Sludge degradation composite bacteria, and preparation method and application thereof

Abstract

The application discloses sludge degradation composite bacteria and a preparation method and application thereof, and belongs to the technical field of sludge degradation; the composite bacteria comprises 10-25 parts of pseudomonas aeruginosa, 15-30 parts of bacillus subtilis, 10-20 parts of yeast, 5-15 parts of trichoderma harzianum, 5-10 parts of nitrifying bacteria and 10-20 parts of aspergillus niger; the preparation method is as follows: the pseudomonas aeruginosa, the bacillus subtilis, the yeast, the trichoderma harzianum, the nitrifying bacteria and the aspergillus niger are respectively cultured in culture media to obtain pseudomonas aeruginosa liquid bacterial species, bacillus subtilis liquid bacterial species, yeast liquid bacterial species, trichoderma harzianum liquid bacterial species, nitrifying bacteria liquid bacterial species and aspergillus niger liquid bacterial species; then the various liquid bacterial species are respectively matured, and then the matured bacterial species are mixed to obtain the first composite bacteria; by adding the composite bacteria into sludge, heavy metals and indole in the sludge can be effectively removed.

Description

Technical Field

[0001] This invention relates to the field of sludge degradation technology, and in particular to a sludge-degrading composite bacteria, its preparation method, and its application. Background Technology

[0002] Urban sewage is a mixture of wastewater from residential and industrial production, groundwater, and rainwater. During sewage purification, a highly water-rich biomass waste, known as sludge, is generated, existing in a state between solid and liquid. Industrial wastewater, including coking wastewater, dye wastewater, pharmaceutical wastewater, and pesticide wastewater, contains large amounts of nitrogen-containing heterocyclic compounds such as pyrrole, indole, pyridine, quinoline, isoquinoline, and their derivatives. Consequently, urban sludge contains a significant amount of these nitrogen-containing heterocyclic compounds. These compounds have conjugated systems, making them difficult to break down during metabolism and exhibiting poor biodegradability. Furthermore, many of these substances have carcinogenic, teratogenic, and mutagenic effects, posing serious threats to the environment and human health. Indole, a typical nitrogen-containing heterocyclic organic compound, possesses a strong fecal odor at high concentrations, with strong and persistent diffusion and high biotoxicity. Therefore, effectively degrading indole is crucial in the treatment of urban sludge. Summary of the Invention

[0003] This application aims to overcome the shortcomings of the prior art by providing a sludge-degrading composite bacteria, its preparation method, and its application, so as to at least achieve the purpose of effectively degrading indole in sludge.

[0004] The above-mentioned technical objective of the present invention is achieved through the following technical solution:

[0005] A sludge-degrading composite microbial agent, comprising a first composite microbial agent, wherein the first composite microbial agent comprises the following components in parts by weight:

[0006] 10–25 parts of Pseudomonas aeruginosa, 15–30 parts of Bacillus subtilis, 10–20 parts of yeast, 5–15 parts of Trichoderma harzianum, 5–10 parts of nitrifying bacteria and 10–20 parts of Aspergillus niger.

[0007] In the above scheme, *Pseudomonas aeruginosa* can increase the solubility and degrade indole, improving the removal efficiency of indole from sludge; *Bacillus subtilis* has a strong ability to decompose carbon-based, phosphorus-based, and sulfur-based pollutants, as well as proteins and complex polysaccharides, and also plays an important role in the decomposition of water-soluble organic matter; yeast, a typical facultative anaerobic bacterium, can improve the adaptability of the compound bacteria to aerobic and anaerobic environments, and can improve the decomposition of organic matter and the removal of harmful substances in anaerobic processes. Simultaneously, yeast can effectively adsorb heavy metals in sludge, thereby reducing the inhibition rate of heavy metals on the removal of indole by the compound bacteria; *Trichoderma harzianum* can decompose organic matter, fiber, and protein; nitrifying bacteria can oxidize ammonia nitrogen compounds to nitrates, reducing the generation of nitrites and ammonia, and reducing the odor of sludge; *Aspergillus niger* can synergistically enhance the removal of organic matter from sludge. The first compound bacteria obtained by combining the above-mentioned bacteria can effectively degrade organic matter in sludge, especially indole.

