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Calabrese, J. P., Sexstone, A. J., Bhumbla, D. K., Skousen, J. G., Bissonnette, G. K., & Sencindiver, J. C. (1994). Long-term study of constructed model wetlands for treatment of acid mine drainage. In Special Publication – United States. Bureau of Mines, Report: BUMINES-SP-06B-94 (406). Proceedings of the International land reclamation and mine drainage conference and Third international conference on The abatement of acidic drainage; Volume 2 of 4; Mine drainage.
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Davis, L. K. (1994). Constructed wetlands handbook. In Special Publication – United States. Bureau of Mines, Report: BUMINES-SP-06B-94 (409). Proceedings of the International land reclamation and mine drainage conference and Third international conference on The abatement of acidic drainage; Volume 2 of 4; Mine drainage.
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Demchak, J., Morrow, T., Skousen, J., Donovan, J. J., & Rose, A. W. (2001). Treatment of acid mine drainage by four vertical flow wetlands in Pennsylvania Evolution and remediation of acid-sulfate groundwater systems at reclaimed mine-sites. Geochemistry – Exploration, Environment, Analysis, 1(1), 71–80.
Abstract: Acid mine drainage (AMD) is a serious problem in many watersheds where coal is mined. Passive treatments, such as wetlands and anoxic limestone drains (ALDs), have been developed, but these technologies show varying treatment efficiencies. A new passive treatment technique is a vertical flow wetland or successive alkalinity producing system (SAPS). Four SAPS in Pennsylvania were studied to determine changes in water chemistry from inflow to outflow. The Howe Bridge SAPS removed about 130 mg l (super -1) (40%) of the inflow acidity concentration and about 100 mg l (super -1) (60%) iron (Fe). The Filson 1 SAPS removed 68 mg l (super -1) (26%) acidity, 20 mg l (super -1) (83%) Fe and 6 mg l (super -1) (35%) aluminium (Al). The Sommerville SAPS removed 112 mg l (super -1) (31%) acidity, exported Fe, and removed 13 mg l (super -1) (30%) Al. The McKinley SAPS removed 54 mg l (super -1) (91%) acidity and 5 mg l (super -1) (90%) Fe. Acid removal rates at our four sites were 17 (HB), 52 (Filson1), 18 (Sommerville) and 11 (McKinley) g of acid per m (super 2) of surface wetland area per day (g/m (super 2) d (super -1) ). Calcium (Ca) concentrations in the SAPS effluents were increased between 8 and 57 mg l (super -1) at these sites. Equilibrators, which were inserted into compost layers to evaluate redox conditions at our sites, showed that reducing conditions were generally found at 60 cm compost depths and oxidized conditions were found at 30 cm compost depths. Deeply oxidized zones substantiated observations that channel flow was occurring through some parts of the compost. The Howe Bridge site has not declined in treatment efficiency over a six year treatment life. The SAPS construction costs were equal to about seven years of NaOH chemical treatment costs and 30 years of lime treatment costs. So, if the SAPS treatment longevity is seven years or greater and comparable effluent water quality was achieved, the SAPS construction was cost effective compared to NaOH chemical treatment. Construction recommendations for SAPS include a minimum of 50 cm of compost thickness, periodic replacement or addition of fresh compost material, and increasing the number of drainage pipes underlying the limestone.
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Demin, O. A., Dudeney, A. W. L., & Tarasova, I. I. (2002). Remediation of Ammonia-rich Minewater in Constructed Wetlands. Environ. Technol., 23(5), 497–514.
Abstract: A three-year study of ammonia removal from minewater was carried out employing constructed wetland systems (surface flow wetland and subsurface flow wetland cells) at the former Woolley Mine in West Yorkshire, UK The 1.4 Ha surface flow wetland (constructed in 1995) reduced the ammonia concentration from 3.5 – 4.5 mg l(-1) to < 2 3 mg V during the first half of the study and to essentially zero in the last year (2000 – 2001). About 25 % of contained ammonia was converted to nitrate, about 10 % was consumed by the plants and up to 30 % was converted to nitrogen gas. This maturation effect was attributed to increased depth of sludge from sedimentation of ochre, providing increased surface area for immobilisation of ammonia oxidising bacteria. The surface flow wetland finally removed 23 g m(-2) day(-1) ammonia in comparison with 3.8 g m(-2) day' for the subsurface flow (pea gravel) wetland cells, constructed for the present work and dosed with ammonium salts. Removal of ammonia by both systems was consistent with well-established mechanisms of nitrification and denitrification. It was also consistent with ammonia removal in wastewater wetland systems, although the greater aeration in the minewater systems obviated the need for special aeration cycles. The general role of wetland plants in such aerated conditions was attributed to maintaining hydraulic conditions (such as hydraulic efficiency and hydraulic resistance of substratum in subsurface flow systems) in the wetlands and providing a suspended solids filter for minewater.
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Dempsey, B. A., & Jeon, B. - H. (2001). Characteristics of sludge produced from passive treatment of mine drainage. Geochem.-Explor. Environ. Anal., 1(1), 89–94.
Abstract: In the 1994 paper by Brown, Skousen & Renton it was argued that settleability and wet-packing density were the most important physical characteristics of sludge from treatment of mine drainage. These characteristics plus zeta-potential, intrinsic viscosity, specific resistance to filtration, and coefficient of compressibility were determined for several sludge samples from passive treatment sites and for several sludge samples that were prepared in the laboratory. Sludge from passive systems had high packing density, low intrinsic viscosity, low specific resistance to filtration and low coefficient of compressibility compared to sludge that was produced after addition of NaOH.
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