Resource utilization method for synergistic composting of garden waste and kitchen treatment waste

Abstract

The invention discloses a resource utilization method for synergistic composting of garden waste and kitchen treatment waste. The resource utilization method comprises the following steps: S1, raw material treatment; s2, aerobic composting inoculant inoculation and material mixing; s3, manufacturing an aerobic composting pile body; s4, aerobic composting pile body condition control and aerobic composting fermentation; s5, preparing organic fertilizer and matrix nutrient soil. According to the resource utilization method, the low-value garden waste, the kitchen waste treatment waste residues and the waste water serve as raw materials, the organic fertilizer and the matrix nutrient soil are produced through an aerobic fermentation method, the comprehensive treatment cost of the low-value garden waste, the kitchen waste treatment waste residues and the waste water is low, the social and environmental benefits are good, and compost products are applied to agricultural production and have good economic benefits. The organic fertilizer can provide sufficient nutrients for crops, increase the soil organic matter content and the soil moisture retention capability, improve the soil structure and improve the flavor and quality of agricultural products, thereby realizing treatment of wastes with wastes and synergistic resource utilization of various organic wastes.

Description

Technical Field

[0001] The present application relates to the technical field of resource utilization and composting, and in particular to a resource utilization method of co-composting garden waste and kitchen waste. Background Art

[0002] At present, according to the differences in the material properties of garden waste, tree branches and trunks are of higher value and have many ways to be utilized as resources. They can be used as wood to produce high-value wood products. However, the small branches and leaves generated during the maintenance of urban municipal greening and the low-value garden waste collected by trimming park lawns have a moisture content of 50%-65%. With the rapid development of urbanization and the improvement of people's living standards, the amount of low-value waste generated has also increased significantly. Low-value garden waste has a high moisture content. If it is piled in the open air for a long time, it is easy to produce high-concentration organic wastewater such as leachate with the leaching of rainwater. If the pile is piled high, it is very easy to cause anaerobic fermentation to produce combustible gases such as biogas, and the temperature will rise, which will cause spontaneous combustion. If low-value garden waste is not properly handled, there will be great safety and environmental risks.

[0003] The three-phase centrifuge solid residue produced after sorting, pulping, sand removal and oil extraction of food waste is rich in highly nutritious organic matter, with a moisture content of 75%-85%. This part of the material contains more fruit and vegetable fiber, starch, fat, and protein. The three-phase centrifuge solid residue material enters the anaerobic fermentation system. The degradation efficiency of the solid residue material is low and the residence time is long, which will form more biogas residue. The protein materials with more nitrogen are easy to cause the total nitrogen and ammonia nitrogen concentration of the biogas slurry to increase after decomposition. When the biogas slurry is used as sewage treatment, the C / N is relatively low, and additional sewage treatment is required to supplement the carbon source, which increases the cost of sewage treatment. The three-phase centrifuge solid residue generated by some food waste treatment projects is directly sent to the domestic waste incineration power plant for incineration and disposal, without resource utilization. While the anaerobic fermentation of food waste produces biogas, it also produces a large amount of biogas residue and biogas slurry. The treatment of biogas residue and biogas slurry has always been a problem that plagues food waste treatment companies.

[0004] At present, low-value garden waste is mainly treated by aerobic fermentation and composting. The content of nutrients such as N, P, and K contained in the composted materials of single low-value garden waste is low, and its compost products are mainly sold as low-value products such as substrate soil and nutrient soil for landscaping. The resource products have low value, limited application scope, and poor product sales, which seriously restricts the sustainable and stable operation of low-value garden waste composting projects. The restaurant biogas residue is mainly dehydrated and then sent to the waste incineration power plant for incineration and disposal, and the biogas liquid is treated by sewage treatment, which greatly increases the treatment cost of restaurant biogas residue and biogas liquid.

