Method for sludge aerobic composting based on carbon-loaded functional microbial inoculum

Abstract

The invention relates to the technical field of urban residual sludge treatment, and particularly discloses a sludge aerobic composting method based on a carbon-loaded functional fungicide, which comprises the following steps: A1, mixing sludge powder and straw powder, fully soaking the mixture with a pore-forming agent solution, drying, and heating and calcining at high temperature to obtain biomass charcoal; a2, livestock manure, biomass charcoal and straw powder are mixed, aspergillus niger liquid is added into the mixture for fermentation, then compound bacteria liquid is added, fermentation continues, after fermentation is finished, strain protection liquid is added, drying is conducted, and a charcoal-loaded functional bacterial agent is obtained; and A3, uniformly mixing the sludge, the straw powder and the carbon-loaded functional fungicide, and carrying out aerobic composting on the sludge. According to the method, the aerobic composting temperature of the sludge can be increased, the composting time can be shortened, the form of heavy metals in the compost can be changed, the bioavailability of the heavy metals can be reduced, and harmless, reduction and resource utilization of the residual sludge can be realized.

Description

Technical Field

[0001] The present application relates to the technical field of urban surplus sludge treatment, and more specifically, to a method for aerobic composting of sludge based on carbon-supported functional bacterial agents. Background Art

[0002] Excess sludge is a solid-liquid mixed flocculent substance produced during the sewage treatment process. It is mainly composed of various organic matter, microorganisms, solid particles, colloids and other substances. It has the characteristics of high water content, complex composition and huge output. Excess sludge has both waste and resource characteristics. The sludge contains a large amount of difficult-to-degrade organic matter, heavy metals, salts and volatile substances, as well as pathogens and parasite eggs, which pose a threat to the biological safety of the environment. Although traditional sludge disposal methods, such as landfill and incineration, reduce the content of sludge, they are also accompanied by the emergence of new environmental problems.

[0003] Aerobic composting technology for sludge is the mainstream method for harmless disposal of sludge at home and abroad at this stage. Under artificial control conditions, bacterial microorganisms are used to decompose and utilize organic matter in the sludge, causing the temperature of the pile to rise. The use of high-temperature piles can not only accelerate the decomposition of organic raw materials, promote the passivation of heavy metals, and reduce the organic matter content in the sludge, but also change the form of heavy metals in the pile, reduce the bioavailability of heavy metals, promote the passivation of heavy metals, etc., to achieve the stabilization and harmlessness of raw materials. Therefore, a method of aerobic composting of sludge is urgently needed, which can not only increase the temperature of the pile but also prolong the duration of high temperature, which is of very important practical significance for the cleaning and secondary utilization of sludge. Summary of the invention

[0004] In order to solve the technical problems mentioned in the background technology, the present application provides a method for aerobic composting of sludge based on carbon-supported functional bacterial agents.

[0005] A method for aerobic composting of sludge based on carbon-supported functional bacterial agents comprises the following steps: A1. Dry the sludge and straw separately, crush and sieve them, mix the sludge powder and straw powder, and then soak the mixture in a pore-forming agent solution for 12-24 hours at a soaking temperature of 50-70°C, dry it, heat it in a muffle furnace at high temperature and calcine it, and cool it naturally to obtain biochar; A2. Mix livestock manure, biochar and straw powder, adjust the carbon-nitrogen ratio of the mixture to 20-30:1, and the water content to 45-50%. Add Aspergillus niger solution to the mixture for fermentation at a temperature of 25-40°C for 1-2 days, add the composite bacterial solution, raise the temperature to 50-70°C, and continue to ferment for 12-14 days. After the fermentation is completed, add the bacterial protection solution, mix well, and dry at 60-80°C for 18-24 hours under nitrogen protection to obtain a carbon-supported functional bacterial agent. A3. Evenly mix the sludge, straw powder and charcoal-loaded functional bacterial agent, adjust the moisture content to 58-65%, the carbon-nitrogen ratio to 25-32:1, and perform aerobic composting of the sludge.

[0006] Preferably, in step A1, the mass ratio of sludge powder, straw powder and pore-forming agent solution is 5-8:20-22:40-55.

[0007] Preferably, the pore-forming agent solution in step A1 is composed of phosphoric acid, polyvinyl alcohol and deionized water in a mass ratio of 4-6:0.5-1:10-12.

[0008] Preferably, the high temperature heating calcination conditions in step A1 are: first heating to 180-230° C., maintaining for 0.5-1 h, then heating to 600-800° C. at a heating rate of 10-12° C., and continuing calcination for 1-2 h.

[0009] Preferably, in step A2, the mass ratio of the mixture, the Aspergillus niger solution, the composite bacterial solution and the bacterial strain protection solution is 100: 0.1-0.5: 0.5-1: 60-80.

[0010] Preferably, the concentration of the Aspergillus niger solution in step A2 is 1×10 7 -1×10 9 CFU / mL.

