Method for improving sulfur autotrophic denitrification and anaerobic ammonia oxidation coupled denitrification efficiency

Abstract

A method for improving the denitrification efficiency of a sulfur autotrophic denitrification and anaerobic ammonia oxidation coupling system comprises the following steps: S1, when the denitrification load is limited and the mass transfer rate in particles is reduced, determining the abundance of filamentous bacteria or determining the length of filaments outside sludge through a molecular biological technique to judge whether the filamentous bacteria overgrow or not; when the abundance ratio of the filamentous bacteria reaches 10%-50% or the length (FLA) of the filamentous substances outside the sludge is 10-50 microns, it can be judged that the filamentous bacteria grow excessively; and S2, continuously adding a hydroxylamine conditioning agent and / or a hydrazine conditioning agent into the reactor, and operating the reactor for 10-30 days. According to the method, excessive reproduction of filamentous bacteria in the coupling system can be effectively controlled, more importantly, the denitrification performance of the coupling system can be improved, the anaerobic ammonia oxidation activity is enhanced, and therefore the operation efficiency of the coupling system is promoted.

Description

Technical Field

[0001] This invention belongs to the field of wastewater biological treatment technology, specifically relating to a method for improving the efficiency of nitrogen removal through the coupling of sulfur autotrophic denitrification and anaerobic ammonia oxidation. Background Technology

[0002] Anaerobic ammonia oxidation technology can directly remove NH4 from wastewater. + -N and NO2 - The simultaneous conversion of -N to N2 offers advantages such as energy saving and low sludge production, and has attracted widespread attention in recent years. However, this technology requires stable NO2. - -N supply will generate NO3. - -N byproducts result in a maximum theoretical total nitrogen removal rate of only 89%, posing a challenge in practical applications. Sulfur-oxidizing bacteria (SOBs) can utilize reduced inorganic sulfur compounds (S... 2- S2O3 2- Denitrification occurs, and NO2 is steadily accumulated. - -N. SOB's growth rate of 0.27-0.04 g / h and biomass yield of 0.59-0.65 gVSS / gN are comparable to those of anaerobic ammonia-oxidizing bacteria. The synergistic effect of sulfur autotrophic denitrification and anaerobic ammonia oxidation can achieve efficient nitrogen removal from wastewater. This process is beneficial for reducing the carbon footprint of wastewater treatment plants and has good application prospects in the field of wastewater treatment under the current "dual carbon" background.

[0003] Both sulfur-autotrophic denitrifying bacteria and anaerobic ammonia-oxidizing bacteria are autotrophic. Maintaining these autotrophic microorganisms within the system and ensuring their functional stability under environmental stress conditions remains a challenge. The presence of sulfur-autotrophic filamentous bacteria can promote the rapid granulation of sulfur-autotrophic denitrification and anaerobic ammonia-oxidizing sludge into granular sludge, providing more diverse growth space for both types of autotrophic microorganisms and ensuring sufficient biomass and stable environmental stress tolerance within the coupled system. However, excessive growth of sulfur-autotrophic filamentous bacteria can lead to a decrease in the mass transfer rate of granular sludge, inhibit the activity of microorganisms within the sludge, thereby reducing denitrification efficiency and eventually causing granular disintegration. Therefore, taking effective measures to control the excessive growth of filamentous bacteria is a key condition for ensuring the efficient operation of the coupled system.

