A method for preparing activated sludge bioimmobilization gel balls based on retired wind turbine blade materials

Abstract

The present invention discloses a method for preparing activated sludge bio-immobilized gel balls based on retired wind turbine blade materials, which belongs to the field of environmental engineering technology. The gel balls can effectively fix activated sludge and have the advantages of high mechanical strength, non-toxicity, good biocompatibility, etc. The gel-embedded particles modified with polypropylene oxide have high thermal stability and large total pore volume, can effectively embed activated sludge, reduce the harm to microorganisms, and are suitable for online toxicity warning devices in sewage treatment plants, improve the accuracy and stability of warnings, and ensure the stable operation of sewage treatment plants. At the same time, the present invention provides a new direction for the green recycling of retired wind turbine blades, converting blade materials into bio-immobilized gel balls with environmental benefits and application value, realizing the value enhancement and function expansion of blade recycling.

Description

Technical Field

[0001] The invention relates to a method for preparing activated sludge bio-immobilization gel balls based on retired wind turbine blade materials, belonging to the technical field of environmental engineering. Background Art

[0002] The increasing problem of sewage, particularly the complex composition of industrial wastewater, poses a significant challenge to municipal wastewater treatment plants. After initial treatment, these wastewaters enter the municipal system and may contain substances that inhibit biochemical treatment, threatening the stability of effluent quality. Currently, my country relies on the activated sludge process and its improved technologies to treat municipal sewage. However, these technologies suffer from reduced treatment efficiency when dealing with toxic industrial wastewater, increasing economic costs and emission risks. To address this issue, biological toxicity early warning technologies, particularly those based on respiratory rate (OUR) monitoring, have become an important research focus in wastewater treatment. However, due to the unstable activated sludge microbial biomass, the accuracy of existing toxicity warning systems decreases over time. Therefore, a method for long-term preservation of activated sludge microbial biomass is needed to ensure the long-term effectiveness of toxicity warning systems. One solution is to prepare gel spheres to immobilize activated sludge and reduce its loss.

[0003] In addition, with the growing global demand for renewable energy, wind power generation has been widely used as a clean and renewable form of energy. However, after a certain number of years of use, the blades of wind turbines will be retired due to aging, wear and tear, etc. These retired wind turbine blades are usually made of composite materials such as glass fiber reinforced plastic, which are difficult to degrade and put great pressure on the environment. Therefore, new processes can be explored to recycle retired wind turbine blades to prepare gel balls suitable for toxicity warning systems, which can solve both the recycling problem of retired wind turbine blades and the problem of toxicity warning systems.

[0004] Currently, existing technologies for toxicity warning systems include patent CN 117904093 A (A Method for Preparing Low-Cost, High-Efficiency Activated Sludge Bio-Encapsulated Gel Spheres), which discloses a technique for encapsulating activated sludge using a polyvinyl alcohol-guar gum gel modified with the silane coupling agent KH550. However, its thermal stability and mechanical strength are less than ideal, and it does not address the recycling of retired wind turbine blades. Regarding retired wind turbine blades, the review "Current Status and Prospects of Wind Blade Recycling Technology" describes several methods, including mechanical, pyrolytic, and chemical recycling, but does not mention their application in gel spheres. Summary of the Invention

[0005] To achieve the above objectives, the present invention aims to provide a method for preparing activated sludge bio-immobilized gel balls based on retired wind turbine blade materials, that is, to prepare an innovative green resource-based activated sludge embedded particle, which can effectively achieve the immobilization of activated sludge and enhance the mechanical strength of the gel ball. Such particles are used in the toxicity warning system of sewage treatment plants to improve the accuracy and reliability of toxicity warnings and ensure the stability of sewage treatment plant operations. The method of the present invention not only provides a new idea for the recycling of retired blades, but also ensures the stability of the toxicity monitoring system through efficient embedding and immobilization technology.

