Purification treatment process for livestock breeding sewage

Abstract

The invention discloses a purification treatment process for livestock breeding sewage, and belongs to the technical field of functional microbial materials and application. According to the invention, by introducing the composite functional microbial agent and the mushroom bran-based biomass composite filler, efficient removal of ammonia nitrogen, COD and other pollutants in sewage is realized, and the risk of secondary pollution caused by a traditional chemical treatment method is greatly reduced. Pseudomonas filbertii, microbacterium keratinolyticum and bacillus licheniformis in the composite functional microbial agent have a synergistic effect, so that organic matters and ammonia nitrogen in sewage can be rapidly degraded, and the composite functional microbial agent also has a good flocculation effect, has good environmental adaptability and stability, and can cope with complex and variable water quality conditions. In addition, the mushroom bran-based biomass composite filler is subjected to acid pickling activation and iron-chitosan loading modification, so that the adsorption performance and nitrogen and phosphorus removal capacity of the mushroom bran-based biomass composite filler are remarkably improved, and the deep treatment effect is further optimized. The process is simple and convenient to operate, low in operation cost and suitable for sewage treatment requirements of large-scale farms.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of functional microbial materials and application technology, and particularly relates to a purification treatment process for livestock breeding wastewater. BACKGROUND

[0002] In recent years, the large-scale and intensive breeding technology of livestock and poultry has developed rapidly, and the discharge of breeding wastewater has been increasing. Effective treatment of breeding wastewater is an urgent problem in agricultural production. Breeding wastewater is complex in composition, containing various suspended particles, organic pollutants, and deep color, which is difficult to treat. If the livestock and poultry breeding wastewater is discharged into the surrounding environment without any treatment, it will cause serious pollution to the environment, especially to the water body and soil ecosystem. At present, there are various methods for treating livestock and poultry wastewater. They can be roughly divided into physical repair, chemical repair and biological repair.

[0003] Physical method treatment is the pretreatment of livestock and poultry wastewater before entering the biochemical treatment process, which aims to better remove the larger solid suspended matter in the wastewater, prevent the normal operation of the equipment in the later stage and reduce the equipment load. Through physical processes such as flocculation, absorption and sedimentation, insoluble pollutants in wastewater can be removed. Physical method treatment is simple and efficient, but it cannot completely remove organic matter and nitrogen and phosphorus pollutants in wastewater, and the water quality after treatment is still difficult to meet the discharge standard.

[0004] Chemical method refers to changing the chemical structure of some pollutants in wastewater in the form of solubility or colloidal state through some chemical methods, so as to achieve harmless or conversion into easy-to-treat substances. Chemical method has good treatment effect, but its treatment cost is high. It has uncontrollability, and other compounds can be easily produced due to environmental changes, resulting in secondary pollution.

[0005] Bioremediation refers to the use of plants, certain specific organisms such as microorganisms or protozoa to absorb, transform, remove or degrade pollutants in the surrounding environment, so as to restore the polluted environment and achieve the purpose of completely removing pollutants and restoring ecological effects. It is an effective means composed of an ecological system to improve environmental quality. Due to the high concentration of ammonia nitrogen and COD in livestock and poultry breeding wastewater, it is generally difficult to remove them by physical and chemical methods. Biological repair can quickly reduce ammonia nitrogen and COD. Compared with traditional physical and chemical repair, biological repair is generally considered as a sustainable technology, which has the advantages of economic efficiency, low energy consumption and no secondary pollution.

[0006] For example: Chinese patent application CN202211390528.5 discloses a preparation method of a microbial agent for treating dairy farming wastewater and an organic fertilizer. The microbial agent for treating dairy farming wastewater is prepared from the following components in the specified mass fractions: solid fermentation agent 12-18 parts, liquid fermentation agent 10-20 parts, and ammonia nitrogen removal agent 10-20 parts.

[0007] However, the existing bioremediation technology still faces many challenges in practical application. For example, the adaptability and stability of microbial agents are poor, and they are greatly affected by environmental temperature, pH value, dissolved oxygen and other factors, making it difficult to maintain high degradation capacity in complex and variable wastewater environment. In addition, the bioremediation period is long, and the response to sudden and high-concentration pollutant impact load is weak. It still needs to rely on subsequent complex chemical flocculation and advanced oxidation processes, which has high operation cost and secondary pollution risk. Therefore, how to improve the adaptability and remediation efficiency of bioremediation technology has become the focus of current research. We believe that on the one hand, we can screen and cultivate functional microorganisms with strong tolerance and high degradation efficiency to enhance their activity and stability in complex environment. On the other hand, physical and chemical methods are combined for synergistic treatment to optimize the overall remediation effect. Therefore, the present invention strives to solve the problems existing in the prior art from these angles. SUMMARY

[0008] The present invention selects a bacillus licheniformis with high ammonia nitrogen degradation capacity and biological flocculation effect, and combines it with pseudomonas pinipeti and microbacterium corchori to form a functional microbial group, which can realize the simultaneous and efficient removal of ammonia nitrogen and COD in livestock breeding wastewater, purify the water quality, and significantly reduce the dependence on subsequent chemical treatment, thereby reducing the risk of secondary pollution. The functional microbial group has good environmental adaptability and stability, and is particularly suitable for livestock breeding wastewater treatment under complex water quality conditions.

