Device and method for enriching anaerobic ammonium oxidation bacteria and intensifying denitrification in AOA (anaerobic ammonium oxidation) process

Abstract

The invention relates to the field of biological denitrification sewage treatment, and particularly discloses a device and a method for anaerobic ammonium oxidation bacteria enrichment and enhanced denitrification in an AOA process. A device for anaerobic ammonium oxidation bacteria enrichment and enhanced denitrification in an AOA process comprises a raw water tank, an AOA bioreactor, a secondary sedimentation tank and a PLC, the AOA bioreactor comprises an anaerobic zone, a high-load aerobic zone, a low-load aerobic zone, an anoxic zone and a reoxygenation zone, a first filler screen box is arranged in the high-load aerobic zone, and a second filler screen box is arranged in the anoxic zone; the method comprises the following steps that sewage sequentially flows through a high-load aerobic zone, a low-load aerobic zone, an anoxic zone and a reoxygenation zone from an anaerobic zone and is precipitated in a secondary sedimentation tank, and supernate is effluent. The device and the method are matched for use, the abundance and the activity of anaerobic ammonium oxidation bacteria in an anoxic zone of the system can be improved through a biological membrane alternate circulation strategy, and the autotrophic nitrogen removal efficiency of the system is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of biological denitrification wastewater treatment, and in particular to a device and method for enriching and strengthening denitrification of anaerobic ammonia oxidation bacteria in an AOA process. BACKGROUND

[0002] Deep denitrification of wastewater is the focus in recent years. At present, many wastewater treatment plants still face the situation or risk that total nitrogen cannot meet the standard discharge. In order to meet the increasingly stringent emission requirements, the method of adding external carbon source is widely used to strengthen denitrification, but the cost of adding carbon source is quite high and additional post-protection units are needed to remove residual organic matter. On the other hand, a large amount of aeration is needed to complete nitrification, which occupies a high proportion of the operation energy consumption of the entire wastewater treatment plant. Therefore, seeking new denitrification technologies and processes with low consumption, high efficiency and stability has become an urgent goal of the water treatment industry.

[0003] As a newly developed biological denitrification process in recent years, the AOA process has the typical feature of post-positioning of the anoxic zone and the denitrification path of endogenous denitrification compared with the traditional AAO process. The denitrification efficiency of the AAO process is limited by the total reflux ratio of the system, and the denitrification efficiency is generally lower than 80%. The AOA process overcomes the limitation of the denitrification efficiency depending on the reflux ratio in the AAO process, and can achieve nearly 100% removal of nitrogen pollutants in wastewater under ideal conditions, which has the potential to achieve deep denitrification.

[0004] Anaerobic ammonia oxidation reaction is a reaction in which anaerobic ammonia oxidation bacteria reduce nitrite nitrogen to nitrogen gas under anoxic or limited oxygen conditions. As an efficient biological denitrification technology, anaerobic ammonia oxidation has good development and application prospects due to its high volumetric removal efficiency. The research on the anaerobic ammonia oxidation process began at the end of the 20th century and was successfully developed at the beginning of the 21st century. At present, there are many successful cases in the denitrification treatment of high-concentration ammonia-nitrogen wastewater such as landfill leachate, sludge digestion liquid, kitchen waste liquid and yeast wastewater. However, the bottleneck problem of directly treating actual municipal wastewater by the anaerobic ammonia oxidation process still needs to be broken through, including slow growth of anaerobic ammonia oxidation bacteria, unstable retention, and inhibition effect at low temperature.

[0005] In the AOA process, coupling anaerobic ammonia oxidation technology can achieve deep denitrification of wastewater while reducing the generation of greenhouse gases in the wastewater treatment process, achieving the purpose of energy saving and consumption reduction of wastewater treatment. The AOA process coupled with anaerobic ammonia oxidation technology provides a feasible idea for the wastewater treatment industry to achieve the carbon neutralization goal and build a green low-carbon benchmark plant for wastewater treatment. SUMMARY

[0006] In order to solve the above technical problems, the present application provides a device and method for enriching and strengthening denitrification of anaerobic ammonia oxidation bacteria in an AOA process.

[0007] In a first aspect, the application provides a device for enriching and strengthening denitrification of anaerobic ammonia oxidation bacteria in an AOA process, comprising a raw water tank, an AOA bioreactor, a secondary sedimentation tank and a PLC controller connected in sequence, wherein the AOA bioreactor comprises an anaerobic zone, a high-load aerobic zone, a low-load aerobic zone, an anoxic zone and a reoxygenation zone connected in sequence, the reoxygenation zone is connected with the secondary sedimentation tank through an overflow pipe, and the secondary sedimentation tank is connected with the anaerobic zone through a reflux pump; The high-load aerobic zone is provided with an aeration disc and a first filler screen box above the aeration disc, the low-load aerobic zone and the reoxygenation zone are each provided with an aeration disc, and the anoxic zone is provided with a second filler screen box (2.17). The aeration disc in the high-load aerobic zone is connected with a first gas regulating valve, the aeration disc in the low-load aerobic zone is connected with a second gas regulating valve, the aeration disc in the reoxygenation zone is connected with a third gas regulating valve, and the first, second and third gas regulating valves are controlled by the PLC controller.

