The METS Process in Brief/2021 The METS remediation process
equipment is fully mobile, radio controlled and
self-propelled. Previously excavated soil is deposited in the hopper at
the top of the apparatus by a conventional front-end loader. Very large
debris, such as rock, concrete or asphalt, is usually screened off at
the hopper opening. From the hopper, the soil is transferred in a
regulated flow to a custom designed processing mill. The mill impacts
and shreds the soil, while blending a treatment solution (chemical,
biological, or both), along with air and moisture, into the soil using a
method that is proprietary to EarthWorks Environmental. The contaminant
molecules in the soil are already being degraded or neutralized by the
time the soil emerges from the processing mill. The treated soil may be
deposited directly to the ground from the mill. However, the apparatus
includes a conveyor system at the back end, which may be used to deposit
the soil in locations and configurations as desired or to meet site
space constraints.
Technical
Principles Explaining METS Reliability
The METS process is designed to
meet all of the critical requirements for a successful soil remediation
technology (i.e., one that produces "non-detect" results from
today's standard soil testing methods, consistently and quickly), which
are:
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Ability to apply a wide
variety of proven chemical and biological remediation treatment
products that are available today, as well as those yet to be
invented.
Virtually any contaminant is susceptible to being
degraded or neutralized at the molecular level by a chemical
reaction or digestion by microbes. A great deal of research and
development has gone on, and continues to go on, with the objective
of finding or creating specific treatment products based on this
principle. It is not as widely known that such products have already
been created and, in some cases, are already in commercial use. For
reasons that will be explained shortly, these products have not been
used reliably or extensively for remediation of contaminated soil,
prior to the commercialization of METS.
An example of such a
commercially available product (as described in its patent: P/N
5,478,389) is a composition of a soluble silicate (in this case,
sodium silicate), an anionic surfactant (an ester of organo-phosphoric
acid), and a polyol (ethylene glycol), among other ingredients. The
product is used most commonly today to degrade hydrocarbons as part
of various cleaning and degreasing applications (for example, in
maintenance or emergency spill treatment activities at oil
refineries). The details of the chemical reactions involved are
proprietary and confidential, but the reactions are complex and, to
a large extent, occur simultaneously. The reactions begin
immediately upon application, quickly enough to inhibit the
volatilization of any toxic components into the atmosphere before
the degradation process is completed We have found that this
product, when modified for our process, works as effectively in
degrading hydrocarbon contamination in soil as it does in the
cleaning or degreasing applications.
Another example of products
based on a chemical reaction strategy are practical implementations
of a well-understood chemical principle known as Fenton's Reagent
Chemistry. FRC provides for direct oxidation -- release of nascent
oxygen -- via an exothermic reaction between a peroxide and a
catalyst. The exothermic reaction as well as oxygen release,
dependent upon catalyst, degrades the hydrocarbon molecule to its
carbon and hydrogen elements. The nascent oxygen reacts with these
elements to form benign compounds (for example, in the case of
gasoline, the byproducts are water and carbon dioxide). Chemical
reactions based on this chemistry are reliable and predictable, once
the proper environment has been created.
Researchers in a variety of
organizations and enterprises have identified and cultured microbes
that are proven to degrade and/or neutralize various types of
contaminants. In all known cases, these are naturally occurring
biological organisms that have been found to thrive in environments
where these contaminants have been introduced by man-made events or
by natural causes. Not all of these discoveries have led to
commercially available products, but we have been cataloging them
for compatibility with our process, and are confident that we will
have no problem obtaining practical access to such
"products" even if they are not yet on the open commercial
market.
In short, the means to
degrade, destroy and/or permanently neutralize contaminant compounds
exists today. We do not believe that there is any form of
contamination that is forever immune to chemical and/or biological
treatment.
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Inconsistencies in soil
conditions and content requires excavation and proper processing to
create a consistent and predictable soil matrix.
The primary
reason that the products described above have not been widely used
to remediate contaminated soil, is the lack of an effective,
reliable and versatile method for introducing reagents into a stock
of soil. Soil conditions found in nature can vary significantly
within a matter of a few feet, or even a few inches (vertically and
horizontally). Soil naturally varies in its composition (e.g., clay,
sand, hardpan, gravel, etc.), compaction, acidity, moisture content,
etc. Moreover, a stock of soil can contain a variety of materials
such as rock, wood, metal debris, etc., which are capable of
obstructing the free flow of air and moisture.
