Autotrophic denitrifying bacteria combined enrichment culture device and method

Abstract

This invention belongs to the field of industrial wastewater treatment and relates to a device and method for the combined enrichment and cultivation of autotrophic denitrifying bacteria. The device includes: an inlet tank, an anaerobic reactor No. 1, a return tank, and an anoxic reactor No. 2. The inlet tank is equipped with an inlet outlet pipeline connected to the anaerobic reactor No. 1. The anaerobic reactor No. 1 is equipped with an outlet pipeline connected to the return tank. The return tank has an outlet pipeline at its upper part and a return pipeline at its bottom, connected to the anoxic reactor No. 2, which in turn is connected to the anaerobic reactor No. 1. The anoxic reactor No. 2 has a return pipeline at its bottom, connected to the lower part of the return tank. This invention promotes the anaerobic ammonia oxidation and denitrification reactions, enabling rapid start-up of the anaerobic ammonia oxidation reaction and effectively preventing sludge runoff.

Description

Technical Field

[0001] This invention belongs to the field of industrial wastewater treatment, specifically relating to a device and method for the combined enrichment and cultivation of autotrophic denitrifying bacteria. Background Technology

[0002] Nitrogen pollution in my country's water bodies is becoming increasingly serious. Excessive nitrogen discharge into receiving water bodies can lead to a series of problems such as oxygen depletion, black and odorous water, and eutrophication. Developing efficient and low-consumption wastewater denitrification technologies has become an urgent task in the field of pollution control.

[0003] Ammonia nitrogen removal can be achieved through physicochemical and biological methods. Considering cost and removal efficiency, biological methods are generally used in engineering projects. Traditional biological treatment mainly includes two steps: nitrification and denitrification. The nitrification process is mainly completed by ammonifying bacteria, nitrite-oxidizing bacteria, and nitrifying bacteria under aerobic conditions. Ammonia nitrogen in the water is converted into nitrate nitrogen through the action of nitrite-oxidizing and nitrifying bacteria. During denitrification, denitrifying bacteria use organic matter as electron donors to reduce nitrate nitrogen to nitrogen gas under anaerobic conditions.

[0004] Anaerobic ammonia oxidation (AAO) utilizes anaerobic bacteria to convert nitrite and ammonia nitrogen into nitrogen gas. Compared to traditional nitrification and denitrification processes, AAO has advantages such as a shorter reaction pathway, no need for additional carbon sources, no need for alkalinity compensation, and low energy consumption, making it a promising technology with broad application prospects. It has become a hot topic in research on novel biological wastewater denitrification technologies. However, this process has a drawback: the maximum total nitrogen removal rate is approximately 89%, and over 11% of the influent total nitrogen is converted to nitrate nitrogen, potentially leading to substandard effluent total nitrogen levels.

[0005] Currently, two main approaches are used to achieve rapid start-up of the anaerobic ammonia oxidation process: one is to cultivate a biofilm to effectively retain anaerobic ammonia oxidizing bacteria within the biofilm, ensuring a high concentration of microorganisms in the reactor; the other is to granulate the inoculated sludge, so that the enriched products with anaerobic ammonia oxidation activity are retained in the reactor, effectively reducing sludge loss.

[0006] In integrated systems, both reaction stages take place within a single reactor, with two types of functional bacteria (AOB and AnAOB) coexisting. Therefore, strict aeration control is necessary. Furthermore, due to the coexistence of multiple microbial populations, the reactor start-up time is relatively long, making it susceptible to load shocks and potentially leading to system instability. However, integrated systems offer advantages such as low construction costs, small footprint, high volumetric load, and effective avoidance of inhibitory effects caused by nitrite accumulation, making them more widely used in engineering applications.

[0007] Compared to integrated systems, two-stage systems offer more flexible and stable operation as the reactors can be independently adjusted and controlled. Separating the two reaction stages of autotrophic nitrogen removal not only optimizes the enrichment of AOB and AnAOB but also eliminates some toxic organic pollutants, preventing toxic substances and organic matter from directly entering the subsequent anaerobic ammonia oxidation reactor. However, two-stage systems have higher investment costs and higher NO content. 2－ -N tends to accumulate, producing free nitrite which has an inhibitory effect, making the system design more complex. Summary of the Invention

[0008] To address the shortcomings of existing technologies, this invention provides a device and method for the combined enrichment and cultivation of autotrophic denitrifying bacteria, which can achieve rapid start-up of anaerobic ammonia oxidation reaction, while simultaneously enriching and cultivating denitrifying bacteria and reducing sludge loss within the anaerobic ammonia oxidation reactor.

[0009] To achieve the above objectives, a first aspect of the present invention provides an autotrophic denitrifying bacteria co-enrichment culture device, comprising an inlet tank, an anaerobic reactor No. 1, a reflux tank, and an anoxic reactor No. 2.

