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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Analysis of the recreational use of municipal water-supply areas

Moffat, Melvin G. January 1970 (has links)
A questionnaire survey of municipal water-supply agencies British Columbia, Washington, Oregon, and California was conducted for the purpose of comparing present management policies within and among the regions. Regression techniques were employed in an attempt to determine what factors influence the intensity of recreation occurring on a reservoir or watershed. A search of available literature was made to establish the 'facts' regarding water contamination through recreational use, the transmission of disease through water supplies, and the treatment of water to eliminate bacteria and viruses. The costs involved in the use or non-use of domestic water-supply areas for recreation were examined as were the major arguments for and against recreational use of these areas. The analysis of the questionnaire returns showed that in comparison with British Columbia, the States of Washington, Oregon and California all exhibited a higher level of water-supply management. Secondary uses were most prevalent in California and all of the respondents classifying themselves as 'secondary-use' agencies included recreation as one of the uses. In contrast to the situation in Washington and Oregon, and especially in British Columbia, recreational use in California was primarily a regulated use and very often planned and managed in detailed fashion with strict controls. The regression and correlation analysis showed some statistically significant but very weak relationships. The equations produced accounted for very little of the variation in the dependent variable (recreational-use score) and had very large standard errors of estimate. For the systems analyzed, the intensity of recreation occurring on a reservoir or watershed was related to such agency characteristics as present population served, percentage domestic use, degree of water treatment, average percentage of municipally or agency managed lands, average percentages of forest and shrub covered buffer and watershed lands and recreation opportunity in surrounding areas. From the search of pertinent literature and the questionnaire results, it was established that well planned and managed recreation facilities can be operated in conjunction with domestic water-supply facilities and have minimal effects on raw water quality. The potential hazard of disease transmission through the water system was fully recognized; however, water treatment techniques that will reduce this risk to a minimum are presently, available. On the basis of the research carried out in this study it was concluded that when conducted in accord with an ecologically sound management plan, recreation and the production of high quality potable water are indeed mutually compatible land uses. / Forestry, Faculty of / Graduate
2

Effects of holding tank odor control chemicals on aerobic wastewater treatment

McDaniel, Charles Russell 08 September 2012 (has links)
Three odor control chemicals and formaldehyde were tested for detrimental affects on activated sludge using bench-scale bioreactors. Slug fed and continuous flow bioreactors were monitored for changes in suspended solids, specific oxygen uptake rate, sludge settling and compaction, and effluent COD. The biodegradability of dyes and the generation of foam was also measured. Formaldehyde and the formaldehyde-based odor control chemical "Aqua-Kem" damaged the ability of activated sludge to treat wastewater. They resulted in deceased suspended solids concentrations and increased effluent COD. Formaldehyde hinders the utilization of normal wastewater substrate by activated sludge. The dye in "Aqua-Kem" is not biodegradable, and surfactants in the chemical generate foam. / Master of Science
3

Investigation of the presence and change over time of water quality parameters in selected natural swimming areas in Oregon

Van Ess, Erica 02 May 1997 (has links)
Few studies, and none in Oregon, have examined the presence and change of water quality parameters over time in popular natural swimming areas. This information is necessary to better understand water quality and risk of illness from either fecal contamination or cross-infection from other swimmers. The purpose of this study was to quantitatively measure bacterial and selected physical and chemical parameters, and collect background information for changes to the current state water quality criteria. Five natural swimming areas in Linn, Benton and Polk counties were chosen and sampled biweekly for physical, chemical, and bacterial parameters over a nine week period from June 28 to August 31, 1996. The results showed differences in bacterial levels over the sampling period which often varied by degrees of magnitude between sites. For example, the range in Escherichia coli levels was between 0 and 1000 colonies/100mL sample for two sites on the same sampling day. Similarly, the range in fecal coliform levels was between 5 and 500 colonies/100mL sample. The daily colony counts at each site exceeded the state standards at least 10% of the time for E. coli and 21% of the time for fecal coliform. At the most popular swimming site, Montieth Park. the fecal coliform regulatory levels were exceeded 79% of the time and E. coli levels were exceeded 42% of the time. This may be due to turbidity, high bather load, or a broken sewer line. The 30 day log mean of these values shows consistently elevated fecal coliform problems only at Montieth Park. For the other sites, the log means did not exceed the state and federal regulatory limits for fecal coliform or E. coll. This raises questions about which estimates should be used to assess public health risk. None of the other parameters in this study were correlated with bacterial counts, so it appears that none of these factors is solely responsible for elevated bacterial levels. Further testing should be done at Montieth Park to determine the cause of the elevated fecal coliform levels. Any follow-up studies should test several different indicator organisms in addition to E. coli for comparison and assessment of their relationship to public health risk. / Graduation date: 1997

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