[0009] To achieve the above technical purpose, the technical solution adopted by the present invention is: A purification treatment process for livestock breeding wastewater, comprising the following preparation steps: (1) Pretreatment: the livestock breeding wastewater to be treated is removed of large suspended solids and impurities by a grating machine, and then enters a sand settling tank for preliminary sedimentation to separate heavy particles such as sand and gravel, thereby reducing the subsequent treatment load; (2) Primary treatment: the pretreated wastewater is introduced into a hydrolysis acidification tank, with a hydraulic retention time of 6-8 hours, and the original facultative microorganisms in the tank are used for preliminary fermentation and decomposition; (3) Core microbial treatment: The effluent from the hydrolysis acidification tank is introduced into the aerobic reaction tank, the pH is adjusted to 6.5-7.5, 1-3% of the wastewater quality is added to the composite functional bacteria agent, intermittent aeration is adopted, aeration is carried out for 15 minutes, and reaction is carried out for 45 minutes, the hydraulic retention time is 12-18 hours; (4) Solid-liquid separation: The effluent from the aerobic reaction tank is introduced into the sedimentation tank, and is statically settled for 1-2 hours, and the mud-water separation is realized by relying on the biological flocculation of microorganisms themselves; (5) Advanced treatment and disinfection: The supernatant from the sedimentation tank is introduced into the filter tank filled with straw-based biomass composite filler for the final denitrification and phosphorus removal purification, the hydraulic retention time is controlled to be 1-2 hours, and finally ultraviolet or ozone is used for disinfection treatment before discharge. When using ultraviolet disinfection, the effective ultraviolet dose should be ≥30 mJ / cm² (millijoule / square centimeter). If ozone is used, the ozone dosage is controlled to be 5-10 mg / L.

[0010] Further, the composite functional bacteria agent in step (3) comprises Pseudomonas fluorescens, Microbacterium coriellii and Bacillus licheniformis, and the volume ratio of the three is 1:1:1.

[0011] Further, the strain number of the Pseudomonas fluorescens is CGMCC No. 1.3819, the original preservation time is March 17, 2005; the strain number of the Microbacterium coriellii is CGMCC No. 1.6312, the original preservation time is May 12, 2006; the Pseudomonas fluorescens and the Microbacterium coriellii are purchased from the China General Microbiological Culture Collection Center, and are commercially available without biological preservation. The preservation number of the Bacillus licheniformis is CGMCC No. 79241, the classification and naming is Bacillus licheniformis, and the preservation is in the China General Microbiological Culture Collection Center, located at No. 1, Yihuang West Road, Beijing Chaoyang District, and the preservation date is March 5, 2025.

[0012] Further, the preparation method of the composite functional bacteria agent is as follows: the Pseudomonas fluorescens, the Microbacterium coriellii and the Bacillus licheniformis are inoculated into LB culture medium respectively, and are shaken and cultured until the bacterial content is O.D 600 ≈3.0, then mixed to obtain a mixed bacteria liquid according to a volume ratio of 1:1:1, the mixed bacteria liquid is mixed and adsorbed with a carrier according to a volume-mass ratio of 1L:1.5kg, the carrier is composed of attapulgite, starch and calcium chloride according to a mass ratio of 100:5:2; the adsorbed material is granulated and vacuum dried until the water content is ≤8%, thereby obtaining the composite functional bacteria agent, and the effective viable bacterial count in the composite functional microorganism is not less than 1×10 9 CFU / g.

[0013] Further, the preparation method of the step (5) fungus bran-based biomass composite filler is: (1) Raw material pretreatment: the fresh fungus bran taken from the factory of Pholiota nameko or Pleurotus eryngii is crushed and sieved, 40-60 mesh particles are taken, repeatedly washed with water until the water is clear, soluble impurities are removed, dried at 80 DEG C until the constant weight, and the pretreated fungus bran is obtained; (2) Acid washing activation: the pretreated fungus bran is placed in a 5% citric acid solution, and oscillated at 60 DEG C and 150 r / min for 2 hours; after the reaction, it is filtered, washed with deionized water until neutral, and dried; this step is used to dissolve and remove part of the inorganic salt and ash in the fungus bran, and expose more pore structure; (3) Iron-chitosan loading modification: 1.0 mol / L FeCl3 solution and chitosan acetic acid solution are prepared; the fungus bran after acid washing is immersed in the FeCl3 solution with a solid-liquid ratio of 1g:15mL, and the chitosan solution is slowly added to the system until the mass ratio of chitosan to fungus bran is 1:20, and slowly stirred at 45 DEG C for 4 hours; after the reaction, the solid is filtered, washed with deionized water for 2-3 times, vacuum dried at 60 DEG C, and cooled to obtain the fungus bran-based biomass composite filler.

[0014] Further, the solid-liquid ratio of the step (2) citric acid solution and pretreated fungus bran is 1g:10mL, and in the step (3) chitosan acetic acid solution, the solid-liquid ratio of chitosan and acetic acid solution is 1g:100mL, and the mass concentration of the acetic acid solution is 3%.

[0015] Further, the fungus bran-based biomass composite filler in the step (5) is added in an amount of 10-20g per liter of sewage.

