A method for rapidly fermenting domestic sludge and a fermentation additive
Patent Information
- Application Number
- CN202611140757.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-07-30
- Publication Date
- 2026-10-20
Smart Images
Figure FT_1 
Figure SMS_3
Abstract
Description
Technical Field
[0001] This invention relates to the field of sludge biological treatment technology, specifically to a method for rapid fermentation of domestic sewage sludge and a fermentation additive. Background Technology
[0002] Domestic sewage sludge is a major byproduct of wastewater treatment, containing large amounts of organic matter, pathogenic microorganisms, and malodorous substances. If not properly treated, it will cause serious environmental pollution. Aerobic fermentation (composting) is one of the important methods for treating domestic sewage sludge. Its principle is to use the metabolic activities of microorganisms to decompose and transform the organic matter in the sludge, thereby achieving volume reduction, stabilization, and harmlessness.
[0003] The existing aerobic fermentation technology for domestic sewage sludge has the following main shortcomings:
[0004] (i) Long fermentation cycle. Traditional methods use relatively simple fermentation agents with insufficient microbial activity, resulting in slow temperature rise during fermentation. The temperature of the pile is difficult to rise above 60°C, and it usually takes more than 20 days or even longer to basically complete the fermentation.
[0005] (II) Severe Odor Pollution. Sludge itself contains precursors of odorous substances such as ammonia, nitrogen, and sulfur, which release large amounts of odorous gases such as hydrogen sulfide, ammonia, and methanethiol during fermentation. The main odorous components released during aerobic fermentation of sludge are volatile substances such as ketones, aromatic hydrocarbons, alcohols, sulfides, and terpenes. Current technologies lack effective in-situ deodorization methods, making it difficult to meet environmental protection requirements and becoming a bottleneck restricting the widespread application of aerobic fermentation of sludge.
[0006] (iii) Incomplete harmlessness. Due to insufficient fermentation temperature or insufficient duration of high temperature, harmful microorganisms and roundworm eggs in the sludge are difficult to be completely killed, and the fermentation products pose health and safety hazards.
[0007] (iv) Odor removal relies on end-of-pipe treatment. Currently, the treatment of odor from sludge fermentation mainly adopts end-of-pipe treatment methods such as chemical absorption and activated carbon adsorption. These methods involve large equipment investment and high operating costs, and fail to solve the odor generation problem at its source. Summary of the Invention
[0008] The purpose of this invention is to address the above-mentioned shortcomings by providing a rapid fermentation method for domestic sewage sludge and a fermentation additive, which significantly shortens the fermentation cycle; achieves rapid temperature rise; inhibits the generation and release of malodorous gases from the source, significantly reducing the concentration of odorous substances; thoroughly kills harmful microorganisms and roundworm eggs, ensuring the hygiene and safety of fermentation products; and improves the degradation rate of organic matter.
[0009] To achieve the above objectives, the present invention adopts the following technical solution:
[0010] A method for rapid fermentation of domestic sewage sludge includes the following steps:
[0011] S1. Take domestic sewage sludge and prepare fermentation raw materials according to the following volume ratio: 14-16% bacterial residue, 9-11% straw, 8%-10% animal manure, add 2%-3% compound microbial agent and 4-6% fruit enzyme, mix evenly to obtain a mixture; the compound microbial agent has more than 10 billion live bacteria per milliliter;
[0012] S2, pile the mixture obtained in S1 into a rectangular stack, 1.2 to 1.5 meters high, and let it sit naturally without pressing it down. Then spray the plant-derived biological deodorizer to cover the surface of the stack. Make holes in the surface of the stack at 30 cm intervals, with a hole depth of 50 to 80 cm. Then cover it with plastic film and insert a thermometer to monitor the temperature.
[0013] S3, First Turning: When the pile temperature rises to 45℃, the pile is turned over for the first time. The pile is turned over evenly upside down and side to side, and then piled up again to maintain a height of 1.2 to 1.5 meters.
[0014] S4, Continuous turning: After the first turning, turn the pile once every 2 days, 3 days, and 3 days.
[0015] S5, Fermentation End: Fermentation ends when the temperature of the pile naturally drops to the ambient temperature.
