Today’s webinar will focus on a UST site where molecular biological tools, magnesium sulfate, and PetroFix  achieved site closure.

With that, I’d like to introduce our presenters for today.

We are pleased to have with us today Rob Thompson, senior manager at Antea Group. Rob Thompson has more than 30 years of industry experience. With a focus on site characterization, conceptual site model development, remedial design and implementation, and project management, he has provided senior technical support for assessment and remediation solutions to private, commercial, industrial, and municipal clients throughout the US, focusing on injection, remedial evaluations, and remedial implementation for sites contaminated with petroleum hydrocarbons and chlorinated solvents. Rob Thompson is an SME within the firm’s probabilistic modeling services.

We’re also pleased to have with us today Todd Herrington, Director of Product Management for Regenesis. Todd Herrington has 25 years experience in the remediation industry and an in-depth understanding of the complexities of in-situ remediation, having evaluated or implemented mechanical, biological and non-biological in-situ remedial technologies at over a thousand sites. At Regenesis, he collaborates with industry experts to generate innovative approaches to site remediation problems with a particular interest in colloidal technologies.

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

All right. Great. Thanks, Dane. So today, yes, molecular biological tools, magnesium sulfate, and PetroFix achieve site closure. That’s going to be the topic of discussion. We’ll highlight some of the lessons learned and the things we did. It finally achieves closer at the USG site in Wilmington, North Carolina. So moving on, I’ve just included this slide just because there’s this nice quote I like to have here, a quote my grandfather said and that I heard a colleague say it several years back.

So I’ve included in more or less my motto of how to go through things, especially in the work world here. So just a little bit info. So here’s our site, just a little area. We had a drone fly over this to get an updated aerial for us. We have our target area right here, and a couple of cross-section lines that we had. The key wells here are MW 16, 15, MW 2, and MW 18 are essentially where the remaining mass was that we had to target for the remediation.

And you can see there’s few of these things here to consider receptors or something definitely we had to consider here. You can see there’s an old water supply well there and they were also in the in the area.

The hydrogeology geochem, the types of contaminants, and of course the microorganisms present were all factored into figuring out what type of media approaches we need to do. So a little bit about the site and the setting. It’s a UST site where we had two 4 ,000 gallon gasoline USTs and one 4 ,000 gallon diesel, where they were used for fueling their fleet vehicles from prior operations.

And the source areas were primarily the former UST basin and the surrounding soils. And the site was designated high risk due to supply wells in the area. So that’s definitely something that drove this for so long. Geology here, we’re in the coastal plain, which is primarily sedimentary environments and silt and clay.

We have some clay lenses up in the shallower zone and it grades down into more of a finer to medium sand as we go deeper. Generally anaerobic conditions site-wide, groundwater shallow three to six feet, our pH range here five to seven, so a little bit on the lower side there on towards the five for microbial preference, and our targets were benzene and naphthalene because of the 2L standards here for groundwater of 1 and 6 micrograms per liter.

Corrective action that’s been done in the past was excavation when the tanks were initially removed. Oxygen release compound was placed back then in like 1999, and then the rap was written and the remedy was monitor natural attenuation from 2000 to 2011.

After that, the regulator said, hey, can we do something different out here and look to do some other alternative technology? So we opted for the magnesium sulfate injection. We did a couple of those injections in 2012 and 13, another few in 2015 where we added some buffer.

We did consider Plumestop and ORC Advanced back in 2017, that was before PetroFix was available. And we moved on to the ORC advanced filter socks, which were placed directly in some of the monitoring wells. And then ultimately PetroFix was the final remedy for the site. So looking at the magnesium sulfate injection, our initial injections in 2012 and 2013 are shown here on the left, where when the state reached out to us, they said, hey, you could do a new technology cleanup plan, which was reimbursable.

That was a big driver here with this site, too, was the trust fund and the reimbursement of the work. So we said, okay, we can use the magnesium sulfate solution. It was approved in the state. Our injections here included three initial events and at a spacing of about 18 locations, targeting the five to 15 depths, pretty much where we had about 17 and a half gallons a point, only 315 gallons for the whole event.

Over the three, we had 945 gallons total and we did see a notable increase in the sulfate reducing bacteria. Now the magnesium sulfate, the concentration, let’s see off the top of my head, is very high. It’s on the order of 120, 130 ,000 ppm.

