With that, let me again welcome everyone to today's broadcast
of the FRTR presents PFAS Emerging Characterization and Remedial Technologies.
This is session 1. I would like to introduce you to your two speakers
before turn it over to the co-moderator.
We will be joined by two presenters. First we will have Linda Gaines
who works here at EPA as an environmental engineer and environmental
health scientist. Previously she worked as a consultant performing
environmental site assessments and water and wastewater work. She has
been here in the policy branch in the area of human
health risk assessments and also maintains the Superfund chemicals
database matrix and regional screening levels. The majority of
her time is spent at Superfund subject matter expert for
PFAS. We then joined by a second presenter, Ramona Iery, who works
at the naval facility warfare Center. Sheet is a physical
scientist there where she has
more than 10 years of experience in the field of environmental remediation.
Her areas of expertise fate and
transport, site characterization,
launcher monitoring and remediation of contaminants like where needed
solid petroleum, and emerging contaminants like PFAS. She has been working
with PFAS for the past 5 years
in areas of site characterization,
granular activated carbon treatments, and regeneration and researching
remedial technologies. I want to thank both of the speakers for joining
us. I would ask Cindy Frenkel, if you are there
on the line, if you could come on and share a little bit of information
about today's sponsor and effort here.
>> Thank you. I want to let everyone know that the federal remediation
technologies Roundtable is the sponsor of this event.
FRTR has these meetings twice a year for folks come together in
the D.C. area from many member agencies including the Department
of Defense, interior, environmental
protection agency, NASA, and his folks all come together with
the mission to build a collaborative atmosphere to help
in hazardous waste site cleanup so we work
primarily with technologies and we are just trying to get information
out to other agencies and to the public about cleanup technologies
for hazardous waste sites. So the two presenters you will hear from
today are presenting materials that were delivered at a meeting late
in 2018. This one was focused on PFAS emerging
characterization and remedial technologies.
We will have another session coming up later this year also on that
topic. We will give you more information about
that at the end of today's webinar.
I just want to thank our speakers today for coming back and doing
this webinar and, if you are curious about what FRTR is up to, I encourage
you to check out FRTR.gov.
If you go to meetings,
it will tell you about what meetings have happened recently and are coming
up and those are open to the public.
I will hand it back to Jean Balent.
>> Thank you so very much. That's, I will go up
ahead and call it the presentation materials for the first beaker,
Linda Gaines. Whenever you're ready, feel free to begin.
>> Okay. Thank you. Hello. My name is Linda Gaines.
I work at EPA so good afternoon or good morning,
depending on which time zone you are in. I will give,
my presentation is what are PFAS's and what are
the problems with them. So let's see here. Here we go.
Probably you have heard PFAS before. It refers to
Per- and Polyfluoroalkyl Substances.
It is a group of thousands of chemicals. I tend to subgroup
the functional group. All of them, you will have carbons that are completely
fluorinated and some are in their that will be a functional group.
Most subgroups have ranges of chain length. Many
people are familiar with [ indiscernible word ] which is
a carboxylic acid with eight carbons.
Their art carboxyl acids that go probably
down to two carbons and they go all the way up to maybe 14 carbons.
I could not tell you the exact amount.
In other words, most of the functional groups have all these various
chain lengths. PFAS's are highly fluorinated. Their
highly resistant to degradation so both biological and physical
chemicals degradation, they are very mobile. Most of them are actually
surfactants.
They have varying and unknown levels of toxicity.
We don't even know the structures of all of them and we lack
a lot of information. One notes, you may have heard the term
PFB before. So some people probably still do prefer
to PFAS at PFCs which stands for per fluorinated chemicals.
One of the reasons that most of us have moved away from that term
is that PFC can also stand for per fluorinated carbons which are kind
of different of chemicals and are actually a refrigerant.
To avoid confusion, just so you know, PFAS and PF see C
can mean the same thing.
As I said, there are thousand different chemicals that are, in
fact, PFAS's. I brought up the chemical structures of a smattering
of different chemical. The top one is a carboxylic acid
it has a total of 14 carbons.
The second one down is analogous to [ indiscernible
word ]. This one is kind of used as a replacement for [ indiscernible
word ]. Is like it but it has two less carbons. I will not
go through all of them. You can see all of these different structures.
I will actually give you a pop quiz.'s no in your screen, you should see
a little box where you can answer which one
of these do you think is PFOA. You can say it's one of
those or maybe you think it is all four of them which are in fact
PFOA. Go ahead and take a moment and make a guess. Don't worry. We
are not grading you. Feel free to just go ahead and vote if you
are not sure.
>> We are getting some responses. I will give a
couple more second so pretend like you are on Jeopardy.
The correct answer is all of them.
The straight-chain molecule is what most people associate with
PFOA.
