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Given that PlumeStop was developed to disperse in the aquifer, what’s to stop it from remobilizing over time and increasing concentrations seen in production wells? Has this been tested to see if there are any soil types that it does not adhere to?

That’s a good question. So as we saw in that flow column that we looked at early on and we saw that painting of the aquifer…so that has to do with all those additives that are present within the formulation and as the PlumeStop adheres, that is a permanent picture and over time, the other additives will wash away or degrade which means that the mechanism for any movement of PlumeStop is now going to be removed over time. And so there really is no possible way for those particles to remobilize at that time without any kind of…basically their car has been taken away from them at that point. Then they will agglomerate and not to be able to move any further.

So we don’t see that kind of mobilization. And it is important to know that the amount and the extent of what we have PlumeStop deposit is going to depend on the soil type. And so we know that the more clay and silt that’s present, the more PlumeStop will adhere to it as opposed to a clean sand. So that’s something that we’ve taken into account and it’s important for us to know as far as understanding how far we expect it to go. So there is not any soil type that it will not adhere to. It’s just a matter of how much adhere.

Is it possible to reach the low levels required by regulatory cleanup levels?

Yeah, so that’s an important question, obviously. We need to make sure that’s possible. I think we have evidence because granular activated carbon is already used ex situ and the good news about activated carbon is that it actually works a little bit better at lower concentrations. The way that isotherms work is that they actually improve at lower concentrations. That’s where they get better which is in opposition to most technologies. Usually, it will lose efficiency at lower concentration. So this is a good part about activated carbon but in the end, yes. We can reach those regulatory cleanup levels with PlumeStop as well.

Can there be reinjection after the PlumeStop is spent?

Yeah, so that’s an important one when we’re thinking about PFAS since we don’t have a destructor pathway right now and so we’re talking only about sorption which means that there was likely a time point where the capacity will be filled up and at that point, there is no issue at all with going back and reinjecting more PlumeStop either into the same wells or same general area through direct push where it had been applied previously. We will see an additional coating go in that same area. We might see a little bit more transport slightly down-gradient but in general end up applying an additional layer of PlumeStop in that same area. And we also have some means of…that we’re working on right now to really control where the PlumeStop is going so we can try and make sure we get a nice, thick dose where we need it if there happens to be a soil type where we don’t see it as much deposition as we’d like. We do have a means for increasing that as necessary.

What analyses should be run to determine if PlumeStop is going to work including soil and or groundwater chemistry?

Okay, that’s always a good question, one we’re thinking about in situ technologies and I think there’s two parts…actually, question and one is first just getting PlumeStop into the ground. Is there anything that we look for? And we will tend to analyze for total dissolve solids and oncentrations because that can affect how far we expect it to go. However, the good news is that most concentrations you encounter in aquifers are really not going to have any impact there but it’s something we will check prior to injection to make sure we’re not going to run into anything that might limit its transport. But generally, PlumeStop can be used in wide range in redux, DOORP types. It’s really robust in that nature. The second part, I think, I alluded to a little bit is really understanding everything that’s present in that aquifer which means knowing all the contaminants or anything that might have TOC, anything that might have a potential to absorb the carbon because we can preferentially only absorb the contaminants we’re interested in. So we need to really know the full picture at every site so that we know how to design for it and make sure we get enough PlumeStop and to capture the contaminants we are interested in. so even if there are contaminants that maybe aren’t the one we’re looking for, we need to know about those as well to get the proper dose installed.

What about the shorter chain linked PFASs? Granular activated carbon is known to be largely ineffective for shorter chain lengths.

Yeah, so that is…when you have to think about granular activated carbon, it is going to have a stronger affinity for those longer chain link PFAS compounds like PFOA and PFAS but there certainly are shorter chain link present as well and the affinity does drop off and so what has been observed with granular activated carbon is and I would point back to one of the earlier slides that I talked about is that when we’re putting in PlumeStop in the ground and we’re using the natural flow rates, that total flux it’s going through is going to be whatever that natural flow rate is and so if we know all these isotherms, we know how they’re going to interact, it’s something we can design for. It may require multiple barriers in that case to get everything including those shorter chains which have less affinity but the trends are the same as far as what has been observed with other activated carbons.

Video Transcript

Dane: Hello and welcome everyone. My name is Dane Menke. I am the digital marketing manager here at Regenesis and Land Science. Before we start with the webinar today, I have just a couple of administrative items to cover.

Since we’re trying to limit our time to under an hour, today’s presentation will be conducted with 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 will 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 webinar will focus on PlumeStop liquid activated carbon with a technology overview on in situ Containment of Perfluorinated Chemicals. To give us insight into this topic, we are pleased to have with us today Regenesis manager of research and development Doctor Kristen Thoreson. Doctor Thoreson is the lean inventor of PlumeStop liquid activated carbon. She heads the chemical research and product development program at Regenesis. Her team is focused on developing advanced technologies for the treatment of recalcitrant compounds in mixed environmental media.

All right, that concludes our introduction so now I will hand things over to Kristen to get us started.