A method for treating agricultural and forestry wastes by using microbial fermentation

Abstract

The invention discloses a method for treating agricultural and forestry wastes by using microbial fermentation, which belongs to the technical field of agricultural and forestry waste treatment, and comprises the following preparation steps: (1) collecting agricultural and forestry wastes and crushing them; (2) mixing the crushed materials with water to obtain a material mixture, adjusting the material mixture to alkalinity, adding sodium hydroxide and sodium polysulfide, and stirring for 1-2 hours; (3) adding fermentation bacteria agent and water, mixing them evenly, and then making a pile for fermentation to obtain fermented waste fertilizer, so as to solve the problems of inconsistent fermentation time, incomplete fermentation, and difficulty in mixed fermentation in the current agricultural and forestry waste fermentation process.

Description

Technical Field

[0001] The invention relates to the technical field of agricultural and forestry waste treatment, and in particular to a method for treating agricultural and forestry waste by using microbial fermentation. Background Art

[0002] Fermentation of agricultural and forestry waste is a process of using microorganisms to decompose and transform agricultural and forestry waste. Through fermentation, organic matter in the waste can be decomposed by microorganisms into organic fertilizer or produce other useful products. At present, the common methods of fermentation of agricultural and forestry waste are: composting, piling agricultural and forestry waste and using microorganisms existing in nature for fermentation; aerobic fermentation, by providing sufficient oxygen supply conditions to promote aerobic microorganisms to ferment agricultural and forestry waste; anaerobic fermentation, under anaerobic conditions, using anaerobic microorganisms to ferment agricultural and forestry waste into biogas or organic fertilizer; fermentation with added strains, during the fermentation process, specific microbial strains can be added to accelerate the decomposition and transformation of waste.

[0003] Agricultural and forestry wastes include agricultural wastes such as common straw, rice husks, edible fungus substrates, etc., and forestry wastes such as branches, trunks, twigs, bark, etc. These raw materials contain a large amount of cellulose, hemicellulose, lignin, etc., and in terms of difficulty, lignin is the most difficult to decompose, crude fat and carbohydrates are easy to decompose, and branches, trunks, twigs, etc. in forestry wastes contain more lignin and hemicellulose, and the mixed fermentation time with agricultural waste is quite different. The speed and degree of decomposition during the fermentation process are different, resulting in possible imbalance in the nutrients in the final fertilizer and inconsistent fermentation time. The fermentation products also need to be decomposed by microorganisms for the second time and released to plants after soil animal activities, resulting in slow onset time and the problem of microorganisms and pathogens infecting crops. Therefore, it is difficult to promote the use of agricultural and forestry wastes after fermentation.

[0004] At present, the fermentation time is long and inconsistent, and the solution to the treatment of microorganisms and pathogens is to use the same waste for fermentation treatment. However, this method is difficult to implement in practice and it is difficult to form large-scale agricultural and forestry waste treatment. Pathogenic bacteria or miscellaneous bacteria are mainly treated by high-temperature fermentation or the use of fungicides. However, the temperature of high-temperature fermentation is difficult to control, and the fermentation pile structure and ventilation, humidity and other conditions need to be adjusted frequently. Fungicides can also cause the death of beneficial bacteria and fermentation microorganisms. Therefore, it is urgent to find a new method of microbial fermentation to treat agricultural and forestry wastes, which will help to achieve truly green utilization of agricultural and forestry wastes. Summary of the invention

[0005] In view of this, the purpose of the present invention is to provide a method for treating agricultural and forestry wastes by using microbial fermentation, so as to solve the problems of inconsistent fermentation time, incomplete fermentation and difficulty in mixed fermentation in the current agricultural and forestry waste fermentation process.

