A method for biological drying of municipal sewage sludge

Abstract

The invention relates to the field of sludge treatment and disposal, and provides a method for biological drying of municipal sludge, comprising: screening bacterial strains, taking core sludge in a high-temperature period of aerobic composting of municipal sludge, and selecting thermophilic bacterial strains; compounding bacterial agents, mixing thermophilic bacteria and autotrophic bacteria in a certain proportion, including thermophilic bacteria and autotrophic bacteria, and thermophilic bacteria and autotrophic bacteria are compounded in proportion; generating heat and heating, mixing the bacterial agent with a municipal sludge raw material and a conditioning agent and then fermenting; thermophilic autotrophy; air drying; turning the pile; mechanical filtration for 5-7 days to produce biomass fuel; repeating the above process n times per month; the invention adjusts the proportion of conditioning agents and the water content to meet the incineration requirements of thermal power plants, turns waste into treasure, and finally produces municipal sludge into biomass fuel rods, thereby realizing the resource utilization and reduction of municipal sludge.

Description

Technical Field

[0001] The invention relates to the field of sludge treatment and disposal, in particular to a method for biological drying of municipal sludge. Background Art

[0002] Municipal sludge is a misplaced resource. It contains rich organic matter and nutrients such as nitrogen, phosphorus, and potassium. If it is not properly disposed, it will cause air, water, and soil environmental pollution. According to the disposal goals of "reduction, stabilization, harmlessness, and resource utilization", common disposal methods include landfill, incineration, agricultural use, construction and engineering products, etc.

[0003] In the process of municipal sludge treatment, dehydration is the limiting relief of sludge disposal at the current stage. The water content of municipal sludge is generally greater than 90%. Before the sludge is harmlessly treated and recycled, the water content of the sludge must be reduced to less than 60%. When the sludge is used to make bricks or other construction and engineering materials, the water content needs to be reduced to less than 40%. When the sludge is used to make fertilizers or incinerate for power generation, the water content needs to be reduced to less than 30%. At present, the dehydrated sludge produced by urban sewage treatment plants usually has a relatively high water content. Even after concentration and dehydration treatment in the sewage treatment plant, its water content will still be as high as about 80%. At this time, the sludge has the disadvantages of large volume, unstable biochemical properties, and inconvenient transportation. Therefore, the sludge needs to be dried to reduce the water content of the sludge and reduce the volume of the sludge. This is the key to solving the current sludge disposal problem.

[0004] The current method for removing a large amount of water from sludge is to dry the sludge with a moisture content of about 80%; currently, the main sludge drying technologies include thermal drying and dehydration technology, hydrothermal dehydration technology, deep dehydration technology, biological drying technology, etc.; thermal drying technology mainly includes electric energy drying method, steam drying method, solar energy drying method, etc.; the electric energy drying method has the disadvantages of high energy consumption and low efficiency, and is not suitable for sewage treatment plants with tight electricity supply and large amount of sludge. At the same time, it requires high temperature and high pressure dehydration equipment, which also limits its industrial scale; the steam drying method uses steam thermal energy to exchange heat through the shell of the heat exchanger. It has the disadvantages of high energy consumption and high investment, which is not in line with the concept of sustainable development; the solar energy drying method based on solar energy uses the traditional greenhouse drying process for drying, which is affected by the instability of solar radiation. Certain restrictions, large floor space and the volatilization of harmful ammonia gases produced can easily cause air pollution; hydrothermal dehydration technology is a technology for thermal dehydration of sludge at a temperature of 120-240°C in a closed pressure vessel. During the hydrothermal treatment, EPS dissolves or decomposes to release its bound water, cell walls are destroyed to overflow intracellular water, and difficult-to-degrade organic matter is converted into easily degradable substances to improve its biodegradability. Studies have shown that hydrothermal treatment at 180°C for 30 minutes can improve the dehydration of sludge, and the water content after filter pressing is reduced from 85% to 33%. However, the side reaction of forming coke and tar limits the practical application of this technology, and the energy consumption is high. It is limited by the surrounding environment according to local conditions. Therefore, the existing thermal drying method of dehydration technology has certain limitations in terms of energy consumption, ecology and environmental protection;

