A method for purifying mixed sewage from animal husbandry

Abstract

The present invention discloses a method for purifying mixed sewage from animal husbandry, and belongs to the field of environmental protection technology. The present invention includes solid-liquid separation and sedimentation treatment, flotation treatment, anaerobic treatment, aerobic treatment, flocculation treatment, separation treatment and disinfection treatment for the treatment of aquaculture sewage. First, the present invention uses an anaerobic-aerobic two-step microbial treatment process to achieve effective decomposition and removal of organic matter and heavy metal ions in sewage, and then through modified zeolite-type composite flocculant treatment and ozone treatment, the oxidative decolorization and sterilization treatment of the wastewater are completed. The final effluent water quality is clear, pollutants are effectively removed, the treatment efficiency is high, the labor cost is low, it is green and pollution-free, and has practical application value.

Description

Technical Field

[0001] The invention belongs to the technical field of environmental protection, and in particular relates to a method for purifying mixed sewage from animal husbandry. Background Art

[0002] The livestock and poultry industry is an important part of agriculture and rural economy. The environmental pollution caused by the vigorous development of livestock and poultry breeding is becoming increasingly serious. At present, the livestock and poultry breeding wastewater discharged by large-scale farms every day is large and concentrated, and contains a large number of pollutants, such as CODcr, ammonia nitrogen, heavy metals, residual veterinary drugs and a large number of pathogens. If it is discharged directly without treatment, it will cause serious pollution.

[0003] For example, aquaculture wastewater is a high-concentration organic wastewater containing a large number of pathogens. After a large amount of organic matter enters the water body, the decomposition of the organic matter will consume a large amount of dissolved oxygen in the water, making the water body stink and leading to the death of a large number of aquatic organisms; nitrogen and phosphorus can cause eutrophication of the water body.

[0004] Livestock and poultry wastewater will produce a large amount of NH under anaerobic conditions. 3 , H 2 S and other foul-smelling gases, which will affect and endanger the health of breeders and surrounding residents.

[0005] The wastewater from livestock and poultry farming contains a lot of nutrients such as nitrogen, phosphorus, and potassium. If it is directly, continuously, and excessively applied without any treatment, it will have an adverse effect on the growth of soil and crops, such as reducing crop yields, delaying maturity, and affecting the production of subsequent crops. Therefore, it is very necessary to effectively treat livestock wastewater before discharging it.

[0006] At present, the current livestock and poultry wastewater treatment technologies are mainly anaerobic treatment technology, aerobic treatment technology, anaerobic-aerobic combined treatment technology and physical and chemical treatment technology, but these livestock and poultry wastewater treatment technologies also have disadvantages such as secondary pollution and large capital investment. In addition, there are also some existing technologies that use some equipment to treat sewage, such as patents with publication numbers CN112591819A and CN110282822A, but these technologies rely on complex equipment for treatment, which increases the difficulty and cost of treatment, has a low market application rate, and has not been effectively implemented.

[0007] Therefore, developing a highly efficient and environmentally friendly method for purifying livestock breeding wastewater is a technical problem that needs to be solved urgently. Summary of the invention

[0008] The present invention aims at the problems existing in the prior art and provides an efficient and environmentally friendly sewage treatment process, which adopts efficient anaerobic treatment microorganisms and modified flocculants to achieve efficient removal of nitrogen, phosphorus and COD in livestock breeding sewage.

[0009] In order to achieve the above technical objectives, the technical solution adopted by the present invention is:

[0010] A method for purifying mixed sewage from livestock breeding, comprising the following steps:

[0011] (1) Solid-liquid separation and sedimentation treatment: The wastewater to be treated is sent to a solid-liquid separator for solid-liquid separation. After solid-liquid separation, the wastewater is introduced into a primary sedimentation tank and allowed to stand for 1-2 hours for preliminary adsorption and sedimentation filtration;

[0012] (2) Flotation treatment: After primary sedimentation and filtration, the sewage enters the flotation treatment tank, where a large number of tiny bubbles are generated through the flotation principle. The tiny bubbles absorb the fine particles in the sewage and remove the micro-particles in the aquaculture sewage;

[0013] (3) Anaerobic treatment: The wastewater treated with flotation is introduced into the anaerobic tank, the pH of the system is adjusted to 6.5-7.5, and anaerobic microbial agents of 5% of the wastewater mass are added for anaerobic treatment. The dissolved oxygen content in the anaerobic treatment tank is controlled below 0.5 mg / L. The anaerobic treatment time is 8-10 hours. After the treatment, the wastewater is allowed to settle for 1-2 hours.

[0014] (4) Aerobic treatment: The anaerobic treated sewage is introduced into the aerobic tank, the pH of the system is adjusted to 6.5-7.5, and aerobic microbial agents of 5% of the sewage mass are added for aerobic fermentation. The aerobic fermentation time is 3-5 hours, and the treatment is completed and allowed to settle for 1-2 hours;

[0015] (5) Flocculation treatment: The aerobic treated sewage is introduced into the flocculation tank, and a modified flocculant is added at a rate of 10-20 g / t. The flocculation and adsorption treatment time is 1-2 h;

[0016] (6) Separation treatment: The wastewater after flocculation treatment is separated into solid and liquid by a centrifuge to remove solid matter, and the liquid is discharged and collected in a disinfection tank;

[0017] (7) Disinfection treatment: Use ozone to sterilize and disinfect the wastewater after flocculation treatment before discharge.

[0018] Furthermore, a filter filler is laid at the bottom of the primary sedimentation tank with a thickness of 50-70 cm. The filter filler is natural river sand with a fineness of 1-3 mm.

[0019] Furthermore, the anaerobic microbial agent in step (3) comprises a functional microorganism and a carrier, wherein the functional microorganism comprises Pseudomonas mendocinae ( Pseudomonas mendocina ) and Pseudomonas stutzeri ( Pseudomonas stutzeri), the volume ratio of the two is 1:1; the preparation method of the anaerobic microbial agent is: activate Pseudomonas mendocinae and Pseudomonas stutzeri respectively and inoculate them into the fermentation medium for cultivation at a temperature of 28-30°C, and cultivate them to a bacterial concentration of ≥3×10 8 / mL, terminate the cultivation, and obtain the fermentation broth of the two bacteria, mix the fermentation broths of the two bacteria in a volume ratio of 1:1 to obtain a mixed bacterial solution, add a carrier to the mixed bacterial solution in a solid-liquid ratio of 10mL:100g, fully mix and adsorb, and then dry to obtain an anaerobic treatment microbial agent.

