A reusable sludge aerobic fermentation auxiliary material, preparation and application

Abstract

The application discloses a reusable sludge aerobic fermentation auxiliary material, and preparation and application thereof, belongs to the technical field of sludge aerobic fermentation, and overcomes the defects of high cost of adding auxiliary materials in the prior art.The application provides a reusable sludge aerobic fermentation auxiliary material, which is a wood piece with a diameter of 2-3 cm and a thickness of 0.5-1 cm; the wood piece is provided with holes, and the water content of the wood piece is less than 20 wt% 。 The wood piece can reduce the water content of sludge, improve porosity, thereby reducing the adding amount of other auxiliary materials, reducing the cost of the auxiliary materials, and the wood piece can be reused, and the cost can be further reduced.

Description

Technical Field

[0001] This invention belongs to the field of aerobic fermentation technology for sludge, specifically relating to a reusable aerobic fermentation auxiliary material for sludge, its preparation and application. Background Technology

[0002] Aerobic fermentation is one of the mainstream treatment technologies for sludge. Sludge has a high water content (generally 80 wt%), is viscous, and has extremely low porosity. Under natural conditions, its interior is an anaerobic environment, making it extremely difficult to supply oxygen and maintain an aerobic state. The high water content and low content of easily decomposable organic matter in sludge also make it difficult to quickly initiate aerobic fermentation. These are the main bottlenecks in aerobic fermentation of sludge.

[0003] Adding auxiliary materials is a core element of the aerobic fermentation process for sludge. Commonly used auxiliary materials include mushroom residue, straw, corn cobs, peanut shells, and cottonseed hulls. The main purpose of adding auxiliary materials is to create three necessary conditions for the aerobic fermentation of the sludge mixture: reducing the sludge moisture content to around 60 wt%, achieving a suitable level for aerobic microbial activity; increasing the porosity of the sludge mixture, as the sludge particle structure is adjusted, allowing externally supplied oxygen to reach the interior of the mixture, creating an aerobic environment that promotes the aerobic reaction process and ensures the aerobic fermentation of the sludge; and providing easily decomposable organic components, providing reaction substrates for the initial activity of aerobic microorganisms, enabling rapid initiation of aerobic fermentation and maintaining temperature rise. Generally, the auxiliary materials begin aerobic fermentation before the sludge. The energy and environment generated by the fermentation of the auxiliary materials can drive the fermentation of organic matter in the sludge, thus achieving overall temperature rise of the mixture and ultimately achieving the maturation of the mixture. Adding auxiliary materials is key to the rapid initiation of aerobic fermentation of sludge.

[0004] Aerobic fermentation of sludge requires a certain proportion of auxiliary materials. Currently, many sludge treatment projects use a sludge-to-auxiliary material volume ratio of approximately 1:1. With the increasing demand for organic waste materials from industries such as organic fertilizer, biomass incineration, and livestock farming, the prices of auxiliary materials such as mushroom residue, straw, corn cobs, peanut shells, and cottonseed hulls have gradually risen in recent years. Adding auxiliary materials has become a major source of cost for aerobic fermentation projects, and an unstable or unsustainable supply of these materials will severely impact the stable operation of such projects, potentially leading to reduced or halted production.

[0005] Chinese invention patent (ZL 200810137214.8) utilizes pumice with a particle size of 0.2-10 cm as a conditioner. The pumice conditioner is mixed with sludge and then subjected to aerobic fermentation without the use of other auxiliary materials or well-rotted return mix. The pumice conditioner increases the porosity of the sludge and improves aeration efficiency. However, pumice cannot reduce the moisture content of the sludge, and its soft texture, low mechanical strength, and poor toughness make it prone to breakage during mixing and turning in aerobic fermentation.

[0006] Chinese utility model patent (ZL 201721876823.6) utilizes artificially produced hollow cylindrical material as an auxiliary material to reduce the need for other auxiliary materials. This material is made of polypropylene, which cannot reduce the moisture content of sludge; it requires mold production, resulting in high costs; and polypropylene ages and breaks down during mechanical turning, mixing, and other processes.