[0004] Common methods for controlling filamentous bacteria include physical methods, chemical methods, biological control, and process parameter adjustment. Physical methods include high-temperature shock and increased stirring. However, because anaerobic ammonia oxidizing bacteria, one of the functional bacteria in the coupled system, are sensitive to environmental changes and grow slowly, this method, while effective, may lead to difficulties in system recovery and increase equipment modification costs. Biological control includes introducing antagonistic filamentous bacteria and denitrifying bacteria. These methods may disrupt the bacterial balance and reduce the nitrogen removal contribution rate of anaerobic ammonia oxidizing bacteria in the coupled system, thus affecting the total nitrogen removal efficiency. Chemical methods include adding hydrogen peroxide, sodium hypochlorite, iron salts, and aluminum salts. These additives either risk disrupting dissolved oxygen levels and causing system collapse or disrupt the substrate supply within the system, further affecting the bacterial balance and impacting the system's nitrogen removal performance. Optimization methods such as controlling dissolved oxygen, reducing sludge age, and lowering the F / M ratio all have some negative impact on the sulfur autotrophic denitrification and anaerobic ammonia oxidation coupled system. Therefore, most of the above methods, while controlling filamentous bacteria, will have adverse effects on the system and cannot effectively improve the coupled nitrogen removal efficiency. Summary of the Invention

[0005] This invention addresses the problem of "the inability to simultaneously control filamentous bacteria growth and improve the contribution rate of anaerobic ammonia oxidation (ANAO) to total nitrogen removal" when using traditional methods to control excessive filamentous bacteria growth in coupled sulfur autotrophic denitrification and ANAO systems. This method not only effectively controls excessive filamentous bacteria growth within the coupled system, thus avoiding the decline in nitrogen removal efficiency caused by filamentous bacteria proliferation in the coupled granular sludge system, but also enhances ANAO activity, increasing the contribution rate of ANAO bacteria to total nitrogen removal, thereby improving the overall nitrogen removal performance of the coupled system. This method requires no changes to the reactor operation mode, no additional external mechanical facilities or physical fields such as heat or electricity, and does not involve the use of strong oxidizing substances or metal cations; it only utilizes intermediate products of nitrogen metabolism. It has advantages such as ease of use, simple operation, low cost, and good results.

[0006] A method for improving the nitrogen removal efficiency of a coupled sulfur autotrophic denitrification and anaerobic ammonia oxidation system includes the following steps: S1. When the denitrification load is limited and the mass transfer rate inside the particles decreases, the abundance of filamentous bacteria or the length of filamentous material outside the sludge can be measured by molecular biology techniques to determine whether filamentous bacteria are overgrown. When the abundance of filamentous bacteria reaches 10% to 50% or the length of filamentous material outside the sludge (FLA) is 10 to 50 μm, it can be determined that filamentous bacteria are overgrown. S2. Continuously add hydroxylamine regulators and / or hydrazine regulators into the reactor. The reactor can be run for 10-30 days.

[0007] In S1, a sulfur autotrophic denitrification and anaerobic ammonia oxidation coupled system using reducing sulfur-containing compounds as sulfur-containing electron donors is employed. An anaerobic reactor is used, with a mixture of sulfur autotrophic denitrification sludge and anaerobic ammonia oxidation coupled sludge as inoculum sludge in a mass ratio of (0.5:1~2:1). The reactor influent is S2O3. 2- NO3 - and NH4 + When -N, S2O3 2- NO3 - and NH4 + -N concentrations were 150~300 mgS / L, 60 mgN / L~200 mgN / L, and 100 mgN / L~250 mgN / L, respectively; temperature was 30~35℃; pH was 7.0~8.7; influent NaHCO3 concentration was 2.0 g / L~8 g / L; HRT was 2 h~48 h; and operating time was 20~60 days.

[0008] The reactor inlet water is S 2- NO3 - and NH4 + When -N, S 2- NO3 - and NH4 + -N concentrations were 200-300 mgS / L, 100-300 mgN / L, and 50-250 mgN / L, respectively; temperature was 30-35℃; pH was 7.0-8.7; influent NaHCO3 concentration was 2.0 g / L-8 g / L; HRT was 2 h-48 h; and operating time was 20-60 days.

[0009] Furthermore, in S1, when the denitrification load is limited, the decrease in the internal mass transfer rate of the particles refers to a total nitrogen removal load of 1.88 kgN / (m³). 3 ·d)~2.26kgN / (m 3 ·d), particle mass transfer rate 0.03 kgN / (m 3 ·d)~0.05kgN / (m 3 ·d); The total nitrogen removal load was significantly lower than the normal operating condition of 3.02 kgN / (m³). 3 ·d)~3.25kgN / (m 3 ·d) and particle mass transfer rate 0.12 kgN / (m 3 ·d)~0.15kgN / (m 3 ·d).

