Method for enhancing denitrification effect of sulfur autotrophic denitrification based on resin-based microbial carrier

Abstract

The application discloses a method for strengthening the effect of sulfur autotrophic denitrification based on a resin-based microbial carrier, and comprises the following steps: S1, system construction: resin-based microbial carriers and sulfur autotrophic bacteria are added into wastewater to be treated to construct a sulfur autotrophic denitrification treatment system; S2, system adjustment: S2O3 2‑ is added into the sulfur autotrophic denitrification treatment system to adjust the molar ratio n(S / N) of S2O3 2‑ to NO3 ‑ -N to 0.9±0.05; and S3, system operation. The application takes resin as a carrier of sulfur autotrophic bacteria, and studies the adsorption performance of NO3 ‑ -N and sulfur source, the fixing capacity of sulfur autotrophic bacteria, and the influence law of the difference in the denitrification performance of the system, so that the optimal resin selection scheme is obtained, which provides technical support and theoretical reference for future research on the resin-based microbial carrier-sulfur autotrophic denitrification for efficiently treating low-concentration NO3 ‑ -N.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of water body total nitrogen treatment, in particular to a method for enhancing the effect of sulfur autotrophic denitrification based on resin-based microbial carriers. BACKGROUND

[0002] The control of total nitrogen (TN) in water bodies is one of the important measures for the treatment of water body eutrophication. Among various sources of TN, the secondary effluent of wastewater treatment plants is one of the most important sources. Although the concentration of TN in the secondary effluent of wastewater treatment plants is relatively low (about 5-20 mg / L), the total amount of its emission is huge, and its contribution to water body TN pollution is particularly significant. In the secondary effluent of wastewater treatment plants, nitrate nitrogen (NO3 - -N) is the most important nitrogen form, therefore, effective treatment of nitrate nitrogen is the key to controlling water body total nitrogen pollution and alleviating eutrophication problems.

[0003] Sulfur autotrophic denitrification, as a green and environmentally friendly denitrification technology without additional carbon source, has gradually attracted widespread attention in the advanced denitrification of secondary effluent of wastewater treatment plants. However, the practical application of sulfur autotrophic denitrification still faces many challenges, especially the slow growth of sulfur autotrophic bacteria, the susceptibility to water flow impact, and the long start-up time of the reactor, which limits its popularization and application in engineering.

[0004] Adding sulfur source-containing microbial carriers to the sulfur autotrophic denitrification treatment system is one of the effective strategies to solve the above challenges, because the sulfur source-containing microbial carriers not only provide the sulfur autotrophic bacteria with the electron donor required for denitrification, but also provide support for their attached growth, thereby effectively reducing the negative impact of water flow on the growth of sulfur autotrophic bacteria. At present, common sulfur source-containing carriers mainly include elemental sulfur and sulfide carriers, composite sulfur source carriers, and gel-embedded carriers. Elemental sulfur and sulfide carriers mainly include elemental sulfur, pyrite (Fe2S), etc. solid sulfur sources; composite sulfur source carriers mix oyster shell, calcium carbonate, limestone, etc. with the above-mentioned solid sulfur sources, to neutralize the hydrogen ions generated in the sulfur autotrophic process, thereby supplementing the alkalinity of the system; gel-embedded carriers embed microorganisms, sulfur sources, alkalinity supplementing substances, activated carbon, etc. with sodium alginate or hydrogel, to realize the immobilization of microorganisms in the system.

[0005] However, with the progress of the reaction process, the sulfur sources in elemental sulfur and sulfide carriers and composite sulfur source carriers are gradually consumed, and the carriers are gradually decomposed; after the depletion of sulfur sources, the microorganisms in the gel-embedded carriers cannot contact the external sulfur sources, resulting in the loss of carrier function. At the same time, the problem of how to recover such carriers and reload sulfur sources has not been effectively solved. In addition, gel-embedded carriers also face problems such as organic matter release, gel dissolution and collapse during use, which further limit their feasibility in engineering applications.

