Nitrobacter potentiator, method of preparation and use thereof

Abstract

The application relates to the field of industrial wastewater treatment, in particular to a nitrifying bacteria synergist, a preparation method and application thereof. The nitrifying bacteria synergist comprises the following components in mass ratio: 5%-10% of a composite enzyme preparation, 80%-90% of nitrifying bacteria and 2%-5% of sludge ash. The sludge ash is inorganic ash obtained by calcining municipal wastewater active sludge. The nitrifying bacteria synergist can realize rapid startup and stable maintenance of the nitrification function, and can effectively avoid the risk of exceeding the standard of heavy metal ions in effluent caused by excessive addition.

Description

Technical Field

[0001] This application relates to the field of industrial wastewater treatment, specifically to a nitrifying bacteria synergist, its preparation method, and its application. Background Technology

[0002] In biological nitrogen removal from wastewater, nitrification (the oxidation of ammonia nitrogen to nitrate nitrogen) is the key rate-limiting step, and its efficiency mainly depends on the activity and quantity of nitrifying bacteria (including ammonia-oxidizing bacteria AOB and nitrite-oxidizing bacteria NOB). However, nitrifying bacteria grow slowly and are sensitive to environmental factors (such as pH fluctuations, low temperature, nutrients, and toxic substances). In practical engineering, industrial wastewater treatment systems are prone to nitrification system collapse, leading to excessive ammonia nitrogen levels in the effluent.

[0003] To enhance nitrification, existing technologies mainly include: 1. Inoculating the system with a large amount of sludge with good nitrification activity. Although this method is direct, it involves the inter-plant transfer and disposal of excess sludge, which is complicated and costly. Furthermore, the activity of the inoculated sludge is easily reduced during transportation and storage, resulting in unstable effects. 2. Directly adding chemical trace elements (such as iron, copper, and cobalt salts) and other growth factors to the wastewater. While this method can stimulate the activity of nitrifying bacteria to some extent, long-term use is costly, and excessive addition poses an environmental risk of heavy metal ion contamination in the effluent. 3. Adding pure cultured nitrifying bacteria agents. Commercially available nitrifying bacteria agents (usually liquid or powder) mostly use single or compound nitrifying strains, combined with protectants and a small amount of nutrients. These products mainly supplement the number of bacteria, but when exogenous agents are added to actual wastewater, they face problems such as competition with native microorganisms, long adaptation periods, and easy leaching. Their effectiveness is limited when used alone. Summary of the Invention

[0004] The purpose of this invention is to provide a nitrifying bacteria enhancer that can enable rapid start-up and stable maintenance of nitrification function, and can effectively avoid the risk of excessive heavy metal ions in the effluent due to excessive addition.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a nitrifying bacteria synergist, comprising the following components in the indicated mass ratio: Compound enzyme preparations 5%~10%, Nitrifying bacteria 80%~90%, Sludge ash content: 2%~5%; The sludge ash is divided into inorganic ash obtained by burning municipal sewage activated sludge.

[0006] Preferably, the compound enzyme preparation contains at least two of urease, dehydrogenase, and aminomonooxygenase and nitrite oxidoreductase.

[0007] Preferably, the nitrifying bacteria comprise at least one genus selected from ammonia-oxidizing bacteria and at least one genus selected from nitrite-oxidizing bacteria.

[0008] Preferably, the ammonia-oxidizing bacteria include at least one of Nitrosomonas, Nitrospirillum, and Nitrococcus; the nitrite-oxidizing bacteria include at least one of Nitrobacterium and Nitrococcus.

[0009] Preferably, the sludge ash contains silicon, calcium, magnesium, phosphorus, iron, and aluminum.

[0010] Preferably, the incineration temperature of the municipal wastewater activated sludge is 500-900℃.

[0011] This application also provides a method for preparing the above-mentioned nitrifying bacteria synergist, comprising: S1. The activated sludge from municipal sewage is calcined and then ground to obtain dry powdered sludge ash. S2. Weigh out 5%~10% of the compound enzyme preparation, 80%~90% of the nitrifying bacteria, and 2%~5% of the sludge ash by mass percentage, place them in a mixer, add pure water and stir to mix evenly to obtain the nitrifying bacteria enhancer.

