Method for synergistically and rapidly propagating anaerobic ammonia oxidation sludge by adding organic carbon source and antibiotics

Abstract

The invention provides a method for synergistically and rapidly expanding cultivation of anaerobic ammonia oxidation sludge by adding an organic carbon source and antibiotics, and belongs to the technical field of sludge expanding cultivation. According to the method, a continuous stirring type reactor is adopted, mature anaerobic ammonia oxidation sludge is taken as an inoculation source, simulated wastewater containing ammonia nitrogen and nitrite nitrogen is taken as inlet water, anhydrous dextrose with COD / TN of 0.4 is added as an organic carbon source, and an antibiotic enrofloxacin is dynamically added in a coordinated manner, so that culture is carried out under an inlet water micro-aerobic condition; the sludge biomass is expanded to be more than five times of the initial biomass, and the high activity is kept. According to the method, the problem of slow growth of anaerobic ammonium oxidation bacteria is relieved, and technical support is provided for process engineering application of the anaerobic ammonium oxidation bacteria.

Description

Technical Field

[0001] The invention relates to the technical field of sludge expansion, and in particular to a method for rapidly expanding anaerobic ammonia oxidation sludge by adding an organic carbon source and an antibiotic. Background Art

[0002] With the increasing demand for wastewater treatment worldwide, efficient and low-energy biological denitrification technology has become a research hotspot. Anaerobic ammonium oxidation technology has been widely regarded as one of the most promising wastewater treatment technologies due to its advantages such as low operating cost and high denitrification efficiency. Anaerobic ammonium oxidation technology can convert electron donor ammonium and electron acceptor nitrite into nitrogen gas under anaerobic or anoxic conditions by anaerobic ammonium oxidizing bacteria, achieving efficient denitrification without the need for an external carbon source. However, the growth rate of anaerobic ammonium oxidizing bacteria is extremely slow and they are highly sensitive to environmental changes. This characteristic limits the widespread application of anaerobic ammonium oxidation processes in actual sewage treatment.

[0003] At present, the expansion method of anaerobic ammonium oxidation sludge usually relies on inorganic carbon source cultivation. Although it can increase the amount of sludge to a certain extent, the expansion cycle is long, the efficiency is low, and the activity is unstable, which makes it difficult to meet the actual engineering needs. In recent years, studies have shown that anaerobic ammonium oxidizing bacteria have a certain potential to metabolize organic carbon sources. The research of our research group found that anaerobic ammonium oxidizing bacteria (such as Candidatus Kuenenia) can metabolize simple organic carbon sources such as glucose for growth. However, the addition of organic carbon sources may lead to excessive proliferation of non-target bacteria (such as denitrifying bacteria), compete with anaerobic ammonium oxidizing bacteria, and even eliminate target bacteria. This makes it difficult to achieve rapid expansion by adding organic carbon sources alone.

[0004] In the existing technology, antibiotics are mostly added to sludge culture systems to inhibit resistant bacteria or competing bacteria in the sludge, selectively enrich specific functional strains, and thus improve the sludge's treatment efficiency for target pollutants. Therefore, this technology mainly focuses on the selective enrichment of specific functional strains, rather than the core measure of maintaining a stable bacterial structure.

[0005] Therefore, there is an urgent need to provide a culture expansion method that can both maintain the relative abundance of anaerobic ammonia-oxidizing bacteria and stabilize the bacterial community structure. Summary of the invention

[0006] In order to solve the above technical problems, the present invention provides a method for rapidly expanding anaerobic ammonium oxidation sludge by adding an organic carbon source and antibiotics. The present invention adds anhydrous glucose as an organic carbon source to promote the rapid growth of biomass in the reactor, and simultaneously adds the antibiotic enrofloxacin as a stabilizer to maintain the relative abundance of anaerobic ammonium oxidizing bacteria in the reactor and achieve the stabilization of the bacterial community structure, thereby successfully expanding the anaerobic ammonium oxidation sludge by more than five times within 40 days and having a higher abundance and activity, providing technical guidance and process parameters for broadening the application of engineered anaerobic ammonium oxidation processes.

