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Rémy Gourdon - One of the best experts on this subject based on the ideXlab platform.
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Comparative characterization of surface Sludge deposits from fourteen French Vertical Flow Constructed Wetlands sewage treatment plants using biological, chemical and thermal indices
Science of the Total Environment, 2019Co-Authors: M. Kania, Mathieu Gautier, Philippe Michel, Anne Imig, Rémy GourdonAbstract:Due to their design and mode of operation, French Vertical Flow Constructed Wetlands (VFCWs) accumulate suspended solids from the inflow wastewater in the form of a Sludge Layer at the surface of the first filter. In order to maintain the treatment performance over the long term, the characteristics of the Sludge deposits and their evolution have to be well described. In this objective, a panel of Sludge deposit samples taken from 14 French VFCW sewage treatment plants was investigated. Elemental composition and organic matter content, nature and reactivity were analyzed. Results clearly revealed two categories of Sludge deposits, namely the “young-age plants” type (1 year of operation and less) and the “mature plants” type (3 years of operation and more). Sludge deposits from the “mature plants” exhibited same biological, physical and chemical properties. Their organic matter was globally less abundant, more humified and less biodegradable than in the young-age plants type. Their overall contents in trace metals were also higher, although in a limited manner. The effect of additional treatments, particularly FeCl3 injection for phosphorus precipitation, was observable in the “young-age plants” group. Finally, the Sludge deposits sampled from one particular plant with specific operating conditions were found to exhibit very different characteristics from those of either groups identified. This observation underlined the influence of local conditions on the typology of the Sludge deposits.
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Analytical indicators to characterize Particulate Organic Matter (POM) and its evolution in French Vertical Flow Constructed Wetlands (VFCWs)
The Science of the total environment, 2017Co-Authors: Manon Kania, Mathieu Gautier, Philippe Michel, Erik Bonjour, Régis Guégan, Patrick Jame, Jianguo Liu, Rémy GourdonAbstract:The design of French VFCWs leads to the formation of a Sludge Layer at the surface of the first filters due to the retention of suspended solids from the percolation of unsettled wastewater. This Layer plays a major role in the system but still little is known on its characteristics and evolutions. In this study, suspended solids and Sludge deposits sampled from two French VFCW plants were analyzed by different methods in the objective to assess the evolution of particulate organic matter (POM) along the treatment chain and within the Sludge Layer, and identify relevant analytical indicators of these phenomena. The treatment chain included an aerobic trickling filter followed by FeCl3 injection and two successive stages of filters. Thermal analyses showed that OM contents of suspended solids decreased along the treatment chain. POM in inflow suspended solids was predominantly composed of reactive, biodegradable compounds which were partly hydrolyzed and mineralized notably at the trickling filter stage. 3D fluorescence spectra collected from aqueous POM extracts confirmed the evolution of organic matter from low-molecular reactive compounds to more complex and stable structures such as humic-like substances. FTIR confirmed the mineralization of POM's reactive constituents along the treatment chain by the decrease in the intensities of the characteristics bands of aliphatic compounds or proteins, and its humification in the Sludge deposits through the relative increase of the bands at 1634 cm− 1 (vC = O) and 1238 cm− 1 (δC = O and/or δOH). Isotopic ratios δ2H/1H and δ15N/14N were found to be good indicators of POM evolutions. The higher values of δ2H/1H and δ15N/14N ratios measured in Sludge deposits as compared to inflow suspended solids were related to POM humification and to microbial processes of POM hydrolysis and mineralization, respectively.
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Influence du pH sur la libération du phosphore accumulé dans les boues de surface d'un filtre planté de roseaux recevant des eaux usées traitées avec du FeCl3
Déchets Sciences et Techniques, 2013Co-Authors: Boram Kim, Mathieu Gautier, Alexandre Buet, Philippe Michel, Rémy GourdonAbstract:Constructed wetlands (CW) provide good removal of organic matter and nitrogen, but their performance for phosphorus removal are the subject of debate. However, phosphorus is a factor in eutrophication of surface waters, and it is therefore necessary to limit discharges into the natural environment. In order to improve denitrification and phosphorus removal as compared to classical vertical flow constructed wetlands (VFCWs), the French company SCIRPE has developed a process called Azoé® patented in 2007. The process includes a pre-treatment on a biological trickling filter to partly degrade the organic load, followed by two vertical stages of partially saturated constructed wetlands for the removal of nitrogen by nitrification and denitrification. The reduction of phosphorus in the Azoé® system is achieved through the addition of FeCl3 as a coagulant, followed by filtration through the VFCWs. Phosphorus thus precipitated is thereby accumulated in the form of a Sludge Layer mostly at the surface of the 1st filter. Over time, the Sludge Layer progressively grows and may eventually release part of the accumulated phosphorus depending on the biophysicochemical conditions (Kim et al., 2013). The objective of this study was to determine the influence of pH on the solubilization of phosphorus from Sludge material sampled from a plant in operation. Results showed that the buffering capacity of the Sludge allowed to stabilize pH when in contact with moderately acidic (pH 4) or alkaline (pH 10) solutions. Under more drastic conditions, changes of pH were observed, but the release of phosphorus remained fairly low.
