A method for rapidly increasing abundance of thauera in mainstream short-cut denitrification sludge
By using a combination of high-concentration volatile acids and oxygen environment control in the short-path denitrification process, the abundance of Thaurea bacteria was rapidly increased, solving the problem of slow Thaurea bacteria enrichment and improving denitrification efficiency and stability.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- HANGZHOU NORMAL UNIVERSITY
- Filing Date
- 2025-08-25
- Publication Date
- 2026-07-07
AI Technical Summary
In short-cut denitrification processes, Thaurera bacteria accumulate slowly and have poor competitiveness, resulting in insufficient nitrogen removal efficiency and stability, especially under low carbon-to-nitrogen ratio conditions where rapid accumulation is difficult.
High-concentration combined volatile acids were used as carbon sources, and carbon source utilization was optimized by alternating between medium-aerobic and high-aerobic aeration, thereby directionally increasing the abundance of Thaurea bacteria.
It increases Thaurera abundance by more than 55% within 1 to 3 cycles, significantly enhances the environmental adaptability and functional stability of the bacterial community, simplifies operation and is highly efficient.
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Figure CN120966695B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of short-cut denitrification technology, specifically to a method for rapidly increasing the concentration of Tauella bacteria (Daucus) in mainstream short-cut denitrification sludge. Thauera Methods for determining bacterial abundance. Background Technology
[0002] Short-cut denitrification has received much attention in the field of wastewater denitrification in recent years because it can efficiently convert nitrates into nitrites, providing a stable substrate for subsequent anaerobic ammonia oxidation.
[0003] For example, the patent specification with publication number CN115745170A discloses a nitrification short-cut denitrification anaerobic ammonium oxidation system and method, the system including an anaerobic zone, a nitrification-short-cut nitrification zone, a short-cut denitrification anaerobic ammonium oxidation zone and an aerobic zone.
[0004] For example, the patent specification with publication number CN116605994A discloses a process for treating ultra-low C / N (2.8±0.5) domestic sewage using a coupled process of anaerobic fermentation, short-cut nitrification, short-cut denitrification and anaerobic ammonia oxidation (IFPNDA) based on an anaerobic baffled reactor (ABR) combined with a continuous flow completely mixed reactor (CSTR). The study found that in the IFPNDA process, Tauella and Nitrosomonas in different compartments are the main functional bacteria for NO2N supply.
[0005] However, short-cut denitrification processes face challenges in practical applications due to the presence of core functional microbial communities (such as...). Thauera Key bottlenecks such as slow bacterial enrichment rate and poor competitiveness severely restrict the process start-up efficiency and operational stability.
[0006] The low carbon-to-nitrogen ratio and the use of a single carbon source, which are common in mainstream wastewater treatment plants, have exacerbated the problem. Thauera The difficulty in enriching bacteria results in low abundance and weak competition, which severely restricts the nitrogen removal efficiency and stability of the short-cut denitrification process.
[0007] Therefore, it is necessary to develop a method that can rapidly and efficiently enrich... Thauera The technology of using bacteria can not only significantly improve the nitrite accumulation rate and provide a stable substrate for anaerobic ammonia oxidation, but also optimize the carbon source utilization efficiency, achieving the dual goals of resource recovery and energy conservation in the wastewater treatment process. Summary of the Invention
[0008] To address the aforementioned technical problems and shortcomings in the field, this invention provides a method for rapidly improving the efficiency of mainstream short-cut denitrification sludge. Thauera Methods for measuring bacterial abundance.
[0009] This invention achieves targeted regulation of the oxygen environment (medium oxygen storage - high oxygen starvation alternation) by optimizing the combination and dosage of carbon sources and dynamically controlling the oxygen environment. Thauera The bacteria gain a significant advantage in nutrient competition, and this culture mode only requires 1-3 cycles to achieve this. Thauera It increases bacterial abundance by 55% or even more than 70%, and significantly enhances the environmental adaptability and functional stability of the bacterial community. It is characterized by simple operation, high efficiency and strong stability.
[0010] The specific technical solution is as follows:
[0011] A method for rapidly increasing the abundance of Tauella bacteria in mainstream short-cut denitrification sludge includes the following steps:
[0012] (1) Sludge inoculation: Inoculate mainstream short-cut denitrification sludge in an open container;
[0013] (2) Add a selective culture medium with high concentration of combined volatile acids as the dominant carbon source and a significantly limited nitrogen-phosphorus ratio;
[0014] The combined volatile acids include any two or more of acetic acid, propionic acid, butyric acid, and valeric acid.