So there was a lot of magnesium sulfate in this solution. So we had to do it another few injections here in 2015 and 2016 after we saw some results, but we weren’t getting quite where we needed to. So we did three more events. We just increased the quantity of the solution. It was the same concentration, same target area with the 18 points and then just essentially doubled from 17 and a half gallons to 35 for each.

And you can see the totals for the whole three events that we did there. During this time, we added a magnesium hydroxide buffer to help with the pH. And we did maintain a sulfate reducing bacteria population. So that was good to see that.

Just a little couple of looks here at the application area from the first slide. Here’s our target area with our 18 points and just zoomed in here. You can see we’re trying to capture MW 16 and 15 and two. MW 18 was a little bit out of range because there was a ditch here at a fence line and this was heavily wooded.

So we have to clear the whole area there. So we couldn’t really get into that area at the time. So we targeted this and you can see where the tumor tank field was.

And just keep in mind this kind of this layout because I’ll get into this later on is where MW 15 is and where the edge of this excavation here from the pavement change was. So the excavation didn’t extend out into this area. So I can touch on that here in a few more slides. So looking at some of our initial results pre magnesium sulfate injection, you can see here, I’m gonna call MW15 here as kind of our source area, our target zone.

It’s really high concentrations there. And then here about not quite a year later, you can see things have really dropped off and the bulk of the mass was kind of outside of the treatment zone. So that was very exciting to see that from our first rounds of injections.

So then looking at the next round, we went back and we doubled our dose and you could see here that we don’t have many of these bright orange and red colors, which was good to see. And then even over time here by 2017, we still have some of these aliphatics kind of hanging around, just showing that the mass is still present. So prior to the injections, we did some microbial work.

And, you know, back in 2014, we said, all right, well, here, let’s do background, which is kind of, it’s MW3, this is MW3 here. You don’t see too much activity, although you do see some of the sulfate-reducing bacterias here in the kind of the mid-range.

MW2 is further down gradient from MW15. And then, of course, we have MW-15 over here. So a little bit of sulfate reducers here, but it was kind of surprising not to see many of those sulfate reducers here. But you can see above here, the sulfate was only 70 milligrams per liter at MW-15. So what went in was probably consumed pretty quickly and not much of it remained.

And here below, this was from the second injection where we increased the dose And we kind of targeted, we shifted some of the locations to where we targeted the areas where we really needed to have the most effect. So you can see a big jump in the sulfate reducers. We didn’t test monitoring well three during this time, it was just two and 15 were really where we focused.

So this was good to see, even some of the anaerobic BTECs degraders here, but a good increase in the sulfate reducers and also these anaerobic alkanes, which they utilize the alkanes from the C6 to 18 range. So that kind of falls within the mix of the gasoline and the diesel that we have as the type of contamination here.

And then some of the other slides here, I’ll be able to show there’s some decreases in some of those aliphatics too. But the sulfate reducers were what was targeted. So that was good. That was really good that we got to that level. but it didn’t really fade away. It just kind of paused or stagnated, kind of. So in 2017, I reached out to Regenesis. I said, hey, is there anything that we can do here?

We did pneumatic sulfate. We saw some good reductions, but I still have some of this mass hanging around. This is just showing BTEX here. Here MW15, the just total BTEX was 7 ,700 micrograms per liter. So still present, not so much here in MW-16 and not so much was really showing here in MW-2. So in 2017 PetroFix wasn’t available yet. So part of the design here was a two-step process.

The first was treat this entire area outlined in the green by laying out a grid of let’s see 40 application points and treat that with ORC advanced to add electronic scepter, increase oxygen, kind of switch it to aerobic conditions to stimulate the bacteria to degrade that dissolved mass, and also affect whatever the source area, this higher area in the blue to, you know, stimulate some of that degradation as well.

And then follow with the plume stop to treat any remaining mass in the core of this plume, which eventually treat that core and also support any bioremediation outside of it as groundwater flows through the plume.

And then speaking of groundwater flow, I didn’t touch on that, but it generally flows kind of from, I guess that this is so northeast to southwest, but it fluctuates.

