Bioremediation of an industrial acid mine water by metal-tolerant sulphate-reducing bacteria (original) (raw)
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Acid mine drainage (AMD) causes several environmental problems in many countries. The use of biological processes with sulphate-reducing bacteria (SRB) has great potential within environmental biotechnology. The aim of this study was to develop a bioremediation system, using a mixed culture of SRB, for the treatment of AMD from São Domingos mine. Sulphate and heavy metals (Fe, Cu and Zn) concentrations, pH and Eh were monitored during 243 days. The process that was developed consisted of two stages that proved highly efficient at AMD neutralization and the removal of sulphates and the heavy metals iron, copper and zinc .
Treatment by sulfate-reducing bacteria of Chessy acid-mine drainage and metals recovery
Chemical Engineering …, 2001
Acid-mine drainage can contain high concentrations of heavy metals and release of these contaminants into the environment is generally avoided by lime neutralization. However, this classical treatment is expensive and generates large amounts of residual sludge. The selective precipitation of metals using H S produced biologically by sulfate-reducing bacteria has been proposed as an alternative process. Here, we report on experiments using real e%uent from the disused Chessy-les-Mines mine-site at the laboratory pilot scale. A "xed-bed bioreactor, fed with an H /CO mixture, was used in conjunction with a gas stripping column. The maximum rate of hydrogen transfer in the bioreactor was determined before inoculation. k * a was deduced from measurements of O using Higbie and Danckwert's models which predict a dependence on di!usivity. The dynamic method of physical absorption and desorption was used. The maximum rate of H transfer suggests that this step should not be a limiting factor. However, an increase in H #ow rate was observed to induce an increase in sulfate reduction rate. For the precipitation step, the gas mixture from the bioreactor was bubbled into a stirred reactor fed with the real e%uent. Cu and Zn could be selectively recovered at pH"2.8 and pH"3.5, respectively. Other impurities such as Ni and Fe could also be removed at pH"6 by sul"de precipitation. Part of the outlet stream from the bioreactor was used to regulate and maintain the pH during sul"de precipitation by feeding the outlet stream back into the bioreactor. The replacement of synthetic medium with real e%uent had a positive e!ect on sulfate reduction rate which increased by 30}40%. This improvement in bacterial e$ciency may be related to the large range of oligo-elements provided by the mine-water. The maximum sulfate reduction rate observed with the real e%uent was 200 mg l\ h\, corresponding to a residence time of 0.9 day. A preliminary cost estimation based on a treatment rate of 5 m h\ of a mine e%uent containing 5 g l\ SO\ is presented.
Low-Cost Biological Treatment of Metal-and Sulphate-Contaminated Mine Waters
2017
This paper describes the development of a passive biological sulphate reduction (BSR) process. Laboratory-scale test work was performed on a mine-impacted water from a South African coal mine. The substrate mix comprised wood chips, wood shavings, hay, lucerne and cow manure. Over 90 % sulphate removal was achieved, the pH level was raised to above 7, and metals were precipitated. Operating parameters were optimised to increase process kinetics. The results were used to design a pilot plant which will be operated at the coal mine, treating several hundred litres of water per day.
Sulphates Removal from Acid Mine Drainage
IOP Conference Series: Earth and Environmental Science, 2016
Acid mine drainage (AMD) are a worldwide problem leading to ecological destruction in river basins and the contamination of water sources. AMD are characterized by low pH and high content of heavy metals and sulphates. In order to minimize negative impacts of AMD appropriate treatment techniques has to be chosen. Treatment processes are focused on neutralizing, stabilizing and removing pollutants. From this reason efficient and environmental friendly methods are needed to be developed in order to reduce heavy metals as well as sulphates. Various methods are used for remediation of acid mine drainage, but any of them have been applied under commercial-scale conditions. Their application depends on geochemical, technical, natural, financial, and other factors. The aim of the present work was to interpret the study of biological methods for sulphates removal from AMD out-flowing from the shaft Pech of the deposit Smolník in Slovak Republic. In the experimental works AMD were used after removal of heavy metals by precipitation and sorption using the synthetic sorbent Slovakite. The base of the studied method for the sulphates elimination was the anaerobic bacterial sulphate reduction using sulphate-reducing bacteria (SRB) genera Desulfovibrio. SRB represent a group of bacteria that uses sulphates as a terminal electron acceptor for their metabolism. These bacteria realize the conversion of sulphate to hydrogen sulphide under anaerobic conditions. For the purposes of experiments a few variants of the selective medium DSM-63 culture media were used in term of the sulphates and sodium lactate contents in the selective medium as well as sulphates in the studied AMD.
