Method for enhancing denitrification performance of a powder carrier process based on intermittent aeration

Abstract

This invention relates to a method for enhancing the nitrogen removal performance of a powder carrier process based on intermittent aeration. The method is implemented using a powder carrier system, which includes an influent subsystem (1), a main reactor (2), an effluent subsystem (3), and a carrier recovery subsystem (4). After actual wastewater enters the system, powder carriers with a particle size of 20–200 micrometers are added to the main reactor. The powder carrier process is operated using an anaerobic stirring + intermittent aeration stirring mode (aeration / stop time = 0.5–0.75). Compared with existing technologies, this invention, through the addition of powder carriers and intermittent aeration, stably cultivates microparticle sludge, increases microbial biomass, and effectively enhances the ammonia oxidation rate and denitrification rate. It also directionally enriches ammonia-oxidizing bacteria and denitrifying bacteria, realizing short-cut nitrification and denitrification processes as well as simultaneous nitrification and denitrification, thus enhancing the wastewater nitrogen removal performance of the powder carrier process and having broad application prospects.

Description

Technical Field

[0001] This invention relates to the field of wastewater denitrification technology, and in particular to a method for enhancing the denitrification performance of a powder carrier process based on intermittent aeration. Background Technology

[0002] Wastewater treatment capacity has been significantly improved, and the discharge of various pollutants has been effectively reduced. The 2022 national surface water quality report shows that among 3,641 national surface water assessment sections, Class IV and V water bodies accounted for 12.1%; and among 204 lakes and reservoirs monitored for trophic status, eutrophication accounted for 29.9%. This indicates that eutrophication caused by excessive nitrogen and phosphorus emissions remains one of the most serious water pollution problems facing my country at present. Reducing the total nitrogen concentration in wastewater is both a key focus and a challenge. Therefore, addressing the problems of low operating loads, excessive nitrogen and phosphorus levels in effluent, and the need for external carbon sources in existing wastewater treatment plants, this report proposes new technologies for upgrading and transforming wastewater treatment plants to achieve deep pollutant reduction and low-consumption operation. This is of great significance for preventing and controlling water pollution and ensuring national water resources and water ecological security.

[0003] Powder carrier technology is a novel wastewater treatment technology that improves wastewater treatment performance by adding powder carriers to a biochemical reactor to rapidly enrich microorganisms and form micro-particle sludge. However, current methods primarily rely on increasing the number of microorganisms to enhance treatment efficiency. A key challenge is how to improve the biochemical reaction rate of functional microorganisms and selectively enrich denitrifying microorganisms within the powder carrier process to further enhance denitrification performance. Summary of the Invention

[0004] The purpose of this invention is to overcome the defects of the prior art by providing a method for enhancing the denitrification performance of a powder carrier process based on intermittent aeration. This method is simple to operate. By adding powder carrier and adjusting the aeration mode, the biochemical reaction activity of ammonia-oxidizing bacteria and denitrifying bacteria is enhanced, and ammonia-oxidizing bacteria and denitrifying bacteria are selectively enriched. This promotes short-cut nitrification and denitrification and simultaneous nitrification and denitrification processes, thereby improving the biological denitrification performance of wastewater.

[0005] The objective of this invention can be achieved through the following technical solutions:

[0006] The purpose of this invention is to provide a method for enhancing the denitrification performance of a powder carrier process based on intermittent aeration, wherein the method is implemented based on a powder carrier system;

[0007] The method includes the following steps:

[0008] Sludge is inoculated into the main reactor. After inoculation, the sludge concentration MLSS is 3500-5000 mg / L. After the sludge inoculation is completed, water is fed into the main reactor through the water inlet subsystem. The water inlet time is 5 minutes, wastewater is used, and the operating temperature is 15-30℃.

[0009] Then, powdered carrier is added to the main reactor at a dosage of 1.5–2.5 g / L. The system is operated with anaerobic stirring and intermittent aeration stirring to carry out biological denitrification of wastewater. During the aeration stage, the dissolved oxygen concentration is maintained at 1.0–2.0 mg / L. The wastewater is discharged into the effluent subsystem, with a sedimentation and discharge time of 30 min, a discharge ratio of 40%–70%, and the sludge age is controlled at 15–25 days.

[0010] During the aeration stage, the carrier recovery subsystem is activated. After the carrier recovery subsystem separates the sludge-water mixture, the powdered carrier is returned to the main reactor, and the remaining sludge is discharged from the system.

[0011] Furthermore, the powder carrier system includes an inlet subsystem, a main reactor, an outlet subsystem, and a carrier recovery subsystem; the inlet subsystem is connected to the main reactor; the outlet subsystem is connected to the main reactor; and the carrier recovery subsystem is connected to the main reactor.