[0006] When agricultural and forestry wastes are mixed and fermented to make fertilizers, the fermentation time of the wastes is uneven due to the different contents of cellulose, hemicellulose and lignin. If the wastes are fully fermented according to the longest time, a large number of metabolites that are beneficial to plant growth and absorption will lose their functions, and miscellaneous bacteria will multiply to become dominant species, causing the plants to become sick. Therefore, the present invention uses the following method to treat agricultural and forestry wastes, which specifically includes the following preparation steps:

[0007] (1) collecting agricultural and forestry waste and crushing it to obtain crushed materials for standby use;

[0008] (2) Mixing the crushed material with water to obtain a material mixture, adjusting the material mixture to alkalinity, stirring at room temperature for 6-8 hours, then adding a 5wt% sodium hydroxide solution at a temperature of 60-80°C, standing for 5-6 hours, adding sodium polysulfide, stirring for 1-2 hours, filtering, and taking out the filter residue for standby use;

[0009] (3) Add fermentation bacteria and water to the removed filter residue, mix well and make a pile for fermentation. When the fermentation temperature is lower than 60°C, add glucuronic acid to the pile, stir well and continue fermentation. When the temperature of the fermentation pile is lower than 55°C, turn the pile every 4-5 days, and sprinkle formaldehyde solution during the turning process. When the temperature of the fermentation pile is lower than 30°C, stop turning the pile and naturally pile it for 7 days to obtain a fermented waste fertilizer.

[0010] The treatment method of the present invention is mainly used for fermentation of agricultural and forestry wastes, such as straw, rice husks, edible fungus substrates, scraps, peanut shells and other wastes. It can also be applied to pruned branches, trunks, twigs, firewood, bark, industrial waste branches, curled skins, shavings and other difficult-to-treat agricultural and forestry wastes. The treatment method of the present invention can especially be used for unified mixed fermentation of agricultural or forestry wastes of different types or with large differences, which can save time and expand the types of raw materials to be processed.

[0011] The agricultural and forestry waste is crushed into fine materials with a size of 0.5-10cm, and then water is added to adjust the pH to be alkaline to dissolve hemicellulose or lignin as much as possible, reducing the proportion of lignin in the high-cellulose material, and then hot sodium hydroxide solution is added to continue to separate and dissolve more lignin. After a certain reaction time, sodium polysulfide is added to form alkaline stable sugar and acid ends inside the material, limiting the dissolution and leaching of lignin in the material, preventing the insufficient nutrient content in the fertilizer due to excessive loss of cellulose, lignin and other substances, and preventing the problem of difficult to balance the fermentation time due to excessive treatment of high-lignin materials. At this time, the lignin content in the forestry waste in the waste materials is greatly reduced. After adding the fermentation agent, a fermentation pile is made. The fermentation temperature continues to rise, and the maximum temperature reaches about 75°C. When the fermentation temperature drops to 60°C, glucuronic acid is added, and then the fermentation continues. When the temperature is lower than 55°C, formaldehyde solution is sprinkled to catalyze the decomposition of the phenylpropane structural units in the lignin, enabling the microbial flora to quickly use the lignin to decompose it into nutrients for direct absorption by plants, while accelerating the fermentation process and shortening the fermentation time.

[0012] Furthermore, in step (2), the pH of the material mixture is adjusted to 9-10.

[0013] Furthermore, in the step (2), the mass ratio of the material mixture to the sodium hydroxide solution is 1:(1-2).

[0014] Furthermore, the mass ratio of the sodium polysulfide added in the step (2) to the crushed material is (0.02-0.05):1.

[0015] Furthermore, in step (3), the mass ratio of the fermentation bacteria agent to the filter residue is (0.1-1):100.

[0016] The strains of the fermented microbial agent are Bacillus subtilis: Pseudomonas aeruginosa: Aspergillus niger: cellulose decomposing bacteria, with a mass ratio of 2:1:2:1:2. The effective live bacteria count is ≥ 200 million / g. When inoculating, it can be weighed and diluted 100 times for use.

[0017] Furthermore, in the step (3), the mass ratio of glucuronic acid to filter residue is (0.05-0.08):1.

[0018] Furthermore, the concentration of the formaldehyde solution in step (3) is 0.1-0.5%, and the mass ratio of the formaldehyde solution to the filter residue is (0.02-0.04): 1. The concentration and amount of formaldehyde need to be strictly controlled to prevent the impact on microorganisms and the harm to plant growth.

