Prescreening Services


E-Flux strives to help each customer get the most out of their Fossil Fuel Traps. This requires a good conceptual site model and knowledge of LNAPL extent and behavior before deployment. Although the Fossil Fuel Traps offer high-quality results, gathering additional site data is useful for determining sampling locations and discovering limitations. E-Flux offers additional prescreening tools that help with:

  • Obtaining a high-density data set
  • Achieving quick turnaround
  • Identifying limitations such as seasonal variation and capping layers
  • Finding optimal sampling locations
  • Correlating CO2 fluxes to site conditions

Customized Options

E-Flux offers quotes per unit or we can help you develop a natural source zone depletion package that is customized to fit your unique site conditions and project objectives. Following are descriptions of several options that can be included as needed.

E-Flux Prescreening Tools

Tool Measurement Applicability Advantages Disadvantages
Thermocouples* Temperature (groundwater and/or vadose zone) Find locations with thermal signatures indicating biodegradation; monitor seasonality on temperate sites Measure the vadose zone or groundwater; easy to perform once or install permanently; inexpensive Temperature measurements are subject to noise
Multi-level samplers (requires a gas analyzer) Soil gas concentrations, groundwater concentrations Sample soil gases at different depths for concentrations; sample groundwater to determine extent of LNAPL Sample discrete intervals in the vadose and/or saturated zone; permanent installation allows for many sampling events at the same location Need to install new monitoring wells; more time-consuming than some other methods
Soil gas probe (requires a gas analyzer) Soil gas concentrations Sample many locations and depths across a site to find locations with high soil CO2 concentrations; sample other soil gases (methane and oxygen) for data correlation Quick and easy to sample many locations and depths across a site; obtain a high-density data set in a short amount of time Cannot collect groundwater information
Well headspace sampling † (requires a gas analyzer) Soil gas concentrations Sample the vadose zone of existing monitoring wells to find locations with high soil CO2 concentrations; sample other soil gases (methane and oxygen) for data correlation Utilizes existing monitoring wells; easy to perform Only compares existing monitoring well locations

* Previous work has shown that petroleum biodegradation results in a thermal signature in groundwater (McCoy et al., 2014) and in the vadose zone (Sweeney and Ririe, 2014). (More information.)

This technique was developed by Jewell and Wilson (2011).

References

  • Jewell, K. and J. Wilson. 2011. "A New Screening Method for Methane in Soil Gas Using Existing Groundwater Monitoring Wells". Groundwater Monitoring and Remediation, Vol 31 (3), pp. 82-94
  • McCoy, K., Zimbron, J., Sale, T., & Lyverse, M. 2014. "Measurement of Natural Losses of LNAPL Using Fossil Fuel Traps". Groundwater. doi:10.1111/gwat.12240
  • Sweeney, R. and T. Ririe. 2014. "Temperature as a Tool to Evaluate Aerobic Biodegradation in Hydrocarbon Contaminated Soil". Groundwater Monitoring and Remediation, Vol 34, pp. 41-50