It, you know, you can see there’s a little ditch and there’s a stream off the side here that’s not in that image. But when we looked at this, the overall costs were just too high.

The drillers, for their efforts to do the 40 application points of the ORC advanced and then come back again and hit the core with the plume stop, it was just cost prohibitive.

So we kind of had to just shelf this and think about some other options. So some of the other options that came up were, all right, I’m talking with the regulator, they said, well, the fund isn’t wanting to fund any more injections out here, so what else can we do?

And they actually suggested these ORC advanced SOCs placed directly into the monitoring wells. And I said, okay, well, you know, if that’s reimbursable too, you know, it’s easy application. So I said, okay, let’s try it. And, you know, it’s a, it’s a calcium peroxide, it releases oxygen for the enhanced aerobic bioremediation.

You know, we put eight to be strong, eight to 10 of these together, depending, maybe, maybe six in one of the locations, but we just strung them together, lower them down in the wells to see what we could get as far as stimulating aerobic conditions and the aerobic biodegradation.

Again, the site’s been pretty much predominantly anaerobic. So I was a little skeptical, but you know, the regulators suggested it and said, okay, we’ll give it a try. We found some localized aerobic conditions in these wells. You know, the DO went way up, the pH increased.

So we figured, okay, maybe we’ll see some, you know, some benefits here. And then when we looked at some of that, we said, All right, well here, here is benzene and naphthalene in 2018 during the ORC advanced use. So again, MW15, here’s our hotspot in both locations from, oh, here’s naphthalene, here’s benzene in MW15, and then about a year later, that there’s not a lot of change in that shape.

So we didn’t really think that that was gonna be a long-term solution. Same thing here with the naphthalene, still pretty high levels in MW-15 and even as we saw some increases out here in MW-18. So all right, time to think things through again a little bit.

Looking at some of the microbial work that we did throughout this whole process, there’s still some sulfate reducers, these anaerobic alkane reducers, they just dropped off. But, of course, we have some of the aerobic betex reducers that they welcomed the oxygen from the ORC Advanced, and they stimulated their growth.

So that was good to see the growth stimulation, but we still didn’t see much of a degradation as far as the contamination. Up above you can see here low sulfate, 21, 49. So we hadn’t added any more sulfate. That’s just residual from the initial magnesium sulfate application. And those six total applications we did of that. But we did see the increase in the BTECs degraders and a decrease in almost everyone else.

Those anaerobic folks, they just said, no thanks, we don’t prefer these conditions, so we’re just gonna sit this out. So all right, great, now here we are after a year of this, now what do we do? Well, by this time, PetroFix had come on the market, I had been working with Regenesis using some of the plume stop at a few sites.

And we started looking into using PetroFix here at this site. So when I went to the client, think back to the plume stop slide where we were treating the dissolved portion of the plume and the core.

At the time, the budget was already set. The client had already had set the reserves for the year and I was a little bit late getting to it with my design and my costing for this PetroFix application. So I said to them, hey, if we can treat the core of the plume, which is essentially MW2, MW15 area as best we can, with PetroFix, I think I can fit it in with the budget that you guys have approved for the year. And would that be something you’d want to do?

So they were, they said, oh, if you have, we can, we can move with some remediation here and we can make progress. Yeah, let’s, let’s try that. So that was really great to hear. So off we went looking at the use of PetroFix  here. So during that process, we reached out to the agency and they said, yeah, that’s fine.

It’s approved.

But being in Wilmington, the Cape Fear River was impacted by PFAS. That’s a well-known thing from some of the upstream contributors. And with that, the agency said, you guys have to ensure us and prove to us that you’re gonna be using PFAS-free water for your mixing.

So, okay, all right, that’s we can do that now I’m scratching my head how do we know where am I going to find PFAS free water so I said the drillers should know some of this information because they they do the remedial work all around the state and all around the area so I had them I asked them to reach out you know some of the counties and stuff and they went looked as far as three counties away I figured maybe there’s a source somewhere maybe there’s a water supply that gets it from the groundwater somewhere that is PFAS free and the agency’s been sampling these water supplies and we can find some information that way.

So while they were doing their part, we looked into it as well.

And DEQ had been sampling the Cape Free River and groundwater and everything in the area. And as it turns out, Wilmington has two sources, the river and groundwater for their drinking water.