[0020] Furthermore, the fermentation medium is composed of: 10 g glucose, 0.5 g yeast extract, 0.5 g urea, 2 HPO 4 5g, KH 2 PO 4 2g, NaCl 0.1g, MgSO 4 7H 2 O2g, double distilled water to 1000mL, pH adjusted to 6.5-7.5.

[0021] Furthermore, the strain number of the Pseudomonas mendocinae is CGMCC No.1.8049, purchased from the General Microbiology Center of China National Microorganism Culture Collection Administration (CGMCC), and the original preservation time is May 8, 2008; the strain number of the Pseudomonas stutzeri is CGMCC No.1.15316, purchased from the General Microbiology Center of China National Microorganism Culture Collection Administration (CGMCC), and the original preservation time is June 15, 2015. Both strains selected in the present invention can be queried and publicly purchased through the strain catalog of the General Microbiology Center of China National Microorganism Culture Collection Administration (CGMCC), without the need for repeated biological preservation.

[0022] Furthermore, the carrier comprises diatomaceous earth, sodium alginate, chitosan and sucrose in a mass ratio of (50-100):(1-5):(0.5-1.5):(1-5).

[0023] Furthermore, the aerobic microbial agent in step (4) comprises Bacillus mucilaginosus, Bacillus megaterium and Bacillus amyloliquefaciens, and the mass ratio of the three is 1:1:1.

[0024] Furthermore, the Bacillus mucilaginosus, Bacillus megaterium and Bacillus amyloliquefaciens in the aerobic microbial agent can be commercially available bacterial powders. The three bacterial powders of the present invention are all purchased from Henan Xin Yangshao Bioenzyme Preparation Co., Ltd., and the effective live bacteria count is 10 billion CFU / g.

[0025] Furthermore, during the aerobic treatment in step (4), aeration is performed at an air-water ratio of 15:1, once per hour, each aeration time is 10 minutes, and a total of 3-5 times.

[0026] Furthermore, the preparation method of the modified flocculant in step (5) is:

[0027] (1) Weighing 10 g of zeolite, placing it in 100 mL of a sodium chloride solution with a concentration of 30-60 g / L, shaking it at 45-50° C. and an oscillation frequency of 150-200 r / min for 30-60 min, washing the zeolite to neutrality after shaking, drying it at 100-105° C., placing it in a desiccator to cool to room temperature and then setting it aside;

[0028] (2) Take 10 g of the zeolite obtained in step (1) and place it in a container, add 20% of the mass of zeolite polyaluminium chloride and 20% of the mass of zeolite polyaluminium ferrosilicate, add 100 mL of deionized water and stir to mix evenly, let it stand for 30 min, put it in a constant temperature drying oven, dry it at 55-65°C to constant weight, take it out and let it stand to cool, and obtain a modified flocculant.

[0029] Furthermore, in step (6), the ozone treatment time is 30-35 minutes, and the ozone dosage is 5-10 mg / L.

[0030] Beneficial effects:

[0031] (1) First, the present invention uses an anaerobic-aerobic two-step microbial treatment process, in which two highly efficient anaerobic bacteria, Pseudomonas mendocinae and Pseudomonas stutzeri, are selected. Pseudomonas mendocinae can reduce the inorganic nitrogen content in the water body through nitrification and nitrogen fixation and denitrification reduction, and can also hydrolyze and convert complex organic matter into simple organic matter (such as organic acids, alcohols, aldehydes, etc.). This step is to decompose large molecular organic matter into small molecules or soluble substances, making them easy to be further degraded by microorganisms in the subsequent stage; then Pseudomonas stutzeri further converts these small molecular organic substances into methane and carbon dioxide to complete the entire anaerobic digestion process. The two are mixed in equal proportions and work synergistically to achieve efficient degradation of organic matter, ammonia nitrogen and other substances in aquaculture wastewater. At the same time, the surface of microbial cells has a large number of active groups (such as carboxyl, carbonyl, hydroxyl, etc.), which can coordinate or chelate with heavy metal ions, thereby achieving rapid adsorption and fixation of heavy metal elements.

[0032] (2) During the anaerobic treatment stage, anaerobic microorganisms decompose most of the pollutants, and then commercially available bacterial powder is used for secondary fermentation treatment to further degrade and transform organic matter, degrade residual nitrate and nitrite pollutants, reduce and eliminate pollutants such as ammonia nitrogen and hydrogen sulfide in the water, and further purify the water.

[0033] (3) Finally, the modified flocculant is used to further treat the aerobic treated sewage, which has multiple functions such as adsorption, flocculation, and purification. First, the present invention uses sodium chloride solution to modify the surface of zeolite. There are many cavities formed by aluminum-silicon tetrahedrons in natural zeolite. These cavities are the action points of ion adsorption. + Solution modification, Na with smaller ionic radius + Replaces the Ca2+ ion with a larger radius in the original hole 2+ and Mg 2+ , which increases the pore volume and makes the voids obvious, thereby improving the overall adsorption rate of the material, and has a good adsorption and fixation effect on heavy metal elements, nitrogen, phosphorus and other substances; secondly, the present invention uses polyaluminum chloride and polyaluminum ferrosilicate to jointly modify the zeolite, and the surface after the combined modification presents a lamellar villi structure with regular arrangement, so that the composite flocculation material exhibits a better flocculation effect, and the purification flocculation effect is doubled.

