A novel biological flocculation and cell disruption pretreatment method for sludge based on Paenibacillus polymyxa

Abstract

The present invention provides a novel biological flocculation and cell disruption pretreatment method for sludge based on Paenibacillus polymyxa, which comprises the following steps: S01: preparing a Paenibacillus polymyxa bacterial agent with high-efficiency sludge flocculation and cell disruption effects; S02: putting the above-mentioned Paenibacillus polymyxa bacterial agent into the sludge to be dehydrated pretreated for biological flocculation-coupled cell disruption reaction; Paenibacillus polymyxa, as a biological flocculant and antibacterial substance-producing bacterium with extremely strong stress resistance, has the characteristic of rupturing cells by lysing the cell membranes of bacteria or the cell walls of fungi. It has broad-spectrum antibacterial properties, can lyse most bacteria and fungi in the sludge, and further destroy the sludge floc structure, which helps to release the intracellular bound water. In addition, the macromolecular biological flocculation active organic substances produced by Paenibacillus polymyxa can promote sludge flocculation and efficiently achieve sludge-water separation, thereby further improving the sludge dehydration pretreatment effect.

Description

Technical Field

[0001] The present invention relates to a novel sludge bioflocculation and cell disruption pretreatment method based on Paenibacillus polymyxa, belonging to the technical field of sludge biological pretreatment. Background Art

[0002] The activated sludge biological purification technology commonly used in sewage treatment plants inevitably results in the generation of a large amount of excess sludge with a water content of over 95% and accounting for 0.15% - 1% of the treated water volume. Deep dewatering treatment of sludge is a necessary front-end operation to reduce the water content and volume of sludge and achieve harmless, stable, and resourceful treatment and disposal of sludge. Currently, the sewage treatment plants generally adopt the sludge deep dewatering method of combining chemical conditioners with high-pressure mechanical filtration. This method has high treatment costs and unsatisfactory dewatering effects. In addition, the addition of chemical agents will increase the inorganic content of sludge and reduce the calorific value of sludge, which is not conducive to the subsequent treatment and disposal of sludge. Therefore, pretreatment of sludge to condition and modify it to improve the sludge dewatering performance is an important front-end operation to improve the efficiency of sludge deep dewatering and reduce the water content of sludge.

[0003] The water in sludge is mainly divided into free water, interstitial water, surface adsorbed water, and bound water. Among them, free water and interstitial water are easily separated, and partial removal can be achieved by physical pressure; while surface adsorbed water and bound water are difficult to remove by the action of mechanical force. Among them, internal bound water refers to the water inside sludge particles and microbial cells, and it must rely on destroying the sludge and microbial cell structures to be removed. Currently, the commonly used sludge conditioning and modification pretreatment methods include physical, chemical, and biological methods. Physical pretreatment methods include ultrasound, microwave, electrodialysis, etc. Although these technologies can partially reduce the dosage of chemical conditioners before sludge dewatering, they generally have defects such as high energy consumption, complex equipment, and high maintenance costs. Chemical methods include oxidation method, thermal acid-base method, uncoupling method, etc. However, these technologies generally increase the cost of chemical agent addition, have complex process control, or will change the properties of sludge, such as the need to re-neutralize the treated sludge, and will bring the problem of secondary pollution. Biological methods include aerobic and anaerobic digestion of sludge, ingestion by micro-animals, and addition of lytic enzymes, antibiotics, etc. Compared with the first two methods, the biological treatment of sludge has a greater degree of damage to the rigid cell membrane structure that hinders cell lysis, can effectively help release the intracellular water, bound water, and interstitial water that are difficult to remove in sludge, and is energy-saving and low-consumption without producing secondary pollution. Therefore, the sludge biological pretreatment dewatering technology, as an ecological engineering technology with low energy consumption and no secondary pollution, has been increasingly concerned.

[0004] Paenibacillus polymyxa (P. polymyxa) is a spore-forming Gram-positive bacterium. Its 16S rRNA sequence has a high degree of specificity, so it is classified into the genus Paenibacillus Ash. Currently, 23 species have been discovered, and P. polymyxa is its type species. Under the microscope, P. polymyxa is rod-shaped, with a thick spore wall and motile by peritrichous flagella. As a non-pathogenic microorganism widely present in nature, P. polymyxa has the characteristics of fast growth, simple nutrition, and the ability to form spores with extremely strong stress resistance, and can be isolated from soil, sewage, livestock and poultry manure and other matrices. In addition, the genus Paenibacillus generally has resistance to environmental stress, can grow in relatively extreme environments, and the prepared microbial inoculum has a long storage time.