[0016] Preferably, the compound microbial agent contains microbial strains of Bacillus subtilis, Bacillus licheniformis, Bacillus amyloliquefaciens, Bacillus megaterium, Bacillus proteus, Bacillus cereus, yeast, actinomycetes, and lactic acid bacteria.
[0017] Preferably, the compound microbial agent further includes 10% to 13% nitrifying bacteria and denitrifying bacteria.
[0018] Preferably, the fruit enzyme is made from pineapple and / or banana through anaerobic fermentation.
[0019] Preferably, the plant-derived bio-deodorant is made from hardwood through high-temperature carbonization.
[0020] Preferably, the mushroom residue is at least one of king oyster mushroom residue, oyster mushroom residue, or shiitake mushroom residue.
[0021] Preferably, the moisture content of the mixture in step S1 is controlled at 60% to 65%.
[0022] Preferably, the fermentation temperature is controlled below 75°C in the method, and the initial temperature of the mixture in step S1 is above 15°C.
[0023] A fermentation additive that can be used in any of the above-mentioned rapid fermentation methods for domestic sewage sludge includes compound microbial agents and fruit enzymes;
[0024] The compound microbial agent contains microbial strains of Bacillus subtilis, Bacillus licheniformis, Bacillus amyloliquefaciens, Bacillus megaterium, Bacillus proteus, Bacillus cereus, yeast, actinomycetes, and lactic acid bacteria, with a viable count of more than 10 billion per milliliter, and is added at 2% to 3% of the sludge material volume.
[0025] The fruit enzyme is made from pineapple and / or banana through anaerobic fermentation for more than 3 months, and the amount added is 4-6% of the volume of sludge material.
[0026] Preferably, the compound microbial agent also contains 10% to 13% nitrifying bacteria and denitrifying bacteria.
[0027] The beneficial effects of this invention are:
[0028] This invention significantly improves the metabolic activity of microorganisms through the synergistic effect of compound microbial agents and fruit enzymes, enabling the temperature of the fermentation pile to rise to above 60°C within 3 days, and reach 68-71°C on the 5th day and maintain it for about 5 days. The entire fermentation cycle only takes 10-15 days, which is more than 40% shorter than the traditional method of more than 20 days.
[0029] This invention utilizes the synergistic effect of plant-derived biological deodorizers and microbial fermentation to suppress the generation and release of malodorous gases at the source. During the fermentation process, the concentration of odorous substances (mainly hydrogen sulfide, ammonia, methanethiol, etc.) released from the pile to the outside environment can be reduced by 84.3% to 94%, and the entire fermentation process is basically odorless, eliminating the need for additional end-of-pipe deodorization equipment.
[0030] The compost temperature of this invention is maintained above 60°C for approximately 5 days, effectively killing most harmful microorganisms, E. coli, and ascarid eggs in the sludge. Testing showed that the mortality rate of E. coli and ascarid eggs in the fermentation products was zero, meeting hygiene and safety standards.
[0031] The compound microbial agent of this invention has the synergistic effect of multiple microorganisms, which can decompose various complex organic matter in sludge, achieve full degradation of organic matter, and make the fertilizer efficiency indicators of the fermentation products exceed the national organic fertilizer standards.
[0032] This invention does not add any chemical substances throughout the entire process, relying entirely on biological functions to treat sludge. The fermentation products can be used as organic fertilizer or soil conditioner, thus realizing resource utilization. Attached Figure Description
[0033] Figure 1 This is a process flow diagram of the rapid fermentation method for domestic sewage sludge according to the present invention. Detailed Implementation
[0034] Example 1
[0035] 1. Preparation of fermentation additives
[0036] Preparation of compound microbial inoculant: A mixture of microbial strains is prepared, primarily Bacillus subtilis, including Bacillus licheniformis, Bacillus amyloliquefaciens, Bacillus megaterium, Bacillus proteus, Bacillus cereus, yeasts (such as Candida albicans, baker's yeast, Rhodotorula rubra, and Candida utilis), actinomycetes (such as Streptomyces albopictus, Streptomyces griseus, and Streptomyces thermophilus), and lactic acid bacteria (such as Lactobacillus plantarum, Lactobacillus fermentum, Streptococcus lactis, Streptococcus acidophilus, and Streptococcus thermophilus). Simultaneously, 10%–13% nitrifying and denitrifying bacteria are added. After propagation and culture, the total viable count is ≥10 billion CFU / mL (i.e.,...). (Above). All the strains mentioned above were obtained from the Microbiology Laboratory of the College of Resources and Environment, Northwest A&F University (some strains currently in use have been sent to professional biological identification institutions for identification and related patent applications have been applied for). They were formulated through a large number of experiments. During the experiments, different sludge components were treated separately, and the composition of the residues after treatment was detected to obtain the optimal formulation ratio. The ratio of bacilli, lactic acid bacteria and actinomycetes was 7:2:1.
