things over, to your session moderator, Cindy Frickle from the
EPA's technology innovation in field services division. Cindy?
>> Good afternoon. Can you hear me? We can.
Thank you. Today, we will enjoy presentations from a Mike
Truex, of Pacific Northwest national laboratory, and also Mark
Bricka from Mississippi State University.
So I want to give you some background on the
federal remediation technology Roundtable, the FRTR was established in 1990
to build a collaborative atmosphere between federal cleanup managers
and other remediation community representatives.
FRTR primary goals are to share information and learn about technology
related efforts of mutual interest, discuss future directions of the
national meter is -- remediation program, interact
with similar state and private injury -- industry programs, and
pursue subjects of mutual interest.
The FRTR member agencies include the department of defense, Department
of energy, U.S. Department of Interior, environmental
protection agency, national
Aeronautics and space administration, Institute
of health, and the nuclear regulatory commission. Today's
webinar feature speakers from the most recent general meeting of the
FRTR's answered by the U.S.
nuclear regulatory commission it was held at the headquarters in
Maryland this last November. The meetings topic was remediation technologies
for Radionuclides and heavy metals in soil, ground water
and sediments. The meetings objectives are listed on your screen,
identify and discuss existing and new innovative remediation technologies
with their technical basis and to share experiences
and lessons learned in the application of
these technologies.
>> So
after this, I will turn this back over to Jean
Balent. A right thank you so very much. We are going to start with
our very first presentation today, I first speaker will be Professor
Mark Bricka who is coming to you from Mississippi
State, Mark if you are on the line please feel
free to take yourself off of music and begin.
>> Okay, I'm assuming everyone can hear me correct?
We can.
>> I have a presentation that is really an overview
it says heavy metals in soil and water
but I will try to cover most of the technologies and we will talk
a little bit about organics as well.
My presentation is an overview of the technology. First
of all, what is environmental remediation? Those
people with 20 years experience of course of this very well, those
who have one may or are just getting into
it. It is removal of contaminants from environmental media. Who knows
what you have out there, basically there
is soil, groundwater, surface water, I include sediments because formally
I worked for the U.S.
Army Corps and that was one of their big focuses. But the purpose of
this is to take the media, and to either remove or
stabilize or isolate those contaminants from the environment and
prevent them from contaminating the
environment overall.
>> So I wanted to go over a few case studies just to bring you up
to speed, I guess one of the more famous sites at least that I am
familiar with is the Rocky Mountain Arsenal. I am assuming the audience
has maybe heard of this, or probably has run across
technologies use their. It is a site that the Army
actually operated they made chemical weapons and then they
sublet that to Shell chemical produced pesticides. So the type
of chemical weapons were GB, VX, they had blistering agents
as well, as well as nerve agents such as lewisite and
mustard, and then shell made the things on the
list, Aldrin, drilled in, and Eva
gone. This site was located near the city of Denver, actually
from the site you can see Denver. And the old Stapleton
Airport actually extended into a part of the
facility which we turned over to the airport it was cleaned up.
The facility is about six miles Bice X miles it is a pretty large
facility it covers many acres and one quarter of
that site, the northern corner, is
shaved off, and commerce city actually is
located downgrading of the facility. The contaminants that
were at the facility were everything known to man. You had metals, organics,
VOCs, pesticides, and agent related compounds, something known
as damp, which is specific to nerve agents after it
is demilitarized. The site is fairly large there is everything known
to man out there, it is pretty interesting. At
least for environmental remediation.
If you were on the lawsuit sites, it would keep you busy for years.
>> Some of the areas most notable, at Rocky Mount Arsenal,
include basin F, and actually there were basins letter a
through F, basins letter a, B and C, the materials that were stored
there disappeared. It basically leeched into the groundwater,
and absorbed into the soil, and so these areas were heavily contaminated.
Basin F, which is well known, out there in the environmental remediation
community, stored a lot of the
the military -- demilitarized waste, it was a quagmire
and since it was [Indiscernible] is stored
this material. The cell plant area is where they manufactured
the munitions, there was also the GB plants where they destroyed
the munitions. So there were many areas and then they
had the lake system out there. Which consisted of several lakes. I have
a picture there, of the lakes, I am missing my point
a hold on. It is
not there. We have the lake system, the technologies that
he used for remediation -- that they use
for remediation I went back and looked at the history, I believe
that some of the first story walls, which were put in place
to maintain contaminants were used out there, I went back and
looked in the northbound system was established in the
early early's -- early 80s and late 70s, there was a story while
where they cut off the water flow, the groundwater flow, down to the
commerce city, so they placed that to maintain
control of the water and keep the contaminants from moving down gradients.
>> Other technologies that they had out there, one of the first
deep well injections for habitus
-- hazardous materials, where they were injecting basin F deep into
the stratus, they open that up in the late 50s early 60s, and I continue
to operate until they have the trimmers in Denver,
and they tracked it back to the deep
well injection and two things that happened, they lubricated the fault
and pressurized it, so basically Denver started to have these tremors
and EPA said the Army needed to cease and
desist from the deep well injection, and that well I
got involved in that a little bit was closed in the late
1990s. The early 1990s. Another interesting thing, in
basin F, the waterfowl, it was a major flyover
area for various waterfowl, we had ducks
it would land on basin F, because it was a beautiful
area from the air, because it was a dark black and
reflected the sky and the clouds so it looked like a great place,
a beautiful lake. The ducks would come in there, and would never take
back off. So we put the
air cannons out there to control the population but it made it difficult
to work with all of the cannons going off all the
time. We also have you bionic play, with prairie dogs that were everywhere,
and these prairie dogs would have the fleas
on them so we had to be careful about that as well.
>> This area, was notoriously contaminated, very large
area, etc.
But then, and now, it has been changed into
a wildlife refuge, there is pristine, not pristine conditions
but wildlife bald eagles, buffaloes the room the
area, etc., basically although there are areas that there was a fence
but around, that said do not enter this because of the common
-- contaminations, most of the site at least on the surface was believed
to be fully remediated.
>> To the best of the ability of the technology
we had at the time. Another area that
I wanted to discuss, I case study was the small arm firing ranges,
some of you may be familiar with this or not,
the military and also private ranges there is a lot of lead that goes
downrange. Basically that is its intended purpose, you take a munition,
you shoot it from a rifle, or a pistol, and he goes downrange,
goes through target impacts the berm a safety berm.
That berm, is made to store that led and that is not
a waste, in a way it is worded now, as soon as contamination
or lead leeches off of the area, that you go into to
remove that lead, then it becomes a wasted has to be handled. The
problem is, many of these areas were
politically sensitive. The military had a knee-jerk reaction
for example, down in Arizona, one range that basically
got the limelight, they say go down there and let's develop some
technology and demonstrate to them.
I just had some heartache with that when I was first involved
with this, and I said wait a minute, first of all, is that
really representative of all of these ranges that we have out there?
We knew that we had literally thousands of rages.
And is a desert environment representative of what we have out there?
And two, this is an area that is less mobile because we do not have
the water that contacts the materials it probably is not representative.
>> What we did, we went out, and
I took all of the range data that I had, overlaid on a map of the
United States, so we were just looking at
facilities, then I took a soil map, of
surface soil, and put that on top we found that the Southeast was
our major area where the ranges were located, and we should target
those for study. So, what we found, when we were doing
this study, indeed we did have a lot
of contamination simply from the lead
that was fired out there. Here is a picture of the facility, and you
can see the lead Matt the forms on a
firing range, so there are literally thousands and thousands of bullets
going to arrange. But at these larger facilities, we can have up
to 1000 lanes at a particular firing range at a
particular site. It can be quite a lot of lead
coming downrange. But what we found, not only do we have the
particulates, and they are pretty easy to remove,
with sieving and physical separation remediation techniques, you can
take the bullets out, but due to galvanic corrosion, the bullet
is coded or jacketed with copper, the difference in the
lead in the copper causes the lead to become mobile, a
+2 phase, that migrates into the soil. And groundwater, and service
water potentially, but really that small fraction of the soil tends
to absorb that. Through the absorption the
finds of the material have a larger but -- fraction of the lead,
it becomes mobile simply because of the fact that he could be transported
off range.
>> There is a firing range, is get back into remediation technology,
we have really two types of technologies we
have those ex situ technologies, where we have to remain the contaminants
-- remove the technologies -- contaminants, and in situ where we tried to remain
it in the ground water and
the soil.
