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Matlock, M. M., Howerton, B. S., & Atwood, D. A. (2002). Chemical precipitation of heavy metals from acid mine drainage. Water Res, 36(19), 4757–4764.
Abstract: The 1,3-benzenediamidoethanethiol dianion (BDET, known commercially as MetX) has been developed to selectively and irreversibly bind soft heavy metals from aqueous solution. In the present study BDET was found to remove >90% of several toxic or problematic metals from AMD samples taken from an abandoned mine in Pikeville, Kentucky. The concentrations of metals such as iron, may be reduced at pH 4.5 from 194 ppm to below 0.009 ppm. The formation of stoichiomietric BDET-metal precipitates in this process was confirmed using X-ray powder diffraction (XRD), proton nuclear magnetic resonance (1H NMR), and infrared spectroscopy (IR).
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Scholz, M. (2002). Mature experimental constructed wetlands treating urban water receiving high metal loads. Biotechnology Progress, 18(6), 1257–1264.
Abstract: The aim was to assess over 2 years the treatment efficiencies of vertical-flow wetland filters containing macrophytes and granular media of different. adsorption capacities. Different concentrations of lead and copper sulfate (constant for 1 year each) were added to urban beck inflow water in order to simulate pretreated (pH adjustment assumed) mine wastewater. After 1 year of operation, the inflow concentrations for lead and copper were increased from 1.30 to 2.98 and from 0.98 to 1.93 mg/L, respectively. However, the metal mass load rates (mg/m(2)/d) were increased by a factor of approximately 4.9 for lead and 4.3 for copper. No breakthrough of metals was recorded. Lead and copper accumulated in the biomass of the litter zone and rhizomes of the macrophytes. Furthermore, microbiological activity decreased during the second year of operation. Bioindicators such as ciliated protozoa and zooplankton decreased sharply in numbers but diatoms increased. In conclusion, the use of macrophytes and, adsorption media did not significantly enhance the filtration of lead and copper. Particulate lead is removed by filtration processes including straining. Furthermore, some expensive and time-consuming water quality variables can be predicted with less expensive ones such as temperature in order to reduce sampling costs.
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Chalaturnyk, R. J., Scott, J. D., & Ozum, B. (2002). Management of Oil Sands Tailings. Pet. Sci. Technol., 20(9-10), 1025–1046.
Abstract: In Alberta, oil sands bitumen is utilized for synthetic crude oil (SCO) production by surface mining, bitumen extraction followed by primary (coking) and secondary (catalytic hydro-treating) upgrading processes. SCO is further refined in specially designed or slightly modified conventional refineries into transportation fuels. Oil sands tailings, composed of water, sands, silt, clay and residual bitumen, is produced as a byproduct of the bitumen extraction process. The tailings have poor consolidation and Water release characteristics. For twenty years, significant research has been performed to improve the consolidation and water release characteristics of the tailings. Several processes were developed for the management of oil sands tailings, resulting in different recovered water characteristics, consolidation rates and consolidated solid characteristics. These processes may affect the performance of the overall plant operations. Apex Engineering Inc. (AEI) has been developing a process for, thesame purpose. In this process oil sands tailings are treated with Ca(OH)(2) lime and CO2 and thickened using a suitable thickener. The combination of chemical treatment and the use of a thickener results in the release of process water in short retention times without accumulation of any ions in the recovered water. This makes it possible to recycle the recovered water, probably after a chemical treatment, as warm as possible, which improves the thermal efficiency of the extraction process. The AEI Process can be applied in many different fashions for the management of different fractions of the tailings effluent, depending on the overall plant operating priorities.
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Fischer, R., Luckner, L., Peukert, D., Reißig, H., & Roßbach, B. (2002). Einsatz alkalischer Substanzen zur Verbesserung der Wasserqualität in Bergbaukippen. Use of alcine substances for the improvement of water quality in mining areas. Das Gas und Wasserfach. Ausgabe Wasser, Abwasser, 143(12), 891–898.
Abstract: Eisendisulfidminerale im Abraum von Braunkohlentagebauen können nach ihrer Verwitterung im wiederaufsteigenden Grundwasser erhebliche Güteverschlechterungen hinsichtlich pH-Wert, Schwermetall- und Sulfatgehalt verursachen. Diesen kann durch Zusätze alkalischer Substanzen zum Abraum wie Kalkstein, Dolomit und Kraftwerksasche bzw. Gemischen dieser Stoffe entgegengewirkt werden. Die Ergebnisse entsprechender Untersuchungen sowie die naturwissenschaftlichen Grundlagen der Eisendisulfidverwitterung werden im Beitrag dargestellt und ein Anwendungsbeispiel beschrieben. Grundlagen zur Berechnung der einzusetzenden Kalk- oder Aschemengen (bzw. Gemische der beiden Substanzen) sind die Bestimmung der oxidierbaren Sulfidminerale in den einzelnen geologischen Schichten sowie die Bestimmung der Pufferkapazität der Asche bzw. des Kalksteins. Besonders Vorteilhaft ist der Einsatz alkalischer Substanzen dort, wo durch vorhandene hohe Pyrit- und Markasitkonzentrationen mit einer erheblichen Versauerung des Grundwassers gerechnet und dadurch eine potentielle Beeinträchtigung von Grundwassernutzern erwartet werden muss. Solche Bedingungen sind im Rheinischen Braunkohlerevier, insbesondere im Umfeld des Tagebaus Garzweiler II (RWE Rheinbraun AG) gegeben. Derzeit werden im Tagebau Garzweiler bereits 40000 t Kalkstein dem Abraum beigemischt. Auch für das Lausitzer Braunkohlenrevier könnte ein Einsatz alkalischer Substanzen in Betracht gezogen werden.
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Burgess, J. E., & Stuetz, R. M. (2002). Activated Sludge for the Treatment of Sulphur-rich Wastewaters. Miner. Eng., 15(11), 839–846.
Abstract: The aim of this investigation was to assess the potential of activated sludge for the remediation of sulphur-rich wastewaters. A pilot-scale activated sludge plant was acclimatised to a low load of sulphide and operated as a flow-through unit. Additional sludge samples from different full-scale plants were compared with the acclimatised and unacclimatised sludges using batch absorption tests. The effects of sludge source and acclimatisation on the ability of the sludge to biodegrade high loads of sulphide were evaluated. Acclimatisation to low-sulphide concentrations enabled the sludge to degrade subsequent high loads which were toxic to unacclimatised sludge. Acclimatisation was seen to be an effect of selection pressure on the biomass, suggesting that the treatment capability of activated sludge will develop after acclimation, indicating potential for treatment of acid mine drainage (AMD) by a standard wastewater treatment process. Existing options for biological treatment of AMD are described and the potential of activated sludge treatment for AMD discussed in comparison with existing technologies. (C) 2002 Elsevier Science Ltd.
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