[0012] Preferably, step S1 specifically includes: The dewatered activated sludge from the municipal wastewater treatment plant was dried to constant weight at 80-120℃; Heat in a muffle furnace at 500-900℃ for 1-4 hours; Grind after cooling.

[0013] The present invention also provides an application of the above-mentioned nitrifying bacteria synergist in the nitrification process of enhanced biological denitrification of industrial wastewater.

[0014] Preferably, the nitrifying bacteria synergist is added to the aerobic tank and / or nitrification filter of the industrial wastewater treatment system, and the dosage is 0.05-1.0 grams per cubic meter of wastewater to be treated.

[0015] The beneficial effects of this invention are as follows: In this nitrifying bacteria synergist, nitrifying bacteria, as the main active ingredient, can directly supplement the functional bacterial community; the compound enzyme preparation can rapidly decompose organic nitrogen compounds in wastewater, providing easily usable substrates for nitrifying bacteria, thereby shortening the adaptation period of exogenous bacterial communities; sludge ash serves as a carrier and nutrient source (growth factor), which is a nutrient lacking in industrial wastewater. Therefore, by adding it to the industrial wastewater treatment system, it is beneficial for the colonization and retention of nitrifying bacteria in the system. Through the synergistic effect of these three components, rapid start-up and stable maintenance of nitrification function can be achieved.

[0016] Furthermore, since the sludge ash originates from the inorganic ash obtained by incinerating excess sludge from municipal wastewater treatment plants, it achieves "waste treatment with waste," which helps reduce the cost of using trace elements or carriers. Moreover, compared to the direct addition of chemical trace elements (such as iron, copper, and cobalt salts) in existing technologies, using the nitrifying bacteria synergist of this application can effectively avoid the risk of excessive heavy metal ions in the effluent due to overdosing.

[0017] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, the preferred embodiments of the present invention are described in detail below with reference to the accompanying drawings. Attached Figure Description

[0018] Figure 1 This is a rate comparison graph showing the ammonia nitrogen removal efficiency of a control example using the nitrifying bacteria synergist shown in one embodiment of this application. Detailed Implementation

[0019] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of this application. Furthermore, it should be noted that, for ease of description, only the parts relevant to this application are shown in the accompanying drawings, not the entire structure. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without inventive effort are within the scope of protection of this application.

[0020] An embodiment of this application shows a nitrifying bacteria synergist comprising the following components in the indicated mass ratio: Compound enzyme preparations 5%~10%, Nitrifying bacteria 80%~90%, Sludge ash content: 2%~5%; Sludge ash is the inorganic ash obtained by burning municipal wastewater activated sludge.

[0021] In this nitrifying bacteria synergist, nitrifying bacteria serve as the main active ingredient, directly supplementing the functional microbial community. The compound enzyme preparation can rapidly decompose organic nitrogen compounds in wastewater, providing readily available substrates for nitrifying bacteria, thereby shortening the adaptation period of exogenous microbial communities. Sludge ash acts as a carrier and nutrient source (growth factor), which is a nutrient lacking in industrial wastewater. Therefore, by adding it to the industrial wastewater treatment system, it is beneficial for the colonization and retention of nitrifying bacteria in the system. Through the synergistic effect of the three, the rapid start-up and stable maintenance of nitrification function can be achieved.

[0022] Furthermore, since the sludge ash originates from the inorganic ash obtained by incinerating the excess sludge generated by the wastewater treatment plant itself, it achieves "waste treatment with waste," which helps reduce the cost of using trace elements or carriers. Moreover, compared to the direct addition of chemical trace elements (such as iron, copper, and cobalt salts) in existing technologies, the nitrifying bacteria synergist of this embodiment can effectively avoid the risk of excessive heavy metal ions in the effluent due to overdosing.