So I said, okay, well, let’s identify what part of the distribution system is coming from the groundwater and which is coming from the Cape Fear River, find a hydrant from the groundwater, because the data from the groundwater is something that DEQ was doing, showed that PFAS were, you know, they were non-detect or they were very, very low levels below any of the action levels.

So we identified that and we finally found our PFAS free source for the mixing. So that was great. PetroFix, it’s a really small, it’s one or two micrometers in diameter that could colloidal activated carbon.

So this is, it’s a very fluid, It’s, I look at the vials and I see things that I see that when I go to some of the conferences and it just looks like ink. You just took some ink and you put it in water. That’s essentially what it looks like. And it really is very fluid like that.

So we figured, great, let’s go for it. And it wound up to be the first application of PetroFix in the whole state. And we used about just over 16 ,000 gallons and we targeted that accessible area with the highest mass. And we saw some daylighting during the process, which I’ll explain here in a couple of slides why I think that that was actually a benefit.

Generally daylighting means, oh, something’s going wrong. But I think for this site, we had some unique situations where it was quite helpful. So this was the general layout for the PetroFix.

I kept the grid just for, you know, ABC123 kind of a grid location. So, we targeted MW16 and where the plume was, so that’s why we targeted kind of this whole area here with the application, MW2 is way down here, and there’s that fence line.

So we couldn’t really get much beyond here with the volume that we had and the access with the geoprobe to get it in the ground. So during the application, we did some design verification, right? So we had geoprobe out there, I said, all right, guys, let’s do some borings.

So we did a few borings up here by MW-16. We did a boring that was off over here. And then we did a few over here by MW-15, which was our hotspot. And we did some other borings down here towards MW-2. So looking at the pictures, you can see the shallow zone here.

We ran into this clay, which I kind of alluded to, is where when we got these borings out of the ground, these ones here were from right near MW-15, which was beyond that limit of the excavation when the tanks were removed.

So they stopped, they didn’t get all the contaminated soil, essentially is what happened here. So the clay and the silt up in the shallow zone, you could just smell it.

And I’d wish that we had done some high res or some other preliminary work prior to this, but here we were, so we were just, you know, marched on. But here after the injection, I said, let’s do some more borings, I want to see what we got. And you can see that clay there, and you can see even a little bit of impact, the PetroFix there.

But all this below it is just totally saturated with the PetroFix. So we knew that we were applying it at the right flow rates and the right pressures to get it in the ground where we needed it.

So looking at some of the results, we said, okay, well, before PetroFix , we sampled the wells. Still have this little plume. Now, this is 10, 50, 50 and below, I’d say, is probably what we’re looking at here as far as the concentrations, but the target was one for benzene.

Again, drinking water is in the area, high risk site. You gotta remediate to below the groundwater standard.

So a couple of years later, we sampled MW-16, just totally taken care of, and just a very little bit of area here around Hang It’s still around MW-15, which I think in part here is that residual soil that was probably likely treated and absorbed some of the mass in the area of MW-15.

So as groundwater fluctuates and comes in contact with that unsaturated soil that had now been pretty much coated with the PetroFix, there was less of it that was leaching into the groundwater and contributing.

And I think this is a good, this pretty much shows what the results were. MW2 is still out there, but remember our injection ended just up in this area, so we didn’t quite directly hit that with the application. So if we look at the naphthalene, here’s pre-PetroFix.

This is kind of that, you know, after the ORC socks, still a bunch of naphthalene up here, and then we have really good results right after, with only a little bit of naphthalene showing up in MW18. But again, some rebounding and groundwater fluctuations. We saw a little bit of rebound here.

MW-15 and MW-16 are totally taken care of. I mean, that plume was essentially cut off as far as the naphthalene to where we had, this was just essentially the untreated area because we couldn’t physically get to that with the drilling equipment.

So, and then over time, it wound down here, with the naphthalene, we’re getting close to being down, this is probably, I don’t know, maybe 20 micrograms a liter.

But again, our goal was to get down to six. So we did some more molecular work, but used the MVTs again. And you can see here, December 22, sulfate in MW2, our sulfate reducers are still hanging around. Our aerobic BTEX guys are around, but we see some more of the different degraders showing up here post-PetroFix.

