Latex skeleton aerobic granular sludge and preparation method thereof

Abstract

The invention discloses latex skeleton aerobic granular sludge and a preparation method thereof, and belongs to the technical field of sewage treatment. The aerobic granular sludge takes a porous natural latex carrier as a core skeleton, anaerobic sludge is fixed on the carrier, and after being mixed and wrapped with a sodium alginate solution, the mixture is dropwise added into a calcium chloride solution to be cured to form gel particles. The preparation method comprises the following steps: crushing the natural latex, screening to obtain particles with the particle size of 0.4-1.2 mm, and soaking the particles in alkali liquor with the pH value of 10-12; the method comprises the following steps: centrifugally concentrating anaerobic sludge to 10000 to 20000 mg / L; mixing the treated latex carrier, anaerobic sludge and a 1%-5% sodium alginate solution according to a volume ratio of 5: (2-5): (2-5); dropwise adding the mixture into a calcium chloride solution with the concentration of 3-7%, and curing to form gel particles; and putting the gel particles into a sewage treatment aerobic tank, injecting domestic sewage, and carrying out aeration domestication for 3-6 days until the particles become earthy yellow. The granular sludge prepared by the invention has the advantages of stable structure, good settling performance and high pollutant removal efficiency.

Description

Technical Field

[0001] This invention relates to the field of wastewater treatment technology, specifically to an aerobic granular sludge with a porous natural latex material as its framework and its preparation method. Background Technology

[0002] Aerobic granular sludge technology, as an advanced biological wastewater treatment process, shows broad application prospects in the field of wastewater treatment due to its excellent settling performance, high biomass retention capacity, and good resistance to shock loads. Compared with the traditional activated sludge process, aerobic granular sludge can achieve simultaneous nitrogen and phosphorus removal, and has a smaller footprint and is easier to operate and manage.

[0003] However, this technology still faces many challenges in its practical application: First, the cultivation and formation cycle of aerobic granular sludge usually takes several weeks to several months, and the stability during the start-up phase is poor; second, granular disintegration and structural collapse are prone to occur during long-term operation; in addition, the slow proliferation rate of granular sludge restricts its application effect in continuous flow processes.

[0004] Existing technologies typically employ the method of adding carrier materials to promote the granulation process. Chinese patent CN118771591A discloses a biomass-based polyurethane foam aerobic granular sludge, which enhances the treatment efficiency of pesticide wastewater through a foam carrier; Chinese patent CN114538625A proposes a fungal-algae symbiotic aerobic granular sludge, utilizing fungal mycelial balls as a framework to strengthen the granular structure. While these technical solutions improve the performance of granular sludge to some extent, they still suffer from problems such as insufficient carrier biocompatibility, difficulty in density control, and complex preparation processes.

[0005] Natural latex, as a natural polymer material, possesses a unique three-dimensional network porous structure, good mechanical strength, and biocompatibility, theoretically making it an ideal microbial carrier. However, there are currently no reports on the application of natural latex systems in the construction of aerobic granular sludge. In particular, how to utilize its material properties to overcome the shortcomings of existing carrier materials and achieve rapid cultivation and long-term stable operation of aerobic granular sludge remains a pressing technical challenge in this field. Summary of the Invention

[0006] The technical problem to be solved by the present invention

[0007] This invention aims to solve the technical problems of long formation cycle and poor structural stability of traditional aerobic granular sludge, and provides a latex-framework aerobic granular sludge that can be started up quickly, has a dense structure and stable performance, and a method for its preparation.

[0008] Technical solution of the present invention

[0009] To achieve the above objectives, the present invention adopts the following technical solution:

[0010] A latex-based aerobic granular sludge, characterized in that it comprises: a porous natural latex carrier as a core framework; and anaerobic sludge fixed on the porous natural latex carrier; the above materials are mixed and coated with sodium alginate solution, and then added dropwise to calcium chloride solution to solidify and form gel particles.

[0011] Furthermore, the porous natural latex carrier has a particle size of 0.4–1.2 mm and a density of 0.06–0.085 g / cm³.

[0012] Furthermore, the sludge is anaerobic sludge with a concentration of 10,000–20,000 mg / L.

[0013] Furthermore, the concentration of the sodium alginate solution is 1% to 5%.

