Method for preparing sulfate reducing bacteria (SRB) microbial inoculum by using active carbon (HC)

Abstract

The invention discloses a method for preparing a sulfate reducing bacteria (SRB) microbial inoculum by using activated carbon (HC). According to the invention, the HC is used as a cheap fixing carrier for fixing the SRB, so that the rate and the acid resistance of the SRB for treating the acid mine wastewater (AMD) can be effectively improved. The method provided by the invention has the advantages of high treatment efficiency and low cost, can relieve acid stress when the AMD is treated by SRB, and is an immobilization method which is high in efficiency, easy to operate and free of pollution.

Description

Technical Field

[0001] The invention belongs to the field of wastewater treatment and microbial immobilization, and relates to a method for preparing an SRB bacterial agent, in particular to a method for preparing an SRB bacterial agent by using HC as a carrier of SRB. Background Art

[0002] With the development of human society, the demand for mineral resources is increasing day by day. Various pollutants will be generated in the process of mineral resource development and utilization. Sulfur-containing minerals are exposed to the air, and after long-term contact with water, oxygen and microorganisms, chemical oxidation and biological oxidation will occur. When they come into contact with the surface water and groundwater of the mine, acid mine drainage (AMD) containing a large amount of sulfate and heavy metal ions will be formed. Untreated AMD entering the water body will cause water acidification, destroy biodiversity and water self-purification capacity; the soil structure flowing through AMD will be destroyed, causing soil acidification, vegetation death and crop yield decline; heavy metals in AMD enter the human body through the food chain, seriously damaging human health.

[0003] At present, the treatment technologies of AMD mainly include source control technology and end-of-pipe treatment technology. Source control technology mainly affects the conditions for the formation of AMD in the early stage of its generation, slows down its reaction process, and thus achieves the purpose of inhibiting the generation of acidic wastewater. Source control technology is considered to be an ideal solution because it can permanently prevent the formation of AMD, reduce the management costs of AMD in the later stage, and reduce the treatment cost. End-of-pipe treatment technology mainly uses physical, chemical and biological means to reduce the concentration of pollutants in water bodies and meet the discharge standards. End-of-pipe treatment technology includes active treatment and passive treatment. Generally speaking, the cost of passive treatment is lower than that of active treatment measures. Therefore, passive treatment is also a hot spot in the current research on acidic wastewater treatment. Among them, the method of using SRB to treat AMD is a green remediation technology with low cost, clean and environmental protection, no secondary pollution and resource recovery, which has been widely studied.

[0004] The growth of SRB is affected by temperature, pH, COD, heavy metals and SO4 2- The pH of AMD is generally less than 5, and SRB can only grow in a neutral environment, which greatly limits the application of SRB in the treatment of AMD. Summary of the invention

[0005] The purpose of the present invention is to overcome the deficiencies in the prior art, provide a method for preparing a SRB bacterial agent that is easy to operate, and improve the rate and acid resistance of SRB in treating AMD.

[0006] To achieve the above object, the technical solution of the present invention is as follows:

[0007] A method for preparing SRB bacterial agent using HC, characterized by comprising the following steps:

[0008] 1. Place Postgate C medium dissolved in distilled water in a sealed anaerobic bottle, adjust the pH to 7.0-7.2, blow nitrogen for 15 minutes, and sterilize at 121°C for 20 minutes;

[0009] 2. After the culture medium has cooled to room temperature, add HC and 20% SRB bacterial solution to the culture medium and place it in a 35°C constant temperature incubator for static culture;

[0010] 3. After culturing for 3 days, the mixture was centrifuged at 8000 r / min for 5 min; the solid after centrifugation was washed three times with sterile saline, which was the biochar fixation bacteria HC-SRB;

[0011] 4. Mix HC-SRB and fresh Postgate C medium and store in a 4°C refrigerator.

[0012] The components of the Postgate C culture medium in step 1 are: KH2PO4 (0.5g / L), MgSO4·7H2O (1.5g / L), Na2SO4 (1.2g / n), CaCl2 (0.06g / L), Fe(NH4)2·(SO4)2·6H2O (0.3g / L), NaCl (1.0g / L), NH4Cl (1.0g / L), sodium lactate (3.5ml / L), yeast powder (1.0g / L), L-cysteine ​​(0.3g / L), and ascorbic acid (0.3g / L).

[0013] The particle size of HC in step 2 is 200 mesh; the amount of HC added is 0.6 g / L.

[0014] In step 2, HC is used to fix SRB by adding HC to Postgate C medium at the same time.

[0015] In the step 3, the time for HC to fix SRB is 3 days, the centrifugal speed for obtaining HC-SRB is 8000 r / min, and the centrifugal time is 5 minutes.

[0016] The HC-SRB in step 4 was stored in a 4°C refrigerator.

