Method for preparing low-salt organic fertilizer and high-salt protein feed by processing kitchen waste

Abstract

The invention discloses a method for preparing low-salt organic fertilizer and high-salt protein feed by treating kitchen waste. The method comprises the following steps: solid-liquid separation of the kitchen waste, collecting a liquid part for standby use, removing non-degradable impurity components from a solid part to obtain solid degradable organic waste, and then mixing the solid degradable organic waste with crop straw to obtain mixed organic waste with a C / N ratio of 18 to 35:1; mixing the mixed organic waste with the liquid part to obtain a mixed material with a water content of 50 wt.% to 70 wt.%; inoculating salt-tolerant microorganisms into the mixed material, culturing the mixed material for a period of time, and then adding 1-2 instar white star flower beetle larvae for breeding; after the 1-2 instar white star flower beetle larvae are all transformed into 3-instar mature larvae, separating the mature larvae from insect sand for treatment; air-drying the insect sand in the sun or drying it to obtain low-salt granular organic fertilizer, and suffocating and killing the mature larvae and drying them to obtain high-salt protein feed.

Description

Technical Field

[0001] The invention relates to the technical field of restaurant kitchen waste treatment and resource utilization, and in particular to a method for preparing economic products of low-salt organic fertilizer and high-salt protein feed by using an insect-bacteria symbiotic system of white-spotted flower beetle larvae and salt-tolerant microorganisms to ecologically treat restaurant kitchen waste. Background Art

[0002] Kitchen waste has the characteristics of high salt, high water content and high organic matter. It is both a resource and a pollutant. It is beneficial if used but harmful if discarded. If handled properly, it can be "turned into treasure", but if handled improperly, it will pollute the environment and harm health. Traditional non-biological technologies such as landfill, incineration, and feed production have problems such as secondary pollution. The currently promoted and applied biological technologies such as anaerobic fermentation and aerobic composting are green and environmentally friendly, but their operation and management level is high. The salt content of organic fertilizer is relatively high, and the salt content needs to be reduced through processes such as water washing.

[0003] In recent years, the use of insects (white-spotted flower beetle larvae, black soldier flies and yellow mealworms, etc.) to treat food waste has attracted people's attention. Patent applications CN103976153A and CN108605898A disclose a method for treating food waste using microorganisms (composite bacterial agents, stropharia species) and white-spotted flower beetle larvae. Due to the complex composition of food waste, patent application CN110896925A discloses a method for converting food waste using yellow mealworms, black soldier flies and white-spotted flower beetles. The above method is simple and has low energy consumption. However, due to the "three highs" characteristics of food waste and low carbon-nitrogen ratio (C / N) ratio, conventional microorganisms and white-spotted flower beetle larvae (or other insects) are difficult to effectively process and convert, and there are problems such as high larval mortality, and the obtained organic fertilizer has a high salt content, which limits its promotion and application to a certain extent.

[0004] Effective management of kitchen waste and crop straw waste is the "two major problems" in recent years. If these waste resources are not effectively utilized and processed, it will cause great waste of resources and environmental pressure. Patent applications CN102987076A, CN111903878A and CN114149277A disclose a method for transforming agricultural solid organic waste using white-spotted flower beetles to obtain economic products such as insect bodies and insect sand. The above method uses crop straw as the main material and livestock and poultry manure (or added bacterial agents) as the auxiliary material. After fermentation and composting (ranging from 15 to 90 days), the white-spotted flower beetle larvae are used for processing and transformation. The time period is long and the process is cumbersome.

