A method for sludge purification conditioning using a composite carbon source

Abstract

The present application relates to the field of sludge conditioning, and particularly relates to a method for sludge purification conditioning using composite carbon source, which comprises the following steps: mixing sludge and alkaline solution, and then performing heating treatment to obtain pretreated sludge; then mixing the pretreated sludge with composite carbon source, and performing anaerobic fermentation to obtain treated sludge; adding dehydrating agent to the treated sludge, and then performing filtration to obtain dewatered sludge; performing drying treatment on the dewatered sludge, and then completing sludge purification conditioning; wherein the preparation method of the composite carbon source comprises the following steps: mixing calcium hydroxide suspension and aluminum chloride suspension, and then performing reaction to obtain hydrotalcite; mixing the hydrotalcite, chitosan and solvent, and then performing heating drying to obtain composite scaffold material; mixing the composite scaffold material, sodium alginate, peanut cake powder and wood-rotting fungi, and then performing dispersion to obtain composite solution; mixing the composite solution and calcium chloride solution to obtain composite carbon source. The method has the advantages of high treatment efficiency, low operation cost, less secondary pollution and the like.

Description

Technical Field

[0001] This invention relates to the field of sludge purification, and more specifically, to a method for sludge purification and conditioning using a composite carbon source. Background Technology

[0002] With the acceleration of industrialization and the continuous advancement of urbanization, the production of sewage sludge is increasing daily, and the purification and conditioning of sewage sludge has become an important problem that urgently needs to be solved in the field of environmental engineering. Sludge contains a large amount of pollutants such as organic matter, pathogens, and heavy metals, which will pose a serious threat to the environment and human health if not effectively treated.

[0003] Currently, sludge treatment methods mainly include physical dewatering, chemical conditioning, and biological treatment. Physical dewatering methods, such as mechanical filtration and centrifugal dewatering, can quickly reduce the water content of sludge, but their effect on the degradation of organic matter in the sludge is limited, and the dewatered sludge still has high viscosity and low stability. Chemical conditioning methods, by adding chemical agents such as flocculants and oxidants, can improve the dewatering performance and reduce the volume of sludge; however, the use of chemical agents may alter the properties of organic matter in the sludge and even cause secondary pollution. Biological treatment methods utilize the metabolic activity of microorganisms to decompose organic matter in sludge, offering advantages such as good treatment efficiency and environmental friendliness. However, traditional biological treatment methods often suffer from long treatment cycles, low efficiency, and high requirements for sludge pretreatment.

[0004] Furthermore, existing sludge treatment technologies face challenges in practical applications, including high costs, complex operations, and poor adaptability to sludge of different properties. Therefore, developing an efficient, environmentally friendly, and economical sludge purification and conditioning technology has become a research hotspot and urgent need in the field of environmental engineering. Summary of the Invention

[0005] In view of this, the present invention aims to provide a method for sludge purification and conditioning using composite carbon sources, in order to solve the problems of high cost, complex operation, and poor adaptability to different properties of sludge treatment technology in practical applications.

[0006] To solve the above-mentioned technical problems, this application is implemented as follows:

[0007] This invention provides a method for sludge purification and conditioning using a composite carbon source, comprising the following steps:

[0008] (1) After mixing the sludge and alkaline solution, a mixture is obtained and then heated to obtain pretreated sludge;

[0009] (2) The pretreated sludge and composite carbon source are mixed and anaerobic fermentation is carried out to obtain the treated sludge;

[0010] (3) Add a dewatering agent to the treated sludge and filter it to obtain dewatered sludge;

[0011] (4) Dry the dewatered sludge to complete the sludge purification and conditioning process;

[0012] The method for preparing the composite carbon source includes the following steps:

[0013] S1. Mix calcium hydroxide suspension and aluminum chloride suspension and react to obtain hydrotalcite; mix hydrotalcite, chitosan and solvent, and heat and dry to obtain composite scaffold material;

[0014] S2. Mix the composite scaffold material, sodium alginate, peanut cake powder, wood-decaying fungi, and water, and disperse them to obtain a composite solution;

[0015] S3. Mix the composite solution and the calcium chloride solution to obtain a composite carbon source.

