Method for synchronously culturing ammonia oxidizing bacteria and nitrite oxidizing bacteria

Abstract

The invention relates to the technical field of wastewater treatment or water quality purification, in particular to a method for synchronously culturing ammonia oxidizing bacteria and nitrite oxidizing bacteria, which comprises the following steps: selecting an inorganic material which is large in specific surface area and can quickly neutralize and release alkalinity as a nitrifying bacteria attachment carrier and an alkalinity supplement / pH regulator; the carrier is dissolved through nitration acid production, carbon dioxide and alkalinity are released, a carbon source and alkalinity required by growth are provided for nitrifying bacteria, and propagation of the nitrifying bacteria is promoted. Ammonia oxidizing bacteria and nitrite oxidizing bacteria are cultured synchronously by controlling the growth speed of the two bacteria in the culture process. By controlling the ammonia nitrogen concentration and nitrite concentration of the effluent at the end of culture to be lower than 50mg / L, sufficient time is provided for nitrite oxidizing bacteria to decompose an intermediate product nitrite, so that the purpose of simultaneously culturing AOB and NOB is achieved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of wastewater treatment or water purification, in particular to a method for high-density synchronous fermentation culture of ammonia-oxidizing bacteria and nitrite-oxidizing bacteria, and an integrated nitrification material and its applications in preparation of nitrifying bacteria culture, sludge nitrification synergism, etc. BACKGROUND

[0002] Nitrifying bacteria are a class of chemoautotrophic bacteria with nitrification function, including ammonia-oxidizing bacteria (AOB) and nitrite-oxidizing bacteria (NOB) two physiological bacterial groups. Nitrifying bacteria have a long reproductive cycle, usually with a metabolic time of 24-48 hours. The content of nitrifying bacteria in the activated sludge of common wastewater treatment systems is relatively low, but they play a crucial role in the denitrification process. Without nitrifying bacteria, ammonia nitrogen cannot be converted into nitrate in the denitrification process. Therefore, the nitrification capacity is directly related to whether the municipal wastewater treatment plant can operate normally and whether the effluent can meet the standards. After the nitrification function of the wastewater treatment system collapses, new nitrifying bacteria need to be added to rebuild the ammonia-nitrogen nitrification function of the system. In addition, when the air temperature is low and the wastewater treatment system is started, new nitrifying bacteria also need to be added. Nitrifying bacteria can usually be obtained by activated sludge enrichment and culture method. The content of heavy metals and refractory organic matter in activated sludge is usually high, which can easily introduce new pollution into the wastewater treatment system. The mixed culture of multiple nitrate bacteria and nitrite bacteria has no such disadvantages, and the impact resistance of the mixed culture is not inferior to that of activated sludge. In addition, the culture obtained by the culture method has high purity, high concentration, short culture period, and can achieve high-density culture of nitrifying bacteria in a short time. The culture has strong specificity to pollutants, and the target pollutant can be used as the only nitrogen source during the expansion culture. After repeated screening and domestication, the culture can achieve the purpose of high-efficiency degradation of the target pollutant. Therefore, the culture and enrichment technology of nitrifying bacteria has gradually become a research hotspot in the direction of water treatment and aquaculture, and is very important. Nitrifying bacteria are usually attached-growth microorganisms. In the culture process, the maximum concentration of nitrifying bacteria culture is usually not high due to the limitation of the inner surface of the culture container and mass transfer.

[0003] Currently, the patents on ammonia-oxidizing bacteria and nitrite-oxidizing bacteria at home and abroad mainly include mixed enrichment culture of nitrifying bacteria and separate pure fermentation culture of ammonia-oxidizing bacteria or nitrite-oxidizing bacteria. For example, Japanese patent JP2001-503616 proposes using a mixture of sodium carbonate and sodium bicarbonate in a certain proportion as an alkalinity supplement and pH regulator, which can to some extent solve the problem of inhibition of nitrifying bacteria growth caused by high pH of sodium carbonate. However, due to the lack of carriers, when the concentration of ammonia nitrogen is higher than 300 mg / L, seawater or freshwater needs to be used for appropriate dilution.

[0004] As the domestic patent "a method for culturing nitrifying bacteria (CN201410263301.3)" proposes to use straw powder, sawdust powder, corn cob powder, polycaprolactone and other degradable fibers as nitrifying bacteria culture carrier, and to culture nitrifying bacteria by intermittent aeration. This method can improve the concentration of nitrifying bacteria and shorten the batch culture time. However, the culture medium uses 0.5-2.0g / L of ammonium sulfate, and the complete consumption of ammonia nitrogen requires 5d. The ammonia nitrogen concentration in the culture medium is 100-420mg / L, and this method is only suitable for ammonia-oxidizing bacteria culture, not for simultaneous culture of ammonia-oxidizing bacteria and nitrite-oxidizing bacteria.

[0005] The domestic patent "a microcarrier for improving the culture density of nitrifying bacteria and its preparation method (CN201811177583.X)" discloses a calcium carbonate and basic magnesium carbonate mixed crystal microcarrier prepared by using Na2CO3 solution, CaCl2 solution and MgCl2 solution and sodium polyacrylate, which is used to improve the culture density of nitrifying bacteria and can increase the ammonia oxidation rate of nitrifying bacteria by 2-3 times, slightly better than the culture activity of using calcium carbonate and basic magnesium carbonate as carrier alone. However, the preparation process of this mixed crystal microcarrier is complex, not suitable for large-scale culture of nitrifying bacteria, and also not suitable for culture of nitrifying bacteria with high ammonia nitrogen concentration medium.

[0006] The domestic patent "a method for rapidly and massively enriching nitrifying bacteria and its application (CN201710385505.8)" discloses a method for enriching nitrifying bacteria by adding fly ash as filler in SBR reactor and continuously increasing the ammonia nitrogen concentration in the influent, and adjusting pH with 1mol / L sodium bicarbonate. This method can increase the influent ammonia nitrogen to 1000-1200mg / L. However, since fly ash itself does not have the function of buffering acidic pH and providing inorganic carbon source, a large amount of sodium bicarbonate must be used for adjustment. Due to the weak pH buffering capacity of sodium bicarbonate, the consumption is large. At the same time, this method is only suitable for enriching Nitrosomonas, i.e. ammonia-oxidizing bacteria, not for simultaneously enriching nitrite-oxidizing bacteria, which will discharge a large amount of wastewater containing nitrite, thereby polluting the environment.

