Christian Volk - Academia.edu (original) (raw)
Papers by Christian Volk
Limnology and Oceanography, 1997
Plug‐flow biofilm reactors colonized by microorganisms in streamwater were used to measure the co... more Plug‐flow biofilm reactors colonized by microorganisms in streamwater were used to measure the concentration and composition of biodegradable dissolved organic C (BDOC) in White Clay Creek. During the 4‐month study period, DOC ranged from 0.8 to 10.4 mg C liter‒1 and was, on average, composed of 75% humic substances, 13% carbohydrates, 2% amino acids, and 18% >100 kDa. The carbohydrates were predominantly polysaccharides, nearly all amino acids were present in the combined form, and most carbohydrates and amino acids were humic bound. BDOC ranged from 0.2 to 2.9 mg C liter‒1, averaged 25% of the DOC, and was composed of 75% humic substances, 30% carbohydrates, 4% amino acids, and 39% DOC >100 kDa. The carbohydrate portion of the BDOC was primarily polysaccharide or humic bound. Similarly, the amino acid portion of the BDOC was overwhelmingly present in the combined form and primarily humic bound. Glycine and aspartic acid were the dominant amino acids in White Clay Creek DOC a...
Revue des sciences de l'eau, 1992
La mesure de la matière organique biodégradable dans l'eau est déterminée à partir de tests b... more La mesure de la matière organique biodégradable dans l'eau est déterminée à partir de tests biologiques qui reposent sur deux concepts. Le premier est basé sur le suivi de la croissance de souches pures ou d'une population bactérienne mixte dans un échantillon d'eau. Le maximum de croissance obtenu est converti en Carbone Organique facilement Assimilable (COA) et exprimé en µg de C eq. acétate/l en tenant compte du rendement de croissance de ces bactéries dans des solutions d'acétate de sodium. Le second repose sur le suivi de la décroissance du Carbone Organique Dissous (COD) dans un échantillon d'eau ensemencé par une flore bactérienne indigène des eaux (flore en suspension ou flore fixée sur des particules de sable). La matière organique biadégradée est exprimée sous forme de Carbone Organique Dissous Biodégradable (CODB). Des essais ont été réalisés sur différents types d'eau (eaux de rivière de la Seine, de l'Oise et de la Marne, eaux en cours de tra...
Ingénieur de l'EN!TA-Dijon Contrôle de la matière organique biodégradable au cours des trait... more Ingénieur de l'EN!TA-Dijon Contrôle de la matière organique biodégradable au cours des traitements d'oxydation et de la distribution des eaux d'alimentation Soutenue le 01 / 04 /1994
Water Research, 2000
ÐThe presence of biodegradable organic matter (BOM) can aect drinking water quality. A variety of... more ÐThe presence of biodegradable organic matter (BOM) can aect drinking water quality. A variety of treatment processes can be used to control BOM during drinking water production. Studies of enhanced coagulation (coagulation optimized for removal of dissolved organic material as well as particles) showed that removal of DOC could be improved from the current average of 29% (plant conditions termed baseline coagulation) to an average of 43% for optimized coagulation at the 10 sites tested. Similarly, removal of biodegradable dissolved organic carbon (BDOC) could be improved from the current baseline level of 30% to 38% through the application of optimized coagulation. At lower pH, ferric coagulants generally performed better for removal of organic carbon than did alum or polyaluminum chloride. In most of the cases, assimilable organic carbon (AOC) was not aected by coagulation, probably because the AOC fraction was composed of small molecular weight, non-humic compounds that are not amenable to coagulation.
Water Research, 2000
ÐThis study describes the in¯uence of dierent corrosion control programs on corrosion rates, and ... more ÐThis study describes the in¯uence of dierent corrosion control programs on corrosion rates, and the short-term eects of various levels of corrosiveness on bacterial water quality in model drinking water distribution systems. Corrosion rates were strongly related to seasons and water temperature. This suggests that slightly higher corrosion inhibitor concentrations would be required during summer and possibly lower dosages during winter months. Over a one-year period, bacterial water quality data were similar in new pipes receiving waters with dierent corrosiveness and phosphate levels, suggesting that corrosion aects bacterial water quality over longer periods of time.
