Nitration / denitrification bacteria agent synergistic nutrient agent and its application

Abstract

The application discloses a nitrification / denitrification bacteria agent synergistic nutrient agent and application thereof, and belongs to the technical field of wastewater biological treatment. The synergistic nutrient agent comprises a pollutant high-efficiency adsorption enhancement component and an in-situ catalytic degradation active construction component; by adding the synergistic nutrient agent into a biological reactor of a wastewater biological treatment system, a functionalized biofilm is constructed, so that the biofilm is changed from a passive microbial carrier into a multifunctional purification platform integrating pollutant high-efficiency adsorption, in-situ catalytic degradation and biological denitrification. The application can simultaneously realize deep removal of nitrogen and heavy metals, phenols, BPA, antibiotic intermediates and other various exogenous inhibitory pollutants, and solves the problem of low efficiency of a traditional biological denitrification process in the presence of toxic substances. The method is suitable for various processes such as MBBR, biological filter, A / O and A / A / O, and has a wide application prospect.

Description

Technical Field

[0001] This invention belongs to the field of wastewater biological treatment technology. Specifically, it relates to a synergistic nutrient agent for nitrifying / denitrifying bacteria and its application. In particular, it is a method for developing and applying a synergistic nutrient agent that can enhance the biofilm's high-efficiency adsorption capacity for exogenous pollutants and construct in-situ catalytic degradation activity within the biofilm, thereby achieving synergistic denitrification by nitrifying / denitrifying bacteria and deep purification of pollutants. Background Technology

[0002] Biological wastewater treatment technology, especially biological denitrification processes based on the synergistic action of nitrifying and denitrifying bacteria, has always been a key means of removing nitrogen pollution from water, and is of great significance for controlling eutrophication and maintaining ecological security. This technology relies on microbial metabolism to convert ammonia nitrogen into nitrogen gas, achieving effective nitrogen removal. However, with industrial development and the increasing complexity of wastewater composition, traditional biological denitrification systems are facing severe challenges.

[0003] Currently widely used traditional processes, such as activated sludge and biofilm processes, primarily promote nitrification and denitrification by providing suitable environments (such as carbon and nitrogen sources and anoxic / aerobic conditions), and are highly effective in treating wastewater mainly polluted with nitrogen. To maintain microbial activity, nutrients are often added or the carrier and hydraulic conditions are optimized to enhance biofilm stability. These methods have effectively addressed nitrogen removal requirements in earlier stages.

[0004] However, current wastewater often contains inhibitory pollutants such as heavy metals, highly toxic organic matter, and endocrine disruptors, which are highly toxic to nitrifying and denitrifying bacteria, inhibiting enzyme activity, damaging cell structure, and leading to decreased denitrification efficiency or even system failure. Existing biological denitrification systems are designed with nitrogen conversion as the primary focus, lacking an active and efficient mechanism for removing exogenous inhibitors. Although biofilms can adsorb some pollutants through extracellular polymeric substances (EPS), this process is non-specific, has limited capacity, is easily saturated, and cannot degrade pollutants, leaving them more in a passive state than an active removal process. Therefore, it is often necessary to couple advanced oxidation and membrane separation methods to remove toxic substances, resulting in complex processes, increased costs, increased land occupation, and potential secondary pollution. Fundamentally, the design of traditional biological denitrification systems has not integrated the function of "identifying-capturing-degrading" inhibitory pollutants into the biofilm system, resulting in insufficient resistance and limited function of microorganisms under combined pollution stress.

[0005] Therefore, how to break through the limitation of biological units only targeting the removal of specific pollutants, systematically improve the multifunctionality of biofilms, and evolve them from simple microbial carriers into composite platforms with both denitrification and pollutant adsorption-catalytic degradation capabilities, while ensuring the activity of nitrifying / denitrifying microorganisms and achieving efficient synergistic purification of nitrogen and other toxic substances, has become a technical bottleneck that urgently needs to be overcome in this field. Summary of the Invention

[0006] To address the limitations of existing biological wastewater denitrification systems in treating exogenous and inhibitory pollutants, this invention provides a synergistic nutrient agent for nitrification / denitrification bacteria and its application method. The aim is to transform traditional biofilms from passive microbial carriers into multifunctional purification platforms integrating efficient pollutant adsorption, in-situ catalytic degradation, and biological denitrification, thereby achieving deep wastewater purification and efficient removal of nitrogen pollution.