[0007] Chinese invention patent (ZL 201310158220.2) proposes a method for composting sludge without additives. This method involves extracting indigenous microorganisms from sludge composted at different temperatures to obtain fermentation inoculants, which are then inoculated into the sludge at the corresponding temperature range for fermentation. However, inoculating with inoculants without adding additives fails to address the bottleneck problems of high water content, viscosity, and difficulty in maintaining an aerobic state within the sludge. Furthermore, the multi-stage inoculation method presents certain engineering challenges. Summary of the Invention

[0008] Therefore, the technical problem to be solved by the present invention is to overcome the defect of high cost of adding auxiliary materials in the prior art, thereby providing a reusable aerobic fermentation auxiliary material for sludge, its preparation and application.

[0009] To this end, the present invention provides the following technical solution.

[0010] In a first aspect, the present invention provides a reusable aerobic fermentation feedstock for sludge, comprising wood chips with a diameter of 2-3 cm and a thickness of 0.5-1 cm; the wood chips have pores and a moisture content of <20 wt%. 。

[0011] Furthermore, the aperture of the hole is 2–4 mm;

[0012] Furthermore, each piece of wood has 3 to 7 holes;

[0013] Preferably, when the diameter of the wood chip is less than 2.5 cm, the wood chip has no more than 4 holes;

[0014] Preferably, when the diameter of the wood chip is greater than 2.5 cm, the number of holes on the wood chip is greater than 4;

[0015] Furthermore, the arrangement of multiple holes on the wooden chip is as follows: equilateral triangle, square, square and center point, regular pentagon, regular pentagon and center point, regular hexagon or regular hexagon and center point;

[0016] Furthermore, the center-to-center distance between adjacent holes is 0.9 to 1.8 cm; preferably, the center-to-center distance between any two adjacent holes is equal.

[0017] Optionally, the hole can be a round hole or a square hole.

[0018] Furthermore, the wood chips are wood chips that have undergone hydrothermal treatment;

[0019] Preferably, the hydrothermal treatment conditions are immersion in water at 50–90°C for 12–15 hours.

[0020] Secondly, the present invention provides a method for preparing a reusable aerobic fermentation adjuvant for sludge, comprising the following steps:

[0021] Step 1: Obtain wood chips with a diameter of 2-3 cm and a thickness of 0.5-1 cm;

[0022] Step 2: Drill holes in the wood slab;

[0023] Step 3: Dry the wood chips to a moisture content of <20wt% to obtain wood chips.

[0024] Furthermore, step 1 includes slicing raw materials with a diameter > 3cm into powder and then sieving them;

[0025] Preferably, the raw materials are tree branches and / or trunks with a diameter >3cm after pruning for urban landscaping;

[0026] It is best to use trees that are not easily rotten, such as branches and / or trunks of trees like sycamore, camphor, Chinese scholar tree, or poplar.

[0027] Preferably, a two-stage drum screen is used for screening.

[0028] Furthermore, step 2 satisfies at least one of the following conditions:

[0029] (1) Drill holes when the moisture content of the wood chips is ≥30wt%;

[0030] (2) The diameter of the hole is 2-4 mm;

[0031] (3) Drill 3 to 7 holes in each wooden slab;

[0032] Preferably, when the diameter of the wood chip is less than 2.5 cm, the wood chip has no more than 4 holes;

[0033] (4) The arrangement of multiple holes on the wood chip is an equilateral triangle, a square, a square and its center point, a regular pentagon, a regular pentagon and its center point, a regular hexagon or a regular hexagon and its center point;

[0034] (5) The center-to-center distance between adjacent holes is 0.9 to 1.8 cm; preferably, the center-to-center distance between any two adjacent holes is equal.

[0035] Furthermore, between steps 2 and 3, hydrothermal treatment is performed on the perforated wood chips.

[0036] Preferably, the hydrothermal treatment conditions are immersion in water at 50–90°C for 12–15 hours.

[0037] Thirdly, the present invention also provides a reusable aerobic fermentation adjuvant for sludge, or the application of a reusable aerobic fermentation adjuvant for sludge prepared according to the preparation method described above, in aerobic fermentation of sludge.

[0038] Furthermore, the volume ratio of the reusable sludge aerobic fermentation auxiliary material is less than 70% of the total auxiliary material volume, where the total auxiliary material volume refers to the total volume of all types of auxiliary materials added during the sludge aerobic fermentation process.

[0039] Furthermore, after completing one aerobic fermentation of sludge, the wood chips are screened out using a vibrating screen, dried to a moisture content of <20wt%, and then put into the next aerobic fermentation of sludge.

