Thesis (M.S. - Hydrology and Water Resources) - University of Arizona. / Includes bibliographical references (leaves 46-47).

Thesis (M.S.)--Ohio University, March, 1992. / Title from PDF t.p.

Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1992. / Vita. Abstract. Includes bibliographical references (leaves 109-112). Also available via the Internet.

Thesis (PHD)--University of Montana, 2010. / Contents viewed on April 9, 2010. Title from author supplied metadata. Includes bibliographical references.

Thesis (M.S.)--University of Michigan, 1981.

M.Sc. / The Vaal Dam (South Africa) and its tributaries have been extensively affected by domestic, mining, agricultural and industrial activities, as well as the release of effluents. These practices have contributed to large-scale algal blooms that have caused serious ecological, aesthetic, water purification and water distribution problems. This study addresses the need to develop a system that enables forecasts to be made regarding potential changes in the water quality ofthe Vaal Dam, especially with regards to predicting algal blooms. The primary aim was to develop a simple spreadsheet based model to predict the occurrence of algal blooms and other water quality changes in the Vaal Dam, making use of environmental parameters recorded at several sites located upstream of the Rand Water intake point at the Vaal Dam wall. Accurately forecasting sudden changes in water quality would enable proactive resource management, ensuring that Rand Water maintains a high standard of potable water delivered to its customers. Statistical model equations, to predict the concentrations of various water quality constituents, were obtained by step-wise regression analysis. These equations were then entered into MS-Excel spreadsheets. This allowed the input of environmental data and the subsequent calculation of the predicted value. This also allowed for the manipulation of various parameters to forecast the effects any changing values will have on the water quality. These "if-then'' scenarios would be of considerable use in implementing management measures to achieve the desired water quality. The performance of the model was statistically tested to determine if it adequately represents the study system. The models to determine chlorophyll-a concentration and several other water quality constituents proved to be fairly accurate in representing the study system. However, the model to predict nitrate concentrations did not perform satisfactorily. The limitations in model performance were attributed to the low frequency of water quality sampling and the effects of undetermined variables not represented by the water quality parameters selected for model development. The model is compact, does not require specialised software, and is applicable in practice. The predictive and scenario forecasting abilities make this model useful for the identification, monitoring and prediction of changes or trends in water quality over time. The benefits arising from this model will thus contribute to more cost efficient water treatment, improved response times to algal blooms, improved decision-making and proactive water resource management.

M. Tech. / The study assessed the risk of infection introduced by containers in which households collect water from different sources. The study area was in rural villages in the Vhembe region of the Limpopo Province. Each village had its own unique water sources consisting mainly of untreated ground waters and untreated surface waters. Randomly selected household members use their containers to collect water from these different sources. Two of the three villages received new small water supply systems within the study period, proving the villagers with water of good health-related microbial quality. The remaining village continued to use contaminated water from their untreated surface water sources. The water supply intervention in two of the three villages provided the opportunity to assess the impact these interventions would have on the risk of infection i.e. whether the risk could be reduced for the villagers no having access to good quality water. A customized quantitative microbial risk assessment was done based on the health-related quality of the water that people ingested before and after the intervention. This assessment was based on exposure of, consequence to and impact on an individual water consumer. Exposure included variables such as daily quantities of unheated drinking water consumed per individual (in litres) available at the point of use (in the dwelling) for ingestion, numbers of diarrhoeagenic E. coli (Dec) per litre in water sampled from containers derived from water samples positive for indicator E. coli and daily doses of DEc per litre ingested by an individual in the target population. Consequence was assessed by calculating the probability of infection per day from diarrhoeagenic E. coli for an individual and from there the annual infection per individual. The impact of the small water supply system was determined by assessing changes in annual individual risk of infection from before to after the interventions per village. In terms of daily water volumes consumed per individual, there were no significant differences in consumption amongst the three villages. At 1.26 ℓcd (at the upper limit of the 95% confidence interval) the consumption was slightly higher than the one litre suggested by WHO 2003. The container water collected from sources before the intervention in the two villages was significantly more contaminated by indicator E. coli (iEc) and diarrhoeagenic E. coli (DEc) than their container waters after the intervention. In terms of impact, the risk of infections was substantially reduced by the interventions. For Village 1 the risk of infection was reduced from 646 infections to 135 infections per 10,000 of the population. If these are converted to 10% as disease manifesting, then there could have been 65 cases of enteric disease attributable to water before the intervention, which was then reduced to 14 cases after the intervention. For Village 2 the population risk was reduced from 110 to 67 cases after the intervention. For Village 3 the population risk remained at 2,778 infections or 278 cases of enteric waterborne disease because of their continued use of untreated water. The study findings indicated that for Village 1, the population risk of infection would be 135 infections per 10,000, for Village 2 it would be 167 and for Village 3 - 234. If the hypothetical conversion rate of one case of enteric waterborne disease for every 10 infections of Howard et al. (2006) is used, then this would mean 14 cases of disease per 10,000 for the population for Village 1, 17 cases for Village 2 and 24 cases for Village 3. Relating this to the WHO (2003) suggestion of one case per 1,000 as an acceptable, it would mean 1.3 cases for Village 1, 1.7 for Village 2 and 2.4 for Village 3. For Village 1 the risk of contracting waterborne enteric disease was close to acceptable, but not at all acceptable for the other two villages, even for Village group 2 after the intervention. The water system in Village 2 failed often during the study which was probably the cause of the persistently higher risk of disease. It can be concluded that providing a well maintained small water supply system reduced the risk to and maintained it at an acceptable level. Table

A research Report submitted to the Faculty of Science, University of the Witwatersrand, Johannesburg, in partial fulfillment of the requirements for the degree of Master of Science, 2018 / Cyanobacteria cells enter water treatment plants from the raw water abstracted from surface water destined to supply the water treatment plants. The presence of cells might interfere with purification processes such as coagulation and flocculation and may subsequently result in the release of taste and odourous compounds. This study is aimed at determining the efficiency of a Recovered Wash Water Plant (RWWP), in removing cyanobacteria cells and associated organic compounds at three stages of treatment, namely raw water, after sedimentation and after filtration. Concentration outcomes were statistically analysed to determine removal ability of the RWWP. The cyanobacteria genera Microcystis, Anabaena and Oscillatoria were detected in the three sampling points (raw water, after sedimentation and after filtration) selected. The organic compounds detected included geosmin, 2-methylisoborneol (2-MIB), and a cyanotoxin, microcystin. It is recommended that the effectiveness of the RWWP should be investigated seasonally during further research / MT 2020

Thesis (M. Sc.)--University of Hong Kong, 1999. / Includes bibliographical references (leaves 138-145).

Thesis (M.E.S.)--Evergreen State College, 2009. / "June, 2009." Title from title screen (viewed 4/8/2010). Includes bibliographical references (leaves 48-54).