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Kleinmann, R. L. P. (1990). Acid Mine Water Treatment using Engineered Wetlands. Int. J. Mine Water, 9(1-4), 269–276.
Abstract: 400 systems installed within 4 years During the last two decades, the United States mining industry has greatly increased the amount it spends on pollution control. The application of biotechnology to mine water can reduce the industry's water treatment costs (estimated at over a million dollars a day) and improve water quality in streams and rivers adversely affected by acidic mine water draining from abandoned mines. Biological treatment of mine waste water is typically conducted in a series of small excavated ponds that resemble, in a superficial way, a small marsh area. The ponds are engineered to first facilitate bacterial oxidation of iron; ideally, the water then flows through a composted organic substrate that supports a population of sulfate-reducing bacteria. The latter process raises the pH. During the past four years, over 400 wetland water treatment systems have been built on mined lands as a result of research by the U.S. Bureau of Mines. In general, mine operators find that the wetlands reduce chemical treatment costs enough to repay the cost of wetland construction in less than a year. Actual rates of iron removal at field sites have been used to develop empirical sizing criteria based on iron loading and pH. If the pH is 6 or above, the wetland area (in2) required is equivalent to the iron. load (grams/day) divided by 10. Theis requirement doubles at a pH of 4 to 5. At a pH below 4, the iron load (grams/day) should be divided by 2 to estimate the area required (in2).
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Jage, C. R., & Zipper, C. E. (2000). Acid-mine drainage treatment using successive alkalinity-producing systems. Powell River Project research and education program reports.
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Amacher, M. C., Brown, R. W., Kotuby-Amacher, J., & Willis, A. (1993). Adding sodium hydroxide to study metal removal in a stream affected by acid mine drainage. Research Paper, US Department of Agriculture, Forest Service, 465(17).
Abstract: Fisher Creek, a stream affected by acid mine drainage in the Beartooth Mountains of Montana, was studied to determine the extent to which copper (Cu) and zinc (Zn) would be removed from stream water when pH was increased by a pulse of sodium hydroxide (NaOH). Although the pH adjustment study indicated that precipitated Fe(OH) “SUB 3” (am) could rapidly remove Cu and Zn from a stream affected by acid mine drainage, the pH should be maintained in an optimal range (7 to 8.5) to maximize removal by adsorption. -from Authors
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Lin, C., Lu, W., & Wu, Y. (2005). Agricultural soils irrigated with acidic mine water: Acidity, heavy metals, and crop contamination. Australian Journal of Soil Research, 43(7), 819–826.
Abstract: Agricultural soils irrigated with acidic mine water from the Guangdong Dabaoshan Mine, China, were investigated. The pH of the soils could be as low as 3.9. However, most of the mineral acids introduced into the soils by irrigation were transformed to insoluble forms through acid buffering processes and thus temporarily stored in the soils. Different heavy metals exhibited different fraction distribution patterns, with Zn and Cu being mainly associated with organic matter and Pb being primarily bound to oxides (statistically significant at P = 0.05). Although the mean of exchangeable Cd was greatest among the Cd fractions, there was no statistically significant difference between the exchangeable Cd and the oxide-bound Cd (the 2nd greatest fraction) or between the exchangeable Cd and the carbonate-bound Cd (the 3rd greatest fraction). It was also found that there were generally good relationships between the concentrations of various Zn, Cu, Pb, and Cd fractions and pH, suggesting that a major proportion of each heavy metal in the soils was mainly derived from the acidic irrigation water. The results also show that the crops grown in these soils were highly contaminated by heavy metals, particularly Cd. The concentration of Cd in the edible portions of most crops was far in excess of the limits set in China National Standards for Vegetables and Fruits and this can be attributable to the extremely high transfer rate of Cd from the soils to the crops under the cropping system adopted in the study area. < copyright > CSIRO 2005.
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Ntengwe, F. W. (2005). An overview of industrial wastewater treatment and analysis as means of preventing pollution of surface and underground water bodies – The case of Nkana Mine in Zambia. Phys. Chem. Earth, 30(11-16 Spec. Iss.), 726–734.
Abstract: The wastewaters coming from mining operations usually have low pH (acidic) values and high levels of metal pollutants depending on the type of metals being extracted. If unchecked, the acidity and metals will have an impact on the surface water. The organisms and plants can adversely be affected and this renders both surface and underground water unsuitable for use by the communities. The installation of a treatment plant that can handle the wastewaters so that pH and levels of pollutants are reduced to acceptable levels provides a solution to the prevention of polluting surface and underground waters and damage to ecosystems both in water and surrounding soils. The samples were collected at five points and analyzed for acidity, total suspended solids, and metals. It was found that the pH fluctuated between pH 2 when neutralization was forgotten and pH 11 when neutralization took place. The levels of metals that could cause impacts to the water ecosystem were found to be high when the pH was low. High levels of metals interfere with multiplication of microorganisms, which help in the natural purification of water in stream and river bodies. The fish and hyacinth placed in water at the two extremes of pH 2 and pH 11 could not survive indicating that wastewaters from mining areas should be adequately treated and neutralized to pH range 6-9 if life in natural waters is to be sustained. < copyright > 2005 Elsevier Ltd. All rights reserved.
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