Method for composting manure of hermetia illucens by using duckweed and biochar

Abstract

The invention relates to a method for composting black soldier fly feces by using duckweed and charcoal, which comprises the following steps: collecting black soldier fly feces and biological wastes, weighing the black soldier fly feces and biological wastes, and spraying a microbial complex microbial inoculant which is bacillus subtilis and bacillus stearothermophilus. A combination of nitrosomonas, nitrobacter, white-rot fungi and streptomyces; obtaining a primary compost; laying biochar on the surface of the preliminary compost, and then laying duckweed on the outer surface of the biochar layer; stacking in sunlight at normal temperature; and after the temperature of the compost body is reduced to 50 DEG C or below, turning the outer charcoal and the duckweed into the compost, and covering the surface of the compost body with the charcoal after turning to complete the composting. The adopted duckweed can utilize nitrogen discharged by compost, and the biochar can adsorb the nitrogen discharged by the compost, so that the duckweed can better utilize the nitrogen discharged by the compost, the nitrogen in the compost is immobilized and converted, the nitrogen loss of the compost is reduced, and the foul smell of a compost body is reduced.

Description

Technical Field

[0001] The invention belongs to the field of agriculture and relates to a composting method, in particular to a method for composting black soldier fly feces by utilizing duckweed and biochar. Background Art

[0002] Black soldier fly (scientific name: Hermetia illucens) excrement, also known as black soldier fly prepupa excrement or black soldier fly feces, is the solid waste discharged by black soldier fly larvae after digesting organic waste. This organic fertilizer has received increasing attention in the fields of agriculture and horticulture due to its unique properties and wide range of uses. Black soldier fly excrement is rich in a variety of essential nutrients for plants, such as nitrogen, phosphorus, and potassium. It also contains secondary elements such as calcium, magnesium, and sulfur, as well as trace elements such as iron, zinc, and copper. It can improve soil structure and increase the soil's ability to retain water and fertilizer. It also contains a variety of beneficial microorganisms, which help inhibit the growth of harmful microorganisms in the soil and promote healthy plant growth.

[0003] Black soldier flies may produce strong irritating odors, such as ammonia and hydrogen sulfide, when processing organic waste. These odors not only reduce the quality of the environment and affect the quality of life and health of surrounding residents, including causing respiratory irritation, nervous system effects and mental health problems, but may also cause damage to the ecological environment, such as polluting water and soil, attracting pests, etc. At the same time, the odor problem may also hinder the promotion and application of black soldier fly technology.

[0004] Duckweed is a small aquatic plant belonging to the family Lemnaeidae. They are widely distributed in still or slow-flowing waters around the world, such as ponds, lakes, and rivers. The characteristic of duckweed is that its stems and leaves float on the water surface, while its roots hang directly in the water without contacting the bottom mud. Duckweed can effectively absorb nutrients such as nitrogen and phosphorus in the water, which helps to purify water quality and reduce eutrophication caused by excessive algae growth.

[0005] Biochar is a carbonaceous material made by pyrolysis (heating organic matter under oxygen-deficient conditions), usually made from biomass raw materials such as agricultural waste and wood residues. Biochar has been widely used in agriculture, environmental remediation and other fields due to its unique physical and chemical properties. The porous structure and rich functional groups of biochar can adsorb and fix free nitrogen, reducing the loss and volatilization of nitrogen. Summary of the invention

[0006] In view of the above technical problems in the prior art, the present invention provides a method for composting black soldier fly feces using duckweed and biochar. The method for composting black soldier fly feces using duckweed and biochar is intended to solve the technical problem of the prior art that it is difficult to treat black soldier fly feces with strong ammonia smell.

