Method for resource utilization of outdoor garden waste

Abstract

The application discloses an outdoor garden waste resource treatment method and belongs to the technical field of garden waste resource utilization. The carbon-nitrogen ratio, water content and pH of garden waste are adjusted by crushing the garden waste to a specific particle size, and then a compound microbial agent and a heating particle are added in sequence, and after being uniformly mixed, film covering fermentation is carried out, so that the prepared heating particle can slowly, continuously and stably release heat to improve the temperature of the heap, and the problem that the long time of composting and the incomplete decomposition of organic matter caused by the insufficient temperature during outdoor open-air composting is solved. The method has a good application prospect in the field of waste composting.

Description

Technical Field

[0001] This invention relates to the field of garden waste resource utilization technology, and in particular to a method for the resource utilization of outdoor garden waste. Background Technology

[0002] Garden waste consists of plant residues such as branches and leaves generated during garden maintenance, primarily composed of lignin, cellulose, and hemicellulose. Traditionally, garden waste has been disposed of mainly through incineration or landfill, resulting in a significant waste of valuable biomass resources. As a type of organic waste, the resource-based treatment and utilization of garden waste is an effective means of implementing national requirements for carbon neutrality, ecological civilization, and green development, promoting the development of new productive forces, and playing a vital role in alleviating waste disposal pressure and maintaining ecosystem stability.

[0003] Composting is an efficient and sustainable way to utilize garden waste. Essentially, under dynamic temperature control, organic matter gradually decomposes into small organic molecules such as amino acids and monosaccharides through the action of microorganisms. Some of these small organic molecules continue to decompose and mineralize into carbon dioxide and water, while the rest, through the synergistic action of microorganisms and their secreted extracellular enzymes, undergoes humification to form complex and stable macromolecular humus. The entire composting process can be divided into a heating phase, a thermophilic phase, and a cooling phase, with microbial activity and material transformation closely coupled at each stage. After the heating phase, when the compost temperature reaches approximately 50°C, it enters the thermophilic phase. At this time, mesophilic microorganisms are replaced by thermophilic microorganisms. Lactase and lignin peroxidase, secreted by these microorganisms, use H2O2 or O2 as electron acceptors to break linkages, completing the demethylation of aromatic hydrocarbon structures and leading to the rapid degradation of recalcitrant macromolecular organic matter such as cellulose and lignin. Simultaneously, the material transformation rate in the compost reaches its peak, and the compost enters a period of high-efficiency degradation, while pathogens are also killed under the high-temperature environment. Therefore, the high-temperature period is the critical stage of composting. If the temperature is insufficient, the composting will remain in the mesophilic stage, only decomposing simple substances such as sugars and starches, failing to destroy pathogens and lignin, resulting in a long composting cycle and incomplete decomposition of organic matter. Conventional composting methods can generally ensure that the compost reaches the desired temperature by adjusting the carbon-nitrogen ratio of the raw materials, inoculating with functional microbial agents, and using a film covering for insulation. However, when composting in low-temperature outdoor environments, it is still difficult to reach the ideal temperature range, leading to long composting times and incomplete decomposition.

[0004] Therefore, there is a need to find an outdoor composting method for garden waste to solve the problems of low compost temperature, long composting time, and incomplete decomposition of organic matter during outdoor composting of garden waste. Summary of the Invention

[0005] Therefore, the purpose of this invention is to provide a method for the resource utilization of outdoor garden waste, which solves the problems of low compost temperature, long composting time, and incomplete decomposition of organic matter during outdoor composting of garden waste.