[0010] Furthermore, in S1, the abundance of filamentous bacteria is determined using molecular biology techniques, or the length of filamentous material outside the sludge is measured using effective methods. These molecular biology techniques include high-throughput sequencing of 16S rRNA, metagenomic sequencing, or quantitative PCR. Effective methods may be based on fluorescence in situ hybridization (FISH) staining or electron microscopy. The concentration of hydroxylamine regulator in S2 is 5 mg / L to 50 mg / L, and the concentration of hydrazine regulator is 3 mg / L to 50 mg / L. When hydroxylamine regulator and hydrazine regulator are added at the same time, the mass ratio of the two is 1:5 to 5:1, more preferably 1:3 to 3:1.

[0011] Furthermore, in S2, the added hydroxylamine regulator is one or more of hydroxylamine hydrochloride, hydroxylamine sulfate, hydroxylamine phosphate, hydroxylamine formate, and hydroxylamine acetate; preferably, it is hydroxylamine hydrochloride.

[0012] Furthermore, in S2, the added hydrazine-based regulator is one or more of hydrazine, hydrazine sulfate, hydrazine hydrate, methylhydrazine, and phenylhydrazine; preferably hydrazine and hydrazine hydrate.

[0013] Furthermore, in S2, the reactor operating conditions are maintained as follows: temperature 30–35℃, pH 8.3–8.7, and influent nitrogen load 3.50 kgN / (m³). 3 ·d)~3.77kgN / (m 3 •d) The influent NaHCO3 concentration is 2.0 g / L to 5 g / L, and the operating time is 15 to 25 days.

[0014] Furthermore, in S2, achieving effective control of overgrown filamentous bacteria and enhancing the activity of anaerobic ammonia-oxidizing bacteria means that the abundance of filamentous bacteria decreased by 15-95%, FLA decreased by 10-70%, and the total nitrogen removal rate increased by 5-30%.

[0015] Furthermore, in S2, after the reactor operated for 10-30 days, the internal mass transfer rate of the sludge particles decreased from 0.03 kgN / (m³) 3 ·d)~0.05kgN / (m 3 ·d) increased to 0.12 kgN / (m 3 ·d)~0.15kgN / (m 3 The activity of anaerobic ammonia oxidizing bacteria increased from 120-150 mg TN / g VSS·d to 155-170 mg TN / g VSS·d, and the total nitrogen removal load increased to 3.02 kg N / (m³). 3 ·d)~3.25kgN / (m 3 •d) effectively ensures the denitrification rate of granular sludge.

[0016] Stable operation phase S of the reactor 2- The removal rate reached over 99%, NO3 - The removal rate reached 93%, NH4 + The removal rate is greater than 85%, the total nitrogen removal rate is over 90%, and the contribution rate of anaerobic ammonia oxidation denitrification is consistently above 60%.

[0017] This invention employs an anaerobic reactor, using sulfur autotrophic denitrification and anaerobic ammonia oxidation coupled sludge as inoculum sludge, and using S... 2- S2O3 2- It acts as a sulfur-containing electron donor, with an operating time of 30–60 days. When the denitrification load is 1.88 kg N / (m³) 3 ·d)~2.26kgN / (m 3 ·d), the internal mass transfer rate of the particles is 0.03 kgN / (m). 3 ·d)~0.05kgN / (m 3 •d) When the abundance of filamentous bacteria is determined by molecular biology techniques or the length of filamentous material outside the sludge is measured by effective means, and the abundance of filamentous bacteria reaches 10%–50% or the length of filamentous material outside the sludge (FLA) is 10–50 μm, it is determined that filamentous bacteria overgrowth has occurred. At this time, hydroxylamine regulators and / or hydrazine regulators are continuously added to the reactor, and specific operating conditions of the reactor are controlled. After a period of time, the overgrowth of filamentous bacteria can be effectively controlled and the activity of anaerobic ammonia oxidizing bacteria can be enhanced.