[0040] Preferably, when the blockage rate of the holes on the wood chip is ≥30%, a vibrating screen is used to shake out the blockage material in the holes until the blockage rate of the holes on the wood chip is ≤10%; the blockage rate of the holes refers to the proportion of the number of blocked holes on the wood chip to the total number of holes on the wood chip.

[0041] Preferably, wood chips that have been reused more than 10 times are subjected to hydrothermal treatment again and dried to a moisture content of <20wt%.

[0042] Preferably, when the moisture content of the wood chips is <30wt%, they should be soaked in water for 12-24 hours, drained, and then the holes should be drilled.

[0043] Optionally, drying can be done by natural air drying.

[0044] Specifically, the aerobic fermentation temperature for ordinary sludge is 50-65℃, while the aerobic fermentation temperature for ultra-high temperature sludge is 70-90℃.

[0045] Furthermore, the application method of wood chips is as follows: the obtained wood chips replace part of other auxiliary materials, are mixed with sludge according to the conventional material mixing ratio, and then subjected to aerobic fermentation. Other auxiliary materials can be at least one of mushroom residue, straw, corn cobs, peanut shells, etc.

[0046] Furthermore, after the sludge mixture has fermented and decomposed, the wood chips are screened out using a vibrating screen with a aperture of 1 to 1.6 cm. During the screening process, some of the decomposed sludge mixture that was blocked in the small holes of the wood chips can be discharged.

[0047] The technical solution of this invention has the following advantages:

[0048] 1. The reusable aerobic fermentation aid for sludge in this invention is wood chips with a diameter of 2-3 cm and a thickness of 0.5-1 cm; the wood chips have holes and a moisture content of <20 wt%. 。

[0049] Due to the unique properties of sludge, aerobic fermentation requires certain conditions, such as reducing the sludge's moisture content to provide a suitable moisture environment and increasing the porosity of the sludge mixture to provide oxygen supply. The auxiliary material of this invention is wood, which has a high lignin content, is difficult to decompose, and is suitable for the aerobic fermentation environment of sludge. The wood chips have a diameter of 2-3 cm and a thickness of 0.5-1 cm, making them easy to perforate and preventing breakage during use, allowing for reuse. The perforations in the wood chips increase the porosity and permeability of the sludge mixture, resulting in more thorough aeration and oxygen supply. They also enhance the adhesion of the auxiliary material to microorganisms, creating a breeding ground for microorganisms in the sludge mixture. The wood chips have a moisture content of <20 wt%, and the dry wood chips can quickly absorb moisture from the sludge, rapidly reducing the moisture content of the sludge mixture.

[0050] The wood chips of this invention can reduce the moisture content of sludge and increase its porosity, thereby reducing the amount of other auxiliary materials to be added and lowering the cost of auxiliary materials. Furthermore, the wood chips can be reused, which can further reduce costs.

[0051] 2. The diameter of the holes in the wood chips of this invention is 2-4 mm, and the center-to-center distance between adjacent holes is 0.9-1.8 cm. Within this range, the strength of the wood chips can be guaranteed, preventing breakage; at the same time, it ensures that the wood chips can function properly for air permeability and microbial adhesion.

[0052] 3. The wood chips of this invention are wood chips that have undergone hydrothermal treatment. Hydrothermal treatment can remove some resin and other substances, improve the toughness of the wood chips, making them less prone to breakage, thereby increasing their service life and the number of times they can be reused.

[0053] 4. The hydrothermal treatment conditions of this invention are soaking in water at 50-90℃ for 12-15 hours. Hydrothermal treatment is performed by maintaining a high-temperature and humidity environment during the aerobic fermentation period of sludge, utilizing the memory function of wood materials to better adapt them to the aerobic fermentation environment.

[0054] 5. In the preparation method of reusable aerobic fermentation auxiliary material for sludge, drilling holes when the moisture content of the wood chips is ≥30wt% can avoid the wood chips cracking due to drilling holes in the dried wood chips.

[0055] 6. The raw material of this invention is fresh tree branches and trunks with a diameter >3cm after pruning in urban landscaping. It uses waste tree branches and trunks generated from landscaping pruning as raw materials to process sludge aerobic fermentation auxiliary material. The material selection is green and environmentally friendly, the cost is low, the processing is convenient, and it also promotes the recycling of landscaping waste.