[0006] Compared with the way of immobilizing sulfur source on the carrier (sulfur source-containing carrier), the carrier with continuously enriched additional sulfur source can guarantee the continuous and stable operation of microorganisms, improve the performance of sulfur autotrophic denitrification, and is simple to operate, and has better industrial application prospect. At the same time, considering that the concentration of NO3 - -N is low (about 5-20 mg / L), the effective enrichment of NO3 - -N is also a key strategy to improve the performance of sulfur autotrophic denitrification. Therefore, to find a microbial carrier with good NO3 - -N and sulfur source enrichment capacity will be the key to integrating the above two strategies to improve the performance of sulfur autotrophic denitrification.

[0007] Anion exchange resin has significant advantages in the enrichment of NO3 - -N, S2O3 2- and other anions due to its unique cross-linked structure, positively charged functional groups and rich pore structure. In addition, some adsorption resins show good biocompatibility, can be used as microbial carriers to rapidly enrich pollutants from water bodies, and make these pollutants as raw materials for microbial growth to realize in-situ degradation of pollutants. It has also been confirmed recently. However, the existing related researches mainly focus on the removal of organic pollutants, and the application of resin-based microbial carriers in the denitrification process has not been reported. At the same time, the influence of the skeleton structure and functional group type of the resin on the microbial carrier-sulfur autotrophic denitrification system also needs to be further discussed. SUMMARY

[0008] In view of the above problems, the present application provides a method for strengthening the effect of sulfur autotrophic denitrification based on resin-based microbial carriers.

[0009] The technical scheme of the present application is:

[0010] The method for strengthening the effect of sulfur autotrophic denitrification based on resin-based microbial carriers comprises the following steps:

[0011] S1, system construction: adding resin-based microbial carriers and sulfur autotrophic bacteria into the wastewater to be treated to construct a sulfur autotrophic denitrification treatment system;

[0012] Among them, the adding ratio of wastewater to be treated, resin-based microbial carriers and sulfur autotrophic bacteria is: 1L: 40-60g: 100-120mL;

[0013] S2, system adjustment: adding S2O3 2- to the sulfur autotrophic denitrification treatment system, and making the molar ratio n (S / N) of S2O3 2- to NO3 - -N in the sulfur autotrophic denitrification treatment system 0.9±0.05.

[0014] S3, system running: the sulfur autotrophic denitrification treatment system is continuously running for 55-70 days, and the wastewater to be treated is replaced regularly during the period.

[0015] Further, the resin-based microbial carrier in S1 is one or more of D201 polystyrene resin, D301 polystyrene resin, D730 polyacrylic acid resin or D314 polyacrylic acid resin.

[0016] Description: By selecting the type of resin-based microbial carrier, an electron donor-rich microbial environment is constructed, and the denitrification performance is improved.

[0017] Further, the resin-based microbial carrier in S1 needs to be pretreated before use. The pretreatment method is as follows: the resin-based microbial carrier is placed in a 10-15wt% NaCl solution, put into a constant temperature shaker at a temperature of 30-32℃ and a rotation speed of 150-200rpm for 3-4h, then washed with deionized water for 3 times, and the resin transformation is completed. The transformed resin-based microbial carrier is placed in methanol, put into a constant temperature shaker at a temperature of 30-32℃ and a rotation speed of 150-200rpm for 3-4h, then washed with deionized water for 3 times.

[0018] Description: By pretreatment, the organic impurities adsorbed on the resin-based microbial carrier are removed.

[0019] Further, the concentration of the sulfur autotrophic bacteria in S1 is 10 8 ~10 9 cfu / mL.

[0020] Further, the molar concentration of S2O3 2- and NO3 - -N in S2 is determined by taking 20-30mL of the sulfur autotrophic denitrification treatment system sample and determining by ion chromatography.

[0021] Further, the S2O3 2- in S2 is Na2S2O3·5H2O.

