Filtered mud composting method based on synergistic interaction of sargassum fusiforme and complex microbial inoculants

Abstract

The invention discloses a bagasse filter mud composting method based on synergistic interaction of sargassum fusiforme and a complex microbial inoculant. The method comprises the following steps: mixing a sugar manufacturing byproduct bagasse and filter mud according to a certain dry weight ratio, and adjusting the moisture and carbon nitrogen ratio; synchronously adding sargassum fusiforme powder and a compound microbial agent, wherein the microbial agent is prepared by compounding bacillus licheniformis and phanerochaete chrysosporium; the high-temperature period is maintained for not less than 7 days, the total fermentation period is about 45 days, and the matured compost and the fertilizer thereof are prepared. The sargassum fusiforme is used as a natural conditioner, so that the composition of nutrient substances can be optimized, nitrogen and water are preserved, and heavy metals are passivated; and the lignocellulose is specifically degraded by the complex microbial inoculants. Through the synergistic effect of the bagasse and the filter mud, the high-temperature period of the compost is remarkably prolonged, the nutrient loss is reduced, the decomposition degree and the environmental safety of a compost product are improved, and an efficient and environment-friendly new way is provided for high-value resource utilization of the bagasse and the filter mud.

Description

Technical Field

[0001] This invention relates to the field of biological solid organic waste resource utilization technology, specifically a method for efficient aerobic composting using sugarcane bagasse and filter mud, byproducts of the sugar industry. Background Technology

[0002] Guangxi is my country's largest sugar production base, accounting for approximately 70% of the national sugarcane output. Sugarcane is a vital pillar industry of Guangxi's economy. During the sugarcane crushing process, each ton of sugarcane produces 3.5% to 4.8% filter mud, averaging about 4.2%. Statistics show that Guangxi produces an average of 56 million tons of raw sugarcane annually, generating approximately 2.352 million tons of filter mud. However, for a long time, filter mud from sulfite-process sugar factories has been indiscriminately discharged, causing serious environmental pollution. The main components of filter mud from sulfite-process sugar factories are various nutrients absorbed by sugarcane from the soil and various organic substances synthesized within the sugarcane, including nitrogen, phosphorus, potassium, and other macro- and micro-elements essential for crop growth. Bagasse itself is rich in cellulose and hemicellulose, with a dense structure, making it the most stable and difficult-to-degrade organic carbon component during composting.

[0003] Therefore, utilizing filter mud and bagasse from sulfite sugar factories to produce humic acid-rich bio-organic fertilizer and promoting its application in agricultural production can solve the environmental pollution problem caused by filter mud from sulfite sugar factories and alleviate the problem of declining soil fertility in agricultural production. This is an effective way to achieve resource utilization and promote the sustainable and healthy development of the sugar industry.

[0004] However, traditional bagasse filter mud co-composting faces the following technical bottlenecks. First, the carbon-to-nitrogen ratio is unbalanced, resulting in slow fermentation initiation. Bagasse has a high C / N ratio, while filter mud has a relatively low C / N ratio. Simply mixing the two can lead to inactive microorganisms, difficulty in raising the compost pile temperature, and a long composting period. Second, lignocellulose degradation is difficult. Bagasse has a high lignocellulose content and complex structure, making it difficult for ordinary indigenous microorganisms to effectively decompose, resulting in insufficient compost maturity. Third, there is the risk of heavy metal bioavailability. Heavy metals such as Cu, Zn, and Cd that may be present in the filter mud, if not effectively fixed during composting, can be introduced into the soil with the fertilizer, posing environmental risks. Fourth, nutrient retention and conversion efficiency is low: during long-term composting, nutrients such as nitrogen are easily lost through volatilization as ammonia, reducing the fertilizer efficiency of the final product.

[0005] While there are reports of adding microbial agents or activators in existing technologies, they often have a single function, either focusing on degrading lignin or on nitrogen retention, resulting in significant room for improvement in composting efficiency and quality.