[0008] Preferably, the first compound bacteria comprises the following components in parts by weight:

[0009] 13–20 Pseudomonas aeruginosa, 20–25 Bacillus subtilis, 13–18 yeasts, 8–13 Trichoderma harzianum, 7–9 nitrifying bacteria, and 12–17 Aspergillus niger.

[0010] Preferably, the first compound bacteria comprises the following components in parts by weight:

[0011] 17 samples of Pseudomonas aeruginosa, 23 samples of Bacillus subtilis, 15 samples of yeast, 12 samples of Trichoderma harzianum, 8 samples of nitrifying bacteria, and 16 samples of Aspergillus niger.

[0012] Preferably, the density of the first compound bacteria is 10. 7 ~10 8 CFU / mL.

[0013] Preferably, the degradation temperature of the first composite bacteria is 25-35°C; the degradation pH of the first composite bacteria is 6.3-7.8.

[0014] Preferably, the sludge-degrading composite bacteria further includes a second composite bacteria, which includes NaS2O3·5H2O, FeSO4·7H2O, sulfur powder, ferrous thiobacillus, and thiobacillus sulfooxidans.

[0015] In the above scheme, when the first compound bacteria degrade the sludge, the heavy metals in the sludge will inhibit the first compound bacteria to varying degrees, resulting in a decrease in the efficiency of the first compound bacteria in degrading the sludge and making it difficult to achieve the best effect. On this basis, by adding the second compound bacteria to the sludge in advance, the heavy metals in the sludge can be effectively removed, thereby greatly improving the degradation efficiency of the first compound bacteria on indole due to the reduced heavy metal content.

[0016] Preferably, the ratio (m:m:m:v:v) of NaS2O3·5H2O, FeSO4·7H2O, sulfur powder, ferrous thiobacillus and thiobacillus is 0.2-0.3:0.2-0.3:0.005-0.008:1-1.8:1-1.8.

[0017] Preferably, the sludge has a water content of 65-90%, a density of 1011.96 g / L-1302.07 g / L, and an indole concentration of 50-300 mg / L; per kilogram of dry sludge, the sludge contains 500-6000 mg of Cu, 800-4000 mg of Zn, 300-1500 mg of Mn, 100-300 mg of Cr, and 1-200 mg of Cd.

[0018] In the above scheme, by further limiting the water content, density, indole content, and heavy metal content of the sludge, it is possible to make it suitable for the dosage of the first and second compound bacteria, so as to achieve the best effect of degrading indole and removing heavy metals.

[0019] Furthermore, to achieve the above objectives, the present invention also provides a method for preparing a compound bacteria, wherein the method for preparing the first compound bacteria includes the following steps:

[0020] S1 After purifying and rejuvenating the Pseudomonas aeruginosa, Bacillus subtilis, yeast, Trichoderma harzianum, nitrifying bacteria and Aspergillus niger respectively, they were cultured in culture media to obtain liquid strains of Pseudomonas aeruginosa, Bacillus subtilis, yeast, Trichoderma harzianum, nitrifying bacteria and Aspergillus niger.

[0021] S2 involves maturing the liquid cultures of Pseudomonas aeruginosa, Bacillus subtilis, yeast, Trichoderma harzianum, nitrifying bacteria, and Aspergillus niger, and then mixing the matured cultures to obtain the first composite bacteria.

[0022] In addition, to achieve the above objectives, the present invention also provides the application of the above-mentioned sludge-degrading composite bacteria in the degradation of indole.

[0023] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0024] 1. The first compound bacteria obtained by combining Pseudomonas aeruginosa, Bacillus subtilis, yeast, Trichoderma harzianum, nitrifying bacteria and Aspergillus niger can effectively degrade organic matter in sludge, especially indole, and its indole removal rate in sludge can reach 81%.

[0025] 2. By adding the second compound bacteria, heavy metals in the sludge can be effectively removed in advance before the first compound bacteria are used, thereby improving the efficiency of the first compound bacteria in degrading organic matter and increasing the removal rate of indole; through the combined action of the first and second compound bacteria, the removal rate of indole in the sludge can reach 96.8%.