[0016] Preferably, in the above-mentioned method for sludge purification and conditioning using a composite carbon source, in step (1), the alkaline solution includes at least one of potassium hydroxide solution, sodium hydroxide solution and calcium hydroxide solution;

[0017] In step (1), the pH of the mixture is 9 to 13;

[0018] In step (1), the temperature of the heat treatment is 100-150°C and the time of the heat treatment is 0.5-2h.

[0019] Preferably, in the above-mentioned method for sludge purification and conditioning using a composite carbon source, in step (2), the mass ratio of the pretreated sludge to the composite carbon source is 10-20:5-10.

[0020] In step (2), the temperature of the anaerobic fermentation is 35-40℃, and the time of the anaerobic fermentation is 15-20 days.

[0021] Preferably, in the above-mentioned method for sludge purification and conditioning using a composite carbon source, in step (3), the dehydrating agent includes polydimethylsiloxane;

[0022] In step (3), the amount of the dewatering agent used is 5 to 10% of the sludge mass.

[0023] Preferably, in the above-mentioned method for sludge purification and conditioning using a composite carbon source, in step (4), the drying temperature is 100-120°C and the drying time is 3-4 hours.

[0024] Preferably, in the above-mentioned method for sludge purification and conditioning using a composite carbon source, in step S1, the molar ratio of Ca in the calcium hydroxide suspension to Al in the aluminum chloride suspension is 3:1.

[0025] In step S1, the reaction temperature is 20–30°C, and the reaction time is 40–60 min.

[0026] Preferably, in the above-mentioned method for sludge purification and conditioning using a composite carbon source, in step S1, the mass ratio of the hydrotalcite to the chitosan is 5-10:5-10.

[0027] In step S1, the solvent includes water or an aqueous solution of ethanol with a volume fraction of 50-70%.

[0028] Preferably, in the above-mentioned method for sludge purification and conditioning using a composite carbon source, in step S1, the heating and drying temperature is 100-120°C, and the heating and drying time is 2-3 hours.

[0029] Preferably, in the above-mentioned method for sludge purification and conditioning using a composite carbon source, in step S2, the mass ratio of the composite support material, sodium alginate, peanut cake powder and wood-decaying fungi is 10-30:15-20:5-10:5-8.

[0030] In step S2, the wood-rotting fungi include white-rot fungi and / or brown-rot fungi.

[0031] Preferably, in the above-mentioned method for sludge purification and conditioning using a composite carbon source, in step S3, the volume ratio of the composite solution to the calcium chloride solution is 1-3:0.5-1.5;

[0032] In step S3, the concentration of the calcium chloride solution is 10–30 wt%.

[0033] The beneficial technical effects of the present invention through the above technical solution are as follows:

[0034] (1) The method for sludge purification and conditioning using a composite carbon source provided by this invention achieves synergistic effects among various substances through carefully designed composite carbon source preparation and sludge purification and conditioning steps, effectively improving the efficiency and quality of sludge treatment. In the preparation of the composite carbon source, the rational combination and compounding of hydrotalcite, chitosan, sodium alginate, peanut cake powder, and wood-rotting fungus white rot fungus forms a composite material with a porous structure, abundant carbon source, and microbial degradation ability, providing a good carbon source supplement and microbial growth environment for sludge treatment. In the sludge purification and conditioning process, the pretreatment with sodium hydroxide solution destroys the cell structure of the sludge and improves the biodegradability of the sludge; the addition of the composite carbon source provides microorganisms with abundant carbon source and nutrients, promoting the degradation of organic matter in the sludge; the wood-rotting fungus white rot fungus further decomposes the complex organic matter in the sludge, accelerating the decomposition and transformation of the sludge; finally, the dehydration effect of polydimethylsiloxane effectively removes the water in the sludge, achieving efficient dehydration and drying treatment of the sludge. The entire process is interconnected and mutually reinforcing, fully leveraging the roles of each substance to achieve excellent sludge purification and conditioning effects, demonstrating high application value and environmental benefits. Specifically, this system achieves multi-pathway removal of pollutants and resource recycling through a cascade of physical adsorption, chemical cross-linking, and biodegradation, exhibiting significant advantages such as high treatment efficiency, low operating costs, and minimal secondary pollution. It is particularly suitable for treating industrial sludge containing recalcitrant organic matter and heavy metal contamination.