[0019] Furthermore, during the fermentation process in step (3), the moisture content of the fermentation pile is maintained at 65-70%.

[0020] Furthermore, the number of times of spraying the methanol solution in step (3) does not exceed 4 times.

[0021] Furthermore, the method is applicable to the fermentation of agricultural waste, forestry waste or mixed fermentation of agricultural and forestry waste, that is, it is applicable to mixed fermentation of wastes with a carbon-nitrogen ratio greater than (25-30):1 or a large difference in carbon-nitrogen ratio.

[0022] Beneficial effects:

[0023] 1. The present invention adjusts the degradation rate of lignin, balances the fermentation time and fermentation progress between different wastes, saves fermentation time and ensures fermentation efficiency, removes plant toxicity generated during the fermentation process, and ensures fertilizer safety.

[0024] 2. The method of the present invention can be applied to the fermentation of wastes with a high carbon-nitrogen ratio, and can also be used for the mixed fermentation of agricultural or forestry wastes with a large carbon-nitrogen ratio difference. The fermentation time is significantly shortened, and the fertilizer obtained by fermentation has a higher fertility, which solves the difficulties of current mixed fermentation of agriculture and forestry. At the same time, the forestry wastes that are difficult to ferment, such as sawdust, branches, and trunks, are also reasonably utilized.

[0025] 3. The present invention utilizes the fermentation of microorganisms to render the agricultural and forestry waste harmless and convert it into high-quality organic fertilizer for agricultural development. The agricultural and forestry waste is recycled and utilized, which greatly improves the utilization rate and added value of waste resources and reduces environmental pollution.

[0026] Instruction Manual

[0027] Figure 1 : Fermentation diagram of Example 3 during 25 days of fermentation;

[0028] Figure 2 : Fermentation diagram of comparative example 1 when fermented for 25 days;

[0029] Figure 3 : Fermentation diagram of comparative example 4 during fermentation for 25 days

[0030] Figure 4 : Fermentation diagram of comparative example 5 when fermented for 25 days DETAILED DESCRIPTION

[0031] The present invention will be described in detail below with reference to the embodiments and accompanying drawings:

[0032] The strains of the fermentation agent are common waste fermentation strains on the market. The strain mass ratio of the strains in this embodiment is 2:1:2:1:2 of Bacillus subtilis: Pseudomonas aeruginosa: Aspergillus niger: cellulose decomposing bacteria, and the effective viable count is ≥ 200 million / g. When inoculating, it can be weighed and diluted 100 times for use.

[0033] Example 1: Fermentation of agricultural waste

[0034] (1) Waste treatment: Wheat straw was collected as waste for fermentation, and the straw was crushed into crushed materials with a diameter of about 0.5-10 cm, and 100 kg was weighed for standby use;

[0035] (2) Mixing the crushed material with water to obtain a material mixture, wherein the optimal water content of the material mixture is about 10%, adjusting the material mixture to an alkaline pH of 9, stirring at room temperature for 6 hours, then adding 100 kg of a 5 wt % sodium hydroxide solution at 60° C., standing for 6 hours, adding 2 kg of sodium polysulfide, stirring for 2 hours, filtering, and taking out the filter residue for standby use;

[0036] (3) 0.1 kg of fermentation bacteria and water are added to 100 kg of filter residue, and the mixture is mixed to form a fermentation pile with a moisture content of about 65% for fermentation. When the fermentation temperature is lower than 60° C. (about the 6th day of fermentation), 5 kg of glucuronic acid is added to the pile, and the fermentation is continued after stirring evenly. When the temperature of the fermentation pile is lower than 55° C. (about the 10th day of fermentation), the pile is turned every 4 days, and 2 kg of formaldehyde solution with a concentration of 0.1 wt% is sprinkled during the turning process. When the temperature of the fermentation pile is lower than 30° C. (about the 18th day of fermentation), the turning of the pile is stopped, and the pile is naturally stacked for 7 days to obtain a fermented waste fertilizer.

