Biological manganese oxide-containing activated sludge, method for its production and use, and method for treating nitrogen-containing waste water

Abstract

The application discloses a preparation method of activated sludge containing biological manganese oxide and a nitrogen-containing wastewater treatment method, and comprises the following steps: S1, inoculating activated sludge into an ammonia nitrogen solution; S2, adding a manganese-humic acid chelate into the step S1 for culture, so as to obtain the activated sludge containing biological manganese oxide; wherein the mass ratio of the manganese-humic acid chelate, the activated sludge and the ammonia nitrogen solution is 20-50:450-550:180-220. The application utilizes the oxidation (containing a quinone group) reduction (containing a phenol group) capacity of humic acid HA for simultaneously absorbing and supplying electrons, adopts the humic acid HA as a chelating agent, prepares a manganese-humic acid chelate Mn-HA, and generates biological manganese oxide BioMnO x When the activated sludge containing biological manganese oxide is used for treating nitrogen-containing wastewater, the activated sludge can not only oxidize NH4 + -N into NO3 ‑ -N and NO2 ‑ -N under the action of microorganisms, but also reduces the obtained low-valence manganese to NO3 ‑ -N and NO2 ‑ -N into N2 under the action of microorganisms, so that the nitrogen is completely removed.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of nitrogen-containing wastewater treatment, and more particularly to a manganese oxide-containing activated sludge, a preparation method and application thereof, and a treatment method for nitrogen-containing wastewater. BACKGROUND

[0002] Due to human activities such as misuse of fertilizers, discharge of industrial wastewater, etc., nitrogen is overloading in water bodies. Excessive inorganic nitrogen in drinking water is harmful to humans and livestock, leading to water body eutrophication, accelerating the degradation of rivers and lakes, and reducing the available freshwater resources. For the removal of inorganic nitrogen in water bodies, biological methods have the advantages of low cost and environmental friendliness. Traditional biological methods include nitrification and denitrification, which require O2 and additional organic carbon source, respectively, which means more energy consumption. Excessive production of excess sludge and emission of greenhouse gases are also great challenges faced by traditional biological methods for treating ammonia-containing wastewater.

[0003] Recent research has revealed the diversity of ammonia-converting microorganisms, which is of great significance in overcoming the shortcomings of the above-mentioned traditional biological methods. Anaerobic ammonium oxidation has been widely studied due to its advantages such as no additional O2 and carbon source required, low excess sludge production, and no greenhouse gas emission. However, the high sensitivity to environmental conditions limits the large-scale application of anaerobic ammonium oxidation. So far, transition metal redox-mediated anaerobic nitrogen transformation (MRMNT) has been proposed to replace anaerobic ammonium oxidation.

[0004] MRMNT can be defined as a combination of two steps, i) combination of transition metal oxide reduction and ammonia oxidation, in which ammonia is converted into nitrate or nitrite (Mnammox), and ii) low-valence 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 environments. Since the oxidation potential order of general oxidants is O2﹥NO3 - ﹥MnO x ﹥FeO x , MnO x has more advantages than FeO x in converting ammonia into N2, NO2 - and NO3 - (Mnammox). In addition, low-valence iron has the ability to over-reduce nitrate / nitrite to ammonia, which leads to low nitrogen removal efficiency. Therefore, manganese is a better transition metal for regulating nitrogen transformation.

[0005] Therefore, those skilled in the art are committed to researching a manganese-based denitrification substance with low cost, environmental friendliness, simple production process, high nitrogen removal efficiency, and complete pollutant removal. SUMMARY

