Phenol removal method for phenol-containing wastewater by adsorption coupling biodegradation

Abstract

A method for removing phenol from phenol-containing wastewater by adsorption coupled with biodegradation is disclosed. Porous gel beads (BC@PVA / PA) prepared from polyvinyl alcohol (PVA), phytic acid (PA), and biochar (BC) are added to an SBR bioreactor. BC@PVA / PA, which possesses phenol adsorption capabilities, can enhance the removal of phenol from wastewater through adsorption coupled with microbial degradation. A comparison of the purification effects of different treatments on phenol-containing wastewater—including inactivated sludge adsorption, BC@PVA / PA adsorption, activated sludge degradation, and BC@PVA / PA adsorption coupled with activated sludge degradation—reveals that BC@PVA / PA can rapidly adsorb phenol, alleviating the toxic inhibitory effect of high-concentration phenol on activated sludge. The adsorbed phenol can then be further desorbed and gradually removed by microbial degradation.

Description

Technical Field

[0001] This invention relates to the field of phenol-containing wastewater treatment technology, and specifically to a method for removing phenol from phenol-containing wastewater by adsorption coupled with biodegradation. Background Technology

[0002] Phenolic compounds are toxic organic compounds that have strong toxic effects on many organisms. They can cause certain degrees of poisoning to humans through direct contact with the skin and mucous membranes. If not handled properly, they can harm the environment and human health. Phenolic compounds are abundant in wastewater discharged from the coal chemical industry, making the treatment of phenol-rich coal chemical wastewater a top priority in current industrial wastewater management.

[0003] Currently, coal chemical wastewater treatment primarily employs a "oil removal-phenol and ammonia recovery-biochemical treatment-deep treatment" model. This process suffers from limitations such as high energy and chemical consumption, large sludge production, and long processing times. Even after physical and chemical oil removal, ammonia stripping, and phenol extraction, the biochemical unit still faces the stress of high phenol concentrations (still reaching 250-350 mg / L). -1 However, biological phenol removal methods suffer from technical limitations such as low efficiency and unstable operation. Therefore, there is an urgent need to develop efficient and stable phenol removal technologies.

[0004] Biochar (BC) possesses a large specific surface area and well-developed pores, enabling it to adsorb phenol from water. However, most biochar materials lack active adsorption sites on their surface, resulting in adsorption capacity and rate that do not meet practical application requirements. Therefore, existing technologies primarily focus on modifying the surface with acids, alkalis, or doping to increase functional groups and improve adsorption capacity and rate (e.g., patent CN113426411A). However, biochar adsorption of phenol from water merely transfers the pollutant from the aqueous phase to the solid phase; it does not fundamentally eliminate phenol, and desorbed phenol can easily cause secondary pollution. Microbial degradation of phenol is an effective technique for completely eliminating phenol, but microorganisms are easily inhibited by the toxicity of high concentrations of phenol, limiting its application. Biochar, with its porous structure and large specific surface area, can provide a place for microorganisms to aggregate, reproduce, and attach, thus it can be added to bioreactors to promote microbial enrichment. There are already studies on the removal of phenol from water by microorganisms immobilized on carriers, but the application of biochar-based carriers in phenol wastewater is relatively rare. Chinese patent (publication number: CN108017143A) discloses a technical method for the enhanced biodegradation of high-concentration phenol by polyurethane sponge-assisted phenol-degrading bacteria. This method only discloses the degradation of phenol by screening a single phenol-degrading strain, without examining the phenol degradation capacity of an activated sludge system of mixed phenol-degrading bacteria that has been domesticated for a long time. Furthermore, it has the disadvantages of poor carrier settling performance and relatively long adsorption time. Summary of the Invention