But in reality, because of the manner in which they
are being made, you can get all the different pretty types. So as
long as it has eight carbons and they are fluorinated except
for the one carbon on the carbolic solid acid,
that still PFOA. And in fact, literally yesterday, I was looking at a list
of different chemical, trying to get numbers and I believe
there were dirty nine different isomers for PFOA alone all of which
had these numbers. So there's a lot of them. Just so you know,
it's also important to know, with analytical methods, which
I will get to a little bit later, I got to remember
to talk about that, with analytical methods, be sure
with a letter telling you. I think telling you about straight-chain,
they tell you about the total?
What are PFAS
used for? Basically everything.
I'm only being slightly hyperbolic with that. They are used in
a wide variety of industries and a wide variety of commercial products.
Have, in fact, really viable properties like viruses, dust suppression.
So most people associate them with
AFFF to fight fires. They are also used
to make polymers such as Teflon. It's all
those varies stain resistant products, nonslip
type stuff. They've also gotten more industrial type application
like dust suppression for completing,
manufacturing electronics, a lot of different cleaning products,
industrial and consumer.
>> Unit PFAS universe,
what type of sites we might find them, again,
there's a wide variety of different interest trees like metal plating,
plastic, textile coatings, plastics, chemical manufacturing,
carwashes, many carwashes use PFAS in the different products
in the wax application.
It doesn't need to say that there will be contamination. It just means
that they are using them there.
Waste disposal, whatever waste goes in there,
there you go. And so if you have an online land, if
PFAS had gone in, you very may well have it coming out.
It will be in the groundwater if you don't have a lighter. And AFFF,
we sort of associate it with military airfields but
it's also with commercial airports, fire training areas, chemical refineries.
>> With releases, it's always good
when you do your conceptual site model, you to think about all the
different pathways in which the PFAS could be released. With AFFF,
where was it used and stored and tested?
Biosolids applications is a problem.
Biosolids can be applied to the soil and leach into the groundwater.
It can come out in the
leachate. I've also seen evidence it can out as
landfill gas. The more volatile one will
do that. Manufacturing, consider wastewater and also consider
air deposition. There are some PFAS that are volatile and
some that are not volatile still, like aerosols can come out the
stack and so that can lead to air deposition.
In terms of which specific PFAS we are
finding, I originally presented a couple of years ago,
I had it divided
up by AFFF and non-tran06 sites. I
decided that was not a good way to do it because it turns out basically
every single PFAS site I'm clear with
has a wide variety of PFAS. I've never seen a site with one and only
one PFAS. You will get the carbolic solid acids,
C4 to C-14 have the detected so basically what you look
for you very may well find so it is just important to note
what is your analytical method looking
for and know that you probably are going to find
a wide variety. Various media can be affected, groundwater,
soil. The surface water can be affected and if you get into the environment,
it can get into fish and we are always concerned about
fish, I think, and I put deer on here because
I believe it was Michigan, there was a deer advisory and
some of the PFAS, I'm not sure which one, it was
found in deer meat and the had an advisory for that. Honey
was a concern in North Carolina that currently the honey
was analyzed for the Gen X chemicals and they did find some
but, as I recall, it wasn't a large concentration and he would
have had to consume a lot of money for it to be of can
turn.
So what do we know about the toxicity?
Unfortunately, we know some but there's a lot of information out
handing. The EPA, the
there was a lifetime drinking water health advisory at 70
parts per trillion. The HA is based on the sum of PFOA and
PFOS.
The reference is the risk driver for most of the equation.
The Superfund office for EPA has
peer review toxicity value published in 2014
and [ indiscernible word ] has a draft
talked the logical profile out where they derived MRL.
There are draft values for an updated number and
also there is a draft value for [ indiscernible word ].
Various states have derived neurotoxicity values are risk levels were standards.
To discuss a little bit more,
if you are not normally involved with risk assessed, we have,
there are toxicity values that are derived and you multiply, you
put that into an exposure equation and that is are you get risk. So
that is important to note because, if some state, some states have
been using the
toxicity values and different exposure equations they come up with different
risk numbers or different standards.
These have somewhat similar toxicity and
the table in here to give you and allow you to look at the relative
numbers and how they compare and it is important to note that I have
noted that some of those values are draft. I did not cover them.
A lot of states have their own values.
This was just too sore to give a little intro of the
different values out there.
Currently we have method 537.1
for 18 PFAS intricate water.
They have updated it to now include 18 PFAS.
There are two ASTM methods, both single
and validated. One of them is for PFAS in non-potable water
and one of them is for soil.
Both of these used direct injection.
Time for another quiz.
You may see commercial labs running
what they call modified method 537.1 four analysis. How
do you think it is modified?
Do you think they modify it so they can run non-potable water
for soil? And they modify it for other because it only covers 18
so they're doing maybe extra one and how do they modify it to
include dilution or do you think it is something else or do
you think it is all of them or are you just not sure what they are
doing?
Not quite the majority of you think the answer is all of
the above. 20% to get his other media. Some of you think it
is an analyte and some of you think it's an isotopic dilution.
So in reality, I'm not quite sure there's a correct answer to this.
My thinking is the answer is yes and maybe and I really don't
know. I say that because you know they modified it
and put other analytes in a but the truth is we generally do not,
there is no such thing in reality is modified method 537 so you really
are not sure what they are doing.
