A method for rapidly restoring the denitrification efficiency of an anaerobic ammonium oxidation system

Abstract

The present invention provides a method for rapidly restoring the denitrification efficiency of an anaerobic ammonium oxidation system, aiming to solve the problem of insufficient activity of anaerobic ammonium oxidizing bacteria in a restricted reactor. By introducing high-activity anaerobic ammonium oxidizing bacteria in the side stream and adding 5-6 mg / L of Fe 3+ , while adjusting the hydraulic retention time, significantly improved the adaptability and denitrification rate of anaerobic ammonia oxidizing bacteria. Experiments showed that this method increased the denitrification rate from 40mg N / L / d to 160mg N / L / d, an increase of 300%. In addition, by laying hollow plastic balls with a diameter of 16mm in the reactor, a strict anaerobic environment was ensured, which was conducive to the recovery of the activity of anaerobic ammonia oxidizing bacteria. 3+ This method optimizes the microbial growth environment, enhances bacterial flora stability and denitrification efficiency, inhibits competition from harmful microorganisms, and is simple to operate and environmentally friendly. This invention not only significantly improves the overall efficiency of sewage treatment systems, but also reduces energy consumption and sludge production, lowering denitrification costs. It is suitable for all sewage treatment scenarios requiring efficient denitrification.

Description

Technical Field

[0001] The present invention belongs to the technical field of sewage treatment, and in particular relates to a method for rapidly recovering the denitrification efficiency of an anaerobic ammonium oxidation system. Technical Background

[0002] Anaerobic ammonium oxidation (Anammox) technology is the most efficient biological denitrification technology in recent years. Because of its advantages of high efficiency, economy and environmental protection, it is considered to be one of the most promising biological denitrification technologies. Anammox refers to the process by which anaerobic ammonium-oxidizing bacteria (AnAOB) convert ammonia nitrogen (NH4 + -N) as an electron donor, nitrite (NO2 - Anaerobic ammonium oxidation (ANAMMOX) is an electron acceptor that is directly converted into nitrogen gas under anoxic conditions, eliminating the denitrification process required in traditional denitrification technologies and eliminating the need for aeration and other steps. Compared to traditional nitrification-denitrification processes, ANAMMOX can reduce organic carbon source requirements by 100%, sludge production by 90%, and oxygen consumption by 60%, significantly reducing energy consumption and significantly lowering denitrification costs.

[0003] The denitrification rate of an ANAMMOX denitrification system hinges on the activity of ANAMMOX bacteria. When an ANAMMOX system is constrained, this is often accompanied by a significant decrease in ANAMMOX activity, resulting in a low denitrification rate and a difficulty in observing a clear upward trend over time. This phenomenon can be attributed to multiple factors, including but not limited to long-term starvation of ANAMMOX bacteria, resulting in a slow recovery rate, or a lack of ANAMMOX dominance in the ANAMMOX system.

[0004] To address these challenges and improve the denitrification rate of limited anaerobic ammonium oxidation systems, it is crucial to adopt effective strategies. Bioaugmentation, as an effective solution, has garnered significant attention. By introducing highly active anaerobic ammonium-oxidizing bacteria into the system, this technique can significantly increase the population density of these bacteria within a short period of time, thereby accelerating the denitrification process and improving overall efficiency. In this context, inoculation with highly active anaerobic ammonium-oxidizing bacteria has become a highly promising practical approach.

[0005] Sidestream ANAMMOX systems, with their unique growth environment, provide an ideal habitat for ANAMMOX bacteria. These systems typically maintain a suitable temperature range of 35-40°C, ensuring high ANAMMOX bacterial activity and achieving efficient denitrification. Numerous studies have demonstrated that ANAMMOX systems can exhibit high denitrification rates in sidestream environments. Therefore, using sidestream ANAMMOX bacteria as an inoculum source is undoubtedly a wise choice.

[0006] However, it is worth noting that anaerobic ammonium oxidizers, as autotrophic bacteria, have relatively weak adaptability to environmental changes and are extremely sensitive to environmental conditions. When highly active sidestream anaerobic ammonium oxidizers are inoculated into a restricted anaerobic ammonium oxidation system, although a significant increase in denitrification rate may be observed initially, this rate may then quickly decline due to environmental adaptability issues, returning to the low level before inoculation.

