Determination Of Chlorinated Solvent Contamination In An Upward Flow Constructed Wetland
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Determination Of Chlorinated Solvent Contamination In An Upward Flow Constructed Wetland
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Author : Bryan C. Opperman
language : en
Publisher:
Release Date : 2002-03-01
Determination Of Chlorinated Solvent Contamination In An Upward Flow Constructed Wetland written by Bryan C. Opperman and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2002-03-01 with Constructed wetlands categories.
The purpose of this study is to determine chlorinated solvent contamination levels in an upward flow constructed wetland at Wright-Patterson Air Force Base (WPAFB), Ohio. A stratified grid sampling methodology will be used in sampling the contaminated groundwater. Analysis will be accomplished by means of purge-and-trap gas chromatography. The contaminant concentration levels will be used to enhance the design and construction of man-made wetlands used to remove chlorinated solvents from aquifers. PCE levels declined from an average of 33.97 ppb in the inflow stream to an average of 3.65 ppb in the upper layer, a 91% reduction. High concentrations occurred in areas where high hydraulic pressure gradients and hydraulic conductivities combined to allow contaminated water to migrate to the upper layers of the wetland with minimal contact time for reduction. Removing these areas from the data set increased the PCE reduction efficiency to nearly 98% with an upper level concentration average of 0.84 ppb. Trichloroethene (TCE) inflow rates averaged 0.63 ppb while TCE concentrations in the upper layer averaged 0.175 ppb. TCE concentrations peaked in the middle layer of the wetland suggesting that reduction of PCE was occurring there and in the bottom layer.
Characterization Of Chlorinated Solvent Degradation Profile Due To Microbial And Chemical Processes In A Constructed Wetland
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Author : Teresa A. Sobolewski
language : en
Publisher:
Release Date : 2004-03
Characterization Of Chlorinated Solvent Degradation Profile Due To Microbial And Chemical Processes In A Constructed Wetland written by Teresa A. Sobolewski and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2004-03 with Chlorination categories.
Perchloroethene (PCE) and its degradation products are among the most common organic groundwater contaminants in the United States. Constructed wetlands are a relatively new approach to dealing with this contamination problem. With their upward flow capability it is possible to introduce an aerobic and anaerobic environment with a consortium of microorganisms available to degrade the contaminants to within acceptable levels established by the Environmental Protection Agency (EPA). This study is a follow-up to the previous two years of research on PCE degradation in cell 1 at Wright-Patterson Air Force Base. This thesis was conducted in order to study the wetland and determine the mechanisms that exist to degrade the chlorinated solvent contamination that is present. It also provided additional evidence that the constructed wetland is degrading PCE to its innocuous byproducts. A purge-and-trap gas chromatograph was used to determine the concentrations of PCE, TCE, DCE isomers, and VC throughout the three layers of the constructed wetland. Inflow and outflow were also sampled and analyzed. In this year's data, PCE was detected at a level that was below the maximum contaminant level established by the EPA. However, it is clear that Cell 1 is still developing. This wetland cell has been in existence for three years and it is obvious that the development of a constructed wetland is a lengthy process. If a constructed wetland were to be used as a treatment process for contaminated water sources, time would have to be allowed for it to develop before it would reach maximum treatment efficiency.
Characterization Of Chlorinated Solvent Degradation In A Constructed Wetland
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Author : Nathan D. Clemmer
language : en
Publisher:
Release Date : 2003-03
Characterization Of Chlorinated Solvent Degradation In A Constructed Wetland written by Nathan D. Clemmer and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2003-03 with Constructed wetlands categories.
