, packing materials are typically polyhedral spatial structures made of organic materials, and the implantation and biofilm formation of microorganisms on their surface also require time. Moreover, this biofilm is easily detached. Since the packing material does not contain nutrients, it cannot provide the energy needed for microbial growth, thus failing to promote microbial growth, reproduction, and metabolism.

[0003] Chinese Patent CN206735917U discloses a microbial filtration membrane wastewater treatment device, including a tank with an inlet at one end and an outlet on the side of the other end. A microbial filtration membrane is installed inside the tank, and a microbial culture bed is located on one side of the membrane. This invention utilizes microbial strains cultivated in the culture bed, which continuously enter the microbial filtration membrane with the water flow, providing and replenishing the membrane for wastewater purification. This effectively avoids the depletion of microorganisms on the membrane. However, in this application, the nutrients required for microbial growth in the culture bed mainly come from wastewater, making it difficult to guarantee stable microbial growth.

[0004] Chinese patent CN113248004B discloses a method for preparing a microbial carrier for wastewater treatment. This application uses wooden spherical cages added to a polyethylene spherical membrane to prevent the polyvinyl alcohol resin from shrinking and cracking during cooling, thus losing its function of creating cavities inside the polyvinyl alcohol resin. At the same time, cellulase mixed in with microbial powder can decompose the wooden spherical cages with the microorganisms during wastewater treatment, providing the microorganisms with an additional glucose source and enhancing their metabolic activity. However, the preparation process of this application is complex and involves many additives, which may affect the activity of the microorganisms.

[0005] 3D printing technology is a technique that uses digital model files as a basis and employs powdered metal or plastic and other bondable materials to construct objects by printing layer by layer. It has been widely used in medical, food processing, aerospace, cultural relic restoration, and construction due to its unique processing method, but it has not yet been used in the field of microbial wastewater treatment.

[0006] In summary, given the current state of the technology, the microbial reproduction process in wastewater treatment is a lengthy and complex process. Conventional methods struggle to provide the necessary nutrients and stable environment for microbial growth. Furthermore, packing materials are typically polyhedral spatial structures made of organic materials, requiring considerable time for microbial populations to attach, grow, and form biofilms. These biofilms are also prone to detachment. Since packing materials lack nutrients, they cannot provide the energy required for microbial growth, thus failing to promote microbial growth, reproduction, and metabolism. Therefore, this application provides a method for preparing wastewater treatment components based on 3D printing and its application. Summary of the Invention

[0007] In view of the current situation in the background technology, the microbial reproduction process in wastewater treatment is a relatively long and complex environment. Furthermore, the packing material is generally a polyhedral spatial structure made of organic materials, and it takes time for microbial populations to attach, grow, and form a biofilm on its surface. Moreover, this biofilm is also relatively easy to detach. The packing material does not contain nutrients, so it cannot provide the energy required for microbial growth. Therefore, this application provides a method for preparing wastewater treatment components based on 3D printing and its application.

[0008] The technical solution of this application is as follows:

[0009] On the one hand, this application provides a method for preparing wastewater treatment elements based on 3D printing, specifically including the following steps:

[0010] S1. Preparation of basic hydrogel ink: Mix 40%–45% unsaturated monomer, 3%–5% crosslinking agent, 0.5%–0.8% aqueous photoluminescent agent and 0.2%–0.3% light absorber with the balance of water, and filter through a membrane filter to obtain basic hydrogel ink for later use;

[0011] S2. Preparation of microbial glucose solution: Dissolve microorganisms in water, then filter through a membrane filter, and add the microorganisms on the membrane filter to the glucose solution and let it stand to obtain microbial glucose solution for later use;

[0012] S3. Preparation of bio-ink: The basic hydrogel ink prepared in S1 is mixed with the microbial glucose solution prepared in S2, placed in a closed space, filled with oxygen, and mechanically shaken to obtain bio-ink;

[0013] S4. Preparation of wastewater treatment elements: The bio-ink prepared in S3 was used to obtain wastewater treatment elements using 3D printing technology.

[0014] In one specific implementation, the unsaturated monomer in S1 is an acrylamide polymer.

[0015] In one specific implementation, the acrylamide polymer is hydroxyethylacrylamide.

[0016] In one specific implementation, the crosslinking agent in S1 is polyethylene glycol dimethacrylate.

[0017] In one specific implementation scheme, the aqueous photoluminescent agent in S1 is polyethylene glycol.

[0018] In one specific implementation, the light absorber in S1 is riboflavin; the pore size of the membrane filter is 0.22 μm.

[0019] In one specific implementation scheme, the pore size of the filter membrane in S2 is 0.45 μm, the mass fraction of the glucose solution is 2%, the mass ratio of the microorganisms to the glucose solution is 1:15, and the settling time is 48 h.