[0005] The biological drying technology of sludge was first proposed by Jewell et al. of Cornell University in the United States in 1984 when they studied the operating parameters of biological drying of cow dung. In the biological drying process, microorganisms degrade organic matter aerobically and generate heat, and a large amount of ventilation is used to remove moisture. The principle of biological drying is that microorganisms use the easily degradable organic matter in the sludge for aerobic respiration under ventilation and oxygen supply conditions, and release a large amount of bioenergy while meeting their own reproduction and growth needs. This part of bioenergy can significantly increase the temperature of the material, generally up to 55°C, and up to 70°C and above. At the same time, the activity of microorganisms can also activate the bound water in the sludge, making it easier to evaporate due to the increase in temperature. The water in the sludge is converted into water vapor through bioenergy heating, and enters the gap between the materials through forced convection and free diffusion, and is then taken out of the system by the dry air blown in by the fan, thereby achieving continuous dehydration and drying. The biological drying technology has the advantages of low energy consumption, low investment, short cycle, and small occupied area, and has a better development prospect in sludge treatment.

[0006] However, the existing biological drying technology still has problems such as slow heat generation, consumption of organic matter in sludge, reduction of sludge biomass properties, and difficulty in disposing of the dried sludge. Traditional sludge dewatering measures such as high energy consumption and easy pollution are gradually restricted. We should find new biological drying technologies that consume less organic matter, have low costs, energy conservation and environmental protection, and meet the requirements of my country's resource recycling and sustainable development. Summary of the invention

[0007] The present invention proposes a method for biological drying of municipal sludge. In order to utilize the minimum heat generation by degradation of organic matter and utilize inorganic matter as much as possible (retaining organic matter in sludge as energy material), sludge in the high temperature period of composting is utilized, thermophilic drying bacteria and autotrophic carbon capture bacteria are screened, including Bacillus subtilis, Bacillus licheniformis, etc., and a self-made compound bacterial agent is prepared. On the one hand, aerobic thermophilic bacteria provide heat for the pile body, so that water is converted into water vapor and discharged from the pile body; on the other hand, autotrophic bacteria do not need to consume ready-made organic matter, and utilize carbon dioxide to synthesize organic matter, thereby increasing the organic matter content in the sludge. Finally, the sludge can be dried to a water content (mass ratio) of 30-40% in 5-7 days. After that, a mechanical filter press is used to adjust the proportion of the conditioning agent and the water content to meet the incineration requirements of the thermal power plant, turning waste into treasure, and finally making the municipal sludge into biomass fuel rods, thereby realizing the resource utilization and reduction of the municipal sludge.

[0008] The technical solution of the present invention is achieved in this way:

[0009] A method for biological drying of municipal sewage sludge, comprising:

[0010] Screening bacteria: Take the core sludge of municipal sludge aerobic composting at high temperature and select thermophilic bacteria;

[0011] Compound bacterial agent, thermophilic bacteria and autotrophic bacteria are mixed in a certain proportion, including thermophilic bacteria and autotrophic bacteria, thermophilic bacteria and autotrophic bacteria are compounded in proportion, and can provide substrates for each other to reproduce and grow together;

[0012] Heat generation and temperature rise: the bacterial agent is mixed with municipal sludge raw materials and conditioners for fermentation. The pile has strong self-heating capacity, which can make the maximum temperature of the material above 75℃;

[0013] Thermophilic autotrophic, using inorganic matter for growth and reproduction, and producing organic matter;

[0014] Blast drying, in a high temperature environment, generates a large amount of water vapor, uses air convection to expel moisture, and performs rapid drying;

[0015] Turn the pile;

[0016] Mechanical filtration takes 5-7 days to produce biomass fuel;

[0017] Repeat the above process n times every month, and carry out sludge treatment in batches multiple times every month according to the amount of sludge produced and the speed of sludge treatment;

[0018] Wherein, heat generation and temperature rise, thermophilic autotrophy, air drying and compost turning are carried out simultaneously, or the air drying or compost turning is carried out regularly during the process of heat generation and temperature rise and thermophilic autotrophy.

[0019] Furthermore, when screening bacterial strains, the plate streak method is used to perform multiple enrichment and screening to screen the bacterial strains.

[0020] Furthermore, when screening bacterial strains, the thermophilic bacterial strains selected include but are not limited to Bacillus, Geobacillus, Ureibacillus or Firmicutes, and one or more of them are used. Usually, multiple bacterial strains are used at the same time to work together.

[0021] Furthermore, in the compound bacterial agent, the autotrophic bacteria used include but are not limited to Rhodococcus, desulfurization bacteria, and Alicyclobacillus, and one or more of them are used. Usually, multiple species are used at the same time to work together.