[0007] To achieve the above-mentioned objectives, the present invention employs the following technical solution: This invention provides a synergistic nutrient agent, which comprises a pollutant-efficient adsorption-enhancing component and an in-situ catalytic degradation-active component; The pollutant adsorption enhancement component is selected from zinc-cysteine ​​complex or manganese-citrate complex, chitosan oligosaccharide or quaternized chitosan oligosaccharide with an average degree of polymerization of 5, short peptides rich in glutamic acid and aspartic acid or short peptides rich in phenylalanine and tyrosine, and a mixture of L-glutamic acid and glutamic acid dipeptide. The in-situ catalytic degradation active building blocks are selected from microencapsulated copper-glycine complexes, riboflavin or heme, combinations of ferrous salts and citric acid, and hydrolyzable titanium salts and polyvinylpyrrolidone.

[0008] In one embodiment, the pollutant-efficient adsorption-enhancing component is a zinc-cysteine ​​complex, a chitosan oligosaccharide with an average degree of polymerization of 5, and a short peptide rich in glutamic acid and aspartic acid; the in-situ catalytic degradation active building component is a copper-glycine complex, a combination of ferrous sulfate and citric acid.

[0009] In one embodiment, the pollutant high-efficiency adsorption enhancement component is a manganese-citrate complex, quaternized chitosan oligosaccharide, and polyγ-glutamic acid precursor; the in-situ catalytic degradation active building component is riboflavin, isopropyl titanate-ethanol, and polyvinylpyrrolidone.

[0010] The present invention also provides an application of the aforementioned synergistic nutrient in enhancing biological denitrification and co-removal of pollutants in wastewater, characterized in that the synergistic nutrient is added to the bioreactor of a wastewater biological treatment system to construct a functionalized biofilm; the functionalized biofilm simultaneously achieves biological denitrification and adsorption and degradation of heavy metals and organic toxins.

[0011] Furthermore, the functionalized biomembrane is capable of adsorbing and degrading exogenous inhibitory pollutants in situ.

[0012] Furthermore, the exogenous inhibitory pollutants include one or more of cadmium, hexavalent chromium, phenolic compounds, bisphenol A, and antibiotic intermediates.

[0013] Furthermore, the dosing method is either continuous dosing or pulsed intermittent dosing. Beneficial effects

[0014] (1) This invention breaks through the technical bottleneck of traditional process "denitrification leads to poisoning, and detoxification leads to denitrification failure". While achieving efficient denitrification (TN removal rate up to 88%–98.8%), it also achieves deep synergistic removal of a variety of characteristic toxic pollutants (such as phenols, BPA, Cd(II), Cr(VI) etc.) (removal rate > 97.5%), and the effluent water quality is comprehensively better than the discharge requirements.

[0015] (2) This invention induces a fundamental evolution in the function of the biofilm through nutrient induction, upgrading it from a single microbial carrier to an active purifier with multiple functions of "front-end adsorption-in-situ catalysis-core denitrification". It significantly enhances the EPS barrier and successfully induces the synthesis of key catalytic enzymes such as laccase and nitroreductase, gaining new functions of degrading organic toxins and reducing heavy metals. At the same time, the activity of core denitrases (AMO, Nar) is still significantly enhanced under toxic stress.

[0016] (3) By integrating multiple functions within the biochemical unit, this invention significantly reduces the reliance on expensive subsequent units such as advanced oxidation and deep filtration, thereby significantly reducing infrastructure investment and operating costs, which aligns with the green and low-carbon development trend of wastewater treatment.

[0017] (4) The nutrient components of the present invention are clearly defined, and the application method (continuous or intermittent addition) is flexible. Without changing the main process structure, it can efficiently empower and upgrade existing mainstream wastewater treatment systems such as MBBR, biological filter, and A / A / O. It is suitable for treating industrial wastewater and municipal sewage with complex components and has high promotion value. Detailed Implementation

[0018] To enable those skilled in the art to better understand the technical solutions of this invention, the present application will be further described in detail below with reference to embodiments.

