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

Abstract

The invention discloses a method for strengthening the nitrogen removal effect of sulfur autotrophic denitrification based on a resin-based microbial carrier. The method comprises the following steps: S1, system construction: adding the resin-based microbial carrier and sulfur autotrophic bacteria into sewage to be treated to construct a sulfur autotrophic denitrification treatment system; s2, adjusting the system: adding S2O3 < 2-> into the sulfur autotrophic denitrification treatment system, and enabling the molar ratio n (S / N) of S2O3 < 2-> to NO3 <->-N in the sulfur autotrophic denitrification treatment system to be 0.9 + / -0.05; and S3, system operation. Resin is used as a carrier of sulfur autotrophic bacteria microorganisms, and the influence rules of the adsorption performance of NO3 <->-N and a sulfur source, the fixing capacity of the sulfur autotrophic bacteria and the system denitrification performance difference are compared and researched from the resin framework structure and the functional group type, so that an optimal resin selection scheme is obtained; technical support and theoretical reference are provided for research on high-efficiency treatment of low-concentration NO3 <->-N based on resin-based microbial carrier-sulfur autotrophic denitrification in the future.

Description

Technical Field

[0001] The invention relates to the technical field of total nitrogen treatment of water bodies, and in particular to a method for enhancing sulfur autotrophic denitrification effect based on a resin-based microbial carrier. Background Art

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

[0003] Sulfur autotrophic denitrification, as a green and environmentally friendly denitrification technology that does not require an external carbon source, has gradually gained widespread attention in the deep denitrification of secondary effluent from sewage treatment plants. However, the practical application of sulfur autotrophic denitrification still faces many challenges, especially the slow growth of sulfur autotrophic bacteria, susceptibility to water flow impact, and long reactor startup time, which limit its promotion and application in engineering.

[0004] Adding sulfur-containing microbial carriers to the sulfur autotrophic denitrification treatment system is one of the effective strategies to address the above challenges. This is because the sulfur-containing microbial carriers not only provide the sulfur autotrophic bacteria with the electron donors required for denitrification, but also provide support for their attachment and growth, thereby effectively reducing the negative impact of water flow impact on the growth of sulfur autotrophic bacteria. At present, common sulfur-containing carriers mainly include elemental sulfur and sulfide carriers, composite sulfur source carriers, and gel-embedded carriers. Elemental sulfur and sulfide carriers mainly include solid sulfur sources such as elemental sulfur and pyrite (Fe2S); composite sulfur source carriers are mixed with oyster shells, calcium carbonate, limestone and other substances on this basis to neutralize the hydrogen ions produced during the sulfur autotrophic process, thereby replenishing the alkalinity of the system; gel-embedded carriers are achieved by embedding microorganisms, sulfur sources, alkalinity supplements and activated carbon together with sodium alginate or hydrogel to achieve the fixation of microorganisms in the system.

[0005] However, as the reaction proceeds, the sulfur source in the elemental sulfur and sulfide carriers and the composite sulfur source carriers is gradually consumed, and the carriers gradually decompose; and after the sulfur source of the gel-embedded carrier is exhausted, the microorganisms in the gel cannot contact the external sulfur source, resulting in the loss of carrier function. At the same time, the problem of how to recycle such carriers and reload the sulfur source 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 limits their feasibility in engineering applications.

[0006] Compared with the method of fixing the sulfur source on the carrier (containing the sulfur source carrier), the use of a carrier that continuously enriches the added sulfur source can better ensure the continuous and stable operation of microorganisms, improve the performance of sulfur autotrophic denitrification, and is easy to operate, with better industrial application prospects. At the same time, considering the NO3 - -N concentration is low (about 5-20 mg / L), effectively enriching NO3 - -N is also a key strategy to improve the performance of sulfur autotrophic denitrification. Therefore, looking for good NO3 - Microbial carriers with the ability to enrich -N and sulfur sources will be the key to integrating the above two strategies to improve the performance of sulfur autotrophic denitrification.