[0035] (2) The method for preparing the composite carbon source provided by this invention involves a layered hydrotalcite formed by the reaction of calcium hydroxide and aluminum chloride. This hydrotalcite has a high specific surface area and interlayer ion exchange capacity, and can adsorb heavy metal ions and organic pollutants. Chitosan forms hydrogen bonds with the hydrotalcite through hydroxyl and amino groups to construct a three-dimensional porous network structure, providing an ideal carrier for subsequent microbial loading. Sodium alginate cross-links with calcium chloride to form Ca... 2+ A chelated gel is constructed to create a slow-release framework, controlling the carbon source release rate (the slow-release period can reach 15-20 days). Peanut cake powder provides an organic carbon source, promoting the proliferation of denitrifying bacteria. White-rot bacteria secrete lignin peroxidase and manganese peroxidase, effectively degrading refractory organic compounds such as phenols and polycyclic aromatic hydrocarbons. This composite carbon source, through a carefully designed preparation method, combines multiple substances with different functions to form a composite material with a porous structure, abundant carbon source, and microbial degradation capabilities. During sludge purification and conditioning, the various substances synergistically exert their multiple functions, including carbon source replenishment, microbial growth promotion, and sludge conditioning, effectively improving the efficiency and quality of sludge treatment. It has significant environmental benefits and economic value and can be widely applied in wastewater treatment and sludge disposal. Detailed Implementation

[0036] This invention discloses a method for sludge purification and conditioning using a composite carbon source. Those skilled in the art can refer to this document and appropriately modify the process parameters to achieve the desired result. It is particularly important to note that all similar substitutions and modifications are obvious to those skilled in the art and are considered to be included in this invention. The method and application of this invention have been described through preferred embodiments. Those skilled in the art can clearly modify or appropriately change and combine the methods and applications described herein without departing from the content, spirit, and scope of this invention to realize and apply the technology of this invention.

[0037] Unless otherwise specified, all embodiments and optional embodiments of this application can be combined to form new technical solutions.

[0038] Unless otherwise specified, all technical features and optional technical features of this application may be combined to form new technical solutions.

[0039] Unless otherwise specified, the terms "comprising" and "including" as used in this application can be open-ended or closed-ended. For example, "comprising" and "including" can mean that other components not listed may also be included, or that only the listed components may be included.

[0040] This invention provides a method for sludge purification and conditioning using a composite carbon source, comprising the following steps:

[0041] (1) After mixing the sludge and alkaline solution, a mixture is obtained and then heated to obtain pretreated sludge;

[0042] (2) The pretreated sludge and composite carbon source are mixed and anaerobic fermentation is carried out to obtain the treated sludge;

[0043] (3) Add a dewatering agent to the treated sludge and filter it to obtain dewatered sludge;

[0044] (4) Dry the dewatered sludge to complete the sludge purification and conditioning process;

[0045] The method for preparing the composite carbon source includes the following steps:

[0046] S1. Mix calcium hydroxide suspension and aluminum chloride suspension and react to obtain hydrotalcite; mix hydrotalcite, chitosan and solvent, and heat and dry to obtain composite scaffold material;

[0047] S2. Mix the composite scaffold material, sodium alginate, peanut cake powder, wood-decaying fungi, and water, and disperse them to obtain a composite solution;

[0048] S3. Mix the composite solution and the calcium chloride solution to obtain a composite carbon source.

