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  Page 7 - L'acide (4-chl...  
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CAG
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AST
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Les résultats ainsi obtenus ont indiqué que différentes doses d'UV (<1200mJ/cm2) et de peroxyde d'hydrogène (<15g/m3) ont entraîné une dégradation d'au moins 80% dans le cas de plusieurs herbicides chlorophénoxy (p. ex., le 2,4-D et l'acide trichloroacétique), soit un abaissement à moins de 0,1 µg/L de la concentration dans les effluents. La formation de bromates et de métabolites était négligeable; cependant, il fallait une filtration sur CAG après le traitement par UV/H2O2 afin d'éliminer le COA et le peroxyde d'hydrogène résiduel.
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Full-scale AOPs such as UV and hydrogen peroxide oxidation (UV/H2O2) treatment have been assessed for the reduction of different classes of pesticides (Kruithof et al., 2002a,b). Although MCPA was not studied specifically, other chlorophenoxy herbicides were studied. Results indicated that a variety of UV doses (<1200 mJ/cm2) and hydrogen peroxide doses (<15 g/m3) resulted in an 80% or greater degradation of several chlorophenoxy herbicides (e.g. 2,4-D and trichloroacetic acid) to effluent levels below 0.1 µg/L. Formation of bromate and metabolites was reported to be insignificant; however, GAC filtration was required following UV/H2O2 oxidation to remove AOC and residual hydrogen peroxide. This study also noted that the UV doses required for oxidation of pesticides were much higher than those needed for disinfection (Kruithof et al., 2002a,b).
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Dans d'autres études pilotes, on a eu recours à l'ozonation suivie d'un traitement au CAG et on a mesuré des taux d'élimination de 100% à des doses d'ozone de 2 à 4 mg/L et un temps de contact inférieur à 15 minutes (Foster et coll., 1992).
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WHO (2004) also recognizes ozonation as a suitable treatment technology for the reduction of MCPA to levels below 0.1 µg/L. Bonne et al. (2000) observed a 65% reduction of MCPA from influent levels of 20 µg/L to below 7 µg/L using ozonation alone and a reduction to effluent levels below 0.1 µg/L using combined ozonation and biological activated carbon filtration treatment. Additional pilot-scale studies using ozonation followed by GAC found 100% removal at ozone doses of 2-4 mg/L and contact times of less than 15 minutes (Foster et al., 1992). The potential presence of aliphatic acids, aldehydes, ketones and other ozonation by-products such as bromate and assimilable organic carbon (AOC) may require additional treatment following ozonation and/or process optimization to minimize by-product formation. Camel and Bermond (1998) reported that mineralization of pesticides using ozonation or other oxidation techniques is generally incomplete; as a result, water treatment process design using this method should include sand or GAC filtration following oxidation. It has also been suggested that the use of ozonation prior to GAC adsorption increases the biological activity of the filter bed and may extend the bed life for pesticide removal (Lambert and Graham, 1995).
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Les données d'exploitation provenant d'une usine de traitement municipale qui utilise les techniques traditionnelles avec un filtre d'adsorbtion au CAG ont montré que ce système de traitement pouvait faire passer de faibles concentrations de MCPA (de l'ordre de 0,47 µg/L) à moins de 0,02 µg/L (Frick et Dalton, 2005) dans l'influent.
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Operational data from a municipal-scale treatment plant using conventional treatment with a GAC filter-adsorber demonstrated that this type of treatment system can reduce low influent levels of MCPA from 0.47 µg/L to below 0.02 µg/L (Frick and Dalton, 2005). No information was provided on the operational conditions of the GAC adsorber used in this study. Pilot-scale study results indicated that post-filtration GAC adsorbers can reduce influent levels of 2 µg/L of MCPA to below 0.1 µg/L. No breakthrough of MCPA was observed over a period greater than 400 days using an EBCT of 20 minutes (Schippers et al., 2004). Other pilot-scale studies also found that GAC filtration was capable of reducing influent MCPA concentrations of 1 µg/L to below 0.1 µg/L; however, the bed life was not determined, as MCPA was only periodically present in the water supply (Hart, 1989; Hart and Chambers, 1991).