[0007] In view of the above situation, developing a method that can quickly activate the denitrification potential of the limited anaerobic ammonium oxidation system, ensure its short-term resumption of efficient operation, and ensure the long-term stable operation of the system and maintain a high level of denitrification efficiency is of vital importance to improving wastewater treatment efficiency. Summary of the Invention

[0008] In view of this, the purpose of the present invention is to provide a method for quickly restoring the denitrification efficiency of an anaerobic ammonium oxidation system, which aims to optimize the operating conditions of the anaerobic ammonium oxidation system, especially by introducing high-activity anaerobic ammonium oxidizing bacteria in the side stream and accurately controlling Fe 3+ concentration, quickly recover and significantly improve the denitrification efficiency of the restricted reactor, while ensuring long-term stable and efficient operation, thereby improving the overall efficiency and environmental friendliness of sewage treatment.

[0009] Specifically, the present invention provides a method for rapidly restoring the denitrification efficiency of an anaerobic ammonium oxidation system, comprising the following steps:

[0010] S1, add side stream anaerobic ammonium oxidation activated sludge to the reactor, and add Fe 3+ , in the following stage, Fe 3+ Keep adding and control the hydraulic retention time ≥14h;

[0011] S2. When the ammonia nitrogen effluent concentration of the reactor is stable below 5 mg / L and maintained for T1 day, shorten the hydraulic retention time to 9-10 hours;

[0012] S3. After shortening the hydraulic retention time in step S2, the ammonia nitrogen concentration in the reactor effluent will fluctuate. After waiting for the ammonia nitrogen effluent concentration to continue to stabilize below 5 mg / L and maintain for T2 days, the hydraulic retention time is further shortened to 7 hours. After that, the ammonia nitrogen concentration in the reactor effluent will fluctuate. After waiting for the anaerobic ammonia-oxidizing bacteria to adapt to the environment, the subsequent ammonia nitrogen effluent concentration will continue to stabilize below 5 mg / L and maintain for T3 days, indicating that the adjustment of the hydraulic retention time is successful.

[0013] In some specific embodiments of the present invention, the following step is further included: adding hollow balls into the reactor so that a layer of hollow balls floats above the liquid surface in the reactor.

[0014] In some specific embodiments of the present invention, the hollow ball is made of plastic, and the diameter of the hollow ball is 10-25 mm.

[0015] In some specific embodiments of the present invention, Fe is added to the influent. 3+ The content is 5-6mg / L.

[0016] In some specific embodiments of the present invention, Fe is added to the influent. 3+ The content is 6mg / L.

[0017] In some specific embodiments of the present invention, the Fe 3+ It is FeCl3.

[0018] In some specific embodiments of the present invention, the hydraulic retention time in step S2 is shortened to 9.33 h.

[0019] In some specific embodiments of the present invention, the hydraulic retention time in step S3 is shortened to 9.33 h.

[0020] In some specific embodiments of the present invention, T1=14, T2=14, and T3=30.

[0021] In some specific embodiments of the present invention, the reactor is a sequencing batch reactor (SBR).

[0022] In some specific embodiments of the present invention, the side stream anaerobic ammonium oxidation activated sludge added to the reactor comes from the sludge return flow of the side stream reactor in the side stream anaerobic ammonium oxidation system.

[0023] The side stream anaerobic ammonium oxidation system refers to a treatment system specifically used to promote the anaerobic ammonium oxidation (Anammox) process, and the side stream reactor is a part of the system, which is specially designed to maintain the growth environment of highly active anaerobic ammonium oxidizing bacteria.

[0024] In some specific embodiments of the present invention, the side stream anaerobic ammonium oxidation activated sludge added to the reactor is prepared by culturing under the following conditions: the reactor for culturing the side stream anaerobic ammonium oxidation activated sludge is an SBR reactor, the operating environment is an influent ammonia nitrogen concentration of 500-600 mg / L, a hydraulic retention time of 12h, an operating pH of 7.5, a temperature of 35°C, dissolved oxygen less than 0.5mg / L, and an effluent ammonia nitrogen concentration stably less than 20mg / L.

