Method for promoting humification of vinegar residues

Abstract

The invention relates to the technical field of vinegar residue resource utilization, and particularly discloses a method for promoting humification of vinegar residues to solve the problems that vinegar residues are not thoroughly decomposed, namely the resourceful treatment effect is poor in an existing process for fermenting and composting by adopting the vinegar residues as raw materials, the method comprises the following steps: S1, preparing biogas slurry: performing anaerobic fermentation by adopting chicken manure, and filtering to obtain the biogas slurry; the obtained clear liquid is biogas slurry, and the obtained solid residue is biogas residue; s2, vinegar residue pretreatment: fresh vinegar residues are rinsed with biogas slurry and filtered out, and rinsed vinegar residues are obtained; s3, performing aerobic composting treatment: mixing the soaked vinegar residues with biogas residues and sawdust, and performing aerobic composting treatment to obtain vinegar residue compost. According to the invention, the biogas slurry is used for immersion cleaning of the vinegar residue, and the decay-promoting microbial inoculum is added at a specific time, such that the efficient decay of the vinegar residue can be effectively promoted, and the vinegar residue can fully act on the growth of plants.

Description

Technical Field

[0001] The present invention relates to the technical field of utilization of vinegar residue resources, and in particular, to a method for promoting the humification of vinegar residue. Background Art

[0002] Vinegar residue refers to the solid waste residue generated after producing edible vinegar with sorghum and other raw materials, and its main components are sorghum, rice husk, rice bran, etc. China is a major producer of edible vinegar. For every 1 kg of edible vinegar brewed, about 0.8 kg of vinegar residue will be generated. With the continuous development of the vinegar-making industry in China, the annual output of vinegar residue has reached 3 million tons. Due to the high water content, high acidity and high lignocellulose content in vinegar residue, for the large amount of vinegar residue generated, the traditional treatment methods are landfill or incineration, which greatly causes problems such as soil acidification and environmental pollution, and at the same time is an extreme waste of vinegar residue resources.

[0003] How to effectively treat vinegar residue, reduce environmental pollution and realize the reuse of vinegar residue resources is an important problem faced by the vinegar-making industry in recent years. In this regard, for example, the patent with the publication number CN114431109A proposes a soilless cultivation organic substrate mainly composed of vinegar residue and its preparation method. Using vinegar residue as the main component, combined with sheep manure, bacterial fertilizer, etc., through multi-process fermentation, composting and other treatments, an organic substrate for soilless cultivation is prepared, which can not only provide sufficient nutrients for plants, but also save labor, reduce soil-borne diseases, and improve the resource utilization degree of vinegar residue and the like.

[0004] However, vinegar residue belongs to organic acid and has a relatively high cellulose content. If directly subjected to anaerobic digestion treatment, since cellulose is not easily degraded, the hydrolysis process becomes the rate-limiting step of the whole process. Therefore, vinegar residue is prone to organic acid inhibition during single-phase continuous anaerobic digestion treatment, and the lag phase is relatively large. Thus, the existing single-phase anaerobic digestion can only operate at a low load and with low yield; in addition, due to the characteristics of high acid and high fiber, during the aerobic composting process of vinegar residue, the temperature rises slowly, the high-temperature period is short, and the composting is not thorough, thus affecting the effect of efficient resource treatment of vinegar residue. Summary of the Invention

[0005] The purpose of the present invention is to solve the problem that the existing process of using vinegar residue as raw material for fermentation composting has incomplete vinegar residue composting, that is, the resource treatment effect is poor.

[0006] The present invention is realized through the following technical solutions:

[0007] The present invention provides a method for promoting the humification of vinegar residue, including the following steps:

[0008] S1 Preparing biogas slurry: Anaerobic fermentation is carried out using chicken manure, filtered, and the obtained clear liquid is biogas slurry, and the obtained solid residue is biogas residue;

[0009] S2 vinegar lees pretreatment: fresh vinegar lees are washed with biogas slurry and filtered to obtain washed vinegar lees;

[0010] S3 performs aerobic composting treatment: the washed vinegar dregs are mixed with biogas residue and sawdust, and aerobic composting treatment is performed to obtain vinegar dregs compost.

