Aerobic composting process for garden plant waste

Abstract

The invention relates to the technical field of organic waste treatment and resource utilization, in particular to an aerobic composting process for garden plant waste. The garden plant waste aerobic composting process provided by the invention can effectively solve the problems of long composting period, low decomposition degree, serious nitrogen loss, high secondary pollution risk and the like in the existing composting process, and realizes efficient and environment-friendly treatment and resource utilization of the garden plant waste; compared with a traditional fixed turning period mode, the turning control can better adapt to the requirements of different stages in the composting process, and the composting efficiency and quality are improved; besides, the garden plant waste is converted into high-quality organic fertilizer, resource utilization of the waste is achieved, dependence on chemical fertilizer is reduced, and good economic benefits, environmental benefits and social benefits are achieved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of organic waste treatment and resource utilization, in particular to an aerobic composting process of garden plant waste. BACKGROUND

[0002] With the acceleration of urbanization and the increasing demand for ecological environment, the scale of urban garden construction is expanding, and the amount of garden plant waste generated is also growing. According to statistics, the garden plant waste generated in some cities in China can reach hundreds of thousands of tons per year. At present, the main disposal methods of garden plant waste are incineration, landfill and composting, etc. Incineration will produce a large amount of carbon dioxide, sulfur dioxide, nitrogen oxides and dioxin, etc. harmful substances, causing serious pollution to the atmospheric environment; landfill not only occupies a large amount of land resources, but also the decomposition of waste in the landfill site is slow, and the leachate may pollute the soil and groundwater.

[0003] As a relatively environmentally friendly disposal method, aerobic composting can decompose and transform the organic matter in garden plant waste into stable humus through the aerobic respiration of microorganisms, forming organic fertilizer. However, the existing aerobic composting process has many problems: first, the single or unreasonable combination of microbial strains leads to low decomposition efficiency of complex organic components (such as cellulose, lignin, etc.) in garden plant waste, and the composting period is as long as 40-60 days. Second, it is difficult to accurately control the key parameters (such as temperature, humidity, oxygen concentration, carbon-nitrogen ratio, etc.) in the composting process, which affects the activity and metabolism of microorganisms and reduces the composting quality. Third, the ventilation system is not reasonably designed, and the oxygen distribution in the pile is uneven, which can easily cause local anaerobic environment and produce foul-smelling gases (such as ammonia, hydrogen sulfide, etc.), causing secondary pollution. Fourth, there is a lack of scientific and accurate method for determining the maturity, and the quality of the compost product is unstable, which cannot meet the demand of agricultural production for high-quality organic fertilizer.

[0004] Therefore, it is urgent to develop a new aerobic composting process of garden plant waste to solve the above problems. SUMMARY

[0005] The present application aims to provide an aerobic composting process of garden plant waste to solve the problems of long composting period, low maturity, serious nitrogen loss and high risk of secondary pollution in the existing composting process, and to realize efficient and environmentally friendly treatment and resource utilization of garden plant waste.

[0006] To achieve the above-mentioned purpose, the present application provides the following technical solutions: An aerobic composting process of garden plant waste, comprising the following steps: Step one, the garden plant waste is classified to remove impurities, the garden waste after impurity removal is sequentially cleaned and dried, and then crushed into a mixture with a particle size of ≤5 cm, the obtained mixture is stored after regulation and optimization, and used; Step two, inoculating a compound microbial inoculant into the mixture after regulation and optimization, wherein the compound microbial inoculant is compounded by cellulose-decomposing bacteria, lignin-decomposing bacteria, nitrogen-fixing bacteria and yeast bacteria at a mass ratio of 1.5-2.5:2-3:1:1-1.5; Step three, after inoculating the compound microbial inoculant, the mixture is stacked into a trapezoidal stack with a height of 1.5-2 m, a width of 2-3 m, and a length determined by the site; wherein the trapezoidal stack is provided with a ventilation pipe, the interval of the ventilation pipe is 1-1.5 m, the pipe wall is uniformly distributed with ventilation holes, and the hole diameter is 0.5-1 cm; Step four, turn over the heap every 2-3 days at the initial stage of composting, and monitor and adjust the oxygen concentration and pH value in real time; when the temperature of the trapezoidal stack is higher than 60℃ and stable for 2-3 days, turn over the heap every 5-7 days until the temperature of the trapezoidal stack drops to below 40℃ and does not rise again; Step five, when the color of the trapezoidal compost material changes to black-brown, the texture is loose, and there is no foul odor, the composted compost material is sequentially screened, dried and packaged, and the garden plant waste aerobic compost is obtained.