[0008] The first filler screen box, the second filler screen box, the high-load aerobic zone and the anoxic zone are each provided with suspended fillers.

[0009] Preferably, the suspended fillers in the first filler screen box account for 5-10% of the effective volume of the high-load aerobic zone, and the suspended fillers in the second filler screen box account for 5-10% of the effective volume of the anoxic zone.

[0010] Preferably, the suspended fillers in the high-load aerobic zone account for 5-10% of the effective volume of the high-load aerobic zone, and the suspended fillers in the anoxic zone account for 5-10% of the effective volume of the anoxic zone.

[0011] Preferably, the specific surface density of the suspended fillers is 450-500 m 2 / m 3 .

[0012] Preferably, the high-load aerobic zone is provided at the end with a first dissolved oxygen detection probe, the low-load aerobic zone is provided at the end with a second dissolved oxygen detection probe and a first ammonia nitrogen detection probe, the anoxic zone is provided at the end with a second ammonia nitrogen detection probe, and the reoxygenation zone is provided at the end with a third dissolved oxygen detection probe.

[0013] Preferably, the first, second, first, second and third dissolved oxygen detection probes are controlled by the PLC controller.

[0014] In a second aspect, the application also provides a method for enriching and strengthening denitrification of anaerobic ammonia oxidation bacteria in an AOA process, comprising the following steps: S1. The sewage is introduced into the raw water tank, and the backflow sludge from the secondary sedimentation tank is introduced into the anaerobic zone for denitrification reaction, and the hydraulic retention time of the anaerobic zone is 1.5-4h; S2. The mixed wastewater flows from the anaerobic zone to the high-load aerobic zone for short-cut nitrification coupled with anaerobic ammonia oxidation reaction, and the dissolved oxygen concentration in the high-load aerobic zone is controlled to be 0.3-0.7mg / L, and the hydraulic retention time is 1-2h, and after running for 30-60d, the situation in the high-load aerobic zone is monitored, and when the total nitrogen loss is >2mg / L, the red-brown substance appears in the suspended filler in the high-load aerobic zone, and the relative abundance of the order of Candidatus Brocadia is >0.1%, it is determined that the anaerobic ammonia oxidation bacteria are self-enriched in the high-load aerobic zone without adding seed sludge; S3. The mixed wastewater flows from the high-load aerobic zone to the low-load aerobic zone for nitrification reaction, and the end ammonia nitrogen concentration in the low-load aerobic zone is controlled to be 1.5-2.5mg / L, and the hydraulic retention time is 2-4h; S4. The mixed wastewater flows from the low-load aerobic zone to the anoxic zone for short-cut denitrification coupled with anaerobic ammonia oxidation reaction, and the hydraulic retention time is 3.5-7h, and after running for 30-60d, the situation in the low-load aerobic zone and the anoxic zone is monitored, and when the ammonia nitrogen concentration difference between the low-load aerobic zone and the anoxic zone is greater than 0.3mg / L, the red-brown substance appears in the suspended filler in the anoxic zone, and the relative abundance of the order of Candidatus Brocadia is >0.1%, it is determined that the anaerobic ammonia oxidation bacteria are self-enriched in the anoxic zone without adding seed sludge; S5. The mixed wastewater flows from the anoxic zone to the reoxygenation zone for nitrification reaction, and the dissolved oxygen concentration in the reoxygenation zone is controlled to be ≥1.5mg / L, and the hydraulic retention time is 0.5-1h; S6. The mixed wastewater flows from the reoxygenation zone to the secondary sedimentation tank for sedimentation, and the obtained sludge is backflowed to the anaerobic zone, and the sludge backflow ratio is 50-150%, and the obtained supernatant is effluent, and is discharged by a device; the sludge backflow ratio is controlled to be 50-150%.

[0015] Preferably, when the anaerobic ammonia oxidation bacteria are self-enriched in the high-load aerobic zone and the anoxic zone without adding seed sludge, a biological membrane carrier exchange circulation mode is set, the circulation period is 90-180d, the carrier filler in the first filler screen box is exchanged with the carrier filler in the second filler screen box, and after running for 30-60d, the carrier filler in the first filler screen box is exchanged with the carrier filler in the second filler screen box again, and after running for 60-120d, the circulation is completed; if the TN value of the effluent in S6 is increased after the circulation is completed, the biological membrane carrier exchange circulation mode is repeated.

[0016] Preferably, the floc sludge concentration in the AOA biological reactor is controlled to be 4000-7000mg / L, and the floc sludge age is controlled to be 7-15d.

