A biological agent for improving waste fermentation environment of waste pool of waste incineration plant

Abstract

The application discloses a kind of biological inoculums for improving fermentation environment of waste pool of waste incineration plant, solve high kitchen garbage heavy metal pollution problem.It uses "functional strain + kitchen waste oil modified biochar carrier" collaborative design, functional strain includes Yarrowia lipolytica, Aspergillus oryzae, salt-tolerant lactic acid bacteria and Rhodotorula, Rhodotorula can efficiently passivate Pb 2+ , Cd 2+ , strain synergistic degradation of oil and starch.Application of percolate soluble heavy metal content reaches standard, reduces heavy metal treatment reagent dosage 25%-30%, reduces fly ash "hazardous waste" disposal ratio, realizes fermentation improvement and heavy metal passivation integration, with environmental protection and economic benefits.

Description

Technical Field

[0001] This invention relates to the field of biological treatment technology, specifically to a biological agent for improving the fermentation environment of waste pits in waste incineration plants. Background Technology

[0002] The main challenges in waste incineration plant waste pit treatment include the degradation of grease and starch, and heavy metal contamination. Existing microbial agents are primarily used for organic matter degradation and odor control, but they have failed to effectively address heavy metal contamination in waste pits, especially in cases with high levels of food waste. Heavy metals from worn tableware and food residues can be converted into soluble forms during fermentation, leading to leachate and fly ash contamination and increasing treatment costs. Current technologies for treating heavy metal-containing leachate and fly ash are costly and lack effective heavy metal control measures.

[0003] Therefore, there is an urgent need for an innovative technology that can both improve the fermentation efficiency of waste disposal sites and effectively control heavy metal pollution. This invention fills this technological gap by using a biological agent synergistically designed with "functional microbial communities + passivation carriers," providing a novel solution that can both degrade organic waste and passivate heavy metals. Summary of the Invention

[0004] To address the aforementioned problems, this invention proposes a biological agent for improving the fermentation environment of waste incineration plant waste pits. This agent combines a multifunctional microbial community with a modified carrier, possessing dual functions of oil and starch degradation and heavy metal passivation. It can significantly reduce the content of soluble heavy metals in waste pits, meeting relevant emission standards. This agent can be widely applied to waste pit pollution control, offering significant environmental and economic benefits.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A biological agent for improving the fermentation environment of waste pits in waste incineration plants, the agent comprising functional microbial communities and a composite carrier, and consisting of the following raw materials in parts by weight:

[0007] The functional microbial community consists of 2-4 parts of *Yarrowia lipolytica*, 1.5-3 parts of *Aspergillus oryzae*, 0.5-1 part of salt-tolerant lactic acid bacteria, and 1-2 parts of *Saccharomyces ruthenicum*. *Saccharomyces ruthenicum* can secrete polysaccharide and protein-like extracellular polymers to complex and fix Pb. 2+ Cd 2+ Heavy metal ions, passivation rate 90%-92%;

[0008] The composite carrier is composed of 5-8 parts of modified biochar, 60-75 parts of corn cob powder and 15-25 parts of bentonite; the modified biochar is produced by activating agricultural or forestry waste with kitchen waste oil and has a porous structure.

[0009] The functional microbial community is loaded onto a composite carrier at a mass ratio of 1:8 to 1:12, forming a synergistic system that combines waste fermentation improvement with heavy metal passivation. The viable bacterial concentration of the loaded microbial agent is 5 × 10⁻⁶. 7 -5×10 8 CFU / g.

[0010] Optionally, the *Saccharomyces rouxii* strain is kept at 10 mg / L Pb. 2+ In the simulated system, the passivation rate was 90%-92% after 72 hours, at 5 mg / L Cd. 2+ The passivation rate in the simulated system was 85%-88% after 72 hours.

[0011] Optionally, the agricultural or forestry waste may be one or more of corn cobs, sawdust, and straw.

[0012] Optionally, the modified biochar has a 35%-45% higher adsorption capacity for Cr and As than the unmodified biochar.