[0005] In summary, there are certain technical difficulties in using white-spotted flower beetle larvae to treat single organic wastes such as food waste or crop straw, and a solution with strong practical feasibility is needed. However, there are few reports on coupling food waste and crop straw, regulating the moisture, nutrients and C / N ratio of the two types of organic wastes, and using the symbiotic transformation of white-spotted flower beetle larvae and salt-tolerant microorganisms. Summary of the invention

[0006] The present invention provides a method for preparing low-salt organic fertilizer and high-salt protein feed by processing restaurant kitchen waste, fully exploits the characteristics of white-spotted flower beetle larvae and salt-tolerant microorganisms, follows the laws of nature, integrates restaurant kitchen waste and crop straw into ecological management, and realizes resource utilization and harmless treatment of the two types of organic waste. The method of the present invention does not require decomposition, takes a short time, has high efficiency, is green and low-carbon, has no secondary pollution, treats waste with harm, turns waste into treasure, realizes synergistic efficiency of pollution reduction and carbon reduction, and has broad application prospects.

[0007] A method for preparing low-salt organic fertilizer and high-salt protein feed by processing kitchen waste, comprising the steps of:

[0008] (1) separating the solid and liquid of the kitchen waste, collecting the liquid part for future use, and removing the non-degradable impurity components from the solid part to obtain solid degradable organic waste;

[0009] (2) mixing the solid degradable organic waste with crop straw to obtain mixed organic waste with a C / N ratio of 18 to 35:1;

[0010] (3) mixing the mixed organic waste with the liquid portion in step (1) to obtain a mixed material having a water content of 50 wt.% to 70 wt.%;

[0011] (4) inoculating salt-tolerant microorganisms into the mixed material and culturing for a period of time, and then adding 1-2-year-old white-spotted flower beetle larvae for breeding;

[0012] (5) After the 1st to 2nd instar larvae of the white-spotted flower beetle have all turned into 3rd instar mature larvae, the mature larvae are separated from the insect sand: the insect sand is air-dried or oven-dried to obtain low-salt granular organic fertilizer, and the mature larvae are suffocated to death and dried to obtain high-salt protein feed.

[0013] The present invention couples food waste with crop straw and can recycle the liquid components in the food waste. There is no need to perform subsequent separate treatment on the liquid components in the food waste. The "insect-bacteria symbiosis system" (white-spotted flower beetle larvae + salt-tolerant microorganisms) is developed for collaborative treatment to obtain economic products such as low-salt organic fertilizer and high-salt protein feed, which can be extended to ecological planting and breeding industries, thus promoting the green and low-carbon development of agricultural ecology.

[0014] In one embodiment, in step (2), the particle size of the solid degradable organic waste is 0.1-1.0 cm, and the particle size of the crop straw is 0.5-1.0 cm.

[0015] In step (2), the crop straw may include one or more of rice straw, wheat straw, corn straw, cotton straw, etc.

[0016] In step (4), the salt-tolerant microorganisms include one or more of salt-tolerant COD-degrading bacteria, marine inhibitory bacteria, and marine water-purifying bacteria. In one embodiment, in step (4): the salt-tolerant COD-degrading bacteria are aerobic salt-tolerant bacteria for COD reduction in sewage treatment sold by Shanghai Bilaiqing Biotechnology Co., Ltd. (implementation standard: Q / BANB103-2019), purchase link: https: / / detai l.1688.com / offer / 615544881302.html? _t=1687162836320&spm=a2615.7691456.co_0_0_wangpu_score_0_0_0_0_0_0_0_0000_1.0; The marine inhibitory bacteria are the bacterial agents used to inhibit harmful (marked as Health) in the CS seawater whole bacteria of the German Coral Surprise brand (implementation standard: Q / KARS J1.1-2022), purchase link: https: / / item.taobao.com / item.htm? spm=a1z09.2.0.0.27b02e8dlVOyM9&id=662633165166&_u=iatn7tr a122; The marine water purifying bacteria is a bacterial agent used for water purification and algae inhibition (marked as Purify) in the CS seawater whole bacteria of the German Coral Surprise brand (implementation standard: Q / KARS J1.1-2022), purchase link: https: / / item.taobao.com / item.htm? spm=a1z09.2.0.0.27b02e8dlVOyM9&id=662633165166&_u=iatn7tra122.