[0006] In MnO x mediated anaerobic nitrogen transformation process, due to the natural MnO x usually exists in the form of insoluble solid minerals, which leads to limited contact area between MnO x and microorganisms, thereby limiting the reaction rate. In order to improve the solubility and reactivity of MnO x , it is necessary to use some molecules or ions for chelation to increase the contact area between MnO x and microorganisms, thereby improving the reaction efficiency. Humic acid (HA) as a kind of naturally occurring organic molecules (NOM) is widely used in the field of electron shuttle and metal chelation due to its rich functional group structure. In the present application, HA is used as a chelating agent to prepare manganese-humic acid complex (Mn-HA). The rationality of this selection lies in that HA can not only effectively chelate MnO x and significantly improve its solubility and reactivity, but also can enhance the electron transfer process between MnO x and microorganisms due to its rich functional group structure. These characteristics enable Mn-HA to more efficiently promote the anaerobic nitrogen transformation reaction. In addition, the formation of manganese-humic acid chelated manganese (Mn-HA) also has important environmental advantages, which can not only reduce the mobility of manganese, but also reduce the toxicity of manganese, thereby reducing its potential threat to the ecosystem. These characteristics enable Mn-HA to have more stable and efficient performance in the process of anaerobic nitrogen transformation.

[0007] In a first aspect, the present application provides a preparation method of activated sludge containing biological manganese oxide, comprising:

[0008] S1, inoculating activated sludge into an ammonia nitrogen solution;

[0009] S2, adding manganese-humic acid complex Mn-HA to step S1 for culture to obtain the activated sludge containing biological manganese oxide;

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

[0011] Preferably, in the ammonia nitrogen solution, the dissolved oxygen is <0.5 mg / L, and the concentration of ammonia nitrogen NH4 + - N is 30-60 mg / L.

[0012] Preferably, the culture condition in step S2 is: 1-12 months of sealed culture at 25-35℃ under dark condition.

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

[0014] S21, humic acid HA is added into a 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, the pH of the mixed solution in step S21 is adjusted to 6-8, and stirring and centrifugal filtration are performed to obtain a precipitate;

[0016] S23, the precipitate obtained in step S22 is washed, dried, ground and sieved to obtain the manganese-humic acid chelate Mn-HA.

[0017] Preferably, step S23 is specifically: the precipitate obtained in step S22 is washed with distilled water and centrifugal filtration, dried at 50-60℃, then ground and sieved through a 10-200 mesh sieve.

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

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

[0020] In a fourth aspect, the present application provides a treatment method of nitrogen-containing wastewater, which comprises:

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

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

[0023] When the inorganic nitrogen in the nitrogen-containing wastewater is a mixture of ammonia nitrogen and nitrate nitrogen, if the molar concentration ratio of ammonia nitrogen to nitrate nitrogen is less than 5:3, a low-valence manganese substance is added to achieve a molar concentration ratio of ammonia nitrogen to nitrate nitrogen of 5:3; if the molar concentration ratio of ammonia nitrogen to nitrate nitrogen is greater than 5:3, a high-valence manganese substance is added to achieve a molar concentration ratio of ammonia nitrogen to nitrate nitrogen of 5:3.

[0024] Preferably, the treatment method of the nitrogen-containing wastewater adopts a continuous or intermittent water feeding mode, and the hydraulic retention time is ≥6h.

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

[0026] 1、The present application utilizes the oxidation (containing quinone group) reduction (containing phenolic group) ability of humic acid HA to simultaneously absorb electrons and supply electrons, adopts humic acid as a chelating agent, prepares manganese-humic acid chelate Mn-HA, and generates biological manganese oxide BioMnO through the culture of manganese-humic acid chelate Mn-HA in activated sludge x . In the treatment of nitrogen-containing wastewater, biological manganese oxide BioMnO x not only can oxidize NH4 + -N into NO3 - -N and NO2 - -N, but also the reduced low-valence manganese can reduce NO3 - -N and NO2 - -N into N2 under the action of microorganisms, thereby achieving the complete removal of nitrogen.

[0027] 2、Humic acid HA has a large number of functional groups, and the manganese-humic acid chelate Mn-HA prepared by chelating manganese can greatly reduce the toxic effect (even can directly kill microorganisms) of pure manganese oxide on microorganisms, thereby reducing the potential threat to the ecological system.

[0028] 3、The nitrogen-containing wastewater treatment method of the present application does not need to add O2 and carbon source additionally, has low residual sludge yield, and has no greenhouse gas emission.

[0029] The concept, specific structure and generated technical effects of the present application will be further described below in combination with the drawings, so as to fully understand the purpose, features and effects of the present application. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1 It 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 It 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 uneven crystalline shape.

