Valence state: The combining capacity of an atom or radical determined by the number of electrons that it will lose, add, or share when it reacts with other atoms.
free product: A NAPL found in the subsurface in sufficient quantity that it can be partially recovered by pumping or gravity drain.
aerobic: Direct aerobic metabolism involves microbial reactions that require oxygen to go forward. The bacteria uses a carbon substrate as the electron donor and oxygen as the electron acceptor. Degradation of contaminants that are susceptible to aerobic degradation but not anaerobic often ceases in the vicinity of the source zone because of oxygen depletion. This can sometimes be reversed by adding oxygen in the form of air (air sparging, bioventing), ozone, or slow oxygen release compound (e.g., ORC(r)).
Aerobic dechlorination may also occur via cometabolism where the dechlorination is incidental to the metabolic activities of the organisms. In this case, contaminants are degraded by microbial enzymes that are metabolizing other organic substrates. Cometabolic dechlorination does not appear to produce energy for the organism. At pilot- or full-scale treatment, cometabolic and direct dechlorination may be indistinguishable, and both processes may contribute to contaminant removal. For aerobic cometabolism to occur there must be sufficient oxygen and a suitable substrate which allows the microbe to produce the appropriate enzyme. These conditions may be present naturally but often in the presence of a source area oxygen and a substrate such as methane or propane will need to be introduced.
Adapted from US. EPA 2006 Engineering Issue: In Situ and Ex Situ Biodegradation Technologies for Remediation of Contaminated Sites
anaerobic: Direct anaerobic metabolism involves microbial reactions occurring in the absence of oxygen and encompasses many processes, including fermentation, methanogenesis, reductive dechlorination, sulfate-reducing activities, and denitrification. Depending on the contaminant of concern, a subset of these activities may be cultivated. In anaerobic metabolism, nitrate, sulfate, carbon dioxide, oxidized metals, or organic compounds may replace oxygen as the electron acceptor.
Anaerobic dechlorination also may occur via cometabolism where the dechlorination is incidental to the metabolic activities of the organisms. In this case, contaminants are degraded by microbial enzymes that are metabolizing other organic substrates. Cometabolic dechlorination does not appear to produce energy for the organism. At pilot- or full-scale treatment, cometabolic and direct dechlorination may be indistinguishable, and both processes may contribute to contaminant removal.
Quoted from US. EPA 2006 Engineering Issue: In Situ and Ex Situ Biodegradation Technologies for Remediation of Contaminated Sites
architecture: "Architecture" refers to the physical distribution of the contaminant in the subsurface. Residuals that take the form of long thin ganglia or small dispersed globules provide a larger surface area that will dissolve much faster than if the same amount of liquid were concentrated in a competent pool.
Sources: For purposes of this discussion, a DNAPL source zone includes the zone that encompasses the entire subsurface volume in which DNAPL is present either at residual saturation or as "pools" of accumulation above confining units. In addition, the DNAPL source zone includes regions that have come into contact with DNAPL that may be storing contaminant mass as a result of diffusion of DNAPL into the soil or rock matrix.
source zone: For purposes of this discussion, a DNAPL source zone includes the zone that encompasses the entire subsurface volume in which DNAPL is present either at residual saturation or as "pools" of accumulation above confining units. In addition, the DNAPL source zone includes regions that have come into contact with DNAPL that may be storing contaminant mass as a result of diffusion of DNAPL into the soil or rock matrix.
focal ulceration: The process or fact of a localized area being eroded away.
metaplasia of the glandular stomach: A change of cells to a form that does not normally occur in the tissue in which it is found.
hyperplasia of the glandular stomach: A condition in which there is an increase in the number of normal cells in a tissue or organ.
histiocytic: Degenerative.
duodenum: First part of the small intestine.
microcytic: Any abnormally small cell.
squamous cell papillomas: A small solid benign tumor with a clear-cut border that projects above the surrounding tissue.
squamous cell carcinomas: Cancer that begins in squamous cells-thin, flat cells that look under the microscope like fish scales. Squamous cells are found in the tissue that forms the surface of the skin, the lining of hollow organs of the body, and the passages of the respiratory and digestive tracts. Squamous cell carcinomas may arise in any of these tissues.
jejunum: The middle portion of the small intestine, between duodenum and ileum. It represents about 2/5 of the remaining portion of the small intestine below duodenum.
ileum: The distal and narrowest portion of the small intestine.
squamous: Flat cells that look like fish scales.
metaplasia: A condition in which there is a change of one adult cell type to another similar adult cell type.
ossification: The process of creating bone, that is of transforming cartilage (or fibrous tissue) into bone.
clastogenesis: Any process resulting in the breakage of chromosomes.
neoplastic: Abnormal and uncontrolled growth of cells.
ulceration: The process or fact of being eroded away.
leucocytosis: An elevation of the total number of white cells in blood.
neutrophils: A type of white blood cell.
chromodulin: A small protein that binds four trivalent chromium ions.
biomagnification: The increased accumulation and concentration of a contaminant at higher levels of the food chain; organisms higher on the food chain will have larger amounts of contaminants than those lower on the food chain, because the contaminants are not eliminated or broken down into other chemicals within the organisms.
exencephaly: Cerebral tissue herniation through a congenital or acquired defect in the skull.
everted viscera: Rotated body organs in the chest cavity.