[0007] Therefore, at present, there is still a lack of efficient and economical autotrophic nitrifying bacteria fermentation technology, and the ammonia nitrogen concentration in the current culture medium is low, resulting in a large amount of wastewater discharged after fermentation, which cannot be recycled. SUMMARY

[0008] Through the deep study of the growth characteristics of nitrifying bacteria, the applicant found that nitrifying bacteria are more suitable for cultivation in the form of carrier attachment and film formation. In the traditional cultivation process, the carrier and neutralizing agent are added to the cultivation system as two different materials. By using sodium carbonate, sodium bicarbonate or a mixture of the two as an alkalinity supplement, the pH drop during nitrification is prevented. The addition of soluble sodium carbonate or sodium bicarbonate can quickly supplement the alkalinity required for nitrification, and then due to complete dissolution in water, the salt content in the medium after addition is greatly increased, and the alkalinity of sodium carbonate is strong, which often leads to an increase in the pH of the medium. After the addition of ammonium salt, a large amount of free ammonia is produced, which is toxic to ammonia-oxidizing bacteria (AOB) and nitrite-oxidizing bacteria (NOB), and inhibits their growth. Common nitrifying bacteria carriers such as powdered activated carbon, fly ash, polyvinyl alcohol beads, corn cob powder, MBBR filler and other microcarriers can provide nitrifying bacteria with attachment points and large specific surface area, which is beneficial to the attachment of nitrifying bacteria and can greatly improve the nitrification rate and the reproduction rate of nitrifying bacteria. Then, due to the fact that the attached carrier and the alkalinity supplement are two different forms of substances, nitrifying bacteria are easily inhibited by toxic substances in the medium, and the nitrification rate is always difficult to exceed 30 mg NH3-N / Lh. Although some documents have proposed using calcium carbonate or basic magnesium carbonate as a nitrification carrier, due to the unsatisfactory material shape, properties and other factors, it has not been fully explored.

[0009] Based on this, we propose to use the same specific surface area of inorganic materials for nitrifying bacteria attachment carrier and alkalinity supplement / pH regulator, which can quickly neutralize and release alkalinity. Nitrifying bacteria attach to the carrier at the same time, and through nitrification to produce acid and dissolve the carrier, release carbon dioxide and alkalinity, provide carbon source and alkalinity for nitrifying bacteria growth, and promote nitrifying bacteria reproduction. By controlling the growth rate of both during cultivation, ammonia-oxidizing bacteria and nitrite-oxidizing bacteria can be cultured synchronously. By controlling the ammonia nitrogen concentration and nitrite concentration of the effluent at the end of cultivation to be lower than 50 mg / L, sufficient time is given to nitrite-oxidizing bacteria to decompose the intermediate product nitrite, achieving the purpose of simultaneous cultivation of AOB and NOB.

[0010] In view of the problems that the carrier and alkalinity supplement cannot be the same in the existing ammonia-oxidizing bacteria and nitrite-oxidizing bacteria cultivation process, and the high preparation cost, the present application provides a method for synchronous cultivation of ammonia-oxidizing bacteria and nitrite-oxidizing bacteria, characterized in that: water magnesite powder, water magnesite powder, ultra-fine calcium carbonate or a mixture of two or more thereof is used as the main component of the pH neutralizer, inorganic carbon source and growth attachment carrier integrated material for nitrifying bacteria cultivation; the mass ratio of ammonia nitrogen to the pH neutralizer, inorganic carbon source and growth attachment carrier integrated material for nitrifying bacteria cultivation is 1:2-1:15; the medium is placed in a reactor, and a high-density active ammonia-oxidizing bacteria and nitrite-oxidizing bacteria consortium is cultivated.

[0011] Further, the nitrobacteria culture carrier and inorganic carbon source, pH neutralizer integrated material includes at least 30% of water magnesium powder, and further includes more than 70% of water magnesium powder, and further includes more than 90% of water magnesium component or 100% of water magnesium component. The water magnesium belongs to natural basic magnesium carbonate, has flaky porous structure, and is completely different from common synthetic basic magnesium carbonate or light magnesium carbonate. The conventional basic magnesium carbonate has spherical structure, is not conducive to the adhesion of nitrobacteria, and has high pH (generally higher than 8.5) in aqueous solution, so that the pH of the system is high after being added, and the growth of nitrobacteria is inhibited. The alkalinity and release activity of the water magnesium powder in aqueous solution are between heavy magnesium carbonate (magnesite) and light magnesium carbonate (synthetic basic magnesium carbonate), the pH of the aqueous solution is about 7.5-8.0, and the water magnesium powder has quick reaction activity to weak acid and is suitable for being used as a weak acid solution buffer.

[0012] The chemical main components of the water magnesium are xMgCO3·yMg(OH)2·zH2O, wherein the value of x is 3 or 4, the value of y is 1, and the value of z is 3 or 4. The water magnesium is a kind of rare natural hydrated basic magnesium carbonate in the world, commonly known as “magnesium white”. The water magnesium has white block appearance, earthy luster, a density of 2.24 g·cm-3, a Mohs hardness of 3.5, a melting point of 730 DEG C, a monoclinic crystal structure, and flaky porous structure under a microscope. By using all water magnesium or mixing part of superfine light calcium carbonate as the nitrobacteria carrier, the alkalinity supplement and the inorganic carbon source, the alkalinity and carbon dioxide generated by the self-dissolution of the integrated material in the nitration process, and the divalent magnesium ions and calcium ions generated by the acid dissolution, the toxicity of sodium ions generated by the addition of sodium carbonate in the past is lower.

[0013] The ammonia-oxidizing bacteria are selected from bacteria of the Nitrosomonadaceae family, which includes the Nitrosomonas genus, the Nitrosospira genus and the Nitrosovibrio genus. The nitrite-oxidizing bacteria are selected from the Nitrobacter genus and the Nitrospira genus. The ammonia-oxidizing bacteria and the nitrite-oxidizing bacteria can be artificially separated pure bacteria or mixed cultures containing the functional bacteria obtained from nature. The mixed culture refers to an autotrophic ammonia-oxidizing bacteria and nitrite-oxidizing bacteria culture that is long-term domesticated and cultured by adding ammonia nitrogen or nitrite without adding other organic matters. The added ammonia nitrogen is first oxidized into nitrite by the ammonia-oxidizing bacteria (AOB), and the nitrite is then oxidized into nitrate by the NOB bacteria, so as to complete the entire nitrification process.

[0014] In the high-density nitrifying bacteria cultivation method, the mass ratio of the ammonia nitrogen (in terms of N) to the pH neutralizer, inorganic carbon source, and growth-attached carrier integrated material in the culture medium is 1:2-1:15, and further, the mass ratio is 1:3-1:10. The carrier can be added at one time or in batches, or be continuously added by being mixed in the influent in advance. During the cultivation, the pH is maintained in the range of 6.5-9.0.

[0015] The cultivation is carried out in a reactor with aeration and temperature control, which can be a sequencing batch or continuous influent feeding. When the sequencing batch fermentation is used, the ammonium salt or inorganic carrier (alkalinity agent) can be added at one time or in batches, and can be separated by standing or standing and precipitating after adding a flocculating agent, and the nitrifying bacteria culture is retained. When the continuous influent is used, the powder culture solution containing ammonia nitrogen and integrated material can be prepared in proportion, and then the culture solution is continuously added to the cultivation device. The culture can be separated by gravity sedimentation tank or microfiltration membrane, ultrafiltration membrane, etc. to separate the sludge and water, and the flocculent nitrifying bacteria colony is retained.