[0007] Anion adsorption resin has unique cross-linking structure, positively charged functional groups and rich pore structure. - -N、S2O3 2- It has significant advantages in the enrichment of anions such as sulfur. In addition, some adsorption resins have good biocompatibility and can be used as microbial carriers to quickly enrich pollutants from water bodies, and it has recently been confirmed that these pollutants can be used as raw materials for microbial growth to achieve in situ degradation of pollutants. However, existing related research mainly focuses on the removal of organic pollutants, and there are no reports on the application of resin-based microbial carriers in the denitrification process. 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 needs to be further explored. Summary of the invention

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

[0009] The technical solution of the present invention is:

[0010] The method for enhancing the sulfur autotrophic denitrification effect based on a resin-based microbial carrier comprises the following steps:

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

[0012] The addition ratio of the sewage to be treated, the resin-based microbial carrier and the sulfur autotrophic bacteria is: 1L: 40-60g: 100-120mL;

[0013] S2. System adjustment: Add S2O3 to the sulfur autotrophic denitrification treatment system 2- and make S2O3 in the sulfur autotrophic denitrification treatment system 2- With NO3 - -N molar ratio n (S / N) is 0.9 ± 0.05;

[0014] S3. System operation: the sulfur autotrophic denitrification treatment system is operated continuously for 55 to 70 days, during which the sewage to be treated is replaced regularly.

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

[0016] Description: By optimizing the type of resin-based microbial carrier, it is beneficial to construct a microbial environment rich in electron donors and improve denitrification performance.

[0017] Furthermore, the resin-based microbial carrier in S1 needs to be pretreated before use, and the pretreatment method is: placing the resin-based microbial carrier in a 10-15wt% NaCl solution, placing it in a constant temperature shaker and oscillating it at a temperature of 30-32°C and a rotation speed of 150-200rpm for 3-4 hours, taking it out and washing it with deionized water for 3 times to complete the resin transformation, placing the transformed resin-based microbial carrier in methanol, placing it in a constant temperature shaker and oscillating it at a temperature of 30-32°C and a rotation speed of 150-200rpm for 3-4 hours, and taking it out and washing it with deionized water for 3 times.

[0018] Description: Remove organic impurities adsorbed on resin-based microbial carriers through pretreatment.

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

[0020] Furthermore, the S2O3 in the S2 2- With NO3 - When determining the molar concentration of -N, take 20 to 30 mL of the sulfur autotrophic denitrification treatment system sample and determine it by ion chromatography.

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

[0022] Furthermore, in S3, the first 15 days of operation of the sulfur autotrophic denitrification treatment system is the fixed bacteria stage, followed by the continuous operation stage:

[0023] S3-1, fixed bacteria stage: the temperature of the sulfur autotrophic denitrification treatment system is controlled at 30-32°C, the stirring speed is 150-200rpm, and the sewage is sampled and replaced every 20-24h. When the sewage is replaced, the sulfur autotrophic denitrification treatment system solution is centrifuged at 5000-6000rpm for 10-15min to precipitate free microorganisms in the sulfur autotrophic denitrification treatment system to avoid the loss of bacteria caused by water change. After the fixed bacteria stage, sulfur autotrophic bacteria are fixed on the resin-based microbial carrier;

[0024] S3-2, continuous operation stage: the temperature of the sulfur autotrophic denitrification treatment system is controlled at 30-32°C, the stirring speed is 150-200rpm, and the sewage is sampled and replaced every 20-24 hours. When replacing the sewage, it is allowed to stand for 15-20 minutes to precipitate the resin-based microbial carrier in the sulfur autotrophic denitrification treatment system, and the upper sewage is discharged.

[0025] The present invention also provides the application of the method for enhancing the sulfur autotrophic denitrification effect based on the resin-based microbial carrier, and the method is applied to treating the secondary effluent of the sewage treatment plant.

[0026] The beneficial effects of the present invention are:

[0027] (1) The method for enhancing sulfur autotrophic denitrification based on resin-based microbial carriers of the present invention uses resin as a carrier of sulfur autotrophic microorganisms, and based on the resin skeleton structure and functional group type, it can enhance the denitrification effect of NO3 - The effects of differences in the adsorption performance of -N and sulfur sources, the fixation capacity of sulfur autotrophic bacteria, and the denitrification performance of the system were compared and studied, thereby obtaining the optimal resin selection scheme, which will provide a basis for future research on the efficient treatment of low-concentration NO3 based on resin-based microbial carrier-sulfur autotrophic denitrification - -N provides technical support and theoretical reference.

[0028] (2) The results of the study on the method of enhancing sulfur autotrophic denitrification effect based on resin-based microbial carriers of the present invention show that polystyrene skeleton resin has more functional groups than polyacrylic acid resin and presents better nitrate nitrogen (NO3 - -N) and thiosulfate (S2O3 2- ) adsorption performance, the quaternary ammonium group shows stronger positive charge than the tertiary amine group, which is conducive to the adsorption of NO3 through electrostatic interaction - -N and S2O3 2- At the same time, S2O3 2- Because it has more negative charge, compared to NO3 - -N is easier to complete ion exchange on the resin with quaternary ammonium group, which is beneficial to construct a microbial environment rich in electron donors and improve the denitrification performance.

