A production process for preparing a composite carbon source by utilizing fruit and vegetable waste resources

Abstract

The application discloses a production process for preparing composite carbon source by utilizing fruit and vegetable waste resources, and comprises the following steps: raw material pretreatment, anaerobic fermentation for acid production, composite enzymolysis, deep solid-liquid separation, composite blending, and stabilization treatment; the blending carbon source liquid is pumped into the stabilization treatment tank, 0.1%-0.3% of a compounded stabilizer is added, the pH value is adjusted to 6.0-7.0, normal-temperature standing is carried out for 12-24 hours, product detection and storage are carried out, the carbon source product after the stabilization treatment is detected in terms of COD, total nitrogen, total phosphorus, the pH value and the content of small-molecule organic acid, and after each index is qualified, the product is sealed and packaged and stored in a cool and dry environment, and the application solves the technical problems of high cost, poor safety, single fruit and vegetable base carbon source component, low degradation efficiency and poor product stability of traditional carbon sources.

Description

Technical Field

[0001] This invention relates to the technical field of carbon source preparation, and in particular to a production process for preparing composite carbon sources using fruit and vegetable waste resources. Background Technology

[0002] In the biological treatment stage of wastewater treatment, denitrification is the core process for removing nitrogenous pollutants from water bodies, and the addition of an external carbon source is a key means to ensure the efficient metabolism of denitrifying bacteria and improve the total nitrogen removal effect. Currently, the carbon sources commonly used in the wastewater treatment industry are mainly single carbon sources such as sodium acetate, methanol, and glucose. These carbon sources have obvious drawbacks: methanol is a flammable and explosive hazardous material, posing high safety risks during transportation, storage, and use, and it also has a certain degree of toxicity to microorganisms; sodium acetate and glucose carbon sources have a single composition, and the carbon-nitrogen-phosphorus ratio is difficult to match the metabolic needs of microorganisms, resulting in limited denitrification efficiency. At the same time, their procurement costs remain high, significantly increasing the operating costs of wastewater treatment.

[0003] Meanwhile, the entire process of fruit and vegetable planting, processing, and distribution generates a massive amount of waste. Defective fruits, peels, vegetable leaves, and processing byproducts are easily perishable and deteriorate. If discarded haphazardly or simply landfilled, they will not only pollute soil and water bodies but also lead to a significant waste of organic resources. Fruit and vegetable waste is rich in biodegradable organic matter such as sugars, cellulose, pectin, and starch, making it a high-quality natural raw material for preparing biocarbon sources. Using it in the production of composite carbon sources can both realize the resource utilization of agricultural solid waste and reduce carbon source production costs, possessing significant economic and environmental value.

[0004] Existing processes for preparing fruit and vegetable-based carbon sources still suffer from numerous technical shortcomings: they often employ single fermentation or enzymatic hydrolysis processes, resulting in insufficient degradation of macromolecular organic matter, low content of effective small-molecule carbon sources, and low COD concentrations in the products; process parameter control is rudimentary, leading to unstable fermentation and enzymatic hydrolysis efficiencies and large fluctuations in product composition; there is a lack of targeted carbon source component formulation and stabilization treatment, resulting in an imbalance in the carbon, nitrogen, and phosphorus ratios, making it difficult to meet the precise requirements of denitrification in wastewater treatment; and incomplete solid-liquid separation leads to high impurity content in the products, making them prone to precipitation, deterioration, short storage periods, and poor ease of use. Therefore, developing a fruit and vegetable composite carbon source production process that is highly efficient, produces stable products, and optimizes carbon source components to address the pain points of existing technologies has become an urgent technical problem to be solved in this field. Summary of the Invention

[0005] This invention addresses the shortcomings of existing technologies by providing a production process for preparing composite carbon sources from fruit and vegetable waste. Through an integrated process encompassing raw material pretreatment, directional anaerobic fermentation, compound enzymatic hydrolysis, deep solid-liquid separation, precise compound formulation, and stabilization treatment, it achieves efficient resource utilization of fruit and vegetable waste. This process solves the technical problems of high cost, poor safety, single component in fruit and vegetable-based carbon sources, low degradation efficiency, and poor product stability associated with traditional carbon sources. The result is a composite carbon source with high COD concentration, balanced composition, and excellent denitrification and nitrogen removal effects.

