Iron autotrophic denitrification coupled with anaerobic ammonia oxidation combined enrichment culture device and method

Abstract

This invention belongs to the field of industrial wastewater treatment and relates to a combined enrichment and cultivation device and method for iron autotrophic denitrification coupled with anaerobic ammonia oxidation. It includes: an inlet tank, a No. 1 anoxic reactor, an intermediate tank, and a No. 2 anaerobic reactor; the inlet tank is equipped with an inlet outlet pipeline connected to the No. 1 anoxic reactor; the No. 1 anoxic reactor is equipped with a No. 1 anoxic reactor outlet pipeline connected to the intermediate tank; the intermediate tank is equipped with an intermediate tank outlet pipeline connected to the No. 2 anaerobic reactor; the No. 2 anaerobic reactor is equipped with a No. 2 anaerobic reactor outlet pipeline connected to the No. 1 anoxic reactor. This invention enables the co-cultivation of autotrophic denitrifying bacteria and anaerobic ammonia oxidizing bacteria. The autotrophic denitrification provides a certain amount of nitrite and iron ions to promote the anaerobic ammonia oxidation reaction, while the anaerobic ammonia oxidation effectively prevents mineralization in the autotrophic denitrification tank.

Description

Technical Field

[0001] This invention belongs to the field of industrial wastewater treatment, specifically relating to an iron autotrophic denitrification coupled with anaerobic ammonia oxidation co-enrichment culture device and method. Background Technology

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

[0003] Anaerobic ammonia oxidation (AAO) utilizes anaerobic ammonia-oxidizing bacteria to convert nitrite and ammonia nitrogen into nitrogen gas. Compared with 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. It has broad application prospects and has become a hot topic in the research of new biological wastewater denitrification technologies.

[0004] Autotrophic denitrification requires no added organic carbon source. Autotrophic denitrifying bacteria use hydrogen, reduced sulfides, or iron salts as electron donors and inorganic carbon as the carbon source to reduce nitrates to nitrogen. Furthermore, the low growth rate of autotrophic microorganisms effectively reduces sludge production and the risk of secondary pollution. Autotrophic denitrification using iron as a medium can simultaneously remove nitrates and form Fe... 3+ The precipitate is used to recover iron. The reaction principle involves autotrophic denitrifying bacteria converting Fe... 2+ Oxidized to Fe 3+ Then through Fe 3+ Pollutants are removed through precipitation or adsorption of hydroxides, oxides, and other metals. Electrons are transferred to nitrates, which are then anaerobically reduced to nitrogen gas through denitrification. Most studies have demonstrated that nitrates in iron-based autotrophic denitrification systems are completely reduced to N2 and released without the accumulation of intermediate products. Some studies have found that this process generates large amounts of nitrites and nitrous oxide. Summary of the Invention

[0005] To address the aforementioned problems in the existing technology, this invention provides an iron autotrophic denitrification coupled with anaerobic ammonia oxidation co-enrichment culture device and method, which can simultaneously enrich and culture anaerobic ammonia oxidizing bacteria and autotrophic denitrifying bacteria, and can also achieve rapid start-up of anaerobic ammonia oxidizing bacteria culture.

[0006] To achieve the above objectives, a first aspect of the present invention provides an iron autotrophic denitrification coupled with anaerobic ammonia oxidation co-enrichment culture device, comprising: an inlet tank, an anoxic reactor No. 1, an intermediate tank, and an anaerobic reactor No. 2.

[0007] The inlet tank is used for mixing and adjusting the inlet components of the No. 1 anoxic reactor. It is equipped with an outlet pipeline, which is connected to the No. 1 anoxic reactor.

[0008] The No. 1 anoxic reactor is used for the cultivation and enrichment of iron-autotrophic denitrifying bacteria. It is equipped with an outlet pipeline of the No. 1 anoxic reactor, which is connected to the intermediate tank.

[0009] The intermediate tank is used for mixing and adjusting the influent components of anaerobic reactor No. 2. It is equipped with an intermediate tank outlet pipeline, which is connected to anaerobic reactor No. 2.

[0010] The No. 2 anaerobic reactor is used for the start-up, cultivation, and enrichment of anaerobic ammonia-oxidizing bacteria. It is equipped with a No. 2 anaerobic reactor effluent pipeline, which is connected to the No. 1 anoxic reactor.

[0011] A second aspect of the present invention provides a method for the combined enrichment culture of iron autotrophic denitrification coupled with anaerobic ammonia oxidation, comprising the following steps:

[0012] S1, Bacterial Culture Initiation Phase

[0013] Step 1: Add the substances required for iron autotrophic denitrification to the inlet tank, inoculate the first activated sludge into the No. 1 anoxic reactor, start the inlet tank to drain the air in the No. 1 anoxic reactor, add 8-10g of iron powder, and start the cultivation and acclimatization of iron autotrophic denitrification bacteria under anoxic conditions.

[0014] Step 2: The effluent from the No. 1 anoxic reactor enters the intermediate tank, where the substances required for the anaerobic ammonia oxidation reaction are added and mixed thoroughly.

[0015] Step 3: Inoculate the second activated sludge into anaerobic reactor No. 2. The effluent from the intermediate tank enters anaerobic reactor No. 2. Under anoxic or anaerobic conditions, denitrification and enrichment of anaerobic ammonia-oxidizing bacteria are carried out.