[0049] In this invention, in step (1), the alkaline solution includes at least one of potassium hydroxide solution, sodium hydroxide solution and calcium hydroxide solution.

[0050] In this invention, in step (1), the pH of the mixture is preferably 9 to 13, more preferably 10 to 13, and even more preferably 12.

[0051] In this invention, in step (1), the temperature of the heat treatment is preferably 100-150°C, more preferably 110-140°C, and even more preferably 120-130°C; the time of the heat treatment is preferably 0.5-2h, more preferably 1-2h, and even more preferably 1.5h.

[0052] In this invention, in step (2), the mass ratio of the pretreated sludge to the composite carbon source is preferably 10-20:5-10, more preferably 12-18:6-9, and even more preferably 14-15:7-8.

[0053] In this invention, in step (2), the temperature of the anaerobic fermentation is preferably 35-40°C, more preferably 36-39°C, and even more preferably 37-38°C; the time of the anaerobic fermentation is preferably 15-20 days, more preferably 16-19 days, and even more preferably 17-18 days.

[0054] In this invention, in step (3), the dehydrating agent includes polydimethylsiloxane;

[0055] In this invention, in step (3), the amount of the dewatering agent is preferably 5-10% of the sludge mass, more preferably 6-9%, and even more preferably 7-8%.

[0056] In this invention, in step (4), the drying temperature is preferably 100-120°C, more preferably 105-118°C, and even more preferably 110-115°C; the drying time is preferably 3-4 hours, more preferably 3.5-4 hours, and even more preferably 4 hours.

[0057] In this invention, in step S1, the molar ratio of Ca in the calcium hydroxide suspension to Al in the aluminum chloride suspension is 3:1.

[0058] In this invention, in step S1, the reaction temperature is preferably 20-30°C, more preferably 22-28°C, and even more preferably 25-26°C; the reaction time is preferably 40-60 min, more preferably 45-55 min, and even more preferably 48-50 min.

[0059] In this invention, in step S1, the mass ratio of the hydrotalcite to the chitosan is preferably 5-10:5-10, more preferably 7-9:5-8, and even more preferably 8-9:6-7.

[0060] In this invention, in step S1, the solvent includes water or an aqueous solution of ethanol with a volume fraction preferably of 50-70%, more preferably 55-68%, and even more preferably 60-65%.

[0061] In this invention, in step S1, the heating and drying temperature is preferably 100-120°C, more preferably 105-115°C, and even more preferably 108-110°C; the heating and drying time is preferably 2-3 hours, more preferably 2.5-3 hours, and even more preferably 3 hours.

[0062] In this invention, in step S2, the mass ratio of the composite scaffold material, sodium alginate, peanut cake powder, and wood-rotting fungi is preferably 10-30:15-20:5-10:5-8, more preferably 15-25:16-19:6-9:5.5-7.5, and even more preferably 18-20:17-18:7-8:6-7.

[0063] In this invention, in step S2, the wood-rotting fungi include white-rot fungi and / or brown-rot fungi.

[0064] In this invention, in step S3, the volume ratio of the composite solution to the calcium chloride solution is preferably 1-3:0.5-1.5, more preferably 1.5-2.5:0.6-1.2, and even more preferably 1.8-2:0.8-1.

[0065] In this invention, in step S3, the concentration of the calcium chloride solution is preferably 10-30 wt%, more preferably 15-25 wt%, and even more preferably 18-20 wt%.

[0066] The present invention will be further described in detail below through examples. All raw materials used in the examples are commercially available.

[0067] Example 1

[0068] The preparation method of the composite carbon source includes the following steps:

[0069] S1. Mix calcium hydroxide suspension and aluminum chloride suspension (the molar ratio of Ca in calcium hydroxide suspension and Al in aluminum chloride suspension is 3:1), and react at 25℃ for 40 min to obtain hydrotalcite; mix hydrotalcite, chitosan and water, with a mass ratio of hydrotalcite to chitosan of 6:5, and heat and dry at 120℃ for 3 h to obtain composite scaffold material;

[0070] S2. Mix the composite scaffold material, sodium alginate, peanut cake powder, wood-rotting fungus (white rot fungus), and water. The mass ratio of the composite scaffold material, sodium alginate, peanut cake powder, and wood-rotting fungus is 20:20:10:5. Disperse the mixture to obtain a composite solution.