[0007] The object of the present invention is to provide a method for rapidly expanding anaerobic ammonium oxidation sludge by adding an organic carbon source and an antibiotic, comprising the following steps:

[0008] Inoculate mature anaerobic ammonium oxidation sludge in the reactor, use glucose as the organic carbon source in combination with antibiotics, and expand the anaerobic ammonium oxidation sludge under micro-aerobic conditions in the influent to achieve the expansion of sludge biomass;

[0009] The antibiotic dosing strategy is to start from the first day with an initial dosing concentration of 0.2 to 1 mg·L -1 , and adjusted according to the biomass growth of the sludge in the reactor, with an increase of 1 to 2 g·L -1 , antibiotic concentration increased by 0.2-1 mg·L -1 ;

[0010] The COD / TN of the influent is 0.4.

[0011] In some embodiments of the present invention, the antibiotic is enrofloxacin;

[0012] The reactor is a continuous stirring reactor to ensure full contact of the culture matrix.

[0013] In some embodiments of the present invention, the dissolved oxygen concentration in the microaerobic condition is 0-0.29 mg·L -1 .

[0014] In some embodiments of the present invention, the total nitrogen in the influent is NH4 + -N and NO2 - -N composition; said NH4 + -N and NO2 - The mass concentration ratio of -N is 1:1 to 1.32, which are 100 to 300 mg·L -1 , total nitrogen is 200~600mg·L -1 ;

[0015] Furthermore, when the COD / TN of the influent is 0.4, the COD concentration is 80-240 mg·L -1 .

[0016] In some embodiments of the present invention, the biomass concentration of the mature anaerobic ammonium oxidation sludge inoculated in the continuous stirred reactor is 1-3 g·L in terms of volatile solid concentration (VSS). -1 .

[0017] In some embodiments of the present invention, the biomass concentration in the continuous stirred tank reactor after inoculation with mature anaerobic ammonium oxidation sludge is 5-8 g·L in terms of volatile solid concentration (VSS). -1 .

[0018] In some embodiments of the present invention, the dominant genus in the anaerobic ammonium oxidizing sludge is Candidatus Kuenenia. In the present invention, adding antibiotics is beneficial to maintaining the relative abundance of anaerobic ammonium oxidizing bacteria in the sludge so that they are not eliminated, thereby maintaining the bacterial community structure; the influent contains nutrients required for the growth of anaerobic ammonium oxidizing bacteria and is suitable for the growth of anaerobic ammonium oxidizing bacteria.

[0019] In some embodiments of the present invention, the pH of the influent is 7.6-7.8, which is most suitable for the growth of anaerobic ammonia-oxidizing bacteria Candidatus Kuenenia, and the hydraulic retention time is 5-8 hours; the temperature of the expansion culture is 16-30°C.

[0020] In some embodiments of the present invention, the mass concentration of glucose is 85.36-256.08 mg·L -1 . Further, containing 120mg·L -1 The amount of COD added is 128.04 mg·L -1 of anhydrous glucose.

[0021] In some embodiments of the present invention, the influent contains NH4Cl, NaNO2, C6H 12 O6, CaCl2·2H2O, MgCl2·6H2O, KHCO3, NaH2PO4, trace element I stock solution and trace element II stock solution,

[0022] The trace element I stock solution is prepared from EDTA·2Na and FeSO4·7H2O;

[0023] The trace element II stock solution contains: MnCl2, ZnSO4·7H2O, CuSO4·5H2O, Na2MoO4·4H2O, H3BO3, CoCl2·6H2O, NiCl2·6H2O and vitamin tablets.

[0024] In some embodiments of the present invention, the operation time of the expansion culture is not less than 40 days.

[0025] The above technical solution of the present invention has the following advantages compared with the prior art:

[0026] The present invention rapidly expands anaerobic ammonium oxidation sludge by adding an organic carbon source and a synergistic effect of antibiotics. The anaerobic ammonium oxidation sludge is successfully expanded more than five times within 40 days and has high activity. Experiments have shown that this method is effective for the expansion of anaerobic ammonium oxidation sludge.