[0007] The present invention provides a method for composting black soldier fly feces using duckweed and biochar, comprising the following steps:

[0008] 1) collecting black soldier fly feces and biological waste, wherein the biological waste is any one of sawdust or dead branches and leaves, or a mixture of the two in any proportion;

[0009] 2) weighing black soldier fly feces and biological waste, mixing them, making the carbon-nitrogen ratio in the mixture (20-35):1, and then spraying 1%-3% of the mass of the mixed material with a microbial composite agent, wherein the microbial composite agent is a combination of Bacillus subtilis, Bacillus stearothermophilus, Nitrosomonas, Nitrobacter, white rot fungi, and Streptomyces; adding water to control the moisture content to 55-60%, and obtaining preliminary compost;

[0010] 3) Lay 1-5 cm thick biochar on the surface of the preliminary compost, and then lay 1-3 cm thick duckweed on the outer surface of the biochar layer; pile at room temperature under sunlight;

[0011] 4) After the temperature of the pile drops below 50°C, turn the biochar and duckweed outside into the compost. After turning the pile, cover the surface of the pile with 0.5-3cm thick biochar, and the composting is completed.

[0012] Specifically, in the microbial composite agent, the quantity ratio of Bacillus subtilis, Bacillus stearothermophilus, Nitrosomonas, Nitrobacter, white rot fungi, and Streptomyces is 1:1:1:1:1:1:1.

[0013] Compared with the prior art, the present invention has a positive and obvious technical effect. The duckweed used in the present invention can utilize the nitrogen discharged from the compost, and the biochar can absorb the nitrogen discharged from the compost, so that the duckweed can better utilize the nitrogen in the compost. The combination of the two can more effectively absorb, fix and convert the nitrogen in the compost, reduce the loss of nitrogen in the compost, and reduce the odor of the compost body. DETAILED DESCRIPTION

[0014] Example 1

[0015] The present invention provides a method for composting black soldier fly feces using duckweed and biochar, comprising the following steps:

[0016] 1) collecting black soldier fly feces and biological waste, wherein the biological waste is any one of sawdust or dead branches and leaves, or a mixture of the two in any proportion;

[0017] 2) weighing black soldier fly feces and biological waste, mixing them so that the carbon-nitrogen ratio in the mixture is 25:1, and then spraying 3% of the mass of the mixed material with a microbial composite agent, wherein the microbial composite agent is a combination of Bacillus subtilis, Bacillus stearothermophilus, Nitrosomonas, Nitrobacter, white rot fungi, and Streptomyces; adding water to control the moisture content to 55%, and obtaining preliminary compost;

[0018] 3) Lay a 5 cm thick layer of biochar on the surface of the preliminary compost, and then lay a 3 cm thick layer of duckweed on the outer surface of the biochar layer; stack at room temperature under sunlight;

[0019] 4) After the temperature of the pile drops below 50°C, turn the biochar and duckweed outside into the compost. After turning the pile, cover the surface of the pile with 3 cm thick biochar, and the composting is completed.

[0020] Specifically, in the microbial composite agent, the quantity ratio of Bacillus subtilis, Bacillus stearothermophilus, Nitrosomonas, Nitrobacter, white rot fungi, and Streptomyces is 1:1:1:1:1:1:1.

[0022] Control group 1:

[0023] The present invention provides a method for composting black soldier fly feces by using duckweed, comprising the following steps:

[0024] 1) collecting black soldier fly feces and biological waste, wherein the biological waste is any one of sawdust or dead branches and leaves, or a mixture of the two in any proportion;

[0025] 2) weighing black soldier fly feces and biological waste, mixing them so that the carbon-nitrogen ratio in the mixture is 25:1, and then spraying 3% of the mass of the mixed material with a microbial composite agent, wherein the microbial composite agent is a combination of Bacillus subtilis, Bacillus stearothermophilus, Nitrosomonas, Nitrobacter, white rot fungi, and Streptomyces; adding water to control the moisture content to 55%, and obtaining preliminary compost;

[0026] 3) Lay 3cm thick duckweed on the surface of the preliminary compost and pile it at room temperature under sunlight;

[0027] 4) When the temperature of the pile drops below 50°C, turn the duckweed outside into the compost and the composting is completed.

[0028] Specifically, in the microbial composite agent, the quantity ratio of Bacillus subtilis, Bacillus stearothermophilus, Nitrosomonas, Nitrobacter, white rot fungi, and Streptomyces is 1:1:1:1:1:1:1.