[0011] Preferably, in step A2, the volume ratio of the thermophilic Bacillus liquid to the thermophilic actinomycetes liquid is 5-8:0.5-1.

[0012] Preferably, the concentration of the thermophilic Bacillus bacterial solution in step A2 is 2×10 8 -1×10 9 CFU / mL.

[0013] Preferably, the concentration of the thermophilic actinomycete solution in step A2 is 3×10 7 -1×10 8 CFU / mL.

[0014] Preferably, the strain protection solution in step A2 is composed of a plant extract, glycerol and a fucoidan aqueous solution in a mass ratio of 1-2:10-12:100.

[0015] Preferably, the plant extract is one or more of cinnamon extract, lemongrass extract, peppermint extract and snow chrysanthemum extract.

[0016] Preferably, the mass concentration of the fucoidan aqueous solution is 4-8%.

[0017] Preferably, the conditions for aerobic composting of sludge in step A3 are as follows: the forced ventilation flow rate is 30-40 m³ / h, the ventilation mode is intermittent ventilation, the ventilation time is 2-5 min, the stop time is 20-30 min, and the compost is turned 1-2 times a day.

[0018] In summary, this application has the following beneficial effects: The pore-forming agent prepared by compounding phosphoric acid and polyvinyl alcohol in this application can avoid the single pores formed by phosphoric acid and the uneven pore size distribution. Polyvinyl alcohol forms micropores and mesopores through physical decomposition, and can construct a multi-scale pore structure inside the biochar, which not only increases the total porosity, but also optimizes the distribution of pores. This multi-scale pore structure can significantly increase the specific surface area of ​​the biochar and enhance its adsorption capacity. In addition, before polyvinyl alcohol decomposes at high temperature, it can form a cross-linked structure inside the biomass to enhance the mechanical strength of the raw material. The phosphate compounds formed by the combination of phosphoric acid and minerals further enhance the mechanical strength of the biochar. This dual reinforcement effect enables the biochar to maintain a good shape and structure after high-temperature calcination.

[0019] In the preparation process of carbon-supported functional bacterial agent, the present application first adds Aspergillus niger to accelerate the initial decomposition of substrate at a lower temperature in the early stage of fermentation, and provides a more easily available nutrient source for subsequent microbial activities, and then adds thermophilic Bacillus and thermophilic actinomycetes. Aspergillus niger is the main decomposer in the early stage of fermentation, and the growth and metabolic process of Aspergillus niger can change the physical structure of the mixture, such as increasing the porosity of the material by forming a mycelium network. This not only helps to improve the air permeability of the mixture, but also provides a better habitat for thermophilic Bacillus and thermophilic actinomycetes, promotes the exchange of oxygen and other gases, and is conducive to their growth and metabolic activities. Mutual competition and inhibition can be avoided by adding in stages, so that each microorganism has enough time to adapt to the environment and play its best role. In addition, Aspergillus niger can degrade extracellular polysaccharides and complex organic matter in sludge, reduce the viscosity and water retention capacity of sludge, thereby reducing the water content of sludge, which helps to accelerate the mineralization of organic matter in sludge and improve the treatment efficiency of organic waste. The metabolites of thermophilic Bacillus and thermophilic actinomycetes can promote sludge granulation, and work together with Aspergillus niger to improve the structure of sludge, making it easier to dehydrate, and fix heavy metals in sludge through bioadsorption or biomineralization between bacterial species, reducing their mobility and bioavailability, thereby reducing their harm to the environment.

[0020] In the preparation process of the charcoal-borne functional bacterial agent, the present application uses a strain protection solution prepared from plant extracts, glycerol and a fucoidan aqueous solution, and fixes the strain therein through multiple protection mechanisms such as inhibiting the growth of harmful microorganisms, stabilizing the cell membrane structure of the strain and the gel-like substance formed by cross-linking of fucoidan and calcium ions, forming a stable microcapsule structure to protect the strain from the adverse effects of the external environment. This can significantly improve the stress resistance of the strain, increase the temperature tolerance of the charcoal-borne functional bacterial agent, improve its survival rate and biological activity, protect the strain from the influence of adverse environmental factors during storage, transportation and subsequent aerobic composting, increase the temperature of the aerobic composting pile, and improve the composting efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 The temperature changes during aerobic composting of sludge; Figure 2 The changes of organic matter content during aerobic composting of sewage sludge; Figure 3 The Cu form changes before and after aerobic composting of sludge. DETAILED DESCRIPTION

[0022] The present application is further described in detail below with reference to the embodiments.

[0023] The polyvinyl alcohol (model: L) used in the examples and comparative examples of the present application was purchased from Anhui Longyang Environmental Protection Technology Co., Ltd.; thermophilic Bacillus (product name: Bacillus thermophilum, product number: BMZ134386); thermophilic actinomycetes (product name: Thermoactinospora rubra, product number: BMZ134155) and Aspergillus niger (product name: Aspergillus niger, product number: BMZ135481) were all purchased from Ningbo Mingzhou Biotechnology Co., Ltd.; fucoidan was purchased from Shandong Fengtai Biotechnology Co., Ltd.; cinnamon extract was purchased from Hebei Jiuyu Biotechnology Co., Ltd.

