Project

Removal of predominantly creosote contamination from a former timber treatment facility.

Steam Enhanced Remediation (SER), Free Product pumping, Dual Phase Vacuum Extraction (DPVE) and Air Sparge (AS) targeting remediation of Dense Non-Aqueous Phase Liquids (DNAPL) and Semi-Volatile impacted groundwater and soils.

Challenges

The remediation objectives required the complete removal of DNAPL and betterment of contaminant concentrations in both soils and groundwater. The maximum DNAPL thickness was 700mm. During the installation phase it was evident that the plume area was larger than expected, the area increased from 600m² to 1100m². The flexibility of the equipment allowed the treatment area and remediation system to be redesigned accordingly.

Churngold Solution

The SER system was bespoke built, comprising steam generation & injection systems. Over forty-five wells were available for Steam injection, which could also be used for AS or DNAPL pumping. Twelve wells were available for DPVE.

High temperatures were recorded after only one week of SER, the temperature increased throughout the heating period as steam injection was intermittently pulsed in different areas of the site to target hot spot zones.

The treatment resulted in subsurface temperature increasing from an average of 90^oC to 59^oC. Heavily impacted areas were heated to >95^oC to allow Hydro Pyrolysis Oxidation, a process where oxygen becomes a powerful chemical oxidant at temperatures greater than 90^oC.

DNAPL pumps and DPVE were used to remove the mobilised Free Product. A total of over 4500kg was removed.

Current Status

The remediation was undertaken over a 7-month period removing free product from all wells. The project was also completed on programme and successfully validated over a 4 month period by a third party consultant.