[0034] (4) Finally, after ozone treatment, the wastewater is oxidized, decolorized and sterilized. The final effluent water quality is clear, and pollutants are effectively removed. The treatment efficiency is high, the labor cost is low, it is green and pollution-free, and has practical application value. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 This is the result of the flocculation rate test of different flocculants;

[0036] Figure 2 Surface electron micrographs of the original zeolite, the modified flocculant of Example 1 of the present invention, and the modified flocculants of Comparative Examples 5-6, wherein (A) is the original zeolite, (B) is Example 1, (C) is Comparative Example 5, and (D) is Comparative Example 6. DETAILED DESCRIPTION

[0037] The technical solution of the present invention is further described below in conjunction with specific embodiments, but is not limited thereto.

[0038] Example 1

[0039] A method for purifying mixed sewage from livestock breeding includes the following steps:

[0040] (1) Solid-liquid separation and sedimentation treatment: The wastewater to be treated is sent to a solid-liquid separator for solid-liquid separation. After solid-liquid separation, the wastewater is introduced into a primary sedimentation tank and allowed to stand for 1 hour for preliminary adsorption and sedimentation filtration;

[0041] (2) Flotation treatment: After primary sedimentation and filtration, the sewage enters the flotation treatment tank, where a large number of tiny bubbles are generated through the flotation principle. The tiny bubbles absorb the fine particles in the sewage and remove the micro-particles in the aquaculture sewage;

[0042] (3) Anaerobic treatment: The wastewater treated with flotation is introduced into the anaerobic tank, the pH of the system is adjusted to 6.5-7.5, and anaerobic microbial agents of 5% of the wastewater mass are added for anaerobic treatment. The dissolved oxygen content in the anaerobic treatment tank is controlled below 0.5 mg / L. The anaerobic treatment time is 8 hours, and the treatment is completed and allowed to settle for 1 hour;

[0043] (4) Aerobic treatment: The anaerobic treated sewage is introduced into the aerobic tank, the pH of the system is adjusted to 6.5-7.5, and aerobic microbial agents of 5% of the sewage mass are added for aerobic fermentation. The aerobic fermentation time is 3 hours, and the treatment is completed and allowed to settle for 1 hour;

[0044] (5) Flocculation treatment: The aerobic treated sewage is introduced into the flocculation tank, and the modified flocculant is added at a rate of 10 g / t. The flocculation and adsorption treatment time is 1 h;

[0045] (6) Separation treatment: The wastewater after flocculation treatment is separated into solid and liquid by a centrifuge to remove solid matter, and the liquid is discharged and collected in a disinfection tank;

[0046] (7) Disinfection treatment: Use ozone to sterilize and disinfect the wastewater after flocculation treatment before discharge.

[0047] The bottom of the primary sedimentation tank is paved with filter filler with a thickness of 50 cm. The filter filler is natural river sand with a fineness of 1-3 mm.

[0048] Step (3) the anaerobic microbial agent comprises a functional microorganism and a carrier, wherein the functional microorganism comprises Pseudomonas mendocinae ( Pseudomonas mendocina ) and Pseudomonas stutzeri ( Pseudomonas stutzeri ), the volume ratio of the two is 1:1; the preparation method of the anaerobic microbial agent is: activate Pseudomonas mendocinae and Pseudomonas stutzeri respectively and inoculate them into the fermentation medium for cultivation at a temperature of 28-30°C, and cultivate them to a bacterial concentration of ≥3×10 8 / mL, terminate the cultivation, and obtain the fermentation broth of the two bacteria, mix the fermentation broths of the two bacteria in a volume ratio of 1:1 to obtain a mixed bacterial solution, add a carrier to the mixed bacterial solution in a solid-liquid ratio of 10mL:100g, fully mix and adsorb, and then dry to obtain an anaerobic treatment microbial agent.

[0049] The fermentation medium is composed of: 10 g glucose, 0.5 g yeast extract, 0.5 g urea, 2 HPO 4 5g, KH 2 PO 4 2g, NaCl 0.1g, MgSO 4 7H 2 O2g, double distilled water to 1000mL, pH adjusted to 6.5-7.5.

[0050] The strain number of the Pseudomonas mendocinae is CGMCC No.1.8049, purchased from the General Microbiological Center of China National Microbiological Culture Collection (CGMCC), and the original preservation time is May 8, 2008; the strain number of the Pseudomonas stutzeri is CGMCC No.1.15316, purchased from the General Microbiological Center of China National Microbiological Culture Collection (CGMCC), and the original preservation time is June 15, 2015. Both strains selected in the present invention can be queried and publicly purchased through the strain catalog of the General Microbiological Center of China National Microbiological Culture Collection (CGMCC), without the need for repeated biological preservation.

[0051] The carrier comprises diatomaceous earth, sodium alginate, chitosan and sucrose in a mass ratio of 100:1:0.5:1.

[0052] The aerobic microbial agent in step (4) comprises Bacillus mucilaginosus, Bacillus megaterium and Bacillus amyloliquefaciens, and the mass ratio of the three is 1:1:1.

[0053] The Bacillus mucilaginosus, Bacillus megaterium and Bacillus amyloliquefaciens in the aerobic microbial agent can be commercially available bacterial powders. The three bacterial powders in this embodiment are all purchased from Henan Xin Yangshao Bio-enzyme Preparation Co., Ltd., and the effective live bacteria count is 10 billion CFU / g.

[0054] During the aerobic treatment in step (4), aeration was performed at an air-water ratio of 15:1, once per hour, each aeration time was 10 minutes, and a total of 3 times.

[0055] The preparation method of the modified flocculant in step (5) is:

[0056] (1) Weighing 10 g of zeolite, placing it in 100 mL of a 30 g / L sodium chloride solution, shaking it at 45-50° C. and an oscillation frequency of 150 r / min for 30 min, washing the zeolite to neutrality after shaking, drying it at 100-105° C., placing it in a desiccator to cool to room temperature, and then setting it aside;

[0057] (2) Take 10 g of the zeolite obtained in step (1) and place it in a container, add 20% of the mass of zeolite polyaluminium chloride and 20% of the mass of zeolite polyaluminium ferrosilicate, add 100 mL of deionized water and stir to mix evenly, let it stand for 30 min, put it in a constant temperature drying oven, dry it at 55-65°C to constant weight, take it out and let it stand to cool, and obtain a modified flocculant.

[0058] The ozone treatment time in step (6) is 30 min, and the ozone dosage is 5 mg / L.