Nevertheless, most of those
who have been developing and promoting soil remediation
technologies, from vapor extraction, sparging, bio-injection,
thermal treatment, soil-washing, etc., have operated on the
assumption that this variability is not a significant constraint on
the effectiveness and efficiency of such technologies. Yet these
technologies have not been effective in removing or neutralizing
contamination, except under controlled conditions, or with
incomplete results, or through intervention with highly expensive
and/or slow acting processes. In fact, in our view, the only
credible and meaningful success stories associated with these
technologies (especially bioremediation) is where they have been
applied to create barriers in front of contaminant plumes.
We have determined, after
several years of research and practical experience with a variety of
these technologies, that this variability of soil conditions and
content is the principal, if not sole, barrier to effective and
efficient remediation of contamination-saturated soil. We believe
that for any remediation technology to be considered viable it must,
first and foremost, have a means of eliminating this variability in
the soil, in conjunction with introducing one or more chemical/
biological reagent(s). Second, the method for rendering the soil
into a homogenous matrix must reduce the soil to a fine particle
state in order to maximize access to the contaminant molecules.
Third, the method must have a means of ensuring that the reagent(s)
is evenly distributed throughout this homogenous soil matrix, and
allowed to complete the degradation/neutralization process, before
the soil loses its homogenous and fine particulate composition.
Finally, to promote speed and
efficiency, the soil matrix should include, at least initially, a
relatively high level of air entrainment and a carefully calibrated
level of moisture content. These are efficacious conditions for
promoting and sustaining the desired chemical reactions; they are
even more critical for a treatment regime based on biological
organisms. We have found for example, that bioremediation methods
that do not create these conditions (homogenous matrix, fine
particulate, effective distribution, air entrainment and proper
moisture) can take many months to show meaningful results, and may
take years to achieve remediation objectives (perhaps requiring
periodic re-injections of the biological reagents). However, with
our process, meaningful results using biological organisms can be
seen within hours, and remediation objectives achieved within a few
weeks.
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Adaptation of existing soil
processing technology to create a homogenous, fine particle soil
matrix.
Knowing that successful remediation technologies would
depend upon effective soil processing technologies -- i.e.,
technologies that (1) create a homogenous soil matrix consisting of
fine particle soil elements; (2) ensure even distribution of
chemical/biological reagents; (3) promote air entrainment; and so
forth -- we began researching and evaluating possible candidates. We
did not consider inventing such a technology because we did not
believe it would be necessary to do so. In addition, we did not want
our process design to be hampered by uncertainties about the
performance of such a critical element.
We did not find such
candidates in the environmental remediation industry. We did,
however, find many attractive candidates, presenting various
combinations of strengths and weaknesses for our purposes, in the
mining, sand-and-gravel and agricultural equipment industries.
Processing and treatment of soils and soil content is, of course, a
vital element in mining and sand-and-gravel operations, and in
agriculture. In addition, we found similar technologies starting to
become more common in the demolition industry (for materials
processing) and some other industries far removed from, or at least
outside the understanding of, the environmental remediation
industry.
It does not serve the
purposes of this paper to detail this part of our investigation. It
should be sufficient to say that we not only researched these
technologies, but also in certain instances made practical
application of them to the purpose of remediating contaminated soil
or simulations thereof. As a result, we were able to identify the
best technology, its commercial embodiments and the basis for
modifying it to meet our objectives.
It should be noted, in the
interest of proper disclosure, that we are not the only company or
inventor who has identified the need for or usefulness of soil
processing equipment, of one type or another, to environmental
remediation. We know of others who have attempted to commercialize
inventions based on this insight, and we are also familiar with a
variety of patents that have been issued, which contain references
to the use of such equipment for environmental remediation. We do
not, however, know of any other company or inventor who has
succeeded in developing a practical and commercially proven process
that meets all of the criteria for success that we identified,
especially the ability and knowledge base necessary to remediate a
wide range of contaminant types in a wide range of soil conditions,
with efficiency and reliability.
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Proper integration of
chemical/biological treatment reagents with the soil processing
mechanism.
As noted above, it is a necessary but not sufficient
condition for success that the soil be processed into a homogenous
matrix of fine particle soil elements. In addition, there has to be
a means for evenly distributing the chemical/biological reagent(s)
throughout the soil while it is in this homogenous state. In order
to meet this objective, we again conducted research into
commercially available technologies that could be adapted to the
purpose. We were able to identify a number of promising candidates,
primarily in the agricultural equipment industry. In this industry,
of course, it is desirable to obtain even distributions of
chemicals, nutrients, and organic materials, into soil. The
modifications required for our purposes were minor and involved
minimal invention on our part.