[0015] The cumulative content of acetic acid, propionic acid, and butyric acid in the combined volatile acids accounts for 50% to 80% of the total carbon source by mass.
[0016] The nitrogen-phosphorus ratio is significantly limited, meaning that the COD / NH4 ratio in the selective culture medium is... + -N range 50~250:1, COD / PO4 3- -P ranges from 100 to 300:1 (e.g., 200:1, etc.);
[0017] (3) Medium-oxygen aeration: This promotes the efficient conversion of externally added volatile acids into internal carbon sources by the Tauella bacteria, which have excellent storage capacity; the initial dissolved oxygen (DO) of medium-oxygen aeration is 2.0~3.0 mg L. -1 And maintain this aeration rate;
[0018] (4) Sedimentation and drainage: When dissolved oxygen rises to >6.0 mg / L -1 Aeration was then stopped and the nutrient solution was removed by sedimentation.
[0019] (5) Hyperaeration: Maintaining hyperaeration forces the microbial community to rely on its endogenous reserves for aerobic metabolism; by controlling the duration of hyperaeration, it ensures that Taureella can maximize the use of its stored carbon sources for respiration and proliferation, while other competing bacterial groups gradually die out because they cannot provide high maintenance energy for a long time; the hyperaeration control condition is dissolved oxygen > 6.0 mg / L -1 For example, >6.2 mg / L -1 >6.3 mg / L -1>6.4 mg / L -1 Etc., preferably >6.4 mg / L -1 ;
[0020] (6) Allow the supernatant to stand and separate to obtain mainstream short-cut denitrification sludge enriched with Tauerella bacteria; or, repeat steps (2) to (5) 1 to 3 times (e.g., 2 times), and then allow the supernatant to stand and separate to obtain mainstream short-cut denitrification sludge enriched with Tauerella bacteria.
[0021] Preferably, in step (2), after adding the selective culture medium, the sludge concentration is 1.0~1.5 gVSS L. -1 .
[0022] In some preferred embodiments, the combined volatile acids include acetic acid, propionic acid, and butyric acid. More preferably, the mass ratio of acetic acid, propionic acid, and butyric acid in the combined volatile acids is 1~3:1~3:1~3.
[0023] In some preferred embodiments, the carbon source in the selective culture medium also includes valeric acid.
[0024] In some preferred embodiments, in step (2), the total organic carbon concentration in the selective culture medium is 2.5~5.0 gCODL. -1 For example, 3 g COD L -1 wait.
[0025] In some preferred embodiments, in step (2), the nitrogen source in the selective culture medium includes ammonium sulfate.
[0026] In some preferred embodiments, in step (2), the phosphorus source in the selective culture medium includes disodium hydrogen phosphate.
[0027] Step (3) is the exogenous storage metabolic process. In step (3), the initial aeration rate is set to achieve an initial dissolved oxygen level of 2.0~3.0 mg / L. -1 The design maintains a constant aeration rate throughout the subsequent culture process, while exogenous storage and metabolism gradually increase dissolved oxygen. Dissolved oxygen reaches its scalation point (4.0–6.0 mg / L). -1 When the exogenous storage cycle stops (i.e., step (4), the nutrient solution is removed, and then step (5) is performed. Step (5) is the endogenous growth and metabolism process.
[0028] In some embodiments, the oxygen aeration time in step (3) is 1 to 3 hours, such as 2 hours.
[0029] Preferably, in step (4), the sedimentation method for removing the nutrient solution refers to separating 1 / 2 to 2 / 3 of the supernatant after standing.
[0030] In some preferred embodiments, the duration of hyperaeration in step (5) is 1 to 3 times, for example, 2 times, the duration of oxygen aeration in step (3).
[0031] In some preferred embodiments, in step (6), the amount of selective culture medium added when repeating step (2) is 1 / 2 to 2 / 3 of the initial amount of selective culture medium added.
[0032] In some preferred embodiments, in step (6), the amount of selective culture medium added when repeating step (2) is the same as the amount of nutrient medium removed by sedimentation in the previous step (4).
[0033] In some preferred embodiments, the method for rapidly increasing the abundance of Tauella in mainstream short-cut denitrification sludge is performed 1 to 3 times (e.g., 2 times) of steps (2) to (5).
[0034] In some embodiments, the method for rapidly increasing the abundance of Tauella bacteria in mainstream short-cut denitrification sludge further includes the following steps:
[0035] (7) The mainstream short-cut denitrification sludge enriched with Tauerella bacteria obtained in step (6) is returned to the mainstream short-cut denitrification reactor.