[0010] The water inlet tank is used for mixing and adjusting the water components, and it is equipped with a water inlet tank outlet pipeline, which is connected to anaerobic reactor No. 1.

[0011] The No. 1 anaerobic reactor is used for the start-up, cultivation, and enrichment of anaerobic ammonia-oxidizing bacteria. It is equipped with an effluent pipeline of the No. 1 anaerobic reactor, which is connected to a reflux tank.

[0012] The reflux tank is used for gas discharge and collection. It is equipped with a reflux tank outlet pipeline at the top and a reflux tank return pipeline at the bottom. The reflux tank outlet pipeline is connected to the No. 2 anoxic reactor, and the reflux tank return pipeline is connected to the No. 1 anaerobic reactor.

[0013] The No. 2 anoxic reactor is used to intercept the anaerobic ammonia oxidation granular sludge carried by the effluent of the No. 1 anaerobic reactor, and to further enrich denitrifying bacteria in conjunction with aerobic denitrification. The bottom of the No. 2 anoxic reactor is equipped with a return pipeline, which is connected to the lower part of the return tank.

[0014] A second aspect of the present invention provides a method for the co-enrichment culture of autotrophic denitrifying bacteria, the method being carried out using the aforementioned co-enrichment culture device for autotrophic denitrifying bacteria, and comprising the following steps:

[0015] S1, Bacterial Culture Initiation Phase:

[0016] Step 1: Add the substances required for the anaerobic ammonia oxidation reaction to the inlet tank, inoculate the first activated sludge into the No. 1 anaerobic reactor, start the inlet tank to fill water and empty the air in the No. 1 anaerobic reactor, start the cultivation and acclimatization of anaerobic ammonia oxidizing bacteria, and the nitrogen and water produced by the No. 1 anaerobic reactor enter the return tank.

[0017] Step 2: Inoculate the second activated sludge into the No. 2 anoxic reactor. The effluent from the return tank enters the No. 2 anoxic reactor. The anaerobic ammonia oxidation granular sludge carried out with the effluent from the return tank is intercepted. Intermittent aeration keeps the No. 2 anoxic reactor in anoxic state. Under anoxic state, nitrogen is further removed and denitrifying bacteria are cultivated through anaerobic ammonia oxidation and denitrification.

[0018] Step 3: The sludge at the bottom of the No. 2 anoxic reactor is returned to the return tank, where it settles before being returned to the No. 1 anaerobic reactor.

[0019] S2, the enrichment stage of bacteria:

[0020] Step 4: Monitor the concentrations of ammonia nitrogen, nitrite nitrogen, and nitrate nitrogen in the effluent. When the total nitrogen removal rate of the effluent from anaerobic reactor No. 1 is greater than 60%, and the removal rates of nitrite nitrogen and ammonia nitrogen are greater than 65%, the anaerobic ammonia oxidizing bacteria culture is successfully started. Then, gradually increase the total nitrogen load of the influent, with the total nitrogen amount increasing by 50-120 mg / L in increments of 7-14 days, until the removal rates of nitrite nitrogen and ammonia nitrogen reach more than 80% and anaerobic reactor No. 1 turns noticeably red, the enrichment of anaerobic ammonia oxidizing bacteria is complete.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] (1) This invention can effectively solve the problem of sludge loss caused by sludge run-off during the start-up phase of anaerobic ammonia oxidation bacteria. First, by adding a return port and a return tank, the reactor can effectively intercept the sludge carried out with the water flow while discharging the nitrogen gas generated by the reaction. After the sludge settles in the return tank, it is returned to the reactor by the return pump. Second, a No. 2 anoxic reactor is added to intercept the anaerobic ammonia oxidation granular sludge. In the No. 2 anoxic reactor, aerobic activated sludge and anaerobic granular sludge coexist. The aerobic sludge wraps around the anaerobic granular sludge and then flows back to the No. 1 anaerobic reactor, which effectively avoids sludge run-off and can simultaneously enrich denitrifying bacteria.

[0023] (2) This invention starts the culture of anaerobic ammonia oxidation dominant bacteria under low load conditions, increases the total nitrogen load through gradient increase, rapidly enriches anaerobic ammonia oxidation bacteria, and the anaerobic ammonia oxidation reaction and denitrification reaction promote each other, which can realize the rapid start-up of anaerobic ammonia oxidation reaction.

[0024] Other features and advantages of the present invention will be described in detail in the following detailed description section. Attached Figure Description

[0025] Exemplary embodiments of the present invention will be described in more detail with reference to the accompanying drawings.

[0026] Figure 1 A schematic diagram of the autotrophic denitrifying bacteria co-culture device of the present invention is shown. Detailed Implementation

[0027] The following provides a detailed description of specific embodiments of the present invention. It should be understood that the specific embodiments described herein are for illustrative and explanatory purposes only and are not intended to limit the scope of the invention.