[0026] 3. In preparing the first compound bacteria, by culturing each strain separately before mixing them, the antagonistic effect of multiple strains culturing together can be avoided, which may cause some strains to die, and the synergistic effect between strains can be improved. Detailed Implementation

[0027] The technical solutions in the embodiments of this application will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0028] Example 1

[0029] 1. Preparation of the first compound bacteria

[0030] S1 first purified and rejuvenated Pseudomonas aeruginosa, Bacillus subtilis, yeast, and nitrifying bacteria. Then, the purified and rejuvenated Pseudomonas aeruginosa, Bacillus subtilis, yeast, and nitrifying bacteria were cultured in a first culture medium of 500–1000 g to obtain liquid cultures of Pseudomonas aeruginosa, Bacillus subtilis, yeast, and nitrifying bacteria. The culture temperature was 30℃, and the shaking incubation time was 65 h. The first culture medium (by weight percentage) was prepared from 2.5% amino acids, 2% potassium dihydrogen phosphate, 1% glucose, 0.8% peptone, 0.7% urea, 1% beef extract, and water.

[0031] S2 first purified and rejuvenated *Trichoderma harzianum* and *Aspergillus niger*, then cultured the purified and rejuvenated *Trichoderma harzianum* and *Aspergillus niger* in a second culture medium of 500–1000 g to obtain liquid strains of *Trichoderma harzianum* and *Aspergillus niger*. The culture temperature was 28–35℃, and the shaking culture time was 58–72 h. The second culture medium (by weight percentage) was prepared from 0.35% potassium nitrate, 0.15% sodium chloride, 5% molasses, 2% glucose, and water.

[0032] S3. Place the liquid cultures of Pseudomonas aeruginosa, Bacillus subtilis, yeast, Trichoderma harzianum, nitrifying bacteria, and Aspergillus niger into seed tanks respectively, and incubate them at 30°C for 8-10 days until maturation is complete.

[0033] S4 is obtained by mixing 25 portions of matured Pseudomonas aeruginosa liquid culture, 15 portions of Bacillus subtilis liquid culture, 10 portions of yeast liquid culture, 15 portions of Trichoderma harzianum liquid culture, 6 portions of nitrifying bacteria liquid culture, and 18 portions of Aspergillus niger liquid culture from S3 to obtain the first compound bacteria. The density of the first compound bacteria is 10. 7 CFU / mL.

[0034] 2. The second compound bacteria consisted of 0.22g NaS2O3·5H2O, 0.23g FeSO4·7H2O, 0.006g sulfur powder, 1.3ml ferrous thiobacillus and 1.3ml thiobacillus sulfur.

[0035] The preparation method of *Thiobacillus ferrooxidans* is an existing technology, as detailed below:

[0036] S1 After filtering the sludge, 10 ml of the filtrate was added to an Erlenmeyer flask containing 40 ml of 9K liquid medium. The flask was placed in an air bath constant temperature shaker and cultured at 150 rpm and 30°C for 8-10 days. Then, 10 ml of the supernatant was added to 60 ml of 9K liquid medium and cultured under the same conditions. This process was repeated 4 times. Afterward, the bacterial culture was spread on 9K solid medium and cultured in a biochemical incubator at 30°C for 10 days. Then, a single colony with growth advantage was picked and inoculated into a test tube containing 10 mL of 9K liquid medium. The tube was placed in an air bath constant temperature shaker and cultured at 150 rpm and 30°C. This culture process was repeated 3 times to obtain a relatively pure strain of *Thiobacillus ferrooxidans*, which was identified as *Thiobacillus ferrooxidans*.

[0037] The preparation of 9K liquid culture medium (1L) was as follows: 44.3g of FeSO4·7H2O was dissolved in 250ml of distilled water, stirred evenly, and the pH was adjusted to 2.0 with sulfuric acid. The solution was then filtered through a 0.22µm microporous membrane for sterilization and set aside. 3g of (NH4)2SO4, 0.5g of K2HPO4, 0.1g of KCl, 0.5g of MgSO4·7H2O, and 0.01g of Ca(NO3)2 were dissolved in 750ml of distilled water, stirred evenly, and the pH was adjusted to 2.0 with sulfuric acid. The solution was plugged with cotton, wrapped in kraft paper, and autoclaved at 121℃ for 15min. Then, 250ml of the filtered and sterilized FeSO4·7H2O solution was added, and the mixture was shaken well and set aside.