[0016] Beneficial effects: The purification treatment process of the livestock breeding sewage provided by the application has significant technical advantages and application value. By introducing the composite functional bacterial agent and the fungus bran-based biomass composite filler, the ammonia nitrogen, COD and other pollutants in the sewage are efficiently removed, and the secondary pollution risk caused by the traditional chemical treatment method is greatly reduced. The synergistic effect of Pseudomonas piniprestalis, Microbacterium corchorusii and Bacillus licheniformis in the composite functional bacterial agent not only can quickly degrade the organic matter in the sewage, but also has good flocculation effect on ammonia nitrogen, has good environmental adaptability and stability, and can cope with complex and variable water quality conditions. In addition, the fungus bran-based biomass composite filler is activated by acid washing and modified by iron-chitosan loading, which significantly improves the adsorption performance and denitrification and phosphorus removal capacity, and further optimizes the deep treatment effect.

[0017] The process shows the characteristics of simple operation and low running cost in practical application, and is especially suitable for the sewage treatment demand of large-scale breeding farm. Compared with the prior art, the process can realize the standard discharge of sewage without relying on complex chemical flocculation or advanced oxidation process, thereby effectively relieving the pressure caused by livestock breeding wastewater on the environment. In addition, through fine control of the pretreatment, core microbial treatment and advanced treatment and other links, the stability and reliability of the whole process are ensured, which provides important technical support for the sustainable development of the livestock breeding industry. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 The bacillus licheniformis colony morphology (a) and staining characteristics (b) of the application are shown in the figure. Figure 2 The antagonistic effect between strains is shown in the figure, wherein 1 is pseudomonas pini, 2 is microbacterium luteolum, and 3 is bacillus licheniformis. Figure 3 The flocculation effect experimental results of the microbial liquid prepared from the strains of example 1 and comparative examples 1-9 of the application are shown in the figure. DETAILED DESCRIPTION

[0019] The technical solutions of the application will be further described below in combination with specific examples, but are not limited thereto.

[0020] Example 1 A purification treatment process for livestock breeding wastewater, comprising the following preparation steps: (1) Pretreatment: removing large suspended solids and impurities in the livestock breeding wastewater to be treated by a grating machine, and then introducing the wastewater into a sand settling tank for preliminary sedimentation to separate heavy particles such as sand and gravel and reduce the subsequent treatment load; (2) Primary treatment: introducing the pretreated wastewater into a hydrolysis acidification tank, with a hydraulic retention time of 6 hours, and using the original facultative microorganisms in the tank for preliminary fermentation decomposition; (3) Core microbial treatment: introducing the effluent from the hydrolysis acidification tank into an aerobic reaction tank, adjusting the pH to 6.5-7.5, adding a composite functional bacterial agent at 1% of the wastewater quality, using intermittent aeration, aeration for 15 minutes, stopping for 45 minutes for reaction, and the hydraulic retention time is 12 hours; (4) Solid-liquid separation: introducing the effluent from the aerobic reaction tank into a sedimentation tank, standing for 1 hour for sedimentation, and realizing mud-water separation by the biological flocculation of microorganisms themselves; (5) Advanced treatment and disinfection: introducing the supernatant from the sedimentation tank into a filter tank filled with straw-based biomass composite filler for the final denitrification and phosphorus removal purification, controlling the hydraulic retention time at 1 hour, and finally using ozone for disinfection treatment before discharge. The ozone dosage is controlled at 10 mg / L.

[0021] The complex functional microbial agent in step (3) comprises Pseudomonas fluorescens, Microbacterium corrhizophilum and Bacillus licheniformis, and the volume ratio of the three is 1:1:1.

[0022] The strain number of the Pseudomonas fluorescens is CGMCC No. 1.3819, and the original preservation time is March 17, 2005. The strain number of the Microbacterium corrhizophilum is CGMCC No. 1.6312, and the original preservation time is May 12, 2006. The preservation number of the Bacillus licheniformis is CGMCC No. 79241, which is preserved in the China General Microbiological Culture Collection Center, and the classification and naming of the Bacillus licheniformis is Bacillus licheniformis, the address is No. 3, Beichen West Road, Chaoyang District, Beijing, and the preservation date is March 5, 2025.

[0023] The Pseudomonas fluorescens and the Microbacterium corrhizophilum are purchased from the China General Microbiological Culture Collection Center, and can be purchased through a commercial channel without preservation.

[0024] The Bacillus licheniformis is isolated from the sludge at the bottom of a sludge pool of a waterworks in Linyi, Shandong Province, and the isolation method is as follows: 2 g of a sample is respectively connected to sterile water, and is subjected to shaking culture at 30 ℃ and 180 rpm for 3 h, and is then left to stand. 5 mL of a bacterial suspension is transferred into 100 mL of an enrichment culture medium, and is subjected to culture under the same conditions for 48 h to obtain an enriched bacterial liquid. A series of dilutions (10 -1 , 10 -2 , 10 -3 , 10 -4 , 10 -5 , 10 -6 ) of the culture liquid are prepared, 100 μL of each dilution is coated on an inverted separation culture medium, and is subjected to constant temperature culture at 30 ℃ for 48 h. The growth of the bacterial bodies is observed and recorded every day. Strains with different colony morphologies are picked and subjected to streak isolation. After multiple streak isolation, pure strains are obtained.

[0025] The enrichment culture medium comprises beef extract 3 g / L, protein peptone 10 g / L, NaCl 30 g / L, pH 7.0-7.2, and is sterilized at 121 ℃ for 30 min.