[0028] To achieve the above objectives, a first aspect of the present invention provides an autotrophic denitrifying bacteria co-enrichment culture device, comprising an inlet tank, an anaerobic reactor No. 1, a reflux tank, and an anoxic reactor No. 2.

[0029] The water inlet tank is used for mixing and adjusting the water components, and it is equipped with a water inlet tank outlet pipeline, which is connected to anaerobic reactor No. 1.

[0030] The No. 1 anaerobic reactor is used for the start-up, cultivation, and enrichment of anaerobic ammonia-oxidizing bacteria. It is equipped with an effluent pipeline of the No. 1 anaerobic reactor, which is connected to a reflux tank.

[0031] The reflux tank is used for gas discharge and collection. It is equipped with a reflux tank outlet pipeline at the top and a reflux tank return pipeline at the bottom. The reflux tank outlet pipeline is connected to the No. 2 anoxic reactor, and the reflux tank return pipeline is connected to the No. 1 anaerobic reactor.

[0032] The No. 2 anoxic reactor is used to intercept the anaerobic ammonia oxidation granular sludge carried by the effluent of the No. 1 anaerobic reactor, and to further enrich denitrifying bacteria in conjunction with aerobic denitrification. The bottom of the No. 2 anoxic reactor is equipped with a return pipeline, which is connected to the lower part of the return tank.

[0033] In this invention, because the No. 1 reactor is unstable in the initial stage of startup and sludge leakage occurs frequently, the No. 2 reactor mainly plays a role in intercepting anaerobic ammonia oxidation granular sludge during this stage. In the No. 2 reactor, aerobic activated sludge and anaerobic granular sludge coexist. The aerobic sludge coats the anaerobic granular sludge. After sedimentation in the return tank, it is returned to the No. 1 reactor, thereby effectively avoiding sludge leakage.

[0034] According to the present invention, preferably, pumps are installed on the water inlet tank outlet pipeline, the return tank return pipeline, and the No. 2 anoxic reactor return pipeline.

[0035] According to the present invention, preferably, the No. 1 anaerobic reactor is an upflow reactor equipped with a stirrer and a sealed cover; the No. 2 anoxic reactor is a cone-bottom upflow reactor equipped with a stirrer.

[0036] According to the present invention, preferably, both reactor No. 1 and reactor No. 2 are filled with packing material.

[0037] Preferably, the filler is polyurethane foam, and preferably, the average porosity of the polyurethane foam is >85%.

[0038] In this invention, the polyurethane foam used is 1-2 cm in size. 3 .

[0039] A second aspect of the present invention provides a method for the co-enrichment culture of autotrophic denitrifying bacteria, the method being carried out using the aforementioned co-enrichment culture device for autotrophic denitrifying bacteria, and comprising the following steps:

[0040] S1, Bacterial Culture Initiation Phase:

[0041] Step 1: Add the substances required for the anaerobic ammonia oxidation reaction to the inlet tank, inoculate the first activated sludge into the No. 1 anaerobic reactor, start the inlet tank to fill water and empty the air in the No. 1 anaerobic reactor, start the cultivation and acclimatization of anaerobic ammonia oxidizing bacteria, and the nitrogen and water produced by the No. 1 anaerobic reactor enter the return tank.

[0042] Step 2: Inoculate the second activated sludge into the No. 2 anoxic reactor. The effluent from the return tank enters the No. 2 anoxic reactor. The anaerobic ammonia oxidation granular sludge carried out with the effluent from the return tank is intercepted. Intermittent aeration keeps the No. 2 anoxic reactor in anoxic state. Under anoxic state, nitrogen is further removed and denitrifying bacteria are cultivated through anaerobic ammonia oxidation and denitrification.

[0043] Step 3: The sludge at the bottom of the No. 2 anoxic reactor is returned to the return tank, where it settles before being returned to the No. 1 anaerobic reactor.

[0044] S2, the enrichment stage of bacteria:

[0045] Step 4: Monitor the concentrations of ammonia nitrogen, nitrite nitrogen, and nitrate nitrogen in the effluent. When the total nitrogen removal rate of the effluent from anaerobic reactor No. 1 is greater than 60%, and the removal rates of nitrite nitrogen and ammonia nitrogen are greater than 65%, the anaerobic ammonia oxidizing bacteria culture is successfully started. Then, gradually increase the total nitrogen load of the influent, with the total nitrogen amount increasing by 50-120 mg / L in increments of 7-14 days, until the removal rates of nitrite nitrogen and ammonia nitrogen reach more than 80%, the bacterial concentration in anaerobic reactor No. 1 increases to 0.8-1.5 g / L, and anaerobic reactor No. 1 turns noticeably red, the enrichment of anaerobic ammonia oxidizing bacteria is complete.