>> We have a number of technologies that we can apply to this, I'm just
trying to talk about some, to give some highlights. I can't talk about
them all. There are things such as big and tall, water treatment,
dialogical treatment, Fido remediation, electric kinetics, and
many others. I will try to highlight a few
of those. The state of
development of these technologies can be in
various states of development, one is we can have existing technologies
for example dig and tall. We have emerging technologies such as
electric kinetics, where it actually has been demonstrated
and used at some sites that on a limited basis. And
then we have innovative technologies that best when I could
think of is the bio refinery where we are trying to make products out
of a hazardous material.
>> So dig and tall, everybody that has been out there
for years, or has any experience knows that basically is the most
used technology, you go out with some type of excavation equipment,
you dig up the contamination, you basically
put it in a dropbox, and then you have to haul it off and you usually
put that in the landfill or maybe on site in the solid waste
management unit. The problem is, it only transfers the
contamination from one location to
the other. Hopefully we have done a better job where we placed it
then where we dug it up. But you still have a long-term
liability for the potential for contamination to migrates they continues
to remain with that waste. It is relatively
low-cost, but this depends on many factors out there. If you are going
to apply the manufacturers.
>> We have containments, containment can come in many colors, there
are landfills, slurry walls, we talked about that
with Rocky, solidification and stabilization, where we actually
treat the waste and then try to store it somewhere, and these that
are used by DOE for vitrification, were return
the material into a glass type products, and calcination where we
have taken the liquid waste or partially liquid
waste and try to make it solid.
>> So landfilling, those that have been out there in
the industry know, typically at least for hazardous
materials, we have subtype C, and subtype D facility, a
D facility is where the municipal waste tends to be carried
off your garbage from your house, subtype C is actually a
hazardous waste lined copiously lined, and monitored and
you have Leach A collection and you have that in
D as well. It is not on the same type of steroids
that we put the sub type C. Here I have a landfill showing,
on Jerry Island, is quite a large landfill, and then
over here is the lining construction associated with that's. I'm assuming
that many of you are probably familiar with this. We also put
daily cover on each of the lifts, as we put material in
the landfill, so that we do not get fusion
of omissions, and then it is capped, ultimately when that landfill is
filled, and the drainage layer is put in there to make sure that we
reduce the amount of water infiltration. If you are interested,
the EPA has the core put together a model
called helps, and it does a water balance around what would permeate
through the landfill, and wind up in the Leach, versus
runoff, it was prepared by Paul Schroeder. I
can put you in touch if you're interested.
>> Slurry walls, basically what we do here, with the slurry wall,
you take a backhoe, or some type of piece of excavation equipment,
you dig a trench, and you place a slurry into
that trench. This can be composed of bentonite, clay material, most
of those have very low permeability and are
swelling case, -- clays, you can also put other additives, what
we are's plea trying to do is to establish a low permeability Sloan,
the groundwater will not go through -- place, where the
groundwater will not go through.
>> In this case they are putting the slurry, this is keeping the
water from this dam from passing through to
the lower side of the dam. There is quite a head on that.
Solidification stabilization, I started working on this
for EPA for the land found proposal, even before
that with the studies that was, the interference
that he. And we look to material that would interfere with stabilization
solidification. Basically, what it involves, that you take a puzzle
on Nick or [Indiscernible] material with additives, you add
this to a semi-slurry, or
liquid, and that it becomes a solid.
Solidification is the fact that you may form
a monolith, stabilization is where you have a reaction with
the contaminants, and the contaminants are no longer mobile because
we had maybe a phase change or a speciation change. You have two
lines of defense. We can reduce water
infiltration if you form a monolith or block of concrete as you think
of it, that way you have particles that would be less
likely to move, and then you have the chemical stabilization
of that that happens. This can be conducted in ex situ or
in situ, and typically lime, fly ash, Portland, observance or Haddad.
Mixing is critical. -- observance or Haddad. Mixing is critical. This
is done in situ, it is fairly crude.
>> Next is vitrification, this is a technology
where we put electrodes into the ground, potentially, at a high
voltage current, that is done in situ, you have to collect be
off gas, if you have volatiles that will melt the soil, if forms
and obsidian like material, and the
problem is it is primarily used for nuclear waste simply because
it is very expensive, it is very impermeable which
is good, but it does have some limited permeability, and shelflife but
it is very life -- long. It is energy intensive
so is very
expensive.
>> Also, the volatile collection system can get
quite elaborate, and therefore also increasing the cost.
Calcination, is pretty complex, as a process, I put this up to show
you that there is a lot involved with
calcination, and again it is mostly used for radionuclides.
Bump -- pump and treat technologies, beside the stabilization,
this is probably one of the number one technologies that is used
out there.
>> What you do is you put in the slurry wall, or a dewatering
well, around the slurry wall, or you don't have to have the slurry
wall and you pump out the contaminated groundwater. But
then that requires treatment so you pump it out, it
is in that you, at least for the Pompey Park, and then of
the treatments, would involve all of the technologies such as
stripping, neutralization, membrane treatment, ion exchange,
electro chemical type treatments such as electrode dialysis
or electrophoresis, flotation, which is a mining type treatment,
electro winning, and you have filtration, you can throw a number of technologies
that that groundwater.
>> I focused on electro winning
just because it is less known as a technology, basically, it is just
like electroplating, we have the liquid and I'm trying to play
the metal onto the plates, and it has to be charged, so
I put a current across there, IDC current and pull those
metals out.
>> Physical separation, we studied this in a has been
studied extensively, we are really robbing technology from the mining
industry, they've been doing this for years, just like panning
for gold, that is the physical separation technique, where you
take a water slurry, and you slurry the dirge, the heavies fall into
the been, they stay there and you toss out
the lights. But there is more specific --
sophisticated ways, tabling, flotation, classification,
they had these big spiral separators that look like waterslides, and
you take your slurry and run it down the water slide into
centrifugal force with the slide.
You can actually have separation. Trammell's are
big seals, you can also use magnetic properties of soils to separate
those, you can also use density, various liquids with
different specific gravities will help separate materials
is ugly. The problem is that -- physically. The problem
is that many of these are extremely toxic, I don't if anyone has experience
with this but it has lost favor because the toxicity. And then you
have soil flushing or washing, which is intentionally applying some type
of extractive into in situ into the groundwater or
soil, and trying to remove those contaminants and get them out of
the soil.
>> Other remediation technologies, heap leaching, is one,
this is used in the gold mining industry where they take a
cyanide solution, sodium cyanide and they sprayed onto large piles
of war, and then basically have a collection system and tried to
collect the lead shade it comes out. Hopefully that is laden
with gold or the metal with the contaminants of estrus. And then
-- of interest and then you subsequently have to treat that. If I
told remediation, -- you have Fido remediation, you can have
a tree with a root system that will pump the contaminants up into the
leaves and then it can [Indiscernible]
or concentrate into the plant itself, the metal is usually staying inside
the plant, the problem is the plant would have to be harvested, and
the disposed of a lot of times by incineration. And
that tends to concentrate the metals, and the
fly ash, and that will require some type of disposal or
treatment. If you put that in the landfill, then you concentrated
that, and increase the potential of leaching.
So you were chasing your tail. And then you have
supercritical oxidation, supercritical water extraction, these
technologies can actually go in and extract the contaminants. And
then absorption and
adsorption, both of those I call them adsorption you can use
those technologies to contain a contaminant. There is a
newer technology, one that is less frequently
used it is freeze crystallization you can drive the contaminants out
of the soil. And then electric kinetics
is one of my personal favorites and I've done a lot of research
on that and I talked about that.
>> Electric kinetics is a technology that a lot of
times is targeted for in situ use, it can be used exit to but it is
less cost effective. What happens in a normal system, when you pump
and treat you got clay zones that is where your contaminant
may be held, and your contaminant with the water
that you are pumping due to hydraulic radiance will move around these
clay zones. With electric kinetics we get more of a uniform movement
through there, it is really effective with low permeability material such
as clay with about
[Indiscernible] permeability.
>> The way this works is we have a lecture migration
which is actually the movement of the metals due to the electrical
charge and the charges associated with the metals, you can have
electro osmosis where you can actually move the waterfront through there,
and we have electrophoresis which is particles because
it is in the soil they tend to be filtered out, you also have a pH
front, that you can control. So this is quite effective
if you are extracting metals, you can drive the soil pH down,
and reverse the charge on your electrodes and bring that back
to neutrality.
>> One of the interesting things that happened with
this technology, it was actually used extensively for the dewatering
of dredge material, early on by and hear my. --
the core.
The lite that they had, the water during the extraction was extremely
contaminated with metals and they said oh my gosh we don't know what
to do with his extraction.