[0006] The present invention solves the above-mentioned technical problems through the following technical means:

[0007] A method for the resource utilization of outdoor garden waste, the method comprising the following steps:

[0008] (1) Collect garden waste, remove impurities and crush it to a particle size ≤5cm to obtain raw material residue;

[0009] (2) Adjust the carbon-nitrogen ratio of the raw material slag to (25-30):1, adjust the moisture content to 50-60%, and adjust the pH to 6.5-7.5 to obtain the stockpile;

[0010] (3) Add compound microbial agent to the compost and mix evenly, then add heating particles and mix evenly, then pile up and cover with film for fermentation. Turn the pile over once every 10 days until the temperature of the pile drops to room temperature and remains stable and there is no obvious odor, indicating that the composting is complete and organic fertilizer is obtained.

[0011] Furthermore, the composite microbial agent is obtained by mixing Bacillus subtilis and Trichoderma viride in a mass ratio of 2:1; the viable count of both Bacillus subtilis and Trichoderma viride in the composite microbial agent is 1 to 5 × 10⁻⁶. 9 CFU / g.

[0012] Furthermore, the mass ratio of the stockpile material to the composite microbial agent is 100:(0.1-0.3); the mass ratio of the stockpile material to the heating particles is 100:(8-12).

[0013] Furthermore, the heating particles comprise the following raw materials:

[0014] Bentonite, zeolite powder, calcium chloride, sodium carboxymethyl cellulose, reduced iron powder, activated carbon, calcium peroxide, trehalose, maleic anhydride, polyethylene glycol, sodium gluconate.

[0015] Furthermore, the method for preparing the heating particles is as follows:

[0016] The method for preparing the heating particles is as follows:

[0017] A: Mix bentonite, zeolite powder and calcium chloride with a particle size of 70 mesh evenly, then add 1 wt% sodium carboxymethyl cellulose solution and mix evenly. Granulate the mixture to obtain particles with a particle size of 4-5 cm. Let it stand overnight and then dry it at 80℃ for 4-6 hours. Then soak it in water for 12-18 hours, filter to remove the filtrate, and then dry it at 80℃ for 4-6 hours to obtain a porous carrier.

[0018] B: Add reduced iron powder and activated carbon to water, and mix them under sealed stirring at 800-1000 r / min for 15-20 min. Then add sodium carboxymethyl cellulose, stir and mix evenly, and then grind and pulverize to a particle size ≤50μm. Then vacuum dry at 60℃ for 4-5 h, and then put it into a trehalose-maleic anhydride mixture, soak for 2-3 min, and then take it out and dry at 45℃ for 15-30 min to obtain mixed microparticles.

[0019] C: Add the porous carrier, mixed microparticles, and calcium peroxide to water and stir to disperse. Vacuum the water to -0.095 MPa and maintain the vacuum for 15-30 minutes to allow the calcium peroxide and mixed microparticles to enter the interior of the porous carrier. Then, slowly release the vacuum and vacuum dry the porous carrier loaded with calcium peroxide and mixed microparticles at 60°C for 1-2 hours to obtain the loaded particles.

[0020] D: Heat polyethylene glycol to 60°C and stir to melt it. Then add sodium gluconate and mix evenly to obtain polyethylene glycol-sodium gluconate complex. Place the loaded particles in a roller coating machine, heat the roller to 60°C and slowly add polyethylene glycol-maleic anhydride complex at 5% of the mass of the loaded particles. Coat for 10 minutes at a speed of 20 r / min, and then cool naturally to room temperature to obtain heating particles.

[0021] Furthermore, in step A, the mass ratio of bentonite, zeolite powder, calcium chloride, and sodium carboxymethyl cellulose solution is (15-20): (5-10): (4-5): (4-6).

[0022] Furthermore, in step B, the mass ratio of reduced iron powder, activated carbon, and sodium carboxymethyl cellulose is (1-2):(2-4):(0.006-0.01).

[0023] Furthermore, in step B, the trehalose-maleic anhydride mixture is obtained by mixing 10wt% trehalose solution and 10wt% maleic anhydride solution in a mass ratio of 1:1.

[0024] Furthermore, in step C, the mass ratio of porous carrier, mixed microparticles, and calcium peroxide is (20-30):(3-6):(0.2-0.4).