[0046] In this invention, the No. 2 anoxic reactor is a denitrification reactor, which can simultaneously denitrify using upstream sludge. The effluent from the anaerobic ammonium oxidation reaction contains a large amount of nitrate, which is the nitrogen source for denitrification. The two do not compete with each other. In the No. 2 anoxic reactor, aerobic activated sludge and anaerobic granular sludge coexist. The aerobic sludge coats the anaerobic granular sludge and is then returned to the No. 1 anaerobic reactor, thus effectively avoiding sludge loss. Moreover, the anaerobic ammonium oxidation reaction and the denitrification reaction promote each other, enabling the rapid start-up of the anaerobic ammonium oxidation reaction.

[0047] According to the present invention, preferably, the total nitrogen content increases in increments of 80 to 100 mg / L.

[0048] According to the present invention, preferably, the first activated sludge and the second activated sludge are each independently activated sludge from the secondary sedimentation tank of an industrial wastewater treatment plant.

[0049] In this invention, the activated sludge is taken from the activated sludge of the secondary sedimentation tank of an industrial wastewater (sulfur-containing wastewater) treatment plant, and contains desulfurization bacteria such as anaerobic ammonia oxidizing bacteria, nitrifying bacteria and denitrifying bacteria.

[0050] Preferably, the inoculation concentration of the first activated sludge is 300–500 mg / L.

[0051] Preferably, the inoculation concentration of the second activated sludge is 100–200 mg / L.

[0052] According to the present invention, preferably, the mass ratio of ammonia nitrogen to nitrite nitrogen is 1:0.8 to 1, the mass ratio of total nitrogen to inorganic carbon is 1:0.5 to 0.8, and based on the total weight of the substances required for the anaerobic ammonia oxidation reaction, the content of the other inorganic salts is 1 to 5 wt%, and the content of the micro-liquid is 0.1 to 0.2 wt%.

[0053] Preferably, the other inorganic salt is at least one of calcium salt, magnesium salt and iron salt.

[0054] Preferably, the amount of substances added for the anaerobic ammonia oxidation reaction is such that the total nitrogen concentration in the influent of the influent tank during the start-up phase does not exceed 200 mg / L, the calcium concentration is 0.1–0.2 g / L, the magnesium ion concentration is 0.1–0.2 g / L, and the iron ion concentration is 0.05–0.1 g / L.

[0055] According to the present invention, preferably, the ammonia nitrogen salt is at least one selected from ammonium sulfate, ammonium chloride and ammonium carbonate, and more preferably ammonium chloride.

[0056] Preferably, the nitrite is sodium nitrite and / or potassium nitrite, with sodium nitrite being the most preferred.

[0057] Preferably, the inorganic carbon is a carbonate and / or bicarbonate, more preferably sodium carbonate and / or sodium bicarbonate, and even more preferably sodium bicarbonate.

[0058] Preferably, the calcium salt is calcium chloride.

[0059] Preferably, the magnesium salt is magnesium chloride and / or magnesium sulfate.

[0060] Preferably, the iron salt is ferrous sulfate and / or ferric sulfate.

[0061] According to the present invention, preferably, the micro-liquid contains cobalt chloride, manganese chloride, copper chloride, zinc chloride, boric acid, EDTA, and (NH4)6Mo7O. 24 ·4H2O, Na2SeO3·6H2O and NiCl2.

[0062] Preferably, the concentrations of cobalt chloride, manganese chloride, copper chloride, zinc chloride, boric acid, EDTA, and (NH4)6Mo7O are 0.1–0.2 mg / L, 0.1–0.2 mg / L, 0.05–0.1 mg / L, 0.002–0.005 mg / L, 0.002–0.005 mg / L, 0.05–0.1 mg / L, and (NH4)6Mo7O 24 The concentrations of ·4H2O, Na2SeO3·6H2O, and NiCl2 were 0.005–0.01 mg / L, 0.005–0.01 mg / L, and 0.002–0.005 mg / L, respectively.

[0063] According to the present invention, preferably, the culture initiation phase lasts for 10 to 30 days.

[0064] According to the present invention, preferably, the bacterial concentration in the No. 1 anaerobic reactor is increased to 0.8-1.5 g / L, and the enrichment of anaerobic ammonia oxidizing bacteria is completed.

[0065] According to the present invention, preferably, the size of the No. 1 reactor is 3 to 5 L, and the conditions of the No. 1 reactor include: pH 7.5 to 8.2, dissolved oxygen concentration less than 0.1 mg / L, and temperature 30 to 35 °C.

[0066] According to the present invention, preferably, the second reactor is 1 to 2 L, and the conditions of the second reactor include: pH 7.0 to 8.0, dissolved oxygen concentration 0.5 to 1 mg / L, and temperature 25 to 35°C.

[0067] The present invention will be further described below with reference to the embodiments, but the scope of the present invention is not limited to these embodiments.

