Thesis, PlanB (M.S.)--University of Wisconsin--Stout, 2005. / Field problem. Includes bibliographical references.

No description available.

Thesis (PhD)--Montana State University--Bozeman, 2008. / Typescript. Chairperson, Graduate Committee: Anne Camper. Includes bibliographical references.

Nontuberculous mycobacteria (NTM) are ubiquitous in the environment and found in drinking water distribution systems and household plumbing. They are opportunistic pathogens of humans, causing lung disease. Their ability to adhere and form biofilm is attributed to a waxy, lipid-rich, cell envelope. This highly hydrophobic envelope also contributes to the characteristic antibiotic-, chlorine-, and disinfectant- resistance of NTM. NTM in household plumbing reside primarily in biofilms and the ability to form biofilm has been linked to virulence. Shedding of cells from biofilm and the subsequent aerosolization of microorganisms through showerheads presents a significant public health risk, particularly to those individuals with associated risk factors. Three species of NTM, Mycobacterium avium, Mycobacterium intracellulare, and Mycobacterium abscessus, were examined for adherence and biofilm formation on surfaces common to household plumbing systems, including glass, copper, stainless steel, polyvinyl chloride, and galvanized steel. All experiments were conducted with sterile, Blacksburg tap water in a CDC Biofilm Reactor. Highest adherence was observed by M. avium on galvanized steel surfaces, reaching 15,100 CFU/cm2 surface at 6 hours incubation at room temperature. After 3 weeks incubation at room temperature, biofilm formation of M. avium was also highest on galvanized steel surfaces, reaching 14,000,000 CFU/cm2 surface. Lowest adherence was observed by M. abscessus on polyvinyl chloride (PVC) surfaces, reaching 40 CFU/cm2. Lowest biofilm formation was observed by M. intracellulare on glass surfaces, reaching 5,900 CFU/cm2. Surfaces, such as galvanized (zinc), on which high adherence and biofilm formation was observed, should be avoided in household plumbing systems of NTM patients and individuals at risk for developing NTM disease. Additionally, surfaces such as copper, harbor fewer NTM and may provide a safer alternative for household plumbing of NTM patients. / Master of Science

This study analyzes and discusses the plumbing retailer from an individual point of view, just like a entrepreneur¡¦s point of view. The researcher focuses on the entrepreneur and adopts a life history point of view to interview the plumbing retailer. After that interview, the researcher can know the plumbing retailer¡¦s life history. Then the researcher analyzes his life history. Finally, the researcher discovers the important meaning to the plumbing retailer. The researcher has interviewed the plumbing retailer in depth for three times and has interviewed the others. Besides, the researcher has observed the business operation in the plumbing retailer¡¦s store for two weeks. According to the data, the researcher wrote the plumbing retailer¡¦s life story. Afterward the researcher has discussed the findings with my academic adviser for many times. The thesis statement has two parts as follows: The first part is the whole impression which is the pursuit of his economy. The second part has six major themes as follow: (1)undertaking the risk;(2)business vision;(3)keeping the work with great effort;(4)learning ability;(5)the role of the relations;(6)the position of the work and the family.

Thesis (M.F.A.)--Rochester Institute of Technology, 1990. / Typescript. Includes bibliographical references (leaves 38-39).

M.Ing. / With an ever-increasing population and a decrease in availability of fresh water, the sustainable and secure supply of fresh water is a growing concern worldwide, and particularly so in South Africa. Plumbing systems have a significant impact on both the efficient use of water and water losses because high quality plumbing components can reduce wastage and leakage, while inferior components increase the risk of failures and leakage and can even have health impacts in case of leaching of toxic elements or contamination of drinking water. In recent years, South Africa has seen a plethora of imported and pirated plumbing components introduced onto the local market. While South African legislation requires that only plumbing components approved by the South African Bureau of Standards or Water Services Authorities (municipalities) shall be installed, it does not explicitly prohibit the importation and sale of non-compliant components. The availability of non-compliant components on the market combined with insufficient enforcement of legislation, have created a situation where many non-compliant components are installed, although the extent of this problem was not known at the start of the project. The study aimed to quantify the extent of non-compliant plumbing components installed in South Africa, as well as the impact this will have on future water demands and losses. Various research methods were used including literature reviews, surveys and interviews with role players, search of available plumbing components for sale in South Africa, on-site visits and analysis of some case studies. The study found that about 50% of plumbing components installed in South Africa do not comply with legal requirements. Because these components are of poor quality, they hurt the local industry whose components cost more in order to comply with SABS standards. Therefore, they suffer from reduced market share and lower profit margins, and South African job losses occur in the sector. In general, compliant Summary components are up to 135% more expensive than non-compliant components. This study also found that even plumbers who are IOPSA members, and therefore bound by a code of conduct to use only compliant components, install non-compliant components. The site visits to some government low-cost housing developments showed that less than 10% of the plumbing components installed were compliant, and a major problem with non-compliant components was leakage. Therefore if the situation does not change, on-site water leaks will remain a great concern in South Africa. In order to address this situation the main suggestions are better enforcement of legislation, better training and control of plumbers and restrictions on the importation of non-compliant components.

Premise plumbing, the pipes and fixtures at the building level, present a unique challenge for maintaining drinking water quality. Of particular concern are opportunistic pathogens, including Legionella pneumophila which can regrow in premise plumbing and cause disease in immunocompromised populations. The goal of this work was to explore engineering methods for control of L. pneumophila and total regrowth. The first line of study involved a series of experiments with simulated glass water heaters (SGWHs) to investigate interactions between specific water chemistry factors and L. pneumophila regrowth, and the second used laboratory grade purified water to investigate the limits of a nutrient control approach for biological stability. Several water chemistry factors including assimilable organic carbon (AOC) content, granular activated carbon (GAC) biofiltration, plumbing materials, copper concentrations and temperature were investigated using SGWHs. AOC is the carbon available for bacteria growth in drinking water. Results indicated that AOC reduction may be a promising method for controlling L. pneumophila and total bacteria regrowth, but there may be a point at which AOC reduction is no longer effective. Prior GAC biofiltration removed organic carbon and was effective in controlling total bacterial regrowth in SGWHs, but actually encouraged L. pneumophila regrowth. A wide variety of materials typically encountered in premise plumbing was investigated and only had limited effect on proliferation of L. pneumophila and total bacteria. The effects were dynamic, even with long-term studies. Copper pipes held promise for control of L. pneumophila, as did copper concentration across a range of pHs. Aqueous copper concentration released from pipes was dependent on temperature, however, and thus this control method may not be applicable in all hot water lines. The peak temperatures for L. pneumophila proliferation fell between 41 and 45 °C, temperatures which could be encountered in a hot water distribution system when the water heater is set to 48 °C, as is often recommended with scalding and energy concerns. A constant temperature of 53 °C seemed to provide control of L. pneumophila, but recolonization is possible even at these high temperatures. Work with laboratory grade water indicated that extreme control of nutrients was not enough to completely control regrowth in premise plumbing. With stagnation in the cleanest conditions, a 2-log increase of a diverse group of bacteria was observed within 10 days. As drinking water can never achieve such nutrient removal, this study presents the limits of nutrient removal as a strategy for regrowth control. This work explored both the potential and the limitations of several mechanisms for controlling regrowth in premise plumbing. Understanding how these water chemistry factors affect L. pneumophila and total bacterial regrowth is critical to identifying the most effective engineering controls. / Master of Science

No description available.

Thesis (M. Hous. M.)--University of Hong Kong, 2007.