[0007] Further, the regulation and optimization process includes humidity regulation and carbon-nitrogen ratio regulation, and the humidity of the mixture is regulated to 50-60%, and the carbon-nitrogen ratio is regulated to 25-30:1.

[0008] Further, the cellulose-decomposing bacteria are selected from Trichoderma viride, and the lignin-decomposing bacteria are selected from Phanerochaete chrysosporium.

[0009] Further, the material of the ventilation pipe in step three is any one of polyvinyl chloride and polyethylene, and the pipe diameter is 5-10 cm.

[0010] Further, when regulating the carbon-nitrogen ratio, the carbon source is selected from sawdust, and the nitrogen source is selected from chicken manure.

[0011] Further, the screening process uses a screen with a hole diameter of 6-10 mm, the drying temperature is 50-60℃, and the water content of the compost material after drying is ≤15%.

[0012] Further, the specific operation of real-time monitoring of oxygen concentration is: when the oxygen concentration is ≤18%, increase the ventilation volume; when the oxygen concentration is ≥22%, reduce the ventilation volume.

[0013] Further, the specific operation of monitoring the pH value in real time is that when the pH value is lower than 6.5, lime is added; when the pH value is higher than 8.5, calcium superphosphate is added, so that the pH value is kept in the range of 6.5-8.5.

[0014] Further, the composting determination standard further comprises that a seed germination index (GI) is greater than or equal to 90%, an electrical conductivity (EC) is less than or equal to 3.5 mS / cm, and a ratio of ammonium nitrogen to nitrate nitrogen (NH4 + -N / NO3 ～ -N) is in the range of 0.2-0.5.

[0015] Further, the inoculation amount of the compound microbial agent is 0.5-1% of the total mass of the mixed material, and the compound microbial agent is uniformly sprayed on the surface of the mixed material in the form of atomization, and then uniformly mixed and stirred.

[0016] Compared with the prior art, the beneficial effects of the present application are: 1. Compared with the traditional single microbial agent or simple mixed microbial agent, the compound microbial agent provided by the present application can fully exert the synergistic effect of each strain. The cellulose-decomposing bacteria and the lignin-decomposing bacteria can rapidly decompose the complex organic matter in the garden plant waste, thereby shortening the composting time. The nitrogen-fixing bacteria can effectively fix the nitrogen in the air, thereby reducing the loss of nitrogen in the form of ammonia gas and the like, and improving the nitrogen content of the compost product. The yeast improves the fermentation environment and promotes the growth and metabolism of other microorganisms, thereby improving the composting degree and the fertilizer efficiency. The organic matter content, the humic acid content and the nitrogen, phosphorus and potassium content of the fertilizer produced by the present application are all significantly improved, the fertilizer efficiency is better, and the fertilizer can meet the needs of different soils and crops.

[0017] 2. The ventilation pipe is arranged in the heap body, and the interval, pipe diameter and ventilation hole of the ventilation pipe are optimally designed. In the traditional composting process, the ventilation pipe is often not reasonably arranged, which leads to uneven ventilation of the heap body and affects the composting effect. In the present application, the ventilation pipe is reasonably arranged, so that the oxygen supply in the heap body is sufficient and uniform, the activity of aerobic microorganisms is maintained, the generation of local anaerobic environment is avoided, the emission of harmful gases such as ammonia and hydrogen sulfide is reduced, and the risk of secondary pollution is reduced. At the same time, the generation of leachate is also reduced, and the pollution risk of soil and groundwater is reduced. In addition, the composting process is also significantly accelerated, and the production efficiency of the fertilizer is improved.