[0018] This method utilizes hydroxylamine or hydrazine regulators, or a mixture of both, to specifically inhibit *Thiopyr* species. Thiothrix of SoxZ , fimAd Gene expression, the expression levels of SoxZ and fimAd increased from 1.72 × 10⁻⁶ to 1.72 × 10⁻⁶. 6 copies / gVSS ~ 1.82×10 6 copies / gVSS and 1.84×10 5 copies / gVSS ~ 1.94×10 5 Copies / gVSS decreased to 1.32×10 5 copies / gVSS ~ 1.42×10 5 copies / gVSS and 1.24×10 4 copies / gVSS ~ 1.34×10 4 copies / gVSS, but for other rod-shaped sulfur autotrophic denitrifying bacteria Thiobacillus, Sulfurimonas , SulfurovumThese regulators do not cause inhibition, thus achieving over-control of filamentous bacteria. They can also promote an increase in the activity of anaerobic ammonia-oxidizing bacteria from 120-150 mgTN / gVSS·d to 155-170 mgTN / gVSS·d, thereby increasing their contribution to total nitrogen removal.

[0019] Those skilled in the art generally believe that hydroxylamine and hydrazine can inhibit the activity of nitrifying bacteria (NOB) but have a weaker inhibitory effect on the activity of ammonia-oxidizing bacteria (AOB), thus using these regulators for the rapid achievement of short-cut nitrification. Alternatively, they are believed to promote the activity of anaerobic ammonia-oxidizing bacteria, and therefore used to improve the nitrogen removal performance of anaerobic ammonia oxidation systems. Or, hydroxylamine regulators are believed to promote the activity of nitrate reductase in sulfur-autotrophic denitrifying bacteria, thereby facilitating the accumulation of nitrite in sulfur-autotrophic processes. Hydroxylamine regulators, hydrazine regulators, or mixtures of both are generally not associated with the control of filamentous bacteria.

[0020] While hydroxylamine regulators, hydrazine regulators, or mixtures thereof can control the overgrowth of filamentous bacteria, inappropriate control conditions can lead to prolonged control periods or system disruption and collapse. This solution not only presents an innovative method for controlling overgrowth filamentous bacteria, but also demonstrates that adding regulators can maintain reactor pH at 8.3–8.7 and influent nitrogen loading at 3.50 kgN / (m³). 3 ·d)~3.77kgN / (m 3 •d), and the influent NaHCO3 concentration is 2.0g / L~5g / L, which can accelerate the control of overgrown filamentous bacteria. The effect is very significant. Using this technology, the control of overgrown filamentous bacteria can be achieved in about 10 days. There are currently no related reports.

[0021] When hydroxylamine regulators, hydrazine regulators, or a mixture of hydroxylamine and ammonia regulators are added, sulfur-autotrophic filamentous bacteria... SoxZ , fimAd Gene expression levels decreased significantly, and the abundance of sulfur-autotrophic filamentous bacteria decreased significantly. Sulfotrophic bacilli or vibrios with similar functions, such as... Thiobacillus, Sulfurimonas , Sulfurovum The abundance of these organisms increased significantly. Simultaneously, the activity of anaerobic ammonia-oxidizing bacteria was enhanced, and the mass transfer rate within the particles was effectively improved, thus ensuring the system's sulfur autotrophic denitrification (NO2) process. - -N accumulation) activity, anaerobic ammonia oxidation (NH4+) + -N and NO2 - The function of simultaneous removal of -N increases the total nitrogen removal load of the system and enhances the contribution rate of anaerobic ammonia oxidizing bacteria to total nitrogen removal.

[0022] In summary, by adding hydroxylamine regulators, hydrazine regulators, or a mixture of hydroxylamine and ammonia regulators, the excessive growth of filamentous bacteria in the sulfur autotrophic denitrification and anaerobic ammonia oxidation system can be effectively controlled, while increasing the contribution rate of anaerobic ammonia oxidation to total nitrogen removal.