Cancer Genetics and Cytogenetics, 1989
Environmental Science & Technology, 2005
Natural organic matter (NOM) in drinking water supplies can provide precursors for disinfectant b... more Natural organic matter (NOM) in drinking water supplies can provide precursors for disinfectant byproducts, molecules that impact taste and odors, compounds that influence the efficacy of treatment, and other compounds that are a source of energy and carbon for the regrowth of microorganisms during distribution. NOM, measured as dissolved organic carbon (DOC), was monitored daily in the White River and the Indiana-American water treatment plant over 22 months. Other parameters were either measured daily (UV-absorbance, alkalinity, color, temperature) or continuously (turbidity, pH, and discharge) and used with stepwise linear regressions to predict DOC concentrations. The predictive models were validated with monthly samples of the river water and treatment plant effluent taken over a 2-year period after the daily monitoring had ended. Biodegradable DOC (BDOC) concentrations were measured in the river water and plant effluent twice monthly for 18 months. The BDOC measurements, along with measurements of humic and carbohydrate constituents within the DOC and BDOC pools, revealed that carbohydrates were the organic fraction with the highest percent removal during treatment, followed by BDOC, humic substances, and refractory DOC.
Applied and Environmental Microbiology, 1999
This study evaluated the impacts of reducing nutrient levels on bacterial water quality in drinki... more This study evaluated the impacts of reducing nutrient levels on bacterial water quality in drinking water. Two American Water System facilities (sites NJ102a and IN610) with histories of coliform problems were involved, and each water utility received two pilot distribution systems (annular reactors). One reactor simulated the conventional treatment conditions (control), while the other reactor was used to assess the effect of biological filtration and subsequent reduced biodegradable organic matter levels on suspended (water column) and biofilm bacterial concentrations in the distribution systems. Biodegradable organic matter levels were reduced approximately by half after biological treatment. For site NJ102a, the geometric mean of the assimilable organic carbon concentrations was 217 μg/liter in the plant effluent and 91 μg/liter after biological filtration. For both sites, plant effluent biodegradable dissolved organic carbon levels averaged 0.45 mg/liter, versus 0.19 to 0.22 mg...
Proceedings of the Indiana Academy of Science, Apr 9, 2014
Http Www Theses Fr, 1994
Controle de la matière organique biodégradable au cours des traitements d'oxydation et de la dist... more Controle de la matière organique biodégradable au cours des traitements d'oxydation et de la distribution des eaux d'alimentation SOMMAIRE INTRODUCTION i CHAPITRE I-MESURE DE LA MATIERE ORGANIQUE BIODEGRADABLE DES EAUX (Etude méthodologique). s Les différentes méthodes de mesure de la matière organique biodégradable des eaux. 6 Méthode de mesure du CODB utilisant un inoculum bactérien fixé sur du sable. 9 Situation du problème et objectifs de l'étude. 12 Références bibliographiques. 14 I) Effet des conditions expérimentales sur la valeur de CODB mesurée à l'aide d'un inoculum bactérien mixte fixé ou en suspension et comparaison des teneurs en CODB déterminées par ces deux méthodes. *° ^Comparison of two techniques for measuring biodegradable dissolved organic carbon in water" 16 1) Introduction. 18 1.1) BDOC determination using suspended bacteria. 18 1.2) BDOC determination using bacteria fixed on sand. 2) Materials and methods. 2.1) BDOC determination using bacteria fixed on sand. 20 2.2) BDOC determination using suspended bacteria. 2.3) Epifluorescent counts. 3) Results and discussion. 3.1) BDOC determination using bacteria fixed on sand. 3.1.1) Effect of the inoculum size. 3.1.2) Effect of the incubation period. 3.1.3) Effect of aeration conditions. IV 3.2) BDOC determination using suspended bacteria. 28 3.2.1) Effect of the inoculum size. 28 3.2.2) Effect of the incubation period. 28 3.2.3) Effect of aeration. 29 3.3) Comparison of BDOC values obtained with suspended or sand fixed bacteria. 30 4) Conclusion. 