A method for enhancing the performance of short-cut nitrification-anaerobic ammonia oxidation multi-pathway denitrification by short-term exogenous addition of AHLs type signal molecules

Abstract

The application discloses a method for strengthening short-cut nitrification-anaerobic ammonia oxidation multi-pathway denitrification performance by short-term exogenous addition of AHLs signal molecules, and belongs to the technical field of sewage biological treatment. The method comprises the following steps: (1) inoculating suspended filler with a biofilm into a short-cut nitrification-anaerobic ammonia oxidation system; (2) mixing AHLs signal molecules with artificial water to enter the short-cut nitrification-anaerobic ammonia oxidation system, starting and running the short-cut nitrification-anaerobic ammonia oxidation system; (3) running the short-cut nitrification-anaerobic ammonia oxidation system by adopting a low-oxygen and intermittent aeration strategy; and (4) adopting a sequencing batch reaction, and each running cycle comprises water feeding, pre-anoxic stirring, intermittent aeration, sedimentation, water draining and idling. The application takes high-ammonia-nitrogen wastewater with a low C / N ratio as a substrate, artificially controls group sensing among functional bacteria in the system by short-term exogenous addition of AHLs signal molecules, and strengthens nitrogen removal performance of the short-cut nitrification-anaerobic ammonia oxidation multi-pathway denitrification system.

Description

Technical Field

[0001] This invention relates to the field of wastewater treatment technology, specifically to a method for enhancing short-range nitrification-anaerobic ammonium oxidation denitrification performance by short-term exogenous addition of AHLs-type signaling molecules. Background Technology

[0002] Anaerobic ammonia oxidation (AAO) is a novel, highly efficient, and energy-saving biological nitrogen removal process. Compared with traditional nitrification-denitrification processes, it offers advantages such as reduced aeration, no need for organic carbon sources, and lower sludge production. Combined processes based on AAO, especially the integrated partial nitritation-anammox (PNA) process coupling multiple nitrogen removal pathways, have attracted widespread attention from scholars both domestically and internationally. In this process, ammonia-oxidizing bacteria, nitrite-oxidizing bacteria, anaerobic ammonia-oxidizing bacteria, and denitrifying bacteria coexist. For integrated PNA processes, dissolved oxygen concentration is a key control parameter, and currently, most systems operate in a low dissolved oxygen mode. Maintaining a low dissolved oxygen concentration in the integrated PNA system, while effectively inhibiting the activity of nitrite-oxidizing bacteria, also limits the activity of ammonia-oxidizing bacteria, making ammonia oxidation the rate-limiting step in nitrogen removal and thus affecting the nitrogen removal performance of the integrated PNA system. However, increasing the dissolved oxygen concentration risks promoting nitrate formation and inhibiting the activity of anaerobic ammonia-oxidizing bacteria, reducing the overall nitrogen removal efficiency of the system. Therefore, under low dissolved oxygen operating conditions, it is particularly important to rationally regulate various denitrifying bacteria with different physiological and metabolic characteristics and improve the nitrogen removal performance of integrated PNA multi-pathway denitrification systems. Quorum sensing is a regulatory system among microorganisms that regulates gene expression and physiological behavior, and is therefore called the "communication language" among microorganisms. The vast majority of microorganisms involved in wastewater biological treatment are Gram-negative bacteria, and the quorum sensing system of Gram-negative bacteria is mainly mediated by N-acyl-homoserne-lactones (AHLs) signaling molecules. In integrated PNA systems, the cooperation and competition among ammonia-oxidizing bacteria, nitrite-oxidizing bacteria, denitrifying bacteria, and anaerobic ammonia-oxidizing bacteria usually rely on intercellular communication. More and more researchers are beginning to focus on the impact of AHLs-mediated quorum sensing on the regulation of wastewater treatment performance, and these studies provide a new perspective and theoretical support for improving the pollutant removal performance of integrated PNA systems with multi-pathway denitrification. Based on the above background, the present invention aims to study a method for enhancing the multi-pathway denitrification performance of a short-range nitrification-anaerobic ammonium oxidation system by short-term exogenous addition of AHLs-type signaling molecules. Summary of the Invention