[0006] Sargassum fusiforme, a nutrient-rich and bioactive seaweed, is abundant in crude protein, total carbohydrates, crude fiber, natural pigments, vitamins, amino acids, and minerals such as calcium, iodine, and selenium. It has potential applications in the food, pharmaceutical, and chemical industries. In the food industry, Sargassum fusiforme is primarily processed into dried, pickled, and ready-to-eat products, largely reliant on exports. Some products only extract specific components as excipients, discarding the algae and other components, resulting in resource waste. In the pharmaceutical field, it can provide active substances or be used in formulations, but there are few deeply developed pharmaceutical products. While the chemical industry utilizes its polysaccharides to make skincare products and alginate to produce daily chemical products, the product range is limited and the industrial scale is small. Overall, the resource utilization rate of Sargassum fusiforme is low; most development only targets certain components, failing to achieve full resource utilization and resulting in the waste of nutrients and resources.

[0007] Although existing technologies document the use of Sargassum fusiforme as a crop fertilizer raw material, such as patent application CN201710927188.8, a method for preparing seaweed fertilizer using Sargassum fusiforme as a raw material; and patent application CN201110252719.0, a method for preparing compound microbial liquid fertilizer, in which Sargassum fusiforme is crushed or enzymatically hydrolyzed and used as fertilizer, there is little documented in existing literature on how to use Sargassum fusiforme as an additive in high-temperature composting to improve composting efficiency and the degree of compost maturation. Summary of the Invention

[0008] The purpose of this invention is to overcome the shortcomings of the prior art and provide an efficient and environmentally friendly method for composting bagasse filter mud. Through the synergistic effect of Sargassum fusiforme and compound microbial agents, the composting process can be started up quickly, deeply decomposed, and efficiently retained in nutrients.

[0009] To achieve the above objectives, the present invention adopts the following technical solution: The present invention discloses a method for composting bagasse filter mud based on the synergistic effect of Sargassum fusiforme and compound microbial agents, comprising the following steps: (1) Raw material pretreatment: Mix bagasse with filter mud and adjust the moisture and carbon-nitrogen ratio; (2) Selection of additives: Sargassum powder and compound microbial agent are added to the mixture of bagasse and filter mud at the same time. The amount of Sargassum powder added is 4% to 6% of the total wet weight of the compost material, and the amount of compound microbial agent added is 4% to 6% of the total wet weight of the compost material. The compound microbial agent contains Bacillus licheniformis and Protozoa chrysospora, which are compounded according to a certain ratio of live bacteria. (3) Composting fermentation: After the composting raw materials are mixed evenly, the pile is built for aerobic fermentation. The pile is turned over regularly to promote aeration and uniform fermentation. (4) Composting and aging: When the temperature of the pile naturally drops to the ambient temperature and the material has no odor and is dark brown and loose, age it for 10 days to obtain composted fertilizer. (5) Method for making compost: Dry the compost in a cool and ventilated place until the moisture content is reduced to 20% to make solid fertilizer.

[0010] The dry weight mixing ratio of bagasse and filter mud in the raw material pretreatment is (1:1) to (3:2).

[0011] The carbon-to-nitrogen ratio (C / N) of the bagasse-filter mud mixture in the raw material pretreatment is 28:1, and the water content of the bagasse-filter mud mixture is 60%.

[0012] In the selection of the additive, the ratio of viable bacteria of Bacillus licheniformis to Phanerochaete chrysosporium is (1:1) to (2:1), and the concentration is 1*10. 8 CFU / mL.

[0013] The composting fermentation process is aerobic fermentation, and the temperature of the compost pile is controlled at 55-65℃ during the high-temperature fermentation stage.

[0014] Preferably, the amount of Sargassum fusiforme powder added is 5% of the total wet weight.

[0015] The method for preparing the Sargassum fusiforme powder is as follows: (1) Pretreatment: Rinse fresh, mold-free Sargassum seaweed 3-5 times with clean water to remove impurities such as mud and sand attached to the surface, and drain the surface water; (2) Desalination: (a) Cut the pretreated Sargassum fusiforme into 2-3 cm pieces and add deionized water at a solid-liquid ratio of 1:10; (b) Soak at room temperature (25°C) for 3 hours, stirring once every hour for about 1 minute each time; (c) After soaking for 3 hours, replace with deionized water and repeat the soaking process 2-3 times, for a total soaking time of 6-9 hours; (d) After soaking, rinse quickly 2-3 times with deionized water and drain. (e) Take the supernatant after the last soaking and measure its conductivity using a conductivity meter. When EC ≤ 500 μS / cm, it indicates that the desalination standard has been met; (3) Drying: Spread the desalted Sargassum evenly on a tray, controlling the thickness to 1-2 cm. Set the oven drying temperature to 55℃ and dry with forced air for 12-16 hours until constant weight is achieved. After drying, remove and place in a desiccator to cool to room temperature; (4) Crushing and sieving: The dried seaweed is put into a crusher for crushing. After crushing, it is passed through a 60-mesh sieve to obtain seaweed powder. It is then sealed and stored in a dry and cool place.