[0016] S2, the bacterial enrichment stage

[0017] Step 4: Monitor the concentrations of ammonia nitrogen, nitrite nitrogen, and nitrate nitrogen in the effluent of Anoxic Reactor No. 1. The nitrate removal rate in the effluent of Anoxic Reactor No. 1 is greater than 70%, and ammonia and nitrite appear in the effluent, indicating that the iron autotrophic denitrification has been successfully started. Then, increase the nitrate nitrogen load in the influent of Anoxic Reactor No. 1 and add iron powder. The nitrate nitrogen load is increased in increments of 50-80 mg / L, and the amount of iron powder added is 3-5 g / 10 days.

[0018] Step 5: Monitor the concentrations of ammonia nitrogen, nitrite nitrogen, and nitrate nitrogen in the effluent of anaerobic reactor No. 2. If the total nitrogen removal rate of the effluent from anaerobic reactor No. 2 is greater than 60%, and the removal rates of nitrite nitrogen and ammonia nitrogen are greater than 70%, the anaerobic ammonia-oxidizing bacteria culture has been successfully started. Then, gradually increase the total nitrogen load of the influent to anaerobic reactor No. 2, increasing the total nitrogen content in increments of 50–120 mg / L over a period of 7–14 days, until the removal rates of nitrite nitrogen and ammonia nitrogen reach over 90% and anaerobic reactor No. 2 turns noticeably red, the enrichment is complete.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] (1) The present invention can achieve rapid start-up of anaerobic ammonia oxidation reaction, start-up culture of dominant anaerobic ammonia oxidation bacteria under low load, increase total nitrogen load through gradient increase, and rapidly enrich anaerobic ammonia oxidation bacteria.

[0021] (2) The present invention can realize the co-cultivation of autotrophic denitrifying bacteria and anaerobic ammonia oxidizing bacteria. The autotrophic denitrification consumes dissolved oxygen in the influent to provide anaerobic conditions for anaerobic ammonia oxidation and provides a certain amount of nitrite and iron ions to promote the anaerobic ammonia oxidation reaction. The product water of anaerobic ammonia oxidation can be effectively prevented from mineralization and promoted by returning it to the autotrophic denitrification tank.

[0022] Other features and advantages of the present invention will be described in detail in the following detailed description section. Attached Figure Description

[0023] Exemplary embodiments of the present invention will be described in more detail with reference to the accompanying drawings.

[0024] Figure 1 A schematic diagram of the iron autotrophic denitrification coupled with anaerobic ammonium oxidation enrichment culture device of the present invention is shown. Detailed Implementation

[0025] 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.

[0026] To achieve the above objectives, a first aspect of the present invention provides an iron autotrophic denitrification coupled with anaerobic ammonia oxidation co-enrichment culture device, comprising: an inlet tank, an anoxic reactor No. 1, an intermediate tank, and an anaerobic reactor No. 2.

[0027] The inlet tank is used for mixing and adjusting the inlet components of the No. 1 anoxic reactor. It is equipped with an outlet pipeline, which is connected to the No. 1 anoxic reactor.

[0028] The No. 1 anoxic reactor is used for the cultivation and enrichment of iron-autotrophic denitrifying bacteria. It is equipped with an outlet pipeline of the No. 1 anoxic reactor, which is connected to the intermediate tank.

[0029] The intermediate tank is used for mixing and adjusting the influent components of anaerobic reactor No. 2. It is equipped with an intermediate tank outlet pipeline, which is connected to anaerobic reactor No. 2.

[0030] The No. 2 anaerobic reactor is used for the start-up, cultivation, and enrichment of anaerobic ammonia-oxidizing bacteria. It is equipped with a No. 2 anaerobic reactor effluent pipeline, which is connected to the No. 1 anoxic reactor.

[0031] In this invention, the feed tank and neutralization tank are used for adjusting the proportions of various substances in the influent, mixing them, monitoring pH and dissolved oxygen, and adjusting them in a timely manner. Anoxic reactor No. 1 is used for the cultivation and enrichment of iron-autotrophic denitrifying bacteria and to intercept the anaerobic ammonia oxidation granular sludge carried by the effluent from reactor No. 2, consuming dissolved oxygen. Anaerobic reactor No. 2 is used for the start-up, cultivation, and enrichment of anaerobic ammonia oxidation bacteria. A reflux device is used to return the liquid from reactor No. 2 to reactor No. 1, and simultaneously for the discharge and collection of gas. Gas and liquid are discharged simultaneously from the reflux port at the top of the reactor. Water and activated sludge are returned to reactor No. 1 via a reflux pump, while gas plays a role in aeration and mixing in reactor No. 1 and escapes into the atmosphere through the open reactor No. 1.

[0032] The current challenges of anaerobic ammonium oxidation (ANAO) lie in its slow and unstable start-up, often accompanied by sludge runoff. Iron-autotrophic denitrification, on the other hand, is prone to mineralization, with iron compounds encapsulating the sludge and slowing mass transfer. A certain amount of anaerobic sludge can effectively address this mineralization issue. Anaerobic ammonium oxidation bacteria require a strictly anaerobic environment for cultivation. The influent carries a certain amount of dissolved oxygen, leading to slow start-up. Autotrophic denitrification, being an anaerobic reaction, effectively consumes dissolved oxygen in the influent, and a certain amount of iron ions promotes ANAO. Furthermore, the byproduct nitrite produced in the autotrophic denitrification system can be further removed through ANAO. Therefore, the two processes have a good synergistic effect. Utilizing autotrophic denitrification coupled with ANAO allows for the simultaneous enrichment of both autotrophic denitrifying and anaerobic ammonium oxidizing bacteria, while also enabling rapid start-up of ANAO experiments.