So that was good to see too. Not so many down here, But over time, you know, this is January 24, a lot of that contamination had been treated and degraded by the PetroFix in the prior application.

So my suspicion here is that we saw some increases here, same thing here in MB15, and a little bit of decrease here as far as the microbial population, because they were running out of food essentially, so they were just, you know, sitting it out again.

So that was still good to see that we had some good biological activity post-PetroFix. So looking at some of the sample data, I thought this was interesting. I remember I reached out to Todd Herrington at Regenesis and I said, why am I seeing what I’m seeing in this post-PetroFix, particularly with the benzene levels here?

So you can see a significant decrease, right? This is the baseline pre-magnesium sulfate up here. You can see here’s the aliphatic CC9 to 18 aliphatic 45 ,000. I mean, that’s an order of magnitude drop as the initial application. And eventually when you get down here to the post-PetroFix, all these other compounds are pretty much taken care of.

Some of them increased. You can see in here, I like how I set up this table to show the dates, the type of remedial technology used, and then you could see the results.

So this wasn’t good to see, especially this one here. I was like, all right, we got to do something. This kind of really triggered looking into the PetroFix that had since become available at the time. So historically we’d use low flow sampling as the methodology.

And after the PetroFix, we use multiple methods. I tried the low flow, we use PDBs, we did filtered samples, but DEQ doesn’t accept filtered data. But we didn’t know where was the PDB placed, where was the tubing placed?

So when I was talking with Todd, those are some of the things that he asked. He said, do you know what depth your PDV was placed? And how does that compare to the depth where the tubing was at? I said, oh, geez, we didn’t, we don’t know that.

So that was a good, good thing to learn was pre and post application, depending on your sampling methodology, make sure you know where the intake is.

Because when we think back to the silts in the clays that we saw shallow, there were little stringers of silt down into the saturated zone.

So if that PDB was lowered into the well and it was adjacent to a zone like that that might have more residual mass, well it’s going to contribute more to the water and if the PDB is going to pick it up. Same thing with the tubing.

If you’re pulling your sample from an area where you have more residual mass coming into the well and you just essentially sample that little area, you can see your not really skewed results but you’re not really seeing the real picture.

So sampling by Baylor is totally approved and a doable thing here in North Carolina. So I said, you know what, let’s go back to using Baylor’s. We’re going to purge our three volumes. We’re to measure our parameters so we get stable parameters and everything before we sample and we’re going to collect our sampling.

So I think that when we started using the Baylor’s again it really helped to kind of, I guess, normalize some of the data in the concentrations as So we were getting actually maybe even a more representative sample in the well. But still you can see that all these other compounds still remained below standards.

So that was good to see. We had a little jump in the end in the benzene, but overall the agency had changed the way that they look at some of these sites that are high risk. So that didn’t play much of a factor in, plus we had such degreasing trends with overall contaminant mass.

Something else we did was, I put these well booms in. These pictures are not from this site. That’s from another site that we used them at in Mississippi. But it helps stimulate the microbial activity in those wells, especially post-ORC, post-PetroFix.

As you remember, we saw how much the microbial population just took out on the sideline for a while during the ORC application, but then they woke up during the PetroFix. So I figured let’s help them wake up and I put these well booms in the wells.

I saw a demonstration of this at a conference one time and I was pretty impressed. I mean, you put them in a well for when you have a little bit of NAPL, maybe a tenth of a foot, couple of tenths of a foot.

Generally I say, if it’s not worth baling, like if you go and you pull your first baler out and you’re not getting anything else as a waste of time, you can use these well booms for that NAPL. But we use it here at this Mississippi site.

and when I just I thought that over here somebody just poured DI water in the baler took a picture but nope this was what maybe three weeks here not even a not even a full month after the initial placement of that well boom there so I figured all right we don’t have NAPL here but maybe it’ll help stimulate the microbial population so the overall progress you know by well here we have our you know our wells from from this is 2011 and then we get into the mag sulfate work, some increases here, but overall, you know, we’re getting down to where we’re meeting our criteria for our groundwater standards with the benzene, and then you can see some overall decreasing trends here with the naphthalene.

Another thing we did, we said, well, here, let’s just look at the average benzene in those four wells, and you can really see pre-magnesium sulfate, magnesium sulfate, ORC, PetroFix, post-PetroFixed time, overall decrease.