34 5) References 34 II) Signification de la mesure du CODB: relation entre CODB et croissance de souches bactériennes pures et d'une flore naturelle mixte. 37 " La mesure du CODB: un index du potentiel de reviviscence bactérienne des eaux. " 37 1) Introduction. 39 2) Matériel et méthodes. 42 2.1) Préparation de la verrerie. 2.2) Préparation des cultures de Pseudomonas fluoréscens Pî 7 et Spirillum NOX. 2.3) Suivi de la croissance bactérienne de Pseudomonas fluorescens PI7. 2.4) Suivi de la croissance de Pseudomonas fluorescens PI 7 + Spirillum NOX 2.5) Suivi de la croissance d'une flore mixte. 43 2.6) Mesure du CODB en présence de bactéries fixées sur du sable. 43 3) Résultats et discussion. 3.1) Relation entre CODB et maximum de croissance d'une souche pure de Pseudomonas fluorescens P17. 3.2) Relation entre le CODB, la croissance de Pseudomonas fluorescens PI7 et Spirillum NOX et le COA. 3.3) Relation entre CODB et recroissance d'une flore bactérienne mixte. 4) Conclusion. 5) Références bibliographiques. CHAPITRE II-EFFET DE L'OXYDATION SUR LA PRODUCTION DE CODB (étude de laboratoire). 54 Situation du problème et objectifs de l'étude. Références bibliographiques. V I) L'ozone. 59 "Effect of ozone on the production of biodegradable dissolved organic carbon (BDOQ during water treatment " 59 1) Introduction. 61 2) Materials and methods. 64 2. l)Origin and characteristics of water samples studied. 64 2.2) Ozone production. 65 2.3) Oxidation test with ozone. 65 2.4) Measurements. 66 3) Results and discussion. 66 3.1) Effects of the applied ozone dose. 67 3.2) Effect of contact time. 71 3.3) Effect of applied ozone dose-contact time (CT) combination. 73 4) Conclusion. 78 5) References. 80 II) Le couplage ozone peroxyde d'hydrogène. "Effect of ozone-hydrogen peroxide combination on the formation of biodegradable dissolved organic carbon. " 1) Introduction. 84 2) Materials and methods. 2.1) Characteristics of water samples studied. 86 2.2) Ozone production. 2.3) Oxidation test with ozone and ozone/hydrogen peroxide. 2.4) Measurements. 3) Results and discussion. 3.1) Effects of hydrogen peroxide/ozone ratio. 3.2) Effect of ozone dose at a constant hydrogen peroxide/ ozone ratio. 92 3.3) Effect of contact time. 96 4) Conclusion. 98 5) References. 99 VI Ill) L'ozone catalytique. 101 "Comparison of the effect of ozone, ozone hydrogen peroxide system and catalytic ozone on the biodegradable organic matter ofafulvic acid solution. " 101 1) Introduction. 102 2) Materials and methods. 104 3) Results and discussion. 105 4) Conclusions. Ill 5) References. 112 CHAPITRE III-CODB ET RECROISSANCE BACTERIENNE LE LONG D'UN RESEAU DE DISTRIBUTION (étude de terrain). Situation du problème et objectifs de l'étude.
Journal American Water Works Association, May 1, 2000
Methods in Enzymology, 2001
Publisher Summary This chapter presents the methods available to evaluate biodegradable organic m... more Publisher Summary This chapter presents the methods available to evaluate biodegradable organic matter concentrations in water, and describes and compares several bioassays commonly used in the drinking water field to assess the bacterial regrowth potential of waters. Because a high biodegradable organic matter (BOM) level is one factor related to bacterial regrowth, BOM removal should be emphasized during water treatment to improve water quality. There is a weak correlation between organic carbon (AOC) and biodegradable dissolved organic carbon (BDOC) concentrations. The BDOC test attempts to identify the entire pool of BOM, including very labile constituents to slowly biodegradable molecules (requiring the successive steps of cell adsorption, exoenzymatic hydrolysis, and cell consumption), whereas the AOC test detects easily assimilable organic compounds. Because both tests emphasize different fractions of biodegradable organic matter, both parameters should be monitored when studying nutrient changes during water treatment and distribution. Because of a long incubation period, using the BDOC suspended bacteria method is not practical at a water utility. A water utility can use either the sand or bioreactor methodology, depending on its testing objectives. Both methods yield to a similar BDOC result. The BDOC sand measurement is recommended for a short study or a limited number of samples.