[0011] Preferably, in step S1, the total solid content after anaerobic fermentation is 7-8% by mass, and the methane content is 60-65% by mass.

[0012] Preferably, in step S1, the biogas slurry obtained by filtration has a bicarbonate alkalinity of 8000-10000 mg / L and a pH value of 7.5-8.0.

[0013] Preferably, in step S2, the volume ratio of fresh vinegar grains to biogas slurry is 6-8:1, and the soaking time is 15-20 minutes.

[0014] Preferably, in step S3, the mass ratio of soaked vinegar grains, biogas residue and sawdust is 0.8-1.5:0.5-2:0.5-2.

[0015] Preferably, the carbon-nitrogen mass ratio of the material after the soaked vinegar grains are mixed with the biogas residue and sawdust is controlled to be 21-24%, and the moisture content is 50-60%.

[0016] Preferably, in step S3, during the aerobic composting process, the temperature is adjusted to 0.45-0.55 L·(min·kg) -1 Continue to ventilate.

[0017] Preferably, in step S3, when the temperature of the aerobic composting pile drops below 50°C, a decay-promoting agent is added.

[0018] Preferably, the decay-promoting bacteria agent includes Aspergillus fumigatus, and the amount of the decay-promoting bacteria agent added is 1-2‰ of the mass of the pile.

[0019] The technical solution of the present invention has the following beneficial effects:

[0020] The present invention uses vinegar lees as the main raw material and first uses biogas slurry for soaking, which can effectively separate the organic acids on its surface. Because biogas slurry contains a large amount of alkaline and buffer substances, such as ammonia nitrogen compounds, bicarbonates, and carbonates, the organic acids are dissolved and neutralized. At the same time, the biogas slurry can also adhere to the surface of the vinegar lees, effectively changing the high-acidity characteristics of the fresh vinegar lees surface. In addition, the organic acids are dissolved in the biogas slurry and can be further utilized to produce methane by refluxing the biogas slurry into the anaerobic fermentation system. Since the soaked vinegar lees have a high cellulose content, they can be mixed with other organic wastes for aerobic composting. By adding a decay-promoting agent at a specific time, the efficient decomposition of the vinegar lees can be effectively promoted, allowing them to more fully act on plant growth.

[0021] Among them, for the biogas slurry obtained from the anaerobic fermentation system with chicken manure as the main raw material, when combined with vinegar residue, it mainly involves acid-base neutralization, organic matter decomposition and the synergistic effect of microorganisms. The biogas slurry is rich in organic matter, nitrogen, phosphorus, potassium and anaerobic microorganisms, and its pH value is about 7-8, that is, it is usually weakly alkaline; while the vinegar residue contains a large amount of acetic acid and other organic acids such as lactic acid, and its pH value is about 2-4. After the two are mixed, the following reactions can occur: ① Acid-base neutralization: The acidity of the vinegar residue is neutralized with the alkalinity of the biogas slurry, releasing CO2 and generating heat, making the system tend to be neutral, with a pH value of about 6-7, which is more conducive to the growth and metabolism of later composting microorganisms and reduces the impact of acidity on microorganisms; ② Organic matter conversion: Acetic acid reacts with ammonium nitrogen in the biogas slurry to form ammonium acetate, improving the stability of nitrogen. At the same time, the remaining easily degradable organic matters such as cellulose and hemicellulose are further decomposed under the action of microorganisms, and humic acid-like substances may be produced; ③ Changes in microbial activity: The anaerobic bacteria in the biogas slurry may be inhibited due to the adjustment of pH and the presence of acetic acid, but the neutral environment is conducive to the activities of other aerobic microorganisms, promoting the humification of organic matter; ④ Nutrient integration: After mixing, the carbon-nitrogen ratio of the whole raw material is more balanced, and heavy metals may be complexed by organic acids, reducing biological toxicity. Description of the Drawings

