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Author LaPointe, F.; Fytas, K.; McConchie, D.
Title Using permeable reactive barriers for the treatment of acid rock drainage Type Journal Article
Year 2005 Publication International journal of surface mining, reclamation and environment Abbreviated Journal
Volume 19 Issue 1 Pages 57-65
Keywords Pollution and waste management non radioactive Groundwater problems and environmental effects geological abstracts: environmental geology (72 14 2) geomechanics abstracts: excavations (77 10 10) waste management remediation mining industry pollution control acid mine drainage reactive barrier aluminium industry effluents industrial waste mineral processing industry oxidation waste handling permeable reactive barriers acid rock drainage treatment acid mine drainage environmental problem Canadian mineral industry oxidation sulphide minerals mine waste mine tailings heavy metals acid remediation technology metallurgical residues aluminium extraction industry acid mine effluents Manufacturing and Production acid mine drainage Bauxsol Canada disposal barriers effluents experimental studies heavy metals instruments oxidation permeable reactive barriers pollutants pollution pyrite pyrrhotite remediation sulfides tailings waste disposal waste management
Abstract Acid mine drainage (AMD) is the most serious environmental problem facing the Canadian mineral industry today. It results from oxidation of sulphide minerals (e.g. pyrite or pyrrhotite) contained in mine waste or mine tailings and is characterized by acid effluents rich in heavy metals that are released into the environment. A new acid remediation technology is presented, by which metallurgical residues from the aluminium extraction industry are used to construct permeable reactive barriers (PRBs) to treat acid mine effluents. This technology is very promising for treating acid mine effluents in order to decrease their harmful environmental effects
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ISSN 1389-5265 ISBN Medium
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Notes Using permeable reactive barriers for the treatment of acid rock drainage; 8467608; Journal Paper; SilverPlatter; Ovid Technologies Approved no
Call Number CBU @ c.wolke @ 16786 Serial 12
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Author Cravotta, C.A., III; Trahan, M.K.
Title Limestone drains to increase pH and remove dissolved metals from acidic mine drainage Type Journal Article
Year 1999 Publication Appl. Geochem. Abbreviated Journal
Volume 14 Issue 5 Pages 581-606
Keywords manganese oxide redox processes sulfate waters iron-oxides adsorption ions oxidation surfaces environments aluminum
Abstract Despite encrustation by Fe and Al hydroxides, limestone can be effective for remediation of acidic mine drainage (AMD). Samples of water and limestone (CaCO3) were collected periodically for 1 a at 3 identical limestone-filled drains in Pennsylvania to evaluate the attenuation of dissolved metals and the effects of pH and Fe- and Al-hydrolysis products on the rate of CaCO3 dissolution. The influent was acidic and relatively dilute (pH < 4; acidity < 90 mg) but contained 1-4 mg . L-1 of O-2, Fe3+, Al3+ and Mn2+. The total retention time in the oxic limestone drains (OLDs) ranged from 1.0 to 3.1 hr. Effluent remained oxic (O-2 > 1 mg . L-1) but was near neutral (pH = 6.2-7.0); Fe and Al decreased to less than 5% of influent concentrations. As pH increased near the inflow, hydrous Fe and Al oxides precipitated in the OLDs, The hydrous oxides, nominally Fe(OH)(3) and Al(OH)(3), were visible as loosely bound, orange-yellow coatings on limestone near the inflow. As time elapsed, Fe(OH)(3) and Al(OH)(3) particles were transported downflow. The accumulation of hydrous oxides and elevated pH (> 5) in the downflow part of the OLDs promoted sorption and coprecipitation of dissolved Mn, Cu, Co, Ni and Zn as indicated by decreased concentrations of the metals in effluent and their enrichment relative to Fe in hydrous-oxide particles and coatings on limestone. Despite thick (similar to 1 mm) hydrous-oxide coatings on limestone near the inflow, CaCO3 dissolution was more rapid near the inflow than at downflow points within and the OLD where the limestone was not coated. The high rates of CaCO3 dissolution and Fe(OH3) precipitation were associated with the relatively low pH and high Fe3+ concentration near the inflow. The rate of CaCO3 dissolution decreased with increased pH and concentrations of Ca2+ and HCO3- and decreased Pco(2). Because overall efficiency is increased by combining neutralization and hydrolysis reactions, an OLD followed by a settling pond requires less land area than needed for a two-stagetreatment system consisting of an anoxic limestone drain and oxidation-settling pond or wetland. To facilitate removal of hydrous-oxide sludge, a perforated-pipe subdrain can be installed within an OLD. (C) 1999 Elsevier Science Ltd.
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ISSN 0883-2927 ISBN Medium
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Notes Jul; Limestone drains to increase pH and remove dissolved metals from acidic mine drainage; Isi:000080043300004; file:///C:/Dokumente%20und%20Einstellungen/Stefan/Eigene%20Dateien/Artikel/10102.pdf; AMD ISI | Wolkersdorfer Approved no
Call Number CBU @ c.wolke @ 17470 Serial 22
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Author Jarvis, A.P.; Younger, P.L.