[0022] Furthermore, in the compound bacterial agent, the compound ratio of the thermophilic bacteria and the autotrophic bacteria is 100:1-1:100, such as 90:1, 80:1, 70:1, 75:1, 60:1, 55,1, 50:1, 40:1, 30:1, 1:1, 1:30, 1:50, 1:60, 1:70, 1:75, 1:80, etc., and adaptive adjustment is made within this range according to the composition of the sludge and the expected drying effect.

[0023] Furthermore, in the heat generation and temperature rise, the temperature rise time is 2-3 days, and the fermentation time is continued for another 2-4 days after the temperature rise, that is, the total time is 5-7 days.

[0024] Further, in the process of heat generation and temperature rise, the conditioning agent includes but is not limited to peanut shells, wheat straw or bark, and one or more of them are used, for example, peanut shells, wheat straw or bark can be used alone, a mixture of peanut shells and wheat straw, a mixture of peanut shells and bark, a mixture of wheat straw and bark, etc. can be used;

[0025] The mass ratio of the conditioning agent to the sludge is: 1:3-1:5, for example, 1:3.5, 1:3.7, 1:3.8, 1:3.9, 1:4, 1:4.5, 1:5, etc.

[0026] Furthermore, during heat generation and temperature rise, the ratio of the bacterial agent to the municipal sludge and the conditioning agent is 10L:10T:1T-10L:10T:3T, for example, 10L:10T:1.5T, 10L:10T:1.75T, 10L:10T:2T, 10L:10T:2.25T, 10L:10T:2.5T.

[0027] Furthermore, the heat production and thermoautotrophic process are carried out synchronously with the heat production and the duration is 5-7 days.

[0028] Furthermore, in mechanical filtration, the moisture content of the sludge is reduced to 30-40% after mechanical filtration. The sludge with a moisture content of about 30-40% is squeezed and molded with a conditioning agent through mechanical filtration to produce biomass fuel with a calorific value of 2000-3500 kcal / kg. -1 Around 2000 tons are used for incineration to generate electricity;

[0029] The water content of the biomass fuel is lower than 20%, and the water content can be reduced to 18%, 15%, and 12%.

[0030] The present invention aims to utilize the minimum heat generation by degradation of organic matter and utilize inorganic matter as much as possible (retaining organic matter in sludge as energy material). The present invention utilizes sludge in the high temperature period of composting, screens thermophilic drying bacteria and autotrophic carbon capture bacteria, including Bacillus subtilis, Bacillus licheniformis, etc., and prepares a self-made compound bacterial agent. On the one hand, aerobic thermophilic bacteria provide heat for the pile body, convert water into water vapor, and discharge it from the pile body; on the other hand, autotrophic bacteria do not need to consume ready-made organic matter, utilize carbon dioxide to synthesize organic matter, and increase the organic matter content in the sludge. Finally, the sludge can be dried to a moisture content (mass ratio) of 30-40% in 5-7 days. After that, a mechanical filter press is used to adjust the proportion of the conditioning agent and the moisture content to meet the incineration requirements of the thermal power plant, turning waste into treasure, and finally making the municipal sludge into biomass fuel rods, thereby realizing the resource utilization and reduction of municipal sludge. DETAILED DESCRIPTION

[0031] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0032] In a specific embodiment 1 of the present invention, a method for biological drying of municipal sludge includes: screening bacterial strains, taking the core sludge of the municipal sludge aerobic composting high temperature period, and selecting thermophilic bacterial strains;

[0033] Compound bacterial agent, thermophilic bacteria and autotrophic bacteria are mixed in a certain proportion, including thermophilic bacteria and autotrophic bacteria. Thermophilic bacteria can grow in medium and high temperature environments. Thermophilic bacteria and autotrophic bacteria are compounded in proportion, and can provide substrates to each other and reproduce and grow together;

[0034] Heat generation and temperature rise: the bacterial agent is mixed with municipal sludge raw materials and conditioners for fermentation. The pile has strong self-heating capacity, which can make the maximum temperature of the material above 75℃;

[0035] Thermophilic autotrophic, using inorganic matter for growth and reproduction, and producing organic matter;

[0036] Blast drying, in a high temperature environment, generates a large amount of water vapor, uses air convection to expel moisture, and performs rapid drying;

[0037] Turn the pile;

[0038] Mechanical filtration takes 5-7 days to produce biomass fuel;

[0039] Repeat the above process n times every month, and carry out sludge treatment in batches multiple times every month according to the amount of sludge produced and the speed of sludge treatment;

[0040] Wherein, heat generation and temperature rise, thermophilic autotrophy, air drying and compost turning are carried out simultaneously, or the air drying or compost turning is carried out regularly during the process of heat generation and temperature rise and thermophilic autotrophy.