[0022] Figure 1 It is a comparison chart of the pH values of biogas slurry with different liquid-solid ratios and water leaching in the test examples;

[0023] Figure 2 It is a comparison chart of the volatile acid-base alkalinity of biogas slurry with different liquid-solid ratios and water leaching in the test examples;

[0024] Figure 3 It is a comparison chart of the acetic acid concentration of biogas slurry with different liquid-solid ratios and water leaching in the test examples;

[0025] Figure 4 It is a comparison chart of the propionic acid concentration of biogas slurry with different liquid-solid ratios and water leaching in the test examples;

[0026] Figure 5 It is a comparison chart of the dissolved chemical oxygen demand of biogas slurry with different liquid-solid ratios and water leaching in the test examples;

[0027] Figure 6 It is a comparison chart of the cumulative methane production of anaerobic digestion of leached biogas slurry and non-leached biogas slurry in the test examples;

[0028] Figure 7 It is a comparison chart of the aerobic composting pile body temperature of leached vinegar residue and non-leached vinegar residue in the test examples;

[0029] Figure 8 It is a comparison chart of the dehydrogenase activity of aerobic composting of leached vinegar residue and non-leached vinegar residue in the test examples;

[0030] Figure 9 This is a comparison chart of the aerobic compost pile temperatures under different addition methods of the decay-promoting bacteria in the test example;

[0031] Figure 10 This is a comparison chart of dehydrogenase activity in aerobic compost with different addition methods of pro-rot bacteria in the test example;

[0032] Figure 11 The figure is a schematic diagram of the structure of the circulation device for soaking vinegar lees in the present invention.

[0033] Figure identification: 1-barrel, 2-porous plate, 3-buffer tank, 4-pump. DETAILED DESCRIPTION

[0034] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention are described clearly and completely below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall be followed; and where the manufacturers of the instruments, equipment, reagents, and raw materials used are not specified, they are all commercially available conventional products.

[0035] The present invention provides a method for promoting the humification of vinegar dregs, comprising the following steps:

[0036] (1) Vinegar lees pretreatment

[0037] Before the composting treatment, the fresh vinegar dregs are placed in a vinegar dregs soaking circulating flushing device, and the fresh vinegar dregs are soaked with biogas liquid, and the volume ratio of the fresh vinegar dregs to the biogas liquid is 6-8:1, and the soaking time is 15-20 minutes.

[0038] Among them, such as Figure 11 As shown, the circulation device for vinegar lees soaking includes a barrel body 1 and a plurality of stacked porous plates 2 mounted on the bottom of the barrel body 1. Fresh vinegar lees are placed between the two porous plates 2. Under the action of a pump 4, the biogas slurry is uniformly infiltrated into the vinegar lees from the bottom, and can fully react with the vinegar lees. The leachate overflows from the top of the barrel body 1 and flows into the buffer tank 3, and then flows into the bottom of the barrel body 1, thereby circulating. After the soaking is completed, the biogas slurry can be returned to the anaerobic fermentation system and anaerobically treated again at 37±2°C.

[0039] In the present invention, the biogas slurry is derived from an anaerobic fermentation system using chicken manure as raw material. The specific preparation process includes:

[0040] ① Add chicken manure and methanogen promoter to the anaerobic activated sludge, control the initial total solid content (TS) to 3-5%, the initial pH value to 7.3-7.8, and carry out anaerobic fermentation at 35±2℃ for about 30 days until the methane content in the system reaches more than 65%, which means that the anaerobic activated sludge is acclimated and the efficient bacterial strains in the system are screened and optimized;

[0041] Among them, anaerobic activated sludge refers to the substance containing anaerobic microorganisms in the anaerobic fermentation tank when livestock and poultry manure is added to the anaerobic fermentation tank for anaerobic digestion reaction. The anaerobic digestion flora in the tank decomposes organic matter to produce biogas, and this substance is called anaerobic activated sludge.