Encyclopedia of Environmental Microbiology, 2003
Measurement of Organic Matter and its Biodegradable Fraction Removal of Organic Matter During Dri... more Measurement of Organic Matter and its Biodegradable Fraction Removal of Organic Matter During Drinking Water Treatment Bacterial Regrowth in Distribution Systems Keywords: assimilable organic carbon (AOC) in drinking water; biodegradable dissolved organic carbon (BDOC); drinking water; modeling; coliform regrowth in water distribution systems; methodology; organic matter in water; organic matter removal in water treatment; regrowth of bacteria in water distribution systems; water distribution systems; water treatment plants
Water Research, 1997
In this study, the effects of ozone, ozone-hydrogen peroxide and catalytic ozone were assessed fr... more In this study, the effects of ozone, ozone-hydrogen peroxide and catalytic ozone were assessed from changes in the organic constituents of a synthetic solution of fulvic acids. Initial DOC and BDOC concentrations of the fulvic acid solution were 2.84 mg L-~ and 0.23 mg L-~, respectively. Oxidation tests were performed according to the Ozotest method, which provides an assessment of the extent of oxidation. Ozone, ozone-hydrogen peroxide and catalytic ozone mineralized 15 %, 18 % and 24% of the initial DOC, respectively. The oxidation system that generated the highest BDOC concentrations was ozone-hydrogen peroxide, while catalytic ozone produced the lowest concentrations (with ozone doses greater than 3.5 mg L-~, BDOC levels were 0.90 mg L-~, 0.80 mg L-~ and 0.60 mg L-~ for ozone-hydrogen peroxide, ozone and catalytic ozone, respectively). Catalytic ozone induced oxidation of ozone by-products into CO2, and led to the greatest reduction in chlorine demand.
Tumor Biology - TUMOR BIOL, 1992
A neural origin of Ewing’s sarcoma (ES) has often been suggested and we have demonstrated neurofi... more A neural origin of Ewing’s sarcoma (ES) has often been suggested and we have demonstrated neurofilament protein expression in ES cells. However, only the 200-kD subunit has been revealed in all of the ES cells analyzed. The 160- and 68-kD subunits were always absent. For these reasons, we have attempted to induce neural differentiation in 3 ES cell lines with different types of inducers: tetradecanoylphorbol-13-acetate (TPA) retinoic acid and nerve growth factor. When the cell lines were cultured for 7 days with TPA (10-9M) or retinoic acid (10-7M), only the 68-kD neurofilament subunit was slightly induced. No inducation was obtained when nerve growth factor was used, even at a 21-day culture. These results are in agreement with the putative neural origin of ES and may indicate an abnormal expression of neurofilament proteins in this tumor.
Journal of Environmental Engineering and Science, 2002
Drinking water utilities may have to consider changing disinfectant to improve water quality and ... more Drinking water utilities may have to consider changing disinfectant to improve water quality and meet more stringent disinfection regulations. The objective of this study was to evaluate the response of a full-scale drinking water distribution system to a change in disinfectant from chlorine to chlorine dioxide, in terms of its impact on microbiological stability and disinfection by-product formation. Chlorine dioxide residuals were consistently present above detection limits throughout the distribution system (>0.20 mg/L). Over a study period of 3.5 months, no degradation of bacterial water quality occurred after implementing the new disinfectant. Chlorine dioxide maintained total bacteria (microscopic counts) and heterotrophic plate count levels below 2 x 105 cells/mL and 1000 CFU/mL, respectively. The change in disinfectant from chlorine to chlorine dioxide led to an 85% reduction in trihalomethanes (i.e., from 30 to 5 μμg/L) and a 60% reduction in haloacetic acids (i.e., from...
Environmental Technology, 1994
This article compared two methods for measuring biodegradable dissolved organic carbon(BDOC) conc... more This article compared two methods for measuring biodegradable dissolved organic carbon(BDOC) concentrations in water. These techniques consist of following the reduction of dissolved organic carbon(DOC) in water samples incubated either for 30 days with ...