They will hopefully tell you what they are doing.
You will be able to figure out if they are doing it for other analytes
or if you have done it for other media, but this is not anodized.
Is no real thing. To the point of all that is if you are using a lab,
have a conversation with them and what do they mean by that and
what exactly are they doing? It's more of just
currently we have in progress a draft
as W8 46 method 8327 four direct inject method of
24 PFAS in non-potable water's.
I'm happy to announce that this will be out for
public comment within the week.
It may be seen as early as tomorrow.
So it will be out for a 30 day public comment period.
So be watching out for that.
Okay?
There is as W8 46 method 8228 which is
solid phase extraction isotopic dilution method for 24 PFAS
in non-potable water's and also for solids. That is in the works.
We are working on it.
And finally, there has been work done on a draft
direct inject method for 24 PFAS in soils.
>> When you are sampling for PFAS, first
of all, PFAS are ubiquitous. You need to take precautions to avoid
contamination of samples.
There was a joke going around for a couple of years.
I'm not sure if it's still going around the priesthood everybody
is going to have to sample make it because everything has PFAS.
Your sons might have PFAS in it and if you are wearing your stain
resistant field boots or stain resistant checks, that might have
PFAS in it and it probably does and pizza boxes might have PFAS
and I'm so bug sprays are currently a no
no. So basically I cannot tell you we can use you cannot use. But be
careful. Look at labels of products and there are certain things you
just do not bring it to the field. Do not bring
into the field you are weather resistant loading and or waterproof notebook.
Those will likely have PFAS and cross-contamination. Note
that if you are sampling from existing
wells, they may have PFAS leaking components which could cause contamination.
They might have Teflon tape involved somewhere in there.
Consideration for personal care products and clothing is due
to potential contamination.
>> Challenges we have, I
work in the Superfund and whatever challenges it know PFAS is currently,
CERCLA has are substances however
CERCLA authorities can be triggered if PFAS has a threat
of endangerment to public health or welfare. PFAS can be considered
contaminant or pollutant.
You may know from the PFAS action plan that
we are working to designate PFOA or PFOS.
There are currently no MCL's.
There's an action plan about working toward a revelatory decision
on MCL's.
Finally, numerous states have derived their own advisories
and cleanup levels. So if you work in more than
one state, you need to pay attention to what your respective state is
doing and what kind of standards they have.
We only have, well, we, EPA, we Superfund to
a certain extent, only have final and
there are many draft values out there
and also many states have their own values. Currently,
EPA method 537.1 which is used for drinking water
is the only validated method that we have.
And as I said, we are working on others.
When you have a site groundwater,
potential for PFAS will differ
both by type and by length of the carbon chain. The shorter
seem to migrate fast. So if you have a mix of PFAS, the short-chain
PFAS might be at the leading edge of the plume and the longchain
might not have migrated as much.
Migration will depend upon the carbon content of the soil, especially
the carbon content. Also, for example, [ indiscernible word ] are volatile
but others can be dispersed by air as particular. Finally, ecological
update differs so basically pay attention to what your PFAS is
and what your receptor is.
More clean of challenges, for drinking water, groundwater
remediation, there is Granular Activated Carbon, ion exchange and reverse
osmosis, potential incompatibility with other contaminant
remediation to oxidizing, you've got an oxidation in there
for another contaminant that can actually lead to precursors being
oxidized to form more of the final PFAS. Finally,
with soil, for the most part, it's digging Hall or oxidation.
There's a lot of work being done with remediation methods.
There is still a lot of work that needs to be done. That is it.
>> Thank you. We've had a ton of questions coming in for you.
We will keep you busy for a few more minutes. The
first question someone asks is if the compounds are still in use
or hasn't changed much.
>> They are still in use.
It seems to be, there seems to
be a discontinuation of the longer-term, the longer chain
PFAS whereas before, they might have been using PFOA
so moving to the shorter ones. There does to
be of a change in the chemistry so for example if
you are familiar with the North Carolina situation, it is a different
PFAS chemistry from what I have termed classical
PFAS for lack of a better term because I do not think any of these
are new or old so PFAS in general. Spec is there
a relation in toxicity between the overall kind of generalization
like shorter chain, less toxic, longer chain, more, or can we make
any kind of conclusions like that yet? Becca the charter the chain
judgment the shorter the chain, the shorter the half-life in the
body. That part does seem to have an actual relationship. Of course,
shorter half-life does not mean it is less toxic. The information
we have right now is shorter change and to be less toxic the truth
is there so much we do not know.
When you get to the different PFAS like ethers and
the different functional groups, it's really hard to figure out,
it's hard to even draw any type.
>> We had some
folks asked how did we first find out about the risks associated with
PFAS like we did at first come to our attention and I guess there
was some sort of [ laughter ] >>
[ multiple speakers ]
>> I know you have been working on for a little while now. So how
long has this been on your plate?
