Active sludge containing biological manganese oxide, preparation method and application thereof, and treatment method of nitrogen-containing wastewater

Abstract

The invention discloses a preparation method of activated sludge containing biological manganese oxide and a nitrogen-containing wastewater treatment method. The preparation method comprises the following steps: S1, inoculating activated sludge into an ammonia nitrogen solution; s2, manganese-humic acid chelate is added into the mixture obtained in the step S1 for culture, and the activated sludge containing the biological manganese oxide is obtained, wherein the mass ratio of the manganese-humic acid chelate to the activated sludge to the ammonia nitrogen solution is (20-50): (450-550): (180-220). According to the present invention, humic acid HA simultaneously has oxidation (quinone group-containing) and reduction (phenol group-containing) capabilities of electron absorption and electron supply, humic acid HA is adopted as a chelating agent to prepare a manganese-humic acid chelate Mn-HA, and the manganese-humic acid chelate Mn-HA is cultured in active sludge to generate the biological manganese oxide BioMnOx; when nitrogen-containing wastewater is treated, the substance not only can oxidize NH4 < + >-N to generate NO3 <->-N and NO2 <->-N under the action of microorganisms, but also can reduce the NO3 <->-N and NO2 <->-N into N2 by virtue of low-valence manganese obtained by reduction under the action of microorganisms, so that complete removal of nitrogen is realized.

Description

Technical Field

[0001] The present application relates to the field of nitrogen-containing wastewater treatment, and more specifically to an activated sludge containing biological manganese oxides, a preparation method and application thereof, and a method for treating nitrogen-containing wastewater. Background Art

[0002] Due to human activities, such as the abuse of fertilizers and the discharge of industrial wastewater, nitrogen is overloaded in water bodies. Excessive inorganic nitrogen in drinking water is harmful to humans and livestock, leading to eutrophication of water bodies, accelerating the degradation of rivers and lakes, and reducing drinkable freshwater resources. For the removal of inorganic nitrogen from water bodies, biological methods have the advantages of low cost and environmental friendliness. Traditional biological methods include nitrification and denitrification, which require O 2 The addition of an organic carbon source means that more energy is required. Excessive production of residual sludge and greenhouse gas emissions are also huge challenges faced by traditional biological methods in treating ammonia-containing wastewater.

[0003] Research in the past decade has revealed the diversity of ammonia conversion microorganisms, which is of great significance for overcoming the above-mentioned shortcomings of traditional biological methods. 2 Anaerobic ammonium oxidation (ANAMMOX) has been widely studied due to its advantages such as low production of waste sludge and carbon source, and no greenhouse gas emissions. However, its high sensitivity to environmental conditions limits its large-scale application. To date, transition metal redox-mediated anaerobic nitrogen transformation (MRMNT) has been proposed to replace ANAMMOX.

[0004] MRMNT can be defined as a combination of two steps, i) transition metal oxide reduction coupled with ammonia oxidation, where ammonia is converted to nitrate or nitrite (Mnammox), and ii) low-valent transition metal oxidation coupled with nitrate / nitrite reduction to nitrogen gas (NDMO). Transition metal oxides, mainly MnO x (Manganese oxide) and FeOx (Iron oxide) are potential oxidants of ammonia in anaerobic environment. 2 ﹥NO 3 - ﹥MnO x ﹥FeO x , MnO x FeO x It can also convert ammonia into N 2 , NO 2 - and NO 3 - (Mnammox). In addition, low-valent iron has the ability to over-reduce nitrate / nitrite to ammonia, which leads to low denitrification efficiency. Therefore, manganese is a more excellent transition metal for regulating nitrogen conversion.

[0005] Therefore, technicians in this field are committed to developing a manganese-based denitrification material that is low-cost, environmentally friendly, has a simple production process, high denitrification efficiency, and can completely remove pollutants. Summary of the invention

[0006] In MnO x In the anaerobic nitrogen transformation process mediated by natural MnO x Usually exists in the form of insoluble solid phase minerals, which leads to MnO x The contact area between MnO and microorganisms is limited, thus limiting the reaction rate. x Due to the solubility and reactivity of MnO, it is necessary to use some molecules or ions for chelation to increase the x The contact area with microorganisms can be increased, thereby improving the reaction efficiency. Humic acid (HA), as a naturally occurring organic molecule (Natural Organic Matter, NOM), is widely used in the fields of electron shuttle and metal chelation due to its rich functional group structure. This application uses HA as a chelating agent to prepare manganese-humic acid chelate (Manganese-Humic Acid Complex, Mn-HA). The rationality of this choice is that humic acid HA can not only effectively chelate MnO x , significantly improving its solubility and reactivity, and due to its rich functional group structure, it can enhance the x The electron transfer process between manganese and microorganisms. These characteristics enable Mn-HA to promote anaerobic nitrogen conversion reactions more efficiently. In addition, the formation of manganese-humic acid chelated manganese (Mn-HA) also has important environmental advantages, which can reduce the mobility of manganese and reduce its toxicity, thereby reducing its potential threat to the ecosystem. These characteristics make Mn-HA more stable and efficient in the anaerobic nitrogen conversion process.