[0019] The synergistic nutrient agent described in this invention does not consist of two components that act independently. Instead, they work together through a tandem synergistic mechanism of "frontal adsorption-in-situ degradation-bioprotection" to jointly address the challenges of toxicity inhibition and denitrification failure. Its mechanism of action is as follows: The role of the pollutant-efficient adsorption enhancement component: This component first acts on the microorganisms on the biofilm, significantly stimulating them to secrete more extracellular polymers (EPS) with abundant functional groups (such as carboxyl, thiol, and amino groups) by providing specific signaling molecules or structural precursors (e.g., trace elements, specific oligosaccharides, and peptides). This greatly enhances the biofilm's ability to adsorb heavy metal ions (such as Cd) in water. 2+ Cr 6+The adsorption capacity and rate of hydrophobic organic toxins (such as phenols and BPA) enable the rapid enrichment and fixation of pollutants. This process "intercepts" high concentrations of toxic substances in the outer region of the biofilm, greatly reducing their diffusion into the biofilm and constructing the first physicochemical barrier for the internal nitrifying / denitrifying bacteria community.

[0020] The role of the in-situ catalytic degradation active building component: This component constructs a catalytic center within the biomembrane through two pathways: a. Enzyme-inducible pathway: providing enzyme cofactors or precursors (such as Cu). 2+ (a) Riboflavin, heme) are utilized by microorganisms, specifically inducing high expression of degrading enzymes such as laccase, peroxidase, and nitroreductase, and immobilizing these enzymes in the EPS network. b. Nanocatalytic pathway: The provided metal precursor reacts with reducing agents or templates (such as Fe²⁺ / citric acid, titanate / PVP) in the microenvironment of the biofilm, generating and stabilizing highly catalytically active nanomaterials (such as nZVI, TiO2) in situ. These catalytic sites directly act on the adsorbed and enriched pollutants, catalytically degrading or converting them into less toxic substances (such as Cr). 6+ Reduced to Cr 3+ (This oxidizes phenols into quinones, which then undergo ring-opening degradation).

[0021] Synergistic effect: The functions of the two components are closely coupled in time and space and occur sequentially.

[0022] Spatial synergy: The enrichment environment created by the "adsorption-enhancing component" provides a high concentration of reaction substrate for the "catalytic degradation component", which significantly improves the kinetic rate of the catalytic reaction and solves the problem of slow reaction rate at low concentrations.

[0023] Synergistic Function: The "catalytic degradation component" degrades the adsorbed toxins in a timely manner, avoiding the saturation of adsorption sites and the penetration of toxins, thereby maintaining and refreshing the long-term effectiveness of the barrier function constructed by the "adsorption enhancement component".

[0024] Final effect: The synergistic effect of the above mechanisms ensures that the nitrifying / denitrifying bacteria in the core functional area can maintain high metabolic activity in a microenvironment with significantly reduced toxicity and environmental stability, thereby achieving the dual goals of denitrification and deep detoxification simultaneously. This "1+1>2" effect is the essence of the "synergistic effect" of this invention.

[0025] The nutrient addition described in this invention achieves precise dosing through an integrated intelligent system, optimizing its contact with the biofilm and its functionalization effect. This system comprises the following components: (1) High-precision metering pump: such as electromagnetic metering pump (ProMinent® gamma / X type), with flow accuracy of ±1% and adjustment range of 0.001–30 L / h.

[0026] (2) Online monitoring sensors: including pH electrode, optical DO sensor, ORP electrode, temperature sensor, spectral sensor (such as UV-Vis spectrometer for monitoring COD and nitrate) or electrochemical sensor (such as ISE electrode for monitoring heavy metals with ppb accuracy). Data is transmitted via Modbus / Profibus protocol, and the sampling frequency is 5–30 minutes / time.

[0027] (3) Biofilm physiological status monitoring module: including ATP biomass detector, flow cytometer (based on SYBR Green I / PI staining of live and dead bacteria), qPCR or FISH system (quantitative analysis of functional genes such as amoA and nxrA), used to assess microbial activity and community structure.

[0028] (4) Data acquisition and control unit: PLC (such as Siemens S7-1500) or DCS (such as ABB 800xA) are used to process data and execute control commands in real time.

