Download or read book Countercurrent Stripping of Trichloroethylene from Contaminated Ground Water Using a Microbubble Air Dispersion written by Charles S. Sawyer and published by . This book was released on 1988 with total page 180 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Distribution and Movement of Trichloroethylene in Ground Water in the Tucson Area Arizona written by S. A. Leake and published by . This book was released on 1987 with total page 56 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Environmental Contamination Department of Defense Activities Related to Trichloroethylene Perchlorate and Other Emerging Contaminants written by and published by DIANE Publishing. This book was released on 2007 with total page 20 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Development of Packed Tower Air Strippers for Trichloroethylene Removal at Wurtsmith Air Force Base Michigan written by Randy L. Gross and published by . This book was released on 1985 with total page 89 pages. Available in PDF, EPUB and Kindle. Book excerpt: Packed-tower air stripping was researched and developed to treat trichloroethylene (TCE)-contaminated groundwater at Wurtsmith Air Force Base (Oscoda), Michigan. A leaking underground storage tank has caused a 1000 meters (3200 feet) long, 500 meters (1600 feet) wide, and 18 meters (60 feet) deep plume, with a maximum concentration approaching 10,000 ppb. While activated carbon could have produced treated water with an effluent TCE concentration below Michigan's 1.5 ppb discharge standard, the projected $1.5 million capital cost and the annual $400,000 operating and maintenance costs were prohibitive. At the request of HQ Strategic Air Command, the Engineering and Services Center investigated alternate groundwater treatment techniques. Laboratory studies were performed to determine removal efficiencies and mass transfer coefficients for TCE on 16 mm (5/8-inch) (and 25 mm (1-inch)) polypropylene Pall rings at various liquid and air flows, and at temperatures ranging from 10-30 C (50-86 F). Performance equations and removal efficiencies were combined to provide relationships for determining the required packing volume. Based on these studies, twin packed-tower air strippers were built onsite at Wurtsmith AFB. The strippers were performance-tested from May 1982 to May 1983, with removal efficiencies averaging better than 99.9 percent. Originator supplied keywords include: Aeration, Trichloroethylene, TCE, Pall Rings, Groundwater Treatment, Volatile Organics, Biological Growth, Air Stripping, Biological Degradation, Trichloroethene.

Download or read book Measuring the Removal of Trichloroethylene from Phytoremediation Sites at Travis and Fairchild Air Force Bases written by Heather A. Klein and published by . This book was released on 2011 with total page 113 pages. Available in PDF, EPUB and Kindle. Book excerpt: Past use of trichloroethylene (TCE) as a degreasing solvent for aircraft maintenance has resulted in widespread groundwater contamination at Air Force Bases around the world. Travis AFB in California and Fairchild AFB in Washington are evaluating phytoremediation as a treatment option, since trees have been reported to take up dissolved TCE from shallow groundwater and volatilize it to the atmosphere while enhancing the volatilization of TCE from surrounding soil. Previous studies generally focused on the identification of removal mechanisms. The emphasis of this research was to quantify total TCE removal from phytoremediation demonstration plots at Travis and Fairchild AFBs. Tree cores, collected using an increment borer and analyzed using headspace GC/MS, were used to determine the relative TCE concentrations within the plume beneath the trees and to estimate the mass of TCE in each tree. To estimate the iv volatilization of TCE from leaves, a small section of tree branch was placed inside a flow-through glass chamber. Continuous air flow through the chamber maintained normal transpiration and temperature. Air exiting the chamber was sampled for TCE using Tenax® tubes. Humidity probes placed at the chamber entry and exit were used to estimate transpiration. Volatilization of TCE from tree trunk and soil surfaces was measured by enclosing a section of trunk or ground surface within a small stainless steel chamber. Fans in the chamber mixed the air that was recirculated through Tenax® tubes to continuously remove TCE. After a measured time interval, the Tenax® tubes were analyzed for TCE by thermal desorption GC/MS. By using a Thiessen polygon method, the removal of TCE was estimated to be 839 g/yr at Travis and 18 g/yr at Fairchild with the majority from leaf and soil volatilization. Soil surface volatilization of TCE was greater inside the planted areas than outside the planted areas, indicating that the trees enhance this removal by this mechanism. Based on these estimates phytoremediation removed 5 and 50% of the mass of TCE in the groundwater at Fairchild and Travis Air Force sites, respectively.