[0037] Example 2: Fermentation of forestry waste

[0038] (1) Waste treatment: Collect sawdust as waste for fermentation, crush the sawdust into crushed materials with a diameter of about 0.5-10 cm, and weigh 100 kg for standby use;

[0039] (2) Mixing the crushed material with water to obtain a material mixture, wherein the optimal water content of the material mixture is about 15%, adjusting the material mixture to an alkaline pH of 10, stirring at room temperature for 8 hours, then adding 200 kg of a 5 wt% sodium hydroxide solution at 80° C., standing for 6 hours, adding 5 kg of sodium polysulfide, stirring for 2 hours, filtering, and taking out the filter residue for standby use;

[0040] (3) 100 kg of filter residue is added with 1 kg of fermentation agent and water, and the mixture is evenly mixed to form a fermentation pile with a water content of about 70% for fermentation. When the fermentation temperature is lower than 60° C. (about the 8th day of fermentation), 8 kg of glucuronic acid is added to the pile, and the fermentation is continued after being evenly stirred. When the temperature of the fermentation pile is lower than 55° C. (about the 13th day of fermentation), the pile is turned every 5 days, and 4 kg of formaldehyde solution with a concentration of 0.5 wt% is sprinkled during the turning process. When the temperature of the fermentation pile is lower than 30° C. (about the 22nd day of fermentation), the turning of the pile is stopped, and the pile is naturally stacked for 7 days to obtain a fermented waste fertilizer.

[0041] Example 3: Fermentation of agricultural and forestry waste

[0042] (1) Waste treatment: Sawdust and wheat straw were collected as waste in a mass ratio of 1:1 for fermentation, and the straw was crushed into crushed materials with a diameter of about 0.5-10 cm, and 100 kg was weighed for standby use;

[0043] (2) Mixing the crushed material with water to obtain a material mixture, wherein the optimal water content of the material mixture is about 12%. Adjusting the material mixture to an alkaline pH of 9, stirring at room temperature for 7 hours, then adding 150 kg of a 5 wt % sodium hydroxide solution at 70° C., standing for 6 hours, adding 3 kg of sodium polysulfide, stirring for 2 hours, filtering, and taking out the filter residue for standby use;

[0044] (3) 0.5 kg of fermentation bacteria and water are added to 100 kg of filter residue, and the mixture is uniformly mixed to form a fermentation pile with a moisture content of about 68% for fermentation. The pile is 2 m wide, 1 m high and 5 m long. When the fermentation temperature is lower than 60° C. (about the 7th day of fermentation), 6 kg of glucuronic acid is added to the pile, and the fermentation is continued after being uniformly stirred. When the temperature of the fermentation pile is lower than 55° C. (about the 11th day of fermentation), the pile is turned every 4 days, and 3 kg of formaldehyde solution with a concentration of 0.3 wt% is sprinkled during the turning process. When the temperature of the fermentation pile is lower than 30° C. (about the 18th day of fermentation), the turning of the pile is stopped, and the pile is naturally stacked for 7 days to obtain a waste fertilizer that has been fermented.

[0045] The following comparative examples are compared with Example 3:

[0046] Comparative Example 1:

[0047] This comparative example is a comparative example of Example 3. The difference from Example 3 is that microbial fermentation is directly adopted in the fermentation process. The specific fermentation process is as follows:

[0048] (1) Weigh 100 kg of the crushed material of Example 3 and mix it with water to adjust the moisture content to 68%, add 0.5 kg of fermentation agent, turn the pile once every 4 days, and stop turning the pile when the fermentation pile temperature is lower than 30° C., and naturally stack it until waste fertilizer is obtained.

[0049] Comparative Example 2:

[0050] This comparative example is a comparative example of Example 3. The difference from Example 3 is that sodium hydroxide and microorganisms are directly used for fermentation during the fermentation process. The specific fermentation process is as follows:

[0051] (1) Weigh 100 kg of the crushed material of Example 3 and mix it with water to adjust the water content to 12% and pH to 9. After stirring at room temperature for 7 hours, add 150 kg of 5 wt% sodium hydroxide solution at 70° C., let it stand for 6 hours, and then take out the filter residue for use;

[0052] (2) Add 0.5 kg of fermentation agent and water to 100 kg of filter residue, mix well to form a fermentation pile with a moisture content of about 68%, and turn the pile every 4 days. When the temperature of the fermentation pile is lower than 30° C., stop turning the pile and let it naturally pile up until waste fertilizer is obtained.