[0012] Furthermore, the water inlet subsystem includes an inlet tank and peristaltic pump I; the main reactor includes a main reactor body, which is equipped with a stirring device, an air pump, a gas flow meter, an aeration disc, an online dissolved oxygen / temperature monitor, an inlet, an outlet I, an outlet II, an overflow outlet, and a drain outlet; the water outlet subsystem includes an outlet solenoid valve and an outlet water tank; the carrier recovery subsystem includes a hydrocyclone separator, peristaltic pump II, and a peristaltic pump III.

[0013] Furthermore, the peristaltic pump I is connected to the inlet via a pipeline; the air pump is connected to the gas flow meter; the gas flow meter is connected to the aeration disc; the water solenoid valve is connected to the outlet I; the effluent pool is connected to the water solenoid valve; the hydrocyclone separator is connected to the main reactor body via the peristaltic pump II; and the hydrocyclone separator is connected to the main reactor body via the peristaltic pump III.

[0014] Furthermore, the anaerobic stirring + intermittent aeration stirring refers to anaerobic stirring followed by intermittent aeration stirring.

[0015] Furthermore, in the steps of the method:

[0016] During the aeration stage, the carrier recovery subsystem is activated. Peristaltic pump II transports the sludge-water mixture to the hydrocyclone separator. After separation, the powdered carrier is returned to the main reactor by peristaltic pump III, and the remaining sludge is discharged from the system.

[0017] Furthermore, the operating speed of the hydrocyclone separator is 230–300 r / min, and the cyclone separation time is 1.5–3 min.

[0018] Furthermore, the anaerobic stirring time is 90 minutes, including a 5-minute water inlet time; the intermittent aeration stirring time is 240 minutes.

[0019] Furthermore, the sludge is suspended sludge from the aerobic zone of the wastewater treatment plant; the powder carrier is diatomaceous earth powder carrier; and the wastewater is actual domestic sewage.

[0020] Furthermore, the actual domestic sewage has a chemical oxygen demand of 150 mg / L to 250 mg / L and a total nitrogen of 30 mg / L to 60 mg / L.

[0021] Furthermore, the intermittent aeration operates in the form of aeration followed by aeration stop, and undergoes multiple aeration and aeration stop cycles. The ratio of aeration to aeration stop time in the intermittent aeration stage is 0.5 to 0.75.

[0022] Furthermore, the particle size of the powder carrier is 20–200 micrometers.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] The present invention proposes a method for enhancing the denitrification performance of powder carrier process based on intermittent aeration. In practical applications, it is simple to operate and convenient to run. It can be achieved simply by changing the aeration mode and setting the aeration stop ratio in the existing powder carrier process.

[0025] After the formation of micro-particle sludge under the action of powder carrier, intermittent aeration can further screen ammonia-oxidizing bacteria and inhibit nitrite-oxidizing bacteria, thereby achieving the targeted enrichment of denitrification functional bacteria, promoting the occurrence of short-cut nitrification and denitrification and simultaneous nitrification and denitrification, thus enhancing the denitrification performance of wastewater and achieving deep reduction of pollutants. It has broad application prospects. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the powder carrier system for the method of enhancing the denitrification performance of powder carrier process based on intermittent aeration according to the present invention.

[0027] In the picture:

[0028] 1 – Inlet subsystem, 2 – Main reactor, 3 – Outlet subsystem, 4 – Carrier recovery subsystem, 1.1 – Inlet tank, 1.2 – Peristaltic pump I, 2.1 – Stirring device, 2.2 – Air pump, 2.3 – Gas flow meter, 2.4 – Aeration disc, 2.5 – Dissolved oxygen / temperature online monitor, 2.6 – Inlet, 2.7 – Outlet I, 2.8 – Outlet II, 2.9 – Overflow port, 2.10 – Drain port, 3.1 – Outlet solenoid valve, 3.2 – Outlet tank, 4.1 – Hydrocyclone separator, 4.2 – Peristaltic pump II, 4.3 – Peristaltic pump III. Detailed Implementation

[0029] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. Component models, material names, connection structures, control methods, and other features not explicitly described in this technical solution are considered common technical features disclosed in the prior art.

[0030] This invention belongs to the field of wastewater denitrification technology, specifically a method for enhancing the denitrification performance of a powder carrier process based on intermittent aeration. The process used is a powder carrier process, including an influent subsystem, a main reactor, an effluent subsystem, and a carrier recovery subsystem. After actual wastewater enters the system, powder carriers with a particle size of 20–200 micrometers are added to the main reactor, and the powder carrier process is operated in an anaerobic stirring / intermittent aeration stirring mode (aeration / stop time = 0.5–0.75). This invention, through the addition of powder carriers and intermittent aeration, stably cultivates microparticle sludge, increases microbial biomass while effectively enhancing the ammonia oxidation and denitrification rates, directionally enriches ammonia-oxidizing bacteria and denitrifying bacteria, realizes short-cut nitrification-denitrification and simultaneous nitrification-denitrification processes, and enhances the wastewater denitrification performance of the powder carrier process, showing broad application prospects.