Cancer Genetics and Cytogenetics, 1987
Limnology and Oceanography, 1997
Plug‐flow biofilm reactors colonized by microorganisms in streamwater were used to measure the co... more Plug‐flow biofilm reactors colonized by microorganisms in streamwater were used to measure the concentration and composition of biodegradable dissolved organic C (BDOC) in White Clay Creek. During the 4‐month study period, DOC ranged from 0.8 to 10.4 mg C liter‒1 and was, on average, composed of 75% humic substances, 13% carbohydrates, 2% amino acids, and 18% >100 kDa. The carbohydrates were predominantly polysaccharides, nearly all amino acids were present in the combined form, and most carbohydrates and amino acids were humic bound. BDOC ranged from 0.2 to 2.9 mg C liter‒1, averaged 25% of the DOC, and was composed of 75% humic substances, 30% carbohydrates, 4% amino acids, and 39% DOC >100 kDa. The carbohydrate portion of the BDOC was primarily polysaccharide or humic bound. Similarly, the amino acid portion of the BDOC was overwhelmingly present in the combined form and primarily humic bound. Glycine and aspartic acid were the dominant amino acids in White Clay Creek DOC a...
Revue des sciences de l'eau, 1992
La mesure de la matière organique biodégradable dans l'eau est déterminée à partir de tests b... more La mesure de la matière organique biodégradable dans l'eau est déterminée à partir de tests biologiques qui reposent sur deux concepts. Le premier est basé sur le suivi de la croissance de souches pures ou d'une population bactérienne mixte dans un échantillon d'eau. Le maximum de croissance obtenu est converti en Carbone Organique facilement Assimilable (COA) et exprimé en µg de C eq. acétate/l en tenant compte du rendement de croissance de ces bactéries dans des solutions d'acétate de sodium. Le second repose sur le suivi de la décroissance du Carbone Organique Dissous (COD) dans un échantillon d'eau ensemencé par une flore bactérienne indigène des eaux (flore en suspension ou flore fixée sur des particules de sable). La matière organique biadégradée est exprimée sous forme de Carbone Organique Dissous Biodégradable (CODB). Des essais ont été réalisés sur différents types d'eau (eaux de rivière de la Seine, de l'Oise et de la Marne, eaux en cours de tra...
Ingénieur de l'EN!TA-Dijon Contrôle de la matière organique biodégradable au cours des trait... more Ingénieur de l'EN!TA-Dijon Contrôle de la matière organique biodégradable au cours des traitements d'oxydation et de la distribution des eaux d'alimentation Soutenue le 01 / 04 /1994
Water Research, 2000
ÐThe presence of biodegradable organic matter (BOM) can aect drinking water quality. A variety of... more ÐThe presence of biodegradable organic matter (BOM) can aect drinking water quality. A variety of treatment processes can be used to control BOM during drinking water production. Studies of enhanced coagulation (coagulation optimized for removal of dissolved organic material as well as particles) showed that removal of DOC could be improved from the current average of 29% (plant conditions termed baseline coagulation) to an average of 43% for optimized coagulation at the 10 sites tested. Similarly, removal of biodegradable dissolved organic carbon (BDOC) could be improved from the current baseline level of 30% to 38% through the application of optimized coagulation. At lower pH, ferric coagulants generally performed better for removal of organic carbon than did alum or polyaluminum chloride. In most of the cases, assimilable organic carbon (AOC) was not aected by coagulation, probably because the AOC fraction was composed of small molecular weight, non-humic compounds that are not amenable to coagulation.
Water Research, 2000
ÐThis study describes the in¯uence of dierent corrosion control programs on corrosion rates, and ... more ÐThis study describes the in¯uence of dierent corrosion control programs on corrosion rates, and the short-term eects of various levels of corrosiveness on bacterial water quality in model drinking water distribution systems. Corrosion rates were strongly related to seasons and water temperature. This suggests that slightly higher corrosion inhibitor concentrations would be required during summer and possibly lower dosages during winter months. Over a one-year period, bacterial water quality data were similar in new pipes receiving waters with dierent corrosiveness and phosphate levels, suggesting that corrosion aects bacterial water quality over longer periods of time.