[0025] Furthermore, in step D, the mass ratio of polyethylene glycol to sodium gluconate is 2:1.

[0026] Outdoor composting of garden waste is challenging due to low outdoor temperatures, making it difficult to reach the optimal medium-to-high temperature for composting. This results in prolonged composting time and incomplete decomposition. Therefore, this invention introduces heating particles added to the compost pile. These particles release heat to raise the pile temperature, accelerating the composting process and improving compost quality. Specifically, the heating particles use iron powder as a heat source, releasing heat through an oxidation-reduction reaction, thereby increasing the pile temperature.

[0027] However, adding iron powder directly to the compost pile presents several challenges. First, the iron powder's short heating time is insufficient for the required composting time. Second, directly adding iron powder makes it difficult to control the pile temperature; the large amount of heat released during iron powder oxidation can lead to excessively high temperatures, inhibiting microbial activity and hindering the composting process. Furthermore, the direct entry of iron powder oxidation products into the compost results in excessively high iron content, which, when applied to the soil, can inhibit plant growth. Reducing the amount of iron powder added does not effectively raise the composting temperature.

[0028] To address the aforementioned technical issues, this invention employs bentonite, zeolite powder, and calcium chloride to prepare a porous carrier. Reduced iron powder and activated carbon are then mixed into microparticles and loaded onto the porous carrier. Finally, polyethylene glycol (PEG) is used to seal the pores, resulting in the heating particles. Preparing mixed microparticles from iron powder and activated carbon, and then loading them onto the porous carrier, effectively reduces the contact rate between the iron powder and oxygen / moisture, thereby reducing the reactive activity of iron powder oxidation and heat release, decreasing heat release, and extending the heating time. Simultaneously, PEG is a phase change material. When the heating particles release heat too quickly, PEG absorbs excessive heat and undergoes a phase change to store the heat. Then, as the pile temperature decreases, it releases the heat through another phase change. This not only maintains stable pile temperature and prevents excessively high temperatures from inhibiting microbial activity, but also reduces heat loss and improves the efficiency of the heating particles.

[0029] During the gradual oxidation and heat release process of iron powder, the oxidation products Fe(OH)3 or Fe2O3 easily coat the surface of unreacted iron powder, forming a passivation layer. This hinders further contact between oxygen, moisture, and unreacted iron powder, reducing the effectiveness of the iron powder and shortening the heating time. Therefore, this invention prepares a trehalose-maleic anhydride mixture to treat the mixed particles. Trehalose can form a water-permeable, oxygen-permeable, and water-absorbing film on the surface of the mixed particles, further slowing down the contact rate between external oxygen and moisture and the iron powder, thus extending the heating time. Meanwhile, maleic anhydride can hydrolyze and release maleic acid to dissolve the oxidation products of the iron powder, ensuring that moisture and oxygen further react with the unreacted iron powder, thereby continuously and stably releasing heat and ensuring the effectiveness and duration of the iron powder's action.

[0030] Beneficial effects:

[0031] This invention prepares heating particles that are mixed into compost. The heating particles can continuously, slowly, and stably release heat to increase the temperature of the compost pile, ensuring that the temperature can reach the required fermentation temperature when composting outdoors in low-temperature environments. This shortens the fermentation time, promotes the decomposition of organic matter, and thus ensures the efficiency of composting and the quality of compost products. Detailed Implementation

[0032] The present invention will be described in detail below with reference to specific embodiments:

[0033] This invention requires the preparation of heating particles before composting garden waste, as detailed below. The reduced iron powder used has a purity ≥98%; the polyethylene glycol used is PEG-4000.

[0034] Example 1: Preparation of Heating Particles

[0035] A: Mix 17kg bentonite, 8kg zeolite powder and 4.5kg calcium chloride with a particle size of 70 mesh evenly, then add 5kg of 1wt% sodium carboxymethyl cellulose solution and mix evenly. Granulate the mixture to obtain particles with a particle size of 5cm. Let it stand overnight and then dry it at 80℃ for 5h. Then soak it in water for 16h, filter to remove the filtrate, and then dry it at 80℃ for 5h to obtain a porous carrier.