[0007] In a first aspect, the present application provides a method for preparing activated sludge containing biological manganese oxides, comprising:

[0008] S1. Inoculate the activated sludge into the ammonia nitrogen solution;

[0009] S2, adding manganese-humic acid chelate Mn-HA to step S1 for culturing to obtain the activated sludge containing biological manganese oxides;

[0010] Among them, the mass ratio of manganese-humic acid chelate Mn-HA: activated sludge: ammonia nitrogen solution is 20-50: 450-550: 180-220.

[0011] Preferably, in the ammonia nitrogen solution, dissolved oxygen <0.5 mg / L, ammonia nitrogen NH 4 + -N concentration is 30-60 mg / L.

[0012] Preferably, the culture conditions in step S2 are: sealed culture in the dark at 25-35° C. for 1-12 months.

[0013] Preferably, the manganese-humic acid chelate Mn-HA is prepared by the following method:

[0014] S21, adding humic acid HA to manganese chloride tetrahydrate solution to obtain a mixed solution, wherein the mass ratio of manganese chloride tetrahydrate: distilled water: humic acid HA is 350-450:1000:40-60;

[0015] S22, adjusting the pH of the mixed solution in step S21 to 6-8, stirring and centrifuging to obtain a precipitate;

[0016] S23, washing, drying, grinding and sieving the precipitate obtained in step S22 to obtain the manganese-humic acid chelate Mn-HA.

[0017] Preferably, step S23 specifically comprises: washing the precipitate obtained in step S22 with distilled water and centrifugally filtering it, drying it at 50-60° C., grinding it, and sieving it through a 10-200 mesh sieve.

[0018] In a second aspect, the present application provides an activated sludge containing biological manganese oxides, which is prepared by the above preparation method.

[0019] In a third aspect, the present application provides the use of activated sludge containing biological manganese oxides in treating nitrogen-containing wastewater.

[0020] In a fourth aspect, the present application provides a method for treating nitrogen-containing wastewater, comprising:

[0021] The nitrogen-containing wastewater is introduced into the activated sludge containing biological manganese oxides or the activated sludge containing biological manganese oxides prepared by the above preparation method, wherein the mass ratio of the nitrogen-containing wastewater to the activated sludge containing biological manganese oxides is 4-100:1.

[0022] Preferably, the inorganic nitrogen in the nitrogen-containing wastewater is ammonia nitrogen, nitric nitrogen or a mixture of ammonia nitrogen and nitric nitrogen.

[0023] Among them, when the inorganic nitrogen in the nitrogen-containing wastewater is a mixture of ammonia nitrogen and nitric nitrogen, if the molar concentration ratio of ammonia nitrogen to nitric nitrogen is less than 5:3, low-valent manganese substances are added to achieve a molar concentration of ammonia nitrogen and nitric nitrogen of 5:3; if the molar concentration ratio of ammonia nitrogen to nitric nitrogen is greater than 5:3, high-valent manganese substances are added to achieve a molar concentration of ammonia nitrogen and nitric nitrogen of 5:3.

[0024] Preferably, the method for treating the nitrogen-containing wastewater adopts a continuous or intermittent water inflow method, and the hydraulic retention time is ≥ 6h.

[0025] The technical solution of this application achieves the following technical effects:

[0026] 1. The present application utilizes humic acid HA, which has the ability to absorb and supply electrons for oxidation (containing quinone groups) and reduction (containing phenol groups), and uses it as a chelating agent to prepare a manganese-humic acid chelate Mn-HA. The manganese-humic acid chelate Mn-HA is cultured in activated sludge to generate biological manganese oxide BioMnO x BioMnO in the treatment of nitrogen-containing wastewater x Under the action of microorganisms, it can not only oxidize NH 4 + -N Generate NO 3 - -N and NO 2 - -N, and the reduced low-valent manganese can convert NO 3 - -N and NO 2 - -N Restore to N 2 , achieving complete removal of nitrogen.