I mean, the trend line is just straight down almost. But definitely, overall, just really, really good progress. Some good things we learned along the way were that, don’t be afraid to collect data.

We collected a lot of microbial data. We sampled multiple ways. The one thing I would say that I wish maybe we would’ve done is we would’ve done a little bit of maybe high-res work or done some probing out there before we did. The PetroFix, because I think that would have helped identify that soil mass and maybe have a, you know, tweak the design a little bit, maybe.

But overall, the PetroFix was able to handle it. You know, I’ve heard this trying to flip the chemistry from time to time, you know, depending on the site conditions. I don’t know, that maybe has a 25% success rate, you know, from what we’ve seen at our sites that we’ve tried to do that at.

You have to use a lot of material. Now, the plume stop and the ORC advanced, we probably would have been able to get the plume converted to aerobic conditions with that type of application because we were covering it all.

I probably would have been able to flip the chemistry, so to speak, if we would have done that, but doing it by well like we did now, that’s not a good way to go. The first application of PetroFix in North Carolina was successful, there’s no doubt about it. In that daylighting, we saw it was bubbling up the asphalt, so we’re adjusting our flow rates and our pressures to keep it from just spilling out all over the surface.

But I think that really helped, especially in the area around MW15 where we had some residual contaminant mass that was in the soil that we didn’t know about. But as soon as we found it, we knew what was causing the ongoing concentrations in MW15.

And you may need use multiple, you know, technologies. We used magnesium sulfate, the ORC socks, the PetroFix. We did add the electron acceptor.

We added the nitrate and the sulfate electron acceptor to the PetroFix application.

So that was, you know, that was good. And with that, I will turn it over to Todd Herrington and he can pick up his part of the webinar. Rob, thank you so much. Really appreciate it. That was a presentation and exciting to see the first closure for you know PetroFix in North Carolina.

I just happen to be a relatively recent North Carolina resident and Wilmington’s not that far away so that’s pretty exciting. So you know this is great to watch Rob’s presentation of this data.

I was somewhat familiar with it but certainly not all the details and thinking through how I wanted to wrap up today and provide value to our listeners. I picked three advantages of using colloidal activated carbon or PetroFix for hydrocarbon radiation.

It was somewhat inspired from some of the topics, Rob, that you’re going to be talking about last week. And so I’m going to get into those three, and I think they’ll be a nice area to delve into for a little bit more detail that some people might be wondering about.

All right, I want to highlight something that was alluded to in one of Rob’s photos, which was showing a black inky soil core. And one of the advantages of colloidal technology is the ability to distribute into an aquifer homogeneously.

So we just have been researching colloidal technologies for quite some time now. The first one we released was PlumeStop. And the original goal was twofold, I think. It was to improve the ability to get an amendment into the subsurface.

Regenesis being primarily in situ, mediation technology company, this is very important. The other thing was to help with back diffusion. And then so, coming across Plume Stop is a milled one to two micrometer activated carbon colloidal material.

A lot of development went into making the colloidal material and that is a really basic definition is the homogeneous mixture of a micron size particle dispersant liquid. The impact in the field is that when you mix this material in And listening to Rob, he mentioned the word ink.

It does look like ink and it’s stable, which means it doesn’t settle like destabilized materials on the right. And it’s not just settling. A lot of these materials, if they settle, other forms of a pack or other materials, they can actually become hard or very viscous and hard to inject.

And so when we were researching this, one of the things that we did was spend some time at a lab at Colorado State University. This was a microcosm experiment that was done, now retired Dr. Tom Sale’s lab at CSU. But what we were doing is we were looking at a number of things.

In this experiment, we were actually looking at solvent remediation, but also distribution of our material, and I’m just gonna focus on the distribution side. And yes, what we saw here in a microcosm that was interlayered where we had sand separated by silt. And the silt is shown in the light tan color right here, if you can see my cursor.

And so at day two, when we started, we’re upflowing the material from the bottom, the PetroFix colloidal carbon. And at day 53, you can see just a really nice coating that is fully set. And in fact, what’s interesting is that because the colloidal material is so small, it started to actually forward diffuse into the silt.

