Summary of Tools & Methods to Support the Optimisation & Termination of Active Remediation Systems

Sustainable remediation, natural attenuation, and “nature-based” remediation have emerged as key considerations in remedial decision making at petroleum release sites impacted by light non-aqueous phase liquids (LNAPL). Within this context, a new compendium of tools and methods to support the selection, optimisation and termination of active remediation systems has been developed that is intended to improve remedial decision making. The compendium roadmap consists of four stages: 1: Risk Evaluation and Identification; 2: Baseline Assessment; Stage 3: Remedy Selection and Implementation; 4: Performance Evaluation, Optimisation & Transition Assessment. A baseline assessment of natural attenuation rates (or natural source zone depletion (NSZD)) is a critical step used to inform the selection of remedial system; benchmark rates of LNAPL depletion or COC attenuation under active remediation; and estimate timelines for natural and enhanced depletion. Technology-specific remedial objectives, performance metrics and transition thresholds are provided in four factsheets on NSZD, soil vapor extraction (SVE), bioventing and hydraulic recovery.  Application of the compendium and technology factsheets is expected to minimize unnecessary active remediation, thus helping reduce cost, improved sustainability through lower carbon footprints, and allow limited resources to focus on sites posing the greatest risk.  This project is being conducted for Shell Global (Dr. Matthew Lahvis) together with ARIS Environmental Ltd. (Dr. Parisa Jourabchi). 

Dr. Ian Hers, as Principal and Founder of Hers Environmental Consulting, Inc., has over 30 years experience in soil vapour intrusion characterization and mitigation, assessment of natural attenuation and natural source zone depletion, LNAPL management, fate and transport modelling and sustainable remediation approaches. Dr. Hers has a deep knowledge of soil vapour intrusion and has assisted clients worldwide throughout his career in developing guidance, models and methods. He has published over 25 technical papers and guidance documents on vapour intrusion. He also has outstanding experience in assessment of natural attenuation of chemicals and management of LNAPL contamination and has supported private and public clients in development of guidance and protocols in these areas. He has conducted numerous applied R&D projects and supported developed of guidance worldwide for regulatory agencies in Canada, US, UK and Israel, for organizations such as American Petroleum Institute and Electric Power Research Institute, and oil and gas clients. Dr. Hers holds a Ph.D. from the University of British Columbia (UBC) and has served as lecturer at UBC and the BC Institute of Technology. He has participated on numerous Interstate Technology and Regulatory Council (ITRC) teams.