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You want to know how new remediation technologies work and which ones will get your projects across the finish line to meet your remediation goals. Pathways will help you get there.

This issue focuses on in situ remediation technologies including thermal treatment, plus the latest industry remediation news and events to keep you in the loop.

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SourceKill Gets it Done for DNAPL Train Spill Site

Early in the morning of September 28, 1982, nearly 40 train cars derailed near Livingston, LA. That fire burned for nearly two weeks as hazardous chemicals, seeped into the ground. The derailment forced more than 3,000 residents out of town for weeks and even months. Similar to the recent incident in East Palestine, OH, an array of cancerous chemicals including DNAPL and chlorinated solvents spilled into the surrounding environment.

After 30 years of pump and treat, PCE DNAPL still remained. Due to the high continued cost of pump and treat and no end in sight, responsible parties turned to an alternative source zone solution - SourceKill. SourceKill is an emulsified zero valent iron for chlorinated solvent source remediation. It is manufactured exclusively for Cascade by TEA, Inc., the first licensee of this NASA patent for DNAPL remediation at Cape Canaveral. SourceKill uses chemical reduction to primarily target known or suspected DNAPL source zones.

See Lessons from Louisiana: Livingston's long road to recovery -

Results: NFA issued in 2016 and $5 million in settlement money saved with SourceKill was used to invest back into the community.

For more information on SourceKill chemistry and how it could apply to your DNAPL sites, please contact Eliot Cooper at [email protected].

Technology Spotlight: Electrical Resistance Heating for Chlorinated Solvent Source Areas

Electrical Resistance Heating (ERH) works by passing current through the soil between an array of electrodes in a triangular grid pattern. This causes the soil and water to heat up to a maximum temperature of 100°C and results in boiling and vaporization of volatile organic contaminants from the soil and groundwater. The steam and vapors are then removed from the treatment zone by extraction wells. The vapors and any extracted liquids (water and NAPL) are then directed to an above-ground vapor and liquid treatment system for conditioning, phase separation, and removal of the contaminants before being discharged.

For ERH, the soil resistivity dictates how readily the soil will conduct electricity and how much heating will occur for a given current flow. The soil resistivity profile for your site determines: the length and how many stacked electrodes are required in each borehole, the optimal spacing between the electrodes, the sizing and design of the power supply system, and importantly how long and how much energy it will take to heat the site to design temperatures. The sweet spot range of soil resistivity for optimal ERH performance is generally between 10 and 500 Ohm-Meters (Ω.m).

TerraTherm, a Cascade Company, has completed over 50 ERH projects; all of which achieved the remediation goals while also meeting stringent health and safety and performance requirements.

Learn more about how ERH works and when it might be right for your sites.

A photo of an ERH site

Ask the Expert

How do you manage back pressure buildup in the borehole during injection to keep the project on schedule?

A pressure gauge is installed on the injection tool string manifold to indicate any back pressure that will have to be vented or subside before the rods can be added for top-down injection or removed during bottom-up injection.  However, this can add significant time to the project while waiting for pressure to subside, or the venting loses a lot of the amendment already injected.

A second option is to use a check valve above the injection tool that lets amendment flow through the valve but seals with back pressure once injection is stopped. This prevents any pressure buildup above the check valve so injection tools can be added or removed. The only downside to this approach is that once the borehole is complete, it is not possible to determine any back pressure build-up below the check valve, and when the rods are fully extracted to the surface, any back pressure will force injected amendments up the borehole.

Multiple injection tool strings are often required so that injection at new locations can commence while pressure at the injection location subsides.

Do you have a question for our team? Ask it here and our subject matter experts will answer it in the next issue of Pathways.

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Stop by to see us at the following events: 

DCHWS East Spring 2023 Symposium, Philadelphia, PA

March 29 – March 31, 2023

Remediation Expert Eliot Cooper will participate in a panel called “In-situ Remediation RD/RA Case Studies” where he will discuss “The transition to colloidal from micro-scale solids with further optimization through fully automated injection systems”.

Thermal Expert Steffen Griepke will be participating in a panel discussion called Thermal Remediation Case Studies and present a case study called “Challenges Encountered during the Implementation of the World’s Largest Jet Fuel Steam Remediation”.

International Symposium on Bioremediation and Sustainable Environmental Technologies, Austin, TX

May 8 – May 9, 2023

Cascade will be exhibiting and participating in a Panel Discussion on Geo-chemical in situ remediation. Come and meet us at booth #317.


Industry News

  • EPA Being Pushed Off the Fence on Coal Ash [link]
  • Expert new Standards for Landfills, Industrial Sites as EPA Tackles PFAS Discharge in Water [link]
  • EPA Proposes to Add Environmental Justice, Climate Change, and PFAS to National Enforcement and Compliance Initiatives for FY 2024-2027 [link]

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