The Experts below are selected from a list of 17367 Experts worldwide ranked by ideXlab platform
Jaime Nivala - One of the best experts on this subject based on the ideXlab platform.
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oxygen transfer and consumption in Subsurface Flow treatment wetlands
Ecological Engineering, 2013Co-Authors: Jaime Nivala, Scott Wallace, Tom Headley, Kinfe Kassa, Hans Brix, Manfred Van Afferden, Roland A MullerAbstract:Abstract Subsurface oxygen availability tends to be one of the main rate-limiting factors for removal of carbonaceous and nitrogenous compounds in Subsurface Flow (SSF) wetlands used for domestic wastewater treatment. This paper reviews the pertinent literature regarding oxygen transfer and consumption in Subsurface Flow treatment wetlands, and discusses the factors that influence oxygen availability. We also provide first results from a pilot-scale research facility in Langenreichenbach, Germany (15 individual systems of various designs, both with and without plants). Based on the approach given in Kadlec and Wallace (2009) , areal-based oxygen consumption rates for horizontal Flow systems were estimated to be between 0.5 and 12.9 g/m2-d; for vertical Flow systems between 7.9 and 58.6 g/m2-d; and for intensified systems between 10.9 and 87.5 g/m2-d. In general, as the level of intensification increases, so does Subsurface oxygen availability. The use of water or air pumps can result in systems with smaller area requirements (and better treatment performance), but it comes at the cost of increased electricity inputs. As the treatment wetland technology envelope expands, so must methods to compare oxygen consumption rates of traditional and intensified SSF treatment wetland designs.
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clogging in Subsurface Flow treatment wetlands measurement modeling and management
Water Research, 2012Co-Authors: Jaime Nivala, Joan García, Paul Knowles, Gabriela Dotro, Scott WallaceAbstract:This paper reviews the state of the art in measuring, modeling, and managing clogging in Subsurface-Flow treatment wetlands. Methods for measuring in situ hydraulic conductivity in treatment wetlands are now available, which provide valuable insight into assessing and evaluating the extent of clogging. These results, paired with the information from more traditional approaches (e.g., tracer testing and composition of the clog matter) are being incorporated into the latest treatment wetland models. Recent finite element analysis models can now simulate clogging development in Subsurface-Flow treatment wetlands with reasonable accuracy. Various management strategies have been developed to extend the life of clogged treatment wetlands, including gravel excavation and/or washing, chemical treatment, and application of earthworms. These strategies are compared and available cost information is reported.
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clogging in Subsurface Flow treatment wetlands occurrence and contributing factors
Ecological Engineering, 2011Co-Authors: Paul Knowles, Gabriela Dotro, Jaime Nivala, Joan GarcíaAbstract:Abstract Clogging is a major operational and maintenance issue associated with the use of Subsurface Flow wetlands for wastewater treatment, and can ultimately limit the lifetime of the system. This review considers over two decades of accumulated knowledge regarding clogging in both vertical and horizontal Subsurface Flow treatment wetlands. The various physical, chemical and biological factors responsible for clogging are identified and discussed. The occurrence of clogging is placed into the context of various design and operational parameters such as wastewater characteristics, upstream treatment processes, intermittent or continuous operation, influent distribution, and media type. This information is then used to describe how clogging develops within, and subsequently impacts, common variants of Subsurface Flow treatment wetland typically used in the U.S., U.K., France and Germany. Comparison of these systems emphasized that both hydraulic loading rate and solids loading rate need to be considered when designing systems to operate robustly, i.e. hydraulic overloading makes horizontal-Flow tertiary treatment systems in the U.K. more susceptible to clogging problems than vertical-Flow primary treatment systems in France. Future research should focus on elucidating the underlying mechanisms of clogging as they relate to the design, operation, and maintenance of Subsurface Flow treatment wetlands.