[0042] ② Take out the domesticated anaerobic activated sludge and inoculate it into the chicken manure anaerobic fermentation system. At a temperature of 35±2°C, gradually increase the organic load of the fermentation system (unit: g VS / L·d) in a gradient manner. Each time the running time is increased by 0.5 - 1.0 g VS / L·d for anaerobic fermentation of chicken manure. The methane content during the fermentation process is lower than 55%. Appropriately add a methane production promoter to ensure the stable and efficient operation of the system. In addition, while feeding, discharge to keep the volume of the fermentation system constant. The solids in the discharge are recycled to the tank, and the liquid is used for subsequent leaching.

[0043] Among them, the organic load refers to the amount of feed per day per unit volume of the reactor (measured by the amount of volatile organic matter).

[0044] ③ Filter the material after anaerobic fermentation, take the supernatant, which is the biogas slurry used for leaching vinegar residues, and the filtered solid residue is used as the biogas residue for subsequent aerobic composting. Among them, the bicarbonate alkalinity of the biogas slurry is 8000 - 10000 mg / L, and the pH value is 7.5 - 8.0.

[0045] Among them, by mass, the total solid content (TS) of the chicken manure anaerobic fermentation system is 7 - 8%, and the methane content is 60 - 65%. Since there is no effect of the methane-producing bacteria promoter at this stage, the total solid content (TS) increases while the methane content decreases.

[0046] (2) Aerobic composting treatment

[0047] Take the leached vinegar residues, and mix the leached vinegar residues, biogas residues, and wood chips evenly according to a mass ratio of 0.8 - 1.5:0.5 - 2:0.5 - 2. Control the initial carbon-nitrogen mass ratio of the material to be 21 - 24% by increasing or decreasing the biogas residues and wood chips, and adjust the initial moisture content to 50 - 60% by adding biogas slurry. Continuously introduce air, and the ventilation rate is 0.45 - 0.55 L·(min·kg) -1 , and carry out aerobic composting treatment. And when the temperature of the aerobic composting pile body drops below 50°C, add a decay-promoting bacterium agent accounting for 1 - 2‰ of the pile body mass.

[0048] In the present invention, the decay-promoting bacterium agent is Aspergillus fumigatus, which can degrade cellulose, lignin, etc.

[0049] Example 1

[0050] Take fresh vinegar residues with a pH value of 3.5 - 3.8 and anaerobic digestion biogas slurry made from chicken manure, and mix them at mass ratios of fresh vinegar residues to chicken manure biogas slurry of 2:1, 4:1, 6:1, 8:1, and 10:1 respectively. Then conduct leaching at room temperature for 15 minutes.

[0051] Among them, according to different mixing ratios from low to high, they are respectively denoted as Example 1.1, Example 1.2, Example 1.3, Example 1.4, and Example 1.5.

[0052] After the above treatment, use a pH meter, gas chromatography, alkalinity meter, and spectrophotometer to detect the liquid phase pH value, volatile fatty acid concentration, volatile acid salt alkalinity, and dissolved chemical oxygen demand respectively. The results are shown in the test examples.

[0053] Example 2

[0054] Take the biogas slurry after mixing and leaching with a mass ratio of fresh vinegar residues to chicken manure biogas slurry of 6:1 in Example 1. Specifically, it is 500 mL of biogas slurry, 300 g of chicken manure, and make up the volume to 1 L with water. Place the biogas slurry in the fully automatic methane potential test system II for methane production treatment. The total treatment time is 15 days; before treatment, control the total volume of the raw materials in the anaerobic fermentation system to be 1 L, the inoculated raw material is chicken manure, the TS of the system is 8.2%, and the alkalinity is 8465 mg / L.

