Method for preparing activated sludge biological immobilized gel balls based on retired wind turbine blade material

Abstract

The invention discloses a method for preparing activated sludge biological immobilized gel balls based on a retired wind turbine blade material, and belongs to the technical field of environmental engineering. The gel ball can effectively fix activated sludge, and has the advantages of high mechanical strength, no toxicity, good biocompatibility and the like. The polypropylene oxide modified gel embedded particles are high in thermal stability and large in total pore volume, can effectively embed activated sludge and reduce harm to microorganisms, are suitable for an on-line toxicity early warning device of a sewage treatment plant, improve early warning precision and stability and guarantee stable operation of the sewage treatment plant. Meanwhile, a new direction of green recycling is provided for the retired fan blades, blade materials are converted into biological immobilized gel balls with environmental protection benefits and application values, and value improvement and function expansion of blade recycling are achieved.

Description

Technical Field

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

[0002] The intensification of sewage problems, especially the complex components in industrial wastewater, poses a major challenge to municipal sewage treatment plants. These wastewaters are discharged into the municipal system after preliminary treatment and may contain substances that inhibit biochemical treatment, threatening the stability of effluent quality. At present, my country relies on the activated sludge method and its improved technology to treat urban sewage, but these technologies have reduced treatment efficiency when dealing with toxic industrial wastewater, increasing economic costs and emission risks. In response to this problem, biological toxicity early warning technology, especially monitoring technology based on respiratory rate (OUR), has become an important direction of wastewater treatment research. However, the existing toxicity warning system has a non-fixed activated sludge microbial biomass, and its warning accuracy will decrease over time. Therefore, a method that can preserve the activated sludge microbial biomass for a long time is needed to ensure the long-term and effective operation of the toxicity warning system. In this regard, preparing a gel ball to fix the activated sludge and reduce the loss of activated sludge is a solution.

[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 plastics, 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] At present, the existing technology for toxicity warning system includes patent CN 117904093 A (a method for preparing a low-cost, high-immobilization-efficiency activated sludge biological embedding gel ball), which discloses a technology for embedding and fixing activated sludge using polyvinyl alcohol-guar gum gel modified by silane coupling agent KH550, but its thermal stability and mechanical strength are not ideal, and it also does not involve the recycling of retired wind turbine blades. In terms of retired wind turbine blades, the review document "The Current Status and Prospects of Wind Blade Recycling Technology" introduces some mechanical recycling, pyrolysis recycling, chemical recycling and other methods, but does not mention the application in gel balls. Summary of the invention

[0005] In order to achieve the above-mentioned purpose, 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 activated sludge embedded particles, which can effectively realize the immobilization of activated sludge and enhance the mechanical strength of the gel balls. 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 reaction device, introducing sewage into the reactor to acclimate the nitrified sludge to obtain acclimatized nitrified sludge, 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) Add the mixed solution dropwise to a saturated boric acid solution of calcium chloride to form spherical particles, then take out the spherical particles and transfer them to Na 2 SO 4 The gel balls are cross-linked and solidified in an aqueous solution, and then the gel balls are taken out, cleaned, 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, in step (1), the particle size of the fan blade material powder 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 sewage in step (2) include 300-350 mg / L COD, 4-5 mg / L TP, trace elements and 25-45 mg / L NH 4 + -N.

[0017] Furthermore, the composition of trace elements includes 2-3 mg / LCaCl 2 .2H 2 O, 2~3mg / LMgSO 4 .7H 2 O.

[0018] 0.6~1mg / LFeCl 2 .4H 2 O, 0.6~1mg / LCoCl 2 .6H 2 O, 0.15~0.2mg / LMnCl 2 .4H 2 O.

[0019] 0.009~0.01mg / LCuCl 2 .2H 2 O, 0.015~0.02mg / LZnCl 2 , 0.015~0.02mg / LHBO 3 ,

[0020] 0.027~0.03mg / L(NH 4 ) 6 Mo 7 O 24 .4H 2 O, 0.015~0.02mg / LNiCl 2 .6H 2 O. 0.3~0.5mg / LEDTA (tripex 2).

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

[0022] Furthermore, aeration is required during the domestication 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 domestication, and aeration is performed again after an interval of 15 to 20 hours.

[0023] Furthermore, the acclimatization 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, in step (4), Na 2 SO 4 Na in aqueous solution 2 SO 4 The concentration is 0.5~1mol / L.

[0031] Furthermore, in step (4), the temperature of cross-linking and curing is 0 to 5° C., and the time of cross-linking and curing 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 wastewater used in the batch culture method in step (5) contains 300-350 mg / L COD, 4-5 mg / L TP, trace elements, and 25-45 mg / L NH 4 + -N.

[0034] Furthermore, the composition of trace elements includes 2-3 mg / LCaCl 2 .2H 2 O, 2~3mg / LMgSO 4 .7H 2 O.

