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The METS Process in Brief/2015

The METS remediation process equipment is about the size of a large SUV. It is fully mobile 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:

  1. 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.

  2. 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.

  3. 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.

  4. 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

  5. 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.

  6. 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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