[0017] Taking into account the larval activity and the desalination effect, it is preferred that in step (4), based on the mass of the mixed material, the inoculation amount of the salt-tolerant microorganisms is 0.1wt.% to 0.5wt.%. Too much inoculation amount of salt-tolerant microorganisms can easily cause larval death, and the number of viable bacteria in the salt-tolerant microorganisms is ≥10 billion / gram.

[0018] In a preferred example, in step (4), the specific operation of inoculating salt-tolerant microorganisms into the mixed material and culturing for a period of time includes: spreading the mixed material evenly in a breeding box with a thickness of 5 to 8 cm, and culturing for 2 to 5 days after inoculating the salt-tolerant microorganisms to allow the salt-tolerant microorganisms sufficient time to activate.

[0019] Preferably, in step (4), the temperature of the culturing and the breeding is 20-35°C.

[0020] Based on the conversion rate of larvae to materials, in step (4), the mass ratio of the amount of first-instar flower beetle larvae to the mixed material is preferably 1.0-3.0:10, and the mass ratio of the amount of second-instar flower beetle larvae to the mixed material is preferably 2.0-3.0:5.

[0021] In one embodiment, in step (4), the insect sand is screened out with a sieve every 10 days during the breeding period, and the water content of the mixed material is regularly adjusted to between 50wt.% and 70wt.% with the liquid portion described in step (1). If the mixed material is completely converted during the breeding period, the mixed material is supplemented.

[0022] Preferably, in step (5), the salt content in the low-salt granular organic fertilizer is Cl - The organic matter content is 1.5wt.% to 2.1wt.%, the organic matter content is 28wt.% to 36wt.%, and the humic acid content is 5.0wt.% to 7.5wt.%.

[0023] Preferably, in step (5), the protein content of the high-salt protein feed is 48.5wt.% to 55.0wt.%, and the salt content is Cl - Calculated as 0.2wt.%~0.5wt.%.

[0024] In summary, in order to overcome the problems of high salt content, low treatment efficiency (high insect mortality rate), long cycle and the like in the prior art of organic fertilizer made from kitchen waste, the present invention provides a method for ecologically transforming kitchen waste by using an "insect-bacteria symbiotic system" constructed by white-spotted flower beetle larvae and salt-tolerant microorganisms, wherein the carbon-nitrogen ratio of kitchen waste is adjusted to an appropriate value by using crop straw, and the liquid part of the kitchen waste is fully utilized without the need for a composting process, and on this basis, the salt-tolerant microorganisms are utilized to adapt to high-salt environments and to enrich salt, and the characteristics of the saprophagous nature of white-spotted flower beetle larvae are utilized to treat kitchen waste with "three highs" of high salt, high water content and high organic matter, and obtain economic products such as low-salt organic fertilizer and high-salt protein feed (additive).

[0025] The present invention provides a method for transforming restaurant kitchen waste using an insect-bacteria symbiotic synergistic system of white-spotted flower beetle larvae and salt-tolerant microorganisms, including pretreatment of organic waste from restaurant kitchen waste, inoculation of salt-tolerant microorganisms, introduction of white-spotted flower beetle larvae, biological transformation of the insect-bacteria symbiotic system, and post-treatment of finished insects and insect sand. Compared with the prior art, the present invention has the following beneficial effects:

[0026] 1. The insect-fungus symbiotic system can solve the problem of high salt content in preparing organic fertilizer from food waste, and obtain economical products of low-salt organic fertilizer and high-salt protein feed.

[0027] 2. The coupling of restaurant kitchen waste with crop straw can effectively regulate the moisture, nutrients and C / N ratio of aquaculture raw materials, save water and processing cycle, and the survival rate (mortality rate is less than 11%) and conversion rate of white-spotted flower beetle larvae are high.

[0028] 3. Realize the reduction, harmlessness, resource utilization and low (zero) carbonization of waste such as kitchen waste and crop straw, treat waste with harm, and turn waste into treasure, which has the advantages of synergistic efficiency in reducing pollution and carbon emissions. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 The present invention is a process flow diagram of a method for preparing low-salt organic fertilizer and high-salt protein feed by treating restaurant kitchen waste. DETAILED DESCRIPTION

[0030] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and are not used to limit the scope of the present invention.