[0031] Example

[0032] like Figure 1As shown, a method for enhancing the denitrification performance of a powder carrier process based on intermittent aeration is disclosed. The process used is a powder carrier process, and the method is implemented based on a powder carrier system. The powder carrier system includes an influent subsystem 1, a main reactor 2, an effluent subsystem 3, and a carrier recovery subsystem 4. The influent subsystem 1 is connected to the main reactor 2. The effluent subsystem 3 is connected to the main reactor 2. The carrier recovery subsystem 4 is connected to the main reactor 2. The influent subsystem 1 includes an influent tank 1.1 and a peristaltic pump 1.2. The main reactor 1... The reactor 2 is equipped with a stirring device 2.1, an air pump 2.2, a gas flow meter 2.3, an aeration disc 2.4, an online dissolved oxygen / temperature monitor 2.5, an inlet 2.6, an outlet I 2.7, an outlet II 2.8, an overflow outlet 2.9, and a drain outlet 2.10; the effluent subsystem 3 is equipped with an effluent solenoid valve 3.1 and an effluent pool 3.2; the carrier recovery subsystem 4 includes a hydrocyclone separator 4.1, a peristaltic pump II 4.2, and a peristaltic pump III 4.3; the main reactor is made of plexiglass and has an effective volume of 2L.

[0033] The peristaltic pump I 1.2 is connected to the inlet 2.6 via a pipeline; the air pump 2.2 is connected to the gas flow meter 2.3; the gas flow meter 2.3 is connected to the aeration disc 2.4; the water solenoid valve 3.1 is connected to the outlet I 2.7; the effluent pool 3.2 is connected to the water solenoid valve 3.1; the hydrocyclone separator 4.1 is connected to the main reactor body via the peristaltic pump II 4.2; the hydrocyclone separator 4.1 is connected to the main reactor body via the peristaltic pump III 4.3.

[0034] The method includes the following steps:

[0035] The inoculated sludge was taken from the suspended sludge of the aerobic zone of the biochemical treatment unit of a wastewater treatment plant in Shanghai. After inoculation, the sludge concentration (MLSS) in the system was 4000±75 mg / L. The influent was actual domestic sewage, taken from the septic tank of Tongji University's residential area. The influent time was 5 minutes, and the influent water quality characteristics were: chemical oxygen demand (COD) 178±25 mg / L, total nitrogen 39±14 mg / L, and the operating temperature was room temperature (18~29℃).

[0036] Diatomaceous earth powder carrier was added to the main reactor (2) at a dosage of 2.0 g / L, and the diatomaceous earth particle size was 75-150 micrometers.

[0037] After sludge inoculation, the system was operated using anaerobic stirring / intermittent aeration (90 min (including 5 min of influent time, i.e., the system started operating at the beginning of influent) / 240 min) to biologically denitrify actual domestic sewage. The intermittent aeration process involved aeration / stop time of 30 min / 50 min, with a total of three aeration and stop cycles. During the aeration phase, the dissolved oxygen concentration was maintained at 1.0–2.0 mg / L. The sedimentation and drainage time was 30 min, the drainage ratio was 50%, and the sludge age was controlled at 20 days. The stirring rate for both anaerobic and intermittent aeration was 180 r / min. During the third intermittent aeration phase, peristaltic pump II 4.2 was activated to transport 200 mL of the sludge-water mixture to the hydrocyclone separator 4.1. After cyclone separation at 250 r / min for 2 min, 100 mL of the upper mixed liquid was returned to the main reactor 2 by peristaltic pump III 4.3, while the remaining 100 mL of the mixed liquid at the bottom was discharged from the system.

[0038] Meanwhile, a control group was set up, which used the same anaerobic / aerobic / hypoxic (90min / 90min / 150min) operating mode as the above implementation plan, except that other conditions were the same.

[0039] The experimental results show that after 50 days of system operation (calculated from the start of sludge inoculation), the control group using the anaerobic + aerobic + anoxic (90min / 90min / 150min) operation mode achieved a COD removal rate of over 90% and a total nitrogen removal rate of over 70%. In contrast, the experimental group (example) based on intermittent aeration showed that the ammonia oxidation rate and denitrification rate increased by 34% and 25%, respectively, with a COD removal rate of over 95% and a total nitrogen removal rate of over 90%, meeting the national Class A effluent discharge standard.

[0040] The above description of the embodiments is provided to enable those skilled in the art to understand and use the invention. It will be apparent to those skilled in the art that various modifications can be made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present invention is not limited to the above embodiments, and any improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the invention should be within the protection scope of the present invention.