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Treatment of Landfill Leachate in Aerated Subsurface Flow Wetlands: Two Case Studies
Water and Nutrient Management in Natural and Constructed Wetlands, 2010Co-Authors: Jaime Nivala, Scott WallaceAbstract:Treatment of landfill leachate is challenging due to high concentrations of oxygen-demanding compounds, such as biochemical oxygen demand (BOD) and ammonia nitrogen. The limited oxygen-transfer capability of conventional Subsurface Flow treatment wetlands has lead to the development of alternative design configurations that improve Subsurface oxygen availability. This chapter compares the treatment performance of two aerated Subsurface Flow constructed wetlands treating landfill leachate against other, non-aerated systems. Results from these pilot studies indicate that aerated Subsurface Flow treatment wetlands are a viable technology selection for removal of ammonia-nitrogen of landfill leachate.
Joan García - One of the best experts on this subject based on the ideXlab platform.
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clogging in Subsurface Flow treatment wetlands measurement modeling and management
Water Research, 2012Co-Authors: Jaime Nivala, Joan García, Paul Knowles, Gabriela Dotro, Scott WallaceAbstract:This paper reviews the state of the art in measuring, modeling, and managing clogging in Subsurface-Flow treatment wetlands. Methods for measuring in situ hydraulic conductivity in treatment wetlands are now available, which provide valuable insight into assessing and evaluating the extent of clogging. These results, paired with the information from more traditional approaches (e.g., tracer testing and composition of the clog matter) are being incorporated into the latest treatment wetland models. Recent finite element analysis models can now simulate clogging development in Subsurface-Flow treatment wetlands with reasonable accuracy. Various management strategies have been developed to extend the life of clogged treatment wetlands, including gravel excavation and/or washing, chemical treatment, and application of earthworms. These strategies are compared and available cost information is reported.
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clogging in Subsurface Flow treatment wetlands occurrence and contributing factors
Ecological Engineering, 2011Co-Authors: Paul Knowles, Gabriela Dotro, Jaime Nivala, Joan GarcíaAbstract:Abstract Clogging is a major operational and maintenance issue associated with the use of Subsurface Flow wetlands for wastewater treatment, and can ultimately limit the lifetime of the system. This review considers over two decades of accumulated knowledge regarding clogging in both vertical and horizontal Subsurface Flow treatment wetlands. The various physical, chemical and biological factors responsible for clogging are identified and discussed. The occurrence of clogging is placed into the context of various design and operational parameters such as wastewater characteristics, upstream treatment processes, intermittent or continuous operation, influent distribution, and media type. This information is then used to describe how clogging develops within, and subsequently impacts, common variants of Subsurface Flow treatment wetland typically used in the U.S., U.K., France and Germany. Comparison of these systems emphasized that both hydraulic loading rate and solids loading rate need to be considered when designing systems to operate robustly, i.e. hydraulic overloading makes horizontal-Flow tertiary treatment systems in the U.K. more susceptible to clogging problems than vertical-Flow primary treatment systems in France. Future research should focus on elucidating the underlying mechanisms of clogging as they relate to the design, operation, and maintenance of Subsurface Flow treatment wetlands.
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Contaminant removal processes in Subsurface-Flow constructed wetlands: A review
Critical Reviews in Environmental Science and Technology, 2010Co-Authors: Joan García, Emmanuel Lesage, Víctor Matamoros, Jordi Morató, Diederik P. L. Rousseau, Josep M. BayonaAbstract:The main contaminant removal processes occurring in Subsurface-Flow\nconstructed wetlands treating wastewater are reviewed. Redox conditions\nprevailing in the wetlands are analyzed and linked to contaminant\nremoval mechanisms. The removal of organic matter and its accumulation\nin the granular medium of the wetlands are evaluated with regard to\nparticulate and dissolved components and clogging processes. The main\nbiological processes linked to organic matter transformationaerobic\nrespiration, denitrification, acid fermentation, sulfate reduction, and\nmethanogenesisare reviewed separately. The processes of removal of\nsurfactants, pesticides and herbicides, emergent contaminants,\nnutrients, heavy metals and faecal organisms are analyzed. Advances in\nwetland modeling are presented as a powerful tool for understanding\nmultiple interactions occurring in Subsurface-Flow constructed wetlands\nduring the removal of contaminants.