[0038] Preparation of 9K solid culture medium (1L): Dissolve 3g of (NH4)2SO4, 0.5g of K2HPO4, 0.1g of KCl, 0.5g of MgSO4·7H2O, and 0.01g of Ca(NO3)2 in 1L of distilled water to prepare a basic salt solution. Adjust the pH to approximately 2.8 with sulfuric acid and shake well. The preparation is divided into three parts: A, B, and C. Take 300ml of the prepared basic salt solution, add 15g of agar to dissolve, and pour into an Erlenmeyer flask. B. Take another 250ml of the basic salt solution, weigh 44.3g of FeSO4·7H2O, dissolve it in the basic salt solution, and filter sterilize using a 0.22µm microporous membrane. C. Pour the remaining basic salt solution into a 1L Erlenmeyer flask, plug it with cotton, and wrap it with kraft paper. Autoclave AC at 121℃ for 15 minutes, then remove and cool in a 55℃ constant temperature water bath. When the temperature of C drops to 80℃, quickly add B and mix thoroughly, then add A and mix evenly. When the temperature of this culture medium drops to 55℃, pour it into plates, adding about 15ml of culture medium to each plate.

[0039] The preparation method of Thiobacillus oxidans is an existing technology, as detailed below:

[0040] After filtering the sludge, take 10 ml of the filtrate and inoculate it into a 250 ml Erlenmeyer flask containing 100 ml of sterile Waksman medium. Incubate at 30°C and 150 rpm in a shaker for 7-10 days, until the medium turns cloudy and milky white. Transfer 10 ml of this solution to fresh Waksman medium. Repeat this process for four or five generations of enrichment. Then, transfer 1 ml of the enriched bacterial solution to a test tube containing 9 ml of sterile water. Shake well, then transfer 1 ml of this solution to a 9 ml sterile water test tube. Repeat this process to dilute the bacterial solution to a 10:1 ratio. -1 10 -2 10 -3 10 -4 10 -5 10 -6 A dilution solution of the concentration. Take 10... -4 10 -5 10 -6 Three concentrations of dilution, 0.2 ml each, were inoculated onto different Starky-Na2S2O4 substrates. 3－ Spread the Starky-Na2S2O solution evenly onto agar solid medium using a spreader. Repeat this process three times for each concentration. Record the results on the petri dishes. After incubating at room temperature for 2 hours, incubate upside down in a 30°C incubator for 7–10 days. Afterward, use a toothpick to separate the Starky-Na2S2O solution. 3－Small colonies appearing on agar solid medium were picked up and inoculated into a small conical flask containing 10 mL of basal medium. The flask was sealed with gauze and incubated until the liquid in the small conical flask (test tube) turned milky white and uniformly turbid. The above operation was repeated for repeated isolation and purification, and finally a superior sulfur-oxidizing strain was isolated, which was identified as *Thiobacillus thiooxidans*.

[0041] The Waksman medium consisted of: (NH4)2SO4 0.2 g, K2HPO4·3H2O 3.0 g, MgSO4·7H2O 0.5 g, CaCl2·2H2O 0.126 g, sulfur 10.0 g, distilled water 1000 mL, pH = 2.0.

[0042] Starky-Na2S2O 3－ The agar medium composition is as follows: (NH4)2SO4 2.0g, MgSO4·7H2O 0.5g, CaCl2·2H2O 0.25g, KH2PO4 3.0g, FeSO4·7H2O 0.001g, Na2S2O3 10g, agar 3.0g, distilled water 1000mL;

[0043] The basic culture medium consisted of: (NH4)2SO4 0.2g, K2HPO4·3H2O 3.0g, MgSO4·7H2O 0.5g, CaCl2·2H2O 0.126g, and 1000mL of distilled water, pH=2.0.

[0044] The parameters of the sludge are as follows: water content is 90%, density is 1111.02 g / L, indole concentration in sludge is 200.4 mg / L; Cu content is 2300 mg, Zn content is 1000.78 mg, Mn content is 590.2 mg, Cr content is 239.2 mg, and Cd content is 2.9 mg per kilogram of dry sludge. The heavy metal content was obtained by analyzing the sample after drying it to constant weight at 95–110℃.