[0033] According to the present invention, preferably, the bottom of the No. 1 anoxic reactor is provided with a bottom reflux pipeline, and the No. 2 anaerobic reactor is provided with a bottom reflux pipeline.

[0034] Preferably, pumps are installed on the water inlet tank outlet pipeline, the bottom return pipeline of the No. 1 anoxic reactor, the water outlet pipeline of the intermediate tank, the water outlet pipeline of the No. 2 anaerobic reactor, and the bottom return pipeline of the No. 2 anaerobic reactor.

[0035] According to the present invention, preferably, the No. 1 anoxic reactor is an upflow reactor equipped with a three-phase separation device and a stirrer.

[0036] According to the present invention, preferably, the No. 2 anaerobic reactor is an upflow reactor equipped with a stirrer and a sealed cover.

[0037] According to the present invention, preferably, both reactor No. 1 and reactor No. 2 are filled with packing material.

[0038] Preferably, the filler is polyurethane foam, and preferably, the average porosity of the polyurethane foam is 80% to 95%.

[0039] In this invention, the polyurethane foam used is 1-2 cm in size. 3 .

[0040] A second aspect of the present invention provides a method for the combined enrichment culture of iron autotrophic denitrification coupled with anaerobic ammonia oxidation, comprising the following steps:

[0041] S1, Bacterial Culture Initiation Phase

[0042] Step 1: Add the substances required for iron autotrophic denitrification to the inlet tank, inoculate the first activated sludge into the No. 1 anoxic reactor, start the inlet tank to drain the air in the No. 1 anoxic reactor, add iron powder, and start the cultivation and acclimatization of iron autotrophic denitrification bacteria under anoxic conditions.

[0043] Step 2: The effluent from the No. 1 anoxic reactor enters the intermediate tank, where the substances required for the anaerobic ammonia oxidation reaction are added and mixed thoroughly.

[0044] Step 3: Inoculate the second activated sludge into anaerobic reactor No. 2. The effluent from the intermediate tank enters anaerobic reactor No. 2. Under anoxic or anaerobic conditions, denitrification and enrichment of anaerobic ammonia-oxidizing bacteria are carried out.

[0045] S2, the bacterial enrichment stage

[0046] Step 4: Monitor the concentrations of ammonia nitrogen, nitrite nitrogen, and nitrate nitrogen in the effluent of Anoxic Reactor No. 1. The nitrate removal rate in the effluent of Anoxic Reactor No. 1 is greater than 70%, and ammonia and nitrite appear in the effluent, indicating that the iron autotrophic denitrification has been successfully started. Then, increase the nitrate nitrogen load in the influent of Anoxic Reactor No. 1 and add iron powder.

[0047] Step 5: Monitor the concentrations of ammonia nitrogen, nitrite nitrogen, and nitrate nitrogen in the effluent of anaerobic reactor No. 2. If the total nitrogen removal rate of the effluent from anaerobic reactor No. 2 is greater than 60%, and the removal rates of nitrite nitrogen and ammonia nitrogen are greater than 70%, the anaerobic ammonia-oxidizing bacteria culture has been successfully started. Then, gradually increase the total nitrogen load of the influent to anaerobic reactor No. 2, increasing the total nitrogen content in increments of 50–120 mg / L over a period of 7–14 days, until the removal rates of nitrite nitrogen and ammonia nitrogen reach over 90% and anaerobic reactor No. 2 turns noticeably red, the enrichment is complete.

[0048] According to the present invention, preferably, the total nitrogen content increases in a ratio of 80 to 100 mg / L.

[0049] According to the present invention, preferably, the amount of iron powder added is 8-10g, and the particle size of the iron powder is preferably 150-200 mesh.

[0050] Preferably, the nitrate nitrogen load increases in increments of 60–80 mg / L, and the iron powder replenishment is 3–5 g / 10 days.

[0051] In this invention, to ensure the smooth start-up of the No. 1 anoxic reactor, an excess of iron powder is required. 8-10g is added at startup, followed by 3-5g every ten days based on the remaining iron powder in the reactor. The iron powder settles to the bottom after addition. Stirring generates ferrous iron (Fe2+), which is then oxidized to ferric iron (Fe3+). Ferric iron accumulates in the upper part of the reactor, while ferrous iron mainly accumulates in the middle, where the main reaction occurs. The upflow velocity is controlled at 3-4 m / h.

[0052] 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.

[0053] Preferably, the inoculation concentration of the first activated sludge is 500–800 mg / L.

[0054] Preferably, the inoculation concentration of the second activated sludge is 300–500 mg / L.

[0055] According to the present invention, preferably, the incubation start-up phase of the No. 1 anoxic reactor lasts for 20-40 days.

[0056] According to the present invention, preferably, the cultivation start-up phase of the No. 2 anaerobic reactor lasts for 30-40 days.

[0057] According to the present invention, preferably, the substances required for iron autotrophic denitrification are nitrate nitrogen salt, first inorganic carbon and first micro-liquid, wherein the mass ratio of nitrate nitrogen to first inorganic carbon is 1:1 to 2, and the content of the first micro-liquid is 0.1 to 0.2 wt% based on the total weight of the substances required for iron autotrophic denitrification.

[0058] Preferably, the nitrate nitrogen salt is sodium nitrate; the first inorganic carbon is sodium bicarbonate; and the first micro-liquid contains potassium dihydrogen phosphate, dipotassium hydrogen phosphate, calcium chloride, and magnesium chloride.

