Device and method for quickly starting short-cut nitrification anaerobic ammonia oxidation granular sludge system based on continuous flow CSTR (continuous stirred-tank reactor)
By inoculating aerobic granular sludge and short-cut nitrification anaerobic ammonium oxidation granular sludge into a continuous flow CSTR, and utilizing their inherent microenvironment and dynamic nitrogen loading strategy, the problems of slow start-up and poor stability of the PN/A process were solved, achieving rapid start-up and efficient and stable operation.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- BEIJING UNIV OF TECH
- Filing Date
- 2025-12-15
- Publication Date
- 2026-04-24
AI Technical Summary
The existing short-cut nitrification-anaerobic ammonium oxidation (PN/A) process has a long start-up time, difficulty in enriching AnAOB, and is sensitive to environmental changes, resulting in unstable operation and difficulty in efficiently removing nitrogen under dynamic wastewater quality conditions.
Aerobic granular sludge and short-cut nitrification anaerobic ammonium oxidation granular sludge were inoculated in a continuous flow CSTR to promote the colonization of anaerobic ammonium oxidation bacteria by utilizing their inherent anoxic/anaerobic microenvironment. A composite granular sludge structure was formed by dynamically increasing the nitrogen load in stages and washing flocculent sludge.
The system was able to start up quickly within 60 days, which improved the retention capacity of microorganisms, reduced energy consumption and excess sludge production, and enhanced the system's stability and resistance to shock loads.
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Figure CN121913626A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of wastewater biological treatment technology, specifically to a device and method for a rapid start-up short-cut nitrification anaerobic ammonium oxidation granular sludge system based on continuous flow CSTR. Background Technology
[0002] The integrated short-cut nitrification-anaerobic ammonium oxidation (PN / A) process is a novel biological nitrogen removal technology that utilizes the synergistic action of ammonia-oxidizing bacteria (AOB) and anaerobic ammonium-oxidizing bacteria (AnAOB) in a single reactor. The nitrite required for anaerobic ammonium oxidation can be provided by the short-cut nitrification reaction. In this process, AOB oxidizes ammonia nitrogen to nitrite nitrogen, which, along with residual ammonia nitrogen, is then converted to N2 by AnAOB. Compared to traditional nitrification / denitrification processes, the PN / A process saves 100% of organic carbon sources and 60% of aeration energy consumption, while also producing less residual sludge.
[0003] However, the PN / A process still has certain limitations in practical applications. AnAOB has a long doubling time, is difficult to enrich, and is very sensitive to environmental and water quality conditions. In reality, wastewater quality is dynamic, and frequent changes in environmental conditions reduce the activity of AnAOB, which is not conducive to its retention. This results in a long start-up time for the PN / A process, and it is also sensitive to changes in operating conditions, leading to unstable operation and thus limiting the denitrification efficiency.
[0004] Sludge granulation is considered a viable strategy for enriching slow-growing AnAOB and enhancing biomass retention. Short-cut nitrification anammox granular sludge has a longer sludge age in the reactor, which is conducive to the enrichment and accumulation of AnAOB, while its dense structure also improves the shock resistance of AnAOB. Therefore, how to rapidly cultivate and enrich short-cut nitrification anammox granular sludge to shorten start-up time and enhance system stability is key to promoting the application of this technology.
[0005] Compared to traditional wastewater treatment processes, aerobic granular sludge (AGS) technology offers advantages such as smaller footprint and energy efficiency, making it a promising biological wastewater treatment technology. AGS integrates various functional microorganisms within the granules and stratifies these microorganisms according to different redox conditions. Anoxic bacteria (AOB) and nitrite-oxidizing bacteria (NOB) are located in the outer layer, while denitrifying bacteria reside in the anoxic interior. AGS shares a similar stratified structure with short-cut nitrification anaerobic ammonium oxidation granular sludge, with an aerobic outer layer and an anaerobic inner layer. The anoxic / anaerobic microenvironment of AGS provides a stable living space for AnAOB, enabling its rapid colonization. Furthermore, the dense granular structure of AGS effectively retains the slow-growing AnAOB, preventing its loss.