[0045] Example 2

[0046] 1. Preparation of the first compound bacteria

[0047] S1 first purified and rejuvenated Pseudomonas aeruginosa, Bacillus subtilis, yeast, and nitrifying bacteria. Then, the purified and rejuvenated Pseudomonas aeruginosa, Bacillus subtilis, yeast, and nitrifying bacteria were cultured in a first culture medium of 500–1000 g to obtain liquid cultures of Pseudomonas aeruginosa, Bacillus subtilis, yeast, and nitrifying bacteria. The culture temperature was 33℃, and the shaking incubation time was 70 h. The first culture medium (by weight percentage) was prepared from 2.5% amino acids, 1.5% potassium dihydrogen phosphate, 1.5% glucose, 0.1% peptone, 0.7% urea, 1% beef extract, and water.

[0048] S2 first purified and rejuvenated *Trichoderma harzianum* and *Aspergillus niger*, then cultured the purified and rejuvenated *Trichoderma harzianum* and *Aspergillus niger* in a second culture medium of 500–1000 g to obtain liquid strains of *Trichoderma harzianum* and *Aspergillus niger*. The culture temperature was 28–35℃, and the shaking culture time was 58–72 h. The second culture medium (by weight percentage) was prepared from 0.5% potassium nitrate, 0.2% sodium chloride, 5% molasses, 2% glucose, and water.

[0049] S3. Place the liquid cultures of Pseudomonas aeruginosa, Bacillus subtilis, yeast, Trichoderma harzianum, nitrifying bacteria, and Aspergillus niger into seed tanks respectively, and incubate them at 25-35℃ for 5-10 days until maturation is complete.

[0050] S4 is obtained by mixing 14 portions of matured Pseudomonas aeruginosa liquid culture, 20 portions of Bacillus subtilis liquid culture, 18 portions of yeast liquid culture, 13 portions of Trichoderma harzianum liquid culture, 9 portions of nitrifying bacteria liquid culture, and 12 portions of Aspergillus niger liquid culture from S3 to obtain the first compound bacteria.

[0051] 2. The second compound bacteria consist of 0.25g NaS2O3·5H2O, 0.23g FeSO4·7H2O, 0.007g sulfur powder, 1.5ml Thiobacillus ferrooxidans, and 1.5ml Thiobacillus thiooxidans; wherein, the other parameters and steps in the preparation methods of Thiobacillus ferrooxidans and Thiobacillus thiooxidans are the same as in Example 1.

[0052] Example 3

[0053] 1. Compared with Example 1, the weight proportions of each bacterial species in the first compound bacteria have been changed. The weight proportions of each bacterial species after the change are as follows: 17 parts of Pseudomonas aeruginosa liquid culture, 23 parts of Bacillus subtilis liquid culture, 15 parts of yeast liquid culture, 12 parts of Trichoderma harzianum liquid culture, 8 parts of nitrifying bacteria liquid culture and 16 parts of Aspergillus niger liquid culture;

[0054] The other parameters and steps in the preparation method of the first compound bacteria are the same as in Example 1.

[0055] 2. The second compound bacteria consisted of 0.24g NaS2O3·5H2O, 0.26g FeSO4·7H2O, 0.006g sulfur powder, 1.4ml Thiobacillus ferrooxidans, and 1.2ml Thiobacillus thiooxidans; wherein the preparation methods of Thiobacillus ferrooxidans and Thiobacillus thiooxidans were the same as in Example 1.

[0056] Example 4

[0057] Compared to Example 1, the preparation method of the first compound bacteria is the same as that in Example 1;

[0058] Compared to Example 1, the sludge parameters used in the preparation method of the inoculum in the second compound bacteria have been changed. The changed parameters are as follows:

[0059] The sludge has a water content of 85%, a density of 1211.7 g / L, and an indole concentration of 230.2 mg / L. Each kilogram of dry sludge contains 2100 mg of Cu, 2000.3 mg of Zn, 500.2 mg of Mn, 245 mg of Cr, and 3.4 mg of Cd.

[0060] Comparative Example 1

[0061] 1. Compared with Example 1, the types of bacteria in the first compound bacteria have been changed. The types and weights of each bacteria after the change are as follows: 25 parts of Pseudomonas aeruginosa liquid culture, 15 parts of Bacillus subtilis liquid culture, 15 parts of Trichoderma harzianum liquid culture, and 6 parts of nitrifying bacteria liquid culture.