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Influence du pH sur la libération du phosphore accumulé dans les boues de surface d'un filtre planté de roseaux recevant des eaux usées traitées avec du FeCl3
Déchets sciences et techniques, 2013Co-Authors: Boram Kim, Mathieu Gautier, Alexandre Buet, Philippe Michel, Rémy GourdonAbstract:Constructed wetlands (CW) provide good removal of organic matter and nitrogen, but their performance for phosphorus removal are the subject of debate. However, phosphorus is a factor in eutrophication of surface waters, and it is therefore necessary to limit discharges into the natural environment. In order to improve denitrification and phosphorus removal as compared to classical vertical flow constructed wetlands (VFCWs), the French company SCIRPE has developed a process called Azoe® patented in 2007. The process includes a pre-treatment on a biological trickling filter to partly degrade the organic load, followed by two vertical stages of partially saturated constructed wetlands for the removal of nitrogen by nitrification and denitrification. The reduction of phosphorus in the Azoe® system is achieved through the addition of FeCl3 as a coagulant, followed by filtration through the VFCWs. Phosphorus thus precipitated is thereby accumulated in the form of a Sludge Layer mostly at the surface of the 1st filter. Over time, the Sludge Layer progressively grows and may eventually release part of the accumulated phosphorus depending on the biophysicochemical conditions (Kim et al., 2013). The objective of this study was to determine the influence of pH on the solubilization of phosphorus from Sludge material sampled from a plant in operation. Results showed that the buffering capacity of the Sludge allowed to stabilize pH when in contact with moderately acidic (pH 4) or alkaline (pH 10) solutions. Under more drastic conditions, changes of pH were observed, but the release of phosphorus remained fairly low.
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Physical–chemical characterization of Sludge and granular materials from a vertical flow constructed wetland for municipal wastewater treatment
Water Science and Technology, 2013Co-Authors: Boram Kim, Mathieu Gautier, Philippe Michel, Rémy GourdonAbstract:The use of Vertical Flow Constructed Wetlands (VFCW) is well developed in France and other countries for the treatment of wastewaters from small communities. The patented Azoé® process has been developed by a French company SCIRPE in order to improve denitrification and phosphorus removal as compared to classical VFCWs. It includes a biological trickling filter pretreatment followed by two stages of partially flooded VFCW (pf-VFCW). The performances of partially flooded VFCW are well demonstrated for the removal of organic matter and nitrogen. The system is now being considered for phosphorus removal as well. In this article, Sludge and granular materials sampled from the filters of a municipal plant where Azoé® system has been operated for 8 years were analyzed in order to provide data that may contribute to better understand the dynamics of phosphorus retention. Elemental analyses showed that phosphorus was predominantly captured in the Sludge Layer accumulated at the surface of the first stage. The progressive mineralization of the Sludge over time was also clearly highlighted. The phosphate phases were mainly associated with iron and calcium. The transport of phosphorus via the migration of fine particles through the porous medium in the first stage was also observed.
Thomas F. Ducey - One of the best experts on this subject based on the ideXlab platform.