[0006] Due to the large volume of urban wastewater, continuous flow treatment processes offer higher treatment loads and simpler operation compared to sequencing batch reactors (SBRs). Therefore, applying the PN / A process under continuous flow treatment conditions has significant practical value. This invention initiates an integrated PN / A process within a continuous flow CSTR. This is achieved by pre-inoculating aerobic granular sludge with a total sludge concentration of 4000-6000 mg / L and short-cut nitrifying anaerobic ammonium oxidation granular sludge. The natural anoxic / anaerobic microenvironment within the aerobic granular sludge guides the colonization of anaerobic ammonium oxidizing bacteria. Combined with a phased, dynamic nitrogen load enhancement strategy, the start-up cycle of the traditional PN / A process is shortened. This invention provides a theoretical basis for the efficient and stable nitrogen removal of the integrated PN / A process, offers valuable experience for its rapid start-up and stable operation, and paves the way for its widespread engineering application and promotion. Summary of the Invention
[0007] This invention relates to an apparatus and method for rapidly starting a short-cut nitrification anammox granular sludge system based on a continuous-flow stirred reactor (CSTR), belonging to the field of wastewater biological treatment technology. The apparatus includes an inlet tank, a continuous-flow stirred reactor (CSTR), and an outlet tank; the method includes "inoculation and colonization, initial operation, enrichment, and start-up steps." This invention utilizes the aerobic-anoxic-anaerobic stratified structure within the aerobic granular sludge to provide a colonization microenvironment for anammox bacteria, and promotes the enrichment of anammox bacteria through dynamic adjustment of operating parameters. This invention solves the problems of insufficient anammox seed sludge, difficulty in microbial retention and enrichment, and has advantages such as rapid start-up, stable operation, energy saving, and reduced consumption. It also has great potential and application value in the treatment of high-ammonia nitrogen wastewater.
[0008] A device for a rapid start-up short-cut nitrification anammox granular sludge system based on continuous flow CSTR is characterized by...
[0009] The equipment used includes: an inlet tank (1), a CSTR short-cut nitrification anaerobic ammonium oxidation granular sludge system (2), and an outlet tank (3).
[0010] The CSTR short-cut nitrification anaerobic ammonium oxidation granular sludge system (2) includes an air pump (2.1), a gas flow meter (2.2), a microporous aeration disc (2.3), a first peristaltic pump (2.4), a first inlet (2.5), a pH / DO meter (2.6), a stirring device (2.7), a heating device (2.8), a first outlet (2.9), a sedimentation zone (2.10), a second outlet (2.11), a third outlet (2.12), a second peristaltic pump (2.13), and a second inlet (2.14).
[0011] The high ammonia nitrogen wastewater in the inlet tank (1) is introduced in the form of artificial water distribution and pumped into the reaction zone of the CSTR reactor from the first inlet (2.5) by the first peristaltic pump (2.4); the effluent from the reaction zone flows into the sedimentation zone (2.10) through the first outlet (2.9); part of the effluent from the sedimentation zone (2.10) is pumped from the third outlet (2.12) to the second inlet (2.14) by the second peristaltic pump (2.13) and enters the reaction zone of the CSTR; the other part of the effluent from the sedimentation zone (2.10) is discharged into the outlet tank (3) through the second outlet (2.11).
[0012] A method for rapidly starting a short-cut nitrification anammox granular sludge system based on a continuous flow CSTR using the apparatus described in claim 1, characterized by comprising the following steps:
[0013] (1) Inoculation and colonization: Mixed sludge with a total sludge concentration of 4000~6000 mg / L was inoculated into the CSTR, wherein aerobic granular sludge accounted for 80%~95% of the total sludge concentration and short-cut nitrification anammox granular sludge accounted for 5%~20% of the total sludge concentration; the particle size of the inoculated aerobic granular sludge and short-cut nitrification anammox granular sludge was 200~500 μm.
[0014] (2) Initial operation: Pump high ammonia nitrogen wastewater into the reactor. The influent ammonia nitrogen concentration is 250~500 mg / L. Control the ammonia nitrogen concentration in the reactor to be 20~100 mg / L. Control the initial influent nitrogen load to be 0.1~0.3 kgN / m³ / d. The temperature in the reactor is 30~35℃, the pH is 7.5~8.0, the hydraulic retention time (HRT) is 12~24h, and the dissolved oxygen (DO) concentration is controlled at 0.3~1 mg / L.