[0016] Compared with the prior art, the beneficial effects of the present invention are: 1. Regarding the composting process of this invention, Sargassum fusiforme itself is rich in nitrogen, phosphorus, potassium, and seaweed polysaccharides, which can provide readily available nutrients for the microbial community in the compost and accelerate the fermentation process. Algal polysaccharides (such as alginate and carrageenan) produce reducing sugars, phenols, and quinones through degradation. These compounds can form humic acid and fulvic acid through the Maillard reaction and phenol-quinone polymerization, providing humic precursors for compost fermentation. The sodium alginate and other polysaccharides in Sargassum fusiforme have excellent film-forming and water-absorbing properties, enabling them to adsorb and fix ammonium nitrogen, significantly reducing nitrogen volatilization in the form of ammonia, and acting as a natural nitrogen retainer.

[0017] 2. The alginate, fucoidan, and cellulose in the cell walls of Sargassum fusiforme contain a large number of functional groups such as -COOH, -OH, and -SO3H. These are active sites for strongly complexing and adsorbing heavy metal ions (such as Cd²⁺, Pb²⁺, Cu²⁺, and Zn²⁺). They can fix heavy metals through ion exchange, effectively reducing the available heavy metal content in compost products and improving environmental safety. The composting fermentation process can transform easily decomposable organic matter in Sargassum fusiforme into more stable humus. Humus (especially humic acid) is itself an excellent heavy metal chelating agent. This process may activate or expose more adsorption sites in Sargassum fusiforme and form a composite passivating material of "humus-Sargassum fusiforme matrix". Functional microorganisms in the compost may further enhance this process through biosorption and transformation (such as reducing Cr). 6 Mechanisms such as ⁺ (Cr³⁺) further contribute to the fixation of heavy metals.

[0018] 3. The compound microbial inoculant played a targeted degradation role. Among them, *Phanerochaete chrysosporium*, as the model species of white-rot fungi, can secrete powerful lignin peroxidase and manganese peroxidase, which preferentially degrade the complex lignin structure in bagasse, break the lignin's encapsulation of cellulose and hemicellulose, and effectively degrade lignocellulose; *Bacillus licheniformis* can rapidly utilize easily degradable organic matter to generate heat, promote rapid temperature rise of the pile, and at the same time secrete cellulase to effectively decompose cellulose, forming a functional complementarity with the fungi to jointly promote the maturation of the material.

[0019] 4. The combined use of Sargassum fusiforme and compound microbial agents produced a significant synergistic effect. Sargassum fusiforme provides superior nutrition and a favorable microenvironment for rapid microbial proliferation, while the efficient degradation by the compound microbial agents promotes the release and transformation of nutrients in Sargassum fusiforme itself. The two mutually promote each other, jointly achieving the effects of rapidly initiating composting fermentation, deeply degrading lignocellulose, efficiently retaining nutrients, and safely passivating heavy metals. Experiments have shown that compared with treatment groups that did not add any substances, only added Sargassum fusiforme, or only added microbial agents, the thermophilic period of the treatment group of this invention was effectively extended to day 11, and the seed germination index was significantly improved.

[0020] 5. Furthermore, this invention uses filter mud and bagasse from the sugar industry as raw materials, and produces a humus-rich bio-organic fertilizer through aerobic fermentation. This achieves the resource utilization of filter mud, solving the pollution problem of sugar mill filter mud, enhancing soil fertility, and promoting the sustainable and healthy development of the sugar industry. Practical application shows that using the organic fertilizer produced by this invention in the cultivation of Shandong No. 4 cabbage can improve the soil's fertilizer retention and water storage capacity, and significantly promote the germination rate and root development of the cabbage. Attached Figure Description

[0022] Figure 1 These are the temperature change curves of the CK group, S group, MI group, and SMI group during the composting process; The SMI group rapidly increased its temperature to above 55°C within 24 hours, and the high-temperature period lasted for 11 days, significantly longer than the CK, S, and MI groups.