[0027] 2. Humic acid HA has a large number of functional groups. The manganese-humic acid chelate Mn-HA obtained by chelating manganese can greatly reduce the toxic effect of simple manganese oxides on microorganisms (even directly kill microorganisms), thereby reducing the potential threat to the ecosystem.

[0028] 3. The nitrogen-containing wastewater treatment method of the present application does not require additional addition of O 2 and carbon source, with low residual sludge production and no greenhouse gas emissions.

[0029] The concept, specific structure and technical effects of the present application will be further described below in conjunction with the accompanying drawings to fully understand the purpose, characteristics and effects of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is a SEM image of the manganese-humic acid chelate Mn-HA in Example 1 of the present application, which shows that the manganese-humic acid chelate Mn-HA particles are aggregated together.

[0031] Figure 2 This is another SEM image of the manganese-humic acid chelate Mn-HA in Example 1 of the present application, which shows that the manganese-humic acid chelate Mn-HA presents an uneven crystal state.

[0032] Figure 3 The biomanganese oxide BioMnO in Example 2 of this application x SEM image of .

[0033] Figure 4 The biomanganese oxide BioMnO in Example 2 of this application x Another SEM image of the biomanganese oxide BioMnO x Wrapped in fiber.

[0034] Figure 5 The manganese-humic acid chelate Mn-HA obtained in Example 1 of the present application and the biological manganese oxide BioMnO obtained in Example 2 x Comparison chart of element contents in .

[0035] Figure 6 The manganese-humic acid chelate Mn-HA obtained in Example 1 and the biological manganese oxide BioMnO obtained in Example 2 x TIR comparison chart.

[0036] Figure 7 The manganese-humic acid chelate Mn-HA obtained in Example 1 and the biological manganese oxide BioMnO obtained in Example 2 x XRD comparison chart of .

[0037] Figure 8 The biomanganese oxide BioMnO is generated during the sludge cultivation process of Example 2 of the present application. x Content comparison chart.

[0038] Fig. 9 The activated sludge containing biological manganese oxide in Example 2 of the present application and the comparative sludge in the comparative example have a significant effect on NO 3 - -N removal effect diagram.

[0039] Fig.10 The activated sludge containing biological manganese oxide in Example 2 of the present application and the comparative sludge in the comparative example have a significant effect on NH 4 + -N removal effect diagram. DETAILED DESCRIPTION

[0040] The following describes the embodiments of the present application through specific examples, and those skilled in the art can easily understand other advantages and effects of the present application from the contents disclosed in this specification. The present application can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present application. It should be noted that the following embodiments and features in the embodiments can be combined with each other without conflict.

[0041] Some exemplary embodiments of the present application are described for the purpose of explanation, and it should be understood that the present application may be implemented in other ways not specifically shown in the drawings.

[0042] In one aspect, the present application discloses a method for preparing activated sludge containing biological manganese oxides, comprising the following steps:

[0043] S1. Inoculate the activated sludge into the ammonia nitrogen solution;

[0044] S2, adding manganese-humic acid chelate Mn-HA to step S1 for culturing to obtain activated sludge containing biological manganese oxides;

[0045] Wherein, the mass ratio of manganese-humic acid chelate Mn-HA:activated sludge:ammonia nitrogen solution is 20-50:450-550:180-220, preferably 25:500:200.

[0046] The activated sludge involved in step S1 is taken from the secondary sedimentation tank of the sewage treatment plant.

[0047] The ammonia nitrogen solution in step S1 refers to an aqueous solution containing ammonia nitrogen, which can be prepared by itself. Specifically, the ammonia nitrogen solution in this application can be prepared using tap water and nitrogen (N 2 ) The dissolved oxygen (DO) obtained by aeration treatment is <0.5mg / L, and contains 30-60mg / L ammonia nitrogen (NH 4 + -N) aqueous solution. When the ammonia nitrogen concentration is too low, it will not be able to meet the nutritional needs of microorganisms, resulting in limited microbial growth, especially nitrifying bacteria need sufficient ammonia nitrogen as their energy and growth source; when the ammonia nitrogen concentration is too high (for example, higher than 60 mg / L), free ammonia (NH 3 ) concentration increases, which is highly toxic to bacteria and inhibits their activity and proliferation. 4 + -N) concentration is controlled at 30-60 mg / L.

[0048] The activated sludge containing biological manganese oxide in step S2 refers to the manganese-humic acid chelate Mn-HA that is cultured in the activated sludge to generate biological manganese oxide BioMnO x The final product is enriched with specific microorganisms and contains biomanganese oxide BioMnO x The specific culture conditions in step S2 are: sealed culture at 25-35° C. in the dark for 1-12 months.