[0029] (3) The method for enhancing sulfur autotrophic denitrification based on a resin-based microbial carrier of the present invention uses D730 resin having a polyacrylic acid skeleton and a quaternary ammonium group as a carrier, because it can have good properties of the method for enhancing sulfur autotrophic denitrification based on a resin-based microbial carrier of the present invention and S2O3 2- The adsorption capacity and biocompatibility show the best denitrification performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 is the NO3 of the resin under different environments and n(S / N) in the experimental examples of the present invention. - -N adsorption amount;

[0031] Figure 2 is the S2O3 of the resin under different environments and n(S / N) in the experimental examples of the present invention. 2- Adsorption capacity;

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

[0033] Figure 4 is a comparison diagram of quaternary ammonium resin functional groups of different resins in the experimental examples of the present invention;

[0034] Figure 5 is a comparison diagram of tertiary ammonium resin functional groups of different resins in the experimental examples of the present invention;

[0035] Figure 6 The present invention is a flow chart of a method for enhancing sulfur autotrophic denitrification effect based on a resin-based microbial carrier. DETAILED DESCRIPTION

[0036] Example 1

[0037] Methods for enhancing sulfur autotrophic denitrification based on resin-based microbial carriers, such as Figure 6 As shown, the following steps are included:

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

[0039] The addition ratio of the sewage to be treated, the resin-based microbial carrier and the sulfur autotrophic bacteria is: 1L: 50g: 110mL, and the concentration of the sulfur autotrophic bacteria is 5×10 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 this application are commercially available bacteria, specifically purchased from the official corporate store of Water Country;

[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, placed in a constant temperature shaker and shaken for 3.5 hours at a temperature of 31°C and a speed of 180rpm, and then washed with deionized water for 3 times to complete the resin transformation. The transformed resin-based microbial carrier is placed in methanol, placed in a constant temperature shaker and shaken for 3.5 hours at a temperature of 31°C and a speed of 180rpm, and then washed with deionized water for 3 times;

[0042] S2. System adjustment: Add Na2S2O3·5H2O to the sulfur autotrophic denitrification treatment system, and adjust the S2O3 in the sulfur autotrophic denitrification treatment system. 2- With NO3 - -N molar ratio n (S / N) is 0.9, S2O3 2- With NO3 - When determining the molar concentration of -N, take 25 mL of the sulfur autotrophic denitrification treatment system sample and measure it by ion chromatography;

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

[0044] S3-1, fixed bacteria stage: the temperature of the sulfur autotrophic denitrification treatment system is controlled at 31°C, the stirring speed is 180rpm, and the sewage is sampled and replaced every 24h. When the sewage is replaced, the sulfur autotrophic denitrification treatment system solution is centrifuged at 5500rpm for 12min to precipitate free microorganisms in the sulfur autotrophic denitrification treatment system to avoid the loss of bacteria caused by water change. After the fixed bacteria stage, 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, the stirring speed is 180rpm, and the sewage is sampled and replaced every 24 hours. When replacing the sewage, it is left to stand for 16 minutes to precipitate the resin-based microbial carrier in the sulfur autotrophic denitrification treatment system, and the upper sewage is discharged.

[0046] Example 2

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

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

[0049] Example 3

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

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

[0052] Example 4

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

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

[0055] Example 5

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

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

[0058] Example 6

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

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

[0061] Example 7

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

[0063] The resin-based microbial carrier needs to be pretreated before use. The pretreatment method is: place the resin-based microbial carrier in a 10wt% NaCl solution, put it in a constant temperature shaker and oscillate it at 30°C and 150rpm for 3 hours, take it out and wash it 3 times with deionized water to complete the resin transformation, place the transformed resin-based microbial carrier in methanol, put it in a constant temperature shaker and oscillate it at 30°C and 150rpm for 3 hours, take it out and wash it 3 times with deionized water.

[0064] Example 8

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

[0066] The resin-based microbial carrier needs to be pretreated before use. The pretreatment method is: place the resin-based microbial carrier in a 15wt% NaCl solution, put it in a constant temperature shaker and oscillate it at 32°C and 200rpm for 4 hours, take it out and wash it 3 times with deionized water to complete the resin transformation, place the transformed resin-based microbial carrier in methanol, put it in a constant temperature shaker and oscillate it at 32°C and 200rpm for 4 hours, take it out and wash it 3 times with deionized water.