[0005] Therefore, there is an urgent need for a resource utilization method that uses low-value garden waste and food waste to treat waste residues and wastewater through coordinated aerobic composting. Summary of the invention

[0006] The purpose of this application is to provide a resource utilization method for the coordinated composting of garden waste and kitchen waste, so as to solve the problem that low-value garden waste is currently mainly treated by aerobic fermentation composting, and the materials after single low-value garden waste composting contain low content of nutrients such as N, P, and K. Its compost products are mainly sold as low-value products such as substrate soil and nutrient soil for landscaping. The resource products have low value, limited application scope, and poor product sales, which seriously restricts the sustainable and stable operation of low-value garden waste composting projects. The kitchen sludge is mainly dehydrated and then sent to the garbage incineration power plant for incineration disposal, and the biogas liquid is treated by sewage treatment, which greatly increases the treatment cost of kitchen sludge and biogas liquid.

[0007] The resource utilization method of the garden waste and the kitchen waste co-composting provided in the present application adopts the following technical scheme: The resource utilization method of garden waste and kitchen waste by co-composting comprises the following steps: S1. Raw material processing: ① Low-value garden waste raw material processing: pre-process the collected low-value garden waste, crush and pulverize the low-value garden waste; ② Food waste residue and wastewater raw material processing: sort and remove impurities, remove sand, heat and cook, and extract oil from the three-phase centrifuge to separate the three-phase solid residue from the three-phase centrifuge, the biogas residue and biogas liquid discharged from the anaerobic digestion tank of the food waste, and the anaerobic sludge and aerobic sludge generated after the biogas liquid is subjected to two-stage A / O biochemical treatment; S2. Inoculation and mixing of aerobic composting agents: Add and inoculate aerobic composting agents to the crushed and pulverized low-value garden waste at a ratio of 0.1‰-0.5‰. The low-value garden waste after inoculation of the agents is mixed with restaurant kitchen waste residue and wastewater at a ratio of 1-2:2-3:0-1, and the moisture content of the pile after mixing is ensured to be 60%-65%; S3. Preparation of aerobic compost pile: Start the compost turning machine to spread and pile the materials inoculated with aerobic composting bacteria into a compost pile with a width of ≥4.0m, a height of 1.5m-2.5m, and a length of ≥5m; S4. Aerobic composting pile condition control and aerobic composting fermentation: ① Cover the surface of the aerobic composting pile with a layer of PTFE composting film; ② With the rapid growth and reproduction of microorganisms in the aerobic composting pile, after 2-3 days of fermentation, the activity of aerobic microorganisms is enhanced, and the metabolism of microorganisms is more vigorous. After the temperature of the aerobic composting pile rises to 55-70℃, the oxygen consumption and water loss between the materials in the composting pile are fast, and it is necessary to turn the pile and replenish water in time. By spraying kitchen biogas wastewater as water supplement, not only can the water lost by the composting pile be replenished appropriately, but the fertilizer efficiency and nutritional indicators contained in the biogas slurry can also add certain nutrients to the composting pile; S5. Preparation of organic fertilizer and matrix nutrient soil: After 20 days of composting fermentation, no more water will be added to the pile. The entire aerobic composting fermentation and decomposition cycle is expected to last 25 days to 35 days. After decomposition, the compost material needs to be aged for 12 days to 20 days. The prepared material can be used as organic fertilizer and matrix nutrient soil.

[0008] Furthermore, in step S1, the particle size of the crushed low-value garden waste is 2-5 cm, and the moisture content of the crushed low-value garden waste is 40%-65%.

[0009] Furthermore, in step S1, the three-phase solid residue of kitchen waste must meet the following relevant technical index requirements: organic matter content is 60%-80%, moisture is 75%-85%, total nutrients are 10%-20%, pH value is 3.5-6.5, calcium content is 300mg / kg-400mg / kg, mercury content is 0mg / kg-0.01mg / kg, and arsenic, cadmium, chromium and lead contents are all 0mg / kg-0.02mg / kg.

[0010] Furthermore, food digestate, anaerobic and aerobic sludge must meet the following relevant technical index requirements: organic matter content of 18%-25%, moisture of 60%-85%, total nutrients of 5%-8%, pH value of 7.5-9.0, calcium content of 200mg / kg-400mg / kg, mercury content of 0mg / kg-0.01mg / kg, arsenic, cadmium, chromium and lead content of 0mg / kg-0.02mg / kg.