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Les données d'exploitation provenant d'une usine de traitement municipale qui utilise les techniques conventionnelles avec un filtre d'adsorbtion au CAG ont montré que ce système de traitement pouvait faire passer de faibles concentrations de MCPA (de l'ordre de 0,47 µg/L) à moins de 0,02 µg/L (Frick et Dalton, 2005) dans l'influent.
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Operational data from a municipal-scale treatment plant using conventional treatment with a GAC filter-adsorber demonstrated that this type of treatment system can reduce low influent MCPA levels of 0.47 µg/L to below 0.02 µg/L (Frick and Dalton, 2005). No information was provided on the operational conditions of the GAC adsorber used in this study. Pilot-scale study results indicated that post-filtration GAC adsorbers can reduce influent MCPA levels of 2 µg/L to below 0.1 µg/L. No breakthrough of MCPA was observed over a period greater than 400 days using an EBCT of 20 minutes (Schippers et al., 2004). Other pilot-scale studies also found that GAC filtration was capable of reducing influent MCPA concentrations of 1 µg/L to below 0.1 µg/L; however, the bed life was not determined, as MCPA was only periodically present in the water supply (Hart, 1989; Hart and Chambers, 1991).
  Page 8 - L'acide (4-chl...  
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Les données d'exploitation provenant d'une usine de traitement municipale qui utilise les techniques traditionnelles avec un filtre d'adsorbtion au CAG ont montré que ce système de traitement pouvait faire passer de faibles concentrations de MCPA (de l'ordre de 0,47 µg/L) à moins de 0,02 µg/L (Frick et Dalton, 2005) dans l'influent.
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Operational data from a municipal-scale treatment plant using conventional treatment with a GAC filter-adsorber demonstrated that this type of treatment system can reduce low influent levels of MCPA from 0.47 µg/L to below 0.02 µg/L (Frick and Dalton, 2005). No information was provided on the operational conditions of the GAC adsorber used in this study. Pilot-scale study results indicated that post-filtration GAC adsorbers can reduce influent levels of 2 µg/L of MCPA to below 0.1 µg/L. No breakthrough of MCPA was observed over a period greater than 400 days using an EBCT of 20 minutes (Schippers et al., 2004). Other pilot-scale studies also found that GAC filtration was capable of reducing influent MCPA concentrations of 1 µg/L to below 0.1 µg/L; however, the bed life was not determined, as MCPA was only periodically present in the water supply (Hart, 1989; Hart and Chambers, 1991).
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Les données d'exploitation provenant d'une usine de traitement municipale qui utilise les techniques traditionnelles avec un filtre d'adsorbtion au CAG ont montré que ce système de traitement pouvait faire passer de faibles concentrations de MCPA (de l'ordre de 0,47 µg/L) à moins de 0,02 µg/L (Frick et Dalton, 2005) dans l'influent.
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Operational data from a municipal-scale treatment plant using conventional treatment with a GAC filter-adsorber demonstrated that this type of treatment system can reduce low influent levels of MCPA from 0.47 µg/L to below 0.02 µg/L (Frick and Dalton, 2005). No information was provided on the operational conditions of the GAC adsorber used in this study. Pilot-scale study results indicated that post-filtration GAC adsorbers can reduce influent levels of 2 µg/L of MCPA to below 0.1 µg/L. No breakthrough of MCPA was observed over a period greater than 400 days using an EBCT of 20 minutes (Schippers et al., 2004). Other pilot-scale studies also found that GAC filtration was capable of reducing influent MCPA concentrations of 1 µg/L to below 0.1 µg/L; however, the bed life was not determined, as MCPA was only periodically present in the water supply (Hart, 1989; Hart and Chambers, 1991).
  Page 4 - L'acide (4-chl...  
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La formation de bromates et de métabolites était négligeable; cependant, il fallait une filtration sur CAG après le traitement par UV/peroxyde d'hydrogène afin d'éliminer le COA et le peroxyde d'hydrogène résiduel.