[0055] During the above methane production treatment process, record the methane production amount every day and calculate the cumulative methane production amount of the system. The results are shown in the test examples.

[0056] Example 3

[0057] Take the vinegar residues after mixing and leaching with a mass ratio of fresh vinegar residues to chicken manure biogas slurry of 6:1 in Example 1. Mix the above vinegar residues, biogas residues, and wood chips evenly at a mass ratio of 1:1:1. Place the mixed materials in a 50 L aerobic composting device, and control the initial carbon-nitrogen ratio of the materials to be between 21.4 - 23.5%, and adjust the initial moisture content to be between 50% - 60% by adding biogas slurry for aerobic composting treatment.

[0058] During the above aerobic composting process, insert a thermometer into the middle of the compost pile, record the composting temperature every day, and detect the dehydrogenase content during the composting process. The results are shown in the test examples.

[0059] Example 4

[0060] On the basis of the raw materials in Example 3, conduct aerobic composting treatment. And when the composting temperature drops below 50 °C, add 1 - 2‰ of a decay-promoting bacterial agent and continue the aerobic composting treatment.

[0061] After adding the decay-promoting bacterium agent, samples were taken from the middle of the compost pile every 4 days, and the cellulase activity in the compost was detected by ultraviolet spectrophotometry. The results are shown in Test Example.

[0062] Comparative Example 1

[0063] The difference between this comparative example and Example 1 is that the anaerobic digestion biogas slurry with chicken manure as the raw material was replaced with pure water, and they were also mixed at the mass ratios of fresh vinegar residue to pure water of 2:1, 4:1, 6:1, 8:1, and 10:1, respectively.

[0064] Among them, according to different mixing ratios from low to high, they were respectively denoted as Comparative Example 1.1, Comparative Example 1.2, Comparative Example 1.3, Comparative Example 1.4, and Comparative Example 1.5.

[0065] After the above treatment, the liquid-phase pH value, volatile fatty acid concentration, volatile salt alkalinity, and dissolved chemical oxygen demand were detected. The results are shown in Test Example.

[0066] Comparative Example 2

[0067] The difference between this comparative example and Example 2 is that the washed biogas slurry was replaced with the unwashed biogas slurry.

[0068] During the above methane production treatment process, the methane production was recorded every day, and the cumulative methane production of the system was calculated. The results are shown in Test Example.

[0069] Comparative Example 3

[0070] The difference between this comparative example and Example 3 is that the washed vinegar residue was replaced with fresh vinegar residue, and the moisture content of the compost materials was controlled by adding pure water.

[0071] During the above aerobic composting process, the compost temperature was recorded every day, and the dehydrogenase content during the composting process was detected. The results are shown in Test Example.

[0072] Comparative Example 4

[0073] The difference between this comparative example and Example 4 is that no decay-promoting bacterium agent was added.

[0074] Starting from the same time as in Example 4, samples were taken every 4 days to detect the cellulase activity in the compost. The results are shown in Test Example.

[0075] Comparative Example 5

[0076] The difference between this comparative example and Example 4 is that at the beginning of aerobic composting, a decay-promoting bacterium agent was added to the raw materials.

[0077] Starting from the same time as in Example 4, samples were taken every 4 days to detect the cellulase activity in the compost. The results are shown in Test Example.

[0078] Test Example

[0079] (1) Example 1 and Comparative Example 1

[0080] As Figures 1 to 5 shown, in Example 1, as the liquid-solid ratio continuously increased, the pH value of the leaching solution gradually increased, and the volatile acid salt alkalinity first remained flat and then increased. When the liquid-solid ratio increased to 6:1, the volatile acid salt alkalinity showed an inflection point; at the same time, the dissolution amounts of acetic acid, propionic acid, and soluble chemical oxygen demand were all the highest, and the highest dissolution amounts were 10.99 g / kg, 1.21 g / kg, and 36.37 g / kg respectively. According to conversion, the dissolution ratio of organic acids in biogas slurry accounted for 30-40% of the soluble chemical oxygen demand. In Comparative Example 1, as the liquid-solid ratio continuously increased, the pH value of the leaching solution basically remained unchanged, and there was no volatile acid salt alkalinity; at the same time, acetic acid, propionic acid, and soluble chemical oxygen demand continued to increase. When the liquid-solid ratio was 10:1, the maximum concentration of the dissolution amounts was 9.18 g / kg, 0.83 g / kg, and 33.74 g / kg respectively.

