871 resultados para wastewater discharge


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Discharge of Mortgage signed by Henry Kalar, President of the Niagara Permanent Building Society stating that John McNeilly [?] has satisfied all money due and the mortgage is therefore discharged. The right hand side of this document is burned. Text is slightly affected, Aug. 8, 1853.

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Le présent projet vise à documenter la nécessité d’augmenter notre connaissance de la présence des contaminants organiques tels que les médicaments dans l’environnement et d’évaluer leur devenir environnemental. On a étudié la présence de composés pharmaceutiques dans différents échantillons d'eau. On a focalisé nos efforts spécialement sur les échantillons d'eau de l'usine d'épuration de la Ville de Montréal et ses effluents, les eaux de surface avoisinantes et l’eau du robinet dans la région de Montréal. Pour ce faire, on a tout d’abord développé deux méthodes analytiques automatisées basées sur la chromatographie liquide avec extraction en phase solide (SPE) couplée à la chromatographie liquide couplée à la spectrométrie de masse en tandem (LC-MS/MS). On a également étudié les performances des trois techniques d'ionisation à pression atmosphérique (API), pour ensuite les utiliser dans la méthode analytique développée. On a démontré que l'ionisation par électronébulisation (ESI) est une méthode d'ionisation plus efficace pour l'analyse des contaminants pharmaceutiques dans des échantillons de matrices très complexes comme les eaux usées. Une première méthode analytique SPE couplée à la LC-MS/MS a été développée et validée pour l'étude des échantillons complexes provenant de l'usine d'épuration de la Ville de Montréal et des eaux de surface près de l'usine. Cinq médicaments de prescription ont été étudiés: le bézafibrate (un régulateur de lipides), le cyclophosphamide et le méthotrexate (deux agents anticancéreux), l'orlistat (un agent anti-obésité) et l’énalapril (utilisé dans le traitement de l'hypertension). La plupart de ces drogues sont excrétées par le corps humain et rejetées dans les eaux usées domestiques en faisant par la suite leur chemin vers les usines municipales de traitement des eaux usées. On a pu démontrer qu'il y a un faible taux d’élimination à l'usine d'épuration pour le bézafibrate et l'énalapril. Ces deux composés ont aussi été détectés dans les eaux de surface sur un site à proximité immédiate de la décharge de l’effluent de la station d'épuration. i En observant la nécessité de l'amélioration des limites de détection de la première méthode analytique, une deuxième méthode a été développée. Pour la deuxième méthode, un total de 14 contaminants organiques, incluant trois agents anti-infectieux (clarithromycin, sulfaméthoxazole et triméthoprime), un anticonvulsant (carbamazépine) et son produit de dégradation (10,11-dihydrocarbamazépine), l'agent antihypertensif (enalapril), deux antinéoplastiques utilisés en chimiothérapie (cyclophosphamide et méthotrexate), des herbicides (atrazine, cyanazine, et simazine) et deux produits de transformation de l’atrazine (deséthylatrazine et déisopropylatrazine) ainsi qu’un agent antiseptique (triclocarban). Ces produits ont été quantifiés dans les eaux de surface ainsi que dans l’eau du robinet. L'amélioration des limites de détection pour cette méthode a été possible grâce à la charge d'un volume d'échantillon supérieur à celui utilisé dans la première méthode (10 mL vs 1 mL). D'autres techniques de confirmation, telles que les spectres des ions produits utilisant une pente d’énergie de collision inverse dans un spectromètre de masse à triple quadripôle et la mesure des masses exactes par spectrométrie de masse à temps d’envol, ont été explorées. L'utilisation d'un analyseur de masse à temps d’envol a permis la confirmation de 6 des 14 analytes. Finalement, étant donné leur haute toxicité et pour évaluer leur persistance et leur transformation au niveau du traitement des eaux potables, la cinétique d'oxydation du cyclophosphamide et de méthotrexate avec l'ozone moléculaire et des radicaux OH a été étudiée. Les constantes de dégradation avec l'ozone moléculaire ont été calculées et la qualité de l'eau après traitement a pu être évaluée. Le rendement du processus d'ozonation a été amélioré pour la cyclophosphamide dans les eaux naturelles, en raison de la combinaison de réactions directes et indirectes. Cette étude a montré que l'ozone est très efficace pour oxyder le méthotrexate mais que le cyclophosphamide serait trop lent à s’oxyder pour un traitement efficace aux conditions usuelles de traitement de l’eau potable.

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A recently established strain collection of freshwater microalgae native to Quebec was examined for physiological diversity. The 100 strains appeared very heterogeneous in terms of growth when they were cultured at 10±2 °C or 22±2 °C on the secondary effluent from a municipal wastewater treatment plant (WW) and defined BBM medium. Scatterplots were used to examine the diversity in physiology that might be present in the collection. These showed a number of interesting results. There was a fair amount of dispersion in growth rates by media type independent of temperature. Surprisingly considering that all the isolates had been initially enriched on BBM, the distribution was quite symmetrical around the iso-growth line, suggesting that enrichment on BBM did not seem to bias the cells for growth on this medium versus WW. As well, considering that all the isolates had been initially enriched at 22 °C, it is quite surprising that the distribution of specific growth rates was quite symmetrical around the iso-growth line with roughly equal numbers of isolates found on either side. Thus enrichment at 22 °C does not seem to bias the cells for growth at this temperature versus 10°C. The scatterplots obtained when the percentage lipid of cultures grown on BBM were compared with cultures grown on WW at either 10 °C or 22 °C made it apparent that lipid production was favored by growth on WW at either temperature and that lipid production does not seem to be particularly favored by one temperature over the other. When the collection was queried for differences with respect to sampling location, statistical analysis showed that roughly the same degree of physiological diversity was found with samples from the two different aggregate locations.