This is not a viable technology, it took us about 20 years later
to say we can maybe use this beneficially. 20 years later,
we finally got back into the business of electro kinetic treatment,
one of the studies that I am familiar with, was at that point
the goo, at a weapons station, there was extensively
disposed of, into these ponds the you see here and
we did a six for project
for DOD it also was a site demonstration project, I don't know
if they even still have that program, but a Superfund innovative
technology demonstration. And ES TCP which many of you are familiar
with. All three of those funding mechanisms came in to look at
this technology, we went out there and put in the electric
kinetics system, that you see, we actually had a firm called Lynn
Tech that originally operated this, and then later was taken over
by the Army Corps. The problem was,
that it moved very effectively, the chrome and the cadmium out of
the pits, but the problem was there was at
the lien co-mingled with the contaminants at low levels.
We converted and the chlorinated baffling, and wound
up with the chlorate modifier, which
was more of a concern in California in
the trichloroethylene. So we had to take steps to control the
migration of the VC that we produce.
>> Biological treatment, is another
technology that we can use, you can do that array Bickley or anaerobically.
-- aerobically or anaerobically. In situ it is
more difficult to control, a lot of it is used
with composting, I've got an example of a composter down there in the
lower right, that you could the.
This is actually a Windows system, you
have rotating biological contact, there are a variety of
ways to try to use biological treatment.
The best known is activated sludge.
>> And the emphasis of time I will move along, so if we go to apply
any one of these remediation technologies, first of all we have to have a pretty
good site assessment, you're going to have to have the contaminated
of concern, some soil characteristics, a lot of the
geology because of you have pockets of rock and pockets of clay, that
is very important, where your groundwater is etc. You have to consider
your costs, and of course most of the time we want
to have the most cost-effective technology that is still beneficial
to the public the best. You have to look at your regulations, there
are many regulations that come into play, as a matter fact
many times the regulations that you
must meet, then you have the public, and of course the public
comes up with a knot in my backyard since them, a lot of times you go
into remediate, and you have the public hearings
to have what you're going to do approved or remedial action boards
involved, so you need to coordinate upfront, if possible. It is terrible
to do it on the back end. You need to come up and work with
your regular -- your local regulators, to get preliminary and primary
remediation goals. So you know what your
targets are, which are very hard to establish and you have to work
closely with the regulators. And then if you're going to have a enclosure,
you need to establish what you have.
>> In summary, we have many technologies and we have some
good success stories, I showed you Rocky Mountain Arsenal, here's another
mining site, and it was extremely contaminated, due
to the fact that the mining operations and we
basically, the site was destroyed due to acid down drainage, that
impacted the stream, and then you can see it after they
had closure. And some of the remediation efforts. Here is
another site, I'm a little more familiar with this one, this is
the climax mine site
located if you've ever been skiing up near Breckenridge it's up in
Leadville, is on the continental divide, and they
mind -- they worked this mind, mostly active
in World War II, they recently reactivated the mind
-- the mine, you have the
Atlantic and Pacific side, this is
actually showing the drainage and how
it impacted the Pacific drainage area, and this is after they remediated
it. And so they were able to establish vegetation on the site and it is
nicely graded now. That concludes really
an overview of sub- technologies, hopefully you are not to board,
I guess if there are questions I would be glad to address those.
>> I will turn this back over to the moderator. All right thank you
so very much. I just want to remind
the audience, if you have questions or comments for
our speaker, you can submit them electronically using the Q&A window,
in the bottom right corner of your screen at
any time. I know a few of you have sent us some questions in, so we
will certainly pause right now to read through those questions. And
have our speaker address them life. I wanted to check in
with Cindy, and make sure that it is okay that we start with those
online questions? Speak -- >>. Yes
please do.
Professor Mark Bricka, the first question asks if there are differences
between led remuneration for inorganic lead, such as those that you might
see at a small arms range and the
organic led from an old gasoline release.
>> That organic lead, that you are referring to, actually
is added a bromine led complex. Lead
in itself is organic or not,
it depends. The species can change back and forth depending on
the redox potential to the soil.
What kind of pH that you have, what kind of Wigley's
down there will convert it.
Basically if you can get the lead and form a +2. a lot of times and
in these technologies that I talked about will target that let's. --
that led. That organic lead can be easily oxidized to
an inorganic form typically. I hope that addresses your question?
>> Thank you so much. Our next question
gets into remediation, I re--- it is a
comment, the remediation seems to have lost
favor except for providing cover to grow at elevated concentrations.
It is not actually being used for removing heavy metals from the soils.
Can you talk about that concept?
>> Since I moved from the Army to academia, I've become a little
less directly involved with some of the cleanup activities. But I
do know, that Phyto remediation for lead was being
used at many smoldering sites, they were putting
Brassica Indian mustard out there, and hyper
communicated that -- accumulated that and harvested. Some of that
I think is still occurring, due to the fact that you still must
do something with the plans after you
accumulate that, that is the drawback to Phyto remediation, it
makes great groundcover, but when I am talking about Phyto
remediation I'm talking about the contaminant moving into the plant,
not just keeping the plant from -- keeping soil erosion
from occurring. So I agree and disagree.
>> Thank you. The next question,
is probably hard to answer, but I will put
it out there. Out they want to know if one of those technologies is
considered more cost-effective for heavy metals? If so which one? Digging
holes is the most cost-effective, in many
cases you are still having to put the residual into
a landfill. If you do not treat it, and you put it in the landfill
that is always more cost-effective.
But, you really need to look at a lifecycle analysis. To figure
out the cost. In many cases, we have to haul it a
number of miles, you start looking at your
fuel use, you start looking at the environmental impact, due to large
trucks on the road, the impact on the road, the fact that you will
have to repave and the money associated with that,
if you do not look at all the costs involved with the technology sometimes
it appears cheaper. I will just answer
your question by saying it depends.
>> Got its call right. And then you gave an example of a site where
technology was brought in to address heavy metals but it wound
up adding in a layer of complexity because they had other contaminants
of concern on site. This participant is hitting him with that idea, do
you often see these technologies combined
with others to address a range of contaminant concern? If so is one
of these technologies sort of better art to be able to deal with
things more contaminants, something perhaps
more flexible on the list that you provided
to deal with a range of contaminants concerns? I can actually
say when I began in the remediation area, organics
were the target of concern typically.
A lot of times you would apply
a technology that would treat the organics and sometimes it would
have an effect on the metals, a lot of times the metals were left
in place, if you removed the
organic contaminants. You had an individual technology, later we
actually proposed what we call combined technologies, it seems
to take favor, so now the fact that it is not really favorable
to leave metals in place, and we have a lot more information
on those, you can put several technologies there
for example of physical separation to take out particulates, and then
turn around with some type of extraction technology, washing technology
to treat the fines.
The particles. There again, it depends on your particular site
and the conditions and how much money do you have etc.
>> All right, I think in the interest
of time we will move on to our next presenter. I did want to thank you
very much for joining us today.
If participants have additional questions or perhaps you are in
the middle of typing something up or
Professor Mark Bricka, you can continue to send us questions and if we have
time left over the end we might circle back. So if you can stand
align with us Professor we would appreciate
it and we might come back to the end of the
session today.
>> With that, I will call up the next
presentation, and get ready to turn things over to her second speaker,
who is Mike Truex who is joining us
from Pacific Northwest national laboratory where he is a senior
project manager there. He is been there
since 1992 doing remediation research in field applications. If you are
on the line please begin your presentation.
>> Thank you, I am happy to present today, but
I would like to talk about, is the process of selection and
limitation for Radionuclides in soil and groundwater.
I want to focus on the type of factors that I think are important, and
primarily thinking about the site where you may need to
consider contamination that has sustained the ground and had we
managed that. That is a concern at some sites, because
certain techniques are hard for instruction. How to be go throughout
that process? -- how do we go through
that selection.
>> My goal is to have the discussion be more
generally applicable, but those are the types of examples that I
will use. In doing this and presenting this material
I would like to build from the bottom and then move into this, I would
like to talk about Radionuclides characteristics and how those are
related to remediation and remedy selection process. And
also, think about and it states, and attenuation and how
that relates. I will do a bit of introduction on those sorts of
elements, and then get into the example of how we think about all
of those things together in terms of selection
and implementation.
>> Starting with Radionuclides characteristics, they have
different types of properties, those are either our friend or our faux.
When you think about half-life, not
how fast something decays to something innocuous, shorter is better, you
might have that is an impact to the about, such as things such as
[Indiscernible] with a relatively short half-life will be a different
dynamic Vince things such as uranium, that has
long half-life's. You have to understand the factor for those
characteristics. Mobility is another characteristic, that
is important, and that is what you classically think of as sorption
and how it relates to how the contaminant moves in the environment.
And then of course, there are different factors
with that's.
Low mobility might be generally thought of as
good, because the contaminants might not move, you have them sequestered
in an area that you can get out.