[0015] (3) Enrichment and Start-up: When the inorganic nitrogen removal rate of the reactor reaches more than 80% for 5 consecutive days, the influent nitrogen load is gradually increased to 1.5 kgN / m³ / d by increasing it by 0.1 to 0.2 kgN / m³ / d each time. At the same time, part of the effluent from the sedimentation zone (2.10) is returned to the reaction zone through the second peristaltic pump (2.13) with a return ratio of 50% to 100% to wash the flocculent sludge. When the inorganic nitrogen removal load of the reactor reaches more than 1.0 kgN / m³ / d, the short-cut nitrification anaerobic ammonium oxidation granular sludge system is considered to have been successfully started up.
[0016] (4) Stable operation stage: After successful startup, maintain the reactor temperature at 30~35℃, pH at 7.5~8, HRT at 4~7.2h, dissolved oxygen (DO) concentration at 0.3~1mg / L, and influent nitrogen load at 1.0~1.5kgN / m³ / d for stable operation.
[0017] The beneficial effects of this invention are as follows:
[0018] (1) Rapid start-up: By using aerobic granular sludge as a carrier, the natural anoxic / anaerobic microenvironment inside the sludge is used to guide the colonization of anaerobic ammonia-oxidizing bacteria, and combined with a phased dynamic increase in nitrogen load, the system can be started up rapidly within 60 days, which greatly shortens the start-up cycle of the traditional PN / A process.
[0019] (2) High efficiency retention of microorganisms: The resulting composite granular sludge has a dense structure and good settling performance, effectively retaining slow-growing anaerobic ammonia-oxidizing bacteria, and the system has strong resistance to shock loads.
[0020] (3) Energy saving and consumption reduction: The system that is successfully started does not require an external organic carbon source and saves more than 60% of aeration energy compared with the traditional nitrification / denitrification process, while reducing the production of residual sludge.
[0021] (4) Simple operation: The device is based on a continuous flow stirred reactor, which has a simple structure and is easy to modify and apply in existing sewage treatment facilities. It is also convenient to operate and manage. Attached Figure Description
[0022] Figure 1 This is a schematic diagram of a fast-start short-cut nitrification anammox granular sludge system based on a continuous flow CSTR.
[0023] Figure 1 In the diagram: 1 – Inlet tank; 2 – Continuous flow stirred reactor CSTR short-cut nitrification anaerobic ammonia oxidation granular sludge system; 3 – Outlet tank; 2.1 – Air pump; 2.2 – Gas flow meter; 2.3 – Microporous aeration disc; 2.4 – First peristaltic pump; 2.5 – First inlet; 2.6 – pH / DO meter; 2.7 – Stirring device; 2.8 – Heating equipment; 2.9 – First outlet; 2.10 – Sedimentation zone; 2.11 – Second outlet; 2.12 – Third outlet; 2.13 – Second peristaltic pump; 2.14 – Second inlet.
[0024] Figure 2 These are effect diagrams of an embodiment of the present invention. Detailed Implementation
[0025] The embodiments of the present invention will be described in detail below with reference to the accompanying drawings and examples:
[0026] like Figure 1 As shown, the device for a rapid start-up short-cut nitrification anammox granular sludge system based on a continuous flow CSTR includes: an inlet tank (1), a continuous flow stirred reactor CSTR short-cut nitrification anammox granular sludge system (2), and an outlet tank (3).
[0027] The CSTR short-cut nitrification anaerobic ammonium oxidation granular sludge system (2) includes an air pump (2.1), a gas flow meter (2.2), a microporous aeration disc (2.3), a first peristaltic pump (2.4), a first inlet (2.5), a pH / DO meter (2.6), a stirring device (2.7), a heating device (2.8), a first outlet (2.9), a sedimentation zone (2.10), a second outlet (2.11), a third outlet (2.12), a second peristaltic pump (2.13), and a second inlet (2.14).
[0028] The high ammonia nitrogen wastewater in the inlet tank (1) is introduced in the form of artificial water distribution and pumped into the reaction zone of the CSTR from the first inlet (2.5) by the first peristaltic pump (2.4); the effluent from the reaction zone flows into the sedimentation zone (2.10) through the first outlet (2.9); part of the effluent from the sedimentation zone (2.10) is pumped from the third outlet (2.12) to the second inlet (2.14) by the second peristaltic pump (2.13) and enters the reaction zone of the CSTR reactor; the other part of the effluent from the sedimentation zone (2.10) is discharged into the outlet tank (3) through the second outlet (2.11).
