In Situ Pilot Test

STAR – New Jersey Field Trial

Gerhard, in collaboration with SiREM/Geosyntec and DuPont, is conducting a phased pilot test of in situ coal tar destruction at the Pitt Consul site in New Jersey, USA. This cresol manufacturing site from the late 1800s, and acquired by DuPont in 1998, exhibits extensive coal tar contamination between 1.5m and 3m below ground surface.  In September 2009, a single well test demonstrated that, after a short ignition of several hours, self-sustained smouldering was continued for 9 days below the water table.  Carbon balance on the emissions indicates that approximately 240 kg of coal tar was destroyed during the test. Phase II targeted a 7m wide by 18m long pilot test area (PTA) enclosed by sheet piling that exhibited high saturation coal tar below the water table.  9 ignition/air injection wells were installed and a complete gas capture/treatment system employed. During the 12 days of self-sustaining treatment, more than 4500 kg of coal tar was destroyed, with destruction rates as high at 800 kg/day. The front propagated up to 12 m from a single ignition well and treated coal tar over the full 1.5 m target depth interval. An average reduction in Total Petroleum Hydrocarbon concentration of 99.72% was observed in post-treatment soil cores. Phase III is now proceeding in order to upscale the approach for treating a larger, uncontained portion of the site.

In situ STAR pilot test showing soil cores before (left) and after (right) treatment

Ex Situ Reactor