[0014] A method for preparing aerobic granular sludge with a latex skeleton as described above, characterized by comprising the following steps:

[0015] S1. Carrier Pretreatment: Natural latex material is crushed and sieved to obtain latex particles with a particle size of 0.4–1.2 mm. These particles are then soaked in an alkaline solution with a pH of 10–12 for 1 hour, followed by washing and drying to obtain a hydrophilic porous natural latex carrier. S2. Anaerobic Sludge Pretreatment: Anaerobic sludge is collected from a wastewater treatment plant and centrifuged to obtain high-concentration anaerobic sludge with a concentration of 10,000–20,000 mg / L. S3. Carrier Composite: The porous natural latex carrier obtained in step S1 is mixed with the anaerobic sludge obtained in step S2 at a volume ratio of 5:(2–5) to obtain a composite carrier loaded with anaerobic sludge. S4. Gelation: The composite carrier obtained in step S3 is mixed with a 1%–5% sodium alginate solution at a volume ratio of 5:(2–5). (2-5) After mixing, add dropwise to a calcium chloride solution with a concentration of 3%-7% to solidify and form black gel particles loaded with anaerobic sludge; S5, acclimatization and cultivation: put the gel particles obtained in step S4 into the aerobic sewage tank and add domestic sewage for aeration for 3-6 days until the surface color of the particles turns yellowish-brown, thus forming the latex skeleton aerobic granular sludge.

[0016] Further, in step S4, the volume ratio of the porous natural latex carrier, the anaerobic sludge, and the sodium alginate solution is 5: (2-5): (2-5).

[0017] Further, in step S4, the concentration of the calcium chloride solution is 3% to 7%.

[0018] Beneficial effects of the present invention

[0019] Compared with the prior art, the latex-framework aerobic granular sludge and its preparation method provided by the present invention have the following significant advantages and advancements:

[0020] 1. High structural stability: The porous natural latex serves as a rigid framework, effectively supporting the microbial community and preventing the internal structure of the granules from collapsing and breaking. Verification through examples shows that the integrity coefficient of the prepared granular sludge can reach over 0.95.

[0021] 2. Rapid Start-up and Formation: The latex carrier provides a large specific surface area and an ideal attachment point for microorganisms. Combined with anaerobic sludge and aerobic acclimation, the cultivation cycle is significantly shortened. Comparative tests show that the method of this invention can form mature granular sludge in only 3-6 days, while the traditional method (without adding latex carrier) requires more than 20 days under the same conditions.

[0022] 3. Excellent settling performance: The latex carrier has a suitable density (0.06–0.085 g / cm³), resulting in gel particles with good settling properties. In the examples, the settling velocity of the granular sludge reached 70–85 m / h, which is much higher than that of traditional activated sludge (usually less than 10 m / h).

[0023] 4. High pollutant removal efficiency: Natural latex is non-toxic and conducive to microbial biofilm formation; the pre-loaded anaerobic sludge and subsequent aerobic acclimation form an anaerobic-aerobic synergistic microenvironment, which promotes the enrichment of functional bacteria. Attached Figure Description

[0024] Figure 1 This is the morphological structure of the mature aerobic granular sludge of this invention under a microscope.

[0025] Figure 2 These are the COD removal effects of three sets of examples.

[0026] Figure 3 These are the TN removal effects of three sets of examples. Detailed Implementation

[0027] The present invention will be further described in detail below with reference to embodiments and comparative examples, but the scope of protection of the present invention is not limited thereto.

[0028] Example 1

[0029] Carrier pretreatment (S1): The natural latex material is crushed and sieved to obtain latex particles with a particle size of 0.4–0.6 mm. These particles are soaked in a 1 mol / L NaOH solution (pH=11) for 1 hour, then washed with ultrapure water until neutral, and dried in a 60℃ oven to obtain a hydrophilic porous natural latex carrier. Anaerobic sludge pretreatment (S2): Anaerobic sludge is collected from a wastewater treatment plant and centrifuged to obtain high-concentration anaerobic sludge with a concentration of 10,000–12,000 mg / L. Carrier composite (S3): The porous natural latex carrier obtained in step S1, the anaerobic sludge obtained in step S2, and a 1% sodium alginate solution are mixed at a volume ratio of 5:2:2 to obtain a composite carrier loaded with anaerobic sludge. Gel solidification (S4): The composite carrier is dripped into a 3% calcium chloride solution using a dropper and solidified for 60 minutes to form black gel particles loaded with anaerobic sludge, which are then washed with deionized water. Acclimation and cultivation (S5): The gel particles obtained in step S4 are put into the aerobic tank of wastewater treatment, and domestic sewage is added for aeration. The aeration rate is controlled at a medium intensity, and the surface color of the gel particles changes from black to yellowish-brown for 3 days, thus forming the latex skeleton aerobic granular sludge.

[0030] Performance Verification: The granular sludge prepared in this embodiment has a dense structure and an average settling velocity of 75 m / h. Under wastewater conditions of COD=207 mg / L and TN=34 mg / L, the average COD removal rate was 79% and the average total nitrogen removal rate reached 66% during the stable operation phase.