[0029] A method for rapid start-up of a short-cut nitrification anaerobic ammonium oxidation granular sludge system based on continuous flow CSTR, characterized by comprising the following:
[0030] (1) Inoculation and colonization: Mixed sludge with a total sludge concentration of 4000~6000 mg / L was inoculated into the CSTR, wherein aerobic granular sludge accounted for 80%~95% of the total sludge concentration and short-cut nitrification anammox granular sludge accounted for 5%~20% of the total sludge concentration; the particle size of the inoculated aerobic granular sludge and short-cut nitrification anammox granular sludge was 200~500 μm.
[0031] (2) Initial operation: Pump high ammonia nitrogen wastewater into the reactor. The influent ammonia nitrogen concentration is 250~500 mg / L. Control the ammonia nitrogen concentration in the reactor to be 20~100 mg / L. Control the initial influent nitrogen load to be 0.1~0.3 kgN / m³ / d. The temperature in the reactor is 30~35℃, the pH is 7.5~8.0, the hydraulic retention time (HRT) is 12~24h, and the dissolved oxygen (DO) concentration is controlled at 0.3~1 mg / L.
[0032] (3) Enrichment and Start-up: When the inorganic nitrogen removal rate of the reactor reaches more than 80% for 5 consecutive days, the influent nitrogen load is gradually increased to 1.5 kgN / m³ / d by increasing it by 0.1 to 0.2 kgN / m³ / d each time. At the same time, part of the effluent from the sedimentation zone (2.10) is returned to the reaction zone through the second peristaltic pump (2.13) with a return ratio of 50% to 100% to wash the flocculent sludge. When the inorganic nitrogen removal load of the reactor reaches more than 1.0 kgN / m³ / d, the short-cut nitrification anaerobic ammonium oxidation granular sludge system is considered to have been successfully started up.
[0033] (4) Stable operation stage: After successful startup, maintain the reactor temperature at 30~35℃, pH at 7.5~8, HRT at 4~7.2h, dissolved oxygen (DO) concentration at 0.3~1mg / L, and influent nitrogen load at 1.0~1.5kgN / m³ / d for stable operation.
[0034] The specific operation steps are as follows:
[0035] (1) Inoculation sludge: Inoculate the reactor with a total concentration of 6000 mg / L of mixed sludge, of which aerobic granular sludge (particle size 250±50 μm) accounts for 95% and short-cut nitrification anaerobic ammonia oxidation granular sludge (particle size 250±50 μm) accounts for 5%.
[0036] (2) Influent and control: The influent was artificially prepared simulated high ammonia nitrogen wastewater, based on the effluent from the primary sedimentation tank of a certain wastewater treatment plant. NH4HCO3 and NaHCO3 were added to maintain the influent ammonia nitrogen concentration at 300 mg / L. The initial influent nitrogen load was controlled at 0.2 kgN / m³ / d, and the HRT was 24 h. The dissolved oxygen concentration in the reaction zone was maintained at 0.3-1.0 mg / L by adjusting the aeration rate and influent flow rate. The temperature was controlled at 30-35℃, and the pH was controlled at 7.5-8.
[0037] (3) Colonization assessment and load increase: After about 33 days of operation, a significant red fluorescent signal (AnAOB labeled by FISH technology) was observed inside the aerobic granular sludge using a laser confocal microscope. At the same time, the effluent water quality monitoring showed that the total nitrogen removal rate was stably above 60%, indicating that the anaerobic ammonia-oxidizing bacteria had successfully colonized. At this time, the influent nitrogen load was gradually increased to 1.5 kgN / m³ / d by controlling the effluent ammonia nitrogen concentration at 100 mg / L, and the second peristaltic pump (2.13) was turned on to return part of the effluent from the sedimentation zone to the reaction zone at a 50% reflux ratio to wash the flocculent sludge.
[0038] (4) Successful Start-up: On the 60th day of system operation, a large amount of mature granular sludge, visible to the naked eye and with pale yellow edges and red interior, was formed in the reactor. Monitoring data showed that the average particle size of the granular sludge increased to 476 μm, the inorganic nitrogen removal load stabilized at 1.0 kgN / m³ / d, and the inorganic nitrogen removal rate remained above 80%. At this point, the system was considered to have started up successfully. After successful start-up, the system operated stably under the conditions of a nitrogen load of 1.2 kgN / m³ / d and an HRT of 8 h.
