Method for treating medicine residues by using protaetia brevitarsis larvae

Abstract

The invention relates to the technical field of biodegradation, in particular to a method for treating medicine residues by using protaetia brevitarsis larvae, which comprises the following steps: step 1, crushing fresh medicine residues with the water content of 75-85%, inoculating a compound microbial agent (containing cellulose degrading bacteria, lignin degrading bacteria and saccharomycetes), and carrying out aerobic fermentation at 40-50 DEG C for 7-15 days to obtain fermentation liquid; a pretreated medicine residue matrix is obtained; the inoculum size of the compound microbial agent is 0.5%-2% of the weight of the medicine residues. The vigorous feeding and digestion capabilities of the protaetia brevitarsis larvae are utilized, the medicine residue treatment period is shortened to 35-45 days and is remarkably higher than that of traditional compost, rapid reduction of waste is achieved, and high efficiency and reduction are achieved.

Description

Technical Field

[0001] This invention relates to the field of biodegradation technology, and in particular to a method for treating medicinal residues using white-spotted flower beetle larvae. Background Technology

[0002] The production of traditional Chinese medicine (TCM) generates a large amount of residue, primarily composed of plant cellulose, hemicellulose, lignin, and residual starch, protein, and other organic matter. Currently, the main methods for treating this residue include landfilling, incineration, and use as compost. These traditional methods have the following drawbacks:

[0003] Landfilling: It occupies a large amount of land resources and easily produces leachate and biogas, causing secondary pollution.

[0004] Incineration: High energy consumption, large investment and operating costs, and may produce harmful gases, which does not meet the requirements of green environmental protection.

[0005] Traditional composting: It takes a long time (usually 2-3 months), is inefficient, easily produces odors and attracts flies and mosquitoes, and has low added value.

[0006] Studies have found that the larvae of the white-spotted flower beetle are saprophytic insects with strong vitality and a wide range of diets, capable of efficiently decomposing organic matter such as cellulose. While there are reports of using insects such as black soldier flies and mealworms to treat kitchen waste, there are no publicly reported methods specifically targeting the complex composition and high fiber content of traditional Chinese medicine residues, and systematically applying the larvae of the white-spotted flower beetle to its harmless, reduced-volume, and resource-oriented treatment. Summary of the Invention

[0007] The purpose of this invention is to overcome the shortcomings of the prior art and provide a method for treating medicinal residues based on the biotransformation of white-spotted beetle larvae, which has a simple process, high processing efficiency, low cost, and can realize the high-value utilization of medicinal residues.

[0008] To achieve the above objectives, the present invention provides the following technical solution: a method for treating pesticide residue using white-spotted flower beetle larvae, comprising the following steps:

[0009] Step 1: After crushing the fresh medicinal residue with a moisture content of 75%-85%, inoculate it with a compound microbial agent (containing cellulose-degrading bacteria, lignin-degrading bacteria and yeast), and ferment it aerobically at 40-50℃ for 7-15 days to obtain a pretreated medicinal residue matrix; the inoculation amount of the compound microbial agent is 0.5%-2% of the weight of the medicinal residue.

[0010] Step Two: Place the pretreated drug residue substrate obtained in Step One on a multi-layer breeding rack, with each layer of substrate being 15-25cm thick. First, inoculate with 2nd instar white-spotted flower beetle larvae at a density of 1.0-1.5 kg / m². After 5-7 days, evenly supplement the surface layer of the same substrate with 1st instar white-spotted flower beetle larvae at a density of 0.5-0.8 kg / m².

[0011] Step 3: Control the breeding environment temperature to 25-30℃ and humidity to 60%-70%. Turn the feed bed over every 5 days, and dynamically replenish the fresh pretreated drug residue substrate prepared in Step 1 from the top of the feed bed according to the substrate consumption. The amount of replenishment should be enough to cover the exposed larvae.