>> Apparently a lifetime. I'm pretty sure first
[ muffled audio ] I remember when I first started working on it and
I was like what the heck are these things and I'd never heard of any
of this stuff before.
I think the first real instance of this
stuff hitting the news was the Dupont Washington
facility in West Virginia and if you look up Washington works
and see studies, there were a lot of studies done and
that was in the 2000 and what is a maybe 2004 something
and I know we had a provisional health advisory
for PFOA and PFOS and those came out in 2009 because of the situation
in Alabama and Georgia and I think it had to do with how it was being
applied and kind of after that, that is when it went back
to start doing more work on it and start doing more research into
this so but like PFAS, like the earliest known
manufacturer of a PFAS,
they have been used, I believe the earliest date
I have seen is 1954 for completing.
They have been used since, I would say the 60s,
for AFFF. So they have been around for quite
a while.
>> We've got a few questions about can we transport
PFAS. One listener asks, let's say you have a water by you
impacted by PFAS. If that water evaporates,
[ muffled audio ]
>> [ laughter ]
>> Based on the information I have,
the short-chain are more volatile and those are
volatile so probably will go into the atmosphere. The longer
chain one probably going to stay
in the water. The little bit I know some is that PFAS love interface
between air and water, between water and sediment
and their are surfactant
and they are between two different media.
>> Articles for PFAS are high soil compared to
water. Is that because of transport in groundwater so
something is soil or can you comment on that at all? Back in so when
you calculate the screening level, so I think
with the question is going for
when we calculate risk, for PFAS, it is solely about the
ingestion which is not to say
these do not have [ indiscernible word ]
but we don't have any values for
it so you're just considering the ingestion. So when you are looking
for soil, when you are looking at groundwater, it all has to do with
the exposure so if you are using
the equation for soil, you get incidental ingestion
of oil with a child and I think we assume children eat a
grandma soil a day or along those lines and I know as a kid I
it more but anyway drinking water, we a child
drinks 1.8 L of water a day so it all has to
do with how much they are actually adjusting whereas we do,
I know we calculate models both for
the actual contacts, the ingestion of the soil, but we
also look at [ indiscernible word ] of oil to groundwater
and I think those numbers are actually lower the only issue with those
is there some question about the actual migration parameters
like when you are looking at the specific physiochemical parameters
we would use, we need more information on those is
yes I guess where we are going to.
>> Okay. You touch on what kind of impact organic carbon
and soil might have on movements or transport of PFAS?
>> So what seems to be occurring is that PFAS loves carbon.
In other words, if you have a highly organic, if you have soil
with a lot of organic carbonated, the PFAS are
probably going to cling to the soil more tightly than if you
had some type of soil like clay
or something that has no organic content. It is probably going to
move faster.
>> Okay. I think we are going to close down session
of the Q&A with that.
One last thing, maybe later can tell us how to find out
8327 is release or where they can go for that in no.
>> [ laughter ]
>> I know it will be in the docket.
I'm not positive if a Google search
of 82 seven will work -- 8327 will
work. I'm not positive.
>> Said that should be a pretty soon,
right? It should be with the next week
or expect any day now.
>> Yes.
>> We will go ahead and add a link on this webinar for folks who can
come back to this webinar page and look at the related URLs I will
put only to the docket.
>> Okay. That's a good. Everybody, you have to come back.
>> [ laughter ]
>> Okay.
With that, we are going to go ahead and switch on over to our next speaker,
Ramona Iery.
>> Ramona, are you there?
Are you ready to go? Back in yes.
I am here.
>> Okay. Go ahead. Please start.
>> Thank you and hello everyone.
For the next 30 minutes or so, I will present
to you an overview of some of the most frequently used treatment technologies
for PFAS compounds.
We will discuss both water treatment technologies as
well as soil treatment technologies. Water
treatment technologies tends to be more pump and treat technologies.
We will talk some about the soil treatment
technologies before we wrap up.
This slide shows you ace Marie of some of the technologies
available for drinking water treatment.
These are mainly treatment technologies that fall into treatment
categories like sorption,
membrane filtration, coagulation, and redox.
When it comes to sorption, technologies include activated
carbon, anion exchange, minerals like Clays and also biochar.
The most frequently used technologies are activated carbon and
an ion exchange which are commercialized and can be purchased from vendors.
When it comes to membrane filtration, there is reverse
osmosis and nano filtration pick these have been shown to work really
well to remove PFAS from water and these are commercialized and can
also be purchased from vendors.
There's coagulation technology.
They are being studied by researchers.
I am aware of one that is available and
I believe it can be purchased. But these are less frequently used.
We have the redox technologies which include electrochemical
oxidation. We will talk about one technology that
uses oxidation that is currently under development. So you see there
are three technologies, they have an Asterix next to them.
Those of the three we will talk in more detail on today.
We will talk more about activated carbon, and
ion exchange, and electrochemical.
>> When it comes to drinking
water treatments, it is mainly puppetry technologies that we currently
have. Those can be applied at the wellhead. Those are typically
big systems and can be used at point of use and
to venture treatments. Point of entry systems are often installed
at home in the basement and you can see that in the picture,
the bottom picture on the slide.