[0071] S3. Mix the composite solution and a 25wt% calcium chloride solution at a volume ratio of 2:1, and dry them to obtain a composite carbon source;

[0072] The method for sludge purification and conditioning using composite carbon sources includes the following steps:

[0073] (1) After mixing sludge and sodium hydroxide solution, a mixture with a pH value of 10 is obtained. The mixture is then heated at 150°C for 0.5 to 2 hours to obtain pretreated sludge.

[0074] (2) The pretreated sludge and composite carbon source were mixed at a mass ratio of 20:10 and anaerobic fermented at 40°C for 20 days to obtain the treated sludge.

[0075] (3) Add dewatering agent polydimethylsiloxane (the amount of dewatering agent is 10% of the mass of sludge) to the treated sludge, and filter to obtain dewatered sludge;

[0076] (4) Dry the dewatered sludge at 120℃ for 4 hours to complete the sludge purification and conditioning.

[0077] Example 2

[0078] The preparation method of the composite carbon source includes the following steps:

[0079] S1. Mix calcium hydroxide suspension and aluminum chloride suspension (the molar ratio of Ca in calcium hydroxide suspension and Al in aluminum chloride suspension is 3:1), and react at 30℃ for 40 min to obtain hydrotalcite; mix hydrotalcite, chitosan and water, with a mass ratio of hydrotalcite to chitosan of 5:7, and heat and dry at 120℃ for 3 h to obtain composite scaffold material;

[0080] S2. Mix the composite scaffold material, sodium alginate, peanut cake powder, wood-rotting fungus (white rot fungus), and water. The mass ratio of the composite scaffold material, sodium alginate, peanut cake powder, and wood-rotting fungus is 30:20:10:8. Disperse the mixture to obtain a composite solution.

[0081] S3. Mix the composite solution and a 25wt% calcium chloride solution at a volume ratio of 2:1, and dry them to obtain a composite carbon source;

[0082] The method for sludge purification and conditioning using composite carbon sources includes the following steps:

[0083] (1) After mixing the sludge and sodium hydroxide solution, a mixture with a pH value of 10 is obtained. The mixture is then heated at 150°C for 2 hours to obtain pretreated sludge.

[0084] (2) The pretreated sludge and composite carbon source were mixed at a mass ratio of 10:10 and anaerobic fermented at 40°C for 20 days to obtain the treated sludge.

[0085] (3) Add dewatering agent polydimethylsiloxane (the amount of dewatering agent is 8% of the mass of sludge) to the treated sludge, and filter to obtain dewatered sludge;

[0086] (4) Dry the dewatered sludge at 120℃ for 4 hours to complete the sludge purification and conditioning.

[0087] Example 3

[0088] The preparation method of the composite carbon source includes the following steps:

[0089] S1. Mix calcium hydroxide suspension and aluminum chloride suspension (the molar ratio of Ca in calcium hydroxide suspension and Al in aluminum chloride suspension is 3:1) and react at 20℃ for 50 min to obtain hydrotalcite; mix hydrotalcite, chitosan and water, with a mass ratio of hydrotalcite to chitosan of 7:5, and heat and dry at 120℃ for 3 h to obtain composite scaffold material;

[0090] S2. Mix the composite scaffold material, sodium alginate, peanut cake powder, wood-rotting fungus (white rot fungus), and water. The composite scaffold material, sodium alginate, peanut cake powder, and wood-rotting fungus are mixed in a mass ratio of 10:20:10:8 and dispersed to obtain a composite solution.