[0029] (5) Control algorithm: Combining PID control, fuzzy logic control and model predictive control (MPC). MPC takes the influent pollution load, biofilm activity and effluent water quality as inputs and optimizes the dosing strategy through dynamic model. For example, when the Cd(II) concentration is detected to rise from 0.1 mg / L to 0.5 mg / L, the system automatically increases the dosage of adsorption enhancement component by 15%–25% within 10 minutes to ensure that the effluent Cd(II) < 0.01 mg / L. Example 1

[0030] This embodiment aims to verify the ability of the synergistic nutrient agent described in this invention to construct a functionalized biofilm in a moving bed biofilm reactor (MBBR) and synergistically remove nitrogen, phenolic compounds and heavy metal Cd(II).

[0031] 1. Experimental setup and operating conditions Three parallel MBBR reactors, each with a total volume of 10 L, were used, with a polyethylene carrier filling rate of 50%. All reactors were operated at ambient temperature (25±1°C), pH 7.0±0.2, with dissolved oxygen (DO) maintained at 2.0-3.0 mg / L in the aerobic zone and 0.3-0.5 mg / L in the anoxic zone. The hydraulic retention time (HRT) was set to 8 hours.

[0032] The influent was artificially simulated wastewater, containing: NH4Cl (25 mg / L as NH4-N), NaNO3 (15 mg / L as NO3-N), glucose (250 mg / L as COD), phosphate (5 mg / L as PO4-P), and trace elements. In addition, phenolic compounds (50 mg / L) and CdCl2 (1 mg / L as Cd(II)) were added to the influent.

[0033] 2. Preparation and Dosing of Synergistic Nutrients The synergistic nutrients used contain the following components: (1) Highly efficient pollutant adsorption enhancement components: Zinc-cysteine ​​complex: A commercially available product is used. This product is a water-soluble chelate with a zinc content of 20-22%. When using, it is prepared as an aqueous solution with a concentration of 20 g / L.

[0034] Chitosan oligosaccharide: a solution with an average degree of polymerization of 5 and a concentration of 20 g / L.

[0035] A short peptide ((Glu-Asp)5) rich in glutamic acid and aspartic acid was synthesized by a commissioned company: the synthesis was carried out in a solution with a purity of >95% and a concentration of 10 g / L.

[0036] (2) Components for constructing in-situ catalytic degradation activity: Copper-glycine complex: The copper source produced using fluidized bed coating technology is a commercially available product. This product consists of functional particles composed of copper and amino acid complexes coated with a lipid layer, with an average particle size of 50 micrometers and a copper loading of 10%. For use, it is dispersed in water to prepare a suspension with a concentration of 50 g / L.

[0037] Ferrous sulfate solution: FeSO4·7H2O solution with a concentration of 50 g / L.

[0038] Citric acid solution: Citric acid solution with a concentration of 20 g / L.

[0039] Nutrients were added to the MBBR reactor inlet via a high-precision peristaltic pump (flow accuracy ±1%). The dosages of the synergistic nutrients were as follows: zinc-cysteine ​​complex solution 1 mL / L wastewater, chitosan oligosaccharide solution 2 mL / L wastewater, (Glu-Asp)5 short peptide solution 0.5 mL / L wastewater, copper-glycine complex microcapsule suspension 0.1 mL / L wastewater, ferrous sulfate solution 1 mL / L wastewater, and citric acid solution 0.5 mL / L wastewater. The addition was continuous. Example 2

[0040] This embodiment aims to verify the effectiveness of the synergistic nutrient agent described in this invention in constructing a functionalized biofilm in a biofilter and synergistically removing nitrogen, recalcitrant organic matter, and heavy metal Cr(VI) when treating highly toxic pharmaceutical wastewater.

[0041] 1. Experimental setup and operating conditions Two parallel upflow biological filters (UBFs) were used, each with an effective volume of 15 L, filled with ceramic ring biological packing material. The reactor operating temperature was 28±1°C, and the pH was maintained at 7.5±0.3. Dissolved oxygen (DO) in the aerobic zone was controlled at 3.0-4.0 mg / L through bottom aeration. The hydraulic retention time (HRT) was set to 12 hours.

