Measurement of individual compounds

with detection limits up to ppb level


EnISSA Membrane Interface probe

Accurate soil investigations and their sampling programs are a critical component of reliable, efficient and cost-effective cleanup processes.

Traditional sampling methods are characterized by low detection levels and a broad analysis spectrum. However delineation of the contaminated area by traditional sampling methods is not only a time and cost consuming task but also parts of the contaminated area could be overlooked.

“On site” soil characterization technologies such as the MIP and ROST techniques are already frequently applied to obtain additional information which cannot be obtained by traditional sampling methods. Although conventional MIP has proven its use in source zones survey, the characterization of plumes is difficult due to the rather high detection limits of the conventional detectors (PID, ECD, FID). Detection limits are highly dependent on membrane temperature, detector maintenance, operator experience, ...  (Bodem 3, 2008). A recent article (J. Soil Sediments 9:74-82 (2009)) mentions detection limits  of 3000-10000 ug/l. Due to modifications of the detectors which cause less background noise, some providers can detect concentrations in optimal conditions down to ca. 200 - 500 ug/l, but which is still much higher compared to soil clean up values.

Secondly, since the conventional detectors are sum detectors the information obtained by MIP cannot be correlated with soil clean-up reference values which are determined for individual components.

Characterization of Source and Plume

Since individual components are measured well below the soil-cleanup values, both source and plume delineation is possible resulting in highly detailed soil profiles which allow reliable “on site” decisions. Using different push technologies, depth up to 40 m are possible (dependent on geology).
      

FAST IN SITU METHOD

Using the conventional MIP-speed (30 cm/min), each 30 cm a full characterisation of the pollution is possible on ug/l level using the EnISSA method.

Reduced sampling costs and time

Time inefficient and cost consuming classic sampling methods are still needed for the characterization, confirmation and the delineation of the entire contaminated area when using conventional MIP. EnISSA MIP measures both source and plume making it possible to place sampling wells at strategic locations and reducing sampling costs and time. Costs for the EnISSA MIP are comparable to qualitative conventional MIP.

Instant site characterisation, Analysis & Remediation

Based on the high resolution depth profiles for individual contaminants, target injections with optimised reagent requirements can be performed. The interaction between Instant site characterisation, analysis & remediation (ISCAR) leads to an improved remedial action resulting in a reduced consumption of reagents but without loss of performance due to a better balance between contaminant and injection reagents.


The EnISSA method uses a GCMS system which is connected to the MIP by an innovative gas sampling system. A highly improved analysis method results in cycle times of 1 min.

Using this technique, individual components can be characterised with detection limits around or below 10 ug/l. The combination of smart method optimisation and innovative gas sampling is unique and makes it possible to qualify and quantify pollutant cocktails within the time frame of conventional MIP.


This project is possible thanks to the financial support of the Flemish institute for Science and Technology (IWT)