[0013] Optionally, the biological agent reduces the soluble heavy metal content during the fermentation of kitchen waste to 0.05-0.1 mg / L, meeting the leachate discharge standard of GB 16889-2008.

[0014] Optionally, the preparation method of the biological agent for improving the fermentation environment of waste incineration plant waste pits includes the following specific preparation steps:

[0015] S1. Mix kitchen waste oil with agricultural or forestry waste at a mass ratio of 1:5-1:8. Stir the mixture for 15-30 minutes using a high-speed mixer at 300-500 rpm. Then, place the mixture in a tube furnace or reactor and pyrolyze it at 400-500℃ under a nitrogen atmosphere for 2-3 hours. After pyrolysis, allow it to cool naturally to room temperature. Then, pulverize the mixture with mechanical equipment to a particle size of 150-200 mesh, sieve it to 80-100 mesh, and dry it to a moisture content of 3% to 5% to obtain the modified biochar.

[0016] S2. Inoculate *Yersinia lipolyticis*, *Aspergillus oryzae*, salt-tolerant lactic acid bacteria, and *Saccharomyces ruthenicum* into their respective dedicated culture media for activation and expansion culture. Mix the four bacterial solutions at a viable cell ratio of 3:2:1:1.2-2 and stir with a sterile mixer at 100-150 rpm for 10-15 minutes to obtain a uniformly dispersed composite bacterial solution.

[0017] S3. Weigh the modified biochar, corn cob powder and bentonite, place the three in a twin-screw mixer, mix for 15-20 minutes at 30-40℃ and 150-200 rpm, and dry the mixture to a moisture content of 5%-8% to obtain the composite carrier.

[0018] S4. Spray the compound bacterial culture solution evenly into the compound carrier while spraying. Stir and adsorb the solution at 25-30℃ and 60%-70% humidity. The stirring speed is 80-100 rpm and the adsorption time is 4-6 hours. During this period, the pH value of the system is checked every 1 hour to maintain the pH at 5.5-6.5.

[0019] S5. Place the loaded mixture in a vacuum drying oven and dry it at 40-45℃ and a vacuum of -0.08 to -0.06 MPa until the moisture content is 3%-5%. Then, pulverize it to 80-100 mesh using an ultrafine pulverizer, sieve it, and test the total viable count to ensure a viable count of 5×10⁻⁶. 7 -5×10 8 CFU / g, that is, the biological agent used to improve the fermentation environment of the waste incineration plant's waste pond.

[0020] The beneficial effects of this invention are:

[0021] The biological agent prepared by this invention has excellent dual functions: it can effectively degrade grease and starch in landfills, and significantly passivate Pb in landfills. 2+ Cd 2+ This microbial agent contains heavy metal ions and boasts a passivation rate of 90%-92%. It can reduce the soluble heavy metal content in landfills to 0.05 mg / L to 0.1 mg / L, meeting the GB 16889-2008 leachate discharge standard and significantly reducing leachate treatment costs. Simultaneously, the porous structure of the modified biochar provides excellent attachment sites for the microbial community, enhancing the agent's survival rate and degradation effect. This biological agent not only improves the fermentation efficiency of landfills but also provides a highly efficient heavy metal pollution control solution for waste incineration plants, demonstrating significant environmental and economic benefits. Attached Figure Description

[0022] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used together with the embodiments of the invention to explain the invention and do not constitute a limitation thereof.

[0023] Figure 1 Different Pb samples of this invention 2+ and Cd 2+ Passivation rate histogram;

[0024] Figure 2 This is a line graph showing the change in oil degradation rate over time for different samples of this invention at 30°C.

[0025] Figure 3 This is a line graph showing the change in the survival rate of bacterial communities in different samples over time according to the present invention. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0027] Example 1:

[0028] This embodiment 1 describes a biological agent for improving the fermentation environment of waste incineration plant waste pits. The biological agent is prepared from the following raw materials in parts by weight:

[0029] Functional microbiota: 3 parts of Yeastra lipolytica, 2 parts of Aspergillus oryzae, 0.5 parts of salt-tolerant lactic acid bacteria, and 1.5 parts of Saccharomyces roximately 1.5 parts;

[0030] Composite carrier: 6 parts modified biochar, 74 parts corn cob powder and 20 parts bentonite;

[0031] The preparation method of the composite carrier is as follows:

[0032] S1. Mix kitchen waste oil and straw powder (particle size 20-40 mesh) at a mass ratio of 1:6, and stir with a high-speed mixer at 400 rpm for 20 minutes.