[0006] The present invention provides a method for preparing activated sludge gel balls based on retired wind turbine blade materials, comprising the following steps:

[0007] (1) disassembling retired fan blades, cleaning and drying them, and then crushing and sieving the disassembled retired fan blades to obtain fan blade material powder;

[0008] (2) Inoculating aerobic activated sludge in an SBR reactor, introducing sewage into the reactor to acclimate the nitrified sludge to obtain acclimatized nitrified sludge, then centrifuging the acclimatized nitrified sludge to retain the precipitate, and washing the precipitate to obtain activated sludge;

[0009] (3) Mixing activated sludge, polypropylene oxide, and polyvinyl alcohol solution, and then adding fan blade material powder to obtain a mixed solution;

[0010] (4) The mixed solution was added dropwise to a saturated boric acid solution of calcium chloride to form spherical particles, and the spherical particles were taken out and transferred to a Na2SO4 aqueous solution for cross-linking and solidification to obtain gel balls, and the gel balls were taken out, washed, and subjected to freeze-thaw cycles;

[0011] (5) The gel balls after freeze-thaw cycles are cultured in a batch culture method to restore the activity of the activated sludge embedded gel balls, and finally the activated sludge gel balls are obtained.

[0012] Furthermore, the retired wind turbine blades in step (1) refer to wind turbine blades that have reached their service life or are no longer usable due to damage.

[0013] Furthermore, the mesh size of the sieving in step (1) is 300 to 500 meshes.

[0014] Furthermore, the particle size of the fan blade material powder in step (1) is less than 25 microns.

[0015] Furthermore, the aerobic activated sludge in step (2) is taken from the activated sludge in the aerobic tank of the AAO process section of the sewage treatment plant.

[0016] Furthermore, the components of the wastewater in step (2) include 300-350 mg / L COD, 4-5 mg / L TP, trace elements and 25-45 mg / L NH4 + -N.

[0017] Furthermore, the composition of trace elements includes 2-3 mg / LCaCl2.2H2O, 2-3 mg / LMgSO4.7H2O,

[0018] 0.6~1mg / LFeCl2.4H2O, 0.6~1mg / LCoCl2.6H2O, 0.15~0.2mg / LMnCl2.4H2O,

[0019] 0.009~0.01mg / LCuCl2.2H2O, 0.015~0.02mg / LZnCl2, 0.015~0.02mg / LHBO3,

[0020] 0.027~0.03mg / L(NH4)6Mo7O 24 .4H2O, 0.015~0.02mg / LNiCl2.6H2O, 0.3~0.5mg / LEDTA (tripex 2).

[0021] Furthermore, the pH during the acclimation process in step (2) is 7.5 to 8.5.

[0022] Furthermore, aeration is required during the acclimation process in step (2); aeration is continued for 5 to 6 hours, and then the mixture is allowed to stand for 0.5 to 1 hour, the supernatant is removed, and sewage is added to continue acclimation, and aeration is performed again after an interval of 15 to 20 hours.

[0023] Furthermore, the acclimation time in step (2) is 10 to 15 days.

[0024] Furthermore, the average degree of polymerization of polyvinyl alcohol in the polyvinyl alcohol solution in step (3) is 1750±50.

[0025] Furthermore, the concentration of polyvinyl alcohol in the polyvinyl alcohol solution in step (3) is 85 to 95 wt%.

[0026] Furthermore, in step (3), the volume ratio of activated sludge to polypropylene oxide is 10:0.3-0.5.

[0027] Furthermore, in step (3), the volume ratio of activated sludge to polyvinyl alcohol solution is 10:85-90.

[0028] Furthermore, in step (3), the mass concentration of the fan blade material powder in the mixed liquid is 4 to 6 wt%.

[0029] Furthermore, the concentration of calcium chloride in the saturated boric acid solution of calcium chloride in step (4) is 1 to 3 wt%.