[0005] To overcome the shortcomings of the prior art, the present invention aims to provide a method for removing phenol from phenol-containing wastewater by adsorption coupled with biodegradation. This method involves loading BC onto gel beads synthesized by co-crosslinking polyvinyl alcohol (PVA) and phytic acid (PA) to prepare porous gel particles BC@PVA / PA, which possess both adsorption and easy water separation properties. These particles are then added to an SBR bioreactor, allowing for thorough mixing with the sludge and water, thus achieving highly efficient and stable adsorption coupled with microbial degradation to enhance phenol removal from wastewater.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] A method for removing phenol from phenol-containing wastewater by adsorption coupled with biodegradation includes the following steps:

[0008] 1) Cultivation of activated sludge that is tolerant to and degrades phenol: Activated sludge from the aerobic tank of a municipal wastewater treatment plant was collected as seed sludge. Under substrate conditions with ammonia nitrogen and phenol concentrations of 121-190 mg / L and 185-218 mg / L, respectively, activated sludge that is acclimatized and cultivated to be tolerant to and degrade phenol was cultivated.

[0009] 2) Preparation of BC@PVA / PA gel beads: PVA solution was prepared, BC and PA were added, and after removing air bubbles, BC@PVA / PA gel beads were synthesized in the mixed solution through chemical cross-linking.

[0010] 3) Adsorption coupled with biodegradation to remove phenol: 30-50% of BC@PVA / PA gel beads and 25-35% of activated sludge acclimated in step 1) to tolerate and degrade phenol were added to the SBR reactor, and adsorption coupled with biodegradation was carried out at 23±5℃ to remove phenol from the wastewater.

[0011] Step 1) Acclimation and cultivation of activated sludge to tolerate and degrade phenol, including the following steps:

[0012] 1.1) The activated sludge taken from the aerobic tank of the sewage treatment plant was rinsed with tap water and the sludge showed a uniform flocculated dispersion.

[0013] 1.2) The sludge treated in step 1.1) is inoculated into the SBR reactor, and synthetic phenol-containing wastewater is artificially prepared as influent to acclimate and cultivate activated sludge that is tolerant to and degrades phenol.

[0014] 1.3) Gradually increase the proportion of phenol in the wastewater to eventually obtain activated sludge with high phenol removal activity that is tolerant to and degrades phenol.

[0015] Steps 1.2)-1.3) Artificially prepare NH4 in phenol-containing wastewater +The -N concentration was increased from 121 mg / L to 190 mg / L, and the phenol concentration was increased from 185 mg / L to 218 mg / L.

[0016] The activated sludge described above, characterized by high phenol removal activity and tolerance to phenol degradation, has SS and VSS of 2300-5600 mg / L and 1800-3300 mg / L, respectively, and features large flocs and good settling performance. The SBR reactor conditions for cultivating this sludge are: DO range of 4.8–5.4 mg / L, stirring speed of 50–70 rpm, and temperature maintained at room temperature or 23±5℃. The average phenol removal rate of the SBR reactor is over 80%, and the average NH4+ removal rate is [not specified]. + -N removal rate is over 70%.

[0017] Step 2) Preparation method of BC@PVA / PA gel beads: First, add 20-30g of PVA to 200mL of distilled water to prepare a PVA solution with a mass fraction of 10-15%; Second, take 70mL of the prepared 3-6% NaOH solution and add 0.8-1.2g of biochar and 0.8-1.2g of phytic acid powder to it, stir for 1-2h to obtain a mixed solution, mix it with the PVA solution to form a first mixed solution; After homogenization, remove the air bubbles in the first mixed solution by ultrasound, and use a constant flow pump and syringe to drop the homogenized first mixed solution into 300mL of a second mixed solution containing 3-6% H3BO3, 1-3% CaCl2, and the remainder being water for chemical cross-linking, finally forming BC@PVA / PA gel beads.

[0018] The BC@PVA / PA gel beads prepared in step 2) have a compressive strength of 0.3–0.6 mPa and a specific surface area of ​​2–7 m². 2 / g, swelling ratio 300-450%, density 1.050-1.160g / cm³ 3 The sedimentation velocity is 3-6 cm / s, the diameter is 3-6 mm, it has good sedimentation performance in water, does not dissolve or break under continuous mechanical stirring, has good elasticity, and stable mechanical properties; the surface and interior of the gel beads are filled with well-developed pores.