[0026] The strains screened and purified are connected to the enrichment culture medium for activation for 1 d, and then 5 mL of each is connected to 100 mL of a separation culture medium, and is subjected to shaking culture at 30 ℃ and 180 rpm for 48 h. NH4 +The concentration of N is calculated to calculate the total denitrification rate and ammonia nitrogen degradation rate. Each strain is set up in three groups. According to the total denitrification rate and ammonia nitrogen degradation rate, the strain with the best denitrification effect and the fastest growth rate is selected as the target strain.

[0027] The target strain Bacillus licheniformis is cultured on LB solid medium at 30 DEG C for 36 hours, and the colony is milky white, raised, smooth, round, and transparent. Figure 1 (a), and gram staining is negative as shown in (b).

[0028] Strain antagonism experiment: after activation of Pseudomonas pinipestis, Microbacterium luteolum and Bacillus licheniformis, they are adjusted to the same concentration, and the inoculation ring is used to dip the bacterial liquid on the same nutrient agar solid medium plate to draw a line, and the antagonism phenomenon is observed after 48 hours of culture at 30 DEG C. The results show that Bacillus licheniformis and Pseudomonas pinipestis, Microbacterium luteolum do not appear obvious inhibition zone on the culture medium, indicating that there is no antagonism between the three, which can be used in combination (as shown in Figure 2 ).

[0029] The preparation method of the composite functional bacteria agent is as follows: Pseudomonas pinipestis, Microbacterium luteolum and Bacillus licheniformis are inoculated into LB medium respectively, and oscillation culture is carried out until the bacterial content is O.D 600 ≈3.0, then mixed to obtain a mixed bacterial liquid according to the volume ratio of 1:1:1, and the mixed bacterial liquid is mixed and adsorbed with a carrier according to the volume-mass ratio of 1L:1.5kg, the carrier is composed of attapulgite, starch and calcium chloride according to the mass ratio of 100:5:2; the adsorbed material is granulated and vacuum dried to a water content of ≤8%, to obtain the composite functional bacteria agent, and the effective viable bacteria number in the composite functional microorganism is not less than 1x10 9 CFU / g.

[0030] The preparation method of the straw-based biomass composite filler is as follows: (1) Raw material pretreatment: the fresh straw taken from the Pleurotus eryngii or Pleurotus eryngii factory is crushed and sieved, and the 40-60 mesh particles are repeatedly washed with water until the water is clear, and the soluble impurities are removed, and the pretreated straw is dried at 80 DEG C until the weight is constant; (2) Acid washing activation: the pretreated straw is placed in a 5% citric acid solution, and oscillated at 60 DEG C and 150 r / min for 2 hours; after the reaction is completed, the straw is filtered and washed with deionized water until it is neutral, and then dried; this step is used to dissolve and remove part of the inorganic salts and ash in the straw, and expose more pore structures; (3) Iron-chitosan loading modification: prepare a 1.0 mol / L FeCl3 solution and a chitosan acetic acid solution; immerse the acid-washed straw in the FeCl3 solution at a solid-liquid ratio of 1 g: 15 mL, slowly add the chitosan solution to the system, the mass ratio of chitosan to straw is 1:20, slowly stir at 45°C for 4 hours; after the reaction is completed, filter, wash the obtained solid with deionized water 2-3 times, vacuum dry at 60°C, and after cooling, the straw-based biomass composite filler is obtained.

[0031] In step (2), the solid-liquid ratio of the citric acid solution to the pretreated straw is 1 g: 10 mL, and in step (3), the solid-liquid ratio of chitosan to acetic acid solution in the chitosan acetic acid solution is 1 g: 100 mL, and the mass concentration of the acetic acid solution is 3%.

[0032] In step (5), the addition amount of the straw-based biomass composite filler is 10 g per liter of sewage.

[0033] Example 2 A purification treatment process for livestock breeding wastewater, comprising the following preparation steps: (1) Pretreatment: the livestock breeding wastewater to be treated is subjected to removal of large suspended solids and impurities by a grating machine, and then subjected to preliminary sedimentation in a sand settling tank to separate heavy particles such as sand and gravel and reduce the subsequent treatment load; (2) Primary treatment: the pretreated wastewater is introduced into a hydrolysis acidification tank, the hydraulic retention time is 7 hours, and the original facultative microorganisms in the tank are used for preliminary fermentation decomposition; (3) Core microbial treatment: the effluent from the hydrolysis acidification tank is introduced into an aerobic reaction tank, the pH is adjusted to 6.5-7.5, the composite functional bacterial agent is added at 2% of the mass of the wastewater, the intermittent aeration mode is adopted, the aeration time is 15 minutes, and the reaction is stopped for 45 minutes, the hydraulic retention time is 15 hours; (4) Solid-liquid separation: the effluent from the aerobic reaction tank is introduced into a sedimentation tank, and is allowed to stand for 1 hour for sedimentation, and the mud-water separation is realized by the biological flocculation of the microorganisms themselves; (5) Advanced treatment and disinfection: the supernatant from the sedimentation tank is introduced into a filter tank filled with straw-based biomass composite filler for the final denitrification and phosphorus removal purification, the hydraulic retention time is controlled at 1.5 hours, and finally ultraviolet disinfection is used for treatment and discharge. The effective ultraviolet dose for ultraviolet disinfection is 40 mJ / cm² (millijoule / square centimeter).

[0034] The composite functional bacterial agent in step (3) comprises Pseudomonas pinophilum, Microbacterium corchenelli, and Bacillus licheniformis, and the volume ratio of the three is 1:1:1.