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denitrification of nitrified and non nitrified swine lagoon wastewater in the suspended Sludge Layer of treatment wetlands
Ecological Engineering, 2009Co-Authors: Patrick G. Hunt, Kenneth C. Stone, T. A. Matheny, M. E. Poach, Matias B. Vanotti, Thomas F. DuceyAbstract:One method for managing livestock-wastewater N is the use of treatment wetlands. The objectives of this study were to (1) assess the magnitude of denitrification enzyme activity (DEA) in the suspended Sludge Layers of bulrush and cattail treatment wetlands, and (2) evaluate the impact of nitrogen pretreatment on DEA in the suspended Sludge Layer. The study used four wetland cells (3.6 m × 33.5 m) with two cells connected in series. Each wetland series received either untreated or partially nitrified swine wastewater from a single-cell anaerobic lagoon. The DEA of the suspended Sludge Layers of the constructed wetlands was measured by the acetylene inhibition method. The control DEA treatment for the Sludge Layer had a mean rate of 18 gN 2O-N g−1 Sludge h−1. Moreover, the potential DEA (nitrate-N and glucose-C added) mean was very large, 121 gN 2O-N g −1 Sludge h −1 . These DEA rates are consistent with the previously reported high levels of nitrogen removal by denitrification from these wetlands, especially when the wastewater was partially nitrified. Stepwise regression using distance within the wetland, wastewater nitrate, and wastewater ammonia explained much of the variation in DEA rates. In both bulrush and cattail wetlands, there were zones of very high potential DEA. Published by Elsevier B.V.
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Denitrification of nitrified and non-nitrified swine lagoon wastewater in the suspended Sludge Layer of treatment wetlands ☆
Ecological Engineering, 2009Co-Authors: Patrick G. Hunt, Kenneth C. Stone, T. A. Matheny, M. E. Poach, Matias B. Vanotti, Thomas F. DuceyAbstract:One method for managing livestock-wastewater N is the use of treatment wetlands. The objectives of this study were to (1) assess the magnitude of denitrification enzyme activity (DEA) in the suspended Sludge Layers of bulrush and cattail treatment wetlands, and (2) evaluate the impact of nitrogen pretreatment on DEA in the suspended Sludge Layer. The study used four wetland cells (3.6 m × 33.5 m) with two cells connected in series. Each wetland series received either untreated or partially nitrified swine wastewater from a single-cell anaerobic lagoon. The DEA of the suspended Sludge Layers of the constructed wetlands was measured by the acetylene inhibition method. The control DEA treatment for the Sludge Layer had a mean rate of 18 gN 2O-N g−1 Sludge h−1. Moreover, the potential DEA (nitrate-N and glucose-C added) mean was very large, 121 gN 2O-N g −1 Sludge h −1 . These DEA rates are consistent with the previously reported high levels of nitrogen removal by denitrification from these wetlands, especially when the wastewater was partially nitrified. Stepwise regression using distance within the wetland, wastewater nitrate, and wastewater ammonia explained much of the variation in DEA rates. In both bulrush and cattail wetlands, there were zones of very high potential DEA. Published by Elsevier B.V.
Mathieu Gautier - One of the best experts on this subject based on the ideXlab platform.
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Comparative characterization of surface Sludge deposits from fourteen French Vertical Flow Constructed Wetlands sewage treatment plants using biological, chemical and thermal indices
Science of the Total Environment, 2019Co-Authors: M. Kania, Mathieu Gautier, Philippe Michel, Anne Imig, Rémy GourdonAbstract:Due to their design and mode of operation, French Vertical Flow Constructed Wetlands (VFCWs) accumulate suspended solids from the inflow wastewater in the form of a Sludge Layer at the surface of the first filter. In order to maintain the treatment performance over the long term, the characteristics of the Sludge deposits and their evolution have to be well described. In this objective, a panel of Sludge deposit samples taken from 14 French VFCW sewage treatment plants was investigated. Elemental composition and organic matter content, nature and reactivity were analyzed. Results clearly revealed two categories of Sludge deposits, namely the “young-age plants” type (1 year of operation and less) and the “mature plants” type (3 years of operation and more). Sludge deposits from the “mature plants” exhibited same biological, physical and chemical properties. Their organic matter was globally less abundant, more humified and less biodegradable than in the young-age plants type. Their overall contents in trace metals were also higher, although in a limited manner. The effect of additional treatments, particularly FeCl3 injection for phosphorus precipitation, was observable in the “young-age plants” group. Finally, the Sludge deposits sampled from one particular plant with specific operating conditions were found to exhibit very different characteristics from those of either groups identified. This observation underlined the influence of local conditions on the typology of the Sludge deposits.