[0017] By adopting the above technical solution, this application provides attachment and growth sites for anaerobic ammonia oxidizing bacteria by adding loading materials to the high-load aerobic zone and anoxic zone, controls the low-DO enhanced short-cut nitrification coupled with anaerobic ammonia oxidation reaction in the high-load aerobic zone, and realizes the in-situ enrichment of anaerobic ammonia oxidizing bacteria in the aerobic zone. In the anoxic environment, endogenous denitrifying bacteria in the flocculent sludge use their own stored internal carbon sources to carry out short-cut denitrification, reducing nitrate nitrogen to nitrite nitrogen. The coexistence of ammonia nitrogen and nitrite nitrogen provides reaction conditions for the in-situ enrichment of anaerobic ammonia oxidizing bacteria in the anoxic zone. Through the biofilm alternating circulation strategy, the abundance and activity of anaerobic ammonia oxidizing bacteria in the anoxic zone of the system are improved, and the autotrophic denitrification efficiency of the system is improved. Compared to existing technologies, this application uses partitioning to control and enhance short-range nitrification coupling, and utilizes carrier exchange to improve denitrification stability. In the absence of a biofilm carrier exchange cycle, results show that after 45 days of biofilm formation on the blank packing material, in-situ enrichment of anaerobic ammonia-oxidizing bacteria can be achieved on both the high-load aerobic and anoxic biofilms. The anaerobic ammonia-oxidizing functional bacteria genus (…) Ca. Brocadia The relative abundances of NH4+ and NH4+ were 0.18% and 0.25%, respectively. Meanwhile, water quality data along the route showed that the TN removal value in the high-load aerobic zone was 3.5 mg / L, while NH4+ was observed in the anoxic zone. + -N decreased by approximately 0.4 mg / L. The experiment also showed that after continuing to operate the device for 30 days according to the methods described in steps S1-S6, monitoring of the biofilm in the hypoxic zone... Ca. Brocadia The relative abundance was 0.54%, and the functional activity of anaerobic ammonia oxidizing bacteria was 13.2 g NH4. + -N / m 3 ·d, the contribution rate of anaerobic ammonia oxidation in the anoxic zone is 8.7%. At this time, biofilm alternation and circulation are implemented according to S7, that is, the biofilm in the anoxic zone is swapped with the biofilm in the high-load aerobic zone. After 50 days of operation, the anoxic biofilm is then reset from the high-load aerobic zone to the anoxic zone. At this time, the concentration of anaerobic biofilm in the reset anoxic zone is monitored. Ca. Brocadia The relative abundance was 1.40%, and the functional activity of anaerobic ammonia oxidizing bacteria was 38.1 gNH4. + -N / m 3 •d. The contribution rate of anaerobic ammonia oxidation in the anoxic zone increased from 8.7% before S7 to 20.5%. After 70 days of continued operation, the average value of the system effluent can be further reduced, and the TN removal rate can be increased by 10%, achieving the ultimate denitrification operation state. Therefore, the biofilm carrier exchange and circulation mode of this application can significantly improve the abundance of anaerobic ammonia oxidation bacteria in the anoxic zone biofilm, the system autotrophic denitrification contribution rate, and the effluent quality.

[0018] Specifically, sewage is fed from the raw water tank into the first end of the anaerobic zone of the AOA biological reactor by the water inlet pump, and at the same time, the return sludge from the bottom of the secondary sedimentation tank is also fed back by the sludge return pump, the sludge return ratio is 50-150%, and the hydraulic retention time is 1.5-4h, at this time, the denitrifying bacteria reduce the nitrate in the return sludge to nitrogen gas by using the organic matter in the influent, and the endogenous denitrifying bacteria convert the volatile fatty acids (VFAs) in the influent into intracellular PHAs and other substances.

[0019] Subsequently, the mixed wastewater enters the high-load aerobic zone, and the hydraulic retention time is 1-2h, and then the dissolved oxygen parameter feedback control program is set by the PLC control box, when the first dissolved oxygen detection probe measures the dissolved oxygen (DO) value >0.7mg / L, the first gas regulating valve opening is adjusted smaller, when the first dissolved oxygen detection probe measures the DO value <0.3mg / L, the first gas regulating valve opening is adjusted larger, so as to control the DO range in the high-load aerobic zone to be 0.3-0.7mg / L, and the low-DO environment and high-organic load environment in the high-load aerobic zone are fully utilized to realize partial inhibition of nitrite oxidizing bacteria activity, form partial short-cut nitrification coupled with anaerobic ammonia oxidation reaction, and the suspended filler provides an attachment growth carrier for the enrichment of anaerobic ammonia oxidation bacteria.

[0020] The mixed wastewater enters the low-load aerobic zone from the end of the high-load aerobic zone, and the ammonia nitrogen parameter feedback control program is set by the PLC control box, when the first ammonia nitrogen detection probe measures the ammonia nitrogen value >2.5mg / L, the second gas regulating valve opening is adjusted larger, when the first ammonia nitrogen detection probe measures the ammonia nitrogen value <1.5mg / L, the second gas regulating valve opening is adjusted smaller, the ammonia nitrogen concentration range at the end of the low-load aerobic zone is controlled to be 1.5-2.5mg / L, and the hydraulic retention time of the low-load aerobic zone is controlled to be 2-4h, so as to promote the nitrifying bacteria to carry out nitrification reaction.

[0021] The mixed wastewater enters the anoxic zone from the end of the low-load aerobic zone, and the average hydraulic retention time in the anoxic zone is controlled to be 3.5-7h, the endogenous short-cut denitrifying bacteria in the anoxic zone utilize the internal carbon source stored in the anaerobic section to reduce the nitrate nitrogen generated in the low-load aerobic zone to nitrite nitrogen.