You can use direct extraction technologies. If you
have medium or high mobility, that can be good or bad, it is good in
one sense, if it has a lower mobility, because maybe the transport
is attenuated, and that might not migrate as far you
can use it attenuation approach as part of
your mediation. But if you're trying to extract that, using something
like concrete than that is fighting that. Any
type of interaction with the sediment, is something that you should really
consider in terms of secretary -- secondary sources. And
may have moved somewhat during that disposal period, and now we might
be worried about the secondary source.
The contaminants that are accumulated on the sediments because of lower
mobility, but not low enough that they can still reach out and
create continuing problems.
>> These are characteristics that we need to gather about
the contaminants. That we will be concerned about for a
given site. And then of course the other aspect, is
biogeochemical reactions. They are important with the chemistry of
these materials, sometimes I can be
helpful, uranium and strontium actually interacts really well with phosphate
materials, and create low solubility.
Precipitates they also uranium also interacts with silicates,
with the same effect that can be enough of an advantage, if we
think about technology. But others are a mixed bag, uranium and iodine,
and chromium, interact with carbonates, so they will form or dissipates
which are moderately soluble. So that I can
be good in some ways, where that may be and
attenuation mechanism, and small movement of the contaminants, but
it may also lead to creation of the secondary sources. Transformation,
in terms of [Indiscernible] between's chemical
species can be helpful or not, and so iodine for example, is
actually President in a couple of different species in the sub service,
I can be present as [Indiscernible]
and redox sort of situations, where you have
a reaction where changes in those species but none of the species
are completely sequestered or tightly held with the sediment, so
that reaction is only moderate of
helpful if it leads to a subsequent step that may be helpful to the
remediation. Similarly with uranium and TCM, oxidize species are
typically mobile, the redo species are typically not, but
redox may or may not be something you can control of the site. So
you have to think about that. All of these characteristics have to
be understood, in terms of whether or not they will be a rendering
02 what you are trying to do a your particular site.
>> Another part there would like to emphasize, it
is not just the contaminants chemistry that is important, it is the context,
the other chemical settings. The example I use for that, is actually
the disposal chemistry. Depending on the type of site
out there, the contaminants may not of been disposed as a pure chemical
it will be disposed with other components.
At the Hanford site we had disposal chemistry that was very acidic,
and some is very alkaline. For uranium that makes a big difference, at
the left-hand side of the slide, if you have
acidic disposal, that acid will be neutralized when his the sediments,
during that neutralization what happens is you actually dissolve
the sediments that is how neutralization occurs, and you will
do so carbonates, phosphates, and silicates, as the solution now becomes
more buffered toward the neutral pH you'll have precipitation, and
some of that I can pull out some of the uranium phosphates. In
that process the chemistry of the disposal actually impacted the distribution
of my contaminants, and his subsequent further movement through the soil.
That you was also thrown a lot of -- now, you've also thrown a lot
of solutions, that may affect the absorption, you has positive
and negative effects, for an alkaline
situation the same thing happens, you have neutralization, in that
case primarily from silicates dissolving, you have uranium silicates that
might form. These sort of things are part of the contextual
information that you have to think about when you think about
Radionuclides characteristics and how they affect what you're trying
to do.
>> That all really comes together when you develop your conceptual
site model. That is where you bring all of these pieces
of information together, here's an example of what
a conceptual model components that we
thought of for iodine that was disposed of at the site, you see
that we had to think about the inputs, that waste disposal characteristics
we had to think about what happened in the zone, as it moved through
the soil what kind of hydraulic factors or reactive feces might
be important, as we look at the
hydraulics and water factors we need to look at their
all components with the context of what might be important. For
the remediation process. The one danger and thinking about all
of these pieces you have to synthesize that. Which of
these processes are controlling our most important for what we are
trying to do. And before that I think you need to
take a step back, and think about the
broader picture. We talked about what type of site data you might
have in terms of discharges, and source terms of developing the conceptual
site model, that was a static model that I showed you on
the previous slide. What we found, you really need to think
about the system as dynamic. The whole system
and how that contamination is moving, and therefore what you need to do
about that. For that, we find that actually applying some of the approaches
that are out in the really good natural attenuation guidance
that is out there, those guidance approaches have you
focus on what is affecting the movement
of the contaminants in the ground.
That is a part of whether or not they will move to apart my point
of continuing -- concern or attenuated. So
you can define that and define the model and quantify what that transfer
looks like and how does it relate to whether or not these contaminants
will reach points of exposure or how they might attenuate
over time and achieve benefit use goals. That helps you define
what is the risk and therefore what is the and states,
-- end states, how much stays in the
ground and how much needs to come out of the ground to reach my goal.
That determines the remediation strategy and the
cornerstone of that, is determining what is happening already. That
is your natural attenuation components, that may be enough, a
full remedy, it may have very little impact. You may need to think
about what kind of active remedies will be remediated,
or you might be in the middle ground, well
-- where attenuation is helping in some ways and help you focus
where you need to apply enhancements that will
be able to allow you to meet your overall goals. The main point
of this first part of the presentation is to say
think about those characteristics, but think about them in the context
of the chemistry and biology of your system, and then think about
them in the context of what it means in terms of the way things are moving
and how can we wrap that into of what I want the end sites
to be.
>> That is a starting piece that we can now think about when we look
at the process of remedy selection. I will go through
some examples here, and try to talk to through things that I think are
important. Again, the department site has a case study and
I will focus on this idea of attenuation and transport processes this is
the way that we pull this all together, and think about what the system
looks like now and how we might need to change its to meet
our goals. The other important thing that I want you to think about is
the idea that remedy technology decisions really relate to a number
of different things, one are the Radionuclides
characteristics, the other is the target problem, so that again is
the context and how things are moving, and then we have to
layer onto that the different types of functionality that a specific
type of remedy might have.
It might affect the hydraulics, the chemistry, how does it change
the system to meet our goals, and then of course that all has to be
thought about in the context of a remediation objective. I
will walk through the components and hopefully give
you a way to synthesize these together, and a way that we've been trying
to think about this at the Hanford site.
>> To give you some background, some of the things that we have
to think about at Hanford, this is a slide that shows
the type of things that happened at Hanford, fuel elements
were manufactured, so there was a lot of
uranium processing, that occurred
in our 300 area cost of the character of the waste is related to uranium
and also the chemistries that
were used during the manufacturing process.
Up along the river, where the nuclear reactors were located, fuel elements
were created -- your radiated, and
another character of contaminants and chemistry. And that an essential
part of the site, the 200 area, the
central plateau, they did chemical separations of this fuel elements
and that is where they extracted the plutonium,
there we had a whole different nature of
chemical processes being used. A lot of different chemistries, in
terms of what was included in discharges to the environment, and also a lot
of different types of radio nuclear lights. Now were trying to --
Radionuclides. Never trying to extract, there are a lot of these
included. That gave us the context that we have to think about that
when we are in the environment of restoration.
>> The other part about Hanford to
think about, this is a picture from the groundwater plumes, that emanate
from the central plateau, or central processing sites.
You can see the scale here, the scale length is about five kilometers,
so these are very large plumes, the reason we have large plumes
there was a lot of water used during operations that went with
these wastes, there is a big driving force, this pushed the contaminants
through Ara vadose zone and created large plumes.
That is part of the environmental legacy of what was pushed into the
groundwater during operation. But not all of
the contamination got to the groundwater, there is
quite an inventory, this is an example of some of
the technology, TC 99. and uranium inventory that we have a different
areas within our central processing zone. Because some of
these materials are still in the vadose zone we have to think
about the future of the zone and contamination
at its potential to continue to contaminate the groundwater. These
are a couple of things that we will talk about in the next portion of
the slides.
>> As a context to the about, out of that central
processing area, we discharged waste of the service, some of those ways
were put into tanks, and there have been
releases that may be did not reach groundwater,
like I talked about there are some releases that push the contamination
all the way to the groundwater but we stuff to think about both, the
residual, and the current groundwater plumes. When we think about the
conception models. Here is a recasting of all of these factors, that we
have to think about, this is a laundry list,
and that is not the way we want to go about our remedy selection
and rotation process, we need to be focused and think about what
her controlling those the movements of contaminants and had we
mitigate that. Instead of thinking about the laundry list, and all
of the components that might be important,
we're going to think about the vadose zone in terms
of if we have a waste discharge, we know that now we have a source
or an amount of contamination in the vadose zone,
we know that it is movement through the vadose zone it is
attenuated, but we want to know is how does that process occur,
we are interested in the flux to groundwater and how it is relating
to the resulting plume. If you think about it as a
transport process and actual attenuation, if you did not have a vadose
zone and you just had a source of the
groundwater you think about the source, the source flux, and the
plume that is created and how it might be attenuated. For us at Hanford
where we had a discharge of the surface we had the first two pieces
that are linked together and happening in the vadose zone, and that
we have a groundwater attenuation capacity. That we have to be concerned
about. So that is a first step, thinking about
what is the context of my problem and how will I think about what
the controlling factors are, with Hanford we have to think about somebody's
controlling factors in the vadose zone.