[0033] S2. The mixture is placed in a tube furnace and pyrolyzed at 450°C under a nitrogen atmosphere for 2.5 h to complete the biochar modification process.

[0034] S3. After pyrolysis, the product is naturally cooled to room temperature, and then mechanically crushed into particles of 150 to 200 mesh.

[0035] S4. The pulverized modified biochar is sieved and dried, sieved to 80 to 100 mesh, and dried to a moisture content of 3% to 5%.

[0036] S5. Weigh corn cob powder, bentonite and modified biochar, mix them at 35℃ and 180rpm for 18min, and dry them to a moisture content of 5%-8% to obtain the composite carrier.

[0037] The preparation method of the biological agent is as follows:

[0038] S1. *Yersinia lipolytica*, *Aspergillus oryzae*, salt-tolerant lactic acid bacteria, and *Saccharomyces rouxii* were cultured separately. *Yersinia lipolytica* was cultured in a liquid medium containing glucose and a nitrogen source at 30°C and pH 5.5-6.0 for 48 h until the cell concentration reached 1×10⁻⁶. 8CFU / mL; Aspergillus oryzae was cultured for 48 h in a solid medium containing starch and nitrogen source at 30°C and pH 5.0-5.5 to achieve a cell concentration of 1×10⁻⁶. 8 CFU / mL; Salt-tolerant lactic acid bacteria were cultured for 24 h in a liquid medium containing lactose and a nitrogen source at 30°C and pH 6.0-6.5 until the bacterial concentration reached 1×10⁻⁶. 8 CFU / mL; *Saccharomyces rouxii* was cultured in a liquid medium containing glucose and nitrogen source at 30°C and pH 5.5-6.0 for 48 h to achieve a cell concentration of 1×10⁻⁶. 8 CFU / mL;

[0039] S2. Mix the above four strains in a volume ratio of 3:2:1:1.5, and prepare a total bacterial culture volume of 100 mL, with each strain having a concentration of 10. 8 CFU / mL, using a sterile mixer at 120 rpm for 13 min, to obtain a uniformly dispersed complex bacterial culture solution;

[0040] S3. Spray the composite bacterial solution evenly onto the composite carrier at a mass ratio of 1:8. While spraying, stir and adsorb the solution in an environment of 28℃ and 65% humidity. The stirring speed is 90 rpm and the adsorption time is 5 hours. During this period, the pH value of the system is measured every 1 hour to maintain the pH at 5.5-6.5.

[0041] S4. Place the loaded mixture in a vacuum drying oven and dry it at 43℃ and a vacuum of -0.07MPa until the moisture content is 3%-5%. Then, pulverize it to 80-100 mesh using an ultrafine pulverizer, sieve it, and test the total viable count to ensure that the total viable count reaches 10. 9 -10 10 CFU / g, that is, the biological agent used to improve the fermentation environment of the waste incineration plant's waste pond.

[0042] Example 2:

[0043] This embodiment 2 presents a biological agent for improving the fermentation environment of waste incineration plant waste pits. The biological agent is prepared from the following raw materials in parts by weight:

[0044] Functional microbiota: 3 parts of Yeastra lipolytica, 2 parts of Aspergillus oryzae, 0.5 parts of salt-tolerant lactic acid bacteria, and 2 parts of Saccharomyces roximately var. leucosus;

[0045] Composite carrier: 6 parts modified biochar, 74 parts corn cob powder and 20 parts bentonite;

[0046] The preparation method of the composite carrier is the same as that in Example 1;

[0047] The preparation method of the biological agent for improving the fermentation environment of the waste incineration plant waste pit in Example 2 is the same as that in Example 1, except that the amount of Saccharomyces roximately 2 parts is increased.