[0011] Furthermore, the kitchen biogas slurry must meet the following relevant technical index requirements: organic matter content of 5g / L-10g / L, moisture of 96%-98%, total nutrients of 15.0g / L-60g / L, pH value of 7.0-8.5, calcium content of 200mg / kg-300mg / kg, mercury content of 0mg / kg-0.01mg / kg, arsenic, cadmium, chromium and lead content of 0mg / kg-0.02mg / kg.

[0012] Further, in step S2, the aerobic composting agent is mainly composed of beneficial strains with specific functions such as Bacillus subtilis, Bacillus laterosporus, yeast, actinomycetes, lactic acid bacteria, photosynthetic bacteria, Trichoderma, Aspergillus, Streptomyces, etc. and related enzymes, and the effective live bacteria count is above 12 billion CFU·g-1.

[0013] Furthermore, during the entire composting process, the moisture content and temperature of the compost pile must be continuously monitored every day.

[0014] Furthermore, within 10d-12d of composting fermentation, when the moisture content of the material is less than 40%, the moisture of the pile should be replenished by timely spraying anaerobic food digester wastewater until the moisture content is 50%-60%; the pile should be turned every 3d-5d, and the whole pile should be fully turned and mixed.

[0015] Furthermore, during the entire composting process, it is necessary to ensure that the temperature of the pile is maintained between 65℃ and 70℃ for 5-7 consecutive days; when the temperature of the pile is greater than 70℃, the temperature of the pile can be lowered by continuously turning the pile or spraying anaerobic food digester wastewater.

[0016] Compared with the prior art, the beneficial effects of this application are: The resource utilization method of the present application uses low-value garden waste, kitchen waste treatment waste residue, and wastewater as raw materials, and produces organic fertilizer and substrate nutrient soil through aerobic fermentation. The comprehensive treatment cost of low-value garden waste and kitchen waste treatment waste residue and wastewater is low, and the social and environmental benefits are good. Its compost products are applied to agricultural production, which can provide sufficient nutrients for crops, increase the organic matter content of soil and the water retention capacity of soil, and improve the soil structure and the flavor and quality of agricultural products, thereby achieving waste treatment with waste, and the coordinated resource utilization of multiple organic wastes. At the same time, its aerobic composting process is simple, and the fertilizer efficiency index and added value of the compost product are improved by mixing and compounding different materials for fermentation and composting.

[0017] In addition, by adjusting the mixing ratio of different types of materials, the purpose of improving the fertilizer efficiency of aerobic fermentation compost products of low-value garden waste can be achieved, the market value of its resource products can be increased, the application scope of resource products and product sales can be broadened, and it can also provide new resource utilization paths and treatment solutions for food waste treatment waste residues (including three-phase centrifuge solid residues, anaerobic sludge residues, anaerobic and aerobic sludge of biogas slurry) and wastewater (anaerobic biogas slurry), reduce the cost of harmless treatment of waste residues and wastewater in food waste treatment plants, and save supplementary water in the composting and fermentation process of low-value garden waste. DETAILED DESCRIPTION

[0018] The present application is described in further detail below.

[0019] The present application embodiment discloses a resource utilization method of garden waste and kitchen waste by co-composting, comprising the following steps: S1. Raw material processing: ① Processing of low-value garden waste raw materials: pre-treat the collected low-value garden waste, crush and pulverize it; specifically, the particle size of the crushed low-value garden waste is 2-5cm, and the moisture content of the crushed low-value garden waste is 40%-65%, which can effectively improve the subsequent resource utilization.

[0020] ② Treatment of restaurant waste residue and wastewater raw materials: The collected restaurant waste is sorted, desanded, heated and cooked, and oil extracted by a three-phase centrifuge to produce three-phase solid residue separated by a three-phase centrifuge, and the sludge and biogas discharged from the anaerobic digester of restaurant waste, as well as the anaerobic sludge and aerobic sludge produced after the two-stage A / O biochemical treatment of the biogas sludge.