[0081] Through the comparison between Example 1 and Comparative Example 1, it can be found that using biogas slurry for leaching in Example 1 can significantly increase the final dissolution amount of acids, etc. This is because the biogas slurry itself is slightly alkaline and contains a large amount of buffer substances. As the liquid-solid ratio increases, the content of buffer substances in the biogas slurry becomes more, and a large amount of dissolved organic acids are neutralized. And when the liquid-solid ratio increases to 6:1, almost all the organic acids in the leaching solution are neutralized by the buffer substances, reaching the best level. Therefore, the present invention can effectively separate the organic acids on the surface of fresh vinegar residue, and at the same time, the biogas slurry can adhere to the surface of the vinegar residue, effectively changing the high-acid characteristics of the fresh vinegar residue.

[0082] (2) Example 2 and Comparative Example 2

[0083] As Figure 6 shown, on the 15th day of anaerobic fermentation, the cumulative methane production of the leached biogas slurry was 1156 ml, while the cumulative methane production of the biogas slurry without leached vinegar residue was only 463 ml. It can be seen that the leached biogas slurry, due to dissolving the organic acids and some soluble organic matters attached to the surface of the vinegar residue, the dissolved substances are converted into methane during the anaerobic digestion process. Therefore, the biogas slurry after leaching the vinegar residue proposed by the present invention has strong methane production potential, and can realize the resource utilization of the leached biogas slurry.

[0084] (3) Example 3 and Comparative Example 3

[0085] As Figure 7 shown, through comparison, it can be found that in Example 3, using the leached vinegar residue, the high-temperature period is reached faster during the composting process, and the high-temperature period lasts longer. The main reason is that the fresh vinegar residue has a high acidity, and the adaptability of microorganisms in the compost pile is poor, resulting in problems such as slow start of composting and short high-temperature cycle of composting.

[0086] like Figure 8 As shown, the dehydrogenase activity of Example 3 and Comparative Example 3 increases rapidly during the high temperature period. This is mainly due to the active microorganisms, which secrete a large amount of dehydrogenase to degrade the organic matter in the material to provide the energy required for their own growth and reproduction. Both Example 3 and Comparative Example 3 reached the peak of enzyme activity on the 12th day of composting, but the dehydrogenase activity of Example 3 was 245 μg / (g·h), while the dehydrogenase activity of Comparative Example 3 was only 121 μg / (g·h). Although the dehydrogenase activity of Example 3 showed a significant downward trend in the later stage of composting, and the enzyme activity was significantly lower than that of Comparative Example 3 at the end of composting, this was because some organic matter still existed in the compost of Comparative Example 3 and was not completely degraded, proving that soaking vinegar lees is more conducive to the transformation and degradation of organic matter during the composting process.

[0087] In summary, the pH value of the vinegar dregs after being soaked in biogas slurry in the present invention is increased, and the organic acid on the surface is reduced. At the same time, as the washed vinegar dregs enter the aerobic composting device, the biogas slurry remaining on their surface provides some buffer substances and nutrients, such as amino acids and organic nitrogen, for the compost pile, which not only solves the inhibitory effect caused by high acidity, but also provides more nutrients to the compost pile.