Cancer Genetics and Cytogenetics, 1989
Environmental Science & Technology, 2005
Natural organic matter (NOM) in drinking water supplies can provide precursors for disinfectant b... more Natural organic matter (NOM) in drinking water supplies can provide precursors for disinfectant byproducts, molecules that impact taste and odors, compounds that influence the efficacy of treatment, and other compounds that are a source of energy and carbon for the regrowth of microorganisms during distribution. NOM, measured as dissolved organic carbon (DOC), was monitored daily in the White River and the Indiana-American water treatment plant over 22 months. Other parameters were either measured daily (UV-absorbance, alkalinity, color, temperature) or continuously (turbidity, pH, and discharge) and used with stepwise linear regressions to predict DOC concentrations. The predictive models were validated with monthly samples of the river water and treatment plant effluent taken over a 2-year period after the daily monitoring had ended. Biodegradable DOC (BDOC) concentrations were measured in the river water and plant effluent twice monthly for 18 months. The BDOC measurements, along with measurements of humic and carbohydrate constituents within the DOC and BDOC pools, revealed that carbohydrates were the organic fraction with the highest percent removal during treatment, followed by BDOC, humic substances, and refractory DOC.
Applied and Environmental Microbiology, 1999
This study evaluated the impacts of reducing nutrient levels on bacterial water quality in drinki... more This study evaluated the impacts of reducing nutrient levels on bacterial water quality in drinking water. Two American Water System facilities (sites NJ102a and IN610) with histories of coliform problems were involved, and each water utility received two pilot distribution systems (annular reactors). One reactor simulated the conventional treatment conditions (control), while the other reactor was used to assess the effect of biological filtration and subsequent reduced biodegradable organic matter levels on suspended (water column) and biofilm bacterial concentrations in the distribution systems. Biodegradable organic matter levels were reduced approximately by half after biological treatment. For site NJ102a, the geometric mean of the assimilable organic carbon concentrations was 217 μg/liter in the plant effluent and 91 μg/liter after biological filtration. For both sites, plant effluent biodegradable dissolved organic carbon levels averaged 0.45 mg/liter, versus 0.19 to 0.22 mg...
Proceedings of the Indiana Academy of Science, Apr 9, 2014
Http Www Theses Fr, 1994
Controle de la matière organique biodégradable au cours des traitements d'oxydation et de la dist... more Controle de la matière organique biodégradable au cours des traitements d'oxydation et de la distribution des eaux d'alimentation SOMMAIRE INTRODUCTION i CHAPITRE I-MESURE DE LA MATIERE ORGANIQUE BIODEGRADABLE DES EAUX (Etude méthodologique). s Les différentes méthodes de mesure de la matière organique biodégradable des eaux. 6 Méthode de mesure du CODB utilisant un inoculum bactérien fixé sur du sable. 9 Situation du problème et objectifs de l'étude. 12 Références bibliographiques. 14 I) Effet des conditions expérimentales sur la valeur de CODB mesurée à l'aide d'un inoculum bactérien mixte fixé ou en suspension et comparaison des teneurs en CODB déterminées par ces deux méthodes. *° ^Comparison of two techniques for measuring biodegradable dissolved organic carbon in water" 16 1) Introduction. 18 1.1) BDOC determination using suspended bacteria. 18 1.2) BDOC determination using bacteria fixed on sand. 2) Materials and methods. 2.1) BDOC determination using bacteria fixed on sand. 20 2.2) BDOC determination using suspended bacteria. 2.3) Epifluorescent counts. 3) Results and discussion. 3.1) BDOC determination using bacteria fixed on sand. 3.1.1) Effect of the inoculum size. 3.1.2) Effect of the incubation period. 3.1.3) Effect of aeration conditions. IV 3.2) BDOC determination using suspended bacteria. 28 3.2.1) Effect of the inoculum size. 28 3.2.2) Effect of the incubation period. 28 3.2.3) Effect of aeration. 29 3.3) Comparison of BDOC values obtained with suspended or sand fixed bacteria. 30 4) Conclusion. 