[0037] Preparation of fruit enzymes: Using pineapple and banana from the south as the main raw materials (mass ratio 1:1), fermentation is carried out according to conventional anaerobic fermentation process for enzymes. The fermentation cycle is 3 months. The resulting enzyme liquid contains a variety of organic acids, enzymes and active substances.
[0038] Preparation of plant-derived biological deodorizer: It is made from seven kinds of hardwood (jujube, apple, pear, poplar, winged locust, Chinese locust, and persimmon) through high-temperature carbonization treatment. When using, it can be diluted 30 times and sprayed.
[0039] 2. Fermentation methods for domestic sewage sludge
[0040] 10 m³ of domestic sewage sludge was taken from a wastewater treatment plant. 1.5 m³ (15%) of mushroom residue (king oyster mushroom residue), 1.0 m³ (10%) of crop straw, and 0.9 m³ (9%) of cow manure were added by volume. 0.25 m³ (2.5%) of the aforementioned compound microbial agent and 0.5 m³ (5%) of fruit enzyme were also added, and the mixture was thoroughly stirred. The moisture content of the mixture was found to be 63%. When the material was tightly grasped in the hand, water would seep between the fingers but not drip, and it would naturally disperse upon landing. The initial temperature was 18℃.
[0041] Stack the mixed materials into rectangular windrows, 1.3 meters high and 8 meters long, allowing them to lie naturally without compaction. Spray the plant-based bio-deodorizer onto the surface of the pile until it is completely covered. Use a 5 cm diameter wooden stick to drill holes at 30 cm intervals, 60 cm deep. Then cover with plastic film. Insert thermometers at different locations in the center and at both ends of the pile to monitor temperature changes continuously.
[0042] 3. Fermentation process monitoring and turning management
[0043] On the third day, the temperature of the reactor core rose to 62°C; on the fifth day, the temperature of the reactor core reached a maximum of 69°C and remained around this temperature for about 5 days.
[0044] When the temperature of the pile reaches 45℃ (on the second day), the pile is turned over for the first time. The pile is turned over evenly upside down and left and right, and then piled up again, keeping the pile height at 1.3 meters.
[0045] Two days after the first turning (i.e., the fourth day), the pile is turned a second time, turning it evenly from top to bottom and left to right, and then piled up again.
[0046] Three days after the second turning (i.e., the 7th day), the pile is turned a third time, turning it evenly from top to bottom and left to right, and then piled up again.
[0047] Three days after the third turning (i.e., the 10th day), the pile is turned a fourth time, turning it evenly from top to bottom and left to right, and then piled up again.
[0048] Add an appropriate amount of water each time you turn the pile to maintain a moisture content of 60% to 65%.
[0049] On the 13th day, the temperature of the pile naturally dropped to the ambient temperature (22℃), and fermentation ended.
[0050] 4. Detection of fermentation products
[0051] The fermentation product obtained in this embodiment was sent to a qualified testing institution for testing, and the test results are as follows:
[0052] Escherichia coli: Not detected (0 MPN / g);
[0053] Ascaris egg mortality rate: 100% (zero detected);
[0054] Odor detection: During the fermentation process, olfactory detection was conducted at a distance of 1 meter from the pile, and no obvious odor was found; instrumental testing showed that the concentration of odorous substances such as hydrogen sulfide, ammonia, and methanethiol released from the pile to the outside environment was reduced by 84.3% to 94% overall;
[0055] Fertilizer efficiency indicators: organic matter content, total nutrients The content, pH value and other indicators all exceed the national organic fertilizer standard (NY / T 525-2021).
[0056] Example 2
[0057] The difference between this embodiment and Embodiment 1 is that the raw material ratio and fermentation scale have been adjusted.