[0023] The beneficial effects of this technical solution are as follows: (1) This solution provides a method that can simultaneously control the excessive growth of filamentous bacteria and improve the contribution rate of anaerobic ammonia oxidation to total nitrogen removal in a coupled system of sulfur autotrophic denitrification and anaerobic ammonia oxidation without changing the reactor operation mode, adding other external mechanical facilities or physical fields such as heat and electricity, or using strong oxidizing substances or metal cations. It has the advantages of being convenient to use, simple to operate, effective, and easy to apply in engineering.

[0024] (2) This scheme controls the overgrowth of sulfur filaments by specifically controlling the genus *Thiofilaria*. SoxZ , fimAd Gene expression levels, but for other sulfur-autotrophic bacteria Thiobacillus, Sulfurimonas , such as Thiothrix, SoxZ, fimAd, Thiobacillus, Sulfurimonas, Sulfurovum Gene expression is not affected, thus achieving specific control of the genus *Thiofilaria*.

[0025] (3) By using this scheme to control the overgrowth of filamentous bacteria, the activity of anaerobic ammonia oxidizing bacteria can be increased simultaneously (from 120-150 mg TN / g VSS·d to 155-170 mg TN / g VSS·d), and the ammonia nitrogen removal rate of anaerobic ammonia oxidizing bacteria can be increased (by 5% to 30%), thereby increasing the contribution rate of anaerobic ammonia oxidation to total nitrogen removal.

[0026] (4) By using this scheme to control the excessive growth of filamentous bacteria, the internal mass transfer rate of sludge particles can be increased from 0.03 kgN / (m³) 3 ·d)~0.05kgN / (m 3 ·d) increased to 0.12 kgN / (m 3 ·d)~0.15kgN / (m 3 •d) This avoids the lack of substrate inside the granules, which can affect the activity of microorganisms and even cause the granules to become hollow and disintegrate, effectively ensuring the denitrification rate of granular sludge (total nitrogen removal rate is stable at over 90%). Attached Figure Description

[0027] Figure 1 Graphs showing FLA levels before and after the addition of hydroxylamine modifiers; Figure 2 SEM images of sludge before and after the addition of hydroxylamine conditioner; (a) SEM image of sludge before hydroxylamine addition; (b) SEM image of sludge before hydroxylamine addition. Figure 3The abundance of filamentous bacteria and other non-filamentous sulfur-autotrophic denitrifying bacteria before and after the addition of hydroxylamine regulators; Figure 4 The changes in TN removal rate and contribution rate of anaerobic ammonia oxidation to total nitrogen removal before and after the addition of hydroxylamine regulators are shown in (a) TN removal rate before and after the addition of hydroxylamine, and (b) the change in contribution rate of anaerobic ammonia oxidation to total nitrogen removal. Detailed Implementation

[0028] The present invention will be further described in detail below with reference to the embodiments, but the embodiments of the present invention are not limited thereto. Unless otherwise specified, the technical means used in the following examples are conventional means well known to those skilled in the art: the materials, reagents, etc. used can all be obtained commercially.

