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Indicator Systems for Assessing Public Health Risk in WatersRoop, Daniel Oliver 26 April 2012 (has links)
For over one hundred years, indicator organisms such as coliforms have been measured as an index of public health risk from transmission of waterborne diseases. Even so, waterborne disease outbreaks have occurred in systems with negative coliform results, many traced to viral or protozoan etiologies. Conversely, no discernible public health outcomes have occurred in systems with positive coliform results. These inconsistencies arise because coliforms, as bacteria, respond differently to environmental stressors and engineered treatment processes than protozoan and viral pathogens. Recent reviews of four decades of indicator and pathogen monitoring indicated that coliphages are more highly correlated to pathogen presence in a variety of waters than coliforms. Therefore, the goal of this research was to re-examine a variety of traditional and novel indicator systems to determine their value as indicators, either singly or as a toolbox. We collected samples of animal feces, wastewaters, source waters and treated drinking waters. Samples were collected from four geographical regions of the United States (Northeast, South, Midwest and West) to assess spatial variability and in all four seasons to assess temporal variability. Samples were monitored for total coliforms, E. coli, male-specific and somatic coliphages, and other physical and chemical water quality parameters including organic carbon, pH and turbidity. The detection of coliforms and E. coli in this study's drinking waters suggests fecal contamination and supports the need for indicator monitoring in drinking water systems. The strength of bacterial indicators (coliforms and E. coli) was supported in this study by the fact that there was no seasonal variance in wastewaters or drinking waters. In addition, coliforms and E. coli did not vary by region in drinking waters. Male-specific and somatic coliphages proved to be promising indicators. In this study, male-specific coliphages correlated to bacterial indicators in animal feces. Both coliphages were able to survive various environmental conditions, wastewater treatment, and drinking water treatment processes. Neither of the coliphages varied by season in untreated drinking waters. An area of concern for both male-specific and somatic coliphages was the high level of non-detects. The thermotolerance of male-specific coliphages is also an area of concern for its use as a good universal indicator.
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Molecular level separation of arsenic (V) from drinking water using cationic micelles and ultrafiltration membraneErgican, Erdogan. January 2005 (has links)
Thesis (Ph.D.)--University of Nevada, Reno, 2005. / "December 2005." Includes bibliographical references. Online version available on the World Wide Web.
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The Impacts of UV Direct Photolysis and UV/H2O2 Advanced Oxidation Processes on the Formation of Nitrosamines and Organic Chloramines from Subsequent Chlor(am)inationHarvey, Monica 20 January 2010 (has links)
Ultraviolet direct photolysis (UV) and the advanced oxidation process UV/H2O2 are new technologies in the water treatment industry. Both treatments can cause the transformation of organic compounds. Nitrosamines and organic chloramines are disinfection by-products (DBPs) formed from the reaction of organic nitrogen compounds during chlorination or chloramination (chlor(am)ination) disinfection. It is therefore possible for UV and UV/H2O2 to affect the organic compound precursors for nitrosamines and organic chloramines and thus their formation from subsequent chlor(am)ination. The precursor compounds, UV and H2O2 doses used for UV or UV/H2O2, and alkalinity were found to have an effect on the formation of nitrosamines and organic chloramines during bench-scale experiments. Full scale studies found UV and UV/H2O2 had different effects on the formation of different nitrosamine species and organic chloramine concentrations, and that a potential correlation existed between the formation of organic chloramines from chlorination and the formation of N-nitrosodimethylamine from chloramination.
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The Impacts of UV Direct Photolysis and UV/H2O2 Advanced Oxidation Processes on the Formation of Nitrosamines and Organic Chloramines from Subsequent Chlor(am)inationHarvey, Monica 20 January 2010 (has links)
Ultraviolet direct photolysis (UV) and the advanced oxidation process UV/H2O2 are new technologies in the water treatment industry. Both treatments can cause the transformation of organic compounds. Nitrosamines and organic chloramines are disinfection by-products (DBPs) formed from the reaction of organic nitrogen compounds during chlorination or chloramination (chlor(am)ination) disinfection. It is therefore possible for UV and UV/H2O2 to affect the organic compound precursors for nitrosamines and organic chloramines and thus their formation from subsequent chlor(am)ination. The precursor compounds, UV and H2O2 doses used for UV or UV/H2O2, and alkalinity were found to have an effect on the formation of nitrosamines and organic chloramines during bench-scale experiments. Full scale studies found UV and UV/H2O2 had different effects on the formation of different nitrosamine species and organic chloramine concentrations, and that a potential correlation existed between the formation of organic chloramines from chlorination and the formation of N-nitrosodimethylamine from chloramination.