[0048] Example 3:

[0049] This embodiment 3 describes a biological agent for improving the fermentation environment of waste incineration plant waste pits. The biological agent is prepared from the following raw materials in parts by weight:

[0050] Functional microbiota: 3 parts of Yeastra lipolytica, 2 parts of Aspergillus oryzae, 0.5 parts of salt-tolerant lactic acid bacteria, and 1.5 parts of Saccharomyces roximately 1.5 parts;

[0051] Composite carrier: 6 parts modified biochar, 70 parts corn cob powder and 24 parts bentonite;

[0052] The preparation method of the composite carrier is the same as that in Example 1, except that the proportion of carrier raw materials is adjusted.

[0053] In this embodiment, the preparation method of a biological agent for improving the fermentation environment of waste incineration plant waste pits is the same as that in embodiment 1.

[0054] Comparative Example 1:

[0055] The biological agent of Comparative Example 1 was prepared from the following raw materials in parts by weight:

[0056] Functional microbiota: 3 parts of Yeastra lipolytica, 2 parts of Aspergillus oryzae, and 0.5 parts of salt-tolerant lactic acid bacteria;

[0057] Composite carrier: 6 parts modified biochar, 74 parts corn cob powder and 20 parts bentonite;

[0058] The preparation method of the modified biochar in Comparative Example 1 was the same as that in Example 1;

[0059] The preparation method of the biological agent in Comparative Example 1 is the same as that in Example 1, except that Saccharomyces rouxii is not added.

[0060] Comparative Example 2:

[0061] The biological agent of Comparative Example 2 was prepared from the following raw materials in parts by weight:

[0062] Functional microbiota: 3 parts of Yeastra lipolytica, 2 parts of Aspergillus oryzae, 0.5 parts of salt-tolerant lactic acid bacteria, and 1.5 parts of Saccharomyces roximately 1.5 parts;

[0063] Composite carrier: 6 parts ordinary biochar, 74 parts corn cob powder and 20 parts bentonite;

[0064] The preparation method of the composite carrier is the same as that in Example 1, except that no kitchen waste oil is added for modification. Straw powder (particle size 20-40 mesh) is placed directly in a tube furnace and pyrolyzed and activated at 450°C under a nitrogen atmosphere for 2.5 h to obtain ordinary biochar.

[0065] The preparation method of the biological agent in Comparative Example 2 is the same as that in Example 1.

[0066] Performance testing

[0067] 1. Heavy metal passivation rate test

[0068] Prepare Pb containing 10 mg / L 2+ and 5 mg / L Cd 2+ A simulated system solution was prepared, and a certain amount of biological agent was uniformly added to it at a ratio of 1:8. The mixed solution was then placed in a constant-temperature shaker and incubated at 30°C and 120 rpm for 72 h. After 72 h, samples were taken and Pb was determined using inductively coupled plasma optical emission spectrometry (ICP-OES) or atomic absorption spectrometry (AAS). 2+ and Cd 2+ The concentration changes were assessed. The test results were evaluated to ensure compliance with GB 16889-2008 leachate discharge standards, guaranteeing that heavy metal concentrations were below the maximum discharge limits. The passivation rate of heavy metals was calculated based on the difference between the initial and treated concentrations.

[0069]

[0070] Table 1. Test data on heavy metal passivation rate of each sample

[0071]

[0072] The biological agent of the present invention exhibits excellent performance in heavy metal passivation, as shown in Example 1 with Pb. 2+ and Cd 2+ The passivation rates were 92% and 88%, respectively, far exceeding the 20% and 10% of commercially available waste fermentation inoculants. In contrast, removing *Saccharomyces ruvidii* or using ordinary biochar significantly reduced the passivation effect, verifying the key roles of modified biochar and *Saccharomyces ruvidii* in passivation.