[0016] In the high-concentration ammonium oxidizing bacteria and nitrite bacteria combined cultivation method, the ammonia nitrogen (in terms of N) concentration in the culture medium is controlled in the range of 500-4000 mg / L. Further, the ammonia nitrogen concentration in the culture medium is 1500-3500 mg / L. The ammonia nitrogen can be provided by using ammonium chloride, ammonium sulfate, ammonium bicarbonate, ammonium nitrate, ammonium carbonate, or a mixture of two or more thereof. When the raw material with alkaline tendency and capable of providing alkalinity such as ammonium bicarbonate and ammonium carbonate is selected as the source of ammonium, the amount of carbonate added can be appropriately adjusted, and the alkalinity neutralizer can be supplemented in multiple times. The pH during the entire reaction process is maintained to be not higher than 10.0, otherwise the nitrifying bacteria metabolism will be inhibited.

[0017] The nitrate nitrogen (in terms of N) concentration in the effluent after the cultivation or in the continuous cultivation is controlled in the range of 800-6500 mg / L. Further, when the ammonia nitrogen concentration in the culture medium is controlled in the range of 2000-3600 mg / L, the nitrification rate is higher. By supplementing sufficient neutralizer, inorganic carbon source, and growth-attached carrier integrated material, the purpose of being consumed in 2 days can be achieved.

[0018] The high-density synchronous fermentation method for culturing ammonia-oxidizing bacteria and nitrite-oxidizing bacteria, when the supernatant of the active ammonia-oxidizing bacteria and nitrite-oxidizing bacteria aggregate is turbid or the settling speed is slow, coagulation is carried out by using iron salt coagulant and polyacrylamide. The iron salt can be selected from one or more than two kinds of mixture of polymeric ferric sulfate, polymeric ferric chloride, polymeric ferric silicate, ferric chloride, and ferric sulfate. The addition amount of the iron salt coagulant is 20-200 mg / L, and the addition amount of the polyacrylamide is 5-50 mg / L. Due to the long-time aeration and the incompleteness of consumption, the supernatant after precipitation has a high suspension, and the iron salt coagulant and polyacrylamide coagulant aid can be used to strengthen the flocculation and sedimentation. At the same time, the addition of iron salt can improve the electron transfer efficiency in the nitrobacteria aggregate, improve the nitrification rate and the toxicity resistance.

[0019] The dissolved oxygen concentration in the culture process is controlled to be 2.0-6.0 mg / L, the temperature is 20-37°C, the pH is in the range of 7.0-9.0, the ammonia nitrogen volumetric load is 0.25-2.5 kgNH3-N / m 3 d. In the culture process, the ammonia nitrogen volumetric load is gradually increased, and it is recommended to increase the ammonia nitrogen volumetric load by 0.05-0.25 kgNH3-N / m 3 d. Preferably, the ammonia nitrogen load is increased by 0.08-0.15 kgNH3-N / m 3 .

[0020] The high-density synchronous fermentation method for culturing ammonia-oxidizing bacteria and nitrite-oxidizing bacteria, when the supernatant of the active ammonia-oxidizing bacteria and nitrite-oxidizing bacteria aggregate is turbid or the settling speed is slow, coagulation is carried out by using iron salt coagulant and polyacrylamide. The iron salt can be selected from one or more than two kinds of mixture of polymeric ferric sulfate, polymeric ferric chloride, polymeric ferric silicate, ferric chloride, and ferric sulfate. The addition amount of the iron salt coagulant is 20-200 mg / L, and the addition amount of the polyacrylamide is 5-50 mg / L. Due to the long-time aeration and the incompleteness of consumption, the supernatant after precipitation has a high suspension, and the iron salt coagulant and polyacrylamide coagulant aid can be used to strengthen the flocculation and sedimentation. At the same time, the addition of iron salt can improve the electron transfer efficiency in the nitrobacteria aggregate, improve the nitrification rate and the toxicity resistance.

[0021] The method for high-density synchronous fermentation culture of ammonia-oxidizing bacteria and nitrite-oxidizing bacteria, and the nitrifying bacteria aggregate after culture, have an ammonium oxidation activity of 30-120 mgNH3-N / Lh and a nitrite oxidation rate of 20-120 mgNO2-N / Lh. The culture is concentrated by gravity, centrifugation, membrane concentration, etc., to obtain a commercial nitrifying bacteria agent with an ammonium oxidation activity of more than 200 mgNH3-N / Lh and a nitrite oxidation rate of more than 150 mgNO2-N / Lh. Since the nitrifying bacteria belong to the attached film growth, a good floc can be formed during the culture process, and the nitrifying bacteria can be separated by simple gravity sedimentation. The floc after culture can also be concentrated conveniently. Generally, the sludge age of the culture is controlled to be 10-20 d, that is, part of the culture is discharged every day to harvest the nitrifying bacteria. Or after reaching the predetermined nitrification activity, most of the nitrifying bacteria are harvested as products, and a part is left as inoculum for re-culture.

[0022] The disclosed technical solution and culture method of the present application have the following advantages over the prior art:

[0023] (1) Simple operation and low preparation cost: the slightly soluble hydromagnesite powder, synthetic hydromagnesite, and ultra-fine light calcium carbonate are used as the carrier and inorganic carbon source, and the pH neutralizer is integrated into one material. The inert carrier, sodium carbonate, and sodium bicarbonate in the conventional nitrifying bacteria culture process are unified into one acid-soluble carbonate inorganic material, which simplifies the frequent addition of various reagents in the nitrifying bacteria culture process, avoids the inhibition of nitrification caused by the pH rise due to excessive addition of conventional sodium carbonate, and avoids the problem of weak pH adjustment ability and fast consumption of sodium bicarbonate. Therefore, the method provided by the present application is simple to operate, easy to control, and easy to realize industrial operation.

[0024] (2) High activity of the cultured nitrifying bacteria: by attaching the nitrifying bacteria to the surface of the hydromagnesite and light calcium carbonate material which can provide alkalinity and inorganic carbon source, the ammonia-oxidizing bacteria (AOB) rapidly utilize ammonia nitrogen while producing a large amount of hydrogen ions, which rapidly neutralize the active carbonate of the adjacent hydromagnesite and light calcium carbonate to produce carbon dioxide and neutralize the hydrogen in the wastewater, preventing the pH from falling. Since the nitrifying bacteria are in close contact with the carrier, they have a faster neutralization speed for the generated acid. By using natural hydromagnesite and synthetic hydromagnesite as the carrier and inorganic carbon source, and the pH neutralizer as the same functional material, a synergistic effect is produced, and the nitrifying bacteria culture speed and metabolic efficiency are significantly higher than those of the conventional nitrifying bacteria culture method using inert carriers and only calcium carbonate and magnesium carbonate as neutralizers. After domestication and stable culture, the ammonia oxidation activity is usually 30-120 mgNH3-N / Lh, and the nitrite oxidation rate is 20-120 mgNO2-N / Lh, which is much higher than the activity of the nitrifying bacteria cultured by the conventional inert carrier.

[0025] Further, the present application also has the following advantages

[0026] (1) High ammonia nitrogen concentration of influent: the ammonia nitrogen concentration (in terms of N) of the culture medium during the cultivation of nitrifying bacteria in the prior art is generally selected to be 300-500 mg / L, and there are rarely reports of more than 1000 mg / L. However, by selecting suitable carriers and neutralizing agent integrated materials, the ammonia nitrogen concentration (in terms of N) of the initial culture medium can be controlled to be 2500-3500 mg / L for stable operation. By providing high-concentration ammonia nitrogen influent, the high-speed reaction and growth of nitrifying bacteria are maintained, and the discharge water volume is reduced, which is beneficial to subsequent concentration and recovery of nitrate.