[0012] Step Four: After a rearing cycle of 35-45 days, harvest the larvae by grading them using sieves of different mesh sizes. First, use an 8-mesh sieve (2.36 mm in diameter) to separate the mature larvae. Then, use a 30-mesh sieve (0.6 mm in diameter) to separate the frass from the young larvae and eggs. The harvested mature larvae are used to process protein powder or extract oil; the frass is used as organic fertilizer; and the young larvae and eggs are returned to the system for continued rearing.

[0013] Furthermore, in step one, the compound microbial agent is composed of Aspergillus niger, Protozoa flavovirens and Saccharomyces cerevisiae, with an effective live bacteria ratio ranging from (2~3):(1~2):(1~1.5).

[0014] 3. The method according to claim 1 or 2, characterized in that, in step one, the aerobic fermentation process involves turning the pile regularly, at a frequency of once every 2 to 3 days, to ensure that the temperature at the center of the fermentation pile is maintained at 40 to 50°C.

[0015] Furthermore, in step two, the multi-layer breeding rack has 3 to 5 layers, with a layer spacing of not less than 40 centimeters, to facilitate operation and ensure ventilation.

[0016] Furthermore, in step three, the dynamic replenishment based on substrate consumption is determined by the following criteria: replenishment is carried out when more than 30% of the larvae are exposed on the surface of the substrate bed.

[0017] Furthermore, in step three, the material bed is turned over manually or mechanically, with a turning depth of 10-15 cm, in order to avoid damaging the larval habitat at the bottom of the material bed.

[0018] Furthermore, in step four, the specific operation of graded harvesting is as follows: first, the entire material bed is passed through an 8-mesh sieve, and the material that passes through the sieve is mature larvae; then, the material that passes through the 8-mesh sieve is passed through a 30-mesh sieve, and the material that passes through the sieve is young larvae and eggs, while the material that passes through the sieve is insect excrement and sand.

[0019] Furthermore, in step four, the processing method of the mature larvae is as follows: after being purified by fasting in clean water for 24 to 48 hours, they are directly freeze-dried and pulverized to make insect protein powder, or they are pressed to extract oil and then the insect residue is dried to make defatted insect protein powder.

[0020] Furthermore, in step four, the separated young larvae and eggs are directly mixed with an appropriate amount of fresh pretreated drug residue substrate and returned to the breeding system in step two as the source of insects for subsequent batches of cultivation.

[0021] The technical effects and advantages of this invention are as follows:

[0022] 1. By utilizing the vigorous feeding and digestive capabilities of the white-spotted flower beetle larvae, the treatment cycle of medicinal residue is shortened to 35-45 days, which is significantly longer than traditional composting, achieving rapid reduction of waste and realizing both high efficiency and volume reduction.

[0023] 2. By transforming waste medicinal residue into two high-value products—insect protein (larvae) and organic fertilizer (insect excrement sand)—we have turned waste into treasure, creating significant economic benefits and forming a virtuous cycle of "processing-output".

[0024] 3. The entire treatment process is a biological transformation, which does not produce secondary pollution, has low energy consumption, and is in line with the development concept of carbon neutrality and circular economy.

[0025] 4. The required equipment is simple, and the feeding and management are convenient. It is suitable for promotion and application in places of different sizes, such as Chinese medicine factories and farms.

[0026] 5. The obtained larval protein is a high-quality feed for poultry, aquatic products, and special breeding; the insect excrement sand has mild fertility, is loose and breathable, and is an ideal fertilizer for high-end flowers and organic agriculture, with high product value. Detailed Implementation

[0027] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0028] Example 1: A method for treating medicinal residue using white-spotted flower beetle larvae provided by the present invention;

[0029] Step 1: After crushing the fresh medicinal residue with a moisture content of 75%-85%, inoculate it with a compound microbial agent, including but not limited to one of cellulose-degrading bacteria, lignin-degrading bacteria and yeast, and ferment it aerobically at 40-50℃ for 7-15 days to obtain a pretreated medicinal residue matrix; the inoculation amount of the compound microbial agent is 0.5%-2% of the weight of the medicinal residue.