[0021] Specifically, in the above-mentioned kitchen waste treatment steps, the generated three-phase solid residue of kitchen waste must meet the following relevant technical index requirements: organic matter content is 60%-80%, moisture is 75%-85%, total nutrients are 10%-20%, pH value is 3.5-6.5, calcium content is 300mg / kg-400mg / kg, mercury content is 0mg / kg-0.01mg / kg, arsenic, cadmium, chromium, lead content are all 0mg / kg-0.02mg / kg.

[0022] At the same time, the generated food digestate, anaerobic and aerobic sludge must meet the following relevant technical indicators: organic matter content is 18%-25%, moisture is 60%-85%, total nutrients are 5%-8%, pH value is 7.5-9.0, calcium content is 200mg / kg-400mg / kg, mercury content is 0mg / kg-0.01mg / kg, arsenic, cadmium, chromium and lead content are all 0mg / kg-0.02mg / kg.

[0023] In addition, the produced kitchen biogas liquid must meet the following relevant technical index requirements: organic matter content of 5g / L-10g / L, moisture of 96%-98%, total nutrients of 15.0g / L-60g / L, pH value of 7.0-8.5, calcium content of 200mg / kg-300mg / kg, mercury content of 0mg / kg-0.01mg / kg, arsenic, cadmium, chromium and lead content of 0mg / kg-0.02mg / kg.

[0024] More specifically, the technical indicators of the above-mentioned kitchen waste residue and wastewater raw materials are shown in Table 1: S2. Inoculation and mixing of aerobic composting agent: add and inoculate aerobic composting agent to the crushed and pulverized low-value garden waste at a ratio of 0.1‰-0.5‰, and mix the inoculated low-value garden waste with restaurant kitchen waste residue and wastewater at a ratio of 1-2:2-3:0-1 to turn the pile, ensuring that the moisture content of the pile after mixing is 60%-65%; specifically, in step S2, the aerobic composting agent is mainly composed of beneficial strains with specific functions such as Bacillus subtilis, Bacillus laterosporus, yeast, actinomycetes, lactic acid bacteria, photosynthetic bacteria, Trichoderma, Aspergillus, Streptomyces, etc. and related enzymes, and the effective live bacteria count is above 12 billion CFU·g-1.

[0025] S3. Preparation of aerobic compost pile: Start the compost turning machine to spread and pile the materials inoculated with aerobic composting bacteria into a compost pile with a width of ≥4.0m, a height of 1.5m-2.5m and a length of ≥5m.

[0026] S4. Aerobic composting pile condition control and aerobic composting fermentation: ① Cover the surface of the aerobic compost pile with a layer of PTFE compost membrane. The PTFE membrane is waterproof and breathable, unidirectional permeable, heat-insulating, high-strength and durable, and has good chemical stability. Its pore size is at the nanometer level, and it has the characteristics of selective permeability to gases. Specifically, the carbon dioxide and water vapor generated during the fermentation process can diffuse out from the microporous structure of the membrane, while external air pollutants and odors are difficult to enter the membrane. At the same time, the odor, VOC, bacteria and dust generated by the fermentation can be blocked in the membrane for continued decomposition, reducing pollution to the surrounding environment, and external rainwater will not penetrate into the compost pile, keeping the pile dry and breathable.

[0027] At the same time, it can block the loss of heat inside the pile to a certain extent, so that the heat generated during the composting process can be better retained inside the pile, maintaining the high temperature environment of the pile, which is conducive to accelerating the decomposition and composting of organic waste; it also plays a sterilization role, killing pathogens, grass seeds, parasites, etc. in the composting materials, thereby improving the harmlessness of the compost.

[0028] ② With the rapid growth and reproduction of microorganisms in the aerobic compost pile, after 2-3 days of fermentation, the activity of aerobic microorganisms is enhanced, and the metabolism of microorganisms is more vigorous. After the temperature of the aerobic compost pile rises to 55℃-70℃, the oxygen between the materials in the compost pile is consumed quickly and the water is lost quickly. It is necessary to turn the compost pile and replenish water in time. By spraying kitchen biogas wastewater as water supplement, not only can the water lost by the compost pile be replenished appropriately, but the fertilizer and nutritional indicators contained in the biogas slurry can also add certain nutrients to the compost pile.