[0023] It should be noted that urban wastewater treatment plants generate a large amount of excess activated sludge during operation. This sludge mainly consists of organic matter and microbial residues. Currently, the mainstream disposal methods are dewatering followed by incineration, landfilling, or anaerobic digestion, resulting in a relatively limited resource utilization pathway. However, through the application of this application, the ash from the incineration of the aforementioned sludge can be converted into the core functional component of a nitrifying bacteria synergist, not only broadening the pathways for sludge resource utilization but also achieving "waste treatment with waste."

[0024] In one embodiment, the compound enzyme preparation comprises at least two of urease, dehydrogenase, and ammonia monooxygenase and nitrite oxidoreductase. Urease can decompose urea into ammonia nitrogen, providing a substrate for the nitrification reaction; dehydrogenase reflects the overall metabolic activity of microorganisms; ammonia monooxygenase is a key enzyme for AOB to convert ammonia nitrogen into hydroxylamine; and nitrite oxidoreductase is a key enzyme for NOB to convert nitrite into nitrate. The combination of multiple enzymes can simultaneously enhance the nitrification process from multiple levels, including substrate supply, metabolic activity, and key catalytic reactions. In this way, different enzyme combinations can be selected for different water qualities (such as urea-containing wastewater and low C / N ratio wastewater), thereby improving the applicability of the synergist.

[0025] In practical applications, different nitrifying bacteria genera exhibit varying tolerance ranges and adaptation rates to environmental factors such as temperature, pH, and dissolved oxygen. To ensure that at least some genera remain active during environmental fluctuations, in an optional embodiment, the nitrifying bacteria include at least one genera selected from ammonia-oxidizing bacteria and at least one genera selected from nitrite-oxidizing bacteria. The ammonia-oxidizing bacteria oxidize ammonia nitrogen to nitrite, and the nitrite-oxidizing bacteria further oxidize nitrite to nitrate. Preferably, the ammonia-oxidizing bacteria include, but are not limited to, at least one of Nitrosomonas, Nitrosospira, and Nitrosococcus; the nitrite-oxidizing bacteria include, but are not limited to, at least one of Nitrobacter and Nitrococcus.

[0026] The sludge ash contains at least one element selected from silicon (Si), calcium (Ca), magnesium (Mg), phosphorus (P), iron (Fe), copper (Cu), and molybdenum (Mn). Iron (Fe) is a cofactor for cytochromes and many enzymes (such as ammonia monooxygenase); magnesium (Mg) is a key element required for ATP synthesis and ribosome stability; calcium (Ca) participates in biofilm formation and signal transduction; phosphorus (P) is a core component of ATP and nucleic acids; copper (Cu) is the active site of ammonia monooxygenase (AMO) and copper-type nitrite reductase; and molybdenum (Mn) is the active site of hydroxylamine oxidase (HAO) and nitrite oxidoreductase (NXR). Silicon (Si) is a typical inorganic carrier component; its porous structure provides an attachment surface for nitrifying bacteria, which is beneficial for the formation of structurally stable biofilms.

[0027] It should be noted that the aforementioned elements are inherent components of sludge incineration ash, typically existing in specific mineral forms (such as oxides and silicates), rather than soluble salts. They are not added externally. Compared to directly adding water-soluble trace element salts, this sludge ash has the following synergistic advantages: First, the elements exist in insoluble or slightly soluble mineral forms, allowing for slow release and avoiding the potential toxicity to microorganisms from excessively high instantaneous concentrations and the problem of rapid loss with the effluent. Second, the ash itself has a porous structure, which can act as a carrier to enhance the attachment and retention of nitrifying bacteria. Finally, the alkaline oxides (such as CaO and MgO) in the ash can provide pH buffering capacity, creating a stable chemical environment for the nitrification reaction.

[0028] In one alternative embodiment, the incineration temperature of activated sludge from municipal wastewater is 500-900°C. This temperature range ensures that the organic matter and pathogenic microorganisms in the activated sludge are completely incinerated, yielding pure inorganic ash and preventing residual organic matter from competing with or inhibiting nitrifying bacteria. Moreover, compared to higher temperatures (>900°C), incineration at 500-900°C avoids excessive melting or vitrification in the ash, which helps preserve its porous structure and active mineral forms (such as CaO, MgO, Fe2O3, etc.), giving it good adsorption performance and pH buffering capacity.