[0023] Figure 2 This is a comparison of the seed germination index (GI) of the products from the CK group, S group, MI group, and SMI group after composting. The seed germination index (GI) of the SMI group samples reached 134.96%, indicating that the compost was basically decomposed and the toxic substances were basically completely degraded. The compost contained nutrients that were beneficial to seed germination (such as humus and mineral nutrients), so the germination index remained stable at a high value, indicating that the compost had a certain promoting effect on seed germination.

[0024] Figure 3 These are the pH change curves of the CK group, S group, MI group, and SMI group during the composting process; Figure 4 These are the conductivity change curves of the CK group, S group, MI group, and SMI group during the composting process. Detailed Implementation

[0025] Source of raw materials 1. Composting raw materials Filter mud and bagasse: Taken from the bagasse filter mud stockpile of Najintian Pitaya Industrial Demonstration Park, Zhenliu Village, Natong Town, Long'an County, Nanning City, Guangxi Zhuang Autonomous Region.

[0026] 2. Microbial strains Bacillus licheniformis and Trichoderma longifolia: purchased from the China Industrial Microbial Culture Collection Center (CICC). *Phanerochaete chrysosporium*: purchased from the American Type Culture Collection (ATCC)

[0027] 3. Additives Rice husk biochar: purchased from Hongsheng Activated Carbon Co., Ltd., Dongguan City, Guangdong Province Sargassum powder: Sargassum samples were purchased from Liu Yan Aquatic Products Store in Dongping, Dongtou, Wenzhou, Zhejiang. Sargassum samples need to undergo the following processing to be made into Sargassum powder.

[0028] (1) Pretreatment: Rinse fresh (moldy) seaweed with clean water 3-5 times to remove impurities such as mud and sand attached to the surface, and drain the surface water; (2) Desalination: (a) Cut the pretreated Sargassum fusiforme into 2-3 cm pieces and add deionized water at a solid-liquid ratio of 1:10; (b) Soak at room temperature (25°C) for 3 hours, stirring once every 1 hour for about 1 minute each time; (c) After soaking for 3 hours, replace with deionized water and repeat the soaking process 2-3 times, for a total soaking time of 6-9 hours; (d) After soaking, rinse quickly 2-3 times with deionized water and drain. (e) Take the supernatant after the last soaking and measure the conductivity with a conductivity meter. When EC ≤ 500 μS / cm, it indicates that the desalination standard has been met.

[0029] (3) Drying: Spread the desalted Sargassum evenly on a tray, with a thickness of 1-2 cm. Set the oven drying temperature to 55℃ and dry with forced air for 12-16 h until constant weight is achieved (the difference in mass between two weighings ≤ 0.2%). After drying, remove the dried seaweed and place it in a desiccator to cool to room temperature.

[0030] (4) Crushing and sieving: The dried seaweed is put into a crusher for crushing. After crushing, it is passed through a 60-mesh sieve to obtain seaweed powder. It is then sealed and stored in a dry and cool place.

[0031] 4. Calculation method (1) Germination index: After mixing the well-rotted compost product with deionized water in a certain proportion, the extract was taken. The seeds of Shandong No. 4 Chinese cabbage were cultured in the extract for 3 days at 28℃, and the germination index of the seeds was measured.

[0032] Germination index = relative germination rate / relative root length (2) Methods for determining the content of humic substances (HS) and humic acid (HA): Accurately weigh 1.00 g of air-dried compost sample, add 40 ml of a mixed solution of 0.1 mol / L NaOH and 0.1 mol / L Na4P2O710H2O (volume ratio 1:1), and shake horizontally at 25℃ and 180 rpm for 24 h. Centrifuge the resulting mixture at 4℃ and 10000 rpm for 15 min, take 1 ml of the supernatant, dilute it 40 times, and filter it through a 0.45 μm filter membrane to obtain the HS sample.

[0033] Adjust the pH of the HS sample to 1 with 6 mol / L HCl, let it stand at room temperature for 12 h to ensure complete precipitation, and centrifuge at 10,000 rpm for 15 min at 4 °C. Take all the precipitate, wash three times with 0.1 mol / L HCl, wash three times with deionized water, and then redissolve it with 0.05 mol / L NaHCO3. Take 1 ml of the completely dissolved solution, dilute it 30 times, and filter it through a 0.45 μm filter membrane to obtain the HA sample.