[0042] The influent is actual pretreated pharmaceutical wastewater, whose core components are: NH4Cl (replenished to NH4-N 40 mg / L), K2Cr2O7 (calculated as Cr(VI) 2 mg / L), and inherent recalcitrant organic matter (calculated as COD approximately 500 mg / L, mainly containing antibiotic intermediates and residual solvents).

[0043] 2. Preparation and Dosing of Synergistic Nutrients The synergistic nutrient used contains the following components: (1) Highly efficient pollutant adsorption enhancement components: Manganese-citrate complex: Dissolve 0.3 g MnSO4·H2O and 0.2 g sodium citrate in 100 mL of deionized water to prepare a concentrated solution.

[0044] Quaternized chitosan oligosaccharide: A commercially available product with a degree of substitution (DS) ≥ 95% and a degree of polymerization of 3-7 is used. It is prepared as a 15 g / L aqueous solution.

[0045] Poly-γ-glutamic acid (PGA) precursor: a mixture of L-glutamic acid and glutamic acid dipeptide in a solution with a concentration of 50 g / L.

[0046] (2) Components for constructing in-situ catalytic degradation activity: Riboflavin solution: A commercially available product is used, which uses microencapsulation technology to encapsulate riboflavin in a plant gum and starch matrix to improve its stability and controlled release. It is prepared as a suspension with a concentration of 10 g / L for use.

[0047] Isopropyl titanate-ethanol solution: Dissolve 5 mL of isopropyl titanate in 95 mL of anhydrous ethanol and store in the dark.

[0048] Polyvinylpyrrolidone (PVP) solution: a solution with a molecular weight of 10,000 and a concentration of 10 g / L.

[0049] Nutrients were added to the influent distributor of the biological filter via a precision metering pump. The specific dosages were: 1.5 mL / L manganese-citrate complex solution, 1 mL / L quaternized chitosan oligosaccharide solution, 2 mL / L PGA precursor solution, 0.2 mL / L riboflavin microcapsule suspension, 0.05 mL / L isopropyl titanate-ethanol solution, and 0.1 mL / L PVP solution. An intermittent pulse dosing mode was used, with additions every 4 hours. Example 3

[0050] This embodiment aims to verify the performance of the present invention in enhancing the traditional activated sludge system (A / A / O process) in the synergistic removal of organic toxins (taking bisphenol A / BPA as an example) and nitrogen from municipal wastewater.

[0051] 1. Experimental setup and operating conditions Experiments were conducted on a small-scale anaerobic-anoxic-aerobic (A / A / O) activated sludge system with a total effective volume of 30 L (anaerobic:anoxic:aerobic = 1:1:2). The system operating temperature was 20±2°C, and the pH was 7.2±0.2. The ORF in the anaerobic zone was <-250 mV, the DO in the anoxic zone was <0.2 mg / L, and the DO in the aerobic zone was 2.0±0.5 mg / L. The sludge retention time (SRT) was controlled at 15 days, and the mixed liquor suspended solids (MLSS) concentration was approximately 3500 mg / L.

[0052] The influent is simulated municipal sewage, mainly containing: peptone, beef extract (providing approximately 300 mg / L COD, approximately 30 mg / L NH4-N, and approximately 5 mg / L TP), and additionally bisphenol A (BPA, 2 mg / L).

[0053] 2. Preparation and Dosing of Synergistic Nutrients The synergistic nutrient used contains the following components: (1) Highly efficient pollutant adsorption enhancement components: Hydrophobic xylo-oligosaccharide derivative: A commercially available product is used, which is a mixture of cetearyl alcohol and cocoyl glucoside, exhibiting good surface activity and hydrophobic modification properties. It is formulated as an emulsion with a concentration of 10 g / L for use.

[0054] Phenylalanine-rich short peptide ((Phe-Tyr)4): A commercially available product containing a hydrophobic amino acid sequence including phenylalanine is used. Prepare a solution with a concentration of 5 g / L before use.

[0055] (2) Components for constructing in-situ catalytic degradation activity: Laccase cofactor enhancer: a copper-histidine complex (0.1 g / L CuSO4·5H2O + 0.08 g / L L-histidine).

[0056] Hemin solution: an alkaline solution with a concentration of 0.2 g / L (dissolved with a small amount of NaOH).