[0030] Table 1: Effect of different fermentation pretreatment times on system output efficiency

[0031] Fixed conditions: 80% moisture content of medicinal residue, 1% inoculum amount, fermentation temperature 45℃; breeding density 1.25 kg / m² for 2nd instar larvae and 0.65 kg / m² for 1st instar larvae, ambient temperature 27.5℃, humidity 65%, breeding cycle 40 days.

[0032] Fermentation time (days) Cellulose degradation rate (%) Larval weight gain per unit area (kg / m²) Insect frass yield per unit area (kg / m²) 7 45.5 2.43 3.53 10 58.3 2.80 4.20 15 62.5 3.00 4.50

[0033] Table 1

[0034] Note: The data in this table show that controlling the fermentation time to 10 to 15 days can significantly improve the degradation efficiency of cellulose, thereby increasing larval biomass and the yield of frass, demonstrating the technical advantages of the optimized fermentation time range.

[0035] The compound microbial agent is composed of Aspergillus niger, Protozoa flavovirens and Saccharomyces cerevisiae, with an effective live bacteria ratio of (2~3):(1~2):(1~1.5).

[0036] The main objective was to construct an efficient "hierarchical degradation-nutrient synergy" metabolic pathway. *Aspergillus niger*, as a cellulose-degrading bacterium, constituted the largest proportion of this pathway, responsible for rapidly secreting large amounts of cellulase, hemicellulase, and pectinase in the early stages of fermentation. These enzymes quickly break down the robust plant cell wall structure in the residue, opening pathways for subsequent microbial action. Simultaneously, *Aspergillus niger* produces certain organic acids during its growth; this slightly acidic environment helps activate other enzyme systems and inhibits some contaminating microorganisms. Its high proportion provides a powerful initial impetus for the entire degradation process.

[0037] *Protozoa huangsporea*, a well-known lignin-degrading bacterium, secretes lignin peroxidase and manganese peroxidase, which are key to depolymerizing complex lignin molecules. Building upon the initial disintegration of the fibrous structure by *Aspergillus niger*, *Protozoa huangsporea* can more effectively access and attack lignin encapsulated by cellulose and hemicellulose, achieving complete degradation of the most difficult-to-degrade components in the pesticide residue. This constitutes a "cellulose-first, wood-later" degradation sequence, with a suitable proportion to ensure the successful overcoming of stubborn structures without excessive carbon source consumption.

[0038] Saccharomyces cerevisiae: Yeast plays multiple key roles in this system: Rapid colonization and niche occupation: Yeast grows rapidly, quickly consuming some of the simple sugars produced in the early stages of fermentation, seizing ecological niches, effectively inhibiting the growth of other putrefactive bacteria and miscellaneous microorganisms, and ensuring the smooth progress of the fermentation process. Nutrient conversion and preservation: Yeast assimilates easily lost carbon sources into cell proteins, fixing carbon and nitrogen sources, reducing nutrient loss and the volatilization of odors (such as ammonia) during fermentation. Provision of metabolic cofactors: The metabolic products of yeast (such as vitamins and amino acids) can stimulate and promote the growth and enzyme activity of Aspergillus niger and Protozoa flavoviridae, playing a synergistic role of "nutritional complementarity".

[0039] It maintained the microecological balance and stability of the fermentation system;

[0040] By controlling the proportions within the above range, it can be ensured that the growth rhythms and metabolic functions of the three microorganisms are matched during the fermentation process, forming a dynamically balanced micro-ecosystem.

[0041] If the proportion of Aspergillus niger is too low, the initial cell wall breaking speed will be slow, affecting the overall efficiency.

[0042] If the proportion of Proteobacterium flavonoides is too high, it may excessively consume carbon sources for its own growth, but its ability to directly degrade cellulose is not strong, resulting in energy waste in the early stage.