[0036] B: Add 1.5 kg of reduced iron powder and 3 kg of activated carbon to 9 kg of water, and mix them under sealed conditions at 900 r / min for 18 min. Then add 0.008 kg of sodium carboxymethyl cellulose, mix them evenly, and then grind them under sealed conditions until the particle size is ≤50 μm. After drying under vacuum at 60℃ for 4.5 h, put them into a trehalose-maleic anhydride mixture obtained by mixing 10 wt% trehalose solution and 10 wt% maleic anhydride solution in a mass ratio of 1:1. Soak for 2.5 min, then take them out and dry them at 45℃ for 25 min to obtain mixed microparticles.

[0037] C: Add 25 kg of porous carrier, 4.5 kg of mixed microparticles and 0.3 kg of calcium peroxide to 29.5 kg of water and stir to disperse. Vacuum the mixture to -0.095 MPa and maintain the vacuum for 20 min to allow the calcium peroxide and mixed microparticles to enter the porous carrier. Then slowly release the vacuum and vacuum dry the porous carrier loaded with calcium peroxide and mixed microparticles at 60 °C for 1.5 h to obtain the loaded particles.

[0038] D: Heat polyethylene glycol to 60°C and stir to melt it. Then add sodium gluconate in a mass ratio of polyethylene glycol:sodium gluconate = 2:1 and mix evenly to obtain polyethylene glycol-sodium gluconate complex. Place the loaded particles in a roller coating machine, heat the roller to 60°C and slowly add polyethylene glycol-maleic anhydride complex at 5% of the mass of the loaded particles. Coat at 20 r / min for 10 min and then cool naturally to room temperature to obtain heating particles.

[0039] Example 2: Preparation of Heating Particles

[0040] A: Mix 15kg bentonite, 5kg zeolite powder and 4kg calcium chloride with a particle size of 70 mesh evenly, then add 4kg of 1wt% sodium carboxymethyl cellulose solution and mix evenly to form particles with a particle size of 4cm. After standing overnight, dry at 80℃ for 4h, then soak in water for 12h, filter to remove the filtrate, and then dry at 80℃ for 4h to obtain a porous carrier.

[0041] B: Add 1 kg of reduced iron powder and 2 kg of activated carbon to 6 kg of water, and mix them under sealed conditions at 800 r / min for 15 min. Then add 0.006 kg of sodium carboxymethyl cellulose, mix them evenly, and then grind them under sealed conditions until the particle size is ≤50 μm. After drying under vacuum at 60℃ for 4 h, put them into a trehalose-maleic anhydride mixture obtained by mixing 10 wt% trehalose solution and 10 wt% maleic anhydride solution in a mass ratio of 1:1. Soak for 2 min, then take them out and dry them at 45℃ for 15 min to obtain mixed microparticles.

[0042] C: Add 20kg of porous carrier, 3kg of mixed microparticles and 0.2kg of calcium peroxide to 23kg of water and stir to disperse. Vacuum the container to -0.095MPa and maintain the vacuum for 15min to allow the calcium peroxide and mixed microparticles to enter the interior of the porous carrier. Then slowly release the vacuum and vacuum dry the porous carrier loaded with calcium peroxide and mixed microparticles at 60℃ for 1h to obtain the loaded particles.

[0043] D: Heat polyethylene glycol to 60°C and stir to melt it. Then add sodium gluconate in a mass ratio of polyethylene glycol:sodium gluconate = 2:1 and mix evenly to obtain polyethylene glycol-sodium gluconate complex. Place the loaded particles in a roller coating machine, heat the roller to 60°C and slowly add polyethylene glycol-maleic anhydride complex at 5% of the mass of the loaded particles. Coat at 20 r / min for 10 min and then cool naturally to room temperature to obtain heating particles.