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Study of aggregation in surface Sludge deposits from 14 full-scale French constructed wetlands using particle size distribution and dynamic vapor sorption analyses
Water Science and Technology, 2018Co-Authors: M. Kania, Mathieu Gautier, Philippe Michel, R. GourdonAbstract:French vertical flow constructed wetlands (French VFCWs) are widely used for the treatment of wastewaters from small communities. In the system, unsettled wastewater is percolated through two successive stages of filter-cells planted with reeds. This causes the formation of a surface Sludge Layer. This Layer plays positive roles in the treatment performance, but also leads to clogging. The objective of this study was to contribute to the description of the Sludge deposits characteristics and their dynamics of evolution, which may control the development of clogging. Representative samples of Sludge deposits were taken from 14 French VFCWs full-scale plants and analyzed for particle size, dynamic vapor sorption and other parameters of composition to compare their structure and evaluate the factors of influence. Results showed that ageing of the surface deposits Layer over the years of operation in each plant induced the formation and integration of microaggregates within the initial macrostructure of fresh organic matter (OM). The humification process of the OM was found to play a key role in the aggregation process. The injection of FeCl3 operated to precipitate phosphates before filtration was found to accelerate the aggregation process in the early phase (
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Analytical indicators to characterize Particulate Organic Matter (POM) and its evolution in French Vertical Flow Constructed Wetlands (VFCWs)
The Science of the total environment, 2017Co-Authors: Manon Kania, Mathieu Gautier, Philippe Michel, Erik Bonjour, Régis Guégan, Patrick Jame, Jianguo Liu, Rémy GourdonAbstract:The design of French VFCWs leads to the formation of a Sludge Layer at the surface of the first filters due to the retention of suspended solids from the percolation of unsettled wastewater. This Layer plays a major role in the system but still little is known on its characteristics and evolutions. In this study, suspended solids and Sludge deposits sampled from two French VFCW plants were analyzed by different methods in the objective to assess the evolution of particulate organic matter (POM) along the treatment chain and within the Sludge Layer, and identify relevant analytical indicators of these phenomena. The treatment chain included an aerobic trickling filter followed by FeCl3 injection and two successive stages of filters. Thermal analyses showed that OM contents of suspended solids decreased along the treatment chain. POM in inflow suspended solids was predominantly composed of reactive, biodegradable compounds which were partly hydrolyzed and mineralized notably at the trickling filter stage. 3D fluorescence spectra collected from aqueous POM extracts confirmed the evolution of organic matter from low-molecular reactive compounds to more complex and stable structures such as humic-like substances. FTIR confirmed the mineralization of POM's reactive constituents along the treatment chain by the decrease in the intensities of the characteristics bands of aliphatic compounds or proteins, and its humification in the Sludge deposits through the relative increase of the bands at 1634 cm− 1 (vC = O) and 1238 cm− 1 (δC = O and/or δOH). Isotopic ratios δ2H/1H and δ15N/14N were found to be good indicators of POM evolutions. The higher values of δ2H/1H and δ15N/14N ratios measured in Sludge deposits as compared to inflow suspended solids were related to POM humification and to microbial processes of POM hydrolysis and mineralization, respectively.
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Influence du pH sur la libération du phosphore accumulé dans les boues de surface d'un filtre planté de roseaux recevant des eaux usées traitées avec du FeCl3
Déchets Sciences et Techniques, 2013Co-Authors: Boram Kim, Mathieu Gautier, Alexandre Buet, Philippe Michel, Rémy GourdonAbstract:Constructed wetlands (CW) provide good removal of organic matter and nitrogen, but their performance for phosphorus removal are the subject of debate. However, phosphorus is a factor in eutrophication of surface waters, and it is therefore necessary to limit discharges into the natural environment. In order to improve denitrification and phosphorus removal as compared to classical vertical flow constructed wetlands (VFCWs), the French company SCIRPE has developed a process called Azoé® patented in 2007. The process includes a pre-treatment on a biological trickling filter to partly degrade the organic load, followed by two vertical stages of partially saturated constructed wetlands for the removal of nitrogen by nitrification and denitrification. The reduction of phosphorus in the Azoé® system is achieved through the addition of FeCl3 as a coagulant, followed by filtration through the VFCWs. Phosphorus thus precipitated is thereby accumulated in the form of a Sludge Layer mostly at the surface of the 1st filter. Over time, the Sludge Layer progressively grows and may eventually release part of the accumulated phosphorus depending on the biophysicochemical conditions (Kim et al., 2013). The objective of this study was to determine the influence of pH on the solubilization of phosphorus from Sludge material sampled from a plant in operation. Results showed that the buffering capacity of the Sludge allowed to stabilize pH when in contact with moderately acidic (pH 4) or alkaline (pH 10) solutions. Under more drastic conditions, changes of pH were observed, but the release of phosphorus remained fairly low.