[0006] To solve the above-mentioned technical problems, the present invention adopts a production process for preparing composite carbon sources using fruit and vegetable waste resources, comprising the following steps:

[0007] (1) Raw material pretreatment: Select fruit and vegetable waste, sort and remove impurities, wash and drain, then break it into pieces, press it under pressure, and separate the fruit and vegetable filtrate.

[0008] (2) Anaerobic fermentation to produce acid: Adjust the pH of the filtrate to 6.5-7.5 using an acid-base regulator, inoculate with 3%-5% compound fermentation agent, and anaerobic ferment for 5-8 days, stirring 2-3 times a day for 30-40 minutes each time to obtain fermentation liquid;

[0009] (3) Compound enzymatic hydrolysis: Add 0.2%-0.4% compound enzyme preparation to the fermentation broth, adjust the temperature to 45-55℃ and pH to 5.0-6.5, and enzymatically hydrolyze for 2-4 hours to obtain the enzymatic hydrolysate;

[0010] (4) Deep solid-liquid separation: The enzymatic hydrolysate is centrifuged at 4000-6000 r / min and filtered through a 0.1-0.5 μm microfiltration membrane to obtain a clear carbon source mother liquor;

[0011] (5) Compound preparation: Add 5%-10% compound supplement carbon source to the carbon source mother liquor, adjust the COD concentration to 120,000-180,000 mg / L, carbon-nitrogen ratio (20-25):1, carbon-phosphorus ratio (150-200):1, and obtain the prepared carbon source solution;

[0012] (6) Stabilization treatment: Pump the prepared carbon source solution into the stabilization treatment tank, add 0.1%-0.3% compound stabilizer, adjust the pH to 6.0-7.0, and let it stand at room temperature for 12-24 hours;

[0013] (7) Finished product testing and storage: The carbon source product after stabilization treatment is tested for COD, total nitrogen, total phosphorus, pH value and small molecule organic acid content. After all indicators are qualified, it is sealed and packaged and stored in a cool and dry environment.

[0014] In a preferred embodiment of the present invention, in step (1), the particle size of the crushed particles after washing and draining is 0.5-1.5cm, and the pressing process is carried out under a pressure of 0.8-1.2MPa.

[0015] In a preferred embodiment of the present invention, in step (2), the anaerobic fermentation temperature of the compound fermentation agent is 35-38℃.

[0016] In a preferred embodiment of the present invention, in step (2), the compound fermentation agent is Klebsiella acidogenic, Lactobacillus plantarum, and Bacillus subtilis.

[0017] In a preferred embodiment of the present invention, the Klebsiella acidogenic bacteria, Lactobacillus plantarum, and Bacillus subtilis are compounded in a mass ratio of 2:1:1, and the effective viable count is ≥1×10^9 CFU / g.

[0018] In a preferred embodiment of the present invention, in step (2), the acid-base regulator is food-grade citric acid or sodium hydroxide.

[0019] In a preferred embodiment of the present invention, in step (3), the compound enzyme preparation is cellulase, pectinase and amylase, and the cellulase, pectinase and amylase are compounded in an enzyme activity ratio of 3:2:1.

[0020] In a preferred embodiment of the present invention, the cellulase activity is ≥50000 U / g, the pectinase activity is ≥30000 U / g, and the amylase activity is ≥40000 U / g.

[0021] In a preferred embodiment of the present invention, in step (5), the compound supplementary carbon source is food-grade sodium acetate, glucose and glycerol, which are mixed in a mass ratio of 2:3:1, and the purity of each raw material is ≥98%.

[0022] In a preferred embodiment of the present invention, in step (6), the compound stabilizer is sodium citrate and sodium alginate, and the sodium citrate and sodium alginate are compounded in a mass ratio of 1:1.

[0023] The beneficial effects of this invention are: through an integrated process of raw material pretreatment, directional anaerobic fermentation, compound enzymatic hydrolysis, deep solid-liquid separation, precise compound formulation, and stabilization treatment, efficient resource utilization of fruit and vegetable waste is achieved. This solves the technical problems of high cost, poor safety, single component of fruit and vegetable-based carbon sources, low degradation efficiency, and poor product stability of traditional carbon sources. A composite carbon source with high COD concentration, balanced composition, and excellent denitrification effect is prepared. Detailed Implementation

[0024] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0025] This invention discloses a production process for preparing composite carbon sources using fruit and vegetable waste resources, comprising the following steps:

[0026] (1) Raw material pretreatment: Select fruit and vegetable waste as raw material, sort and remove non-organic impurities such as soil, sand, plastic, and metal, rinse with clean water to remove surface dirt, drain the surface free water, send it to the crusher to crush into fruit and vegetable pieces with a particle size of 0.5-1.5cm, and then press to separate solid and liquid by pressing. Control the pressing pressure to 0.8-1.2MPa to separate fruit and vegetable filtrate and filter residue. Collect the filtrate for later use.