[0024] Examples 1-3 and Comparative Examples 1-6 provide a method for aerobic composting of sludge based on carbon-supported functional bacterial agents.

[0025] Example 1 A method for aerobic composting of sludge based on carbon-supported functional bacterial agents comprises the following steps: A1. Dry the sludge and straw separately, crush them through a 200-mesh sieve, mix the sludge powder and the straw powder, and then soak the mixture in a pore-forming agent solution for 12 hours at a soaking temperature of 50°C, dry it, and heat it in a muffle furnace for high-temperature calcination. First, heat it to 180°C and maintain it for 0.5h, then heat it to 600°C at a heating rate of 10°C, and continue calcining for 1h, and cool it naturally to obtain biochar, wherein the mass ratio of sludge powder, straw powder and pore-forming agent solution is 1:4:8, and the pore-forming agent solution is composed of phosphoric acid, polyvinyl alcohol and deionized water in a mass ratio of 4:0.5:10; A2. Mix cow dung, biochar and straw powder, adjust the carbon-nitrogen ratio of the mixture to 20:1, the water content to 45%, and add bacteria at a concentration of 1×10 7 CFU / mL of Aspergillus niger liquid was fermented at 25℃ for 1 day, and the composite bacterial liquid was added, and the temperature was raised to 50℃. The fermentation was continued for 12 days. After the fermentation, the strain protection liquid was added, mixed evenly, and dried at 60℃ for 18h under nitrogen protection to obtain a carbon-supported functional bacterial agent, wherein the mass ratio of the mixture, Aspergillus niger liquid, composite bacterial liquid and strain protection liquid was 100:0.1:0.5:60, and the bacterial concentration of the thermophilic Bacillus liquid in the composite bacterial liquid was 2×10 8 CFU / mL, the bacterial concentration of the thermophilic actinomycete solution is 3×10 7 CFU / mL, the volume ratio of thermophilic Bacillus liquid to thermophilic actinomycete liquid was 10:1, the strain protection liquid consisted of plant extract, glycerol and 4% fucoidan aqueous solution in a mass ratio of 1:10:100, and the plant extract was cinnamon extract; A3. Evenly mix the sludge, straw powder and charcoal-loaded functional bacterial agent, adjust the moisture content to 58%, the carbon-nitrogen ratio to 25:1, and carry out aerobic composting of the sludge. The conditions for aerobic composting of the sludge are as follows: the forced ventilation flow rate is 30m³ / h, the ventilation method is intermittent ventilation, the ventilation time is 2min, stop for 20min, and the pile is turned once a day.

[0026] Example 2 A method for aerobic composting of sludge based on carbon-supported functional bacterial agents comprises the following steps: A1. Dry the sludge and straw separately, crush them through a 250-mesh sieve, mix the sludge powder and the straw powder, and then soak the mixture in a pore-forming agent solution for 18 hours at a soaking temperature of 60°C, dry it, and heat it in a muffle furnace for high-temperature calcination. First, heat it to 200°C and maintain it for 0.8h, then heat it to 700°C at a heating rate of 11°C, and continue calcining for 1.5h. Cool it naturally to obtain biochar, wherein the mass ratio of sludge powder, straw powder and pore-forming agent solution is 6:21:48, and the pore-forming agent solution is composed of phosphoric acid, polyvinyl alcohol and deionized water in a mass ratio of 5:0.8:11; A2. Mix cow dung, biochar and straw powder, adjust the carbon-nitrogen ratio of the mixture to 25:1, the water content to 48%, and add bacteria at a concentration of 1×10 8 CFU / mL of Aspergillus niger liquid was fermented at 35℃ for 1.5 days, and the composite bacterial liquid was added. The temperature was raised to 60℃ and the fermentation was continued for 13 days. After the fermentation, the strain protection liquid was added, mixed evenly, and dried at 70℃ for 21 hours under nitrogen protection to obtain a carbon-supported functional bacterial agent. The mass ratio of the mixture, Aspergillus niger liquid, composite bacterial liquid and strain protection liquid was 100:0.3:0.8:70, and the bacterial concentration of the thermophilic Bacillus liquid in the composite bacterial liquid was 6×10 8 CFU / mL, the bacterial concentration of the thermophilic actinomycete solution is 7×10 7 CFU / mL, the volume ratio of thermophilic Bacillus liquid and thermophilic actinomycete liquid is 6:0.8, the strain protection liquid is composed of plant extract, glycerol and 6% fucoidan aqueous solution in a mass ratio of 1.5:11:100, and the plant extract is cinnamon extract; A3. Evenly mix the sludge, straw powder and charcoal-loaded functional bacterial agent, adjust the moisture content to 62%, the carbon-nitrogen ratio to 28:1, and carry out aerobic composting of the sludge. The conditions for aerobic composting of the sludge are as follows: the forced ventilation flow rate is 35m³ / h, the ventilation method is intermittent ventilation, the ventilation time is 4min, stop for 25min, and the compost is turned twice a day.