[0005] Paenibacillus polymyxa can produce various antibacterial substances such as peptides, proteins, nucleosides, pyrazines and phenols, which can act on the bacterial cell membrane or fungal cell wall, causing cell rupture and cell death, thereby contributing to the release of intracellular bound water. In addition, some studies have also proved that its live bacteria itself can directly inhibit some strains. The antibacterial spectrum of Paenibacillus polymyxa is wide, covering the basic component strains of the activated sludge microbial floc, including Gram-negative bacteria, Gram-positive bacteria, fungi, etc., and has strong antibacterial properties. At the same time, Paenibacillus polymyxa can secrete high-molecular organic substances and has a powerful biological flocculation function. At present, it has been used as a safe and harmless bioflocculant in the field of sewage treatment, but its role in sludge flocculation treatment and improving sludge dewatering performance has not been studied. The present invention points out that Paenibacillus polymyxa has both good cell-breaking and flocculation functions and has great potential to improve sludge sedimentation and dewatering performance. Compared with the physical and chemical treatment methods of sludge, the microbial treatment method has low requirements for equipment and operation, saves energy and reduces consumption, has low carbon emissions, is environmentally friendly, does not produce secondary pollution, has a high calorific value after sludge treatment, and is convenient for subsequent composting, incineration and other treatment and disposal.

[0006] Based on the above characteristics, the broad-spectrum antibacterial and cell-breaking ability and powerful biological flocculation ability of Paenibacillus polymyxa make it have great application potential in sludge biological pretreatment and improving sludge sedimentation and dewatering performance, can effectively reduce the cost and energy consumption of sludge treatment and disposal, and have good economic and environmental benefits. Summary of the Invention

[0007] Technical Problem:

[0008] Municipal sewage treatment plants produce a large amount of excess sludge. Deep dewatering treatment of sludge is a necessary front-end operation to reduce the moisture content and volume of sludge and achieve harmless, stable and resource-based treatment and disposal of sludge. In the moisture composition of sludge, the bound water inside sludge particles and microbial cells can only be removed by destroying the structures of sludge and microbial cells. Sludge conditioning and modification pretreatment can effectively improve the sludge dewatering performance and the efficiency of subsequent deep dewatering treatment. Currently, it mainly includes physical, chemical and biological methods. Compared with physical and chemical methods, which have the disadvantages of high energy consumption, complex equipment, high maintenance costs and secondary pollution, sludge biological pretreatment can greatly damage the rigid cell membrane structure that hinders cell lysis, effectively help release the intracellular water, bound water and interstitial water that are difficult to remove in sludge, and can effectively improve the sludge dewatering efficiency on the basis of energy conservation and consumption reduction.

[0009] Technical solution:

[0010] Aiming at the technical problems existing in current sludge pretreatment, the present invention discloses a novel biological flocculation and cell lysis pretreatment method for sludge based on Paenibacillus polymyxa. This method first proposes that Paenibacillus polymyxa, which has both antibacterial cell lysis and biological flocculation functions, can be applied to the biological cell wall breaking of sludge cells, and can significantly improve the sludge dewatering performance.

[0011] To achieve the above object, the technical solution of the present invention is as follows:

[0012] A novel biological flocculation and cell lysis pretreatment method for sludge based on Paenibacillus polymyxa, comprising the following steps:

[0013] S01: Prepare a Paenibacillus polymyxa bacterial agent with high-efficiency sludge flocculation and cell lysis effects;

[0014] S02: Put the above-mentioned Paenibacillus polymyxa bacterial agent into the sludge to be dehydrated pretreated, and carry out a biological flocculation coupled cell lysis reaction;

[0015] Among them, the Paenibacillus polymyxa is a kind of spore-forming Gram-positive bacterium with cell lysis antibacterial properties and biological flocculation functions, and can produce various antibacterial substances such as peptides, proteins, nucleosides, pyrazines and phenols. It can act on the bacterial cell membrane or fungal cell wall in the sludge zoogloea, causing cell rupture and cell death, thus helping to release the intracellular bound water. In addition, the biological flocculation active organic substances produced by Paenibacillus polymyxa can be used for sludge flocculation, thereby further improving the sludge water separation performance. The present invention first proposes to apply Paenibacillus polymyxa to the sludge dewatering treatment process, which is a novel application method of Paenibacillus polymyxa, and has the advantages of simple operation, no secondary pollution, energy conservation and consumption reduction, and good social, economic and environmental benefits.