[0031] The present invention uses an insect-fungus symbiotic synergistic system of white-spotted flower beetle larvae and salt-tolerant microorganisms to ecologically treat food waste, thereby obtaining economic products such as low-salt organic fertilizer and high-salt protein feed, which has very important practical significance for solving the increasingly serious environmental pollution caused by food waste and the problem that organic fertilizer prepared from food waste usually has a high salt content.

[0032] See also Figure 1 , a method for preparing low-salt organic fertilizer and high-salt protein feed by processing kitchen waste, comprising the steps of:

[0033] (1) The solid-liquid separation of the kitchen waste is carried out, the liquid part is collected for future use, and the non-degradable impurities in the solid part are removed to obtain solid degradable organic waste, and the impurities can be recycled or treated harmlessly;

[0034] (2) crushing the solid degradable organic waste and mixing it with crop straw particles to obtain mixed organic waste with a C / N ratio of 18 to 35:1;

[0035] (3) mixing the mixed organic waste with the liquid portion in step (1) to obtain a mixed material having a water content of 50 wt.% to 70 wt.%;

[0036] (4) inoculating salt-tolerant microorganisms into the mixed material and culturing for a period of time, and then adding 1- to 2-year-old white-spotted flower beetle larvae for cultivation; the salt-tolerant microorganisms include one or more of salt-tolerant COD-degrading bacteria, marine inhibitory bacteria, and marine water-purifying bacteria;

[0037] (5) After the 1st to 2nd instar larvae of the white-spotted flower beetle have all turned into 3rd instar mature larvae, the mature larvae are separated from the insect sand: the insect sand is air-dried or oven-dried to obtain low-salt granular organic fertilizer, and the mature larvae are suffocated to death and dried to obtain high-salt protein feed.

[0038] Specifically, in the following embodiments, the method for converting food waste using the insect-bacteria symbiotic synergistic system of white-spotted flower beetle larvae and salt-tolerant microorganisms provided by the present invention comprises the following steps:

[0039] 1) After the solid-liquid separation of the received kitchen waste, the solid is sorted, impurity-removed, crushed and other processes to obtain a granular material with a size of 0.1 to 1.0 cm, which is mixed with the crushed crop straw auxiliary material (size of 0.5 to 1.0 cm). Referring to Experimental Schemes 2, 4, 5 and 6 in Table 1, the crop straw is rice straw, and the mass ratio of the crop straw to the degradable solid granular material of kitchen waste is 50:50, and the C / N ratio of the obtained mixture is 20 to 22:1. The present invention also compares pure kitchen waste degradable solid granular material with a size of 0.1 to 1.0 cm (Experimental Scheme 1, C / N ratio of 13 to 15:1) and pure rice straw granular material with a size of 0.5 to 1.0 cm (Experimental Scheme 3, C / N ratio of 43 to 45:1).

[0040] The liquid from the solid-liquid separation of food waste is used to adjust the water content of the above mixture (or pure food waste degradable solid particles, or pure rice straw particles) to between 50wt.% and 70wt.%, and then the particles of the water-containing mixture are evenly spread in the breeding box with a spreading thickness of between 5 and 8 cm.

[0041] 2) Inoculate salt-tolerant microorganisms into the above-mentioned aqueous mixed material, the inoculation amount of the salt-tolerant microorganisms is 0.25wt.% (based on the mass of the above-mentioned aqueous mixed material), the number of viable bacteria in the salt-tolerant microorganisms is ≥10 billion / gram, and experimental scheme 4 without inoculation of salt-tolerant microorganisms is set as a comparison, the temperature is controlled at 20-35°C, and the culture is carried out for 2-3 days; then 1-2 instar white-spotted flower beetle larvae are released, wherein the mass ratio of the release amount of the 1-instar larvae to the aqueous mixed material is 1:5, and the mass ratio of the release amount of the 2-instar larvae to the aqueous mixed material is 2:5. The salt-tolerant microorganisms enter the intestines of the larvae as they eat, forming a "worm-bacteria" community.

