Method for realizing rapid enrichment of anaerobic ammonium oxidation bacteria through NLR and HRT combined regulation and control

Abstract

The invention relates to a method for enriching anaerobic ammonium oxidation bacteria under combined regulation and control of NLR and HRT in the technical field of biological sewage treatment, and aims to solve the problems that the anaerobic ammonium oxidation bacteria are greatly influenced by the environment and are slowly enriched, NH4 < + >-N and NO2 <->-N with low matrix concentration are pumped into an SBR (Sequencing Batch Reactor); and the enrichment of anaerobic ammonium oxidation bacteria is successfully realized by continuously changing hydraulic retention time and water inlet matrix concentration. The total nitrogen removal rate is stabilized at 75%, the removal efficiency is good, the reactor can be flexibly regulated and controlled, rapid starting of the anaerobic ammonia oxidation reactor is facilitated, and a theoretical reference is provided for practical application of the Anammox process. The system is simple to operate, convenient to operate and manage and high in treatment efficiency, and has a good popularization and application prospect.

Description

Technical Field

[0001] The present invention belongs to the technical field of biological sewage treatment, and specifically relates to a device and method for realizing rapid enrichment of anaerobic ammonia-oxidizing bacteria through joint regulation of load and hydraulic retention time. Background Art

[0002] Excessive discharge of nitrogen and phosphorus into water bodies can lead to eutrophication, which is one of the most pressing environmental issues in the world. In order to protect water resources, especially in areas with water shortages, it is very important to remove nitrogen from wastewater, so many countries have implemented strict nitrogen emission standards in recent years. Normally, wastewater denitrification is first carried out through nitrification and then denitrification. Both processes usually consume energy and require a large amount of external carbon source, which increases operating costs. Compared with traditional nitrification and denitrification technology, anaerobic ammonium oxidation has the advantages of low oxygen demand, low operating costs and no need for any external carbon source.

[0003] Anaerobic ammonium oxidation (ANAMMOX) is an autotrophic denitrification process that uses ammonia nitrogen (NH 4 + -N) as electron donor, with nitrite (NO 2 - -N) is an electron acceptor biological reaction, and the reaction product is nitrogen. Due to its advantages of low oxygen demand, no need for external carbon source, low sludge production and no secondary pollution, it has broad application prospects in the field of sewage denitrification. Anaerobic ammonium oxidizing bacteria have a low growth rate, a long doubling time, and are easily affected by temperature, pH, and influent substrate concentration. Therefore, it is very necessary to explore and optimize the start-up conditions of the anaerobic ammonium oxidation reactor.

[0004] The shortcomings of the existing technology are that the existing anaerobic ammonia-oxidizing bacteria are difficult to enrich and are greatly affected by the environment, which limits their application to a certain extent. Summary of the invention

[0005] The purpose of the present invention is to provide a method for rapid enrichment of anaerobic ammonia oxidizing bacteria by jointly regulating NLR and HRT, so as to solve the problems in the prior art that anaerobic ammonia oxidizing bacteria are difficult to enrich and are greatly affected by the environment. The enrichment of anaerobic ammonia oxidizing bacteria is achieved by jointly regulating load and hydraulic retention time.

[0006] To this end, one of the purposes of the present invention is achieved in this way: a method for rapidly enriching anaerobic ammonia-oxidizing bacteria by combined regulation of NLR and HRT, comprising the following steps:

[0007] (1) Selection of inoculated sludge and reactor and setting of experimental parameters: The SBR reactor was inoculated with anaerobic ammonium-oxidizing flocculent sludge, the reactor inlet water was artificial simulated wastewater, the water temperature in the reactor was stabilized at 29-35°C, the pH was controlled between 7.4-8.4, and the dissolved oxygen concentration was controlled between 0-0.4 mg / L; the outside of the reactor was shielded with a shade cloth to protect the reactor from light;