[0022] Subsequently, the mixed wastewater enters the reoxygenation zone from the anoxic zone, the average hydraulic retention time in the reoxygenation zone is controlled to be 0.5-1h, and the dissolved oxygen is not less than 1.5mg / L, the nitration reaction occurs to oxidize the residual ammonia nitrogen in the mixed liquid, and the nitrogen gas generated in the anoxic zone is stripped to improve the sludge settling performance.

[0023] The mixed wastewater from the overflow pipe connected from the reoxygenation zone enters the secondary sedimentation tank to realize mud-water separation, the supernatant in the secondary sedimentation tank is discharged from the device through the drain pipe as effluent, and the sludge at the bottom of the secondary sedimentation tank is returned through the return pump and enters the first end of the anaerobic zone of the AOA biological reactor together with the new incoming wastewater to continue the new anaerobic ammonia oxidation bacteria enrichment and intensified denitrification and water purification process.

[0024] On the basis of the above, the application also strictly monitors whether the anaerobic ammonia oxidation bacteria can be self-enriched without adding seed sludge in the high-load aerobic zone and the anoxic zone, and immediately after the realization, a biofilm carrier exchange circulation mode is set to improve the activity of anaerobic ammonia oxidation and the contribution rate of autotrophic denitrification in the anoxic zone of the system, which represents that the abundance of anaerobic ammonia oxidation bacteria is improved, and the denitrification capacity of the system is further stabilized and optimized.

[0025] In summary, the application has the following beneficial technical effects: 1. The method of the application provides an attachment growth site for anaerobic ammonia oxidation bacteria enrichment to the carrier in the high-load aerobic zone and the anoxic zone, controls the short-cut nitrification coupled with anaerobic ammonia oxidation reaction in the high-load aerobic zone with low DO to realize in-situ enrichment of anaerobic ammonia oxidation bacteria in the aerobic zone, and the endogenous denitrifying bacteria in the flocculent sludge utilize the internal carbon source stored by themselves to carry out short-cut denitrification to reduce nitrate nitrogen to nitrite nitrogen, and ammonia nitrogen and nitrite nitrogen coexist to provide reaction conditions for in-situ enrichment of anaerobic ammonia oxidation bacteria in the anoxic zone; 2. The biofilm carrier exchange circulation mode of the application can obviously improve the abundance of anaerobic ammonia oxidation bacteria group in the anoxic zone, the contribution rate of autotrophic denitrification of the system and the effluent water quality. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 It is a schematic diagram of a device for anaerobic ammonia oxidation bacteria enrichment and intensified denitrification in an AOA process of the application.

[0027] BRIEF DESCRIPTION OF DRAWINGS 1. raw water tank; 1.1, water inlet pump; 2, AOA biological reactor; 2.1, anaerobic zone; 2.2, high-load aerobic zone; 2.3, low-load aerobic zone; 2.4, anoxic zone; 2.5, reoxygenation zone; 2.6, overflow pipe; 2.7, agitator; 2.8, aeration fan; 2.9, first gas regulating valve; 2.10, aeration disc; 2.11, second gas regulating valve; 2.13, first dissolved oxygen detection probe; 2.14, first filler screen box; 2.15, second dissolved oxygen detection probe; 2.16, first ammonia nitrogen detection probe; 2.17, second filler screen box; 2.18, second ammonia nitrogen detection probe; 2.19, third dissolved oxygen detection probe; 2.20, suspended filler; 3, secondary sedimentation tank; 3.1, sludge return pump; 3.2, drain pipe; 3.3, sludge discharge pipe; 4, PLC control box. DETAILED DESCRIPTION

[0028] Material source The raw materials used in the application are commercially available products, specifically: The suspended filler is PE filler with a specific surface density of 450-500 m 2 / m 3 .

[0029] Sewage, ordinary municipal sewage, COD is 120-260 mg / L, NH4 + -N is 25-45 mg / L, TN is 30-50 mg / L, and TP is 2-6 mg / L.

[0030] The application will be further described in detail below in combination with examples and comparative examples. Examples