[0073] 2. Test on the degradation effect of oil / starch

[0074] In the oil / starch degradation effect test, waste containing oil and starch was mixed with a biological agent at a mass ratio of 1:8 and placed in a simulated landfill environment. The temperature was adjusted to 30℃, the pH was controlled at 5.5-6.5, and the stirring rate was maintained at 120 rpm. After 0 h, 12 h, 24 h, 48 h, and 72 h, samples were taken and the degradation of oil and starch was analyzed by gas chromatography-mass spectrometry (GC-MS) or high performance liquid chromatography (HPLC). The degradation effect of the biological agent was evaluated by calculating the degradation rate.

[0075] Table 2. Test data on the degradation effect of oil / starch on each sample.

[0076]

[0077] The biological agent of this invention achieves a 93% degradation rate of oils and a 88% degradation rate of starch after 72 hours, far exceeding the degradation effects of commercially available waste fermentation agents. Commercially available agents exhibit poor degradation performance, with oil and starch degradation rates of only 50% and 40%, respectively, demonstrating the high efficiency and technological advantages of the agent of this invention in the waste fermentation environment.

[0078] 3. Stability and activity test of bacterial community

[0079] The biological agent was inoculated into a simulated landfill environment, with the temperature set at 30°C, pH 5.5-6.5, and salinity 1-3%. The bacteria were cultured in the simulated environment, and samples were taken periodically (after 0 h, 12 h, 24 h, 48 h, and 72 h) to determine the survival rate and activity of the bacterial community. The CFU (cell molecule count) method was used to measure the bacterial concentration, and the morphology of the bacterial community was observed under a microscope. The adhesion of the bacterial community to the carrier surface was measured every 12 h to ensure stable attachment of the bacterial community to the composite carrier. These tests evaluated the stability and activity of the bacterial community under high-salt and high-temperature environmental conditions.

[0080] Table 3. Test data on bacterial survival rate, bacterial concentration, and adhesion rate for each sample.

[0081]

[0082] The biological agent of this invention exhibits excellent survival rate and adhesion in a simulated landfill environment. After 72 hours, the survival rate remains at 75%-85%, and the adhesion rate remains at 65%-75%, demonstrating its long-term stability and activity. In contrast, the survival rate of commercially available landfill fermentation agents is only 20%, and the adhesion rate is only 15%, far lower than that of the agent of this invention, proving the technical advantages of this invention.

[0083] 4. Fermentation temperature adaptability test

[0084] Different temperature conditions (30℃, 40℃, 50℃) were set, while maintaining a constant pH of 6.5 and salinity of 1%. The bio-inoculant was inoculated into a simulated landfill environment at a mass ratio of 1:8 and cultured at different temperatures. Samples were taken every 12, 24, 48, and 72 hours to measure bacterial survival rate and concentration. The degradation rate of oils and starches was tested by GC-MS or HPLC, and the passivation rate of heavy metals was tested by ICP-OES or AAS. These data were used to evaluate the activity, degradation effect, and heavy metal passivation ability of the microbial community at different temperatures, and to determine the optimal temperature conditions.

[0085] Table 4. Oil degradation rate and Pb of each sample at 40℃ 2+ Passivation rate test results table

[0086]

[0087] Table 5. Oil degradation rate and Pb of each sample at 50℃ 2+ Passivation rate test results table

[0088]

[0089] By comparing the test data under conditions of 30°C, 40°C, and 50°C, we can see that the biological agent of the present invention exhibits strong adaptability to high-temperature environments, especially under 30°C conditions, where its oil degradation rate and Pb content are significantly higher. 2+ The passivation rates were significantly higher than other samples, and good degradation and passivation effects were maintained even at 50°C. In contrast, commercially available waste fermentation inoculants showed lower oil degradation rates and lower Pb levels under high-temperature conditions. 2+ The passivation rate is significantly low, making it ineffective in dealing with grease degradation and heavy metal passivation in the landfill environment.

