The Legacy team recently completed a direct push slurry application of EHC Reagent. EHC is non-toxic and works through in situ chemical reduction (ISCR) to break down contaminants into harmless molecules.
The project site was located in a mixed Industrial / Residential area of West Alameda County. The groundwater is contaminated primarily with Tetrachloroethylene (PCE) and Trichloroethylene (TCE) from a former dry cleaning supply business that occupied the property during the late 70's and early 80's.
EHC Reagent was provided by Evonik, and was delivered in 50 pound bags.
EHC is composed of controlled-release carbon, zero valent iron (ZVI) particles and nutrients used to promote treatment of contaminated groundwater.
To keep the solids suspended, EHC must be mixed in a thick 25%-30% slurry, thus special mixing equipment, pumps and injection tools are required.
We used one of our full size self contained Injection Trailers as our mixing and pumping platform.
Our injection Trailer was fitted with double action high pressure piston pump, fed by dual slurry mix tanks.
We also utilized a dual point high pressure injection manifold with high pressure hoses, instead of our standard multi point injection manifold.
We used digital Ultrasonic Flowmeters / Totalizers that allow us to accurately monitor injection rate and total gallons injection.
Our direct push tooling was advanced using two (2) Track Mounted Geoprobe direct push rigs. We had one Geoprobe 6011 and one Geoprobe 7822 on this project.
Since EHC is a thick slurry, it can clog small 1.5" diameter tooling, so we used larger 2.25" diameter injection tools. For this project we used our 2.25" OD Slurry Window style Injection Tools, fitted with check valves.
Slurry injections are a little different, rod string backpressure and daylighting is generally something that needs to be looked out for, and managed when it happens.
The available work area was small, so we set-up in a corner of the parking lot.
Due to limited onsite space, we also managed the EHC inventory at our local Benicia office, and made deliveries of the reagent as needed.
Jake Rounds and Abdiel Ramirez led the field effort, backed by experienced crew members from both the Northern and Southern California regions. Northern California Managers Brandon Moses and Jake Wilson also took a hands-on approach, actively engaging in the fieldwork. In the world of small business, everyone wears many hats.
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If you have any questions on this project, or if we can help support any of your current or upcoming projects, please contact us.