[0044] Example 3: Preparation of Heating Particles

[0045] A: Mix 20kg bentonite, 10kg zeolite powder and 5kg calcium chloride with a particle size of 70 mesh evenly, then add 6kg of 1wt% sodium carboxymethyl cellulose solution and mix evenly. Granulate the mixture to obtain particles with a particle size of 5cm. Let it stand overnight and then dry it at 80℃ for 6h. Then soak it in water for 18h, filter to remove the filtrate, and then dry it at 80℃ for 6h to obtain a porous carrier.

[0046] B: Add 2 kg of reduced iron powder and 4 kg of activated carbon to 12 kg of water, and mix them under sealed conditions at 1000 r / min for 15 min. Then add 0.01 kg of sodium carboxymethyl cellulose, mix them evenly, and then grind them under sealed conditions until the particle size is ≤50 μm. After drying under vacuum at 60℃ for 5 h, put them into a trehalose-maleic anhydride mixture obtained by mixing 10 wt% trehalose solution and 10 wt% maleic anhydride solution in a mass ratio of 1:1. Soak for 3 min, then take them out and dry them at 45℃ for 30 min to obtain mixed microparticles.

[0047] C: Add 30kg of porous carrier, 6kg of mixed microparticles and 0.4kg of calcium peroxide to 36kg of water and stir to disperse. Vacuum the container to -0.095MPa and maintain the vacuum for 30min to allow the calcium peroxide and mixed microparticles to enter the interior of the porous carrier. Then slowly release the vacuum and vacuum dry the porous carrier loaded with calcium peroxide and mixed microparticles at 60℃ for 2h to obtain the loaded particles.

[0048] D: Heat polyethylene glycol to 60°C and stir to melt it. Then add sodium gluconate in a mass ratio of polyethylene glycol:sodium gluconate = 2:1 and mix evenly to obtain polyethylene glycol-sodium gluconate complex. Place the loaded particles in a roller coating machine, heat the roller to 60°C and slowly add polyethylene glycol-maleic anhydride complex at 5% of the mass of the loaded particles. Coat at 20 r / min for 10 min and then cool naturally to room temperature to obtain heating particles.

[0049] Comparative Example 1: Preparation of Heating Particles

[0050] Compared with Example 1, the only difference is that in the preparation of the heating particles in Comparative Example 1, the mixed microparticles in step B were not treated with a trehalose-maleic anhydride mixture, but were directly ground and pulverized and then vacuum dried to obtain the mixed microparticles, as shown below:

[0051] (1) Same as Example 1;

[0052] (2) Add 1.5 kg of reduced iron powder and 3 kg of activated carbon to 9 kg of water, and mix them under sealed stirring at 900 r / min for 18 min. Then add 0.008 kg of sodium carboxymethyl cellulose, mix them evenly, and then seal and grind them to a particle size ≤ 50 μm. Then vacuum dry them at 60℃ for 4.5 h to obtain mixed microparticles.

[0053] (3) Same as in Example 1.

[0054] Comparative Example 2: Preparation of Heating Particles

[0055] In contrast to Example 1, the only difference in Comparative Example 2 is that in step B of the preparation of the heating particles, only a trehalose solution was used for further treatment, instead of a trehalose-maleic anhydride mixture, as detailed below:

[0056] (1) Same as Example 1;

[0057] (2) Add 1.5 kg of reduced iron powder and 3 kg of activated carbon to 9 kg of water, and mix them under sealed stirring at 900 r / min for 18 min. Then add 0.008 kg of sodium carboxymethyl cellulose, mix them evenly, and then grind them under sealed grinding until the particle size is ≤50 μm. Then vacuum dry them at 60℃ for 4.5 h and put them into 10 wt% trehalose solution. Soak them for 2.5 min and then take them out and dry them at 45℃ for 25 min to obtain mixed microparticles.

[0058] (3) Same as in Example 1.