[0059] More preferably, the concentration of potassium dihydrogen phosphate is 0.5–1 g / L, the concentration of dipotassium hydrogen phosphate is 1–2 g / L, the concentration of calcium chloride is 0.3–0.5 g / L, and the concentration of magnesium chloride is 0.5–0.8 g / L.

[0060] According to the present invention, preferably, the substances required for the anaerobic ammonia oxidation reaction are ammonia nitrogen salt, nitrite nitrogen salt, second inorganic carbon, other inorganic salts, and a second micro-liquid, wherein the mass ratio of ammonia nitrogen to nitrite nitrogen is 1:0.8 to 1, the mass ratio of total nitrogen to second inorganic carbon is 1:0.5 to 0.8, 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%.

[0061] Preferably, the other inorganic salt is at least one of calcium salt, magnesium salt and iron salt.

[0062] More preferably, the amount of substances added for the anaerobic ammonia oxidation reaction is such that the water entering the inlet tank during the start-up phase has the following concentrations: total nitrogen concentration not exceeding 200 mg / L, calcium ion concentration of 0.1–0.2 g / L, magnesium ion concentration of 0.1–0.2 g / L, and iron ion concentration of 0.05–0.1 g / L.

[0063] 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.

[0064] Preferably, the nitrite is sodium nitrite and / or potassium nitrite, with sodium nitrite being the most preferred.

[0065] Preferably, the second inorganic carbon is a carbonate and / or bicarbonate, more preferably sodium carbonate and / or sodium bicarbonate, and even more preferably sodium bicarbonate.

[0066] Preferably, the calcium salt is calcium chloride.

[0067] Preferably, the magnesium salt is magnesium chloride and / or magnesium sulfate.

[0068] Preferably, the iron salt is ferrous sulfate and / or ferric sulfate.

[0069] According to the present invention, preferably, the second micro-liquid comprises potassium dihydrogen phosphate, cobalt chloride, manganese chloride, copper chloride, zinc chloride, boric acid, EDTA, and (NH4)6Mo7O. 24 ·4H2O, Na2SeO3·6H2O and NiCl2.

[0070] Preferably, the concentrations of potassium dihydrogen phosphate are 25–35 mg / L, cobalt chloride is 0.1–0.2 mg / L, manganese chloride is 0.1–0.2 mg / L, copper chloride is 0.05–0.1 mg / L, zinc chloride is 0.002–0.005 mg / L, boric acid is 0.002–0.005 mg / L, EDTA is 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.

[0071] According to the present invention, preferably, the bacterial concentration in the No. 2 anaerobic reactor is increased to 0.8-1.5 g / L, and the enrichment of anaerobic ammonia oxidizing bacteria is completed.

[0072] According to the present invention, preferably, the volume of the first anoxic reactor is 3-5L, and the control conditions of the first reactor include: pH 6.5-7.2, dissolved oxygen concentration 0.2-0.4mg / L, and temperature 30-35℃.

[0073] According to the present invention, preferably, the volume of the No. 2 anaerobic reactor is 3-5L, and the control conditions of the No. 2 reactor include: pH 7.0-8.2, dissolved oxygen concentration less than 0.1mg / L, and temperature 30-35℃.

[0074] 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.

[0075] 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.

[0076] Example 1

[0077] In this embodiment, the following is adopted: Figure 1 The iron autotrophic denitrification coupled with anaerobic ammonia oxidation enrichment culture device shown is used. The device includes: an inlet tank, an anoxic reactor No. 1, an intermediate tank, and an anaerobic reactor No. 2. The anoxic reactor No. 1 is an upflow reactor equipped with a three-phase separation device and a stirrer. The anaerobic reactor No. 2 is an upflow reactor equipped with a stirrer and a sealed cover. Both the anoxic reactor No. 1 and the anaerobic reactor No. 2 are filled with polyurethane sponge, and the average porosity of the polyurethane sponge is 90%.

[0078] The inlet tank is used for mixing and adjusting the inlet components of the No. 1 anoxic reactor, and it is equipped with an inlet tank outlet pipeline connected to the No. 1 anoxic reactor. The No. 1 anoxic reactor is used for the cultivation and enrichment of iron-autotrophic denitrifying bacteria, and it is equipped with a No. 1 anoxic reactor outlet pipeline connected to the intermediate tank. The intermediate tank is used for mixing and adjusting the inlet components of the No. 2 anaerobic reactor, and it is equipped with an intermediate tank outlet pipeline connected to the No. 2 anaerobic reactor. The No. 2 anaerobic reactor is used for the start-up, cultivation, and enrichment of anaerobic ammonia-oxidizing bacteria, and it is equipped with a No. 2 anaerobic reactor outlet pipeline connected to the No. 1 anoxic reactor. The bottom of the No. 1 anoxic reactor is equipped with a bottom return pipeline, and the No. 2 anaerobic reactor is equipped with a bottom return pipeline. Preferably, pumps are installed on the water outlet pipeline of the inlet tank, the bottom return pipeline of the No. 1 anoxic reactor, the water outlet pipeline of the intermediate tank, the water outlet pipeline of the No. 2 anaerobic reactor, and the bottom return pipeline of the No. 2 anaerobic reactor.

[0079] The iron autotrophic denitrification coupled with anaerobic ammonia oxidation enrichment culture includes the following steps:

[0080] S1, Bacterial Culture Initiation Phase

[0081] Step 1: Add the substances required for iron autotrophic denitrification to the inlet tank, inoculate 800 mg / L activated sludge into the No. 1 anoxic reactor, start the inlet tank to drain the air in the No. 1 anoxic reactor, add 8-10 g of iron powder, and start the cultivation and acclimatization of iron autotrophic denitrification bacteria under anoxic conditions.