[0053] Comparative Example 3:

[0054] This comparative example is a comparative example of Example 3, and the difference from Example 3 is that sodium polysulfide is not used in the fermentation process. The specific fermentation process is as follows:

[0055] (1) Waste treatment: collect branches and wheat straw as waste in a mass ratio of 1:1 for fermentation, crush the straw into crushed materials with a diameter of about 0.5-10 cm, and weigh 100 kg for standby use;

[0056] (2) Mixing the crushed material with water to obtain a material mixture, wherein the optimal water content of the material mixture is about 12%, adjusting the material mixture to an alkaline pH of 9, stirring at room temperature for 7 hours, then adding 150 kg of a 5 wt % sodium hydroxide solution at 70° C., standing for 8 hours, and filtering to remove the filter residue for standby use;

[0057] The subsequent operations are the same.

[0058] Comparative Example 4:

[0059] This comparative example is a comparative example of Example 3. The difference from Example 3 is that glucuronic acid is not used in the fermentation process. The specific fermentation process is as follows:

[0060] (1) Waste treatment: collect branches and wheat straw as waste in a mass ratio of 1:1 for fermentation, crush the straw into crushed materials with a diameter of about 0.5-10 cm, and weigh 100 kg for standby use;

[0061] (2) Mixing the crushed material with water to obtain a material mixture, wherein the optimal water content of the material mixture is about 12%. Adjusting the material mixture to an alkaline pH of 9, stirring at room temperature for 7 hours, then adding 150 kg of a 5 wt % sodium hydroxide solution at 70° C., standing for 6 hours, adding 3 kg of sodium polysulfide, stirring for 2 hours, filtering, and taking out the filter residue for standby use;

[0062] (3) adding 0.5 kg of fermentation bacteria and water to 100 kg of filter residue, mixing evenly to form a fermentation pile with a moisture content of about 68% for fermentation. When the temperature of the fermentation pile is lower than 55° C., turning the pile every 5 days, and sprinkling 3 kg of formaldehyde solution with a concentration of 0.3 wt % during the turning process. When the temperature of the fermentation pile is lower than 30° C., turning the pile is stopped and the pile is naturally stacked until waste fertilizer is obtained.

[0063] Comparative Example 5:

[0064] This comparative example is a comparative example of Example 3. The difference from Example 3 is that no formaldehyde solution is used during the fermentation process. The specific fermentation process is as follows:

[0065] (1) Waste treatment: collect branches and wheat straw as waste in a mass ratio of 1:1 for fermentation, crush the straw into crushed materials with a diameter of about 0.5-10 cm, and weigh 100 kg for standby use;

[0066] (2) Mixing the crushed material with water to obtain a material mixture, wherein the optimal water content of the material mixture is about 12%. Adjusting the material mixture to an alkaline pH of 9, stirring at room temperature for 7 hours, then adding 150 kg of a 5 wt % sodium hydroxide solution at 70° C., standing for 6 hours, adding 3 kg of sodium polysulfide, stirring for 2 hours, filtering, and taking out the filter residue for standby use;

[0067] (3) Add 0.5 kg of fermentation bacteria and water to 100 kg of filter residue, mix well to form a fermentation pile with a moisture content of about 68% for fermentation. When the fermentation temperature is lower than 60° C., add 6 kg of glucuronic acid to the pile, stir well and continue fermentation. Turn the pile every 5 days. When the temperature of the fermentation pile is lower than 30° C., stop turning the pile and naturally stack it until waste fertilizer is obtained.