Other than removing the PFAS from drinking water, these
treatment technologies can be used to control the plume
size and spread of the plume and also sometimes they are
used at the base boundary to prevent the plume from migrating off-site.
Currently when it comes to treating water and removing PFAS from
water, pump and treat are the most practical technologies for us at
this point.
>> Let's talk about Granular Activated Carbon for a
few moments. Granular Activated Carbon is often made from bituminous
coal court coconut.
You have probably heard of coconuts
carbon. It is highly porous, has a lot of surface area, and right
now, Granular Activated Carbon is the most popular and most widely
used. That is probably because it is the lowest cost but also has
a really high capacity.
It has been shown to work really well. One of the processes
to make this activated carbon, in terms of the mechanism,
what is actually happening when we expose PFAS contaminated water
to GAC. At that absorption process
on the surface where PFAS is pulled out of the water [ muffled
audio ] we do not have any transformation of the PFAS or chemical
degradation of the PFAS when we use activated carbon. It's really
just an adsorption process. We have seen that GAC has the capacity of
90% to 99% removal of PFAS from water. GAC works really
well. That is why it is one of the most frequently
used technologies right now.
Linda mentioned to you that there are maybe 1000 or
more different PFAS compounds.
Different PFAS compounds breakthrough GAC
at different times. That's one thing to keep in mind when you use GAC
to remove PFAS from water. The GAC capacity for PFAS is higher
than the capacity for PFOA.
When it comes to shortages, PFAS compounds tend to breakthrough
the GAC must faster so the capacity for shorter chain
compounds is less so that's important to know when
you are using these, when you are using this GAC. Also if
you have high organic carbon content in your water, that
may reduce the effectiveness of the GAC. Often a pretreatment
is placed on the system where you can remove your activated carbon
before sending the contaminated water the GAC.
>> Let's look at some detail we have here. I
mentioned that we have bituminous carbon and also coconut carbon.
What do the graphs show you here? It is a comparison
of how bituminous activated carbon or call works is compared
to the coconut carbon.
This is not a full-scale system.
It is a small skill system the pretty much mimics how a large scale system
would work. Let's look a little closer at the slides.
>> On the left, the
concentration of PFOA exposed to the GAC was around
900 PPT. This is shown in pink,
the EPA health advisory is 17 PPT
so the PFOA concentration is of it higher than
the EPA advisory. The coconut carbon is shown in green and
blue lines.
At the exit of the system, affluent
concentration in the green and blue lines families breakthrough
beyond the concentration just at about
somewhere between 1000 and 5000 is where we have
breakthrough in this is our coconut carbon. Looking out our bituminous
carbon shown in the blue line, we see breakthrough happening more
around 20.000.
In assistance with this water, the bituminous
carbon performed much better than the coconut carbon because breakthrough
in the coconut carbon just after about 2000 to 5000 bed volumes
and through of the bituminous carbon around 20.000
bed volumes. Let's look at one of the shorter chain PFAS
compounds,
PFBS. This is a four carbon compounded let's see how that one performed
in the presence of coconut carbon and bituminous carbon. The coconut
carbon performance is shown in green and put to minimus carbon
is shown by the blue line.
Much faster breakthrough of the short-chain
PFAS compounds to the coconut carbon here around 10.000 bed volumes
are so. The bituminous carbon, around 60.000
bed volumes before we saw breakthrough of this PFBS, a so in this instance,
we see that bituminous carbon performed much better than coconut
carbon. All of the data I am showing you today
is public the available and I have included the references on
the slides so if you would like to look at the data in closer detail,
I will have to just know the presentation.
On an earlier slide, and mentioned to you the Thermo reactivation process.
After you have used activated carbon to remove PFAS from your water,
you can actually have the carbon reactivated for use again.
How this is done which is at high temperatures,
it's done in a negative pressure in the nitrogen environment.
[ muffled audio ] to ensure that any PFAS that have not become paralyzed
just doesn't go into the atmosphere.
Using reactivated GAC has a lower footprint than
using the Virgin GAC. You can have your carbon reactivated after
it has been used to treat PFAS.
So far, it has to be just as effective as the
version carbon.
>> Let's look at more detail from an actual site. This is
the Navy base in Brunswick. This space had an existing dry work construction
to to treat volatile, organic carbons. This existing
treatment system used GAC to
remove the volatile compounds from the
liquid phase.
PFAS was found at the sites they use GAC to remove the PFAS.
So let's take a look at some of the data and how the system performed.
Take a look at the first graph to the
left. Were looking at PFAS concentration at
runs week. The blue line shows
influence concentration over time.
Effluents concentration is shown by the purple line
and also by the greenline. The greenline should
affluent at the midpoint and you can see we have not had any breakthrough
of the PFAS beyond the U.S. EPA health advisory
for pretty much the life of the system. We
did have a change out of carbon after about nine months or so.