[0090] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A biological agent for improving the fermentation environment of waste pits in waste incineration plants, said agent comprising functional microbial communities and a composite carrier, characterized in that, It consists of the following raw materials in parts by weight: The functional microbial community consists of 2-4 parts of *Yarrowia lipolytica*, 1.5-3 parts of *Aspergillus oryzae*, 0.5-1 part of salt-tolerant lactic acid bacteria, and 1-2 parts of *Saccharomyces ruthenicum*. *Saccharomyces ruthenicum* can secrete polysaccharide and protein-like extracellular polymers to complex and fix Pb. 2+ Cd 2+ Heavy metal ions, passivation rate 90%-92%; The composite carrier is composed of 5-8 parts of modified biochar, 60-75 parts of corn cob powder and 15-25 parts of bentonite; the modified biochar is produced by activating agricultural or forestry waste with kitchen waste oil and has a porous structure. The functional microbial community is loaded onto a composite carrier at a mass ratio of 1:8 to 1:12, forming a synergistic system that combines waste fermentation improvement with heavy metal passivation. The viable bacterial concentration of the loaded microbial agent is 5 × 10⁻⁶. 7 -5×10 8 CFU / g.

2. The biological agent for improving the fermentation environment of waste incineration plant waste pits according to claim 1, characterized in that, The *Rhus oryzae* strain was subjected to 10 mg / L Pb. 2+ In the simulated system, the passivation rate was 90%-92% after 72 hours, at 5 mg / L Cd. 2+ The passivation rate in the simulated system was 85%-88% after 72 hours.

3. The biological agent for improving the fermentation environment of waste incineration plant waste pits according to claim 1, characterized in that, The agricultural or forestry waste is one or more of corn cobs, sawdust, and straw.

4. The biological agent for improving the fermentation environment of waste incineration plant waste pits according to claim 1, characterized in that, The modified biochar has a 35%-45% higher adsorption capacity for Cr and As compared to the unmodified biochar.

5. A biological agent for improving the fermentation environment of waste incineration plant waste pits according to claim 1, characterized in that, The biological agent reduces the soluble heavy metal content during the fermentation of kitchen waste to 0.05-0.1 mg / L, meeting the leachate discharge standard of GB 16889-2008.

6. A method for preparing a biological agent for improving the fermentation environment of a waste incineration plant's waste pit, according to any one of claims 1-5, characterized in that, The specific preparation steps are as follows: S1. Mix kitchen waste oil with agricultural or forestry waste at a mass ratio of 1:5-1:

8. Stir the mixture for 15-30 minutes using a high-speed mixer at 300-500 rpm. Then, place the mixture in a tube furnace or reactor and pyrolyze it at 400-500℃ under a nitrogen atmosphere for 2-3 hours. After pyrolysis, allow it to cool naturally to room temperature. Then, pulverize the mixture with mechanical equipment to a particle size of 150-200 mesh, sieve it to 80-100 mesh, and dry it to a moisture content of 3% to 5% to obtain the modified biochar. S2. Inoculate *Yersinia lipolyticis*, *Aspergillus oryzae*, salt-tolerant lactic acid bacteria, and *Saccharomyces ruthenicum* into their respective dedicated culture media for activation and expansion culture. Mix the four bacterial solutions at a viable cell ratio of 3:2:1:1.2-2 and stir with a sterile mixer at 100-150 rpm for 10-15 minutes to obtain a uniformly dispersed composite bacterial solution. S3. Weigh the modified biochar, corn cob powder and bentonite, place the three in a twin-screw mixer, mix for 15-20 minutes at 30-40℃ and 150-200 rpm, and dry the mixture to a moisture content of 5%-8% to obtain the composite carrier. S4. Spray the compound bacterial culture solution evenly into the compound carrier while spraying. Stir and adsorb the solution at 25-30℃ and 60%-70% humidity. The stirring speed is 80-100 rpm and the adsorption time is 4-6 hours. During this period, the pH value of the system is checked every 1 hour to maintain the pH at 5.5-6.

5. S5. Place the loaded mixture in a vacuum drying oven and dry it at 40-45℃ and a vacuum of -0.08 to -0.06 MPa until the moisture content is 3%-5%. Then, pulverize it to 80-100 mesh using an ultrafine pulverizer, sieve it, and test the total viable count to ensure that the viable count reaches 5×10⁻⁶. 7 -5×10 8 CFU / g, which is the biological agent used to improve the fermentation environment of the waste incineration plant's waste pond.

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