[0049] The manganese-humic acid chelate Mn-HA in this application can be directly purchased or prepared. The specific preparation method is as follows:

[0050] S21, adding humic acid HA to manganese chloride tetrahydrate solution to obtain a mixed solution, wherein the mass ratio of manganese chloride tetrahydrate: distilled water: humic acid HA is 350-450:1000:40-60, preferably 396:1000:50;

[0051] S22, adjusting the pH of the mixed solution in step S21 to 6-8, stirring and centrifuging to obtain a colloid;

[0052] S23, washing, drying, grinding and sieving the colloid obtained in step S22 to obtain manganese-humic acid chelate Mn-HA.

[0053] The purpose of step S21 is to obtain 2+ Therefore, manganese chloride tetrahydrate, manganese sulfate (MnSO 4 ), manganese carbonate (MnCO 3 ) can provide Mn 2+ In this application, manganese chloride tetrahydrate is preferably used, and the mass ratio of manganese chloride tetrahydrate: distilled water: humic acid HA is preferably 396:1000:50. Of course, manganese chloride tetrahydrate can be replaced by an equimolar manganese sulfate (MnSO 4 ), manganese carbonate (MnCO 3 ) etc. containing Mn 2+ Humic acid HA can be directly purchased. The humic acid HA used in this application comes from Shanghai Yuanye Biotechnology Co., Ltd.: Detailed information - Humic acid (brand: Yuanye, item number: S24634); purchase link - [https: / / www.biomart.cn / infosupply / 82603484.htm].

[0054] In step S22, a common base (e.g., NaOH, KOH, NaHCO 3 、Na 2 CO 3 etc.) and common acids (e.g. HCl, HNO 3, H 2 SO 4 etc.) to adjust the pH to 6-8, preferably 7; during the process of adjusting the pH, precipitation will be generated. The reasons for selecting this pH range are as follows: Humic acid HA contains multiple functional groups (such as carboxyl, phenolic hydroxyl, etc.), and the dissociation equilibrium of these functional groups is affected by the pH value. Under neutral to weakly alkaline conditions, carboxyl and other groups partially dissociate to form negative charges, which increase the coordination ability with metal ions; within the pH range of 6.0-8.0, the carboxyl and phenolic hydroxyl groups in humic acid HA are in the best dissociation state, which is conducive to forming a stable chelate with manganese ions; the solubility and form of manganese ions are affected by the pH value. Within this pH range, manganese ions are in the form of soluble divalent manganese (Mn 2+ ) form, which is convenient for forming a chelate with humic acid HA. After adjusting the pH, the present application is stirred for about 12 hours, then centrifuged for 10 minutes (for example, at a speed of 12000 rpm), and filtered to obtain a black colloid.

[0055] In step S23, the cleaning is specifically to rinse the obtained black colloid with distilled water and filter after centrifugation for 10 minutes (for example, at a speed of 12000rpm), and repeat the cleaning step three times to remove impurities. Drying is specifically drying at 50-60°C. Sieving is specifically sieving the dried material through a 10-200 mesh sieve to obtain a black powdery manganese-humic acid chelate Mn-HA. The sieving operation obtains particles with uniform and smaller particle sizes (particle size range is approximately 0.074mm-2mm), which can increase the specific surface area of ​​the manganese-humic acid chelate Mn-HA, thereby increasing the contact area with microorganisms and improving the degradation and adsorption efficiency of microorganisms. In addition, when the manganese-humic acid chelate Mn-HA of this particle size is co-cultured with microorganisms, it can be captured and embedded by microbial extracellular secretion substances (such as EPS) under certain conditions due to its surface characteristics and microbial activity. The smaller the particle size, the better. Extremely small particles (for example, those sieved through a sieve larger than 200 mesh) may enter the cells or pass through the pores of bacterial membranes, causing oxidative stress or chemical toxicity.

[0056] On the other hand, the present application also provides an activated sludge containing biological manganese oxides, which is prepared by the preparation method as described above. The activated sludge containing biological manganese oxides can achieve rapid conversion of inorganic nitrogen. The specific principle is described in detail in the treatment method of nitrogen-containing wastewater below.

[0057] On the other hand, the present application also provides a method for treating nitrogen-containing wastewater, comprising passing nitrogen-containing wastewater into the aforementioned biological manganese oxide-containing activated sludge, wherein the mass ratio of nitrogen-containing wastewater to biological manganese oxide-containing activated sludge is: 4-100:1, when the nitrogen content is high, the mass ratio of nitrogen-containing wastewater to biological manganese oxide-containing activated sludge can be lower, for example, 4:1, when the nitrogen content is low, the nitrogen-containing wastewater can be more, for example, up to 100:1. According to the requirements of the total inorganic nitrogen concentration of the drainage, the ratio of nitrogen-containing wastewater to biological manganese oxide-containing activated sludge, the treatment time of nitrogen-containing wastewater and other factors can be adjusted accordingly, and finally, as long as the wastewater meets the discharge standards, it can be discharged.