[0043] If the proportion of yeast is too high, it will excessively compete with Aspergillus niger for the simple sugars needed, thus inhibiting the initial degradation of cellulose; if the proportion is too low, it will not effectively inhibit other microorganisms, and the preservation and conversion of nutrients will be insufficient. The specific ratio of the present invention precisely avoids the above-mentioned drawbacks, so that the three complement each other and work together to maintain a stable high temperature of 40-50°C in the fermentation pile, and accelerate the humification process of the medicinal residue.

[0044] This provides ideal substrate conditions for subsequent larval rearing;

[0045] The substrate obtained through pretreatment with this synergistic microbial agent has the following characteristics that are beneficial to the feeding and growth of white-spotted beetle larvae: cellulose and lignin are effectively degraded, making the substrate loose and soft, facilitating larval burrowing and feeding. The metabolic process of the microbial agent converts large organic molecules into small-molecule sugars, organic acids, and microbial proteins that are easily absorbed by larvae, improving the nutritional value of the substrate. The antibacterial effect of yeast and the high-temperature fermentation process significantly reduce the content of original pathogens in the substrate, providing a healthier growth environment for larvae.

[0046] During the aerobic fermentation process, the compost pile is turned regularly, every 2-3 days, to ensure the center temperature of the fermentation pile is maintained at 40-50℃. Its core function is to ensure a sufficient oxygen supply and maintain a strictly aerobic environment.

[0047] Meeting the respiratory needs of microorganisms: The compound microbial agents used in this invention (Aspergillus niger, Protozoa flavovirens, and Saccharomyces cerevisiae) are all aerobic or facultative anaerobic microorganisms. They consume large amounts of oxygen when decomposing macromolecular organic matter such as cellulose and lignin. Turning the compost pile quickly introduces fresh air into the fermentation pile, directly providing these highly efficient degrading bacteria with the oxygen necessary for their life activities, thus maintaining their vigorous metabolic activity.

[0048] Suppressing harmful anaerobic bacteria: If the compost pile is not turned in time, the center of the fermentation pile will quickly transform into an anaerobic environment due to lack of oxygen. This will lead to the proliferation of anaerobic microorganisms such as putrefactive bacteria (e.g., butyric acid bacteria) and methanogens, which not only consume available nutrients but also produce foul-smelling and harmful gases such as hydrogen sulfide, ammonia, and methane, causing serious losses of nutrients such as nitrogen and producing unpleasant odors that pollute the environment. Regularly turning the compost pile can effectively disrupt the anaerobic environment, inhibit the growth of harmful bacteria, and ensure that the fermentation process proceeds in the correct direction of harmlessness and resource utilization.

[0049] Key controls are employed to maintain the optimal temperature window (40~50℃) for efficient fermentation.

[0050] Promoting Heating and Preventing Overheating: In the early stages of fermentation, turning the pile helps to mix the materials evenly, promotes rapid microbial reproduction, and thus accelerates the heating of the pile, allowing it to quickly enter the efficient high-temperature phase. When the pile temperature is too high (e.g., exceeding 60°C), it will inhibit or even kill the functional microbial agents used in this patent (the optimal temperature for Aspergillus niger and Protozoa flavus is usually in the range of 40-50°C). Regular turning of the pile can effectively dissipate excess heat through evaporative cooling and the introduction of low-temperature air, preventing the pile from "scorching dry" or experiencing temperature runaway, and precisely maintaining the core temperature within the optimal range of 40-50°C.

[0051] Maintaining uniform temperature and eliminating "cold spots": The turning process ensures thorough mixing and exchange of materials between the inside and outside of the fermentation pile. Warm, moist materials are turned to the outside, where they can be reheated; cooler materials are turned inside, where they undergo high-temperature sterilization and rapid degradation. This process eliminates "cold spots" and "hot spots" in the fermentation pile, ensuring uniform heating and consistent fermentation throughout the entire pile, avoiding problems such as incomplete or over-fermentation in certain areas.