[0008] (2) The simulated wastewater was treated in several cycles using an SBR reactor, and each treatment cycle included: water inlet, reaction, precipitation, water outlet and idle, which were cyclically performed; the SBR reactor was operated in five stages in total, and stage I was an activity recovery period. When the ammonia nitrogen and nitrite removal rates reached 80%, the influent substrate concentration and hydraulic retention time were adjusted to proceed to stage II. When the ammonia nitrogen and nitrite removal rates reached a stable value, the hydraulic retention time was adjusted to increase the nitrogen load to proceed to stage III. After the ammonia nitrogen and nitrite removal rates reached a stable value, the influent substrate concentration was increased to increase the nitrogen load to proceed to stage IV. When the ammonia nitrogen and nitrite removal rates reached a stable value, the hydraulic retention time was further reduced to increase the nitrogen load to proceed to stage V. When the ammonia nitrogen and nitrite removal rates reached a stable value, the reactor was operated until the ammonia nitrogen and nitrite removal rates of the reactor were greater than 80% and the total nitrogen removal rate reached more than 75%;

[0009] (3) Convert simulated wastewater into actual wastewater that needs to be treated and operate it stably for a long time.

[0010] Furthermore, in step (2), the SBR reactor is operated for 2 cycles per day. In each cycle, water is introduced for 15-25 minutes, the stirring reaction time is 4.5-8 hours, the static sedimentation time is 45-75 minutes, the drainage time is 15-25 minutes, and the rest is idle time. The drainage ratio is 40-60%, and sludge is not actively discharged during the operation of the reactor.

[0011] Furthermore, the MLSS of the inoculated anaerobic ammonium-oxidizing flocculent sludge was 3300 mg / L, and the inoculation amount accounted for one fifth of the volume of the SBR reactor.

[0012] Furthermore, the simulated wastewater influent matrix is ​​composed of NH 4 Cl and NaNO 2 Provided, the components of simulated wastewater are: NH 4 + -N, 30-40mg / L; NO 2 - -N, 30-40mg / L; KH 2 PO 4 , 20mg / L; NaHCO 3 , 500mg / L.

[0013] Furthermore, trace elements I and II are added to the simulated wastewater daily, and the components of trace element I are Na 2 -EDTA·2H 2 O, 5000mg / L; FeSO 4 7H 2 O, 5000 mg / L; the component of trace element II is Na 2 -EDTA·2H 2 O, 15000mg / L; ZnSO 4 7H 2 O, 420 mg / L; CoCl 2 6H 2 O, 240 mg / L; MnCl 2 ·4H 2 O, 1000mg / L; CuSO 4 ·5H 2 O, 250 mg / L; NaMoO 4 ·2H 2 O, 250mg / L; NiCl 2 6H 2 O, 200 mg / L; Na 2 SeO 4 , 250mg / L; H 3 BO 3 , 15mg / L; the daily addition amount of trace elements I and II is 1 / 5000-1 / 20000 of the total weight of the water on that day.

[0014] Specifically, the reactor in step (2) runs for a total of 300 cycles, and the corresponding five stages are:

[0015] Phase I: Run 1-60 cycles, NH 4 + -N inlet concentration is 30mg / L, NO 2 - -N influent concentration is 40mg / L, hydraulic retention time in this stage is 8h (average nitrogen load is 0.24kgN / (m 3 d));

[0016] Phase II: Run 61-120 cycles; NH 4 + -N, NO 2 - -N influent concentration is 30mg / L, hydraulic retention time is 6h (average nitrogen load is 0.28kgN / (m 3 d));

[0017] Phase III: Run 121-180 cycles; NH4 + -N, NO 2 - -N influent concentration was kept constant at 30 mg / L, and the hydraulic retention time was adjusted to 5 h (average nitrogen load was 0.32 kgN / (m 3 d));

[0018] Phase IV: Run 181-240 cycles; adjust NH 4 + -N, NO 2 - -N influent concentration was 40 mg / L, hydraulic retention time was kept constant at 5 h (average nitrogen load was 0.41 kgN / (m 3 d));

[0019] Phase V: 241-300 cycles of operation; the influent ammonia nitrogen concentration remained unchanged, and the hydraulic retention time was adjusted to 4.5h (the average nitrogen load was 0.46kgN / (m 3 ·d)).

[0020] Compared with the prior art, the present invention has the following advantages:

[0021] (1) Using low substrate concentration influent can effectively avoid the inhibition of FA and FNA on anaerobic ammonia-oxidizing bacteria.