[0035] The strain number of the Pseudomonas rhizoxinifaciens is CGMCC No. 1.3819, the strain number of the Lysinibacillus xylanilyticus is CGMCC No. 1.6312, and the preservation number of the Bacillus licheniformis is CGMCC No. 79241, which is preserved in the China General Microbiological Culture Collection Center, located at No. 1, Yihuangyuan, Beichenxi Road, Beijing.

[0036] The isolation and screening method of the Bacillus licheniformis is the same as that in Embodiment 1.

[0037] The preparation method of the complex functional microbial agent is the same as that in Embodiment 1.

[0038] The preparation method of the fungus-straw-based biomass composite filler in step (5) is as follows: (1) Raw material pretreatment: Fresh fungus-straw taken from a Pholiota nameko or Pleurotus eryngii factory is crushed and sieved, and 40-60 mesh particles are taken, washed repeatedly with water until the effluent is clear, and soluble impurities are removed. The pretreated fungus-straw is dried at 80°C until the weight is constant to obtain the pretreated fungus-straw. (2) Acid washing and activation: The pretreated fungus-straw is placed in a 5% citric acid solution, and oscillated at 60°C and 150 r / min for 2 hours. After the reaction, the fungus-straw is filtered, washed with deionized water until neutral, and dried. This step is used to dissolve and remove part of the inorganic salts and ash in the fungus-straw, and expose more pore structures. (3) Iron-chitosan loading modification: A 1.0 mol / L FeCl3 solution and a chitosan acetic acid solution are prepared. The acid-washed fungus-straw is immersed in the FeCl3 solution at a solid-liquid ratio of 1g:15mL, and the chitosan solution is slowly added to the system until the mass ratio of chitosan to fungus-straw is 1:20. The system is slowly stirred at 45°C for 4 hours. After the reaction, the fungus-straw is filtered, washed with deionized water for 2-3 times, and dried at 60°C under vacuum. The fungus-straw-based biomass composite filler is obtained after cooling.

[0039] In step (2), the solid-liquid ratio of the citric acid solution to the pretreated fungus-straw is 1g:10mL. In step (3), the solid-liquid ratio of chitosan to acetic acid solution in the chitosan acetic acid solution is 1g:100mL, and the mass concentration of the acetic acid solution is 3%.

[0040] In step (5), the addition amount of the fungus-straw-based biomass composite filler is 15g per liter of wastewater.

[0041] Embodiment 3 A purification treatment process for livestock breeding wastewater includes the following preparation steps: (1) Pretreatment: The livestock breeding wastewater to be treated is subjected to a grating machine to remove large suspended solids and impurities, and then enters a sand trap for preliminary sedimentation to separate heavy particles such as sand and gravel, thereby reducing the load of subsequent treatment. (2) Primary treatment: the pretreated wastewater is introduced into a hydrolysis acidification tank, the hydraulic retention time is 8 hours, and the original facultative microorganisms in the tank are used for preliminary fermentation decomposition; (3) Core microbial treatment: the effluent from the hydrolysis acidification tank is introduced into an aerobic reaction tank, the pH is adjusted to 6.5-7.5, 3% of the wastewater quality is added with a composite functional bacterial agent, intermittent aeration is adopted, aeration is performed for 15 minutes, and reaction is performed for 45 minutes, the hydraulic retention time is 18 hours; (4) Solid-liquid separation: the effluent from the aerobic reaction tank is introduced into a sedimentation tank, and is allowed to stand for 2 hours for sedimentation, and mud-water separation is realized by relying on the biological flocculation of the microorganisms themselves; (5) Advanced treatment and disinfection: the supernatant from the sedimentation tank is introduced into a filter tank provided with straw-based biomass composite filler for the last denitrification and phosphorus removal purification, the hydraulic retention time is controlled to be 2 hours, and finally ultraviolet disinfection treatment is performed before discharge. The effective ultraviolet dose is 40 mJ / cm² (millijoule / square centimeter) in the ultraviolet disinfection.

[0042] The composite functional bacterial agent in step (3) comprises Pseudomonas monteilii, Microbacterium corchorusii and Bacillus licheniformis, and the volume ratio of the three is 1:1:1.

[0043] The strain number of the Pseudomonas monteilii is CGMCC No. 1.3819, the strain number of the Microbacterium corchorusii is CGMCC No. 1.6312, and the preservation number of the Bacillus licheniformis is CGMCC No. 79241, which is preserved in the China General Microbiological Culture Collection Center, No. 1, Beichen West Road, Haidian District, Beijing.

[0044] The separation and screening method of the Bacillus licheniformis is the same as that in Example 1.

[0045] The preparation method of the composite functional bacterial agent is the same as that in Example 1.

[0046] The preparation method of the straw-based biomass composite filler in step (5) is as follows: (1) Raw material pretreatment: fresh straw waste from a golden needle mushroom or a Pleurotus eryngii factory is crushed and sieved, 40-60 mesh particles are taken, and are repeatedly washed with water until the effluent is clear, soluble impurities are removed, and the pretreated straw waste is dried at 80°C until the weight is constant; (2) Acid pickling activation: the pretreated straw waste is placed in a 5% citric acid solution, and is oscillated at 60°C and 150 r / min for 2 hours; after the reaction is completed, the straw waste is filtered, washed with deionized water until neutral, and dried; this step is used for dissolving and removing part of the inorganic salts and ash in the straw waste, and exposing more pore structures; (3) Iron-chitosan loading modification: prepare a 1.0 mol / L FeCl3 solution and a chitosan acetic acid solution; immerse the acid-washed straw in the FeCl3 solution at a solid-liquid ratio of 1 g: 15 mL, slowly add the chitosan solution to the system, and the mass ratio of chitosan to straw is 1:20, slowly stir at 45°C for 4 hours; after the reaction is completed, filter, wash the obtained solid with deionized water 2-3 times, vacuum dry at 60°C, and cool to obtain the straw-based biomass composite filler.