[0056] 7. When reusable sludge aerobic fermentation auxiliary materials are used in sludge aerobic fermentation, the volume ratio of the reusable sludge aerobic fermentation auxiliary materials shall be less than 70% of the total volume of the auxiliary materials, so as to avoid affecting the normal start-up, heating and other processes of aerobic fermentation.

[0057] This invention provides a reusable aerobic fermentation additive for sludge that can reduce the moisture content of sludge and effectively increase the porosity of the sludge mixture. It can replace a certain amount of other additives such as mushroom residue, straw, corn cobs, peanut shells, and cottonseed hulls, while not completely replacing other easily perishable organic additives. It does not affect the normal start-up and heating processes of aerobic fermentation, and enables the repeated use of the additive, which is of great significance for reducing the cost of aerobic fermentation. Attached Figure Description

[0058] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0059] Figure 1 This is a process flow diagram for the preparation and application of the reusable aerobic fermentation auxiliary material for sludge according to the present invention.

[0060] Figure 2 This is a schematic diagram showing the arrangement of holes punched on the wooden sheet in Example 1;

[0061] Figure 3 This is a schematic diagram of the arrangement of holes punched on the wooden sheet in Example 2. Detailed Implementation

[0062] The following embodiments are provided to better understand the present invention and are not limited to the preferred embodiments described. They do not constitute a limitation on the content and scope of protection of the present invention. Any product that is the same as or similar to the present invention, derived by any person under the guidance of the present invention or by combining the features of the present invention with other prior art, falls within the protection scope of the present invention.

[0063] For experiments not specifically described in the examples, the procedures or conditions should be followed according to the conventional experimental procedures described in the literature in this field. Reagents or instruments whose manufacturers are not specified are all commercially available conventional reagent products.

[0064] Example 1

[0065] This embodiment provides a reusable aerobic fermentation additive for sludge, as well as its processing and application methods, such as... Figure 1 As shown, it includes the following steps:

[0066] 1. Select fresh sycamore tree branches and trunks with a diameter of 5-10cm after pruning for urban landscaping. Remove leaves and thin branches and leaves with a diameter <2cm, then shred them using a shredder. Sift the shredded branches and leaves using a two-stage drum sieve to obtain wood chips that are approximately 2.2cm in diameter and 0.5cm thick. The moisture content of the wood chips is 35wt%.

[0067] 2. Lay the selected wood chips evenly and use a wood drilling machine to drill circular holes in the wood chips. Set the center-to-center distance between holes to 1cm, and the diameter of each hole to 3mm. Drill 3 holes arranged in an equilateral triangle on each wood chip, as shown below. Figure 2 As shown.

[0068] 3. Soak the drilled wood chips in water at 55℃ for 15 hours.

[0069] 4. After hydrothermal treatment, the wood chips are naturally air-dried to a moisture content of 18 wt%. The resulting wood chips are the target auxiliary material of Example 1.

[0070] 5. Mix the wood chips, mushroom residue, and sludge (sludge moisture content 80wt%) obtained in step 4 at a volume ratio of 0.5:0.5:1 to obtain a sludge mixture (i.e., wood chips replace 50% of the mushroom residue). Carry out aerobic fermentation at a temperature of 50-60℃ during the high-temperature fermentation period. The amount of mushroom residue used is reduced by half compared to conventional fermentation.

[0071] 6. After the sludge mixture has fermented and decomposed, the wood chips are screened out using a vibrating screen with a 1.5cm aperture. During the screening process, some of the decomposed sludge mixture that was blocked in the small holes of the wood chips can be discharged.

[0072] 7. When the screened wood chips are naturally air-dried to a moisture content of 19wt%, samples are taken at 30 points to observe the degree of blockage of the small holes on the wood chips. The blockage rate is 7%. The wood chips are then used to replace the mushroom residue and mix with the sludge for aerobic fermentation.

[0073] After the wood chips have been reused for the 11th time, they are processed in steps 3 and 4 before being reused.

[0074] In step 5, wood chips, mushroom residue, and sludge are mixed evenly at a volume ratio of 0.5:0.5:1 and allowed to stabilize for 3 days. A sample of the mixture is then taken, and the wood chips are removed to determine the moisture content, which is between 60 and 64 wt%. This demonstrates that wood chips can absorb water, reducing the moisture content of the sludge to a suitable level.

[0075] By the fifth aerobic fermentation using wood chips, 94% of the total volume remained, with each aerobic fermentation cycle resulting in a loss of approximately 1-2%.