[0057] Nutrients were added to the anoxic and aerobic zones of the A / A / O system via precision pumps. A hydrophobic xylooligosaccharide derivative emulsion (1 mL / L wastewater) and a (Phe-Tyr)4 short peptide solution (0.5 mL / L wastewater) were added to the inlet of the anoxic zone. Laccase cofactor enhancer (0.3 mL / L wastewater) and heme solution (0.1 mL / L wastewater) were added to the middle of the aerobic zone. A continuous dosing method linked to the influent flow rate was employed.

[0058] Comparative Example 1 Another MBBR system was operated under the exact same apparatus, influent water quality, and operating conditions as in Example 1, the only difference being that no synergistic nutrients were added.

[0059] Comparative Example 2 Another biological filter system was operated under the exact same apparatus, influent water quality, and operating conditions as in Example 2, without the addition of nutrients.

[0060] Comparative Example 3 The device was operated under the same A / A / O apparatus, influent water quality, and operating conditions as in Example 3, without the addition of nutrients.

[0061] Effect verification 1. The following tests were conducted on Example 1 and Comparative Example 1, and the results are summarized in Table 1.

[0062] (1) Ammonia nitrogen (NH4-N) concentration: The treated water sample was reacted with Nessler's reagent to form a yellow-brown complex. The absorbance was measured at a wavelength of 420 nm, and the concentration was calculated according to the standard curve.

[0063] (2) Nitrate nitrogen (NO3-N) concentration: The concentration was determined by the ultraviolet absorbance of nitrate ions at wavelengths of 220 nm and 275 nm.

[0064] (3) Total nitrogen (TN) concentration: The water sample was digested with potassium sulfate under alkaline conditions to convert various forms of nitrogen compounds into nitrates, and then the concentration was determined by ultraviolet spectrophotometry of nitrate nitrogen.

[0065] (4) Removal rate of phenolic compounds: After distillation, phenolic compounds react with 4-aminoantipyrine to generate orange antipyrine dye, which is determined by high performance liquid chromatography.

[0066] (5) Cd(II) removal rate: After acidification, the water sample was directly injected into a graphite furnace atomic absorption spectrometer, and the absorbance of cadmium was measured at a wavelength of 228.8 nm.

[0067] (6) Protein content in EPS: Take the extracted EPS solution, add Coomassie Brilliant Blue G-250 dye, and measure the absorbance at 595 nm. Use bovine serum albumin (BSA) as a standard curve.

[0068] (7) Polysaccharide content in EPS: Take the extracted EPS liquid, react it with phenol and concentrated sulfuric acid to generate an orange-yellow compound, and measure the absorbance at 490 nm. Use glucose as a standard curve.

[0069] (8) Laccase activity: The biofilm sample was mixed with ABTS substrate buffer, and the rate of change of absorbance at 420 nm over time was monitored. 1 U is defined as the amount of enzyme required to oxidize 1 μmol of ABTS per minute.

[0070] (9) Ammonia monooxygenase (AMO) activity: Enzyme activity is calculated by measuring the concentration of hydroxylamine, an intermediate product in the ammonia oxidation process, or by comparing the difference in ammonia oxidation rates with and without acetylene inhibitors.

[0071] (10) Nitrate reductase (Nar) activity: Under anaerobic conditions, the biofilm sample was mixed with nitrate substrate buffer, and the amount of nitrite generated was measured after a certain reaction time to calculate the enzyme activity.

[0072] Table 1

[0073] As shown in Table 1, the total nitrogen (TN) removal rate increased significantly from 45% (Comparative Example 1) to 88% (Example 1). The effluent NH4-N and NO3-N concentrations in Example 1 decreased to 0.1 mg / L and 0.5 mg / L, respectively, indicating that both nitrification and denitrification processes were nearing completion. This demonstrates that the functionalized biofilm of this invention effectively relieves the inhibitory toxicity of phenols and Cd(II) on the core denitrifying bacteria.

[0074] The removal rates of phenolic compounds and Cd(II) increased from 65% (Comparative Example 1) and 70% (Comparative Example 1) to 97.6% (Example 1) and 99.5% (Example 1), respectively, achieving a qualitative leap from "preliminary reduction" to "near removal". The effluent concentration was extremely low, better than the discharge standards.