[0067] Example 9

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

[0069] S2. System adjustment: Add Na2S2O3·5H2O to the sulfur autotrophic denitrification treatment system, and adjust the S2O3 in the sulfur autotrophic denitrification treatment system. 2- With NO3 - -N molar ratio n (S / N) is 0.85, S2O3 2- With NO3 - When determining the molar concentration of -N, take 20 mL of the sulfur autotrophic denitrification treatment system sample and measure it by ion chromatography.

[0070] Example 10

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

[0072] S2. System adjustment: Add Na2S2O3·5H2O to the sulfur autotrophic denitrification treatment system, and adjust the S2O3 in the sulfur autotrophic denitrification treatment system. 2- With NO3 - -N molar ratio n (S / N) is 0.95, S2O3 2- With NO3 - When determining the molar concentration of -N, 30 mL of the sulfur autotrophic denitrification treatment system sample was taken and determined by ion chromatography.

[0073] Embodiment 11

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

[0075] S3, system operation: the sulfur autotrophic denitrification treatment system is operated continuously for 55 days, during which the sewage 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, followed by the 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 150rpm, and the sewage is sampled and replaced every 20h. When the sewage is replaced, the sulfur autotrophic denitrification treatment system solution is centrifuged at 5000rpm for 10min to precipitate free microorganisms in the sulfur autotrophic denitrification treatment system to avoid the loss of bacteria caused by water change. After the fixed bacteria stage, 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 150rpm, and the sewage is sampled and replaced every 20 hours. When replacing the sewage, it is allowed to stand for 15 minutes to precipitate the resin-based microbial carrier in the sulfur autotrophic denitrification treatment system, and the upper sewage is discharged.

[0078] Example 12

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

[0080] S3, system operation: the sulfur autotrophic denitrification treatment system is operated continuously for 70 days, during which the sewage to be treated is replaced regularly. The first 15 days of the operation of the sulfur autotrophic denitrification treatment system is the fixed bacteria stage, followed by 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 200rpm, and the sewage is sampled and replaced every 22h. When the sewage is replaced, the sulfur autotrophic denitrification treatment system solution is centrifuged at 6000rpm for 15min to precipitate free microorganisms in the sulfur autotrophic denitrification treatment system to avoid the loss of bacteria caused by water change. After the fixed bacteria stage, 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 200rpm, and the sewage is sampled and replaced every 22 hours. When replacing the sewage, it is left to stand for 20 minutes to precipitate the resin-based microbial carrier in the sulfur autotrophic denitrification treatment system, and the upper sewage is discharged.

[0083] Embodiment 13

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

[0085] Experimental example

[0086] First, we analyze the method of the present invention on NO3 in sewage -The adsorption of -N was tested under indoor conditions. 0.1 g of the pretreated resin was accurately weighed and placed in 20 mL of a mixed solution (where NO3 - -N concentration is 30mgL -1 , S2O3 2- The concentration is 192mgL -1 ), and then shaken in a constant temperature shaker at 30°C and 150 rpm for 4 h. After the reaction, the NO3 in the solution was measured. - -N and S2O3 2- Then, change the concentration of S2O3 in the solution 2- With NO3 - The molar ratio of -N (n(S / N) = 0.2, 0.4, 0.9, 1.5) was used to investigate the effect of different sulfur source addition 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 the resin skeleton structure and functional group type on the adsorption performance. The adsorption amount calculation formula is shown in formula (1). The resin adsorbs S2O3 2- With NO3 - The calculation formula of -N ratio is shown in formula (2). e Indicates the equilibrium adsorption capacity of the resin (mmolg -1 ), c0 and c e represent the initial concentration and equilibrium concentration of the solution (mmolL -1 ), V represents the volume of the solution (L), m represents the mass of the resin (g), Represents S2O3 of resin 2- Adsorption amount, Represents the NO3 of resin - -N adsorption amount.

[0087]

[0088] During the experiment, the solution Cl - 、NO3 - 、SO4 2- and S2O3 2- The concentration of isocyanate was determined by ion chromatography (Thermo Dionex Aquion-1100). The functional groups on the resin surface were analyzed by FTIR (Nicoleti S5, Thermo Fisher Nicolet) at 400-4000 cm -1 The morphology of the microbial community on the resin surface was observed by environmental scanning electron microscopy (FEIQuanta250FEG). The protein content was determined using the Lowry method, and the ATP concentration was determined using BacTiter-Glo TMMicrobial Cell Viability Assay kit was used for the high-throughput sequencing of 16s rRNA gene by Shanghai Meiji Biopharmaceutical Technology Co., Ltd., using primer 338F_806R in a PCR instrument ( PCR amplification was performed on an Illumina 9700 and high-throughput sequencing was performed on an Illumina Miseq. All data analyses were completed on the Meiji Biocloud platform.