[0022] (2) The combined regulation strategy of gradually increasing NLR and reducing HRT was adopted to accelerate the domestication and enrichment of anaerobic ammonia-oxidizing bacteria.

[0023] (3) The online control system can monitor the changes in DO and pH in the reactor in real time. At the same time, the heating rod can control the water temperature within a suitable range, creating good conditions for the growth of anaerobic ammonia-oxidizing bacteria.

[0024] The method of the present invention is a method of achieving rapid enrichment of anaerobic ammonium oxidizing bacteria through the combined regulation of NLR and HRT, which is conducive to the rapid start-up of the anaerobic ammonium oxidation reactor and provides a theoretical reference for the practical application of the Anammox process. In addition, it is simple to operate, convenient to operate and manage, has high processing efficiency, and has a good prospect for promotion and application. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a schematic diagram of the structure of the device for achieving the enrichment of anaerobic ammonia-oxidizing bacteria of the present invention.

[0026] Figure 2 Figure 2 is a pie chart of the bacterial community structure, where (a) is the bacterial community structure at the beginning of the experiment, and (b) is the bacterial community structure at the end of the experiment.

[0027] In the figure, 1. water inlet pump; 2. heating rod; 3. sampling port; 4. water outlet; 5. electric stirrer; 6. pH and dissolved oxygen meter; 7. water inlet tank; 8. water outlet tank; 9. PLC control box. DETAILED DESCRIPTION

[0028] like Figure 1 As shown, it is a device for enriching anaerobic ammonia-oxidizing bacteria, wherein the water inlet pump 1 is used to pump water in the water inlet tank 7 into the SBR reactor; the heating rod 2 in the SBR reactor is used to adjust the water temperature; the SBR reactor is provided with a water outlet 4 connected to the water outlet tank 8, and the SBR reactor is also provided with an electric stirrer 5, which can accelerate the reaction by stirring. The sampling port 3 is used for sampling and testing, the pH and dissolved oxygen meter 6 is used for online monitoring of the pH value and dissolved oxygen in the water, and the PLC control box 9 is used for overall control.

[0029] The method for enriching anaerobic ammonia-oxidizing bacteria in the SBR reactor modified by the above device has the following specific steps:

[0030] (1) Inoculation of SBR reactor with sludge

[0031] The test uses an SBR reactor, whose main body is a cylindrical organic glass container with an effective volume of 5L, a height of 300mm, and a cylindrical diameter of 200mm. A row of sampling ports with a spacing of 100mm are set in the vertical direction on the reactor wall for sampling and drainage. The reactor is supplemented with a time-controlled switch, a constant temperature heating rod, a solenoid valve, a water inlet pump, an electric stirrer, a pH, DO meter and other devices. The reactor is inlet to the upper part and outlet to the middle part. Anaerobic ammonia oxidizing bacteria are commercially available, manufacturer: Shandong Luxing Environmental Protection Technology Co., Ltd.; model: LXHJ65; effective ingredient content 90%, pH value 6.5; brand: Luxing; the anaerobic ammonia oxidizing bacteria are inoculated into a sludge treatment tank of a sewage treatment plant, and the test inoculated sludge of the present invention is taken from the sludge treatment tank, MLSS is 3300mg / L, the inoculation amount is one-fifth of the reactor volume, and the inoculated sludge contains a small amount of anaerobic ammonia oxidizing bacteria. The inoculated sludge can also be directly prepared with commercially available anaerobic ammonia oxidizing bacteria.

[0032] (2) Composition and concentration of culture medium

[0033] The test water used was artificial simulated wastewater, and the influent matrix was NH 4 Cl and NaNO 2 The concentrations of the two were adjusted according to the operating results, and no organic carbon source was added to the reactor during the entire test. The composition of the simulated wastewater is shown in Table 1.