[0082] Step 2: The effluent from the No. 1 anoxic reactor enters the intermediate tank, where the substances required for the anaerobic ammonia oxidation reaction are added and mixed thoroughly.

[0083] Step 3: Inoculate 500 mg / L activated sludge into anaerobic reactor No. 2. The effluent from the intermediate tank enters anaerobic reactor No. 2. Under anoxic or anaerobic conditions, denitrification and enrichment of anaerobic ammonia-oxidizing bacteria are carried out.

[0084] During the start-up phase, the nitrate nitrogen concentration in the influent tank is 50 mg / L, and the inorganic carbon concentration is 100 mg / L. The nitrate nitrogen is provided by sodium nitrate, and the inorganic carbon is provided by sodium bicarbonate. The influent micro-liquid consists of 1 g / L potassium dihydrogen phosphate, 2 g / L dipotassium hydrogen phosphate, 1 g / L calcium chloride, and 2 g / L magnesium chloride. The intermediate tank influent concentrations are: ammonia nitrogen 50 mg / L, nitrite nitrogen 40 mg / L, inorganic carbon 45 mg / L, calcium ion concentration 0.1 mg / L, magnesium ion concentration 0.1 mg / L, total phosphorus concentration 0.2 mg / L, and iron ion concentration 0.07 mg / L. The ammonia nitrogen source is ammonium chloride, the nitrite nitrogen source is sodium nitrite, and the inorganic carbon source is sodium bicarbonate. The micro-liquids consist 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)₆Mo₇O₇. 24 ·4H2O 0.005mg / L, Na2SeO3·6H2O0.005mg / L, NiCl2 0.005mg / L.

[0085] The influent flow rate of the No. 1 anoxic reactor was 2 L / day, with 10 g of iron powder added. Iron powder was replenished as needed based on the reactor's condition. The effective reactor volume was 5 L, the hydraulic retention time was 2.5 days, dissolved oxygen was controlled at 0.3 mg / L, the temperature was controlled at 30°C, the pH was 6.9, the stirring rate was 35 rpm, and the upflow velocity was 3.5 m / h. The concentrations of ammonia nitrogen, nitrite nitrogen, and nitrate nitrogen in the effluent were monitored daily.

[0086] The influent flow rate of anaerobic reactor No. 2 is 2L / day, the effective volume of the reactor is 5L, the hydraulic retention time is 2.5 days, the dissolved oxygen is controlled at 0.1mg / L, the temperature is controlled at 35 degrees, the pH is 7.3, and the stirring speed is 100rpm.

[0087] The concentrations of ammonia nitrogen, nitrite nitrogen, and nitrate nitrogen in the effluent were monitored daily. Eight days after the unit was started up, the nitrate nitrogen in the effluent from the No. 1 anoxic reactor was less than 20 mg / L, and the ammonia nitrogen and nitrite nitrogen concentrations in the effluent from the No. 2 anaerobic reactor were less than 1 mg / L. The influent flow rate was gradually increased, and the hydraulic retention time was reduced.

[0088] On the 20th day of startup, the influent flow rate of the No. 1 anoxic reactor was 5L / day, the hydraulic retention time was 24h, the effluent nitrate nitrogen of the No. 1 anoxic reactor was less than 15mg / L, and the effluent ammonia nitrogen and nitrite nitrogen were both less than 1mg / L. The effluent ammonia nitrogen of the No. 2 anaerobic reactor was less than 1mg / L, the nitrite nitrogen concentration was less than 1mg / L, and the total nitrogen removal rate was greater than 80%. Startup was completed.

[0089] S2, the bacterial enrichment stage

[0090] Step 4: Enrichment culture using a gradient increase in total nitrogen concentration. Gradually increase the concentrations of nitrate nitrogen, ammonia nitrogen, nitrite nitrogen, and inorganic carbon in the influent of reactors 1 and 2, while keeping other concentrations constant. The ratio of nitrate nitrogen to inorganic carbon in the influent of anoxic reactor 1 is controlled at 1:1.5, and the ratio of ammonia nitrogen, nitrite nitrogen, and inorganic carbon in the influent of anaerobic reactor 2 is controlled at 1:0.8:0.5. The nitrate nitrogen loading in reactor 1 increases at a rate of 60 mg / L / 7 days, and the total nitrogen loading in reactor 2 increases at a rate of... The concentration of nitrogen was increased by 100 mg / L over 7 days. By day 55, the influent nitrate nitrogen concentration in anoxic reactor No. 1 was 300 mg / L, the effluent nitrate nitrogen concentration was 85 mg / L, and the nitrite nitrogen and ammonia nitrogen concentrations were both less than 10 mg / L. In anaerobic reactor No. 2, the influent ammonia nitrogen concentration was 300 mg / L, the nitrite nitrogen concentration was 240 mg / L, the total nitrogen concentration was 540 mg / L, and the effluent total nitrogen concentration was 53.6 mg / L, achieving a removal rate of 90.07%. The sludge in the reactors turned noticeably red, indicating that enrichment was complete.

