The client faced a complex challenge. Despite a Pump & Treat system that had been operating for years, there was still no clear understanding of the exact source zone, the vertical distribution of contamination or its behaviour in the subsurface. This uncertainty limited remediation efficiency and delayed further optimisation.
Identification of source zone(s)
The assignment was clear: map the subsurface at high resolution, identify the source zone(s) and deliver insights to refine the existing remediation system. The site remained fully operational throughout, meaning every intervention had to be fast, compact and highly accurate.
HRSC with MIP and HPT
We carried out an integrated High-Resolution Site Characterisation (HRSC) campaign using two complementary tools:
- EnISSA-MIP
Real-time detection of BTEX, mineral oils and cVOCs across the full depth profile; - HPT
Measurement of permeability and pressure response to identify hydrogeological barriers and preferential flow paths.
Together, these methods provided a single, coherent picture of subsurface chemistry and geology, essential for understanding contaminant behaviour.
Investigation results
- A clearly defined source zone containing BTEX, mineral oils and cVOCs;
- Accumulation of contamination just above the first low-permeability layer at approximately 4 m depth;
- A second concentration zone around 10 m depth, previously unidentified;
- A detailed contaminant distribution model, linked to local geological structures.
These insights delivered the missing pieces needed to optimise control of the Pump & Treat system.
Our service to the client
- The full HRSC campaign was executed without any impact on ongoing production;
- We provided immediately actionable advice on flow rate optimisation, source-zone treatment and monitoring strategy;
- Uncertainty was significantly reduced in a single campaign, eliminating the need for additional investigations;
- We delivered a robust, evidence-based decision framework for the next remediation phase.
With one high-resolution campaign, the client now has a complete and reliable subsurface model, ready to fine-tune the remediation strategy faster, more efficiently and with greater confidence.