[0030] Furthermore, the concentration of Na2SO4 in the Na2SO4 aqueous solution in step (4) is 0.5 to 1 mol / L.

[0031] Furthermore, in step (4), the cross-linking and curing temperature is 0 to 5° C., and the cross-linking and curing time is 30 to 50 minutes.

[0032] Furthermore, the freeze-thaw cycle in step (4) is to first freeze for 6 to 10 hours, then take out and thaw for 2 to 5 hours, and the number of cycles is 2 to 5 times; the freezing temperature is -30 to -10°C.

[0033] Furthermore, the components of the wastewater used in the batch culture method in step (5) include 300-350 mg / LCOD, 4-5 mg / L TP, trace elements and 25-45 mg / L NH4 + -N.

[0034] Furthermore, the composition of trace elements includes 2-3 mg / LCaCl2.2H2O, 2-3 mg / LMgSO4.7H2O,

[0035] 0.6~1mg / LFeCl2.4H2O, 0.6~1mg / LCoCl2.6H2O, 0.15~0.2mg / LMnCl2.4H2O,

[0036] 0.009~0.01mg / LCuCl2.2H2O, 0.015~0.02mg / LZnCl2, 0.015~0.02mg / LHBO3,

[0037] 0.027~0.03mg / L(NH4)6Mo7O 24 .4H2O, 0.015~0.02mg / LNiCl2.6H2O, 0.3~0.5mg / LEDTA (tripex 2).

[0038] Furthermore, in step (5), the batch culture method is cultured for 8 to 10 cycles, each cycle lasting 8 to 10 hours; one cycle specifically comprises: water inlet for 10 to 15 minutes, reaction for 6 to 8 hours, precipitation for 1.5 to 2 hours, and drainage for 10 to 15 minutes.

[0039] The present invention provides activated sludge gel balls prepared according to the method.

[0040] The activated sludge gel balls provided by the present invention are used in the environmental field.

[0041] Beneficial effects of the present invention:

[0042] (1) In the present invention, the fan blades are crushed, combined with polyvinyl alcohol, and modified with polypropylene oxide to prepare a microorganism-embedded gel ball. Compared with other blade recycling methods, this method has the advantages of good material compatibility and strong functionality. The good biocompatibility and film-forming properties of polyvinyl alcohol make it compatible with the crushed fan blade material, and can prepare gel balls with excellent stability; polypropylene oxide can also improve the mechanical strength of the gel balls, reduce the breakage of the gel balls and the loss of activated sludge, and make the gel balls have a larger total pore volume and a better pore structure. The gel balls can be used in environmental remediation, biodegradation, toxicity warning devices and other fields, thereby realizing the value enhancement and functional expansion of blade recycling.

[0043] (2) The gel spheres prepared by the present invention have the following characteristics: excellent thermal stability, with the mass of gel particles being only 1.1166%; significantly improved mechanical strength; and a larger total pore volume, with the total pore volume reaching 0.016 cm 3 / g; non-toxic and with good biocompatibility. Therefore, the gel ball can effectively embed activated sludge and is suitable for toxicity warning devices, ensuring their operational stability and accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 This is the morphology of gel particles after being embedded in retired wind turbine blade materials.

[0045] Figure 2 This is a diagram showing the changes in nitration performance during the activity recovery process of embedded gel particles. DETAILED DESCRIPTION

[0046] The following describes preferred embodiments of the present invention. It should be understood that the embodiments are for better explanation of the present invention and are not intended to limit the present invention.

[0047] Source of raw materials

[0048] The embedded activated sludge was taken from the aerobic tank activated sludge of the AAO process section of a municipal sewage treatment plant in Wuxi City; PVA and PPG were purchased from Sinopharm Chemical Reagent Co., Ltd.; the retired fan blades were taken from the blades of a wind turbine generator set, and the original manufacturer was Sinoma Technology Co., Ltd. The blades are mainly a hybrid composite structure of glass fiber (GF) and carbon fiber (CF).