[0029] This application also provides a method for preparing the above-mentioned nitrifying bacteria synergist, comprising: S1. The activated sludge from municipal sewage is calcined and then ground to obtain dry powdered sludge ash. S2. Weigh out 5%~10% of the compound enzyme preparation, 80%~90% of the nitrifying bacteria, and 2%~5% of the sludge ash by mass percentage, place them in a mixer, add pure water and stir to mix evenly, then dry and pulverize to obtain the nitrifying bacteria enhancer.

[0030] In the above preparation method, by using physical mixing at room temperature or low temperature, the destruction of enzyme preparations and nitrifying bacteria activity by high temperature or violent chemical reactions is avoided, thus ensuring the effectiveness of the product. This preparation process only involves conventional unit operations such as calcination, grinding, weighing, mixing, and stirring, without the need for complex equipment or harsh reaction conditions, which is conducive to mass production.

[0031] In one embodiment, step S1 specifically includes: The dewatered activated sludge from the municipal wastewater treatment plant is dried to constant weight at 80-120°C (e.g., 80°C, 105°C, or 120°C); Incinerate in a muffle furnace at 500-900°C (e.g., 500°C, 550°C, 600°C or 900°C) for 1-4 hours (e.g., 1 hour, 2 hours, 3 hours or 4 hours). After cooling, grind the particles until the particle size is no greater than 0.2 mm (e.g., 0.1 mm, 0.15 mm, or 0.2 mm).

[0032] In the above steps, drying the dewatered activated sludge from the municipal wastewater treatment plant at 80-120℃ effectively removes free and bound water, while preventing premature carbonization of organic matter or release of harmful gases due to excessively high temperatures. This provides homogenized material for subsequent incineration. Incineration at 500-900℃ for a specific time ensures complete combustion of organic matter in the sludge and maintains a stable mineral composition and microstructure of the ash products. Too short a time will result in incomplete incineration, while too long a time increases energy consumption and may damage the ash's activity. Controlling the grinding particle size to no more than 0.2mm facilitates uniform dispersion of the sludge ash in water, increases the contact area with nitrifying bacteria and enzyme preparations, and improves the overall effectiveness of the synergist.

[0033] The following are examples illustrating several specific formulations and preparation methods of nitrifying bacteria synergists.

[0034] Example 1:

[0035] Weigh the following by weight percentage: 5% compound enzyme preparation (containing urease and ammonia monooxygenase in a 1:1 ratio), 93% nitrifying bacteria (containing nitrosomonas, nitrosylspirulina, and nitrifying bacilli in a 1:1:1 ratio), and 2% sludge ash.

[0036] The preparation method of sludge ash is as follows: Take activated sludge (moisture content of about 80%) from a municipal sewage treatment plant after centrifugation and dewatering, and dry it to constant weight in an oven at 105℃; pulverize the dried sludge and place it in a ceramic crucible, put it in a muffle furnace, and calcine it at 550℃ for 2 hours; after cooling, take it out, grind it to a particle size of no more than 0.15mm (passing through a 100-mesh standard sieve), and seal it for later use.

[0037] The above-weighed compound enzyme preparation, nitrifying bacteria and sludge ash are placed in a mixer, pure water is added and stirred until evenly mixed, and then dried and pulverized to obtain a powdered nitrifying bacteria enhancer.

[0038] Example 2:

[0039] Weigh the following by weight percentage: 8% compound enzyme preparation (containing dehydrogenase and nitrite oxidoreductase in a mass ratio of 1:2), 87% nitrifying bacteria (containing nitrosomonas, nitrosococci, and nitrifying cocci in a mass ratio of 2:1:1), and 5% sludge ash.

[0040] The preparation method of sludge ash is as follows: Take activated sludge (moisture content of about 80%) after centrifugation and dewatering from a municipal sewage treatment plant, and dry it to constant weight in an oven at 100℃; after pulverizing the dried sludge, place it in a ceramic crucible, put it in a muffle furnace, and calcine it at 700℃ for 3 hours; after cooling, take it out, grind it to a particle size of no more than 0.1mm, and seal it for later use.