[0062] 2. The second compound bacteria is the same as in Example 1.

[0063] Comparative Example 2

[0064] 1. Compared with Example 1, the types of bacteria in the first compound bacteria have been changed. The types and weight parts of each bacteria after the change are as follows: 10 parts of yeast liquid culture, 6 parts of nitrifying bacteria liquid culture and 18 parts of Aspergillus niger liquid culture;

[0065] 2. The second compound bacteria is the same as in Example 1.

[0066] Comparative Example 3

[0067] 1. The preparation method of the first compound bacteria is the same as in Example 1;

[0068] 2. The dosage of the second compound bacteria has been changed. The revised formula for the second compound bacteria is as follows:

[0069] The second compound bacteria consisted of 0.7g NaS2O3·5H2O, 0.8g FeSO4·7H2O, 0.006g sulfur powder, 1.3ml ferrous thiobacillus, and 1.3ml thiobacillus sulfur.

[0070] Experimental Example

[0071] The first and second composite bacteria from Examples 1-4 and Comparative Example 1 were applied to sludge treatment. The specific experimental procedures are as follows:

[0072] Experimental Example 1: When the first compound bacteria and the second compound bacteria are used together.

[0073] The second compound bacteria (all added) and 10 mL of sludge were added to a 250 mL Erlenmeyer flask, followed by distilled water to 200 mL. The leaching experiment was conducted for 10 days at 32 °C with a stirring speed of 120 r / min. After the leaching experiment, excess liquid in the Erlenmeyer flask was filtered off, and then deionized water was added to make the sludge moisture content 85%. The first compound bacteria (6% of the sludge dry weight) were added, and the pH of the solution was adjusted to 7. The solution was then treated at 37 °C and 150 r / min on a shaker for 48 h. After treatment, the indole concentration in the sludge was measured.

[0074] Experimental Example 2: Using only the first compound bacteria.

[0075] 10 mL of sludge was added to a 250 mL Erlenmeyer flask, followed by distilled water to a final volume of 200 mL. A leaching experiment was conducted for 10 days at 32 °C with a stirring speed of 120 r / min. After the leaching experiment, excess liquid in the Erlenmeyer flask was filtered off. Deionized water was then added to bring the sludge moisture content to 85%, and 6% of the dry weight of the first compound bacteria was added. The pH of the solution was then adjusted to 7, and the mixture was treated on a shaker at 37 °C and 150 r / min for 48 h. The concentration of indole in the sludge was then measured after treatment.

[0076] The indole content after final treatment in Examples 1-4 and Comparative Examples 1-3 is recorded in Table 1.

[0077]

[0078] Note: Since the change in Comparative Example 2 is the second compound bacteria, no additional experiment is needed if only the first compound bacteria are used.

[0079] Table 1 shows that when the first and second compound bacteria in Examples 1-4 are used together, the concentration of indole in the sludge can be greatly reduced. While using the first compound bacteria alone can effectively reduce indole content, the reduction is less significant compared to using both compound bacteria together. This is because heavy metals in the sludge inhibit the first compound bacteria. The second compound bacteria leaching out the heavy metals significantly reduces the heavy metal content in the sludge, thus reducing the inhibition on the first compound bacteria and improving the efficiency of the second compound bacteria in removing indole. In Comparative Examples 1 and 2, the first compound bacteria were not prepared according to the formulation ratio in this invention, resulting in a reduced effect on indole degradation. In Comparative Example 3, when too much NaS₂O₃·5H₂O was added, thiosulfate ions, acting as heavy metal ligands, would react with heavy metal ions such as Cu. + Zn 2 + The formation of stable complexes reduces the leaching rate. At the same time, the addition of excessive ferrous ions leads to an increase in the concentration of ferric ions, which can be partially converted into ferric ammonium in the air. This can inhibit the growth of TF, thereby reducing the leaching efficiency of the first complex bacteria on metals and affecting the removal rate of indole by the second complex bacteria.