[0059] Example 2

[0060] A method for purifying mixed sewage from livestock breeding, comprising the following steps:

[0061] (1) Solid-liquid separation and sedimentation treatment: The wastewater to be treated is sent to a solid-liquid separator for solid-liquid separation. After solid-liquid separation, the wastewater is introduced into a primary sedimentation tank and allowed to stand for 1-2 hours for preliminary adsorption and sedimentation filtration;

[0062] (2) Flotation treatment: After primary sedimentation and filtration, the sewage enters the flotation treatment tank, where a large number of tiny bubbles are generated through the flotation principle. The tiny bubbles absorb the fine particles in the sewage and remove the micro-particles in the aquaculture sewage;

[0063] (3) Anaerobic treatment: The wastewater treated with flotation is introduced into the anaerobic tank, the pH of the system is adjusted to 6.5-7.5, and anaerobic microbial agents of 5% of the wastewater mass are added for anaerobic treatment. The dissolved oxygen content in the anaerobic treatment tank is controlled below 0.5 mg / L. The anaerobic treatment time is 9 hours, and the treatment is completed and allowed to settle for 1.5 hours;

[0064] (4) Aerobic treatment: The anaerobic treated sewage is introduced into the aerobic tank, the pH of the system is adjusted to 6.5-7.5, and aerobic microbial agents of 5% of the sewage mass are added for aerobic fermentation. The aerobic fermentation time is 4 hours, and the treatment is completed and allowed to settle for 1.5 hours;

[0065] (5) Flocculation treatment: The aerobic treated sewage was introduced into the flocculation tank, and the modified flocculant was added at a rate of 15 g / t. The treatment time of flocculation and adsorption treatment was 1.5 h;

[0066] (6) Separation treatment: The wastewater after flocculation treatment is separated into solid and liquid by a centrifuge to remove solid matter, and the liquid is discharged and collected in a disinfection tank;

[0067] (7) Disinfection treatment: Use ozone to sterilize and disinfect the wastewater after flocculation treatment before discharge.

[0068] The bottom of the primary sedimentation tank is paved with filter filler with a thickness of 60 cm. The filter filler is natural river sand with a fineness of 1-3 mm.

[0069] Step (3) the anaerobic microbial agent comprises a functional microorganism and a carrier, wherein the functional microorganism comprises Pseudomonas mendocinae ( Pseudomonas mendocina ) and Pseudomonas stutzeri ( Pseudomonas stutzeri ), the volume ratio of the two is 1:1; the preparation method of the anaerobic microbial agent is: activate Pseudomonas mendocinae and Pseudomonas stutzeri respectively and inoculate them into the fermentation medium for cultivation at a temperature of 28-30°C, and cultivate them to a bacterial concentration of ≥3×10 8 / mL, terminate the cultivation, and obtain the fermentation broth of the two bacteria, mix the fermentation broths of the two bacteria in a volume ratio of 1:1 to obtain a mixed bacterial solution, add a carrier to the mixed bacterial solution in a solid-liquid ratio of 10mL:100g, fully mix and adsorb, and then dry to obtain an anaerobic treatment microbial agent.

[0070] The fermentation medium is composed of: 10 g glucose, 0.5 g yeast extract, 0.5 g urea, 2 HPO 4 5g, KH 2 PO 4 2g, NaCl 0.1g, MgSO 4 7H 2 O2g, double distilled water to 1000mL, pH adjusted to 6.5-7.5.

[0071] The strain number of the Pseudomonas mendocinae is CGMCC No.1.8049, purchased from the General Microbiological Center of China National Microbiological Culture Collection (CGMCC), and the original preservation time is May 8, 2008; the strain number of the Pseudomonas stutzeri is CGMCC No.1.15316, purchased from the General Microbiological Center of China National Microbiological Culture Collection (CGMCC), and the original preservation time is June 15, 2015. Both strains selected in the present invention can be queried and publicly purchased through the strain catalog of the General Microbiological Center of China National Microbiological Culture Collection (CGMCC), without the need for repeated biological preservation.

[0072] The carrier comprises diatomaceous earth, sodium alginate, chitosan and sucrose in a mass ratio of 70:3:1:3.

[0073] The aerobic microbial agent in step (4) comprises Bacillus mucilaginosus, Bacillus megaterium and Bacillus amyloliquefaciens, and the mass ratio of the three is 1:1:1.

[0074] The Bacillus mucilaginosus, Bacillus megaterium and Bacillus amyloliquefaciens in the aerobic microbial agent can be commercially available bacterial powders. The three bacterial powders in this embodiment are all purchased from Henan Xin Yangshao Bio-enzyme Preparation Co., Ltd., and the effective live bacteria count is 10 billion CFU / g.

[0075] During the aerobic treatment in step (4), aeration was performed at an air-water ratio of 15:1, once per hour, each aeration time was 10 minutes, and a total of 3 times.

[0076] The preparation method of the modified flocculant in step (5) is:

[0077] (1) Weighing 10 g of zeolite, placing it in 100 mL of a sodium chloride solution with a concentration of 45 g / L, and shaking it at 45-50° C. and an oscillation frequency of 200 r / min for 50 min. After the shaking, washing the zeolite to neutrality, drying it at 100-105° C., placing it in a desiccator to cool to room temperature, and then using it for later use;

[0078] (2) Take 10 g of the zeolite obtained in step (1) and place it in a container, add 20% of the mass of zeolite polyaluminium chloride and 20% of the mass of zeolite polyaluminium ferrosilicate, add 100 mL of deionized water and stir to mix evenly, let it stand for 30 min, put it in a constant temperature drying oven, dry it at 55-65°C to constant weight, take it out and let it stand to cool, and obtain a modified flocculant.

[0079] The ozone treatment time in step (6) is 35 min, and the ozone dosage is 10 mg / L.