[0027] (2) Simultaneous fermentation and cultivation of AOB and NOB to improve raw material utilization: by controlling the effluent ammonia nitrogen and nitrite concentration to be less than 50 mg / L during cultivation. The culture medium only provides high-concentration ammonia nitrogen, which is converted to nitrite by ammonia-oxidizing bacteria to provide raw materials for nitrite-oxidizing bacteria. At the same time, NOB removes the product inhibition of AOB by metabolizing nitrite to nitrate. Unlike the prior art, which usually separately cultivates ammonia-oxidizing bacteria or nitrite-oxidizing bacteria, the ammonia nitrogen is not fully utilized, or sodium nitrite or other high-toxicity compounds are added as the source of the culture medium. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 Influent and effluent of ammonium chloride-water magnesium phosphate for cultivating AOB and NOB in a 200L device;

[0029] Figure 2 Influent and effluent of ammonium chloride-water magnesium phosphate for cultivating AOB and NOB in a 200L device;

[0030] Figure 3 Influent and effluent of ammonium chloride-water magnesium phosphate for cultivating AOB and NOB in a 200L device;

[0031] Figure 4 Influent and effluent of ammonium chloride-water magnesium phosphate for cultivating AOB and NOB in a 200L device; DETAILED DESCRIPTION

[0032] The preferred embodiments of the present application are described below, and it should be understood that the preferred embodiments described herein are only used to illustrate and explain the present application, and are not used to limit the present application.

[0033] Autotrophic nitrifying bacteria generally include two types of functional bacteria, ammonia-oxidizing bacteria and nitrite-oxidizing bacteria, both of which belong to strict autotrophic metabolism and have the characteristics of adhering growth. At the same time, when ammonia-oxidizing bacteria metabolize ammonia nitrogen, a large amount of hydrogen ions are produced, resulting in rapid pH drop of the culture medium. When the pH is lower than 7.0, the metabolic activity of ammonia-oxidizing bacteria rapidly decreases, and the growth is severely inhibited. Therefore, it is of great significance to find an economic carrier suitable for nitrifying bacteria and a material with good neutralizing ability to provide the growth pH of nitrifying bacteria. In addition, both types of bacteria belong to strict autotrophic metabolism, and need to use carbon dioxide to synthesize their own cells during growth, so a certain amount of soluble carbonate or carbon dioxide should be present in the culture medium, which is beneficial to their propagation. At present, most of the published literature and standard guidelines usually recommend sodium carbonate and sodium bicarbonate with good water solubility as pH neutralizing agents and inorganic carbon sources in nitrifying bacteria culture medium, because sodium carbonate has the advantages of wide source, good solubility, and fast utilization rate of nitrifying bacteria. It is generally believed that insoluble carbonates such as limestone, calcium carbonate, magnesium carbonate, etc. cannot provide carbon sources and neutralize the acid produced by nitrification reaction because they are almost insoluble in water.

[0034] The scheme of the present application selects natural water magnesite and synthetic water magnesite as carrier and inorganic carbon source, pH neutralizing agent integrated material, which can rapidly react with dilute hydrochloric acid (for example 1 mol / L) at room temperature (about 20℃), and the pH value after mixing with water is about 7.5-8.0 pH, the alkalinity is lower than that of chemically synthesized light magnesium carbonate and light calcium carbonate, and higher than that of heavy calcium carbonate prepared from limestone and heavy magnesium carbonate prepared from magnesite, which can meet the pH value required for normal work of nitrifying bacteria.

[0035] The water magnesite with neutral to weak alkaline (pH 7.5-8.0) in water is selected as the carrier and alkalinity neutralizing agent of autotrophic nitrifying bacteria, which solves the problems of high pH after soaking with alkaline magnesium carbonate (light magnesium carbonate) and further increasing of solution culture medium pH after aeration. By using the carrier and inorganic carbon source, pH neutralizing agent integrated material method, the nitrifying bacteria are gradually domesticated and cultured, and when the nitrifying bacteria reach a certain concentration, the water magnesite is further dissolved, achieving the purpose of mutual cooperation, which overcomes the problem that insoluble carbonates cannot be used as the only alkalinity source in the conventional understanding.

[0036] Example 1

[0037] Under the same conditions, the effects of different sources of carbonates as carrier / neutralizing agent integrated materials on the activity of nitrifying bacteria are compared by using commercially available autotrophic nitrifying bacteria, and the ammonia nitrogen degradation rate is used for judgment.

[0038] In a 1L graduated cylinder, inoculate 100ml of autotrophic nitrifying bacteria agent liquid, and place a 2cm diameter sand gas head. First add the prepared solution with an ammonia nitrogen concentration of 260mg / L, and after 1d of aeration to activate, start the experiment.

[0039] After 1h of standing, the supernatant was discharged from the 1L graduated cylinder. 500ml of prepared ammonia nitrogen simulated wastewater was added every day, and the initial ammonia nitrogen concentration was controlled at about 520mg / L, while 8 times the mass of carbonate powder was added. Aeration was started for 20h, and after the end, the ammonia nitrogen and nitrite concentrations of the supernatant were measured. When the ammonia nitrogen and nitrite concentrations were both less than 10mg / L, the ammonia nitrogen of the influent of this experimental group was increased by 130mg / L each time. When the ammonia nitrogen and nitrite concentrations were both higher than 50mg / L after the end, the ammonia nitrogen and carbonate concentration of the influent of this experimental group was decreased. The culture temperature was controlled at 26-28℃, and the same aerator with different gas outlets was used to control the uniformity of the gas supply.

[0040] Autotrophic nitrifying bacteria: ECM-410L from Wuxi Yingchuan Environmental Technology Co., Ltd. This product is a composite preparation containing nitrosation bacteria and nitrifying bacteria, with an ammonia oxidation rate of 252mgNH3-N / Lh and a nitrite oxidation rate of 224mgNO2-N / Lh.

[0041] Heavy calcium carbonate: purchased from Guangxi Zhuang Autonomous Region Junhui High Polymer Technology Co., Ltd., 2000 mesh, calcium carbonate content > 98%;

[0042] Light calcium carbonate: purchased from Jiujiang Lianxing Chemical Industry, 2000 mesh, volume ratio 2.2ml / g;

[0043] Hydromagnesite: purchased from Tibe Autonomous Region Dadai Material Technology Co., Ltd., 500 mesh, main component 3MgCO3·Mg(OH)2·3H2O, magnesium oxide content > 45%;

[0044] Magnesite powder: purchased from Liaoning Haicheng Xinhua Magnesium Products, 2000 mesh, magnesium carbonate content > 97%;

[0045] Hydrated basic magnesium carbonate: purchased from Hebei Xi Magnesium Biology, 500 mesh, magnesium oxide content > 40%;

[0046] Light magnesium carbonate: purchased from Jiangsu Ze Hui Magnesium-based New Materials, 500 mesh, magnesium oxide content > 40%, bulk density 0.52;

[0047] Sodium carbonate and sodium bicarbonate are analytical reagents, purchased from National Pharmaceutical Reagent Group.