[0080] Furthermore, by measuring the heavy metal content of the turbid liquid after leaching experiments in Examples 1-4, the leaching rates of Cu, Zn, Mn, Cr, and Cd were determined to be 85-90%, 82-92%, 75-80%, 75-80%, and 70-80%, respectively. This indicates that the second composite bacteria in this invention can significantly reduce the heavy metal content in sludge and assist the first composite bacteria in degrading organic matter, especially indole.

[0081] The above are merely preferred embodiments of the present invention. It should be understood that the present invention is not limited to the forms disclosed herein and should not be construed as excluding other embodiments. It can be used in various other combinations, modifications, and environments, and can be modified within the scope of the present invention through the above teachings or related technologies or knowledge. Modifications and variations made by those skilled in the art that do not depart from the spirit and scope of the present invention should be within the protection scope of the appended claims.

Claims

1. A sludge-degrading composite bacteria, characterized in that, It includes a first compound bacteria, which comprises the following components in parts by weight: 10–25 parts of Pseudomonas aeruginosa, 15–30 parts of Bacillus subtilis, 10–20 parts of yeast, 5–15 parts of Trichoderma harzianum, 5–10 parts of nitrifying bacteria, and 10–20 parts of Aspergillus niger; The sludge contains heavy metals Cu, Zn, Mn, Cr, and Cd.

2. The sludge-degrading composite bacteria according to claim 1, characterized in that, The first compound bacteria comprises the following components in parts by weight: 13-20 parts of Pseudomonas aeruginosa, 20-25 parts of Bacillus subtilis, 13-18 parts of yeast, 8-13 parts of Trichoderma harzianum, 7-9 parts of nitrifying bacteria and 12-17 parts of Aspergillus niger.

3. The sludge-degrading composite bacteria according to claim 1, characterized in that, The first compound bacteria comprises the following components in parts by weight: 17 samples of Pseudomonas aeruginosa, 23 samples of Bacillus subtilis, 15 samples of yeast, 12 samples of Trichoderma harzianum, 8 samples of nitrifying bacteria, and 16 samples of Aspergillus niger.

4. The sludge-degrading composite bacteria according to any one of claims 1 to 3, characterized in that, The density of the first compound bacteria is 10. 7 ~10 8 CFU / mL.

5. A sludge-degrading composite bacteria according to any one of claims 1 to 3, characterized in that, The degradation temperature of the first compound bacteria is 25–35°C; the degradation pH of the first compound bacteria is 6.3–7.

8.

6. The sludge-degrading composite bacteria according to claim 1, characterized in that, It also includes a second complex of bacteria, which includes NaS2O3·5H2O, FeSO4·7H2O, sulfur powder, ferrous thiobacillus, and thiobacillus thiooxidans.

7. The sludge-degrading composite bacteria according to claim 6, characterized in that, The ratio (m:m:m:v:v) of NaS2O3·5H2O, FeSO4·7H2O, sulfur powder, ferrous thiobacillus and thiobacillus is 0.2~0.3:0.2~0.3:0.005~0.008:1~1.8:1~1.

8.

8. A sludge-degrading composite bacteria according to claim 6 or 7, characterized in that, The sludge has a water content of 65-90%, a density of 1011.96 g / L-1302.07 g / L, and an indole concentration of 50-300 mg / L. Each kilogram of dry sludge contains 500-6000 mg Cu, 800-4000 mg Zn, 300-1500 mg Mn, 100-300 mg Cr, and 1-200 mg Cd.

9. A method for preparing a sludge-degrading composite bacteria according to any one of claims 1 to 3, characterized in that, The preparation method of the first compound bacteria includes the following steps: S1 After purifying and rejuvenating the Pseudomonas aeruginosa, Bacillus subtilis, yeast, Trichoderma harzianum, nitrifying bacteria and Aspergillus niger respectively, they were cultured in culture media to obtain liquid strains of Pseudomonas aeruginosa, Bacillus subtilis, yeast, Trichoderma harzianum, nitrifying bacteria and Aspergillus niger. S2 involves maturing the liquid cultures of Pseudomonas aeruginosa, Bacillus subtilis, yeast, Trichoderma harzianum, nitrifying bacteria, and Aspergillus niger, and then mixing the matured cultures to obtain the first composite bacteria.

10. The application of the sludge-degrading composite bacteria according to any one of claims 1-3 and 6 in the degradation of indole.

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