Download or read book Use of Mini Sprinklers to Strip Trichloroethylene and Tetrachloroethylene from Contaminated Ground Water written by and published by . This book was released on 2003 with total page 15 pages. Available in PDF, EPUB and Kindle. Book excerpt: Berisford, Y.C., P.B. Bush, J.I. Blake, and C.L. Bayer. 2003. Use of mini-sprinklers to strip trichloroethylene and tetrachloroethylene from contaminated ground water. J. Env. Qual. 32:801-815. Three low-volume mini-sprinklers were tested for their efficacy to strip trichloroethylene (TCE) and tetrachloroethylene (PCE) from water. Deionized water spiked with TCE and PCE was pumped through a mini-sprinkler supported on top of a 1.8-m-tall. Water was collected in collection vessels at 0.61 and 1.22 m above the ground on support columns that were spaced at 0.61-m intervals from the riser base, and samples were composited per height and distance from the riser. Overall, air-stripping reduced dissolved concentrations of TCE and PCE by 99.1 to 100 and 96.9 to 100%, respectively. Mini-sprinklers offer the advantages of (i) easy setup in series that can be used on practically any terrain; (ii) operation over a long period of time that does not threaten aquifer depletion; (iii) use in small or confined aquifers in which the capacity is too low to support large irrigation or pumping systems; and (iv) use in forests in which the small, low-impact droplets of the mini-sprinklers do not damage bark and in which trees can help manage (via evapotransporation) excess waste water.

Download or read book Field Evaluation of Trichloroethylene Removal by Packed Column Air Stripping written by Michael D. Cummins and published by . This book was released on 1982 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Quantifying the Removal of Trichloroethylene Via Phytoremediation a Hill Air Force Base Utah Operational Unit 2 Using Recent and Historical Data written by J. Oliver Diamond and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Trichloroethylene (TCE) is a carcinogenic, chlorinated volatile organic compound that was commonly used as a degreasing solvent for aircraft maintenance at many US Air Force bases. Past improper disposal of TCE has resulted in contaminated groundwater at many of these facilities. Phytoremediation, defined as the use of plants and their associated microorganisms to stabilize or remove contamination, has been implemented as part of a TCE groundwater cleanup at Travis Air Force base near Sacramento, CA and is being considered as a remediation option at other bases. Volatilization of TCE from leaves and the surface of the soil near the trees were shown to be the most important removal mechanisms at the Travis site. Past studies conducted on indigenous trees growing above TCE contaminated groundwater at several Hill Air Force Base (HAFB) locations have also shown that TCE is taken up and volatilized by the trees. However, phytoremediation has not been implemented, in part because of the difficulty in predicting the potential effectiveness of TCE removal over time. Flow through or recirculating chambers were used to quantify the amount of TCE removed by volatilization through leaf, trunk, and soil surfaces. Tenax4́Ø sorbent tubes, used to collect TCE from the chambers, were analyzed by thermal desorption gas chromatography/mass spectrometry. Tree cores were collected using an incremental borer and analyzed by headspace GC/MS to quantify the TCE mass contained in the trees. Field measured transpiration stream concentrations (TSC) and groundwater data were used to calculate transpiration stream concentration factors (TSCF) for TCE. Comparing current and historical data, it was found that trees reach a steady state TSCF value of 0.26 after about 15 years. Using this information, it was predicted that a phytoremediation plot containing 40 poplar trees located in a seep area within HAFB OU2 would remove 4.82 kg of TCE annually. A larger plot covering the entire hillside above this seep (160 trees) could remove up to 19.28 kg of TCE annually, once trees reach a steady state TSCF.