[0058] Take 20 m³ of domestic sewage sludge, and add 3.0 m³ (15%) of mushroom residue (a 1:1 mixture of oyster mushroom residue and shiitake mushroom residue), 2.0 m³ (10%) of crop straw, and 1.6 m³ (8%) of pig manure by volume. Also add 0.6 m³ (3%) of compound microbial agent, 1.0 m³ (5%) of fruit enzyme (based on pineapple), and 0.2 m³ (1%, half of the total amount) of biological deodorizer. Mix thoroughly. The moisture content of the mixture is 62%, and the initial temperature is 20℃.
[0059] Stack the mixture into rectangular windrows, 1.5 meters high and 12 meters long, and leave them to rest naturally without pressing. Spray the remaining 0.2 m³ (1%) of biological deodorizer onto the surface of the windrow. Use a 5 cm diameter wooden stick to drill holes at 30 cm intervals, 70 cm deep. Cover with plastic film and insert a thermometer to monitor the temperature.
[0060] Fermentation process: On day 3, the pile temperature rises to 63℃, and on day 5 it reaches 70℃, with the high temperature lasting for about 5 days. When the pile temperature rises to 45℃ (day 2), the pile is turned for the first time, and thereafter turned at intervals of 2 days, 3 days, and 3 days. On day 14, the pile temperature naturally drops to ambient temperature, and fermentation ends.
[0061] After fermentation, the fermentation products were tested. Escherichia coli was not detected, the mortality rate of Ascaris eggs was 100%, the concentration of odor-causing substances was reduced by 84.3% to 94%, and all fertilizer efficiency indicators exceeded the national organic fertilizer standards.
[0062] Example 3
[0063] The difference between this embodiment and Embodiment 1 is that the source of the substrate is shiitake mushroom substrate.
[0064] Take 5 m³ of domestic sewage sludge and add 0.75 m³ (15%) of shiitake mushroom residue, 0.5 m³ (10%) of crop straw, and 0.5 m³ (10%) of cow manure by volume. Also add 0.1 m³ (2%) of compound microbial agent, 0.25 m³ (5%) of fruit enzyme (based on bananas), and 0.05 m³ (1%, half of the total amount) of biological deodorizer. Mix thoroughly. The moisture content of the mixture is 65%, and the initial temperature is 16℃.
[0065] Stack the mixture into rectangular windrows, 1.2 meters high and 5 meters long, and leave them to rest naturally without pressing. Spray the remaining 0.05 m³ (1%) of biological deodorizer onto the surface of the windrow. Use a 5 cm diameter wooden stick to make holes at 30 cm intervals, 50 cm deep. Cover with plastic film and insert a thermometer to monitor the temperature.
[0066] Fermentation process: On day 3, the pile temperature rose to 60℃, and on day 5 it reached 68℃, with the high temperature lasting for about 5 days. Turning and turning management were the same as in Example 1. On day 12, the pile temperature naturally dropped to ambient temperature, and fermentation ended.
[0067] After fermentation, the test results showed that E. coli was not detected, the mortality rate of Ascaris eggs was 100%, the concentration of odor-causing substances was reduced by 84.3% to 94%, and all fertilizer efficiency indicators exceeded the national organic fertilizer standards.
[0068] Example 4
[0069] Fermentation Additive Formulation Verification Example
[0070] This embodiment is used to verify the synergistic effect of compound microbial agents and fruit enzymes in fermentation additives.
[0071] Using the same sewage sludge, mushroom residue, straw, animal manure, and operating methods as in Example 1, the following comparative group was set up:
[0072] Experimental group (this invention): 2.5% compound microbial agent, 5% fruit enzyme, and 2% biological deodorizer were added.
[0073] Control group 1: 2.5% compound microbial agent was added, but no fruit enzymes or biological deodorizers were added.
[0074] Control group 2: 5% fruit enzyme was added, but no compound bacterial agent or biological deodorizer was added.
[0075] Control group 3: 2.5% compound microbial agent and 5% fruit enzyme were added, but no biological deodorizer was added.
[0076] Control group 4: A commercially available single bacterial agent (Bacillus subtilis single agent) was added to replace the compound bacterial agent of the present invention, with an addition amount of 2.5%, along with 5% fruit enzyme and 2% biological deodorizer.
[0077] The fermentation results of each group are compared below.