[0058] The treatment of nitrogen-containing wastewater can be carried out by continuous or intermittent water inflow, with a hydraulic retention time ≥ 6h. A longer hydraulic retention time can be set according to the requirements of the total inorganic nitrogen concentration in the discharged water.

[0059] The inorganic nitrogen in the nitrogen-containing wastewater can be ammonia nitrogen, nitric nitrogen or a mixture of the two, and the total inorganic nitrogen concentration is preferably not more than 60 mg / L. The treatment method of nitrogen-containing wastewater of the present application can achieve rapid conversion of inorganic nitrogen. The specific principle is as follows:

[0060] The present invention utilizes the ability of humic acid HA to absorb and supply electrons for oxidation (containing quinone groups) and reduction (containing phenol groups), and cultivates manganese-humic acid chelate Mn-HA in activated sludge to generate biological manganese oxide BioMnO x The activated sludge containing biological manganese oxide can achieve rapid conversion of inorganic nitrogen. x (The following reaction formula refers to the common representation in the art, expressed as MnO 2 ) Under the action of microorganisms, it can not only oxidize NH 4 + -N Generate NO 3 - -N and NO 2 - -N (Formula (1)-(3)), and the reduced low-valent manganese can convert NO 3 - -N and NO 2 - -N Restore to N 2 (Formula (1)-(3)), thereby achieving complete removal of nitrogen.

[0061]

[0062] Furthermore, in nitrogen-containing wastewater, when the molar concentration ratio of ammonia nitrogen to nitrate nitrogen is 5:3, the treatment effect is optimal, because high-valent manganese-mediated ammonia nitrogen and nitrate nitrogen directly generate N 2(See formula (6)-(7)). At this molar concentration ratio, manganese acts as an electron mediator and there is no direct loss (no consumption), so no additional addition is required:

[0063]

[0064] If the molar concentration ratio of ammonia nitrogen to nitric nitrogen is less than 5:3, a low-valent manganese substance (preferably a substance containing divalent manganese) is added, such as manganese-humic acid chelate Mn-HA, tetrahydrated manganese chloride, etc. The specific amount added can be calculated according to the equation for the reaction of nitric nitrogen and divalent manganese, so as to finally achieve a molar concentration of ammonia nitrogen and nitric nitrogen of 5:3, and calculate the amount of divalent manganese added. If the molar concentration ratio of ammonia nitrogen to nitric nitrogen is greater than 5:3, it indicates that ammonia nitrogen is in the majority, and more high-valent manganese is needed to react with it. At this time, it is necessary to add a high-valent manganese substance (containing high-valent manganese such as tetravalent manganese, hexavalent manganese, heptavalent manganese, etc.), and the biological manganese oxide-containing activated sludge in this application contains more high-valent manganese, so an appropriate amount of biological manganese oxide-containing activated sludge can be added to finally achieve a molar concentration of ammonia nitrogen and nitric nitrogen of 5:3.

[0065] In the above-mentioned treatment method for nitrogen-containing wastewater, it is preferred that the DO in the ammonia nitrogen wastewater is less than 0.5 mg / L (this can be achieved by nitrogen aeration), and the COD content is 60-120 mg / L, at which time no additional organic carbon source is required.

[0066] Example 1 Preparation of manganese-humic acid chelate Mn-HA

[0067] Dissolve 39.6g of manganese chloride tetrahydrate in 100ml of distilled water, then stir and dissolve to obtain a manganese chloride tetrahydrate solution, add 5g of humic acid HA to the aforementioned manganese chloride tetrahydrate solution, adjust the pH of the solution to 7, stir for 12 hours, then centrifuge at 12000rpm for 10 minutes, and filter to obtain a black colloidal substance. Rinse the obtained black colloidal substance with distilled water and filter after centrifugation at 12000rpm for 10min. Repeat this step three times to remove impurities. After drying the washed black colloidal substance at 50°C, grind it with an agate mortar, and sieve it through a 20-mesh sieve to finally obtain a black powdery substance, manganese-humic acid chelate Mn-HA. The SEM image of manganese-humic acid chelate Mn-HA is shown as follows. Figure 1-2 As shown in the figure, it can be seen that the manganese-humic acid chelate Mn-HA particles are agglomerated together (such as Figure 1 ), and presents an uneven crystal shape (as shown Figure 2 shown).