[0016] Further, in the step S01, the preparation process of the Paenibacillus polymyxa bacterium agent includes: inoculating Paenibacillus polymyxa into a liquid medium, culturing it in a constant temperature shaker at 20-35°C and 100-200 r / min for 12-48 h to obtain a Paenibacillus polymyxa bacterial liquid; centrifuging the bacterial liquid at 4000-9000 r / min for 10-30 min, and taking the precipitate to adjust its concentration to 10 5 ~10 9 CFU / mL to obtain the Paenibacillus polymyxa bacterium agent that can effectively improve the sludge dewatering performance. The preparation process of this bacterium agent is simple, has low requirements for equipment, short required culture time, does not require additional aeration, low energy consumption, and a high viable bacteria count, up to about 1-5×10 9 CFU / mL. In addition, although the liquid bacterium agent mentioned in the present invention does not need to evaporate water or freeze-dry to form a solid bacterium agent, the Paenibacillus polymyxa solid bacterium agent also has good sludge lysis effect.

[0017] Further, the components of the liquid medium are: 1000 mL of sterile water, 7-13 g of Casitone, 3-8 g of Baker Yeast, 0.7-1.3 g of MgSO4·7H2O, adjusting the pH to 6.8-7.2, and autoclaving at high pressure for 20-30 min and then cooling to room temperature. The components of this liquid medium are all common reagents, are simple and easy to obtain, and the bacterium agent culture cost is low.

[0018] Further, the sludge in the step S02 is the sludge produced by the sewage biological treatment method used in municipal sewage treatment plants, mainly including activated sludge and excess sludge.

[0019] When using the Paenibacillus polymyxa bacterium agent for biological flocculation coupled with cell disruption sludge pretreatment, the bacterium agent is put into the sludge whose dewatering performance needs to be improved in the pretreatment, and the sludge concentration can be between 10-35 g / L. The action concentration of the bacterium agent can be adjusted by adjusting the bacterium-sludge dosing ratio. The present invention finds that the action concentration range of Paenibacillus polymyxa is wide, reaching 10 4 ~10 9 CFU / mL, showing extremely low bacterium agent culture time and reagent cost requirements. After adding the liquid bacterium agent, mix it quickly, and react at a constant temperature with shaking for 8-48 hours, and the shaking speed is 80-200 r / min to make the bacterium agent fully contact with the sludge. By measuring the sludge capillary suction time (CST), sludge specific resistance (SRF) and other indexes characterizing the sludge dewatering performance and sludge volume index (SVI) and other indexes characterizing the sludge sedimentation performance, and comparing with the blank control group without adding the bacterium agent, the influence results of Paenibacillus polymyxa on the sludge dewatering and flocculation sedimentation performance can be obtained.

[0020] Beneficial effects:

[0021] (1) The present invention first proposes to use *Paenibacillus polymyxa* as the main sludge flocculating and lysing bacterium, combining its cell lysing function with the biological flocculation function, and applying it to the field of biological pretreatment of sludge dewatering. Moreover, through experiments, its remarkable treatment effect has been confirmed. After 8 - 24 hours of treatment, the *Paenibacillus polymyxa* bacterial agent can reduce the sludge CST and SRF by more than 20%, and can significantly reduce the sludge SVI by more than 10%. The steps of the sludge biological treatment process are simple and the economic cost is low. Only simple addition of the bacterial agent and mixing and stirring are required, without additional aeration or other chemical agents for assistance, which is very energy-saving and consumption-reducing, does not produce secondary pollution and has a stable effect, and has good environmental and economic benefits.