[0034] The total organic carbon (TOC) content in the diluted solution sample was measured using a total organic carbon analyzer.

[0035] The actual content is calculated using the following formula.

[0036] HS = TOC measured value * V * 40 / m HA = TOC measured value * V * 30 / m Where V is the volume (in L) of the mixed solution of 0.1 mol / L NaOH and 0.1 mol / L Na4P2O710H2O used to extract HS. m is the mass of HS weighed (unit: g); 40 and 30 are dilution factors.

[0037] The present invention will be further described below with reference to embodiments, but the scope of protection of the present invention is not limited thereto.

[0038] Example 1

[0039] CK group: No additives added.

[0040] (1) Raw material pretreatment: Mix bagasse and filter mud at a ratio of 1.42:1, adjust the initial moisture content of the mixture to 60%, and the carbon-nitrogen ratio (C / N) to 28:1; (2) Composting fermentation: After the composting raw materials are mixed evenly, they are piled in a 60L composting bucket for aerobic fermentation. During the high-temperature fermentation stage of composting, the temperature of the pile is controlled at 55-65℃. The pile is turned regularly to promote ventilation and uniform fermentation. (3) Composting and aging: When the temperature of the pile naturally drops to the ambient temperature and the material has no odor and is dark brown and loose, age it for 10 days to obtain composted fertilizer; (4) Method for making compost: Dry the compost in a cool and ventilated place until the moisture content is reduced to 20% to make solid fertilizer.

[0041] The results showed that bagasse filter mud compost without the addition of Sargassum powder and compound microbial agents rapidly heated to above 55°C within 24 hours after pile construction, and the high temperature period lasted for 5 days. After 45 days of fermentation, the humic content was 115.83 mg / g and the humic acid content was 61.04 mg / g.

[0042] Example 2

[0043] Group S: Only 5% of the total wet weight of Sargassum fusiforme powder is added to the additives, and no compound microbial agents are added.

[0044] (1) Raw material pretreatment: Mix bagasse and filter mud at a ratio of 1.42:1, adjust the initial moisture content of the mixture to 60%, and the carbon-nitrogen ratio (C / N) to 28:1; (2) Selection of additives: Add 5% of the total wet weight of Sargassum powder to the mixture of bagasse and filter mud.

[0045] (3) Composting fermentation: After the composting raw materials are mixed evenly, they are piled in a 60L composting bucket for aerobic fermentation. During the high-temperature fermentation stage of composting, the temperature of the pile is controlled at 55-65℃. The pile is turned regularly to promote ventilation and uniform fermentation. (4) Composting and aging: When the temperature of the pile naturally drops to the ambient temperature and the material has no odor and is dark brown and loose, age it for 10 days to obtain composted fertilizer. (5) Method for making compost: Dry the compost in a cool and ventilated place until the moisture content is reduced to 20% to make solid fertilizer.

[0046] The results showed that the compost with only Sargassum powder entered the high-temperature period about 48 hours after pile construction, and the high-temperature period lasted for 8 days. After 45 days of fermentation, the humic content reached 135.95 mg / g (of which the humic acid content was 71.57 mg / g), which was 94% of that of the bagasse filter mud compost with both Sargassum powder and compound microbial agent added. This indicates that adding only Sargassum powder has a certain promoting effect on compost humification. However, compared with the bagasse filter mud compost with both Sargassum powder and compound microbial agent added, adding only Sargassum powder has a relatively slow start-up of the compost fermentation process and a poor effect on prolonging the high-temperature period.

[0047] Example 3

[0048] MI group: The additives contain only 5% of the total wet weight of the mixture of compound microbial agents, and the ratio of Bacillus licheniformis to Phanerochaete chrysosporium is 1:1, without the addition of Sargassum fusiforme powder.

[0049] (1) Raw material pretreatment: Mix bagasse and filter mud at a ratio of 1.42:1, adjust the initial moisture content of the mixture to 60%, and the carbon-nitrogen ratio (C / N) to 28:1; (2) Selection of additives: 5% of the total wet weight of the bagasse and filter mud mixture is added to the mixture. The compound microbial agent is composed of live bacteria preparations of Bacillus licheniformis and Phanerochaete chrysosporium at a live bacteria ratio of 1:1, with a concentration of 1*10⁻⁶. 8 CFU / mL; (3) Composting fermentation: After the composting raw materials are mixed evenly, they are piled in a 60L composting bucket for aerobic fermentation. During the high-temperature fermentation stage of composting, the temperature of the pile is controlled at 55-65℃. The pile is turned regularly to promote ventilation and uniform fermentation. (4) Composting and aging: When the temperature of the pile naturally drops to the ambient temperature and the material has no odor and is dark brown and loose, age it for 10 days to obtain composted fertilizer. (5) Method for making compost: Dry the compost in a cool and ventilated place until the moisture content is reduced to 20% to make solid fertilizer.