[0027] The beneficial effects of the present invention are mainly reflected in: ① the use of organic carbon source and antibiotics to synergistically expand the anaerobic ammonium oxidation sludge, broadening the application field of the anaerobic ammonium oxidation process; ② the sludge biomass of the anaerobic ammonium oxidation sludge expanded within 40 days is 7.075g·L in terms of volatile solid concentration VSS -1 , which is more than five times the initial biomass, alleviating the problem of slow growth of anaerobic ammonia-oxidizing bacteria. DETAILED DESCRIPTION

[0028] In order to solve the technical problems pointed out in the background technology, the present invention is implemented in the following ways:

[0029] The present invention innovatively introduces the antibiotic enrofloxacin into the anaerobic ammonium oxidation sludge expansion process for the first time, and simultaneously adds the organic carbon source glucose, and effectively maintains the stability of the bacterial community structure of the anaerobic ammonium oxidation sludge during the rapid expansion process through the precise regulation of enrofloxacin. Through the coordinated addition strategy of glucose and enrofloxacin, the present invention achieves the rapid expansion of the amount of anaerobic ammonium oxidation sludge, which not only effectively alleviates the problem of slow sludge growth, but also provides a scientific basis and process guarantee for the promotion of anaerobic ammonium oxidation technology in engineering applications.

[0030] The present invention provides a method for rapidly expanding anaerobic ammonium oxidation sludge by adding an organic carbon source and an antibiotic, comprising the following steps:

[0031] In the reactor, glucose is used as an organic carbon source in combination with antibiotics, and anaerobic ammonium oxidation sludge is cultured under micro-aerobic conditions in the influent to achieve the expansion of sludge biomass.

[0032] The antibiotic dosing strategy is to start from the first day with an initial dosing concentration of 0.2 to 1 mg·L -1 , and adjusted according to the biomass growth of the sludge in the reactor, with an increase of 1 to 2 g·L -1 , antibiotic concentration increased by 0.2-1 mg·L -1 ;

[0033] The COD / TN of the influent is 0.4.

[0034] In a specific embodiment of the present invention, the antibiotic is enrofloxacin; the present invention effectively maintains the stability of the bacterial community structure of anaerobic ammonia oxidation sludge during the rapid expansion process through the precise regulation of enrofloxacin, avoids the excessive proliferation of non-target bacteria (such as denitrifying bacteria), and keeps the relative abundance of anaerobic ammonia oxidation bacteria such as Candidatus Kuenenia stable.

[0035] The reactor is a continuous stirring reactor to ensure full contact of the culture matrix.

[0036] In a specific embodiment of the present invention, the dissolved oxygen concentration in the microaerobic condition is 0-0.29 mg·L -1 , for example, it can be 0, 0.1, 0.11, 0.12, 0.13, 0.14, 0.15, 0.16, 0.17, 0.18, 0.19, 0.20, 0.21, 0.22, 0.23, 0.24, 0.25, 0.26, 0.27, 0.28, 0.29, etc.

[0037] In a specific embodiment of the present invention, the total nitrogen in the influent is NH4 + -N and NO2 - -N composition; said NH4 + -N and NO2 - The mass concentration ratio of -N is 1:1 to 1.32, which are 100 to 300 mg·L -1 , total nitrogen is 200~600mg·L -1 ;

[0038] Furthermore, when the COD / TN of the influent is 0.4, the COD concentration is 80-240 mg·L -1 , for example, it can be 80, 90, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, 200, 210, 220, 230, 240 mg·L -1 wait.

[0039] In a specific embodiment of the present invention, the biomass concentration of the mature anaerobic ammonium oxidation sludge inoculated in the continuous stirred reactor is 1 to 3 g·L in terms of volatile solid concentration (VSS). -1 , for example, it can be 1, 1.5, 2, 2.5, 3 g·L -1 .

[0040] In a specific embodiment of the present invention, the biomass concentration in the continuous stirred reactor after inoculation with mature anaerobic ammonium oxidation sludge is 5-8 g·L in terms of volatile solid concentration (VSS). -1 , for example, it can be 5, 5.5, 6, 6.5, 7, 7.5, 8 g·L-1 wait.