[0068] Example 2 Preparation of activated sludge containing biological manganese oxides

[0069] 25 g of Mn-HA prepared in Example 1, 500 g of activated sludge (MLVSS 3.5 g / L) and 200 ml of N 2 Aeration to DO less than 0.5mg / L containing 50mg / L NH 4 + -N deionized water, placed in a dark environment at a constant temperature (35°C), sealed and cultured for 6 months. 4 + After -N is exhausted, ammonia nitrogen is replenished in time, pH is maintained at 6.5-7.0, ORP-150±30mV, and finally activated sludge containing biological manganese oxides is obtained.

[0070] Take an appropriate amount of activated sludge containing biological manganese oxide, wash it three times with deionized water, and air-dry it at room temperature to obtain biological manganese oxide BioMnO x , its SEM picture is as follows Figure 3-4 As shown in the figure, it can be seen that biomanganese oxide BioMnO x The surface of the manganese-humic acid chelate Mn-HA in Example 1 is looser and rougher (e.g. Figure 1 ) and is wrapped by fibers (as shown Figure 4 As shown), it shows that biomanganese oxide BioMnO x The surface is more easily attached to microorganisms, and the "fibers" are traces of microbial growth. For example, the fiber may be the extracellular secretion substance EPS of the microorganism wrapped in the bio-manganese oxide BioMnO x Surface formation.

[0071] Figure 5 The manganese-humic acid chelate Mn-HA obtained in Example 1 and the biological manganese oxide BioMnO obtained in Example 2 x Comparison of element contents in BioMnO x The manganese content in the medium was lower than that in Mn-HA, indicating that Mn-HA was corroded during the sludge acclimation process.

[0072] Figure 6 The manganese-humic acid chelate Mn-HA obtained in Example 1 and the biological manganese oxide BioMnO obtained in Example 2 x TIR comparison chart. It can be seen from the figure that at 3430.66cm -1 The peak at 1615.12cm is the vibration of OH of phenolic hydroxyl group. The intensity of this absorption peak remains unchanged, indicating that the hydroxyl group represented by this peak does not participate in the biochemical process. -1 and 1384.7cm -1The peaks at 912.95cm represent the symmetric vibration and antisymmetric stretching of the carboxyl group, which come from HA. The peak intensity remains unchanged, indicating that HA may not be lost during the biochemical process; -1 and 798.48cm -1 The band represents the stretching of -CO-, which is produced by the adhesion of microorganisms to Mn-HA and the phenolic groups and aromatic ethers in the microbial secretions; BioMnO x The absorption peak is at 400-500cm -1 The absorption peak in this range corresponds to the lattice vibration of Mn-O, indicating that the biomanganese oxide BioMnO x The production of.

[0073] Figure 7 The manganese-humic acid chelate Mn-HA obtained in Example 1 and the biological manganese oxide BioMnO obtained in Example 2 x XRD comparison diagram. It can be seen from the figure that the peaks at 2θ = 12.320° and 24.966° correspond to K 0.27 MnO 2 (H 2 O) 0.54 At 2θ = 20.169° and 50.839°, MnCl 2 ·2H 2 The typical characteristic peaks of O. Compared with Mn-HA, the biomanganese oxide BioMnO x In K 0.27 MnO 2 (H 2 O) 0.54 and MnCl 2 ·2H 2 The degree of crystallinity in O is reduced, which is related to the crystal structure distortion caused by microbial corrosion.

[0074] In the implementation process of this embodiment, 10 mL of the homogenous mixture of sludge and water after sealed culture for one month, three months, and six months was taken into a 50 mL centrifuge tube, and then 10 mL of 0.04% triphenylmethane compound albumin blue (LBB) solution was added and placed in the dark for reaction for 8 minutes. The results are as follows: Figure 8 As shown in the figure, as the Mn-HA culture time increases, the blue color becomes darker, indicating that the longer the culture time, the higher the biomanganese oxide BioMnO x The more.

[0075] Preparation of comparative sludge (without using Mn-HA)

[0076] 500 g activated sludge (MLVSS 3.5 g / L) and 200 mL N 2 Aeration to DO less than 0.5mg / L containing 50mg / L NH 4 + -N deionized water, placed in a dark environment at a constant temperature (35°C), sealed and cultured for 6 months. 4 + After the -N is exhausted, ammonia nitrogen is replenished in time, pH is maintained at 6.5-7.0, ORP-150±30mV. The sludge obtained by this method is the control sludge.

