A solid bacterial block for treating acid mine wastewater and its preparation method and application

Abstract

The present invention discloses a solid bacterial block for treating acid mine wastewater, and a preparation method and application thereof, and relates to the technical field of acid wastewater treatment. The solid bacterial block is composed of 100 to 150 parts of microbial agents, 50 to 100 parts of nutritional components, 200 to 300 parts of carriers, and 50 to 100 parts of binders by mass. The above microbial agents, nutritional components, carriers and binders are mixed in proportion and compressed into blocks to form solid bacterial blocks. The solid bacterial block provided by the present invention has high activity, simple use, long and stable continuous cycle, can be directly put into the acid water reactor for use after removing the film, can efficiently remove heavy metals in acid mine wastewater, and better solves the problems of poor acid water impact resistance, slow environmental adaptation, limited treatment efficiency, large packaging volume, and high transportation cost of traditional liquid bacterial agents.

Description

Technical Field

[0001] The invention relates to the technical field of sewage treatment, and in particular to a solid bacterial block for treating acid mine wastewater, and a preparation method and application thereof. Background Art

[0002] Heavy metal pollution has become a major environmental problem facing my country. Mining activities are the main source of heavy metal pollution, which mainly releases pollution to the surrounding environment in the form of acid mine drainage (AMD), seriously affecting farmland soil quality, drinking water safety and residents' health.

[0003] Acid mine wastewater usually has a low pH value, even below 2.0, and a high content of heavy metal ions, making it one of the main sources of mine pollution. At present, the most commonly used treatment technology is the neutralization method, but it has problems such as severe scaling, huge sludge production, and high treatment costs, which makes it difficult for mining companies to apply and difficult to bear in the long run. The microbial method has the advantages of low investment cost, environmental friendliness, and small amount of sludge, and is currently the most promising treatment technology. The microbial method mainly uses sulfate-reducing bacteria to treat acidic wastewater through biological sulfidation. This technology has the following disadvantages. On the one hand, the heavy metal ions and extreme acidity in acid mine wastewater will limit the growth and reproduction of microorganisms. If the sulfate-reducing bacteria solution is directly added to the acid mine wastewater, it will affect the impact resistance of the sulfate-reducing bacteria, reduce the activity of the sulfate-reducing bacteria, and lead to low acid water treatment efficiency; on the other hand, traditional microbial agents are mainly liquid products, with high packaging costs and inconvenient transportation, which limit the practical application of microbial treatment methods. Summary of the invention

[0004] In view of the above problems, the present invention proposes a solid bacterial block for treating acid mine wastewater, and a preparation method and application thereof, which has high treatment efficiency and can effectively remove heavy metals in acid mine wastewater.

[0005] One of the purposes of the present invention is to provide a solid bacterial block for treating acid mine wastewater.

[0006] The technical solution adopted by the present invention is as follows: a solid bacterial block for treating acid mine wastewater is composed of 100-150 parts of microbial agents, 50-100 parts of nutrient components, 200-300 parts of carriers, and 50-100 parts of binders in terms of mass.

[0007] The microbial agent is a preparation containing acidophilic sulfate-reducing bacteria.

[0008] Acidophilic sulfate-reducing bacteria can tolerate acidity down to pH 3.5.

[0009] The nutritional components include one or a combination of two or more of sugar residue, wheat bran, rice husk, livestock and poultry excrement, etc. In one embodiment, the nutritional components are sugar residue, wheat bran, rice husk and livestock and poultry excrement, wherein the mass ratio of sugar residue: wheat bran: rice husk: livestock and poultry excrement is 20-25:10-15:5-10:50-60.

[0010] The carrier includes one or a combination of two or more of grass fiber, wood fiber, bagasse, and corn stalks. In one embodiment, the carrier is grass fiber, wood fiber, bagasse, and corn stalks, wherein the mass ratio of grass fiber: wood fiber: bagasse: corn stalks is 40-50: 30-40: 5-10: 10-20.

[0011] The adhesive is a special adhesive for spraying.

[0012] The second object of the present invention is to provide a method for preparing the solid mushroom block.