[0076] Example 2

[0077] This embodiment provides a reusable aerobic fermentation additive for sludge, as well as its processing and application methods, such as... Figure 1 As shown, it includes the following steps:

[0078] 1. Select fresh sycamore tree branches and trunks with a diameter of about 10cm after pruning for urban landscaping. Remove the leaves and thin branches and leaves with a diameter of <2cm, then crush them with a chipper and shredder. Use a two-stage drum sieve to screen out wood chips that are in the form of flakes with a diameter of about 2.9cm and a thickness of about 0.5cm.

[0079] 2. Due to the lack of timely follow-up treatment, the wood chips were air-dried for a period of time, and the moisture content decreased to 20 wt%. The wood chips were soaked in water for 24 hours and then drained.

[0080] 3. Lay the drained wood chips evenly and use a wood punch to make small circular holes in each chip. Make five holes on each chip, four of which are arranged in a square, with the center-to-center distance between adjacent holes at the vertices of the square set at 1.5cm; the fifth hole is located in the exact center of the square; each hole has a diameter of 3mm. Figure 3 As shown.

[0081] 4. Immerse the drilled wood chips in water at 80℃ for hydrothermal treatment for 12 hours.

[0082] 5. After hydrothermal treatment, the wood chips are naturally air-dried to a moisture content of 19 wt%. The resulting wood chips are the target auxiliary material of Example 2.

[0083] 6. Mix the wood chips, straw, and sludge (sludge moisture content 78wt%) obtained in step 5 at a volume ratio of 0.6:0.4:1 to obtain a sludge mixture (i.e., wood chips replace 60% of the straw), and add ultra-high temperature aerobic fermentation inoculant for aerobic fermentation. The temperature during the high-temperature fermentation period can reach 80-90℃.

[0084] 7. After 20 days of fermentation, the sludge mixture is fully fermented and decomposed. Use a vibrating screen with a 1cm aperture to separate the wood chips. During the screening process, some of the decomposed sludge mixture that was blocking the small holes in the wood chips can be discharged.

[0085] 8. Allow the screened wood chips to air dry naturally until the moisture content reaches 18 wt%. Sampling is performed to observe the degree of blockage in the wood chip holes. The proportion of blocked holes is 38%. The wood chips are then screened twice with a vibrating screen to remove the sludge mixture that is blocking the wood chip holes, reducing the proportion of blocked holes to 10%.

[0086] 9. After the above treatment, the wood chips are mixed with the sludge again to replace other auxiliary materials and then carried out aerobic fermentation.

[0087] 10. After the wood chips have been reused for the 11th time, process them in steps 4 and 5 before using them again.

[0088] In step 6, the wood chips, mushroom residue, and sludge are mixed evenly at a volume ratio of 0.6:0.4:1 and stabilized for 3 days. Then, a sample of the mixture is taken, the wood chips are removed, and the moisture content is measured. The moisture content value is between 58 and 62 wt%.

[0089] By the fifth aerobic fermentation using wood chips, 93% of the total volume remained, with each aerobic fermentation cycle resulting in a loss of approximately 1-2%.

[0090] Comparative Example 1

[0091] This comparative example provides an aerobic fermentation process for sludge, including the following steps: In this comparative example, pumice, mushroom residue, and sludge (sludge moisture content of 80wt%) are mixed evenly at a volume mixing ratio of 0.5:0.5:1 to obtain a sludge mixture (i.e., pumice replaces 50% of mushroom residue), and aerobic fermentation is carried out. The temperature during the high-temperature fermentation period is 50-60℃.

[0092] After the sludge mixture has fermented and decomposed, pumice is sieved out using a vibrating screen with a 1cm aperture. The sieved pumice is then dried for 3-5 days and used to replace the mushroom residue in the sludge mixture for aerobic fermentation.

[0093] Pumice is fragile and has low mechanical strength, making it prone to breakage during the aerobic composting process. Actual measurements show that after the fifth aerobic fermentation using pumice, only 58% of the total amount remains, with each aerobic fermentation cycle resulting in a loss of approximately 8-10%.

[0094] In this comparative example, pumice, mushroom residue, and sludge were mixed uniformly at a volume ratio of 0.5:0.5:1 and stabilized for 3 days. A sample of the mixture was then taken, and the pumice was removed to determine its moisture content. The moisture content ranged from 74 to 77 wt%. Pumice does not absorb water; even after replacing part of the auxiliary materials with pumice, the moisture content of the sludge remained relatively high.