[0022] Further, in S3, the first 15 days of the running of the sulfur autotrophic denitrification treatment system is the fixed bacteria stage, and then is the continuous running stage:

[0023] S3-1, fixed bacteria stage: the temperature of the sulfur autotrophic denitrification treatment system is controlled at 30-32 DEG C, the stirring speed is 150-200 rpm, sampling and replacing the sewage every 20-24 hours, when replacing the sewage, the solution of the sulfur autotrophic denitrification treatment system is centrifuged at 5000-6000 rpm for 10-15 min to precipitate the free microorganisms in the sulfur autotrophic denitrification treatment system, so as to avoid the loss of bacteria caused by water replacement, and the resin-based microbial carrier is fixed with sulfur autotrophic bacteria after the fixed bacteria stage;

[0024] S3-2, continuous operation stage: the temperature of the sulfur autotrophic denitrification treatment system is controlled at 30-32 DEG C, the stirring speed is 150-200 rpm, sampling and replacing the sewage every 20-24 hours, when replacing the sewage, standing for 15-20 min to precipitate the resin-based microbial carrier in the sulfur autotrophic denitrification treatment system, and the sewage above can be discharged.

[0025] The application also provides the application of the method for strengthening the sulfur autotrophic denitrification effect based on the resin-based microbial carrier to the treatment of secondary effluent of a sewage treatment plant.

[0026] The beneficial effects of the application are:

[0027] (1) the method for strengthening the sulfur autotrophic denitrification effect based on the resin-based microbial carrier takes resin as the carrier of sulfur autotrophic bacteria, and the influence law of the differences in the adsorption performance of NO3 - -N and sulfur source, the sulfur autotrophic bacteria fixing capacity and the denitrification performance of the system is compared and studied, so that the optimal resin selection scheme is obtained, which provides technical support and theoretical reference for the future research on the resin-based microbial carrier-sulfur autotrophic denitrification for efficient treatment of low-concentration NO3 - -N.

[0028] (2) the research results of the method for strengthening the sulfur autotrophic denitrification effect based on the resin-based microbial carrier show that the polystyrene skeleton resin has more functional groups than the polyacrylic acid resin, and has more excellent adsorption performance of nitrate nitrogen (NO3 - -N) and thiosulfate (S2O3 2- ), and the quaternary ammonium group has stronger positive charge than the tertiary amine group, which is beneficial to the adsorption of NO3 - -N and S2O3 2- , at the same time, S2O3 2- has more negative charges, and is easier to complete ion exchange on the resin with quaternary ammonium group than NO3 - -N, so as to facilitate the construction of a rich electron donor microbial environment and improve the denitrification performance.

[0029] (3) The resin-based microbial carrier enhanced sulfur autotrophic denitrification effect method of the present application uses D730 resin with a polyacrylic acid skeleton and quaternary ammonium groups as the carrier, which can have good resin-based microbial carrier enhanced sulfur autotrophic denitrification effect method of the present application and S2O3 2- adsorption capacity and biocompatibility, and thus exhibits the best denitrification performance. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1 is the NO3 - adsorption amount of the resin under different environmental dosing n (S / N) in the experimental example of the present application.

[0031] Figure 2 is the S2O3 2- adsorption amount of the resin under different environmental dosing n (S / N) in the experimental example of the present application.

[0032] Figure 3 is the adsorption ratio of the resin under different environmental dosing n (S / N) in the experimental example of the present application.

[0033] Figure 4 is the quaternary ammonium resin functional group comparison chart of different resins in the experimental example of the present application.

[0034] Figure 5 is the tertiary ammonium resin functional group comparison chart of different resins in the experimental example of the present application.

[0035] Figure 6 is the flow chart of the resin-based microbial carrier enhanced sulfur autotrophic denitrification effect method of the present application. DETAILED DESCRIPTION

[0036] Example 1

[0037] The resin-based microbial carrier enhanced sulfur autotrophic denitrification effect method, as shown in the accompanying drawings, comprises the following steps: Figure 6

[0038] S1, system construction: adding resin-based microbial carriers and sulfur autotrophic bacteria to the wastewater to be treated to construct a sulfur autotrophic denitrification treatment system.

[0039] The addition ratio of the wastewater to be treated, the resin-based microbial carrier and the sulfur autotrophic bacteria is 1L:50g:110mL, and the bacterial concentration of the sulfur autotrophic bacteria is 5x10 8 cfu / mL.

[0040] The resin-based microbial carrier is D730 polyacrylic acid resin. It should be noted that the sulfur autotrophic bacteria used in the present application are commercially available and are purchased from the official enterprise store of Shui Zhiguo.