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Influence du pH sur la libération du phosphore accumulé dans les boues de surface d'un filtre planté de roseaux recevant des eaux usées traitées avec du FeCl3
Déchets sciences et techniques, 2013Co-Authors: Boram Kim, Mathieu Gautier, Alexandre Buet, Philippe Michel, Rémy GourdonAbstract:Constructed wetlands (CW) provide good removal of organic matter and nitrogen, but their performance for phosphorus removal are the subject of debate. However, phosphorus is a factor in eutrophication of surface waters, and it is therefore necessary to limit discharges into the natural environment. In order to improve denitrification and phosphorus removal as compared to classical vertical flow constructed wetlands (VFCWs), the French company SCIRPE has developed a process called Azoe® patented in 2007. The process includes a pre-treatment on a biological trickling filter to partly degrade the organic load, followed by two vertical stages of partially saturated constructed wetlands for the removal of nitrogen by nitrification and denitrification. The reduction of phosphorus in the Azoe® system is achieved through the addition of FeCl3 as a coagulant, followed by filtration through the VFCWs. Phosphorus thus precipitated is thereby accumulated in the form of a Sludge Layer mostly at the surface of the 1st filter. Over time, the Sludge Layer progressively grows and may eventually release part of the accumulated phosphorus depending on the biophysicochemical conditions (Kim et al., 2013). The objective of this study was to determine the influence of pH on the solubilization of phosphorus from Sludge material sampled from a plant in operation. Results showed that the buffering capacity of the Sludge allowed to stabilize pH when in contact with moderately acidic (pH 4) or alkaline (pH 10) solutions. Under more drastic conditions, changes of pH were observed, but the release of phosphorus remained fairly low.
Philippe Michel - One of the best experts on this subject based on the ideXlab platform.
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Comparative characterization of surface Sludge deposits from fourteen French Vertical Flow Constructed Wetlands sewage treatment plants using biological, chemical and thermal indices
Science of the Total Environment, 2019Co-Authors: M. Kania, Mathieu Gautier, Philippe Michel, Anne Imig, Rémy GourdonAbstract:Due to their design and mode of operation, French Vertical Flow Constructed Wetlands (VFCWs) accumulate suspended solids from the inflow wastewater in the form of a Sludge Layer at the surface of the first filter. In order to maintain the treatment performance over the long term, the characteristics of the Sludge deposits and their evolution have to be well described. In this objective, a panel of Sludge deposit samples taken from 14 French VFCW sewage treatment plants was investigated. Elemental composition and organic matter content, nature and reactivity were analyzed. Results clearly revealed two categories of Sludge deposits, namely the “young-age plants” type (1 year of operation and less) and the “mature plants” type (3 years of operation and more). Sludge deposits from the “mature plants” exhibited same biological, physical and chemical properties. Their organic matter was globally less abundant, more humified and less biodegradable than in the young-age plants type. Their overall contents in trace metals were also higher, although in a limited manner. The effect of additional treatments, particularly FeCl3 injection for phosphorus precipitation, was observable in the “young-age plants” group. Finally, the Sludge deposits sampled from one particular plant with specific operating conditions were found to exhibit very different characteristics from those of either groups identified. This observation underlined the influence of local conditions on the typology of the Sludge deposits.
