Membrane Interface Probe & MiHptFigure 2

The membrane interface probe (MIP) is a screening tool used to log the relative concentration of volatile organic compounds (VOCs) with depth in soil. The probe is robust and percussion driveable with direct push machines. The MIP membrane is comprised of a semi-permeable, thin film polymer impregnated into a stainless steel screen for support. The membrane is placed in a heated block that is advanced into the soil. With heat, volatiles diffuse across the membrane and partition into a stream of carrier gas where they are swept to the detectors. For VOC detection, a photoionization detector (PID), a flame ionization detector (FID), and a halogen specific detector (XSD) are utilized. This combination enables qualitative and semi-quantitative assessment of the contaminants encountered. The MIP acquisition software logs detector signal with depth.

 

  • Real-time, in-situ detection of volatile organic compounds (halogenated and non-halogenated).
  • Production data provides VOCs discreet spatial delineation, relative concentrations and general speciation.
  • Able to log in saturated and unsaturated materials.
  • Coupled with the Electric Conductivity probe and Hydraulic Profiling Tool (optional) to provide hydrogeological context to contaminant distributions.
  • A leading edge technology utilized worldwide for the characterization and management of petroleum and halogenated hydrocarbons.

The following example log displays HPT injection pressure, pieziometric pressure, estimated hydraulic conductivity, PID, XSD and FID data highlighting the wealth of information collected from a single MiHPT push.

In this instance the MIP data identified a high concentration of chlorinated solvent impacts in the near surface tapering off into the saturated zone (water table identified at 1.75 meters below ground surface). The HPT data displays three distinct hydrostratigraphic units in the saturated zone correlating to sand with inter bedded silt, silty sand, and clay. Together this high resolution information enables the accurate conceptualization of impacts and the hydrogeologic context, greatly improving the efficacy and efficiency of further assessment, remediation and risk management activities.

 

Hydraulic Profiling Tool

hpt-equipment-and-logs

The Hydraulic Profiling Tool (HPT) is a logging tool that measures the pressure required to inject a flow of water into the soil as the probe is advanced into the subsurface. This injection pressure log is an excellent indicator of formation permeability. In addition the HPT can also be used to measure hydrostatic pressure under the zero flow condition. This allows the development of a hydrostatic pressure graph for the log and prediction of the position of the water table. Together, this enables the precise mapping of hydrogeological features and contaminant transport pathways and storage zones.

To learn more about HRSC and how it can help at your impacted site please contact us.

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