[0068] In the following examples, the activated sludge comes from the activated sludge of the secondary sedimentation tank of an industrial wastewater (sulfur-containing wastewater) treatment plant, and contains desulfurization bacteria such as anaerobic ammonia oxidizing bacteria, nitrifying bacteria and denitrifying bacteria.

[0069] Example 1

[0070] In this embodiment, the following is adopted: Figure 1 The autotrophic denitrifying bacteria co-enrichment culture device shown is used, which includes: an inlet tank, an anaerobic reactor No. 1, a reflux tank, and an anoxic reactor No. 2; wherein, the anaerobic reactor No. 1 is an upflow reactor equipped with a stirrer and a sealed cover; the anoxic reactor No. 2 is a cone-bottom upflow reactor equipped with a stirrer, and both the anaerobic reactor No. 1 and the anoxic reactor No. 2 are filled with polyurethane sponge, the size of which is 1-2 cm. 3 The average porosity is 90%.

[0071] The inlet tank is used for mixing and adjusting the inlet components, and it is equipped with an inlet tank outlet pipeline, which is connected to anaerobic reactor No. 1. Anaerobic reactor No. 1 is used for the start-up, cultivation, and enrichment of anaerobic ammonia-oxidizing bacteria, and it is equipped with an anaerobic reactor No. 1 outlet pipeline, which is connected to a return tank. The return tank is used for gas discharge and collection, and it is equipped with a return tank outlet pipeline at the top and a return tank return pipeline at the bottom. The return tank outlet pipeline is connected to an anoxic reactor No. 2, and the return tank return pipeline is connected to anaerobic reactor No. 1. Anoxic reactor No. 2 is used to intercept the anaerobic ammonia-oxidizing granular sludge carried by the effluent from anaerobic reactor No. 1, and to further enrich denitrifying bacteria in conjunction with aerobic denitrification. It is equipped with an anoxic reactor No. 2 return pipeline at the bottom, which is connected to the lower part of the return tank. Pumps are installed on the water inlet tank outlet pipeline, the return tank return pipeline, and the No. 2 anoxic reactor return pipeline.

[0072] The method for combined enrichment culture of autotrophic denitrifying bacteria includes the following steps:

[0073] S1, Bacterial Culture Initiation Phase:

[0074] Step 1: Add the substances required for the anaerobic ammonia oxidation reaction to the influent tank, inoculate 500 mg / L activated sludge into reactor No. 1, start the influent tank to vent the air in reactor No. 1, start the cultivation and acclimatization of anaerobic ammonia oxidizing bacteria, and the nitrogen and water produced by reactor No. 1 enter the return tank.

[0075] Step 2: Inoculate 200 mg / L activated sludge into reactor No. 2. The effluent from the return tank enters reactor No. 2. The anaerobic ammonia oxidation granular sludge carried out with the effluent from the return tank is intercepted. Intermittent aeration is used to keep the reactor in an anoxic state. Under the anoxic state, nitrogen is further removed and denitrifying bacteria are cultivated through anaerobic ammonia oxidation and denitrification.

[0076] Step 3: The sludge at the bottom of reactor No. 2 is returned to the return tank, where it settles before being returned to reactor No. 1.

[0077] During the start-up phase, the influent concentrations were: ammonia nitrogen 50 mg / L, nitrite nitrogen 40 mg / L, inorganic carbon 45 mg / L, calcium ion 0.1 mg / L, magnesium ion 0.1 mg / L, and iron ion 0.07 mg / L. The ammonia nitrogen source was ammonium chloride, the nitrite nitrogen source was sodium nitrite, and the inorganic carbon source was sodium bicarbonate. The influent micro-liquid composition was: cobalt chloride 0.1 mg / L, manganese chloride 0.1 mg / L, copper chloride 0.05 mg / L, zinc chloride 0.005 mg / L, boric acid 0.005 mg / L, EDTA 0.05 mg / L, and (NH₄)₆Mo₇O₇. 24 • 4H₂O 0.005 mg / L, Na₂SeO₃·6H₂O 0.005 mg / L, NiCl₂ 0.005 mg / L. Start-up influent flow rate: 2 L / day. Anaerobic reactor No. 1 has an effective volume of 5 L, a hydraulic retention time of 2.5 days, a dissolved oxygen concentration of 0.05 mg / L, a temperature controlled at 35℃, a pH of 7.6, and a stirring rate of 35 rpm. Anoxic reactor No. 2 has an effective volume of 3 L, a dissolved oxygen concentration of 0.6 mg / L, a temperature controlled at 35℃, and a pH of 7.5.

[0078] S2, the enrichment stage of bacteria:

[0079] Step 4: Daily monitoring of effluent ammonia nitrogen, nitrite nitrogen, and nitrate nitrogen concentrations. After 5 days of system startup, if effluent ammonia nitrogen is less than 1 mg / L and nitrite nitrogen concentration is less than 1 mg / L, gradually increase the influent flow rate and decrease the hydraulic retention time. On the 25th day of startup, with an influent flow rate of 5 L / day and a hydraulic retention time of 24 h, effluent ammonia nitrogen is less than 1 mg / L, nitrite nitrogen concentration is less than 1 mg / L, total nitrogen removal rate is greater than 80%, and both nitrite nitrogen and ammonia nitrogen concentrations are less than 1 mg / L, indicating startup is complete.