[0032] Figure 3 It is a SEM image of the biological manganese oxide BioMnO x in Example 2 of the present application.

[0033] Figure 4 It is another SEM image of the biological manganese oxide BioMnO x in Example 2 of the present application, which shows that the biological manganese oxide BioMnO xwrapped by the fiber yarns.

[0034] Figure 5 Element content comparison chart of the manganese-humic acid chelate Mn-HA obtained in Example 1 and the biological manganese oxide BioMnO obtained in Example 2. x

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

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

[0037] Figure 8 Element content comparison chart of the biological manganese oxide BioMnO generated in the sludge cultivation process of Example 2. x

[0038] Figure 9 Removal effect chart of NO3- -N by the activated sludge containing biological manganese oxide in Example 2 and the comparative sludge in the comparative example. -

[0039] Figure 10 Removal effect chart of NH4+ -N by the activated sludge containing biological manganese oxide in Example 2 and the comparative sludge in the comparative example. + DETAILED DESCRIPTION

[0040] The present application is described below by way of specific embodiments, and those skilled in the art can easily understand other advantages and effects of the present application from the disclosure of the specification. The present application can also be implemented or applied by other different specific embodiments, and various modifications or changes can be made to the details in the specification based on different views 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 illustrative purposes, and it should be understood that the present application can be implemented in other ways not specifically shown in the drawings.

[0042] In one aspect, the present application discloses a preparation method of activated sludge containing biological manganese oxide, comprising the following steps:

[0043] S1, inoculating activated sludge into an ammonia nitrogen solution;​​​​​​

[0044] S2, culturing with the manganese-humic acid chelate Mn-HA added in step S1 to obtain bio-manganese oxide-containing activated sludge;

[0045] The mass ratio of the 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 a sewage treatment plant.

[0047] The ammonia nitrogen solution in step S1 refers to an aqueous solution containing ammonia nitrogen, which can be configured by itself. Specifically, the ammonia nitrogen solution in the present application can be configured using tap water, and the resulting aqueous solution has a dissolved oxygen (DO) <0.5 mg / L and contains 30-60 mg / L ammonia nitrogen (NH4 + -N) after nitrogen gas (N2) aeration treatment. When the ammonia nitrogen concentration is too low, the nutritional needs of microorganisms cannot be met, resulting in limited microbial growth, especially nitrifying bacteria which 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), the concentration of free ammonia (NH3) increases, which is highly toxic to bacteria and inhibits their activity and proliferation. Therefore, the concentration of ammonia nitrogen (NH4 + -N) in the ammonia nitrogen solution of the present application is controlled at 30-60 mg / L.

[0048] The bio-manganese oxide-containing activated sludge in step S2 refers to the bio-manganese oxide BioMnO x which is generated by culturing the manganese-humic acid chelate Mn-HA in activated sludge, and finally forms activated sludge enriched with specific microorganisms and containing bio-manganese oxide BioMnO x The specific culture conditions in step S2 are: 25-35℃ sealed culture for 1-12 months in the dark.

[0049] The manganese-humic acid chelate Mn-HA in the present application can be directly purchased or prepared, and 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 centrifugal filtration to obtain a gel;

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

[0053] The purpose of step S21 is to obtain a solution containing Mn 2+ , therefore, substances that can provide Mn 2+ such as manganese chloride tetrahydrate, manganese sulfate (MnSO4), manganese carbonate (MnCO3), etc. can be used; 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 substances containing Mn 2+ such as manganese sulfate (MnSO4), manganese carbonate (MnCO3), etc. Humic acid HA can be obtained directly by purchase, and the humic acid HA used in this application is sourced from Shanghai Yuan Ye Biotechnology Co., Ltd.: Detailed information - humic acid (brand: Yuan Ye, product number: S24634); purchase link - [https: / / www.biomart.cn / infosupply / 82603484.htm].