>> What we need to know? A primary factor for us
is figuring out how we quantify what
the flux from the vadose zone contaminants is to the groundwater
that will tell us is the source a problem or not a problem. Is
enough continuation happening in the zone that we will not create
a plume zone? We want to know where contamination might be
and therefore that might help us focus were mitigation efforts would
be of most value.
In the groundwater we are thinking about this idea of what are the
current plume dynamics, and how that might occur until this dynamics
might change in the future. And what might those secondary sources
be cut do we have some compounds that might've got into
the groundwater, and are now associated with sediments that provide secondary
sources that we have to work on for cleanup. If we do
something active, we started this whole thing talking about and thinking
about the continuation processes, if those were
not enough, and we applied something like an active remedy, then the
question is how much do we have to do to diminish that contamination
could get back until we might then be able to allow attenuation
to be our final part of our end state in our final zone
and go. Think about the process right
a friend is important, it helps focus how we need to think
through what is important for us to understand about
the site. And then will I talk about vadose zone and
groundwater independently, of course it is a couple system like we talked
about in that last slide, we need to assess is continuing and long-term
sources it is not just a current plume, it will be the whole couple
system. Again think about building that conceptual model, building
that site understanding and thinking
about staying focused on what is important. Part of that will be
thinking about coupled systems.
>> The reason for that is, we have these enormous
plumes, we do have to do some work to try to mitigate those, and
think about what is appropriate to diminish those, but we had these
remaining sources. So we have quite large amounts
of mass, still remaining in the vadose zone, and we have to think
about the whole system.
>> So now let's talk about well, what kind of information
to be gathered? Had we think about this? What are
the processes that are important, will have to think about hydraulic
processes, as water moves, there is
dilution, processes in the vadose zone in terms of how
water moves and mixing, and those will all be important, we need to
know something about that, we talked about adsorption, and how does that
relate with contaminants interacting with
the sediments. And transformation, was sort of reactions might change
the species or the type of chemical species that you
have for a Radionuclides, and how does that relate to how it might
be sequestered in a different type of precipitate that might have a
different mobility than the previous four. These are all things
that we will have to consider, the reason that they are important,
we need to understand the source flux, and how that relates to
what might be created in terms of a plume, we are also concerned about
the inventory, you might think that you know the
inventory because that is what you jump to the ground, that is true,
we kind of know what we dumped in the ground to will some extents.
But we are interested in the inventory of contaminants that will still
be mobile and relate to groundwater plumes. I was I will
talk about later, there are some of the chemical reactions that
have happened at disposal, that might've sequestered the contaminants
and in mobile forms, so we need to understand the inventory. Spatial
distribution is important, it
will be related to where we will target our remedy efforts, and ultimately
plume dynamics will control how we think about the groundwater system.
It is sort of in this case,
what I'm talking about in terms of the ultimate receptor, and what
we need to think about in terms of restoration, there are goals
that we have to think about for the vadose zone with our contact
in Hanford we are in particular thinking about the vadose zone
is a key concern relative to its source to groundwater. How do
we protect that groundwater. Here we emphasize
that a lot, there may be other drivers at other sites, but for my presentation
that is the context that I will be talking about.
>> Now let's talk about the vadose zone, I want to give you an example,
we started characterizing the vadose
zone at Hanford, right in front we saw and thought
about what do we need to include in our sampling
and analysis? The sampling and analysis plan tells us what we target for
this characteristic effort to connect we need to think
about what are the important hydrologic units in the vadose
zone, factors that might be important for controlling how contaminants
move. What of the representative contaminant discharges, joy have
to think about acidic conditions, alkali
conditions, at Hanford we have a number of different Darst
charges, -- different discharges, how do I think about that chemistry
and had my characterize that. What do I know about chromatic way
sites, -- automatic waste sites, high concentrations and high discharge
of volumes, would like to think about
in terms of the characteristics. That helps us get
the context for targeting but we do in our sample analysis. Then
we did was we look to the series of different types of analyses,
the we did. To focus ourselves and what we need
to know in order to best understand what controls movement
of contaminants and how best they my move, and how that relates to
the flux in to the groundwater. Part
of that is thinking about the contaminants of concern in their concentration,
and the chemistry that we now see in the groundwater, or in the vadose
zone that might relate to how it moves,
we use techniques such as sequential extraction, another indicator diagnostics
because it is not just about the total concentration, we want to
know how the contaminants are distributed between office phases or phases
that are different levels of association with the sediment.
I will talk about first we applied water to the sediment and we see
what kind of contaminant concentration comes out when you extract the water,
then we will apply different levels of more harsh extraction, and that
gives us information about how contaminants are distributed between the aqueous
phases and more and less and less mobile
sediment phases.
And that gives us information about contaminant distribution but we
also want to know how does it behave?
That is where we can talk about quantitative analysis,
leaching tests, where we might put soil into a column and flow water
through it and see what leeches out and quantify that and get the
kinetics of that process, or we might do absorption test, or batch
KD studies, where we contacted sediments with contaminants to see what is
the partitioning behavior of those, now we are looking at
quantify, their characteristics that are important for defining
transport. That we link to look at
hydraulic properties that will be a part of setting up.
>> Let me give you some examples, we talked about this in general
terms, here are some examples of the type of data that we get from
these experiments. Here are some sequential extraction data, this
is for a number of different samples that we went through from the vadose
zone, this is a different kind of extractions that we
use groundwater, what comes awful repo groundwater in contact with
the sediments? After we did that now we are going to apply an ion
exchange solution, then we will apply different
pH acid solution sequentially, that will offer the carbonates, and
iron oxides, and we will apply even harsher assets such as silicate
acid and nitric acid, but we see these of
the character of uranium that comes out if extraction solutions. What
you might notice from this, is that only a small
fraction of the total uranium came out in just the water. This is a
really mobile phase uranium, it is only present as a small fraction
of the total, then you see some others in this
particular sample that is associated with carbonates. What you see is
of this total uranium that is present, in the soil, a lot of it
is sequestered in pretty immobile forms. Would
really check, only a small amount actually comes out of the leaching.
Primarily those were associated with the aqueous phases, or the
carbonate phase. It is important to know, that changes our inventory
of uranium that is mobile, and it also gives information
about what do we need to be concerned about for
leaching of the groundwater. The same thing occurs with iodine, you
might think of iodine as iodide or I a date and it reacts
with carbon, is the mobile phase iodine, this is the
phase associated with carbonates, and iron oxide, you see very low
levels of leaching, yet a bigger inventory.
This is important to understand in terms of looking at the source
in the vadose zone.
This is an example for uranium and iodine, we saw the continuation
factors that are very important to it, there his [Indiscernible]
which is present as [Indiscernible].
All of this came out when we contacted it with water with the ion exchange
solution. There is not much attenuation of TC
99 occurring, so that gives us a different targets
when we think about remediation of TC 99 versus uranium
or iodine in the vadose zone. That is why we do these experiments to
give us that information to help us focus our remediation.
Here is another example for uranium that just shows how
this profile of sequestration of uranium might change
with depth.
Here is what you see a fraction of these different components. You
see the fraction of the mobile components actually are much higher lower down
in the vadose zone, then you might expect because it has moved
deeper and that we have the less mobile phases and a lot of this
yellow material up top, look at the numbers of total uranium's,
these are fractions, the total uranium in these first two samples are 690.
387 micrograms, then we only have 10 or less than one
lower in our profile the reason that
occurred, appear, because we also disposed of alkaline
solutions, at this particular site, a lot of that uranium has been
changed into uranium silicate so it is no longer is mobile so
much longer -- much less able to travel down the vadose zone. We
also see other folks looked at this in terms
of characterizing nonmobile and mobile phases, and again you can
see it is the inventory and the nonmobile
versus the mobile that help you decide on your targets. What we
have to do in terms of remediation, and how much has attenuation helps.
One other example, that we looked at, in
this case, acromion, although boast I a date in uranium
interact with [Indiscernible] we had an assist to
-- acidic discharge, further down the profile, that carbonate will
re-precipitate and it does incorporate chromium in this
case in that carbonates. This is an example
of a Hadfield filled sediments, at the groundwater, we have this
material that was generated during disposal, and it is actually
a secondary source for us now, this material is not completely immobile,
it is not completely insoluble it will dissolve slowly over time and
that is what we have to know manage with the fact that we have the
secondary source. That is something that we have to account for, when
we think about the remediation for this
particular site.