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Full-scale AOPs such as UV and hydrogen peroxide oxidation treatment have been assessed for the reduction of different classes of pesticides (Kruithof et al., 2002a,b). Although MCPA was not studied specifically, other chlorophenoxy herbicides were studied. Results indicated that a variety of UV doses (<1200 mJ/cm²) and hydrogen peroxide doses (<15 g/m³) resulted in an 80% or greater degradation of several chlorophenoxy herbicides (e.g., 2,4-D) to effluent levels below 0.1 µg/L. Formation of bromate and metabolites was reported to be insignificant; however, GAC filtration was required following UV/hydrogen peroxide oxidation to remove AOC and residual hydrogen peroxide. This study also noted that the UV doses required for oxidation of pesticides were much higher than those needed for disinfection (Kruithof et al., 2002a,b).
  Page 4 - L'acide (4-chl...  
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Les données d'exploitation provenant d'une usine de traitement municipale qui utilise les techniques conventionnelles avec un filtre d'adsorbtion au CAG ont montré que ce système de traitement pouvait faire passer de faibles concentrations de MCPA (de l'ordre de 0,47 µg/L) à moins de 0,02 µg/L (Frick et Dalton, 2005) dans l'influent.
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Operational data from a municipal-scale treatment plant using conventional treatment with a GAC filter-adsorber demonstrated that this type of treatment system can reduce low influent MCPA levels of 0.47 µg/L to below 0.02 µg/L (Frick and Dalton, 2005). No information was provided on the operational conditions of the GAC adsorber used in this study. Pilot-scale study results indicated that post-filtration GAC adsorbers can reduce influent MCPA levels of 2 µg/L to below 0.1 µg/L. No breakthrough of MCPA was observed over a period greater than 400 days using an EBCT of 20 minutes (Schippers et al., 2004). Other pilot-scale studies also found that GAC filtration was capable of reducing influent MCPA concentrations of 1 µg/L to below 0.1 µg/L; however, the bed life was not determined, as MCPA was only periodically present in the water supply (Hart, 1989; Hart and Chambers, 1991).
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La capacité du charbon actif à éliminer les pesticides par adsorption dépend de divers facteurs tels que la concentration, le pH, la compétition d'autres contaminants ou de matières organiques naturelles, le temps de contact et les propriétés physico-chimiques du pesticide. L'efficacité de la filtration sur charbon actif en grains (CAG) dépend également du temps de contact en fût vide (EBCT), du débit et de la durée du cycle de filtration.
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Activated carbon adsorption has been widely used to reduce the concentration of pesticides in drinking water and is recognized by WHO as a suitable treatment technology for the removal of MCPA to levels below 0.1 µg/L (Robeck et al., 1965; Miltner et al., 1989; Foster et al., 1992; Duguet et al., 1994; WHO, 2004). The capacity of activated carbon to remove pesticides by adsorption is affected by a variety of factors, such as concentration, pH, competition from other contaminants or natural organic matter, contact time and the physicochemical properties of the pesticide. The effectiveness of granular activated carbon (GAC) filtration is also a function of the empty bed contact time (EBCT), flow rate and filter run time. The effectiveness of powdered activated carbon is also a function of the carbon dosage.
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Dans d'autres études pilotes, on a eu recours à l'ozonation suivie d'un traitement au CAG et on a mesuré des taux d'élimination de 100% à des doses d'ozone de 2 à 4 mg/L et un temps de contact inférieur à 15 minutes (Foster et coll., 1992).