[0019] Step 3) The SBR reactor operation process includes the following steps in sequence: water inlet, aeration and stirring, sedimentation, drainage, and idle. The water inlet time is 10-20 min, the aerobic aeration and stirring time is 1380-1400 min, the sedimentation time is 30-50 min, the drainage time is 10-20 min, and the idle time is 10-30 min. The HRT is 1.67-2.64 days, and the water exchange ratio is 40-60%.

[0020] Step 3) Using an artificially prepared phenol solution containing 800-1200 mg COD / L as the target wastewater, the adsorption-coupled biodegradation effect of phenol was evaluated. After 6 hours of adsorption and degradation, the phenol removal rate was 86.77-96.58%, and the COD removal rate was 50.86-59.13%.

[0021] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0022] This invention proposes a method for removing phenol from phenol-containing wastewater through adsorption coupled with biodegradation. BC@PVA / PA gel beads, prepared from a composite of PVA, PA, and BC, are added to an SBR bioreactor. The BC@PVA / PA gel beads, possessing phenol adsorption properties, can rapidly adsorb phenol, thus mitigating its toxicity and inhibitory effect on microorganisms. The adsorbed phenol can then be further desorbed and gradually degraded and removed by microorganisms. This invention provides an intensive treatment scheme for enhanced phenol removal from wastewater, with superior engineering application value and achieving ideal technical results. Adsorption coupled with biodegradation significantly accelerates phenol removal, with phenol removal rates of 60.03% and 83.98% after 1 hour and 3 hours, respectively, significantly superior to the 48.50% and 70.03% of simple biodegradation and the 52.18% and 62.21% of simple adsorption. Attached Figure Description

[0023] Figure 1 This is a schematic diagram illustrating the adsorption-coupled biodegradation principle of the present invention.

[0024] Figure 2 The following is a comparison diagram of the phenol removal effects of adsorption, biodegradation and adsorption coupled biodegradation in the examples, where (A) represents adsorption, (B) represents biodegradation and (C) represents adsorption coupled biodegradation. Detailed Implementation

[0025] The present invention will be further described below with reference to the embodiments.

[0026] Example 1, referring to Figure 1 A method for removing phenol from phenol-containing wastewater by adsorption coupled with biodegradation includes the following steps:

[0027] 1) Cultivation of activated sludge that is tolerant to and degrades phenol: Activated sludge from the aerobic tank of a municipal wastewater treatment plant was inoculated as seed sludge. Activated sludge that is tolerant to and degrades phenol was acclimatized and cultivated under the conditions of ammonia nitrogen and phenol concentrations of 180 mg / L and 200 mg / L, respectively.

[0028] 2) Preparation of BC@PVA / PA gel beads: First, 24g of PVA was added to 200mL of distilled water to prepare a 12% PVA solution. Second, 70mL of a 5% NaOH solution was prepared, and 1.0g of biochar and 1.0g of phytic acid powder were added. The mixture was stirred for 1.5h to obtain a mixed solution, which was then mixed with the PVA solution to form the first mixture. After homogenization, air bubbles in the first mixture were removed by ultrasonication. The homogenized first mixture was then added dropwise to 300mL of a second mixture containing 4% H3BO3, 1% CaCl2, and the remainder being water, using a constant flow pump and syringe for chemical cross-linking, ultimately forming BC@PVA / PA gel beads. The compressive strength of the prepared BC@PVA / PA gel beads was 0.5mPa, and the specific surface area was 5m². 2 / g, swelling ratio 350%, density 1.060g / cm³ 3 The settling velocity is 4.0 cm / s, exhibiting good settling performance in water. The diameter is ~5 mm, and it does not dissolve or break under continuous mechanical stirring. It has good elasticity and stable mechanical properties. The surface and interior of the gel beads are filled with well-developed pores.

[0029] The preparation method of the BC@PVA / PA gel beads includes the following steps:

[0030] 2.1) Preparation of raw material solution: Weigh 24g of polyvinyl alcohol using an electronic balance and dissolve it in 200mL of deionized water. Stir mechanically in an 85℃ water bath for 60min until completely dissolved to obtain PVA with a mass fraction of 12%.