[0054] In step S22, common bases (such as NaOH, KOH, NaHCO3, Na2CO3, etc.) and common acids (such as HCl, HNO3, H2SO4, etc.) are used to adjust the pH to 6-8, preferably 7; during the adjustment of the pH, precipitation will be generated. The reason for choosing this pH range is 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 weak alkaline conditions, part of the carboxyl groups and other groups are partially dissociated to form negative charges, increasing the coordination ability with metal ions; in the pH range of 6.0-8.0, the carboxyl groups and phenolic hydroxyl groups in humic acid HA are in the best dissociation state, which is beneficial to the formation of stable chelates with manganese ions; the solubility and form of manganese ions are affected by the pH value, and in this pH range, manganese ions exist in the form of soluble divalent manganese (Mn 2+ ), which is beneficial to the formation of chelates with humic acid HA. After adjusting the pH, the application is stirred for about 12 hours, and then centrifuged for 10 minutes (for example, at a speed of 12000 rpm), and filtered to obtain a black gel.

[0055] In step S23, the washing specifically refers to rinsing the obtained black gel with distilled water and centrifuging for 10 min (for example, at a speed of 12000 rpm) and then filtering, and the washing step is repeated three times to remove impurities. The drying specifically refers to drying at 50-60°C. The sieving specifically refers to sieving the dried substance through a 10-200 mesh sieve to obtain the manganese-humic acid chelate Mn-HA in the form of black powder. Through the sieving operation, particles with uniform and small particle sizes (the particle size range is approximately 0.074 mm-2 mm) are obtained, 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 the microorganisms. In addition, when the manganese-humic acid chelate Mn-HA with the 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 the surface properties and microbial activity. The particle size after sieving is not the smaller the better, and extremely small particles (for example, sieved through a sieve with a mesh size greater than 200) can enter the cell interior or pass through the bacterial membrane pore, causing oxidative stress or chemical toxicity.

[0056] In another aspect, the application also provides a biological manganese oxide-containing activated sludge prepared by the preparation method described above, which can realize rapid conversion of inorganic nitrogen, and the specific principle is described in detail in the treatment method of nitrogen-containing wastewater below.

[0057] In another aspect, the application also provides a treatment method of nitrogen-containing wastewater, which comprises introducing the nitrogen-containing wastewater into the aforementioned biological manganese oxide-containing activated sludge, wherein the mass ratio of the nitrogen-containing wastewater to the biological manganese oxide-containing activated sludge is 4-100:1. When the nitrogen content is high, the mass ratio of the nitrogen-containing wastewater to the 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. The ratio of the nitrogen-containing wastewater to the biological manganese oxide-containing activated sludge, the treatment time of the nitrogen-containing wastewater, and other factors can be adjusted accordingly according to the total inorganic nitrogen concentration requirement of the drainage, and finally only the wastewater discharge standard needs to be met.

[0058] The treatment of the nitrogen-containing wastewater can be carried out in a continuous or intermittent water feeding mode, and the hydraulic retention time is ≥6 h. According to the total inorganic nitrogen concentration requirement of the drainage, a longer hydraulic retention time can be set.

[0059] The inorganic nitrogen in the nitrogen-containing wastewater can be ammonia nitrogen, nitrate 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 the nitrogen-containing wastewater of the application can realize rapid conversion of inorganic nitrogen. The specific principle is as follows:

[0060] The present application utilizes the oxidation (containing quinone group) reduction (containing phenolic group) ability of humic acid HA which can both absorb and supply electrons, and generates biological manganese oxide BioMnO by culturing manganese-humic acid chelate Mn-HA in activated sludge x The obtained activated sludge containing biological manganese oxide can realize rapid conversion of inorganic nitrogen. The biological manganese oxide BioMnO x (referred to as MnO2 in the following reaction formula) can not only oxidize NH4 + -N to NO3 - -N and NO2 - -N (formula (1)-(3)), but also the obtained low-valence manganese can reduce NO3 - -N and NO2 - -N to N2 (formula (1)-(3)), thereby realizing complete removal of nitrogen.

