Theoretical background and application principles of Monitoring Natural Attenuation (MNA) contaminated aquifers not engineered remediation methodology are presented. A detailed knowledge of hydrodinamical, hydrochemical and microbiological processes occurring inside and , particularly, at the interfacial fringe (the so called “corona”) of the plume is put in evidence as the key factor in assessing the natural attenuation potential. Chemical mass balance of plume and identification of chemical “footprints” reflecting that NA is really working are the two most important tools to evaluate the processes. As a representative case study the Rexco plant (Mansfield, UK) is considered. A phenols plume has been almost entirely attenuated by the natural groundwater system avoiding so the contamination of wells located downgradient; at the same time an ammonium plume, originating at the same plant, also if strongly retarded by the finer matrix of the aquifer, has was recalcitrant to attenuation. The presented case study underlines the importance of a combined use of both an experimental verification and a forecasting of the plume time-space evolution by numerical models, being the first one necessary for the calibration and the progressive tuning of the second one.
The use of monitored natural attenuation as a cost effective technique for groundwater restoration: the case study of REXCO (UK)
MASTROCICCO, Micol
2002
Abstract
Theoretical background and application principles of Monitoring Natural Attenuation (MNA) contaminated aquifers not engineered remediation methodology are presented. A detailed knowledge of hydrodinamical, hydrochemical and microbiological processes occurring inside and , particularly, at the interfacial fringe (the so called “corona”) of the plume is put in evidence as the key factor in assessing the natural attenuation potential. Chemical mass balance of plume and identification of chemical “footprints” reflecting that NA is really working are the two most important tools to evaluate the processes. As a representative case study the Rexco plant (Mansfield, UK) is considered. A phenols plume has been almost entirely attenuated by the natural groundwater system avoiding so the contamination of wells located downgradient; at the same time an ammonium plume, originating at the same plant, also if strongly retarded by the finer matrix of the aquifer, has was recalcitrant to attenuation. The presented case study underlines the importance of a combined use of both an experimental verification and a forecasting of the plume time-space evolution by numerical models, being the first one necessary for the calibration and the progressive tuning of the second one.I documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