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WHO (2004) also recognizes ozonation as a suitable treatment technology for the reduction of MCPA to levels below 0.1 µg/L. Bonne et al. (2000) observed a 65% reduction of MCPA from influent levels of 20 µg/L to below 7 µg/L using ozonation alone and a reduction to effluent levels below 0.1 µg/L using combined ozonation and biological activated carbon filtration treatment. Additional pilot-scale studies using ozonation followed by GAC found 100% removal at ozone doses of 2-4 mg/L and contact times of less than 15 minutes (Foster et al., 1992). The potential presence of aliphatic acids, aldehydes, ketones and other ozonation by-products such as bromate and assimilable organic carbon (AOC) may require additional treatment following ozonation and/or process optimization to minimize by-product formation. Camel and Bermond (1998) reported that mineralization of pesticides using ozonation or other oxidation techniques is generally incomplete; as a result, water treatment process design using this method should include sand or GAC filtration following oxidation. It has also been suggested that the use of ozonation prior to GAC adsorption increases the biological activity of the filter bed and may extend the bed life for pesticide removal (Lambert and Graham, 1995).
  1,2-dichloroéthane dans...  
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L'U.S. EPA a identifié l'aération par tour à garnissage (ATG) et le charbon actif en grains (CAG) comme les meilleures techniques disponibles pour la suppression du 1,2-DCA dans l'eau potable et l'organisme considère qu'une réduction de 99 % est possible sous toutes les conditions anticipées (U.S. EPA, 1991b).
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A variety of configurations exist with respect to air stripping equipment, however, PTA provides an optimum system for the removal of VOCs from drinking water. PTA application allows for greater air-to-water ratios than other aeration systems (diffuser aerator, multiple tray aerator, spray aerator, mechanical aerator). In PTA, the contaminated water flows downward by gravity over a bed of packing material, while air is introduced into the tower below the packed bed and flows upward countercurrent to the water flow. As PTA transfers VOCs from water to air, treatment of the stripping tower off-gas to reduce the contaminant concentrations prior to discharge into the atmosphere may be necessary (Crittenden et al. 1988; Adams and Clark, 1991).
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L'U.S. EPA a identifié l'aération par tour à garnissage (ATG) et le charbon actif en grains (CAG) comme les meilleures techniques disponibles pour la suppression du 1,2-DCA dans l'eau potable et l'organisme considère qu'une réduction de 99 % est possible sous toutes les conditions anticipées (U.S. EPA, 1991b).
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A variety of configurations exist with respect to air stripping equipment, however, PTA provides an optimum system for the removal of VOCs from drinking water. PTA application allows for greater air-to-water ratios than other aeration systems (diffuser aerator, multiple tray aerator, spray aerator, mechanical aerator). In PTA, the contaminated water flows downward by gravity over a bed of packing material, while air is introduced into the tower below the packed bed and flows upward countercurrent to the water flow. As PTA transfers VOCs from water to air, treatment of the stripping tower off-gas to reduce the contaminant concentrations prior to discharge into the atmosphere may be necessary (Crittenden et al. 1988; Adams and Clark, 1991).
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Les niveaux moyens de formaldéhyde dans l'effluent de contacteurs à charbon actif en grains (CAG) se sont situés entre 0,3 et 0,6 µg/L.11La concentration de formaldéhyde a été réduite à des niveaux non détectables après passage d'une solution de substances humiques ozonée dans une colonne de CAG.9
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.11studied the formation and removal of formaldehyde at various treatment steps in an Edmonton drinking water pilot plant that was testing ozone. There was little removal of formaldehyde as a result of coagulation-flocculation-sedimentation treatment steps, although peak concentrations were reduced occasionally to an appreciable extent. As noted above, the mean concentration increased in raw water from 1.2 µg/L to 2.2 and 3.2 µg/L following ozonation at 0.5 and 1.0 mg ozone/mg non-volatile organic carbon, respectively. A significant reduction in formaldehyde formation was observed as the water temperature decreased. The subsequent dual-media filtration step decreased formaldehyde levels to between 0.5 and 0.9 µg/L for three of four filters tested. The mean effluent formaldehyde levels following granular activated carbon (GAC) contactors were in the range of 0.3-0.6 µg/L.11Formaldehyde was reduced to non-detectable levels when passed through a GAC column with a solution of ozonated humic material.9
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Les niveaux moyens de formaldéhyde dans l'effluent de contacteurs à charbon actif en grains (CAG) se sont situés entre 0,3 et 0,6 µg/L.11La concentration de formaldéhyde a été réduite à des niveaux non détectables après passage d'une solution de substances humiques ozonée dans une colonne de CAG.9
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.11studied the formation and removal of formaldehyde at various treatment steps in an Edmonton drinking water pilot plant that was testing ozone. There was little removal of formaldehyde as a result of coagulation-flocculation-sedimentation treatment steps, although peak concentrations were reduced occasionally to an appreciable extent. As noted above, the mean concentration increased in raw water from 1.2 µg/L to 2.2 and 3.2 µg/L following ozonation at 0.5 and 1.0 mg ozone/mg non-volatile organic carbon, respectively. A significant reduction in formaldehyde formation was observed as the water temperature decreased. The subsequent dual-media filtration step decreased formaldehyde levels to between 0.5 and 0.9 µg/L for three of four filters tested. The mean effluent formaldehyde levels following granular activated carbon (GAC) contactors were in the range of 0.3-0.6 µg/L.11Formaldehyde was reduced to non-detectable levels when passed through a GAC column with a solution of ozonated humic material.9
  Page 4 - Les toxines cy...  