[0061]

[0062] Further, in the nitrogen-containing wastewater, when the molar concentration ratio of ammonia nitrogen to nitrate nitrogen is 5:3, the treatment effect is best, because the high-valence manganese mediates the direct generation of N2 from ammonia nitrogen and nitrate nitrogen (see formula (6)-(7)), and at this molar concentration ratio, manganese acts as an electron mediator and is not directly lost (will not be consumed), without the need for additional addition:

[0063]

[0064] If the molar concentration ratio of ammonia nitrogen to nitrate nitrogen is less than 5:3, low-valence manganese substances (preferably substances containing divalent manganese) such as manganese-humic acid chelate Mn-HA, manganese chloride tetrahydrate, etc. are added, and the specific amount of addition can be calculated according to the equation for the reaction of nitrate nitrogen with divalent manganese, so as to finally achieve a molar concentration of ammonia nitrogen to nitrate nitrogen of 5:3, and the amount of divalent manganese added is calculated. If the molar concentration ratio of ammonia nitrogen to nitrate nitrogen is greater than 5:3, it indicates that ammonia nitrogen is in the majority and needs to react with more high-valence manganese, at which time high-valence manganese substances (substances containing high-valence manganese such as tetravalent manganese, hexavalent manganese, heptavalent manganese, etc.) need to be added. The activated sludge containing biological manganese oxide in the present application contains a lot of high-valence manganese, so an appropriate amount of activated sludge containing biological manganese oxide can be added to finally achieve a molar concentration of ammonia nitrogen to nitrate nitrogen of 5:3.

[0065] In the above-mentioned treatment method of nitrogen-containing wastewater, the DO in the ammonia nitrogen wastewater is preferably less than 0.5 mg / L (this can be achieved by exposing to nitrogen gas), and the COD content is 60-120 mg / L, at which time no additional organic carbon source needs to be supplied.

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

[0067] 39.6 g of manganese chloride tetrahydrate was dissolved in 100 ml of distilled water. After thorough stirring, a manganese chloride tetrahydrate solution was obtained. 5 g of humic acid (HA) was added to the manganese chloride tetrahydrate solution, and the pH was adjusted to 7. The mixture was stirred for 12 hours, then centrifuged at 12000 rpm for 10 minutes and filtered to obtain a black gelatinous substance. The black gelatinous substance was washed with distilled water and centrifuged at 12000 rpm for 10 minutes, then filtered. This step was repeated three times to remove impurities. The washed black gelatinous substance was dried at 50°C, ground using an agate mortar, and sieved through a 20-mesh sieve to obtain a black powdery substance, manganese-humic acid chelate Mn-HA. The SEM image of manganese-humic acid chelate Mn-HA is shown below. Figures 1-2 As shown in the figure, it can be seen that the manganese-humic acid chelate Mn-HA particles are aggregated together (e.g. Figure 1 As shown), and exhibits an uneven crystalline structure (as shown). Figure 2 (As shown).

[0068] Example 2: Preparation of activated sludge containing bio-manganese oxides

[0069] 25g of Mn-HA prepared in Example 1, 500g of activated sludge (MLVSS 3.5g / L), and 200ml of NH4+ containing 50mg / L aerated with N2 until DO is less than 0.5mg / L were added. + Mix with deionized water containing -N, and incubate in a dark environment at a constant temperature (35℃) for 6 months, with NH4+ added each time. + After the -N is depleted, ammonia nitrogen is replenished in time, the pH is maintained at 6.5-7.0, and the ORP is -150±30mV, finally obtaining activated sludge containing biological manganese oxide.

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

[0071] Figure 5 The manganese-humic acid chelate Mn-HA obtained in Example 1 and the bio-manganese oxide BioMnO obtained in Example 2 are examples of manganese-humic acid chelate Mn-HA obtained in Example 1 and bio-manganese oxide BioMnO obtained in Example 2. x A comparison chart of elemental contents. It can be seen that BioMnO... x The manganese content in the medium is 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 bio-manganese oxide BioMnO obtained in Example 2 are examples of manganese-humic acid chelate Mn-HA obtained in Example 1 and bio-manganese oxide BioMnO obtained in Example 2. x The TIR comparison image shows that at 3430.66 cm⁻¹... -1 The peak at 1615.12 cm⁻¹ represents the vibration of the OH group in phenolic compounds. The absorption peak intensity remains unchanged, indicating that the hydroxyl group represented by this peak does not participate in biochemical processes. -1 and 1384.7cm -1 The peaks at 912.95 cm⁻¹ represent the symmetric vibration and antisymmetric stretching of the carboxyl group, respectively. These peaks originate from HA, and their intensity remains constant, indicating that HA may not have been lost during the biochemical process. -1 and 798.48cm -1 The bands represent the stretching of -CO-, which is produced by phenolic groups and aromatic ethers in microbial secretions adhering to Mn-HA; BioMnO x The absorption peak is at 400-500 cm⁻¹ -1 The absorption peaks within this range are enhanced, and this range corresponds to the lattice vibrations of Mn-O, indicating that the bio-manganese oxide BioMnO... x The generation of.