[0020] In one specific implementation scheme, the mass ratio of the basic hydrogel ink to the microbial glucose solution in S3 is 30:1, and when the bio-ink obtained by filling with oxygen and mechanically shaking becomes turbid and opaque, it is the desired bio-ink.

[0021] In one specific implementation, the 3D printing conditions described in S4 are blue light with a wavelength of 400nm and an intensity of 50mw.

[0022] On the other hand, this application provides an application of a 3D printing-based wastewater treatment element preparation method for wastewater treatment.

[0023] The beneficial effects of this application are:

[0024] This application creatively develops a 3D-printed wastewater treatment element that can be used quickly, simply, and efficiently for wastewater treatment. Before preparing the printing ink, the microorganisms are activated in a glucose solution for a period of time, improving their survival rate in the ink. Simultaneously, before printing, excess oxygen is introduced into the ink to form a microbubble structure, providing the necessary nutrients and space for microbial survival. Furthermore, the multi-faceted, porous structure created by 3D printing provides excellent conditions for mass and energy transfer. Because the nutrients for microbial survival in this wastewater treatment element do not entirely depend on organic matter in the wastewater, it exhibits extremely high tolerance to fluctuations in wastewater quality. Unlike traditional biofilms that only grow on the surface of the packing material, the microorganisms in this application are evenly distributed throughout the entire wastewater treatment element. This wastewater treatment element represents a symbiotic coexistence of active microorganisms and their carrier. When this microbial element is introduced into wastewater, it can immediately initiate a biochemical reaction, overcoming the slow start-up time of existing wastewater treatment methods (currently, the start-up time is approximately 7 days). More promisingly, it can be effectively applied in situations where water quality is severely polluted. Attached Figure Description

[0025] Appendix Figure 1 A flowchart of the method for preparing wastewater treatment elements according to this application;

[0026] Appendix Figure 2 This is a model diagram of the wastewater treatment element in this application.

[0027] Figure labels: 1. Surface-adhered bacteria; 2. Bacteria inside the bubble; 3. Bubble. Detailed Implementation

[0028] To further illustrate the technical means and effects adopted by this application in order to achieve the intended purpose of the invention, the following detailed description of the specific implementation methods, structures, features and effects of this application is provided in conjunction with the accompanying drawings and preferred embodiments.

[0029] Example 1

[0030] S1. Preparation of basic hydrogel ink: 43% hydroxyethyl acryloyl, 4% polyethylene glycol dimethacrylate, 0.65% polyethylene glycol, 0.25% riboflavin and 52.1% water by mass fraction were mixed and magnetically stirred at 100 r / min for 1 hour at room temperature. Then the mixture was filtered through a 0.22 μm membrane filter to obtain the basic hydrogel ink for later use.

[0031] S2. Preparation of microbial glucose solution: Active microorganisms from a Shenzhen biotechnology company were selected from the market. 100g of active microorganisms were dissolved in 300g of water and magnetically stirred for 0.5 hours at 100r / min at room temperature. Then, the solution was filtered through a 0.45μm membrane filter to remove small particles. The microorganisms on the membrane filter were added to the glucose solution and allowed to stand. The mass ratio of microorganisms to glucose solution was controlled at 1:15. The solution was magnetically stirred for 0.5 hours at 100r / min at room temperature to obtain the microbial glucose solution. The solution was allowed to stand for 48 hours for later use.

[0032] S3. Preparation of bio-ink: The basic hydrogel ink prepared in S1 was mixed with the microbial glucose solution prepared in S2 and magnetically stirred for 0.5 hours at a speed of 100 r / min to obtain a clear, transparent, slightly yellow homogeneous liquid. Then, it was placed in a sealed space, filled with excess oxygen, and mechanically shaken. Since it is difficult to quantitatively measure the number and diameter of bubbles generated by filling with excess oxygen and mechanical shaking, according to the experience of the technicians, when air is added and shaken thoroughly, the result is turbid and opaque, which is considered to be the bio-ink containing more microbubbles and is the desired bio-ink.

[0033] S4. Preparation of wastewater treatment elements: Wastewater treatment elements were obtained using 3D printing technology. The 3D printing conditions were as follows: blue light with a wavelength of 400nm and an intensity of 50mw was selected. Blue light has no inactivating effect on microorganisms. Blue light has a much higher energy density than infrared light in the visible light spectrum, which provides energy for polymerization. Blue light has weak diffraction, which allows it to be focused in a smaller range, creating conditions for printing complex spatial structures.