[0041] ​The resin-based microbial carrier needs to be pretreated before use. The pretreatment method is as follows: the resin-based microbial carrier is placed in a 12wt% NaCl solution, and is placed in a constant temperature shaker at a temperature of 31°C and a rotation speed of 180rpm for 3.5h. After taking out, it is washed with deionized water for 3 times to complete resin transformation. The transformed resin-based microbial carrier is placed in methanol, and is placed in a constant temperature shaker at a temperature of 31°C and a rotation speed of 180rpm for 3.5h. After taking out, it is washed with deionized water for 3 times.

[0042] S2, system adjustment: Na2S2O3·5H2O is added to the sulfur autotrophic denitrification treatment system, and S2O3 2- and NO3 - The molar ratio n(S / N) of S2O3 2- and NO3 - When the molar concentration of -N is determined, 25mL of the sulfur autotrophic denitrification treatment system sample is taken and determined by ion chromatography.

[0043] S3, system operation: the sulfur autotrophic denitrification treatment system is continuously operated for 60 days, during which the wastewater to be treated is replaced regularly. The first 15 days of the operation of the sulfur autotrophic denitrification treatment system are the fixed bacteria stage, and then the continuous operation stage:

[0044] S3-1, fixed bacteria stage: the temperature of the sulfur autotrophic denitrification treatment system is controlled at 31°C, and the stirring rotation speed is 180rpm. The sample is taken every 24h and the wastewater is replaced. When the wastewater is replaced, the sulfur autotrophic denitrification treatment system solution is centrifuged at 5500rpm for 12min to precipitate the free microorganisms in the sulfur autotrophic denitrification treatment system, so as to avoid the loss of strains caused by water replacement. After the fixed bacteria stage, the sulfur autotrophic bacteria are fixed on the resin-based microbial carrier;

[0045] S3-2, continuous operation stage: the temperature of the sulfur autotrophic denitrification treatment system is controlled at 31°C, and the stirring rotation speed is 180rpm. The sample is taken every 24h and the wastewater is replaced. When the wastewater is replaced, it is placed for 16min to precipitate the resin-based microbial carrier in the sulfur autotrophic denitrification treatment system, and the wastewater above can be discharged.

[0046] Example 2

[0047] The difference between this embodiment and example 1 is that:

[0048] The resin-based microbial carrier is D201 polystyrene resin.

[0049] Example 3

[0050] The difference between this embodiment and example 1 is that:

[0051] The resin-based microbial carrier is D301 polystyrene resin.

[0052] Example 4

[0053] The difference between this example and Example 1 is that:

[0054] The resin-based microbial carrier is D314 polyacrylic resin.

[0055] Example 5

[0056] The difference between this example and Example 1 is that:

[0057] The addition ratio of sewage to be treated, resin-based microbial carrier and sulfur autotrophic bacteria is 1L: 40g: 100mL, and the bacterial concentration of sulfur autotrophic bacteria is 10 8 cfu / mL.

[0058] Example 6

[0059] The difference between this example and Example 1 is that:

[0060] The addition ratio of sewage to be treated, resin-based microbial carrier and sulfur autotrophic bacteria is 1L: 60g: 120mL, and the bacterial concentration of sulfur autotrophic bacteria is 10 9 cfu / mL.

[0061] Example 7

[0062] The difference between this example and Example 1 is that:

[0063] The resin-based microbial carrier needs to be pretreated before use. The pretreatment method is as follows: the resin-based microbial carrier is placed in a 10wt% NaCl solution, put into a constant temperature shaker at a temperature of 30°C and a rotation speed of 150rpm for 3h, then washed with deionized water for 3 times, and the resin transformation is completed. The transformed resin-based microbial carrier is placed in methanol, put into a constant temperature shaker at a temperature of 30°C and a rotation speed of 150rpm for 3h, then washed with deionized water for 3 times.

[0064] Example 8

[0065] The difference between this example and Example 1 is that:

[0066] The resin-based microbial carrier needs to be pretreated before use. The pretreatment method is as follows: the resin-based microbial carrier is placed in a 15wt% NaCl solution, put into a constant temperature shaker at a temperature of 32°C and a rotation speed of 200rpm for 4h, then washed with deionized water for 3 times after taking out, and the resin transformation is completed. The resin-based microbial carrier after transformation is placed in methanol, put into a constant temperature shaker at a temperature of 32°C and a rotation speed of 200rpm for 4h, then washed with deionized water for 3 times after taking out.