[0029] Example 1: Using a UASB reactor, with the temperature controlled at 30℃ and the pH at 7.8, and under conditions where sulfur autotrophic denitrification sludge and anaerobic ammonium oxidation sludge coexist, the influent NH4... + -N and NO3 - When the -N concentrations are 150 mg N / L and 150 mg N / L respectively, when S 2- The concentration is 200 mg S / L, S 2- With NO3 - When the molar ratio was 0.43 and the influent NaHCO3 concentration was 3 g / L, filamentous bacteria overgrowth occurred, with an abundance of 15% and an extrafilamentous length (FLA) of 18 μm. -1 , By continuously adding 10 mg / L hydroxylamine hydrochloride, filamentous bacteria can be controlled. Thiothrix Effective control, genes SoxZ , fimAd The expression levels were 1.75 × 10⁻⁶. 6 copies / gVSS and 1.88×10 5 Copies / gVSS decreased to 1.35×10 5 copies / gVSS and 1.28×10 4 The number of copies / gVSS decreased by 90.2% for filamentous bacteria and by 60% for FLA. Thiobacillus , Thiothrix , Sulfurimonas , Sulfurovum and SulfuritaleaThe total abundance of isosulfate-autotrophic bacteria increased from 5.12% to 37.2%. The activity of anaerobic ammonia oxidizing bacteria increased significantly, from 137.25 mg TN / (g VSS·d) to 158.26 mg TN / (g VSS·d), with a TN removal rate increase of 5.8%, and the contribution of anaerobic ammonia oxidation to total nitrogen increasing from 50% to 62%. The addition of hydroxylamine not only controlled filamentous bacteria in the system but also improved anaerobic ammonia oxidation activity and its contribution to total nitrogen removal, thereby maintaining the system's long-term stable denitrification potential.

[0030] Example 2: In a UASB reactor, with the temperature controlled at 30℃ and the pH at 7.0, and under conditions where sulfur autotrophic denitrification sludge and anaerobic ammonium oxidation sludge coexist, the influent NH4+... + -N and NO3 - When the -N concentrations are 100 mg N / L and 60 mg N / L, respectively, when S2O3 2- The concentration is 150 mg S / L, S 2- With NO3 - When the molar ratio was 0.31 and the influent NaHCO3 concentration was 2 g / L, filamentous bacteria overgrowth, with an abundance of 10% and an external filamentous material length (FLA) of 10 μm. -1 , By continuously adding 5 mg / L hydroxylamine hydrochloride, filamentous bacteria can be controlled. Thiothrix Effective control, genes SoxZ , fimAd The expression levels were 1.72 × 10⁻⁶. 6 copies / gVSS and 1.84×10 5 Copies / gVSS decreased to 1.32×10 5 copies / gVSS and 1.24×10 4 copies / gVSS, filamentous abundance decreased by 89%, and FLA decreased by 55%. Thiobacillus , Thiothrix , Sulfurimonas , Sulfurovum and Sulfuritalea The total abundance of isosulfate autotrophic bacteria increased from 5.12% to 35.2%. The activity of anaerobic ammonia oxidizing bacteria increased significantly, from 120 mg TN / (g VSS d) to 155 mg TN / (g VSS d), the TN removal rate increased by 5%, and the contribution of anaerobic ammonia oxidation to total nitrogen increased from 50% to 60%.

[0031] Example 3: Using a UASB reactor, with a controlled temperature of 35℃ and pH of 8.7, and under conditions where sulfur autotrophic denitrification sludge and anaerobic ammonium oxidation sludge coexist, the influent NH4...+ -N and NO3 - When the -N concentrations are 250 mg N / L and 300 mg N / L, respectively, when S 2- The concentration is 300 mg S / L, S 2- With NO3 - When the molar ratio was 0.58 and the influent NaHCO3 concentration was 8 g / L, filamentous bacteria overgrowth, with an abundance of 50% and an external filamentous material length (FLA) of 50 μm. -1 , By continuously adding 50 mg / L hydroxylamine hydrochloride, filamentous bacteria can be controlled. Thiothrix Effective control, genes SoxZ , fimAd The expression levels were 1.82 × 10⁻⁶. 6 copies / gVSS and 1.94×10 5 Copies / gVSS decreased to 1.42 × 10⁻⁶ 5 copies / gVSS and 1.34×10 4 copies / gVSS, filamentous bacteria abundance decreased by 95%, and FLA decreased by 70%. Thiobacillus , Thiothrix , Sulfurimonas , Sulfurovum and Sulfuritalea The total abundance of isosulfate autotrophic bacteria increased from 5.12% to 40%. The activity of anaerobic ammonia oxidizing bacteria increased significantly, from 150 mg TN / (g VSSd) to 170 mg TN / (g VSS·d), the TN removal rate increased by 30%, and the contribution of anaerobic ammonia oxidation to total nitrogen increased from 50% to 80%.