[0027] (2) Anaerobic fermentation to produce acid: The pH of the filtrate is adjusted to 6.5-7.5 using an acid-base regulator. 3%-5% of compound fermentation agent is inoculated and anaerobic fermentation is carried out at 35-38℃ for 5-8 days. Stirring is performed 2-3 times a day for 30-40 minutes each time to obtain fermentation liquid. The compound fermentation agent is Klebsiella acid-producing bacteria, Lactobacillus plantarum and Bacillus subtilis, mixed in a mass ratio of 2:1:1, with an effective viable count ≥1×10^9 CFU / g. The acid-base regulator is food-grade citric acid or sodium hydroxide. The compound enzyme preparation is cellulase, pectinase and amylase. The cellulase, pectinase and amylase are mixed in an enzyme activity ratio of 3:2:1. The cellulase activity is ≥50000U / g, the pectinase activity is ≥30000U / g, and the amylase activity is ≥40000U / g.

[0028] (3) Compound enzymatic hydrolysis: Add 0.2%-0.4% compound enzyme preparation to the fermentation broth, adjust the temperature to 45-55℃ and pH to 5.0-6.5, and enzymatically hydrolyze for 2-4 hours to obtain the enzymatic hydrolysate;

[0029] (4) Deep solid-liquid separation: The enzymatic hydrolysate is centrifuged at 4000-6000 r / min and filtered through a 0.1-0.5 μm microfiltration membrane to obtain a clear carbon source mother liquor;

[0030] (5) Compound preparation: Add 5%-10% compound supplementary carbon source to the carbon source mother liquor to adjust the COD concentration to 120,000-180,000 mg / L, the carbon-nitrogen ratio to (20-25):1, and the carbon-phosphorus ratio to (150-200):1 to obtain the prepared carbon source solution. The compound supplementary carbon source is food-grade sodium acetate, glucose and glycerol. The food-grade sodium acetate, glucose and glycerol are mixed in a mass ratio of 2:3:1, and the purity of each raw material is ≥98%.

[0031] (6) Stabilization treatment: Pump the prepared carbon source solution into the stabilization treatment tank, add 0.1%-0.3% compound stabilizer, adjust the pH to 6.0-7.0, and let it stand at room temperature for 12-24 hours. The compound stabilizer is sodium citrate and sodium alginate, which are compounded in a mass ratio of 1:1.

[0032] (7) Finished product testing and storage: The carbon source product after stabilization treatment is tested for COD, total nitrogen, total phosphorus, pH value and small molecule organic acid content. After all indicators are qualified, it is sealed and packaged and stored in a cool and dry environment.

[0033] Example 1:

[0034] A production process for producing composite carbon sources using fruits and vegetables includes the following steps:

[0035] 1. Raw material pretreatment: Take a mixture of defective apples, banana peels, and cabbage stalks as fruit and vegetable waste, sort and remove impurities, rinse with clean water and drain, crush into 1cm pieces, and press with a press at 1.0MPa pressure to separate and obtain fruit and vegetable filtrate.

[0036] 2. Anaerobic fermentation for acid production: Pump the filtrate into an anaerobic fermenter, adjust the initial pH to 7.0, and inoculate with a 4% (w / w) compound fermentation agent, wherein the ratio of acid-producing Klebsiella: Lactobacillus plantarum: Bacillus subtilis = 2:1:1. Perform anaerobic fermentation at 37℃ in a sealed environment for 6 days, stirring twice a day for 30 minutes each time.