[0050] The results showed that the compost with only the compound microbial agent added entered the high-temperature period about 48 hours after the pile was built, and the high-temperature period lasted for 10 days. After 45 days of fermentation, the humic content reached 128.88 mg / g (of which the humic acid content was 66.30%), which was 89% of that of the bagasse filter mud compost with both Sargassum powder and compound microbial agent added. This indicates that adding only the compound microbial agent has a certain promoting effect on compost humification. Although it effectively prolongs the high-temperature period of compost, compared with the bagasse filter mud compost with both Sargassum powder and compound microbial agent added, adding only Sargassum powder has a relatively slower start-up of the compost fermentation process and a less effective humification degree.

[0051] Example 4

[0052] SMI group: the experimental group, which received two functional additives simultaneously. (1) Raw material pretreatment: Mix bagasse and filter mud at a ratio of 1.42:1, adjust the initial moisture content of the mixture to 60%, and the carbon-nitrogen ratio (C / N) to 28:1; (2) Selection of additives: 5% of the total wet weight of Sargassum fusiforme powder and 5% of the total wet weight of the mixture were added to the bagasse and filter mud mixture. The compound microbial agent was prepared by mixing live bacteria of Bacillus licheniformis and Phanerochaete chrysosporium at a live bacteria ratio of 1:1, with a concentration of 1*10⁻⁶. 8 CFU / mL; (3) Composting fermentation: After the composting raw materials are mixed evenly, they are piled in a 60L composting bucket for aerobic fermentation. During the high-temperature fermentation stage of composting, the temperature of the pile is controlled at 55-65℃. The pile is turned regularly to promote ventilation and uniform fermentation. (4) Composting and aging: When the temperature of the pile naturally drops to the ambient temperature and the material has no odor and is dark brown and loose, age it for 10 days to obtain composted fertilizer. (5) Method for making compost: Dry the compost in a cool and ventilated place until the moisture content is reduced to 20% to make solid fertilizer.

[0053] The results showed that the compost with both functional additives added rapidly heated to over 55°C within 24 hours, reaching its highest temperature (64°C) on the 5th day, with the high-temperature period extending to 11 days (compared to 5 days for the CK group compost). This effectively killed pathogens in the compost, meeting the standards for safe application into the soil. The germination index of cabbage seeds reached 134.96%, an increase of 11.67% compared to the CK group, indicating that the compost product obtained by the filter mud composting method of this invention can effectively promote seed germination. After 45 days of fermentation, the humic content of the compost with both functional additives added reached 143.97 mg / g, an increase of 24.29% compared to the CK group (the humic content of the CK group was 115.83 mg / g); the humic acid content was 74.86 mg / g, an increase of 22.64% compared to the CK group. (The humic acid content in the CK group was 61.04 mg / g), indicating that the filter mud composting method of the present invention can effectively improve the humification degree of compost products.

[0054] Example 5

[0055] (1) Raw material pretreatment: Mix bagasse and filter mud at a ratio of 1.42:1, adjust the initial moisture content of the mixture to 60%, and the carbon-nitrogen ratio (C / N) to 28:1; (2) Selection of additives: 5% of the total wet weight of Sargassum fusiforme powder and 5% of the total wet weight of the mixture were added to the bagasse and filter mud mixture. The compound microbial agent was prepared by mixing live bacteria of Trichoderma longibrachiatum and Phanerochaete chrysosporium at a live bacteria ratio of 1:1, with a concentration of 1*10. 8 CFU / mL; (3) Composting fermentation: After the composting raw materials are mixed evenly, they are piled in a 60L composting bucket for aerobic fermentation. During the high-temperature fermentation stage of composting, the temperature of the pile is controlled at 55-65℃. The pile is turned regularly to promote ventilation and uniform fermentation. (4) Composting and aging: When the temperature of the pile naturally drops to the ambient temperature and the material has no odor and is dark brown and loose, age it for 10 days to obtain composted fertilizer. (5) Method for making compost: Dry the compost in a cool and ventilated place until the moisture content is reduced to 20% to make solid fertilizer.

