Anaerobic ammonium oxidation bacteria carrier for ammonia nitrogen treatment of garbage permeate as well as preparation method and reactor of anaerobic ammonium oxidation bacteria carrier
By designing an anaerobic ammonia-oxidizing bacteria carrier consisting of a nutrient core ball, a slow-release regulation layer, and an attachment layer, the problems of low leachate treatment efficiency and slow growth of anaerobic ammonia-oxidizing bacteria in traditional processes were solved, enabling rapid reactor start-up.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- 宁夏中科国通新能源有限公司
- Filing Date
- 2025-12-30
- Publication Date
- 2026-05-05
AI Technical Summary
Traditional nitrification-denitrification processes for treating landfill leachate involve large carbon source additions, high energy consumption, large sludge production, and low nitrogen removal efficiency. Furthermore, anaerobic ammonia oxidizing bacteria are sensitive to the environment, have a slow growth rate, and require long reactor start-up times.
A carrier for anaerobic ammonia oxidation bacteria, comprising a nutrient core ball, a slow-release regulation layer, and an attachment layer, was designed to shorten the start-up time of the anaerobic ammonia oxidation reactor by providing continuous nutrition and a stable environment.
Nutrients are provided by the nutrient core sphere, the slow-release control layer regulates the nutrient release rate, and the attachment layer provides attachment sites, which significantly shortens the start-up time of the anaerobic ammonia oxidation reactor.
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Abstract
Description
Technical Field
[0001] This application relates to the field of waste treatment technology, and in particular to an anaerobic ammonia-oxidizing bacteria carrier for treating ammonia nitrogen in landfill leachate, its preparation method, and a reactor. Background Technology
[0002] Landfill leachate is a complex wastewater with high pollutant concentrations, characterized by high ammonia nitrogen concentrations, low C / N ratios, and the presence of large amounts of toxic and harmful substances. Traditional nitrification-denitrification processes for treating this type of wastewater suffer from problems such as large carbon source dosages, high energy consumption, large sludge production, and limited nitrogen removal efficiency.
[0003] Anaerobic ammonia oxidation (AAO), as a novel biological nitrogen removal technology, offers a promising solution for treating landfill leachate due to its significant advantages, such as requiring no organic carbon source, low oxygen consumption, and low sludge production. However, AAO bacteria are highly sensitive to environmental conditions, have a slow growth rate, and a generation cycle of 10–15 days, while ordinary heterotrophic bacteria only take a few hours. Therefore, the start-up time for AAO reactors under ambient temperature conditions is generally 3–6 months. Summary of the Invention
[0004] In view of this, this application proposes an anaerobic ammonia oxidation bacteria carrier for the treatment of ammonia nitrogen in landfill leachate, which can shorten the start-up time of the anaerobic ammonia oxidation reactor.
[0005] This application also proposes a method for preparing an anaerobic ammonia-oxidizing bacteria carrier for treating ammonia nitrogen in landfill leachate.
[0006] This application also proposes a reactor containing a carrier of anaerobic ammonia-oxidizing bacteria for the treatment of ammonia nitrogen in landfill leachate.
[0007] An anaerobic ammonia-oxidizing bacteria carrier for landfill leachate ammonia nitrogen treatment comprises, from the inside out: The nutrient core ball is used to provide nitrogen precursors and trace elements required for the growth of anaerobic ammonia-oxidizing bacteria; The slow-release regulating layer is used to control the release rate of the nutrient core spheres, so as to avoid excessive local nutrient concentration that inhibits the growth of anaerobic ammonia-oxidizing bacteria. The attachment layer provides attachment sites for anaerobic ammonia oxidizing bacteria, enabling them to secrete extracellular polymers and form biofilms.
[0008] A method for preparing an anaerobic ammonia-oxidizing bacteria carrier for landfill leachate ammonia nitrogen treatment includes the following steps: Step 1: Mix the nutrient solution, activated carbon, calcium carbonate, and binder, knead and extrude them into balls, and dry them to obtain nutrient core balls; Step 2: Immerse the nutrient core spheres in a mixed solution of chitosan and sodium alginate, then remove and immerse them in Ca... 2+Cross-linking in solution forms a sustained-release regulating layer; Step 3: Embed the nutrient core ball encapsulating the slow-release regulation layer into the pores of the polyurethane sponge, and fix it by hot pressing to obtain the anaerobic ammonia-oxidizing bacteria carrier.