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En résumé, le traitement privilégié lorsque c'est possible consiste à utiliser un oxydant comme l'ozone, le permanganate de potassium ou le chlore, et le CAG activé biologiquement après l'élimination des cellules d'algues.
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In summary, where feasible, the use of an oxidant such as ozone, potassium permanganate or chlorine and biologically activated GAC, after the removal of algal cells, is the preferred treatment. The specific concentrations of the various agents in the treatment process depend on the physical, chemical and biological quality of the water to be treated.46,52,58 More research is required on approaches for household treatment.
  L'ammoniac dans l'eau p...  
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Celle-ci requiert habituellement un polissage (par exemple, la filtration sur charbon actif granulaire [CAG]) et un post-traitement, comme une désinfection, pour faire en sorte qu'aucun organisme indésirable ou produit de croissance bactérienne ne passe dans le réseau de distribution (Wilczak, 2006a).
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The process may increase the level of nitrate and may release bacteria into the finished water. The finished water typically requires polishing (e.g., granular activated carbon [GAC] filtration) and post-treatment, such as disinfection, to ensure that neither undesirable organisms nor growth products pass into the distribution system (Wilczak, 2006a).
  OPFLP-01: Concentration...  
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Actin-R - antisens - 23 bases = 5'-CCG ATC CAG ACG GAG TAT TTC CT-3'
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432 - forward - 20 bases = 5'-TGG ACI CGY GGI CCY AAY CA-3'
  OPFLP-07 Détection du v...  
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SH-Poly-A (sens) 26 bases = 5' - GAR TTT ACT CAG TGT TCA ATG AAT GT - 3'
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SH-Poly-1 (reverse) 20 bases = 5' - GGC ATA GCT GCA GGA AAA TT -3'
  Publications et confére...  
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www.cag-acg.ca
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May 29-June 6, 2004
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CAG - charbon actif granulé
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AST - aspartate aminotransferase
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Une mise en garde s'impose aussi : les centres de dialyse devraient être informés si la source d'eau de leur usine de traitement locale est vulnérable aux proliféra-tions d'algues bleues, ce qui pourrait les inciter à sou-mettre l'eau à un traitement supplémentaire au besoin. Ce traitement peut varier d'une filtration CAG suivie d'une osmose inverse jusqu'à des systèmes beaucoup plus complexes de filtration sur membrane (p. ex., ultra-filtration).
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Also, as a precautionary note, dialysis centres should be aware or informed if the source water from their local treatment plant is prone to blue-green algal blooms so that they may undertake to provide additional treatment of the water, if necessary. This treatment can range from GAC filtration followed by reverse osmosis to much more complex membrane filtration systems (e.g., ultrafiltration). The extent of additional treatment will depend entirely on the quality of the municipal water supply. Continuous monitoring of performance and equipment will be required to ensure adequate quality of the water. As well, it is important that all manufacturers' specifications be evaluated for the local conditions.
