California Department of Toxic Substances Control, 247 pp, 2018

Following the removal of a tank of heating oil (Bunker C) in November 2008, free product was observed in the soil at 20-28 ft bgs. Free product removal was conducted using vacuum trucks, bailers, submersible pumps, absorbent socks, and a heat-enhanced surfactant flushing pilot test (July 2016). The flushing technology is referred to as Chemical Enhanced Oil-Phase Recovery, which encompasses flushing modifications such as surfactant chemistry, alkaline modification, shear-thinning polymer, and thermal enhancement. The nature of the Bunker C oil (viscosity, stickiness, and slow migration) makes it extremely difficult to remove. Prior to the pilot test, manual and vacuum truck methods removed ~69 gal of free product at an estimated cost of $540/gal over 7 years. The pilot removed an additional 23 gal at a cost of ~$10,900/gal (total $250,000), demonstrating that the site lithology severely challenged surfactant flushing efficacy. The highest insoluble product hydrocarbon (PHC) recovered was ~14 g of PHC/L-extracted liquids. Based on the estimated residual mass of 23-212 gal the potential cost of additional free product extraction could range from $250,000 to $2,250,000. The pilot study's preparation, implementation, and results are discussed in Appendix C (PDF pages 78-162) of this report. http://www.envirostor.dtsc.ca.gov/public/view_document.asp?docurl=/public/community_involvement/4010319352/2018%2002%2014%20RAW%20Draft%2DFinal%2Epdf See more information on this cleanup site at http://www.envirostor.dtsc.ca.gov/public/profile_report?global_id=60002158.