[0089] Resin to NO3 - -N and S2O3 2- The adsorption performance of the resin-based microbial carrier-sulfur autotrophic denitrification process 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. To this end, we first studied the effects of polystyrene / polyacrylic acid skeleton and quaternary ammonium / tertiary amine groups on NO3 - -N and S2O3 2- The influence of adsorption performance, relevant experimental results such as Figures 1 to 5 As shown. Figure 1 and Figure 2 It can be seen that under the same n(S / N) condition (taking n(S / N) = 0.9 as an example), the four resins have a good effect on NO3 - -N and S2O3 2- The adsorption capacity is D201>D730>D301>D314.

[0090] Table 1 Physicochemical properties of resins

[0091]

[0092]

[0093] From the perspective of resin skeleton structure, both D201 and D730 resins contain quaternary ammonium groups (Table 1), but D201 has a stronger affinity for NO3 - -N and S2O3 2- The adsorption capacity of D730 (0.180mmolg-1 and 0.327mmolg-1) is significantly higher than that of D730 (0.055mmolg-1 and 0.297mmolg-1), which is mainly due to the difference in the number of quaternary ammonium functional groups caused by the different resin skeleton structures. Figure 4 It can be seen that the characteristic peaks of CN bonds in D201 resin (1055-990cm -1) is stronger than D730 resin, indicating that it has more ion exchange sites (quaternary ammonium groups), thus showing better adsorption performance. Similarly, both D301 and D314 resins have tertiary ammonium groups (Table 1), but D301 has a stronger adsorption performance for NO3 - -N and S2O3 2- The adsorption capacity (0.087mmolg-1 and 0.075mmolg-1) is better than that of D314 (0.008mmolg-1 and 0.016mmolg-1). The characteristic peaks of CN bonds in D301 resin (1055-990cm -1 ) is stronger than D314 resin ( Figure 5 ), indicating that it has more tertiary amine groups. This further shows that polystyrene skeleton resin has more ion exchange functional groups than polyacrylic acid skeleton resin, which is beneficial to improve adsorption performance. This may be because the degree of polymerization of polystyrene skeleton resin is usually higher than that of polyacrylic acid skeleton resin, resulting in more functional groups carried by it, which can also be further confirmed by the fact that the ion exchange capacity of polystyrene skeleton resin is higher than that of polyacrylic acid resin with the same functional groups (Table 1).

[0094] From the perspective of resin functional groups, both D201 and D301 have polystyrene skeletons (Table 1), but D201 has a stronger affinity for NO3 - -N and S2O3 2- The adsorption amount (0.180mmolg -1 and 0.327mmolg -1 ) is higher than D301 resin (0.087mmolg -1 and 0.075mmolg -1 ), which is mainly due to the difference in the types of functional groups of the two. The quaternary ammonium group of D201 shows 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- Produces stronger electrostatic interaction. In contrast, the tertiary amine group of D301 is weaker in basicity and produces relatively weaker electrostatic interaction. [25,26] This conclusion can also be seen from the effect of D730 on NO3 - -N and S2O3 2- The adsorption amount (0.055mmolg -1 and 0.297mmolg -1 ) is better than D314 (0.008mmolg -1 and 0.016mmolg -1 ) was further verified. Therefore, under the combined influence of the resin skeleton structure and functional groups, the four resins have a significant influence on NO3 - -N and S2O3 2-The adsorption capacity is D201>D730>D301>D314.

[0095] The denitrification performance of sulfur autotrophic bacteria is not only related to S2O3 2- and NO3 - -N concentration, and is 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 explored the effect of different n(S / N) ratios on the denitrification performance of S2O3 2- and NO3 - -N adsorption ratio, the experimental results are as follows Figure 3 As shown. Under the same n(S / N) conditions, the four resins have a significant effect on S2O3 2- and NO3 - The adsorption ratios of -N were D730>D314>D201>D301, and all of them were higher than those of sulfur autotrophic bacteria for S2O3 2- and NO3 - The theoretical utilization ratio of -N (n(S / N) = 0.8) indicates that the resin is more inclined to adsorb S2O3 with high valence. 2- This is mainly due to the stronger electrostatic force between high-valent ions and the resin, which makes them more easily 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, under the same conditions of the resin skeleton structure, the S2O3 2- and NO3 - The adsorption ratio of -N is higher than that of the resin with tertiary ammonium group (such as D730>D314 and D201>D301); and when the functional groups of the resins are the same, the polystyrene skeleton resin has more functional groups, which is beneficial to reduce S2O3 2- and NO3 - The competitive adsorption of N on the resin surface leads to the S2O3 2- and NO3 - The adsorption ratio of -N is lower than that of resins with polyacrylic acid skeleton (such as D730>D201 and D314>D301).