[0059] Comparative Example 3: Preparation of Heating Particles

[0060] Compared with Example 1, the only difference is that step D was missing in the preparation of the heating particles in Comparative Example 3. The loaded particles prepared directly from steps A, B and C are the heating particles.

[0061] Comparative Example 4: Preparation of Heating Particles

[0062] In contrast to Example 1, the only difference is that in Comparative Example 4, sodium gluconate was not added in step D during the preparation of the heating particles; instead, polyethylene glycol was used for treatment, as detailed below:

[0063] (1) to (2) are the same as in Example 1;

[0064] (3) Heat polyethylene glycol to 60°C and stir to melt it. Place the loaded particles in a roller coating machine, heat the roller to 60°C and slowly add the molten polyethylene glycol. The amount added is 5% of the mass of the loaded particles. Coat for 10 minutes at a speed of 20 r / min, and then cool naturally to room temperature to obtain the heating particles.

[0065] Comparative Example 5: Preparation of Heating Particles

[0066] Compared with Example 1, the only difference is that in Comparative Example 5, the mass ratio of polyethylene glycol to sodium gluconate in step D during the preparation of the heating particles is 4:1, while the other steps are the same as in Example 1.

[0067] Example 4: Method for Resource Utilization of Garden Waste

[0068] (1) Collect garden waste, remove plastic bags, stones and other debris, and crush it to a particle size ≤5cm to obtain raw material residue;

[0069] (2) Adjust the carbon-nitrogen ratio of the raw material slag to 26:1, adjust the moisture content to 55%, and adjust the pH to 7 to obtain the stockpile;

[0070] (3) A compound microbial agent was prepared by mixing Bacillus subtilis and Trichoderma viride at a mass ratio of 2:1. The compound microbial agent was added to the stockpile at a mass ratio of stockpile:compound microbial agent = 100:0.2 and mixed evenly. The viable count of Bacillus subtilis and Trichoderma viride in the compound microbial agent was approximately 1×10⁻⁶. 9 CFU / g, then add the heating particles from Example 3 according to the mass ratio of compost:heating particles = 100:10, mix evenly, then stack to prepare a trapezoidal stack with a width of 1.5m and a height of 1m, and then cover with a film for fermentation. Turn the stack over every 10 days until the temperature of the stack drops to room temperature and remains stable and there is no obvious odor, indicating that the composting is complete and organic fertilizer is obtained.

[0071] Experiment: Composting Experiment of Garden Waste

[0072] 1. A composting experiment on the resource utilization of garden waste was conducted at Xi'an Botanical Garden, Shaanxi Province. The experiment was divided into 7 groups: experimental group 1, control groups 1-5, and blank control group. Experimental group 1 used the composting method of Example 4 and the heating particles of Example 1; control groups 1-5 used the heating particles prepared by comparative examples 1-5 and the composting method of Example 4, respectively; the blank control group did not add heating particles, and the other composting methods were carried out according to Example 4.

[0073] 2. The experiment was conducted in November during winter. Garden waste was used as pruned branches. Each group used 100 kg of compost residue. The carbon-nitrogen ratio of the compost was adjusted to 26:1, the moisture content was 55%, and the pH was 7. The temperature of the compost pile on the 5th, 15th, and 20th days of each group was measured and recorded. The highest temperature of the compost pile and the composting time of each group were also recorded. The seed germination index (cucumber seeds) of the compost product of each group was also measured. Three replicate experiments were conducted, and the data are shown in Table 1.