[0031] The device for enriching and strengthening denitrification of anaerobic ammonia oxidation bacteria in AOA process comprises a raw water tank 1, an AOA biological reactor 2, a secondary sedimentation tank 3 and a PLC controller 4 connected in sequence; the AOA biological reactor 2 comprises an anaerobic zone 2.1, a high-load aerobic zone 2.2, a low-load aerobic zone 2.3, an anoxic zone 2.4 and a reoxygenation zone 2.5 in sequence; the raw water tank 1 is connected with the first section of the anaerobic zone 2.1 through a water inlet pump 1.1, the anaerobic zone 2.1 is connected with the high-load aerobic zone 2.2, the high-load aerobic zone 2.2 is connected with the low-load aerobic zone 2.3, the low-load aerobic zone 2.3 is connected with the anoxic zone 2.4, the anoxic zone 2.4 is connected with the reoxygenation zone 2.5, and the reoxygenation zone 2.5 is connected with the secondary sedimentation tank 3 through an overflow pipe 2.6; the bottom of the secondary sedimentation tank 3 is connected with the first section of the anaerobic zone 2.1 through a sludge return pump 3.1, the effluent of the secondary sedimentation tank 3 is discharged through a drain pipe 3.2, and sludge is discharged from a sludge discharge pipe 3.3 at regular intervals; the anaerobic zone 2.1 and the anoxic zone 2.4 in the AOA biological reactor 2 are both provided with a stirrer 2.7; an aeration blower 2.8 is connected with an aeration disc 2.10 in the high-load aerobic zone 2.2 through a first gas regulating valve 2.9, connected with an aeration disc 2.10 in the low-load aerobic zone 2.3 through a second gas regulating valve 2.11 and connected with an aeration disc 2.10 in the reoxygenation zone 2.5 through a third gas regulating valve 2.12; the end of the high-load aerobic zone 2.2 is provided with a first dissolved oxygen detection probe 2.13 and a first filler screen box 2.14; the end of the low-load aerobic zone 2.3 is provided with a second dissolved oxygen detection probe 2.15 and a first ammonia nitrogen detection probe 2.16; the anoxic zone 2.4 is provided with a second filler screen box 2.17 and a second ammonia nitrogen detection probe 2.18; the end of the reoxygenation zone 2.5 is provided with a third dissolved oxygen detection probe 2.19; the PLC controller 4 is connected with the aeration blower 2.8, the first gas regulating valve 2.9, the second gas regulating valve 2.11, the third gas regulating valve 2.12, the first dissolved oxygen detection probe 2.13, the second dissolved oxygen detection probe 2.15, the third dissolved oxygen detection probe 2.19, the first ammonia nitrogen detection probe 2.16 and the second ammonia nitrogen detection probe 2.18. The first filler screen box 2.14 is placed with suspended filler 2.20, the specific surface density of the suspended filler is 450-500 m 2 / m 3 , the filling ratio of the filler accounts for 5%-10% of the effective volume of the high-load aerobic zone, the second filler screen box 2.17 is also placed with suspended filler 2.20, and the amount of filler added is consistent with that of the first screen box 2.14; suspended filler 2.20 is also added outside the filler screen box in the high-load aerobic zone 2.2 and the anoxic zone 2.4, the specific surface density of the suspended filler is 450-500 m 2 / m 3 , and the filling ratio of the filler is 10%-20%.