[0048] Group 1-0 is the control group, and 1:1 mass of sodium carbonate and sodium bicarbonate is added as a neutralizing agent.

[0049] Experimental simulated ammonia nitrogen wastewater formula:

[0050] Ammonium chloride: 1.0-15.0 g, dipotassium hydrogen phosphate: 0.1 g, ferrous sulfate heptahydrate: 10 mg, manganese chloride tetrahydrate: 0.2 mg, tap water 1 L;

[0051] Each group of experiments was replaced with 500 ml of water every day, and aeration was performed for 20 h, after which the supernatant ammonia nitrogen and nitrite were measured. Each concentration was repeated three times, and the average value was taken as the final effluent data. The ammonia nitrogen loading was increased by 130 mg / L each time, and the effluent was stable for 3 days before the next increase.

[0052] (1) When the influent ammonia nitrogen concentration was 520 mg / L, 500 ml was added every day, and the conditions of each experimental group were as follows:

[0053]

[0054] As can be seen from the above table, when the influent concentration was 520 mg / L (provided by ammonium chloride), the amount of carbonate added was 1.8 g, and the magnesite powder group performed poorly. It was speculated that this was due to the slow dissolution of the heavy magnesium carbonate, the slow reaction with dilute acid at room temperature, and the weak pH adjustment ability, resulting in a low pH during the nitrification process, which inhibited the nitrification reaction. The magnesite experiment group was stopped in the subsequent experiment.

[0055] (2) When the influent ammonia nitrogen concentration was 1040 mg / L, 500 ml was added every day, and the conditions of each experimental group were as follows:

[0056]

[0057] As can be seen from the above table, when the influent ammonia nitrogen concentration (provided by ammonium chloride) was 1040 mg / L, 500 ml of water was replaced every day, and the amount of carbonate added was 3.6 g per day. Light calcium carbonate and water magnesite group performed well, and basically could completely degrade ammonia nitrogen and nitrite within 20 h. Due to the low activity of heavy calcium carbonate, the alkalinity release speed was slower than the utilization speed of ammonia-oxidizing bacteria when the influent ammonia nitrogen concentration was high, resulting in high residual ammonia nitrogen in the effluent and low pH. The hydrated basic magnesium carbonate and light magnesium carbonate, sodium carbonate groups were inhibited by the alkaline solution, resulting in high effluent ammonia nitrogen and nitrite, and the effluent pH was higher than 8.0.

[0058] (3) When the influent ammonia nitrogen concentration was 1300 mg / L, 500 ml was added every day, and the conditions of each experimental group were as follows:

[0059]

[0060]

[0061] From the above table, it can be seen that when the influent ammonia nitrogen concentration is 1300 mg / L (provided by ammonium chloride), the water is replaced by 500 ml per day, and the carbonate addition amount is 5.2 g per day. The water magnesite group performs better, and can basically completely degrade ammonia nitrogen and nitrite within 20 h. The 2000 mesh light calcium carbonate has lower acid reactivity than water magnesite, or other unknown reasons, and cannot reduce the ammonia nitrogen to below 50 mg / L within 20 h when the influent ammonia nitrogen concentration is 1300 mg / L.

[0062] (4) Water magnesite group when the influent ammonia nitrogen concentration is 1560-3900 mg / L, 500 ml per day, and the water condition:

[0063] From the above table, it can be seen that when the influent ammonia nitrogen concentration is 1560-3640 mg / L (ammonia nitrogen is provided by ammonium chloride), the water is replaced by 500 ml per day, and the carbonate addition amount is 6.2-14.5 g per day. The water magnesite group performs better, and can basically completely degrade ammonia nitrogen and nitrite within 20 h. When the influent ammonia nitrogen concentration reaches 3900 mg / L, and 500 ml is added per day, the mixed ammonia nitrogen is about 1950 mg / L. Due to the high ammonia nitrogen concentration and initial pH, a large amount of free ammonia is produced, which causes serious inhibition of AOB and NOB, and the effluent ammonia nitrogen and nitrite rise sharply, and the nitrification system collapses.

[0064] From the comparison experiment of the three groups in Example 1, it can be seen that when ammonium chloride is used as the ammonia nitrogen source in the culture medium, water magnesite and light calcium carbonate are used as the nitrifying bacteria carrier, inorganic carbon source and neutralizing agent integrated material, the nitrifying bacteria have high tolerance to ammonia nitrogen, especially water magnesite, which can increase the influent ammonia nitrogen concentration to 3600 mg / L.

[0065] Example 2

[0066] Using ultra-fine light calcium carbonate as a nitrifying bacteria culture integrated material, the nitrifying bacteria culture effect under different ammonia nitrogen source substrates (ammonium bicarbonate, ammonium chloride) is compared.

[0067] Light calcium carbonate: several specifications of materials with particle sizes of 800 mesh, 1250 mesh, 2000 mesh, 5000 mesh and 8000 mesh are selected for experiments. Water magnesite selects 500 mesh powder.

[0068] The source of nitrifying bacteria is the same as that of Experiment 1, and ECM-410L is used for experiments.

[0069] In a 1 L graduated cylinder, 100 ml of autotrophic nitrifying bacteria agent liquid is inoculated, and a 2 cm diameter sand gas head is placed. The first time, a solution with an ammonia nitrogen concentration of 260 mg / L is added, and after 1 d of aeration for activation, the experiment begins.

[0070] After 1L measuring cylinder was placed for 1h, 500ml supernatant was discharged. 500ml prepared ammonia nitrogen simulation wastewater was supplemented every day. Each experimental batch was aerated for 20h every day, and the ammonia nitrogen and nitrite concentrations of supernatant were determined after the experiment. When the ammonia nitrogen and nitrite concentrations were both lower than 10mg / L, the ammonia nitrogen of the experimental group was increased, and the concentration was increased by 130mg / L each time. When the ammonia nitrogen and nitrite concentrations were both higher than 50mg / L after the experiment, the ammonia nitrogen and carbonate concentration of the experimental group were decreased. The culture temperature was controlled at 26-28℃, and the same aerator with different air outlets was used to control the uniformity of air supply.

[0071] (1) Select 2000 mesh light calcium carbonate as the integrated material for nitrobacteria cultivation, and compare the cultivation of nitrobacteria under the same ammonia nitrogen concentration when the ammonia nitrogen is provided by ammonium chloride and ammonium bicarbonate:

[0072] When ammonium chloride is used as the ammonia nitrogen source, the amount of light calcium carbonate added is 8 times the mass of ammonia nitrogen (calculated as N). When ammonium bicarbonate is used as the ammonia nitrogen source, the amount of light calcium carbonate added is 3.5 times the mass of ammonia nitrogen (calculated as N).