[0022] (2) In the present invention, the antibacterial substances secreted by *Paenibacillus polymyxa* can rupture the cell walls of fungi and bacteria, contributing to the release of intracellular bound water, carbon-containing organic matter and nutrients, thereby improving the sludge dewatering efficiency and biodegradability, and reducing the sludge treatment difficulty and cost. In addition, cell rupture will significantly increase the organic matter content in the sludge filtrate, contributing to the reflux and carbon supplementation of the sludge filtrate, thus contributing to the biological treatment of sewage, saving the dosage of externally added carbon sources, and realizing the recycling of resources.

[0023] (3) The present invention has wide applicability. *Paenibacillus polymyxa* has extremely strong adaptability and can adapt to a wide range of municipal surplus sludge conditions. It is effective for sludge with a concentration of 10 - 35 g / L and can be used to improve the dewatering performance of surplus sludge generated by common sewage biological treatment processes. In addition, *Paenibacillus polymyxa* can form highly stress-resistant spores, can germinate and grow in a variety of culture media, and is easy to prepare into a solid bacterial agent, and its solid bacterial agent also has a remarkable sludge lysing effect. The required effective action concentration of this bacterial agent is low, the preparation steps are simple, the required time is short, the cultivation of the bacterial agent does not require complex compounds and processes, and the preservation and transportation costs are low, and industrial application can be realized.

[0024] (4) The present invention has biological safety. *Paenibacillus polymyxa* widely exists in nature and is a non-pathogenic bacterium whose safety is recognized, has no toxic or side effects on public health, and has been industrially applied in the prevention and control of plant diseases. The *Paenibacillus polymyxa* used in the present invention is screened from sludge and belongs to the indigenous microorganisms in the sludge, and does not cause ecological harm in the subsequent treatment and disposal of sludge. Description of the Drawings

[0025] Figure 1 It is a CST change diagram of *Paenibacillus polymyxa* treating municipal surplus sludge;

[0026] Figure 2 It is a SRF change diagram of *Paenibacillus polymyxa* treating municipal surplus sludge;

[0027] Figure 3SVI change diagram of Paenibacillus polymyxa treating municipal surplus sludge;

[0028] Figure 4 CST change diagram of Paenibacillus polymyxa treating municipal surplus sludge at different concentrations of added bacterial agents;

[0029] Figure 5 SRF change diagram of Paenibacillus polymyxa treating municipal surplus sludge at different concentrations of added bacterial agents;

[0030] Figure 6 CST change diagram of Paenibacillus polymyxa treating municipal surplus sludge at different sludge concentrations;

[0031] Figure 7 SRF change diagram of Paenibacillus polymyxa treating municipal surplus sludge at different sludge concentrations. Specific implementation manners

[0032] The present invention will be further clarified below in conjunction with the accompanying drawings and specific implementation manners. It should be understood that the following specific implementation manners are only used to illustrate the present invention and not to limit the scope of the present invention.

[0033] Paenibacillus polymyxa, as an antibacterial and flocculant-producing microorganism, is added to the surplus sludge of a municipal sewage treatment plant for mixed cultivation, used for the release and flocculation of intracellular bound water in municipal sludge, and to improve the sludge dewatering and sedimentation performance.

[0034] For the experimental methods without specific conditions in the following examples, they are carried out according to conventional methods and conditions, or selected according to the product instruction manual.

[0035] The Paenibacillus polymyxa used in this experiment are numbered as Z-11, Z-15, Z-19, and Z-29 respectively, and are all screened from the sludge in the thickening tank of a municipal sludge treatment plant in Nanjing. After 16S rRNA bacterial species identification, they are all Paenibacillus polymyxa.

[0036] Example 1: Influence of Paenibacillus polymyxa on the dewatering and sedimentation performance of surplus sludge produced by municipal sewage

[0037] The sludge treatment is carried out in batches in the laboratory using the process of the present invention. The sludge to be treated comes from the sludge thickening tank of a municipal sewage treatment plant in Nanjing, which uses the A2 / O process.

