Method for rapidly recovering denitrification efficiency of anaerobic ammonia oxidation system

Abstract

The invention provides a method for rapidly recovering denitrification efficiency of an anaerobic ammonium oxidation system, and aims to solve the problem of insufficient activity of anaerobic ammonium oxidation bacteria in a limited reactor. The lateral flow high-activity anaerobic ammonium oxidation bacteria are introduced, 5-6 mg / L of Fe < 3 + > is added into the inlet water, and meanwhile, the hydraulic retention time is adjusted, so that the adaptability and denitrification rate of the anaerobic ammonium oxidation bacteria are remarkably improved. Experiments show that the method increases the denitrification rate from 40mg N / L / d to 160mg N / L / d, and the amplification reaches 300%. Besides, hollow plastic small balls with the diameter of 16mm are laid in the reactor, so that a strict anaerobic environment is ensured, and the activity recovery of anaerobic ammonium oxidation bacteria is facilitated. The Fe < 3 + > optimizes the growth environment of microorganisms, enhances the flora stability and the denitrification efficiency, inhibits the competition of harmful microorganisms, and is simple to operate and environment-friendly. The overall efficiency of the sewage treatment system is greatly improved, the energy consumption and the sludge yield are reduced, the denitrification cost is reduced, and the system is suitable for various sewage treatment scenes with efficient denitrification requirements.

Description

Technical Field

[0001] The 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 efficient denitrification, 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 - -N) is an electron acceptor and is directly converted into nitrogen under anoxic conditions, eliminating the denitrification process in traditional denitrification technology, and thus eliminating the need for aeration and other steps. Compared with traditional nitrification-denitrification processes, the anaerobic ammonium oxidation process can reduce 100% of the demand for organic carbon sources, 90% of sludge production, and 60% of oxygen consumption, significantly reducing energy consumption and greatly reducing denitrification costs.

[0003] The core of the denitrification rate of the anaerobic ammonium oxidation denitrification system lies in the activity state of anaerobic ammonium oxidizing bacteria (Anammoxbacteria). When the anaerobic ammonium oxidation system is limited, it is often accompanied by a significant decrease in the activity of anaerobic ammonium oxidizing bacteria, resulting in a low denitrification rate, and it is difficult to observe a clear upward trend over time. The occurrence of this phenomenon can be attributed to multiple factors, including but not limited to the long-term starvation of anaerobic ammonium oxidizing bacteria resulting in a slow recovery rate or the anaerobic ammonium oxidizing bacteria not being dominant in the anaerobic ammonium oxidation system.

[0004] In order to meet the above challenges and improve the denitrification rate of limited anaerobic ammonium oxidation systems, it is particularly important to adopt effective strategies. Among them, bioaugmentation technology has attracted much attention as an effective solution. By introducing highly active anaerobic ammonium oxidizing bacteria into the system, this technology can significantly increase the population density of anaerobic ammonium oxidizing bacteria in the system in a short period of time, thereby accelerating the denitrification process and improving the overall efficiency. In this context, inoculation with highly active anaerobic ammonium oxidizing bacteria has become a very promising practical method.

[0005] The side-flow anammox system, with its unique growth environment advantages, provides an ideal habitat for anammox bacteria. The system is usually maintained in a suitable temperature range of 35-40°C, ensuring the high activity of anammox bacteria, thereby achieving efficient denitrification performance. Numerous studies have fully confirmed that in a side-flow environment, the anammox system can exhibit a high denitrification rate. Therefore, it is undoubtedly a wise choice to use side-flow anammox bacteria as an inoculation source.

[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 side-flow anaerobic ammonium oxidizers are inoculated into a restricted anaerobic ammonium oxidation system, although a significant increase in the denitrification rate may be observed in the early stages, the denitrification rate may then drop rapidly due to environmental adaptability issues and return 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 and ensure its restoration of efficient operation in the short term, while ensuring the long-term stable operation of the system and maintaining 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 object 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 side stream highly active anaerobic ammonium oxidizing bacteria and accurately controlling Fe 3+ concentration, quickly restore 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 quickly 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 stabilized below 5 mg / L and maintained for T1 day, shorten the hydraulic retention time to 9-10 h;

[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 of 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, the influent is added with Fe 3+ The content is 5-6mg / L.

[0016] In some specific embodiments of the present invention, the influent is added with Fe 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 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.

[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] Compared with the prior art, the present invention has the following significant advantages and effects:

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

[0028] 2. Optimize Fe 3+ Concentration control: Precise control of Fe 3+ The concentration reached 6 mg / L, which not only avoided the problem of unsatisfactory activity recovery caused by too low concentration, but also prevented the inhibitory effect that might be caused by too high 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 recovering 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 flora 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] Attached 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] Attached Figure 2 This is a graph of ammonia nitrogen monitoring data in the SBR reactor in Example 2 of the present invention.