[0034] Example 2

[0035] S1. Preparation of basic hydrogel ink: 40% hydroxyethyl acryloyl, 5% polyethylene glycol dimethacrylate, 0.5% polyethylene glycol, 0.3% riboflavin and 54.2% water by mass fraction were mixed and magnetically stirred for 1 hour at room temperature at a speed of 100 r / min. Then the mixture was filtered through a 0.22 μm membrane filter to obtain the basic hydrogel ink for later use.

[0036] S2. Preparation of microbial glucose solution: Active microorganisms from a Shenzhen biotechnology company were selected from the market. 100g of active microorganisms were dissolved in 300g of water and magnetically stirred for 0.5 hours at 100r / min at room temperature. Then, the solution was filtered through a 0.45μm membrane filter to remove small particles. The microorganisms on the membrane filter were added to the glucose solution and allowed to stand. The mass ratio of microorganisms to glucose solution was controlled at 1:15. The solution was magnetically stirred for 0.5 hours at 100r / min at room temperature to obtain the microbial glucose solution. The solution was allowed to stand for 48 hours for later use.

[0037] S3. Preparation of bio-ink: The basic hydrogel ink prepared in S1 was mixed with the microbial glucose solution prepared in S2 and magnetically stirred for 0.5 hours at a speed of 100 r / min to obtain a clear, transparent, slightly yellow homogeneous liquid. Then, it was placed in a sealed space, filled with excess oxygen, and mechanically shaken. Since it is difficult to quantitatively measure the number and diameter of bubbles generated by filling with excess oxygen and mechanical shaking, according to the experience of the technicians, when air is added and shaken thoroughly, the result is turbid and opaque, which is considered to be the bio-ink containing more microbubbles and is the desired bio-ink.

[0038] S4. Preparation of wastewater treatment elements: Wastewater treatment elements were obtained using 3D printing technology. The 3D printing conditions were as follows: blue light with a wavelength of 400nm and an intensity of 50mw was selected. Blue light has no inactivating effect on microorganisms. Blue light has a much higher energy density than infrared light in the visible light spectrum, which provides energy for polymerization. Blue light has weak diffraction, which allows it to be focused in a smaller range, creating conditions for printing complex spatial structures.

[0039] Example 3

[0040] S1. Preparation of basic hydrogel ink: 45% hydroxyethyl acryloyl, 3% polyethylene glycol dimethacrylate, 0.8% polyethylene glycol, 0.2% riboflavin and 51% water by mass fraction were mixed and magnetically stirred for 1 hour at room temperature at a speed of 100 r / min. Then the mixture was filtered through a membrane filter with a pore size of 0.22 μm to obtain the basic hydrogel ink for later use.

[0041] S2. Preparation of microbial glucose solution: Active microorganisms from a Shenzhen biotechnology company were selected from the market. 100g of active microorganisms were dissolved in 300g of water and magnetically stirred for 0.5 hours at 100r / min at room temperature. Then, the solution was filtered through a 0.45μm membrane filter to remove small particles. The microorganisms on the membrane filter were added to the glucose solution and allowed to stand. The mass ratio of microorganisms to glucose solution was controlled at 1:15. The solution was magnetically stirred for 0.5 hours at 100r / min at room temperature to obtain the microbial glucose solution. The solution was allowed to stand for 48 hours for later use.

[0042] S3. Preparation of bio-ink: The basic hydrogel ink prepared in S1 was mixed with the microbial glucose solution prepared in S2 and magnetically stirred for 0.5 hours at a speed of 100 r / min to obtain a clear, transparent, slightly yellow homogeneous liquid. Then, it was placed in a sealed space, filled with excess oxygen, and mechanically shaken. Since it is difficult to quantitatively measure the number and diameter of bubbles generated by filling with excess oxygen and mechanical shaking, according to the experience of the technicians, when air is added and shaken thoroughly, the result is turbid and opaque, which is considered to be the bio-ink containing more microbubbles and is the desired bio-ink.

[0043] S4. Preparation of wastewater treatment elements: Wastewater treatment elements were obtained using 3D printing technology. The 3D printing conditions were as follows: blue light with a wavelength of 400nm and an intensity of 50mw was selected. Blue light has no inactivating effect on microorganisms. Blue light has a much higher energy density than infrared light in the visible light spectrum, which provides energy for polymerization. Blue light has weak diffraction, which allows it to be focused in a smaller range, creating conditions for printing complex spatial structures.

[0044] Comparative Example 1

[0045] The main difference between this comparative example and Example 1 is that this comparative example does not provide a nutrient solution of glucose.

[0046] Comparative Example 2

[0047] The main difference between this comparative example and Example 1 is that the microorganisms in this comparative example were not activated in glucose solution for 48 hours.

[0048] Comparative Example 3

[0049] The main difference between this comparative example and Example 1 is that the printing ink in this comparative example was printed directly without oxygen filling.