[0067] Example 9

[0068] The difference between this example and Example 1 is that:

[0069] S2, system adjustment: Na2S2O3·5H2O is added to the sulfur autotrophic denitrification treatment system, and the molar ratio n(S / N) of S2O3 2- to NO3 - -N in the sulfur autotrophic denitrification treatment system is adjusted to 0.85. 2- to NO3 - When the molar concentration of S2O3

[0070] Example 10

[0071] The difference between this example and Example 1 is that:

[0072] S2, system adjustment: Na2S2O3·5H2O is added to the sulfur autotrophic denitrification treatment system, and the molar ratio n(S / N) of S2O3 2- to NO3 - -N in the sulfur autotrophic denitrification treatment system is adjusted to 0.95. 2- to NO3 - When the molar concentration of S2O3

[0073] Example 11

[0074] The difference between this example and Example 1 is that:

[0075] S3, system operation: the sulfur autotrophic denitrification treatment system is continuously operated for 55 days, and the wastewater to be treated is replaced regularly during the operation. The first 15 days of the operation of the sulfur autotrophic denitrification treatment system are the fixed bacteria stage, and the subsequent continuous operation stage:

[0076] S3-1, fixed bacteria stage: the temperature of the sulfur autotrophic denitrification treatment system is controlled at 30°C, the stirring speed is 150 rpm, sampling and replacing the sewage every 20 h, when replacing the sewage, the solution of the sulfur autotrophic denitrification treatment system is centrifuged at 5000 rpm for 10 min to precipitate the free microorganisms in the sulfur autotrophic denitrification treatment system, so as to avoid the loss of bacteria caused by water replacement, and after the fixed bacteria stage, the sulfur autotrophic bacteria are fixed on the resin-based microbial carrier;

[0077] S3-2, continuous operation stage: the temperature of the sulfur autotrophic denitrification treatment system is controlled at 30°C, the stirring speed is 150 rpm, sampling and replacing the sewage every 20 h, when replacing the sewage, the resin-based microbial carrier in the sulfur autotrophic denitrification treatment system is precipitated by standing for 15 min, and the sewage above can be discharged.

[0078] Example 12

[0079] The difference between this embodiment and example 1 is that:

[0080] S3, system operation: the sulfur autotrophic denitrification treatment system is continuously operated for 70 days, the sewage to be treated is replaced regularly during the operation, and the first 15 days of the operation of the sulfur autotrophic denitrification treatment system are the fixed bacteria stage, and then the continuous operation stage:

[0081] S3-1, fixed bacteria stage: the temperature of the sulfur autotrophic denitrification treatment system is controlled at 30-32°C, the stirring speed is 200 rpm, sampling and replacing the sewage every 22 h, when replacing the sewage, the solution of the sulfur autotrophic denitrification treatment system is centrifuged at 6000 rpm for 15 min to precipitate the free microorganisms in the sulfur autotrophic denitrification treatment system, so as to avoid the loss of bacteria caused by water replacement, and after the fixed bacteria stage, the sulfur autotrophic bacteria are fixed on the resin-based microbial carrier;

[0082] S3-2, continuous operation stage: the temperature of the sulfur autotrophic denitrification treatment system is controlled at 32°C, the stirring speed is 200 rpm, sampling and replacing the sewage every 22 h, when replacing the sewage, the resin-based microbial carrier in the sulfur autotrophic denitrification treatment system is precipitated by standing for 20 min, and the sewage above can be discharged.

[0083] Example 13

[0084] This embodiment is an application of the method for strengthening the effect of sulfur autotrophic denitrification based on the resin-based microbial carrier in example 1, and the method is applied to treat the secondary effluent of a sewage treatment plant.