[0080] Example 3

[0081] A method for purifying mixed sewage from livestock breeding includes the following steps:

[0082] (1) Solid-liquid separation and sedimentation treatment: The wastewater to be treated is sent to a solid-liquid separator for solid-liquid separation. After solid-liquid separation, the wastewater is introduced into a primary sedimentation tank and allowed to stand for 2 hours for preliminary adsorption and sedimentation filtration;

[0083] (2) Flotation treatment: After primary sedimentation and filtration, the sewage enters the flotation treatment tank, where a large number of tiny bubbles are generated through the flotation principle. The tiny bubbles absorb the fine particles in the sewage and remove the micro-particles in the aquaculture sewage;

[0084] (3) Anaerobic treatment: The wastewater treated with flotation is introduced into the anaerobic tank, the pH of the system is adjusted to 6.5-7.5, and anaerobic microbial agents of 5% of the wastewater mass are added for anaerobic treatment. The dissolved oxygen content in the anaerobic treatment tank is controlled below 0.5 mg / L. The anaerobic treatment time is 10 hours, and the treatment is completed and allowed to settle for 2 hours;

[0085] (4) Aerobic treatment: The anaerobic treated sewage is introduced into the aerobic tank, the pH of the system is adjusted to 6.5-7.5, and aerobic microbial agents of 5% of the sewage mass are added for aerobic fermentation. The aerobic fermentation time is 5 hours, and the treatment is completed and allowed to settle for 2 hours;

[0086] (5) Flocculation treatment: The aerobic treated sewage is introduced into the flocculation tank, and a modified flocculant is added at a rate of 20 g / t. The flocculation and adsorption treatment time is 2 h;

[0087] (6) Separation treatment: The wastewater after flocculation treatment is separated into solid and liquid by a centrifuge to remove solid matter, and the liquid is discharged and collected in a disinfection tank;

[0088] (7) Disinfection treatment: Use ozone to sterilize and disinfect the wastewater after flocculation treatment before discharge.

[0089] The bottom of the primary sedimentation tank is paved with filter filler with a thickness of 70 cm. The filter filler is natural river sand with a fineness of 1-3 mm.

[0090] Step (3) the anaerobic microbial agent comprises a functional microorganism and a carrier, wherein the functional microorganism comprises Pseudomonas mendocinae ( Pseudomonas mendocina ) and Pseudomonas stutzeri ( Pseudomonas stutzeri ), the volume ratio of the two is 1:1; the preparation method of the anaerobic microbial agent is: activate Pseudomonas mendocinae and Pseudomonas stutzeri respectively and inoculate them into the fermentation medium for cultivation at a temperature of 28-30°C, and cultivate them to a bacterial concentration of ≥3×10 8 / mL, terminate the cultivation, and obtain the fermentation broth of the two bacteria, mix the fermentation broths of the two bacteria in a volume ratio of 1:1 to obtain a mixed bacterial solution, add a carrier to the mixed bacterial solution in a solid-liquid ratio of 10mL:100g, fully mix and adsorb, and then dry to obtain an anaerobic treatment microbial agent.

[0091] The fermentation medium is composed of: 10 g glucose, 0.5 g yeast extract, 0.5 g urea, 2 HPO 4 5g, KH 2 PO 4 2g, NaCl 0.1g, MgSO 4 7H 2 O2g, double distilled water to 1000mL, pH adjusted to 6.5-7.5.

[0092] The strain number of the Pseudomonas mendocinae is CGMCC No.1.8049, purchased from the General Microbiological Center of China National Microbiological Culture Collection (CGMCC), and the original preservation time is May 8, 2008; the strain number of the Pseudomonas stutzeri is CGMCC No.1.15316, purchased from the General Microbiological Center of China National Microbiological Culture Collection (CGMCC), and the original preservation time is June 15, 2015. Both strains selected in the present invention can be queried and publicly purchased through the strain catalog of the General Microbiological Center of China National Microbiological Culture Collection (CGMCC), without the need for repeated biological preservation.

[0093] The carrier comprises diatomaceous earth, sodium alginate, chitosan and sucrose in a mass ratio of 50:5:1.5:5.

[0094] The aerobic microbial agent in step (4) comprises Bacillus mucilaginosus, Bacillus megaterium and Bacillus amyloliquefaciens, and the mass ratio of the three is 1:1:1.

[0095] The Bacillus mucilaginosus, Bacillus megaterium and Bacillus amyloliquefaciens in the aerobic microbial agent can be commercially available bacterial powders. The three bacterial powders in this embodiment are all purchased from Henan Xin Yangshao Bio-enzyme Preparation Co., Ltd., and the effective live bacteria count is 10 billion CFU / g.

[0096] During the aerobic treatment in step (4), aeration was performed at an air-water ratio of 15:1, once per hour, each aeration time was 10 minutes, and a total of 5 times.

[0097] The preparation method of the modified flocculant in step (5) is:

[0098] (1) Weighing 10 g of zeolite, placing it in 100 mL of a 60 g / L sodium chloride solution, shaking it at 45-50° C. and an oscillation frequency of 200 r / min for 60 min, washing the zeolite to neutrality after the shaking, drying it at 100-105° C., placing it in a desiccator to cool to room temperature, and then setting it aside;

[0099] (2) Take 10 g of the zeolite obtained in step (1) and place it in a container, add 20% of the mass of zeolite polyaluminium chloride and 20% of the mass of zeolite polyaluminium ferrosilicate, add 100 mL of deionized water and stir to mix evenly, let it stand for 30 min, put it in a constant temperature drying oven, dry it at 55-65°C to constant weight, take it out and let it stand to cool, and obtain a modified flocculant.

[0100] The ozone treatment time in step (6) is 35 min, and the ozone dosage is 10 mg / L.