[0041] In a specific embodiment of the present invention, the dominant genus in the anaerobic ammonium oxidizing sludge is Candidatus Kuenenia. In the present invention, adding antibiotics is beneficial to maintaining the relative abundance of anaerobic ammonium oxidizing bacteria in the sludge so that they are not eliminated, thereby maintaining the bacterial community structure; the influent contains nutrients required for the growth of anaerobic ammonium oxidizing bacteria and is suitable for the growth of anaerobic ammonium oxidizing bacteria.

[0042] In a specific embodiment of the present invention, the pH of the influent is 7.6-7.8, which is most suitable for the growth of anaerobic ammonia-oxidizing bacteria Candidatus Kuenenia, and the hydraulic retention time is 5-8 hours; the temperature of the expansion culture is 16-30°C.

[0043] In a specific embodiment of the present invention, the mass concentration of glucose is 85.36-256.08 mg·L -1 , for example, it can be 85.36, 85, 90, 95, 100, 150, 200, 250, 256.08 mg·L -1 wait.

[0044] Furthermore, containing 120 mg·L -1 The amount of COD added is 128.04 mg·L -1 of anhydrous glucose.

[0045] In a specific embodiment of the present invention, the influent contains NH4Cl, NaNO2, C6H 12 O6, CaCl2·2H2O, MgCl2·6H2O, KHCO3, NaH2PO4, trace element I stock solution and trace element II stock solution,

[0046] The trace element I stock solution is prepared from EDTA·2Na and FeSO4·7H2O;

[0047] The trace element II stock solution contains: MnCl2, ZnSO4·7H2O, CuSO4·5H2O, Na2MoO4·4H2O, H3BO3, CoCl2·6H2O, NiCl2·6H2O and vitamin tablets.

[0048] In a specific embodiment of the present invention, the operation time of the expansion culture is not less than 40 days.

[0049] The present invention is further described below in conjunction with specific embodiments so that those skilled in the art can better understand the present invention and implement it, but the embodiments are not intended to limit the present invention.

[0050] Embodiment 1:

[0051] The embodiment of the present invention provides a method for rapidly expanding anaerobic ammonium oxidation sludge by adding an organic carbon source and an antibiotic, and the specific steps are as follows:

[0052] (1) Using a continuous stirred reactor with an effective volume of 1 L, the biomass expressed as volatile solid concentration (VSS) was 2.875 g·L -1 The mature anaerobic ammonium oxidation sludge was used as the inoculation source. After inoculation, the biomass in the reactor expressed by the volatile solid concentration (VSS) was 1.217 g·L -1 , containing 150mg·L -1 Ammonia nitrogen and 150mg·L -1 The simulated wastewater containing nitrite and no deoxygenation treatment was used as the influent. The hydraulic retention time was 6 h. The sludge was cultured at 24 °C and the influent pH was 7.6.

[0053] Among them, the other components of the simulated wastewater used are as follows: ammonia nitrogen 150 mg·L -1 , nitrite nitrogen 150mg·L -1 , KHCO31500mg·L -1 ,MgCl2·6H2O1500mg·L -1 ,CaCl2·2H2O56mg·L -1 , NaH2PO410mg·L -1 , trace element I stock solution and trace element II stock solution, the solvent is water; the amount of the organic carbon source added each time is 128.04 mg·L -1 .

[0054] The composition of trace element I stock solution is:

[0055] (a) EDTA·2Na 5 g·L -1 ,

[0056] (b) FeSO4·7H2O 9.14 g·L -1 .

[0057] The composition of trace element II stock solution is:

[0058]

[0059] (2) Four continuous stirred reactors with an effective volume of 1.0 L were set up. X1 with a COD / TN of 0.4 was used as the experimental group, and X2, X3, and X4 with COD / TN of 0, 0.2, and 0.7 were used as the control group. X1, X3, and X4 were added with 128.04 mg·L -1 , 64.02mg·L -1and 224.07 mg·L -1 Anhydrous glucose. After 40 days of cultivation, the average denitrification efficiency of X1 was 74.85%, while the average denitrification efficiency of X3 and X4 was about 69%, and the average denitrification efficiency of X2 without adding organic carbon source was 65.93%; on the 40th day, a 6-hour in-situ batch experiment was carried out in four reactors to detect anaerobic ammonia oxidation activity. The total nitrogen removal rate of X1 reached the highest 70.46%, the total nitrogen removal rate of X2 was 53.47%, while the total nitrogen removal rate of X3 was only 24.25%, and the total nitrogen removal rate of X4 was 46.73%. Combining the average denitrification efficiency and the results of the in-situ batch experiment, it can be proved that the denitrification effect and sludge activity of the reactor are the highest when COD / TN is 0.4.

