Innovative and Emerging Remediation Technologies
This page contains descriptions of new and emerging technologies for the remediation of contaminated soil and water. The chemicals of concern (COCs) commonly removed by a given technology are listed. This list may not be all-inclusive and all COCs listed will not necessarily be removed in all situations. An understanding of the technology, the COCs to be removed, and the conditions under which the technology is to be applied are all necessary to assess the feasability of the technology for a specific application.
The technologies are listed alphabetically by technology as well as by contaminant(s) removed. A brief description of each technology is also provided. If you know of a technology that you think should be included in this list, please contact us.
Disclaimer: Many of these technologies (or variations thereof) are protected by patents and require a license to use. PRIMA Environmental is not familiar with all patents or about the details of any such patents and assumes no legal responsibility for the improper use of these technologies under any patents, where applicable, or any representations relating to these technologies or patents covering such technologies. These descriptions are of a general nature and are provided only as a guide. PRIMA Environmental does not guarantee the comprehensiveness of any description provided or its applicability to a particular site or process. The publication of these descriptions is not intended to constitute a contract of a
ny kind and does not create any express or implied contractual obligation.
ALPHABETICAL LISTING OF NEW AND EMERGING TECHNOLOGIES
TECHNOLOGIES ACCORDING TO CONTAMINANTS REMOVED
| Contaminant |
Potentially Suitable Technologies* |
| Arsenic |
AD-33, EnviroBlend® , SMI-III™, Zero-valent Iron |
| BTEX |
Fenton's reagent, hydrogen peroxide, ozone, persulfate |
| MTBE |
Fenton's reagent, ozone, persulfate |
| Petroleum Hydrocarbons (eg. TPH-g, TPH-d) |
Fenton's reagent, ozone, persulfate |
| Chlorinated ethenes (PCE, TCE, DCE, VC) |
Fenton's reagent, ozone, permanganate, zero-valent iron, SMI-III™ |
| Chlorinated ethanes (eg. TCA, DCA) |
Fenton's reagent, possibly zero-valent iron and SMI-III™ |
| Halogenated pesticides (eg DBCP, Aldrin, Dieldrin) |
Fenton's reagent, ozone, permanganate, zero-valent iron |
| Hexavalent Chromium, Cr(VI) |
Ascorbic acid, BSP Cascade®, cheese whey, molasses, SMI-III™,
zero-valent iron |
| Metals |
AD-33, EnviroBlend®, SMI-III™ |
| Nitrate |
SMI-III™, zero-valent iron |
* Technologies listed are generally effective toward the specified compound or class of compounds under "normal" conditions. However, the technologies may not be effective toward all compounds in a class or in all matrices (eg, very corrosive water or in the presence of interfering substances).
TECHNOLOGY DESCRIPTIONS
AD-33 Media
AD-33 is an iron oxide-based adsorption media developed by AdEdge Technologies, Inc. for the removal of arsenic from water. According to product literature, AD-33 had a high arsenic capacity, can remove both As(III) and As(V), is simple to use, and is effective over a wide pH range.
Ascorbic Acid
(Vitamin C).The scientific literature describes the use of ascorbic acid for the treatment of acute chromate poisoning. Detoxification occurs via reduction of Cr(VI) to Cr(III). Laboratory testing conducted by PRIMA Environmental has shown that ascorbic acid can reduce Cr(VI) in groundwater.
BSP Cacasde®
(Calcium Polysulfide). BSP Cascade®is a dark orange-red liquid with pH ~ 11. It was developed by Best Sulfur Products to treat Cr(VI) and heavy metals in soil and water. Metals are generally stabilized via precipitation as water-insoluble compounds, while Cr(VI) is removed via reduction and precipitation.
Cheese Whey
Cheese whey is a product of cheese manufacturing and has been used in situ to reduce hexavalent chromium in groundwater.
EnviroBlend®
EnviroBlend®powders can be added to soil or process streams to stabilize metals such as arsenic, cadmium, chromium, lead, mercury and zinc to prevent leaching. EnviroBlend®is distributed by American Minerals Inc.
Fenton's reagent (classical)
"Classical" Fenton's reagent is an acidified mixture of hydrogen peroxide and ferrous iron whose exceptionally strong oxidizing ability was first identified in H.J.H. Fenton in 1894. It effectively oxidizes a wide range of compounds including BTEX, MTBE, TBA, petroleum hydrocarbons, chlorinated solvents as well as natural organic matter. It can be used to treat both soil and water matrices, although water quality and the ability to effectively deliver the reagent may limit its usefulness in some cases. Factors to consider when assessing the feasibility of Fenton's reagent include the formation of off-gases (1L of 1% hydrogen peroxide produces approximately 3L of oxygen gas), the formation of heat, and the need to reduce pH (at least temporarily) to pH < 4. Fenton's reagent decomposes to oxygen and water. Contaminants can be completely oxidized to carbon dioxide and water.