[0085] Experimental example

[0086] First, we test the effect of the method of the present application on the removal of NO3 -- N adsorption was tested under indoor conditions, 0.1 g of the above pretreated resin was accurately weighed and placed in 20 mL of mixed solution (in which NO3 - - N concentration was 30 mg L -1 , S2O3 2- concentration was 192 mg L -1 ), then oscillated in a constant temperature shaker at 30 °C and 150 rpm for 4 h, and the NO3 - - N and S2O3 2- concentrations in the solution were measured after the reaction was completed. Then, the molar ratio of S2O3 2- to NO3 - in the solution (n(S / N) = 0.2, 0.4, 0.9, 1.5) was changed to investigate the effect of different sulfur source dosing ratios on the co-adsorption performance of the resin; different resins (D201, D301, D730 and D314) were selected for co-adsorption experiments to explore the effect of resin skeleton structure and functional group type on adsorption performance. The adsorption capacity calculation formula is shown in formula (1), and the calculation formula of the ratio of S2O3 2- to NO3 - - N adsorbed by the resin is shown in formula (2). Wherein, q e represents the equilibrium adsorption capacity of the resin (mmol g -1 ), c0and c e represent the initial concentration and equilibrium concentration of the solution (mmol L -1 ), respectively, V represents the solution volume (L), m represents the mass of the resin (g), represents the S2O3 2- adsorption capacity of the resin, represents the NO3 - - N adsorption capacity of the resin.

[0087]

[0088] The concentrations of Cl - , NO3 - , SO4 2- and S2O3 2- in the solution were determined by ion chromatography (Thermo Dionex Aquion-1100) during the experiment. The functional groups on the surface of the resin were determined by FTIR (Nicolet iS5, Thermo Fisher Nicolet) in the spectral range of 400-4000 cm -1 . The morphology of the microbial community on the surface of the resin was observed by environmental scanning electron microscopy (FEI Quanta 250 FEG). The protein content was determined by the Lowry method, and the ATP concentration was determined by BacTiter-Glo TMMicrobial Cell Viability Assay kit. High-throughput sequencing based on 16s rRNA gene was performed by Shanghai Meiji Biopharmaceutical Technology Co., Ltd. PCR amplification was performed on a PCR instrument (9700) using primers 338F_806R, and high-throughput sequencing was performed on an Illumina Miseq, and all data analysis was completed on the Meiji Biotech cloud platform. 9700 type) using primers 338F_806R, and high-throughput sequencing was performed on an Illumina Miseq, and all data analysis was completed on the Meiji Biotech cloud platform.

[0089] The adsorption performance of NO3 - -N and S2O3 2- on the resin is a key factor affecting the effect of the resin-based microbial carrier-sulfur autotrophic denitrification process, and the skeleton structure and functional group type of the resin play a core role in the adsorption performance. Therefore, we first studied the influence of polystyrene / polyacrylic acid skeleton and quaternary ammonium / tertiary amine groups on the adsorption performance of NO3 - -N and S2O3 2- , and the relevant experimental results are shown in Figures 1-5 , and Figure 1 , and Figure 2 It can be seen that under the same n(S / N) conditions (for example, n(S / N) = 0.9), the adsorption capacity of the four resins for NO3 - -N and S2O3 2- is in the order of D201 > D730 > D301 > D314.

[0090] Table 1 Physicochemical properties of resins

[0091]

[0092]

[0093] From the perspective of the skeleton structure of the resin, D201 and D730 resins both contain quaternary ammonium groups (Table 1), but the adsorption capacity of D201 for NO3 - -N and S2O3 2- (0.180 mmol g-1 and 0.327 mmol g-1) is significantly higher than that of D730 (0.055 mmol g-1 and 0.297 mmol g-1), which is mainly because the difference in the number of quaternary ammonium functional groups is caused by the difference in the skeleton structure of the resin. As can be seen from Figure 4 , the characteristic peak of C-N bond (1055-990 cm -1Compared to D730 resin, D301 exhibits stronger adsorption performance, indicating it possesses more ion exchange sites (quaternary ammonium groups). Similarly, both D301 and D314 resins possess tertiary ammonium groups (Table 1), but D301 shows better adsorption for NO3-. - -N and S2O3 2- The adsorption capacities (0.087 mmol g⁻¹ and 0.075 mmol g⁻¹) of D301 resin were superior to those of D314 (0.008 mmol g⁻¹ and 0.016 mmol g⁻¹). Furthermore, the characteristic peaks of CN bonds in D301 resin (1055-990 cm⁻¹) were observed. -1 It is stronger than D314 resin. Figure 5 The presence of more tertiary amine groups indicates that polystyrene-based resins have more ion-exchange functional groups than polyacrylic acid-based resins, thus improving adsorption performance. This is likely because polystyrene-based resins typically have a higher degree of polymerization than polyacrylic acid-based resins, resulting in more functional groups. This is further confirmed by the higher ion exchange capacity of polystyrene-based resins compared to polyacrylic acid resins with the same functional groups (Table 1).