[0017] The beneficial effects of the present invention are:

[0018] (1) The HC used in the present invention has a porous structure and a large specific surface area, has excellent adsorption and precipitation properties, and can efficiently fix SRB;

[0019] (2) The present invention can not only effectively increase the rate of SRB treating AMD, but also improve the acid resistance of SRB. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 : pH of AMD with different pH after being treated with HC-SRB and SRB bacterial solution for 72 h;

[0021] Figure 2 : Sulfate content of AMD with different pH values ​​after being treated with HC-SRB and SRB bacterial solutions for 72 h. DETAILED DESCRIPTION

[0022] The present invention will be further described below in conjunction with embodiments:

[0023] A method for preparing SRB bacterial agent using HC, the steps of which are:

[0024] (1) Place Postgate C medium dissolved in distilled water in a sealed anaerobic bottle, adjust the pH to 7.0-7.2, blow nitrogen for 15 min, and sterilize at 121°C for 20 min;

[0025] (2) After the culture medium has cooled to room temperature, HC and 20% SRB bacterial solution are added to the culture medium and placed in a 35°C constant temperature incubator for static culture;

[0026] (3) After culturing for 3 days, the mixture was centrifuged at 8000 r / min for 5 min. The solid after centrifugation was washed three times with sterile saline to obtain the biochar-fixing bacteria HC-SRB.

[0027] (4) preparing a culture medium with a pH gradient of 5.5, 5.0, 4.5, and 4.0, with the corresponding divalent iron ion content being 50 mg / L, 75 mg / L, 100 mg / L, and 125 mg / L, respectively, and packaging the culture medium in 100 ml anaerobic bottles, passing nitrogen gas, sterilizing, and cooling for later use;

[0028] (5) HC-SRB and SRB bacterial suspensions were inoculated into the culture medium at the same biomass and at an inoculum rate of 10%. 2 ml of liquid was extracted from each anaerobic bottle at 0 h, 24 h, 48 h, and 72 h, and filtered using a 0.45 μm polyethersulfone filter membrane;

[0029] (6) Determine the pH and sulfate content in each bottle. Figure 1 and attached Figure 2 shown.

[0030] By the attached Figure 1 It can be seen that 3 days after the addition of HC-SRB, the pH of the anaerobic bottles with pH values ​​of 5.5, 5.0, and 4.5 increased significantly; 3 days after the addition of the bacterial solution, the pH in each anaerobic bottle did not increase significantly.

[0031] By the attached Figure 2It can be seen that 3 days after the addition of HC-SRB, the sulfate content in the anaerobic bottles with pH values ​​of 5.5, 5.0, and 4.5 decreased significantly; 3 days after the addition of the bacterial solution, the sulfate content in each anaerobic bottle did not decrease significantly.

[0032] By the attached Figure 1 and attached Figure 2 It can be seen that HC-SRB significantly improved the rate and acid resistance of SRB-treated AMD.

Claims

1. A method for preparing a sulfate-reducing bacteria (SRB) agent using activated carbon (HC), characterized by comprising the following steps:

1. Place Postgate C medium dissolved in distilled water in a sealed anaerobic bottle, adjust the pH to 7.0-7.2, blow nitrogen for 15 minutes, and sterilize at 121°C for 20 minutes; 2. After the culture medium has cooled to room temperature, add HC and 20% SRB bacterial solution to the culture medium and place it in a 35°C constant temperature incubator for static culture; 3. After culturing for 3 days, the mixture was centrifuged at 8000 r / min for 5 min; the solid after centrifugation was washed 3 times with sterile saline, which was the activated carbon fixed bacteria HC-SRB; 4. Mix HC-SRB and fresh Postgate C medium and store in a 4°C refrigerator.

2. The method for preparing SRB bacterial agent using HC according to claim 1, characterized in that: The components of the Postgate C culture medium in step 1 are: KH2PO4 (0.5g / L), MgSO4·7H2O (1.5g / L), Na2SO4 (1.2g / L), CaCl2 (0.06g / L), Fe(NH4)2·(SO4)2·6H2O (0.3g / L), NaCl (1.0g / L), NH4Cl (1.0g / L), sodium lactate (3.5ml / L), yeast powder (1.0g / L), L-cysteine ​​(0.3g / L), and ascorbic acid (0.3g / L).

3. The method for preparing SRB bacterial agent using HC according to claim 1, characterized in that: The particle size of HC in step 2 is 200 mesh; the amount of HC added is 0.6 g / L.

4. The method for preparing SRB bacterial agent using HC according to claim 1, characterized in that: In step 2, HC is used to fix SRB by adding HC to Postgate C medium at the same time.

5. The method for preparing SRB bacterial agent using HC according to claim 1, characterized in that: In the step 3, the time for HC to fix SRB is 3 days, the centrifugal speed for obtaining HC-SRB is 8000 r / min, and the centrifugal time is 5 minutes.

6. The method for preparing SRB bacterial agent using HC according to claim 1, characterized in that: The HC-SRB in step 4 was stored in a 4°C refrigerator.

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