Combined approach to remediate chlorinated solvents in Cambridge, UK

Case study highlights:

• The ISCR, bioaugmentation and biostimulation approach was used to optimize the remedial approach by combining wide radii of influence to minimize the number of injection points required, rapid onset of ERD, minimisation of daughter product creation, and long-term treatment from a single application.
• The application took only one day, with remediation occurring in situ, allowing the site development to continue unimpeded.

This site is currently undergoing redevelopment from a former industrial estate and trade park, into a business park. The underlying groundwater is impacted with chlorinated solvents from an adjacent industrial site. REGENESIS provided an in-situ approach that could provide full reductive dichlorination of the contamination from a single injection, allowing redevelopment to occur during the remediation period. It was decided that a combination of In Situ Chemical Reduction (ISCR) using Chemical Reducing Solution (CRS) and Enhanced Reductive Dechlorination (ERD) using 3-D Microemulsion (3DME) as well as bioaugmentation with Bio-Dechlor Inoculum Plus (BDI+) would be applied at this site. This combined approach was designed to provide rapid contaminant degradation, minimized daughter product creation and long-term treatment from the single injection. The treatment used seven direct push injection points to accurately target the contamination in a heterogeneous gravels, sands and clay.