One dimensional model of a permeable reactive barrier for the remediation of groundwater polluted by acid mine drainage in mining sites

The current study was conducted to evaluate by mean of a reactive transport model a possible groundwater remediation with the use of PRB technology, in the mining area eastward of Montevecchio, located in the southwestern part of Sardinia, polluted by AMD. Reactive transport modeling represents an excellent tool to analyze and quantify the different reactions and their interactions in multi-component system during advective and dispersive transport. A one dimensional reactive transport model has been developed with the code PHREEQC (Parkhust and Appelo) to assess the efficiency in the short and in the long period of a PRB, composed by organic carbons, used for the treatment of the mine drainage in the specific site of study and to estimate its longevity. The model simulates the dissolved pollutants removal inside the reactive medium, taking into account degradation rates of organic matter, reduction of sulfate, media compositional changes, ion metal concentration, removal mechanisms of sulfates and heavy metals, precipitation-dissolution of reduced mineral phases that precipitate as reduced mineral phases and drop in reactivity due to precipitation of mineral phases and dissolution of organic matter. Four different simulations were performed varying the hydraulic conductivity of the reactive medium, in order to evaluate how the PRB efficiency varies in the short and in the long period, varying the reactive medium characteristics. The simulation results put in evidence the potential of an organic carbon PRB in removing inorganic contaminants contained in acidic leachates, generated at mining sites. The study introduce an application tool that elucidates the geochemical processes that occurs in preventing the contaminants transport in a site of interest by mean of a PRB. It could be an useful tool in the hypothesis of a future PRB installation in the site of Montevecchio to establish its best configuration.

@TechReport{Gir11,
  author       = {Girau, A.},
  title        = {One dimensional model of a permeable reactive barrier for the remediation of groundwater polluted by acid mine drainage in mining sites},
  institution  = {CRS4, Center for Advanced Studies, Research and Development in Sardinia},
  number       = {11/07},
  month        = {may},
  year         = {2011},
  address      = {Cagliari, Italy},
  type         = {techreport},
  keywords     = {Acid mine drainage, Permeable Reactive Barrier, Organic Carbon, Reactive transport model, PHREEQC},
  url          = {https://publications.crs4.it/pubdocs/2011/Gir11},
}