[0088] (4) Example 4 and Comparative Examples 4-5

[0089] like Figures 9 to 10 As shown, in Example 4, after adding 1-2‰ of the pro-rotting bacteria agent on the 9th day of composting, the temperature was maintained above 40°C until the 14th day, and the maximum temperature could reach 48°C; while the temperature in Comparative Example 4 continued to decrease, and by the 14th day, it had dropped to below 35°C; Comparative Example 5 also added 1-2‰ of the pro-rotting bacteria agent at the early stage of composting, but the overall temperature was not much different from that of Comparative Example 4, that is, the addition of the bacteria agent did not play a role in increasing the temperature of the compost.

[0090] At the same time, by testing the cellulase activity, the cellulase activity of the pile in Example 4 reached a peak of 2.54 mg·g on the 12th day. -1 ·d -1 In comparative example 4, the cellulase activity in the pile was reduced to 1.00 mg·g -1 ·d -1 In the following, the cellulase activity of Comparative Example 5 was slightly higher than that of Example 4 and Comparative Example 4 in the initial stage due to the addition of the bacterial agent at the beginning, but the overall maximum cellulase activity was only 1.67 mg·g -1 ·d -1 .

[0091] This proves that adding the decay-promoting bacterium agent when the temperature is below 50°C can effectively maintain the temperature of the compost pile, increase the cellulase activity, and at the same time promote the conversion of organic matter into humic acid substances. This is because the degradation of cellulose in the composting process generally occurs in the mesophilic stage, that is, below 50°C, which can better ensure the high activity of the bacterial community. Therefore, by adding the decay-promoting bacterium agent at a specific temperature, the present invention can effectively increase the cellulase activity, promote the conversion of cellulose into humic acid substances, effectively accelerate the start of composting, and shorten the composting cycle.

[0092] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A method for promoting the humification of vinegar residue, characterized in that, It includes the following steps: S1: Producing biogas slurry: Anaerobic fermentation is carried out using chicken manure, and after filtration, the obtained clear liquid is biogas slurry, and the obtained solid residue is biogas residue; S2: Pretreating vinegar residue: Fresh vinegar residue is leached with biogas slurry and then filtered to obtain leached vinegar residue; S3: Conducting aerobic composting treatment: The leached vinegar residue is mixed with biogas residue and sawdust, and aerobic composting treatment is carried out to obtain vinegar residue compost.

2. The method for promoting the humification of vinegar residue according to claim 1, wherein In step S1, by mass, the total solid content after anaerobic fermentation is 7 - 8%, and the methane content is 60 - 65%.

3. The method for promoting the humification of vinegar residue according to claim 1, characterized in that, In step S1, for the biogas slurry obtained by filtration, its bicarbonate alkalinity is 8000 - 10000 mg / L, and the pH value is 7.5 - 8.

0.

4. The method for promoting the humification of vinegar residue according to claim 1, wherein, In step S2, the volume ratio of fresh vinegar residue to biogas slurry is 6 - 8:1, and the leaching time is 15 - 20 min.

5. The method for promoting the humification of vinegar residue according to claim 1, characterized in that, In step S3, the mass ratio of leached vinegar residue, biogas residue, and sawdust is 0.8 - 1.5:0.5 - 2:0.5 - 2.

6. The method for promoting the humification of vinegar residue according to claim 5, characterized in that, Control the mass ratio of carbon to nitrogen of the material after mixing the leached vinegar residue, biogas residue, and sawdust to be 21 - 24%, and the water content to be 50 - 60%.

7. The method for promoting the humification of vinegar residue according to claim 1, wherein In step S3, during the aerobic composting process, air is continuously introduced at a rate of 0.45 - 0.55 L·(min·kg) -1 ​ 8. The method for promoting the humification of vinegar residue according to claim 1, wherein In step S3, when the temperature of the aerobic composting pile body drops below 50 °C, a rot-promoting bactericide is added.

9. The method for promoting the humification of vinegar residue according to claim 8, wherein, The rot-promoting bactericide includes Aspergillus fumigatus, and the addition amount of the rot-promoting bactericide is 1 - 2‰ of the mass of the pile body.

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