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Bergeron P.,Rivages Pro Technology Technopole Izarbel | Oujati H.,Lonza Bioscience SAS | Catalan Cuenca V.,Labaqua | Huguet Mestre J.M.,Aigues de Barcelona | Courtois S.,Suez Environment CIRSEE
International Journal of Hygiene and Environmental Health | Year: 2011

For accompanying actions to pollution crisis management of recreational waters, rapid methods providing a quantified faecal indicator which can be completed in less than half a day, are currently needed. Two sensitive rRNA-targeted Reverse Transcription-quantitative PCR (RT-qPCR) methods were developed for quantifying Escherichia coli and Enterococcus spp. cells in marine bathing waters. Threshold cycle (Ct) values were found to be linear with a target quantity over a 4log dynamic range (from 105 to 100 cell equivalents per 100ml). In order to confirm the scope of application of such alternative methods, 80 and 85 seawater samples from the Atlantic Ocean and Mediterranean sea were analysed by both RT-qPCR and ISO culture-based methods for E. coli and Enterococcus spp. enumerations. This study demonstrates that by giving reliable results in 3. h, the RT-qPCR method has high potential as a rapid test for recreational water quality monitoring. In natural waters, significant linear log-log relations between the RT-qPCR and culture method measurements for E. coli and Enterococcus spp. assays were shown (correlation coefficient (r) values of 0.814 and 0.715, p< 0.0001, respectively). The sensitivities (defined as the probability of a sample testing positive if the criterion number is exceeded) of RT-qPCR for E. coli and Enterococcus spp. were respectively 94.4% and 83.9%. By contrast, specificities (defined as the probability of a test being negative if a contamination is truly absent) could be considered as lower (65.9% and 50.0% for E. coli and Enterococcus spp.). This reflects that RT-qPCR assays detect all viable cells (culturable and non-culturable) whereas culture methods only detect cells which are viable and culturable. © 2011 Elsevier GmbH.

Martin Ruel S.,CIRSEE | Choubert J.M.,IRSTEA | Esperanza M.,CIRSEE | Miege C.,IRSTEA | And 5 more authors.
Water Science and Technology | Year: 2011

The next challenge of wastewater treatment is to reliably remove micro-pollutants at the microgram per litre range in order to meet reuse applications and contribute to reach the good status of the water bodies. A hundred priority and relevant emerging substances were measured to evaluate at full-scale the removal efficiencies of seven advanced treatment lines (one membrane bioreactor process and six tertiary treatment lines) that were designed for reuse applications. To reliably compare the processes, specific procedures for micro-pollutants were applied for sampling, analysis and calculation of removal efficiencies. The membrane bioreactor process allowed to upgrade the removal efficiencies of about 20% of the substances measured, especially those that were partially degraded during conventional processes. Conventional tertiary processes like high rate clarification, sand filtration and polishing pond achieved significant removal for some micro-pollutants, especially for adsorbable substances. Advanced tertiary processes, like ozonation, activated carbon and reverse osmosis were all very efficient to complete the removal of polar pesticides and pharmaceuticals; metals and less polar substances were better retained by reverse osmosis. © IWA Publishing 2011.

Schlosser O.,Suez Environnement | Huyard A.,Suez Environnement | Catalan V.,Labaqua
Water Science and Technology | Year: 2011

The objective of this study was to assess workers' exposure to bioaerosols in sludge drying units. Simultaneous collection of inhalable dust and airborne biological agents was carried out using rotating cup samplers (CIP 10, Arelco). Sixteen stationary and 30 personal measurements were performed in three drying plants, during summer and winter. Microbial content of air was characterized by high amounts of Gram-negative bacteria, endotoxin, and thermophilic actinomycetes. High differences between exposure levels were observed with regard to workplaces and tasks. Dryers and conveyors in operation were closed, and the monitoring task in the dryer room was associated with low levels of personal exposure, close to background levels. Conversely, cleaning and maintenance of the dryer and conveyors required the equipment to be opened, giving significantly higher task-based personal exposure levels. The fall of dried sludge into indoor containers resulted in high emission and spreading of dust. Mean personal exposure levels to fungi were moderate or low for all tasks. Based on the results of this study, appropriate means of operational control and personal protection are being developed and implemented on sites. © IWA Publishing 2011.

Martin Ruel S.,CIRSEE | Esperanza M.,CIRSEE | Choubert J.-M.,IRSTEA | Valor I.,Labaqua | And 2 more authors.
Water Science and Technology | Year: 2010

The next challenge of wastewater treatment is to reliably remove micropollutants at the microgram per litre range in order to reduce the discharge for priority substances and to meet the environmental quality standards set by the European Water Framework Directive. The present work assessed the occurrence of 60 organic substances (priority substances and other relevant pollutants) in municipal wastewater and sludge. Their fate in the treatment processes and their removal efficiencies were quantified. Thorough on-site mass balances were carried out at 8 municipal wastewater treatment plants chosen among conventional and advanced secondary processes. It was found that 70% of the substances were quantified in raw wastewater and 50% in effluent, with a transfer without a limited degradation for most of them. Low loaded activated sludge (AS) process reduced the emission of more than half of micropollutants. At low sludge retention time (AS under high load), lower removal efficiencies were measured compared to low loaded AS. No influence of temperature of the biological reactor was shown. The membrane bioreactor process increased the removal efficiencies for one third of the substances that were partially removed with AS. Still, five substances were measured at concentrations exceeding the environmental quality standards at the outlet of the studied plants. In addition to efforts for source-reduction, complementary treatments need to be set-up. © IWA Publishing 2010.

Ventura F.,AGBAR Aigues de Barcelona | Quintana J.,AGBAR Aigues de Barcelona | Gomez M.,Labaqua | Velo-Cid M.,Augas de Galicia
Bulletin of Environmental Contamination and Toxicology | Year: 2010

A study of organic compounds which caused several odor problems in water supplies from NW Spain was carried out. Sour dish-cloths, potato bin and musty were the main descriptors associated with these events. Closed loop stripping analysis combined with sensory-GC and GC/MS detection was used. The compound producing the initial odor event was 3,5-dimethyl-2-methoxypyrazine, identified for the first time as the compound responsible for odor incidents in finished water. Concentration levels were up to 300 ng/L in the effluent from an activated sludge wastewater treatment plant (WWTP) and 3 ng/L in finished water. 3-isobutyl-2-methoxypyrazine and other alkyl methoxypyrazines were the compounds responsible for the odor events that occurred several months later. Concentration levels in the mg/L range were measured in the activated sludge of a WWTP. © 2010 Springer Science+Business Media, LLC.

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