[0036] Preferably, the pH of each step in the method for rapidly increasing the abundance of Tauella in mainstream short-cut denitrification sludge is controlled at 7.5 to 8.5, for example, 7.6, 8.0, 8.4, etc.
[0037] Preferably, the temperature of each step in the method for rapidly increasing the abundance of Tauella in mainstream short-cut denitrification sludge is controlled at 20~30℃, for example, 25℃.
[0038] The method described for rapidly increasing the abundance of Tauella in mainstream short-path denitrification sludge specifically refers to Tauella species enriched with... Thaueraaminoaromatica , Thaueraphenylacetica , Thaueraterpenica , Thauera sp. DNT-1 , Thauera sp. MZ1T Short-range denitrifying bacteria are represented by these.
[0039] Compared with the prior art, the beneficial effects of this invention are as follows:
[0040] This invention employs a specific high-concentration combination of volatile acids and low-nitrogen and phosphorus nutrient solution, combined with a controllable medium-oxygen aeration exogenous storage-high-oxygen aeration endogenous growth cycle strategy, to drive a rapid increase in the abundance of Tauella bacteria in the sludge community.
[0041] For mainstream short-cut denitrification sludge with Taunerella abundance below 30% or even 10%, the method of this invention can increase the Taunerella abundance in the sludge by 55% or even more than 70% in just 1 to 3 cycles. The final sludge has a Taunerella abundance of more than 80% or even more than 90%, and significantly enhances the environmental adaptability and functional stability of the microbial community. It is characterized by simple operation, high efficiency and strong stability. Attached Figure Description
[0042] Figure 1 The diagram shows the microbial community structure of sludge inoculum S_A_100 and the acetic acid-based experimental group S_A_50 from Example 1.
[0043] Figure 2 The diagram shows the microbial community structure of sludge inoculum S_A_100 and propionic acid type experimental group S_P_50 in Example 2.
[0044] Figure 3 The diagram shows the microbial community structure of sludge inoculum S_A_100 and butyric acid type experimental group S_B_50 in Example 3.
[0045] Figure 4 The diagram shows the microbial community structure of sludge inoculum S_A_100 and valeric acid type experimental group S_V_50 in Example 4. Detailed Implementation
[0046] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention.
[0047] Unless otherwise specified, the operating methods in the following examples are generally performed under conventional conditions or as recommended by the manufacturer.
[0048] Example 1:
[0049] A method to rapidly improve the performance of mainstream short-cut denitrification sludge Thauera Methods for bacterial abundance include:
[0050] Take the mainstream short-cut denitrification sludge S_A_100 from the mainstream short-cut denitrification reactor and place it in an open container. The sludge concentration is controlled at 1.0 gVSS L. -1 An acetic acid-based culture medium containing a high concentration of combined volatile acids and low nitrogen and phosphorus was added. The carbon source composition was acetic acid:propionic acid:butyric acid:valeric acid in a mass ratio of 3:1:1:1. The total organic carbon concentration in the culture medium was 3.0 g COD / L. -1 The ammonium sulfate concentration was 12.0 mgN / L. -1 Disodium hydrogen phosphate is 15.0 mg / L. -1 .
[0051] Aerobic aeration was used for aerobic exogenous storage, with an initial DO concentration of 3.0 mg / L. -1 The aeration rate was kept constant, the pH was controlled at 7.5-8.5, the temperature was 25℃, and the time was 1 hour, until the dissolved oxygen reached its peak.
[0052] After the oxygenation process ends, sedimentation and drainage are carried out. Aeration is stopped, and the nutrient solution is removed by sedimentation, that is, after standing, half of the supernatant is separated.
[0053] Hyperoxic aeration was used to prolong aerobic starvation, with DO > 6.4 mg / L. -1 The duration was 2 hours, the pH was controlled at 7.5~8.5, and the temperature was 25℃.
[0054] Two cycles were performed, consisting of one cycle of adding culture medium, medium-oxygen aeration, settling and draining, and then high-oxygen aeration. The amount of culture medium added during each cycle was the same as the amount of supernatant separated in the previous settling and draining process. Finally, the supernatant was allowed to stand and separate to obtain sludge enriched with microorganisms. Sequencing results are shown below. Figure 1 As shown, from Figure 1 It can be seen that compared with inoculum S_A_100, the acetic acid-based experimental group sludge S_A_50... Thauera The abundance was increased by about 70% within a few hours.