[0037] 3. Compound enzymatic hydrolysis: Add 0.3% by mass of compound enzyme preparation to the fermentation broth, wherein the ratio of cellulase:pectinase:amylase = 3:2:1, adjust the temperature to 50℃ and pH value to 6.0, and perform enzymatic hydrolysis at a constant temperature for 3 hours;

[0038] 4. Deep solid-liquid separation: The enzymatic hydrolysate was centrifuged at 5000 r / min and filtered through a 0.2 μm microfiltration membrane to obtain a clear carbon source mother liquor;

[0039] 5. Compound preparation: Add 8% compound supplementary carbon source (sodium acetate: glucose: glycerol = 2:3:1) to the mother liquor, stir well, and adjust the COD concentration to 150,000 mg / L, carbon-nitrogen ratio to 23:1, and carbon-phosphorus ratio to 180:1;

[0040] 6. Stabilization treatment: Add 0.2% compound stabilizer, adjust the pH value to 6.5, and let stand at room temperature for 18 hours;

[0041] 7. After passing the inspection, seal and store in a package.

[0042] Example 2

[0043] A production process for producing composite carbon sources using fruits and vegetables includes the following steps:

[0044] 1. Raw material pretreatment: Take grape pomace, tomato scraps, celery leaves and other mixed fruit and vegetable waste, sort and remove impurities, wash and drain, crush into 0.8cm pieces, and press under 0.9MPa pressure to obtain filtrate;

[0045] 2. Anaerobic fermentation to produce acid: Adjust the initial pH value to 6.8, inoculate with 3.5% compound fermentation agent, and anaerobic ferment at 36℃ in a sealed environment for 7 days, stirring twice a day for 30 minutes each time;

[0046] 3. Compound enzymatic hydrolysis: Add 0.25% compound enzyme preparation, adjust the temperature to 48℃ and pH value to 5.8, and enzymatically hydrolyze for 3.5 hours;

[0047] 4. Deep solid-liquid separation: Centrifugation at 4500 r / min and filtration through a 0.3 μm microfiltration membrane yielded the carbon source mother liquor;

[0048] 5. Compound formulation: Add 7% compound supplementary carbon source to adjust COD concentration to 140,000 mg / L, carbon-nitrogen ratio 22:1, carbon-phosphorus ratio 170:1;

[0049] 6. Stabilization treatment: Add 0.15% compound stabilizer, adjust the pH value to 6.3, and let stand at room temperature for 20 hours;

[0050] 7. After passing the inspection, seal and store in a package.

[0051] Performance comparison test

[0052] The composite carbon source prepared in Examples 1 and 2, along with the traditional sodium acetate carbon source, were applied to the same domestic wastewater treatment system for denitrification performance testing. The results are shown in the table below:

[0053] detection indicators Example 1 Example 2 Traditional sodium acetate carbon source COD concentration (mg / L) 152000 146000 80000 Small molecule organic acid content (%) 38.6 36.8 22.3 Total nitrogen removal rate in wastewater treatment (%) 96.2 95.7 88.5 Shelf life at room temperature (months) 6 6 3

[0054] Test results show that the composite carbon source prepared by the process of this invention has significantly better performance indicators than the traditional sodium acetate carbon source, with higher carbon source activity, better denitrification effect, and stronger stability.

[0055] The beneficial effects of this invention are:

[0056] (1) High efficiency and low cost of resource utilization: Using fruit and vegetable waste as the main raw material, the high-value utilization of agricultural solid waste is realized, waste pollution is reduced, and the cost of carbon source raw materials is significantly reduced. Compared with traditional single carbon source, the production cost is reduced by more than 30%, which has both environmental and economic benefits.

[0057] (2) High content of effective carbon source components and excellent denitrification effect: The anaerobic fermentation and compound enzymatic hydrolysis synergistic process is adopted to degrade the organic matter of fruits and vegetables in a targeted manner. The macromolecular substances are fully converted and the content of small molecule organic acids and soluble sugars is greatly increased. The product COD concentration reaches 120,000-180,000 mg / L. The carbon-nitrogen-phosphorus ratio is adapted to the metabolic needs of denitrifying bacteria. The total nitrogen removal rate of wastewater treatment is ≥95%, and the denitrification efficiency is significantly better than that of traditional carbon sources.

[0058] (3) The product has strong stability and is easy to use: all impurities are removed through deep solid-liquid separation to avoid product sedimentation and stratification. The compound stabilizer further improves the physical and chemical stability of the product. The product has a shelf life of more than 6 months, with no safety hazards. Transportation and addition are simple and suitable for various sewage treatment scenarios.

