Treatment of Acid Mine Drainage with Sulphate-reducing Bacteria Using a Two stage Bioremediation Process (original) (raw)
Related papers
Water, Air, and Soil Pollution, 2005
Acid mine drainage (AMD) is a serious environmental problem resulting from extensive sulphide mining activities. The old copper mine of S. Domingos in Southeast Portugal is an example of such a situation. The abandoned open-pit from the mining operations resulted in the creation of a large pit lake with acidic water (pH∼2) and high contents of sulphate and heavy metals. Sulphatereducing biological processes have been studied as a remediation technology for this problem. A new application based on a simple and semi-continuous process for the treatment of S. Domingos AMD has been presented herein. Experiments using bench scale fixed-bed column bioreactors were carried out to evaluate the efficiency of the process. Sewage, anaerobic sludge and soil from the mining area were tested as solid matrices and/or inocula, as well as sources of complex organic substrates. The addition of lactose as a supplementary carbon source, easily available at zero cost or at negative cost in the effluents of the local cheese industries, was also tested. The data obtained indicate that it is possible to use the matrices tested for the production of sulphide by sulphate reduction, and that the regular addition of lactose is effective. Results showed that the process is efficient for the precipitation of the main dissolved metals, for the reduction in the sulphate content and, most importantly, for the neutralization of the AMD. Moreover, the use of soil as solid support also showed the possibility of using this process for the decontamination of both waters and soils.
Bioremediation of an industrial acid mine water by metal-tolerant sulphate-reducing bacteria
Minerals Engineering, 2001
The microbiological diversity associated with mining environments is a very well proven fact. One of the communities appearing in these environments is that formed by anaerobic sulphate-reducing bacteria (SRB) which can be used for the decontamination of acid mine drainage waters. In this work, the potential of a mixed population of SRB, isolated from the bottom of a pyritic tailing pond situated in the Spanish pyritic Belt, has been investigated with the main objective of treating the effluent generated in the same disposal site. The efficiency of the system is based on the presence of an important amount of reducing agents contained in the acid mine drainage received in the pond. Results showed that this option is effective for the precipitation of the dissolved metals (copper and iron), for the reduction and removal of sulphates and even for the alkalising of the waters. SRB were able to remove up to 9,000 ppm of sulphate ion efficiently, to grow in the presence of up to lOO ppm of copper and 30 ppm of iron, and alkalise the medium, provided that this was not extremely acidic (pH>4). Finally, according to the results obtained, the possibility of applying this method to the treatment of a real effluent is discussed.
Acta Montanistica Slovaca, 2012
The impacts of AMD pollution on biological systems are mostly severe and the problem may persist from many decades to thousands of years. Consequently AMD prior to being released into the environment must be treated to meet government standards for the amount of metal and non-metal ions contained in the water. One of the best available technologies for the removal of metals from AMD is precipitation as metal sulphides. SRB applications for AMD treatment involve a few principal stages. The first stage is the cultivation of SRB i.e. the bacterial sulphate reduction. At the laboratory conditions the sodium lactate is the energetic substrate for the growth of bacteria. Its price is not economic for the application in the practice and is needed investigate the alternative substitutes. The aim of this work was the cultivation of SRB using the selected energetic substrates such as: calcium lactate, ethanol, saccharose, glucose and whey. Experimental studies confirm that in the regard to th...
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
Bioremediation of acid mine drainage coupled with domestic wastewater treatment
Water Science & Technology, 2012
Acid mine drainage (AMD) – characterized by high acidity and elevated sulfate and metal concentrations – represents a big environmental concern. Biological sulfate reduction has become an alternative to the classical physicochemical methods. In this study, domestic wastewater (DW) was tested as a cost-effective carbon-source for the remediation of AMD. Sediments from Tinto River, an extreme acidic environment with an elevated concentration of metals, were used as inoculum. Three anaerobic bioreactors with different microbial supports were fed with a 1:10 (v:v) mixture of synthetic AMD:DW. Around 50% of the organic matter present in the DW co-precipitated with the metals from the AMD previous to feeding the reactor. Therefore, the reactors had to be supplemented with an extra carbon-source (acetate) to achieve higher S elimination. Elevated removal efficiencies of chemical oxygen demand (COD) (>88%), sulfate (>75%), Fe (>85%) and other dissolved metals (>99% except for Mn...