[0041] Furthermore, when screening bacterial strains, the plate streak method is used to perform multiple enrichment and screening to screen the bacterial strains.

[0042] Furthermore, when screening bacterial strains, the selected thermophilic bacterial strains include but are not limited to Bacillus, Geobacillus, Ureibacillus, and Firmicutes. The genus Thermophilic bacteria includes more than a dozen species, and multiple thermophilic bacterial genera are mixed and used together.

[0043] Furthermore, in the compound bacterial agent, the autotrophic bacteria used include but are not limited to Rhodococcus, desulfurization bacteria, Alicyclobacillus, and the autotrophic bacteria include more than a dozen species, and multiple thermophilic bacteria are mixed and used together.

[0044] Furthermore, in the compound bacterial agent, the compounding ratio of the thermophilic bacteria genus to the autotrophic bacteria genus is 1:1.

[0045] Furthermore, in the heat generation temperature rise, the temperature rise time is 2 days, and the fermentation time is until 2 days after the temperature rise.

[0046] Furthermore, in the process of generating heat and raising temperature, the conditioning agent is peanut shell.

[0047] Furthermore, during the heat generation and temperature rise, the ratio of the bacterial agent to the municipal sludge and the conditioning agent is 10L:10T:1T.

[0048] Furthermore, the heat production and thermoautotrophic process are carried out synchronously with the heat production and the duration is 5.5 days.

[0049] Furthermore, in the mechanical filtration, after heat generation, thermophilic autotrophy and compost turning, the moisture content is reduced to about 50%. The sludge with a moisture content of about 40% is squeezed and molded with a conditioner through mechanical filtration to produce biomass fuel. The moisture content of the biomass fuel is about 20%.

[0050] In a second specific embodiment of the present invention, a method for biological drying of municipal sludge includes: screening bacterial strains, taking the core sludge of the municipal sludge aerobic composting high temperature period, and selecting thermophilic bacterial strains;

[0051] Compound bacterial agent, thermophilic bacteria and autotrophic bacteria are mixed in a certain proportion, including thermophilic bacteria and autotrophic bacteria, thermophilic bacteria and autotrophic bacteria are compounded in proportion, and can provide substrates for each other to reproduce and grow together;

[0052] Heat generation and temperature rise: the bacterial agent is mixed with municipal sludge raw materials and conditioners for fermentation. The pile has strong self-heating capacity, which can make the maximum temperature of the material above 75℃;

[0053] Thermophilic autotrophic, using inorganic matter for growth and reproduction, and producing organic matter;

[0054] Blast drying, in a high temperature environment, generates a large amount of water vapor, uses air convection to expel moisture, and performs rapid drying;

[0055] Turn the pile;

[0056] Mechanical filtration takes 5-7 days to produce biomass fuel;

[0057] Repeat the above process n times every month, and carry out sludge treatment in batches multiple times every month according to the amount of sludge produced and the speed of sludge treatment;

[0058] Wherein, heat generation and temperature rise, thermophilic autotrophy, air drying and compost turning are carried out simultaneously, or the air drying or compost turning is carried out regularly during the process of heat generation and temperature rise and thermophilic autotrophy.

[0059] Furthermore, when screening bacterial strains, the plate streak method is used to perform multiple enrichment and screening to screen the bacterial strains.

[0060] Furthermore, when screening bacterial strains, the selected thermophilic bacterial strains include but are not limited to Bacillus, Geobacillus, Ureibacillus, Firmicutes, and the thermophilic bacteria genus includes more than a dozen species, and multiple thermophilic bacteria genera are mixed and used together.

[0061] Furthermore, in the compound bacterial agent, the autotrophic bacteria used include but are not limited to Rhodococcus, desulfurization bacteria, Alicyclobacillus, and the autotrophic bacteria include more than a dozen species, and multiple thermophilic bacteria are mixed and used together.

[0062] Furthermore, in the compound bacterial agent, the compounding ratio of the thermophilic bacteria to the autotrophic bacteria is 1:50.

[0063] Furthermore, in the heat generation temperature rise, the temperature rise time is 2.5 days, and the fermentation time is 3 days after the temperature rise.