[0038] (1) Preparation of Paenibacillus polymyxa bacterial agent

[0039] Preparation of Paenibacillus polymyxa inoculant: Four strains of Paenibacillus polymyxa, namely Z-11, Z-15, Z-19 and Z-29, were inoculated into a nutrient-rich liquid medium and cultured in a constant-temperature shaker at 30 °C and 150 r / min for 12 - 24 h to complete the fermentation of the bacterial liquid. The medium used in this experiment was CYE medium, and other common nutrient-rich liquid media, such as NB medium, CAS medium, potato dextrose medium, etc., could all be used for culturing Paenibacillus polymyxa. The bacterial liquid was centrifuged at 7000 r / min and 4 °C for 20 min, and the precipitate was resuspended with sterile phosphate buffer, and the concentration of the inoculant was adjusted to 10 8 CFU / mL.

[0040] The formula of the CYE liquid medium is: 1000 mL of sterile water, 7 - 13 g of Casitone, 3 - 8 g of Baker Yeast, 0.7 - 1.3 g of MgSO4·7H2O, adjust the pH to 6.8 - 7.2, autoclave at high pressure for 20 - 30 min and then cool to room temperature.

[0041] (2) Pretreatment of excess sludge experiment

[0042] After the sludge was naturally settled, the supernatant was discarded, the concentration of sludge mixed liquor suspended solids (MLSS) was adjusted to 20 - 25 g / L, the pH was measured to be 6.95, and the water content was about 98%. The sludge was stirred evenly and then divided into 10 1-L wide-mouth conical flasks, with 400 mL of sludge in each flask.

[0043] (3) Process of Paenibacillus polymyxa sludge biological treatment experiment

[0044] 4 mL of the inoculant prepared from Z-11, Z-15, Z-19 and Z-29 were respectively added to 4 of the above-mentioned wide-mouth conical flasks containing 400 mL of sludge, and quickly stirred and mixed evenly. One set of parallel experiments was set for each inoculant. Another 2 flasks of sludge with the same volume were respectively added with 4 mL of sterile phosphate buffer, and quickly stirred and mixed evenly as the blank control group, denoted as the "KB" group.

[0045] The above conical flasks were placed in a constant-temperature shaking incubator and cultured on a shaker at 150 r / min at 30 °C for 8 - 24 hours. Samples were taken every 4 h to measure the capillary suction time (CST) of the sludge, and samples were taken every 12 h to measure the specific resistance to filtration (SRF) and sludge volume index (SVI) of the sludge.

[0046] (4) Results of Paenibacillus polymyxa sludge biological treatment experiment

[0047] The results of this experiment are respectively as Figures 1 to 3As shown, sludge CST, SRF, and SVI are respectively used to determine the dewatering and sedimentation performance of sludge. The experimental results show that after treatment with four strains of Paenibacillus polymyxa, the sludge CST, SRF, and SVI are all significantly reduced. At 16 hours, Z-19 can significantly reduce the sludge CST by 21.9%, which is the maximum CST reduction rate in this experiment. Z-11, Z-15, and Z-29 can respectively significantly reduce the CST by 16.0%, 16.6%, and 20.7% during the 24-hour reaction cycle ( Figure 1 ). In addition, Z-11, Z-15, Z-19, and Z-29 can respectively reduce the sludge SRF by up to 8.8%, 14.5%, 21.1%, and 18.9% ( Figure 2 ). Paenibacillus polymyxa significantly reduces the sludge SVI by 12 - 17% in this experiment ( Figure 3 ), showing a good effect of improving the sludge sedimentation performance. This experiment proves that Paenibacillus polymyxa has the ability to improve the dewatering and sedimentation performance of sludge and can effectively promote the separation of sludge and water.

[0048] Example 2: Effect of Paenibacillus polymyxa on the Dewatering and Sedimentation Performance of Sludge under Different Concentrations of Bacterial Agent Added

[0049] The batch treatment of sludge was carried out in the laboratory using the process of the present invention, and the sludge source was the same as that in Example 1.

[0050] (1) Preparation of Paenibacillus polymyxa Bacterial Agent

[0051] Combined with the experimental results in Example 1, Z-19, which had the best effect on improving the dewatering and sedimentation performance of municipal surplus sludge in this experiment, was selected to prepare the Paenibacillus polymyxa bacterial agent. The preparation method was the same as that in Example 1, except that when the bacterial liquid was centrifuged and resuspended with sterile phosphate buffer, the concentrations of the bacterial liquid were adjusted to 10 9 CFU / mL, 10 8 CFU / mL, 10 7 CFU / mL, 10 6 CFU / mL, and 10 5 CFU / mL respectively.