[0035] 0.6~1mg / LFeCl 2 .4H 2 O, 0.6~1mg / LCoCl 2 .6H 2 O, 0.15~0.2mg / LMnCl 2 .4H 2 O.

[0036] 0.009~0.01mg / LCuCl 2 .2H 2 O, 0.015~0.02mg / LZnCl 2 , 0.015~0.02mg / LHBO 3 ,

[0037] 0.027~0.03mg / L(NH 4 ) 6 Mo 7 O 24 .4H 2 O, 0.015~0.02mg / LNiCl 2 .6H 2 O. 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 intake 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 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 materials, 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 ball can be used in the fields of environmental remediation, biodegradation, toxicity warning devices, etc., 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 good biocompatibility. Therefore, the gel ball can efficiently embed activated sludge and is suitable for toxicity warning devices to ensure the stability and accuracy of their operation. BRIEF DESCRIPTION OF THE DRAWINGS

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

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

[0046] The preferred embodiments of the present invention are described below. It should be understood that the embodiments are for better explaining the present invention and are not used 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 wind turbines, and the original manufacturer was Sinoma Technology Co., Ltd. The blades were 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 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 domesticated in the SBR system (volume 2L). During the domestication period, the influent COD was set to 300mg / L, TP to 4mg / L, and NH 4 + -N concentrations were 25, 35, and 45 mg / L, respectively, to adjust the carbon-nitrogen ratio and promote the growth of nitrifying bacteria. In addition, trace elements were added, as shown in Table 1, with an addition amount of 0.5 mL / L, to facilitate the reproduction of microorganisms in the activated sludge. During the process, Na 2 CO 3 To maintain the pH of wastewater between 7.5 and 8.5, which is suitable for the survival of nitrifying bacteria. Aeration is required for 5.5 hours a day, and sedimentation is carried out for 30 minutes. Then the supernatant is discharged and the newly prepared sewage is added for further domestication. After an interval of 19 hours, the aeration, sedimentation, drainage and water replenishment operations are repeated. After 15 days, domesticated nitrifying 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) is mixed with deionized water in a mass ratio of 1:9, heated on an induction cooker for 2-3 hours, and stirred continuously to ensure that the polyvinyl alcohol particles are completely dissolved, and then cooled to room temperature to obtain a polyvinyl alcohol solution. The domesticated nitrified sludge is centrifuged to obtain the precipitate, and the precipitate is washed with brine 2 to 3 times to obtain nitrified sludge. Then the nitrified sludge, polypropylene oxide (PPG), and polyvinyl alcohol solution are mixed in a volume ratio of 10:0.3:89.7, and the fan blade material powder is added and stirred evenly to obtain a mixed solution, in which the fan blade material powder accounts for 5wt% of the total mass of the mixed solution. The mixed solution is then added dropwise to a saturated boric acid solution containing 2wt% calcium chloride to form spherical particles. The spherical particles are then transferred to 0.5mol / L Na 2 SO 4 The gel balls were then taken out and washed with a 0.9wt% NaCl aqueous solution to remove the residual boric acid, and then freeze-thawed for 3 times in a -20℃ refrigerator to enhance their mechanical strength. Each freeze-thaw cycle was frozen for 8 hours and then taken out for 4 hours of thawing. Finally, the frozen and thawed gel balls were washed with deionized water, soaked in simulated domestic sewage, and stored at 4℃ for later 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 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 the microbial activity that may be caused 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 NH 4 + -N, 8 cycles (10 hours per cycle) of recovery were carried out by 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, 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 proposed 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 the recycling of resources, 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 the main materials for embedding gel particles of activated sludge

[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 gel balls. Retired wind turbine blade materials are mainly made of composite materials such as glass fiber reinforced plastics, which have the advantages of high strength and corrosion resistance, but they are difficult to degrade and bring pressure to 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 ball is 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 ball and improve its immobilization efficiency for activated sludge. In contrast, other commonly used gel materials, such as agar, calcium alginate, etc., although they also have certain biocompatibility, have poor mechanical strength, are difficult to withstand external forces such as aeration scouring, and are easily broken, resulting in 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 with both environmental protection 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 Embedding Gel Balls in Activated Sludge

[0069] The physical and chemical properties of unmodified gel balls, such as thermal stability, pore morphology, functional groups, and ammonia-oxygen mass transfer performance, are relatively poorer than those of modified gel balls. In addition, the modified gel balls have better mechanical strength and lower average pore size, and can better wrap the sludge. Polypropylene oxide (PPG), as a commonly used biomedical material, can effectively improve the performance of gel balls by adding it to activated sludge-embedded gel balls prepared by polyvinyl alcohol (PVA). The introduction of PPG can enhance the thermal stability of gel balls, making them less likely to deform or decompose under high temperature conditions, thereby ensuring the long-term use of gel balls. In addition, PPG can also significantly improve the mechanical strength of gel balls, making them more durable and able to withstand external forces such as aeration scouring, reducing the breakage of gel balls and the loss of activated sludge. At the same time, the gel balls modified with PPG have a larger total pore volume and a better pore structure, which is conducive to the transfer of nutrients and metabolic wastes, and provides a more suitable environment for the growth and metabolism of microorganisms. In addition, PPG also has good biocompatibility, does not produce toxicity to microorganisms, and ensures 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, wherein only the fan blade material powder was omitted.