[0075] In Example 1, the content of EPS protein and polysaccharide was significantly increased, forming a stronger physical barrier and adsorption sites; the activities of key enzymes AMO and Nar increased by more than 140%, confirming the enhanced denitrification function; and laccase activity (58 U / L) was successfully induced, obtaining a novel ability to degrade organic toxins.

[0076] 2. The following tests were conducted on Example 2 and Comparative Example 2, and the results are summarized in Table 2.

[0077] (1) Ammonia nitrogen (NH4-N) concentration: Same as above.

[0078] (2) NH4-N removal rate: Under acidic conditions, hexavalent chromium reacts with diphenylcarbazide to form a purple-red compound, and the absorbance is measured at a wavelength of 540 nm.

[0079] (3) Total chromium concentration: The water sample was digested with nitric acid-potassium permanganate to oxidize all the chromium to hexavalent chromium, and then the concentration was determined according to the hexavalent chromium method.

[0080] (4) COD removal rate: In a strong acid medium, potassium dichromate is used to oxidize the reducing substances in the water sample, and the amount of oxidant consumed is determined by titration or photometry.

[0081] (5) Total EPS: The protein and polysaccharide contents were determined by the Bradford method and the phenol-sulfuric acid method, respectively, and the total EPS was obtained by summing them.

[0082] (6) Adsorption capacity of Cr(VI): A certain amount of biofilm was reacted with a Cr(VI) solution of known concentration until equilibrium was reached, and the Cr(VI) concentration of the supernatant was measured after centrifugation.

[0083] Adsorption capacity (qe) = (initial concentration - equilibrium concentration) × volume / biofilm mass.

[0084] (7) Nitroreductase activity: Under anaerobic conditions, the biofilm sample was mixed with nitrobenzene substrate buffer, and the rate of nitrite formation or the rate of decrease in absorbance of nitrobenzene at a specific wavelength was monitored.

[0085] (8) Ammonia oxidation activity (AOA): Take a fresh biofilm sample and place it in a buffer solution containing a certain concentration of ammonium salt for reaction. Take a sample per unit time to measure the amount of ammonium salt reduction and calculate the ammonia oxidation rate.

[0086] As shown in Table 2, the ammonia nitrogen removal rate increased significantly from 43.8% (Comparative Example 2) to 98.8% (Example 2); the Cr(VI) removal rate increased from 60% (Comparative Example 2) to 99.3% (Example 2), and the total chromium concentration decreased to 0.05 mg / L (Example 2); the COD removal rate increased from 65% (Comparative Example 2) to over 90% (Example 2), achieving synergistic deep purification of multiple pollutants.

[0087] In Example 2, the total amount of EPS in the biofilm increased by 68%, providing more protection and adsorption sites; the specific adsorption capacity for Cr(VI) increased by 150% (reaching 45 mg / g VSS); and the activity of the key enzyme nitroreductase jumped 5 times (25 U / L), which is the direct reason why Cr(VI) was efficiently reduced to the low-toxicity Cr(III).

[0088] The ammonia oxidation activity (AOA) increased threefold, demonstrating that the activity of the core nitrifying bacteria community was effectively protected and enhanced. The functionalized biofilm successfully resisted the inhibitory effects of coexisting antibiotics and heavy metals in the wastewater, ensuring the efficient and stable operation of the system.

[0089] Table 2

[0090] 3. The following tests were conducted on Example 3 and Comparative Example 3, and the results are summarized in Table 3.

[0091] (1) Ammonia nitrogen (NH4-N) concentration, total nitrogen (TN) concentration, COD concentration, and laccase activity: same as the above methods.

[0092] (2) BPA removal rate: After the water sample was enriched by solid phase extraction, it was determined by high performance liquid chromatography.

[0093] (3) Sludge volume index: Take 1L of mixed liquid into a graduated cylinder, let it settle for 30 minutes, and record the volume of settled sludge (mL).

[0094] SVI = Settled sludge volume (mL / L) / MLSS (g / L).

[0095] (4) Peroxidase activity: horseradish peroxidase (HRP) is often used as a reference. In the presence of hydrogen peroxide, a specific substrate (o-phenylenediamine) is used to develop color and measure the change in absorbance.