[0042] 3) During the breeding period, the insect sand is screened out with a sieve every 10 days; the mature larvae of the 3rd age are picked out, one part is used as the source larvae, and the other part is processed into commercial larvae; at the same time, the water content of the aqueous mixture is adjusted to between 50wt.% and 70wt.% every 5 days with the liquid separated from the solid-liquid separation of the kitchen waste; after the aqueous mixture is completely converted, the aqueous mixture is continuously added to the breeding box.

[0043] 4) At the end of the breeding period (about 1 to 2 months), the larvae have all turned into mature 3rd-instar larvae, and the mature larvae are separated from the worm sand; the worm sand is air-dried or baked in the sun to obtain low-salt granular organic fertilizer, which can be used in agricultural planting; the mature larvae are suffocated to death and dried in a vacuum drying oven, and then crushed to obtain high-salt protein feed (additive), which can be directly used in livestock and poultry and fishery breeding without adding additional salt.

[0044] Table 1 shows the effects of different coupled raw materials and salt-tolerant microorganisms on the main indicators of high-salt protein feed (larvae) and low-salt granular organic fertilizer (worm sand).

[0045] Table 1

[0046]

[0047] Note: In Table 1, [1], [2], and [3] all represent the raw material ratio, specifically the mass ratio of rice straw to degradable solids of food waste, and the corresponding C / N ratios are 13-15:1, 20-22:1, and 43-45:1, respectively. Experimental schemes 1 to 3 were all inoculated with M3 (salt-tolerant COD-degrading bacteria, an aerobic salt-tolerant bacteria for COD reduction in sewage treatment sold by Shanghai Bilaiqing Biotechnology Co., Ltd., implemented in accordance with Q / BANB103-2019, purchased Link: https: / / detail.1688.com / offer / 615544881302.html?_t=1687162836320&spm=a2615.7691456.co_0_0_wangpu_score_0_0_0_0_0_0_0000_1.0); [4] M0 is not inoculated with salt-tolerant microorganisms; [5] M1 is marine inhibitory bacteria (German Co Coral Surprise brand CS seawater bacteria used to inhibit harmful (marked as Health) bacteria, implementation standard: Q / KARSJ1.1-2022, purchase link: https: / / item.taobao.com / item.html?spm=a1z09.2.0.0.27b02e8dlVOyM9&id=662633165166&_u=iatn7tra122); [6] M2 is marine water purifying bacteria (German Coral Surprise brand CS seawater bacteria used to purify water and inhibit algae (marked as Purify) bacteria, implementation standard: Q / KARS J1.1-2022, purchase link: https: / / item.taobao.com / item.htm?spm=a1z09.2.0.0.27b02e8dlVOyM9&id=662633165166&_u=iatn7tra122); Experimental schemes 4, 5 and 6 are all breeding raw materials with a 50:50 ratio of rice straw: degradable solids of kitchen waste, that is, experimental schemes 4, 5, 6 are the same as experimental scheme 2 except that salt-tolerant microorganisms are not inoculated or the types of salt-tolerant microorganisms inoculated are different. The salt content in Table 1 is Cl - count.

[0048] As can be seen from Table 1, the salt content of the low-salt granular organic fertilizer obtained by the method of the present invention is Cl -The salt content of the high-salt protein feed obtained by the method of the present invention is 1.56wt.%-2.12wt.% (significantly lower than the salt content of 2.46wt.% in Experimental Scheme 1), the organic matter content is 28.51wt.%-35.76wt.%, and the humic acid content is 5.05wt.%-7.32wt.% (much higher than the humic acid content of 1.0wt.%-2.0wt.%) in conventional compost. It does not require granulation and further desalination, and can be directly used as a slow-release organic fertilizer for vegetable and crop planting; the protein content of the high-salt protein feed obtained by the method of the present invention is 48.71wt.%-54.39wt.% (higher than the protein content of 48.22wt.%) in Experimental Scheme 1, and the salt content is Cl - The content is 0.21wt.% to 0.45wt.%, and can be directly fed to livestock and poultry such as chickens, ducks, geese, pigs, fish, and fishery farming without adding additional salt.

