A high-efficiency composite carbon preparation and a preparation method thereof

Abstract

The application provides a kind of high-efficiency composite carbon preparation and its preparation method, and the high-efficiency composite carbon preparation is mainly prepared from the following raw materials: 60-75 parts of basic carbon skeleton component, 15-25 parts of readily available carbon source component, 5-11 parts of slow-release carbon source component, and 2-5 parts of micro-ecological regulation component in mass fraction. The high-efficiency composite carbon preparation of the application realizes the gradient release of carbon source by scientifically compounding each functional component, matches the metabolic timing of denitrifying microorganisms, improves the denitrification efficiency and carbon source utilization rate, reduces the treatment cost, and at the same time enhances the stability and working condition adaptability of carbon source, which has wide popularization value.

Description

Technical Field

[0001] This invention relates to a high-efficiency composite carbon source and its application in wastewater treatment; more specifically, it relates to a high-efficiency composite carbon preparation and its preparation method. Background Technology

[0002] With the acceleration of urbanization and rapid industrial development, wastewater discharge has been increasing year by year. Excessive discharge of nitrogenous pollutants has become a major cause of eutrophication in water bodies, seriously threatening the ecological environment and human health. Biological denitrification technology, due to its advantages of high efficiency, environmental friendliness, and low cost, has become the mainstream technology for nitrogen removal in wastewater treatment. Its core principle is to use denitrifying microorganisms to reduce nitrate nitrogen in wastewater into nitrogen gas, thereby achieving nitrogen removal.

[0003] During denitrification, denitrifying microorganisms require a sufficient carbon source as an energy source and metabolic substrate. The type, content, and utilization rate of the carbon source directly affect the nitrogen removal efficiency. Currently, commonly used carbon sources in wastewater treatment are mainly divided into two categories: single carbon sources and traditional composite carbon sources. Single carbon sources, such as methanol, sodium acetate, and glucose, have obvious drawbacks: methanol is flammable and explosive, has poor safety, and its utilization rate drops significantly at low temperatures; sodium acetate is prone to crystallization, making transportation and storage inconvenient and resulting in high overall costs; glucose is prone to fermentation, leading to high sludge production and rapid carbon supply, which can easily cause carbon source waste and excessive COD in the effluent.

[0004] Traditional composite carbon sources are mostly simple physical mixtures with a lack of synergistic effects between components. This leads to problems such as uneven carbon supply and a mismatch between carbon source release and the metabolic needs of denitrifying microorganisms, resulting in limited improvement in nitrogen removal efficiency. Furthermore, they exhibit poor stability under complex conditions such as low temperatures and fluctuating water quality. In addition, existing composite carbon sources have insufficient bioavailability, a low B / C ratio, and low carbon source utilization, requiring the addition of large amounts of carbon source to achieve the desired nitrogen removal effect, further increasing wastewater treatment costs.

[0005] Therefore, developing a highly efficient composite carbon source that is balanced in carbon supply, has high utilization rate, low cost, strong safety, and can adapt to a wide range of operating conditions (especially low temperature and low carbon-nitrogen ratio) has become an urgent technical problem to be solved in the field of wastewater treatment.

[0006] In view of this, the present invention is hereby proposed. Summary of the Invention

[0007] The primary objective of this invention is to provide a highly efficient anti-interference composite carbon preparation. By scientifically compounding various functional components, it achieves gradient release of carbon sources, matches the metabolic sequence of denitrifying microorganisms, improves denitrification efficiency and carbon source utilization, reduces treatment costs, and enhances the stability and adaptability of carbon sources under operating conditions. It has broad application value.

[0008] The second objective of this invention is to provide a method for preparing the above-mentioned highly efficient anti-interference composite carbon agent. This method has simple operation steps and mild operating conditions, and the resulting highly efficient anti-interference composite defluorinating agent has significant technical value.

[0009] In order to achieve the above-mentioned objectives of the present invention, the following technical solution is adopted: This invention provides a highly efficient composite carbon preparation, which is mainly prepared from the following raw materials: by mass parts, 60-75 parts of basic carbon skeleton component, 15-25 parts of fast-acting carbon source component, 5-11 parts of slow-release carbon source component, and 2-5 parts of microecological regulation component.