And so you can see the silt layers right here are receiving through diffusion the one to two micrometer particle going into that. So that’s pretty exciting. And that’s a really great benefit of this is the ability to get a complete, I like to call it floor to ceiling, wall to wall distribution material.

And so the way we do that and the way that Rob approached it at the site was to use multi-port tooling that uses fixed open or retractable tooling that’s typically about two to three foot in length. And this is an image that I’ve used many times before that shows the typical tooling we use.

If you look at the tool on the right of the gentleman who’s holding them, that retractable tool is something that we push down to the bottom and then we pull back. We typically use a two foot length. You can buy these in one foot to five foot lengths. We typically use two.

You push them down the depth. You add pressure to them, 20 to 80 PSI, typically gives you two to seven GPM. Now, typically these pressures were not fracturing. They’re low enough that it prevents most surfacing. It does happen occasionally at Rob’s site. He had some of that. Part of that is the depth of groundwater.

At sites, the closer to the surface you are, that is a challenge anywhere. But typically we’re at really low pressures that help minimize surfacing. One of the big advantages is that when we do this and we use this tool on the ground, this is an illustration or an animation we’ve used in the past.

It’s a pretty forgiving distribution, particularly for sites that probably need more high-resolution work, could use more site investigation, but, you know, for budgetary reasons, you’re just not going to have that data.

And even if you had it, you might not always be able to find every channel or quarter the contaminants going through. PetroFix is very forgiving that way, even with sites with limited site data.

And I think that’s one of the advantages, is that because we can apply this so easily with a multi-port tool that spans an entire aquifer, the self-distributing nature of the material gives a gapless coverage as compared to, say, other forms of activated carbon you might be familiar with, such as PAC.

A pack typically goes in at several hundred to several thousand PSI. It forms thin fractures, which is not a gapless coverage. One of the challenges that can happen is pack can go in and train into wells. Interestingly, colloidal carbon has been shown through field studies actually to pass through wells as compared to pack, which will entrain into wells.

It ultimately results in the required replacement. So, the first advantage is to summarize it up is that colloidal carbon, even sites with limited site data, is a reliable, safe, and cost-effective amendment for remediation. So moving into the second advantage is there’s an advantage with the electron acceptor package with PetroFix.

I was inspired to talk about this a bit because just talking with Rob about the number of acceptors that were used at the site over time. Now albeit not together but in sequence over time and ending up with PetroFix. I wanted to talk about this a little bit.

So PetroFix is indeed the colloidal activated carbon and it comes with buckets of ammonium sulfate and sodium nitrate which are water soluble and they kickstart biodegradation which forms biofilm formation on the microscopic particles that are attached to soil.

These biophones, these bacteria that are growing, I think Rob did a nice job showing some of the gene targets that you can see when you do that, and it causes regeneration. And it results in the lifespan longevity of the PetroFix , so it’s very important.

I found an interesting question to bring up today or an interesting observation is that we talk a lot about our electron acceptor blend with PetroFix  as nitrate and sulfate, but you can get good results using pretty much any electron acceptor with a caveat.

This is a table that was provided by a client of ours that did some research on actually comparing the results over a three-year period of using four different electron acceptor combinations in a field study to just kind of determine is there a significant difference in different electron acceptors with PetroFix. And so just not going into a lot of the details, the four errors were used at the site.

Single plume four errors were used, one had nitrate and sulfate, it was the PetroFix package. One actually used ORC, now Rob mentioned using those as socks at a site.

Typically we’re injecting ORC in a grid fashion as a slurry. Also compared it by using gypsum. So this, that was a form of sulfate and then nitrate.

And what you can see here, over six months and 36 months, and there was a lot of great data taken, and I’m just really boiling this down quickly, is that all electron acceptors were actually effective in stimulating the biodegradation of BTECs, GRO and DRO, which is great.

I think we intuitively know this, but this is the first field study that ever showed it side by side. Oxygen was actually best short-term. If you look at six months, they were getting 99% reductions with oxygen early on. But in the long term at 36 months, the electron acceptor package, the nitrate sulfate with PetroFix, actually achieved a 99.5% reduction.

So, you know, everything was good. The nitrate sulfate came out on top, which is great to see. Gives us a lot of confidence with this.