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School of Environmental Studies, Cochin University of Science and Technology

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Faculty of Engineering. Cochin University of Science and Technology

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A high power Nz laser of the double-Blumlein type having a modified gas flow system, electrode configuration, and discharge geometry with minimum inductance is described. By incorporating a triggere’d-pressurized spark gap switch, arc-free operation was achieved for a wide E/P range. The device gives a peak power in excess of 700 kW with a FWHM of 3 ns and an efficiency of 0.51%, which is remarkably high for a pulsed nitrogen laser system. The dependence of output power on parameters such as operating pressure, voltage, and repetition rate are discussed.

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The photoemission optogalvanic (POG) effect has been investigated in a neon-neodymium hollow cathode discharge using cw laser excitation. Both positive and negative effects were observed. It was found that the amplitude of the POG signal was unstable near the instability region of the discharge.

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We report the experimental observation of subcritical Hopf bifurcation and the existence of non-oscillating “windows” in the dynamics of a Ne-Nd hollow cathode discharge current as the control parameter.

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Doppler limited high resolution spectrum in the wavelength region 17224 to 17236 cm−1 of the first positive system (B 3Π g −A 3Σ u + ) of the N2 molecule is recorded by optogalvanic spectroscopic technique using a single mode ring dye laser. It is observed that the intensity and line width of the rotational line increase with the discharge current. Dependence of the collision broadening coefficient on the current was also evaluated.

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The thesis entitled Growth Response of Phytoplankton Exposed to Industrial Effluents in River Periyar. The present investigation has been conducted in two phases: field observation and algal assays. The monthly distribution of hydrographic features is represented graphically. The sampling year has been divided into three seasons: monsoon (June to September), postmonsoon (October to January) and premonsoon (February to May). The data were analysed using Student's t-test to find whether there was any significant difference between surface and bottom samples. The spatial variation of the variables was assessed by Page's L (trend) test (Ray Meddis, 1975). The standard procedure for algal toxicity test (Ward and Parrish, 1982) was followed throughout the study. Statistical analysis (Page's L (trend) test) showed that there was no significant difference in Secchi disc transparency between the stations. The field observations as well as the laboratory assays confirm that the rate of discharge in river Periyar during premonsoon is insufficient to effect dilution of wastewater received in the industrial zone.

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The nearshore marine ecosystem is a dynamic environment impacted by many activities, especially the coastal waters and sediments contiguous to major urban areas. Although heavy metals are natural constituents of the marine environment, inputs are considered to be conservative pollutants and are potentially toxic, accumulate in the sediment, are bioconcentrated by organisms and may cause health problems to humans via the food chain. A variety of metals in trace amounts are essential for biological processes in all organisms, but excessive levels can be detrimental by acting as enzyme inhibitors. Discharge of industrial wastewater, agriculture runoff and untreated sewage pose a particularly serious threat to the coastal environment of Kerala, but there is a dearth of studies in documenting the contaminant metals. This study aimed principally to assess such contamination by examining the results of heavy metal (Cu, Pb, Cr, Ni, Zn, Cd and Hg) analysis in seawater, sediment and benthic biota from a survey of five transects along the central and northern coast of Kerala in 2008 covering a 10.0 km stretch of near shore environment in each transect. Trophic transfer of metal contaminants from aquatic invertebrates to its predators was also assessed, by employing a suitable benthic food chain model in order to understand which all metals are undergoing biotransference (transfer of metals from a food source to consumer).The study of present contamination levels will be useful for potential environmental remediation and ecosystem restoration at contaminated sites and provides a scientific basis for standards and protective measures for the coastal waters and sediments. The usefulness of biomonitor proposed in this study would allow identification of different bioavailable metals as well as provide an assessment of the magnitude of metal contamination in the coastal marine milieu. The increments in concentration of certain metals between the predator and prey discerned through benthic food chain can be interpreted as evidence of biotransference.

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The present study aims at the investigation of the 1ysico—chemical features of a tropical tidal river viz. we Muvattupuzha river. This river is expected to receive Jderate to heavy pollution loads in years to come, from we lone industrial unit, already set up on its bank. ilike other rivers, the geographical disposition of this Lver attains unique importance as regards its dynamics for 3) availability of natural runoff water from catchment :eas, which becomes very heavy during the monsoon season 3) regular steady availability of tail race water from a /dro—electric power station throughout the yearThe study also aims at arriving at the balancing forces of inherent self~purification of the river verses pollution loads from the factory effluents. The investigation period falls ahead of actual pollution occurrence and so the ambient conditions for a period of nearly one-and-a—half years were investigated, the analyses of which providflz to formulate the inter-relations of parameters varying with seasons. Tracer experiments were carried out which revealed the dispersion and dilution characteristics of the river in the vicinity of effluent outfall. The studv covers the trial—cum-capacity production periods of the factory during which effluents of various strength and quantity were discharged into the river; a few computed values arQ’cjmpgrQdl ... with the observed values. The base data along with the profiles of Oxygen sag equation have been utilized fb develop a mathematical model of the river with regard to its water quality