[0059] (4) The process is highly controllable and suitable for large-scale production: the process parameters are precise and controllable throughout the entire process, the process flow is simple and coherent, the equipment is highly versatile, no special high-end equipment is required, large-scale continuous production can be achieved, the product quality is stable, and no secondary pollution is generated.

[0060] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made based on the content of the present invention specification, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A production process for preparing composite carbon sources using fruit and vegetable waste resources, characterized in that, Includes the following steps: (1) Raw material pretreatment: Select fruit and vegetable waste, sort and remove impurities, wash and drain, then break it into pieces, press it under pressure, and separate the fruit and vegetable filtrate. (2) Anaerobic fermentation to produce acid: Adjust the pH of the filtrate to 6.5-7.5 using an acid-base regulator, inoculate with 3%-5% compound fermentation agent, and anaerobic ferment for 5-8 days, stirring 2-3 times a day for 30-40 minutes each time to obtain fermentation liquid; (3) Compound enzymatic hydrolysis: Add 0.2%-0.4% compound enzyme preparation to the fermentation broth, adjust the temperature to 45-55℃ and pH to 5.0-6.5, and enzymatically hydrolyze for 2-4 hours to obtain the enzymatic hydrolysate; (4) Deep solid-liquid separation: The enzymatic hydrolysate is centrifuged at 4000-6000 r / min and filtered through a 0.1-0.5 μm microfiltration membrane to obtain a clear carbon source mother liquor; (5) Compound preparation: Add 5%-10% compound supplement carbon source to the carbon source mother liquor, adjust the COD concentration to 120,000-180,000 mg / L, carbon-nitrogen ratio (20-25):1, carbon-phosphorus ratio (150-200):1, and obtain the prepared carbon source solution; (6) Stabilization treatment: Pump the prepared carbon source solution into the stabilization treatment tank, add 0.1%-0.3% compound stabilizer, adjust the pH to 6.0-7.0, and let it stand at room temperature for 12-24 hours; (7) Finished product testing and storage: The carbon source product after stabilization treatment is tested for COD, total nitrogen, total phosphorus, pH value and small molecule organic acid content. After all indicators are qualified, it is sealed and packaged and stored in a cool and dry environment.

2. The production process for preparing a composite carbon source using fruit and vegetable waste resources according to claim 1, characterized in that, In step (1), the particle size of the crushed material after washing and draining is 0.5-1.5cm, and it is pressed under a pressure of 0.8-1.2MPa.

3. The production process for preparing a composite carbon source using fruit and vegetable waste resources according to claim 1, characterized in that, In step (2), the anaerobic fermentation temperature of the compound fermentation agent is 35-38℃.

4. The production process for preparing a composite carbon source using fruit and vegetable waste resources according to claim 1, characterized in that, In step (2), the compound fermentation agent is Klebsiella acidogeneticus, Lactobacillus plantarum, and Bacillus subtilis.

5. The production process for using fruits and vegetables to produce a composite carbon source according to claim 4, characterized in that, The Klebsiella pneumoniae, Lactobacillus plantarum, and Bacillus subtilis are compounded in a mass ratio of 2:1:1, with an effective viable count ≥1×10^9 CFU / g.

6. The production process for preparing a composite carbon source using fruit and vegetable waste resources according to claim 1, characterized in that, In step (2), the acid-base regulator is food-grade citric acid or sodium hydroxide.

7. The production process for producing composite carbon sources using fruits and vegetables according to claim 1, characterized in that, In step (3), the compound enzyme preparation is cellulase, pectinase and amylase, and the cellulase, pectinase and amylase are compounded in an enzyme activity ratio of 3:2:

1.

8. The production process for producing composite carbon sources using fruits and vegetables according to claim 7, characterized in that, The cellulase activity is ≥50000 U / g, the pectinase activity is ≥30000 U / g, and the amylase activity is ≥40000 U / g.

9. The production process for producing composite carbon sources using fruits and vegetables according to claim 1, characterized in that, In step (5), the compound supplementary carbon source is food-grade sodium acetate, glucose and glycerol, which are mixed in a mass ratio of 2:3:1, and the purity of each raw material is ≥98%.

10. The production process for using fruits and vegetables to produce a composite carbon source according to claim 1, characterized in that, Step (6): The compound stabilizer is sodium citrate and sodium alginate, which are compounded in a mass ratio of 1:1.