Title Passive treatment of ferruginous mine waters using high surface area media Type Journal Article
Year 2001 Publication Water Res. Abbreviated Journal
Volume 35 Issue 15 Pages 3643-3648
Keywords mine water treatment passive treatment mine water accretion oxidation iron manganese water treatment
Abstract Rapid oxidation and accretion of iron onto high surface area media has been investigated as a potential passive treatment option for ferruginous, net-alkaline minewaters. Two pilot-scale reactors were installed at a site in County Durham, UK. Each 2.0m high cylinder contained different high surface area plastic trickling filter media. Ferruginous minewater was fed downwards over the media at various flow-rates with the objective of establishing the efficiency of iron removal at different loading rates. Residence time of water within the reactors was between 70 and 360s depending on the flow-rate (1 and 12l/min, respectively). Average influent total iron concentration for the duration of these experiments was 1.43mg/l (range 1.08-1.84mg/l; n=16), whilst effluent iron concentrations averaged 0.41mg/l (range 0.20-1.04mg/l; n=15) for Reactor A and 0.38mg/l (range 0.11-0.93mg/l; n=16) for Reactor B. There is a strong correlation between influent iron load and iron removal rate. Even at the highest loading rates (approximately 31.6g/day) 43% and 49% of the total iron load was removed in Reactors A and B, respectively. At low manganese loading rates (approximately 0.50-0.90g/day) over 50% of the manganese was removed in Reactor B. Iron removal rate (g/m3/d) increases linearly with loading rate (g/day) up to 14g/d and the slope of the line indicates that a mean of 85% of the iron is removed. In conclusion, it appears that the oxidation and accretion of ochre on high surface area media may be a promising alternative passive technology to constructed wetlands at certain sites.
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ISSN 0043-1354 ISBN Medium
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Notes Oct; Passive treatment of ferruginous mine waters using high surface area media; 9; file:///C:/Dokumente%20und%20Einstellungen/Stefan/Eigene%20Dateien/Artikel/9698.pdf; AMD ISI | Wolkersdorfer Approved no
Call Number CBU @ c.wolke @ 9698 Serial 27
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Author Evangelou, V.P.
Title Pyrite microencapsulation technologies: Principles and potential field application Type Journal Article
Year 2001 Publication Ecological Engineering Abbreviated Journal
Volume 17 Issue 2-3 Pages 165-178
Keywords mine water treatment Acid mine drainage Acidity Alkalinity Amelioration Coating Oxidation Surface reactions
Abstract In nature, pyrite is initially oxidized by atmospheric O2, releasing acidity and Fe2+. At pH below 3.5, Fe2+ is rapidly oxidized by T. ferrooxidans to Fe3+, which oxidizes pyrite at a much faster rate than O2. Commonly, limestone is used to prevent pyrite oxidation. This approach, however, has a short span of effectiveness because after treatment the surfaces of pyrite particles remain exposed to atmospheric O2 and oxidation continuous abiotically. Currently, a proposed mechanism for explaining non-microbial pyrite oxidation in high pH environments is the involvement of OH- in an inner-sphere electron-OH exchange between pyrite/surface-exposed disulfide and pyrite/surface-Fe(III)(OH)n3-n complex and/or formation of a weak electrostatic pyrite/surface-CO3 complex which enhances the chemical oxidation of Fe2+. The above infer that limestone application to pyritic geologic material treats only the symptoms of pyrite oxidation through acid mine drainage neutralization but accelerates non-microbial pyrite oxidation. Therefore, only a pyrite/surface coating capable of inhibiting O2 diffusion is expected to control long-term oxidation and acid drainage production. The objective of this study was to examine the feasibility in controlling pyrite oxidation by creating, on pyrite surfaces, an impermeable phosphate or silica coating that would prevent either O2 or Fe3+ from further oxidizing pyrite. The mechanism underlying this coating approach involves leaching mine waste with a coating solution composed of H2O2 or hypochlorite, KH2PO4 or H4SiO4, and sodium acetate (NaAC) or limestone. During the leaching process, H2O2 or hypochlorite oxidizes pyrite and produces Fe3+ so that iron phosphate or iron silicate precipitates as a coating on pyrite surfaces. The purpose of NaAC or limestone is to eliminate the inhibitory effect of the protons (produced during pyrite oxidation) on the precipitation of iron phosphate or silicate and to generate iron-oxide pyrite coating, which is also expected to inhibit pyrite oxidation. The results showed that iron phosphate or silicate coating could be established on pyrite by leaching it with a solution composed of: (1) H2O2 0.018-0.16 M; (2) phosphate or silicate 10-3 to 10-2 M; (3) coating-solution pH [approximate]5-6; and (4) NaAC as low as 0.01 M. Leachates from column experiments also showed that silicate coatings produced the least amount of sulfate relative to the control, limestone and phosphate treatments. On the other hand, limestone maintained the leachate near neutral pH but produced more sulfate than the control.
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ISSN 0925-8574 ISBN Medium
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Notes July 01; Pyrite microencapsulation technologies: Principles and potential field application; file:///C:/Dokumente%20und%20Einstellungen/Stefan/Eigene%20Dateien/Artikel/10063.pdf; Science Direct Approved no
Call Number CBU @ c.wolke @ 10063 Serial 37
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Author Burgess, J.E.; Stuetz, R.M.
Title Activated Sludge for the Treatment of Sulphur-rich Wastewaters Type Journal Article
Year 2002 Publication Miner. Eng. Abbreviated Journal
Volume 15 Issue 11 Pages 839-846
Keywords acid rock drainage biooxidation biotechnology environmental waste processing acid-mine drainage sulfate-reducing bacteria biological treatment waste-water metals acclimation remediation oxidation reduction removal
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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ISSN 0892-6875 ISBN Medium
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Notes Nov.; Activated Sludge for the Treatment of Sulphur-rich Wastewaters; Isi:000179970500009; file:///C:/Dokumente%20und%20Einstellungen/Stefan/Eigene%20Dateien/Artikel/10093.pdf; AMD ISI | Wolkersdorfer Approved no
Call Number CBU @ c.wolke @ 10093 Serial 40
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