[0091] Example 2

[0092] In this embodiment, the iron autotrophic denitrification coupled with anaerobic ammonium oxidation co-enrichment culture device and the iron autotrophic denitrification coupled with anaerobic ammonium oxidation co-enrichment culture method are the same as in Example 1. The difference is that during the start-up phase, the nitrate nitrogen concentration in the influent tank is 100 mg / L, and the inorganic carbon concentration is 150 mg / L. The substance providing nitrate nitrogen is sodium nitrate, and the substance providing inorganic carbon is sodium bicarbonate. The influent micro-liquid 2 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 The concentrations of 4H₂O, Na₂SeO₃·6H₂O, and NiCl₂ are 0.005 mg / L. The intermediate tank influent concentrations are: ammonia nitrogen 100 mg / L, nitrite nitrogen 80 mg / L, inorganic carbon 90 mg / L, calcium ion concentration 0.2 mg / L, magnesium ion concentration 0.2 mg / L, total phosphorus concentration 0.4 mg / L, and iron ion concentration 0.14 mg / L. The ammonia nitrogen is provided by ammonium chloride, the nitrite nitrogen by sodium nitrite, and the inorganic carbon by sodium bicarbonate. The micro-liquid concentrations are the same as those in the influent tank.

[0093] Start the influent flow rate at 1L / day, adding 8g of iron powder, with subsequent iron powder replenishment as needed based on reactor conditions. The reactor has an effective volume of 5L, a hydraulic retention time of 5 days, dissolved oxygen controlled at 0.2mg / L, temperature controlled at 30°C, pH at 7, stirring speed at 80rpm, and upflow velocity at 3m / h. Monitor the concentrations of ammonia nitrogen, nitrite nitrogen, and nitrate nitrogen in the effluent daily.

[0094] The influent flow rate of anaerobic reactor No. 2 is 1L / day, the effective reactor volume is 5L, the hydraulic retention time is 5 days, the dissolved oxygen is controlled at 0.1mg / L, the temperature is controlled at 35 degrees Celsius, the pH is 7, and the stirring rate is 30rpm. The concentrations of ammonia nitrogen, nitrite nitrogen, and nitrate nitrogen in the effluent are measured daily.

[0095] Three days after startup, the nitrate nitrogen in the effluent from reactor 1 was less than 20 mg / L, and the ammonia nitrogen and nitrite nitrogen concentrations in the effluent from anaerobic reactor 2 were less than 1 mg / L and 1 mg / L, respectively. The influent flow rate was gradually increased while the hydraulic retention time was decreased. On the 25th day of startup, the influent flow rate to both reactors was 5 L / day, and the hydraulic retention time was 24 h. The nitrate nitrogen in the effluent from anoxic reactor 1 was less than 30 mg / L, and both ammonia nitrogen and nitrite nitrogen were less than 1 mg / L. The ammonia nitrogen and nitrite nitrogen concentrations in the effluent from anaerobic reactor 2 were less than 10 mg / L, respectively. The total nitrogen removal rate was greater than 80%, indicating successful startup.

[0096] Enrichment culture was conducted using a gradient increase in total nitrogen concentration. The concentrations of nitrate nitrogen, ammonia nitrogen, nitrite nitrogen, and inorganic carbon in the influent of reactors 1 and 2 were gradually increased in a gradient manner, with the concentration gradient being the same as in Example 1, and other concentrations remaining unchanged. Specifically, the ratio of nitrate nitrogen to inorganic carbon in the influent of anoxic reactor 1 was controlled at 1:1.5, and the ratio of ammonia nitrogen, nitrite nitrogen, and inorganic carbon in the influent of anaerobic reactor 2 was controlled at 1:0.8:0.5. By day 58, the influent nitrate nitrogen in anoxic reactor 1 was 300 mg / L, and the effluent nitrate nitrogen was 80 mg / L, while nitrite nitrogen and ammonia nitrogen were both less than 10 mg / L. In anaerobic reactor 2, the influent ammonia nitrogen was 300 mg / L, nitrite nitrogen was 240 mg / L, the total nitrogen concentration was 540 mg / L, and the effluent total nitrogen was 48.2 mg / L, achieving a removal rate of 91%. The sludge in the reactors turned noticeably red, indicating that enrichment was complete.

[0097] Example 3

[0098] The only difference between this embodiment and Example 1 is that, during the bacterial enrichment phase, nitrate nitrogen was increased at a rate of 50 mg / L / 10 days, and total nitrogen was increased at a rate of 100 mg / L / 10 days.

[0099] On the 70th day after startup, the influent nitrate nitrogen in the No. 1 anoxic reactor was 300 mg / L, the effluent nitrate nitrogen was 76 mg / L, and both nitrite nitrogen and ammonia nitrogen were less than 10 mg / L. In the No. 2 anaerobic reactor, the influent ammonia nitrogen was 300 mg / L, nitrite nitrogen was 250 mg / L, the total nitrogen concentration was 550 mg / L, and the effluent total nitrogen was 40.3 mg / L, with a removal rate of 92.6%. The sludge in the reactors turned noticeably red, indicating that enrichment was complete.

[0100] Example 4

[0101] The only difference between this embodiment and Example 1 is that during the bacterial enrichment phase, the total nitrogen content is increased at a rate of 150 mg / L / 7 days.

[0102] On the 50th day of operation, the influent nitrate nitrogen in the No. 1 anoxic reactor was 300 mg / L, the effluent nitrate nitrogen was 85 mg / L, and both nitrite nitrogen and ammonia nitrogen were less than 10 mg / L. In the No. 2 anaerobic reactor, the influent ammonia nitrogen was 300 mg / L, nitrite nitrogen was 240 mg / L, the total nitrogen concentration was 540 mg / L, and the effluent total nitrogen was 88.9 mg / L, with a removal rate of 83.5%. The excessive total nitrogen had an inhibitory effect and failed to achieve the predetermined removal rate.