>> Those are some components of the chemistry that we have to think
about, in terms of Radionuclides or
metals, and how they might relate to our decisions, we have to know
where they are, in some cases, they might be only a
small portion of the vadose zone because only a small amount of
liquid was discharged, and there has not
been much movement since then. In other cases you might have different
zones of your vadose zone where you have different concentrations
or different chemical reactions happening in the Green zone versus
the yellow zone, but we still need to know this overall distribution
of where things are located. So that we can think about the chemistry
information along without. Typically, you drill the holes and get the
samples is how you do the chemistry, during the drilling you might have
geophysical logging, to look at the spectral Camelot, the neutron
moisture law, we think it we have been applying now, it's important
to think about these in three dimensions, one way that
we do at the Hanford site is to look at
the topography, it essentially looks a where
the higher connectivity material is, a lot of time waste materials
have higher conductivity than in the surrounding native material.
Discharge is is the ionic solutions that came with that waste, they
are higher conductivity. For us nitrate is a big signal for us,
so here you see, have you where we have
the different features, the stakes, entrances,
and fields, and then down below them here is actually images, of
the plumes. I can actually see where the
water moves in the nitrate moves, and I know that that is the path
that my discharge went on his way to groundwater. That
is nitrate and very mobile can situate the light of a signal. That
does not mean that uranium is all around that path,
uranium absorbs to the sediments, or reacts to
be slows, but now I know the outer hole of
the path those contaminants might be located, that helps us when we
decide where to drill, and also helps us think about the magnitude
of the distribution of contaminants within the vadose
zone. Versus how they might behave in the future in terms of the groundwater
source. So that is another component that we added to how we
think about vadose zone sources. I will walk you through
those chemicals, a larger scale factor that we think about, in
terms of building the case for how we select a remedy of the vadose
zone. The groundwater we have some similar things, that we have to
think about. Here are the same types of things that we did with the uranium
in the groundwater, we grab sediment samples, we did the sequential extraction
procedure, and here again even in the groundwater there
was still reactions that went on, the sequestered some of this uranium
in less mobile forms. But there are
still leachability. So now we are in the groundwater, the movement
of water now, is much greater past these uranium materials
that are in the sediments, they will leech off, here's an example
of how much leeches, this is an example
where we have a secondary source we have to think of, it is good
that they are
interacting, with the sediment, but in this case it is giving us
a secondary source, so that attenuation is something that we have to think
about in terms of how does this relate to for example how do
we treat this unit or how it might relate to a continuing source, that
then drives how the plume will diminish.
>> The same type of characteristic is now being applied in different
hydrological settings, it is important to how we are now going to go and
select the mediation that is most appropriate. Will give you an example
about. And the 300 area, this is where we
did they uranium fuel manufacturing, they discharge waste into trenches
and ponds, and there are uranium contamination
that went out with that. They dug up a lot of
those old discharge areas, but there is still an area where they could
not dig underneath those facilities where
there was uranium in that vadose zone. At
this particular site, we are fairly close to the river, and the river
seasonally goes up and down. So that changes the water
table and so seasonally, the of water that moves up
and touches this uranium contamination that is still in the
vadose zone. That can flushed it out, into the groundwater and be
a continuing source for our plume.
What we would really like is this uranium to be less mobile,
every time the water came up it would not grab so much uranium flushed
out into the water table. That might be
a strategy for remediation is to make this uranium
less mobile. To decrease the source.
That indeed was the strategy without about. We went back to the chemistry
that my do that for us. Reacting uranium with phosphate
creates low solubility conditions. It
actually conforms uranium phosphate low solubility
minerals, here's an example of where we took some treated sediment,
with phosphates, and put it into a soil column, and ran water through
the soil column both were treated, sediment and
untreated sediment.
A couple of things to notice about this, what is it does not make the
leaching zero, that is very hard to do, you see that the leaching
rate of this is basically a low and
steady rate. What that means, every time the water would come up and
touch the sediments, only a very small part would come out
with uranium. Through for a typical traces of uranium low. With the
untreated sediment you eventually get to the state, the slow peers
the same of the slow., But the bad actor Doris is this
near-term uranium that is still in mobile forms, and that is what
the phosphate treatment did for us, I took the material that is
so mobile and he created less mobile forms so now when the water
comes up you cannot pull this material out quickly. And
uranium concentrations a low.
>> This is where we are thinking about the context about where the
radium is how it is contacted with water, what chemistry might make
sense to help us achieve our goals of keeping the
uranium concentration and groundwater below.
>> I walked through those sorts of examples, I will
move into some things that we might do is start thinking about evaluating
different technologies, a lot of times we think about doing treat
ability test, or other types of assessments and think about the
characteristics now, of the remedy functionality, but we always have
to think about in the context of these other factors. We will talk
about a couple of quick examples you might think about soil
flushing, or service barriers and desiccation, or uranium sequestration.
I will give those examples and hopefully they will be constructive
of the type of things to think about when we think about technology evaluation.
>> Going back to our diagram where we had before, when
you think about soil flushing, this might be an idea where we know we
have contributed distributed during the vadose zone, we
might say if we can flushed this conference
I contaminants down to the groundwater where we can capture it, and get
it out there, of the system, that might be one way to
treat this. What we have to think about goes back to what we did in
terms of characterizing the site, if we characterize the site, and
we know that some reactions have occurred,
the sequestered uranium because of the disposal chemistry or interaction
with sediment, or because it might have hydrological
layers the slow uranium movement, those are things that are still
owing to impact us if we try to flush that contaminant out.
With that situation, then flushing might not really be effective. It
will be fighting all of those things that actually help sequester the
uranium in the vadose zone. Razz we might have another
site where maybe we did not have so many those interactions, or maybe
we have a contaminate the doesn't have those interactions, and in
those cases we would be more successful in actually moving contaminants
here into the groundwater and capturing it. Here are some of the factors
that build off that information collected earlier, inform us --
inform us as to whether this is a reasonable technology to pursue.
So the other thing that we might think of, if we had a condition
where uranium of the contaminants were sequestered
to some extent in the vadose zone but not enough for us, we might
have a think about putting a serviceberry on it, with
the idea that that lowers the amount of water that flows through the
system that will lower the flux of contaminants into the groundwater.
That would be a remediation technique, how would that work for
us? Here are some examples of how we thought about that, here's an
example site where these represent
technetium 99 underneath three different cribs,
the different discharges led to different distances that it
has moved. And if we left the TC 99 alone, this is what would
happen. If you let a recharge, water migrates through
the vadose zone, and pushes the vadose zone
-- dc 99 through, we have about 144 curies
the moved into the groundwater, you see that here in the
flux rate, you see the flux over the next couple of hundred years
of why this happened is there are still water moving to the system,
there is water that is training and going through the
system, this is part of the water that used to
be discharge, no here's the water wherever time it is a
natural recharge rate. We put a cover on that's, the effect of that
is to now we are going to drop out recharge very low. Now that
will be less water moving to the system, and you see that drops the
total amount of discharge to the groundwater, and keeps his flux
rate low, but you notice it could not stop all of it. The reason is,
there is still some water that was down below in
the system, this still is going to drain out before the effectiveness
of the service barrier takes effect. If we can remove that
water by desiccation, which is basically blowing in dry air, about bring
that water creating dry conditions now I can really limit the
amount I contaminants moves into the groundwater. The reason is we
have much more rapidly dropped off this water, to reach my low
recharge conditions. So that is the case where we looked at this
over hydraulic system and how do we affect this to reach my goal
which is to slow down the rate of movements at this material so that
it never gets above groundwater concentration concern. And we had
to think about all of those attenuation mechanisms and transfer mechanisms,
and the remedy functionality in terms of what this be something
that my work for us.
>> Here's another example, this is similar, there are a lot of different
ways that we buy sequester uranium, for example, phosphate might be
one of those take weeks that I talked but earlier. In the vadose zone,
it is very difficult to move phosphate because it is a liquid form. Will
one thing that we looked at was if I so want to sequester that uranium
maybe I can use a gas, we found this we can move ammonia gas,
if participants into the water, where it becomes
ammonium, and that process of pronated, becomes a high pH
condition. And that dissolves some of the sediment. What is dissolves
this primaries legates, which come into the solution, and then as that
pH decreases, because of buffering and because
you have IE9 in the solution, now we will create precipitates which
include things such as uranium silicate which are
not as mobile as the type of uranium that we had previously. So now when
I compare the leaching, and the soil column,
I put the soil of MacCallum run water through it untreated I
get is continual release over a couple of
hundred volume, when I treated it with ammonia,
I did not make a zero, but now look at how much water out curve is,
but we have to think about is, did that
chemical change will reduce the leaching rate will
help Michael in terms of reducing the flux to grandmother
-- grounds water, and that's retake
a chemical reaction to this, and we think about the
larger terms in terms of transport and impact on
the groundwater.