[0049] Preparation of retired fan blade material powder: disassemble the retired fan blades, clean and dry them to remove dirt and dust, then use a grinder to crush the retired fan blade parts, pass them through a 500-mesh sieve, and retain particles with a particle size of less than 25 microns to obtain retired fan blade material powder.

[0050] Example 1: Cultivation of activated sludge with high nitrification performance

[0051] The activated sludge from the aerobic tank was used as the starting sludge and cultured and acclimated in the SBR system (volume 2L). During the acclimation period, the influent COD was set to 300mg / L, TP to 4mg / L, and NH4 was adjusted at a frequency of every 5 days. + -N concentration is 25, 35, and 45 mg / L, respectively, to adjust the carbon-nitrogen ratio and promote the growth of nitrifying bacteria. In addition, trace elements are supplemented, as shown in Table 1, and the addition amount is 0.5 mL / L, to facilitate the reproduction of microorganisms in activated sludge. During the process, Na2CO3 is added in a timely manner to maintain the pH of the wastewater between 7.5 and 8.5, which is suitable for the survival of nitrifying bacteria. Aeration for 5.5 hours and sedimentation for 30 minutes are required every day, and then the supernatant is discharged and freshly prepared sewage is added to continue acclimation. After that, the aeration, sedimentation, drainage and water replenishment operations are repeated after an interval of 19 hours. After 15 days, the acclimated nitrified sludge is obtained.

[0052] Table 1 Trace element preparation

[0053]

[0054]

[0055] Example 2: Using fan blade material to embed sludge to construct gel balls

[0056] Polyvinyl alcohol (average degree of polymerization: 1750±50) and deionized water were mixed in a mass ratio of 1:9, heated on an induction cooker for 2-3 hours with constant stirring to ensure complete dissolution of the polyvinyl alcohol particles, and then cooled to room temperature to obtain a polyvinyl alcohol solution. The acclimated nitrified sludge was centrifuged to obtain a precipitate, which was then washed 2-3 times with brine to obtain the nitrified sludge. The nitrified sludge, polypropylene oxide (PPG), and polyvinyl alcohol solution were then mixed in a volume ratio of 10:0.3:89.7, and fan blade material powder was added and stirred to obtain a mixed solution. The fan blade material powder accounted for 5wt% of the total mass of the mixed solution. The mixed solution was then added dropwise to a saturated boric acid solution containing 2wt% calcium chloride to form spherical particles. The spherical particles were then transferred to a 0.5mol / L aqueous solution of Na2SO4 and cross-linked and cured in a refrigerator at 5°C for 35 minutes to obtain gel spheres. The gel spheres were then removed and washed with a 0.9wt% NaCl solution to remove any residual boric acid. The gel spheres were then subjected to three freeze-thaw cycles in a -20°C freezer to enhance their mechanical strength. Each freeze-thaw cycle consisted of freezing for 8 hours and then thawing for 4 hours. Finally, the frozen-thawed gel spheres were rinsed with deionized water, immersed in simulated domestic sewage, and stored at 4°C until use.

[0057] The total pore volume and average pore size of the modified gel balls increased, which can better fix the activated sludge and reduce the loss of microorganisms. The morphology of the gel balls after embedding in the retired fan blades is shown in the figure. Figure 1 .

[0058] Example 3: Restoration of activity of activated sludge-embedded gel spheres by sequencing batch culture

[0059] On the basis of Example 2, in order to compensate for the damage to microbial activity that may have occurred during the preparation process and to ensure the performance of the gel balls in subsequent applications, the activity recovery experiment of the gel balls finally prepared in Example 2 was carried out using simulated wastewater. The simulated wastewater composition included 300 mg / L COD, 4 mg / L TP, trace elements (see Table 1), and 25 mg / L NH4 + -N, the recovery was carried out in 8 cycles (10 hours per cycle) by sequencing batch culture to effectively activate the microorganisms in the gel balls, specifically: 15 minutes of water inlet, 8 hours of reaction, 1.5 hours of precipitation, and 15 minutes of drainage, with no interval between adjacent cycles. The changes in nitrification performance during the recovery of the activity of the embedded particles are shown in Figure 2 .

