Learn the Following in This Free Webinar:

  • In situ remediation with colloidal activated carbon eliminates risk of PFAS at a low cost
  • Colloidal carbon isotherm data and sorption test data for PFAS indicate excellent sorption capability and increased performance with decreasing carbon particle size
  • A single application of colloidal activated carbon at an actual field case site resulted in orders of magnitude reduction in PFAS groundwater concentrations to below USEPA health advisory levels

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  • If you need assistance with a current project and would like to get a design and cost, please visit our Request a Design page.
  • To get in contact with a REGENESIS Technical Solutions Manager use our Contact Us form.

Is that once PlumeStop is applied, it may need to be monitored for many years. The concern is that after a few years, there may be contaminant breakthrough which makes it hard for no further action reports to rely on PlumeStop indefinitely. Can you speak to whether contaminant breakthroughs are an unfounded fear and why?

Well, a really good question. It goes back to what I was showing you from Dr. Grant Keri’s work. We’ve done the sensitivity analyses on the length of time we expect to have the retardation. And it’s in the order of decades and decades. I do think, though, that if we’re gonna do a no-further-action that I think it should be contingent upon there being an annual groundwater sample taken from a sentinel well downgradient just to assure that the public, in fact, is protected and that there is, in fact, a break in the pathway to exposure.

So I think all the data shows that we should have decades and decades of retardation, but I think that there probably should be a requirement for a monitoring well downgradient but periodically sampled. And if indeed it does show up that there is contaminant breaking through, let’s say, in 20 years, you can simply just put in another, in this case, $73,000 of PlumeStop and you get another 20 years. We’ve done a lot of testing in the laboratory and shown that you can load PlumeStop on PlumeStop and there’s no impact on the amount of effectiveness of PlumeStop. Once you layer on another layer you have another 20 years or 50 years or 100 years. So, hope I answered that.

I actually have a 10 ppm plume of PFOA and need to get it down to 10 ppt. Will PlumeStop work for that?

Yikes, 10 ppm. Holy smokes. Okay. So, that’s a high concentration. I think that we’d be happy to look at that and see what type of impact we think we could have on it. We just would run it through the competitive sorption model and show you how much longevity we think we would have. I will say though that one of the places that’s a limitation for the effectiveness of PlumeStop would be if it’s in a fire training area where these high concentrations of PFAS might be co-mingled with diesel fuel that they were burning and they would go and… Diesel fuel they often put it out with a foam. If you have diesel fuel mixed with your PFOA, the diesel fuel, unfortunately, will competitively sorb on to the carbon and bump the PFOA off. So we’d have to look at that and we just ran it through the models and do some testing on it. But we’d love to do that, in fact, so please contact us.

How given the fact that the contaminant is not degraded and only bound up onto the PlumeStop in the subsurface, how has this been received by regulators?

Extremely well. I mean, regulators are aware that no further action is given in all the types of settings that I’ve mentioned. And if we can show that we bind it up and if there’s an adequate monitoring downgradient, there’s no reason that this shouldn’t be applied. If you look at pump and treat systems, when you put in a pump and treat system downgradient, remember, you’re drawing higher concentrations of these contaminants from upgradient downgradient. And as you’re doing that, you’re filling the flux zones with high concentrations, relatively high concentrations, of these contaminants which are forward diffusing into the lower permeable zones. Well, over time, though, that’s gonna have to come back out and back-diffuse.

So if you start pumping and treating as a solution, you’re actually gonna be retracting the entire problem if you’re pumping downgradient. And also if you’re collecting the PFOA or PFAS on activated carbon or IX brines, what are you gonna do with those? Are you gonna go take them off to another place and dispose of them? There’s risk anytime you transport this stuff or dispose of it someplace else. So, I think a lot of regulators are now saying, “Why not just lock it up and do a reasonable job of monitoring downgradient to make sure that, in fact, it’s captured and that there’s no exposure to the public?”

Video Transcription

Dane: Hello and welcome everyone. My name is Dane Menke. I am the digital marketing manager here at REGENESIS and Land Science. Before we get started, I have just a few administrative items to cover. Since we’re trying to limit our time to an hour, today’s presentation will be conducted with the audience audio settings on mute. This will minimize unwanted background noise from the large number of participants joining us today. If you have a question, we encourage you to ask it using the question feature located on the webinar panel. We’ll collect your questions and do our best to answer them at the end of the presentation. If we do not address your question, we’ll make an effort to follow up with you after the webinar. We are recording this webinar and a link to the recording will be emailed to you once it is available. In order to continue to sponsor events that are of value and worthy of your time, we will be sending out a brief survey following the webinar to get your feedback.

Today’s presentation will focus on eliminating risk from PFAS contamination via low cost, In-Situ remediation with colloidal activated carbon. With that, I’d like to introduce our presenter for today. We are pleased to have with us Scott Wilson, President, and CEO of REGENESIS. Scott has extensive experience in the development and application of advanced technologies for groundwater and soil restoration. He’s a widely published expert with over 30 years’ experience designing, installing, and operating a broad range of remediation technologies. He has expertise in project management and has directed the successful completion of large industrial remediation programs under state and federal regulatory frameworks. At REGENESIS, on specific projects, he plays an active role in technical oversight and program management to ensure conformance with customer expectations. All right, that concludes our introduction. So, now I will hand things over to Scott to get us started.

Scott: Well thanks very much, Dane. I really appreciate it. And thanks to everybody for joining us here. What I’d really like to go over and impart today in this one-hour time slot is an introduction to colloidal activated carbon and an introduction to environmental risk, and then a focus on the use of colloidal activated carbon to eliminate that environmental risk. This is actually a sort of an extended version of a talk that was given just last week at the National Groundwater Association workshop which was an actual meeting of sort of top regulators and consultants to focus on solutions to the PFAS problem that we’re seeing around the world. So, I hope to get through this and leave a little bit of time for questions. And with that, we’ll move right into it. I want to acknowledge Jeremy Birnstingl and Kristen Thoreson who were both instrumental in the development of colloidal activated carbon technology and who actually did a lot of the experimentation and development of what we’ll talk about today.

So, first off, what is colloidal activated carbon? Well, first of all, it’s not your grandfather’s activated carbon. It’s actually what we take is we take granular activated carbon, which you’re used to seeing in carbon canisters on pump and treat systems, and we actually mill it down to the one to two microns. And most colloidal or most granular activated carbon is 1,000 microns in size. There is some that’s only half that, it’s 500 microns. We take it and we mill it down to one to two micrometers. And that’s two to three orders of magnitude smaller than granular activated carbon. It’s actually milled down to the size of a red blood cell and we then suspend it in water. And first of all, carbon itself has a huge surface area, but when you take granular activated carbon and mill it to the size of a red blood cell, what you’ve done is you’ve been imparted a huge amount of wedded surface area to the outside. In other words, if you have a lot more surface exposed directly to the contaminant in the aqueous medium. As a result, you get extremely fast sorption.