Claims

1. A method for enhancing the denitrification performance of a powder carrier process based on intermittent aeration, characterized in that, The method is implemented based on a powder carrier system; The powder carrier system includes an inlet subsystem (1), a main reactor (2), an outlet subsystem (3), and a carrier recovery subsystem (4). The water intake subsystem (1) is connected to the main reactor (2); The effluent subsystem (3) is connected to the main reactor (2); The carrier recovery subsystem (4) is connected to the main reactor (2); The method includes the following steps: Sludge is inoculated into the main reactor (2). After inoculation, the sludge concentration MLSS is 3500~5000mg / L. After the sludge inoculation is completed, water is fed into the main reactor (2) through the water inlet subsystem (1). The water inlet time is 5min. Wastewater is used for the water inlet. The operating temperature is 15~30℃. Powdered carrier was added to the main reactor (2) at a dosage of 1.5~2.5 g / L. The system was operated in an anaerobic stirring + intermittent aeration stirring mode to carry out biological denitrification of the wastewater. The anaerobic stirring time was 90 min, including the influent time of 5 min. The intermittent aeration stirring time was 240 min. The intermittent aeration stirring process alternated between aeration / stop time of 30 min / 50 min and went through a total of 3 aeration and stop times. The dissolved oxygen concentration was maintained at 1.0~2.0 mg / L during the aeration stage. During the third aeration stage of the intermittent aeration and stirring process, the carrier recovery subsystem (4) is started to transport the mud-water mixture to the hydrocyclone separator (4.1) for cyclone separation. After cyclone separation, the powder carrier is returned to the main reactor (2), and the remaining sludge is discharged from the system. The wastewater enters the effluent subsystem (3), the sedimentation and drainage time is 30 min, the drainage ratio is 40%~70%, and the sludge age is controlled at 15~25 days.

2. The method for enhancing the denitrification performance of a powder carrier process based on intermittent aeration according to claim 1, characterized in that, The water intake subsystem (1) includes an intake pool (1.1) and a peristaltic pump I (1.2). The main reactor (2) includes a main reactor body, which is equipped with a stirring device (2.1), an air pump (2.2), a gas flow meter (2.3), an aeration disc (2.4), an online dissolved oxygen / temperature monitor (2.5), an inlet (2.6), an outlet I (2.7), an outlet II (2.8), an overflow outlet (2.9), and an exhaust outlet (2.10). The water outlet subsystem (3) includes a water outlet solenoid valve (3.1) and a water outlet pool (3.2). The carrier recovery subsystem (4) includes a hydrocyclone separator (4.1), a peristaltic pump II (4.2), and a peristaltic pump III (4.3).

3. The method for enhancing the denitrification performance of a powder carrier process based on intermittent aeration according to claim 2, characterized in that, The peristaltic pump I (1.2) is connected to the inlet (2.6) via a pipeline; The air pump (2.2) is connected to the gas flow meter (2.3); The gas flow meter (2.3) is connected to the aeration disc (2.4); The water outlet solenoid valve (3.1) is connected to the water outlet I (2.7); The outlet water tank (3.2) is connected to the outlet solenoid valve (3.1); The hydrocyclone separator (4.1) is connected to the main reactor body via peristaltic pump II (4.2); The hydrocyclone separator (4.1) is connected to the main reactor body via a peristaltic pump Ⅲ (4.3).

4. The method for enhancing the denitrification performance of a powder carrier process based on intermittent aeration according to claim 3, characterized in that, In the steps of the method: During the third aeration stage of the intermittent aeration and stirring process, the carrier recovery subsystem (4) is started. Peristaltic pump II (4.2) transports the mud-water mixture to the hydrocyclone separator (4.1). After separation, the powder carrier is returned to the main reactor (2) by peristaltic pump III (4.3), and the remaining sludge is discharged from the system.

5. The method for enhancing the denitrification performance of a powder carrier process based on intermittent aeration according to claim 4, characterized in that, The hydrocyclone separator (4.1) operates at a speed of 230~300 r / min and a separation time of 1.5~3 min.

6. The method for enhancing the denitrification performance of a powder carrier process based on intermittent aeration according to claim 1, characterized in that, The sludge is suspended sludge from the aerobic zone of the wastewater treatment plant. The powder carrier is a diatomaceous earth powder carrier; The wastewater in question is actual domestic sewage.

7. The method for enhancing the denitrification performance of a powder carrier process based on intermittent aeration according to claim 6, characterized in that, The actual domestic sewage has a chemical oxygen demand of 150 mg / L to 250 mg / L and a total nitrogen of 30 mg / L to 60 mg / L.

8. The method for enhancing the denitrification performance of a powder carrier process based on intermittent aeration according to claim 1, characterized in that, The particle size of the powder carrier is 20~200 micrometers.

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