[0025] In some specific embodiments of the present invention, the particle size of the side-stream anaerobic ammonium oxidation activated sludge is 1-4 mm.

[0026] The present invention has the following significant advantages and effects compared to the prior art:

[0027] 1. Significantly improve denitrification efficiency: inoculate high-activity anaerobic ammonia-oxidizing bacteria from the side stream into the mainstream reactor and add Fe 3+ and adjusting the hydraulic retention time of the reactor, effectively improving the denitrification efficiency of the reactor.

[0028] 2. Optimize Fe 3+ Concentration control: Precisely control Fe 3+ The concentration was increased to 6 mg / L, which not only avoided the problem of unsatisfactory activity recovery caused by too low a concentration, but also prevented the inhibitory effect that might be caused by too high a concentration. At this concentration, the activity of anaerobic ammonia-oxidizing bacteria was significantly improved.

[0029] 3. Promote the recovery of anaerobic ammonia-oxidizing bacteria activity: By sealing the top of the reactor and laying hollow plastic balls to isolate oxygen, the anaerobic state of the reactor is achieved, which helps to restore the activity of anaerobic ammonia-oxidizing bacteria.

[0030] 4. Enhance bacterial flora stability: Fe 3+ It improves the growth environment of anaerobic ammonia-oxidizing bacteria, enhances their stability and activity in biofilm or suspended systems, and helps maintain long-term stable treatment effects.

[0031] 5. Inhibit harmful microorganisms: Fe 3+ It has a certain antibacterial effect and can inhibit the growth of competitive or harmful microorganisms, creating more favorable living conditions for anaerobic ammonia-oxidizing bacteria.

[0032] 6. Environmentally friendly: Fe 3+ As a relatively environmentally friendly substance, it will not introduce new harmful substances, has little impact on the environment, and meets environmental protection requirements.

[0033] In summary, the method for rapidly restoring the denitrification efficiency of an anaerobic ammonium oxidation system provided by the present invention effectively improves the activity, denitrification rate and overall treatment efficiency of anaerobic ammonium oxidizing bacteria, while enhancing the stability of the bacterial community and inhibiting the growth of harmful microorganisms. It is easy to operate, environmentally friendly, and has significant technical effects and application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Attachment Figure 1 This is a photo of the side-stream anaerobic ammonium oxidation activated sludge used in Examples 2-3 of the present invention.

[0035] Attachment Figure 2 This is a graph of ammonia nitrogen monitoring data in the SBR reactor in Example 2 of the present invention.

[0036] Attachment Figure 3 This is a graph showing monitoring data of nitrite nitrogen in the SBR reactor in Example 2 of the present invention.

[0037] Attachment Figure 4This is a graph showing nitric nitrogen monitoring data in the SBR reactor in Example 2 of the present invention.

[0038] Attachment Figure 5 is the ΔNO2 during the experiment in the SBR reactor in Example 2 of the present invention - -N / ΔNH4 + -N and ΔNO3 - -N / ΔNH4 + -N reaction stoichiometric ratio monitoring data diagram.

[0039] Attachment Figure 6 This is a graph of ammonia nitrogen monitoring data in the SBR reactor in Example 3 of the present invention.

[0040] Attachment Figure 7 This is a graph showing monitoring data of nitrite nitrogen in the SBR reactor in Example 3 of the present invention.

[0041] Attachment Figure 8 This is a graph showing nitric nitrogen monitoring data in the SBR reactor in Example 3 of the present invention.

[0042] Attachment Figure 9 is the ΔNO2 during the experiment in the SBR reactor in Example 3 of the present invention - -N / ΔNH4 + -N and ΔNO3 - -N / ΔNH4 + -N reaction stoichiometric ratio monitoring data diagram. DETAILED DESCRIPTION

[0043] Below in conjunction with specific embodiment, further set forth the present invention.Should be understood that these embodiments are only used to illustrate the present invention and are not used in limiting the scope of the present invention.In addition, should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms fall within the scope limited by the application equally.