[0034] Table 1 Simulated sewage quality

[0035] Water distribution index Concentration (mg / L) <![CDATA[NH 4 + -N]]> 30-40 <![CDATA[NO 2 - -N]]> 30-40 <![CDATA[KH 2 AFTER 4 ]]> 20 <![CDATA[MgSO 4 ·7H 2 Oh]]> 350 <![CDATA[CaCl 2 ·2H 2 Or]]> 30 <![CDATA[NaHCO 3 ]]> 500

[0036] Table 2 is a trace element table. Trace elements I and II are added once a day. The daily addition amount is 1 / 5000-1 / 20000 of the total weight of the water body on that day. The components and concentrations of trace elements I and II are as follows:

[0037] Table 2 Trace elements

[0038]

[0039]

[0040] (3) Operation parameters

[0041] The test was operated in an intermittent water inlet and outlet mode. The water temperature in the reactor was stabilized at 29-35°C, the pH was controlled between 7.4-8.4, and the dissolved oxygen concentration was controlled at 0-0.4 mg / L. The reactor was shielded with a shading cloth to strictly protect the reactor from light. The reactor was operated for two cycles a day, and the operating time within the cycle was changed according to the hydraulic retention time. In each cycle, the water was inlet for 15-25 minutes, the stirring reaction time was 4.5-8 hours, the static sedimentation was 60 minutes, the drainage was 15-25 minutes, and the rest was idle time. The drainage ratio was set to one-half. The reactor did not actively discharge mud during operation.

[0042] (4) Operation results

[0043] ① Phase I (1-60 cycles), NH 4 + -N and NO 2 - -N influent concentrations were 30mg / L and 40mg / L, respectively, and the average nitrogen load was 0.24kgN / (m 3 ·d), the hydraulic retention time is 8h. The effluent concentration fluctuates greatly during this stage. This may be due to the fact that the anaerobic ammonia-oxidizing bacteria are gradually adapting to the new environment. In the first 20 cycles, NH 4 + -N and NO 2 - -N removal rate dropped sharply to the lowest of 48.68% and 38.68% respectively, and the total nitrogen removal rate was 38.05%. After 20 cycles, NH 4 + -N and NO 2 - -N effluent concentration gradually decreased, and the removal rate gradually increased. 4 + -N and NO 2 - -N removal rates were stable at around 80% and 70%, respectively, total nitrogen removal rate was stable at 65%, and NO 3 -The -N concentration increased slightly, which may be due to the presence of some denitrifying bacteria in the reactor.

[0044] ② Phase II (61-120 cycles), average nitrogen load is 0.28kgN / (m 3 ·d) Due to the phase I NH 4 + -N is almost completely degraded, NO 2 - -N still has about 10mg / L, so in Phase II, NH 4 + -N and NO 2 - The inlet and outlet concentrations of -N were both 30 mg / L, the hydraulic retention time was 6 h, and the NH 4 + -N and NO 2 - -N effluent concentration is relatively stable, with removal rates of about 95% and 98% respectively, and total nitrogen removal rate of 80%. 3 - When -N concentration increases by 5-6 mg / L, the activity of anaerobic ammonia-oxidizing bacteria is enhanced.

[0045] ③ Stage III (121-180 cycles), during this stage NH 4 + -N and NO 2 - -N influent concentration is still 30mg / L, and the average nitrogen load is 0.32kgN / (m 3 ·d), the hydraulic retention time is reduced to 5h. Due to the reduction of hydraulic retention time, NH 4 + -N and NO 2 - -N effluent concentration fluctuated greatly, but the total nitrogen removal rate was still around 70%. After 10 cycles, NH 4 + -N and NO 2 - -N effluent concentration is relatively stable, NH 4 + -N and NO 2 - -N removal rate reached 95%, and total nitrogen removal rate reached 82%.

[0046] ④ Stage IV (cycles 181-240), during this stage NH 4 + -N and NO 2 - -N influent concentration is 40mg / L, and the average nitrogen load is 0.41kgN / (m3 ·d), initially due to the increase in load, NH 4 + -N and NO 2 - -N removal rate is 80%, 75%, total nitrogen removal rate is about 70%, and the removal rate gradually increases with the increase of cycle number. 4 + -N and NO 2 - The -N removal rate is about 85%, and the total nitrogen removal rate is stable at 76%.

[0047] ⑤ Stage V (241-300 cycles), during this stage NH 4 + -N and NO 2 - -N influent concentration is 40mg / L, average nitrogen load is 0.46kgN / (m 3 ·d), continue to reduce the hydraulic retention time to 4.5h, after long-term acclimatization, NH 4 + -N and NO 2 - -N removal rate is about 85%, total nitrogen removal rate is stable at 78%, and NO 3 - The -N concentration increased by an average of 6.9 mg / L, the activity of anaerobic ammonium oxidizing bacteria was enhanced, and the enrichment of anaerobic ammonium oxidizing bacteria was successfully achieved.

