- Case Studies: Overcoming Persistent Contaminant Rebound Using Adsorptive Technologies
In the past, Vertex has observed how injecting Activated Carbon (AC)-based amendments can be used to provide a quick, effective and sustained treatment for chlorinated solvents, hydrocarbons and other contaminants in a matter of weeks. Previously the use of AC in the subsurface was limited due to the finite adsorptive capacity of the AC emplaced. New technologies allow for both adsorption and subsequent treatment of organic contaminants using efficient modalities. Solvents are treated via the well known chemical reduction pathway. Hydrocarbons are treated via anaerobic biodegradation, which provides a more efficient and sustained treatment compared to aerobic biodegradation. As contaminants are degraded, adsorption sites on the AC once again become accessible to quickly adsorb more contamination from the groundwater, thus overcoming the “rebound” problem.
- Case Study: How to Avoid Failure in the Design and Installation of Permeable Reactive Barriers
This talk will showcase innovative and recent advances in the science and technology behind the design and installation of zero-valent iron permeable reactive barriers (PRB) using a real-world case study. Project components to be profiled include:
• Data review and gap analysis for the site;
• Bench-scale proof-of-concept treatability testing;
• Preliminary full-scale design incorporating computer modeling and sensitivity analysis;
• Physical profiling of the PRB alignment at the site using the in-situ Hydraulic Profiling Tool;
• Updated and final detailed design for the full-scale PRB;
• Installation of the “funnel and gate” RB using a biopolymer slurry for excavation support;
• On-site QA/QC testing of the reactive media and emplacement methodology; and
• Follow-up performance monitoring of treatment effectiveness.
- Rehabilitation of Soils and Groundwater Contaminated with Chlorinated Solvents - Case Study
Perchlorethylene (PCE) is a chlorinated solvent commonly used in the dry cleaning industry. Significant PCE contamination has been identified in a site in the Greater Montreal Area.
Enutech has been mandated to carry out the necessary in situ rehabilitation work. The difficulty of rehabilitation was that the contamination was deep. The contaminated groundwater plume had a length of more than 200 meters and 3100 kg of pure PCE was spilled into the site soils. Contaminants in soils and groundwater were PCE, TCE, DCE. The soil contamination was under a parking lot and covered an area of 550 square meters.
Injection series of a biogeochemical formulation - developed specifically by Enutech's R & D department - were carried out in the site soils to create optimal conditions for the reductive dechlorination reaction of PCE.
- Biogeochemical Treatment of CVOCs
Biogeochemical treatment of cVOCs has been emerging over the last decade. This process offers the promise of introducing aqueous phase reagents that react with each other in the subsurface to form reactive iron sulfides. These solid state iron-sulfides tend to create small mineral deposits with a very large surface area along the in situ flow paths. These solid state iron sulfides have the potential to persist for an extended period of time, reacting with most common cVOCs such as perchloroethylene, trichloroethylene, carbon tetrachloride and other reducable compounds. This presentation will introduce the concepts necessary to create biogeochemical conditions and provide case studies where it was used.