[0041] The above-weighed compound enzyme preparation, nitrifying bacteria and sludge ash are placed in a mixer, pure water is added and stirred until evenly mixed, and then dried and pulverized to obtain a powdered nitrifying bacteria enhancer.

[0042] Example 3:

[0043] Weigh the following by weight percentage: 10% compound enzyme preparation (containing urease, dehydrogenase and ammonia monooxygenase in a mass ratio of 1:1:1), 85% nitrifying bacteria (containing nitrosomonas, nitrosylspirus, nitrifying bacilli and nitrifying cocci in a mass ratio of 1:1:1:1), and 5% sludge ash.

[0044] The preparation method of sludge ash is as follows: Take activated sludge (moisture content of about 80%) after centrifugation and dewatering from a municipal sewage treatment plant, and dry it to constant weight in an oven at 120℃; pulverize the dried sludge and place it in a ceramic crucible, put it in a muffle furnace, and calcine it at 850℃ for 1.5 hours; after cooling, take it out, grind it to a particle size of no more than 0.2mm, and seal it for later use.

[0045] The above-weighed compound enzyme preparation, nitrifying bacteria and sludge ash are placed in a mixer, pure water is added and stirred until evenly mixed, and then dried and pulverized to obtain a powdered nitrifying bacteria enhancer.

[0046] The elemental composition of the nitrifying bacteria synergists prepared in Examples 1-3 was analyzed by X-ray fluorescence spectrometry (XRF), and the results are shown in Table 1.

[0047] Table 1. XRF elemental analysis results (wt%) of samples from Examples 1-3

[0048] This nitrifying bacteria enhancer is applicable to various wastewater biological denitrification processes, including but not limited to traditional activated sludge processes, sequencing batch reactors (SBRs), anoxic / aerobic (A / O) processes, and anaerobic / anoxic / aerobic (A / O) processes. 2 Oxidation ditches, moving bed biofilm reactors (MBBR), etc.

[0049] In a specific application embodiment, the nitrifying bacteria enhancer can be directly added to the core area of ​​the nitrification reaction, namely the aerobic tank and / or nitrifying filter, to maximize its effectiveness and avoid ineffective addition. The dosage is 0.05-1.0 grams per cubic meter of wastewater to be treated, and the frequency is 1-2 times per day to maintain a steady-state concentration of the effective components in the system and prevent significant fluctuations in nitrification function.

[0050] This dosage range ensures effective colonization of exogenous nitrifying bacteria and catalytic activity of enzymes, significantly improving the nitrification rate, while also balancing treatment costs and effluent quality, achieving an optimal balance between technical effectiveness and economic efficiency. It should be noted that the inventors have experimented with other dosages, but when the dosage is below 0.05 g / m³... 3 When the added nitrifying bacteria and enzymes are insufficient to form a dominant population in a complex activated sludge system, their activity is easily diluted or inhibited by native microorganisms, resulting in insignificant nitrification enhancement and an inability to effectively cope with influent load fluctuations or toxic shocks. When the dosage exceeds 1.0 g / m³... 3 While the nitrification rate may be further increased, the following problems may arise: First, excessive nitrifying bacteria and enzyme preparations will result in direct economic waste due to microbial death or loss with the effluent after the nitrification reaction is completed; second, excessively high concentrations of bacteria and their metabolites may increase the biological oxygen demand or suspended solids concentration in the effluent; finally, some components in the compound enzyme preparation (such as ammonia monooxygenase) may exhibit substrate inhibition effects when the concentration is much higher than the substrate concentration, which is not conducive to the continuous increase of the reaction rate.

[0051] To further verify the actual effect of the nitrifying bacteria synergist in this embodiment, an application effect verification experiment is given below: Two identical laboratory sequencing batch reactors (SBR, 5 L effective volume) were set up and inoculated with activated sludge from a wastewater treatment plant. Both reactors were operated continuously with synthetic wastewater (ammonia nitrogen concentration 50 mg / L). One reactor served as a control group without any additives; the other reactor served as the experimental group, with 2.5 mg / L of the nitrifying bacteria synergist prepared in this example (i.e., 2.5 g per cubic meter of water) added daily at the beginning of the aerobic phase.