Download or read book PACKED TOWER AIR STRIPPING OF TRICHLOROETHYLENE FROM DILUTE AQUEOUS SOLUTION written by James M. Gossett and published by . This book was released on 1983 with total page 38 pages. Available in PDF, EPUB and Kindle. Book excerpt: Air stripping is among the technologies being considered by the Air Force for TCE removal from contaminated groundwaters. The most promising stripper configuration is that of the countercurrent flow, packed column. This study was undertaken to model the performance of such a stripping reactor applied to TCE removal. Equations are presented which related efficiency to packed volume, air and liquid flows, gas/liquid partition coefficient (Henry's constant, H) and overall mass transfer coefficient (KLa). A major objective of this study was to quantify the effect of temperature and ionic strength on H, and of temperature, air flow and liquid flow on KLa. Henry's constant was measured by an equilibrium, mixed batch reactor technique, over a temperature range from 10 to 30 C, and a range of ionic strengths from 0 to 1 Molar Potassium Chloride. The effect of temperature was of practical significance; the effect of ionic strength was not. KLa was determined for 5/8 - inch (1.59 cm) plastic Pall rings over a range of temperature from 10 to 30 C. The effect was significant, and equations are presented for calculating the dependency. Air and liquid flow velocity did not affect KLa over the range examined. (Author).

Download or read book Application of Air Stripping Technology for the Removal of DBCP Residues in Community and Industrial Water Supplies written by and published by . This book was released on 1983 with total page 120 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Treatment of Chloro hydrocarbon Contaminated Ground Water by Air Stripping Process written by Sung-Woon Chang and published by . This book was released on 1990 with total page 248 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Removal of Trichloroethylene Contamination from the Subsurface written by and published by . This book was released on 1990 with total page 31 pages. Available in PDF, EPUB and Kindle. Book excerpt: Volatile organic compounds such as petroleum hydrocarbons and halogenated hydrocarbon solvents are common contaminants of the subsurface environment. Although immiscible with water, many of these organics have large enough aqueous phase solubilities to significantly degrade the quality of groundwater with which they come in contact. In addition, many of these substances exhibit high vapor pressures, causing them to partition strongly into the gas phase in their surroundings. Because of these properties, a volatile organic compound (VOC), once introduced into the subsurface may be transported as a solute, a vapor, or as a constituent in a non- aqueous phase liquid (NAPL). This implies that at some sits, an adequate description of the migration of these contaminants in the subsurface would necessarily involve three phases, -- gas, aqueous and NAPL. For example, to design an effective aquifer remediation scheme for a site where NAPL is present, it would be wrong to focus solely on the aqueous phase while ignoring either the gas phase or the NAPL phase. In the present work, we use a simulator developed by Falta et al. (1990a), known as STMVOC, '' which models true three-phase flow in which NAPL, gas and aqueous phases can move in response to pressure, capillary and gravitational forces. STMVOC is capable of handling three-dimensional, three-phase fluid flow with strong heat transport and the associated phased change effects. 16 refs., 5 figs., 4 tabs.