>> Those are a couple of ways we might think
of, evaluating how technology might work for us, the types of things
that we think about, now we will look at the types
of targets and how we're going to move to implementation. We have
to think about where are we going to play this, I talked a little
bit about this, where the chemic history might've happened, --
chemistry might've happened, what form we
are in, how much do we have to reduce the flux to meet your
goal, if were going to do something where we leave contaminants in the
ground. That is comparison to if I need to do
some extraction. In terms of in the groundwater we might think about
similar sorts of things we might think about how do
we diminish the current plume how much do we diminish it and what
is the impact of my secondary or continuing sources in the whole
process? And in my long-term solution how does that
relate for example, to transitioning to M&A, this whole couple system
that gets us to think about how do we
consider current plumes for long-term sources would we go out and were
going to implement the remedies having gone
through characteristic and the selection processes we talked about I think
the thing to talk about that is important that we are using in
terms of selecting and implementing remedies is in
many cases while it might be nice to think about a plume, where
you say this is the plume and this is what I know about it and here's
my remedy, get a go out and I'm going to be done. Sometimes you
have a simple situation where that might have been, but
many times if there is uncertainty and how different remedies
will work then you may need to think about multiple components to a remedy
or maybe staging it in time and that is what we talk
about as an adaptive site strategy. That came out with
the national research Council looked at the status of rad water contamination
and remediation and says there is a lot of sites
out here that have tried some remediation and they have not been fully successful
because the system has some complexities or challenges and they might need
to think about doing more of an adaptive reproach
-- approach where the implemented technology the reaches a goal enough
they reach that goal they think about what would be the next step
where I could go one step closer to my
ultimate goal. The national research Council talked about this and there's
recently an ICRC or interstates technology regulatory counsel with
a group of state regulatory's that created
the document of remediation management of complex
sites that talks about understanding your site, thinking about what is
going to be important to doing
remediation, and also recognizing that they might
have to take steps to do that remediation as opposed to just pick a remedy
and apply it and boom you are done.
That is not always happen. This is a nice document that talks about
these processes, it is available now. The other aspect
that is been coming out recently is thinking about the idea of we
may need to go out and apply active remediation.
>> For example to treat Adam -- or diminish
a plume. How much do I have to diminish that plume? Had I think about
criteria for how I might stop the active remediation or maybe transition
from pump entry to other type of remedy that might be more appropriate
once the plume has collapsed to a secondary source.
Now you can attack a smaller area with the secondary source with another
technology. There are also some guidance out
there now, that we have written relative to developing exit strategies,
and thinking about that transition point. The last thing that I would
like to talk about, talking about remedy
selecting and implementation, and chemistry, and behavior of contaminants
and how we might go about this project and process. One big aspect
of this, one big element that relates
to this whole process, is monitoring.
Monitoring is something that gives you information
during characterization, territories and
-- characterization should not just be thought about taking the
samples you need to monitor the groundwater and think about how
are things changing over time. And you need to target that
to have a certain objective, whatever he trying to find out, had a monitor
that it had is that feed out like into understanding
the sites. Monitoring is very important to integrate with the remedy, we
need to think about the form metrics, and how we provide the
feedback on the course of remediation.
Especially, if are going to be thinking about
adaptive strategies, the adaptive strategies having to take a step
and see how works, and then at that will inform into my
next step the monitoring is very important to that, and transitioning
from maybe an active to a long-term strategy, you need to think about
monitoring in all of those purposes.
>> I can tell all about monitoring in this presentation but I cannot
do the presentation with emphasizing that that is such
an important portion of this process.
>> I will give you another example, this
is [Indiscernible] at Hanford, back when the discharges
were occurring there was a lot of water that got discharge, you can
see the outline of SR 90. You note that this plume
is a lot higher than what the current water table is because
a lot of water when in here, the water table was hired during discharge.
There was a big driving force that moved this at this
time. Now, with this much lower water table, there is not much driving
force for that SR 90 and it begins to decay
over time. Because it moves slowly and decays fast relative to
that movement most of this plume here is going to decay before reaches
the river. But not all of it.
So that is why we installed an
appetite barrier, it helps control the flux to the river. That is part
of the remediation strategy were something,
the permeable reactive barrier here and the continuation of the
program and the way we monitoring those areas are different.
This process will change over a fairly long period
of time so we can look at snapshots in the plume over time, maybe a
fairly long intervals because this is not really changing
very rapidly. Whereas here the river, we may need to consider performance
metrics that are much more closely tied to that dynamics of the
water movements and the dynamics of this treatment process. We might
have to apply more intense monitoring
care. The whole idea is that we need to link that monitoring, to
the type of remedy approach and provide feedback. On the performance
of the barrier in this case, is a performing as we
wanted to, and back here we are looking at the performance of longer-term
natural attenuation processes. Again, it is the whole idea that we couple
that monitoring with the overall remedy process. Like I said, it
is not a monitoring presentation but I can't do this presentation
without mentioning monitoring.
>> In conclusion, I want to go over
some of the areas that I tried to emphasize, the first area was what
we think about classic characterizations I'm with
concentrations and extent, how is that contaminant moving, and how
is it behaving, and the environment, and really some
nice information that we can borrow from the natural attenuation guidance
documents. Think about those
and the methods in terms of characterizing attenuation
and transported how that relates to the remedy selection process.
That remedy selection process is decisions, the intersection of
a bunch of different elements that we proceeded to
think about, characteristics, target problem, functionality and objectives.
I judge provide examples -- i tried to provide
examples of how to integrate those samples into deciding how
to proceed. And then of course the last part, is when we go to implement,
again emphasizing the idea that with many of
these sites, where it is not going to be something that we can dig
up and haul away and be done with, we have other challenges maybe
a larger plume or different challenges with applying
an extraction technology we may have to think about adaptive site
management, where we take a step white approach, and that is important
for the new area that is been emphasize in I give you
references to document that. Exit strategies are part of that,
because that thinks about the idea of we may need to do something active
in the near-term but in the
long-term maybe I'm transitioning to there's
some different type of remedies, or maybe natural attenuation. That
is an important continuation when you think about a
friend because you want to plan for what you are doing instead of
just reacting to a system failing.
You want to think about how that used to -- should of been thought
of as a first step in I planned that to do a certain action
and I know I will take the next up after that. And then
of course I emphasize monitoring strategies are really important
to integrate into this entire process. Again while we are
not talking about those in detail, the fold into everything
I just talked about in terms of giving you good information, on
a temporal basis, get temporal data when you monitor
over time that understands -- that help to understand the dynamics
of the system and also your remedy functions. So, hopefully I hope
I have given you some picture of the types of factors
that I think are important, as we look at sites for
remedy selection, and implementation, I would be glad to take any
questions now if you have some.
>> Thank you.
>> All right thank you so very much. I will remind our live
audience if you have questions or comments
this presentation you can enter this into the Q&A window in the
bottom right corner of your screen.
I know a few of you were raising your hand electronically, and the
webinar, if you did not do that, don't worry you don't need to know
how to do that, a quick reminder that we
ask our attendees to type in their questions or comments. We don't
use the race had feature. So with that, -- the raised hand feature.
So with that let me start with the first question Mike, I think you
were just hitting home on this concept, and that was
one participant wanted you to talk more about the monitored portion
of MNA, I think you were just discussing
how significant that it can be in that whole
remedy picture. Are there other resources perhaps you might point
people to if they would like to learn more about the monitoring
element in MNA?
>> That is a great point, I agree monitoring is very important,
it's important for a couple of aspects, one of course is for things such
as MNA, that is the cost element, when you think about how you do
that monitoring, and how you manage the cost for that. And
then what information that you need to get from that monitoring the
helps you understand the dynamics of the plume. There are
good resources out there, the EPA MNA guidance is really excellent
I use that all the time, there is
also been technology resources out there, the DOE has put out
a document that talks about monitoring strategies, and some
of those more recent documents are talking
about a lot of times we think about monitoring in terms of monitoring
wells, collecting samples, of course that is important, but there are
some other monitoring technologies that are starting to emerge. I talked
about one of those, the tomography, there are
other approaches to help you manage the cost of monitoring, but also
help you focus in on the information that is
most diagnostic of the dynamics that are occurring. That are important
to the remedy management. I have actually a bunch of references
that included in my slide, I don't think I included some of
the monitoring once, I apologize for that, if you go out and do some
searching, or if you send me an email I would be happy to help with
the type of research that I use when thinking about monitoring
thank you for the question.