[0027] Example 3 A method for aerobic composting of sludge based on carbon-supported functional bacterial agents comprises the following steps: A1. Dry the sludge and straw separately, crush them through a 300-mesh sieve, mix the sludge powder and the straw powder, and then soak the mixture in a pore-forming agent solution for 24 hours at a soaking temperature of 70°C, dry it, and heat it in a muffle furnace for high-temperature calcination. First, heat it to 230°C and maintain it for 1 hour, then heat it to 800°C at a heating rate of 12°C, and continue calcining for 2 hours, and cool it naturally to obtain biochar, wherein the mass ratio of sludge powder, straw powder and pore-forming agent solution is 8:22:55, and the pore-forming agent solution is composed of phosphoric acid, polyvinyl alcohol and deionized water in a mass ratio of 6:1:12; A2. Mix cow dung, biochar and straw powder, adjust the carbon-nitrogen ratio of the mixture to 30:1, the water content to 50%, and add bacteria at a concentration of 1×10 9CFU / mL of Aspergillus niger liquid was fermented at 40℃ for 2 days, and then the composite bacterial liquid was added, and the temperature was raised to 70℃. The fermentation was continued for 14 days. After the fermentation, the strain protection liquid was added, mixed evenly, and dried at 80℃ for 24 hours under nitrogen protection to obtain a carbon-supported functional bacterial agent, wherein the mass ratio of the mixture, Aspergillus niger liquid, composite bacterial liquid and strain protection liquid was 100:0.5:1:80, and the bacterial concentration of the thermophilic Bacillus liquid in the composite bacterial liquid was 1×10 9 CFU / mL, the bacterial concentration of the thermophilic actinomycete solution is 1×10 8 CFU / mL, the volume ratio of thermophilic Bacillus liquid and thermophilic actinomycete liquid was 8:1, the strain protection liquid was composed of plant extract, glycerol and 8% fucoidan aqueous solution in a mass ratio of 1:6:50, and the plant extract was cinnamon extract; A3. Evenly mix the sludge, straw powder and charcoal-loaded functional bacterial agent, adjust the moisture content to 65%, the carbon-nitrogen ratio to 32:1, and carry out aerobic composting of the sludge. The conditions for aerobic composting of the sludge are as follows: the forced ventilation flow rate is 40m³ / h, the ventilation method is intermittent ventilation, the ventilation time is 5min, stop for 30min, and the pile is turned twice a day.

[0028] Comparative Example 1 A method for aerobic composting of sludge based on carbon-supported functional bacterial agents comprises the following steps: A1. Dry the sludge and straw separately, crush them through a 200-mesh sieve, mix the sludge powder and the straw powder, and then soak the mixture in a pore-forming agent solution for 12 hours at a soaking temperature of 50°C, dry it, and heat it in a muffle furnace for high-temperature calcination. First, heat it to 180°C and maintain it for 0.5h, then heat it to 600°C at a heating rate of 10°C, and continue calcining for 1h, and cool it naturally to obtain biochar, wherein the mass ratio of sludge powder, straw powder and pore-forming agent solution is 1:4:8, and the pore-forming agent solution is composed of phosphoric acid and deionized water in a mass ratio of 4.5:10; A2. Mix cow dung, biochar and straw powder, adjust the carbon-nitrogen ratio of the mixture to 20:1, the water content to 45%, and add bacteria at a concentration of 1×10 7 CFU / mL of Aspergillus niger liquid was fermented at 25℃ for 1 day, and the composite bacterial liquid was added, and the temperature was raised to 50℃. The fermentation was continued for 12 days. After the fermentation, the strain protection liquid was added, mixed evenly, and dried at 60℃ for 18h under nitrogen protection to obtain a carbon-supported functional bacterial agent, wherein the mass ratio of the mixture, Aspergillus niger liquid, composite bacterial liquid and strain protection liquid was 100:0.1:0.5:60, and the bacterial concentration of the thermophilic Bacillus liquid in the composite bacterial liquid was 2×10 8 CFU / mL, the bacterial concentration of the thermophilic actinomycete solution is 3×10 7CFU / mL, the volume ratio of thermophilic Bacillus liquid to thermophilic actinomycete liquid was 10:1, the strain protection liquid consisted of plant extract, glycerol and 4% fucoidan aqueous solution in a mass ratio of 1:10:100, and the plant extract was cinnamon extract; A3. Evenly mix the sludge, straw powder and charcoal-loaded functional bacterial agent, adjust the moisture content to 58%, the carbon-nitrogen ratio to 25:1, and carry out aerobic composting of the sludge. The conditions for aerobic composting of the sludge are as follows: the forced ventilation flow rate is 30m³ / h, the ventilation method is intermittent ventilation, the ventilation time is 2min, stop for 20min, and the pile is turned once a day.