[0094] From the perspective of resin functional groups, both D201 and D301 have a polystyrene skeleton (Table 1), but D201 is more sensitive to NO3. - -N and S2O3 2- The adsorption capacity (0.180 mmol g) -1 and 0.327 mmol g -1 The concentration was higher than that of D301 resin (0.087 mmol / g). -1 and 0.075 mmol g -1 This is mainly due to the difference in the types of functional groups between the two. The quaternary ammonium group of D201 exhibits stronger positive charge at pH 8.0 (the optimal pH for the survival and reproduction of sulfur autotrophic bacteria), thus reacting with NO3-. - -N and S2O3 2- The tertiary amine group of D301 exhibits stronger electrostatic interactions, while the tertiary amine group of D301 is less basic, resulting in relatively weaker electrostatic interactions. [25,26] This conclusion can also be drawn from the effect of D730 on NO3. - -N and S2O3 2- The adsorption capacity (0.055 mmol g) -1 and 0.297 mmolg -1 It is superior to D314 (0.008 mmol g) -1 and 0.016 mmolg -1 This was further verified. Therefore, under the combined influence of the resin skeleton structure and functional groups, the four resins showed different effects on NO3. - -N and S2O3 2-The adsorption capacity of the four resins was in the order of D201 > D730 > D301 > D314.

[0095] The denitrification performance of sulfur autotrophic bacteria is not only related to the concentrations of S2O3 2- and NO3 - -N, but also closely related to the n(S / N) ratio. As the n(S / N) ratio increases, the denitrification performance of sulfur autotrophic bacteria also improves. Based on this, we investigated the influence of different n(S / N) ratios on the adsorption ratio of S2O3 2- and NO3 - -N by resins, and the experimental results are shown in Figure 3 . Under the same n(S / N) conditions, the adsorption ratio of S2O3 2- and NO3 - -N by the four resins was in the order of D730 > D314 > D201 > D301, and was higher than the theoretical utilization ratio of S2O3 2- and NO3 - -N by sulfur autotrophic bacteria (n(S / N) = 0.8), indicating that resins tend to adsorb S2O3 2- with high valence. This is mainly due to the stronger electrostatic interaction between high valence ions and resins, which makes it easier for ions to be attracted to the resin surface for ion exchange. At the same time, since quaternary ammonium groups can produce stronger electrostatic interactions than tertiary ammonium groups, the adsorption ratio of S2O3 2- and NO3 - -N by resins with quaternary ammonium groups is higher than that by resins with tertiary ammonium groups (e.g., D730 > D314 and D201 > D301); and when the functional groups of the resins are the same, the polystyrene backbone resin has more functional groups, which helps to reduce the competitive adsorption of S2O3 2- and NO3 - -N on the resin surface, resulting in a lower adsorption ratio of S2O3 2- and NO3 - -N by resins with a polystyrene backbone (e.g., D730 > D201 and D314 > D301).

[0096] Therefore, D730 with a polyacrylic acid backbone and quaternary ammonium groups has the highest adsorption ratio of S2O3 2- and NO3 - -N. High adsorption ratio is conducive to building an electron-rich donor environment on the resin surface, thereby promoting its application as a microbial carrier to improve the denitrification performance of sulfur autotrophic systems. In addition, the experiments also show that as the n(S / N) ratio increases, the adsorption ratio of S2O3 2- and NO3 -The adsorption of S and N is also increased. This is because the increase of n(S / N) ratio leads to the increase of S2O3 2- concentration in the system, which is more favorable for the adsorption of S2O3 2- by the resin. However, too high n(S / N) ratio will increase the treatment cost, so the optimal n(S / N) ratio should be slightly higher than its theoretical value (0.8).