[0073] Figure 7 The manganese-humic acid chelate Mn-HA obtained in Example 1 and the bio-manganese oxide BioMnO obtained in Example 2 are examples of manganese-humic acid chelate Mn-HA obtained in Example 1 and bio-manganese oxide BioMnO obtained in Example 2. x The XRD comparison plots show that the peaks at 2θ = 12.320° and 24.966° correspond to K. 0.27 MnO2(H2O) 0.54 Similar substances. Typical characteristic peaks of MnCl₂·2H₂O appeared at 2θ = 20.169° and 50.839°. Compared with Mn-HA, bio-manganese oxide BioMnO x In K 0.27 MnO2(H2O) 0.54 The reduced degree of crystallization in MnCl2·2H2O is related to the distortion of crystal structure caused by microbial corrosion.

[0074] During the implementation of the present embodiment, 10 mL of the homogenized mixture of sludge and water, which was sealed and cultured for one month, three months and six months respectively, was taken into a 50 mL centrifuge tube, then 10 mL of 0.04% triphenylmethane compound albumin blue (LBB) solution was added, and the mixture was placed in the dark for 8 minutes. The results are shown in Figure 8 As can be seen from the figure, with the extension of the culture time of Mn-HA, the blue color deepens, indicating that the longer the culture time, the more BioMnOx is produced. x As can be seen from the figure, with the extension of the culture time of Mn-HA, the blue color deepens, indicating that the longer the culture time, the more BioMnOx is produced.

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

[0076] 500 g of activated sludge (MLVSS 3.5 g / L) and 200 mL of deionized water containing 50 mg / L NH4 + -N, which was aerated with N2 to a DO less than 0.5 mg / L, were mixed, and the mixture was sealed and cultured at a constant temperature (35°C) in the dark for 6 months. After the NH4 + -N was depleted each time, ammonia nitrogen was supplemented in time, the pH was maintained at 6.5-7.0, and the ORP was -150±30 mV. The sludge obtained by this method was the comparative sludge.

[0077] Treatment of nitrogen-containing wastewater (prepared wastewater) in Example 1

[0078] 50 mL of the activated sludge containing BioMnOx in Example 2 and 50 mL of the comparative sludge in the comparative example were taken respectively, and 200 mL of deionized water containing 10, 15, 20, 40 and 60 mg / L of NO3 - -N was added to a serum bottle. Then the serum bottle was sealed and placed in a constant temperature (35°C) dark environment, and the results are shown in Figure 9 As can be seen from the figure, under different initial NO3 - -N concentrations, the denitrification rate constant K of the activated sludge containing BioMnOx in Example 2 is higher than that of the comparative sludge in the comparative example.

[0079] Treatment of nitrogen-containing wastewater (prepared wastewater) in Example 2

[0080] 50 mL of the activated sludge containing BioMnOx in Example 2 and 50 mL of the comparative sludge in the comparative example were taken respectively, and 200 mL of deionized water containing 10, 15, 20, 40 and 60 mg / L of NO3 + -N was added to a serum bottle. Then the serum bottle was sealed and placed in a constant temperature (35°C) dark environment, and the results are shown in Figure 10 As can be seen from the figure, under different initial NO3 + -N concentrations, the denitrification rate constant K of the activated sludge containing BioMnOx in Example 2 is higher than that of the comparative sludge in the comparative example. +-N is removed quickly, while the comparative sludge in Comparative Example 1 has little NH4 + -N removal ability, i.e. anaerobic environment cannot support NH4 + -oxidation of N, the bio-manganese-oxide-containing activated sludge in Example 2 produces bio-manganese oxide BioMnO x , which can replace O2 to oxidize NH4 + -N, Mnammox occurs.