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Study of aggregation in surface Sludge deposits from 14 full-scale French constructed wetlands using particle size distribution and dynamic vapor sorption analyses
Water Science and Technology, 2018Co-Authors: M. Kania, Mathieu Gautier, Philippe Michel, R. GourdonAbstract:French vertical flow constructed wetlands (French VFCWs) are widely used for the treatment of wastewaters from small communities. In the system, unsettled wastewater is percolated through two successive stages of filter-cells planted with reeds. This causes the formation of a surface Sludge Layer. This Layer plays positive roles in the treatment performance, but also leads to clogging. The objective of this study was to contribute to the description of the Sludge deposits characteristics and their dynamics of evolution, which may control the development of clogging. Representative samples of Sludge deposits were taken from 14 French VFCWs full-scale plants and analyzed for particle size, dynamic vapor sorption and other parameters of composition to compare their structure and evaluate the factors of influence. Results showed that ageing of the surface deposits Layer over the years of operation in each plant induced the formation and integration of microaggregates within the initial macrostructure of fresh organic matter (OM). The humification process of the OM was found to play a key role in the aggregation process. The injection of FeCl3 operated to precipitate phosphates before filtration was found to accelerate the aggregation process in the early phase (
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Analytical indicators to characterize Particulate Organic Matter (POM) and its evolution in French Vertical Flow Constructed Wetlands (VFCWs)
The Science of the total environment, 2017Co-Authors: Manon Kania, Mathieu Gautier, Philippe Michel, Erik Bonjour, Régis Guégan, Patrick Jame, Jianguo Liu, Rémy GourdonAbstract:The design of French VFCWs leads to the formation of a Sludge Layer at the surface of the first filters due to the retention of suspended solids from the percolation of unsettled wastewater. This Layer plays a major role in the system but still little is known on its characteristics and evolutions. In this study, suspended solids and Sludge deposits sampled from two French VFCW plants were analyzed by different methods in the objective to assess the evolution of particulate organic matter (POM) along the treatment chain and within the Sludge Layer, and identify relevant analytical indicators of these phenomena. The treatment chain included an aerobic trickling filter followed by FeCl3 injection and two successive stages of filters. Thermal analyses showed that OM contents of suspended solids decreased along the treatment chain. POM in inflow suspended solids was predominantly composed of reactive, biodegradable compounds which were partly hydrolyzed and mineralized notably at the trickling filter stage. 3D fluorescence spectra collected from aqueous POM extracts confirmed the evolution of organic matter from low-molecular reactive compounds to more complex and stable structures such as humic-like substances. FTIR confirmed the mineralization of POM's reactive constituents along the treatment chain by the decrease in the intensities of the characteristics bands of aliphatic compounds or proteins, and its humification in the Sludge deposits through the relative increase of the bands at 1634 cm− 1 (vC = O) and 1238 cm− 1 (δC = O and/or δOH). Isotopic ratios δ2H/1H and δ15N/14N were found to be good indicators of POM evolutions. The higher values of δ2H/1H and δ15N/14N ratios measured in Sludge deposits as compared to inflow suspended solids were related to POM humification and to microbial processes of POM hydrolysis and mineralization, respectively.
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Influence du pH sur la libération du phosphore accumulé dans les boues de surface d'un filtre planté de roseaux recevant des eaux usées traitées avec du FeCl3
Déchets Sciences et Techniques, 2013Co-Authors: Boram Kim, Mathieu Gautier, Alexandre Buet, Philippe Michel, Rémy GourdonAbstract:Constructed wetlands (CW) provide good removal of organic matter and nitrogen, but their performance for phosphorus removal are the subject of debate. However, phosphorus is a factor in eutrophication of surface waters, and it is therefore necessary to limit discharges into the natural environment. In order to improve denitrification and phosphorus removal as compared to classical vertical flow constructed wetlands (VFCWs), the French company SCIRPE has developed a process called Azoé® patented in 2007. The process includes a pre-treatment on a biological trickling filter to partly degrade the organic load, followed by two vertical stages of partially saturated constructed wetlands for the removal of nitrogen by nitrification and denitrification. The reduction of phosphorus in the Azoé® system is achieved through the addition of FeCl3 as a coagulant, followed by filtration through the VFCWs. Phosphorus thus precipitated is thereby accumulated in the form of a Sludge Layer mostly at the surface of the 1st filter. Over time, the Sludge Layer progressively grows and may eventually release part of the accumulated phosphorus depending on the biophysicochemical conditions (Kim et al., 2013). The objective of this study was to determine the influence of pH on the solubilization of phosphorus from Sludge material sampled from a plant in operation. Results showed that the buffering capacity of the Sludge allowed to stabilize pH when in contact with moderately acidic (pH 4) or alkaline (pH 10) solutions. Under more drastic conditions, changes of pH were observed, but the release of phosphorus remained fairly low.