Claims

1. A method for enhancing the effect of autotrophic denitrification by sulfur based on a resin-based microbial carrier, characterized in that, The method comprises the following steps: S1, system construction: adding resin-based microbial carriers and sulfur autotrophic bacteria into sewage to be treated to construct a sulfur autotrophic denitrification treatment system; The resin-based microbial carriers are one or more of D201 polystyrene resin, D301 polystyrene resin, D730 polyacrylic acid resin or D314 polyacrylic acid resin; The adding ratio of the sewage to be treated, the resin-based microbial carriers and the sulfur autotrophic bacteria is 1L: 40-60g: 100-120mL; S2, System Adjustment: Add S2O3 to the sulfur autotrophic denitrification treatment system. 2- And make the S2O3 in the sulfur autotrophic denitrification treatment system 2- With NO3 - The molar ratio n(S / N) of -N is 0.9 ± 0.05; S3, system operation: continuously operating the sulfur autotrophic denitrification treatment system for 55-70 days, and periodically replacing the sewage to be treated during the operation.

2. The method for enhancing the effect of sulfur autotrophic denitrification according to claim 1, wherein, The resin-based microbial carriers in S1 need to be pretreated before use, and the pretreatment method is as follows: placing the resin-based microbial carriers in a 10-15wt% NaCl solution, putting them into a constant temperature shaker, oscillating them at a temperature of 30-32℃ and a rotation speed of 150-200rpm for 3-4h, washing them with deionized water for 3 times after taking them out, completing resin transformation, placing the resin-based microbial carriers after transformation in methanol, putting them into a constant temperature shaker, oscillating them at a temperature of 30-32℃ and a rotation speed of 150-200rpm for 3-4h, and washing them with deionized water for 3 times after taking them out.

3. The method for enhancing the effect of sulfur autotrophic denitrification according to claim 1, wherein the resin-based microbial carrier is a carrier having a resin-based support and a microorganism immobilized on the support. The bacterial concentration of the S1 sulfur autotrophic bacteria is 10 8 ~10 9 cfu / mL.

4. The method for enhancing the effect of sulfur autotrophic denitrification according to claim 1, wherein the resin-based microbial carrier is a carrier having a resin-based support and a microorganism immobilized on the support. The S2 in S2O3 2- with NO3 - When the molar concentration of -N is determined, 20-30 mL of the sample of the sulfur autotrophic denitrification treatment system is taken, and determination is performed by ion chromatography.

5. The method for enhancing the effect of sulfur autotrophic denitrification according to claim 1, wherein the resin-based microbial carrier is a carrier having a resin-based substrate and a microorganism immobilized on the substrate. S2O3 2- Na2S2O3·5H2O.

6. The method for enhancing the effect of sulfur autotrophic denitrification according to claim 1, wherein the resin-based microbial carrier is a resin-based carrier having a porous structure. In S3, the first 15 days of the operation of the sulfur autotrophic denitrification treatment system is a fixed bacteria stage, and then is a continuous operation stage: S3-1, fixed bacteria stage: controlling the temperature of the sulfur autotrophic denitrification treatment system at 30-32℃, and controlling the stirring rotation speed at 150-200rpm, sampling and replacing the sewage every 20-24h, centrifuging the solution of the sulfur autotrophic denitrification treatment system at 5000-6000rpm for 10-15min to precipitate free microorganisms in the sulfur autotrophic denitrification treatment system to avoid loss of bacteria caused by water replacement, and fixing the sulfur autotrophic bacteria on the resin-based microbial carriers after the fixed bacteria stage; S3-2, continuous operation stage: controlling the temperature of the sulfur autotrophic denitrification treatment system at 30-32℃, and controlling the stirring rotation speed at 150-200rpm, sampling and replacing the sewage every 20-24h, and placing the sulfur autotrophic denitrification treatment system for 15-20min to precipitate the resin-based microbial carriers in the sulfur autotrophic denitrification treatment system, and then discharging the sewage above to complete the replacement.

7. Use of the method according to any one of claims 1 to 6, characterized in that, The method is applied to treat secondary effluent of a sewage treatment plant.

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