[0052] After 10 days of continuous operation, the system was in a stable state. Then, wastewater with an ammonia nitrogen concentration of 30 mg / L was introduced. Ammonia nitrogen was measured every hour for 3 hours. The nitrification performance of the two reactors was compared. See the results below. Figure 1 The experimental group had an effluent ammonia nitrogen level of 8.98 mg / L after 3 hours, with an ammonia nitrogen removal rate of 68.3%; while the control group had an effluent ammonia nitrogen level of 14.4 mg / L, with a removal rate of approximately 50.9%. Under the same influent water quality and operating conditions, the only variable was the addition of a nitrifying bacteria enhancer in the experimental group, which increased the ammonia nitrogen removal efficiency by 18.5%. Simultaneously, the nitrate nitrogen concentration at the end of the aerobic stage in the experimental group was significantly higher than that in the control group, indicating a more complete nitrification process. High-throughput sequencing revealed that the gene copy number of ammonia-oxidizing bacteria (Nitrosomonas spp.) in the experimental group was approximately 3.0 times that of the control group. Therefore, the enhancer in this embodiment can effectively promote the growth and activity of nitrifying bacteria, significantly improving the nitrification efficiency of the wastewater biological denitrification system.

[0053] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0054] The above embodiments merely illustrate several implementation methods of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A nitrifying bacteria synergist, characterized in that, Includes the following components in the indicated mass ratios: Compound enzyme preparations 5%~10%, Nitrifying bacteria 80%~90%, Sludge ash content: 2%~5%; The sludge ash is divided into inorganic ash obtained by burning municipal sewage activated sludge.

2. The nitrifying bacteria synergist as described in claim 1, characterized in that, The compound enzyme preparation contains at least two of the following: urease, dehydrogenase, aminomonooxygenase, and nitrite oxidoreductase.

3. The nitrifying bacteria synergist as described in claim 1, characterized in that, The nitrifying bacteria include at least one genus selected from ammonia-oxidizing bacteria and at least one genus selected from nitrite-oxidizing bacteria.

4. The nitrifying bacteria synergist as described in claim 3, characterized in that, The ammonia-oxidizing bacteria include at least one of Nitrosomonas, Nitrospirillum, and Nitrococcus; the nitrite-oxidizing bacteria include at least one of Nitrobacterium and Nitrococcus.

5. The nitrifying bacteria synergist as described in claim 1, characterized in that, The sludge ash contains silicon, calcium, magnesium, phosphorus, iron, and aluminum.

6. The method for preparing the nitrifying bacteria synergist as described in claim 1, characterized in that, The incineration temperature of the activated sludge from the municipal wastewater is 500-900℃.

7. A method for preparing a nitrifying bacteria synergist as described in any one of claims 1-6, characterized in that, The method includes: S1. The activated sludge from municipal sewage is calcined and then ground to obtain dry powdered sludge ash. S2. Weigh out 5%~10% of the compound enzyme preparation, 80%~90% of the nitrifying bacteria, and 2%~5% of the sludge ash by mass percentage, place them in a mixer, add pure water and stir to mix evenly to obtain the nitrifying bacteria enhancer.

8. The method as described in claim 7, characterized in that, Step S1 specifically includes: The dewatered activated sludge from the municipal wastewater treatment plant was dried to constant weight at 80-120℃; Heat in a muffle furnace at 500-900℃ for 1-4 hours; Grind after cooling.

9. The application of the nitrifying bacteria synergist as described in any one of claims 1-6 in the nitrification process of enhanced biological denitrification of industrial wastewater.

10. The application according to claim 9, characterized in that, The nitrifying bacteria synergist is added to the aerobic tank and / or nitrification filter of the industrial wastewater treatment plant, and the dosage is 0.05-1.0 grams per cubic meter of wastewater to be treated.

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