[0101] Comparative Example 1

[0102] A method for purifying mixed sewage from livestock breeding includes the following steps:

[0103] (1) Solid-liquid separation and sedimentation treatment: The wastewater to be treated is sent to a solid-liquid separator for solid-liquid separation. After solid-liquid separation, the wastewater is introduced into a primary sedimentation tank and allowed to stand for 1 hour for preliminary adsorption and sedimentation filtration;

[0104] (2) Flotation treatment: After primary sedimentation and filtration, the sewage enters the flotation treatment tank, where a large number of tiny bubbles are generated through the flotation principle. The tiny bubbles absorb the fine particles in the sewage and remove the micro-particles in the aquaculture sewage;

[0105] (3) Anaerobic treatment: The wastewater treated with flotation is introduced into the anaerobic tank, the pH of the system is adjusted to 6.5-7.5, and anaerobic microbial agents of 5% of the wastewater mass are added for anaerobic treatment. The dissolved oxygen content in the anaerobic treatment tank is controlled below 0.5 mg / L. The anaerobic treatment time is 8 hours, and the treatment is completed and allowed to settle for 1 hour;

[0106] (4) Aerobic treatment: The anaerobic treated sewage is introduced into the aerobic tank, the pH of the system is adjusted to 6.5-7.5, and aerobic microbial agents of 5% of the sewage mass are added for aerobic fermentation. The aerobic fermentation time is 3 hours, and the treatment is completed and allowed to settle for 1 hour;

[0107] (5) Flocculation treatment: The aerobic treated sewage is introduced into the flocculation tank, and the modified flocculant is added at a rate of 10 g / t. The flocculation and adsorption treatment time is 1 h;

[0108] (6) Separation treatment: The wastewater after flocculation treatment is separated into solid and liquid by a centrifuge to remove solid matter, and the liquid is discharged and collected in a disinfection tank;

[0109] (7) Disinfection treatment: Use ozone to sterilize and disinfect the wastewater after flocculation treatment before discharge.

[0110] The bottom of the primary sedimentation tank is paved with filter filler with a thickness of 50 cm. The filter filler is natural river sand with a fineness of 1-3 mm.

[0111] Step (3) the anaerobic microbial agent comprises a functional microorganism and a carrier, wherein the functional microorganism is Pseudomonas mendocinae ( Pseudomonas mendocina The preparation method of the anaerobic microbial agent is as follows: activate Pseudomonas mendocinae and inoculate it into a fermentation medium for cultivation at a temperature of 28-30°C until the bacterial concentration is ≥3×10 8 / mL, terminate the culture, obtain the fermentation liquid, add the carrier into the bacterial liquid at a solid-liquid ratio of 10mL:100g, mix well and adsorb, then dry to obtain the anaerobic treatment microbial agent.

[0112] In this comparative example, except that only Pseudomonas mendocinae was used in the anaerobic microbial agent, the other raw materials and process parameters were the same as those in Example 1.

[0113] Comparative Example 2

[0114] In this comparative example, except that only Pseudomonas stutzeri was used in the anaerobic microbial agent, the other raw materials and process parameters were the same as those in Example 1. That is:

[0115] Step (3) the anaerobic microbial agent comprises a functional microorganism and a carrier, wherein the functional microorganism is Pseudomonas stutzeri ( Pseudomonas stutzeri) The preparation method of the anaerobic microbial agent is as follows: the activated Pseudomonas stutzeri is inoculated into a fermentation medium for cultivation at a temperature of 28-30°C until the bacterial concentration is ≥3×10 8 / mL, terminate the culture, obtain the fermentation liquid, add the carrier into the bacterial liquid at a solid-liquid ratio of 10mL:100g, mix well and adsorb, then dry to obtain the anaerobic treatment microbial agent.

[0116] Comparative Example 3

[0117] In this comparative example, except for changing the ratio of Pseudomonas mendocinae and Pseudomonas stutzeri in the anaerobic microbial agent, the other raw materials and process parameters are the same as those in Example 1. That is:

[0118] Step (3) the anaerobic microbial agent comprises a functional microorganism and a carrier, wherein the functional microorganism comprises Pseudomonas mendocinae ( Pseudomonas mendocina ) and Pseudomonas stutzeri ( Pseudomonas stutzeri ), the volume ratio of the two is 2:1; the preparation method of the anaerobic microbial agent is: activate Pseudomonas mendocinae and Pseudomonas stutzeri respectively and inoculate them into the fermentation medium for cultivation at a temperature of 28-30°C, and cultivate them to a bacterial concentration of ≥3×10 8 / mL, terminate the cultivation, and obtain the fermentation broth of the two bacteria. The fermentation broths of the two bacteria are mixed in a volume ratio of 2:1 to obtain a mixed bacterial solution. A carrier is added to the mixed bacterial solution in a solid-liquid ratio of 10mL:100g. After sufficient mixing and adsorption, the mixture is dried to obtain an anaerobic treatment microbial agent.

[0119] Comparative Example 4

[0120] In this comparative example, except for changing the ratio of Pseudomonas mendocinae and Pseudomonas stutzeri in the anaerobic microbial agent, the other raw materials and process parameters are the same as those in Example 1. That is:

[0121] Step (3) the anaerobic microbial agent comprises a functional microorganism and a carrier, wherein the functional microorganism comprises Pseudomonas mendocinae ( Pseudomonas mendocina ) and Pseudomonas stutzeri ( Pseudomonas stutzeri ), the volume ratio of the two is 1:2; the preparation method of the anaerobic microbial agent is: activate Pseudomonas mendocinae and Pseudomonas stutzeri respectively and inoculate them into the fermentation medium for cultivation at a temperature of 28-30°C, and cultivate them to a bacterial concentration of ≥3×10 8 / mL, terminate the cultivation, and obtain the fermentation broth of the two bacteria. The fermentation broths of the two bacteria are mixed in a volume ratio of 1:2 to obtain a mixed bacterial solution. A carrier is added to the mixed bacterial solution in a solid-liquid ratio of 10mL:100g. After sufficient mixing and adsorption, the mixture is dried to obtain an anaerobic treatment microbial agent.

[0122] Comparative Example 5

[0123] In this comparative example, except that only polyaluminium chloride is used for modification in the preparation of the modified flocculant, the other raw materials and process parameters are the same as those in Example 1. That is:

[0124] The preparation method of the modified flocculant in step (5) is:

[0125] (1) Weighing 10 g of zeolite, placing it in 100 mL of a 30 g / L sodium chloride solution, shaking it at 45-50° C. and an oscillation frequency of 150 r / min for 30 min, washing the zeolite to neutrality after shaking, drying it at 100-105° C., placing it in a desiccator to cool to room temperature, and then setting it aside;

[0126] (2) Take 10 g of the zeolite obtained in step (1) and place it in a container, add 40% of the mass of zeolite polyaluminium chloride, add 100 mL of deionized water and stir to mix evenly, let it stand for 30 min, put it in a constant temperature drying oven, dry it at 55-65°C to constant weight, take it out and let it stand to cool, and obtain a modified flocculant.