[0074] Table 1

[0075]

[0076] Based on the data analysis in Table 1, we can conclude that:

[0077] (1) After adding the heating particles prepared according to the present invention, the temperature of the compost pile in experimental group 1 reached 45.6℃ on the 5th day, entering the meso-temperature composting stage. On the 15th and 20th days, the temperature remained at around 59℃, entering the high-temperature composting stage. In contrast, without the addition of heating particles, the temperature of the compost pile in the blank control group was only 39.3℃ on the 5th day, not yet entering the meso-temperature composting stage. On the 15th and 20th days, the temperature was around 51℃, not yet in the high-temperature composting stage. This indicates that adding the heating particles prepared according to the method of the present invention to the compost pile can continuously increase the temperature of the compost pile, which is beneficial to promoting the composting process. The composting time of experimental group 1 was only 34 days, and the germination index of the organic fertilizer reached 95.4%. In contrast, the composting time of the blank control group increased to 49 days, and the germination index of the organic fertilizer was 79.3%. This indicates that composting with heating particles prepared according to the method of the present invention can shorten the composting time while increasing the degree of composting of the organic fertilizer obtained from fermentation, resulting in organic fertilizer with good application prospects.

[0078] (2) In the preparation of the heating particles in control group 1, the mixed microparticles were not treated with trehalose-maleic anhydride mixture. The lack of trehalose film formation delayed the reaction of the mixed microparticles, resulting in a decrease in the effect of the heating particles in the middle and later stages. In addition, the lack of maleic anhydride to promote the reaction of iron powder limited the exothermic reaction of iron powder, thus reducing the effect of the heating particles.

[0079] (3) In the control group 3, polyethylene glycol and sodium gluconate were not used for the preparation of the heating particles. The lack of polyethylene glycol as a phase change material reduced the heat utilization rate of the heating particles. In the experimental group 1, polyethylene glycol and sodium gluconate were used for sealing treatment. On the one hand, polyethylene glycol phase change material sealed the pores to inhibit the entry of air and water in the early stage, thereby inhibiting the heat release of the iron powder inside in the early stage. The mixed sodium gluconate, as a good carbon source for microorganisms, was decomposed and utilized. After the sealing structure was partially pored, oxygen and water entered, and the iron powder began to react and release heat. Then, after the temperature reached the polyethylene glycol phase change point, the pores increased, allowing a large amount of oxygen and water to enter. At this time, the iron powder released a large amount of heat, making the maximum temperature of the pile reach 64.3℃, which ensured the efficient killing of pathogens in the compost and improved the effect of the heating particles. At the same time, sodium gluconate can complex and fix the iron powder oxidation products, so even if the obtained organic fertilizer is applied to the soil, it will not cause plants to absorb a large amount of iron and affect the normal growth of plants. The obtained organic fertilizer can slowly and continuously release iron elements, which can be preferentially used for iron-loving plants and iron-deficient soils.

[0080] (4) No sodium gluconate was added during the preparation of the heating particles in control group 4, and the amount of sodium gluconate was too low during the preparation of the heating particles in control group 5. The lack of sodium gluconate as a good carbon source in control groups 4 and 5 resulted in low activity of microorganisms, which affected fermentation and maturation, and delayed the opening of the sealing structure. Therefore, the temperature on the 5th day was significantly reduced. In addition, the low amount of sodium gluconate reduced the iron fixation effect and limited the application of organic fertilizer.

[0081] 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 preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the present invention, and all such modifications and substitutions should be covered within the scope of the claims of the present invention. Technical aspects, shapes, and structures not described in detail in this invention are all well-known technologies.

Claims

1. A method for the resource utilization of outdoor garden waste, characterized in that, The method includes the following steps: (1) Collect garden waste, remove impurities and crush it to a particle size ≤5cm to obtain raw material residue; (2) Adjust the carbon-nitrogen ratio of the raw material slag to (25-30):1, adjust the moisture content to 50-60%, and adjust the pH to 6.5-7.5 to obtain the stockpile; (3) Add compound microbial agent to the compost and mix evenly, then add heating particles and mix evenly, then pile up and cover with film for fermentation. Turn the pile over once every 10 days until the temperature of the pile drops to room temperature and remains stable and there is no obvious odor, indicating that the composting is complete and organic fertilizer is obtained.