[0044] Example 1 Method for Rapidly Restoring the Denitrification Efficiency of an Anaerobic Ammonium Oxidation System

[0045] A method for rapidly restoring the denitrification efficiency of an anaerobic ammonium oxidation system comprises the following steps:

[0046] S1. Adding side stream anaerobic ammonium oxidation activated sludge into a sequencing batch type SBR reactor, adding hollow plastic balls with a diameter of 16 mm into the sequencing batch type SBR reactor so that a layer of hollow plastic balls floats above the liquid surface of the sequencing batch type SBR reactor; at the same time, adding FeCl3 reagent to the influent to ensure that the FeCl3 content in the influent is 6 mg / L, and FeCl3 is always added in the subsequent stage to control the hydraulic retention time to be ≥14h; wherein, the side stream anaerobic ammonium oxidation activated sludge added to the sequencing batch type SBR reactor is prepared by culturing under the following conditions: the reactor for culturing the side stream anaerobic ammonium oxidation activated sludge is an SBR reactor, the operating environment is an influent ammonia nitrogen concentration of 500-600 mg / L, a hydraulic retention time of 12h, an operating pH of 7.5, a temperature of 35°C, dissolved oxygen less than 0.5mg / L, an effluent ammonia nitrogen concentration stably less than 20mg / L, and the particle size of the side stream anaerobic ammonium oxidation activated sludge is 1-4mm.

[0047] S2. When the ammonia nitrogen effluent concentration of the sequencing batch reactor is stable below 5 mg / L and maintained for 14 days, shorten the hydraulic retention time to 9.33 h;

[0048] S3. After shortening the hydraulic retention time in step S2, the ammonia nitrogen concentration in the effluent of the sequencing batch reactor will fluctuate. After waiting for the ammonia nitrogen effluent concentration to continue to stabilize below 5 mg / L and maintain for 14 days, the hydraulic retention time is further shortened to 7 hours. After that, the ammonia nitrogen concentration in the effluent of the sequencing batch reactor will fluctuate. After waiting for the anaerobic ammonia-oxidizing bacteria to adapt to the environment, the subsequent ammonia nitrogen effluent concentration will continue to stabilize below 5 mg / L and maintain for 30 days, indicating that the adjustment of the hydraulic retention time is successful.

[0049] Example 2 Testing of a method for rapidly restoring the denitrification efficiency of an anaerobic ammonium oxidation system

[0050] A 5-liter SBR reactor was constructed from a transparent acrylic cylinder with an inner diameter of 12 cm, an outer diameter of 13 cm, and a height of 40 cm, resulting in an effective volume of 3.5 L. The SBR reactor operated in an intermittent water inlet cycle, following a sequence of water inlet and stirring, settling, water outlet, and settling. The inlet flow rate was 15 ml / min for 100 minutes, and the stirring speed was 200 rpm. After stirring, the reactor was allowed to settle for 20 minutes. The outlet flow rate was 75 ml / min for 20 minutes, followed by a 10-minute settling period before the next cycle began. The stirring time was variable and varied according to the hydraulic retention time (HRT): 5.17 hours for a 14-hour HRT, 3.17 hours for a 9.3-hour HRT, and 2.17 hours for a 7-hour HRT. The SBR reactor was located indoors, where the temperature varied with room temperature, ranging from 25 to 30°C during the experiment. Fifty 16mm diameter hollow plastic balls were placed in the SBR reactor, floating above the liquid surface to isolate air. The reactor was sealed to isolate oxygen, leaving a small opening for sampling. Throughout the experiment, the influent pH was adjusted to 7.1-7.3 using 1 mol / L HCl. The influent matrix contained the following components and concentrations:

[0051] KH2PO4 0.028g·L -1 , CaCl2·2H2O 0.185g·L -1 , NaHCO3 1.68g·L -1 ,MgSO4.7H2O0.2g·L -1 , NH4 + -N80 mg·L -1 , NO2 - -N100 mg·L -1 , trace element solution Ⅰ 1ml·L -1 , trace element solution Ⅱ 1ml·L -1 .

[0052] Trace element solution I includes: EDTA 5g / L, FeSO4·7H2O 5g / L

[0053] Trace element solution II includes: EDTA 15g / L, H3BO3 0.011g / L, MnCl2·4H2O 0.99g / L, CuSO4·5H2O 0.25g / L, ZnSO4·7H2O 0.43g / L, NiCI2·6H2O 0.19g / L, (NH4)6Mo7O 24 ·4H2O0.16g / L, CoCl2·6H2O 0.24g / L, Na2SeO3·5H2O 0.1596g / L

[0054] The reactor was operated according to the hydraulic retention time in Table 1.