That is because for the system, they decided to
change out when there was a break through of
PFOA but right now we are looking at PFAS so let's look at the PFOA
graph. Concentration is shown by the blue line and the EPA health
advisory is the solid blue line at the bottom of the graph. As
you can see at the midpoint that is after first vessel,
at the midpoint, we are seeing some breakthrough
happening here after about nine or 10 months, we are seeing
before breakthrough and then was changed where the lead vessel
was replaced and bituminous activated carbon was a. Immediately
we saw concentration go below the EPA health advisory. So
in this Tim, we see that they have coconut carbon in the leave
us on that what was able to remove the
PFAS and the PFOA holiday bituminous carbon in the vessel and both able
to remove the PFAS and PFOA and we did have some breakthrough
so they changed the vessel and the concentration was
pretty below the EPA health advisory.
One thing I would like to show you in the slides, I mentioned
the high talks unit which was advanced oxidation process.
Some of you may be aware or heard in history
that advanced oxidation does not really work very well to our that
I these compounds and it's not really a technology of choice
and take a look at the affluent P4 and P5 units. It's shown in
red on both grounds and it
mirrors the insulin concentration. So this
confirms to us that advanced oxidation, not able
to remove PFAS or PFOA from the water, [ muffled
audio ] pretty much the same, mimicking
the concentrations.
Let's look a little closer at PFOA.
I was showing you before the entire system and this is just the carbon
vessels.
Here we have the insulin concentration,
sorry, that's affluent concentrations.
The advisory is shown in the solid blue line. Our affluent concentrations
of PFOA is shown in
the greenline.
Noticed that after some time, we start to see the affluent concentration
increasing and then it goes beyond the health
advisory that there was a change out of the vest all, change out
of the carbon, and we see the concentrations decrease back down below the EPA
health advisory so this is just PFOA concentrations coming out of
these carbon vessels.
As soon as we do that change out,
concentration decreased. Let's now look at
four carbon chain PFAS compound.
The affluent is shown in the blue line and
the affluent is in the greenline and the midpoint
of the system in the greenline and at the end is
a purple line a notice we have concentration are pretty low but
start increasing. We don't have health advisory
so we are just looking at what is happening to the concentrations.
The affluent concentrations are increasing both of the midpoint
and at the end of the system. And you may look at this and say how
can the affluence of the system have a higher concentration
than the influence of the system.
During the presentation, she mentioned to you the possibility
of the cursors and precursors converting
to PFOA and PFBA. Might be why
we have PFBA higher at the influence.
The maybe oxidizing precursors to PFBA increasing the concentration
of PFBA so it's very interesting data you're showing what can happen
to the different PFAS compounds on the carbon and
the high talks unit.
Let's talk about ion exchange a little bit.
This is a synthetic cereal that is used
to remove PFAS compounds.
It can be single-use or regenerated. This
is how the vendors sell the ionic exchange resins. tends to
be an exchange so the resin
would lease a negative charge ion.
Often in a lead leg configuration. Mechanism is
an ionic change until adsorption.
The graph to the right different PFAS compounds
see the ion exchange does work better
than GAC. Keep in mind that it is more expensive.
When using ion exchange, keep in mind that
you have to know what is in your water pretty well and
what kind of ions are there since this is ion exchange mechanism
because you may have competition for different ion for these active
sites. You may have competition from core contaminant,
organic matter befell your resin.
So it is important to do so all scale bench test before you actually
implement a big system. So you can see how your specific water performs
with this ion exchange resin.
The ion exchange resins can be single-use or they can be
regenerated. So there has been some things done
by different ion exchange vendors on actually regenerating ion exchange
with these fine solutions and also alcoholic methanol and ethanol
to try to distort the compounds from the ion exchange resin
and they have had some success with these solvents and also with
chloride. Just be aware that you may have to adjust
the resin and you may be able to send it back to the vendor for
regeneration. Let's look at the case study where they compared
activated carbon to ion exchange.
This shows you concentrations
and take a look at, let's take a look at
PFOA and PFAS concentrations.
PFOA averaged about 12.000 ppt and
PFAS averaged about 26.000 parts per trillion which is much higher
than the EPA health advisory of 70 PPG. We have
some very contaminated water here.
The system was set up with for GAC columns and the ion exchange columns
as we see here in this figure.
There are just a few pictures of the system, the GAC system
let's look at how the two systems performed.
The influence concentration of PFOS
is about thousand PPT before [ audio cutting in and out ] 10.000
PPT of PFOA. The EPA health advisory
shows in the dashed red light. We would like to stay below that health
advisory level. That's first GAC warmed. There were
multiple GAC level.
The lead is shown in blue. The lag is shown in yellow. Notice we have
breakthrough above the EPA health advisory at around 5000
for the lag and even maybe around 2000 volume
for the lead system.
When we look at the ion exchange resin which is shown in the lead
shown in purple and the leg is shown in green, notice we did not do until
maybe 15.000 to 20.000 that volume in the lead system and
select system, after 20.000 bed volume, we still do not see
breakthrough. In this case, GAC did perform better
than ion exchange resin for PFAS. Let go look
at PFOA. Influent situation was about 10.000 PPT.