[0031] 2.2) Preparation of NaOH catalyst: Dissolve 3.5g NaOH in 70mL of deionized water and stir evenly to prepare a 5% NaOH solution as a catalyst for the crosslinking reaction;

[0032] 2.3) Add 1.0 g of biochar and 1.0 g of phytic acid powder to the above NaOH solution and stir for 1.5 h;

[0033] 2.4) Add the mixed solution obtained in step 2.3) to the PVA solution prepared in step 1);

[0034] 2.5) After stirring evenly, let stand under ultrasonic radiation for 30 minutes to remove internal air bubbles and form a homogeneous sol containing BC, PVA and PA;

[0035] 2.6) Preparation of chemical crosslinking agent: Dissolve 40g H3BO3 and 10g CaCl2 in deionized water and make up to 1000mL to obtain a third mixed solution containing 4% H3BO3 and 1% CaCl2, which is used as the crosslinking agent for the crosslinking reaction;

[0036] 2.7) The homogeneous sol described in step 2.5) is dropped into the third mixture in step 2.6) using a constant flow pump and syringe to carry out chemical cross-linking, ultimately forming BC@PVA / PA gel beads;

[0037] 3) Evaluation of the effect of adsorption coupled with biological phenol removal:

[0038] The SBR reactor was not replaced the day before the experiment to ensure that the activated sludge used in the batch experiment consumed all the phenol added to the SBR reactor and was in a starved and active state, with SS and VSS of 2300 mg / L and 1800 mg / L, respectively, and had the characteristics of large flocs and good settling performance. The control conditions of the SBR reactor for cultivating the above sludge were: DO range of 4.8 mg / L, stirring speed of 50 rpm, and temperature maintained at room temperature or 23℃.

[0039] The SBR reactor operation cycle includes the following steps in sequence: water inlet, aeration and stirring, sedimentation, drainage, and idle. The water inlet time is 10 minutes, the aerobic aeration and stirring time is 1380 minutes, the sedimentation time is 30 minutes, the drainage time is 10 minutes, and the idle time is 10 minutes. The HRT is 1.67 days, and the water exchange ratio is constant at 60%.

[0040] a. Activated sludge degradation and phenol removal: 30% of the activated sludge acclimated and phenol-tolerant from step 1) was added to the SBR reactor. A controlled experiment was conducted using an artificially prepared phenol concentration of 429 mg / L (1020 mg COD / L) as the target wastewater. After 0.5 h, 1 h, 2 h, 3 h, and 6 h, the phenol removal rates of this system were 39.35%, 48.50%, 72.47%, 70.03%, and 77.35%, respectively, and the COD removal rates were 15.30%, 22.98%, 30.06%, 36.55%, and 41.72%, respectively. (See Appendix) Figure 2 (B) and Table 1.

[0041] b. Adsorption-coupled biodegradation phenol removal: 30% BC@PVA / PA gel beads and 25% activated sludge acclimated to and tolerant of phenol degradation (from step 1) were added to the SBR reactor. An artificially prepared phenol concentration of 338.1 mg / L (800 mg COD / L) was used as the target wastewater for adsorption-coupled biodegradation phenol removal experiments. After 0.5 h, 1 h, 2 h, 3 h, and 6 h, the phenol removal rates of this system were 56.00%, 64.10%, 78.94%, 83.98%, and 86.77%, respectively, and the COD removal rates were 18.27%, 27.22%, 41.34%, 46.69%, and 50.86%, respectively.

[0042] c. BC@PVA / PA Adsorption and Removal of Phenol: 30% BC@PVA / PA was added to the SBR reactor. An artificially prepared phenol solution with a concentration of 210 mg / L (500 mg COD / L) was used as the target wastewater for adsorption and removal of phenol. After 3 hours, the adsorption of phenol by the carrier tended to saturate. After 0.5 hours, 1 hour, 2 hours, and 3 hours, the phenol removal rates of this system were 44.40%, 52.18%, 60.03%, and 62.21%, respectively, and the COD removal rates were 39.77%, 47.95%, 53.80%, and 56.44%, respectively. (See Appendix) Figure 2 (A) and Table 1.