[0096] (5) Nitrification / denitrification rate: Take activated sludge samples, add specific substrates (NH4⁺ or NO3⁻) to the batch reactor, and calculate the maximum specific degradation rate by monitoring the changes in dissolved oxygen (nitrification) or nitrogen oxide concentration (denitrification) over time online.

[0097] (6) Adsorption capacity of BPA: A certain amount of sludge was reacted with a BPA solution of known concentration until equilibrium was reached. After centrifugation, the supernatant was taken and the BPA concentration was determined by HPLC.

[0098] Adsorption capacity (qe) = (initial concentration - equilibrium concentration) × volume / sludge dry weight.

[0099] Table 3

[0100] As shown in Table 3, Example 3 achieved efficient removal of BPA (>97.5%) while maintaining effluent NH4-N <1 mg / L, TN <12 mg / L, and COD <40 mg / L. All indicators consistently met the discharge standards, demonstrating the synergistic purification capability.

[0101] Example 3 showed a significant improvement in sludge settling properties (SVI decreased from 95 to 75 mL / g), effectively reducing the risk of sludge runoff from the secondary settling tank. It induced the production of laccase (15 U / L) and peroxidase (8 U / L) activities, giving the system a novel function of directly degrading recalcitrant organic compounds such as BPA.

[0102] In Example 3, the nitrification and denitrification rates increased by approximately 29% and 25%, respectively, demonstrating enhanced activity of denitrifying microorganisms. The sludge's adsorption capacity for BPA doubled (reaching 5.0 mg / g VSS), achieving a highly efficient synergy between "rapid adsorption and enrichment" and "in-situ enzymatic degradation."

[0103] In summary, this invention provides a synergistic nutrient agent for nitrification / denitrification bacteria and its application, successfully resolving the core contradiction in traditional processes where "denitrification" and "detoxification" are difficult to coordinate in treating wastewater containing inhibitory pollutants. Through verification in three mainstream processes—MBBR, biological filter, and A / A / O—this invention demonstrates deep purification, enhanced functionality, and system stability.

Claims

1. A synergistic nutrient agent, characterized in that, The synergistic nutrient contains a component that enhances the high-efficiency adsorption of pollutants and a component that constructs in-situ catalytic degradation activity. The pollutant adsorption enhancement component is selected from zinc-cysteine ​​complex or manganese-citrate complex, chitosan oligosaccharide or quaternized chitosan oligosaccharide with an average degree of polymerization of 5, short peptides rich in glutamic acid and aspartic acid or short peptides rich in phenylalanine and tyrosine, and a mixture of L-glutamic acid and glutamic acid dipeptide. The in-situ catalytic degradation active building blocks are selected from microencapsulated copper-glycine complexes, riboflavin or heme, combinations of ferrous salts and citric acid, and hydrolyzable titanium salts and polyvinylpyrrolidone.

2. The synergistic nutrient agent according to claim 1, characterized in that, The high-efficiency adsorption enhancement components for pollutants are zinc-cysteine ​​complex, chitosan oligosaccharide with an average degree of polymerization of 5, and short peptides rich in glutamic acid and aspartic acid; the in-situ catalytic degradation active building components are copper-glycine complex, and a combination of ferrous sulfate and citric acid.

3. The synergistic nutrient agent according to claim 1, characterized in that, The high-efficiency adsorption enhancement components for pollutants are manganese-citrate complex, quaternized chitosan oligosaccharide, and polyγ-glutamic acid precursor; the in-situ catalytic degradation active building components are riboflavin, isopropyl titanate-ethanol, and polyvinylpyrrolidone.

4. The application of the synergistic nutrient agent as described in claim 1 in enhancing biological denitrification and co-removal of pollutants in wastewater, characterized in that, The synergistic nutrient is added to the bioreactor of the wastewater biological treatment system to construct a functionalized biofilm; the functionalized biofilm simultaneously achieves biological denitrification and adsorption and degradation of heavy metals and organic toxins.

5. The application according to claim 4, characterized in that, The functionalized biomembrane can adsorb and degrade exogenous inhibitory pollutants in situ.

6. The application according to claim 5, characterized in that, The exogenous inhibitory pollutants include one or more of cadmium, hexavalent chromium, phenolic compounds, bisphenol A, and antibiotic intermediates.

7. The application according to claim 4, characterized in that, The dosing method is either continuous dosing or pulsed intermittent dosing.

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