[0056] The results showed that only the compost produced by this compound microbial agent entered the high-temperature period about 48 hours after the compost was built, and the high-temperature period lasted for 9 days. After 45 days of fermentation, the humic content reached 108.83 mg / g (of which the humic acid content was 62.46%), which was 75.59% of that of the bagasse filter mud compost with both Sargassum powder and compound microbial agent added. This indicates that the simultaneous addition of Trichoderma longifolia and Protozoa chrysophagus has a certain effect on the humification of compost, but the fermentation process starts relatively slowly and the effect on the degree of humification of compost is limited.

[0057] Example 6

[0058] (1) Raw material pretreatment: Mix bagasse and filter mud at a ratio of 1.42:1, adjust the initial moisture content of the mixture to 60%, and the carbon-nitrogen ratio (C / N) to 28:1; (2) Selection of additives: Add 5% of the total wet weight of rice husk biochar and 5% of the total wet weight of compound microbial agent to the mixture of bagasse and filter mud. The compound microbial agent is prepared by mixing live bacteria of Bacillus licheniformis and Phanerochaete chrysosporium at a live bacteria ratio of 1:1, with a concentration of 1*10. 8 CFU / mL; (3) Composting fermentation: After the composting raw materials are mixed evenly, they are piled in a 60L composting bucket for aerobic fermentation. During the high-temperature fermentation stage of composting, the temperature of the pile is controlled at 55-65℃. The pile is turned regularly to promote ventilation and uniform fermentation. (4) Composting and aging: When the temperature of the pile naturally drops to the ambient temperature and the material has no odor and is dark brown and loose, age it for 10 days to obtain composted fertilizer. (5) Method for making compost: Dry the compost in a cool and ventilated place until the moisture content is reduced to 20% to make solid fertilizer.

[0059] The results showed that the compost with rice husk biochar and compound microbial agent added simultaneously entered the high-temperature period about 24 hours after the compost was built, and the high-temperature period lasted for 9 days. After 45 days of fermentation, the humic content reached 124.09 mg / g (of which the humic acid content was 60.26%), which was 86.19% of that of bagasse filter mud compost with Sargassum powder and compound microbial agent added simultaneously. This indicates that the simultaneous addition of rice husk biochar and compound microbial agent can promote the rapid start of the compost humification fermentation process, but the effect of prolonging the high-temperature period and the humification effect on the compost are not good.

[0060] Example 7

[0061] (1) Raw material pretreatment: Mix bagasse and filter mud at a ratio of 1.42:1, divide into three groups, and adjust the initial mixture moisture content to 60% and carbon-nitrogen ratio (C / N) to 28:1; (2) Selection of additives: 2%, 5% and 8% of the total wet weight of the mixture were added to the three groups of bagasse and filter mud mixtures, respectively; (3) Composting fermentation: After mixing the three sets of composting raw materials evenly, they are piled in a 60L composting bucket for aerobic fermentation. During the high-temperature fermentation stage of composting, the temperature of the pile is controlled at 55-65℃. The pile is turned regularly to promote ventilation and uniform fermentation. (4) Composting and aging: When the temperature of the pile naturally drops to the ambient temperature and the material has no odor and is dark brown and loose, age it for 10 days to obtain composted fertilizer. (5) Method for making compost: Dry the compost in a cool and ventilated place until the moisture content is reduced to 20% to make solid fertilizer.

[0062] The results showed that compost with 2% Sargassum fusiforme powder entered the high-temperature period approximately 72 hours after composting, and this period lasted for 6 days. Compost with 5% and 8% Sargassum fusiforme powder entered the high-temperature period approximately 48 hours after composting, and this period lasted for 8 and 9 days, respectively. After 45 days of fermentation, the compost with 2% Sargassum fusiforme had a humic content of 119.28 mg / g (of which the humic acid content was 62.70 mg / g); the compost with 5% Sargassum fusiforme had a humic content of 135.95 mg / g (of which the humic acid content was 71.57 mg / g); and the compost with 8% Sargassum fusiforme had a humic content of 123.19 mg / g (of which the humic acid content was 52.79 mg / g).