[0073]

[0074] As can be seen from the above table, when the influent ammonia nitrogen concentration is 1040-2080mg / L (provided by ammonium chloride or ammonium bicarbonate), the same 2000 mesh light calcium carbonate is used as the carrier for nitrobacteria and the integrated material for neutralizing agent, and the nitration effect of the ammonium bicarbonate group is obviously better than that of the ammonium chloride group, and the effluent ammonia nitrogen and nitrite concentrations are basically lower than 10mg / L, while the ammonium chloride group begins to collapse when the concentration exceeds 1300mg / L. The reason is that ammonium bicarbonate itself can provide part of the alkalinity and carbonate, which can make up for the disadvantage of slow release of alkalinity of light calcium carbonate. By combining ammonium bicarbonate with light calcium carbonate, the disadvantage of light calcium carbonate relative to water magnesite in adapting to high concentration of ammonia nitrogen can be solved.

[0075] (2) Select ammonium bicarbonate as the ammonia nitrogen source in the culture medium, and compare the nitration effect of light calcium carbonate with different particle sizes as the carrier for nitrobacteria and the integrated material for neutralizing agent:

[0076] The experimental influent ammonia nitrogen concentration was 2080mg / L (provided by ammonium bicarbonate), and the amount of light calcium carbonate added was 3.64g. Each batch was replaced with 500ml, and the ammonia nitrogen concentration after mixing was 1040mg / L. The supernatant ammonia nitrogen and nitrite nitrogen were determined after 20h of aeration reaction. At the same time, the volume after 30min of sedimentation and the turbidity of supernatant were compared to evaluate the comprehensive performance of the material.

[0077] Experimental results:

[0078]

[0079] From the above table, when the influent ammonia nitrogen concentration is 2080 mg / L (provided by ammonium bicarbonate), the nitrification effect is good when the particle size of light calcium carbonate is greater than 2000 mesh, such as 2000-8000 mesh, and the residual ammonia nitrogen and nitrite concentration is less than 10 mg / L after 20 h aeration. When the particle size is greater than 1250 mesh, the nitrification effect is not good, which may be due to the large particle size, low specific surface area, and low release rate of carbonate, which leads to the inability of nitrifying bacteria to quickly obtain the required carbon source and neutralize the acid produced by nitrification reaction, resulting in the nitrification speed being affected. In addition, when the particle size of light calcium carbonate is less than 5000 mesh, such as 8000 mesh, it will cause the volume of the nitrification culture after precipitation to be too large, which is not conducive to subsequent separation, and the particle size is too small, which will increase the preparation cost. Therefore, it is more appropriate to choose light calcium carbonate with a particle size of 1500-5000 mesh as the nitrifying bacteria attached carrier and neutralizer integrated material.

[0080] (1) Select ammonium chloride as the ammonia nitrogen source in the culture medium, and compare the effects of different proportions of light calcium carbonate and water magnesium on nitrifying bacteria culture and effluent.

[0081] The influent ammonia nitrogen concentration was 2080 mg / L (provided by ammonium chloride), and the total amount of superfine light calcium carbonate and water magnesium was 8.4 g. The water was changed by 500 ml each batch, and the ammonia nitrogen concentration after mixing was 1040 mg / L. The supernatant ammonia nitrogen and nitrite nitrogen were measured after 20 h aeration.

[0082]

[0083] From the above table, when the influent ammonia nitrogen concentration is 2080 mg / L (provided by ammonium chloride), 500 ml of water is added every day, and after 20 h aeration, when the proportion of light calcium carbonate in the entire integrated material is greater than 33%, the effluent ammonia nitrogen cannot meet the requirement of less than 50 mg / L. Therefore, when non-ammonium bicarbonate is used as the ammonia nitrogen source, the weight proportion of light calcium carbonate in the integrated material should not exceed 33%.

[0084] Example 3

[0085] The experimental materials and methods are the same as in Example 1. The water magnesium-nitrifying bacteria culture inoculated in Example 1 is used to inoculate different experimental groups to evaluate the particle size of water magnesium.

[0086] Different particle sizes of water magnesium are selected for comparative experiments to analyze the effect of particle size on nitrifying bacteria culture.

[0087] Natural water magnesium: several specifications of materials with particle sizes of 80, 100 mesh, 200 mesh, 400 mesh, 800 mesh, 1250 mesh, 2000 mesh, and 5000 mesh are selected for experiments.

[0088] Water concentration of ammonia nitrogen is 3120 mg / L, water magnesite added amount is 12.5 g, each batch of water 500 ml, the mixed ammonia nitrogen concentration is 1560 mg / L, after 20 h of aeration reaction, the supernatant ammonia nitrogen and nitrite nitrogen are measured. At the same time, the volume after 30 minutes of sedimentation and the turbidity of the supernatant are compared to evaluate the performance of the material. The experimental results are as follows:

[0089]

[0090] From the above table, under the conditions of ammonia nitrogen concentration of 3120 mg / L, water magnesite added amount of 12.5 g, each batch of water 500 ml, mixed ammonia nitrogen concentration of 1560 mg / L, and aeration reaction for 20 h, when the particle size of water magnesite is greater than 200 mesh, such as 80-100 mesh, the treatment effect becomes poor, and the residual concentration of ammonia nitrogen is higher than 50 mg / L within 20 h, and the residual concentration of nitrite is also higher. In addition, when the particle size of water magnesite reaches 5000 mesh, the sediment volume after aeration is large. At the same time, the smaller the particle size, the greater the preparation cost. Therefore, the material with particle size range of 100-5000 mesh is selected as the nitrobacteria carrier, and further, the water magnesite powder with particle size range of 200-2000 mesh is selected as the nitrobacteria carrier, which is more appropriate.

[0091] Example 4

[0092] The nitrobacteria purified by the strain preservation center is used, and 325 mesh corn cob powder, 500 mesh natural water magnesite, calcium carbonate and basic magnesium carbonate mixed crystal microcarrier are selected for comparison under the same conditions, and the ammonia nitrogen concentration in the influent and effluent and the nitrification rate are measured for evaluation.

[0093] The preparation of calcium carbonate and basic magnesium carbonate mixed crystal microcarrier refers to the patent CN201811177583.X, and the specific preparation method is as follows:

[0094] The specific preparation method is as follows: 300 mL of 0.05 mol / L Na2CO3 solution, 150 mL of 0.08 mol / L CaCl2 solution and 150 mL of 0.03 mol / L MgCl2 solution are prepared, the CaCl2 and MgCl2 solutions are mixed, 30 mL of 1.0 g / L PAA solution is added to the Na2CO3 solution and the mixed solution of CaCl2 and MgCl2 respectively, and low-speed stirring is carried out for 0.5 h. The SDS solution is only added to the flask containing the mixed solution of Na2CO3 and PAA, and the final concentration of SDS is 15 mM. The stirring speed is adjusted to 200 r / min, the mixed solution of CaCl2 and PAA is quickly poured into the three-necked flask, and the reaction is maintained at 50°C and a stirring speed of 200 r / min for 1.2 h. The obtained precipitated product is filtered, washed with deionized water and anhydrous ethanol for 2 times respectively, and then placed in a vacuum drying box at 80°C for drying for 24 h to obtain calcium carbonate and basic magnesium carbonate mixed crystal microcarriers.