[0055] Table 1

[0056]

[0057] During the denitrification rate-limiting phase, the reactor was inoculated with flocculent ANAMMOX sludge in a long-term starvation state, with a sludge concentration of approximately 13,700 mg TSS / L. To increase the denitrification rate, the reactor was inoculated with sidestream ANAMMOX activated sludge. 500 ml of concentrated sidestream ANAMMOX activated sludge (TSS approximately 25,000 mg / L, SV30 ≥ 90) was inoculated into the reactor. After inoculation, the sludge concentration in the reactor was approximately 15,485 mg TSS / L. This means that the volume ratio of the inoculated sidestream ANAMMOX activated sludge to the sludge in the reactor was approximately 1:7.7.

[0058] Side-stream anaerobic ammonium oxidation activated sludge: The reactor for cultivating the side-stream anaerobic ammonium oxidation activated sludge in this experiment is an SBR reactor. The operating environment is an influent ammonia nitrogen concentration of 500-600 mg / L, a hydraulic retention time of 12 h, an operating pH of 7.5, a temperature of 35 ° C, and dissolved oxygen less than 0.5 mg / L. In the environment, the effluent ammonia nitrogen concentration is stable at less than 20 mg / L, and the anaerobic ammonium oxidation sludge particle size is 1-4 mm. Figure 1 The sludge in this reactor can be considered as the side stream anaerobic ammonium oxidation activated sludge inoculated in this experiment.

[0059] Water samples were filtered through a 0.45 μm water filter, and ammonia nitrogen was determined using the Nanoscale colorimetric method, nitrite nitrogen using N-(1-naphthyl)-ethylenediamine spectrophotometry, and nitric nitrogen using ultraviolet spectrophotometry. MLSS and TSS were analyzed using standard methods, and pH and dissolved oxygen were measured using a pH meter and a dissolved oxygen meter.

[0060] The hydraulic retention time (HRT), nitrogen removal rate (NRR), and nitrogen removal efficiency (NRE) mentioned in the article are calculated using the following formulas:

[0061] HRT=V / Q (1)

[0062] In formula (1), V represents the effective volume of the reactor (L), and Q represents the daily water inflow (L / d).

[0063] NRR=ΔC N / HRT (2)

[0064] In formula (2), ΔC Nrepresents the difference in the concentration of substances in the inlet and outlet water (mg / L), and HRT represents the hydraulic retention time (d).

[0065] NRE=ΔC N / C inf ×100% (3)

[0066] In formula (3), ΔC N Represents the difference in concentration of inlet and outlet water substances (mg / L), C inf The experimental results of the influent substance concentration (mg / L):

[0067] The inlet and outlet concentrations of ammonia nitrogen, nitrite nitrogen, and nitric nitrogen in the SBR reactor, nitrogen removal rate, and ΔNO2 during the experiment - -N / ΔNH4 + -N and ΔNO3 - -N / ΔNH4 + The stoichiometric ratios of the reactions of -N are as shown in the attached Figure 2-5 shown.