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

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

[0038] Attached 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] Attached Figure 6 This is a graph of ammonia nitrogen monitoring data in the SBR reactor in Example 3 of the present invention.

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

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

[0042] Attached Fig. 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] The present invention will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention. In addition, it 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; adding FeCl3 reagent into the influent to ensure that the content of FeCl3 in the influent is 6 mg / L, and FeCl3 is added continuously in the subsequent stage to control the hydraulic retention time to be ≥14 h; wherein, the side stream anaerobic ammonium oxidation activated sludge added into 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 12 h, an operating pH of 7.5, a temperature of 35°C, dissolved oxygen less than 0.5 mg / L, an effluent ammonia nitrogen concentration of less than 20 mg / L, and a particle size of the side stream anaerobic ammonium oxidation activated sludge of 1-4 mm.

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

[0048] S3. After shortening the hydraulic retention time in step S2, the effluent ammonia nitrogen concentration of the sequencing batch reactor will fluctuate. After waiting for the effluent ammonia nitrogen 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 effluent ammonia nitrogen concentration of the sequencing batch reactor will fluctuate. After waiting for the anaerobic ammonia-oxidizing bacteria to adapt to the environment, the subsequent effluent ammonia nitrogen 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] 1 SBR reactor device is made of a transparent acrylic cylinder with a volume of 5L, an inner diameter of 12cm, an outer diameter of 13cm, a height of 40cm, and an effective volume of 3.5L. The SBR reactor adopts an intermittent water inlet mode, and operates according to the step cycle of water inlet and stirring-still settling-water outlet-stilling. The water inlet flow rate is 15ml / min, which lasts for 100min, the speed during stirring is 200r / min, and it is left to stand for 20min after stirring. The water outlet flow rate is 75ml / min, which lasts for 20min, and then it is left to stand for 10min before continuing the next cycle. The stirring time is not fixed, and it changes accordingly according to different hydraulic retention times: when the hydraulic retention time is 14h, the stirring time is 5.17h; when the hydraulic retention time is 9.3h, the stirring time is 3.17h; when the hydraulic retention time is 7h, the stirring time is 2.17h. The SBR reactor is placed indoors, and the temperature changes with the room temperature. The temperature during the experiment is 25-30℃. 50 plastic hollow balls with a diameter of 16 mm were placed in the SBR reactor and floated above the liquid surface to isolate the air. The SBR reactor was sealed to isolate oxygen, leaving a small cover for sample testing. During the entire experiment, the pH of the influent was adjusted to 7.1-7.3 using 1 mol / L HCl. The influent matrix contained the following components and contents:

[0051] KH2PO4 0.028g·L -1 , CaCl2·2H2O 0.185g·L -1 , NaHCO3 1.68 g·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] The sludge inoculated in the reactor during the denitrification rate-limited stage is flocculent anaerobic ammonium oxidation sludge under long-term starvation, and the sludge concentration is about 13700mg TSS / L. In order to improve the denitrification rate of the reactor, the sludge inoculated is the side-stream anaerobic ammonium oxidation activated sludge. 500ml of concentrated side-stream anaerobic ammonium oxidation activated sludge (TSS is about 25000mg / L, sv30≥90) is inoculated into the reactor. After inoculation, the sludge concentration in the reactor is about 15485mg TSS / L. That is, the volume ratio of the inoculated side-stream anaerobic ammonium oxidation activated sludge to the sludge in the reactor is about 1:7.7.

[0058] Sidestream anaerobic ammonium oxidation activated sludge: The reactor for cultivating the sidestream anaerobic ammonium oxidation activated sludge inoculated 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 a dissolved oxygen of less than 0.5 mg / L. In the environment, the effluent ammonia nitrogen concentration is stable at less than 20 mg / L, and the particle size of the anaerobic ammonium oxidation sludge 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] The effluent samples were filtered through a 0.45 μm water filter, and ammonia nitrogen was determined by the nanometer reagent colorimetric method, nitrite nitrogen was determined by N-(1-naphthyl)-ethylenediamine spectrophotometry, and nitric nitrogen was determined by ultraviolet spectrophotometry. MLSS and TSS were analyzed using standard methods, and pH and dissolved oxygen were determined 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 inlet and outlet substances (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 the concentration of inlet and outlet water substances (mg / L), C inf The experimental results of 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 are as shown in the attached Figure 2-5 shown.