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 %.
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.
Sudbury 2003 Bioremediation of Rock Drainage Using Sulphate-Reducing Bacteria
Dealing with high concentrations of sulphates and metals in mine drainage is one of the major problems associated with many base metal and coal mines. Large volumes of acidic water can be generated from mine workings, waste rock piles and tailings. Usually, this acid rock drainage (ARD) cannot be disposed off until it has been treated in some way as it poses a direct threat to drinking water, agriculture, vegetation, wildlife and waterways. Traditional active treatment processes such as reverse osmosis or the addition of chemicals employed are often not very efficient and can be quite costly. In some cases they are simply not feasible. Therefore, alternative methods have to be considered. Anaerobic bioremediation, a process in which sulphate-reducing bacteria (SRB) are used to decontaminate mine drainage in a stand alone bioreactor or one forming part of a constructed wetland (CW) system is such an alternative: Sulphate-reducing bacteria are able to remove metals such as iron, zinc, copper, and others, raise the pH of the water and lower sulphate concentrations. With anaerobic bioremediation, SRB reduce metal sulphates to insoluble sulphides as part of their metabolic activity. These metal sulfides precipitate, removing them from the water. Indeed, some species of SRB even are able to reduce otherwise hard-to-handle metals, for example converting soluble uranium (VI) to insoluble uranium (IV). Additionally, in anaerobic bioreactors, metals such as aluminum that cannot be removed by precipitation can be removed by biosorption, either through accumulation of the ions in bacterial cells or by adsorption on their celluar surfaces. At the same time, the reduction of sulphate anions by the SRB uses up protons, and this in turn raises the pH. Conditions in CWs can serve two purposes with this form of bioremediation: they provide carbon and energy sources for autochthonous bacteria in form of organic matter from the plants and/or added waste products, and can also provide a level of phytoremediation (bioremediation involving plants) through adsorption of dissolved metals on the surfaces of their rhizomes (sub-surface root nodules). With engineered wetlands (EWs), a more advanced, semi-passive form of constructed wetlands, these processes can be enhanced and/or wetland plants even can be selected that have further phytoremediating properties which allow them to take up and metabolize organics and heavy metals from the mine drainage passing through their root systems. The SRB-mediated anaerobic bioremediation process is not limited to acidic mine waters, it can be applied to various industrial waste waters of different pH which are high in sulphates and metals and/or organic contaminants. The process can be designed in different ways to accommodate different locations and natures of the contaminated waters.
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).
International Biodeterioration & Biodegradation, 2011
The performance of two up-flow anaerobic packed bed systems (UAPB) to treat acid mine drainage (AMD) from the Portuguese mines São Domingos and Tinoca was investigated. The response of bacterial populations to influent characteristics was also analysed by temperature gradient gel electrophoresis (TGGE). Effective neutralisation (pH raised from 2.8 to 6.5) and removal of metals (>99%) and sulphate (>72%) were observed independently of the AMD source. TGGE fingerprinting and phylogenetic analysis of 16S rRNA gene revealed that the structure of the bacterial consortia developed in each bioreactor was different. The main bacterial groups involved in the treatment of AMD from Tinoca mine were Desulfovibrio sp., Clostridium sp., Desulfitobacterium sp. and members of Bacteroidales order. These bacterial groups were also present in the community developed in the UAPB fed with AMD from São Domingos mine but an unidentified bacterium and bacteria affiliated to Citrobacter and Cronobacter genera were detected only in this last system. The results of present study showed that the AMD source fed to the system was determinant for the establishment of different bacterial populations. Furthermore, the potential of the bioremediation systems for the production of water for irrigation purposes was demonstrated.