[0077] Example 3 Treatment of nitrogen-containing wastewater (configuration wastewater)

[0078] 50 mL of the activated sludge containing biological manganese oxide in Example 2 and the comparative sludge in the comparative example were respectively mixed with 200 mL of deionized water (containing 10, 15, 20, 40, 60 mg / L of NO 3 - -N) was added to the serum bottle. The serum bottle was then sealed and placed in a constant temperature (35°C) and dark environment. Fig. 9 As shown in the figure, it can be seen that at different initial NO 3 - -N concentration, the denitrification rate constant K of the activated sludge containing biological manganese oxide in Example 2 is higher than that of the control sludge in the comparative example.

[0079] Example 4 Treatment of nitrogen-containing wastewater (configuration wastewater)

[0080] Take 50 mL of the activated sludge containing biological manganese oxide in Example 2 and the comparative sludge in the comparative example and 200 mL of deionized water (containing 10, 15, 20, 40, 60 mg / L NH 4 + -N) was added to the serum bottle, which was then sealed and placed in a constant temperature (35°C) dark environment. Fig.10 As shown in the figure, it can be seen that in different NH 4 + -N concentration, the activated sludge containing biological manganese oxide in Example 2 can convert NH 4 + -N is quickly removed, while the comparative sludge in Comparative Example 1 has almost no NH 4 + -N removal capacity, that is, the anaerobic environment cannot support NH 4 + -N oxidation, the biological manganese oxide-containing activated sludge in Example 2 produced biological manganese oxide BioMnO x , which can replace O 2 Oxidation of NH4 + -N, Mnammox occurs.

[0081] Example 5 Treatment of nitrogen-containing wastewater (actual wastewater)

[0082] This example shows the treatment of wastewater in actual situations, and the specific operation is to continuously introduce nitrogen-containing wastewater into the activated sludge containing biological manganese oxides in Example 2. The following table shows the treatment results of various nitrogen-containing wastewaters.

[0083] Table 1 - Results of the first nitrogen-containing wastewater treatment

[0084] The first nitrogenous wastewater Initial concentration Final concentration <![CDATA[NH 4 + -N]]> 0mg / L 0mg / L <![CDATA[NO 3 - -N]]> 50mg / L 3mg / L

[0085] Among them, the mass ratio of nitrogen-containing wastewater to activated sludge containing biological manganese oxide is 4:1; hydraulic retention time is 12h

[0086] Table 2 - Second nitrogen-containing wastewater treatment results

[0087] Second nitrogen-containing wastewater Initial concentration Final concentration <![CDATA[NH 4 + -N]]> 0mg / L 0mg / L <![CDATA[NO 3 - -N]]> 20mg / L 0.5mg / L

[0088] Among them, the mass ratio of nitrogen-containing wastewater to activated sludge containing biological manganese oxide is 4:1; hydraulic retention time is 6h

[0089] Table 3 - Treatment results of the third nitrogen-containing wastewater

[0090] The third nitrogen-containing wastewater Initial concentration Final concentration <![CDATA[NH 4 + -N]]> 50mg / L 0mg / L <![CDATA[NO 3 - -N]]> 0mg / L 0mg / L

[0091] Among them, the mass ratio of nitrogen-containing wastewater to activated sludge containing biological manganese oxide is 4:1; hydraulic retention time is 12h

[0092] Table 4 - Results of the fourth nitrogen-containing wastewater treatment

[0093]

[0094]

[0095] Among them, the mass ratio of nitrogen-containing wastewater to activated sludge containing biological manganese oxide is 4:1; hydraulic retention time is 6h

[0096] Table 5 - Fifth nitrogen-containing wastewater treatment results

[0097] Fifth, nitrogen-containing wastewater Initial concentration Final concentration <![CDATA[NH 4 + -N]]> 25mg / L 0mg / L <![CDATA[NO 3 - -N]]> 15mg / L 0mg / L

[0098] Among them, the mass ratio of nitrogen-containing wastewater to activated sludge containing biological manganese oxides is 4:1; hydraulic retention time is 8h

[0099] Table 6 - Results of the sixth nitrogen-containing wastewater treatment

[0100] 6. Nitrogen-containing wastewater Initial concentration Final concentration <![CDATA[NH 4 + -N]]> 40mg / L 5mg / L <![CDATA[NO 3 - -N]]> 15mg / L 0mg / L

[0101] Among them, the mass ratio of nitrogen-containing wastewater to activated sludge containing biological manganese oxides is 4:1; the hydraulic retention time is 12h; during the process, an appropriate amount of activated sludge containing biological manganese oxides is added

[0102] Table 7-7 Treatment results of nitrogen-containing wastewater

[0103] 7. Nitrogen-containing wastewater Initial concentration Final concentration <![CDATA[NH 4 + -N]]> 25mg / L 0mg / L <![CDATA[NO 3 - -N]]> 25mg / L 0.5mg / L

[0104] Among them, the mass ratio of nitrogen-containing wastewater to activated sludge containing biological manganese oxide is 4:1; the hydraulic retention time is 12h; and an appropriate amount of manganese chloride tetrahydrate is added during the process.