[0043] d. Phenol removal by adsorption of inactivated sludge: 30% sterilized activated sludge was added to the SBR reactor. A phenol solution with an artificial concentration of 429 mg / L (1020 mg COD / L) was used as the target wastewater for phenol removal by adsorption of sludge. After 6 hours, the phenol removal rate of this system was essentially 0, and the COD increased by 38.31% instead of decreasing (see Table 1).

[0044] according to Figure 2 According to Table 1, the adsorption-coupled biological phenol removal effect proposed in this invention is significantly better than that of inactivated sludge adsorption, BC@PVA / PA adsorption and activated sludge degradation.

[0045] Example 2, a method for removing phenol from phenol-containing wastewater by adsorption coupled with biodegradation, includes the following steps:

[0046] 1) Cultivation of activated sludge that is tolerant to and degrades phenol: Activated sludge from the aerobic tank of a municipal wastewater treatment plant was inoculated as seed sludge. Activated sludge that is tolerant to and degrades phenol was cultivated under the conditions of ammonia nitrogen and phenol concentrations of 121 mg / L and 185 mg / L, respectively.

[0047] 2) Preparation of BC@PVA / PA gel beads: First, 20g of PVA was added to 200mL of distilled water to prepare a 10% PVA solution. Second, 70mL of a 3% NaOH solution was prepared, and 0.8g of biochar and 0.8g of phytic acid powder were added. The mixture was stirred for 1.0h to obtain a mixed solution, which was then mixed with the PVA solution to form a first mixed solution. After homogenization, air bubbles in the first mixed solution were removed by ultrasonication. The homogenized first mixed solution was then added dropwise to 300mL of a second mixed solution containing 3% H3BO3, 2% CaCl2, and the remainder being water, using a constant flow pump and syringe for chemical cross-linking, ultimately forming BC@PVA / PA gel beads. Other preparation processes were the same as in Example 1. The compressive strength of the BC@PVA / PA gel beads was 0.3mPa, and the specific surface area was 2m². 2 / g, swelling rate 300%, density 1.050g / cm³ 3The settling velocity is 3.0 cm / s, exhibiting good settling performance in water. The diameter is ~3 mm. It does not dissolve or break under continuous mechanical stirring, has good elasticity, and stable mechanical properties. The surface and interior of the gel beads are filled with well-developed pores.

[0048] 3) The SS and VSS were 3800 mg / L and 2500 mg / L respectively, and the sludge had the characteristics of large flocs and good settling performance. The control conditions of the SBR reactor for cultivating the above sludge were: DO range of 5.0 mg / L, stirring speed of 60 rpm, and temperature maintained at room temperature or 18℃.

[0049] The SBR reactor operation cycle includes water inlet, aeration and stirring, sedimentation, drainage, and idle. The water inlet time is 15 min, the aerobic aeration and stirring time is 1400 min, the sedimentation time is 40 min, the drainage time is 15 min, and the idle time is 20 min. The HRT is 2.07 days, and the water exchange ratio is constant at 50%.

[0050] a. Adsorption coupled with biodegradation to remove phenol: The dosage of BC@PVA / PA gel beads and activated sludge for phenol degradation was changed to 40% and 30%, respectively, while other experimental conditions were the same as in Example 1. After 0.5h, 1h, 2h, 3h, and 6h, the phenol removal rates of this system were 60.31%, 67.80%, 81.64%, 85.18%, and 92.01%, respectively, and the COD removal rates were 21.76%, 29.96%, 43.19%, 49.63%, and 54.77%, respectively, as shown in Table 1.

