- Eliot Cooper and Joe Wong

When a new remediation amendment debuts, it can sometimes feel difficult to cut through the marketing and get answers to your most important questions:

  • How does this amendment work?
  • What contaminants can it effectively treat?
  • Is this a cost-effective option for my current project or sites I’m likely to work on in the future?

That’s why today we’re sharing real-life questions we’ve received about our new colloidal activated carbon product (CCP), FluxSorb™ IS, as well as the answers provided by Cascade’s Vice President of Technology Eliot Cooper and Advanced Emission Solutions’ Chief Technology Officer Joe Wong.

 

Can CCPs be used near ecological receptors such as streams?

Yes, CCPs can be used near ecological receptors. If groundwater velocities are high enough to carry the colloidal particles toward the receptor, we have methods to accelerate their immobilization.

 

Can you remove a CCP once it is adsorbed?

Once the CCP is injected into the subsurface and is immobilized, it would be hard to remove. We recommend that the CCP is retained in the subsurface, since one of the advantages of CCP is its persistence and residence time required to treat contaminant mass.

 

Can you speak to activated carbon solutions that also stimulate biodegradation and the efficacy thereof?

Activated carbons are excellent hosts for biological organisms. There are a host of examples in water treatment, where biofilms are specifically grown on activated carbon surfaces for targeted contaminant biodegradation followed by adsorption into the carbon porosity. We design our carbon pore and surface features to be biological hosts for the organism, nutrients, and contaminants.

 

Do you use dispersants to accelerate permeation? Is so, do they work?

Yes, we use low levels of non-toxic additives to promote activated carbon permeation/mobility. It is required for good dispersion.

 

How does application of CCPs compare with ZVI? Are thickening agents recommended?

Thickening agents are not utilized in application of CCPs or our other colloidal amendment, CleanER iZVI. Our colloid injections are intended to occur at low pressure, targeting transmissive zones and to  avoiding fracturing. For larger micro-scale ZVI particle sizes that are used in fracturing for finer grained soils and weathered bedrock, thickening agents like guar are often used.

 

How does using CCP compare to ZVI or ISCO in terms of cost and performance?

The cost of using CCPs can be similar to other technologies, including ISCR, ISCO, and bioremediation. However, CCPs can reach groundwater target concentrations more quickly and with fewer injection events. This can result in significant life cycle cost savings depending on the specific site and goals. Additionally, CCPs are more suitable to meet lower groundwater concentrations, e.g., MCLs for our primary target, including chlorinated solvents and petroleum hydrocarbon.

 

How effective is this technology in clay soils?

We don't recommend injection of any liquid amendments—including CCPs—in clay soils. We typically would recommend larger particle size powdered carbon that can get better distribution in clay through fracturing.

 

How can one predict the useful life of a CCP treatment?

A first order magnitude of CCP life can be estimated by evaluating the adsorption isotherms of the contaminant(s) with various CCPs and applying Freundlich Adsorption Isotherm modeling. Calculating breakthrough time in years, by modeling groundwater velocity, contaminant flux, and degradation rates can be done in parallel. Properly designed barriers can have a projected lifetime of 30 years or more.

 

I heard there can be issues with fast breakthrough using activated carbon. Do you recommend the use of colloidal activated carbon and IX resin in tandem use?

We don’t recommend using IX resin in tandem use. Using the adsorption parameters for a specific CCP, detailed calculations can allow us to design applications to last 30 years or more without breakthrough. Cost effectiveness and barrier lifetime will depend on the contaminant concentrations, groundwater velocity, degradation rates, and other factors.

 

I’m interested in possibly using CCP as an in situ "polishing" step for groundwater a short distance upstream of gw/sw interface. Is this a good idea?

This in situ polishing step is an appropriate application of CCP. It would benefit from the use of controlled immobilization technology to keep the CCP out of the stream/lake.

 

Since the adsorption of pollutants on carbon is a reversible process, will there be the need to do additional treatment in the area?

If it isn’t, will the retained chemicals leach again? Does carbon affect the efficacy of ISCO procedures that might be done later in the same area?

The "reversibility"/desorption of contaminants requires a large driving force if the pore structure and surface chemistries are designed for enhanced sequestration. Therefore, we don’t expect the need for additional treatment. Should additional ISCO be planned, one would have to ensure the amount of carbon in the subsurface is included in the demand ISCO demand. This would be similar to including soil oxidant demand (SOD) in overall oxidant dosing for traditional ISCO projects.

 

Have you performed any testing on PFAS-contaminated soils using CCPs?

We have conducted a variety of lab adsorption isotherm studies with various PFAS mixtures and with various powdered activated carbons in the 10-20 um D50 size. We are beginning to gather lab adsorption isotherm data on CCP size products.

 

Have other questions or want to learn more about colloidal activated carbon? You can watch our on-demand webinar, Colloidal Activated Carbon for Hard-to-Treat Contaminants, or contact Eliot Cooper to set up a time to chat.

SCHEDULE A CALL >>

 

ABOUT THE AUTHORS

Joe Wong

Chief Technology Officer at Advanced Emissions Solutions
[email protected]

Joe has over 35 years of industrial leadership experience in research & development, product development and business growth in specialty materials. He has deep knowledge in activated carbon development and application and brings a fundamental scientific yet commercially viable approach to building products and businesses. Prior to joining Advanced Emissions Solutions as Chief Technology Officer in 2019, Joe was the Chief Technology Officer for ADA Carbon Solutions starting in 2011. He led a high-performance technology team in activated carbon product development and technical services activities to drive rapid company growth in environmental solutions for the coal power sector. Before ADA Carbon Solutions, Joe worked three years in private consulting, spanning a variety of Lean Six Sigma continuous improvement and operational contributions. Prior to consulting, Joe spent 21 years with MeadWestvaco Corporation in senior leadership positions for the Specialty Chemicals (now Ingevity) and Research & Development sectors. At MeadWestvaco, he led technology and market teams in the development of specialty activated carbon products for a variety of industrial, consumer and emerging markets with concentration in automotive gasoline emissions control. Joe holds a PhD. in Chemical Engineering from the University of Texas.

 

Eliot Cooper

Vice President, Technology
[email protected]

Eliot Cooper is the Vice President of Technology and Business Development. In this role, he helps clients design efficient and cost-effective remedies using high resolution site characterization (HRSC) and a vast array of remediation options. His specialty is finding the right combination of tools and technologies for complex sites, and ensuring every step of the remediation process is optimized to achieve results.

Eliot draws on a career that spans more than 30 years in the environmental remediation industry and includes hundreds of projects nationwide. He’s remediated sites that involved hex chrome, fuel spills, and chlorinated solvents. He specializes in injected remedy delivery, remediation design support, characterization of VOCs, and tackling complex sites by combining multiple remediation technologies.

Eliot previously served at the Environmental Protection Agency in both air pollution and hazardous waste management programs, as well as in the private sector providing thermal combustion and in situ remediation field services. Eliot now leads Cascade's in situ remediation solutions team to evaluate available technologies to meet client goals, provide advanced delivery techniques, and ensure HRSC results in actionable solutions.


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