[0003] This invention addresses the problems of unstable performance and complex regulation of short-cut nitrification-anaerobic ammonium oxidation (ATO) multi-pathway nitrogen removal in existing technologies. It provides a method for enhancing the nitrogen removal performance of short-cut nitrification-ATO multi-pathway nitrogen removal through short-term exogenous addition of AHL-like signaling molecules. Under hypoxic, intermittent aeration conditions, this method artificially regulates quorum sensing among microorganisms by exogenously adding AHL-like signaling molecules, influencing the metabolic activity of denitrifying bacteria in the short-cut nitrification-anaerobic ammonium oxidation system, thereby improving the system's nitrogen removal efficiency.

[0004] The present invention provides a method for enhancing the performance of short-range nitrification-anaerobic ammonium oxidation multi-pathway nitrogen removal by short-term exogenous addition of AHL-type signaling molecules, which specifically includes the following steps:

[0005] (1) Inoculate the suspended packing material with attached biofilm into the short-cut nitrification-anaerobic ammonium oxidation system, with the filling volume ratio of the suspended packing material being 40% to 50%.

[0006] (2) Operation of short-cut nitrification-anaerobic ammonium oxidation system

[0007] Artificially prepared water is used as the influent substrate. The influent water quality is as follows: ammonia nitrogen concentration is 200 mg / L, chemical oxygen demand (COD) is 200 mg / L, and C / N ratio is 1. The COD is provided by sodium acetate and glucose in a ratio of sodium acetate: glucose = 1:1.

[0008] AHL-type signaling molecules are added to the short-cut nitrification-anaerobic ammonia oxidation system by mixing with artificially prepared water to enhance the activity of denitrifying bacteria.

[0009] The sequential batch reactor is used, and the single-cycle operation mode is as follows: water inlet time 5 min, water inlet flow rate 0.1 L / min, pre-anoxic stirring time 120 min, intermittent aeration time 780-960 min, aeration rate 0.1 L / min, settling time 2 min, drainage time 3 min, idle time 350-530 min, and drainage ratio of 50%.

[0010] Preferably, the short-range nitrification-anaerobic ammonium oxidation system described in step (2) operates at a temperature of 30±2℃ and is operated in the dark.

[0011] Preferably, the AHLs signaling molecules mentioned in step (2) are C6-HSL signaling molecules, C10-HSL signaling molecules or 3-oxo-C12-HSL signaling molecules, with an addition concentration of 10 to 100 nmol / L, and are added for a total of 8 cycles.

[0012] Preferably, the intermittent aeration operation mode described in step (2) is aerobic aeration: anoxic stirring = 30:30min.

[0013] Preferably, the aerobic aeration maintains a dissolved oxygen concentration of 0.3–0.5 mg / L within the short-cut nitrification-anaerobic ammonia oxidation system during the aeration process.

[0014] This invention patent intervenes in the microbial growth and quorum sensing of a short-range nitrification-anaerobic ammonia oxidation system by short-term exogenous addition of C6-HSL signaling molecules, C10-HSL signaling molecules and 3-oxo-C12-HSL signaling molecules, thereby improving the metabolic activity of denitrifying bacteria in the system and thus improving the nitrogen removal rate of the system.

[0015] Compared with the prior art, this invention patent has the following advantages and beneficial effects:

[0016] (1) This invention can significantly improve the activity of denitrifying bacteria in a short-range nitrification-anaerobic ammonia oxidation system without changing the original operating mode by adding AHLs signaling molecules for a short period of time, thereby achieving a rapid improvement in the denitrification performance of the system.

[0017] (2) The present invention adopts a low dissolved oxygen operation strategy, the concentration of AHLs signal molecules is low and no external organic carbon source is required during operation, resulting in low operating energy consumption and saving operating costs.

