Method for preparing sulfate reducing bacteria (SRB) microbial inoculum by using nano zero-valent iron (nZVI)
By using nZVI to fix SRB bacteria, nZVI-SRB bacteria agent is formed, which solves the problem of SRB growth restriction in the prior art under acidic environment, and achieves efficient treatment of acid sulfate wastewater and improves acid resistance.
Patent Information
- Application Number
- CN202311178322.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2023-09-13
- Publication Date
- 2025-03-14
AI Technical Summary
The prior art is difficult to effectively treat acidic sulfate wastewater, especially in acidic environments. The growth and metabolism of SRB are restricted, limiting the application of SRB in the treatment of acidic sulfate wastewater.
By using iron zero-valent iron (nZVI) as a carrier, an SRB bacteria agent was prepared. By mixing nZVI with SRB bacterial solution and cultured on stand under specific culture conditions, the SRB bacteria were fixed on nZVI to form nZVI fixed bacteria (nZVI-SRB).
This method not only increases the rate of SRB treating acid sulfate wastewater, but also significantly improves the acid resistance of SRB, which can effectively reduce the sulfate content at a lower pH environment.
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Figure CN119614408A_ABST
Abstract
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 nZVI as a carrier of SRB. Background Art
[0002] With the rapid development of industrialization, urbanization and human intervention, the global water quality continues to deteriorate, causing great harm to human health and the environment. Due to human activities, a wide range of pollutants have been detected in various water systems, including groundwater, seawater and wastewater, which increases the challenge of treatment. Organic (such as dyes and phthalates), inorganic (such as heavy metals), microorganisms, suspended solids and emerging pollutants (such as drugs) have been detected in water. Among these pollutants, sulfate pollutants have received widespread attention due to their significant increase in concentration in groundwater and surface water.
[0003] High concentrations of sulfate are mainly produced by anthropogenic processes such as mining, smelting industry, fossil fuel combustion, steel manufacturing, glass, soap, fungicide, tanneries, pulp and paper mills, printing and flue gas desulfurization, molasses, dyeing, landfill leachate, and natural sources such as volcanic decomposition, organic deposition and sea salt burning. Sulfate ions are found in ephemeral quartz, chalcocite, barite, gypsum, etc. Most sulfate minerals are highly soluble in water, except for the hydroxide sulfates of lead, barium and strontium. Water-soluble sulfate ions enter the groundwater and then penetrate into the organism through water, or sulfate is reduced to sulfide in the process of biological reduction, and then accumulates in the organism, eventually endangering human health.
[0004] At present, the treatment technologies for acidic sulfate wastewater mainly include chemical treatment technology, ion exchange technology, bioremediation technology, electrocoagulation technology, adsorption technology, membrane technology and hybrid technology. The selection of appropriate sulfate removal technology depends on several parameters, such as economic feasibility, energy consumption, by-product formation and environmental regulations. The method of using SRB to treat acidic sulfate wastewater is low-cost, clean and environmentally friendly, and has no secondary pollution. It is a highly promising bioremediation technology. However, the growth of SRB is affected by temperature, pH, COD, heavy metals and SO4 2- Affected by factors such as concentration, the pH of acidic sulfate wastewater is generally less than 5, which is not suitable for the growth and metabolism of SRB, greatly limiting the application of SRB in the treatment of acidic sulfate wastewater. Summary of the invention
[0005] The purpose of the present invention is to overcome the deficiencies in the above-mentioned prior art, provide a method for preparing an SRB bacterial agent that is easy to operate, and improve the rate and acid resistance of SRB in treating acidic sulfate wastewater.
[0006] To achieve the above object, the technical solution of the present invention is as follows:
[0007] A method for preparing an SRB bacterial agent using nZVI, 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 nZVI 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 to obtain nZVI-fixed bacteria nZVI-SRB;
[0011] 4. Mix nZVI-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 / 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).
[0013] The amount of nZVI added in step 2 is: 0.6 g / L.
[0014] In the step 2, nZVI is used to fix SRB by adding it to Postgate C culture medium at the same time.
[0015] In the step 3, the time for nZVI to fix SRB is 3 days, the centrifugation speed for obtaining nZVI-SRB is 8000 r / min, and the centrifugation time is 5 minutes.
[0016] The nZVI-SRB in step 4 was stored in a 4°C refrigerator.
[0017] The beneficial effects of the present invention are:
[0018] (1) The nZVI used in the present invention has a small particle size, a large specific surface area, and a high reaction activity, and can provide a high-quality ORP environment for the growth of SRB, thereby promoting the growth of SRB;
[0019] (2) The present invention can not only effectively improve the rate of SRB in treating acidic sulfate wastewater, but also improve the acid resistance of SRB. BRIEF DESCRIPTION OF THE DRAWINGS
[0020] Figure 1 : pH of AMD with different pH values after being treated with nZVI-SRB and SRB bacterial solutions for 72 h;
[0021] Figure 2 : Sulfate content of AMD with different pH values after treatment with nZVI-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 nZVI, comprising the following steps:
[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, nZVI 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 nZVI-fixed bacteria nZVI-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) nZVI-SRB and SRB bacterial suspensions were inoculated into the culture medium at the same biomass and at an inoculum size 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 1It can be seen that 3 days after the addition of nZVI-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 2 It can be seen that 3 days after the addition of nZVI-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 nZVI-SRB significantly improved the rate and acid resistance of SRB in treating acidic sulfate wastewater.
Claims
1. A method for preparing a sulfate-reducing bacteria (SRB) agent using nano zero-valent iron (nZVI), 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 nZVI 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 three times with sterile saline to obtain nZVI-fixed bacteria nZVI-SRB; 4. Mix nZVI-SRB and fresh Postgate C medium and store in a 4°C refrigerator.
2. A method for preparing SRB bacterial agent using nZVI 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. A method for preparing SRB bacterial agent using nZVI according to claim 1, characterized in that: The amount of nZVI added in step 2 is 0.6 g / L.
4. The method for preparing SRB bacterial agent using nZVI according to claim 1, characterized in that: In the step 2, nZVI is used to fix SRB by adding it to Postgate C culture medium at the same time.
5. The method for preparing SRB bacterial agent using nZVI according to claim 1, characterized in that: In the step 3, the time for nZVI to fix SRB is 3 days, the centrifugation speed for obtaining nZVI-SRB is 8000 r / min, and the centrifugation time is 5 minutes.
6. The method for preparing SRB bacterial agent using nZVI according to claim 1, characterized in that: The nZVI-SRB in step 4 was stored in a 4°C refrigerator.