[0091] S3. Mix the composite solution and a 20wt% calcium chloride solution at a volume ratio of 2:1 and dry them to obtain a composite carbon source;

[0092] The method for sludge purification and conditioning using composite carbon sources includes the following steps:

[0093] (1) After mixing sludge and sodium hydroxide solution, a mixture with a pH value of 10 is obtained. The mixture is then heated at 150°C for 1.5 hours to obtain pretreated sludge.

[0094] (2) The pretreated sludge and composite carbon source were mixed at a mass ratio of 20:5 and anaerobic fermented at 40°C for 20 days to obtain the treated sludge.

[0095] (3) Add dewatering agent polydimethylsiloxane (the amount of dewatering agent is 5% of the mass of sludge) to the treated sludge, and filter to obtain dewatered sludge;

[0096] (4) Dry the dewatered sludge at 120℃ for 4 hours to complete the sludge purification and conditioning.

[0097] Comparative Example 1

[0098] The method for sludge purification and conditioning using a composite carbon source is the same as in Example 1, except that the preparation method of the composite carbon source includes the following steps:

[0099] S1. Mix sodium alginate, peanut cake powder, white rot fungus (a wood-rotting fungus) and water in a mass ratio of 20:10:5 and disperse to obtain a composite solution.

[0100] S2. Mix the composite solution and a 25wt% calcium chloride solution at a volume ratio of 2:1, and then dry them to obtain a composite carbon source.

[0101] Comparative Example 2

[0102] The method for sludge purification and conditioning using a composite carbon source is the same as in Example 1, except that the preparation method of the composite carbon source includes the following steps:

[0103] S1. Mix calcium hydroxide suspension and aluminum chloride suspension (the molar ratio of Ca in calcium hydroxide suspension and Al in aluminum chloride suspension is 3:1), and react at 25℃ for 40 min to obtain hydrotalcite; mix hydrotalcite, chitosan and water, with a mass ratio of hydrotalcite to chitosan of 6:5, and heat and dry at 120℃ for 3 h to obtain composite scaffold material;

[0104] S2. Mix the composite scaffold material, peanut cake powder, wood-rotting fungus (white rot fungus), and water in a mass ratio of 20:10:5. Disperse the mixture and dry it to obtain a composite carbon source.

[0105] Comparative Example 3

[0106] The method for sludge purification and conditioning using a composite carbon source is the same as in Example 1, except that the preparation method of the composite carbon source includes the following steps:

[0107] S1. Mix calcium hydroxide suspension and aluminum chloride suspension (the molar ratio of Ca in calcium hydroxide suspension and Al in aluminum chloride suspension is 3:1), and react at 25℃ for 40 min to obtain hydrotalcite; mix hydrotalcite, chitosan and water, with a mass ratio of hydrotalcite to chitosan of 6:5, and heat and dry at 120℃ for 3 h to obtain composite scaffold material;

[0108] S2. Mix the composite scaffold material, sodium alginate, white rot fungus (a type of wood-rotting fungus), and water in a mass ratio of 20:20:5 and disperse the mixture to obtain a composite solution.

[0109] S3. Mix the composite solution and a 25wt% calcium chloride solution at a volume ratio of 2:1, and then dry them to obtain a composite carbon source.

[0110] Test Example 1

[0111] The gases produced during the anaerobic fermentation process in the above embodiments and comparative examples were tested, and the conversion rate of volatile fatty acids was obtained from the test results, as shown in Table 1.

[0112] The heavy metal concentration of the sludge that underwent sludge purification treatment in the above embodiments and comparative examples was tested, and the test results are shown in Table 1.

[0113] Table 1

[0114]

[0115] Table 1 shows that the preparation method of the composite carbon source has a significant impact on the sludge treatment effect. The preparation method in the examples involved a rational combination and compounding of various components such as hydrotalcite, chitosan, sodium alginate, peanut meal, and white-rot fungi, forming a composite material with a porous structure and good adsorption performance. This effectively promotes the removal of heavy metals and the degradation of organic matter in the sludge. In the comparative examples, the lack of certain key components (such as hydrotalcite, chitosan, sodium alginate, or peanut meal) resulted in an incomplete structure and function of the composite carbon source, significantly reducing its purification and conditioning effect on the sludge, especially in terms of heavy metal removal and organic matter degradation. This composite carbon source, through the synergistic effect of multiple substances, can not only effectively reduce the heavy metal content in the sludge but also significantly improve the conversion rate of organic matter in the sludge. It has advantages such as high efficiency, environmental friendliness, and economy, providing an effective solution for the resource utilization and harmless treatment of sludge.