[0095] Experimental strain: First, the culture of Nitrosospira multiformis ATCC 25196 was mixed and cultured in ATCC 0929 nitrosobacteria culture medium. The formula of ATCC 0929 culture medium is as follows:

[0096] Deionized water …………………………………………1.0 L

[0097] Ammonium sulfate ………………………………………1.32 g

[0098] MgSO4 x 7H2O …………………………………………380.0 mg

[0099] CaCl2 x 2H2O …………………………………………20.0 mg

[0100] MnCl2 x 4H2O …………………………………………200.0 μg

[0101] Na2MoO4 x 2H2O ……………………………………100.0 μg

[0102] CoCl2 x 6H2O …………………………………………2.0 μg

[0103] ZnSO4 x 7H2O …………………………………………100.0 μg

[0104] KH2PO4 ………………………………………………87.0 mg

[0105] Phenol red 0.5% (See below) 0.25 mL

[0106] Chelated iron solution 1.0 mL

[0107] After sterilization at 121°C for 15 minutes, the pH was adjusted to 7.5 using 0.5 M potassium carbonate solution.

[0108] The above strains were cultured in the recommended medium, and after the ammonia nitrogen consumption was completed, fresh culture was supplemented for continuous culture, and the culture was continued for 1 month until the biomass no longer increased significantly.

[0109] Take 10% inoculation to 250 mL shake flask, add the recommended medium, add three kinds of microcarriers to each bottle 2.0 g in the experimental group, and do not add microcarriers in the control group. Sodium bicarbonate is used as the alkalinity agent in the control group and the corn cob powder carrier group, and the pH is naturally maintained in the water and magnesium carbonate group and the mixed crystal group, and no potassium carbonate solution is added to adjust the pH. After 6 hours of culture at 25°C on a shaker at 200 rpm, the water ammonia nitrogen concentration was determined. Three parallel groups were set up for each experimental group, and the average value of the three groups was taken as the water data as follows.

[0110] The experimental results are as follows:

[0111]

[0112]

[0113] As can be seen from the above table, using water and magnesium carbonate as a nitrifying bacteria carrier and alkalinity integrated material has obvious advantages, and the water ammonia nitrogen is significantly lower than that of the calcium carbonate-alkali magnesium carbonate mixed crystal group and the corn cob powder as the carrier group. And water and magnesium carbonate is derived from nature, there is no secondary pollution, and it has no toxicity to biology.

[0114] Example 5

[0115] Two 200L pilot batch cultures of ammonia-oxidizing bacteria and nitrite-oxidizing bacteria were carried out, using 500 mesh water and magnesium carbonate and 2000 mesh light calcium carbonate as nitrifying bacteria culture carriers and inorganic carbon source, pH neutralizer integrated materials. The bottom of the reactor was supplied with oxygen by a microporous frosted aeration disc, and the dissolved oxygen was controlled at 2.0-4.0 mg / L, and the culture temperature was 25-28°C. When the effluent ammonia nitrogen and nitrite concentration was lower than 50 mg / L, the load was increased after 3 batches were stabilized. Each batch was 22 hours of aeration, 1 hour of sedimentation, and 1 hour of water feeding (with aeration). In addition to ammonium chloride or ammonium bicarbonate providing ammonia nitrogen, 0.1 g / L of potassium dihydrogen phosphate, 0.01 g / L of ferrous sulfate, and 0.001 g / L of sodium molybdate were added to the water culture medium, and the rest was supplemented with tap water.

[0116] System 1 uses ammonium chloride as the ammonia nitrogen source in the culture medium, 500 mesh water magnesite nitrifying bacteria culture carrier, alkalinity, inorganic carbon source integrated material, inoculation using 500 mesh water magnesite as carrier material domestication in example 3, can be within 20h degradation of ammonia nitrogen concentration of 3120mg / L nitrifying bacteria culture inoculation, inoculation amount is 10% of the reactor. After standing and precipitating for 1h every day, 100L of water is drained, and then 100L of prepared high ammonia nitrogen medium is added. The water concentration of system 1 is estimated to be 260mg / L according to the ammonia nitrogen concentration of 1g / L ammonium chloride, and the medium preparation concentration is estimated. This 200L device is supplemented with polymeric ferric sulfate once a week, and the addition amount is 10g. After dissolving in 100ml tap water, it is directly added to the nitrification reactor, and 1L of anion PAM with a concentration of one ten-thousandth is added after complete mixing. Supplementing polymeric ferric sulfate and PAM once a week is beneficial to improving the stability of nitrification flocs and preventing strain loss. System 2 uses ammonium bicarbonate as the ammonia nitrogen source in the culture medium, 2000 mesh light calcium carbonate as the nitrifying bacteria culture carrier, alkalinity, inorganic carbon source integrated material, inoculation using 2000 mesh light calcium carbonate as carrier material culture in example 2, can be within 20h degradation of ammonia nitrogen concentration of 2080mg / L nitrifying bacteria culture inoculation, inoculation amount is 10% of the reactor. After standing and precipitating for 1h every day, 100L of water is drained, and then 100L of prepared high ammonia nitrogen medium is added. The water concentration of system 2 is estimated to be 171mg / L according to the ammonia nitrogen concentration of 1g / L ammonium bicarbonate, and the medium preparation concentration is estimated. This 200L device is supplemented with polymeric ferric sulfate once a week, and the addition amount is 12g. After dissolving in 120ml tap water, it is directly added to the nitrification reactor, and 1L of anion PAM with a concentration of one ten-thousandth is added after complete mixing. Supplementing polymeric ferric sulfate and PAM once a week is beneficial to improving the stability of nitrification flocs and preventing strain loss.

[0117] The ammonia nitrogen of the influent, the ammonia nitrogen of the effluent, the nitrite concentration of the effluent and the volumetric loading of systems 1 and 2 during the culture process are referred to the attached Figures 1-4 .

[0118] From the attached Figures 1-2 It can be seen that during the culture of nitrifying bacteria with ammonium chloride-water magnesite, when the influent ammonia nitrogen concentration is less than 2600mg / L, the addition amount of water magnesite is 8 times that of ammonia nitrogen, and ammonia nitrogen and nitrite can be completely consumed within 24h without accumulation; when the ammonia nitrogen concentration exceeds 2600mg / L, the effluent ammonia nitrogen and nitrite rise sharply, and the system has a tendency to collapse. The maximum volumetric loading of ammonia nitrogen of the final system reaches 1.3kgNH3-N / m 3 d. From the attached Figures 3-4As can be seen, during the process of culturing nitrifying bacteria with ammonium bicarbonate-light calcium carbonate, when the ammonia nitrogen concentration of the influent is less than 2565 mg / L, the dosage of light calcium carbonate is 0.6 times that of ammonium bicarbonate, and ammonia nitrogen and nitrite can be completely consumed within 24 h without accumulation; when the ammonia nitrogen concentration exceeds 2700 mg / L, the effluent ammonia nitrogen and nitrite rise sharply, and the system has a tendency to collapse. The maximum nitrification volumetric load after cultivation reaches 1.28 kgNH3-N / m 3 d.