[0080] Enrichment culture was conducted using a gradient increase in total nitrogen concentration, with the total nitrogen level increasing by 100 mg / L every 7 days. The concentrations of ammonia nitrogen, nitrite nitrogen, and inorganic carbon in the influent were gradually increased, while other concentrations remained constant. The ratio of ammonia nitrogen, nitrite nitrogen, and inorganic carbon was controlled at 1:0.8:0.5. By day 55, the influent ammonia nitrogen was 290 mg / L, nitrite nitrogen was 200 mg / L, and the total nitrogen concentration was 490 mg / L. The effluent total nitrogen was 47.1 mg / L, achieving a total nitrogen removal rate of 90.38%. The bacterial concentration in anaerobic reactor No. 1 increased to 1 g / L, and the sludge turned noticeably red, indicating that enrichment was complete.

[0081] Example 2

[0082] In this embodiment, the autotrophic denitrifying bacteria co-culture device and method are the same as in Example 1, except that the concentration of ammonia nitrogen in the influent during the start-up phase is 100 mg / L, the concentration of nitrite nitrogen is 80 mg / L, the concentration of inorganic carbon is 94 mg / L, the concentration of calcium ions is 0.2 mg / L, the concentration of magnesium ions is 0.2 mg / L, and the concentration of iron ions is 0.1 mg / L. The ammonia nitrogen is provided by ammonium chloride, the nitrite nitrogen by sodium nitrite, and the inorganic carbon by sodium bicarbonate. The influent micro-liquid consists of cobalt chloride 0.1 mg / L, manganese chloride 0.1 mg / L, copper chloride 0.05 mg / L, zinc chloride 0.005 mg / L, boric acid 0.005 mg / L, EDTA 0.05 mg / L, and (NH4)6Mo7O 24 ·4H2O 0.005mg / L, Na2SeO3·6H2O 0.005mg / L, NiCl2 0.005mg / L.

[0083] The initial influent flow rate is 1 L / day, the effective reactor volume is 5 L, the hydraulic retention time is 5 days, the dissolved oxygen concentration is 0.05 mg / L, the temperature is controlled at 30℃, the pH is 8.0, and the stirring rate is 50 rpm. The second anoxic reactor has an effective volume of 3 L, a dissolved oxygen concentration of 0.5 mg / L, a temperature controlled at 28℃, and a pH of 7.0.

[0084] The concentrations of ammonia nitrogen, nitrite nitrogen, and nitrate nitrogen in the effluent were monitored daily. After 3 days of startup, the effluent ammonia nitrogen concentration was less than 1 mg / L, and the nitrite nitrogen concentration was less than 1 mg / L. The influent flow rate was gradually increased, and the hydraulic retention time was decreased. On the 28th day of startup, the influent flow rate was 5 L / day, the hydraulic retention time was 24 h, the effluent ammonia nitrogen concentration was less than 1 mg / L, the nitrite nitrogen concentration was less than 1 mg / L, and the total nitrogen removal rate was greater than 80%, indicating that startup was complete.

[0085] Enrichment culture was conducted using a gradient increase in total nitrogen concentration. The concentrations of ammonia nitrogen, nitrite nitrogen, and inorganic carbon in the influent were gradually increased in a gradient, with the total nitrogen concentration increasing in the same manner as in Example 1: 100 mg / L for 7 days, while other concentrations remained constant. The ratio of ammonia nitrogen, nitrite nitrogen, and inorganic carbon was controlled at 1:0.8:0.5. By day 60, the influent ammonia nitrogen was 290 mg / L, nitrite nitrogen was 200 mg / L, and the total nitrogen concentration was 490 mg / L. The effluent total nitrogen was 40.67 mg / L, achieving a removal rate of 91.7%. The bacterial concentration in anaerobic reactor No. 1 increased to 1.3 g / L, and the sludge turned noticeably red, indicating that enrichment was complete.

[0086] Example 3

[0087] The only difference between this embodiment and Example 1 is that during the bacterial enrichment phase, the total nitrogen content was increased by 100 mg / L every 10 days.

[0088] On the 80th day of operation, the influent ammonia nitrogen was 290 mg / L, nitrite nitrogen was 200 mg / L, total nitrogen concentration was 490 mg / L, and effluent total nitrogen was 46.8 mg / L, with a removal rate of 90.4%. The bacterial concentration in anaerobic reactor No. 1 increased to 1.2 g / L, and the sludge turned noticeably red, indicating that enrichment was complete.