[0068] Comparative Example 6:

[0069] This comparative example is a comparative example of Example 3. The difference from Example 3 is that glucuronic acid and formaldehyde solution are directly added at one time during the fermentation process, and are not added according to the temperature. The specific fermentation process is as follows:

[0070] (1) Waste treatment: collect branches and wheat straw as waste in a mass ratio of 1:1 for fermentation, crush the straw into crushed materials with a diameter of about 0.5-10 cm, and weigh 100 kg for standby use;

[0071] (2) Mixing the crushed material with water to obtain a material mixture, wherein the optimal water content of the material mixture is about 12%. Adjusting the material mixture to an alkaline pH of 9, stirring at room temperature for 7 hours, then adding 150 kg of a 5 wt % sodium hydroxide solution at 70° C., standing for 6 hours, adding 3 kg of sodium polysulfide, stirring for 2 hours, filtering, and taking out the filter residue for standby use;

[0072] (3) Add 0.5 kg of fermentation bacteria and water to 100 kg of filter residue, mix well to form a fermentation pile with a water content of about 68% for fermentation. When the fermentation temperature is lower than 60° C., add 6 kg of glucuronic acid and 3 kg of formaldehyde solution with a concentration of 0.3 wt %. After stirring evenly, turn the pile every 5 days. When the temperature of the fermentation pile is lower than 30° C., stop turning the pile and naturally stack it until waste fertilizer is obtained.

[0073] It was measured that the C / N ratio of the fermentation raw material wheat straw was about 58, and the C / N ratio of the sawdust was about 150. The fertilizers prepared in Example 3 and Comparative Examples 1-6 were tested, and the lignin degradation rate, the decrease in volatile solid content, and the total time required for decomposition (seed germination test method) were measured on the 30th day of fermentation. At the same time, the decomposed fertilizer was used for the seed germination experiment, and the specific experimental process was as follows:

[0074] The composts of Example 3 and Comparative Examples 1-6 were air-dried to the same water content, and 2 g of each was weighed and placed in a culture dish. Two filter papers of the same size were placed in the culture dish. 20 mL of distilled water was absorbed in the culture dish, and 30 tomato seeds of the same variety with full grains and no pests were evenly placed. Distilled water was used as a control. Five replicates were made for each group of composts. The time when the germination index was greater than 80% was recorded as the fermentation time. At the same time, the germination index of the 35th seed was recorded. The data obtained are shown in Table 1:

[0075] Table 1

[0076]

[0077] Analysis Table 1 and Figure 1-4 The results:

[0078] 1. The optimal C / N ratio required for the fermentation of agricultural and forestry wastes is (25-30): 1. According to the initial measurement of the C / N ratio, the C / N ratio of the waste selected in the embodiment of the present invention is relatively high. The C / N ratio of wheat straw is about 58, and the C / N ratio of sawdust is about 150. Therefore, the fermentation time of the two wastes is relatively long, and the fermentation time required for sawdust in the raw material is much longer than that of wheat straw. However, from the comparison between Example 3 and Comparative Examples 1-6, the fermentation time of Example 3 is shortened to 25 days, and the fermentation results are as follows: Figure 1 As shown, compared with the result of comparative example 1 using only bacterial fermentation, 20 days are saved. This is because the fermentation method disclosed in the present invention improves the degradation speed and degradation rate of lignin, saves fermentation time, and at the same time, the change in the degree of degradation of organic matter can be further verified by the decrease in volatile solid content, indicating that the preparation method of this embodiment promotes the degradation of volatile solids, is beneficial to accelerate the maturity of compost and improve the quality of compost.

[0079] 2. In addition to the shortened fermentation time, Example 3 also has a higher germination index on the 35th day compared with Comparative Examples 1 and 2. The germination indexes of Comparative Examples 1 and 2 are 59.85% and 65.91%, respectively, which are far lower than 80% (when the GI index is ≥80%, the compost can be considered to be fully decomposed and non-toxic). This indicates that on the 35th day, the composts of Comparative Examples 1 and 2 began to show signs of decomposition, but the degree of decomposition was not high, and the compost may contain phytotoxicity. The results of Comparative Example 1 fermented for 25 days are as follows: Figure 2 As shown, the germination index of Example 3 reached 189.24, indicating that the seeds grew well, the compost was completely decomposed without phytotoxicity, and had good fertility. This shows that only using microbial agents or directly using alkali treatment combined with microbial agent fermentation is difficult to apply to the mixed fermentation and fertilizer production of wastes with high carbon-nitrogen ratios and large carbon-nitrogen ratio differences.