[0060] Comparative Example 1: Comparison of different treatment methods for retired blades

[0061] As a clean energy source, wind power generation plays an important role in promoting global energy transformation. However, the recycling of retired wind turbine blades has always been a challenge faced by the industry. Traditional physical and chemical recycling methods have problems such as low recovery rate, high cost, and pollution, which limit their development. This study proposes an innovative solution, which is to use retired wind turbine blade materials to prepare activated sludge bio-immobilized gel balls. This solution not only effectively solves the environmental pollution problem of retired blades and realizes resource recycling, but also improves the added value and application scope of the product through efficient encapsulation and immobilization technology, and has significant economic, environmental and social benefits. Table 2 is a comparison of several treatment methods for retired wind turbine blades.

[0062] Table 2 Comparison of treatment methods for retired wind turbine blades

[0063]

[0064] Comparative Example 2: Comparison of main materials for activated sludge embedded gel particles

[0065] The main material of the present invention is polyvinyl alcohol, which is a commonly used hydrogel preparation material. Combining polyvinyl alcohol with retired wind turbine blade materials to prepare activated sludge embedded gel balls can achieve complementary advantages and improve the performance of the gel balls. Retired wind turbine blade materials are mainly made of composite materials such as glass fiber reinforced plastics, which have advantages such as high strength and corrosion resistance, but they are difficult to degrade and put pressure on the environment. After the blade material is crushed and mixed with polyvinyl alcohol, a composite material with good biocompatibility can be prepared, and the gel balls can be given higher mechanical strength and corrosion resistance. In addition, the glass fiber and other components rich in the blade material can also enhance the pore structure of the gel balls and improve their immobilization efficiency for activated sludge. In contrast, other commonly used gel materials, such as agar and calcium alginate, although they also have certain biocompatibility, have poor mechanical strength and are difficult to withstand external forces such as aeration and scouring. They are easily broken and lead to the loss of activated sludge. Therefore, combining polyvinyl alcohol with retired wind turbine blade materials to prepare activated sludge embedded gel balls is an innovative solution that has both environmental and practical value. Table 3 is a comparison of the properties of the candidate materials. It can be seen that choosing polyvinyl alcohol as the main material to prepare sludge-embedded gel particles is a better choice.

[0066] Table 3 Performance comparison of several embedding materials

[0067]

[0068] Comparative Example 3: Comparison of Modifiers for Embedded Gel Balls in Activated Sludge

[0069] The physical and chemical properties of unmodified gel spheres, such as thermal stability, pore morphology, functional groups, and ammonia-oxygen mass transfer performance, are relatively inferior to those of modified gel spheres. However, the modified gel spheres exhibit enhanced mechanical strength and a smaller average pore size, enabling better sludge encapsulation. Polypropylene oxide (PPG), a commonly used biomedical material, can effectively enhance the performance of activated sludge-encapsulated gel spheres prepared with polyvinyl alcohol (PVA). The introduction of PPG enhances the thermal stability of the gel spheres, making them less susceptible to deformation or decomposition in high-temperature environments, thereby ensuring their long-term use. Furthermore, PPG significantly improves the mechanical strength of the gel spheres, making them more durable and able to withstand external forces such as aeration and scouring, thereby reducing breakage and activated sludge loss. Furthermore, the PPG-modified gel spheres possess a larger total pore volume and a more optimized pore structure, facilitating the transfer of nutrients and metabolic waste, providing a more favorable environment for microbial growth and metabolism. Furthermore, PPG exhibits excellent biocompatibility and is non-toxic to microorganisms, ensuring the normal function of activated sludge. Table 4 is a comparison of the performance of the selected modifiers.