[0032] Example 4: Using a UASB reactor, with a controlled temperature of 33℃ and pH of 8.3, and under conditions where sulfur autotrophic denitrification sludge and anaerobic ammonium oxidation sludge coexist, the influent NH4+... + -N and NO3 - When the -N concentrations are 150 mg N / L and 200 mg N / L, respectively, when S2O3 2- The concentration is 300 mg S / L, S 2- With NO3 - When the molar ratio was 0.50 and the influent NaHCO3 concentration was 5 g / L, filamentous bacteria overgrowth occurred, with an abundance of 30% and an extrafilamentous length (FLA) of 28 μm. -1 , By continuously adding 20 mg / L hydroxylamine hydrochloride, filamentous bacteria can be controlled. Thiothrix Effective control, genes SoxZ , fimAdThe expression levels were 1.78 × 10⁻⁶. 6 copies / gVSS and 1.91×10 5 Copies / gVSS decreased to 1.38 × 10⁻⁶ 5 copies / gVSS and 1.31×10 4 copies / gVSS decreased filamentous abundance by 91% and FLA decreased by 65%. Thiobacillus , Thiothrix , Sulfurimonas , Sulfurovum and Sulfuritalea The total abundance of isosulfate autotrophic bacteria increased from 5.12% to 38%. The activity of anaerobic ammonia oxidizing bacteria increased significantly, from 142 mg TN / (g VSSd) to 163 mg TN / (g VSS·d), the TN removal rate increased by 15%, and the contribution of anaerobic ammonia oxidation to total nitrogen increased from 50% to 70%.

Claims

1. A method for improving the nitrogen removal efficiency of a coupled sulfur autotrophic denitrification and anaerobic ammonia oxidation system, comprising the following steps: S1. When the denitrification load is limited and the mass transfer rate inside the particles decreases, the abundance of filamentous bacteria or the length of filamentous material outside the sludge can be measured by molecular biology techniques to determine whether filamentous bacteria are overgrown. When the abundance of filamentous bacteria reaches 10% to 50% or the length of filamentous material outside the sludge (FLA) is 10 to 50 μm, it can be determined that filamentous bacteria are overgrown. S2. Continuously add hydroxylamine regulators and / or hydrazine regulators into the reactor. The reactor can be run for 10-30 days.

2. The method according to claim 1, characterized in that, In S1, a sulfur autotrophic denitrification and anaerobic ammonia oxidation coupled system using reducing sulfur-containing compounds as sulfur-containing electron donors is employed. An anaerobic reactor is used, with a mixture of sulfur autotrophic denitrification sludge and anaerobic ammonia oxidation coupled sludge as inoculum sludge in a mass ratio of (0.5:1~2:1). The reactor influent is S2O3. 2- NO3 - and NH4 + When -N, S2O3 2- NO3 - and NH4 + -N concentrations were 150~300 mgS / L, 60 mgN / L~200 mgN / L, and 100 mgN / L~250 mgN / L, respectively; temperature was 30~35℃; pH was 7.0~8.7; influent NaHCO3 concentration was 2.0 g / L~8 g / L; HRT was 2 h~48 h; and operating time was 20~60 days. The reactor inlet water is S 2- NO3 - and NH4 + When -N, S 2- NO3 - and NH4 + -N concentrations of 200–300 mg / L, 100–300 mg / L, and 50–250 mg / L were used, with temperatures of 30–35 °C, pH values ​​of 7.0–8.7, influent NaHCO3 concentrations of 2.0 g / L–8 g / L, HRT of 2 h–48 h, and operating times of 20–60 days.