[0018] 3. A specific turning schedule is developed based on temperature fluctuations. In the early stages of composting, microbial activity is high, requiring frequent turning to replenish oxygen. Once the compost temperature reaches a high temperature and stabilizes, the turning frequency is appropriately reduced to maintain microbial activity while preventing heat and water loss caused by excessive turning. Compared to traditional fixed turning cycles, the turning control of this invention better adapts to the needs of different stages of the composting process, improving composting efficiency and quality.

[0019] 4. Converting garden plant waste into high-quality organic fertilizer realizes the resource utilization of waste, reduces dependence on chemical fertilizers, and has good economic, environmental and social benefits. DETAILED DESCRIPTION

[0020] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of the present invention.

[0021] Example 1 An aerobic composting process for garden plant waste comprises the following steps: Step 1: Classify the garden plant waste to remove impurities therein, wash and dry the removed garden waste in turn, and then crush it into a mixed material with a particle size of 5 cm. The obtained mixed material is regulated and optimized and then stored for future use; The control optimization process includes humidity control and carbon-nitrogen ratio control, and the humidity of the mixed material is controlled to 50%, and the carbon-nitrogen ratio is controlled to 25:1; when adjusting the carbon-nitrogen ratio, sawdust is selected as the carbon source, and chicken manure is selected as the nitrogen source; Step 2: inoculating a composite microbial agent into the optimized mixture, wherein the composite microbial agent is composed of cellulose decomposing bacteria, lignin decomposing bacteria, nitrogen-fixing bacteria and yeast in a mass ratio of 1.5:2:1:1; The cellulolytic bacteria selected are Trichoderma viride, and the lignin decomposing bacteria selected are Phanerochaete chrysosporium; the inoculation amount of the composite microbial agent is 0.5% of the total mass of the mixed material, and the composite microbial agent is evenly sprayed on the surface of the mixed material by atomization, and then mixed and stirred evenly; Step 3: After inoculation with the composite microbial agent, the mixed materials are piled into a trapezoidal pile with a height of 1.5m, a width of 2m, and a length determined by the site; wherein, a ventilation pipe is installed inside the trapezoidal pile, the ventilation pipes are spaced 1m apart, and the ventilation holes with a diameter of 0.5cm are evenly distributed on the pipe wall; the ventilation pipe is made of polyvinyl chloride and has a diameter of 5cm; Step four, turn over the compost every 2 days in the early stage, monitor and adjust the oxygen concentration and pH value in real time; when the trapezoidal compost temperature is higher than 60℃ and stable for 2 days, turn over every 5 days until the trapezoidal compost temperature drops to below 40℃ and does not rise again; The specific operation of real-time monitoring of oxygen concentration is: when the oxygen concentration is ≤18%, increase the ventilation; when the oxygen concentration is ≥22%, reduce the ventilation; the pH value is monitored in real time to keep it at 6.5; Step five, when the color of the trapezoidal compost material changes to black brown, the texture is loose, and there is no foul odor, the composted compost material is sequentially screened, dried and packaged, and the garden plant waste aerobic compost is obtained; The screening process uses a screen with a pore size of 6mm, the drying temperature is 50℃, and the moisture content of the dried compost material is 15%; The composting criteria also include: seed germination index (GI) ≥90%, electrical conductivity (EC) ≤3.5mS / cm, ammonium nitrogen to nitrate nitrogen ratio (NH4 + -N / NO3 ～ -N) is 0.2.

