Case Study: In-Situ Formaldehyde Spill Response
During 2012 a transport truck containing 35,000 L of heated waste formaldehyde crashed releasing its contents and diesel fuel to a steep embankment. The steaming waste cascaded to and along a secondary roadway before being released through a culvert and downwards to cottages and ultimately a lake which supplied drinking water to more than 75,000 people. The formaldehyde and/or petroleum hydrocarbon compounds (PHCs) impacted surface soils, surface water, sand and bedrock aquifers, and the local community, elected officials, and Ministry of the Environment all became actively involved.
The purpose of this case study is to present how the spill response was completed with a focus on the careful efforts undertaken once the easily accessible soils were excavated and removed. With formaldehyde concentrations in the sand and bedrock aquifers at greater than 3,000,000 ug/L and 600,000 ug/L, respectively, and with a high degree of public interest, an evaluation of in-situ remedial methods was completed. Due to the unknown behaviour of high dissolved and adsorbed formaldehyde and PHC concentrations in the subsurface, a bench-scale study was completed to assess oxidation treatment effectiveness. Pilot-scale testing was also undertaken using various tracers to assess oxidant delivery, and full-scale in-situ work was completed to remediate the spill and downgradient locations. This talk will present all aspects of the in-situ spill response, including the bench, pilot, and the successful full-scale clean-up.