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Evaluating the effects of strain selection on the attenuation of Bacillus subtilis spores through saturated porous mediaGray, Leslie Susanna January 2013 (has links)
Increasingly stringent water quality regulations concerning microbiological parameters govern the use of groundwater resources that are vulnerable to mixing with surface waters. These drinking water sources are at higher risk for infiltration by pathogenic microorganisms, including the oocysts of the human enteroparasite Cryptosporidium spp. Cryptosporidium can cause severe gastroenteritis in humans, and the characteristics of Cryptosporidium oocysts, including low infectious dose, high resistance to inactivation, and long survival in the environment pose a significant risk to public health if present in treated drinking water. Bacillus subtilis is widely used as a surrogate for biocolloid transport in saturated porous media, and recognized as a conservative indicator for the transport of Cryptosporidium parvum oocysts during filtration. However, no study has directly compared the transport of spores from different strains within the Bacillus subtilis species. Strain variability has the potential to impact retention in porous media based on differences in size and electrophoretic mobility.
The transport behaviour of four strains of Bacillus subtilis (wild-type and laboratory type, subspecies subtilis and subspecies spizizenii; 1.9 to 2.9µm diameter) is contrasted in this research to two sizes of fluorescent polystyrene microspheres (1.1µm and 4.5µm diameter) through packed saturated crushed quartz sand. A peristaltic pump was used to introduce (bio)colloids into the duplicate column apparatus at a loading rate of 0.1m/day. (Bio)colloid removal was assessed and compared by constructing breakthrough curves of normalized concentrations and box-and-whisker diagrams of percent removal of Bacillus subtilis strains.
Under unfavourable conditions minimal reduction (<0.22log10) in effluent spore concentration was observed over the column depth of 15cm. In favourable attachment conditions up to 0.69 log10 reduction was observed but the sampling schedule employed was insufficient to clearly identify a pseudo steady-state plateau. An analysis of variance was used to determine the statistical significance of spore strain, subspecies, and type. A significant difference between the four strains was observed at the lower ionic strength, with spore subspecies and type affecting spore removal in unfavourable conditions (p < 0.05). Some sensitivity to settling and laboratory storage suggests that standardized sample handling procedures are required. Differences observed here between the strains of Bacillus subtilis spores indicate that riverbank filtration performance assessments and drinking water treatment plant process demonstrations may benefit from a recommended strain for use.
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Occurrence and Seasonal Variability of Selected Pharmaceuticals in Southern Ontario Drinking Water SuppliesKormos, Jennifer January 2007 (has links)
The presence and seasonal variability of human and veterinary pharmaceuticals in surface water (raw water) and treated water samples from two drinking water facilities in Southern Ontario was investigated. Water samples were collected at monthly intervals for one year to characterize the seasonal variability of these contaminants. The presence of these compounds in raw water samples collected from groundwater wells, which were potentially under the influence of surface water, was also examined. All samples were extracted by solid phase extraction (SPE) techniques and analyzed by liquid chromatography coupled with tandem mass spectrometry (LC-ESI-MS/MS). The compounds detected represented different therapeutic classes, including antibiotics, lipid regulating agents and anti-inflammatory drugs. The concentrations detected for most compounds were in the low ng/L range, with one compound being detected close to 1 μg/L. In general, human pharmaceuticals (i.e. gemfibrozil, ibuprofen and carbamazepine) were detected in raw and treated water samples, while the antibiotics were not detected after treatment. Seasonal variability was observed in the concentrations and compounds detected, which could be partially explained by changes in surface water hydrology and sources of contamination. The results demonstrate that the application of conventional treatment technologies were not very effective in reducing some of these compounds from a drinking water facility. In contrast, a second drinking water facility using additional treatment technologies, including ozonation and granular activated carbon (GAC) filters, could reduce the concentrations of these contaminants. Although, the presence of these contaminants in surface water represents a potential risk, the results suggest that appropriate treatment can minimize exposure to at least some of these emerging contaminants.