[0060] (3) On the 40th day, the sludge biomass of each reactor in (2) was measured. The biomass expressed in terms of volatile solid concentration (VSS) in the X1 reactor with a COD / TN of 0.4 was 6.425 g·L -1 Under the same conditions, the biomass expressed by volatile solid concentration (VSS) in X2, X3 and X4 was 4.426 g·L -1 , 5.478 g·L -1 and 5.971 g·L -1 The biomass in X1 is 31.1%, 14.7% and 7.1% more than that in X2, X3 and X4 respectively. Through COD / TN optimization experiment, it is proved that the sludge biomass expansion efficiency is the highest when COD / TN is 0.4.

[0061] Embodiment 2:

[0062] (1) Based on a COD / TN ratio of 0.4, four continuous stirred reactors with an effective volume of 1.0 L were set up, with a relative abundance of anaerobic ammonia-oxidizing bacteria Candidatus Kuenenia of 16.82% and a biomass expressed as volatile solid concentration (VSS) of 2.875 g·L -1 The mature anaerobic ammonium oxidation sludge was used as the inoculation source. After inoculation, the biomass in the reactor expressed by the volatile solid concentration (VSS) was 1.352 g·L -1 , containing 150mg·L -1 Ammonia nitrogen and 150mg·L -1 The simulated wastewater containing nitrite and not deoxygenated was used as influent, the hydraulic retention time was 6 hours, and the sludge was cultured at 24°C and the influent pH was 7.6. The other components in the simulated wastewater were as described in Example 1.

[0063] (2) Initial enrofloxacin concentration: 0.5 mg·L -1 The biomass in the reactor increases by 2 g·L in terms of volatile solid concentration VSS.-1 , the concentration of enrofloxacin increased by 0.5 mg·L -1 The Z1 group was used as the experimental group, the Z2 group was not added with enrofloxacin, and the enrofloxacin concentration was fixed at 0.5 mg·L -1 and 1mg·L -1 Z3 and Z4 were used as the control group. The four reactors were operated for a total of 40 days. Enrofloxacin was added to Z1, Z3 and Z4 from the first day. The average denitrification efficiency of Z1 was 76.22%, while the average denitrification efficiency of Z3 and Z4 was about 74%. The average denitrification efficiency of Z2 without enrofloxacin was 77.41%. The denitrification performance of the four reactors was roughly the same, which showed that the addition of enrofloxacin did not have a significant effect on the denitrification performance of the anaerobic ammonium oxidation process.

[0064] (3) On the 40th day, the sludge biomass and relative abundance of each reactor in (2) were measured. The biomass expressed in terms of volatile solid concentration (VSS) in the Z1 reactor with dynamic dosing of enrofloxacin was 7.075 g·L -1 Under the same conditions, the biomass expressed by volatile solid concentration (VSS) in Z2, Z3 and Z4 was 4.028 g·L -1 , 6.300 g·L -1 and 5.975 g·L -1 , the biomass in Z1 was 43.1%, 10.9% and 15.5% more than that in Z2, Z3 and Z4, respectively. The relative abundance of the anaerobic ammonia-oxidizing bacteria Candidatus Kuenenia in the Z1 reactor with dynamic dosing of enrofloxacin was 17.85%, and the relative abundance of the anaerobic ammonia-oxidizing bacteria Candidatus Kuenenia in Z2, Z3 and Z4 under the same conditions was 3.36%, 9.54% and 11.93%, respectively, which shows that the dynamic dosing of enrofloxacin can stabilize the relative abundance of the anaerobic ammonia-oxidizing bacteria in the anaerobic ammonia-oxidizing system, avoid its elimination due to the proliferation of competitive bacteria caused by the addition of glucose, thereby maintaining the stability of the bacterial structure and successfully expanding the anaerobic ammonia-oxidizing sludge.