Our affluent from the GAC which is
shown in blue and yellow around 5000 to 4000 bed volume's we start
seeing breakthrough. For the ion exchange resin, the breakthrough
is happening here maybe around 8000 bed volumes are around
12.000 that volumes. So the ion exchange is performing better than
the GAC in this let's
take a look at a couple of shorter chain carbon
GAC in both census,
we saw higher concentrations in the affluent sooner
at the lower than volumes. So again, the ion exchange resin is performing
better even for the shorter chain carbon.
Some regeneration was tried with the ion exchange
resin. As I mentioned to you, they use a brine, some alcohols
to regenerate the resin.
Then both version and regenerated resin were tested. Notice that
the bed volumes treated by the Virgin in the purple line and
regenerated resin in the yellow line mimicked each other. That lets
us know both the version and regenerated
ion exchange resin performed very similarly to each other.
Just a summary of this case study, both the GAC and ion exchange were
able to remove the PFOS and PFOA but it's very
clear that the ion exchange resin performed better than the Granular
Activated Carbon.
Just a couple of other technologies here, what technology on the market
is a colloidal activated carbon that is being marketed
for in situ to remove
PFOS from water. This is being marketed. What happened with this
is you inject it and those the service of the soil and then as
the contaminated groundwater flows past, it stopped
the PFOS. It is not a destructive technology
but it immobilizes the PFOS employees and they have been, there
have been a few field trials currently in the U.S..
One of the technology I mentioned is electrochemical oxidation technology,
this one is becoming a little bit more popular.
There is one that was patented where
the PFAS compounds are oxidized using electrochemical oxidation.
This can mineralized for ACH carbons. So the PF ES
all the way up to PFAS and PFOA, I do not believe
this is currently commercially available but they are working on
it. So not only can be used to relieve remove PFAS from water, it has
been test did on solutions from ion exchange resin
also PFAS impacted wastewater be aware that
this technology may be coming up to the forefront more at it is
commercialized.
Now we will in the next minutes or so talking about
some soil treatment technologies.
PFAS is not considered hazardous
in landfills. You can pretty much
go to any nonhazardous landfill.
However, all landfills will not accept that waste. So that
is one thing to look into.
Some are worried about future liability and
leaching so before you attempt to take your PFAS contaminated oil
to a lentil, check if they are willing and able to take it.
We have used in situ stabilization for other contaminants.
And now there are some technologies out there that allow
you to use PFAS compounds we stabilize your
PFAS compound in the soil so that it does not leech. Was developed
overseas. The technology is available in the U.S.
but has been developed overseas and use more overseas.
>> Aluminum hydroxide absorbed PFAS in soil.
Fighting occurs as fast as a 24 hours and it
has been tested for water treatment as well.
What happens here is it is an absorption process.
Let's look at a small case that he was a doing an
airport tax way and they had about 900 tons of PFAS contaminated
soil. Let's see what they did at the site. Excavated
900 tons of PFAS contaminated soil which had concentrations of about
5.7 milligrams per kilogram.
This cartoon of this guy looking at the soil is how we
all look at our PFAS sites like I have PFAS
contamination and what am I going to do with it and so let's see what
they did at this site. At this site, they took 900 tons of soil and actually
took it to a landfill. But what they did at the landfill was they
dug a very specific barrier so for this contaminated
waste. With the is the lines that sell.
They lied the landfill so with
some Rembind before the place the contaminated soil in the cell and
covered it with the Rembind. They actually did this
in the landfill. You can see in the pictures here, you can tell
there's all this trash everywhere but they dug this so in
the landfill and put aligning of RemBind and
covered it with RemBind as well.
This was done in Australia and they are
compliant for soil leachate of the treatment
which is about 0.2 ug per liter and they are monitoring concentrations
which will always be low at 0.2
so they consider this a success.
I have to think Richard Stewart for providing
slides. How much does this cost quite you look at the cost and convert
them into U.S. dollars and comes out
with everything, landfill fees, any interest geishas, bench trials,
it comes up to about $117 per ton.
It's not an insignificant cost.
Was done within the last 5 years or so. Cindy's our relevance
cost numbers.
At the site, they check to see, this is now another case that he,
they check to see can RemBind be used to treat water contaminated
with PFAS compounds. At this site, they had to full-scale
GAC systems. They decided can RemBind also remove PFAS from
water.
They set up a 30 gallon batch reactor
would tell 30 gallons of water.
They added the RemBind to this tank and let it sit for 24 hours.
At the end of 24 hours, they decanted the treated water
and added more contaminated water and it is for about two weeks,
treating about 280 gallons of water and monitoring for both
PFAS compounds as well as TOC.
Let's see how the system performed. Looking at the graph, we see
pretreatment concentrations of PFAS over
the time period from about maybe
2000 to about 4000 PPT.