[0032] The above device is used for treating municipal sewage, and a method for enriching and strengthening denitrification of anaerobic ammonia oxidation bacteria in AOA process comprises the following steps: S1. The municipal sewage is poured into the raw water tank 1, and then the municipal sewage is pumped into the front end of the anaerobic zone 2.1 of the AOA bioreactor 2 by the water pump 1.1, and at the same time, the return sludge from the bottom of the secondary sedimentation tank 3 pumped back by the sludge return pump 3.1 is also introduced, the sludge return ratio is 50-150%, after mixing, the two undergo denitrification reaction in the anaerobic zone 2.1, the control of the hydraulic retention time is 1.5-4h, the denitrifying bacteria will reduce the nitrate in the return sludge to nitrogen gas by using the organic matter in the influent, and the endogenous denitrifying bacteria will convert the volatile fatty acids VFAs in the influent into substances such as PHAs, after the denitrification is completed, the mixed wastewater flows out from the end of the anaerobic zone 2.1, the activated sludge concentration in the AOA bioreactor 2 is controlled to be 4000-7000mg / L during the reaction, and the floc sludge age is controlled to be 7-15d; S2. The mixed wastewater flowing out from the end of the anaerobic zone 2.1 enters the high-load aerobic zone 2.2, the dissolved oxygen parameter feedback control program is set by the PLC control box 4, when the first dissolved oxygen detection probe 2.13 measures the value >0.7mg / L, the first gas regulating valve 2.9 opening is adjusted smaller, when the first dissolved oxygen detection probe 2.13 measures the value <0.3mg / L, the first gas regulating valve 2.9 opening is adjusted larger, the overall control of the dissolved oxygen concentration in the high-load aerobic zone 2.2 is 0.3-0.7mg / L, and the hydraulic retention time is controlled to be 1-2h, after running for 30-60d, if the total nitrogen loss is >2mg / L, the reddish-brown biological community can be observed on the suspended filler 2.10, and the microbial detection means shows that the relative abundance of the Aeromicrobia anaerobic ammonia oxidation bacteria genus is >0.1%, it is determined that the high-load aerobic zone 2.2 realizes self-enrichment of anaerobic ammonia oxidation bacteria without adding seed sludge, and the mixed wastewater after partial shortcut nitrification coupled with anaerobic ammonia oxidation reaction flows out from the end of the high-load aerobic zone 2.2; S3. The mixed wastewater flowing out from the end of the high-load aerobic zone 2.2 enters the low-load aerobic zone 2.3, the ammonia nitrogen parameter feedback control program is set by the PLC control box 4, when the first ammonia nitrogen detection probe 2.16 measures the ammonia nitrogen value >2.5mg / L, the second gas regulating valve 2.11 opening is adjusted larger, when the first ammonia nitrogen detection probe 2.16 measures the ammonia nitrogen value <1.5mg / L, the second gas regulating valve 2.11 opening is adjusted smaller, the overall control of the ammonia nitrogen concentration at the end of the low-load aerobic zone 2.3 is 1.5-2.5mg / L, and the hydraulic retention time of the low-load aerobic zone 2.3 is controlled to be 2-4h, under this environment, the nitrifying bacteria carry out nitrification reaction, and the mixed wastewater after nitrification flows out from the end of the low-load aerobic zone 2.3; S4. The mixed wastewater flowing out from the end of the low-load aerobic zone 2.3 enters the anoxic zone 2.4, and the average hydraulic retention time is controlled to be 3.5-7 h. The endogenous short-cut denitrifying bacteria in the anoxic zone 2.4 play a role, and utilize the internal carbon source stored in the anaerobic section to reduce the nitrate nitrogen generated in the low-load aerobic zone 2.3 into nitrite nitrogen. The mixed wastewater is subjected to denitrification coupled with anaerobic ammonia oxidation reaction. After 30-60 days of operation, if the difference between the long-term monitoring value sliding average of the first ammonia nitrogen detection probe 2.16 and the long-term monitoring value sliding average of the second ammonia nitrogen detection probe 2.18 is greater than 0.3 mg / L, the reddish-brown biological community can be observed on the suspended filler 2.10, and the relative abundance of the Planctomycetes anaerobic ammonia oxidation bacteria genus is greater than 0.1% as shown by the microbial detection means, it is determined that the anoxic zone 2.4 realizes self-enrichment of anaerobic ammonia oxidation bacteria without adding seed sludge, and the mixed wastewater subjected to denitrification coupled with anaerobic ammonia oxidation reaction flows out from the end of the anoxic zone 2.4; S5. The mixed wastewater flowing out from the end of the anoxic zone 2.4 flows into the reoxygenation zone 2.5, and the average hydraulic retention time of the reoxygenation zone 2.5 is controlled to be 0.5-1 h, and the dissolved oxygen is greater than or equal to 1.5 mg / L. The nitrification reaction is performed to oxidize the residual ammonia nitrogen in the mixed wastewater, and the nitrogen gas generated in the anoxic zone 2.4 is stripped to improve the sludge settling performance. The mixed wastewater subjected to nitrification flows out from the end of the reoxygenation zone 2.5; S6. The mixed wastewater flowing out from the end of the reoxygenation zone 2.5 passes through the overflow pipe 2.6 and enters the secondary sedimentation tank 3, and the sludge and water are separated. After a period of standing, the supernatant in the secondary sedimentation tank 3 is discharged from the water outlet pipe 3.3, and the effluent is obtained. The sludge at the bottom of the secondary sedimentation tank 3 is pumped back to the first section of the anaerobic zone 2.1 by the sludge return pump 3.1, and is subjected to denitrification reaction together with the municipal wastewater. S7. After it is determined in S2 and S4 that the anaerobic ammonia oxidation bacteria are self-enriched without adding seed sludge, the biological membrane carrier exchange cycle mode is set to improve the anaerobic ammonia oxidation activity and autotrophic denitrification contribution rate of the system in the anoxic zone. The cycle period is 90-180 days. The suspended filler 2.20 in the first filler screen box 2.14 is alternately exchanged with the suspended filler 2.20 in the second filler screen box 2.17. After 30-60 days of operation, the suspended filler 2.20 in the first filler screen box 2.14 is alternately exchanged with the suspended filler 2.20 in the second filler screen box 2.17. Finally, after 60-120 days of operation, the cycle process is completed.

[0033] Performance detection

[0034] In combination with the above embodiment, the efficiency of the device and method is investigated by taking the conventional municipal wastewater as the treatment object.

[0035] Table 1 shows the water quality of the effluent of S6 without implementing S7 and the water quality of the effluent of S6 after implementing S7; Table 2 shows the in-situ enrichment of anaerobic ammonia-oxidizing bacteria in the biofilm (suspended packing) of the high-load aerobic zone and the anoxic zone. Table 3 shows the operation of the biofilm (suspended packing) in the anoxic zone before S7 was implemented and the operation of the biofilm (suspended packing) in the anoxic zone after S7 was implemented.

[0036]

[0037]

[0038]

[0039] Data Analysis: As can be seen from Table 1, the method implemented using the device of this application can effectively purify municipal sewage, and the effluent quality is better than the national Class A discharge standard for sewage. It can be seen that the method of this application provides attachment and growth sites for anaerobic ammonia oxidizing bacteria by adding loading materials to the high-load aerobic zone and the anoxic zone, controls the low DO enhanced short-cut nitrification coupled with anaerobic ammonia oxidation reaction in the high-load aerobic zone, and realizes the in-situ enrichment of anaerobic ammonia oxidizing bacteria in the aerobic zone. In the anoxic environment, the endogenous denitrifying bacteria in the flocculent sludge use their own stored internal carbon source to carry out short-cut denitrification, reducing nitrate nitrogen to nitrite nitrogen. The coexistence of ammonia nitrogen and nitrite nitrogen provides reaction conditions for the in-situ enrichment of anaerobic ammonia oxidizing bacteria in the anoxic zone.

[0040] After implementing the operation in S7, TN can be further reduced to 1.0-4.0 mg / L, which shows that the biofilm carrier exchange circulation mode of this application can significantly improve the effluent quality.

