ZVI and BGCR-S Direct Push Injection in San Diego County
- toddwhanna
- 1 hour ago
- 2 min read
The Legacy SoCal Team recently completed a ZVI and BGCR‑S slurry direct‑push injection project at a site in San Diego County. For this remediation event, the selected remedy was a mixture of <45‑micron Zero Valent Iron (ZVI) and BioGeoChemical Reduction Solution (BGCR‑S), supplied by CERES Remediation Products. Additionally each injection point was also bioaugmented using SDC‑9 microbial culture.
Due to limited space onsite, and to minimize impacts to the tenants, we tucked everything in as tightly as possible.
As usual, our injection trailer was positioned on a spill berm to maintain proper secondary containment.
The reagent mixture was prepared and pumped from one of our self‑contained injection trailers.
CERES <45‑micron ZVI was supplied in 50‑pound bags. Due to the small work area, we were unable to use our bulk loader and super sacks of ZVI.
Reactive micro‑scale ZVI powder is one of the most effective and well‑proven remediation technologies for achieving successful in situ chemical reduction (ISCR) of chlorinated solvents.
CERES BioGeoChemical Reduction Solution (BGCR‑S) was provided in 55.1‑pound bags.
BGCR‑S is a soluble formulation tailored to stimulate both chemical and microbial reduction reactions in contaminated soil and groundwater.
A small amount of guar gum was added to the mixture to help keep the ZVI powder suspended within the slurry.
Guar gum is a natural, plant‑based thickening agent commonly used to increase viscosity in liquid mixtures. Guar helps maintain a uniform distribution of fine ZVI powder throughout the injection process.
The slurry mixture was prepared in alternating batches in our two onboard mix tanks, ensuring a continuous supply to the piston injection pump.
The ZVI, BGCR‑S, guar, and water mixture forms a moderately thick slurry, which is essential for maintaining proper suspension of the non‑soluble reagents.
The added viscosity provided by the guar helps prevent the fine ZVI particles from settling during mixing, transfer to the pump, and injection.
We used the Geoprobe 6011DT to advance tooling at all non–limited‑access locations.
In total, 59 injection points were completed across the site. Treatment intervals varied, ranging from as shallow as 5 feet bgs to as deep as 30 feet bgs.
Many interior and some exterior locations required the use of our Geoprobe 420MÂ dolly rig.
To further minimize disruption to the tenant’s weekday operations, the team completed several interior injection locations over the weekend.
Upon completion, each point was bottom‑up tremie grouted using Portland cement grout in accordance with California Grout Standards: 3 gallons of water + 50 lbs of Portland cement + up to 3 lbs of bentonite gel.
We are proud of our crew for their professionalism, attention to detail, and commitment to safety throughout the project. Great job, team!
If you have any questions on this project, or if we can help support any of your current or upcoming projects, please contact us.
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