[0127] Comparative Example 6

[0128] In this comparative example, except that only polyaluminium ferric silicate is used for modification in the preparation of the modified flocculant, the other raw materials and process parameters are the same as those in Example 1. That is:

[0129] The preparation method of the modified flocculant in step (5) is:

[0130] (1) Weighing 10 g of zeolite, placing it in 100 mL of a 30 g / L sodium chloride solution, shaking it at 45-50° C. and an oscillation frequency of 150 r / min for 30 min, washing the zeolite to neutrality after shaking, drying it at 100-105° C., placing it in a desiccator to cool to room temperature, and then setting it aside;

[0131] (2) Take 10 g of the zeolite obtained in step (1) and place it in a container, add 40% of the mass of the zeolite polyaluminium ferrosilicate, add 100 mL of deionized water and stir to mix evenly, let it stand for 30 min, put it in a constant temperature drying oven, dry it at 55-65°C to constant weight, take it out and let it stand to cool, and obtain a modified flocculant.

[0132] Performance Testing

[0133] Strain degradation ability verification:

[0134] Fermentation (mixed) bacterial liquids were prepared according to the methods of the anaerobic microbial agents in Examples 1-3 and Comparative Examples 1-4, respectively, to verify the removal effect of pollutants in sewage by fermentation liquids composed of different strains. Simulated sewage was set, and the sewage composition was: the original COD concentration and ammonia nitrogen concentration were 3000 mg / L and 300 mg / L, respectively.

[0135] The experimental method is:

[0136] Measure 150mL of simulated sewage sample into a 250mL Erlenmeyer flask, add 5mL of the fermentation liquid to be tested, mix thoroughly, seal with plastic film to create an anaerobic environment, and at room temperature for 12 hours, determine the COD and ammonia nitrogen contents in the sewage and calculate the removal rates of COD and ammonia nitrogen. Repeat 5 times for each treatment group and take the average of the results.

[0137] The COD was determined by potassium dichromate method, and the ammonia nitrogen was determined by Nessler's reagent colorimetric method. The calculation formulas for COD and ammonia nitrogen removal rates are:

[0138] COD removal rate = (original COD concentration - COD concentration after treatment) / original COD concentration × 100%;

[0139] Ammonia nitrogen removal rate = (original ammonia nitrogen concentration - ammonia nitrogen concentration after treatment / original ammonia nitrogen concentration) × 100%;

[0140] The results are shown in Table 1:

[0141] Table 1 Treatment effects of fermentation broths composed of different strains

[0142]

[0143] From the data in Table 1, we can see that the mixed bacterial liquid prepared by mixing the two microbial strains in equal proportions in the embodiment of the present invention has good COD and ammonia nitrogen removal capabilities, while the fermentation liquid with changed strain composition breaks the synergistic balance between the two, and the COD and ammonia nitrogen removal capabilities are significantly weakened.

[0144] Flocculant flocculation ability verification

[0145] Flocculant to be tested:

[0146] S1: modified flocculant obtained in Example 1;

[0147] S2-S3: modified flocculants obtained in Comparative Examples 5-6;

[0148] S4: Commonly used flocculant polyaluminium chloride;

[0149] S5: Commonly used flocculant polyaluminium ferric silicate;

[0150] Weigh 0.25 g of kaolin into a 100 mL beaker, add 50 mL of distilled water and 5 mL of 10 g / L CaCl 2 After adjusting the pH value to 6-7, add the flocculant to be tested according to the amount of 20g flocculant / t of the sewage to be tested, stir thoroughly, let it stand for 20 minutes to separate the layers, draw the liquid about 1cm below the liquid surface, and measure the absorbance (OD) at 550nm. 550), repeat the experiment 3 times, and take the average value. Then, calculate the flocculation rate by the formula. At the same time, set a blank control, that is, do not add any flocculant, the formula is as follows: ×100%, where F is the flocculation rate; M is the OD of the blank control group. 550 ; N is the OD of the experimental group 550 The experimental results are as follows Figure 1 As shown, the flocculation effect of the flocculant obtained in the embodiment of the present invention is higher than that of the comparative example and the conventional flocculant experimental group. From the microstructure schematic diagrams of the flocculants in the embodiment and the comparative example, we can also see that the surface of the modified flocculant of the present invention presents a lamellar villi porous structure, while in comparative examples 5-6 lacking polyaluminum chloride or polyaluminum ferric silicate, the synergistic modification effect of the two disappears, the surface modification effect is weakened, the villi structure is reduced, and the dense villi structure on the surface of the flocculant is also the key to the good flocculation and adsorption effect of the modified flocculant of the present invention.

[0151] Actual aquaculture wastewater treatment:

[0152] Sewage source: a large-scale dairy farm in Shandong Province;

[0153] Aquaculture wastewater was treated according to the methods of Examples 1-3 and Comparative Examples 1-6 of the present invention.

[0154] The test method is as follows: COD is determined by potassium dichromate method GB11914-89; ammonia nitrogen (NH 4+ -N) was determined by Nessler's reagent colorimetry; TP ammonium molybdate spectrophotometry; fecal coliform bacteria was determined by paper strip rapid method HJ 755-2015; SS suspended solids were determined by national standard GB11901-89 "Determination of suspended solids in water quality - Gravimetric method"; heavy metal elements: Cu was determined by sodium diethyldithiocarbamate spectrophotometry; Zn was determined by dithizone spectrophotometry; Mn was determined by flame atomic absorption spectrophotometry; Cd was determined by dithizone spectrophotometry; Cr 6+ The diphenylcarbazide spectrophotometric method was used; As was determined by the arsenic spot method. The specific test results are shown in Table 2-3:

[0155] Table 2 Aquaculture wastewater purification results

[0156]

[0157] Table 3 Aquaculture wastewater purification results

[0158]

[0159] From the data in Table 2-3, we can see that Examples 1-3 of the present invention show good purification treatment effects on aquaculture wastewater, while the purification effects of Comparative Examples 1-4 and Comparative Examples 5-6, which have changed the composition of anaerobic fermentation strains, are significantly weakened. This is because the synergistic balance between Pseudomonas mendocinae and Pseudomonas stutzeri is broken, and the surface morphology modification effect of the zeolite modified with single polyaluminum chloride or polyaluminum ferrosilicate is reduced, and the flocculation effect is weakened, so the sewage treatment effect of the comparative example is significantly reduced.