[0050] Comparative Example 4

[0051] The wastewater treatment unit used in this comparative example was purchased from Bayer.

[0052] Performance testing

[0053] The wastewater treatment units prepared in Examples 1-3, Comparative Examples 1-3, and the purchased wastewater treatment unit in Comparative Example 4 were used in a simulated experiment in an MBBR bioreactor (wastewater treatment equipment). The wastewater treatment units prepared in Examples 1-3 and Comparative Examples 1-3 had a filling rate of 15%, while the wastewater treatment unit purchased in Comparative Example 4 had a filling rate of 30%. The water used was domestic sewage from a substation, with 1000L collected at a time for a small-scale dynamic test. Its COD was 386 mg / L, the operating oxygen content was 2 mg / L, the retention time was 5 hours, and the total amount of wastewater in the reactor was approximately 10L. The effluent COD was calculated, and the results are shown in Table 1.

[0054] Table 1

[0055]

[0056] Because the COD of the effluent in the early stage of Comparative Example 4 was relatively high, the statistical period was relatively long. The specific results are as follows: COD of effluent > 200 mg / L in the first 3 days; COD of effluent > 120 mg / L in days 4 to 7; COD of effluent = 50 to 120 mg / L in days 7 to 20; COD of effluent = 40 to 50 mg / L in days 20 to 30.

[0057] Results Analysis

[0058] Based on Examples 1-3, Comparative Examples 1-4, and Table 1, it can be seen that the wastewater treatment element prepared using the method of this application achieved an effluent COD of 13-35 mg / L on day 4 in the simulation experiment, meeting the Class III surface water standard. However, Comparative Example 1, lacking nutrient provision, required microorganisms to obtain nutrients from wastewater, which was unstable, affecting microbial growth and reproduction, thus impacting wastewater treatment effectiveness. Comparative Example 2, without microbial activation, required activation and growth in water, preventing immediate entry into wastewater treatment, directly resulting in poor initial treatment performance. Comparative Example 3, lacking excessive oxygen in the ink, resulted in a dense structure of the 3D-printed wastewater element, limiting the space for microbial growth and reproduction, thus leading to poor wastewater treatment performance. Comparative Example 4 achieved an effluent COD of 40-50 mg / L after 20-30 days.

[0059] The above description is merely a preferred embodiment of this application and is not intended to limit this application in any way. Although this application has been disclosed above with reference to preferred embodiments, it is not intended to limit this application. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the technical solution of this application. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of this application without departing from the scope of the technical solution of this application shall still fall within the scope of the technical solution of this application.

Claims

1. A method for preparing wastewater treatment elements based on 3D printing, characterized in that, Includes the following steps: S1. Preparation of basic hydrogel ink: Mix 40%~45% unsaturated monomer, 3%~5% crosslinking agent, 0.5%~0.8% aqueous photoluminescent agent and 0.2%~0.3% light absorber with the balance of water, and filter through a membrane filter to obtain basic hydrogel ink for later use; S2. Preparation of microbial glucose solution: Dissolve microorganisms in water, then filter through a membrane filter, and add the microorganisms on the membrane filter to the glucose solution and let it stand to obtain microbial glucose solution for later use; S3. Preparation of bio-ink: The basic hydrogel ink prepared in S1 is mixed with the microbial glucose solution prepared in S2, placed in a closed space, filled with oxygen, and mechanically shaken to obtain bio-ink; S4. Preparation of wastewater treatment elements: The bio-ink prepared in S3 was used to obtain wastewater treatment elements using 3D printing technology; The aqueous photoluminescent agent described in S1 is polyethylene glycol; The light absorber in S1 is riboflavin; the pore size of the membrane filter is 0.22 μm. The filter membrane in S2 has a pore size of 0.45 μm, the glucose solution has a mass fraction of 2%, the mass ratio of the microorganisms to the glucose solution is 1:15, and the settling time is 48 h. The mass ratio of the basic hydrogel ink to the microbial glucose solution in S3 is 30:

1. When the bio-ink obtained by filling with oxygen and mechanically shaking becomes turbid and opaque, it is the desired bio-ink. The 3D printing conditions described in S4 are blue light with a wavelength of 400nm and an intensity of 50mw.

2. The method for preparing wastewater treatment elements based on 3D printing according to claim 1, characterized in that, The unsaturated monomer in S1 is hydroxyethylacrylamide.

3. The method for preparing wastewater treatment elements based on 3D printing according to claim 1, characterized in that, The crosslinking agent mentioned in S1 is polyethylene glycol dimethacrylate.

4. The application of the wastewater treatment unit obtained by the 3D printing-based wastewater treatment element preparation method according to any one of claims 1 to 3, characterized in that, Used for wastewater treatment.

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