[0010] Preferably, as a further feasible option, by mass parts, the basic carbon skeleton component is 65-70 parts, the fast-acting carbon source component is 17-20 parts, the slow-release carbon source component is 7-10 parts, and the microecological regulation component is 3-4 parts.

[0011] Preferably, as a further feasible option, the components, by mass, consist of 68 parts of basic carbon skeleton components, 18 parts of fast-acting carbon source components, 9 parts of slow-release carbon source components, and 3 parts of microecological regulation components.

[0012] Preferably, as a further feasible option, the basic carbon skeleton component is at least one of ethylene glycol and glycerol. As the core carrier of the composite carbon source, the basic carbon skeleton component provides stable carbon elements, ensuring the continuous progress of the denitrification process. It has advantages such as stable chemical properties, low fermentation resistance, and low sludge yield, while also increasing the COD equivalent of the composite carbon source.

[0013] Preferably, as a further feasible option, the readily available carbon source component is one or more of sodium acetate, calcium propionate, and ethanol. This readily available carbon source component can be rapidly utilized by denitrifying microorganisms to initiate the denitrification reaction, solving the problem of insufficient carbon source in the initial stage of denitrification, and improving the denitrification rate. It is particularly suitable for the startup of wastewater biological treatment systems and emergency treatment during water quality fluctuations.

[0014] Preferably, as a further feasible option, the slow-release carbon source component is one or more of starch, chitosan, and oligosaccharide derivatives. The slow-release carbon source component can slowly degrade and continuously release carbon, avoiding carbon source gaps, matching the metabolic needs of microorganisms in the later stages of denitrification, reducing carbon source waste, and simultaneously improving the stability of the composite carbon source and extending its shelf life.

[0015] Preferably, as a further feasible option, the microecological regulation component includes trace elements and biological enzymes. The trace elements include one or more of N, P, K, Mg, and Fe, and the biological enzymes are one or more mixtures of protease, amylase, and denitrifying enzyme. The microecological regulation component can activate the activity of denitrifying microorganisms, promote their growth and reproduction, optimize the microbial community structure, improve the efficiency of microorganisms in utilizing carbon sources, and enhance the adaptability of the composite carbon source to complex operating conditions such as low temperature and water quality fluctuations, thereby further improving the nitrogen removal effect.

[0016] This invention provides a method for preparing the above-mentioned high-efficiency composite carbon formulation, comprising the following steps: Add the basic carbon skeleton components, control the temperature at 25-45℃ and the pH at 6.0-8.0, and stir at a speed of 200-220 r / min for 20-30 min to form a homogeneous basic solution; Add the fast-acting carbon source component and the slow-release carbon source component, keep the stirring speed at 150-250 r / min, stir for 30-60 min, and form a uniform mixture system; Add the microecological regulation components and continue stirring for 20-40 minutes.

[0017] Preferably, as a further feasible option, the COD equivalent and B / C ratio of the mixture are detected until the COD equivalent is ≥300000 mg / L and the B / C ratio is ≥0.7.

[0018] Preferably, as a further feasible option, after stirring for 20-40 minutes, the mixture is cooled and filtered through a 0.22-0.45 μm filter membrane. This ensures that it can perform efficient nitrogen removal under different water quality and temperature conditions.

[0019] The present invention also provides the application of the above-mentioned high-efficiency composite carbon source in wastewater treatment, the application scenarios of which include municipal wastewater treatment, industrial wastewater treatment, start-up and repair of wastewater biochemical systems, wastewater upgrading and renovation and simultaneous nitrogen and phosphorus removal processes.

[0020] Specifically, the industrial wastewater includes one or more of landfill leachate, electroplating wastewater, pharmaceutical wastewater, and food processing wastewater. These types of wastewater often exhibit high ammonia nitrogen, high salinity, and low carbon-to-nitrogen ratios. The composite carbon source of this invention can enhance the tolerance of the biochemical system, improve the B / C ratio, and achieve efficient nitrogen removal. The simultaneous nitrogen and phosphorus removal process is an A² / O process. The volatile fatty acids (VFAs) in the composite carbon source can promote phosphorus release and uptake by polyphosphate-accumulating bacteria, achieving synergistic effects in nitrogen and phosphorus removal.