Widespread chlorinated ethene contamination of aquifers coupled with high costs of current treatment technologies demand innovative remediation solutions. Wetlands, maintaining anaerobic and aerobic zones promoting the complete degradation of chlorinated ethenes such as Tetrachloroethylene (PCE), could be the answer. This thesis characterized the chlorinated solvent contamination levels in three strata of an upward flow constructed wetland. Analysis of samples was accomplished by purge-and-trap gas chromatography. Water quality parameters, Dissolved Oxygen (DO), Oxidation Reduction Potential (ORP), pH, Conductivity, and Temperature, were also measured in monitoring wells with a water monitoring sonde. After removing data outliers caused by short-circuiting flow, PCE concentrations declined from an average of 32,59 +/- 0,699 ppb (+/- 95% confidence interval) in the inflow stream to an average of 0.171 +/- 0.079 ppb in the upper layer (99,3% reduction). Concentration trends of PCE degradation products cis-1,1 -Dichloroethylene (cis-DCE), Vinyl Chloride (VC), and Trichloroethylene TCE) indicate dechlorination processes are occurring. In addition to PCE, TCE at concentrations below 0,6 ppb was the only other analyte detected in the inflow and outflow, Water quality measurements (DO and 0RP) decreased from the bottom to the middle layer to a level that supports anaerobic reductive dechlorination but not methanogenesis. The DO increased slightly from the middle to the top layer while 0RP continued to decrease.
Treatment Of Chlorinated Aliphatic Contamination Of Groundwater By Horizontal Recirculation Wells And By Constructed Vertical Flow Wetlands
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Author :
language : en
Publisher:
Release Date : 2002
Treatment Of Chlorinated Aliphatic Contamination Of Groundwater By Horizontal Recirculation Wells And By Constructed Vertical Flow Wetlands written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2002 with categories.
This work explores two innovative technologies for the remediation of chlorinated ethene solvents contaminating groundwater: (1) groundwater circulation wells (GCWs) with downwell zero-valent metal reductive dechlorination reactors, and (2) constructed vertical subsurface flow wetlands. Both the natural dechlorination in wetland sediments, and the engineered dechlorination in a well using zero-valent metals have major implications for the treatment of Air Force pollutants, with the potential to save millions of dollars annually in long term remediation at hundreds of sites across the Air Force. Complementary modeling and column studies examined the potential for controlling and treating groundwater contamination using groundwater circulation wells (GCWs) with downwell zero-valent metal reductive dechlorination reactors. The construction of the field scale wetland research facility includes two complete wetland cells (140 x 60 feet each), fully contained. Chemical analysis of samples drawn from the various depths of wetland sediment suggests a very heterogeneous development of microbial activity relevant to reductive dechlorination over the course of one year of operation. Concentration contours of PCE, TCE, and nitrate suggest that reductive dechlorination is taking place when more readily reducible electron acceptors (like nitrate) are depleted. PCE is reduced ten-fold from inflow to outflow, even with significant short-circuiting of flow from the bottom sediments to the outflow. Data suggests 100-fold treatment is possible.
Treatment Of Chlorinated Aliphatic Contamination Of Groundwater By Horizontal Recirculation Wells And By Constructed Vertical Flow Wetlands
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Author : Michael L. Shelley
language : en
Publisher:
Release Date : 2002-03-01
Treatment Of Chlorinated Aliphatic Contamination Of Groundwater By Horizontal Recirculation Wells And By Constructed Vertical Flow Wetlands written by Michael L. Shelley and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2002-03-01 with categories.
This work explores two innovative technologies for the remediation of chlorinated ethene solvents contaminating groundwater: (1) groundwater circulation wells (GCWs) with downwell zero-valent metal reductive dechlorination reactors, and (2) constructed vertical subsurface flow wetlands. Both the natural dechlorination in wetland sediments, and the engineered dechlorination in a well using zero-valent metals have major implications for the treatment of Air Force pollutants, with the potential to save millions of dollars annually in long term remediation at hundreds of sites across the Air Force. Complementary modeling and column studies examined the potential for controlling and treating groundwater contamination using groundwater circulation wells (GCWs) with downwell zero-valent metal reductive dechlorination reactors. The construction of the field scale wetland research facility includes two complete wetland cells (140 x 60 feet each), fully contained. Chemical analysis of samples drawn from the various depths of wetland sediment suggests a very heterogeneous development of microbial activity relevant to reductive dechlorination over the course of one year of operation. Concentration contours of PCE, TCE, and nitrate suggest that reductive dechlorination is taking place when more readily reducible electron acceptors (like nitrate) are depleted. PCE is reduced ten-fold from inflow to outflow, even with significant short- circuiting of flow from the bottom sediments to the outflow. Data suggests 100- fold treatment is possible.