[0065] The present invention uses COD / TN optimization experiments and antibiotic dosing strategy optimization experiments to prove that when COD / TN is 0.4, enrofloxacin has the highest expansion efficiency when it is dynamically added according to biomass. With anhydrous glucose as the organic carbon source and enrofloxacin as the antibiotic, under the condition of COD / TN being 0.4, the dosing strategy is to start from the first day, with an initial dosing concentration of 0.5 mg·L -1 , and adjusted according to the biomass growth of the volatile solids concentration (VSS) of the sludge in the reactor. -1 , the concentration of enrofloxacin increased by 0.5 mg·L -1 The biomass of sludge was increased to 7.075 g·L -1, compared with the initial biomass concentration (1.352 g·L -1 ) increased by more than five times, and the average denitrification efficiency reached 76.22%. The relative abundance of the anaerobic ammonium-oxidizing bacteria CandidatusKuenenia in the sludge was stable at 17.85%, which was basically the same as the initial relative abundance (16.82%). The sludge activity, denitrification efficiency and relative abundance of anaerobic ammonium-oxidizing bacteria in the control group were lower than those in the experimental group, further verifying the effectiveness of COD / TN optimization and antibiotic dosing strategy optimization.

[0066] In this example, by adding glucose with a COD / TN of 0.4 as an organic carbon source and dynamically adding enrofloxacin, the biomass of anaerobic ammonium oxidation sludge was successfully expanded by more than five times within 40 days. At the same time, the relative abundance of anaerobic ammonium oxidizing bacteria in the expanded sludge remained relatively consistent and had good denitrification efficiency. The present invention provides a new perspective and data support for the expansion of anaerobic ammonium oxidation sludge in practical applications, and also provides a new idea and process optimization guidance for the anaerobic ammonium oxidation process to treat wastewater containing organic matter.

[0067] Obviously, the above embodiments are merely examples for clear explanation and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived from these are still within the protection scope of the invention.

Claims

1. A method for rapidly expanding anaerobic ammonium oxidation sludge by adding an organic carbon source and an antibiotic, characterized in that: The following steps are involved: Inoculate mature anaerobic ammonium oxidation sludge in the reactor, use glucose as the organic carbon source in combination with antibiotics, and expand the anaerobic ammonium oxidation sludge under micro-aerobic conditions in the influent to achieve the expansion of sludge biomass; The antibiotic dosing strategy is to start from the first day with an initial dosing concentration of 0.2 to 1 mg·L -1 , and adjusted according to the biomass growth of the sludge in the reactor, with an increase of 1 to 2 g·L -1 , antibiotic concentration increased by 0.2-1 mg·L -1 ; The COD / TN of the influent is 0.

4.

2. The method according to claim 1, characterized in that: The antibiotic is enrofloxacin; The reactor is a continuous stirring reactor to ensure full contact of the culture matrix.

3. The method according to claim 1, characterized in that The dissolved oxygen concentration under the microaerobic condition is 0-0.29 mg·L -1 .

4. The method according to claim 1, characterized in that: The total nitrogen in the influent is NH4 + -N and NO2 - -N composition; said NH4 + -N and NO2 - -N mass concentration ratio is 1:1 to 1.32, the NH4 + -N and NO2 - The mass concentration of -N is 100~300mg·L -1 , total nitrogen is 200~600mg·L -1 .

5. The method according to claim 1, characterized in that The biomass concentration of the mature anaerobic ammonium oxidation sludge inoculated in the reactor is 1-3 g·L in terms of volatile solid concentration (VSS). -1 .

6. The method according to claim 1, characterized in that After inoculation with mature anaerobic ammonium oxidation sludge, the biomass concentration in the reactor is 5-8 g·L in terms of volatile solid concentration (VSS). -1 .

7. The method according to claim 1, characterized in that The dominant bacterial genus in the anaerobic ammonium oxidation sludge is Candidatus Kuenenia.

8. The method according to claim 1, characterized in that The pH of the influent is 7.6-7.8, and the hydraulic retention time is 5-8 hours.

9. The method according to claim 1, characterized in that: The mass concentration of the organic carbon source is 85.36-256.08 mg·L -1 .

10. The method according to claim 1, characterized in that The operation time of the expansion culture is not less than 40 days.

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