[0160] It should be noted that the above embodiments are only partial embodiments of the preferred methods of implementing the present invention, rather than all embodiments. Obviously, based on the above embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

Claims

1. A method for purifying mixed sewage from animal husbandry, characterized in that: The processing steps include: (1) Solid-liquid separation and sedimentation treatment: The wastewater to be treated is sent to a solid-liquid separator for solid-liquid separation. After solid-liquid separation, the wastewater is introduced into a primary sedimentation tank and allowed to stand for 1-2 hours for preliminary adsorption and sedimentation filtration; (2) Flotation treatment: After primary sedimentation and filtration, the sewage enters the flotation treatment tank, where a large number of tiny bubbles are generated through the flotation principle. The tiny bubbles absorb the fine particles in the sewage and remove the micro-particles in the aquaculture sewage; (3) Anaerobic treatment: The wastewater treated with flotation is introduced into the anaerobic tank, the pH of the system is adjusted to 6.5-7.5, and anaerobic microbial agents of 5% of the wastewater mass are added for anaerobic treatment. The dissolved oxygen content in the anaerobic treatment tank is controlled below 0.5 mg / L. The anaerobic treatment time is 8-10 hours. After the treatment, the wastewater is allowed to settle for 1-2 hours. (4) Aerobic treatment: The anaerobic treated sewage is introduced into the aerobic tank, the pH of the system is adjusted to 6.5-7.5, and aerobic microbial agents of 5% of the sewage mass are added for aerobic fermentation. The aerobic fermentation time is 3-5 hours, and the treatment is completed and allowed to settle for 1-2 hours; (5) Flocculation treatment: The aerobic treated sewage is introduced into the flocculation tank, and a modified flocculant is added at a rate of 10-20 g / t. The flocculation and adsorption treatment time is 1-2 h; (6) Separation treatment: The wastewater after flocculation treatment is separated into solid and liquid by a centrifuge to remove solid matter, and the liquid is discharged and collected in a disinfection tank; (7) Disinfection treatment: Use ozone to sterilize and disinfect the wastewater after flocculation treatment before discharge; Step (3) the anaerobic microbial agent comprises a functional microorganism and a carrier, wherein the functional microorganism comprises Pseudomonas mendocinae ( Pseudomonas mendocina ) and Pseudomonas stutzeri ( Pseudomonas stutzeri ), the volume ratio of the two is 1:1; the preparation method of the anaerobic microbial agent is: activate Pseudomonas mendocinae and Pseudomonas stutzeri respectively and inoculate them into the fermentation medium for cultivation at a temperature of 28-30°C, and cultivate them to a bacterial concentration of ≥3×10 8 / mL, terminate the cultivation, and obtain the fermentation broth of the two bacteria, mix the fermentation broths of the two bacteria in a volume ratio of 1:1 to obtain a mixed bacterial solution, add a carrier to the mixed bacterial solution in a solid-liquid ratio of 10mL:100g, fully mix and adsorb, and then dry to obtain an anaerobic treatment microbial agent.

2. The method for purifying mixed wastewater from livestock breeding according to claim 1, characterized in that: The bottom of the primary sedimentation tank is paved with filter filler with a thickness of 50-70 cm. The filter filler is natural river sand with a fineness of 1-3 mm.

3. The method for purifying mixed wastewater from livestock breeding according to claim 1, characterized in that: The strain number of the Pseudomonas mendocinae is CGMCC No. 1.8049, which was purchased from the General Microbiology Center of China National Microbiological Culture Collection (CGMCC); the strain number of the Pseudomonas stutzeri is CGMCC No. 1.15316, which was purchased from the General Microbiology Center of China National Microbiological Culture Collection (CGMCC).

4. The method for purifying mixed wastewater from livestock breeding according to claim 1, characterized in that: The carrier comprises diatomaceous earth, sodium alginate, chitosan and sucrose in a mass ratio of (50-100):(1-5):(0.5-1.5):(1-5).

5. The method for purifying mixed wastewater from livestock breeding according to claim 1, characterized in that: The aerobic microbial agent in step (4) comprises Bacillus mucilaginosus, Bacillus megaterium and Bacillus amyloliquefaciens, and the mass ratio of the three is 1:1:

1.

6. The method for purifying mixed wastewater from animal husbandry according to claim 1, characterized in that: During the aerobic treatment in step (4), aeration is performed at an air-water ratio of 15:1, once per hour, and each aeration time is 10 minutes.

7. The method for purifying mixed wastewater from livestock breeding according to claim 1, characterized in that: The preparation method of the modified flocculant in step (5) is: (1) Weighing 10 g of zeolite, placing it in 100 mL of a sodium chloride solution with a concentration of 30-60 g / L, shaking it at 45-50° C. and an oscillation frequency of 150-200 r / min for 30-60 min, washing the zeolite to neutrality after shaking, drying it at 100-105° C., placing it in a desiccator to cool to room temperature and then setting it aside; (2) Take 10 g of the zeolite obtained in step (1) and place it in a container, add 20% of the mass of zeolite polyaluminium chloride and 20% of the mass of zeolite polyaluminium ferrosilicate, add 100 mL of deionized water and stir to mix evenly, let it stand for 30 min, put it in a constant temperature drying oven, dry it at 55-65°C to constant weight, take it out and let it stand to cool, and obtain a modified flocculant.

8. The method for purifying mixed wastewater from livestock breeding according to claim 1, characterized in that: The ozone treatment time in step (7) is 30-35 minutes, and the ozone dosage is 5-10 mg / L.

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