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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 Coulton, R.; Bullen, C.; Hallett, C.
Title The design and optimisation of active mine water treatment plants Type Journal Article
Year 2003 Publication Land Contam. Reclam. Abbreviated Journal
Volume 11 Issue 2 Pages 273-280
Keywords sludge mine water treatment mine water active treatment precipitation iron manganese high density sludge sulphide Groundwater problems and environmental effects Pollution and waste management non radioactive manganese sulfide pollutant removal iron water treatment mine drainage
Abstract This paper provides a 'state of the art' overview of active mine water treatment. The paper discusses the process and reagent selection options commonly available to the designer of an active mine water treatment plant. Comparisons are made between each of these options, based on technical and financial criteria. The various different treatment technologies available are reviewed and comparisons made between conventional precipitation (using hydroxides, sulphides and carbonates), high density sludge processes and super-saturation precipitation. The selection of reagents (quick lime, slaked lime, sodium hydroxide, sodium carbonate, magnesium hydroxide, and proprietary chemicals) is considered and a comparison made on the basis of reagent cost, ease of use, final effluent quality and sludge settling criteria. The choice of oxidising agent (air, pure oxygen, peroxide, etc.) for conversion of ferrous to ferric iron is also considered. Whole life costs comparisons (capital, operational and decommissioning) are made between conventional hydroxide precipitation and the high density sludge process, based on the actual treatment requirements for four different mine waters.
Address R. Coulton, Unipure Europe Ltd., Wonastow Road, Monmouth NP25 5JA, United Kingdom
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ISSN 0967-0513 ISBN Medium
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Notes The design and optimisation of active mine water treatment plants; 2530436; United-Kingdom 4; Geobase Approved no
Call Number CBU @ c.wolke @ 17513 Serial 59
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Author Barton, C.D.; Karathanasis, A.D.
Title Aerobic and anaerobic metal attenuation processes in a constructed wetland treating acid mine drainage Type Book Chapter
Year 1997 Publication AAPG Eastern Section and the Society for Organic Petrology joint meeting; abstracts Abbreviated Journal
Volume Issue Pages 1545
Keywords acid mine drainage aerobic environment air-water interface anaerobic environment attenuation buffers constructed wetlands controls diffusion iron manganese metals mineral composition pollution precipitation processes SEM data solubility solution sulfate ion sulfur wetlands X-ray diffraction data 22, Environmental geology
Abstract The use of constructed wetlands for acid mine drainage amelioration has become a popular alternative to conventional treatment methods, however, the metal attenuation processes of these systems are poorly understood. Precipitates from biotic and abiotic zones of a staged constructed wetland treating high metal load (approx. equal to 1000 mg L (super -1) ) and low pH (approx. 3.0) acid mine drainage were characterized by chemical dissolution, x-ray diffraction, thermal analysis and scanning electron microscopy. Characterization of abiotic/aerobic zones within the treatment system suggest the presence of crystalline iron oxides and hydroxides such as hematite, lepidocrocite, goethite, and jarosite. At the air/water interface of initial abiotic treatment zones, SO (sub 4) /Fe ratios were low enough (<2.0) for the formation of jarosite and goethite, but as the ratio increased due to treatment and subsequent reductions in iron concentration, jarosite was transformed to other Fe-oxyhydroxysulfates and goethite formation was inhibited. In addition, elevated pH conditions occurring in the later stages of treatment promoted the formation of amorphous iron oxyhydroxides. Biotic wetland cell substrate characterizations suggest the presence of amorphous iron minerals such as ferrihydrite and Fe(OH) (sub 3) . Apparently, high Fe (super 3+) activity, low Eh and low oxygen diffusion rates in the anaerobic subsurface environment inhibit the kinetics of crystalline iron precipitation. Some goethite, lepidocrocite and hematite, however, were observed near the surface in biotic areas and are most likely attributable to increased oxygen levels from surface aeration and/or oxygen transport by plant roots. Alkalinity generation from limestone dissolution within the substrate and bacterially mediated sulfate reduction also has a significant role on the mineral retention process. The formation of gypsum, rhodochrocite and siderite are by-products of alkalinity generating reactions in this system and may have an impact on S, Mn, and Fe solubility controls. Moreover, the buffering of acidity through excess alkalinity appears to facilitate the precipitation and retention of metals within the system.
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Publisher AAPG Bulletin Place of Publication 81 Editor (up)
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Notes Aerobic and anaerobic metal attenuation processes in a constructed wetland treating acid mine drainage; GeoRef; English; 1997-067790; AAPG Eastern Section and the Society for Organic Petrology joint meeting, Lexington, KY, United States, Sep. 27-30, 1997 Approved no
Call Number CBU @ c.wolke @ 16630 Serial 70
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Author Ye, Z.H.; Whiting, S.N.; Qian, J.H.; Lytle, C.M.; Lin, Z.Q.; Terry, N.
Title Trace element removal from coal ash leachate by a 10-year-old constructed wetland Type Journal Article
Year 2001 Publication J. Environ. Qual. Abbreviated Journal
Volume 30 Issue 5 Pages 1710-1719
Keywords acid mine drainage; Alabama; ash; bioaccumulation; boron; cadmium; constructed wetlands; environmental analysis; environmental effects; iron; Jackson County Alabama; Juncus effusus; leachate; manganese; metals; pH; pollutants; pollution; remediation; soils; sulfur; trace elements; Typha latifolia; United States; vegetation; waste water; wetlands; Widows Creek; Widows Creek Steam Plant; zinc; Typha; Juncus 22, Environmental geology
Abstract This study investigated the ability of a 10-yr-old constructed wetland to treat metal-contaminated leachate emanating from a coal ash pile at the Widows Creek electric utility, Alabama (USA). The two vegetated cells, which were dominated by cattail (Typha latifolia L.) and soft rush (Juncus effusus L.), were very effective at removing Fe and Cd from the wastewater, but less efficient for Zn, S, B, and Mn. The concentrations were decreased by up to 99% for Fe, 91% for Cd, 63% for Zn, 61% for S, 58% for Mn, and 50% for B. Higher pH levels (>6) in standing water substantially improved the removing efficiency of the wetland for Mn only. The belowground tissues of both cattail and soft rush had high concentrations of all elements; only for Mn, however, did the concentration in the shoots exceed those in the belowground tissues. The concentrations of trace elements in fallen litter were higher than in the living shoots, but lower than in the belowground tissues. ne trace element accumulation in the plants accounted for less than 2.5% of the annual loading of each trace element into the wetland. The sediments were the primary sinks for the elements removed from the wastewater. Except for Mn, the concentrations of trace elements in the upper layer (0-5 cm) of the sediment profile tended to be higher than the lower layers (5-10 and 10-15 cm). We conclude that constructed wetlands are still able to efficiently remove metals in the long term (i.e., >10 yr after construction).
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ISSN 0047-2425 ISBN Medium
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Notes Aug 1; Trace element removal from coal ash leachate by a 10-year-old constructed wetland; 2002-017274; References: 33; illus. incl. 2 tables United States (USA); file:///C:/Dokumente%20und%20Einstellungen/Stefan/Eigene%20Dateien/Artikel/5703.pdf; GeoRef; English Approved no
Call Number CBU @ c.wolke @ 5703 Serial 76
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