[0031] Example 2

[0032] Carrier pretreatment (S1): Latex particles with a particle size of 1.0–1.2 mm obtained in step S1 of Example 1. Anaerobic sludge pretreatment (S2): Same as step S2 of Example 1, with a sludge concentration of approximately 18,000–20,000 mg / L after centrifugation. Carrier composite (S3): Porous natural latex carrier and 5% sodium alginate solution of anaerobic sludge are mixed at a volume ratio of 1:1:1 to obtain a composite carrier. Gel solidification (S4): The composite carrier is added dropwise to a 7% calcium chloride solution and solidified for 1 hour to form pre-prepared gel particles. Acclimation and cultivation (S5): The gel particles are placed in an aerobic tank, and domestic sewage is added for aeration for 6 days. The particles turn yellowish-brown, forming mature aerobic granular sludge.

[0033] Performance verification: Under the conditions of COD=207 mg / L and TN=34 mg / L, the granular sludge formation cycle was shortened to 6 days, the settling velocity was 85 m / h, the average COD removal rate was 83%, and the TN removal rate was 64%.

[0034] Example 3

[0035] Carrier pretreatment (S1): Same as step S1 in Example 1, sieve latex particles with a particle size of 0.8–1.0 mm. Anaerobic sludge pretreatment (S2): Same as step S2 in Example 1, the sludge concentration after centrifugation is approximately 18000 mg / L. Carrier composite (S3): Mix the porous natural latex carrier obtained in S1, the anaerobic sludge obtained in S2, and 4% sodium alginate solution at a volume ratio of 5:4:3 to obtain a composite carrier. Gel solidification (S4): Drop the composite carrier into a 6% calcium chloride solution and solidify for 1 hour to form gel particles with uniform particle size. Acclimation and cultivation (S5): Put the gel particles into an aerobic tank, add domestic sewage for aeration, continue for 4 days, the particle color turns yellowish-brown, forming a dense latex-skeleton aerobic granular sludge.

[0036] Performance verification: Under the conditions of COD=253 mg / L and TN=37 mg / L, the granular sludge formation cycle was shortened to 4 days, the average sludge settling velocity reached 73 m / h, the COD removal rate was 85%, and the total nitrogen removal efficiency reached 74%.

[0037] Compared with the traditional method (without adding latex carrier), under the same conditions, an equal amount of aerobic sludge was directly inoculated into an SBR reactor and the same acclimation and cultivation conditions (step S5) were adopted. The results showed that the sludge always existed in a flocculent form, and only a small number of irregular tiny particles began to appear on the 20th day. The structure was loose and the settling performance was poor (settling velocity <20 m / h).

[0038] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A latex-framed aerobic granular sludge, characterized in that, include: Porous natural latex carrier serves as the core framework; Anaerobic sludge is fixed on the porous natural latex carrier; the above materials are mixed with sodium alginate solution and then added dropwise to calcium chloride solution to solidify and form gel particles.

2. The latex-framed aerobic granular sludge according to claim 1, characterized in that, The porous natural latex carrier has a particle size of 0.4–1.2 mm and a density of 0.06–0.085 g / cm³.

3. The latex-framed aerobic granular sludge according to claim 1, characterized in that, The sludge is anaerobic sludge with a concentration of 10,000–20,000 mg / L.

4. The latex-framed aerobic granular sludge according to claim 1, characterized in that, The concentration of the sodium alginate solution is 1% to 5%.

5. A method for preparing latex-framework aerobic granular sludge as described in any one of claims 1 to 4, characterized in that, Includes the following steps: S1. Carrier Pretreatment: The natural latex material is crushed and sieved to obtain latex particles with a particle size of 0.4–1.2 mm. These particles are then soaked in an alkaline solution with a pH of 10–12 for 1 hour, followed by washing and drying to obtain a hydrophilic porous natural latex carrier. S2. Anaerobic Sludge Pretreatment: Anaerobic sludge is collected from a wastewater treatment plant and centrifuged to obtain high-concentration anaerobic sludge with a concentration of 10,000–20,000 mg / L. S3. Carrier Composite: The porous natural latex carrier obtained in step S1, the anaerobic sludge obtained in step S2, and a 1%–5% sodium alginate solution are mixed at a volume ratio of 5:

1. (2-5): Mix (2-5) to obtain a composite carrier loaded with anaerobic sludge; S4, gel solidification: Add the composite carrier to a calcium chloride solution with a concentration of 3%-7% to solidify and form black gel particles loaded with anaerobic sludge; S5, acclimatization and cultivation: Put the gel particles obtained in step S4 into the aerobic tank of wastewater treatment and add domestic sewage for aeration for 3-6 days until the surface color of the particles turns yellowish-brown, thus forming the latex skeleton aerobic granular sludge.

6. The method according to claim 5, characterized in that, In step S4, the volume ratio of the porous natural latex carrier, the anaerobic sludge, and the sodium alginate solution is 5: (2-5): (2-5).

7. The method according to claim 5, characterized in that, In step S4, the concentration of the calcium chloride solution is 3% to 7%.

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