[0029] Comparative Example 2 A method for aerobic composting of sludge based on carbon-supported functional bacterial agents comprises the following steps: A1. Dry the sludge and straw separately, crush them through a 200-mesh sieve, mix the sludge powder and the straw powder, and then soak the mixture in a pore-forming agent solution for 12 hours at a soaking temperature of 50°C, dry it, and heat it in a muffle furnace for high-temperature calcination. First, heat it to 180°C and maintain it for 0.5h, then heat it to 600°C at a heating rate of 10°C, and continue calcining for 1h, and cool it naturally to obtain biochar, wherein the mass ratio of sludge powder, straw powder and pore-forming agent solution is 1:4:8, and the pore-forming agent solution is composed of phosphoric acid, polyvinyl alcohol and deionized water in a mass ratio of 4:0.5:10; A2. Mix cow dung, biochar and straw powder, adjust the carbon-nitrogen ratio of the mixture to 20:1, the water content to 45%, and add bacteria at a concentration of 1×10 7 CFU / mL of Aspergillus niger liquid and composite bacterial liquid were fermented at 25℃ for 13 days. After the fermentation, bacterial strain protection liquid was added and mixed evenly. Under nitrogen protection, it was dried at 60℃ for 18h to obtain carbon-supported functional bacterial agent, wherein the mass ratio of the mixture, Aspergillus niger liquid, composite bacterial liquid and bacterial strain protection liquid was 100:0.1:0.5:60, and the bacterial concentration of thermophilic Bacillus liquid in the composite bacterial liquid was 2×10 8 CFU / mL, the bacterial concentration of the thermophilic actinomycete solution is 3×10 7 CFU / mL, the volume ratio of thermophilic Bacillus liquid to thermophilic actinomycete liquid was 10:1, the strain protection liquid consisted of plant extract, glycerol and 4% fucoidan aqueous solution in a mass ratio of 1:10:100, and the plant extract was cinnamon extract; A3. Evenly mix the sludge, straw powder and charcoal-loaded functional bacterial agent, adjust the moisture content to 58%, the carbon-nitrogen ratio to 25:1, and carry out aerobic composting of the sludge. The conditions for aerobic composting of the sludge are as follows: the forced ventilation flow rate is 30m³ / h, the ventilation method is intermittent ventilation, the ventilation time is 2min, stop for 20min, and the pile is turned once a day.

[0030] Comparative Example 3 A method for aerobic composting of sludge based on carbon-supported functional bacterial agents comprises the following steps: A1. Dry the sludge and straw separately, crush them through a 200-mesh sieve, mix the sludge powder and the straw powder, and then soak the mixture in a pore-forming agent solution for 12 hours at a soaking temperature of 50°C, dry it, and heat it in a muffle furnace for high-temperature calcination. First, heat it to 180°C and maintain it for 0.5h, then heat it to 600°C at a heating rate of 10°C, and continue calcining for 1h, and cool it naturally to obtain biochar, wherein the mass ratio of sludge powder, straw powder and pore-forming agent solution is 1:4:8, and the pore-forming agent solution is composed of phosphoric acid, polyvinyl alcohol and deionized water in a mass ratio of 4:0.5:10; A2. Mix cow dung, biochar and straw powder, adjust the carbon-nitrogen ratio of the mixture to 20:1, the water content to 45%, and add bacteria at a concentration of 1×10 7 CFU / mL of Aspergillus niger liquid and composite bacterial liquid were fermented at a temperature of 50°C for 13 days. After the fermentation, bacterial strain protection liquid was added and mixed evenly. Under nitrogen protection, it was dried at 60°C for 18 hours to obtain a carbon-supported functional bacterial agent, wherein the mass ratio of the mixture, Aspergillus niger liquid, composite bacterial liquid and bacterial strain protection liquid was 100:0.1:0.5:60, and the bacterial concentration of the thermophilic Bacillus liquid in the composite bacterial liquid was 2×10 8 CFU / mL, the bacterial concentration of the thermophilic actinomycete solution is 3×10 7 CFU / mL, the volume ratio of thermophilic Bacillus liquid to thermophilic actinomycete liquid was 10:1, the strain protection liquid consisted of plant extract, glycerol and 4% fucoidan aqueous solution in a mass ratio of 1:10:100, and the plant extract was cinnamon extract; A3. Evenly mix the sludge, straw powder and charcoal-loaded functional bacterial agent, adjust the moisture content to 58%, the carbon-nitrogen ratio to 25:1, and carry out aerobic composting of the sludge. The conditions for aerobic composting of the sludge are as follows: the forced ventilation flow rate is 30m³ / h, the ventilation method is intermittent ventilation, the ventilation time is 2min, stop for 20min, and the pile is turned once a day.