[0103] 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.

[0104] 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 combined enrichment and cultivation device for iron autotrophic denitrification coupled with anaerobic ammonium oxidation, characterized in that, include: Inlet tank, No. 1 anoxic reactor, intermediate tank and No. 2 anaerobic reactor; The inlet tank is used for mixing and adjusting the inlet components of the No. 1 anoxic reactor. It is equipped with an outlet pipeline, which is connected to the No. 1 anoxic reactor. The No. 1 anoxic reactor is used for the cultivation and enrichment of iron-autotrophic denitrifying bacteria. It is equipped with an outlet pipeline of the No. 1 anoxic reactor, which is connected to the intermediate tank. The intermediate tank is used for mixing and adjusting the influent components of anaerobic reactor No.

2. It is equipped with an intermediate tank outlet pipeline, which is connected to anaerobic reactor No.

2. The No. 2 anaerobic reactor is used for the start-up, cultivation, and enrichment of anaerobic ammonia-oxidizing bacteria. It is equipped with a No. 2 anaerobic reactor effluent pipeline, which is connected to the No. 1 anoxic reactor.

2. The iron autotrophic denitrification coupled with anaerobic ammonium oxidation co-enrichment culture device according to claim 1, wherein, The bottom of the No. 1 anoxic reactor is equipped with a bottom return pipeline, and the bottom of the No. 2 anaerobic reactor is equipped with a bottom return pipeline.

3. The iron autotrophic denitrification coupled with anaerobic ammonium oxidation co-enrichment culture device according to claim 2, wherein, Pumps are installed on the inlet tank outlet pipeline, the bottom return pipeline of No. 1 anoxic reactor, the intermediate tank outlet pipeline, the outlet pipeline of No. 2 anaerobic reactor, and the bottom return pipeline of No. 2 anaerobic reactor.

4. The iron autotrophic denitrification coupled with anaerobic ammonium oxidation co-enrichment culture device according to claim 1, wherein, The No. 1 anoxic reactor is an upflow reactor equipped with a three-phase separation device and a stirrer; The No. 2 anaerobic reactor is an upflow reactor equipped with a stirrer and a sealed cover.

5. The iron autotrophic denitrification coupled with anaerobic ammonium oxidation combined enrichment culture device according to claim 1, wherein, Both the No. 1 anoxic reactor and the No. 2 anaerobic reactor were filled with packing material.

6. The iron autotrophic denitrification coupled with anaerobic ammonium oxidation co-enrichment culture device according to claim 5, wherein, The filler is polyurethane foam.

7. The iron autotrophic denitrification coupled with anaerobic ammonium oxidation co-enrichment culture device according to claim 6, wherein, The average porosity of the polyurethane foam is 80%~95%.

8. A method for enriching iron autotrophic denitrification coupled with anaerobic ammonium oxidation, characterized in that, This method is carried out using the iron autotrophic denitrification coupled with anaerobic ammonium oxidation combined enrichment culture device as described in any one of claims 1-7, and includes the following steps: S1, Bacterial Culture Initiation Phase Step 1: Add the substances required for iron autotrophic denitrification to the inlet tank, inoculate the first activated sludge into the No. 1 anoxic reactor, start the inlet tank to drain the air in the No. 1 anoxic reactor, add iron powder, and start the cultivation and acclimatization of iron autotrophic denitrification bacteria under anoxic conditions. Step 2: The effluent from the No. 1 anoxic reactor enters the intermediate tank, where the substances required for the anaerobic ammonia oxidation reaction are added and mixed thoroughly. Step 3: Inoculate the second activated sludge into anaerobic reactor No.

2. The effluent from the intermediate tank enters anaerobic reactor No.

2. Under anoxic or anaerobic conditions, denitrification and enrichment of anaerobic ammonia-oxidizing bacteria are carried out. S2, the bacterial enrichment stage Step 4: Monitor the concentrations of ammonia nitrogen, nitrite nitrogen, and nitrate nitrogen in the effluent of Anoxic Reactor No.

1. The nitrate removal rate in the effluent of Anoxic Reactor No. 1 is greater than 70%, and ammonia and nitrite appear in the effluent, indicating that the iron autotrophic denitrification has been successfully started. Then, increase the nitrate nitrogen load in the influent of Anoxic Reactor No. 1 and add iron powder. Step 5: Monitor the concentrations of ammonia nitrogen, nitrite nitrogen, and nitrate nitrogen in the effluent of anaerobic reactor No.

2. If the total nitrogen removal rate of the effluent from anaerobic reactor No. 2 is greater than 60%, and the removal rates of nitrite nitrogen and ammonia nitrogen are greater than 70%, the anaerobic ammonia-oxidizing bacteria culture has been successfully started. Then, gradually increase the total nitrogen load of the influent to anaerobic reactor No. 2, increasing the total nitrogen 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. 2 turns noticeably red, the enrichment is complete.

9. The method for combined enrichment culture of iron autotrophic denitrification coupled with anaerobic ammonium oxidation according to claim 8, wherein, The total nitrogen content was increased in increments of 80–100 mg / L.

10. The iron autotrophic denitrification coupled with anaerobic ammonia oxidation enrichment culture method according to claim 8, wherein, The amount of iron powder added is 8-10g; The nitrate nitrogen load is increased in increments of 50–80 mg / L, and the iron powder supplementation is 3–5 g / 10 days.