[0055] Example 2:
[0056] A method for rapidly increasing the abundance of *Daucus* spp. in mainstream short-cut denitrification sludge includes:
[0057] The mainstream short-cut denitrification sludge S_A_100 from the mainstream short-cut denitrification reactor was inoculated into an open culture system, with the sludge concentration controlled at 1.0 g VSS L. -1 A specific ratio of volatile acid mixture was added to the culture medium, with the carbon source composition being acetic acid:propionic acid:butyric acid:valeric acid in a mass ratio of 1:3:1:1. The total COD of the culture medium was 3.0 g COD / L. -1 Simultaneously control nitrogen and phosphorus nutrient levels, ammonium sulfate 12.0 mgN L -1 Disodium hydrogen phosphate 15.0 mg / L -1 .
[0058] Under conditions of 25℃ and pH=7.6~8.0, the aerobic exogenous carbon storage stage was first implemented with medium-aerobic aeration, with an initial DO=3.0 mg L / L. -1 The aeration rate was kept constant for 1 hour until the dissolved oxygen reached its peak.
[0059] After the oxygenation process ends, sedimentation and drainage are carried out. Aeration is stopped, and the nutrient solution is removed by sedimentation, that is, after standing, half of the supernatant is separated.
[0060] Subsequently, under conditions of 25℃ and pH=7.6~8.0, hyperaerobic aeration was performed to transition to an extended aerobic starvation phase, with DO>6.3mg / L. -1 The duration is 2 hours.
[0061] A cycle was performed consisting of one addition of culture medium, medium-oxygen aeration, sedimentation and drainage, and high-oxygen aeration, for a total of three cycles. The amount of culture medium added during each cycle was the same as the amount of supernatant separated in the previous sedimentation and drainage process. Finally, the supernatant was separated by settling to obtain sludge enriched with microbial communities. Sequencing results are as follows: Figure 2 As shown, from Figure 2 It can be seen that compared with the inoculum S_A_100, the propionic acid type experimental group sludge S_P_50 contains Thauera The abundance of bacteria was increased by about 65% within a few hours.
[0062] Example 3:
[0063] A method for rapidly increasing the abundance of *Daucus* spp. in mainstream short-cut denitrification sludge includes:
[0064] Take the mainstream short-cut denitrification sludge S_A_100 from the mainstream short-cut denitrification reactor and place it in an open container. The sludge concentration is controlled at 1.0 gVSS L. -1 A volatile acid culture medium with butyric acid as the dominant carbon source was added, wherein the carbon source composition was acetic acid:propionic acid:butyric acid:valeric acid in a mass ratio of 1:1:3:1. The total COD of the culture medium was 3.0 g COD / L. -1 Add 12.0 mg N L of ammonium sulfate. -1 Disodium hydrogen phosphate 15.0 mg / L -1 Maintain low nitrogen and phosphorus nutrition conditions.
[0065] At a constant temperature of 25℃ and a pH range of 7.6–8.4, the aerobic exogenous storage phase was initiated with initial aeration using moderate oxygenation, with a DO concentration of 3.0 mg / L. -1 The aeration rate was kept constant for 1 hour until the dissolved oxygen reached its peak.
[0066] After the oxygenation process ends, sedimentation and drainage are carried out. Aeration is stopped, and the nutrient solution is removed by sedimentation, that is, after standing, half of the supernatant is separated.
[0067] Subsequently, the system was kept at a constant temperature of 25℃ and a pH range of 7.6–8.4, and then transitioned to an aerobic, prolonged starvation phase with DO > 6.2 mg / L. -1 The duration is 2 hours.
[0068] Finally, the supernatant was allowed to stand and separate to obtain sludge enriched with microorganisms. The sequencing results are as follows: Figure 3 As shown, from Figure 3It can be seen that compared with inoculum S_A_100, the butyric acid type experimental group sludge S_B_50 contains Thauera The abundance of bacteria was increased dramatically by about 62% within a few hours.
[0069] Example 4:
[0070] A method for rapidly increasing the abundance of *Daucus* spp. in mainstream short-cut denitrification sludge includes:
[0071] Take the mainstream short-cut denitrification sludge S_A_100 from the mainstream short-cut denitrification reactor and place it in an open container. The sludge concentration is controlled at 1.0 gVSS L. -1 A volatile acid culture medium with valeric acid as the dominant carbon source was added, wherein the carbon source composition was acetic acid:propionic acid:butyric acid:valeric acid in a mass ratio of 1:1:1:3. The total COD of the culture medium was 3.0 g COD / L. -1 Add 12.0 mg N L of ammonium sulfate. -1 Disodium hydrogen phosphate 15 mg / L -1 Maintain low nitrogen and phosphorus nutrient conditions.
