Significant Project Features:
- Permeable Reactive Barrier (PRB) Installation by the Bio-Polymer Slurry Trench Method
- Installation of Two PRB Trenches
- Sand/Zero Valent Iron Backfill Mixture
- Backfill Mixed Onsite
- Demo of existing Air-Sparge/SVE System
Background:
The site, located in Rochester, Michigan, was originally used for industrial processes related to the automotive industry. Following the closing and demolition of the facility, an Air Sparge/Soil Vapor Extraction (AS/SVE) system was installed to remediate the plume of chlorinated solvents left behind. The plume began slowly migrating off-site and the existing AS/SVE system was no longer effective in the remediation of the contaminants.
Project Objectives:
- Intercept the plumes of migrating Chlorinated Solvents
- Treat In-Situ using Permeable Reactive Barrier (PRB) Technology
- Perform required demolition, restoration, and site work to convert the site into a public recreation area (park).
Description of Work:
Geo-Solutions installed two PRB Trenches Totaling over 8,000 Square Feet. The trenches were installed by the Bio-Polymer (BP) Slurry Trench Method and were up to 34-feet deep. This method has been used extensively since Geo-Solutions installed the first BP PRB trench in 1999.
The trench backfill was a mixture of granular Zero-Valent Iron and Sand. Backfill was mixed onsite using a mobile concrete mixer and tremied in place.
All trench spoils were disposed off-site in an appropriate landfill facility. The trench was clay-capped and a series of monitoring wells were installed for long-term observation and measurement.
Geo-Solutions also demolished and disposed of the existing AS/SVE system as well as all remnant footers and slabs from the original facility. The site was graded; topsoil cover was placed and the site was seeded and planted.
Project Challenges:
Due to the site contaminants, the project was designated HAZ and subject to OSHA 1910.120. The work was performed in an urban setting, in a moderately busy section of town. Site control, real-time air monitoring, and safe construction practices were paramount to protect both Geo-Solutions’ workers as well as the public. The project was completed on time and with zero health and safety related incidents.