[0068] The reactor was first inoculated with anaerobic ammonium-oxidizing bacteria whose denitrification effect was impaired under long-term starvation conditions (placed in a sealed plastic barrel for a long time, and the temperature changed with room temperature). After 20 days of cultivation, the denitrification efficiency (NRE) was only 12.5±2.5%, and the denitrification rate (NRR) was 18±3mg N L-1d-1. In order to quickly improve the denitrification effect of the system, the side-stream anaerobic ammonium-oxidizing activated sludge was inoculated into the reactor on the 20th day. At the same time, in order to make it quickly adapt to the environment and avoid the fluctuations of temperature and influent substrate concentration on the activity of the side-stream anaerobic ammonium-oxidizing activated sludge, it was found that 6mg / L of FeCl3 was added to the influent at the same time to enhance the resistance of the side-stream anaerobic ammonium-oxidizing activated sludge to environmental fluctuations. FeCl3 was added in the subsequent stages. On the 20th to 40th day of the experiment, after bio-augmentation, it was observed that the denitrification effect of the system was significantly improved, and the effluent ammonia nitrogen and nitrite nitrogen were almost completely removed between 0-3mg / L, with NRE≥95%. At this stage, in order to ensure the adaptation of the side stream anaerobic ammonia oxidation activated sludge to the environment, the hydraulic retention time was not adjusted, so the NRR was between 127±3mg N L-1d-1. In the following 40-60 days, the hydraulic retention time was adjusted from 14h to 9.33h. The concentrations of effluent ammonia nitrogen and nitrite nitrogen fluctuated within 7 days after the adjustment. The highest effluent concentration of ammonia nitrogen was 23.63mg / L on the 42nd day, and then returned to normal. It shows that shortening the hydraulic retention time has a certain degree of impact on the microbial community in the system. The return to normal after the fluctuation shows that it has a certain degree of resistance to environmental changes, and this adjustment of the hydraulic retention time also enhances its resistance to environmental disturbances to a certain extent. At this time, the NRR in the system finally stabilized at 204±6mg N L-1d-1, the concentrations of effluent ammonia nitrogen and nitrite nitrogen were close to 0, and NRE≥95%. After the effluent ammonia nitrogen concentration was 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, 60-85 days, and the highest effluent ammonia nitrogen concentration reached 40.15 mg / L, and then slowly decreased until it finally stabilized at 2±2 mg / L. The longer fluctuation period of effluent ammonia nitrogen this time shows that the adjustment of hydraulic retention time has a greater impact on the stability of the system, and it requires a longer time to adapt and recover. However, the effluent ammonia nitrogen concentration was finally able to stabilize below 5 mg / L, indicating that this adjustment is still within the tolerance range of the system. After the adjustment, the NRR of the system 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 obtain 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) was 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 can 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, before 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 a method for rapidly restoring the denitrification efficiency of an anaerobic ammonium oxidation system

[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 the 20th day of the experiment, the effluent ammonia nitrogen concentration dropped rapidly to 3±3 mg / L after the reactor was inoculated with side-flow anammox activated sludge. However, since the 29th day, the effluent ammonia nitrogen concentration has rebounded. After two adjustment cycles, the final effluent ammonia nitrogen concentration was 53±2 mg / L, NRE was 36±2%, and NRR was 100+10 mg N L-1d-1. This shows that only the side-flow anammox activated sludge was inoculated into the reactor. Due to the poor resistance of the side-flow anammox activated sludge to environmental changes, it only showed its high activity in the first 9 days of inoculation. However, with the impact of the environment, the activity of the side-flow anammox activated sludge gradually decreased. In the end, compared with the above experiment, the effluent ammonia nitrogen concentration was about 50 mg / L higher, while the NRR was only about 1 / 3 of the above experiment. Therefore, it shows that 6 mg / L FeCl3 has a significant effect on improving the environmental resistance of side-flow anammox activated sludge.

[0074] Although the present invention is 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 ≥14h; S2. When the ammonia nitrogen effluent concentration of the reactor is stabilized below 5 mg / L and maintained for T1 day, shorten the hydraulic retention time to 9-10 h; S3. After shortening the hydraulic retention time in step S2, the ammonia nitrogen concentration in the reactor effluent will fluctuate. After the ammonia nitrogen effluent concentration continues to stabilize below 5 mg / L and remains for T2 days, the hydraulic retention time is further shortened to 7 h. ， After that, the ammonia nitrogen concentration in the reactor effluent will fluctuate. After the anaerobic ammonia-oxidizing bacteria adapt to the environment, the subsequent ammonia nitrogen effluent concentration will remain stable below 5 mg / L and maintained 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 small balls into the reactor so that a layer of hollow small 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 ball is made of plastic, and the diameter of the hollow ball is 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 influent is added with Fe 3+ The content is 5-6mg / L.

5. 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.

6. 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.

7. 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.

8. The method for rapidly recovering the denitrification efficiency of an anaerobic ammonium oxidation system according to any one of claims 1 to 7, 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.

9. The method for rapidly recovering the denitrification efficiency of an anaerobic ammonium oxidation system according to any one of claims 1 to 7, 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 hours, 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.

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

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