Fenton's Reagent (variations)
Several variations of Fenton's reagent exist in which hydrogen peroxide is combined with a catalyst other than acidified ferrous iron. Most of the catalysts are proprietary and are designed to work at near-neutral pH. One such catalyst is VTX, a metal-based catalyst developed by Advanced Oxidation Technology.
Hydrogen peroxide
Hydrogen peroxide (H2O2) is a weaker oxidant that Fenton's reagent. However, it is possible that in some cases, metals naturally present in water or soil could serve as catalysts, enabling Fenton-type chemistry to occur. Very low doses of H2O2 could also potentially enhance aerobic biodegradation since peroxide decomposes to oxygen gas and water.
Molasses
Diluted molasses has been added to the subsurface to reduce Cr(VI).
Ozone
Ozone (O3), a gas, is a strong oxidant that can react with a wide range of organic compounds, including chemicals of c
oncern as well as natural organic matter. O3 may react directly with contaminants or, in the presence of metals such as iron, react indirectly through the formation of hydroxyl radicals. Because ozone is non-selective and because mass transfer of contaminants into the gas phase (or ozone into the aqueous phase) is inefficient, determining an appropriate ozone dose a priority is not possible. Ozone decomposes into oxygen and water. Contaminants may be completely oxidized to carbon dioxide and water.
Permanganate
Permanganate (MnO4-) is a moderately strong oxidizing agent that is available as the solid potassium permanganate (KMnO4) or as liquid sodium permanganate (NaMnO4). It is most commonly used to oxidize chlorinated ethenes such as tetrachloroethene, trichloroethene, dichloroethene and vinyl chloride, and has been shown to remove the pesticides Aldrin and Dieldrin from soil and water. However, it is generally ineffective toward chlorinated ethanes (eg. trichloroethane or dichloroethane), benzene and other petroleum hydrocarbons. MnO4- reacts slowly with natural organic matter and other oxidizable spe
cies in soil and water, and in many cases, the soil oxidant demand (SOD) rather than the contaminant mass, determines the amount of MnO4- that will be required at a site. MnO4- can also oxidize soil chromium to water soluble hexavalent chromium, Cr(VI). In some cases, this Cr(VI) will naturally attenuate, while in others, the Cr(VI) may persist. Finally, MnO4- can either increase or decrease the permeability of a site, depending upon the concentration used, the formation of manganese oxide, the type of soil and the form of the MnO4- salt (Na+ or K+).
Persulfate
Persulfate (S2O82-) is a very strong oxidant that has been widely used in industrial processes and commercial products. It is attracting interest within the environmental community as for the chemical destruction of organic compounds such as BTEX, MTBE, chlorinated solvents and PCBS from soil and water. In most cases heat, metal ions (eg. Fe2+) or another catalyst is needed to achieve oxidation.
Sulfur-Modified Iron (SMI-III™)
SMI-III™ is a patented, granular media that has been developed for removal of arsenic(III), arsenic(V), nitrate, Cr(VI), metals, and chlorinated solvents from water. It is NSF Standard 61 Certified for use with drinking water and may be used alone or in conjunction with traditional adsorption media. Spent SMI is recyclable. The mechanism of contaminant removal depends upon the contaminant. For arsenic and metals, removal occurs via adsorption. For Cr(VI), removal may occur by adsorption of Cr(VI) or by reduction of Cr(VI) to Cr(III), followed by adsorption or precipitation of Cr(III). Removal of nitrate occurs via chemical transformation (reduction) to ammonia and other, unidentified products (1). Although nitrite may be an intermediate in this transformation, it has not been detected. Chlorinated solvents are presumably removed via reductive dechlorination.
VTX
VTX is a proprietary, non-toxic liquid catalyst developed by Advanced Oxidation Technology, Inc. for use with oxidants such as hydrogen peroxide, ozone and persulfate at near-neutral pH. Field and bench tests have shown that VTX, combined with a suitable oxidant, can treat many recalcitrant compounds including TCE, PCE, MTBE, 2,4-D, and BTEX.
Zero-valent Iron (Fe0)
The ability of zero-valent iron to remove chlorinated solvents from aqueous solution is well established. Removal is destructive and is believed to occur via reductive dehalogenation, in which a chlorine atom is replaced by a hydrogen atom. For polyhalogenated compounds, the reaction can continue until all halogens have been removed. Fe0 can also reduce other halogenated compounds including 1,2-dibromo-3-chloro-propane (DBCP) as well as inorganic compounds such as nitrate and Cr(VI). Fe0 may also sorbs metals such as arsenic. Fe0 is most frequently used for in situ, passive remediation of groundwater. In the simplest application of this technology, a permeable reactive barrier or iron wall is installed by digging trench perpendicular to the direction of groundwater flow and back-filling it with iron
. COCs are removed as the groundwater flows through the permeable barrier.
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