[0095] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A reusable aerobic fermentation additive for sludge, characterized in that, The wood chips are 2-3 cm in diameter and 0.5-1 cm thick; the wood chips have holes and the moisture content is <20 wt%. Each piece of wood has 3 to 7 holes; The aperture of the hole is 2~4mm; The center-to-center distance between adjacent holes is 0.9~1.8cm; The wood chips are hydrothermally treated wood chips; the hydrothermal treatment involves soaking in water at 50~90℃ for 12~15 hours; the hydrothermal treatment simulates the aerobic fermentation of sludge, maintaining a high-temperature and humidity environment, and utilizing the memory function of the wood chips to adapt them to the aerobic fermentation environment; the hydrothermal treatment removes some resin, improves the toughness of the wood chips, makes them less prone to breakage, and increases their service life and number of reuses.

2. The reusable aerobic fermentation additive for sludge according to claim 1, characterized in that, The arrangement of multiple holes on the wooden chip can be an equilateral triangle, a square, a square with its center point, a regular pentagon, a regular pentagon with its center point, or a regular hexagon or a regular hexagon with its center point.

3. The reusable aerobic fermentation additive for sludge according to claim 2, characterized in that, When the diameter of the wood chip is 2~2.5cm, there are 3~4 holes on the wood chip; And / or, the center-to-center distance between any two adjacent holes is equal.

4. A method for preparing a reusable aerobic fermentation additive for sludge, characterized in that, Includes the following steps: Step 1: Obtain wood chips with a diameter of 2-3cm and a thickness of 0.5-1cm; Step 2: Drill holes in the wood slab; Drill 3 to 7 holes in each wooden slab; The aperture of the hole is 2~4mm; The center-to-center distance between adjacent holes is 0.9~1.8cm; the wood slabs after drilling are also subjected to hydrothermal treatment; The hydrothermal treatment involves soaking the wood chips in water at 50-90°C for 12-15 hours. The hydrothermal treatment simulates the aerobic fermentation of sludge, maintaining a high-temperature and humidity environment. It utilizes the memory function of the wood chips to adapt them to the aerobic fermentation environment. The hydrothermal treatment removes some resin, improves the toughness of the wood chips, makes them less prone to breakage, and increases their service life and number of reuses. Step 3: Dry the wood chips until the moisture content is <20wt% to obtain wood chips.

5. The preparation method according to claim 4, characterized in that, Step 1 includes slicing, crushing and sieving raw materials with a diameter > 3cm.

6. The preparation method according to claim 5, characterized in that, The raw materials are tree branches and / or trunks with a diameter >3cm after pruning in urban landscaping. And / or, use a two-stage drum screen for screening.

7. The preparation method according to claim 4, characterized in that, Step 2 satisfies at least one of the following conditions: (1) Drill holes when the moisture content of the wood chips is ≥30wt%; (2) The arrangement of multiple holes on the wooden chip is an equilateral triangle, a square, a square and its center point, a regular pentagon, a regular pentagon and its center point, a regular hexagon or a regular hexagon and its center point; (3) The center distance between any two adjacent holes is equal.

8. The preparation method according to claim 7, characterized in that, When the diameter of the wood chip is 2 to 2.5 cm, there are 3 to 4 holes on the wood chip.

9. The application of a reusable sludge aerobic fermentation adjuvant according to any one of claims 1-3 or a reusable sludge aerobic fermentation adjuvant prepared by the preparation method according to any one of claims 4-8 in aerobic sludge fermentation.

10. The application according to claim 9, characterized in that, The volume ratio of the reusable sludge aerobic fermentation auxiliary material is less than 70% of the total auxiliary material volume, where the total auxiliary material volume refers to the total volume of all types of auxiliary materials added during the sludge aerobic fermentation process.

11. The application according to claim 9 or 10, characterized in that, After completing one round of aerobic fermentation of sludge, the wood chips are screened out using a vibrating screen and dried to a moisture content of <20wt% before entering the next round of aerobic fermentation of sludge.

12. The application according to claim 11, characterized in that, When the blockage rate of the holes in the wood chips is ≥30%, a vibrating screen is used to shake out the blockage material in the holes until the blockage rate of the holes in the wood chips is ≤10%. And / or, re-hydrothermally treat wood chips that have been reused more than 10 times and dry them to a moisture content of <20wt%.

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