[0072] Under constant temperature conditions of 25℃, and by precisely controlling the pH within the range of 7.5 to 8.0, a medium-aerobic aeration was first implemented for the aerobic exogenous storage phase, with an initial DO of 3.0 mg / L. -1 The aeration rate was kept constant for 1 hour until the dissolved oxygen reached its peak.
[0073] After the oxygenation process ends, sedimentation and drainage are carried out. Aeration is stopped, and the nutrient solution is removed by sedimentation, that is, after standing, half of the supernatant is separated.
[0074] Subsequently, under constant temperature conditions of 25℃, and by precisely controlling the pH within the range of 7.5~8.0, high-oxygen aeration was carried out to enter the extended aerobic starvation phase, with DO > 6.0 mg / L. -1 The time is 2 hours.
[0075] Two cycles were performed, consisting of one cycle of adding culture medium, medium-oxygen aeration, settling and draining, and then high-oxygen aeration. The amount of culture medium added during each cycle was the same as the amount of supernatant separated in the previous settling and draining process. Finally, the supernatant was allowed to stand and separate to obtain sludge enriched with microorganisms. Sequencing results are shown below. Figure 4 As shown, from Figure 4 It can be seen that compared with the inoculum S_A_100, the valeric acid type experimental group sludge S_V_50 contains Thauera The abundance was increased by about 59% within a few hours.
[0076] Furthermore, it should be understood that after reading the above description of the present invention, those skilled in the art can make various alterations or modifications to the present invention, and these equivalent forms also fall within the scope defined by the appended claims.
Claims
1. A method for rapidly increasing the abundance of *Daucus* in mainstream short-cut denitrification sludge, characterized in that, Including the following steps: (1) Sludge inoculation: Inoculate mainstream short-cut denitrification sludge in an open container; (2) Add a selective culture medium with high concentration of combined volatile acids as the dominant carbon source and a significantly limited nitrogen-phosphorus ratio; The combined volatile acids consist of acetic acid, propionic acid, butyric acid, and valeric acid; The cumulative content of acetic acid, propionic acid, and butyric acid in the combined volatile acids accounts for 50% to 80% of the total carbon source by mass. Significantly limited nitrogen to phosphorus ratio means that the COD / NH4 + - N range 50-250: 1, COD / PO4 3- - P range 100-300: 1; (3) Medium-oxygen aeration: This promotes the efficient conversion of exogenous volatile acids into internal carbon sources by the Taurella bacteria, which have excellent storage capacity; the initial dissolved oxygen level during medium-oxygen aeration is 2.0~3.0 mg / L. -1 And maintain this aeration rate; (4) Sedimentation and drainage: When dissolved oxygen reaches the jump point of 4.0~6.0 mg / L -1 Aeration was then stopped and the nutrient solution was removed by sedimentation. (5) Hyperoxic aeration: Maintaining hyperoxic conditions forces the microbial community to rely on its endogenous reserves for aerobic metabolism; by controlling the duration of hyperoxic aeration, it ensures that Taureella can maximize the use of its stored carbon sources for respiration and proliferation, while other competing bacterial groups gradually die out because they cannot provide high maintenance energy for a long time; the hyperoxic aeration control condition is dissolved oxygen > 6.0 mg L -1 ; (6) The supernatant was separated by standing to obtain mainstream short-cut denitrification sludge enriched with Dauerella bacteria; Alternatively, repeat steps (2) to (5) 1 to 3 times, and then let the supernatant stand to separate, to obtain mainstream short-cut denitrification sludge enriched with Tauella bacteria.
2. The method according to claim 1, characterized in that, In step (2), after adding the selective culture medium, the sludge concentration is 1.0~1.5 gVSS L. -1 .
3. The method according to claim 1, characterized in that, In step (2), the total organic carbon concentration in the selective culture medium is 2.5~5.0 g COD L. -1 .
4. The method according to claim 1, characterized in that, In step (4), sedimentation to remove nutrient solution means separating 1 / 2 to 2 / 3 of the supernatant after standing.
5. The method according to claim 1, characterized in that, The duration of hyperaeration in step (5) is 1 to 3 times the duration of aeration in step (3).
6. The method according to claim 1, characterized in that, In step (6), the amount of selective culture medium added when repeating step (2) is the same as the amount of nutrient medium removed by sedimentation in the previous step (4).
7. The method according to claim 1, characterized in that, The method further includes the following steps: (7) The mainstream short-cut denitrification sludge enriched with Tauerella obtained in step (6) is returned to the mainstream short-cut denitrification reactor.
8. The method according to claim 1, characterized in that, The pH of each step in the reaction process of the method is controlled at 7.5~8.5, and the temperature is controlled at 20~30℃.