[0080] 3. Compared with Comparative Example 3, Example 3 has a greater decrease in lignin degradation rate and volatile solid content, and the fermentation time is shorter. However, the germination index of Comparative Example 3 is lower. This is because sodium polysulfide has an inhibitory effect, which can retain more nutrients on the basis of balanced fermentation time and promote the increase of fertilizer fertility, so as to prevent the situation in Comparative Example 3 where the fermentation time is shortened but the seed germination effect is poor.

[0081] 4. Compared with Comparative Examples 4-6, Example 3 differs in that glucuronic acid and formaldehyde solution are lacking and glucuronic acid and formaldehyde solution are added at one time. Compared with Example 3, it is known that if glucuronic acid and formaldehyde solution are not used, it is difficult to synergistically degrade lignin, the lignin degradation rate is low, and the fermentation time is prolonged. The fermentation results of Comparative Examples 4 and 6 after 25 days of fermentation are as follows: Figure 3 , 4 As shown, the volatile solid content decreased less and the fertility was poorer, and the fermentation effect of adding glucuronic acid and formaldehyde solution at one time was also worse than that of Example 3.

[0082] The above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the present invention. Although the present invention is described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the purpose and scope of the technical solutions of the present invention, which should be included in the scope of the claims of the present invention. The techniques, shapes, and structural parts not described in detail in the present invention are all known technologies.

Claims

1. A method for treating agricultural and forestry wastes by using microbial fermentation, characterized in that: The method comprises the following preparation steps: (1) Collect agricultural and forestry waste and crush it to obtain crushed materials for standby use; (2) Mix the crushed material with water to obtain a material mixture, adjust the material mixture to alkalinity, stir it at room temperature for 6-8 hours, then add a 5wt% sodium hydroxide solution at a temperature of 60-80°C, let it stand for 5-6 hours, then add sodium polysulfide, stir it for 1-2 hours, filter it, and take out the filter residue for standby use; (3) Adding fermentation bacteria and water to the removed filter residue, mixing evenly and then making a pile for fermentation. When the fermentation temperature is lower than 60°C, adding glucuronic acid to the pile, stirring evenly and then continuing the fermentation. When the temperature of the fermentation pile is lower than 55°C, turning the pile every 4-5 days, and sprinkling formaldehyde solution during the turning process. When the temperature of the fermentation pile is lower than 30°C, stopping turning the pile, and naturally stacking for 7 days to obtain fermented waste fertilizer; The mass ratio of the sodium polysulfide added in step (2) to the crushed material is (0.02-0.05): 1; In the step (3), the mass ratio of glucuronic acid to the filter residue is (0.05-0.08):1; The concentration of the formaldehyde solution in step (3) is 0.1-0.5%, and the mass ratio of the formaldehyde solution to the filter residue is (0.02-0.04):

1.

2. The method for treating agricultural and forestry wastes by using microbial fermentation according to claim 1, characterized in that: In the step (2), the pH of the material mixture is adjusted to 9-10.

3. The method for treating agricultural and forestry wastes by using microbial fermentation according to claim 1, characterized in that: The mass ratio of the material mixture to the sodium hydroxide solution in step (2) is 1:(1-2).

4. The method for treating agricultural and forestry wastes by using microbial fermentation according to claim 3, characterized in that: In step (3), the mass ratio of the fermentation bacteria agent to the filter residue is (0.1-1):

100.

5. The method for treating agricultural and forestry wastes by using microbial fermentation according to claim 4, characterized in that: During the fermentation process in step (3), the moisture content of the fermentation pile is maintained at 65-70%.

6. The method for treating agricultural and forestry wastes by using microbial fermentation according to claim 5, characterized in that: The number of times of spraying the formaldehyde solution in step (3) does not exceed 4 times.

7. A method for treating agricultural and forestry wastes by microbial fermentation according to any one of claims 1 to 6, characterized in that: The method is applicable to the fermentation of agricultural waste, the fermentation of forestry waste or the mixed fermentation of agricultural and forestry waste.

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