[0070] Table 4 Comparison of modifier performance

[0071]

[0072] Comparative Example 4

[0073] The gel balls were prepared and activated according to the steps of Examples 2 and 3, except that only the fan blade material powder was omitted.

[0074] The gel spheres prepared in Example 3 and Comparative Example 4 were tested. The testing contents included: thermogravimetric analysis using a TGA5500 thermogravimetric analyzer (TA, USA) at a temperature of 30-500°C and a heating rate of 10°C / min; BET using a Belsorp-Max fully automatic specific surface area and pore distribution analyzer (MicrotracBEL, Japan).

[0075] The test results show that the gel spheres prepared in Example 3 exhibit minimal mass loss of 1.1166% at room temperature (30-50°C), indicating good thermal stability at room temperature, capable of maintaining the biomass of activated sludge and ensuring continuous and stable operation in the toxicity warning device. However, the gel spheres prepared in Comparative Example 4 exhibited significant mass loss of 4.2674% at room temperature (30-50°C), failing to ensure stable operation in the toxicity warning device.

[0076] The specific surface area and pore size of the gel spheres prepared in Example 3 and Comparative Example 4 are compared in Table 5. The gel spheres prepared in Example 3 have greater advantages in terms of specific surface area, total pore volume and average pore size.

[0077] Table 5 Comparison of gel balls in Example 3 and Comparative Example 4

[0078]

[0079]

[0080] Comparative Example 5

[0081] The gel spheres were prepared and activated by referring to the steps of Examples 2 and 3, except that the volume ratio of nitrified sludge, polypropylene oxide and polyvinyl alcohol solution was adjusted to 10:1:89.

[0082] After preparation, the pore structure of the gel balls was tested using a Belsorp-Max fully automatic specific surface area and pore distribution analyzer (MicrotracBEL, Japan). The AUR detection method was to place the gel balls in an iodine volumetric flask, add appropriate amounts of NH4Cl and NaHCO3 to the iodine volumetric flask to make the ammonia nitrogen concentration reach 25 mg / L, aerate and maintain the DO at approximately 2 mg / L, and continuously stir to ensure that the solution and activated sludge are evenly mixed. The ammonia nitrogen concentration of the mixed solution in the iodine volumetric flask at different time points was measured and combined with the concentration of activated sludge in the mixed solution to calculate the ammonia oxidation rate.

[0083] Table 5 is a comparison of the specific surface area and pore structure of the gel spheres prepared in Example 3 and Comparative Example 5. From Table 6, it can be found that the gel spheres prepared in Example 3 have more advantages in terms of specific surface area, total pore volume and average pore diameter.

[0084] Table 6 Comparison of gel balls in Example 3 and Comparative Example 5

[0085]

[0086] Depend on Figure 2 As shown, the AUR of the gel spheres prepared in Example 3 is 2.4NH4 + -N / (g VSS·h), while the gel sphere AUR prepared in Comparative Example 5 only had 1.9NH4 + -N / (g VSS·h), so excessive use of polypropylene oxide will harm the embedded sludge. In comparison, the gel balls prepared in Example 3 have more advantages.

[0087] Comparative Example 6

[0088] The gel balls were prepared and activated by referring to the steps of Examples 2 and 3, wherein only the amount of fan blade material powder added was adjusted to 3%.

[0089] The test contents include: thermogravimetric analysis using a TGA5500 thermogravimetric analyzer (TA, USA) at a temperature of 30-500°C and a heating rate of 10°C / min; BET testing using a Belsorp-Max fully automatic specific surface area and pore distribution analyzer (MicrotracBEL, Japan); and calculation of ammonia and oxygen mass transfer characteristics using the formula:

[0090]

[0091] Where: D e is the effective diffusion coefficient, m 2 / s;C b is the instantaneous concentration of the matrix in the bulk solution, mg / L; C b0 is the initial concentration of the matrix in the main solution, which is 50 mg / L; a is the ratio of liquid volume to particle volume, which is 4; q1 is a non-zero positive root; R is the particle radius, which is 3.4×10 -3 m.