>> Excellent thank you. Our next question, says
in the example of treating uranium, in the vadose
zone applying phosphates, is a concern of further impacting groundwater
with on sequestered phosphate?
>> That is a good observation.
In any type of remediation, you have to think about
secondary effects, of any amendments you're going to use. And you
have to typically you are weighing that against the benefits that you
gain, from sequestering uranium for example but you have to think
about the secondary effects, and if there are ways to mitigate those.
So for the sequestration that we talked about,
it is not broadcast over a large area, it is a hotspot for the treatment,
so that limits the amount of phosphate impact, and we actually did some
work to look at the fate of phosphate, and this technology
was applied in a sequential faction, we did treat
ability test, and up to a first stage of a pigmentation where
we are just now looking at the second phase of implementation. It is a
very important factor, and was all amendments have some sort of
secondary effect. Reducing the subsurface, and therefore you
can cause a reaction to occur that directly is related
to the contaminant degradation.
Is something we have to think about for everything, I'm glad you brought
this up. I did not talk about this in my presentation perhaps I should've
is another factor we think about technology, what is the total chemistry
or hydraulic package that you get when you apply that amendment.
Good question thank you for pointing that out.
>> Thank you. I think somewhat similar to that, you had
brought up a point when you were looking
at uranium, that you had portions of it were mobile, versus some that
were nonmobile. In one participant,
they wanted to know if you have nonmobile uranium
don't you still need to address that? If it is posing a risk?
>> Yes that is correct. If it is in a location that is still posing
a risk, then that is correct, maybe what I will do
is I will use example, for uranium, I talked about the uranium that
we see in the groundwater at example site. We did some extractions, we
see uranium, in the sediment associating
facies. That is not immobile it will lead over time.
That is a concern, that is a risk.
It may create uranium contamination of the groundwater above levels
of concern.
So we would softer address act secondary source material, so that mass of
our uranium is the target, remediation. If you do not
have a direct pathway, where really our
exposure pathway is just groundwater impact. If I have a
uranium in the form like a silicates, that is
relatively immobile, or has very low leaching characteristics, and
is never going to put uranium out into
the water in high concentrations, the low
concentration of uranium will never create uranium above the level of
risk and the underlying groundwater's that is a different setting. Now
that might say that that uranium is already sequestered or attenuated,
and is not a risk. It depends on where we are
talking about, it is a good point, we cannot just assume that only
the aqua phases is a risk, and it's the precipitated phase
that is leachable enough to creates concentrations above a risk level.
Yes that is correct, that is a good clarification.
>> Thank you.
>> Wonderful. You were just talking about the vadose
zone, the participant wants to know more about the low and
dry air through the vadose zone.
Can you expand on that concept?
Sure, in Hanford we have a
relatively thick vadose zone about 75 meters thick, were in a fairly
arid site so the natural recharge is fairly
low. But when we discharge water to the vadose zone it got
wet. A lot of moisture went into the vadose zone, some of
that pushed all the way through to the groundwater even
if it did not there was residual water that is draining into the
groundwater. At a rate that is higher than if you think about
a desert. If you add water to the vadose zone, one of the technologies
we have tested out here, we have a number of publications on, is
to blow in dry air and that will evaporate that water the
water than essentially evaporates and
becomes humidity. So that humidity moves out, away from that zone where
we have injected the dry air,, the water does not
re-condense unless it is an area of different temperature.
During evaporation, the desiccation zone cools, we are
always moving from colder zones to a warmer son, essentially that
water stays as humidity, and moves out of the way and moves out to
the larger zone, it does not contain any contamination but we have dried
that vadose zone when we put the surface very
on top I don't have that remaining water that is going to draining
carry my contamination into the water at a high rate or rates higher
than I want. That is the basis of the technology, there are some reports
and I think I might've included some
of those in my list of references, if I have
not I will certainly be happy if you send me an email to provide
those, it looks like I did include those reports, there is a lot of
information about the technology in that report. That is the quick
version of how that works.
>> Arete excellent thank you so much. I don't see any more questions
in the life Q at the moment, that doesn't mean that we won't have
one or more coming into the queue, but perhaps in the interest of time
we will go back to our overview introductory material,
and I will let Cindy if you are still with
me on the line, perhaps we can advertise to the audience some of
the upcoming FRTR related events, and wait and see if we
have any other questions coming into the queue before we close out
things today. Cindy are you there?
Yes you -- yes, thank you. I want to point out that
we have a second session based on the last of
our meetings, the second webinar session that will be one month from
today, on March 28. That session will cover incremental sampling
methods for remediation of heavy metals
application of an in situ activated carbon amendment
for sediment and soil Mercury remediation and updates on research from NIH
national Institute Superfund research program.
>> The links that you see here, is for signing up for that webinar.
Just like you did for this one today.
>> We have one other thing that I would like to point out,
there is an in person meeting for FRTR coming
up. On May 9. 2018. This will be held at the Reston Virginia
USGS headquarters. The topic for that meeting is evolution of
sub- service remediation lesson learned from technical challenges
to achieving cleanup goals. Webinar participation
will be available also for those who are unable to meet this in person.
I want to thank our speakers, again, I will hand this back over to Jean
Balent to see if we have any other questions.
>> All right, as I suspected we did have one more
come in, I am going to read this question out loud, I believe Mike
that this question is directed to you, this participant wants to
know how does radium that in with the monitoring
risk assessment in remediation of other radio
nucleotides? -- Radionuclides? What we are
referring to, with the natural occurring materials, and
many sites, that is actually a driving factor. Have to admit I
do not have a lot of experience with that, at Hanford we have plenty
of [Indiscernible] sources, that overwhelm those considerations
for us. So unfortunately I do not have a lots of experience with that
although I do know that there is quite a bit of
literature about. -- on that topic.
Also related to naturally occurring radioactive
materials out there. I apologize, but that is
not really particularly what I've had expense
with yet.
>> I appreciate the information regardless. I do not
see any other questions or comments, in the queue. I think I am probably
going to go ahead and essentially walk through
a few final reminder items before we close things out today. What
I want to do well I have you here, do not hang up or leave yes
yet, there are a couple of quick reminders, a few of you did ask
if you could have copies of the presentation, I just want to
remind everyone that is available from the seminar resource. If you
look on the middle right of your screen you
should find a series of URLs in a box called related
URLs, scroll through that list of links look on the one assess
seminar resources and impress the brows to button that will allow
you to open up that website and access the materials that were presented
today. If you happen to be one of the lucky ones replaying the recorded
version of today's webinar, those links still
work in the archives of the you can go ahead and follow those links
and click on the buttons to access
our materials. Contact information for the presenters and organizers
can also be found in the seminar homepage, feel free to write me
if you have a specific question or comment or suggestions for
future webinars. I will ask if each of you could take a moment to fill
out our online feedback form there were nearly
150 individuals who joined us from all over the world today, we had
participants from as far as the UK, and even some American attendees
from Alaska, so thank you very much
or the widespread attendance. If each of you could follow the link
to the seminar feedback form and let us know what you thought of
today's delivery, both in the content that we presented, as well as the
method of delivery, I would very much appreciate it, it helps us
to continue to offer these types of sessions. One of the most frequently
asked questions I receive is if we issue [Indiscernible].
We do not issue those for our
sessions we do offer participation certificates.
Many of these are able to take these
participation certification along with the registration emails or
copy of the materials in the sessions and use that as argumentation to
verify their attendance and so good credit from whomever they are crediting
organization is. So if you want one of those participation certificates
you can get one by filling out that online feedback form. At the bottom
of the form there will be a box that as long as you check
that box which says that I certify that I attended this life Sieben
-- live seminar. Check that
box and send in the feedback form you will immediately have access
to one of these participation certificates you can print out or save for your
own records. If you participated in a group, each person can fill
out that feedback form, on their own, and can get their own
certificate even though you attended in
one computer. If you are replaying the archives you can still follow
the link to that feedback form and let us know what you thought to
get one of the certificates. So today's session was recorded, you
will automatically receive an email once the archived materials available
for on-demand playback and you are welcome to forward that to other
colleagues you think might find this useful. Is
any mention this is the first of the seminar series will be hosting,
I hope that you will be joining us next month as we host session
number two on March 28. at 1 PM Eastern time. With that I will echo
my thanks, to the speakers and organizers who helped put onto the session
and took time out of their busy schedules to join us and to the
hundred 50 of you from all over the world thank you so much for
joining us. This will be a formal conclusion for today's
live broadcast.