But the one advantage of this is that PetroFix also is injectable with colloidal activated carbon, meaning that the amendments are designed to mix in the mixed tank and inject down the same with the geoprobe effort to create a grid or a barrier as compared to the other components. And actually Rob and I’ve talked about this a little bit.

And I can say that I’ve worked with ENTEA on a lot of sites and this comes up occasionally. But you know if you’re if you’re considering or have a background with other electron acceptors and you’d like to use them, you can.

The challenge is that divalent cations such as a calcium or magnesium, say gypsum, is a calcium-based sulfate product are not compatible in tank. They actually have a chemistry that can disrupt the colloidal nature of the PetroFix and makes it challenging for injection. It’s just not gonna be able to distribute the way we want it to do.

So keep that in mind, you know, I think most people use the PetroFix EA package. They get incredible results, as you can see here from the study. Long-term results are great, but you’re gonna be able to do a single injection, whereas what’s probably gonna be needed as a second grid to offset any other sort of divalent cation electron acceptor.

But they all work well and we’re happy to be creative with you. We work with Antea on different sites just to make sure they’re making contact and getting the maximum benefit of PetroFix.

And the third advantage for PetroFix that I want to get into and my final concept is that it has a really great treatment range.

Now, you know, Rob’s site that he talked about fits a common treatment range that we have, and that when I look through the data of, you know, the 1 ,300-plus PetroFix sites we’ve got, a large number of them are probably below 10 milligrams per liter for total betex plus TPH gas.

You know, this is considered a polishing range for a lot of people, but PetroFix actually has a wider range. We can put in a lot of material. And the graph that I’m showing you is a representation of a design philosophy that we at Regenesis have, that I have, as we look at different technologies and select them.

The concept is that on the vertical axis of treatment efficiency versus horizontal axis of containment concentration, there’s some technologies that are just better at certain ranges. For instance, if you have lots of measurable, visible own apple, you’re not gonna be using biodegradation per se to clean that up.

You’re going to be digging it out. You’re going to be using, say, dual-phase extraction. Or you’re going to be using air-sparging SVE physical. But as many of you know, when you turn off your physical systems, you get rebound.

And then you might be looking for something next. So ISCO is one of those as you transition down. The interesting thing is that PetroFix can actually be used on a site-by-site basis. We take a look at it on a wide range of sites, not just sites that are below 10 milligrams per liter.

We’ve helped clients treat sites with groundwater concentrations. I’ve seen some at 50, if not higher, and it depends. Are you gonna get triple nine reductions in benzene or quadruple reductions in benzene like we’ve seen on some sites starting that high, maybe not. But there’s a lot of sites out there, could be Brownfield, could be manufactured gas plant, could be a UST that really just wants to see a betterment of the product, they wanna see a reasonable reduction, prevent it from going off site, it really depends.

But there are sites where that PetroFix  might actually come in handy and replace some efforts that you might previously have been looking at with the sorption and bio package, not just trying to polish down to one PPB.

Now, this is a chart of the nitrate and sulfate electron acceptor blend of PetroFix from the table that I showed a few slides ago that was done in Canada. The reason I decided to show this is that, you know, leading up to the PetroFix application at 100 months, you can see that this site was typical.

They went through air sparging, SVE, and then when they turned the system off, it rebounded. Then they transitioned into Chem-Ox, which is a really common approach. They noticed that after they did the Chem-Ox injection, and it again rebounded.

And so one of the dilemmas is that how often do we run or how many ISCO injections do we have a budget for?

And what I’m making the case for is that PetroFix has such broad range is that you can use it not only for polishing, but this chemical oxidation injection right here probably could have just been done away with and gone in with a PetroFix application and gotten the same results. And you can see here that after the PetroFix application at about 120 months.

It’s been at non-detect levels now for the past 20 months so some pretty great results on that. So with that I’d like to wrap up and you know just conclude with those three points. I look forward to working with Rob and Antea. They’ve been a great client. We’ve had over 13 out of 30 sites worldwide.

I mean I’m excited to share as I look through these Antea is our number one user by number of sites across the world. They’re very creative I think ANTEA is very adept at what they do.

And then Rob’s side is not the only side that we’ve looked at, but I think there’s going to be a lot more. And I look forward to more case studies to come.