3. The method according to claim 1, characterized in that, In S1, when the denitrification load is limited, the decrease in the internal mass transfer rate of the particles refers to a total nitrogen removal load of 1.88 kgN / (m³). 3 ·d)~2.26kgN / (m 3 ·d), particle mass transfer rate 0.03 kgN / (m 3 ·d)~0.05kgN / (m 3 ·d); The total nitrogen removal load was significantly lower than the normal operating condition of 3.02 kgN / (m³). 3 ·d)~3.25kgN / (m 3 ·d) and particle mass transfer rate 0.12 kgN / (m 3 ·d)~0.15kgN / (m 3 ·d); In S1, the abundance of filamentous bacteria is determined by molecular biology techniques or the length of filamentous material outside the sludge is determined by effective means. The molecular biology techniques used can be based on high-throughput sequencing technology of 16S rRNA, or sequencing technology based on metagenomics, or methods based on quantitative PCR. The effective means adopted are based on fluorescence in situ hybridization (FISH) staining technology or observation technology based on electron microscopy.

4. The method according to claim 1, characterized in that, The concentration of hydroxylamine regulator in S2 is 5 mg / L to 50 mg / L, and the concentration of hydrazine regulator is 3 mg / L to 50 mg / L. When hydroxylamine regulator and hydrazine regulator are added at the same time, the mass ratio of the two is 1:5 to 5:1, more preferably 1:3 to 3:

1.

5. The method according to claim 1, characterized in that, In S2, the added hydroxylamine regulator is one or more of hydroxylamine hydrochloride, hydroxylamine sulfate, hydroxylamine phosphate, hydroxylamine formate, and hydroxylamine acetate; preferably, it is hydroxylamine hydrochloride. The added hydrazine-based regulator is one or more of hydrazine, hydrazine sulfate, hydrazine hydrate, methylhydrazine, and phenylhydrazine; preferably hydrazine and hydrazine hydrate.

6. The method according to claim 1, characterized in that, In S2, the reactor operating conditions are maintained as follows: temperature 30–35℃, pH 8.3–8.7, and influent nitrogen load 3.50 kgN / (m³). 3 ·d)~3.77kgN / (m 3 •d) The influent NaHCO3 concentration is 2.0 g / L to 5 g / L; the operating time is 15 to 25 days.

7. The method according to claim 1, characterized in that, In S2, achieving effective control of overgrown filamentous bacteria and enhancing the activity of anaerobic ammonia oxidizing bacteria means that the abundance of filamentous bacteria decreased by 15-95%, FLA decreased by 10-70%, and the total nitrogen removal rate increased by 5-30%.

8. The method according to claim 1, characterized in that, In S2, after the reactor operated for 10-30 days, the internal mass transfer rate of the sludge particles decreased from 0.03 kg N / (m³). 3 ·d)~0.05kgN / (m 3 ·d) increased to 0.12 kgN / (m 3 ·d)~0.15kgN / (m 3 The activity of anaerobic ammonia oxidizing bacteria increased from 120-150 mg TN / g VSS·d to 155-170 mg TN / g VSS·d, and the total nitrogen removal load increased to 3.02 kg N / (m³). 3 ·d)~3.25kgN / (m 3 ·d).

9. The method according to claim 1, characterized in that, Hydroxylamine regulators and / or hydrazine regulators specifically inhibit Thiothrix. SoxZ , fimAd Gene expression, the expression levels of SoxZ and fimAd increased from 1.72 × 10⁻⁶ to 1.72 × 10⁻⁶. 6 copies / gVSS ~ 1.82×10 6 copies / gVSS and 1.84×10 5 copies / gVSS ~ 1.94×10 5 Copies / gVSS decreased to 1.32 × 10⁻⁶ 5 copies / gVSS ~ 1.42×10 5 copies / gVSS and 1.24×10 4 copies / gVSS ~ 1.34×10 4 It has copies / gVSS, but does not inhibit other rod-shaped sulfur autotrophic denitrifying bacteria such as Thiobacillus, Sulfurimonas, and Sulfurovum.

10. The method according to claim 1, characterized in that, Stable operation phase S of the reactor 2- The removal rate reached over 99%, NO3 - The removal rate reached 93%, NH4 + The removal rate is greater than 85%, the total nitrogen removal rate is over 90%, and the contribution rate of anaerobic ammonia oxidation denitrification is consistently above 60%.

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