34 5) References 34 II) Signification de la mesure du CODB: relation entre CODB et croissance de souches bactériennes pures et d'une flore naturelle mixte. 37 " La mesure du CODB: un index du potentiel de reviviscence bactérienne des eaux. " 37 1) Introduction. 39 2) Matériel et méthodes. 42 2.1) Préparation de la verrerie. 2.2) Préparation des cultures de Pseudomonas fluoréscens Pî 7 et Spirillum NOX. 2.3) Suivi de la croissance bactérienne de Pseudomonas fluorescens PI7. 2.4) Suivi de la croissance de Pseudomonas fluorescens PI 7 + Spirillum NOX 2.5) Suivi de la croissance d'une flore mixte. 43 2.6) Mesure du CODB en présence de bactéries fixées sur du sable. 43 3) Résultats et discussion. 3.1) Relation entre CODB et maximum de croissance d'une souche pure de Pseudomonas fluorescens P17. 3.2) Relation entre le CODB, la croissance de Pseudomonas fluorescens PI7 et Spirillum NOX et le COA. 3.3) Relation entre CODB et recroissance d'une flore bactérienne mixte. 4) Conclusion. 5) Références bibliographiques. CHAPITRE II-EFFET DE L'OXYDATION SUR LA PRODUCTION DE CODB (étude de laboratoire). 54 Situation du problème et objectifs de l'étude. Références bibliographiques. V I) L'ozone. 59 "Effect of ozone on the production of biodegradable dissolved organic carbon (BDOQ during water treatment " 59 1) Introduction. 61 2) Materials and methods. 64 2. l)Origin and characteristics of water samples studied. 64 2.2) Ozone production. 65 2.3) Oxidation test with ozone. 65 2.4) Measurements. 66 3) Results and discussion. 66 3.1) Effects of the applied ozone dose. 67 3.2) Effect of contact time. 71 3.3) Effect of applied ozone dose-contact time (CT) combination. 73 4) Conclusion. 78 5) References. 80 II) Le couplage ozone peroxyde d'hydrogène. "Effect of ozone-hydrogen peroxide combination on the formation of biodegradable dissolved organic carbon. " 1) Introduction. 84 2) Materials and methods. 2.1) Characteristics of water samples studied. 86 2.2) Ozone production. 2.3) Oxidation test with ozone and ozone/hydrogen peroxide. 2.4) Measurements. 3) Results and discussion. 3.1) Effects of hydrogen peroxide/ozone ratio. 3.2) Effect of ozone dose at a constant hydrogen peroxide/ ozone ratio. 92 3.3) Effect of contact time. 96 4) Conclusion. 98 5) References. 99 VI Ill) L'ozone catalytique. 101 "Comparison of the effect of ozone, ozone hydrogen peroxide system and catalytic ozone on the biodegradable organic matter ofafulvic acid solution. " 101 1) Introduction. 102 2) Materials and methods. 104 3) Results and discussion. 105 4) Conclusions. Ill 5) References. 112 CHAPITRE III-CODB ET RECROISSANCE BACTERIENNE LE LONG D'UN RESEAU DE DISTRIBUTION (étude de terrain). Situation du problème et objectifs de l'étude.
Journal American Water Works Association, May 1, 2000
Methods in Enzymology, 2001
Publisher Summary This chapter presents the methods available to evaluate biodegradable organic m... more Publisher Summary This chapter presents the methods available to evaluate biodegradable organic matter concentrations in water, and describes and compares several bioassays commonly used in the drinking water field to assess the bacterial regrowth potential of waters. Because a high biodegradable organic matter (BOM) level is one factor related to bacterial regrowth, BOM removal should be emphasized during water treatment to improve water quality. There is a weak correlation between organic carbon (AOC) and biodegradable dissolved organic carbon (BDOC) concentrations. The BDOC test attempts to identify the entire pool of BOM, including very labile constituents to slowly biodegradable molecules (requiring the successive steps of cell adsorption, exoenzymatic hydrolysis, and cell consumption), whereas the AOC test detects easily assimilable organic compounds. Because both tests emphasize different fractions of biodegradable organic matter, both parameters should be monitored when studying nutrient changes during water treatment and distribution. Because of a long incubation period, using the BDOC suspended bacteria method is not practical at a water utility. A water utility can use either the sand or bioreactor methodology, depending on its testing objectives. Both methods yield to a similar BDOC result. The BDOC sand measurement is recommended for a short study or a limited number of samples.