[0029] Optimized, during the entire composting process, the moisture content and temperature of the compost pile need to be continuously monitored every day. Specifically, within 10-12 days of composting, when the moisture content of the material is less than 40%, the moisture of the pile should be replenished by spraying anaerobic food digester wastewater in time until the moisture content is 50%-60%; the pile should be turned every 3-5 days, and it is advisable to turn the whole pile fully and mix it evenly.

[0030] At the same time, during the entire composting process, it is necessary to ensure that the temperature of the pile is maintained between 65℃ and 70℃ for 5 consecutive days. When the temperature of the pile is greater than 70℃, the temperature of the pile can be lowered by continuously turning the pile or spraying anaerobic digester wastewater.

[0031] S5. Preparation of organic fertilizer and matrix nutrient soil: After 20 days of composting fermentation, no more water will be added to the pile. The entire aerobic composting fermentation and decomposition cycle is expected to last 25 days to 35 days. After decomposition, the compost material needs to be aged for 12 days to 20 days. The prepared material can be used as organic fertilizer and matrix nutrient soil.

[0032] Specifically, the technical indicators of the organic fertilizer and substrate nutrient soil prepared above are shown in Table 2: Therefore, in summary, the resource utilization method of the present application uses low-value garden waste, kitchen waste treatment waste residue, and wastewater as raw materials, and produces organic fertilizer and matrix nutrient soil through aerobic fermentation method. The comprehensive treatment cost of low-value garden waste and kitchen waste treatment waste residue and wastewater is low, and the social and environmental benefits are good. Its compost products are applied to agricultural production, which can provide sufficient nutrients for crops, increase soil organic matter content and soil moisture retention capacity, and improve soil structure and improve the flavor and quality of agricultural products, thereby achieving waste treatment with waste, and synergistic resource utilization of multiple organic wastes. At the same time, its aerobic composting process is simple, and the fertilizer efficiency index and added value of compost products are improved by mixing and compounding different materials for fermentation and composting.

[0033] In addition, by adjusting the mixing ratio of different types of materials, the purpose of improving the fertilizer efficiency of aerobic fermentation compost products of low-value garden waste can be achieved, the market value of its resource products can be increased, the application scope of resource products and product sales can be broadened, and it can also provide new resource utilization paths and treatment solutions for food waste treatment waste residues (including three-phase centrifuge solid residues, anaerobic sludge residues, anaerobic and aerobic sludge of biogas slurry) and wastewater (anaerobic biogas slurry), reduce the cost of harmless treatment of waste residues and wastewater in food waste treatment plants, and save supplementary water in the composting and fermentation process of low-value garden waste.

[0034] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the specification of the present invention, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A resource utilization method of garden waste and kitchen waste by synergistic composting, characterized in that: The following steps are involved: S1. Raw material processing: ① Low-value garden waste raw material processing: pre-process the collected low-value garden waste, crush and pulverize the low-value garden waste; ② Food waste residue and wastewater raw material processing: sort and remove impurities, remove sand, heat and cook, and extract oil from the three-phase centrifuge to separate the three-phase solid residue from the three-phase centrifuge, the biogas residue and biogas liquid discharged from the anaerobic digestion tank of the food waste, and the anaerobic sludge and aerobic sludge generated after the biogas liquid is subjected to two-stage A / O biochemical treatment; S2. Inoculation and mixing of aerobic composting agents: Add and inoculate aerobic composting agents to the crushed and pulverized low-value garden waste at a ratio of 0.1‰-0.5‰. The low-value garden waste after inoculation of the agents is mixed with restaurant kitchen waste residue and wastewater at a ratio of 1-2:2-3:0-1, and the moisture content of the pile after mixing is ensured to be 60%-65%; S3. Preparation of aerobic compost pile: Start the compost turning machine to spread and pile the materials inoculated with aerobic composting bacteria into a compost pile with a width of ≥4.0m, a height of 1.5m-2.5m, and a length of ≥5m; S4. Aerobic composting pile condition control and aerobic composting fermentation: ① Cover the surface of the aerobic composting pile with a layer of PTFE composting film; ② With the rapid growth and reproduction of microorganisms in the aerobic composting pile, after 2-3 days of fermentation, the activity of aerobic microorganisms is enhanced, and the metabolism of microorganisms is more vigorous. After the temperature of the aerobic composting pile rises to 55-70℃, the oxygen consumption and water loss between the materials in the composting pile are fast, and it is necessary to turn the pile and replenish water in time. By spraying kitchen biogas wastewater as water supplement, not only can the water lost by the composting pile be replenished appropriately, but the fertilizer efficiency and nutritional indicators contained in the biogas slurry can also add certain nutrients to the composting pile; S5. Preparation of organic fertilizer and matrix nutrient soil: After 20 days of composting fermentation, no more water will be added to the pile. The entire aerobic composting fermentation and decomposition cycle is expected to last 25 days to 35 days. After decomposition, the compost material needs to be aged for 12 days to 20 days. The prepared material can be used as organic fertilizer and matrix nutrient soil.