[0047] The solid-liquid ratio of the citric acid solution and the pretreated straw in step (2) is 1 g: 10 mL, and in the chitosan acetic acid solution in step (3), the solid-liquid ratio of chitosan and acetic acid solution is 1 g: 100 mL, and the mass concentration of the acetic acid solution is 3%.

[0048] The addition amount of the straw-based biomass composite filler in step (5) is 20 g per liter of sewage.

[0049] Comparative Example 1 Only the strain composition in the composite functional microbial agent is changed, and the rest of the raw materials and process steps are the same as in Example 1.

[0050] That is: The preparation method of the composite functional microbial agent is: inoculate Pseudomonas pinipestis, Microbacterium corchorusii and Bacillus licheniformis into LB culture medium respectively, and shake culture until the bacterial content is O.D 600 ≈3.0, then mix to obtain a mixed bacterial solution according to the volume ratio in Table 1, mix and adsorb the mixed bacterial solution with a carrier at a volume-mass ratio of 1 L: 1.5 kg, the carrier is composed of attapulgite, starch and calcium chloride at a mass ratio of 100:5:2; granulate the adsorbed material, and vacuum dry to a water content of ≤8%, to obtain the composite functional microbial agent, and the effective viable bacterial count in the composite functional microorganism is not less than 1×10 9 CFU / g.

[0051] Table 1 Strain composition (volume ratio) of Comparative Examples 1-9 composite functional microbial agent Comparative Example 10 In this comparative example, except that the straw-based biomass composite filler in step (5) is replaced with an equal amount of ordinary ceramsite filler, the rest of the raw materials and process steps are the same as in Example 1. That is: A purification treatment process for livestock breeding wastewater, comprising the following preparation steps: (1) Pretreatment: remove large suspended solids and impurities in the livestock breeding wastewater to be treated by a grating machine, then enter a sand trap for preliminary sedimentation, separate heavy particles such as sand and gravel, and reduce the subsequent treatment load; (2) Primary treatment: the pretreated wastewater is introduced into a hydrolysis acidification tank, the hydraulic retention time is 6 hours, and the original facultative microorganisms in the tank are used for preliminary fermentation decomposition; (3) Core microbial treatment: the effluent from the hydrolysis acidification tank is introduced into an aerobic reaction tank, the pH is adjusted to 6.5-7.5, 1% of the wastewater quality is added with a compound functional bacteria agent, intermittent aeration is adopted, aeration is carried out for 15 minutes, and reaction is carried out for 45 minutes, the hydraulic retention time is 12 hours; (4) Solid-liquid separation: the effluent from the aerobic reaction tank is introduced into a sedimentation tank, and is statically settled for 1 hour, and mud-water separation is realized by relying on the biological flocculation of microorganisms themselves; (5) Advanced treatment and disinfection: the supernatant from the sedimentation tank is introduced into a filter tank with ordinary ceramic filler for the last denitrification and phosphorus removal purification, the hydraulic retention time is controlled to be 1 hour, and finally ozone is used for disinfection treatment before discharge. The ozone dosage is controlled to be 10 mg / L.

[0052] The addition amount of the ordinary ceramic filler in step (5) is 10 g per liter of wastewater.

[0053] Performance test The degradation effects of Pseudomonas pinipresti, Microbacterium coriellii and Bacillus licheniformis on COD and ammonia nitrogen under different compositions are determined.

[0054] The simulated high-salt wastewater culture medium: ammonium chloride 8 g, anhydrous sodium acetate 2 g, magnesium sulfate heptahydrate 0.05 g, dipotassium hydrogen phosphate 0.2 g, sodium chloride 33 g, manganese sulfate tetrahydrate 0.01 g, ferrous sulfate 0.01 g, water 1 L, and the pH is adjusted to 7.2. After sterilization at 121℃ for 30 min, it is ready for use (the ammonia nitrogen content is 1027.3 mg / L, and the COD content is 1545 mg / L).

[0055] Preparation of bacterial suspension: Pseudomonas pinipresti, Microbacterium coriellii and Bacillus licheniformis are inoculated into LB liquid medium respectively, after 48 h of culture, 10 mL of culture solution is centrifuged at 6000 r / min for 10 min, and the bacterial body is washed with sterile water for three times. With sterile water as the reference, 4 mL of bacterial suspension is determined at 600 nm wavelength, and the result is taken as 1.0. Three kinds of bacterial liquid are obtained, and the bacterial suspension with different strain compositions is obtained by configuring the three kinds of bacterial liquid according to Table 1.

[0056] The obtained bacterial suspension was inoculated into 100 mL simulated sewage at an addition amount of 1%. Three parallel experiments were set up for each experimental group, and the results were averaged. The culture was carried out at 180 r / min and 30°C. The degradation effect of each strain on the simulated sewage was determined on the 5th day. The suspended solids had a certain influence on the test results, so when determining the COD, the digested sample was centrifuged at 8000 r / min for 5 min, and the supernatant was collected for determination of the COD value.