[0068] The reactor was first inoculated with anaerobic ammonium-oxidizing bacteria, whose denitrification efficiency was compromised by long-term starvation (permanently stored in sealed plastic barrels with room temperature fluctuations). After 20 days of incubation, the denitrification efficiency (NRE) was only 12.5±2.5%, and the denitrification rate (NRR) was 18±3 mg N L⁻¹ d⁻¹. To rapidly improve the system's denitrification efficiency, the reactor was inoculated with sidestream anaerobic ammonium-oxidizing activated sludge on day 20. To accelerate acclimatization and prevent the inhibitory effects of temperature and influent substrate concentration on the sidestream anaerobic ammonium-oxidizing activated sludge, 6 mg / L of FeCl₃ was added to the influent to enhance the sidestream anaerobic ammonium-oxidizing activated sludge's resistance to environmental fluctuations. FeCl₃ was continuously added throughout the experiment. From day 20 to 40 of the experiment, bioaugmentation significantly improved the system's denitrification efficiency, with near-complete removal of both ammonia and nitrite nitrogen in the effluent between 0 and 3 mg / L, and an NRE ≥ 95%. To ensure acclimatization of the sidestream anammox activated sludge to the environment, the hydraulic retention time (HRT) was not adjusted at this stage, resulting in an NRR of 127 ± 3 mg N L⁻¹ d⁻¹. Over the next 40-60 days, the HRT was adjusted from 14 h to 9.33 h. During the 7 days following the adjustment, effluent ammonia and nitrite concentrations fluctuated, reaching a peak of 23.63 mg / L on day 42 before returning to normal. This suggests that shortening the HRT had a moderate impact on the microbial community within the system. The subsequent return to normal suggests a degree of resilience to environmental changes, and that the HRT adjustment also enhanced its resistance to environmental perturbations. At this point, the NRR within the system stabilized at 204 ± 6 mg N L⁻¹ d⁻¹, with effluent ammonia and nitrite concentrations approaching zero and an NRE ≥ 95%. After the effluent ammonia nitrogen concentration stabilized at less than 5 mg / L for two weeks, the hydraulic retention time was further shortened to 7 hours. After the adjustment, the fluctuation period of the effluent ammonia nitrogen concentration was longer than the previous stage, lasting 60-85 days, and the highest effluent ammonia nitrogen concentration reached 40.15 mg / L, then slowly decreased until it finally stabilized at 2±2 mg / L. The longer fluctuation period of effluent ammonia nitrogen indicates that the adjustment of the hydraulic retention time has a greater impact on the stability of the system, requiring a longer period of adaptation and recovery. However, the effluent ammonia nitrogen concentration was finally able to stabilize below 5 mg / L, indicating that this adjustment was still within the tolerance range of the system. After the adjustment and stabilization, the system's NRR reached 260±10 mg N L-1d-1.

[0069] The above results show that by inoculating side stream anaerobic ammonium oxidation activated sludge in the anaerobic ammonium oxidation system with limited denitrification rate, adding 6 mg / L FeCl3 to the influent and adjusting the hydraulic retention time, the system can achieve a higher denitrification rate.

[0070] The change of the stoichiometric ratio of the anaerobic ammonium oxidation reaction can well reflect the operating status of the system. In theory, ΔNO2 - -N / ΔNH4 + -N(R1) ratio is 1.32, ΔNO3 - -N / ΔNH4 + The ratio of -N(R2) is 0.26. During the period of 0-20 days, due to the damage of the denitrification performance of anaerobic ammonium oxidizing bacteria caused by long-term starvation, R1 and R2 fluctuated greatly and did not conform to the theoretical values, indicating that the system was in a disordered state at this stage. 3+ Afterwards, a stable anaerobic ammonium oxidation reaction could be clearly observed. Except for a small fluctuation when adjusting the hydraulic retention time, the ratios of R1 and R2 had stabilized at 1.32±0.2 and 0.26±0.1, respectively, by the end of the experiment, indicating that the anaerobic ammonium oxidation reaction was in a stable state at this time.

[0071] Example 3 Comparative Test of Methods for Rapidly Restoring Denitrification Efficiency of Anaerobic Ammonium Oxidation Systems

[0072] In this example, only the side stream anaerobic ammonium oxidation activated sludge was added on the 20th day, and no FeCl3 was added to the influent. The other operations were consistent with those in Example 2. The inlet and outlet concentrations of ammonia nitrogen, nitrite nitrogen, and nitrate nitrogen in the SBR reactor, the nitrogen removal rate, and ΔNO2 during the experiment - -N / ΔNH4 + -N and ΔNO3 - -N / ΔNH4 + The stoichiometric ratio of the reaction of -N is shown in the attached Figure 6-9 shown.