[0081] Example 5 Treatment of Nitrogen-containing Wastewater (Actual Wastewater)

[0082] This example shows the treatment of wastewater in actual situation, and the specific operation is that the nitrogen-containing wastewater is introduced into the bio-manganese-oxide-containing activated sludge in Example 2 in a continuous water feeding mode. The following table shows the treatment results of each nitrogen-containing wastewater.

[0083] Table 1 - Treatment results of the first nitrogen-containing wastewater

[0084] First nitrogen-containing wastewater Initial concentration Final concentration NH4 + -N]]> 0 mg / L 0 mg / L NO3 - -N]] 50 mg / L 3 mg / L

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

[0086] Table 2 - Treatment results of the second nitrogen-containing wastewater

[0087] Second nitrogen-containing wastewater Initial concentration Final concentration NH4 + -N]]> 0 mg / L 0 mg / L NO3 - -N]] 20 mg / L 0.5 mg / L

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

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

[0090] Third nitrogen-containing wastewater Initial concentration Final concentration NH4 + -N]]> 50 mg / L 0 mg / L NO3 - -N]] 0 mg / L 0 mg / L

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

[0092] Table 4 - Treatment results of the fourth nitrogen-containing wastewater

[0093]

[0094]

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

[0096] Table 5 - Treatment results of the fifth nitrogen-containing wastewater

[0097] Fifth nitrogen-containing wastewater Initial concentration Final concentration NH4 + -N]]> 25 mg / L 0 mg / L NO3 - -N]] 15 mg / L 0 mg / L

[0098] The nitrogen-containing wastewater: biogenic manganese oxide-containing activated sludge mass ratio = 4:1; the hydraulic retention time is 8h

[0099] Table 6 - the seventh nitrogen-containing wastewater treatment results

[0100] Sixth nitrogen-containing wastewater Initial concentration Final concentration NH4 + -N]] 40 mg / L 5 mg / L NO3 - -N]] 15 mg / L 0 mg / L

[0101] The nitrogen-containing wastewater: biogenic manganese oxide-containing activated sludge mass ratio = 4:1; the hydraulic retention time is 12h; and the biogenic manganese oxide-containing activated sludge is added in proper amount during the process

[0102] Table 7 - the seventh nitrogen-containing wastewater treatment results

[0103] Seventh nitrogen-containing wastewater Initial concentration Final concentration NH4 + -N]] 25 mg / L 0 mg / L NO3 - -N]] 25 mg / L 0.5 mg / L Seventh nitrogen-containing wastewater Initial concentration Final concentration 25 mg / L 0 mg / L 25 mg / L 0.5 mg / L Seventh nitrogen-containing wastewater Initial concentration Final concentration 25 mg / L 0 mg / L 25 mg / L 0.5 mg / L Seventh nitrogen-containing wastewater Initial concentration Final concentration 25 mg / L 0 mg / L 25 mg / L 0.5 mg / L Seventh nitrogen-containing wastewater Initial concentration Final concentration 25 mg / L 0 mg / L 25 mg / L 0.5 mg / L Seventh nitrogen-containing wastewater Initial concentration Final concentration 25 mg / L 0 mg / L 25 mg / L 0.5 mg / L Seventh nitrogen-containing wastewater Initial concentration Final concentration 25 mg / L 0 mg / L 25 mg / L 0.5 mg / L Seventh nitrogen-containing wastewater Initial concentration Final concentration 25 mg / L 0 mg / L 25 mg / L 0.5 mg / L Seventh nitrogen-containing wastewater Initial concentration Final concentration 25 mg / L 0 mg / L 25 mg / L 0.5 mg / L Seventh nitrogen-containing wastewater Initial concentration Final concentration 25 mg / L 0 mg / L 25 mg / L 0.5 mg / L Seventh nitrogen-containing wastewater Initial concentration Final concentration 25 mg / L 0 mg / L 25 mg / L 0.5 mg / L Seventh nitrogen-containing wastewater Initial concentration Final concentration 25

[0104] The nitrogen-containing wastewater: biogenic manganese oxide-containing activated sludge mass ratio = 4:1; the hydraulic retention time is 12h; and the manganese chloride tetrahydrate is added in proper amount during the process

[0105] The above results show that the nitrogen-containing wastewater is treated by using the biogenic manganese oxide-containing activated sludge of the present application, and the NH4 + -N and NO3 - -N can be quickly removed, and the total removal rate of -N is more than 90%.