[0009] An anaerobic ammonia oxidation reactor for treating ammonia nitrogen in landfill leachate includes an anaerobic ammonia oxidizing bacteria carrier.
[0010] The technical advantages of this application are as follows: the anaerobic ammonia oxidizing bacteria carrier of this application provides nutrients through a nutrient core ball, regulates the release rate of the nutrient core microsphere through a slow-release control layer, and provides attachment sites through an attachment layer. This provides continuous nutrition and a stable nutrient environment for anaerobic ammonia oxidizing bacteria, thereby improving their activity and growth rate, and thus shortening the start-up time of the anaerobic ammonia oxidation reactor.
[0011] In the early stage of reactor start-up, the colonization rate of anaerobic ammonia oxidizing bacteria is low. The nutrient core ball in the carrier of this application can provide targeted nutrition to attract anaerobic ammonia oxidizing bacteria to colonize on the carrier surface, thereby shortening the start-up time of the anaerobic ammonia oxidation reactor. Detailed Implementation
[0012] The embodiments of the technical solution of this application will be described in detail below. The following embodiments are only used to illustrate the technical solution of this application more clearly, and are therefore only examples, and should not be used to limit the scope of protection of this application.
[0013] An anaerobic ammonia-oxidizing bacteria carrier for landfill leachate ammonia nitrogen treatment comprises, from the inside out: The nutrient core ball is used to provide nitrogen precursors and trace elements required for the growth of anaerobic ammonia-oxidizing bacteria; The slow-release regulating layer is used to control the release rate of the nutrient core spheres, so as to avoid excessive local nutrient concentration that inhibits the growth of anaerobic ammonia-oxidizing bacteria. The attachment layer provides attachment sites for anaerobic ammonia oxidizing bacteria, enabling them to secrete extracellular polymers and form biofilms.
[0014] In a preferred embodiment, ammonium salts and nitrites are nitrogen source precursors for anaerobic ammonia oxidizing bacteria, and the nitrogen source precursors need to meet the requirements of anaerobic ammonia oxidizing bacteria for NH4+. + and NO2 － There are two different requirements, and the required amounts of the two ions are different. The ratio of ammonium salt to nitrite is based on NH4+. ＋ NO2 － The mixture is prepared with a molar ratio of 1:(1.3~1.4).
[0015] In a preferred embodiment, the trace element is selected from one or more of Fe, Co, and Ni. The trace element exists in the form of a soluble salt, such as FeSO4, CoCl2, or NiCl2.
[0016] In a preferred embodiment, the nutrient core ball comprises activated carbon, nutrient salts, calcium carbonate, and a binder, wherein the nutrient salts contain nitrogen source precursors and trace elements.
[0017] Nutrients are adsorbed within the activated carbon. Calcium carbonate, being largely insoluble in water, acts as a sealant for the pores of the activated carbon. A binder binds the activated carbon and calcium carbonate together. Thus, when the anaerobic ammonia-oxidizing bacteria carrier is placed in water, the water, after passing through the slow-release regulating layer and contacting the nutrient core spheres, can only slowly penetrate the nutrient core spheres, carrying away the nutrients within, thereby achieving a slow-release effect.
[0018] In a preferred embodiment, the particle size of the nutrient core sphere is 5-10 mm.
[0019] In a preferred embodiment, the sustained-release regulating layer comprises chitosan, sodium alginate, and calcium alginate, wherein the chitosan, sodium alginate, and calcium alginate form a gel layer rich in micropores.