[0048] like Figure 2 As shown in the figure, after the experimental operation, the proportion of anaerobic ammonia-oxidizing bacteria Candidatus-kuenenia increased from 2.5% at the beginning of the experiment to 17.9% at the end of the experiment.

[0049] (5) Convert simulated wastewater into actual wastewater that needs to be treated and operate it stably for a long time.

[0050] On the basis of the above-mentioned Example 1, only the discharge water ratio was changed, and the experiment was conducted again. The results are shown in the following table:

[0051] Serial number Drainage ratio Average total nitrogen removal rate 1 20％ 42.8％ 2 30％ 55.6％ 3 40％ 70.8％ 4 50％ 78.8％ 5 60％ 76.7％ 6 70％ 62.1％

[0052] The above table shows that adopting a drainage ratio of 40-60% has better technical effects.

[0053] On the basis of the above Example 1, only the stirring reaction time was changed, and the experiment was conducted again. The results are shown in the following table:

[0054] For stage I, NH 4 + -N and NO 2 --N inlet concentrations are 30mg / L and 40mg / L respectively;

[0055] Serial number Stirring reaction time Average total nitrogen removal rate 1 7h 52％ 2 7.5h 60.2％ 3 8h 65％ 4 8.5h 64.8％ 5 9h 65.4％

[0056] For Phase II, NH 4 + -N and NO 2 - -N inlet concentrations were 30mg / L and 30mg / L respectively;

[0057]

[0058]

[0059] For Phase III, NH 4 + -N and NO 2 - The -N inlet concentrations were 30 mg / L and 30 mg / L respectively. As the system had been acclimated in the early stage, it gradually adapted to the changes in low HRT.

[0060] Serial number Stirring reaction time Average total nitrogen removal rate 1 4h 73.4％ 2 4.5h 78.6％ 3 5h 82％ 4 5.5h 81.2％ 5 6h 83％

[0061] For stage IV, NH 4 + -N and NO 2 - -N inlet concentrations are 40mg / L and 40mg / L respectively

[0062] Serial number Stirring reaction time Average total nitrogen removal rate 1 4h 69.8％ 2 4.5h 73.4％ 3 5h 76.2％ 4 5.5h 64.8％ 5 6h 65.4％

[0063] For stage V, NH 4 + -N and NO 2 - -N inlet concentrations are 40mg / L and 40mg / L respectively

[0064]

[0065]

[0066] The above table shows that for the above five stages, the stirring reaction times are 8h, 6h, 5h, 5h, and 4.5h, respectively, which has a very good technical effect.

[0067] The present invention is not limited to the above-mentioned embodiments. On the basis of the technical solution disclosed in the present invention, technicians in this field can make some substitutions and deformations to some technical features therein according to the disclosed technical content without creative labor, and these substitutions and deformations are all within the protection scope of the present invention.

Claims

1. A method for rapid enrichment of anaerobic ammonia-oxidizing bacteria by combined regulation of NLR and HRT, characterized in that The steps include: (1) Selection of inoculated sludge and reactor and setting of experimental parameters: The SBR reactor was inoculated with anaerobic ammonium-oxidizing floc sludge, the reactor inlet water was artificial simulated wastewater, the water temperature in the reactor was stabilized at 29-35°C, the pH was controlled between 7.4-8.4, and the dissolved oxygen concentration was controlled between 0-0.4 mg / L; the outside of the reactor was covered with a shade cloth to protect the reactor from light; (2) The simulated wastewater was treated in several cycles using an SBR reactor. Each treatment cycle included: inlet, reaction, sedimentation, outlet and idle, which were cyclically carried out. The SBR reactor operated in five stages in total. Stage I was the activity recovery period. When the ammonia nitrogen and nitrite removal rates reached 80%, the inlet substrate concentration and hydraulic retention time were adjusted to proceed to stage II. When the ammonia nitrogen and nitrite removal rates reached a stable value, the hydraulic retention time was adjusted to increase the nitrogen load to proceed to stage III. After the ammonia nitrogen and nitrite removal rates reached a stable value, the inlet substrate concentration was increased to increase the nitrogen load to proceed to stage IV. After the ammonia nitrogen and nitrite removal rates reached a stable value, the hydraulic retention time was further reduced to increase the nitrogen load to proceed to stage V. When the ammonia nitrogen and nitrite removal rates reached a stable value, the reactor was operated until the ammonia nitrogen and nitrite removal rates of the reactor were greater than 80% and the total nitrogen removal rate was more than 75%. (3) Convert simulated wastewater into actual wastewater that needs to be treated and maintain long-term stable operation.