[0092] turn out:

[0093] (1) The gel spheres prepared in Example 3 exhibited minimal mass loss of 1.1166% at room temperature (30-50°C), indicating good thermal stability at room temperature and the ability to operate stably in the toxicity warning device. In contrast, the gel spheres prepared in Comparative Example 6 exhibited a significant mass loss of 3.7886% at room temperature (30-50°C).

[0094] (2) The specific surface area and pore size of the gel spheres prepared in Example 3 and Comparative Example 6 are compared in Table 7. The gel spheres prepared in Example 3 have more advantages in terms of specific surface area, total pore volume and average pore size.

[0095] Table 7 Comparison of gel balls in Example 3 and Comparative Example 6

[0096]

[0097] (3) The ammonia diffusion coefficients De of the gel balls prepared in Example 3 and Comparative Example 6 were calculated to be 4.5673×10 - 10 m 2 / s、4.4626×10 -10 m 2 / s; the oxygen diffusion coefficient De is 2.1673×10 -10 m 2 / s, 2.0626×10 -10 m 2 / s; It can be seen that the gel balls prepared in Example 3 have more advantages.

[0098] Comparative Example 7

[0099] The gel balls were prepared and activated by referring to the steps of Examples 2 and 3, wherein only the addition amount of the fan blade material powder was adjusted to 8%, and the test contents were the same as those of Comparative Example 6.

[0100] turn out:

[0101] (1) The gel spheres prepared in Example 3 exhibited minimal mass loss of 1.1166% at room temperature (30-50°C), indicating good thermal stability at room temperature and the ability to operate stably in the toxicity warning device. In contrast, the gel spheres prepared in Comparative Example 6 exhibited a relatively large mass loss of 2.3562% at room temperature (30-50°C).

[0102] (2) The specific surface area and pore size of the gel spheres prepared in Example 3 and Comparative Example 7 are compared in Table 8. The gel spheres prepared in Example 3 have more advantages in terms of specific surface area, total pore volume and average pore size.

[0103] Table 8 Comparison of gel balls in Example 3 and Comparative Example 7

[0104]

[0105] (3) The ammonia diffusion coefficients De of the gel balls prepared in Example 3 and Comparative Example 6 were calculated to be 4.5673×10 - 10 m 2 / s, 4.1421×10 -10 m 2 / s; the oxygen diffusion coefficient De is 2.1673×10 -10 m 2 / s, 1.9873×10 -10 m 2 / s; It can be seen that the gel balls prepared in Example 3 have more advantages.

[0106] The embodiments provided above are not intended to limit the scope of the present invention, nor are the steps described to limit their execution order. Any obvious improvements to the present invention made by those skilled in the art in combination with existing common knowledge shall fall within the scope of protection defined by the claims of the present invention.

Claims

1. A method for preparing activated sludge gel balls based on retired wind turbine blade materials, characterized in that: The following steps are involved: (1) disassembling retired fan blades, cleaning and drying them, and then crushing and sieving the disassembled retired fan blades to obtain fan blade material powder; (2) Inoculating aerobic activated sludge in an SBR reactor, introducing sewage into the reactor to acclimate the nitrified sludge to obtain acclimatized nitrified sludge, then centrifuging the acclimatized nitrified sludge to retain the precipitate, and washing the precipitate to obtain activated sludge; (3) Mixing activated sludge, polypropylene oxide, and polyvinyl alcohol solution, and then adding fan blade material powder to obtain a mixed solution; the concentration of polyvinyl alcohol in the polyvinyl alcohol solution is 85-95 wt%; the volume ratio of activated sludge to polypropylene oxide is 10:0.3-0.5; the volume ratio of activated sludge to polyvinyl alcohol solution is 10:85-90; the mass concentration of fan blade material powder in the mixed solution in step (3) is 4-6 wt%; (4) The mixed solution was added dropwise to a saturated boric acid solution of calcium chloride to form spherical particles, and the spherical particles were taken out and transferred to a Na2SO4 aqueous solution for cross-linking and solidification to obtain gel balls, and the gel balls were taken out, washed, and subjected to freeze-thaw cycles; (5) The gel balls after freeze-thaw cycles are cultured in a batch culture method to restore the activity of the activated sludge embedded gel balls, and finally the activated sludge gel balls are obtained.