[0078] Table 1 Comparison of fermentation results
[0079] The comparative experimental data above show that the compound microbial agent and fruit enzyme have a significant synergistic effect. When used alone, they have a slow heating rate and low degradation rate. Although the combination of the two (control group 3) also achieved good results, the odor control was still inferior to the present invention's solution with added biological deodorizer. Meanwhile, when commercially available single microbial agents (control group 4) were used to replace the multiple compound microbial agents of the present invention, all indicators were significantly inferior to the present invention, proving that the combination of multiple strains in the present invention and their synergistic effect with fruit enzyme and biological deodorizer are the key to achieving excellent technical results.
[0080] The specific embodiments described herein are merely illustrative examples of the invention. Those skilled in the art to which this invention pertains may make various modifications or additions to the described specific embodiments or use similar methods to substitute them, without departing from the scope defined by this invention.
Claims
1. A method for rapid fermentation of domestic sewage sludge, characterized in that: Includes the following steps: S1. Take domestic sewage sludge and prepare fermentation raw materials according to the following volume ratio: 14-16% bacterial residue, 9-11% straw, 8%-10% animal manure, add 2%-3% compound microbial agent and 4-6% fruit enzyme, mix evenly to obtain a mixture; the compound microbial agent has more than 10 billion live bacteria per milliliter; S2, pile the mixture obtained in S1 into a rectangular stack, 1.2 to 1.5 meters high, and let it sit naturally without pressing it down. Then spray the plant-derived biological deodorizer to cover the surface of the stack. Make holes in the surface of the stack at 30 cm intervals, with a hole depth of 50 to 80 cm. Then cover it with plastic film and insert a thermometer to monitor the temperature. S3, First Turning: When the pile temperature rises to 45℃, the pile is turned over for the first time. The pile is turned over evenly upside down and side to side, and then piled up again to maintain a height of 1.2 to 1.5 meters. S4, Continuous turning: After the first turning, turn the pile once every 2 days, 3 days, and 3 days. S5, Fermentation End: Fermentation ends when the temperature of the pile naturally drops to the ambient temperature.
2. The method for rapid fermentation of domestic sewage sludge according to claim 1, characterized in that, The compound microbial agent contains microbial strains of Bacillus subtilis, Bacillus licheniformis, Bacillus amyloliquefaciens, Bacillus megaterium, Bacillus proteus, Bacillus cereus, yeast, actinomycetes, and lactic acid bacteria.
3. The method for rapid fermentation of domestic sewage sludge according to claim 2, characterized in that, The compound microbial agent also includes 10% to 13% nitrifying bacteria and denitrifying bacteria.
4. The method for rapid fermentation of domestic sewage sludge according to claim 1, characterized in that, The fruit enzyme is made from pineapple and / or banana through anaerobic fermentation.
5. The method for rapid fermentation of domestic sewage sludge according to claim 1, characterized in that, The plant-derived bio-deodorant is made from hardwood through high-temperature carbonization.
6. The method for rapid fermentation of domestic sewage sludge according to claim 1, characterized in that, The mushroom residue is at least one of king oyster mushroom residue, oyster mushroom residue, or shiitake mushroom residue.
7. The method for rapid fermentation of domestic sewage sludge according to claim 1, characterized in that, In step S1, the moisture content of the mixture is controlled at 60% to 65%.
8. The method for rapid fermentation of domestic sewage sludge according to claim 1, characterized in that, The fermentation temperature is controlled below 75℃ in the method, and the initial temperature of the mixture in step S1 is above 15℃.
9. A fermentation additive that can be used in the rapid fermentation method of domestic sewage sludge according to any one of claims 1-8, characterized in that, Including compound microbial agents and fruit enzymes; The compound microbial agent contains microbial strains of Bacillus subtilis, Bacillus licheniformis, Bacillus amyloliquefaciens, Bacillus megaterium, Bacillus proteus, Bacillus cereus, yeast, actinomycetes, and lactic acid bacteria, with a viable count of more than 10 billion per milliliter, and is added at 2% to 3% of the sludge material volume. The fruit enzyme is made from pineapple and / or banana through anaerobic fermentation for more than 3 months, and the amount added is 4-6% of the volume of sludge material.
10. A fermentation additive for rapid fermentation of municipal sewage sludge according to claim 9, characterized in that, The compound microbial agent also contains 10% to 13% nitrifying bacteria and denitrifying bacteria.