[0089] Example 4

[0090] The only difference between this embodiment and Example 1 is that during the bacterial enrichment phase, the total nitrogen content was increased by 150 mg / L over 7 days.

[0091] On the 48th day of startup, the influent ammonia nitrogen was 290 mg / L, nitrite nitrogen was 200 mg / L, and total nitrogen concentration was 490 mg / L. The effluent total nitrogen was 82 mg / L, with a removal rate of 83.2%. On the 55th day of startup, the influent ammonia nitrogen was 290 mg / L, nitrite nitrogen was 200 mg / L, and total nitrogen concentration was 490 mg / L. The effluent total nitrogen was 73 mg / L, with a removal rate of 85.1%. The excessive total nitrogen had an inhibitory effect, and the predetermined removal rate was not achieved.

[0092] The various embodiments of the present invention have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments.

[0093] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

Claims

1. A device for combined enrichment culture of autotrophic denitrifying bacteria, characterized in that, The device includes: an inlet tank, an anaerobic reactor No. 1, a reflux tank, and an anoxic reactor No. 2; The water inlet tank is used for mixing and adjusting the water components, and it is equipped with a water inlet tank outlet pipeline, which is connected to anaerobic reactor No.

1. The No. 1 anaerobic reactor is used for the start-up, cultivation, and enrichment of anaerobic ammonia-oxidizing bacteria. It is equipped with an effluent pipeline of the No. 1 anaerobic reactor, which is connected to a reflux tank. The reflux tank is used for gas discharge and collection. It is equipped with a reflux tank outlet pipeline at the top and a reflux tank return pipeline at the bottom. The reflux tank outlet pipeline is connected to the No. 2 anoxic reactor, and the reflux tank return pipeline is connected to the No. 1 anaerobic reactor. The No. 2 anoxic reactor is used to intercept the anaerobic ammonia oxidation granular sludge carried by the effluent of the No. 1 anaerobic reactor, and to further enrich denitrifying bacteria in conjunction with aerobic denitrification. The bottom of the No. 2 anoxic reactor is equipped with a return pipeline, which is connected to the lower part of the return tank.

2. The autotrophic denitrifying bacteria combined enrichment culture device according to claim 1, wherein, Pumps are installed on the water inlet tank outlet pipeline, the return tank return pipeline, and the No. 2 anoxic reactor return pipeline.

3. The autotrophic denitrifying bacteria combined enrichment culture device according to claim 1, wherein, The No. 1 anaerobic reactor is a flat-bottomed upflow reactor equipped with a stirrer and a sealed cover; The No. 2 anoxic reactor is a cone-bottom upflow reactor equipped with a stirrer.

4. The autotrophic denitrifying bacteria combined enrichment culture device according to claim 1, wherein, Both the No. 1 anaerobic reactor and the No. 2 anoxic reactor were filled with packing material.

5. The autotrophic denitrifying bacteria combined enrichment culture device according to claim 4, wherein, The filler is polyurethane foam.

6. The autotrophic denitrifying bacteria co-enrichment culture device according to claim 5, wherein, The average porosity of the polyurethane foam is >85%.

7. A method for combined enrichment culture of autotrophic denitrifying bacteria, characterized by, This method, using the autotrophic denitrifying bacteria co-culture device according to any one of claims 1-6, includes the following steps: S1, Bacterial Culture Initiation Phase: Step 1: Add the substances required for the anaerobic ammonia oxidation reaction to the inlet tank, inoculate the first activated sludge into the No. 1 anaerobic reactor, start the inlet tank to fill water and empty the air in the No. 1 anaerobic reactor, start the cultivation and acclimatization of anaerobic ammonia oxidizing bacteria, and the nitrogen and water produced by the No. 1 anaerobic reactor enter the return tank. Step 2: Inoculate the second activated sludge into the No. 2 anoxic reactor. The effluent from the return tank enters the No. 2 anoxic reactor. The anaerobic ammonia oxidation granular sludge carried out with the effluent from the return tank is intercepted. Intermittent aeration keeps the No. 2 anoxic reactor in anoxic state. Under anoxic state, nitrogen is further removed and denitrifying bacteria are cultivated through anaerobic ammonia oxidation and denitrification. Step 3: The sludge at the bottom of the No. 2 anoxic reactor is returned to the return tank, where it settles before being returned to the No. 1 anaerobic reactor. S2, the enrichment stage of bacteria: Step 4: Monitor the concentrations of ammonia nitrogen, nitrite nitrogen, and nitrate nitrogen in the effluent. When the total nitrogen removal rate of the effluent from anaerobic reactor No. 1 is greater than 70%, and the removal rates of nitrite nitrogen and ammonia nitrogen are greater than 75%, the anaerobic ammonia oxidizing bacteria culture is successfully started. Then, gradually increase the total nitrogen load of the influent, with the total nitrogen amount increasing by 50-120 mg / L in increments of 7-14 days, until the removal rates of nitrite nitrogen and ammonia nitrogen reach more than 90% and anaerobic reactor No. 1 turns noticeably red, the enrichment of anaerobic ammonia oxidizing bacteria is complete.

