Provect-IR ISCR Injection with 3230DT

The Legacy Remediation Northern California Team recently completed a successful Direct Push slurry injection at a project site in Sonoma County, California. The groundwater remediation strategy involved the injection of Provect-IR, supplied by Provectus, followed by bioaugmentation with the KB-1® microbial culture, provided by SiREM.

The project site is located at a shopping center that formerly housed a dry cleaning facility. The primary contaminant of concern is tetrachloroethene (PCE), which was used at the facility until operations ceased in 2003. The objective of our injection effort is to reduce PCE concentrations in the groundwater in and around the source areas.

We utilized one of our full-size, self-contained injection trailers as the primary mixing and pumping platform for the project.

While our support truck typically carries field supplies, on this project it also provided hydraulic power for operating the slurry mixers and injection pump.

This image shows the interior of our injection trailer, featuring a double-action, high-pressure piston pump supplied by dual slurry mix tanks. The system is capable of mixing and injecting up to 20 gallons per minute (gpm) at pressures up to 1,000 psi.

We also utilize digital ultrasonic flowmeters and totalizers, which enable accurate monitoring of both injection flowrate and total volume injected.

Due to the lack of available and secure onsite storage, all reagents were shipped to our local office in Benicia, CA.

From there, we made daily deliveries to the site as needed to maintain continuous progress.

Our mix water source came from a nearby fire hydrant.

Legacy coordinated with the local water agency to have the construction meter installed.

The Provect-IR was provided in 50 pound bags.

It was mixed in alternating batches in our mix tanks.

The Provect-IR dry product was mixed into a 30% by weight slurry to maintain solid suspension, resulting in a thick, stable mixture, as shown in the image.

Despite the slurry’s high viscosity, we successfully maintained injection pressures at the manifold between 150 and 200 psi.

As usual, each direct push injection point was hand cleared to 5 feet prior to advancing the Injection Tools.

Plastic was laid down to keep the asphalt parking lot clean.

The injection tooling was advanced using a Geoprobe 3230DT. If you are not familiar, the Geoprobe 3230DT is a very versatile drilling rig capable of both auger and rotary drilling.

What sets it apart, and what we value most, is that it’s also the most powerful Direct Push rig available. Weighing nearly 18,000 pounds, it features a robust GH-70 hammer. While this power can be demanding on tooling, it also enables penetration to depths where other rigs often encounter refusal.

For this project, we utilized our larger 2.25-inch diameter, window-style injection tools equipped with check valves.

The injection approach was bottom-up, targeting 2.5-foot treatment intervals between 35 and 75 feet below ground surface (bgs).

We selected the Geoprobe 3230DT for this project specifically to accommodate the required injection depth of 75 feet.

We used our standard 2.25-inch injection cap to connect to the probe rod and we used the 3230DT’s hydraulic head clamp, which provides up to 80,000 pounds of pullback force, to manage the pull-backs.

Given the potential for high pressures during slurry injection, we utilized our 1-inch high-pressure injection hoses, rated for up to 3,000 psi, to ensure safe and reliable operation.

Since the injection points were located throughout an active shopping center, we deployed multiple sets of hose crossover ramps to minimize our impact and ensure the safe flow of vehicle and pedestrian traffic over the hose lines.

The KB-1® microbial culture was provided by SiREM and delivered in standard stainless steel vessels, which were evacuated using nitrogen inert gas.

KB-1® is a naturally occurring, non-pathogenic microbial culture containing Dehalococcoides (Dhc), the only known group of microorganisms capable of complete dechlorination of chlorinated ethenes to non-toxic ethene.

All of our injection trailers are equipped with custom large- and small-dose bioaugmentation measurement tubes.

For this project, we injected 150 mL of KB-1® microbial culture into each of the sixteen (16) 2.5-foot treatment intervals. Our small-dose measurement tube made this process efficient and precise.

Anaerobic water was prepared onsite, and was injected during the bioaugmentation process.

This was injection sequence for each of the sixteen (16) 2.5-foot treatment intervals:

• 21 gallons of Provect-IR Slurry

• 5 gallons Anaerobic Water

• 150 mL KB-1 Microbial Culture

• 5 gallons Anaerobic Water

• 21 gallons Provect-IR Slurry

Two thumbs up from the client favorite Brandon Moses, our NorCal Operations Manger, regarding the Geoprobe 3230DT!

If you have any questions about this project or would like to discuss how we can support your current or upcoming projects, please don't hesitate to please contact us.

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