[0049] The present invention utilizes the innovative technology of the symbiotic synergistic system of white-spotted flower beetle larvae and salt-tolerant microorganisms to treat restaurant kitchen waste, which can effectively solve the problem of difficult treatment of organic waste such as restaurant kitchen waste and crop straw. It has the characteristics of novel and simple treatment method, short cycle and low cost, no secondary pollution to the environment, synergistically improving pollution reduction and carbon reduction, and promoting the green and low-carbon development of my country's agriculture.

[0050] In addition, it should be understood that after reading the above description of the present invention, those skilled in the art may make various changes or modifications to the present invention, and these equivalent forms also fall within the scope defined by the claims attached to this application.

Claims

1. A method for preparing low-salt organic fertilizer and high-salt protein feed by processing kitchen waste, characterized in that: Includes steps: (1) The solid-liquid separation of food waste, the liquid part is collected for future use, and the non-degradable impurities in the solid part are removed to obtain solid degradable organic waste; (2) mixing the solid degradable organic waste and the crop straw in a mass ratio of 50:50 to obtain a mixed organic waste having a C / N ratio of 18 to 35:1; (3) mixing the mixed organic waste with the liquid portion in step (1) to obtain a mixed material having a water content of 50 wt.% to 70 wt.%; (4) inoculating salt-tolerant microorganisms into the mixed material and culturing for a period of time, and then adding 1-2-year-old white-spotted scarab beetle larvae for cultivation; the salt-tolerant microorganisms are salt-tolerant COD-degrading bacteria; based on the mass of the mixed material, the inoculation amount of the salt-tolerant microorganisms is 0.1wt.%~0.5wt.%, and the number of viable bacteria in the salt-tolerant microorganisms is ≥10 billion / g; (5) After all the 1-2 instar white-spotted flower beetle larvae have become 3-instar mature larvae, the mature larvae are separated from the insect sand and processed: the insect sand is air-dried or oven-dried to obtain low-salt granular organic fertilizer, and the mature larvae are suffocated to death and dried to obtain high-salt protein feed; the salt content of the low-salt granular organic fertilizer is expressed as Cl - The content of protein in the high-salt protein feed is 48.5wt.%~55.0wt.%, and the salt content is Cl - Calculated as 0.2wt.%~0.5wt.%.

2. The method according to claim 1, characterized in that In step (2), the particle size of the solid degradable organic waste is 0.1-1.0 cm, and the particle size of the crop straw is 0.5-1.0 cm.

3. The method according to claim 1 or 2, characterized in that: In step (2), the crop straw includes one or more of rice straw, wheat straw, corn straw, and cotton straw.

4. The method according to claim 1, characterized in that In step (4), the specific operation of inoculating the mixed material with salt-tolerant microorganisms and culturing for a period of time includes: evenly spreading the mixed material in a culture box, the thickness of the spread mixed material is 5 to 8 cm, and culturing for 2 to 5 days after inoculating the salt-tolerant microorganisms.

5. The method according to claim 1, characterized in that In step (4), the temperature of the culturing and the breeding is 20-35°C.

6. The method according to claim 1, characterized in that In step (4), the mass ratio of the amount of the first-stage white-spotted flower beetle larvae to the mixed material is 1.0-3.0:10, and the mass ratio of the amount of the second-stage white-spotted flower beetle larvae to the mixed material is 2.0-3.0:

5.

7. The method according to claim 1, characterized in that In step (4), the insect sand is screened out with a sieve every 10 days during the breeding period, and the water content of the mixed material is regularly adjusted to between 50wt.% and 70wt.% with the liquid part described in step (1). If the mixed material is completely converted during the breeding period, the mixed material is supplemented.

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