"Innovative Environmental Technologies, Inc. has developed processes and methods based on the over 500 sites it has designed and implemented remedial solutions for since 1998.", says Michael Scalzi, President of IET. "Establishing an in-house collection of our own and licensed IP separates us from the industry as a technology leader and innovator. The integration of unique and sustainable organic hydrogen donors with and without zero valent iron has been demonstrated to be the most efficient and cost effective solution to remediating many chlorinated compounds".
Various species of Seaweed including Ascophyllum nodosum, Dulse, Nori, and Kelp contain substantial nutrients, beneficial to anaerobic processes. Seaweeds are available in a variety of forms including sheets, meals, flakes and powders that can either be hydrolyzed for solubility or remain insoluble as a slow release remedial product. In addition, dried seaweed can come in various sizes ranging from large granules characteristic of insoluble kelp meal to high mesh sizes of fine powder. The dynamic nature of seaweed has resulted in its wide use in varying commercial fields. Liquid seaweed extract as well as insoluble and (hydrolyzed)
The chemical composition of seaweeds allows for the contribution of stimulatingis comprised of fatty acids, carbohydrates, and proteins. Their concentrations of vitamins B2, and B12 in particular make seaweed an excellent alternative for environmental remediation. The species Ascophyllum nodosum contains high levels of enzymes, 17 amino acids, macro and micronutrients, plant hormones (auxins, cytokins, gibberillins)
Chlorinated solvents are the most common class of ground water contaminants at hazardous waste sites in the U.S. In a list of the top 25 most frequently detected contaminants at such sites, the Agency for Toxic Substances and Disease Registry (ATSDR) found that 10 of the top 20, including two of the top three, were chlorinated solvents or their degradation products. National Research Council, Alternatives for Ground Water Cleanup (National Academy Press, Washington, D.C. 1994). In fact, the same survey found that the most common contaminant, trichloroethylene (TCE), is present in more than 40% of National Priority List sites. The remediation of ground water contaminated by these compounds often presents unique obstacles related to their inherent characteristics, including hydrophobicity and high density. Many commercial process utilize raw vegetable oils and emulsions which co-elute the targeted solvents within the treatment liquid masking the presence of the compound targeted for treatment rather than stimulating the mineralization of said compound.
Natural attenuation of chlorinated solvents by reductive dechlorination often occurs at sites where an electron donor (food source or substrate for microbes) is present along with the chlorinated solvent contamination. As dissolved oxygen and other electron acceptors become depleted some microbes are capable of using the chlorinated solvents as electron acceptors. For selected compounds such as chlorinated ethylenes sequential dechlorination to a harmless byproduct ethylene can be achieved under favorable environmental conditions (EPA/600/R 10 98/128 September 1998).
In recent years efforts have been made to produce this anaerobic treatment effect by injection of electron donor into the subsurface. An overview of these technologies can be reviewed in the EPA document Engineered Approaches to In Situ Bioremediation of Chlorinated Solvents: Fundamentals and Field Applications (EPA 542-R-00-008 July 2000). Other inorganic and organic compounds can be degraded or immobilized under anaerobic conditions including selected toxic metals, nitrate, and MTBE. For sites that do not have sufficient amounts of natural electron donors to drive anaerobic natural attenuation, injection of microbial substrates has proven to be a cost-effective treatment or plume migration control measure. The microbial substrates can be injected into the contaminant source area where residual contamination is adsorbed onto soils or injected in a line across a ground water contaminant plume to form a permeable reactive wall to prevent further contaminant migration.
A wide variety of sugars, alcohols, organic acids, and even molecular hydrogen have been used successfully as electron donors to enhance anaerobic biotransformation processes. Most of these compounds are rapidly consumed after injection and must be replaced by either continuous low concentration delivery systems or with frequent batch additions of additive solution. Contaminant source areas can not be effectively removed or even precisely located for many ground water contaminant plumes. The presence of residual chlorinated solvents adsorbed onto soils or present as dense non-aqueous phase product (DNAPL) serves as an example of persistent ground water plume source areas that can last for many decades.
Recent interest has developed in the use of materials that slowly biodegrade or slowly release organic matter into ground water over time. A variety of vegetable oils have been demonstrated to be effective electron donors to stimulate anaerobic biodegradation. Although edible oils such as soybean oil have a much lower viscosity than a semisolid product, distribution in saturated soils is difficult. Soybean oil has a viscosity approximately times higher than water, which results in multiphase fluid flow and potential oil blockage of soil porosity. Injection of pure oil or large droplets of emulsified oil blocks soil pores producing treatment zones that are ineffective because they prevent free flow of ground water through the oil treated area. Injection of pure soybean oil into porous soil media has been shown to reduce water permeability by up to 100%.
In addition to slowly biodegradable hydrogen sources, soil and groundwater remediation process that utilize zero-valent metals have been applied with varying success. In the second embodiment of the invention, the addition of zero-valent metals to the micro dried seaweed or kelp allows for maintained reducing conditions resulting in greater longevity of the reactive metal surface. Zero-valent metal particles have been proven to effectively degrade halogenated solvents. For example, the mechanism and reaction rates of which iron reduces chlorinated aliphatics has been studied extensively due to iron’s low cost and low toxicity. Additionally, the pathways of the dehalogenation of DNAPL’s such as TCE have been proposed. TCE undergoes hydrogenolysis where the replacement of each of the three chlorines occurs sequentially. TCE reduces to cis-1 ,2-dichloroethene, trans-1 ,2-dichloroethene, and 1,1 - dichloroethene.