[0031] Comparative Example 4 A method for aerobic composting of sludge based on carbon-supported functional bacterial agents comprises the following steps: A1. Dry the sludge and straw separately, crush them through a 200-mesh sieve, mix the sludge powder and the straw powder, and then soak the mixture in a pore-forming agent solution for 12 hours at a soaking temperature of 50°C, dry it, and heat it in a muffle furnace for high-temperature calcination. First, heat it to 180°C and maintain it for 0.5h, then heat it to 600°C at a heating rate of 10°C, and continue calcining for 1h, and cool it naturally to obtain biochar, wherein the mass ratio of sludge powder, straw powder and pore-forming agent solution is 1:4:8, and the pore-forming agent solution is composed of phosphoric acid, polyvinyl alcohol and deionized water in a mass ratio of 4:0.5:10; A2. Mix cow dung, biochar and straw powder, adjust the carbon-nitrogen ratio of the mixture to 20:1, the water content to 45%, add composite bacterial solution to the mixture, raise the temperature to 50℃, and continue fermentation for 12 days. Then add bacteria at a concentration of 1×10 7 CFU / mL of Aspergillus niger liquid was fermented at 25℃ for 1 day. After the fermentation, the strain protection liquid was added and mixed evenly. Under nitrogen protection, it was dried at 60℃ for 18h to obtain the carbon-supported functional bacterial agent. The mass ratio of the mixture, Aspergillus niger liquid, composite bacterial liquid and strain protection liquid was 100:0.1:0.5:60. The bacterial concentration of the thermophilic Bacillus liquid in the composite bacterial liquid was 2×10 8 CFU / mL, the bacterial concentration of the thermophilic actinomycete solution is 3×10 7 CFU / mL, the volume ratio of thermophilic Bacillus liquid to thermophilic actinomycete liquid was 10:1, the strain protection liquid consisted of plant extract, glycerol and 4% fucoidan aqueous solution in a mass ratio of 1:10:100, and the plant extract was cinnamon extract; A3. Evenly mix the sludge, straw powder and charcoal-loaded functional bacterial agent, adjust the moisture content to 58%, the carbon-nitrogen ratio to 25:1, and carry out aerobic composting of the sludge. The conditions for aerobic composting of the sludge are as follows: the forced ventilation flow rate is 30m³ / h, the ventilation method is intermittent ventilation, the ventilation time is 2min, stop for 20min, and the pile is turned once a day.

[0032] Comparative Example 5 A method for aerobic composting of sludge based on carbon-supported functional bacterial agents comprises the following steps: A1. Dry the sludge and straw separately, crush them through a 200-mesh sieve, mix the sludge powder and the straw powder, and then soak the mixture in a pore-forming agent solution for 12 hours at a soaking temperature of 50°C, dry it, and heat it in a muffle furnace for high-temperature calcination. First, heat it to 180°C and maintain it for 0.5h, then heat it to 600°C at a heating rate of 10°C, and continue calcining for 1h, and cool it naturally to obtain biochar, wherein the mass ratio of sludge powder, straw powder and pore-forming agent solution is 1:4:8, and the pore-forming agent solution is composed of phosphoric acid, polyvinyl alcohol and deionized water in a mass ratio of 4:0.5:10; A2. Mix cow dung, biochar and straw powder, adjust the carbon-nitrogen ratio of the mixture to 20:1, the water content to 45%, and add bacteria at a concentration of 1×10 7 CFU / mL of Aspergillus niger liquid was fermented at 25℃ for 1 day, and the composite bacterial liquid was added, and the temperature was raised to 50℃. The fermentation was continued for 12 days. After the fermentation, the strain protection liquid was added, mixed evenly, and dried at 60℃ for 18h under nitrogen protection to obtain a carbon-supported functional bacterial agent, wherein the mass ratio of the mixture, Aspergillus niger liquid, composite bacterial liquid and strain protection liquid was 100:0.1:0.5:60, and the bacterial concentration of the thermophilic Bacillus liquid in the composite bacterial liquid was 2×10 8 CFU / mL, the bacterial concentration of the thermophilic actinomycete solution is 3×10 7 CFU / mL, the volume ratio of thermophilic Bacillus liquid to thermophilic actinomycete liquid was 10:1, the strain protection liquid consisted of a plant extract with a mass ratio of 1:100 and a fucoidan aqueous solution with a mass concentration of 4%, and the plant extract was cinnamon extract; A3. Evenly mix the sludge, straw powder and charcoal-loaded functional bacterial agent, adjust the moisture content to 58%, the carbon-nitrogen ratio to 25:1, and carry out aerobic composting of the sludge. The conditions for aerobic composting of the sludge are as follows: the forced ventilation flow rate is 30m³ / h, the ventilation method is intermittent ventilation, the ventilation time is 2min, stop for 20min, and the pile is turned once a day.