[0119] The ammonia nitrogen concentration of the influent of system 1 after cultivation is 2600 mg / L, and the ammonia nitrogen removal load is 1.3 kgNH3-N / m

[0120] 1.3 kgNH3-N / m 3 d of nitrifying bacteria culture is discharged from the reactor, and after standing and precipitating for 24 h in a 4°C refrigerator, 20 L of nitrifying bacteria culture is concentrated and sealed and stored in a 4°C refrigerator to avoid light. The ammonia nitrogen concentration of the influent of system 2 after cultivation is 2560 mg / L, and the ammonia nitrogen removal load is 1.28 kgNH3-N / m 3 d of nitrifying bacteria culture is discharged from the reactor, and after standing and precipitating for 24 h in a 4°C refrigerator, 20 L of nitrifying bacteria culture is concentrated and sealed and stored in a 4°C refrigerator to avoid light.

[0121] The ammonia oxidation rate of the nitrifying bacteria culture is determined according to the method of “HGT 5748-2020 Performance Evaluation Method for Nitrifying Bacteria for Water Treatment”; the method for determining the nitrite oxidation rate of the nitrifying bacteria culture is similar to the method for determining the ammonia oxidation rate, and the ammonium chloride in the activated culture medium is replaced with sodium nitrite with a mass concentration of 2000 mg / L, and the rest remains unchanged; the ammonium chloride in the test culture medium is replaced with sodium nitrite with a mass concentration of 200 mg / L, and the rest remains unchanged.

[0122] The ammonia oxidation rate and nitrite oxidation rate of the two groups of concentrated nitrifying bacteria cultures are as follows:

[0123]

[0124]

[0125] As can be seen from the above table, the nitrifying bacteria compositions cultured with ammonium chloride-water magnesite and ammonium bicarbonate-light calcium carbonate can have an ammonia oxidation rate and nitrite oxidation rate of more than 200 mg / Lh after being concentrated by 5 times.

[0126] The above merely describes the preferred embodiments of the present application, but the protection scope of the present application is not limited thereto, and any person skilled in the art can easily think of changes or replacements within the technical scope disclosed by the present application, which should be covered in the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A method of synchronously culturing ammonia-oxidizing bacteria and nitrite-oxidizing bacteria, characterized by, The application relates to a pH neutralizer, inorganic carbon source and growth-attached carrier integrated material for culturing nitrifying bacteria, which is mainly composed of one or more than two kinds of mixtures of water-magnesite powder, water-magnesite powder and superfine calcium carbonate; the mass ratio of ammonia nitrogen to the pH neutralizer, inorganic carbon source and growth-attached carrier integrated material is 1:2-1:15; the culture medium is put into a reactor; and a high-density active ammonia-oxidizing bacteria and nitrite-oxidizing bacteria aggregate is cultured.

2. The method of claim 1, wherein the method is characterized by, The pH neutralizer, inorganic carbon source and growth-attached carrier integrated material can be added at one time or in batches, or be mixed in the water in advance and be continuously added through the water.

3. The method of claim 1, wherein the method is characterized by, When the sequencing batch fermentation is adopted, the ammonium salt or inorganic carrier as alkalinity agent can be added at one time or in batches; after the supernatant is separated, the nitrifying bacteria culture is reserved; when the continuous water feeding is adopted, the powder culture solution containing ammonia nitrogen and the pH neutralizer, inorganic carbon source and growth-attached carrier integrated material is prepared according to the proportion, and then the culture solution is continuously added to the culture device; the culture is subjected to sludge-water separation; and the cultured flocculent nitrifying bacteria aggregate is intercepted.

4. The method of claim 1, wherein the method is characterized by, The main chemical components of the hydromagnesite are represented by xMgCO3.yMg(OH)2.zH2O, wherein the value of x is 3 or 4, the value of y is 1, and the value of z is 0-5; the hardness of the hydromagnesite is 3.0-4.0, the density is 2.0-2.4 g / cm 3 ; and the particle size of the hydromagnesite is 100-5000 mesh.

5. The method of claim 1, wherein the method is characterized by, When the proportion of superfine light calcium carbonate in the pH neutralizer, inorganic carbon source and growth-attached carrier integrated material for culturing nitrifying bacteria is greater than 33%, the ammonia nitrogen in the culture medium is provided by ammonium bicarbonate; the particle size of the superfine light calcium carbonate is 1500-6000 meshes; the average particle size is less than 7.5 microns; the bulk specific gravity is 1.8-4.5 ml / g; and the pH value of 1% water solution is less than 10.

8.

6. The method of claim 1, wherein the method is characterized by, The ammonia-oxidizing bacteria are selected from bacteria of the Nitrosomonadaceae family, which includes the Nitrosomonas genus, the Nitrosococcus genus, the Nitrosospira genus and the Nitrosospira genus; the nitrite-oxidizing bacteria are selected from the Nitrobacter genus and the Nitrospira genus; the ammonia-oxidizing bacteria and the nitrite-oxidizing bacteria can be artificially separated pure bacteria or mixed culture containing the functional bacteria obtained from the nature; and the mixed culture refers to the autotrophic ammonia-oxidizing bacteria and nitrite-oxidizing bacteria culture which is long-term domesticated and cultured by using ammonia nitrogen or nitrite without adding other organic matters.

7. The method of claim 1, wherein the method is characterized by, The ammonia nitrogen is provided by one or more than two kinds of mixtures of ammonium chloride, ammonium sulfate, ammonium bicarbonate, ammonium nitrate and ammonia water; when the proportion of light calcium carbonate in the pH neutralizer, inorganic carbon source and growth-attached carrier integrated material is greater than 33%, the ammonia nitrogen is provided by ammonium bicarbonate; the ammonia nitrogen concentration in the culture medium is controlled to be 500-4000 mg / L in terms of N; and the nitrate nitrogen concentration in the discharge liquid after the culture is completed or in the continuous culture is controlled to be less than 6500 mg / L in terms of N.

8. The method of claim 1, wherein the method is characterized by, ammonia nitrogen concentration in the effluent is less than 50 mg / L, nitrite nitrogen concentration is less than 50 mg / L, dissolved oxygen concentration is controlled in the range of 1.0-6.0 mg / L, temperature is in the range of 10-45 °C, pH is in the range of 6.0-9.0, ammonia nitrogen volumetric loading is in the range of 0.25-2.5 kg NH3-N / m 3 d; when ammonia nitrogen or nitrite concentration is higher than 50 mg / L, the culture time is delayed or the influent flow is reduced until the concentration is less than 50 mg / L, and the ammonia nitrogen volumetric loading is increased by 0.05-0.3 kg NH3-N / m 3 d, and the next loading increase operation is performed after stable operation for 2-5 days under the same loading.

9. The method of claim 1, wherein the method is characterized by, The nitrifying bacteria aggregate after the culture has an ammonia-oxidizing rate of 30-150 mgNH3-N / Lh and a nitrite-oxidizing rate of 20-120 mgNO2-N / Lh; the culture is concentrated by gravity, centrifugation or membrane concentration to obtain a commercial nitrifying bacteria agent with an ammonia-oxidizing rate of greater than 200 mgNH3-N / Lh and a nitrite-oxidizing rate of greater than 150 mgNO2-N / Lh, which contains residual water-magnesite and calcium carbonate as the carrier mixed in the nitrifying bacteria agent.

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