The Legacy Remediation team recently wrapped up a 4-week Direct Push Injection project in Los Angeles County, California for Fishbeck. The contaminants of concern we are remediating are primarily tetrachloroethene (PCE) and trichloroethene (TCE).
Fishbeck contracted with Legacy Remediation for the field work to implement an in-situ enhanced anaerobic bioremediation injection event using Electron Donor Solution – Extended Release (EDS-ER) provided by Tersus Environmental and KB-1 Bioaugmentation Culture provided by SiREM. EDS-ER is a Self-Emulsifying Vegetable Oil based Electron Donor. When mixed with water in the field, EDS-ER spontaneously becomes an emulsified vegetable oil (EVO) solution. Compared to factory emulsified EVO products, which is typically around 50% oil by weight, EDS-ER is shipped at 85%-95% vegetable oil by weight.
The Legacy team mobilized one of our standard self-contained Injection Trailers.
Space was tight onsite, so we parked our trailer and support truck in tandem along a loading dock .
The mixed EDS-ER Solution, KB-1 bioaugmentation culture and KB-1 flush water was all injected through our custom 10-point Injection Manifold.
We were injecting into 4-6 points simultaneously, with a combined injection rate between 30-40 gpm.
We prepared the EDS-ER by first adding Vitamin B₁₂ powder.
Since the dry Vitamin B₁₂ powder isn't soluble in the EDS-ER vegetable oil blend, we first mixed it with water prior to mixing it with the EDS-ER.
Tersus delivered the EDS-ER in 2,100 lb IBC Totes. The pink tint in this tote is from the addition of the Vitamin B₁₂.
Available storage space onsite was tight, and since Tersus had a nearby SoCal warehouse, we were able to schedule 3 deliveries.
We used KB-1 Primer, provided by SiREM, to prepare anaerobic water in tanks onsite. We injected anaerobic water before and after the KB-1 dose.
The KB-1 bioaugmentation culture was injected directly into our injection manifold.
The remediation compounds were delivered to the aquifer by both dedicated Injection Wells and Direct Push Injection Points.
Since the facility is very active, we utilized hose ramps, cones and delineators to protect and identify our work areas.
The direct push injection approach for this project was: top-down injection, targeting the site's shallow water-bearing zone (i.e., from approximately 30-50 feet bgs).
The injection points were located across the site and the available access varied. We utilized three (3) different sizes of Geoprobes for this project.
We used our Geoprobe 420M for the tightest and most limited access locations.
Our Geoprobe 54LT worked well in some of the points that were not quite as tight, like this location near some automated machinery.
Since we were injecting into multiple points simultaneously, the 54LT worked well as it can be easily moved back and forth between multiple points, in between advancing the Injection Tooling to the next treatment zone as needed.
We were able to use our full size Geoprobe 7822DT for the exterior points and for some of the interior points that had sufficient access.
For the two limited access rigs, advancing the tooling to the deeper injection intervals was not an easy task. We fabricated 6 foot bridges that we anchored at each active location. This allowed us to use the full down force of the direct push rig when advancing. With this design it allowed for quick set-up as we moved back and forth.
Since 90% of the injection points were located inside, we used ducting to vent the engine exhaust outside.
We cored the interior points with a 4" hole saw, then we used 3" hand auger to clear the first 5 feet.
At 6 of the injection points, we encountered a subfloor at 4 feet below grade.
For these locations we used 4 feet of core drill extensions along with a 3" core barrel to core through the subfloor. Once through, we continued to hand auger to 5 feet with a 2.5" hand auger.
I couldn't be happier with our team's attention to safety on this project. It seemed that around every turn we had something coming at us, whether it was automated machinery moving at will, swinging overhead linen bags on the monorail track system, or rolling carts being pushed by the onsite employees.
Even with all the limited access locations and the numerous site challenges, we were still able to inject an average ~12,000 gallons of remediation solution per day, and in the end we were able to wrap things up 1 day ahead of schedule.
If you have any questions about this project, or if we can help support any of your current or upcoming projects, please contact us.
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