Biological removal of anorganic pollutants from acid mine drainage
2015
Acid Mine Drainage (AMD) is one of the signifi cant environmental and fi nancial liabilities of the mining industry. Currently active mines, as well as mines that have been out of production for years, produce acidic waters with high concentration of sulphates and heavy metals. Treatment methods used to mitigate impact of AMD on the environment are focused on neutralizing, stabilizing and removing pollutants through various physical, chemical and biological processes. Th is paper reports the results of anorganic pollutants removal from AMD using sulphate reducing bacteria (SRB). Hydrogen sulphide produced by SRB for recovery of Cu and Zn has been used in the course of selective sequential precipitation process (SSP). In the next stage sulphates were removed from AMD by the biological anaerobic reduction. Th us, by this method removing of metals and sulphates has been achieved in successive discrete steps. Th e experiments were performed at laboratory condition using water collected from the site of the AMD outfl ow at the shaft Pech from the enclosed and fl ooded Smolnik sulphidic deposit (Slovakia).
Treatment of industrial effluents for neutralization and sulphate removal / Johannes Philippus Maree
2006
Acid mine drainage Barium sulphate Barium sulphide Calcium carbonate Dolomite Fluidised-bed Reactor Limestone Slaked lime Lime or Unslaked Acid water, rich in iron, produced when pyrite (FeS2) is oxidised in water due to the presence of air and iron oxidising bacteria B&04 Bas CaC03 A sedimentary rock of chemical composition, CaMg(CO3)z A column type reactor, packed with solid material, e.g. limestone, through which a fluid is moved, at a rate, high enough, to expand the volume in the reactor occupied by the solid particles. Sedimentary rock containing predominantly CaC03. CaO lime ABBREVIATIONS AMD BCL EDR GYPCIX HDS HRT MB OSI RO RWQO SRB UASB WLA Acid mine drainage Botswana Copper Limited Electrodialysis Gypsum counter current ion exchange High density sludge Hydraulic Retention Time Methanogenic bacteria Over saturation index Reverse osmosis Receiving water quality objective Sulphate Reducing Bacteria Up-flow Anaerobic Sludge Blanket Waste load allocation CHAPTER 1. SUMMARY OF THESIS 1.1 Background Acid mine water containing sulphate and high concentrations of dissolved heavy metals, including iron@), can have pH values as low as 2.5. Environmental pollution caused by such effluents are major contributors to the salinisation of receiving water, and may prove toxic to both fauna and flora. Acid, sulphate-rich solutions are produced bacteriologically fiom pyrite present in waste dumps fiom mining and metallurgical operations and fiom spent sulphuric acid used in chemical or metallurgical plants. The following large mine water treatment projects are currently receiving attention in South Afiica on a national level: Amanzi Water Project. The Amanzi project deals with the treatment of mine water (potentially 240 MVd) for the recovery of potable water and by-products (e.g. gypsum). Participating mines in the project are Randfontein Estates, First Wesgold, Durban Roodepoort Deep, Rand Leases, ERPM and Grootvlei. The pH of these waters varies fiom 2.8 to 6.0 and the sulphate concentrations h m 600 to 3 000 mgA (SWaMP Steering Committee, 1998). Olifants Forum. Polluted mine water, estimated at a volume of 130 MVd, is currently discharged to water courses on the Highveld. The mine water has a pH level between 2 and 4 and contains high sulphate concentrations (> 700 mgA) (Van Zyl, et al., 2000). Unless neutralized, such water may not be discharged into water courses. Lime is generally used for neutralization. Neutralization costs could be reduced significantly should lime be replaced with limestone. The cost of limestone is currently R130lt compared to R700lt for lime. Furthermore, increasing pressure is being exerted by the Department of Water Affairs and Forestry to enforce sulphate removal fiom effluent. Extensive studies have already been carried out by the mining industry to evaluate possible sulphate removal technologies. The high cost of these technologies are considered a major obstacle. Therefore, efforts to develop a cost-effective treatment process for the recovery of re-usable water fiom sulphate-rich effluents, is of national importance. 1.2 Objectives The objectives of this investigation were to develop processes whereby acid and/or sulphate-rich water can be treated. The specific aims of the investigation were to: Develop the integrated iron@)-oxidation and limestone neutralization process where powdered limestone is used for the neutralization of iron@)-rich acid water in a completely-mixed reactor (Chapters 3 and 4 and Patents 1-3). Develop the biological sulphate removal process for treatment of sulphate-rich effluents (Chapters 5 and 6). Develop the barium sulphide process for treatment of sulphate-rich effluents (Chapter 7). Develop a water flow and chemical mass balance model to identify the most costeffective treatment option for a water network (Chapter 8).