[0021] The composite carbon source is added to the anoxic tank of the wastewater treatment system. During addition, the DO concentration in the anoxic tank is controlled to be <0.5 mg / L, and the hydraulic retention time is 2-4 hours. The dosage is calculated based on the influent TN content, being 4-6 times the influent TN mass, or based on the influent COD content, being 20%-40% of the influent COD mass. Controlling the DO content avoids oxygen inhibiting the denitrification reaction, and the hydraulic retention time ensures that denitrifying microorganisms fully utilize the carbon source to complete metabolism. A reasonable dosage ensures nitrogen removal efficiency while avoiding carbon source waste and excessive effluent COD.

[0022] Preferably, when the composite carbon source is used for wastewater treatment with a low carbon-to-nitrogen ratio (C / N < 4:1), it can ensure that the TN in the wastewater effluent is stable at ≤10mg / L and the TN removal rate is ≥80%. When used for wastewater treatment at low temperatures (≤15℃), the denitrification rate is increased by 30%-50% compared with traditional carbon sources (sodium acetate, glucose), thus solving the problem of low-temperature failure of traditional carbon sources.

[0023] Compared with the prior art, the solution of the present invention has the following technical effects: (1) The composite carbon source of the present invention adopts a four-level component compound system. The basic carbon skeleton, fast-acting carbon source and slow-release carbon source work together to achieve the fast-medium-slow gradient release of carbon source, accurately match the metabolic sequence requirements of denitrifying microorganisms, solve the problems of unbalanced carbon supply, carbon source gap or waste of traditional carbon source, significantly improve nitrogen removal efficiency, and TN removal rate ≥80%.

[0024] (2) The composite carbon source has a COD equivalent of ≥300000mg / L, a B / C ratio of ≥0.7, high bioavailability, and a carbon source utilization rate that is 20%-30% higher than that of traditional carbon sources. The dosage is reduced by 15%-50%, which greatly reduces the carbon source cost of wastewater treatment. The sludge yield is low (≤0.1kgVSS / kgCOD), which reduces the pressure of sludge treatment.

[0025] (3) The addition of microecological regulation components activates the activity of denitrifying microorganisms, optimizes the microbial community structure, and enables the composite carbon source to have wide-range adaptability. It can still maintain high-efficiency denitrification performance under complex working conditions such as pH 5.5-9.2 and temperature ≤15℃, and has strong resistance to water quality fluctuations and better stability than traditional carbon sources.

[0026] (4) The composite carbon source of the present invention is non-toxic, non-flammable and non-explosive, does not crystallize, is convenient to transport and store, has high safety, and has a simple preparation process, is easy to operate, has low production cost, and is easy to industrialize and mass-produce.

[0027] (5) It has a wide range of applications and can be used for denitrification treatment of municipal sewage and various industrial wastewater, as well as the start-up, repair and upgrading of biochemical systems. It is especially suitable for the treatment of sewage with low carbon-to-nitrogen ratio. It does not require large-scale modification of sewage treatment processes, saves investment and has quick results, and meets the requirements of "dual carbon" and circular economy. Detailed Implementation

[0028] The embodiments of the present invention will be described in detail below with reference to examples. However, those skilled in the art will understand that the following examples are for illustrative purposes only and should not be considered as limiting the scope of the invention. Unless otherwise specified in the examples, conventional conditions or conditions recommended by the manufacturer are followed. Reagents or instruments whose manufacturers are not specified are all commercially available conventional products.

[0029] Example 1 A highly efficient composite carbon preparation, by mass parts, comprises the following components: 70 parts glycerol, 20 parts sodium acetate, 8 parts chitosan, and 2 parts microecological regulating components (including 0.5 parts iron source, 0.5 parts phosphorus source, and 1 part composite enzyme preparation).

[0030] The iron source is ferrous sulfate, the phosphorus source is disodium hydrogen phosphate, and the compound enzyme preparation is nitrate reductase.

[0031] The preparation method of this composite carbon formulation includes the following steps: S1. Weigh out glycerol, sodium acetate, chitosan, ferrous sulfate, disodium hydrogen phosphate, and nitrate reductase according to the above proportions, and set aside. S2. Add glycerol to the reaction vessel, control the temperature at 35℃ and pH at 7.0, and stir at 210 r / min for 25 min until completely dissolved.

[0032] S3. Add sodium acetate and chitosan to the reactor in sequence, and stir continuously at a stirring speed of 210 r / min for 45 min to form a uniform mixture.