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Occurrence and Seasonal Variability of Selected Pharmaceuticals in Southern Ontario Drinking Water SuppliesKormos, Jennifer January 2007 (has links)
The presence and seasonal variability of human and veterinary pharmaceuticals in surface water (raw water) and treated water samples from two drinking water facilities in Southern Ontario was investigated. Water samples were collected at monthly intervals for one year to characterize the seasonal variability of these contaminants. The presence of these compounds in raw water samples collected from groundwater wells, which were potentially under the influence of surface water, was also examined. All samples were extracted by solid phase extraction (SPE) techniques and analyzed by liquid chromatography coupled with tandem mass spectrometry (LC-ESI-MS/MS). The compounds detected represented different therapeutic classes, including antibiotics, lipid regulating agents and anti-inflammatory drugs. The concentrations detected for most compounds were in the low ng/L range, with one compound being detected close to 1 μg/L. In general, human pharmaceuticals (i.e. gemfibrozil, ibuprofen and carbamazepine) were detected in raw and treated water samples, while the antibiotics were not detected after treatment. Seasonal variability was observed in the concentrations and compounds detected, which could be partially explained by changes in surface water hydrology and sources of contamination. The results demonstrate that the application of conventional treatment technologies were not very effective in reducing some of these compounds from a drinking water facility. In contrast, a second drinking water facility using additional treatment technologies, including ozonation and granular activated carbon (GAC) filters, could reduce the concentrations of these contaminants. Although, the presence of these contaminants in surface water represents a potential risk, the results suggest that appropriate treatment can minimize exposure to at least some of these emerging contaminants.
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Impact of Design and Operational Parameters on Rapid, Deep Bed Biological Filtration of Drinking WaterSnider, Ryan Austin January 2011 (has links)
A series of pilot and full-scale experiments were carried out at the Mannheim Water Treatment Plant in Kitchener, Ontario to examine the impact of backwash technique, filter media characteristics, and combinations thereof on single stage drinking water biological filter performance. The media characteristics investigated were effective size, uniformity coefficient, and media type (GAC and anthracite). Backwash techniques investigated were the collapsed pulse backwash, the extended terminal subfluidization wash (ETSW), and the presence of chlorine in the wash water. Single stage biological filters must serve the dual purpose of biologically mediated removal of biodegradable organic matter (BOM), as well as meeting traditional filter performance criteria such as turbidity removal with minimal head loss accumulation. Accordingly, dissolved organic carbon removal, biodegradable dissolved organic carbon removal, biological respiration potential, turbidity removal, filter ripening time, and head loss accumulation were all quantified as measures of biological filtration performance. The results of this study have several implications for optimized design and operation of biological filters during drinking water treatment.
An increase in effective size of media grains from 1.0 mm to 1.3 mm was shown to significantly extend filter run time by minimizing head loss accumulation without compromising turbidity or BOM removal. Uniformity coefficient however, showed no significant effect on biological filter performance; indicating that the performance benefits associated with highly uniform media may not be commensurate with cost. GAC was found to be significantly more resilient to backwashing in collapsed pulse and chlorinated modes, which impaired BOM removal in anthracite filters. This resilience imparts a high degree of operational flexibility to backwashing GAC filters. The significant decrease in BOM removal by anthracite filters can be minimized; however, by using an optimized backwashing technique.
Collapsed pulse backwashing was found to have a significant effect on biological filter performance. When chlorinated collapsed pulse was used, filter cycles were significantly shortened by approximately 30 – 50% due to a sudden surge in effluent turbidity. This effect is thought to be the result of biofilm, damaged during the course of backwashing sloughing from the media. Extended terminal subfluidization wash was found to significantly reduce, and often eliminate filter ripening entirely. Additionally, the extended contact time with chlorine associated with chlorinated ETSW did not appear to have a significant effect on filter BOM removal. By eliminating filter ripening without compromising biological performance, ETSW shows promise for significant water and production cost savings by minimizing the filter-to-waste period during filter ripening. The presence of chlorine however, was associated with decreased DOC, 24 hours in to the filter cycle. This factor, combined with the negative interaction between chlorine and collapsed pulse suggests chlorinated wash water should be avoided in biological filtration systems like the ones investigated.
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The removal and recovery of oxo-anions from aqueous systems using nano-porous silica polyamine composites.Kailasam, Varadharajan. January 2009 (has links)
Thesis (PHD)--University of Montana, 2009. / Contents viewed on December 19, 2009. Title from author supplied metadata. Includes bibliographical references.
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Physicochemical aspects of particle breakthrough in granular media filtrationKim, Jinkeun, 1968- 02 August 2011 (has links)
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