[0029] Control group 2:

[0030] The present invention provides a method for composting black soldier fly excrement using biochar, comprising the following steps: 1) collecting black soldier fly excrement and biological waste, wherein the biological waste is any one of sawdust or dead branches and leaves, or a mixture of the two in any proportion;

[0031] 2) weighing black soldier fly feces and biological waste, mixing them so that the carbon-nitrogen ratio in the mixture is 25:1, and then spraying 3% of the mass of the mixed material with a microbial composite agent, wherein the microbial composite agent is a combination of Bacillus subtilis, Bacillus stearothermophilus, Nitrosomonas, Nitrobacter, white rot fungi, and Streptomyces; adding water to control the moisture content to 55%, and obtaining preliminary compost;

[0032] 3) Lay 5 cm thick biochar on the surface of the preliminary compost and pile it at room temperature under sunlight;

[0033] 4) After the temperature of the pile drops below 50°C, turn the biochar outside into the compost. After turning the pile, cover the surface of the pile with 3 cm thick biochar, and the composting is completed.

[0034] Specifically, in the microbial composite agent, the quantity ratio of Bacillus subtilis, Bacillus stearothermophilus, Nitrosomonas, Nitrobacter, white rot fungi, and Streptomyces is 1:1:1:1:1:1:1.

[0035] During the composting process, organic matter degrades and produces greenhouse gases such as carbon dioxide and ammonia. The present invention reduces the volatilization of gases such as ammonia and carbon dioxide, so total nitrogen and organic matter are selected as measurement indicators.

[0036] Total nitrogen % (mass percentage) Organic matter% (mass percentage) Comparison 1 2.1 29.6 Comparison 2 2.8 34.5 Experimental Group 5.5 57.2

[0037] The present invention lays biochar on the surface of the pile, and then lays duckweed. Duckweed can photosynthesize by absorbing carbon dioxide emitted by composting, and can directly absorb ammonium ions and use them to synthesize proteins and other nitrogen-containing compounds, thereby supporting its own growth and development. The biochar layer plays a buffering role, can better absorb, store and release various greenhouse gases generated by composting, and at the same time absorb, store and release oxygen generated by duckweed, and play the role of a gas exchange channel. In this way, the emission of greenhouse gases such as carbon dioxide and ammonia can be reduced.

[0038] The temperature of the compost in the early stage of the present invention is high, and greenhouse gases such as carbon dioxide and ammonia are easy to volatilize. The combination of biochar + duckweed can greatly absorb various greenhouse gases emitted by the compost, reduce the high-temperature volatilization of ammonia, etc., and at the same time, the adsorbed ammonia is partially used by the duckweed, and it also plays a role in nitrogen fixation. Subsequently, the duckweed and biochar containing a large amount of nitrogen on the outer surface of the compost are turned into the inside of the compost, and the nitrogen is refluxed into the compost. At the same time, the nitrogen-containing biochar also provides carriers and nutrients for the large-scale reproduction of fungi in the subsequent mature stage of the compost. A layer of biochar covering the outside of the compost is for better heat preservation and adsorption of other low-temperature volatile gases.

Claims

1. A method for composting black soldier fly feces using duckweed and biochar, characterized in that The steps include: 1) collecting black soldier fly feces and biological waste, wherein the biological waste is any one of sawdust or dead branches and leaves, or a mixture of the two in any proportion; 2) weighing black soldier fly feces and biological waste, mixing them, making the carbon-nitrogen ratio in the mixture (20-35):1, and then spraying 1%-3% of the mass of the mixed material with a microbial composite agent, wherein the microbial composite agent is a combination of Bacillus subtilis, Bacillus stearothermophilus, Nitrosomonas, Nitrobacter, white rot fungi, and Streptomyces; adding water to control the moisture content to 55-60%, and obtaining preliminary compost; 3) Lay 1-5 cm thick biochar on the surface of the preliminary compost, and then lay 1-3 cm thick duckweed on the outer surface of the biochar layer; pile at room temperature under sunlight; 4) After the temperature of the pile drops below 50°C, turn the biochar and duckweed outside into the compost. After turning the pile, cover the surface of the pile with 0.5-3cm thick biochar, and the composting is completed.

2. The method for composting black soldier fly feces using duckweed and biochar according to claim 1, characterized in that: In the microbial composite agent, the quantity ratio of Bacillus subtilis, Bacillus stearothermophilus, Nitrosomonas, Nitrobacter, white rot fungi and Streptomyces is 1:1:1:1:1:1:1.