[0041] Table 2 shows that, 45 days after biofilm formation, the anaerobic ammonia-oxidizing bacteria genus ( ) were present in both the high-load aerobic zone and the anoxic zone biofilm. Ca. Brocadia The relative abundances of anaerobic ammonia-oxidizing bacteria were 0.18% and 0.25%, respectively, indicating that in-situ enrichment of anaerobic ammonia-oxidizing bacteria had been achieved. Meanwhile, water quality data along the pipeline showed that the total nitrogen (TN) removal rate in the high-load aerobic zone was 3.5 mg / L, while NH4+ was observed in the anoxic zone. + -N decreased by approximately 0.4 mg / L.

[0042] As can be seen from Table 3, after continuing operation for 30 days using methods S1-S6, the biofilm in the hypoxic zone... Ca. Brocadia The relative abundance was 0.54%, and the functional activity of anaerobic ammonia oxidizing bacteria was 13.2 g NH4. + -N / m 3·d, the contribution rate of anaerobic ammonia oxidation in the anoxic zone is 8.7%. At this time, the biofilm carrier exchange cycle mode is implemented according to S7, that is, the biofilm in the anoxic zone is swapped with the biofilm in the high-load aerobic zone. After running for 50 days, the anoxic biofilm is then reset from the high-load aerobic zone to the anoxic zone. At this time, the concentration of anaerobic biofilm in the reset anoxic zone is monitored. Ca. Brocadia The relative abundance was 1.40%, and the functional activity of anaerobic ammonia oxidizing bacteria was 38.1 gNH4. + -N / m 3 •d. The contribution rate of anaerobic ammonia oxidation in the anoxic zone increased from 8.7% before S7 to 20.5%. After 70 days of continued operation, the average value of the system effluent can be further reduced, and the TN removal rate can be increased by 10%, achieving the operating state of ultimate denitrification. After the implementation of S7, the abundance of anaerobic ammonia oxidation bacteria in the biofilm of the anoxic zone, the contribution rate of autotrophic denitrification in the system, and the effluent quality have all been significantly improved. It can be seen that the biofilm carrier exchange and circulation mode of this application can improve the abundance of anaerobic ammonia oxidation bacteria in the biofilm of the anoxic zone and the contribution rate of autotrophic denitrification in the system.

[0043] The embodiments described in this specific implementation are preferred embodiments of this application and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A device for enriching and enhancing denitrification with anaerobic ammonia-oxidizing bacteria in an AOA process, characterized in that, The system includes a raw water tank (1), an AOA bioreactor (2), a secondary sedimentation tank (3), and a PLC controller (4) connected in sequence. The AOA bioreactor (2) includes an anaerobic zone (2.1), a high-load aerobic zone (2.2), a low-load aerobic zone (2.3), an anoxic zone (2.4), and a reoxygenation zone (2.5) connected in sequence. The reoxygenation zone (2.5) is connected to the secondary sedimentation tank (3) through an overflow pipe (2.6), and the secondary sedimentation tank (3) is connected to the anaerobic zone (2.1) through a return pump (3.1). The high-load aerobic zone (2.2) is equipped with an aeration disc (2.10) and a first packing screen box (2.14) located above the aeration disc (2.10). The low-load aerobic zone (2.3) and the reoxygenation zone (2.5) are both equipped with an aeration disc (2.10). The anoxic zone (2.4) is equipped with a second packing screen box (2.17). The aeration disc (2.10) in the high-load aerobic zone (2.2) is connected to a first gas regulating valve (2.9), the aeration disc (2.10) in the low-load aerobic zone (2.3) is connected to a second gas regulating valve (2.11), and the aeration disc (2.10) in the reoxygenation zone (2.5) is connected to a third gas regulating valve (2.12). The first gas regulating valve (2.9), the second gas regulating valve (2.11), and the third gas regulating valve (2.12) are all controlled by a PLC controller (4).

2. Suspended packing material (2.20) is provided in the first packing screen box (2.14), the second packing screen box (2.17), the high-load aerobic zone (2.2) and the anoxic zone (2.4).

3. The apparatus for enriching and enhancing denitrification with anaerobic ammonia-oxidizing bacteria in an AOA process according to claim 1, characterized in that, The suspended filler (2.20) in the first filler screen box (2.14) accounts for 5-10% of the effective volume of the high-load aerobic zone (2.2); the suspended filler (2.20) in the second filler screen box (2.17) accounts for 5-10% of the effective volume of the anoxic zone (2.4).

4. The apparatus for enriching and enhancing denitrification of anaerobic ammonia-oxidizing bacteria in an AOA process according to claim 2, characterized in that, The suspended packing material (2.20) in the high-load aerobic zone (2.2) accounts for 5-10% of the effective volume of the high-load aerobic zone (2.2); the suspended packing material (2.20) in the anoxic zone (2.4) accounts for 5-10% of the effective volume of the anoxic zone (2.4).

5. The apparatus for enriching and enhancing denitrification with anaerobic ammonia-oxidizing bacteria in an AOA process according to claim 1, characterized in that, The specific surface area density of the suspended filler (2.20) is 450-500 m³. 2 / m 3 .