Download or read book A Case Study of Reductive Dechlorination of Trichloroethylene contaminated Groundwater at Offutt AFB by Use of an Organic Composite Biowall Lasagna Treatment written by Brian J. Christ and published by . This book was released on 2002 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Bio enhanced In well Vapor Stripping for the Remediation of Trichloroethylene Contamination written by Rahul K. Gandhi and published by . This book was released on 2001 with total page 866 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Biostimulation of Trichloroethylene in Contaminated Aquifers written by William J. Hickey and published by . This book was released on 1999 with total page 22 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Fate and Transport of Trichloroethane and Trichloroethylene Contaminated Groundwater Building 719 Dover Air Force Base Delaware written by Kenneth J. Melchiorre and published by . This book was released on 1996 with total page 208 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Effect of Natural Organic Matter Metal Ions and Nitrate on Electrochemical Dechlorination of Trichloroethylene written by Noushin Fallahpour and published by . This book was released on 2016 with total page 149 pages. Available in PDF, EPUB and Kindle. Book excerpt: Groundwater is susceptible to pollution due to improper waste disposal. Groundwater contamination continues to be a problem in areas where population relies on groundwater as a major source of drinking water. Development of technologies, such as in situ electrochemical transformation to clean contaminated groundwater is of great importance. Electrochemical systems, which mainly consist of two or more arranged electrodes that are immersed in wells in groundwater, are of interest because of their ability to manipulate redox conditions to transform contaminants into non-toxic forms. Aquifers in karst regions are very susceptible to contamination and present a significant exposure routes due to presence of fissures and channels that facilitate contaminant transport under high flow rate. Trichloroethylene (TCE), a toxic chlorinated solvent that causes major health problems, is present in many contaminated aquifers including many that reside in karst regions. Treatment of aquifers contaminated with TCE is difficult in the presence of other contaminants, such as chromate, selenate, and nitrate, which interfere with TCE transformation and degradation mechanisms. Moreover, presence of natural organic matter (NOM) in the groundwater can influence transformation of TCE and other contaminants. Therefore, it is important to evaluate transformation of TCE in the presence of contaminant mixtures in groundwater. In this study, a series of experiments are conducted to (1) evaluate of the effect of co-existing organic and inorganic compounds on the electrochemical dechlorination of trichloroethylene (TCE) in simulated karst media; and (2) assessment of the impacts of high groundwater flow rates in the presence of palladium (Pd) catalyst on TCE transformation rate and the accumulation of precipitates. A small-scale flow-through limestone column is used to simulate a karst aquifer media to evaluate dechlorination of TCE in the presence of organic and inorganic compounds. Iron anode was used to produce ferrous ions and promote reducing conditions in the column. Various current intensities (30, 60, and 90 mA) were applied under the flow rate of 1 mL min−1 and initial TCE concentration of 1 mg L−1. Under the same testing conditions, presence of chromate has the highest influence on TCE removal followed by selenate and then nitrate. The reduction of TCE under 90 mA current, 1 mL min−1 flow rate, and 1 mg L−1 initial TCE concentration, was inhibited in the presence of humic acids due to competition for direct electron transfer and/or reaction with atomic hydrogen produced at the cathode surface by water electrolysis. The use of iron anode creates favorable conditions for TCE reduction but produces aggregates in combination with ferrous ions, which may impact the long-term performance of the remedial system. A vertical acrylic column, with Pd pellets placed on the cathode surface, was used to investigate the impacts of Pd-based catalysis for the removal of TCE under high flow rate (1 L min−1). The effects of electrode materials and current intensities on precipitation, pH and ORP are assessed. The following electrode materials and arrangements were tested: (a) two MMO electrodes as an anode and a cathode, (b) a cast-iron anode and a MMO cathode, and (c) a cast-iron anode and a copper foam cathode. Current intensities of 500, 250, 125, and 62 mA were tested under the flow rate of 1 L min−1 and 5 mg L−1 of initial concentration of TCE. Under the conditions of 1 L min−1 flow, 500 mA current, and 5 mg L−1 initial concentration of TCE, removal efficacy using iron anodes (96%) is significantly higher than that of mixed metal oxide (MMO) anodes (66%) because the iron anode supports reduction conditions by electrolysis. Two types of cathodes (MMO and copper foam) in the presence of Pd/Al2O3 catalyst under various currents (250, 125, and 62 mA) were used to evaluate the effect of cathode materials on TCE removal efficacy. The similar removal efficiencies were achieved for both cathodes, but more precipitation generated with copper foam cathode. Palladium improved TCE degradation by 120% for 250 mA, 100% for 125 mA, 100% for 62 mA, under the conditions of using an iron anode followed by a copper foam cathode with 1 L min−1 flow rate. The high velocities of groundwater flow can have important implications since the groundwater flow rate can significantly fluctuate, especially in karst aquifers. The optimization of the electrochemical systems for successful operation under high flow rates allows the robustness and great flexibility for the application. It is assumed that the high flow rate would favor the transformation of contaminants since it would flush out precipitates and prevent clogging.