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

Claims

1. A method for enhancing sulfur autotrophic denitrification and denitrification effect based on resin-based microbial carriers, characterized in that: The following steps are involved: S1. System construction: adding resin-based microbial carriers and sulfur autotrophic bacteria to the sewage to be treated to construct a sulfur autotrophic denitrification treatment system; The addition ratio of the sewage to be treated, the resin-based microbial carrier 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 S2O3 in the sulfur autotrophic denitrification treatment system 2- With NO3 - -N molar ratio n (S / N) is 0.9 ± 0.05; S3. System operation: the sulfur autotrophic denitrification treatment system is operated continuously for 55 to 70 days, during which the sewage to be treated is replaced regularly.

2. The method for enhancing sulfur autotrophic denitrification and denitrification effect based on a resin-based microbial carrier according to claim 1, characterized in that: The resin-based microbial carrier in S1 is one or more of D201 polystyrene resin, D301 polystyrene resin, D730 polyacrylic resin or D314 polyacrylic resin.

3. The method for enhancing sulfur autotrophic denitrification and denitrification effect based on a resin-based microbial carrier according to claim 1, characterized in that: The resin-based microbial carrier in S1 needs to be pretreated before use, and the pretreatment method is: placing the resin-based microbial carrier in a 10-15wt% NaCl solution, placing it in a constant temperature shaker and oscillating it for 3-4 hours at a temperature of 30-32°C and a rotation speed of 150-200rpm, taking it out and washing it 3 times with deionized water to complete the resin transformation, placing the transformed resin-based microbial carrier in methanol, placing it in a constant temperature shaker and oscillating it for 3-4 hours at a temperature of 30-32°C and a rotation speed of 150-200rpm, and taking it out and washing it 3 times with deionized water.

4. The method for enhancing sulfur autotrophic denitrification effect based on resin-based microbial carrier according to claim 1, characterized in that: The concentration of sulfur autotrophic bacteria in S1 is 10 8 ~10 9 cfu / mL.

5. The method for enhancing sulfur autotrophic denitrification and denitrification effect based on resin-based microbial carriers according to claim 1, characterized in that: The S2S2O3 2- With NO3 - When determining the molar concentration of -N, take 20 to 30 mL of the sulfur autotrophic denitrification treatment system sample and determine it by ion chromatography.

6. The method for enhancing sulfur autotrophic denitrification and denitrification effect based on a resin-based microbial carrier according to claim 1, characterized in that: The S2S2O3 2- It is Na2S2O3·5H2O.

7. The method for enhancing sulfur autotrophic denitrification effect based on resin-based microbial carrier according to claim 1, characterized in that: In S3, the first 15 days of operation of the sulfur autotrophic denitrification treatment system is the fixed bacteria stage, followed by the continuous operation stage: S3-1, fixed bacteria stage: the temperature of the sulfur autotrophic denitrification treatment system is controlled at 30-32°C, the stirring speed is 150-200rpm, and the sewage is sampled and replaced every 20-24h. When the sewage is replaced, the sulfur autotrophic denitrification treatment system solution is centrifuged at 5000-6000rpm for 10-15min to precipitate free microorganisms in the sulfur autotrophic denitrification treatment system to avoid the loss of bacteria caused by water change. After the fixed bacteria stage, sulfur autotrophic bacteria are fixed on the resin-based microbial carrier; S3-2, continuous operation stage: the temperature of the sulfur autotrophic denitrification treatment system is controlled at 30-32°C, the stirring speed is 150-200rpm, and the sewage is sampled and replaced every 20-24 hours. When replacing the sewage, it is allowed to stand for 15-20 minutes to precipitate the resin-based microbial carrier in the sulfur autotrophic denitrification treatment system, and the upper sewage is discharged.

8. Use of the method according to any one of claims 1 to 7, characterized in that: It is used to treat secondary effluent from sewage treatment plants.

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