[0022] Example 2 A kind of garden plant waste aerobic composting process, comprising the following steps: Step one, classify the garden plant waste to remove impurities, and the impurity-removed garden waste is sequentially washed and dried, and then crushed into a mixture with a particle size of 4cm, the obtained mixture is stored and used after being regulated and optimized; The regulation and optimization process includes humidity regulation and carbon-nitrogen ratio regulation, and the humidity of the mixture is regulated to 55% and the carbon-nitrogen ratio is regulated to 28:1; when regulating the carbon-nitrogen ratio, the carbon source is selected as sawdust and the nitrogen source is selected as chicken manure; Step two, inoculate the mixture after regulation and optimization with a compound microbial inoculant, wherein the compound microbial inoculant is compounded by cellulose-decomposing bacteria, lignin-decomposing bacteria, nitrogen-fixing bacteria and yeast bacteria in a mass ratio of 2:2.5:1:1; The cellulose-decomposing bacteria are selected as Trichoderma viride, and the lignin-decomposing bacteria are selected as Phanerochaete chrysosporium; the inoculation amount of the compound microbial inoculant is 0.8% of the total mass of the mixture, and the compound microbial inoculant is uniformly sprayed on the surface of the mixture by atomization, and then mixed and stirred uniformly; Step three, after inoculating the compound microbial inoculant, the mixture is stacked into a trapezoidal stack with a height of 1.8m, a width of 2.5m, and a length determined by the site; wherein the inside of the trapezoidal stack is provided with an air pipe, the air pipe is spaced 1.5m apart, the pipe wall is uniformly distributed with air holes, and the hole diameter is 1cm; the air pipe is made of polyethylene, and the pipe diameter is 8cm; Step four, turn over the compost every 3 days in the early stage, monitor and adjust the oxygen concentration and pH value in real time; when the trapezoidal compost temperature is higher than 60℃ and stable for 3 days, turn over every 6 days until the trapezoidal compost temperature drops to below 40℃ and does not rise again; The specific operation of real-time monitoring of oxygen concentration is: when the oxygen concentration is ≤18%, increase the ventilation; when the oxygen concentration is ≥22%, reduce the ventilation; the pH value is monitored in real time to keep it at 7.5; Step five, when the color of the trapezoidal compost material changes to black brown, the texture is loose, and there is no foul odor, the composted compost material is sequentially screened, dried and packaged, and the garden plant waste aerobic compost is obtained; The screening process uses a screen with a pore size of 8mm, the drying temperature is 55℃, and the moisture content of the dried compost material is 13%; The composting criteria also include: seed germination index (GI) ≥90%, electrical conductivity (EC) ≤3.5mS / cm, ammonium nitrogen to nitrate nitrogen ratio (NH4 + -N / NO3 ～ -N) is 0.4. Example 3 A kind of garden plant waste aerobic composting process, comprising the following steps: Step one, classify the garden plant waste to remove impurities, and the impurity-removed garden waste is sequentially washed and dried, and then crushed into a mixture with a particle size of 3cm, the obtained mixture is stored and used after being regulated and optimized; The regulation and optimization process includes humidity regulation and carbon-nitrogen ratio regulation, and the humidity of the mixture is regulated to 60% and the carbon-nitrogen ratio is regulated to 30:1; when regulating the carbon-nitrogen ratio, the carbon source is selected as sawdust and the nitrogen source is selected as chicken manure; Step two, inoculate the mixture after regulation and optimization with a compound microbial inoculant, wherein the compound microbial inoculant is compounded by cellulose-decomposing bacteria, lignin-decomposing bacteria, nitrogen-fixing bacteria and yeast bacteria in a mass ratio of 2.5:3:1:1.5; The cellulose-decomposing bacteria are selected as Trichoderma viride, and the lignin-decomposing bacteria are selected as Phanerochaete chrysosporium; the inoculation amount of the compound microbial inoculant is 1% of the total mass of the mixture, and the compound microbial inoculant is uniformly sprayed on the surface of the mixture by atomization, and then mixed and stirred uniformly; Step three, after inoculating the compound microbial inoculant, the mixture is stacked into a trapezoidal stack with a height of 2m, a width of 3m and a length determined by the site; wherein the inside of the trapezoidal stack is provided with an air pipe, the interval of the air pipe is 1.5m, the air holes are uniformly distributed on the pipe wall, and the hole diameter is 1cm; the material of the air pipe is polyvinyl chloride, and the pipe diameter is 10cm; Step four, turn over the heap every 3 days in the early stage of composting, monitor and adjust the oxygen concentration and pH value in real time; when the trapezoidal heap temperature is higher than 60 DEG C and stable for 3 days, turn over the heap every 7 days until the trapezoidal heap temperature drops to below 40 DEG C and does not rise again; The specific operation of monitoring the oxygen concentration in real time is: when the oxygen concentration is less than or equal to 18%, increase the ventilation; when the oxygen concentration is greater than or equal to 22%, reduce the ventilation; the pH value is monitored in real time to keep it at 8.5.