[0039] (5) such as Figure 2 As shown, using the same reactor and influent, 95% activated sludge and 5% short-cut nitrifying anaerobic ammonium oxidation granular sludge were inoculated. Under the same operating conditions, although the inorganic nitrogen removal load reached 1 kgN / m³ / d on day 75, the reactor quickly became unstable thereafter, with an increase in effluent nitrite concentration and a subsequent decrease in inorganic nitrogen removal rate. By comparing the start-up time and denitrification performance of reactors R0 and R1, the addition of aerobic granular sludge shortened the start-up time of the integrated PN / A granular sludge reactor by 20%, and the reactor did not exhibit phenomena such as an increase in effluent nitrite concentration, indicating stable reactor operation.
[0040] The above are specific embodiments of the present invention, which enable those skilled in the art to better understand and apply the present invention. However, the implementation of the present invention is not limited thereto. Therefore, any simple improvements made to the present invention by those skilled in the art are within the protection scope of the present invention.
Claims
1. A device for a rapid start-up short-cut nitrification anammox granular sludge system based on continuous flow CSTR, characterized in that, include: Inlet tank (1), CSTR short-cut nitrification anaerobic ammonium oxidation granular sludge system (2), outlet tank (3); The CSTR short-cut nitrification anaerobic ammonium oxidation granular sludge system (2) includes an air pump (2.1), a gas flow meter (2.2), a microporous aeration disc (2.3), a first peristaltic pump (2.4), a first inlet (2.5), a pH / DO meter (2.6), a stirring device (2.7), a heating device (2.8), a first outlet (2.9), a sedimentation zone (2.10), a second outlet (2.11), a third outlet (2.12), a second peristaltic pump (2.13), and a second inlet (2.14). The high ammonia nitrogen wastewater in the inlet tank (1) is introduced in the form of artificial water distribution and pumped into the reaction zone of CSTR from the first inlet (2.5) by the first peristaltic pump (2.4); the effluent from the reaction zone flows into the sedimentation zone (2.10) through the first outlet (2.9); part of the effluent from the sedimentation zone (2.10) is pumped from the third outlet (2.12) to the second inlet (2.14) by the second peristaltic pump (2.13) and enters the reaction zone of CSTR; the other part of the effluent from the sedimentation zone (2.10) is discharged into the outlet tank (3) through the second outlet (2.11).
2. A method for rapidly starting a short-cut nitrification anammox granular sludge system based on a continuous flow CSTR using the apparatus described in claim 1, characterized in that, Includes the following steps: (1) Inoculation and colonization: Mixed sludge with a total sludge concentration of 4000~6000 mg / L was inoculated into the CSTR, wherein aerobic granular sludge accounted for 80%~95% of the total sludge concentration and short-cut nitrification anammox granular sludge accounted for 5%~20% of the total sludge concentration; the particle size of the inoculated aerobic granular sludge and short-cut nitrification anammox granular sludge was 200~500 μm. (2) Initial operation: Pump high ammonia nitrogen wastewater into the reactor. The influent ammonia nitrogen concentration is 250~500 mg / L, and the ammonia nitrogen concentration in the reactor is controlled at 20~100 mg / L. The initial influent nitrogen load is controlled at 0.1~0.3 kgN / m³ / d, the temperature in the reactor is 30~35℃, the pH is 7.5~8.0, the hydraulic retention time (HRT) is 12~24 h, and the dissolved oxygen (DO) concentration is controlled at 0.3~1 mg / L. (3) Enrichment and Start-up: When the inorganic nitrogen removal rate of the reactor reaches more than 80% for 5 consecutive days, the influent nitrogen load is gradually increased to 1.5 kgN / m³ / d by increasing it by 0.1 to 0.2 kgN / m³ / d each time. At the same time, part of the effluent from the sedimentation zone (2.10) is returned to the reaction zone through the second peristaltic pump (2.13) with a return ratio of 50% to 100% to wash the flocculent sludge. When the inorganic nitrogen removal load of the reactor reaches more than 1.0 kgN / m³ / d, the short-cut nitrification anaerobic ammonium oxidation granular sludge system is considered to have been successfully started up. (4) Stable operation stage: After successful startup, maintain the reactor temperature at 30~35℃, pH at 7.5~8, HRT at 4~7.2h, dissolved oxygen concentration at 0.3~1mg / L, and influent nitrogen load at 1.0~1.5kgN / m³ / d.