Acid Mine Drainage Treatment and Metal Removal Based on a Biological Sulfate-Reducing Process
Brazilian Journal of Chemical Engineering, 2018
The key purpose of this research was to explore the capacity of an anaerobic stirred batch reactor (ASBR) to deal with acid mine drainage (AMD) based on the activity of sulfate reducing bacteria (SRB). The tests showed that SRB produced hydrogen sulfide that precipitated the metals Fe 2+ , Zn 2+ , and Cu 2+. Ethanol was used as both the only source of carbon and electron donor. Throughout the experiment, the ratio of chemical oxygen demand (COD) to sulfate was constant at 1.0. The reactor was operated for 218 days using synthetic AMD at pH 4.0 containing 1000 and 1500 mg•L-1 of sulfate,100 mg•L-1 of Fe 2+ , 20 mg•L-1 Zn 2+ , and 5 mg•L-1 Cu 2+. The metal removal rates were greater than 99 %with effluent pH of 6.5 to 7.4. The sulfide concentration reached 56.6 mg•L-1 and sulfate removal was 43 to 65 %.
Bacterial Elimination of Sulphates from Mine Waters
Sulfates can be found in almost all types of water, in form of simple anion SO42-. Together with hydrogen carbonates and chlorides, sulfates are the main anions in natural water ecosystems. Sulfate concentration in characteristic groundwater and surface water ranges from ten to hundreds mg/L. Nowadays, the importance of the control of sulfate concentration in waste water increases. Contents of sulfates in rivers increase especially by waste water discharge, which comes mainly from metallurgical, mining, chemical, textile industry. Sulfate concentration in these waters ranges from tens to thousands of grams per liter. There are many technologies for sulfate removal, used in the waste water treatment, including biological-chemical processes. One of these methods is the reduction of sulfates by sulfate - reducing bacteria. The object of our study was to verify experimentally the possibility of using sulfate-reducing bacteria to remove sulfates from mine water originating from coal mine...
Diversity and Performance of Sulphate-Reducing Bacteria in Acid Mine Drainage Remediation Systems
Frontiers in Water-Energy-Nexus—Nature-Based Solutions, Advanced Technologies and Best Practices for Environmental Sustainability, 2019
Microbial diversity in acid mine drainage from eMalahleni, Mpumalanga, South Africa. Enrichment of SRB improves its performance in sulphate reduction. Microbial community shows synergy between SRB Proteobacteria and facultative Bacilli. Sulphate reduction of 85% and cadmium reduction of 98% were observed within 7 days of continuous operational mode. The microbial community showed wider substrates utilisation. Keywords Acid mine drainage Á Sulphate-reducing bacteria Á Heavy metal removal Á Microbial diversity 2 Materials and Methods Acid mine drainage (AMD) samples were collected as wastewater from a coal mining site in Mpumalanga Province, South Africa, using standard sampling procedure (EPA 2007). The samples were filtered using 45-lm cellulose acetate filters and stored in a polyethylene bottle