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Les données d'exploitation provenant d'une usine de traitement municipale qui utilise les techniques conventionnelles avec un filtre d'adsorbtion au CAG ont montré que ce système de traitement pouvait faire passer de faibles concentrations de MCPA (de l'ordre de 0,47 µg/L) à moins de 0,02 µg/L (Frick et Dalton, 2005) dans l'influent.
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Operational data from a municipal-scale treatment plant using conventional treatment with a GAC filter-adsorber demonstrated that this type of treatment system can reduce low influent MCPA levels of 0.47 µg/L to below 0.02 µg/L (Frick and Dalton, 2005). No information was provided on the operational conditions of the GAC adsorber used in this study. Pilot-scale study results indicated that post-filtration GAC adsorbers can reduce influent MCPA levels of 2 µg/L to below 0.1 µg/L. No breakthrough of MCPA was observed over a period greater than 400 days using an EBCT of 20 minutes (Schippers et al., 2004). Other pilot-scale studies also found that GAC filtration was capable of reducing influent MCPA concentrations of 1 µg/L to below 0.1 µg/L; however, the bed life was not determined, as MCPA was only periodically present in the water supply (Hart, 1989; Hart and Chambers, 1991).
  Page 5 - Recommandation...  
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On signale des problèmes de fuites précoces avec les filtres à charbon actif granulé (CAG), lorsque tous les sites d'adsorption ont été comblés, peutêtre par des composés organiques concurrents comme des matières organiques naturelles, et qu'il ne reste que le mécanisme de réduction qui soit fonctionnel.
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(1) Chlorine dioxide generator tuning: Chlorine dioxide generator design and performance have a large impact on the amount of chlorite ion formed during chlorine dioxide production. Precise operation ("tuning"), proper maintenance and the generation technology employed with the chlorine dioxide generator have a large bearing on the chlorine dioxide production efficiency and the rate at which chlorite and other undesirable by-products, such as chlorate, hydrogen peroxide and perchlorate, are formed and fed into the water with the chlorine dioxide dose. The onsite production of chlorine dioxide can be technically challenging for the operator. Minor leaks can lead to potentially dangerous white crystalline material which can be ignited if it contacts strong reducing agents or if it is subjected to spark, flame, friction or compression. Any spills should be immediately flushed with copious amounts of water (Gates, 1998).
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Dans d'autres études pilotes, on a eu recours à l'ozonation suivie d'un traitement au CAG et on a mesuré des taux d'élimination de 100% à des doses d'ozone de 2 à 4 mg/L et un temps de contact inférieur à 15 minutes (Foster et coll., 1992).
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WHO (2004) also recognizes ozonation as a suitable treatment technology for the reduction of MCPA to levels below 0.1 µg/L. Bonne et al. (2000) observed a 65% reduction of MCPA from influent levels of 20 µg/L to below 7 µg/L using ozonation alone and a reduction to effluent levels below 0.1 µg/L using combined ozonation and biological activated carbon filtration treatment. Additional pilot-scale studies using ozonation followed by GAC found 100% removal at ozone doses of 2-4 mg/L and contact times of less than 15 minutes (Foster et al., 1992). The potential presence of aliphatic acids, aldehydes, ketones and other ozonation by-products such as bromate and assimilable organic carbon (AOC) may require additional treatment following ozonation and/or process optimization to minimize by-product formation. Camel and Bermond (1998) reported that mineralization of pesticides using ozonation or other oxidation techniques is generally incomplete; as a result, water treatment process design using this method should include sand or GAC filtration following oxidation. It has also been suggested that the use of ozonation prior to GAC adsorption increases the biological activity of the filter bed and may extend the bed life for pesticide removal (Lambert and Graham, 1995).
  Recommandations pour la...  
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L'adsorption sur CAG est souvent employée pour réduire les concentrations de COV dans l'eau potable. On estime que cette méthode permet de réduire de 99 % (U.S. EPA, 1985, 2003b; Lykins et Clark, 1994) les concentrations de tétrachlorure de carbone et d'obtenir ainsi des concentrations inférieures à 1 µg/L dans l'eau traitée lorsque les conditions opérationnelles sont raisonnables (O'Brian et coll., 1981; Lykins et coll., 1984; AWWA, 1991).