[0052] Optimize the physical structure and chemical homogeneity of the fermentation substrate;

[0053] Breaking up clumps and improving structure: Under the action of microorganisms, medicinal residue materials are prone to clumping due to mycelial entanglement and moisture. Turning the pile, especially using mechanical turning, can effectively break up these clumps, maintaining a loose and porous physical structure. This not only facilitates oxygen circulation and heat transfer but also provides a substrate form that is easier for larvae to burrow into and feed on.

[0054] Homogenization promotes reaction: Turning the pile allows the materials, moisture, microorganisms, and intermediate metabolites to be remixed evenly. This ensures sufficient contact between microorganisms, enzymes, and substrate (drug residue), improving the efficiency and thoroughness of the degradation reaction and avoiding localized acidification or spoilage caused by uneven material distribution.

[0055] Improve the quality of pretreated substrate and the subsequent aquaculture effect;

[0056] Shortening the fermentation cycle and regular turning management ensure that the entire fermentation system is always in the optimal biochemical reaction state, thus enabling efficient pretreatment to be completed within 7-15 days. Compared with traditional treatments that do not turn the pile or turn it in a timely manner, the cycle is significantly shortened and efficiency is improved.

[0057] This pretreated substrate, which lays the foundation for larval rearing, is ideal for the larvae of the white-spotted flower beetle due to its loose structure, rich nutrients, and absence of harmful substances and pathogens. This directly ensures a high survival rate, rapid growth, and high conversion efficiency for the subsequent larvae.

[0058] Example 2; Step 2: Place the pretreated drug residue substrate obtained in Step 1 on a multi-layer breeding rack, with each layer of substrate being 15-25cm thick. First, inoculate 2nd instar white-spotted flower beetle larvae at an inoculation density of 1.0-1.5 kg / m²; after 5-7 days, evenly supplement the surface layer of the same substrate with 1st instar white-spotted flower beetle larvae at an inoculation density of 0.5-0.8 kg / m².

[0059] Table 2: Effects of different initial inoculation densities on larval yield and survival rate

[0060] Fixed conditions: Pre-treatment fermentation for 10 days; Aquaculture environment temperature 27.5℃, humidity 65%, cycle 40 days.

[0061] Inoculation density of 2nd instar larvae (kg / m²) Final larval biomass (kg / m²) Insect frass production (kg / m²) Larval survival rate (%) 1.0 3.20 4.00 95.0 1.25 3.80 4.50 93.0 1.5 4.20 4.80 90.0

[0062] Table 2

[0063] Note: As shown in Table 2, when the inoculation density is 1.25 kg / m², it is possible to obtain ideal larval biomass and frass production while maintaining a high survival rate (93%), thus achieving the best balance between breeding efficiency and benefits.

[0064] Example 3: Step 3, control the breeding environment temperature at 25-30℃ and humidity at 60%-70%. Turn the feed bed over every 5 days, and dynamically replenish the fresh pretreated drug residue substrate prepared in Step 1 from the top of the feed bed according to the substrate consumption. The amount of replenishment should be enough to cover the exposed larvae.

[0065] Table 3: Effects of ambient temperature on growth cycle and products

[0066] Fixed conditions: pre-treatment fermentation for 10 days; stocking density: 1.25 kg / m² for 2nd instar larvae, 0.65 kg / m² for 1st instar larvae, humidity 65%.

[0067] Ambient temperature (°C) Larval weight gain per unit area (kg / m²) The time required to reach the standard (in days) Insect frass yield per unit area (kg / m²) 25 2.50 45.0 3.80 27.5 2.80 40.0 4.20 30 3.00 35.0 4.50

[0068] Table 3

[0069] Note: The data in this table demonstrates that controlling the ambient temperature at 25-30°C, especially around 27.5°C, can effectively accelerate larval growth, shorten the breeding cycle, and increase the yield of the final product, reflecting the optimized control of environmental parameters in this invention.