The removal percentage by the RemBind was about 19% or higher. RemBind
worked pretty well to remove PFAS from water. You
can see the absorbed mass in the lower graph. It did much better
with PFAS absorbing a lot more PFAS than it did before.
To summarize what we talked about here today to ensure that we have
a few minutes for questions, GAC is used a lot of people consider
it the only practical treatment for groundwater two days.
Signed presentation that we can use ion exchange as well as GAC
and ion exchange performed better than
Granular Activated Carbon and bituminous carbon actually performs better
than coconut carbon in the studies that we saw. Ion exchange resin
is that of it keep in mind it is more expensive. There are some
in situ human technologies being developed.
Here are a few references. There are also references
on this I and you can see the reference and where the data came from.
That's it.
Taste was given by my coworker at FRTR a few months back
so I put mine in his contact information in case you
have any questions beyond what is discussed today. So shall we have
some type of questions I will wrap up now and see what you guys
have to ask.
>> Thank you. Yes, we've had plenty
of questions coming in. I don't think we will have time to get through
all of them. We will give you a few. First, let me back up four
minutes. Someone asked if GAC efficiency is affected by water
hardness. Can you talk about that a little?
>> I have not heard that it is affected by water hardness
I can see resins being affected by water hardness because of the
ions in the water. But that's not that I know of with GAC.
>> I think you probably touched on
this spec earlier in your presentation about what the sorption capacity
is for GAC with PFAS compounds. Can you discuss that
little more?
>> It varies by PFAS. It
has a better capacity for PFAS and it does for PFOA and probably
PFBS that it does PFBA.
So the capacity varies by compound and also
based on your water chemistry. So it is recommended to a small-scale
test.
You can have the vendor do this small-scale test and let you know
how your specific water chemistry will perform
in the presence of GAC in terms of removing the PFAS. So it varies.
It's based on a few different parameters.
>> Okay. You.
When you were discussing ion exchange, can you talk a little
bit about how concentrated that we stream from
ion exchange regeneration is?
>> That would be a pretty concentrated waste stream because you are actually
pulling any PFAS that gets absorbed onto the resin into
the waste stream. You are using, they are using the brine or the
methanol so it would be a pretty concentrated waste stream and
they looked at two different technologies to break down the PFAS
from the waste stream.
How would you say ion exchange compares to GAC as
far as, can you discuss
and compare?
>> In terms of the development of the ion exchange, they actually
are making the ion exchange resist the GAC, I'm not too sure,
but right now, they can regenerate the ion exchange so you can extend
the life of the ion exchange. You are not
replacing it as often. So you are using it longer
and then you can also regenerate it so that definitely help with
the sustainability. There's single-use and we general
and it would be more sustainable and allow you to use
it much longer.
>> Is one of these methods significant more expensive
than the other or is that usually a big component of the decision
of which method to go with?
>> The resins are definitely more expensive
than GAC so that's something to look into. You work with offender
to figure out what sizes to choose and how much, how
many pounds of resin or GAC you need to put in your system to help
you make that decision. We can also advise on how frequently
we have to change out so then you can do the financial comparison.
>> Okay..
We've got a handful of other questions in here, they are
still pouring in, but let me. Do you think we have time for another
couple of questions?
>> Yes. It's trite to do two more if we can.
>> Okay. Do you know of any other course
materials other than GAC that are in consideration for commercial
scale deployment right now or are there any others that you have heard
about that you think may have some promise?
>> People are experimenting
and other minerals to remove PFAS from water but right
now GAC 's number one. People are, if you look at the research
as we start looking at different minerals to remove PFAS from water.
>> Okay. Maybe we'll more about that in the future.
Someone asked, I'm not
sure if they are talking in situ but the asked how effective thermal
is for PFAS soil.
>> Thermal actually works pretty well
and I have been involved in some small-scale studies PFAS
from soil using thermal and it seems to be working pretty well
and there's a lot of research going on right now on that. There are
a couple of systems, couple commercially, systems that you can bring to your
site, add your soil to the system and thermally remove the PFAS. There
are some concerns with what is actually coming off
and what is apologizing off of the soil and can learns about
[ muffled audio ] and how you actually would treat
your [ muffled audio ] that I would say
thermal works. We seen it work with the soil concentrations are down
by 90 something percent of using HRML at concentrations
above 600°F and you can go up to
1000+ degrees Fahrenheit and yes it does work and it is however
under more research to really understand better what is apologizing off when
you do add that amount of heat to the soil.
>> Great. Thank you, Ramona. I think at this point we are going
to wrap things up. I do want to remind you that this was only the
first of the series on this topic.
There is definitely plenty more to say about PFAS
pick we will have another upcoming presentation later this year that
will include two more talks by presenters from the
FRTR meeting. This will be September 26 and you can register for that
now if you go to that link. We will have two speakers, one will discuss
pacifically more of the considerations
for when you are sampling for PFAS both in the lab and out in the
field. So if you are interested in that,
please come back and check that out and next I will pass
it over to Jean for more reminders.
>> If you are interested in participating
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