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EPA Method 551.1 uses liquid-liquid extraction and gas chromatography with linearized electrolytic conductivity detectors and has an MDL range of 0.002-0.006 µg/L (U.S. EPA, 1995). A detection limit range is cited, as multiple detection limits are possible due to variability in reagents, instrumentation, and/or laboratory analyst performance.
  Le tétrachlorure de car...  
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L'adsorption sur CAG est souvent employée pour réduire les concentrations de COV dans l'eau potable. On estime que cette méthode permet de réduire de 99 % (U.S. EPA, 1985, 2003b; Lykins et Clark, 1994) les concentrations de tétrachlorure de carbone et d'obtenir ainsi des concentrations inférieures à 1 µg/L dans l'effluent lorsque les conditions opérationnelles sont raisonnables (O'Brian et coll., 1981; Lykins et coll., 1984; AWWA, 1991).
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EPA Method 551.1 uses liquid-liquid extraction and gas chromatography with linearized electrolytic conductivity detectors and has an MDL range of 0.002-0.006 µg/L (U.S. EPA, 1995). A detection limit range is cited, as multiple detection limits are possible due to variability in reagents, instrumentation, and/or laboratory analyst performance.
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D'autres méthodes de traitement par strippage à l'air pourraient permettre de réduire la concentration de tétrachlorure de carbone dans l'eau potable, notamment l'aération diffuse, l'aération par barbotage à étapes multiples, l'aération par plateaux et l'aération par plateaux peuprofonds. Ces technologies peuvent être particulièrement utiles pour les petits systèmes où le traitement par CAG ou ATG n'est pas possible (U.S. EPA, 1998).
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Full-scale data demonstrated that the use of GAC operating with a flow rate of 40 gallons per minute (0.22 ML/day), a total empty bed contact time (EBCT) of 130 min, and a carbon usage rate of 11.6 lb/1000 gallons (1.4 kg/m³) was capable of reducing influent carbon tetrachloride concentrations of 72.9 mg/L to an effluent concentration of below 1 µg/L (O'Brian et al., 1981). Another treatment facility operating with a flow rate of 0.23 million gallons per day (0.87 ML/day) and using a downflow GAC adsorber with an EBCT of 35 min and a carbon depth of 9 ft. (2.7 m) reported that influent concentrations of carbon tetrachloride of 6 µg/L could be reduced to below 1 µg/L (AWWA, 1991).
  L'ammoniac dans l'eau p...  
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Dans une étude à pleine échelle, on a comparé un filtre simple (de sable) de taille moyenne avec un filtre double (de sable et de CAG) du point de vue de l'efficacité à éliminer l'ammoniac présent en concentration inférieure à 0,2 mg NH4+/L (soit 0,15 mg NH3-N/L) dans un influent à basse température.
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A full-scale study compared a single-medium (sand) filter with a dual-media (sand and GAC) filter for the removal of an influent ammonia concentration below 0.2 mg NH4+/L (0.15 mg NH3-N/L) at low temperature. The dual-media filter showed no ammonia breakthrough at a temperature of 2ºC, whereas the single-medium filter allowed approximately 20% of the influent ammonia to pass through. However, the dual-media filter provided no advantages over the single-layer filter at temperatures greater than 7ºC (Bablon et al., 1988).
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La combinaison de l'ATG suivi par l'adsorption sur CAG en tant que traitement en deux étapes a été proposée comme étant la méthode la plus efficace pour obtenir de faibles concentrations de COV dans l'eau traitée.
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Adams and Clark (1991) estimated the cost-effective design parameters for liquid-phase GAC treatment of carbon tetrachloride in drinking water. The estimated carbon usage rate to reduce an influent carbon tetrachloride concentration of 100 µg/L to an effluent concentration of 5 µg/L was 0.25/1000 gallons (0.03 kg/m³) using an EBCT of 15 min and a bed life of 168 days. Under these conditions, a 95% reduction of carbon tetrachloride in drinking water may be achievable.
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