[0070] Example 4: Step 4, after a rearing cycle of 35-45 days, harvest the larvae by grading using sieves of different aperture sizes. First, use an 8-mesh sieve (2.36 mm in diameter) to separate mature larvae. Then, use a 30-mesh sieve (0.6 mm in diameter) to separate the frass from the young larvae and eggs. The harvested mature larvae are used to process protein powder or extract oil; the frass is used as organic fertilizer; and the young larvae and eggs are returned to the system for continued rearing.

[0071] Table 4: Effect of inoculum size of compound microbial agent on pretreatment effect

[0072] Fixed conditions: fermentation time 10 days, moisture content 80%, fermentation temperature 45℃; breeding cycle 40 days, ambient temperature 27.5℃.

[0073] Inoculum amount (%) Cellulose degradation rate (%) Larval weight gain per unit area (kg / m²) Insect frass yield per unit area (kg / m²) 0.5 50.4 2.20 3.60 1.0 58.3 2.80 4.20 2.0 60.5 3.00 4.40

[0074] Table 4

[0075] Note: As shown in Table 4, when the inoculum amount is 1.0%, key indicators such as cellulose degradation rate have been significantly improved. Compared with the inoculum amount of 2.0%, it is more cost-effective, thus supporting the preferred range of 0.5%-2% in the claims.

[0076] It should also be noted that the multi-layer breeding rack has 3-5 layers, with a minimum spacing of 40 cm between layers, to facilitate operation and ensure ventilation. The substrate should be dynamically replenished based on consumption; the criterion for this is that replenishment should be made when more than 30% of the larvae are exposed on the surface of the substrate bed.

[0077] It is important to note that the larvae of the white-spotted flower beetle exhibit strong negative phototaxis, preferring dark, moist soil environments. When the substrate is depleted and thinned, the larvae experience stress and discomfort when exposed to light. This stress leads to abnormal activity, increased energy consumption, decreased feeding efficiency, and even cannibalism. Using "larval exposure" as a signal to promptly replenish the covering is crucial to meeting their basic shelter needs, reducing stress, and ensuring normal physiological behavior. Feeding behavior and substrate structure: Larvae primarily bore into and feed within the substrate. When the substrate thickness is insufficient, not only is the total food supply inadequate, but the physical structure they rely on for burrowing is also damaged, preventing normal feeding activities. Exposed larvae are often "homeless and without food."

[0078] In step three, the feed bed is turned over manually or mechanically, with a turning depth of 10-15 cm, in order to avoid damaging the larval habitat at the bottom of the feed bed.

[0079] In step four, the specific operation of graded harvesting is as follows: First, the entire material bed is passed through an 8-mesh sieve, and the material that passes through the sieve is mature larvae; then, the material that passes through the 8-mesh sieve is passed through a 30-mesh sieve, and the material that passes through the sieve is young larvae and eggs, while the material that passes through the sieve is insect excrement and sand.

[0080] Table 5: Distribution and utilization of graded harvest products (average output of multiple batches under optimal conditions)

[0081] Harvested product categories Screen specifications Average yield per unit area (kg / m²) Main uses Mature larvae More than 8 mesh 3.80 Processing insect protein powder or extracting oil Young larvae and eggs 8-30 mesh 0.75 Returned to the system as a source of insects for subsequent batches. Insect excrement sand organic fertilizer 30 mesh or less 4.50 Used as a high-quality organic fertilizer

[0082] Note: Table 5 systematically shows the resource-based product structure achieved by the method of the present invention in a single processing flow, highlighting the high-value output model of "insect protein - insect excrement fertilizer - population continuation" and reflecting the comprehensive benefits of the present invention.

[0083] In step four, the mature larvae are processed as follows: after being purified by fasting in clean water for 24 to 48 hours, they are directly freeze-dried and pulverized to make insect protein powder, or they are pressed to extract oil and then the insect residue is dried to make defatted insect protein powder.

