Thesis (Ph. D.) University of Missouri-Columbia, 2006. / The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on August 3, 2007) Includes bibliographical references.

Thesis (Ph. D.)--University of Texas at Austin, 2006. / Vita. Includes bibliographical references.

The study assessed the impact of the water supply intervention on the health-related microbiological water quality of source and stored water. The study area was a rural community with limited access to safe drinking water and sanitation systems for use. Previously, participating households had to collect water from remote sources (sub-villages near the river and irrigation canals), store water in various types of containers before use and under certain conditions in the domestic environment that may impact negatively on the water quality. These sub-villages were referred to as the Intervention group. The Reference group, were households from the same village (sub-villages away from the river) and for many years have collected and used water from communal taps. The water from the tap was pumped from a groundwater source of a better microbiological quality compared to the Intervention groups’ surface water. Communal standpipes that were installed several years ago were operationalised (water supply intervention) in the Intervention group at the time of the study and provided the opportunity to compare the various water sources and their impact on the health-related microbiological water quality of container-stored water. There were significant differences in the quality of various water sources used by the Intervention and Reference groups. The level of contamination was found to be higher in the Intervention group surface waters than in the Reference group tap water (groundwater source). Counts of total coliforms and E. coli were much higher in the Intervention group water sources than the Reference group, indicating that surface water was exposed to more pollution in the environment than the protected groundwater supplying taps. There were also significant differences in the water quality of source and container-stored waters used by both Intervention and Reference groups. The numbers of indicator organisms were significantly lower in the Intervention group container-stored river water than in the river source water, suggesting bacterial die-off in stored water. For the Reference group, higher counts of total coliforms and E. coli were found once tap water was sourced and stored in containers at home. The level of these indicators in the Reference group stored water supported the statement that water of good quality at the source often becomes contaminated during storage at home but in case of the Intervention group river water, the storage process brought about improvements in water quality. Container water quality of the Intervention group was assessed “before” and “after” the water supply intervention. A significant decrease was found in the indicator organism numbers (total coliforms and E. coli) “after” the intervention, showing a strong association between the use of an improved water supply and a good water quality. The results have also shown that the Reference group container-stored tap water had lower indicator organism numbers than the Intervention group container-stored river water before the intervention. After the Intervention group tap water was operationalised, its container-stored waters were compared to that of the Reference group (both groups now on tap water), and surprisingly there were significantly higher numbers of indicators in the Reference group stored water, suggesting poor domestic hygiene practices. No significant differences were expected because the same supply was used by both groups. Twenty eight households were randomly selected to assess the sustainability of the water supply intervention after one year of using tap water by the people of Folovhodwe, especially those from the Intervention group. There was a significant increase in the indicator organism numbers in container-stored water after one year of using tap water. Higher levels of indicator organisms (one year later) were probably associated with inadequate water handling practices at home, since the borehole groundwater after one year had zero indicator organisms (total coliforms and E. coli) indicating good water quality at the source. The health-related microbiological quality (at the source and in the containers) did not comply with the proposed safety limits in various water quality guidelines. A negative outcome in both groups was that E. coli was still higher than the WHO risk limit for water intended for drinking at the source and in storage containers suggesting continued faecal pollution of the water. Judging by the overall results, it is evident that the water supply intervention played a role in reducing the numbers of indicator organisms, although still above the guideline limits. It also appears that water supply interventions alone are not sufficient to improve and maintain water quality especially at the point of consumption; therefore hygiene practices around stored water at home need to be improved in order to achieve maximum health benefits. / Prof. P. Jagals Ms. B. Genthe

Mississippi has an abundant supply of underground aquifers which are utilized by community water systems as their source of drinking water. As the demand for water increases through the increasing population and the influx of industries, there is a need to manage the consumption and distribution of this valuable resource. Since its inception, the Mississippi drinking water industry has spawned new regulations, new management options, and creative ideas to promote a safer more efficient community water system. The Mississippi State Department of Health-Bureau of Public Water Supply’s Capacity Development Assessment is a comprehensive survey completed annually for every community water system in Mississippi. The Capacity Development Assessment will be used to gauge the quality of performance of the specified community water systems based exclusively on size classification, exclusively on government structure classification, and government structure by size classification. Over the past 15 years, Mississippi has seen several centralization efforts occur, where a municipality, utility district, and/or a rural water association merges with one or multiple adjoining or close proximity community water systems. This results in one of the three main legal structures of government over community water systems increasing in size in an effort to heighten performance. This research has analyzed the size (population) and government structures of Mississippi community water systems and has determined that economies of scale do exist. Government structure alone does not have an effect on the performance of community water systems but size alone does have an effect on the performance of community water systems. Municipalities and rural water associations reach optimal performance at the medium size classification and utility districts reach optimal performance at the small size classification. Regardless of the driving force, it is valuable to see that all of the Mississippi consolidating government structures are able to achieve optimal performance. Future state and/or federal legislatures, county governments, city governments, public water supply associations, and business economic drivers can benefit by knowing which structure(s) of community water system governance is the most productive and efficient when the time comes to explore the option of persuasion or mandates to increase viability or heighten performance.