[0073] On day 20 of the experiment, after inoculation with sidestream ANAMMOX activated sludge, the effluent ammonia nitrogen concentration rapidly dropped to 3±3 mg / L. However, starting on day 29, the effluent ammonia nitrogen concentration rebounded, reaching a final concentration of 53±2 mg / L after two adjustment cycles. The NRE was 36±2%, and the NRR was 100±10 mg N L⁻¹d⁻¹. This indicates that inoculation of only sidestream ANAMMOX activated sludge into the reactor exhibited high activity only during the first nine days of inoculation due to its poor resistance to environmental fluctuations. However, with increasing environmental stress, the activity of the sidestream ANAMMOX activated sludge gradually declined. The final effluent ammonia nitrogen concentration was approximately 50 mg / L higher than that of the previous experiment, while the NRR was only approximately one-third of that observed in the previous experiment. This indicates that 6 mg / L of FeCl⁺ significantly improved the environmental resistance of sidestream ANAMMOX activated sludge.

[0074] Although the present invention has been described using the above embodiments, it should be understood that the present invention may be further modified and varied without departing from the spirit of the present invention, and these modifications and variations are all within the scope of protection of the present invention.

Claims

1. A method for rapidly restoring the denitrification efficiency of an anaerobic ammonium oxidation system, characterized in that: The following steps are involved: S1, add side stream anaerobic ammonium oxidation activated sludge to the reactor, and add Fe 3+ , in the following stage, Fe 3+ Keep adding and control the hydraulic retention time ≥14 h; add Fe 3+ The content is 5-6 mg / L; S2. When the ammonia nitrogen effluent concentration of the reactor is stable below 5 mg / L and maintained for T1 day, shorten the hydraulic retention time to 9-10 hours; After shortening the hydraulic retention time in steps S3 and S2, the ammonia nitrogen concentration in the reactor effluent will fluctuate. Wait for the ammonia nitrogen effluent concentration to continue to stabilize below 5 mg / L and maintain it for T2 days, then further shorten the hydraulic retention time to 7 hours. After that, the ammonia nitrogen concentration in the reactor effluent will fluctuate. Wait for the anaerobic ammonia-oxidizing bacteria to adapt to the environment. The subsequent ammonia nitrogen effluent concentration will continue to stabilize below 5 mg / L and maintain it for T3 days, indicating that the adjustment of the hydraulic retention time is successful.

2. The method for rapidly recovering the denitrification efficiency of an anaerobic ammonium oxidation system according to claim 1, characterized in that: The method also includes the following steps: adding hollow balls into the reactor so that a layer of hollow balls floats above the liquid surface of the reactor.

3. The method for rapidly recovering the denitrification efficiency of an anaerobic ammonium oxidation system according to claim 2, characterized in that: The hollow balls are made of plastic and have a diameter of 10-25 mm.

4. The method for rapidly recovering the denitrification efficiency of an anaerobic ammonium oxidation system according to claim 1, characterized in that: The Fe 3+ It is FeCl3.

5. The method for rapidly recovering the denitrification efficiency of an anaerobic ammonium oxidation system according to claim 1, characterized in that: Said T1=14, T2=14, T3=30.

6. The method for rapidly recovering the denitrification efficiency of an anaerobic ammonium oxidation system according to claim 1, characterized in that: The reactor is a sequencing batch type SBR reactor.

7. The method for rapidly recovering the denitrification efficiency of an anaerobic ammonium oxidation system according to any one of claims 1 to 6, characterized in that: The side stream anaerobic ammonium oxidation activated sludge added to the reactor comes from the sludge return flow of the side stream reactor in the side stream anaerobic ammonium oxidation system.

8. The method for rapidly recovering the denitrification efficiency of an anaerobic ammonium oxidation system according to any one of claims 1 to 6, characterized in that: The side stream anaerobic ammonium oxidation activated sludge added to the reactor is prepared by culturing under the following conditions: the reactor for culturing the side stream anaerobic ammonium oxidation activated sludge is an SBR reactor, the operating environment is an influent ammonia nitrogen concentration of 500-600 mg / L, a hydraulic retention time of 12 h, an operating pH of 7.5, a temperature of 35°C, dissolved oxygen less than 0.5 mg / L, and an effluent ammonia nitrogen concentration is stably less than 20 mg / L.

9. The method for rapidly recovering the denitrification efficiency of an anaerobic ammonium oxidation system according to claim 8, characterized in that: The particle size of the side-stream anaerobic ammonium oxidation activated sludge is 1-4 mm.

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