To Be Considered: Documents, such as federal or state guidances, that are not legally binding but may be relevant to the topic in question.
gaining: A gaining surface water body is one where groundwater flows into it.
losing: A surface water body is losing when there is a permeable sediment bed that is not in contact with the groundwater allowing the surface water to seep through it.
fluvial: Of or pertaining to flow in rivers and streams.
lacustrine: Of or pertaining to a lake as in lacustrine sediments—sediments at the bottom of a lake.
lipid: Any class of fats that are insoluble in water.
lipophilic: Able to dissolve in lipids—in this case fatty tissue.
organelles: A part of a cell such as mitochondrion, vacuole, or chloroplast that plays a specific role in how the cell functions and membranes.
RfD: The RfD is an estimate of a daily exposure of the human population (including sensitive sub-groups) to a substance that is likely to be without "the appreciable risk of deleterious effects during a lifetime." An RfD is expressed in units of mg/kg-day.
autonomic: That part of the nervous system that controls non-conscious actions such as heart rate, perspiration and digestion.
ataxia: Lack of muscle coordination.
funnel-and-gate configuration: A system where low-permeability walls (the funnel) placed in the saturated zone direct contaminated ground-water toward a permeable treatment zone (the gate)
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Describes a demonstration project at a former pole treating facility located in Visalia, CA, and presents the results of injecting steam and oxygen into a creosote-contaminated DNAPL zone.
Discusses hydrous pyrolysis/oxidation (HPO), an in situ thermal remediation technology that uses hot, oxygenated groundwater to completely mineralize a wide range of organic pollutants. At a field demonstration of HPO during the summer of 1997, the groundwater was heated by steam injections and oxygen was added by co-injection of compressed air. Dissolved organic carbon levels increased in response to steam injections as a result of the enhanced dissolution and mobilization of the creosote into the heated groundwater. Elevated concentrations of partially oxidized organic compounds (i.e., phenols, benzoic acid, fluorenone, anthrone and 9,10-anthracenedione), decreased levels of dissolved oxygen, and isotopic shifts in the dissolved inorganic pool were indicators of partial to complete oxidative destruction of the creosote in the heated aquifer as a result of the HPO process.
The Jennison-Wright site in Granite City, IL, is an abandoned facility that engaged in wood treatment of railroad ties and wood blocks, using creosote, pentachlorophenol, and zinc naphthanate on the northern portion of the site. The northern portion of the site also had a railcar that contained waste and contaminated soil stockpiles, called Area H. Jennite, an asphalt sealant, was manufactured on the southern part of the site. The Jennite pit (a lagoon) was an on-site disposal pit where creosote wastes were dumped. Other areas in the southern part of the site included the 22nd Street Lagoon, the Jennite Building (which had 2 silos), a tank farm (including a buried railcar) and other operations buildings. As of early 2007, future cleanup activities include removal of the dioxin contaminated soils; removal of the Jennite Pit; Hydrogen Release Compound (HRC) injection and air sparging to treat the highly contaminated groundwater plumes; removal of the 22nd Street lagoon; completion of Area H cleanup; the process tank farm cleanup; and construction/operation of the hot water and steam flushing system to remove NAPLs from the groundwater.
The 20-acre site was operated as a utility pole treatment yard from the 1920s until 1980, and approximately 275,000 poles were treated at the site. Wood preservatives, including 2,500,000 gallons of creosote and 900,000 gallons of pentachlorophenol, were used and stored on site during site operations. In 1977, a slurry wall was built to slow contaminant migration in the shallow aquifer. Southern California Edison, the potentially responsible party, removed all facilities and 2,300 cubic yards of contaminated soil and disposed of it off site at an approved disposal facility. The site has a subsurface barrier wall and a groundwater extraction and on-site treatment system. Starting in 1997, a pre-design pilot-scale steam injection system was installed. It injected over 100,000,000 pounds of steam, which greatly enhanced recovery of pole-treating chemicals. In addition, a full-scale steam injection system was used over a 30-month period to remove and destroy over 150,000 gallons of contamination from the site. Once the subsurface temperature dropped below 70°C, vadose zone bioventing and saturated zone biosparging operated with continued groundwater pump and treat from June 2000 until March 2004. Following the 2005 5-year review, contaminated surface soil to 10 feet below grade was removed in July 2006 and verified with confirmatory sampling to be below the prescribed cleanup standards. The final site closeout report was signed on May 19, 2009. Additional information: In Situ Destruction of Contaminants via Hydrous Pyrolysis/Oxidation: Visalia Field Test (1998); Innovative Technology Summary Report: Hydrous Pyrolysis Oxidation/Dynamic Underground Stripping (2000).
Innovative Technology Summary Report: Hydrous Pyrolysis Oxidation/Dynamic Underground Stripping
(1998); Innovative Technology Summary Report: Hydrous Pyrolysis Oxidation/Dynamic Underground Stripping
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