[0057] COD degradation rate (%) = (COD concentration of sewage before treatment - COD concentration of sewage after treatment) / COD concentration of sewage before treatment x 100%; NH4 + -N degradation rate (%) = (NH4 + -N content of sewage before treatment - NH4 + -N content of sewage after treatment) / NH4 + -N content of sewage before treatment x 100%; The test method refers to the relevant national standards, wherein the COD determination adopts the potassium dichromate method GB11914-89, and the ammonia nitrogen determination adopts the Nessler's reagent spectrophotometric method GB7479-87.

[0058] Table 2 Test results of simulated degradation effect From the data in Table 2, it can be seen that the purification treatment process of Example 1 of the present application has significant advantages in terms of COD degradation rate and ammonia nitrogen degradation rate, which respectively reach 78.9% and 90.5%, and are obviously superior to other comparative examples. This fully illustrates that the Pseudomonas pinipresti, Microbacterium corchorusii and Bacillus licheniformis in the composite functional bacterial agent have the best synergistic effect when mixed at a volume ratio of 1:1:1.

[0059] Flocculation effect test: Pseudomonas pinipresti, Microbacterium corchorusii and Bacillus licheniformis were respectively inoculated into 50 mL conical flasks containing 20 mL of flocculation fermentation medium, and cultured in a shaking bed at 30°C and 120 rpm for 3 days. The fermentation broth of the bacterial body was centrifuged at 8000 rpm for 15 min, and the supernatant was taken for determination of the flocculation rate.

[0060] Flocculation fermentation medium: glucose 10.0 g, magnesium sulfate 0.2 g, urea 0.5 g, potassium dihydrogen phosphate 2.0 g, yeast extract powder 0.5 g, dipotassium hydrogen phosphate 5.0 g, sodium chloride 33.0 g, pH 7.0-7.3, glucose 115°C sterilization 30 min, other ingredients 121°C, sterilization 20 min.

[0061] Different bacterial strains were mixed according to the strain ratios in Example 1 and Comparative Examples 1-9, and the flocculation effect of the mixture was measured. The test method was as follows: 200 mL of 4 g / L kaolin suspension, 2 mL of fermentation supernatant, and 300 µL of 10% calcium chloride solution were added to a 250 mL beaker, and the pH was adjusted to 7.3. A smart magnetic stirrer was used with a flocculation stirring program of 700 rpm for 1 min, 80 rpm for 10 min, and then allowed to stand for 5 min. After standing, the absorbance of the supernatant was measured at 550 nm. The control group used deionized water instead of fermentation supernatant, while other conditions remained the same as the experimental group. The flocculation rate was calculated using the formula shown. Each experimental group was repeated three times, and the average value was taken as the final result.

[0062] Flocculation rate (%) = (B - A) / B × 100% Where A is the absorbance of the supernatant of the experimental group and B is the absorbance of the supernatant of the control group.

[0063] Test results are as follows Figure 3 As shown. From Figure 3 The test results show that all three active bacterial strains of this invention have a certain flocculation effect, and the composite functional bacterial agent with the three strains mixed in a volume ratio of 1:1:1 exhibits the best flocculation performance, with a flocculation rate of [percentage missing]. This indicates that the three strains have a good synergistic effect at this ratio. Changing the strain composition to comparative ratios 1-9 disrupts the synergistic balance among the three strains, resulting in a certain degree of weakening in both pollutant removal and flocculation capabilities.

[0064] Actual wastewater treatment in aquaculture: Wastewater source: Wastewater discharged from a large pig farm in Lanling County, Linyi City, Shandong Province. The wastewater was treated according to the methods of Examples 1-3 and Comparative Examples 1-10 of this invention.

[0065] Detection methods Water quality indicators were tested according to national standard methods, as shown in Table 3: Table 3 Water quality testing indicators and methods The test results are shown in Table 4: Table 4 Water purification results Table 5 Water purification effect From the data of Tables 4-5, we can see that the embodiments 1-3 of the present application exhibit significant purification effect in actual aquaculture wastewater treatment, especially in COD, BOD, total phosphorus, total nitrogen, ammonia nitrogen, suspended solids and heavy metals and other key indicators, which all show better treatment capacity than the comparative examples. Taking Example 1 as an example, the COD decreased from 6900.2 mg / L before treatment to 162.3 mg / L, with a removal rate of more than 90%; the ammonia nitrogen decreased from 455.1 mg / L to 20.3 mg / L, with a removal rate of 95.5%; the number of fecal coliform bacteria also decreased from 8.5×10 7 mg / L to 5000 / L, indicating that the process has high sterilization efficiency. At the same time, in terms of heavy metal removal, the concentrations of copper, zinc, manganese, cadmium, hexavalent chromium and arsenic all decreased significantly, fully meeting the national discharge standards.

[0066] It is worth noting that although Comparative Examples 1-9 also used different strain combinations for treatment, due to the deviation of the strain ratio from the optimal synergistic range, their purification effect was significantly weaker than the embodiments. This further verifies the superior performance of Pseudomonas pinipeti, Comamonas acidovorans and Bacillus licheniformis mixed at a volume ratio of 1:1:1.