[0018] (3) The present invention is simple to operate and has the advantage of being applicable to both pure anaerobic ammonium oxidation system and short-cut nitrification-anaerobic ammonium oxidation multi-pathway denitrification system, and has a wide range of applications. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the facility structure used in this invention;

[0020] In the diagram: 1. Water distribution tank; 2. Peristaltic pump; 3. Inlet; 4. Signal molecule storage bottle; 5. Metering pump; 6. Electric drain valve; 7. Drain tank; 8. Electric stirrer; 9. Short-cut nitrification-anaerobic ammonia oxidation reactor; 10. Heating tape; 11. Gas flow meter; 12. Aeration pump; 13. Microporous aeration disc; 14. Time controller. Detailed Implementation

[0021] The present invention will be further described in detail below with reference to the embodiments and accompanying drawings, but the implementation of the present invention is not limited thereto.

[0022] The device used in this invention is as follows Figure 1As shown. The artificially simulated wastewater in the water distribution tank 1 and the signal molecule reserve liquid in the signal molecule reserve bottle 4 are pumped out by the peristaltic pump 2 and the metering pump 5, respectively. The peristaltic pump 2 and the metering pump 5 are connected to the water distribution tank 1, the signal molecule reserve bottle 4, and the inlet 3 of the short-cut nitrification-anammox reactor 9 via rubber hoses. The aeration pump 12 is connected to the gas flow meter 11 via a rubber hose, and the gas flow meter 11 is connected to the microporous aeration disc 13 at the bottom of the short-cut nitrification-anammox reactor 9 via a rubber hose. The short-cut nitrification-anammox reactor 9 is equipped with an electric drain valve 6 on its side, which is connected to the drain tank 7 via a rubber hose. The top of the short-cut nitrification-anammox reactor 9 is equipped with an electric stirrer 8 for fluidizing the packing and for adjusting the temperature by wrapping the outer wall with a heating tape 10. The drainage ratio of the short-cut nitrification-anammox reactor 9 is 50%. The output of the time controller 14 is connected to the input of the peristaltic pump 2, the metering pump 5, the electric drain valve 6, the electric agitator 8, the heat tracing cable 10, and the aeration pump 12 via wires.

[0023] This invention enhances the performance of short-range nitrification-anaerobic ammonium oxidation multi-pathway nitrogen removal by short-term exogenous addition of AHL-type signaling molecules, specifically including the following steps:

[0024] (1) The short-cut nitrification-anaerobic ammonium oxidation reactor 9 adopts a sequencing batch reactor with an effective volume of 1L. The material is plexiglass. The filling volume ratio of the inoculated suspended packing is 40% to 50% of the short-cut nitrification-anaerobic ammonium oxidation reactor 9. The reactor operating temperature is controlled at 30±2℃ by the heating tape 10. It is operated in the dark, with a hydraulic retention time of 48h and a effluent ratio of 50%.

[0025] (2) The artificially prepared water in water tank 1 mainly consists of ammonium chloride, glucose, and sodium acetate, while also providing inorganic salts and trace elements required for microbial growth. The specific components and concentrations of the influent are shown in Table 1 below.

[0026] Table 1: Water Quality Characteristics

[0027]

[0028]

[0029] (3) The artificially prepared water and signal molecule reserve liquid in the water distribution tank 1 and the signal molecule reserve bottle 4 are pumped into the short-cut nitrification-anaerobic ammonia oxidation reactor 9 through the peristaltic pump 2 and the metering pump 5, respectively, so that the concentration of AHLs signal molecules in the final reaction volume reaches 20 nmol / L.

[0030] (4) After artificial water distribution and AHLs signal molecules are introduced, the electric agitator 8 is turned on for 120 minutes of pre-anoxic stirring. Then, the aeration pump 12 is turned on for 780-960 minutes of intermittent aeration. The intermittent aeration operation mode is aerobic aeration: anoxic stirring = 30:30 min. During the aerobic aeration stage, the dissolved oxygen concentration in the short-cut nitrification-anaerobic ammonia oxidation reactor 9 is maintained at 0.3-0.5 mg / L by the gas flow meter 11. After the reaction is completed and there is a 2-minute settling period, the electric drain valve 6 is opened to drain water for 3 minutes. The remaining time is a 350-530 minute idle time.

[0031] (5) After the 8th cycle, the total nitrogen removal rate of the short-cut nitrification-anaerobic ammonium oxidation reactor 9 was tested, and an appropriate amount of biological packing material was taken from the short-cut nitrification-anaerobic ammonium oxidation reactor 9 for functional bacteria activity test.