Scott Wallace - One of the best experts on this subject based on the ideXlab platform.
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oxygen transfer and consumption in Subsurface Flow treatment wetlands
Ecological Engineering, 2013Co-Authors: Jaime Nivala, Scott Wallace, Tom Headley, Kinfe Kassa, Hans Brix, Manfred Van Afferden, Roland A MullerAbstract:Abstract Subsurface oxygen availability tends to be one of the main rate-limiting factors for removal of carbonaceous and nitrogenous compounds in Subsurface Flow (SSF) wetlands used for domestic wastewater treatment. This paper reviews the pertinent literature regarding oxygen transfer and consumption in Subsurface Flow treatment wetlands, and discusses the factors that influence oxygen availability. We also provide first results from a pilot-scale research facility in Langenreichenbach, Germany (15 individual systems of various designs, both with and without plants). Based on the approach given in Kadlec and Wallace (2009) , areal-based oxygen consumption rates for horizontal Flow systems were estimated to be between 0.5 and 12.9 g/m2-d; for vertical Flow systems between 7.9 and 58.6 g/m2-d; and for intensified systems between 10.9 and 87.5 g/m2-d. In general, as the level of intensification increases, so does Subsurface oxygen availability. The use of water or air pumps can result in systems with smaller area requirements (and better treatment performance), but it comes at the cost of increased electricity inputs. As the treatment wetland technology envelope expands, so must methods to compare oxygen consumption rates of traditional and intensified SSF treatment wetland designs.
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clogging in Subsurface Flow treatment wetlands measurement modeling and management
Water Research, 2012Co-Authors: Jaime Nivala, Joan García, Paul Knowles, Gabriela Dotro, Scott WallaceAbstract:This paper reviews the state of the art in measuring, modeling, and managing clogging in Subsurface-Flow treatment wetlands. Methods for measuring in situ hydraulic conductivity in treatment wetlands are now available, which provide valuable insight into assessing and evaluating the extent of clogging. These results, paired with the information from more traditional approaches (e.g., tracer testing and composition of the clog matter) are being incorporated into the latest treatment wetland models. Recent finite element analysis models can now simulate clogging development in Subsurface-Flow treatment wetlands with reasonable accuracy. Various management strategies have been developed to extend the life of clogged treatment wetlands, including gravel excavation and/or washing, chemical treatment, and application of earthworms. These strategies are compared and available cost information is reported.
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Treatment of Landfill Leachate in Aerated Subsurface Flow Wetlands: Two Case Studies
Water and Nutrient Management in Natural and Constructed Wetlands, 2010Co-Authors: Jaime Nivala, Scott WallaceAbstract:Treatment of landfill leachate is challenging due to high concentrations of oxygen-demanding compounds, such as biochemical oxygen demand (BOD) and ammonia nitrogen. The limited oxygen-transfer capability of conventional Subsurface Flow treatment wetlands has lead to the development of alternative design configurations that improve Subsurface oxygen availability. This chapter compares the treatment performance of two aerated Subsurface Flow constructed wetlands treating landfill leachate against other, non-aerated systems. Results from these pilot studies indicate that aerated Subsurface Flow treatment wetlands are a viable technology selection for removal of ammonia-nitrogen of landfill leachate.
Gabriela Dotro - One of the best experts on this subject based on the ideXlab platform.
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clogging in Subsurface Flow treatment wetlands measurement modeling and management
Water Research, 2012Co-Authors: Jaime Nivala, Joan García, Paul Knowles, Gabriela Dotro, Scott WallaceAbstract:This paper reviews the state of the art in measuring, modeling, and managing clogging in Subsurface-Flow treatment wetlands. Methods for measuring in situ hydraulic conductivity in treatment wetlands are now available, which provide valuable insight into assessing and evaluating the extent of clogging. These results, paired with the information from more traditional approaches (e.g., tracer testing and composition of the clog matter) are being incorporated into the latest treatment wetland models. Recent finite element analysis models can now simulate clogging development in Subsurface-Flow treatment wetlands with reasonable accuracy. Various management strategies have been developed to extend the life of clogged treatment wetlands, including gravel excavation and/or washing, chemical treatment, and application of earthworms. These strategies are compared and available cost information is reported.