Transport And Transformations Of Chlorinated Solvent Contamination In A Saprolite And Fractured Rock Aquifer Near A Former Wastewater Treatment Plant Greenville South Carolina
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Author :
language : en
Publisher:
Release Date : 1997
Transport And Transformations Of Chlorinated Solvent Contamination In A Saprolite And Fractured Rock Aquifer Near A Former Wastewater Treatment Plant Greenville South Carolina written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1997 with Chlorohydrocarbons categories.
Removal Of Cis 1 2 Dichloroethylene From Groundwater Using A Restored Wetland
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Author : Todd Douglas DeJournett
language : en
Publisher:
Release Date : 2006
Removal Of Cis 1 2 Dichloroethylene From Groundwater Using A Restored Wetland written by Todd Douglas DeJournett and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2006 with categories.
Emerging Contaminants Vol 2
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Author : Nadia Morin-Crini
language : en
Publisher: Springer Nature
Release Date : 2021-04-28
Emerging Contaminants Vol 2 written by Nadia Morin-Crini and has been published by Springer Nature this book supported file pdf, txt, epub, kindle and other format this book has been release on 2021-04-28 with Science categories.
Emerging contaminants are chemical and biological agents for which there is growing concern about their potential health and environmental effects. The threat lies in the fact that the sources, fate and toxicology of most of these compounds have not yet been studied. Emerging contaminants, therefore, include a large number of both recently discovered and well-known compounds such as rare earth elements, viruses, bacteria, nanomaterials, microplastics, pharmaceuticals, endocrine disruptors, hormones, personal care products, cosmetics, pesticides, surfactants and industrial chemicals. Emerging contaminants have been found in many daily products, and some of them accumulate in the food chain. Correlations have been observed between aquatic pollution by emerging contaminants and discharges from wastewater treatment plants. Most actual remediation methods are not effective at removing emerging contaminants. This second volume presents comprehensive knowledge on emerging contaminants with a focus on remediation.
Characterization Of Microbial Processes That Degrade Chlorinated Solvents In A Constructed Wetland Using Organic Acid And Inorganic Anion Concentration Profiles
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Author :
language : en
Publisher:
Release Date : 2004
Characterization Of Microbial Processes That Degrade Chlorinated Solvents In A Constructed Wetland Using Organic Acid And Inorganic Anion Concentration Profiles written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2004 with categories.
Chlorinated solvents have been used in industrial cleaning and degreasing processes in the United States since the early 1900s, and their induction into the environment increased significantly with the growth of industrial processes over the past century. PCE, TCE and their daughter products have been associated with a number of human health concerns and are currently the most common contaminants found in groundwater in the United States. Wetlands possess characteristics necessary for the complete degradation of chlorinated ethenes by microorganisms via anaerobic and aerobic regions that foster the necessary oxidation-reduction conditions. Organic acid and inorganic anion concentrations were evaluated in samples taken from a constructed wetland at Wright-Patterson Air Force Base, Ohio during the summer and fall of 2003. These analyses are indicative of redox conditions in the subsurface and suggest the occurrence of microbial activities that degrade chlorinated ethenes to innocuous end products. Organic acid concentrations decreased by 100% from July 2003 to fall 2003. Combined with data collected previously during the months of December and January, this suggested that changing seasons and temperature fluctuations have a significant influence on microbial metabolisms. Nitrate and sulfate reduction above stratum C indicated mildly reducing conditions in the lowest stratum that became more highly reducing in the upper two strata. Based on the changing analyst concentrations throughout the wetland cell over several seasons, it was evident that the appropriate subsurface conditions existed for the reductive dechlorination of chlorinated ethenes.
Treatment Wetlands
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Author : Gabriela Dotro
language : en
Publisher: IWA Publishing
Release Date : 2017-11-15
Treatment Wetlands written by Gabriela Dotro and has been published by IWA Publishing this book supported file pdf, txt, epub, kindle and other format this book has been release on 2017-11-15 with Science categories.
Contents: Overview of Treatment Wetlands; Fundamentals of Treatment Wetlands; Horizontal Flow Wetlands; Vertical Flow Wetlands; French Vertical Flow Wetlands; Intensified and Modified Wetlands; Free Water Surface Wetlands; Other Applications; Additional Aspects.