[0052] (2) Pretreatment of Surplus Sludge Experiment

[0053] The process of sludge experiment pretreatment was the same as that in Example 1, except that the number of sludge aliquots increased to 12 bottles.

[0054] (3) Process of Paenibacillus polymyxa Sludge Biological Treatment Experiment

[0055] 4 mL of each of the above-mentioned Z-19 bacterial agents with different concentrations were respectively added to the above-mentioned wide-mouth conical flasks containing 400 mL of sludge, and quickly stirred and mixed evenly. One set of parallel samples was set for each bacterial agent concentration. The concentration of the added bacterial agent was 109 CFU / mL, 10 8 CFU / mL, 10 7 CFU / mL, 10 6 CFU / mL and 10 5 CFU / mL groups, denoted as "9 times", "8 times", "7 times", "6 times" and "5 times" groups respectively. Another 2 bottles of sludge with equal volume were taken, 4 mL of sterile phosphate buffer was added to each, and they were quickly stirred and mixed evenly to serve as the blank control group, denoted as the "KB" group.

[0056] The above conical flasks were placed in a constant temperature shaking incubator and cultured on a shaker at 150 r / min at 30 °C for 8 - 24 hours. Samples were taken every 4 h to measure the capillary suction time (CST) of the sludge, and samples were taken every 12 h to measure the specific resistance to filtration (SRF) of the sludge.

[0057] (5) Experimental results

[0058] The results of this experiment are as Figures 4 to 5 shown. The experimental results prove that the Paenibacillus polymyxa Z-19 bactericide within the concentration range of 10 9～ 10 5 CFU / mL all has the effect of reducing the CST and SRF of the sludge, showing a good effect of improving the sludge dewatering performance. When the concentration of the added bactericide is 10 9 CFU / mL, 10 8 CFU / mL, 10 7 CFU / mL, 10 6 CFU / mL and 10 5 CFU / mL, the maximum reduction rates of the sludge CST can reach 12.8%, 19.7%, 11.8%, 23.2% and 19.7% respectively, and the maximum reduction rates of the SRF can reach 12.5%, 18.1%, 16.0%, 18.5% and 20.4% respectively. The decrease in the bactericide concentration does not affect the cell lysis efficiency of Paenibacillus polymyxa Z-19, and promotes the release of intracellular bound water in the sludge and the improvement of dewatering performance. A lower bactericide concentration will significantly reduce the resources and energy consumption required for bactericide cultivation and fermentation when Paenibacillus polymyxa is applied to sludge biological pretreatment, having an economic cost advantage of reducing costs and increasing efficiency.

[0059] Example 3: Effect of Paenibacillus polymyxa on Sludge Dewatering and Settling Performance under Different Sludge Concentrations

[0060] The sludge was batch-treated in the laboratory using the process of the present invention, and the sludge source was the same as that in Example 1.

[0061] (1) Preparation of Paenibacillus polymyxa Bactericide

[0062] Based on the experimental results in Example 1, select the Paenibacillus polymyxa Z-19 that shows the best improvement effect on the dewatering and sedimentation performance of municipal surplus sludge in this experiment to prepare the Paenibacillus polymyxa bacterium agent. The preparation method is the same as that in Example 1.

[0063] (2) Pretreatment of the surplus sludge experiment

[0064] Adjust the MLSS of the sludge taken from the sludge thickening tank to 15 g / L, 20 g / L, 25 g / L, 30 g / L, and 35 g / L respectively using the sludge supernatant. Then, separately fill 400 mL of each concentration into 1-L wide-mouth conical flasks, with 4 flasks filled for each sludge concentration. Among them, 2 flasks are used as the experimental groups for adding the Paenibacillus polymyxa Z-19 bacterium agent, and the other 2 flasks are used as the blank control groups for adding the same volume of sterile phosphate buffer solution.

[0065] (3) Process of the Paenibacillus polymyxa sludge biological treatment experiment

[0066] Add 2 mL of the Z-19 bacterium agent to the 2 experimental group sludge samples at each sludge concentration, and add 2 mL of sterile phosphate buffer solution to the corresponding 2 blank control group sludge samples at the same concentration. Then, quickly stir and mix evenly.