11. The iron autotrophic denitrification coupled with anaerobic ammonium oxidation enrichment culture method according to claim 10, wherein, The iron powder has a particle size of 150-200 mesh.

12. The iron autotrophic denitrification coupled with anaerobic ammonia oxidation enrichment culture method according to claim 8, 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 500–800 mg / L; The inoculation concentration of the second activated sludge is 300–500 mg / L.

13. The iron autotrophic denitrification coupled with anaerobic ammonium oxidation enrichment culture method according to claim 8, wherein, The incubation start-up phase of the No. 1 anoxic reactor lasts for 20-40 days. The incubation and start-up phase of the No. 2 anaerobic reactor takes 30-40 days.

14. The iron autotrophic denitrification coupled with anaerobic ammonium oxidation enrichment culture method according to claim 8, wherein, The substances required for iron autotrophic denitrification are nitrate, first inorganic carbon and first micro-liquid, wherein the mass ratio of nitrate nitrogen to first inorganic carbon is 1:1 to 2, and the content of the first micro-liquid is 0.1 to 0.2 wt% based on the total weight of the substances required for iron autotrophic denitrification.

15. The iron autotrophic denitrification coupled with anaerobic ammonia oxidation enrichment culture method according to claim 14, wherein, The nitrate is sodium nitrate; the first inorganic carbon is sodium bicarbonate; the first micro-liquid contains potassium dihydrogen phosphate, dipotassium hydrogen phosphate, calcium chloride, and magnesium chloride.

16. The iron autotrophic denitrification coupled with anaerobic ammonia oxidation enrichment culture method according to claim 15, wherein, The concentration of potassium dihydrogen phosphate is 0.5–1 g / L, the concentration of dipotassium hydrogen phosphate is 1–2 g / L, the concentration of calcium chloride is 0.3–0.5 g / L, and the concentration of magnesium chloride is 0.5–0.8 g / L.

17. The method for combined enrichment culture of iron autotrophic denitrification coupled with anaerobic ammonium oxidation according to claim 8, wherein, The substances required for the anaerobic ammonia oxidation reaction are ammonium salt, nitrite, second inorganic carbon, other inorganic salts, and second micro-liquid. The mass ratio of ammonia nitrogen to nitrite nitrogen is 1:0.8-1, the mass ratio of total nitrogen to second inorganic carbon is 1:0.5-0.8, the content of other inorganic salts is 1-5 wt%, and the content of micro-liquid is 0.1-0.2 wt%.

18. The iron autotrophic denitrification coupled with anaerobic ammonium oxidation enrichment culture method according to claim 17, wherein, The other inorganic salts are at least one of calcium salts, magnesium salts, and iron salts.

19. The iron autotrophic denitrification coupled with anaerobic ammonium oxidation enrichment culture method according to claim 18, 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 ion 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.

20. The iron autotrophic denitrification coupled with anaerobic ammonium oxidation enrichment culture method according to claim 18, 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 second inorganic carbon is a carbonate and / or 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.

21. The iron autotrophic denitrification coupled with anaerobic ammonium oxidation enrichment culture method according to claim 20, wherein, The ammonium salt is ammonium chloride.

22. The iron autotrophic denitrification coupled with anaerobic ammonium oxidation enrichment culture method according to claim 20, wherein, The nitrite is sodium nitrite.

23. The iron autotrophic denitrification coupled with anaerobic ammonium oxidation enrichment culture method according to claim 20, wherein, The second inorganic carbon is sodium carbonate and / or sodium bicarbonate.

24. The iron autotrophic denitrification coupled with anaerobic ammonium oxidation enrichment culture method according to claim 23, wherein, The second inorganic carbon is sodium bicarbonate.

25. The iron autotrophic denitrification coupled with anaerobic ammonium oxidation enrichment culture method according to claim 17, wherein, The second micro-liquid contains potassium dihydrogen phosphate, cobalt chloride, manganese chloride, copper chloride, zinc chloride, boric acid, EDTA, and (NH4)6Mo7O. 24 ·4H2O, Na2SeO3·6H2O and NiCl2.

26. The iron autotrophic denitrification coupled with anaerobic ammonium oxidation enrichment culture method according to claim 25, wherein, The concentrations of potassium dihydrogen phosphate (25–35 mg / L), cobalt chloride (0.1–0.2 mg / L), manganese chloride (0.1–0.2 mg / L), copper chloride (0.05–0.1 mg / L), zinc chloride (0.002–0.005 mg / L), boric acid (0.002–0.005 mg / L), EDTA (0.05–0.1 mg / L), and (NH₄)₆Mo₇O₇ 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.

27. The iron autotrophic denitrification coupled with anaerobic ammonium oxidation enrichment culture method according to claim 8, wherein, The bacterial concentration in the No. 2 anaerobic reactor increased to 0.8~1.5g / L, and the enrichment of anaerobic ammonia oxidizing bacteria was completed.

28. The iron autotrophic denitrification coupled with anaerobic ammonium oxidation enrichment culture method according to claim 8, wherein, The volume of the No. 1 anoxic reactor is 3-5L. The control conditions of the No. 1 anoxic reactor include: pH 6.5-7.2, dissolved oxygen concentration 0.2-0.4mg / L, and temperature 30-35℃. The volume of the No. 2 anaerobic reactor is 3-5L. The control conditions for the No. 2 anaerobic reactor include: pH 7.0-8.2, dissolved oxygen concentration less than 0.1mg / L, and temperature 30-35℃.

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