[0020] The pore size of the sustained-release control layer is determined according to the release rates of urea and nitrite. In a preferred embodiment, the pore size of the sustained-release control layer is 0.1–0.5 μm. The pore size of the sustained-release control layer is adjusted by adding Ca. 2+ The pore size depends on the concentration of calcium ions; the higher the concentration, the smaller the pore size. After the anaerobic ammonia oxidizing bacteria carrier is placed in water, the water needs to contact the nutrient core sphere through the small pores of the slow-release control layer. Initially, the number of anaerobic ammonia oxidizing bacteria is also relatively small, and the release of nutrients is also relatively small, which is compatible with each other. As water seeps in, the release rate of nutrients becomes relatively faster. At the same time, the number of anaerobic ammonia oxidizing bacteria also increases, and the release rate of nutrients from the nutrient core sphere of this application can match the number of anaerobic ammonia oxidizing bacteria. The outflow of nutrients in this application is essentially the diffusion of ions from high concentration to low concentration. Due to the small pore size of the slow-release control layer, water seepage is slow. After entering the nutrient core sphere, the water seepage is still slow due to the obstruction of calcium carbonate, which can effectively delay the release of nutrients, allowing nutrients to be released continuously for 15-30 days, thereby accelerating the growth and reproduction of anaerobic ammonia oxidizing bacteria and significantly shortening the start-up time of the anaerobic ammonia oxidation reactor.
[0021] In a preferred embodiment, the adhesion layer is a polyurethane foam.
[0022] Polyurethane foam has abundant pores, providing ample attachment sites for anaerobic ammonia oxidizing bacteria. Simultaneously, the relatively enclosed space within the pores provides a favorable anaerobic environment for these bacteria, facilitating their growth and reproduction.
[0023] In a preferred embodiment, the diameter of the anaerobic ammonia-oxidizing bacteria carrier is 1 to 3 cm.
[0024] A method for preparing an anaerobic ammonia-oxidizing bacteria carrier for landfill leachate ammonia nitrogen treatment includes the following steps: Step 1: Mix the nutrient solution, activated carbon, calcium carbonate, and binder, knead and extrude them into balls, and dry them to obtain nutrient core balls; Step 2: Immerse the nutrient core spheres in a mixed solution of chitosan and sodium alginate, then remove and immerse them in Ca... 2+ Cross-linking in solution forms a sustained-release regulating layer; Step 3: Embed the nutrient core ball encapsulating the slow-release regulation layer into the pores of the polyurethane sponge, and fix it by hot pressing to obtain the anaerobic ammonia-oxidizing bacteria carrier.
[0025] In a preferred embodiment, Ca 2+ The solution is a CaCl2 solution. Besides this, other soluble Ca... 2+ Salt solutions can also be used for cross-linking of sodium alginate.
[0026] In a preferred embodiment, the concentration of the CaCl2 solution is 15-25 g / L, and the immersion time in the CaCl2 solution is 5-10 min.
[0027] In a preferred embodiment, the mixed solution of chitosan and sodium alginate contains a predetermined concentration of soluble salt, the composition of which is the same as that of the nutrient solution. This reduces or prevents the loss of nutrients when the nutrient core spheres are immersed in the mixed solution. 2+ The same applies to solutions. The concentration of soluble salts depends on actual needs and is generally no greater than the concentration of the corresponding component in the nutrient solution.
[0028] In a preferred embodiment, the preparation steps of the nutrient core spheres are as follows: Step 11: Add ammonium salt, nitrite, and trace element salt to water according to the predetermined concentration and stir to prepare a nutrient solution; Step 12: Add binder to nutrient solution and stir evenly to form a mixture with a certain viscosity; at the same time, mix activated carbon and calcium carbonate evenly according to a predetermined mass ratio to form a mixed powder; Step 13: Mix the liquid and powder together and continue stirring and kneading until it becomes a dough; Step 14: Extrude the mixed mud into balls using an extruder, and dry them to obtain nutrient core balls.
[0029] In a preferred embodiment, the binder is β-cyclodextrin. β-cyclodextrin has low solubility in water, exhibits a certain sustained-release effect, and also has good adhesion and curing capabilities.
[0030] In a preferred embodiment, the mass ratio of activated carbon, calcium carbonate, and β-cyclodextrin is (45-55):(35-45):(10-20).
[0031] In a preferred embodiment, the ammonium salt is ammonium chloride, with a concentration of 120–160 mg / L in the nutrient solution; the nitrite is sodium nitrite, with a concentration of 200–288 mg / L in the nutrient solution. Anaerobic ammonia-oxidizing bacteria react with NH4+. + and NO2 － The concentration requirement is relatively high; too high a concentration will inhibit its growth and reproduction.
[0032] In a preferred embodiment, the trace element is one or more of FeSO4, CoCl2, and NiCl2. The concentration of FeSO4 in the nutrient solution is 15-25 mg / L; the concentration of CoCl2 in the nutrient solution is 15-25 mg / L; and the concentration of NiCl2 in the nutrient solution is 15-25 mg / L.