[0064] Furthermore, in the process of heat generation and temperature rise, the conditioning agent is wheat straw.

[0065] Furthermore, during the heat generation and temperature rise, the ratio of the bacterial agent to the municipal sludge and the conditioning agent is 10L:10T:2T.

[0066] Furthermore, the heat production and thermoautotrophic process are carried out synchronously with the heat production and the duration is 6 days.

[0067] Furthermore, in the mechanical filtration, after heat generation, thermophilic autotrophy, and compost turning, the moisture content drops to about 30%. The sludge with a moisture content of about 30% is squeezed and molded with a conditioner through mechanical filtration to produce biomass fuel. The moisture content of the biomass fuel is about 16%.

[0068] In a third specific embodiment of the present invention, a method for biological drying of municipal sludge includes: screening bacterial strains, taking the core sludge of the municipal sludge aerobic composting high temperature period, and selecting thermophilic bacterial strains;

[0069] Compound bacterial agent, thermophilic bacteria and autotrophic bacteria are mixed in a certain proportion, including thermophilic bacteria and autotrophic bacteria, thermophilic bacteria and autotrophic bacteria are compounded in proportion, and can provide substrates for each other to reproduce and grow together;

[0070] Heat generation and temperature rise: the bacterial agent is mixed with municipal sludge raw materials and conditioners for fermentation. The pile has strong self-heating capacity, which can make the maximum temperature of the material above 75℃;

[0071] Thermophilic autotrophic, using inorganic matter for growth and reproduction, and producing organic matter;

[0072] Blast drying, in a high temperature environment, generates a large amount of water vapor, uses air convection to expel moisture, and performs rapid drying;

[0073] Turn the pile;

[0074] Mechanical filtration for 5 days to produce biomass fuel;

[0075] Repeat the above process n times every month, and carry out sludge treatment in batches multiple times every month according to the amount of sludge produced and the speed of sludge treatment;

[0076] Wherein, heat generation and temperature rise, thermophilic autotrophy, air drying and compost turning are carried out simultaneously, or the air drying or compost turning is carried out regularly during the process of heat generation and temperature rise and thermophilic autotrophy.

[0077] Furthermore, when screening bacterial strains, the plate streak method is used to perform multiple enrichment and screening to screen the bacterial strains.

[0078] Furthermore, when screening bacterial strains, the selected thermophilic bacterial strains include but are not limited to Bacillus, Geobacillus, Ureibacillus, Firmicutes, and the thermophilic bacteria genus includes more than a dozen species, and multiple thermophilic bacteria genera are mixed and used together.

[0079] Furthermore, in the compound bacterial agent, the autotrophic bacteria used include but are not limited to Rhodococcus, desulfurization bacteria, Alicyclobacillus, and the autotrophic bacteria include more than a dozen species, and multiple thermophilic bacteria are mixed and used together.

[0080] Furthermore, in the compound bacterial agent, the compounding ratio of the thermophilic bacteria to the autotrophic bacteria is 1:100.

[0081] Furthermore, in the heat generation temperature rise, the temperature rise time is 3 days, and the fermentation time is 4 days after the temperature rise.

[0082] Further, in the case of heat generation and temperature rise, the conditioning agent is bark.

[0083] Furthermore, during the heat generation and temperature rise, the ratio of the bacterial agent to the municipal sludge and the conditioning agent is 10L:10T:3T.

[0084] Furthermore, the heat production and thermoautotrophic process are carried out synchronously with the heat production and the duration is 7 days.

[0085] Furthermore, in the mechanical filtration, after heat generation, thermophilic autotrophy, and compost turning, the moisture content drops to about 40%. The sludge with a moisture content of about 40% is squeezed and molded with a conditioner through mechanical filtration to produce biomass fuel. The moisture content of the produced biomass fuel is about 18%.

[0086] Furthermore, when screening bacterial strains, the selected thermophilic bacterial strains include but are not limited to Bacillus, Geobacillus, Ureibacillus, Firmicutes, and the thermophilic bacteria genus includes more than a dozen species, and multiple thermophilic bacteria genera are mixed and used together.

[0087] Furthermore, in the compound bacterial agent, the autotrophic bacteria used include but are not limited to Rhodococcus, desulfurization bacteria, Alicyclobacillus, and the autotrophic bacteria include more than a dozen species, and multiple thermophilic bacteria are mixed and used together.

