Transport Model Of Fluids Injected In A Landfill Polluted With Lindane Wastes

Dense non-aqueous phase liquids (DNAPLs) are ubiquitous environmental problem causing contamination of soil and groundwater. The remediation strategies, such us in situ chemical oxidation (ISCO), need a good preliminary characterization of injected chemicals transport within the subsoil in order to select an adequate injection-extraction strategy and calculate both the chemical dosage and the contact time required.In this work, the flow was studied in a polluted site located in Sabinanigo (Spain) where a DNAPL generated by lindane production process was dumped as production waste. The flow was studied using a tracer step experiment injecting a constant flow rate of tap water with bromide. Analysis of the groundwater samples composition of tracer with time obtained was accomplished at several monitoring wells being used to propose a transport model, which was implemented in gPROMS. The experimental data were used to fit a dispersion coefficient to depend on the velocity of the fluid. The transport model was validated with a second step tracer experiment, carried out at lower flowrate. Besides, the transport model obtained has been used to predict the oxidant (persulfate) concentration profiles from the injection point, considering different flow rates in an ISCO treatment.