[0032] Example 1:

[0033] According to the above experimental system parameters and environmental conditions, 40 nmol / L of C6-HSL signaling molecules were added to the short-cut nitrification-anaerobic ammonium oxidation reactor. After 8 cycles of operation, compared with the control group without exogenous addition of AHLs signaling molecules, the total nitrogen removal rate increased by 5.60%, and the activities of ammonia-oxidizing bacteria, anaerobic ammonium-oxidizing bacteria, and denitrifying bacteria increased by 8.53%, 28.90%, and 12.66%, respectively, successfully enhancing the nitrogen removal efficiency of the short-cut nitrification-anaerobic ammonium oxidation system.

[0034] Example 2:

[0035] The experimental system parameters and environmental conditions were the same as in Example 1, with 40 nmol / L of C10-HSL signaling molecules added to the short-cut nitrification-anaerobic ammonium oxidation reactor. After 8 cycles of operation, compared with the control group without exogenous addition of AHLs signaling molecules, the total nitrogen removal rate increased by 9.07%, and the activity of anaerobic ammonium oxidizing bacteria increased by 21.50%. The nitrogen removal efficiency of the multi-pathway denitrification short-cut nitrification-anaerobic ammonium oxidation system was successfully enhanced.

[0036] Example 3:

[0037] The experimental parameters and environmental conditions were the same as in Example 1, with 40 nmol / L of 3-oxo-C12-HSL signaling molecules added to the short-cut nitrification-anaerobic ammonium oxidation reactor. After 8 cycles of operation, compared with the control group without exogenous addition of AHLs signaling molecules, the total nitrogen removal rate increased by 8.34%, and the activities of ammonia oxidizing bacteria and anaerobic ammonium oxidizing bacteria increased by 2.04% and 14.25%, respectively. The nitrogen removal efficiency of the short-cut nitrification-anaerobic ammonium oxidation system was successfully enhanced.

[0038] It should be noted that the embodiments described in the specification are all preferred embodiments, and the same or similar parts between embodiments can be referred to mutually. Those skilled in the art, under the guidance of this invention, can make many other modifications without departing from the spirit and scope of the claims, and all of these are within the protection scope of this invention.

Claims

1. A method for enhancing the performance of short-range nitrification-anaerobic ammonium oxidation multi-pathway nitrogen removal by short-term exogenous addition of AHL-type signaling molecules, characterized in that, The method includes the following steps: (1) Inoculate pre-film-coated suspended packing material into a short-cut nitrification-anaerobic ammonium oxidation system, with the volume ratio of suspended packing material being 40%~50%; (2) Operation of a short-cut nitrification-anaerobic ammonium oxidation system: Artificially prepared water was used as the influent substrate. The influent water quality was as follows: ammonia nitrogen concentration of 200 mg / L, chemical oxygen demand (COD) of 200 mg / L, and C / N ratio of 1. AHL-type signaling molecules are added to the short-cut nitrification-anaerobic ammonium oxidation system by mixing with artificial water to enhance the activity of denitrifying bacteria. The sequencing batch reactor (SBR) is used, and the single-cycle operation mode is as follows: influent time 5 min, influent flow rate 0.1 L / min, pre-anoxic stirring time 120 min, intermittent aeration time 780~960 min, aeration rate 0.1 L / min, settling time 2 min, drainage time 3 min, idle time 350~530 min, and drainage ratio 50%. In step (2), the operating temperature of the short-cut nitrification-anaerobic ammonium oxidation system is 30±2 ℃, and it is operated in the dark. In step (2), the types of AHLs signaling molecules are C6-HSL signaling molecules, C10-HSL signaling molecules or 3-oxo-C12-HSL signaling molecules, and the dosage of AHLs signaling molecules is 10~100 nmol / L. In step (2), the intermittent aeration operation mode is aerobic aeration: anoxic stirring = 30:30 min; Aerobic aeration maintains the dissolved oxygen concentration in the short-cut nitrification-anaerobic ammonia oxidation system at 0.3~0.5 mg / L during the aeration process.

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