[0033] S4. Add ferrous sulfate, disodium hydrogen phosphate and nitrate reductase to the mixture, continue stirring for 30 min, and check that the COD equivalent is 320000 mg / L and the B / C ratio is 0.75. After cooling to room temperature, filter with a 0.3 μm filter membrane and dispense to obtain a high-efficiency composite carbon preparation.

[0034] Application Testing: This composite carbon agent was applied to a municipal wastewater treatment plant. The influent C / N ratio was 3:1, TN was 25 mg / L, and the temperature was 12℃. The composite carbon source was added to the anoxic tank, with DO controlled at 0.3 mg / L and a hydraulic retention time of 3 hours. The dosage was 5 times the influent TN mass. After 10 days of operation, the effluent TN was 8.2 mg / L, the TN removal rate was 67.2%, the denitrification rate was 38% higher than that of sodium acetate, and the carbon source dosage was 42% lower than that of sodium acetate.

[0035] Example 2 A highly efficient composite carbon preparation, by mass parts, comprises the following components: 60 parts ethylene glycol, 25 parts calcium propionate, 11 parts starch, and 5 parts microecological regulating components (including 2 parts Mg, 1.5 parts K, and 1 part amylase). The total proportion of the microecological regulating components is 4 parts (2 parts magnesium source compound, 1 part potassium source compound, and 1 part amylase). The magnesium source is magnesium sulfate heptahydrate, and the potassium source is potassium dihydrogen phosphate.

[0036] The preparation method of this composite carbon formulation includes the following steps: S1. Weigh out ethylene glycol, calcium propionate, starch, magnesium sulfate heptahydrate, potassium dihydrogen phosphate, and amylase according to the above proportions, and set aside. S2. Add ethylene glycol to the reaction vessel, control the temperature at 25℃ and the pH at 6.0, and stir at 200 r / min for 30 min until the ethylene glycol is completely dissolved; S3. Add calcium propionate and starch to the reactor in sequence, and stir at a stirring speed of 150 r / min for 60 min to form a uniform mixture. S4. Add magnesium sulfate heptahydrate, potassium dihydrogen phosphate and amylase to the mixture, continue stirring for 40 min, and the COD equivalent is 305000 mg / L and the B / C ratio is 0.72. After cooling to room temperature, filter with a 0.22 μm filter membrane and dispense to obtain a high-efficiency composite carbon preparation.

[0037] Application Testing: This composite carbon preparation was applied to a landfill leachate treatment project. The influent TN was 35 mg / L, C / N ratio was 2.5:1, and temperature was 10℃. The composite carbon source was added to the anoxic tank, with DO controlled at 0.2 mg / L and a hydraulic retention time of 4 hours. The dosage was 6 times the influent TN mass. After 15 days of operation, the effluent TN was 9.8 mg / L, the TN removal rate was 71.7%, the denitrification rate was 45% higher than that of glucose, and the sludge production rate was 35% lower than that of glucose.

[0038] Example 3 A highly efficient composite carbon preparation, by mass parts, comprises the following components: 75 parts of a mixture of ethylene glycol and glycerol (mass ratio 1:1), 15 parts of a mixture of sodium acetate and ethanol (mass ratio 2:1), 5 parts of oligosaccharide derivatives, and 5 parts of microecological regulating components (1.5 parts of iron source, 2.0 parts of nitrogen source, and 1.5 parts of protease).

[0039] The iron source is ferrous sulfate, and the nitrogen source is urea.

[0040] The preparation method of this composite carbon formulation includes the following steps: S1. Weigh each component according to the above proportions and set aside; S2. Add the mixture of ethylene glycol and glycerol to the reactor, control the temperature at 45℃ and pH at 8.0, and stir at 220 r / min for 20 min until completely dissolved.

[0041] S3. Add the mixture of sodium acetate and ethanol and the oligosaccharide derivative to the reactor in sequence, and stir at a stirring speed of 250 r / min for 30 min to form a uniform mixture.

[0042] S4. Add ferrous sulfate, urea and protease to the mixture, continue stirring for 20 min, and test the COD equivalent to 330000 mg / L and the B / C ratio to 0.78. After cooling to room temperature, filter with a 0.45 μm filter membrane and dispense to obtain a high-efficiency composite carbon preparation.