2. The method according to claim 1, wherein The components of the wastewater in step (2) include 300-350 mg / LCOD, 4-5 mg / L TP, trace elements and 25-45 mg / L NH4 + -N; trace elements include 2-3 mg / LCaCl2.2H2O, 2-3 mg / LMgSO4.7H2O, 0.6-1 mg / LFeCl2.4H2O, 0.6-1 mg / LCoCl2.6H2O, 0.15-0.2 mg / LMnCl2.4H2O, 0.009-0.01 mg / LCuCl2.2H2O, 0.015-0.02 mg / LZnCl2, 0.015-0.02 mg / LHBO3, 0.027-0.03 mg / L(NH4)6Mo7O 24 .4H2O, 0.015~0.02mg / LNiCl2.6H2O, 0.3~0.5mg / LEDTA (tripex 2).

3. The method according to claim 1, wherein Aeration is required during the acclimation process in step (2); aeration is continued for 5 to 6 hours, then allowed to stand for 0.5 to 1 hour, the supernatant is removed, and sewage is added to continue acclimation, and aeration is performed again after an interval of 15 to 20 hours; the acclimation time is 10 to 15 days.

4. The method according to claim 1, wherein The average degree of polymerization of polyvinyl alcohol in the polyvinyl alcohol solution in step (3) is 1750±50.

5. The method according to claim 1, wherein The concentration of calcium chloride in the saturated boric acid solution of calcium chloride in step (4) is 1-3 wt %; the concentration of Na 2 SO 4 in the Na 2 SO 4 aqueous solution is 0.5-1 mol / L.

6. The method according to claim 1, wherein The freeze-thaw cycle in step (4) is to first freeze for 6 to 10 hours, then take out and thaw for 2 to 5 hours, and the number of cycles is 2 to 5 times; the freezing temperature is -30 to -10°C.

7. The method according to claim 1, characterized in that The components of the wastewater used in the batch culture method in step (5) include 300-350 mg / L COD, 4-5 mg / L TP, trace elements and 25-45 mg / L NH4 + -N; trace elements include 2-3 mg / LCaCl2.2H2O, 2-3 mg / LMgSO4.7H2O, 0.6-1 mg / LFeCl2.4H2O, 0.6-1 mg / LCoCl2.6H2O, 0.15-0.2 mg / LMnCl2.4H2O, 0.009-0.01 mg / LCuCl2.2H2O, 0.015-0.02 mg / LZnCl2, 0.015-0.02 mg / LHBO3, 0.027-0.03 mg / L(NH4)6Mo7O 24 .4H2O, 0.015~0.02mg / LNiCl2.6H2O, 0.3~0.5mg / LEDTA (tripex 2).

8. The method according to claim 1, wherein In step (5), the batch culture method is cultured for 8 to 10 cycles, each cycle lasting 8 to 10 hours; one cycle specifically comprises: water inlet for 10 to 15 minutes, reaction for 6 to 8 hours, precipitation for 1.5 to 2 hours, and drainage for 10 to 15 minutes.

9. Activated sludge gel balls prepared according to the method according to any one of claims 1 to 8.

10. Use of the activated sludge gel balls according to claim 9 in the environmental field.

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