[0051] Example 3, a method for removing phenol from phenol-containing wastewater by adsorption coupled with biodegradation, includes the following steps:

[0052] 1) Cultivation of activated sludge that is tolerant to and degrades phenol: Activated sludge from the aerobic tank of a municipal wastewater treatment plant was inoculated as seed sludge. Under the conditions of ammonia nitrogen and phenol concentrations of 190 mg / L and 218 mg / L, respectively, activated sludge that is acclimatized and cultivated to be tolerant to and degrade phenol was cultivated.

[0053] 2) Preparation of BC@PVA / PA gel beads: First, 30g of PVA was added to 200mL of distilled water to prepare a 15% PVA solution. Second, 70mL of a 6% NaOH solution was prepared, and 1.2g of biochar and 1.2g of phytic acid powder were added. The mixture was stirred for 2.0h to obtain a mixed solution, which was then mixed with the PVA solution to form a first mixed solution. After homogenization, air bubbles in the first mixed solution were removed by ultrasonication. The homogenized first mixed solution was then added dropwise to 300mL of a second mixed solution containing 6% H3BO3, 3% CaCl2, and the remainder being water, using a constant flow pump and syringe for chemical cross-linking, ultimately forming BC@PVA / PA gel beads. Other preparation processes were the same as in Example 1. The compressive strength of the BC@PVA / PA gel beads was 0.6mPa, and the specific surface area was 7m². 2 / g, swelling ratio 450%, density 1.160g / cm³ 3 The settling velocity is 6.0 cm / s, it has good settling performance in water, a diameter of ~6 mm, it does not dissolve or break under continuous mechanical stirring, it has good elasticity and stable mechanical properties; the surface and interior of the gel beads are filled with well-developed pores.

[0054] 3) The SS and VSS were 5600 mg / L and 3300 mg / L, respectively, and the sludge had the characteristics of large flocs and good settling performance. The control conditions of the SBR reactor for cultivating the above sludge were: DO range of 5.4 mg / L, stirring speed of 70 rpm, and temperature maintained at room temperature or 28℃.

[0055] The SBR reactor operation cycle includes the following steps in sequence: water inlet, aeration and stirring, sedimentation, drainage, and idle. The water inlet time is 20 minutes, the aerobic aeration and stirring time is 1400 minutes, the sedimentation time is 50 minutes, the drainage time is 20 minutes, and the idle time is 30 minutes. The HRT is 2.64 days, and the water exchange ratio is constant at 40%.

[0056] a. Adsorption-coupled biodegradation of phenol: The dosages of BC@PVA / PA gel beads and activated sludge for phenol degradation were changed to 50% and 35%, respectively, while other experimental conditions remained the same as in Example 1. After 0.5h, 1h, 2h, 3h, and 6h, the phenol removal rates of this system were 66.14%, 74.30%, 88.88%, 93.76%, and 96.58%, respectively, and the COD removal rates were 28.88%, 37.00%, 51.46%, 56.32%, and 59.13%, respectively (see Appendix). Figure 2 (C) and Table 1.

[0057] Table 1 Comparison of phenol removal efficiency at different stages in different groups

[0058]

[0059] In summary, this invention proposes a phenol removal process for phenol-containing wastewater enhanced by BC@PVA / PA carrier adsorption coupled with biodegradation. BC@PVA / PA adsorbs phenol, reducing the concentration of phenol in the wastewater and thus alleviating its toxicity to microorganisms. Biodegradation further promotes the desorption of phenol adsorbed by BC@PVA / PA, releasing new adsorption sites, thereby forming a "adsorption-desorption-biodegradation" cycle to enhance the continuous removal of phenol from wastewater. This process achieves superior technical effects compared to using BC@PVA / PA adsorption alone or activated sludge degradation alone, enabling efficient and stable phenol removal from wastewater.