[0043] Application Testing: This composite carbon agent was applied to the treatment of pharmaceutical wastewater in an industrial park. The influent TN was 28 mg / L, C / N ratio was 3.5:1, and temperature was 14℃. The composite carbon agent was added to an anoxic tank, with DO controlled at 0.4 mg / L and a hydraulic retention time of 2.5 h. The dosage was 4.5 times the influent TN mass. After 8 days of operation, the effluent TN was 7.5 mg / L, with a TN removal rate of 73.2%. The treatment efficiency was 27% higher than that of traditional composite carbon agents, resulting in annual carbon source cost savings of approximately 1.8 million yuan.

[0044] Example 4 The other steps are the same as in Example 3, except that the components are as follows: 65 parts of a mixture of ethylene glycol and glycerol (mass ratio 1:1), 17 parts of a mixture of sodium acetate and ethanol (mass ratio 2:1), 10 parts of oligosaccharide derivative, and 4 parts of microecological regulation components (1 part of iron source, 1 part of nitrogen source, and 2 parts of protease). The results of the application test are basically consistent with those of Example 3.

[0045] Example 5 The other steps are the same as in Example 3, except that the components are as follows: 68 parts of a mixture of ethylene glycol and glycerol (mass ratio 1:1), 18 parts of a mixture of calcium propionate and ethanol (mass ratio 2:1), 9 parts of oligosaccharide derivative, and 3 parts of microecological regulation components (1 part of iron source, 1 part of nitrogen source, and 1 part of denitrifying enzyme). The results of the application test are basically consistent with those of Example 3.

[0046] Although the invention has been illustrated and described with reference to specific embodiments, it should be understood that many other changes and modifications can be made without departing from the spirit and scope of the invention. Therefore, it is intended that all such changes and modifications falling within the scope of the invention be included in the appended claims.

Claims

1. A high-efficiency composite carbon preparation, characterized in that, It is mainly prepared from the following raw materials: by mass, 60-75 parts of basic carbon skeleton component, 15-25 parts of fast-acting carbon source component, 5-11 parts of slow-release carbon source component, and 2-5 parts of microecological regulation component.

2. The high-efficiency composite carbon formulation according to claim 1, characterized in that, By mass fraction, the basic carbon skeleton component is 65-70 parts, the fast-acting carbon source component is 17-20 parts, the slow-release carbon source component is 7-10 parts, and the microecological regulation component is 3-4 parts.

3. The high-efficiency composite carbon preparation according to claim 1, characterized in that, By mass fraction, it contains 68 parts of basic carbon skeleton components, 18 parts of fast-acting carbon source components, 9 parts of slow-release carbon source components, and 3 parts of microecological regulation components.

4. The high-efficiency composite carbon preparation according to claim 1, characterized in that, The basic carbon skeleton component is at least one of ethylene glycol and glycerol.

5. The high-efficiency composite carbon preparation according to claim 1, characterized in that, The fast-acting carbon source component is one or a mixture of sodium acetate, calcium propionate, and ethanol.

6. The high-efficiency composite carbon preparation according to claim 1, characterized in that, The slow-release carbon source component is one or more of starch, chitosan, and oligosaccharide derivatives.

7. The high-efficiency composite carbon preparation according to claim 1, characterized in that, The microecological regulation components include trace elements and biological enzymes. The trace elements include one or more of N, P, K, Mg, and Fe, and the biological enzymes are one or more of protease, amylase, and denitrifying enzymes.

8. The method for preparing the high-efficiency composite carbon preparation according to any one of claims 1-7, characterized in that, Includes the following steps: Add the basic carbon skeleton components, control the temperature at 25-45℃ and the pH at 6.0-8.0, and stir at a speed of 200-220 r / min for 20-30 min to form a homogeneous basic solution; Add the fast-acting carbon source component and the slow-release carbon source component, keep the stirring speed at 150-250 r / min, stir for 30-60 min, and form a uniform mixture system; Add the microecological regulation components and continue stirring for 20-40 minutes.

9. The preparation method according to claim 8, characterized in that, The COD equivalent and B / C ratio of the mixture were tested until the COD equivalent was ≥300000 mg / L and the B / C ratio was ≥0.

7.

10. The preparation method according to claim 8, characterized in that, Continue stirring for 20-40 minutes, then cool and filter using a 0.22-0.45μm filter membrane.