@article{BalckeHahnOswald2011,
  author    = {Balcke, Gerd U. and Hahn, M. and Oswald, Sascha Eric},
  title     = {Nitrogen as an indicator of mass transfer during in-situ gas sparging},
  series = {Journal of contaminant hydrology},
  volume    = {126},
  journal   = {Journal of contaminant hydrology},
  number    = {1-2},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {0169-7722},
  doi       = {10.1016/j.jconhyd.2011.05.005},
  pages     = {8 -- 18},
  year      = {2011},
  abstract  = {Aiming at the stimulation of intrinsic microbial activity, pulses of pure oxygen or pressurized air were recurrently injected into groundwater polluted with chlorobenzene. To achieve well-controlled conditions and intensive sampling, a large, vertical underground tank was filled with the local unconfined sandy aquifer material. In the course of two individual gas injections, one using pure oxygen and one using pressurized air, the mass transfer of individual gas species between trapped gas phase and groundwater was studied. Field data on the dissolved gas composition in the groundwater were combined with a kinetic model on gas dissolution and transport in porous media. Phase mass transfer of individual gas components caused a temporary enrichment of nitrogen, and to a lower degree of methane, in trapped gas leading to the formation of excess dissolved nitrogen levels downgradient from the dissolving gas phase. By applying a novel gas sampling method for dissolved gases in groundwater it was shown that dissolved nitrogen can be used as a partitioning tracer to indicate complete gas dissolution in porous media.},
  language  = {en}
}
@article{BuschMeissnerPotthoffetal.2015,
  author    = {Busch, Jan Philip and Meißner, Tobias and Potthoff, Annegret and Bleyl, Steffen and Georgi, Anett and Mackenzie, Katrin and Trabitzsch, Ralf and Werban, Ulrike and Oswald, Sascha Eric},
  title     = {A field investigation on transport of carbon-supported nanoscale zero-valent iron (nZVI) in groundwater},
  series = {Journal of contaminant hydrology},
  volume    = {181},
  journal   = {Journal of contaminant hydrology},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {0169-7722},
  doi       = {10.1016/j.jconhyd.2015.03.009},
  pages     = {59 -- 68},
  year      = {2015},
  abstract  = {The application of nanoscale zero-valent iron (nZVI) for subsurface remediation of groundwater contaminants is a promising new technology, which can be understood as alternative to the permeable reactive barrier technique using granular iron. Dechlorination of organic contaminants by zero-valent iron seems promising. Currently, one limitation to widespread deployment is the fast agglomeration and sedimentation of nZVI in colloidal suspensions, even more so when in soils and sediments, which limits the applicability for the treatment of sources and plumes of contamination. Colloid-supported nZVI shows promising characteristics to overcome these limitations. Mobility of Carbo-Iron Colloids (CIC) - a newly developed composite material based on finely ground activated carbon as a carrier for nZVI - was tested in a field application: In this study, a horizontal dipole flow field was established between two wells separated by 53 m in a confined, natural aquifer. The injection/extraction rate was 500 L/h. Approximately 12 kg of CIC was suspended with the polyanionic stabilizer carboxymethyl cellulose. The suspension was introduced into the aquifer at the injection well. Breakthrough of CIC was observed visually and based on total particle and iron concentrations detected in samples from the extraction well. Filtration of water samples revealed a particle breakthrough of about 12\% of the amount introduced. This demonstrates high mobility of CIC particles and we suggest that nZVI carried on CIC can be used for contaminant plume remediation by in-situ formation of reactive barriers. (C) 2015 Elsevier B.V. All rights reserved.},
  language  = {en}
}