[0067] Place the above conical flasks in a constant temperature shaking incubator and culture them on a shaker at 150 r / min at 30 °C for 8 - 24 hours. Take samples every 4 h to measure the capillary suction time (CST) of the sludge, and take samples every 12 h to measure the specific resistance to filtration (SRF) of the sludge.

[0068] (4) Experimental results

[0069] Paenibacillus polymyxa has a good effect on improving the dewatering performance of municipal surplus sludge at various sludge concentrations ( Figures 6 to 7 ). At sludge concentrations of 15 g / L, 20 g / L, 25 g / L, 30 g / L, and 35 g / L, Paenibacillus polymyxa Z-19 can significantly reduce the CST of the sludge by 15.4%, 16.6%, 20.0%, 20.2%, and 18.5% respectively, and significantly reduce the SRF of the sludge by 7.4%, 17.5%, 20.9%, 20.5%, and 15.9% respectively. The sludge concentration affects the reduction rates of CST and SRF by Paenibacillus polymyxa Z-19, and it has a better effect on improving the dewatering performance of sludge with a concentration of 20 - 30 g / L. However, it still has a good treatment effect on municipal surplus sludge under other sludge concentration conditions, has a wide adaptation range, and can act on sludge concentrations that basically cover the existing concentration range of municipal surplus sludge, showing general adaptability.

[0070] It should be noted that the above content only illustrates the technical idea of the present invention, and the protection scope of the present invention cannot be limited thereby. For those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements all fall within the protection scope of the claims of the present invention.

Claims

1. A novel sludge bioflocculation and cell disruption pretreatment method based on Paenibacillus polymyxa, characterized in that, Including the following steps: S01: Prepare a Paenibacillus polymyxa bacterial agent with efficient sludge flocculation and cell lysis effects; S02: Put the above-mentioned Paenibacillus polymyxa bacterial agent into the sludge to be dehydrated pretreated, and carry out biological flocculation coupled with cell lysis reaction; Among them, the Paenibacillus polymyxa is a spore-producing Gram-positive bacterium.

2. A novel sludge bioflocculation and cell lysis pretreatment method based on Paenibacillus polymyxa according to claim 1, characterized in that, In the step S01, the preparation process of the Paenibacillus polymyxa bacterial agent includes: inoculating Paenibacillus polymyxa into a liquid medium, culturing it in a constant temperature shaker at 20-35°C and 100-200 r / min for 12-48 h to obtain a Paenibacillus polymyxa bacterial solution; centrifuging the bacterial solution at 4000-9000 r / min for 10-30 min, taking the precipitate and adjusting the concentration of the bacterial solution to 10 5 ~10 9 CFU / mL to obtain a Paenibacillus polymyxa bacterial agent that can effectively improve the sludge dewatering performance.

3. A novel sludge bioflocculation and cell lysis pretreatment method based on Paenibacillus polymyxa according to claim 2, characterized in that, The formula of the liquid medium is: 1000 mL of sterile water, 7 - 13 g of Casitone, 3 - 8 g of Baker Yeast, 0.7 - 1.3 g of MgSO4·7H2O, adjust the pH to 6.8 - 7.2, autoclave for 20 - 30 min and then cool to room temperature.

4. A novel sludge bioflocculation and cell disruption pretreatment method based on Paenibacillus polymyxa according to claim 1, characterized in that, The sludge in step S02 is the sludge produced by the sewage biological treatment method used in municipal sewage treatment plants, mainly including activated sludge and excess sludge.

5. A novel sludge bioflocculation and cell disruption pretreatment method based on Paenibacillus polymyxa according to claim 1, characterized in that, In the step S02, the final action concentration of Paenibacillus polymyxa in the sludge is 10 4 ~10 9 CFU / mL, the applicable sludge concentration is 10-35 g / L. After adding the bacterial agent, stir quickly and mix evenly, and then culture under constant temperature and shaking.

6. A novel sludge bioflocculation and cell lysis pretreatment method based on Paenibacillus polymyxa according to claim 1, characterized in that, The biological flocculation and cell lysis reaction time in step S02 is 8 - 48 hours, and the rotation speed during shaking culture is 80 - 200 r / min.

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