8. The autotrophic denitrifying bacteria combined enrichment culture method according to claim 7, wherein, The total nitrogen content was increased in increments of 80–100 mg / L.

9. The autotrophic denitrifying bacteria combined enrichment culture method according to claim 7, wherein, The first activated sludge and the second activated sludge are each independently activated sludge from the secondary sedimentation tank of an industrial wastewater treatment plant; The inoculum concentration of the first activated sludge is 300–500 mg / L; The inoculation concentration of the second activated sludge is 100–200 mg / L.

10. The autotrophic denitrifying bacteria combined enrichment culture method according to claim 7, wherein, The substances required for the anaerobic ammonia oxidation reaction are ammonium salt, nitrite, inorganic carbon, other inorganic salts, and micro-liquid. The mass ratio of ammonia nitrogen to nitrite nitrogen is 1:0.8 to 1, and the mass ratio of total nitrogen to inorganic carbon is 1:0.5 to 0.

8. Based on the total weight of the substances required for the anaerobic ammonia oxidation reaction, the content of other inorganic salts is 1 to 5 wt%, and the content of micro-liquid is 0.1 to 0.2 wt%.

11. The autotrophic denitrifying bacteria combined enrichment culture method according to claim 10, wherein, The other inorganic salts are at least one of calcium salts, magnesium salts, and iron salts.

12. The autotrophic denitrifying bacteria combined enrichment culture method according to claim 11, wherein, The amount of substances added for the anaerobic ammonia oxidation reaction is such that the total nitrogen concentration in the influent tank during the start-up phase does not exceed 200 mg / L, the calcium concentration is 0.1–0.2 g / L, the magnesium ion concentration is 0.1–0.2 g / L, and the iron ion concentration is 0.05–0.1 g / L.

13. The autotrophic denitrifying bacteria combined enrichment culture method according to claim 11, wherein, The ammonium salt is at least one of ammonium sulfate, ammonium chloride, and ammonium carbonate; The nitrite is sodium nitrite and / or potassium nitrite; The inorganic carbon is a carbonate and / or a bicarbonate; The calcium salt is calcium chloride; The magnesium salt is magnesium chloride and / or magnesium sulfate; The iron salt is ferrous sulfate and / or ferric sulfate.

14. The method for combined enrichment culture of autotrophic denitrifying bacteria according to claim 13, wherein, The ammonium salt is ammonium chloride.

15. The autotrophic denitrifying bacteria combined enrichment culture method according to claim 13, wherein, The nitrite is sodium nitrite.

16. The autotrophic denitrifying bacteria combined enrichment culture method according to claim 13, wherein, The inorganic carbon is sodium carbonate and / or sodium bicarbonate.

17. The autotrophic denitrifying bacteria combined enrichment culture method according to claim 16, wherein, The inorganic carbon is sodium bicarbonate.

18. The autotrophic denitrifying bacteria combined enrichment culture method according to claim 10, wherein, The microsolution contains cobalt chloride, manganese chloride, copper chloride, zinc chloride, boric acid, EDTA, and (NH4)6Mo7O. 24 ·4H2O, Na2SeO3·6H2O and NiCl2.

19. The autotrophic denitrifying bacteria combined enrichment culture method according to claim 18, wherein, The concentrations of cobalt chloride, manganese chloride, copper chloride, zinc chloride, boric acid, and EDTA were 0.05–0.1 mg / L, 0.002–0.005 mg / L, 0.002–0.005 mg / L, and 0.05–0.1 mg / L, respectively. 24 The concentrations of ·4H2O, Na2SeO3·6H2O, and NiCl2 were 0.005–0.01 mg / L, 0.005–0.01 mg / L, and 0.002–0.005 mg / L, respectively.

20. The autotrophic denitrifying bacteria combined enrichment culture method according to claim 7, wherein, The initiation phase of the culture lasts for 10 to 30 days.

21. The method for combined enrichment culture of autotrophic denitrifying bacteria according to claim 7, wherein, Once the bacterial concentration in the No. 1 anaerobic reactor increases to 0.8~1.5 g / L, the enrichment of anaerobic ammonia oxidizing bacteria is complete.

22. The method for combined enrichment culture of autotrophic denitrifying bacteria according to claim 7, wherein, The volume of the No. 1 anaerobic reactor is 3-5L. The control conditions of the No. 1 anaerobic reactor include: pH 7.5-8.2, dissolved oxygen concentration less than 0.1mg / L, and temperature 30-35℃. The volume of the No. 2 anoxic reactor is 1-2L. The control conditions of the No. 2 anoxic reactor include: pH 7.0-8.0, dissolved oxygen concentration 0.5-1mg / L, and temperature 25-35℃.

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