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clogging in Subsurface Flow treatment wetlands occurrence and contributing factors
Ecological Engineering, 2011Co-Authors: Paul Knowles, Gabriela Dotro, Jaime Nivala, Joan GarcíaAbstract:Abstract Clogging is a major operational and maintenance issue associated with the use of Subsurface Flow wetlands for wastewater treatment, and can ultimately limit the lifetime of the system. This review considers over two decades of accumulated knowledge regarding clogging in both vertical and horizontal Subsurface Flow treatment wetlands. The various physical, chemical and biological factors responsible for clogging are identified and discussed. The occurrence of clogging is placed into the context of various design and operational parameters such as wastewater characteristics, upstream treatment processes, intermittent or continuous operation, influent distribution, and media type. This information is then used to describe how clogging develops within, and subsequently impacts, common variants of Subsurface Flow treatment wetland typically used in the U.S., U.K., France and Germany. Comparison of these systems emphasized that both hydraulic loading rate and solids loading rate need to be considered when designing systems to operate robustly, i.e. hydraulic overloading makes horizontal-Flow tertiary treatment systems in the U.K. more susceptible to clogging problems than vertical-Flow primary treatment systems in France. Future research should focus on elucidating the underlying mechanisms of clogging as they relate to the design, operation, and maintenance of Subsurface Flow treatment wetlands.
Paul Knowles - One of the best experts on this subject based on the ideXlab platform.
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clogging in Subsurface Flow treatment wetlands measurement modeling and management
Water Research, 2012Co-Authors: Jaime Nivala, Joan García, Paul Knowles, Gabriela Dotro, Scott WallaceAbstract:This paper reviews the state of the art in measuring, modeling, and managing clogging in Subsurface-Flow treatment wetlands. Methods for measuring in situ hydraulic conductivity in treatment wetlands are now available, which provide valuable insight into assessing and evaluating the extent of clogging. These results, paired with the information from more traditional approaches (e.g., tracer testing and composition of the clog matter) are being incorporated into the latest treatment wetland models. Recent finite element analysis models can now simulate clogging development in Subsurface-Flow treatment wetlands with reasonable accuracy. Various management strategies have been developed to extend the life of clogged treatment wetlands, including gravel excavation and/or washing, chemical treatment, and application of earthworms. These strategies are compared and available cost information is reported.
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clogging in Subsurface Flow treatment wetlands occurrence and contributing factors
Ecological Engineering, 2011Co-Authors: Paul Knowles, Gabriela Dotro, Jaime Nivala, Joan GarcíaAbstract:Abstract Clogging is a major operational and maintenance issue associated with the use of Subsurface Flow wetlands for wastewater treatment, and can ultimately limit the lifetime of the system. This review considers over two decades of accumulated knowledge regarding clogging in both vertical and horizontal Subsurface Flow treatment wetlands. The various physical, chemical and biological factors responsible for clogging are identified and discussed. The occurrence of clogging is placed into the context of various design and operational parameters such as wastewater characteristics, upstream treatment processes, intermittent or continuous operation, influent distribution, and media type. This information is then used to describe how clogging develops within, and subsequently impacts, common variants of Subsurface Flow treatment wetland typically used in the U.S., U.K., France and Germany. Comparison of these systems emphasized that both hydraulic loading rate and solids loading rate need to be considered when designing systems to operate robustly, i.e. hydraulic overloading makes horizontal-Flow tertiary treatment systems in the U.K. more susceptible to clogging problems than vertical-Flow primary treatment systems in France. Future research should focus on elucidating the underlying mechanisms of clogging as they relate to the design, operation, and maintenance of Subsurface Flow treatment wetlands.