[0023] Step five, when the color of the trapezoidal compost material becomes black brown, the texture is loose, and there is no foul odor, the composted compost material is sequentially subjected to screening, drying and packaging treatment, and the garden plant waste aerobic compost is obtained; The screening process uses a screen with a pore size of 10 mm, the drying temperature is 60 DEG C, and the water content of the dried compost material is 12%; The composting determination standard also includes: seed germination index (GI) is greater than or equal to 90%, electrical conductivity (EC) is less than or equal to 3.5 mS / cm, and the ratio of ammonium nitrogen to nitrate nitrogen (NH4 + -N / NO3 ～ -N) is 0.5. Performance test: the relevant indicators of each fertilizer produced in examples 1-3 are detected as follows: 1. Carbon-nitrogen ratio: carbon content is determined by potassium dichromate oxidation-ferric sulfate titration, and nitrogen content is determined by Kjeldahl method. 2. Organic matter content: determined by potassium dichromate oxidation method. 3. Humic acid content: determined by sodium pyrophosphate-sodium hydroxide extraction-capacity method. 4. Nitrogen, phosphorus and potassium content: nitrogen content is determined by Kjeldahl method, phosphorus content is determined by molybdenum-antimony anti-colorimetric method, and potassium content is determined by flame photometry. 5. Ammonia emission: determined by dilute sulfuric acid absorption-acid-base titration method. 6. Hydrogen sulfide emission: determined by zinc acetate-sodium hydroxide solution absorption-methylene blue spectrophotometry.

[0024] The test results are recorded in the following table: Test item Example 1 Example 2 Example 3 Composting period / day 36 32 35 Nitrogen retention rate / % 81.9 83.7 81.4 Organic matter content / % 45.1 46.5 44.6 Humic acid content / % 17.6 19.2 17.3 Total nitrogen content / % 2.3 2.6 2.1 Total phosphorus content / % 1.7 1.9 1.6 Total potassium content / % 1.5 1.7 1.5 Ammonia emission amount (mg / kg) 84.5 82.4 84.2 Hydrogen sulfide emission amount (mg / kg) 64.1 61.8 63.5 By comparing and analyzing the related data in the table, it can be seen that the garden plant waste aerobic composting process provided by the application can effectively solve the problems of long composting period, low composting degree, serious nitrogen loss, high risk of secondary pollution and the like in the existing composting process, and realize efficient and environmentally friendly treatment and resource utilization of garden plant waste. Therefore, the garden plant waste aerobic composting process provided by the application has a wider market prospect and is more suitable for promotion.

[0025] In the description of the specification, reference to "one embodiment", "an example", "a specific example" or the like means that a particular feature, structure, material or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the application. The appearances of the phrases "in one embodiment", "an example", "a specific example" or the like in various places in the specification are not necessarily referring to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics can be combined in any suitable manner in one or more embodiments or examples.

[0026] The preferred embodiments of the application disclosed above are only to help explain the application. The preferred embodiments do not describe all the details of the application and limit the application to the specific embodiments described. Obviously, many modifications and variations can be made in light of the contents of the specification. The specification selects and specifically describes these embodiments in order to better explain the principles and practical application of the application, so that those skilled in the art can well understand and utilize the application. The application is limited only by the claims and their full scope and equivalents.