[0013] The technical solution adopted by the present invention is as follows: A method for preparing a solid bacterial block for treating acid mine wastewater comprises the following steps:

[0014] (1) Preparation of microbial inoculants: enrich and culture acidophilic sulfate-reducing bacteria until the effective viable count is not less than 10 7 cfu / g, then centrifuge and discard the supernatant to obtain a bacterial sludge mixture 1; then wash the bacterial sludge mixture 1 with 0.01M PBS buffer solution, centrifuge and discard the supernatant to obtain a bacterial sludge mixture 2; then mix the bacterial sludge mixture 2 with the nutrient solution in a ratio of 1:10~1:20 to obtain a microbial agent for use.

[0015] (2) Preparation of nutritional components: Prepare nutritional components by taking one or more of sugar residue, wheat bran, rice husk, livestock and poultry manure, etc. for later use.

[0016] (3) Prepare the carrier: Prepare the carrier by taking one or more of grass fiber, wood fiber, bagasse, and corn stalk for use.

[0017] (4) Weigh 50-100 parts of nutrient components, 200-300 parts of carriers, 50-100 parts of binders, etc. by weight as the base material, mix and stir evenly, and weigh 100-150 parts of microbial agents for later use.

[0018] (5) The base material weighed in step (4) is mixed and stirred evenly, and then the microbial agent weighed in step (4) is added according to the mass ratio, and compressed and packaged to form a cylindrical bacterial block.

[0019] In step (1), the nutrient solution is used to maintain the carbon source, salts and thickener required for the growth of the bacterial agent, and the composition includes 2g / L yeast extract, 1g / L glycerol, (NH4 ) 2 SO 4 1.5 g / L, sodium alginate 2 g / L, and adjusted to the suitable growth pH of 4 - 5 for acidophilic sulfate-reducing bacteria.

[0020] In step (1), the acid resistance of the acidophilic sulfate-reducing bacteria can be as low as pH 3.5.

[0021] In step (1), the centrifugation conditions are: 8000 - 10000 rpm, 5 - 10 min.

[0022] In step (2), the sugar residue, wheat bran, rice husk, and livestock and poultry manure are formulated into the nutrient components according to the mass ratio of 20 - 25:10 - 15:5 - 10:50 - 60.

[0023] In step (3), the straw fiber, wood fiber, bagasse, and corn straw are formulated into the carrier according to the mass ratio of 40 - 50:30 - 40:5 - 10:10 - 20.

[0024] In step (5), the cylindrical bacterial blocks are divided into three specifications: large, medium, and small. The size of the large-sized bacterial block is usually 40 cm in diameter × 50 cm in height, and the weight is 28 - 30 kg; the size of the medium-sized bacterial block is usually 30 cm in diameter × 40 cm in height, and the weight is 12 - 13 kg; the size of the small-sized bacterial block is usually 20 cm in diameter × 30 cm in height, and the weight is 4.0 - 4.5 kg. The specific specifications are determined according to the on-site use situation.

[0025] The third object of the present invention is to provide the application of the above solid bacterial block.

[0026] The technical solution adopted by the present invention is as follows: the application of the solid bacterial block for treating mine acidic wastewater. The solid bacterial block is transported to the mine, and after removing the film, it is added to the mine acidic wastewater sump or the acidic wastewater treatment pool. The dosage of the bacterial block is 10 - 20 kg / m 3 , to ensure the activity of the bacterial agent, it is put into use within 1 month after the preparation of the bacterial block, and the treatment time is usually 10 - 15 d.

[0027] The bacterial blocks are arranged side by side in a single layer or stacked in a multi-layer "pin" shape and soaked in the mine acidic wastewater. This can not only ensure the stability and firmness of the stacking of the bacterial blocks, but also utilize the gaps formed by the carriers such as straw fiber, wood fiber, bagasse, and corn straw to provide a buffer space for the bacterial agent, improve the impact resistance of the bacterial agent in acidic water, and help the bacterial agent grow and reproduce rapidly in the wastewater.

[0028] The carriers of the bacterial blocks prepared by the present invention are all composed of easily degradable agricultural waste and can be used as the microbial carbon source. Therefore, when using the bacterial blocks prepared by the present invention to treat acidic wastewater, the amount of produced residue is less, and there is no pressure for later residue removal. The present invention can realize the harmless treatment of mine acidic wastewater.