[0033] Comparative Example 6 A method for aerobic composting of sludge based on carbon-supported functional bacterial agents comprises the following steps: A1. Dry the sludge and straw separately, crush them through a 200-mesh sieve, mix the sludge powder and the straw powder, and then soak the mixture in a pore-forming agent solution for 12 hours at a soaking temperature of 50°C, dry it, and heat it in a muffle furnace for high-temperature calcination. First, heat it to 180°C and maintain it for 0.5h, then heat it to 600°C at a heating rate of 10°C, and continue calcining for 1h, and cool it naturally to obtain biochar, wherein the mass ratio of sludge powder, straw powder and pore-forming agent solution is 1:4:8, and the pore-forming agent solution is composed of phosphoric acid, polyvinyl alcohol and deionized water in a mass ratio of 4:0.5:10; A2. Mix cow dung, biochar and straw powder, adjust the carbon-nitrogen ratio of the mixture to 20:1, the water content to 45%, and add bacteria at a concentration of 1×10 7CFU / mL of Aspergillus niger liquid was fermented at 25℃ for 1 day, and the composite bacterial liquid was added, and the temperature was raised to 50℃. The fermentation was continued for 12 days. After the fermentation, the strain protection liquid was added, mixed evenly, and dried at 60℃ for 18h under nitrogen protection to obtain a carbon-supported functional bacterial agent, wherein the mass ratio of the mixture, Aspergillus niger liquid, composite bacterial liquid and strain protection liquid was 100:0.1:0.5:60, and the bacterial concentration of the thermophilic Bacillus liquid in the composite bacterial liquid was 2×10 8 CFU / mL, the bacterial concentration of the thermophilic actinomycete solution is 3×10 7 CFU / mL, the volume ratio of thermophilic Bacillus liquid to thermophilic actinomycete liquid is 10:1, the strain protection liquid is composed of plant extract, glycerol and deionized water in a mass ratio of 1:10:100, and the plant extract is cinnamon extract; A3. Evenly mix the sludge, straw powder and charcoal-loaded functional bacterial agent, adjust the moisture content to 58%, the carbon-nitrogen ratio to 25:1, and carry out aerobic composting of the sludge. The conditions for aerobic composting of the sludge are as follows: the forced ventilation flow rate is 30m³ / h, the ventilation method is intermittent ventilation, the ventilation time is 2min, stop for 20min, and the pile is turned once a day.

[0034] Performance Testing The blank control group is the same as Example 1, except that the bacteria are not loaded on biochar, but directly added to the sludge for aerobic composting of the sludge. The temperature, organic matter content and Cu morphology before and after composting of the blank control group (CK) in the aerobic composting of the sludge and the addition of the charcoal-loaded functional bacterial agents prepared in Examples 1-3 (T1, T2, T3) of the present application and Comparative Examples 1-6 (T1-1, T1-2, T1-3, T1-4, T1-5, T1-6) are tested.

[0035] Determination of organic matter content: Place the porcelain crucible in a muffle at 600±20℃ and burn to constant weight; Weigh the sample (use tweezers to remove plastics, stones and other inactive substances in the sample, grind until all pass through a 0.25 mm aperture sieve, mix well, put into a ground-mouth bottle and store at room temperature for testing), spread it flat in a porcelain crucible, half cover the crucible lid, then place it in an electric drying oven, bake at 105±5℃ for 1h, take it out and move it into a desiccator to cool to room temperature, and weigh it; repeat the above steps for inspection drying, 30min each time, until constant weight; weigh the dried sample (recorded as M0), spread it flat in a porcelain crucible, cover the crucible, and then put it into a muffle furnace. After the temperature rises to 600℃, burn it at 600±20℃ for 3h, take it out and cool it in the air for 5min, then move it into a desiccator to cool to room temperature, and weigh it; repeat the above steps for inspection burning, 30min each time, until constant weight (recorded as M1); Organic matter content W = M0-M1 M0—Weigh the weight of the dried sample M1—Weigh the weight of the dried sample after burning Cu form test: refer to the BCR three-step extraction method for testing; The test results are attached. Figure 1-3 .

[0036] Depend on Figure 1 It can be seen that the compost (T1) added with the carbon-supported functional bacterial agent prepared in Example 1 reached the highest value at 72.2°C, and the compost (CK) of the blank control group reached the highest value at 55.1°C. Compared with the compost of CK, the highest temperature of the compost of T1 increased by 17.1°C, and the decomposition time was significantly shortened. Compared with the composts (T1-1, T1-2, T1-3, T1-4, T1-5, T1-6) added with the carbon-supported functional bacterial agent prepared in Comparative Examples 1-6, the compost temperature of T1 was significantly increased, effectively extending the duration of high temperature of the compost, significantly increasing the high temperature period, and effectively shortening the composting cycle.