[0067] In summary, the composite functional bacterial agent and its supporting process provided by the present application not only can effectively degrade organic pollutants, but also have good flocculation ability and heavy metal removal effect, and are suitable for high salinity and high pollution load in actual aquaculture wastewater treatment scenarios, providing reliable technical support for the sustainable development of the livestock breeding industry.

[0068] It should be noted that the above examples are only part of the preferred modes of implementing the present application, not all. Obviously, based on the above examples of the present application, all other examples obtained by a person of ordinary skill in the art without creative labor should fall within the scope of protection of the present application.

Claims

1. A purification and treatment process for livestock breeding wastewater, characterized in that, The preparation steps include the following: (1) Pretreatment: The livestock wastewater to be treated is removed by a bar screen to remove large suspended solids and impurities, and then enters a grit chamber for preliminary sedimentation to separate heavy particles such as sand and gravel, thereby reducing the load on subsequent treatment. (2) Primary treatment: The pretreated wastewater is introduced into the hydrolysis acidification tank, with a hydraulic retention time of 6-8 hours, and the facultative microorganisms in the tank are used for preliminary fermentation and decomposition. (3) Core microbial treatment: The effluent from the hydrolysis acidification tank is introduced into the aerobic reaction tank, the pH is adjusted to 6.5-7.5, and compound functional bacterial agent is added at 1-3% of the sewage mass. Intermittent aeration is adopted, aeration is carried out for 15 minutes, and the reaction is stopped for 45 minutes. The hydraulic retention time is 12-18 hours. (4) Solid-liquid separation: The effluent from the aerobic reaction tank enters the sedimentation tank and is allowed to settle for 1-2 hours. The mud and water are separated by the bioflocculation of the microorganisms themselves. (5) Deep treatment and disinfection: The supernatant from the sedimentation tank enters the filter tank filled with bacterial bran-based biomass composite packing for final denitrification and phosphorus removal purification. The hydraulic retention time is controlled at 1-2 hours. Finally, it is discharged after disinfection treatment with ultraviolet light or ozone.

2. The purification and treatment process for livestock breeding wastewater according to claim 1, characterized in that, In step (3), the compound functional microbial agent contains Pseudomonas hazel, Microbacterium keratolyticum and Bacillus licheniformis, with a volume ratio of 1:1:

1.

3. The purification and treatment process for livestock breeding wastewater according to claim 2, characterized in that, The strain number of *Pseudomonas hazel* is CGMCC No. 1.3819, the strain number of *Microbacterium keratolyticum* is CGMCC No. 1.6312, and the preservation number of *Bacillus licheniformis* is CGMCC No. 79241. They are deposited at the China General Microbiological Culture Collection Center, located at No. 3, Courtyard 1, Beichen West Road, Chaoyang District, Beijing.

4. The purification and treatment process for livestock breeding wastewater according to claim 3, characterized in that, The preparation method of the compound functional microbial agent is as follows: *Pseudomonas hazelnutans*, *Microbacterium keratolyticum*, and *Bacillus licheniformis* are inoculated into LB medium and cultured with shaking until the bacterial count reaches OD200. 600 The volume ratio of the bacterial solution to the carrier was approximately 3.

0. The mixed bacterial solution was then prepared by mixing the carrier with the carrier at a volume-to-mass ratio of 1L:1.5kg. The carrier consisted of attapulgite clay, starch, and calcium chloride at a mass ratio of 100:5:

2. The adsorbed material was granulated and vacuum-dried until the moisture content was ≤8%, thus obtaining the composite functional microbial agent. The effective viable count of the composite functional microorganisms was not less than 1×10⁻⁶. 9 CFU / g.

5. The purification and treatment process for livestock breeding wastewater according to claim 1, characterized in that, Step (5) The preparation method of the bacterial bran-based biomass composite filler is as follows: (1) Raw material pretreatment: Fresh mushroom substrate taken from enoki mushroom or king oyster mushroom factories is crushed and screened to obtain 40-60 mesh particles. The substrate is repeatedly rinsed with water until the water is clear to remove soluble impurities. It is then dried at 80℃ to constant weight to obtain pretreated mushroom substrate. (2) Acid washing and activation: The pretreated bacterial bran was placed in a 5% citric acid solution and shaken at 60℃ and 150 r / min for 2 hours. After the reaction was completed, it was filtered, washed with deionized water until neutral, and dried. (3) Iron-chitosan loading modification: Prepare a 1.0 mol / L FeCl3 solution and a chitosan acetic acid solution; immerse the acid-washed mushroom bran in the FeCl3 solution at a solid-liquid ratio of 1g:15mL, slowly add the above chitosan solution to the system, the mass ratio of chitosan to mushroom bran is 1:20, and stir slowly at 45℃ for 4 hours; after the reaction is completed, filter, wash the obtained solid with deionized water 2-3 times, vacuum dry at 60℃, and cool to obtain the mushroom bran-based biomass composite filler.

6. The purification and treatment process for livestock breeding wastewater according to claim 5, characterized in that, In step (2), the solid-liquid ratio of citric acid solution and pretreated bacterial bran is 1g:10mL. In step (3), the solid-liquid ratio of chitosan and acetic acid solution is 1g:100mL, and the mass concentration of acetic acid solution is 3%.

7. The purification and treatment process for livestock breeding wastewater according to claim 1, characterized in that, The amount of bacterial bran-based biomass composite filler added in step (5) is 10-20g per liter of sewage.

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