[0029] (1) The solid bacterial block for treating acid mine wastewater provided by the present invention contains a dry powder bacterial agent, which has a higher concentration and stronger activity than the traditional liquid bacterial agent, and has a higher efficiency in removing heavy metals in acid mine wastewater. The pH can be raised from acidic to neutral, and the reduction of major heavy metals such as Pb, Zn, Cu, and Cd exceeds 90%.

[0030] (2) Compared with traditional liquid bacterial agents, the solid bacterial blocks provided by the present invention are smaller in size, more regular in shape, and easier to transport, thus greatly reducing storage and transportation costs.

[0031] (3) The solid mushroom block provided by the present invention has no odor, is easy to use and operate, does not require the addition of an additional carbon source, and has no slag cleaning pressure and secondary pollution, thereby greatly reducing the cost of treating acid mine wastewater. DETAILED DESCRIPTION

[0032] Embodiment 1

[0033] The implementation site is located in a polymetallic mine in Shaoguan, Guangdong. A concrete pool was built in a dump area as a reaction pool. The reaction pool is 5.4m long × 3.6m wide × 1.8m deep, with a bottom plate and pool wall thickness of 20cm and an effective capacity of 24m 3 The acid water comes from the drainage of the mine, is dark red, and has a pH as low as 3.1. The technology of the present invention is used to treat the wastewater from the mine in the treatment pool. The specific steps are as follows:

[0034] (1) Preparation of microbial agents: enrichment and culture of acidophilic sulfate-reducing bacteria. The acid resistance of acidophilic sulfate-reducing bacteria can be as low as pH 3.5. The effective viable count was tested to reach 3.5×10 7 cfu / g, centrifuge the bacterial solution at 10000rpm for 5min, discard the supernatant, and obtain bacterial sludge mixture 1; then wash the bacterial sludge mixture 1 with 0.01M PBS buffer solution, centrifuge it at 10000rpm for 5min, and discard the supernatant to obtain bacterial sludge mixture 2; then mix the bacterial sludge mixture 2 with the nutrient solution at a ratio of 1:20 to obtain a microbial agent for standby use. The nutrient solution ingredients are: yeast extract 2g / L, glycerol 1g / L, (NH 4 ) 2 SO 4 1.5 g / L, sodium alginate 2 g / L, pH 5.

[0035] (2) Prepare the nutritional components with sugar residue, wheat bran, rice husk and livestock and poultry manure in a mass ratio of 25:10:5:60 for later use.

[0036] (3) Prepare a carrier using grass fiber, wood fiber, bagasse and corn straw in a mass ratio of 45:40:5:10 for later use.

[0037] (4) Weigh 100 parts of nutrient components, 300 parts of carrier, 100 parts of binder, etc. by weight respectively as the base material, and mix and stir them evenly. Additionally, weigh 150 parts of microbial inoculum for standby.

[0038] (5) Mix and stir the base material weighed in step (4) evenly, add it to the bottom of the conveyor belt of the silage packing and wrapping machine, and add the microbial inoculum weighed in step (4) to the top of the conveyor belt according to the mass ratio. The base material and the microbial inoculum enter the packing machine for compression and packing to form cylindrical bacterial blocks, and are hermetically packaged by the wrapping machine to form individual bacterial blocks of small size for standby.

[0039] Transport the prepared bacterial blocks to the test site, remove the film, and throw them into the acidic water pit by manual delivery. The dosage of the bacterial blocks is 15 kg / m 3 , and distribute them in areas, stacking them in a four-layer "pin" shape, with a total of 80 small-sized bacterial blocks being put in.

[0040] After 10 days, take samples of the wastewater in the treatment pond for testing. According to the test results, the water quality of the mine wastewater treated by the technology of the present invention has been significantly improved. The pH has risen from 3.1 to neutral, and the reduction amounts of main heavy metals such as Pb, Zn, Cu, Cd, and As all exceed 90%. Table 1 shows the water quality test results of the reaction pond after 10 days of treatment.