2. The method for resource utilization of outdoor garden waste according to claim 1, characterized in that, The composite microbial agent is obtained by mixing Bacillus subtilis and Trichoderma viride in a mass ratio of 2:1; the viable count of both Bacillus subtilis and Trichoderma viride in the composite microbial agent is 1 to 5 × 10⁻⁶. 9 CFU / g.

3. The method for resource utilization of outdoor garden waste according to claim 2, characterized in that, The mass ratio of the stockpile material to the compound microbial agent is 100:(0.1-0.3); the mass ratio of the stockpile material to the heating particles is 100:(8-12).

4. The method for resource utilization of outdoor garden waste according to claim 3, characterized in that, The heating particles comprise the following raw materials: Bentonite, zeolite powder, calcium chloride, sodium carboxymethyl cellulose, reduced iron powder, activated carbon, calcium peroxide, trehalose, maleic anhydride, polyethylene glycol, sodium gluconate.

5. The method for resource utilization of outdoor garden waste according to claim 4, characterized in that, The method for preparing the heating particles is as follows: A: Mix bentonite, zeolite powder and calcium chloride with a particle size of 70 mesh evenly, then add 1 wt% sodium carboxymethyl cellulose solution and mix evenly. Granulate the mixture to obtain particles with a particle size of 4-5 cm. Let it stand overnight and then dry it at 80℃ for 4-6 hours. Then soak it in water for 12-18 hours, filter to remove the filtrate, and then dry it at 80℃ for 4-6 hours to obtain a porous carrier. B: Add reduced iron powder and activated carbon to water, and mix them under sealed stirring at 800-1000 r / min for 15-20 min. Then add sodium carboxymethyl cellulose, stir and mix evenly, and then grind and pulverize to a particle size ≤50μm. Then vacuum dry at 60℃ for 4-5 h, and then put it into a trehalose-maleic anhydride mixture, soak for 2-3 min, and then take it out and dry at 45℃ for 15-30 min to obtain mixed microparticles. C: Add the porous carrier, mixed microparticles, and calcium peroxide to water and stir to disperse. Vacuum the water to -0.095 MPa and maintain the vacuum for 15-30 minutes to allow the calcium peroxide and mixed microparticles to enter the interior of the porous carrier. Then, slowly release the vacuum and vacuum dry the porous carrier loaded with calcium peroxide and mixed microparticles at 60°C for 1-2 hours to obtain the loaded particles. D: Heat polyethylene glycol to 60°C and stir to melt it. Then add sodium gluconate and mix evenly to obtain polyethylene glycol-sodium gluconate complex. Place the loaded particles in a roller coating machine, heat the roller to 60°C and slowly add polyethylene glycol-maleic anhydride complex at 5% of the mass of the loaded particles. Coat for 10 minutes at a speed of 20 r / min, and then cool naturally to room temperature to obtain heating particles.

6. The method for resource utilization of outdoor garden waste according to claim 5, characterized in that, In step A, the mass ratio of bentonite, zeolite powder, calcium chloride, and sodium carboxymethyl cellulose solution is (15-20): (5-10): (4-5): (4-6).

7. A method for resource utilization of outdoor garden waste according to claim 6, characterized in that, In step B, the mass ratio of reduced iron powder, activated carbon, and sodium carboxymethyl cellulose is (1-2):(2-4):(0.006-0.01).

8. A method for resource utilization of outdoor garden waste according to claim 7, characterized in that, In step B, the trehalose-maleic anhydride mixture is obtained by mixing 10wt% trehalose solution and 10wt% maleic anhydride solution in a mass ratio of 1:

1.

9. A method for resource utilization of outdoor garden waste according to claim 8, characterized in that, In step C, the mass ratio of porous carrier, mixed microparticles, and calcium peroxide is (20-30):(3-6):(0.2-0.4).

10. A method for resource utilization of outdoor garden waste according to claim 9, characterized in that, In step D, the mass ratio of polyethylene glycol to sodium gluconate is 2:1.

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