[0037] Depend on Figure 2 It can be seen that the organic matter content of the pile (T1) to which the charcoal-supported functional bacterial agent prepared in Example 1 was added was significantly reduced compared with the piles to which the charcoal-supported functional bacterial agent prepared in Comparative Examples 1-6 were added after composting (T1-1, T1-2, T1-3, T1-4, T1-5, T1-6) and the pile of the blank control group (CK) after aerobic composting.

[0038] Depend on Figure 3 It can be seen that after the composting of the pile with the charcoal-supported functional bacterial agent prepared in Example 1 was completed (T1), compared with the composting of the pile with the charcoal-supported functional bacterial agent prepared in Comparative Examples 1-6 (T1-1, T1-2, T1-3, T1-4, T1-5, T1-6) and the pile of the blank control group (CK) after aerobic composting, the oxidizable Cu and residual Cu were significantly increased, and the reducible and exchangeable Cu were significantly reduced.

[0039] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make modifications to the present embodiment without any creative contribution as needed, but such modifications are protected by the patent law as long as they are within the scope of the claims of the present application.

Claims

1. A method for aerobic composting of sludge based on carbon-supported functional bacterial agents, characterized in that: The following steps are involved: A1. Dry the sludge and straw separately, crush and sieve them, mix the sludge powder and straw powder, and then soak the mixture in a pore-forming agent solution for 12-24 hours at a soaking temperature of 50-70°C, dry it, heat it in a muffle furnace at high temperature and calcine it, and cool it naturally to obtain biochar; A2. Mix livestock manure, biochar and straw powder, adjust the carbon-nitrogen ratio of the mixture to 20-30:1, and the water content to 45-50%. Add Aspergillus niger solution to the mixture for fermentation at a temperature of 25-40°C for 1-2 days, add the composite bacterial solution, raise the temperature to 50-70°C, and continue to ferment for 12-14 days. After the fermentation is completed, add the bacterial protection solution, mix well, and dry at 60-80°C for 18-24 hours under nitrogen protection to obtain a carbon-supported functional bacterial agent. A3. Evenly mix the sludge, straw powder and charcoal-loaded functional bacterial agent, adjust the moisture content to 58-65%, the carbon-nitrogen ratio to 25-32:1, and perform aerobic composting of the sludge.

2. The method for aerobic composting of sludge based on carbon-supported functional bacterial agent according to claim 1, characterized in that: In the step A1, the mass ratio of the sludge powder, the straw powder and the pore-forming agent solution is 5-8:20-22:40-55.

3. The method for aerobic composting of sludge based on carbon-supported functional bacterial agent according to claim 1, characterized in that: The pore-forming agent solution in step A1 is composed of phosphoric acid, polyvinyl alcohol and deionized water in a mass ratio of 4-6:0.5-1:10-12.

4. The method for aerobic composting of sludge based on carbon-supported functional bacterial agent according to claim 1, characterized in that: The high temperature heating calcination conditions in step A1 are: firstly heating to 180-230°C, maintaining for 0.5-1h, then heating to 600-800°C at a heating rate of 10-12°C, and continuing calcination for 1-2h.

5. The method for aerobic composting of sludge based on carbon-supported functional bacterial agent according to claim 1, characterized in that: In the step A2, the mass ratio of the mixture, the Aspergillus niger liquid, the composite bacterial liquid and the bacterial strain protection liquid is 100: 0.1-0.5: 0.5-1: 60-80.

6. The method for aerobic composting of sludge based on carbon-supported functional bacterial agent according to claim 1, characterized in that: The concentration of the Aspergillus niger solution in step A2 is 1×10 7 -1×10 9 CFU / mL; the composite bacterial solution includes a thermophilic Bacillus bacterial solution and a thermophilic actinomycete bacterial solution; the volume ratio of the thermophilic Bacillus bacterial solution to the thermophilic actinomycete bacterial solution is 5-8:0.5-1; the bacterial concentration of the thermophilic Bacillus bacterial solution is 2×10 8 -1×10 9 CFU / mL; the bacterial concentration of the thermophilic actinomycete solution is 3×10 7 -1×10 8 CFU / mL.

7. The method for aerobic composting of sludge based on carbon-supported functional bacterial agent according to claim 1, characterized in that: The bacterial strain protection solution in step A2 is composed of a plant extract, glycerol and a fucoidan aqueous solution in a mass ratio of 1-2:10-12:

100.

8. The method for aerobic composting of sludge based on carbon-supported functional bacterial agent according to claim 7, characterized in that: The plant extract is one or more of cinnamon extract, lemongrass extract, mint extract and snow chrysanthemum extract; the mass concentration of the fucoidan aqueous solution is 4-8%.

9. The method for aerobic composting of sludge based on carbon-supported functional bacterial agent according to claim 1, characterized in that: The conditions for aerobic composting of sludge in step A3 are as follows: forced ventilation flow rate is 30-40 m³ / h, ventilation mode is intermittent ventilation, ventilation time is 2-5 min, stop time is 20-30 min, and compost is turned 1-2 times a day.

Images