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

[0075] The test results show that the gel balls prepared in Example 3 have a very small mass loss of 1.1166% at room temperature (30-50°C), indicating that the gel particles have good thermal stability at room temperature and can maintain the amount of activated sludge microorganisms to ensure continuous and stable operation in the toxicity warning device. However, the gel balls prepared in Comparative Example 4 have a large mass loss of 4.2674% at room temperature (30-50°C), which cannot 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 are more advantageous 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 balls were prepared and activated by referring to the steps of Examples 2 and 3, wherein only the volume ratio of nitrified sludge, polypropylene oxide and polyvinyl alcohol solution was adjusted to 10:1:89.

[0082] After the preparation, the pore structure of the gel ball was tested using a Belsorp-Max fully automatic specific surface area and pore distribution tester (MicrotracBEL, Japan). The AUR test method was to place the gel ball in an iodine volume bottle and add an appropriate amount of NH 4 Cl and NaHCO 3 , so that the ammonia nitrogen concentration reaches 25 mg / L, aerate and maintain DO at about 2 mg / L, and constantly 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 is measured, and the ammonia oxidation rate is calculated in combination with the concentration of activated sludge in the mixed solution.

[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 sphere prepared in Example 3 is 2.4NH 4 + -N / (g VSS·h), while the gel sphere AUR prepared in Comparative Example 5 only had 1.9NH 4 + -N / (g VSS·h), so excessive use of polypropylene oxide will harm the embedded sludge. In comparison, the gel spheres 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 TGA5500 thermogravimetric analyzer (TA, USA) at a temperature of 30-500°C and a heating rate of 10°C / min; BET using Belsorp-Max fully automatic specific surface and pore distribution measuring instrument (MicrotracBEL, Japan); ammonia and oxygen mass transfer characteristics are calculated 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; q 1 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 have a very small mass loss of 1.1166% at room temperature (30-50°C), indicating that the gel particles have good thermal stability at room temperature and can operate stably in the toxicity warning device. However, the gel spheres prepared in Comparative Example 6 have a large 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 spheres 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; 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 spheres 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 have a very small mass loss of 1.1166% at room temperature (30-50°C), indicating that the gel particles have good thermal stability at room temperature and can operate stably in the toxicity warning device. However, the gel spheres prepared in Comparative Example 6 have 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 spheres 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; 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 spheres prepared in Example 3 have more advantages.

[0106] The embodiments provided above are not intended to limit the scope of the present invention, and the steps described are not intended to limit the execution order thereof. Those skilled in the art may make obvious improvements to the present invention in combination with existing common knowledge, which also 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 reaction device, introducing sewage into the reactor to acclimate the nitrified sludge to obtain acclimatized nitrified sludge, 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 85-95wt%; 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 4-6wt%; (4) adding the mixed solution dropwise to a saturated boric acid solution of calcium chloride to form spherical particles, taking out the spherical particles and transferring them to a Na2SO4 aqueous solution for cross-linking and solidification to obtain gel balls, taking out the gel balls, washing them, and performing a freeze-thaw cycle; (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, characterized in that 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; the composition of trace elements includes 2-3mg / LCaCl2.2H2O, 2-3mg / LMgSO4.7H2O, 0.6-1mg / LFeCl2.4H2O, 0.6-1mg / LCoCl2.6H2O, 0.15-0.2mg / LMnCl2.4H2O, 0.009-0.01mg / LCuCl2.2H2O, 0.015-0.02mg / LZnCl2, 0.015-0.02mg / LHBO3, 0.027-0.03mg / 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, characterized in that In step (2), aeration is required during the acclimation process; 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, characterized in that 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, characterized in that 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, characterized in that The freeze-thaw cycle process 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; the composition of trace elements includes 2-3mg / LCaCl2.2H2O, 2-3mg / LMgSO4.7H2O, 0.6-1mg / LFeCl2.4H2O, 0.6-1mg / LCoCl2.6H2O, 0.15-0.2mg / LMnCl2.4H2O, 0.009-0.01mg / LCuCl2.2H2O, 0.015-0.02mg / LZnCl2, 0.015-0.02mg / LHBO3, 0.027-0.03mg / 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, characterized in that 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 intake 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. An activated sludge gel ball prepared according to the method according to any one of claims 1 to 8.

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

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