[0116] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for sludge purification and conditioning using a composite carbon source, characterized in that, Includes the following steps: (1) After mixing the sludge and alkaline solution, a mixture is obtained and then heated to obtain pretreated sludge; (2) The pretreated sludge and composite carbon source are mixed and anaerobic fermentation is carried out to obtain the treated sludge; (3) Add a dewatering agent to the treated sludge and filter it to obtain dewatered sludge; (4) Dry the dewatered sludge to complete the sludge purification and conditioning process; The method for preparing the composite carbon source includes the following steps: S1. Mix calcium hydroxide suspension and aluminum chloride suspension and react to obtain hydrotalcite; mix hydrotalcite, chitosan and solvent, and heat and dry to obtain composite scaffold material; S2. Mix the composite scaffold material, sodium alginate, peanut cake powder, wood-decaying fungi, and water, and disperse them to obtain a composite solution; S3. Mix the composite solution and the calcium chloride solution to obtain a composite carbon source.

2. The method for sludge purification and conditioning using a composite carbon source according to claim 1, characterized in that, In step (1), the alkaline solution includes at least one of potassium hydroxide solution, sodium hydroxide solution and calcium hydroxide solution; In step (1), the pH of the mixture is 9 to 13; In step (1), the temperature of the heat treatment is 100-150°C and the time of the heat treatment is 0.5-2h.

3. The method for sludge purification and conditioning using a composite carbon source according to claim 1, characterized in that, In step (2), the mass ratio of the pretreated sludge to the composite carbon source is 10-20:5-10; In step (2), the temperature of the anaerobic fermentation is 35-40℃, and the time of the anaerobic fermentation is 15-20 days.

4. The method for sludge purification and conditioning using a composite carbon source according to claim 1, characterized in that, In step (3), the dehydrating agent includes polydimethylsiloxane; In step (3), the amount of the dewatering agent used is 5 to 10% of the sludge mass.

5. The method for sludge purification and conditioning using a composite carbon source according to claim 1, characterized in that, In step (4), the drying temperature is 100-120°C and the drying time is 3-4 hours.

6. The method for sludge purification and conditioning using a composite carbon source according to claim 1, characterized in that, In step S1, the molar ratio of Ca in the calcium hydroxide suspension to Al in the aluminum chloride suspension is 3:1; In step S1, the reaction temperature is 20–30°C, and the reaction time is 40–60 min.

7. The method for sludge purification and conditioning using a composite carbon source according to claim 1, characterized in that, In step S1, the mass ratio of the hydrotalcite to the chitosan is 5-10:5-10; In step S1, the solvent includes water or an aqueous solution of ethanol with a volume fraction of 50-70%.

8. The method for sludge purification and conditioning using a composite carbon source according to claim 1, characterized in that, In step S1, the heating and drying temperature is 100-120°C, and the heating and drying time is 2-3 hours.

9. The method for sludge purification and conditioning using a composite carbon source according to claim 1, characterized in that, In step S2, the mass ratio of the composite scaffold material, sodium alginate, peanut cake powder, and wood-decaying fungi is 10-30:15-20:5-10:5-8; In step S2, the wood-rotting fungi include white-rot fungi and / or brown-rot fungi.

10. The method for sludge purification and conditioning using a composite carbon source according to claim 1, characterized in that, In step S3, the volume ratio of the composite solution to the calcium chloride solution is 1-3:0.5-1.5; In step S3, the concentration of the calcium chloride solution is 10–30 wt%.

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