[0088] Compared with the prior art, the advantages of the present invention are:

[0089] Compared with the traditional microbial drying treatment technology, the present invention uses a combination of autotrophic bacteria to capture carbon dioxide as organic matter, thereby reducing the energy loss in the sludge and retaining more heat energy for the later production of fuel rods; the high-temperature period is advanced, and the temperature will generally rise rapidly to above 55°C 12 to 24 hours after mixing, and remain for 3 to 5 days, which can achieve the purpose of rapid drying; since the entire drying cycle is short, less organic matter is used, and the microorganisms have a strong oxidizing effect, the ammonia and other odorous gases generated during the entire drying period are less than 1 / 2 of those generated by aerobic composting and other technologies, and have a very good deodorizing effect. If used in conjunction with technologies such as spraying EM bacteria, a basically complete deodorizing effect can be achieved.

[0090] Experimental process:

[0091] This process was used to treat 100 tons of sludge (80% moisture content) per day at the Xiaojianxi landfill in Qingdao. The project operation period was from April 20 to July 20, 2020.

[0092] The project needs to process 100 tons of sludge every day, and the input compound bacterial agent is 100L. The thermophilic bacteria and the autotrophic compound bacterial agent are put into the sludge, and then peanut shells are added (according to the mass ratio of sludge: peanut shells = 4:1) for stirring. The addition of peanut shells can increase the gaps in the sludge, facilitate air circulation, so that there is enough oxygen inside the sludge and the water vapor in the sludge is taken away. At the same time, large machinery such as forklifts are used to turn the pile to accelerate the circulation of water vapor;

[0093] After deep dehydration by biological drying, the moisture content of the sludge drops to below 35%. Subsequently, the sludge is filtered using a filter press and prepared into fuel rods with a moisture content below 20%. The sludge is then used for incineration to generate electricity. Part of the ash produced by the incineration is made into struvite for the recovery of nitrogen and phosphorus, and the remaining part is used to make radiation-proof building materials.

[0094] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for biological drying of municipal sludge, characterized in that include: Screening bacteria: Take the core sludge of municipal sludge aerobic composting at high temperature and select thermophilic bacteria; When screening bacterial strains, the thermophilic bacterial strains selected include one or more of Bacillus, Geobacillus, Ureibacillus or Firmicutes; A compound bacterial agent, which is composed of thermophilic bacteria and autotrophic bacteria, and the thermophilic bacteria and the autotrophic bacteria are mixed and compounded in a certain proportion; in the compound bacterial agent, the autotrophic bacteria used include one or more of Rhodococcus, desulfurization bacteria or Alicyclobacillus; Heat generation and temperature rise, the compound bacterial agent is mixed with the municipal sludge raw material and the conditioning agent and then fermented; during the heat generation and temperature rise, the temperature rise time is 2-3 days, and the fermentation time is continued for another 2-4 days after the temperature rise; Thermophilic autotrophic; Air drying; Turn the pile; Mechanical filtration takes 5-7 days to produce biomass fuel; Repeat the above process n times per month; Wherein, heat generation and temperature rise, thermophilic autotrophy, air drying and compost turning are performed simultaneously, or the air drying or compost turning is performed regularly during the heat generation and temperature rise and thermophilic autotrophy process; In the compound bacterial agent, the compounding ratio of the thermophilic bacteria to the autotrophic bacteria is 100:1-1:

100.

2. A method for biological drying of municipal sludge according to claim 1, characterized in that: When screening bacterial strains, the plate streak method is used to perform multiple enrichment and screening to screen the bacterial strains.

3. A method for biological drying of municipal sludge according to claim 1, characterized in that: In the heat generation and temperature rise, the conditioning agent includes one or more of peanut shells, wheat straw or bark, and the mass ratio of the conditioning agent to the sludge is 1:3-1:

5.

4. A method for biological drying of municipal sludge according to claim 1, characterized in that: During the heat generation and temperature rise, the ratio of the compound bacterial agent to the municipal sludge and the conditioning agent is 10L:10T:1T-10L:10T:3T.

5. A method for biological drying of municipal sludge according to claim 1, characterized in that: The heat production and thermoautotrophic process are carried out synchronously with the heat production and the duration is 5-7 days.

6. A method for biological drying of municipal sludge according to claim 1, characterized in that: In the mechanical filtration, sludge with a moisture content of about 30-40% and a conditioning agent are squeezed and formed by mechanical filtration to produce biomass fuel, wherein the moisture content of the biomass fuel is less than 20%.