[0105] The above results show that the use of biological manganese oxide-containing activated sludge in the present application to treat nitrogen-containing wastewater can quickly achieve NH 4 + -N and NO 3 - The total removal rate of -N exceeded 90%.

[0106] The above embodiments are merely illustrative of the principles and effects of the present application and are not intended to limit the present application. Anyone familiar with the technology may modify or change the above embodiments without violating the spirit and scope of the present application. Therefore, all equivalent modifications or changes made by a person of ordinary skill in the art without departing from the spirit and technical ideas disclosed in the present application shall still be covered by the claims of the present application.

Claims

1. A method for preparing activated sludge containing biological manganese oxides, characterized in that: include: S1. Inoculate the activated sludge into the ammonia nitrogen solution; S2, adding manganese-humic acid chelate to step S1 for culturing to obtain the biological manganese oxide-containing activated sludge; Among them, the mass ratio of manganese-humic acid chelate: activated sludge: ammonia nitrogen solution is 20-50: 450-550: 180-220.

2. The method for preparing activated sludge containing biological manganese oxides according to claim 1, characterized in that: In the ammonia nitrogen solution, dissolved oxygen <0.5mg / L, ammonia nitrogen NH4 ＋ -N concentration is 30-60 mg / L.

3. The method for preparing activated sludge containing biological manganese oxides according to claim 1, characterized in that: The culture conditions in step S2 are: sealed culture at 25-35° C. in the dark for 1-12 months.

4. The method for preparing activated sludge containing biological manganese oxides according to claim 1, characterized in that: The manganese-humic acid chelate is prepared by the following method: S21, adding humic acid to a manganese chloride tetrahydrate solution to obtain a mixed solution, wherein the mass ratio of manganese chloride tetrahydrate: distilled water: humic acid is 350-450:1000:40-60; S22, adjusting the pH of the mixed solution in step S21 to 6-8, stirring and centrifuging to obtain a precipitate; S23, washing, drying, grinding and sieving the precipitate obtained in step S22 to obtain the manganese-humic acid chelate.

5. The method for preparing activated sludge containing biological manganese oxides according to claim 4, characterized in that: Step S23 specifically comprises: washing the precipitate obtained in step S22 with distilled water and centrifugally filtering it, drying it at 50-60° C., grinding it, and sieving it through a 10-200 mesh sieve.

6. An activated sludge containing biological manganese oxides, characterized in that: The biological manganese oxide-containing activated sludge is prepared by the preparation method according to any one of claims 1 to 5.

7. Use of the activated sludge containing biological manganese oxides as claimed in claim 6 in treating nitrogen-containing wastewater.

8. A method for treating nitrogen-containing wastewater, characterized in that: include: The nitrogen-containing wastewater is passed into the biological manganese oxide-containing sludge prepared by the preparation method according to any one of claims 1 to 5 or according to claim 6, wherein the mass ratio of the nitrogen-containing wastewater to the biological manganese oxide-containing sludge is 4-100:

1.

9. The method for treating nitrogen-containing wastewater according to claim 8, characterized in that: The inorganic nitrogen in the nitrogen-containing wastewater is ammonia nitrogen, nitric nitrogen or a mixture of ammonia nitrogen and nitric nitrogen; When the inorganic nitrogen in the nitrogen-containing wastewater is a mixture of ammonia nitrogen and nitric nitrogen, if the molar concentration ratio of ammonia nitrogen to nitric nitrogen is less than 5:3, low-valent manganese substances are added to achieve a molar concentration of ammonia nitrogen to nitric nitrogen of 5:3; if the molar concentration ratio of ammonia nitrogen to nitric nitrogen is greater than 5:3, high-valent manganese substances are added to achieve a molar concentration of ammonia nitrogen to nitric nitrogen of 5:

3.

10. The method for treating nitrogen-containing wastewater according to claim 8, characterized in that: The method for treating the nitrogen-containing wastewater adopts a continuous or intermittent water inflow mode, and the hydraulic retention time is ≥ 6h.

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