[0041] Table 1 Comparison of water quality of acidic wastewater from a certain mine in Shaoguan before and after treatment (unit: mg / L)

[0042]

[0043] Example 2

[0044] The implementation site is located at a heavy metal mine in Shangrao, Jiangxi. Select an acidic water pit below a certain waste dump as the test area. This acidic water pit is formed by the surface seepage water of the waste dump. The surface area of this water pit is about 200 m 2 , and the average water depth is about 2.5 m. After testing, the average pH of the water quality of the water pit is 3.7, and the contents of lead, zinc, copper, and cadmium are 0.39 mg / L, 80 mg / L, 41.4 mg / L, and 0.11 mg / L respectively. Use the technology of the present invention to treat the wastewater in the acidic water pit. The specific steps are as follows:

[0045] (1) Prepare microbial inoculum: Enrich and culture acidophilic sulfate-reducing bacteria. After testing, the effective viable bacteria count reaches 1.2×10 7cfu / g. The bacterial liquid was centrifuged at 8000 rpm for 10 min, and the supernatant was discarded to obtain bacterial sludge mixture 1. Then, bacterial sludge mixture 1 was washed with 0.01 M PBS buffer solution, centrifuged at 8000 rpm for 10 min, and the supernatant was removed to obtain bacterial sludge mixture 2. Then, bacterial sludge mixture 2 was mixed with a nutrient solution (2 g / L yeast extract, 1 g / L glycerol, (NH 4 ) 2 SO 4 1.5 g / L, 2 g / L sodium alginate, pH 4) in a ratio of 1:10 to obtain a microbial inoculant for standby.

[0046] (2) Sugar residues, wheat bran, rice husks and livestock manure were prepared as nutrient components for standby according to a mass ratio of 20:15:10:55.

[0047] (3) Straw fiber, wood fiber, bagasse and corn straw were prepared as carriers for standby according to a mass ratio of 40:30:10:20.

[0048] (4) 50 parts of nutrient components, 200 parts of carrier, 50 parts of binder, etc. were weighed by weight and used as the base material for mixing and stirring evenly. In addition, 100 parts of microbial concentrated bacterial slurry were weighed for standby.

[0049] (5) The base material weighed in step (4) was mixed and stirred evenly, added to the bottom of the conveyor belt of the silage packing and wrapping machine, and the concentrated bacterial slurry weighed in step (4) was added to the top of the conveyor belt according to the mass ratio. The base material and the concentrated bacterial slurry entered the packing machine for compression and packing to form cylindrical bacterial blocks, and were sealed and packaged by the wrapping machine to form separate bacterial block packages in three specifications of large, medium and small sizes for standby.

[0050] The prepared bacterial blocks were transported to the test site. After removing the film, they were put into the acidic water pit manually and mechanically. The dosage of the bacterial blocks was 10 kg / m 3 , distributed by area, and stacked in a double-layer "pin" shape. A total of 100 large-sized bacterial blocks, 150 medium-sized bacterial blocks and 100 small-sized bacterial blocks were put in.

[0051] After 15 days, the wastewater in the treatment pool was sampled and tested. According to the test results, the water quality of the mine wastewater treated by the present invention was significantly improved. The pH increased from 3.7 to neutral, and the reduction amounts of main heavy metals such as Pb, Zn, Cu, Cd, etc. all exceeded 95%. Table 2 shows the water quality test results of the acidic water pit after 15 days of treatment.

[0052] Table 2 Comparison of water quality of acidic wastewater from a mine in Shangrao before and after treatment (unit: mg / L)

[0053]

[0054] Note: ND means not detected, the result is below the detection limit.

[0055] The above are only preferred embodiments of the present invention, and the patent protection scope of the present invention is not limited thereto. Any equivalent structural transformations made using the contents of the present invention's specification and drawings, directly or indirectly used in other related technical fields, are also included in the protection scope of the present invention.