2. The method for rapid enrichment of anaerobic ammonia-oxidizing bacteria by combined regulation of NLR and HRT according to claim 1, characterized in that: In step (2), the SBR reactor is operated for 2 cycles per day. In each cycle, water is introduced for 15-25 minutes, the stirring reaction time is 4.5-8 hours, the static sedimentation time is 45-75 minutes, the drainage time is 15-25 minutes, and the rest is idle time. The drainage ratio is 40-60%, and the sludge is not actively discharged during the operation of the reactor.

3. The method for rapid enrichment of anaerobic ammonia-oxidizing bacteria by combined regulation of NLR and HRT according to claim 1, characterized in that: The MLSS of anaerobic ammonium oxidation flocculent sludge is 3300 mg / L, and the inoculation amount accounts for one-fifth of the volume of the SBR reactor.

4. The method for rapid enrichment of anaerobic ammonia-oxidizing bacteria by combined regulation of NLR and HRT according to claim 1, characterized in that: The simulated wastewater influent matrix is ​​provided by NH4Cl and NaNO2, and the components of the simulated wastewater are: NH 4+ -N, 30-40mg / L; NO 2- -N, 30-40mg / L; KH2PO4, 20mg / L; NaHCO3, 500mg / L.

5. The method for rapid enrichment of anaerobic ammonia-oxidizing bacteria by combined regulation of NLR and HRT according to claim 1, characterized in that: Trace elements I and II are added to the simulated wastewater every day, the components of trace element I are Na2-EDTA·2H2O, 5000mg / L; FeSO4·7H2O, 5000mg / L; the components of trace element II are Na2-EDTA·2H2O, 15000mg / L; ZnSO4·7H2O, 420mg / L; CoCl2·6H2O, 240mg / L; MnCl2·4H2O, 1000mg / L; CuSO4·5H2O, 250mg / L; NaMoO4·2H2O, 250mg / L; NiCl2·6H2O, 200mg / L; Na2SeO4, 250mg / L; H3BO3, 15mg / L; the daily addition amount of trace elements I and II is 1 / 5000-1 / 20000 of the total weight of the water body on that day.

6. A method for rapid enrichment of anaerobic ammonia-oxidizing bacteria by combined regulation of NLR and HRT according to any one of claims 1 to 4, characterized in that: In step (2), the reactor runs for a total of 300 cycles, and the corresponding five stages are: Phase I: Run 1-60 cycles, NH 4+ -N inlet concentration is 30mg / L, NO 2- -N influent concentration is 40mg / L, and the hydraulic retention time in this stage is 8h; Phase II: Run 61-120 cycles; NH 4+ -N, NO 2- -N influent concentration is 30mg / L, hydraulic retention time is 6h; Phase III: Run 121-180 cycles; NH 4+ -N, NO 2- -N influent concentration remains unchanged at 30 mg / L, and the hydraulic retention time is adjusted to 5 h; Phase IV: Run 181-240 cycles; adjust NH 4+ -N, NO 2- -N influent concentration was 40 mg / L, and hydraulic retention time remained unchanged at 5 h; Phase V: Run for 241-300 cycles; the inlet ammonia nitrogen concentration remains unchanged and the hydraulic retention time is adjusted to 4.5h.

7. The method for rapid enrichment of anaerobic ammonia-oxidizing bacteria by combined regulation of NLR and HRT according to claim 6, characterized in that: The DO and pH changes in the reactor were monitored in real time through an online control system, and the water temperature was controlled at 29-35°C by a heating rod.

Images