Claims

1. An aerobic composting process for garden plant waste, characterized in that: The following steps are involved: Step 1: Classify the garden plant waste to remove impurities therein, wash and dry the removed garden waste in turn, and then crush it into a mixed material with a particle size of ≤5 cm. The obtained mixed material is regulated and optimized and then stored for future use; Step 2: inoculating a composite microbial agent into the optimized mixture, wherein the composite microbial agent is composed of cellulose decomposing bacteria, lignin decomposing bacteria, nitrogen-fixing bacteria and yeast in a mass ratio of 1.5-2.5:2-3:1:1-1.5; Step 3: After inoculation with the compound microbial agent, the mixed materials are piled into a trapezoidal pile with a height of 1.5 to 2 meters, a width of 2 to 3 meters, and a length determined by the site; wherein, ventilation pipes are set inside the trapezoidal pile, the ventilation pipes are spaced 1 to 1.5 meters apart, and ventilation holes with a diameter of 0.5 to 1 cm are evenly distributed on the pipe wall; Step 4: Turn the compost every 2-3 days during the initial stage of composting, and monitor and adjust the oxygen concentration and pH value in real time; when the temperature of the trapezoidal pile is above 60°C and has been stable for 2-3 days, turn the compost every 5-7 days until the temperature of the trapezoidal pile drops below 40°C and does not rise again; Step 5: When the color of the trapezoidal compost material changes to dark brown, the texture is loose, and there is no foul smell, the compost material is sieved, dried and packaged in sequence to obtain aerobic compost of garden plant waste.

2. The aerobic composting process for garden plant waste according to claim 1, wherein: The control optimization process includes humidity control and carbon-nitrogen ratio control, and the humidity of the mixed material is controlled to be 50-60%, and the carbon-nitrogen ratio is controlled to be 25-30:

1.

3. The aerobic composting process for garden plant waste according to claim 1, wherein: The cellulose decomposing bacteria is selected from Trichoderma viride, and the lignin decomposing bacteria is selected from Phanerochaete chrysosporium.

4. The aerobic composting process for garden plant waste according to claim 1, wherein: The material of the ventilation tube in step 3 is any one of polyvinyl chloride and polyethylene, and the diameter of the tube is 5 to 10 cm.

5. The aerobic composting process for garden plant waste according to claim 2, wherein: When adjusting the carbon-nitrogen ratio, sawdust is used as the carbon source and chicken manure is used as the nitrogen source.

6. The aerobic composting process for garden plant waste according to claim 1, characterized in that: The screening process uses a screen with an aperture of 6 to 10 mm, the drying temperature is 50 to 60° C., and the moisture content of the dried compost material is ≤15%.

7. The aerobic composting process for garden plant waste according to claim 1, characterized in that: The specific operations for real-time monitoring of oxygen concentration are: when the oxygen concentration is ≤18%, increase the ventilation volume; when the oxygen concentration is ≥22%, reduce the ventilation volume.

8. The aerobic composting process for garden plant waste according to claim 1, characterized in that: The specific operation of real-time monitoring of pH value is: when the pH value is lower than 6.5, add lime; when the pH value is higher than 8.5, add superphosphate to keep the pH value within the range of 6.5 to 8.

5.

9. The aerobic composting process for garden plant waste according to claim 1, characterized in that: The criteria for determining maturity also include: seed germination index (GI) ≥ 90%, electrical conductivity (EC) ≤ 3.5mS / cm, ratio of ammonium nitrogen to nitrate nitrogen (NH4 + -N / NO3 ～ -N) is in the range of 0.2 to 0.

5.

10. The aerobic composting process for garden plant waste according to claim 1, characterized in that: The inoculation amount of the compound microbial agent is 0.5-1% of the total mass of the mixed material, and the compound microbial agent is evenly sprayed on the surface of the mixed material by atomization, and then mixed and stirred evenly.