It is worth noting that a key
principle of our design is also what differentiates our process to a
critical degree from other attempts at superficially similar
remediation technology inventions. That is, our process distributes
the reagents precisely at the point that the soil is entering the
processing mechanism that produces the homogenous matrix. As a
result, the reagents are being distributed throughout the
contaminated soil at the exact moment that they are activated for
the degradation/neutralization process. In addition, this is also
the optimal stage for air entrainment and moisture control. Other
remediation inventions have attempted to introduce the reagents some
substantial time before or after the soil has been processed and, as
a result, achieved inconsistent or unreliable results, including
having to re-treat the soil. In our system, the reagent(s) is
already in the process of degrading/neutralizing the contaminant
molecules the moment that the soil exits the processing equipment
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Ability to treat multiple
contaminant types at the same time.
Many remediation projects,
particularly on industrial or military property, are hampered, if
not completely stymied, by the fact that the soil is contaminated by
more than one pollutant/hazardous material. For example, a stock of
soil might be contaminated with gasoline and soluble lead. All of
the problems and challenges, that make remediating a single
contaminant type so difficult and unreliable, are compounded when
multiple contaminants are present (in fact, most other remediation
technologies would be hard-pressed to efficiently remediate soil
contaminated with even two different hydrocarbon types, such as
gasoline and motor oil).
The ability to treat soil
containing multiple contaminant types in the same reliable,
efficient, affordable process, was not a critical objective of our
research and development effort. However, we quickly discovered that
the technologies we identified, and the processes we designed, were
easily and readily adaptable to treating multiple contaminant types
during a single pass through the process equipment. In fact, the
modifications required to achieve this result are trivial.
Essentially, they involve installing a series of separate storage
and distribution systems acting in parallel, each of which applies a
different reagent to the soil (for example, one reagent to degrade
the diesel fuel, another reagent to neutralize the soluble lead) at
the same time. There is no practical limit to the number of reagent
delivery systems involved, and therefore number of contaminant types
that may be treated in this way, other than constraints on the
desired physical size of the processing equipment.
On the other hand, we
recognize the possibility that, in certain circumstance, activities
by one reagent may hamper or block the actions by another (for
example, a chemical reagent might be harmful to, or inhibit a
biological organism until the chemical reactions are completed).
Those situations, which we think will be rare, would be identified
in laboratory testing prior to field application. In that event, the
simple solution would be the run the soil through the process
equipment a second time.
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The process is a complete
system, not just a piece of equipment or a treatment product.
We
have designed METS to be a fully commercial offering. That is, we
wanted an owner/operator of the system to be readily able to treat a
typical soil contamination problem, of any size, within a matter of
days after training, and to have the ability to reasonably estimate
the amount of time, labor, reagent, etc., required to complete the
project. We intend to license the METS technology to other companies
who themselves have little knowledge of the principles involved in
the design of METS.
In order to achieve these objectives, we created a
process that encompasses and standardizes all the phases in the
lifecycle of a complete remediation project. This lifecycle
encompasses testing of the soil for contaminant and soil conditions,
through selecting the optimum chemical and/or biological reagents,
to calibrating and adjusting the adjustable components of the
process equipment, to properly loading the contaminated soil and
depositing the remediated soil, to testing the remediated soil at
intervals of time, to recording the results back into a standard
database. The information gathered in the data is then available to
better inform future remediation projects having similar
characteristics.
As a result, the successful
operation of METS does not require active involvement from the
inventors of the process equipment, nor does it require the presence
of highly trained technical professionals.
Conclusion
METS is a commercial reality
today. The explanation of the METS process may seem surprisingly simple
to those who have been frustrated by the failure of other remediation
technologies. The trend in recent years has been to adopt remediation
technologies that contain a high degree of engineering complexity and
expensive, custom-designed components. Nevertheless, the simplicity of
the technical concepts underlying the design of the METS process, is
part of the reason why it is so powerful. This is also why METS is the
only fully commercial technology, existing today, that can treat such a
wide range of contamination problems faster and at a lower cost than any
other active method of remediation, including landfilling (i.e.,
"dig-and-dump").
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