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Influence du pH sur la libération du phosphore accumulé dans les boues de surface d'un filtre planté de roseaux recevant des eaux usées traitées avec du FeCl3
Déchets sciences et techniques, 2013Co-Authors: Boram Kim, Mathieu Gautier, Alexandre Buet, Philippe Michel, Rémy GourdonAbstract:Constructed wetlands (CW) provide good removal of organic matter and nitrogen, but their performance for phosphorus removal are the subject of debate. However, phosphorus is a factor in eutrophication of surface waters, and it is therefore necessary to limit discharges into the natural environment. In order to improve denitrification and phosphorus removal as compared to classical vertical flow constructed wetlands (VFCWs), the French company SCIRPE has developed a process called Azoe® patented in 2007. The process includes a pre-treatment on a biological trickling filter to partly degrade the organic load, followed by two vertical stages of partially saturated constructed wetlands for the removal of nitrogen by nitrification and denitrification. The reduction of phosphorus in the Azoe® system is achieved through the addition of FeCl3 as a coagulant, followed by filtration through the VFCWs. Phosphorus thus precipitated is thereby accumulated in the form of a Sludge Layer mostly at the surface of the 1st filter. Over time, the Sludge Layer progressively grows and may eventually release part of the accumulated phosphorus depending on the biophysicochemical conditions (Kim et al., 2013). The objective of this study was to determine the influence of pH on the solubilization of phosphorus from Sludge material sampled from a plant in operation. Results showed that the buffering capacity of the Sludge allowed to stabilize pH when in contact with moderately acidic (pH 4) or alkaline (pH 10) solutions. Under more drastic conditions, changes of pH were observed, but the release of phosphorus remained fairly low.
Patrick G. Hunt - One of the best experts on this subject based on the ideXlab platform.
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denitrification of nitrified and non nitrified swine lagoon wastewater in the suspended Sludge Layer of treatment wetlands
Ecological Engineering, 2009Co-Authors: Patrick G. Hunt, Kenneth C. Stone, T. A. Matheny, M. E. Poach, Matias B. Vanotti, Thomas F. DuceyAbstract:One method for managing livestock-wastewater N is the use of treatment wetlands. The objectives of this study were to (1) assess the magnitude of denitrification enzyme activity (DEA) in the suspended Sludge Layers of bulrush and cattail treatment wetlands, and (2) evaluate the impact of nitrogen pretreatment on DEA in the suspended Sludge Layer. The study used four wetland cells (3.6 m × 33.5 m) with two cells connected in series. Each wetland series received either untreated or partially nitrified swine wastewater from a single-cell anaerobic lagoon. The DEA of the suspended Sludge Layers of the constructed wetlands was measured by the acetylene inhibition method. The control DEA treatment for the Sludge Layer had a mean rate of 18 gN 2O-N g−1 Sludge h−1. Moreover, the potential DEA (nitrate-N and glucose-C added) mean was very large, 121 gN 2O-N g −1 Sludge h −1 . These DEA rates are consistent with the previously reported high levels of nitrogen removal by denitrification from these wetlands, especially when the wastewater was partially nitrified. Stepwise regression using distance within the wetland, wastewater nitrate, and wastewater ammonia explained much of the variation in DEA rates. In both bulrush and cattail wetlands, there were zones of very high potential DEA. Published by Elsevier B.V.
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Denitrification of nitrified and non-nitrified swine lagoon wastewater in the suspended Sludge Layer of treatment wetlands ☆
Ecological Engineering, 2009Co-Authors: Patrick G. Hunt, Kenneth C. Stone, T. A. Matheny, M. E. Poach, Matias B. Vanotti, Thomas F. DuceyAbstract:One method for managing livestock-wastewater N is the use of treatment wetlands. The objectives of this study were to (1) assess the magnitude of denitrification enzyme activity (DEA) in the suspended Sludge Layers of bulrush and cattail treatment wetlands, and (2) evaluate the impact of nitrogen pretreatment on DEA in the suspended Sludge Layer. The study used four wetland cells (3.6 m × 33.5 m) with two cells connected in series. Each wetland series received either untreated or partially nitrified swine wastewater from a single-cell anaerobic lagoon. The DEA of the suspended Sludge Layers of the constructed wetlands was measured by the acetylene inhibition method. The control DEA treatment for the Sludge Layer had a mean rate of 18 gN 2O-N g−1 Sludge h−1. Moreover, the potential DEA (nitrate-N and glucose-C added) mean was very large, 121 gN 2O-N g −1 Sludge h −1 . These DEA rates are consistent with the previously reported high levels of nitrogen removal by denitrification from these wetlands, especially when the wastewater was partially nitrified. Stepwise regression using distance within the wetland, wastewater nitrate, and wastewater ammonia explained much of the variation in DEA rates. In both bulrush and cattail wetlands, there were zones of very high potential DEA. Published by Elsevier B.V.