[0033] In a preferred embodiment, the concentration of chitosan is 5-8 g / L and the concentration of sodium alginate is 15-25 g / L.
[0034] In a preferred embodiment, the nutrient core spheres are immersed in a mixed solution of chitosan and sodium alginate for 15 to 20 minutes.
[0035] An anaerobic ammonia oxidation reactor for treating ammonia nitrogen in landfill leachate includes an anaerobic ammonia oxidizing bacteria carrier.
[0036] Other components of the anaerobic ammonia oxidation reactor include at least a shell containing anaerobic ammonia-oxidizing bacteria carriers, an inlet for the water to be treated, and an outlet for the water to flow through. As the water flows through, it is intercepted by the anaerobic ammonia-oxidizing bacteria carriers, thereby removing ammonia nitrogen from the water.
[0037] The following is a detailed process for preparing the anaerobic ammonia oxidizing bacteria carrier in this application. To illustrate the effect of this application, a comparative example is also provided below. The anaerobic ammonia oxidizing bacteria carriers prepared in the examples and comparative examples are placed in an anaerobic ammonia oxidation reactor and connected to a wastewater treatment system to compare the start-up time of the anaerobic ammonia oxidation reactor.
[0038] Example 1 Nutrient solution: ammonium chloride 120 mg / L, sodium nitrite 200 mg / L, ferrous sulfate 15 mg / L; β-Cyclodextrin was added to the nutrient solution and stirred continuously until a stable solid-liquid suspension was formed. Simultaneously, activated carbon and calcium carbonate were dry-mixed in a high-speed mixer to obtain a mixed powder. The solid-liquid suspension and mixed powder were then stirred in a kneader to form a mud ball, with a mass ratio of activated carbon, calcium carbonate, and β-cyclodextrin of 45:35:20. The mud ball was placed in a roller extruder to form spheres with a diameter of 10 mm, which were then air-dried to obtain nutrient core balls. The nutrient core balls were immersed in a mixed solution of chitosan (5 g / L) and sodium alginate (15 g / L) for 15 minutes, then removed and immersed in a 15 g / L calcium chloride solution for 5 minutes to form a slow-release regulating layer on the surface of the nutrient core balls. The nutrient core balls coated with the slow-release regulating layer were embedded in the pores of a polyurethane sponge and fixed by hot pressing to obtain an anaerobic ammonia-oxidizing bacteria carrier with a diameter of 2 cm.
[0039] Comparative Example 1 The difference between Comparative Example 1 and Example 1 is that the nutrient solution was replaced with water.
[0040] Comparative Example 2 The difference between Comparative Example 2 and Example 1 is that there is no sustained-release control layer.
[0041] Comparative Example 3 The difference between Comparative Example 3 and Example 1 is that the nutrient core sphere does not contain calcium carbonate.
[0042] The anaerobic ammonia-oxidizing bacteria carriers prepared in Example 1 and Comparative Examples 1, 2, and 3 were placed into four anaerobic ammonia oxidation reactors, respectively. The anaerobic ammonia oxidation reactors were connected to the effluent outlets of the nitrification reactors in the wastewater treatment system, allowing the wastewater treated by the nitrification reactors to flow through the anaerobic ammonia oxidation reactors, thus enabling the anaerobic ammonia-oxidizing bacteria on the carriers to grow and multiply. After labeling, the anaerobic ammonia oxidation reactors were tested every week for one month. First, the NH4 content at the effluent outlet of the ammonia oxidation reactor was measured. ＋ NO2 － After the concentration of NH4+ reaches the standard, the abundance of anaerobic ammonia oxidizing bacteria on the carrier is tested. After reaching the standard, the stability and shock resistance of the anaerobic ammonia oxidation reactor are tested. When all three indicators meet the standards, it indicates that the anaerobic ammonia oxidation reactor is ready for start-up. The test results are shown in Table 1. For simplicity, NH4+... ＋ NO2 － The concentration of anaerobic ammonia oxidizing bacteria is index 1, the abundance of anaerobic ammonia oxidizing bacteria is index 2, and the stability and shock resistance of the anaerobic ammonia oxidation reactor is index 3. Table 1 As can be seen from Table 1, in the first week after one month, the treated wastewater in Example 1 contained NH4+. ＋ NO2 －The concentration of anaerobic ammonia oxidizing bacteria on the carrier reached the standard by the third week after one month; and by the fourth week after one month, the stability and shock resistance of the anaerobic ammonia oxidizing reactor reached the standard, meeting the start-up conditions. In contrast, in Comparative Examples 1, 2, and 3, the reactors did not meet the start-up conditions until the fifth week. This demonstrates that the anaerobic ammonia oxidizing bacteria carrier of this application can significantly shorten the reactor start-up time. Furthermore, by adding calcium carbonate to the nutrient core spheres and setting a slow-release layer on the surface of the nutrient core spheres, a good slow-release effect can be achieved, continuously providing nutrients for the anaerobic ammonia oxidizing bacteria.
