Combined alcohol and viscous polymer flooding for enhanced removal of polychlorinated biphenyls from fractured rock.

摘要

The use of an aggressive in-situ flushing technology to remove and capture potentially mobile dense non-aqueous phase liquid (DNAPL) contained in fractured bedrock was assessed in the laboratory. Preliminary phase behaviour experiments involving PCB (polychlorinated biphenyls)/alcohol/water systems were conducted with two short-chained alcohols: ethanol (EtOH) or n-propanol (nPA). Both exhibited affinity for the aqueous phase within the entire two-phase region. The interfacial tension (IFT) dropped from 38.9 dynes/cm between PCB and water to 4.7 dynes/cm and to 2.4 dynes/cm with 80%/vol. EtOH and 76%/vol. nPA in the aqueous phase, respectively. The addition of alcohol also caused a 41% and 54% reduction in the viscosity of the DNAPL at maximal concentrations of EtOH and nPA, respectively.; A series of seven experiments were conducted where successive slugs of nPA and xanthan gum polymer solutions were injected in a fractured rock sample. The effect of the alcohol flood size, alcohol slug concentration and hydraulic gradient on PCB removal effectiveness was investigated. (Abstract shortened by UMI.)