[0063] In summary, adding too little Sargassum fusiforme (2%) is not conducive to rapid fermentation initiation and prolongs the high-temperature period of composting; adding too much (8%) can prolong the high-temperature period of composting to some extent, but fermentation is incomplete, and the stability of the generated humic matter is insufficient, specifically manifested in a low humic acid generation efficiency of 42.85% (calculation formula: humic acid generation efficiency = humic acid content / humic matter content); when the addition amount is 5%, the high-temperature period of composting can be prolonged, the stability of the generated humic matter is better, and the humic acid generation efficiency is 52.64%. Therefore, adding 5% Sargassum fusiforme is the optimal amount.

Claims

1. A method for composting filter mud based on the synergistic effect of Sargassum fusiforme and compound microbial agents, characterized in that, Includes the following steps: (1) Raw material pretreatment: Mix bagasse with filter mud and adjust the moisture and carbon-nitrogen ratio; (2) Selection of additives: Sargassum powder and compound microbial agent are added to the mixture of bagasse and filter mud at the same time. The amount of Sargassum powder added is 4% to 6% of the total wet weight of the compost material, and the amount of compound microbial agent added is 4% to 6% of the total wet weight of the compost material. The compound microbial agent is composed of Bacillus licheniformis and Protozoa chrysophagus. (3) Composting fermentation: After the composting raw materials are mixed evenly, the pile is built for aerobic fermentation. The pile is turned over regularly to promote aeration and uniform fermentation. (4) Composting and aging: When the temperature of the pile naturally drops to the ambient temperature and the material has no odor and is dark brown and loose, age it for 10 days to obtain composted fertilizer. (5) Method for making compost: Dry the compost in a cool and ventilated place until the moisture content is reduced to 20% to make solid fertilizer.

2. The method according to claim 1, characterized in that, The dry weight mixing ratio of bagasse and filter mud in the raw material pretreatment is (1:1) to (3:2).

3. The method according to claim 1, characterized in that, The carbon-to-nitrogen ratio (C / N) of the bagasse-filter mud mixture in the raw material pretreatment is 28:1, and the water content of the bagasse-filter mud mixture is 60%.

4. The filter mud composting method based on the synergistic effect of Sargassum fusiforme and compound microbial agents according to claim 1, characterized in that, In the selection of the additive, the ratio of viable bacteria of Bacillus licheniformis to Phanerochaete chrysosporium is (1:1) to (2:1), and the concentration is 1*10. 8 CFU / mL.

5. The filter mud composting method based on the synergistic effect of Sargassum fusiforme and compound microbial agents according to claim 1, characterized in that, The composting fermentation process is aerobic fermentation, and the temperature of the compost pile is controlled at 55-65℃ during the high-temperature fermentation stage.

6. The filter mud composting method based on the synergistic effect of Sargassum fusiforme and compound microbial agents according to claim 1, characterized in that, The preparation method of Sargassum powder is as follows: (1) Pretreatment: Rinse fresh, mold-free Sargassum seaweed 3-5 times with clean water to remove impurities such as mud and sand attached to the surface, and drain the surface water; (2) Desalination: (a) Cut the pretreated Sargassum fusiforme into 2-3 cm pieces and add deionized water at a solid-liquid ratio of 1:10; (b) Soak at room temperature (25°C) for 3 hours, stirring once every hour for about 1 minute each time; (c) After soaking for 3 hours, replace with deionized water and repeat the soaking process 2-3 times, for a total soaking time of 6-9 hours; (d) After soaking, rinse quickly 2-3 times with deionized water and drain. (e) Take the supernatant after the last soaking and measure the conductivity with a conductivity meter. When EC ≤ 500 μS / cm, it indicates that the desalination standard has been met. (3) Drying: Spread the desalted Sargassum evenly on a tray, with a thickness of 1-2 cm. Set the oven drying temperature to 55℃ and dry with forced air for 12-16 h until constant weight is achieved. After drying, remove the Sargassum and place it in a desiccator to cool to room temperature. (4) Crushing and sieving: The dried seaweed is put into a crusher for crushing. After crushing, it is passed through a 60-mesh sieve to obtain seaweed powder. It is then sealed and stored in a dry and cool place.

7. A decomposed compost product and its organic fertilizer prepared by the method according to any one of claims 1-6.

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