[0043] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.
Claims
1. An anaerobic ammonia-oxidizing bacteria carrier for treating ammonia nitrogen in landfill leachate, characterized in that: From the inside out, it includes: The nutrient core ball is used to provide nitrogen precursors and trace elements required for the growth of anaerobic ammonia-oxidizing bacteria; The slow-release regulating layer is used to control the release rate of the nutrient core spheres, so as to avoid excessive local nutrient concentration that inhibits the growth of anaerobic ammonia-oxidizing bacteria. The attachment layer provides attachment sites for anaerobic ammonia oxidizing bacteria, enabling them to secrete extracellular polymers and form biofilms.
2. The anaerobic ammonia-oxidizing bacteria carrier for landfill leachate ammonia nitrogen treatment as described in claim 1, characterized in that: The nutrient core ball is composed of activated carbon, nutrient salts, calcium carbonate, and binder. The nutrient salts contain nitrogen source precursors and trace elements.
3. The anaerobic ammonia-oxidizing bacteria carrier for landfill leachate ammonia nitrogen treatment as described in claim 1, characterized in that: The sustained-release regulating layer comprises chitosan, sodium alginate, and calcium alginate, which together form a microporous gel layer.
4. The anaerobic ammonia-oxidizing bacteria carrier for landfill leachate ammonia nitrogen treatment as described in claim 1, characterized in that: The adhesive layer is a polyurethane foam.
5. The method for preparing the anaerobic ammonia-oxidizing bacteria carrier for landfill leachate ammonia nitrogen treatment as described in claim 1, characterized in that... Includes the following steps: Step 1: Mix the nutrient solution, activated carbon, calcium carbonate, and binder, knead and extrude them into balls, and dry them to obtain nutrient core balls; Step 2: Immerse the nutrient core spheres in a mixed solution of chitosan and sodium alginate, then remove and immerse them in Ca... 2+ Cross-linking in solution forms a sustained-release regulating layer; Step 3: Embed the nutrient core ball encapsulating the slow-release regulation layer into the pores of the polyurethane sponge, and fix it by hot pressing to obtain the anaerobic ammonia-oxidizing bacteria carrier.
6. The preparation method according to claim 5, characterized in that: The mixed solution of chitosan and sodium alginate contains a predetermined concentration of soluble salts, the composition of which is the same as that of the nutrient solution.
7. The preparation method according to claim 5, characterized in that: The preparation steps of the nutrient core spheres are as follows: Step 11: Add ammonium salt, nitrite, and trace element salt to water according to the predetermined concentration and stir to prepare a nutrient solution; Step 12: Add binder to nutrient solution and stir evenly to form a mixture with a certain viscosity; at the same time, mix activated carbon and calcium carbonate evenly according to a predetermined mass ratio to form a mixed powder; Step 13: Mix the liquid and powder together and continue stirring and kneading until it becomes a dough; Step 14: Extrude the mixed mud into balls using an extruder, and dry them to obtain nutrient core balls.
8. The preparation method according to claim 7, characterized in that: The binder is β-cyclodextrin.
9. The preparation method according to claim 8, characterized in that: The mass ratio of activated carbon, calcium carbonate, and β-cyclodextrin is (45-55):(35-45):(10-20).
10. An anaerobic ammonia oxidation reactor for treating ammonia nitrogen in landfill leachate, characterized in that: Includes the anaerobic ammonia-oxidizing bacteria carrier as described in any one of claims 1 to 4.