6. The apparatus for enriching and enhancing denitrification with anaerobic ammonia-oxidizing bacteria in an AOA process according to claim 1, characterized in that, The high-load aerobic zone (2.2) is equipped with a first dissolved oxygen probe (2.13) at its end, the low-load aerobic zone (2.3) is equipped with a second dissolved oxygen detection probe (2.15) and a first ammonia nitrogen detection probe (2.16) at its end, the anoxic zone (2.4) is equipped with a second ammonia nitrogen detection probe (2.18), and the reoxygenation zone (2.5) is equipped with a third dissolved oxygen detection probe (2.19) at its end.

7. The apparatus for enriching and enhancing denitrification with anaerobic ammonia-oxidizing bacteria in an AOA process according to claim 5, characterized in that, The first dissolved oxygen detection probe (2.13), the second dissolved oxygen detection probe (2.15), the first ammonia nitrogen detection probe (2.16), the second ammonia nitrogen detection probe (2.18), and the third dissolved oxygen detection probe (2.19) are all controlled by the PLC controller (4).

8. A method for enriching and enhancing denitrification with anaerobic ammonia-oxidizing bacteria in an AOA process, characterized in that, Includes the following steps: S1. The wastewater is fed into the raw water tank (1) and enters the anaerobic zone (2.1) together with the returned sludge from the secondary sedimentation tank (3) for denitrification. The hydraulic retention time of the anaerobic zone (2.1) is 1.5-4h. S2. The mixed wastewater flows from the anaerobic zone (2.1) into the high-load aerobic zone (2.2) for short-cut nitrification coupled with anaerobic ammonia oxidation reaction. The dissolved oxygen concentration in the high-load aerobic zone (2.2) is controlled at 0.3-0.7 mg / L, the hydraulic retention time is 1-2 h, and after running for 30-60 days, the condition of the high-load aerobic zone (2.2) is monitored. When the total nitrogen loss is >2 mg / L, reddish-brown substances appear in the suspended packing material (2.20) in the high-load aerobic zone (2.2), and the relative abundance of anaerobic ammonia oxidizing bacteria in the phylum Planicillium is >0.1%, it is considered that the high-load aerobic zone (2.2) has achieved self-enrichment of anaerobic ammonia oxidizing bacteria without the addition of seed sludge. S3. The mixed wastewater flows from the high-load aerobic zone (2.2) into the low-load aerobic zone (2.3) for nitrification. The final ammonia nitrogen concentration in the low-load aerobic zone (2.3) is controlled at 1.5-2.5 mg / L, and the hydraulic retention time is 2-4 h. S4. Mixed wastewater flows from the low-load aerobic zone (2.3) into the anoxic zone (2.4) for short-cut denitrification coupled with anaerobic ammonia oxidation reaction. The hydraulic retention time is 3.5-7h. After running for 30-60 days, the conditions in the low-load aerobic zone (2.3) and the anoxic zone (2.4) are monitored. When the difference in ammonia nitrogen concentration between the low-load aerobic zone (2.3) and the anoxic zone (2.4) is greater than 0.3mg / L, and reddish-brown substances appear in the suspended packing material (2.20) in the anoxic zone (2.4) and the relative abundance of anaerobic ammonia oxidizing bacteria in the phylum Planatum is >0.1%, it is considered that the anoxic zone (2.4) has achieved self-enrichment of anaerobic ammonia oxidizing bacteria without the addition of seed mud. S5. The mixed wastewater flows from the anoxic zone (2.4) into the reoxygenation zone (2.5) for nitrification. The dissolved oxygen concentration in the reoxygenation zone (2.5) is controlled to be ≥1.5mg / L, and the hydraulic retention time is 0.5-1h. S6. The mixed wastewater flows from the reoxygenation zone (2.5) into the secondary sedimentation tank (3) for sedimentation. The resulting sludge is returned to the anaerobic zone (2.1) with a sludge return ratio of 50-150%. The resulting supernatant is the effluent and is discharged from the device.

9. The method for enriching and enhancing denitrification with anaerobic ammonia-oxidizing bacteria in an AOA process according to claim 7, characterized in that, When anaerobic ammonia-oxidizing bacteria are self-enriched in the high-load aerobic zone (2.2) and anoxic zone (2.4) without the addition of seed sludge, a biofilm carrier exchange circulation mode is set up with a circulation cycle of 90-180 days. The carrier packing material (2.20) in the first packing screen box (2.14) is exchanged with the carrier packing material (2.20) in the second packing screen box (2.17). After running for another 30-60 days, the carrier packing material (2.20) in the first packing screen box (2.14) is exchanged with the carrier packing material (2.20) in the second packing screen box (2.17). After running for another 60-120 days, the circulation is completed. If the TN value of the effluent in S6 is found to increase after the circulation is completed, the biofilm carrier exchange circulation mode is repeated.

10. The method for enriching and enhancing denitrification with anaerobic ammonia-oxidizing bacteria in an AOA process according to claim 7, characterized in that, The concentration of flocculent sludge in the AOA bioreactor (2) is controlled at 4000-7000 mg / L, and the age of flocculent sludge is controlled at 7-15 days.

Images