2. The resource utilization method of garden waste and kitchen waste by synergistic composting according to claim 1, characterized in that: In step S1, the particle size of the crushed low-value garden waste is 2-5 cm, and the moisture content of the crushed low-value garden waste is 40%-65%.

3. The resource utilization method of garden waste and kitchen waste by synergistic composting according to claim 1, characterized in that: In step S1, the three-phase solid residue of kitchen waste must meet the following relevant technical index requirements: organic matter content is 60%-80%, moisture is 75%-85%, total nutrients are 10%-20%, pH value is 3.5-6.5, calcium content is 300mg / kg-400mg / kg, mercury content is 0mg / kg-0.01mg / kg, and arsenic, cadmium, chromium and lead content are all 0mg / kg-0.02mg / kg.

4. The resource utilization method of garden waste and kitchen waste by synergistic composting according to claim 3 is characterized in that: Food digestate, anaerobic and aerobic sludge must meet the following relevant technical indicators: organic matter content is 18%-25%, moisture is 60%-85%, total nutrients are 5%-8%, pH value is 7.5-9.0, calcium content is 200mg / kg-400mg / kg, mercury content is 0mg / kg-0.01mg / kg, arsenic, cadmium, chromium and lead content are all 0mg / kg-0.02mg / kg.

5. The resource utilization method of garden waste and kitchen waste by synergistic composting according to claim 4, characterized in that: Kitchen biogas slurry must meet the following relevant technical indicators: organic matter content of 5g / L-10g / L, moisture of 96%-98%, total nutrients of 15.0g / L-60g / L, pH value of 7.0-8.5, calcium content of 200mg / kg-300mg / kg, mercury content of 0mg / kg-0.01mg / kg, arsenic, cadmium, chromium and lead content of 0mg / kg-0.02mg / kg.

6. The resource utilization method of garden waste and kitchen waste by synergistic composting according to claim 1, characterized in that: In step S2, the aerobic composting agent is mainly composed of beneficial strains with specific functions such as Bacillus subtilis, Bacillus laterosporus, yeast, actinomycetes, lactic acid bacteria, photosynthetic bacteria, Trichoderma, Aspergillus, Streptomyces, etc. and related enzymes, and the effective live bacteria count is above 12 billion CFU·g-1.

7. The resource utilization method of garden waste and kitchen waste by synergistic composting according to claim 1, characterized in that: During the entire composting process, the moisture content and temperature of the compost pile must be monitored continuously every day.

8. The resource utilization method of garden waste and kitchen waste by synergistic composting according to claim 7, characterized in that: During the 10-12 days of composting fermentation, when the moisture content of the material is less than 40%, the moisture of the pile should be replenished by timely spraying anaerobic food digester wastewater until the moisture content reaches 50%-60%. The pile should be turned every 3-5 days to ensure that the entire pile is fully turned and mixed.

9. The resource utilization method of garden waste and kitchen waste by synergistic composting according to claim 7, characterized in that: During the entire composting process, it is necessary to ensure that the temperature of the pile is maintained between 65℃ and 70℃ for 5-7 consecutive days; when the temperature of the pile is greater than 70℃, the temperature of the pile can be lowered by continuously turning the pile or spraying anaerobic digestate wastewater.

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