Claims

1. A method for removing phenol from phenol-containing wastewater by adsorption coupled with biodegradation, characterized in that, Includes the following steps: 1) Cultivation of activated sludge that is tolerant to and degrades phenol: Activated sludge from the aerobic tank of a municipal wastewater treatment plant was collected as seed sludge. Under substrate conditions with ammonia nitrogen and phenol concentrations of 121-190 mg / L and 185-218 mg / L, respectively, activated sludge that is acclimatized and cultivated to be tolerant to and degrades phenol was cultivated. 2) Preparation of BC@PVA / PA gel beads: PVA solution was prepared, BC and PA were added, and after removing air bubbles, BC@PVA / PA gel beads were synthesized in the mixed solution through chemical cross-linking. The preparation method of BC@PVA / PA gel beads is as follows: First, prepare 200 mL of PVA solution with a mass fraction of 10-15%; second, take 70 mL of prepared NaOH solution with a mass fraction of 3-6%, and add 0.8-1.2 g of biochar and 0.8-1.2 g of phytic acid powder to it, stir for 1-2 h to obtain a mixed solution, and mix it with the PVA solution to form a first mixed solution; after homogenization, remove air bubbles in the first mixed solution by ultrasonication, and use a constant flow pump and syringe to drop the first mixed solution into 300 mL of a second mixed solution containing 3-6% H3BO3, 1-3% CaCl2, and the remainder being water to carry out chemical cross-linking, and finally form BC@PVA / PA gel beads; The BC@PVA / PA gel beads have a compressive strength of 0.3~0.6 mPa and a specific surface area of ​​2~7 m². 2 / g, swelling ratio 300~450%, density 1.050~1.160 g / cm³ 3 The sedimentation velocity is 3~6 cm / s, the diameter is 3~6 mm, it has good sedimentation performance in water, does not dissolve or break under continuous mechanical stirring, has good elasticity, and stable mechanical properties; the surface and interior of the gel beads are filled with well-developed pores. 3) Adsorption coupled with biodegradation to remove phenol: 30-50% of BC@PVA / PA gel beads and 25-35% of activated sludge acclimated in step 1) to tolerate and degrade phenol were added to the SBR reactor, and adsorption coupled with biodegradation was carried out to remove phenol from the wastewater at 25±5℃. The SBR reactor operation cycle includes the following steps in sequence: water inlet, aeration and stirring, sedimentation, drainage, and idle. The water inlet time is 10-20 min, the aeration and stirring time is 1380-1400 min, the sedimentation time is 30-50 min, the drainage time is 10-20 min, and the idle time is 10-30 min. The HRT is 1.67-2.64 days, and the water exchange ratio is 40-60%. Artificially prepared phenol solutions containing 800-1200 mg COD / L were used as target wastewater to evaluate the adsorption-coupled biodegradation effect of phenol. After 6 h of adsorption and degradation, the phenol removal rate was 86.77-96.58%, and the COD removal rate was 50.86-59.13%.

2. The method according to claim 1, characterized in that, Step 1) Acclimation and cultivation of activated sludge to tolerate and degrade phenol, including the following steps: 1.1) The activated sludge taken from the aerobic tank of the sewage treatment plant was rinsed with tap water and the sludge showed a uniform flocculated dispersion. 1.2) The sludge treated in step 1.1) is inoculated into the SBR reactor, and synthetic phenol-containing wastewater is artificially prepared as influent to acclimate and cultivate activated sludge that is tolerant to and degrades phenol; 1.3) Gradually increase the proportion of phenol in the wastewater to eventually obtain activated sludge with high phenol removal activity that is tolerant to and degrades phenol.

3. The method according to claim 2, characterized in that, Steps 1.2)-1.3) Artificially prepare NH4 in phenol-containing wastewater + The -N concentration was increased from 121 mg / L to 190 mg / L, and the phenol concentration was increased from 185 mg / L to 218 mg / L.

4. The method according to claim 3, characterized in that, The activated sludge described above, characterized by high phenol removal activity and tolerance to phenol degradation, has SS and VSS of 2300-5600 mg / L and 1800-3300 mg / L, respectively, and features large flocs and good settling performance. The SBR reactor conditions for cultivating this sludge are: DO range of 4.8-5.4 mg / L, stirring speed of 50-70 rpm, and temperature maintained at room temperature or 23±5℃. The average phenol removal rate of the SBR reactor is above 80%, and the average NH4+ removal rate is... + -N removal rate is over 70%.

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