[0084] In step four, the separated young larvae and eggs are directly mixed with an appropriate amount of fresh pretreated drug residue substrate and returned to the breeding system in step two as the source of insects for subsequent batches of cultivation.

[0085] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for treating medicinal residue using white-spotted flower beetle larvae, characterized in that, Includes the following steps: Step 1: After crushing the fresh medicinal residue with a moisture content of 75%-85%, inoculate it with a compound microbial agent and ferment it aerobically at 40-50℃ for 7-15 days to obtain a pretreated medicinal residue matrix; the inoculation amount of the compound microbial agent is 0.5%-2% of the weight of the medicinal residue. Step Two: Place the pretreated drug residue substrate obtained in Step One on a multi-layer breeding rack, with each layer of substrate being 15-25cm thick. First, inoculate with 2nd instar white-spotted flower beetle larvae at a density of 1.0-1.5 kg / m². After 5-7 days, evenly supplement the surface layer of the same substrate with 1st instar white-spotted flower beetle larvae at a density of 0.5-0.8 kg / m². Step 3: Control the breeding environment temperature to 25-30℃ and humidity to 60%-70%. Turn the feed bed over every 5 days, and dynamically replenish the fresh pretreated drug residue substrate prepared in Step 1 from the top of the feed bed according to the substrate consumption. The amount of replenishment should be enough to cover the exposed larvae. Step Four: After a rearing cycle of 35-45 days, harvest the larvae by grading them using sieves of different mesh sizes. First, use an 8-mesh sieve (2.36 mm in diameter) to separate the mature larvae. Then, use a 30-mesh sieve (0.6 mm in diameter) to separate the frass from the young larvae and eggs. The harvested mature larvae are used to process protein powder or extract oil; the frass is used as organic fertilizer; and the young larvae and eggs are returned to the system for continued rearing.

2. The method according to claim 1, characterized in that, In step one, the compound microbial agent is composed of Aspergillus niger, Protozoa flavovirens and Saccharomyces cerevisiae, with an effective live bacteria ratio of (2~3):(1~2):(1~1.5).

3. The method according to claim 1 or 2, characterized in that, In step one, the aerobic fermentation process involves turning the pile regularly, every 2 to 3 days, to ensure that the temperature at the center of the fermentation pile is maintained at 40 to 50°C.

4. The method according to claim 1, characterized in that, In step two, the multi-layer breeding rack has 3 to 5 layers, with a layer spacing of not less than 40 centimeters, to facilitate operation and ensure ventilation.

5. The method according to claim 1, characterized in that, In step three, the dynamic replenishment based on substrate consumption is determined by the following criteria: when more than 30% of the larvae are exposed on the surface of the substrate bed, replenishment is carried out.

6. The method according to claim 1, characterized in that, In step three, the feed bed is turned over manually or mechanically, with a turning depth of 10-15 cm, in order to avoid damaging the larval habitat at the bottom of the feed bed.

7. The method according to claim 1, characterized in that, In step four, the specific operation of graded harvesting is as follows: First, the entire material bed is passed through an 8-mesh sieve, and the material that passes through the sieve is mature larvae; then, the material that passes through the 8-mesh sieve is passed through a 30-mesh sieve, and the material that passes through the sieve is young larvae and eggs, while the material that passes through the sieve is insect excrement and sand.

8. The method according to claim 1, characterized in that, In step four, the mature larvae are processed as follows: after being purified by fasting in clean water for 24 to 48 hours, they are directly freeze-dried and pulverized to make insect protein powder, or the larvae are pressed to extract oil and then the residue is dried to make defatted insect protein powder.

9. The method according to claim 1, characterized in that, In step four, the separated young larvae and eggs are directly mixed with an appropriate amount of fresh pretreated drug residue substrate and returned to the breeding system in step two as the source of insects for subsequent batches of cultivation.