25 Sep Fall Is Back to School Time
Fall Is Back-to-School Time
As our children “go back to school,” let’s revisit a core concept of activated carbon (AC) ourselves.
Activated carbon acts as an adsorbent, facilitating the adherence of substances to its surfaces. Within AC, these interactions occur in micropores where carbon plates are arranged in various orientations such that molecules interact with multiple carbon plates simultaneously at different angles and distances. Consequently, some molecules bind more tightly than others, resulting in an average binding strength for substances like MTBE, 1,4-dioxane, benzene, or PFAS.
Adsorption of organic compounds by AC is exothermic. In other words, energy is released in the process, and the amount of energy is compound specific. The fundamental principle to understand is that adsorption to AC is not permanent. Another molecule can come along and knock adsorbed compounds off through the liberation of energy. There is a dynamic equilibrium between the adsorbed concentration and the dissolved phase concentrations of chemicals. This underscores the need for a robust treatment mechanism, as activated carbon alone will not eliminate contamination: No matter how fine you mill AC, this fundamental does not change.
For over 22 years, RPI has been at the forefront of effective treatment of contamination. We integrate proven treatment mechanisms into all our BOS and CAT products, ensuring our products deliver long-term results. We “trap,” cutting off risk pathways, and “treat” to terminate the problem.
Kind Regards,
Ed Winner, PhD, Vice President
Remediation Products, Inc.
Transition Zone Characterization and Remediation &“The Passaic Gap” Series I |
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October 1st 12:00 PM EST – 1:00 PM EST |
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One of the most challenging regimes for in situ remediation is a transition zone; this is a zone that separates the overburden from competent bedrock and is typically partially weathered bedrock, weathered bedrock, or saprolite. There is no better example of this geologic setting than the Passaic Formation – a mapped bedrock unit that is predominantly located in New Jersey, Pennsylvania, and New York states. As an example, in New Jersey, much of the historical manufacturing and industrial sector was situated above this geologic unit and, typically, their historical impacts are realized as volatile organic compounds (VOCs) in overburden, transition zone, and bedrock. While most remediation efforts in the Passaic Formation have focused primarily on overburden impacts, and to a limited extent the competent bedrock, the transition zone is typically not well characterized or remediated. At AST, we call that transition zone the “Passaic Gap”. For many sites, this is the most problematic zone keeping a site from closure or monitored natural attenuation. Yet, as many of our clients know well, AST has unlocked the secret to treating this geologic zone with specific approaches and equipment. This presentation will describe how to characterize the Passaic Gap, and other analogous formations, using both conventional and modern techniques, and design successfully and succinctly for high-energy injections. Considerations and planning during the characterization phase will work towards the intent to inject specific reactants utilizing high-capacity pumps, with deference to the necessary overburden and/or competent bedrock remediation efforts. Multiple case studies from the “Passaic Gap” setting will be reviewed, including in the second part of this webinar series a focus on a performance-based contract site with serious transition zone and overburden impacts, including dense non-aqueous phase liquid (DNAPL). |
Reductive Dechlorination with Concurrent Sequestration of PFAS and 1,4-Dioxane in a Large Commingled Plume at a Former Manufacturing Facility & “The Passaic Gap” Series II |
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October 23rd 12:00 PM EST – 1:00 PM EST |
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Continuing AST’s focus on a combination of remedial techniques for weathered bedrock and competent bedrock, we are grateful to welcome Raymond Vaske, Senior Remediation Engineer, of Trihydro Corporation to present an in-depth look at the deployment of CAT 100 in the challenging Passaic Formation. This webinar encompasses the deployment of techniques discussed in Fall Webinar Series #1 with an advanced remediation technology for halogenated volatile organic compounds and emerging contaminants. The 3.85-acre confidential site, located in a heavy industrial/commercial area in New Jersey, includes an 82,500 square-foot manufacturing building where electroplating, and other operations were conducted for nearly 50 years. Site investigation activities conducted from 2020 to 2021 in overburden and bedrock groundwater detected high levels of chlorinated ethenes, including TCE, cis-1,2-dichloroethene, vinyl chloride, and 1,1-dichloroethene, as well as high levels of per- and polyfluorinated substances (PFAS) and 1,4-dioxane impacts to soil and groundwater. Regional geology in the vicinity of the site is characterized by an upper unit consisting of river alluvium and eolian deposits of Holocene Age, underlain by glacial unconsolidated deposits (clay, silt, sand, and gravel) of Pleistocene Age, and finally bedrock of the Passaic Formation, consisting of thin bedded shales, mudstones, and sandstones. This was a challenging geologic setting and a complex commingled plume. Yet, preliminary groundwater monitoring results indicate that reducing conditions have been engendered, as designed and intended, in all the injection areas with over 99 percent reduction in TCE in the target wells. This presentation will include a full evaluation of chlorinated ethenes, PFAS, and 1,4-dioxane, noting trends and exceptions. Complete details regarding site challenges, plus design and technology synergies, will be provided. |
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