Claims

1. A solid bacterial block for treating acid mine wastewater, characterized in that: The composition comprises 100-150 parts of microbial agents, 50-100 parts of nutritional components, 200-300 parts of carriers, and 50-100 parts of binders in proportion by mass; the nutritional components are sugar residue, wheat bran, rice husks, and livestock and poultry excrement, wherein the mass ratio of sugar residue: wheat bran: rice husks: livestock and poultry excrement is 20-25:10-15:5-10:50-60; the carrier is grass fiber, wood fiber, bagasse, and corn stalks, wherein the mass ratio of grass fiber: wood fiber: bagasse: corn stalks is 40-50:30-40:5-10:10-20; The preparation method is as follows: (1) Preparation of microbial agents: enrich and culture acidophilic sulfate-reducing bacteria until the effective viable count is not less than 10 7 cfu / g, then centrifuged and discarded the supernatant to obtain a bacterial sludge mixture 1; then the bacterial sludge mixture 1 was washed with a 0.01M PBS buffer solution, and the supernatant was removed after centrifugation to obtain a bacterial sludge mixture 2; then the bacterial sludge mixture 2 was mixed with a nutrient solution at a ratio of 1:10-1:20 to obtain a microbial agent; (2) Preparation of nutritional components: The nutritional components are prepared according to the mass ratio of sugar residue: wheat bran: rice husk: livestock and poultry manure of 20-25:10-15:5-10:50-60; (3) Preparation of carrier: Prepare the carrier according to the mass ratio of grass fiber: wood fiber: bagasse: corn straw of 40~50:30~40:5~10:10~20; (4) Weigh 50-100 parts of nutrient components, 200-300 parts of carriers, and 50-100 parts of binders as base materials, and weigh 100-150 parts of microbial agents; (5) The base material weighed in step (4) is mixed and stirred evenly, and then the microbial agent weighed in step (4) is added according to the mass ratio, and compressed and packaged to form a cylindrical bacterial block.

2. A method for preparing a solid bacterial block for treating acid mine wastewater, characterized in that: The steps include: (1) Preparation of microbial agents: enrich and culture acidophilic sulfate-reducing bacteria until the effective viable count is not less than 10 7 cfu / g, then centrifuged and discarded the supernatant to obtain a bacterial sludge mixture 1; then the bacterial sludge mixture 1 was washed with a 0.01M PBS buffer solution, and the supernatant was removed after centrifugation to obtain a bacterial sludge mixture 2; then the bacterial sludge mixture 2 was mixed with a nutrient solution at a ratio of 1:10-1:20 to obtain a microbial agent; (2) Preparation of nutritional components: preparing the nutritional component straw according to the mass ratio of sugar residue: wheat bran: rice husk: livestock and poultry manure of 20~25:10~15:5~10:50~60; (3) Preparation of carrier: Prepare the carrier according to the mass ratio of grass fiber: wood fiber: bagasse: corn straw of 40~50:30~40:5~10:10~20; (4) Weigh 50-100 parts of nutrient components, 200-300 parts of carriers, and 50-100 parts of binders as base materials, and weigh 100-150 parts of microbial agents; (5) The base material weighed in step (4) is mixed and stirred evenly, and then the microbial agent weighed in step (4) is added according to the mass ratio, and compressed and packaged to form a cylindrical bacterial block.

3. The method for preparing the solid bacterial block for treating acid mine wastewater according to claim 2, characterized in that: In step (1), the composition of the nutrient solution includes 2 g / L yeast extract, 1 g / L glycerol, 1.5 g / L (NH4)2SO4, and 2 g / L sodium alginate, and is adjusted to a pH of 4-5 suitable for the growth of acidophilic sulfate-reducing bacteria.

4. The method for preparing a solid bacterial block for treating acid mine wastewater according to claim 2, characterized in that: In step (1), the acid resistance of the acidophilic sulfate-reducing bacteria is as low as pH 3.5; the centrifugation conditions are: 8000-10000 rpm, 5-10 min.

5. The method for preparing the solid bacterial block for treating acid mine wastewater according to claim 2, characterized in that: In step (5), the cylindrical mushroom blocks are divided into three sizes: large, medium and small. The large size has a diameter of 40 cm and a height of 50 cm, and a weight of 28 to 30 kg; the medium size has a diameter of 30 cm and a height of 40 cm, and a weight of 12 to 13 kg; the small size has a diameter of 20 cm and a height of 30 cm, and a weight of 4.0 to 4.5 kg.

6. The use of the solid bacterial block for treating acid mine wastewater according to claim 1, characterized in that: The solid bacterial block is transported to the mine, and after the membrane is removed, it is added to the mine acid wastewater accumulation pit or acid wastewater treatment pool. The solid bacterial block is added in an amount of 10-20 kg / m 3 The processing time is 10~15d.

7. The use of solid bacterial blocks for treating acid mine wastewater according to claim 6, characterized in that: The solid bacterial blocks shall be put into use within 1 month after being prepared; the solid bacterial blocks shall be immersed in the acidic mine wastewater in a single-layer side-by-side arrangement or in a multi-layer "pin" shape stacking.

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