[0106] The above examples are only illustrative of the principles and effects of the present application, and are not used to limit the present application. Any person skilled in the art can modify or change the above examples without departing from the spirit and scope of the present application. Therefore, all equivalent modifications or changes completed by those skilled in the art without departing from the spirit and technical thought of the present application should be covered by the claims of the present application.

Claims

1. A method for producing a biological manganese oxide-containing activated sludge, characterized by, The application relates to a preparation method of a biological manganese oxide-containing activated sludge. S1, inoculating activated sludge into an ammonia-nitrogen solution, wherein the dissolved oxygen is less than 0.5 mg / L, and the concentration of ammonia-nitrogen NH4+-N is 30-60 mg / L; S2, adding a manganese-humic acid chelate to the solution in step S1 to culture, to obtain the biological manganese oxide-containing activated sludge, wherein the particle size of the manganese-humic acid chelate is 0.074 mm-2 mm, and the culture condition in step S2 is as follows: 25-35 DEG C sealed culture in dark for 1-12 months; The mass ratio of the manganese-humic acid chelate, the activated sludge and the ammonia-nitrogen solution is 20-50:450-550:180-220. The manganese-humic acid chelate is prepared by the following method: S21, adding humic acid into a manganese chloride tetrahydrate solution to obtain a mixed solution, wherein the mass ratio of the manganese chloride tetrahydrate, distilled water and humic acid is 350-450:1000:40-60; S22, adjusting the pH of the mixed solution in step S21 to 6-8, stirring and centrifugal filtration to obtain a precipitate; S23, washing, drying, grinding and sieving the precipitate obtained in step S22 to obtain the manganese-humic acid chelate.

2. The method for producing a biological manganese oxide-containing activated sludge according to claim 1, characterized by: The step S23 is specifically as follows: washing and centrifugal filtration of the precipitate obtained in step S22 with distilled water, drying at 50-60 DEG C, grinding and sieving through a 10-200 mesh sieve.

3. A biological manganese oxide-containing activated sludge, characterized by, The biological manganese oxide-containing activated sludge is prepared by the preparation method in any one of claims 1-2.

4. Application of the biological manganese oxide-containing activated sludge in claim 3 to treatment of nitrogen-containing wastewater.

5. A method for treating nitrogen-containing wastewater, characterized by, The application comprises the following steps: The nitrogen-containing wastewater is introduced into the biological manganese oxide-containing activated sludge prepared by the preparation method in any one of claims 1-2 or the biological manganese oxide-containing activated sludge in claim 3, wherein the mass ratio of the nitrogen-containing wastewater and the biological manganese oxide-containing activated sludge is 4-100:

1.

6. The method of treating nitrogen-containing wastewater of claim 5, wherein, The inorganic nitrogen in the nitrogen-containing wastewater is ammonia nitrogen, nitrate nitrogen or a mixture of ammonia nitrogen and nitrate nitrogen; When the inorganic nitrogen in the nitrogen-containing wastewater is a mixture of ammonia nitrogen and nitrate nitrogen, if the molar concentration ratio of ammonia nitrogen to nitrate nitrogen is less than 5:3, a low-valence manganese substance is added to achieve the molar concentration ratio of 5:3; if the molar concentration ratio of ammonia nitrogen to nitrate nitrogen is greater than 5:3, a high-valence manganese substance is added to achieve the molar concentration ratio of 5:

3.

7. The method of treating nitrogen-containing wastewater of claim 5, wherein, The treatment method of the nitrogen-containing wastewater adopts a continuous or intermittent water feeding mode, and the hydraulic retention time is greater than or equal to 6 h.

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