Encyclopedia of Environmental Microbiology, 2003
Measurement of Organic Matter and its Biodegradable Fraction Removal of Organic Matter During Dri... more Measurement of Organic Matter and its Biodegradable Fraction Removal of Organic Matter During Drinking Water Treatment Bacterial Regrowth in Distribution Systems Keywords: assimilable organic carbon (AOC) in drinking water; biodegradable dissolved organic carbon (BDOC); drinking water; modeling; coliform regrowth in water distribution systems; methodology; organic matter in water; organic matter removal in water treatment; regrowth of bacteria in water distribution systems; water distribution systems; water treatment plants
Water Research, 1997
In this study, the effects of ozone, ozone-hydrogen peroxide and catalytic ozone were assessed fr... more In this study, the effects of ozone, ozone-hydrogen peroxide and catalytic ozone were assessed from changes in the organic constituents of a synthetic solution of fulvic acids. Initial DOC and BDOC concentrations of the fulvic acid solution were 2.84 mg L-~ and 0.23 mg L-~, respectively. Oxidation tests were performed according to the Ozotest method, which provides an assessment of the extent of oxidation. Ozone, ozone-hydrogen peroxide and catalytic ozone mineralized 15 %, 18 % and 24% of the initial DOC, respectively. The oxidation system that generated the highest BDOC concentrations was ozone-hydrogen peroxide, while catalytic ozone produced the lowest concentrations (with ozone doses greater than 3.5 mg L-~, BDOC levels were 0.90 mg L-~, 0.80 mg L-~ and 0.60 mg L-~ for ozone-hydrogen peroxide, ozone and catalytic ozone, respectively). Catalytic ozone induced oxidation of ozone by-products into CO2, and led to the greatest reduction in chlorine demand.
Tumor Biology - TUMOR BIOL, 1992
A neural origin of Ewing’s sarcoma (ES) has often been suggested and we have demonstrated neurofi... more A neural origin of Ewing’s sarcoma (ES) has often been suggested and we have demonstrated neurofilament protein expression in ES cells. However, only the 200-kD subunit has been revealed in all of the ES cells analyzed. The 160- and 68-kD subunits were always absent. For these reasons, we have attempted to induce neural differentiation in 3 ES cell lines with different types of inducers: tetradecanoylphorbol-13-acetate (TPA) retinoic acid and nerve growth factor. When the cell lines were cultured for 7 days with TPA (10-9M) or retinoic acid (10-7M), only the 68-kD neurofilament subunit was slightly induced. No inducation was obtained when nerve growth factor was used, even at a 21-day culture. These results are in agreement with the putative neural origin of ES and may indicate an abnormal expression of neurofilament proteins in this tumor.
Journal of Environmental Engineering and Science, 2002
Drinking water utilities may have to consider changing disinfectant to improve water quality and ... more Drinking water utilities may have to consider changing disinfectant to improve water quality and meet more stringent disinfection regulations. The objective of this study was to evaluate the response of a full-scale drinking water distribution system to a change in disinfectant from chlorine to chlorine dioxide, in terms of its impact on microbiological stability and disinfection by-product formation. Chlorine dioxide residuals were consistently present above detection limits throughout the distribution system (>0.20 mg/L). Over a study period of 3.5 months, no degradation of bacterial water quality occurred after implementing the new disinfectant. Chlorine dioxide maintained total bacteria (microscopic counts) and heterotrophic plate count levels below 2 x 105 cells/mL and 1000 CFU/mL, respectively. The change in disinfectant from chlorine to chlorine dioxide led to an 85% reduction in trihalomethanes (i.e., from 30 to 5 μμg/L) and a 60% reduction in haloacetic acids (i.e., from...
Environmental Technology, 1994
This article compared two methods for measuring biodegradable dissolved organic carbon(BDOC) conc... more This article compared two methods for measuring biodegradable dissolved organic carbon(BDOC) concentrations in water. These techniques consist of following the reduction of dissolved organic carbon(DOC) in water samples incubated either for 30 days with ...
Cancer Genetics and Cytogenetics, 1987