Yes / The drinking water quality was investigated in suspected parts of Perak state, Malaysia, to ensure the continuous supply of clean and safe drinking water for the public health protection. In this regard, a detailed physical and chemical analysis of drinking water samples was carried out in different residential and commercial areas of the state. A number of parameters such as pH, turbidity, conductivity, total suspended solids (TSS), total dissolved solids (TDS), and heavy metals such as Cu, Zn, Mg, Fe, Cd, Pb, Cr, As, Hg, and Sn were analysed for each water sample collected during winter and summer periods. The obtained values of each parameter were compared with the standard values set by the World Health Organization (WHO) and local standards such as National Drinking Water Quality Standard (NDWQS). The values of each parameter were found to be within the safe limits set by the WHO and NDWQS. Overall, the water from all the locations was found to be safe as drinking water. However, it is also important to investigate other potential water contaminations such as chemicals and microbial and radiological materials for a longer period of time, including human body fluids, in order to assess the overall water quality of Perak state.

No description available.

Thesis (M. Heal. Sc.)--University of Canterbury, 2009. / Typescript (photocopy). Includes bibliographical references (leaves 85-88). Also available via the World Wide Web.

Thesis (PhD)--Stellenbosch University, 2004. / ENGLISH ABSTRACT: Microorganisms show a tendency to accumulate on surfaces in aqueous environments to form biofilms. Microbial biofilms represent a significant problem in public health microbiology as the development of these microbial communities, especially in water distribution systems, may lead to (i) the enhanced growth of opportunistic pathogens, (ii) the development of organoleptic problems, (iii) the reduction in the flow rate and (iv) the regrowth of microorganisms. In this project, biofilm monitors were installed in a large water distribution system to study biofilm phenomena in drinking water systems, and to deduce the biological stability and quality of the potable water. Measurements of biofilm formation potential showed that biofilms did not reach a steady state after 100 to 150 days. The microbial cells in these biofilms were mostly non-culturable. The contribution of the heterotrophic colony count to active biomass, as determined with cell numbers based on ATP measurements were often < 1%, while the ratio of heterotrophic plate counts and direct acridine orange counts were also <1%. The ratio between cell numbers based on ATP measurements and direct acridine orange counts were often < 100%. Results also showed that under certain conditions, such as those investigated in the present study, 1 pg of ATP may not be equal to approximately 104 active bacteria/cells, as stipulated by previous investigations, and that the average ATP content per active bacterial cell is indeed less than 10-16 - 10-15 g. It was calculated that threshold values for assimilable, and dissolved organic carbon below -5 IJg Gil and -0.5 mg Gil, respectively, should be target values for the control of biofilm formation in this system. It was shown that polyethylene, polyvinylchloride, teflon, plexiglass, copper, zinc-coated steel and aluminium provide favourable attachment surfaces that allowed primary colonisation and subsequent biofilm formation. Significant (p < 0.05) differences in surface colonisation on the materials were observed, indicating that the composition of the material has a direct influence on microbial colonisation. The two grades of stainless steel evaluated in this study were the least favourable materials for biofilm formation. It was further demonstrated that the nature of the surface of these materials, flow conditions and water type all had a direct influence on biofilm formation. While modification of the attachment surface did not result in significant differences (p > 0.05) in disinfection efficiency of two commonly used biocides, the concentration of the biocide, as well as the material to which the biofilm is attached, greatly influenced biocidal efficiency. The results show that biofilm monitoring needs to be implemented at the water treatment plants in addition to common biostability measurements. / AFRIKAANSE OPSOMMING: Mikro-organismes neig om te akkumuleer aan oppervlaktes in akwatiese omgewings om biofilms te vorm. Mikrobiese biofilms verteenwoordig In betekenisvolle probleem in publieke gesondheidsmikrobiologie omdat die ontwikkeling van hierdie mikrobiese gemeenskappe in waterverspreidingsisteme mag lei tot (i) die verhoogde groei van opportunistiese patogene, (ii) ontwikkeling van organoleptiese probleme, (iii) die vermindering in die vloeitempo en (iv) die hergroei van mikro-organismes. In hierdie projek was biofilm monitors geïnstalleer in In groot waterverspreidingsisteem om biofilm fenomene in drinkwatersisteme to bestudeer, en om die biologiese stabiliteit en kwaliteit van drinkwater af te lei. Bepalings van biofilmvormingspotensiaal het aangetoon dat biofilms nie In stabiele stadium na 100 tot 150 dae bereik nie. Die mikrobiese selle in hierdie biofilms was meestal niekweekbaar. Die bydrae van die heterotrofiese kolonie tellings tot aktiewe biomassa, soos bepaal deur seltellings gebaseer op ATP metings was dikwels < 1%, terwyl die verhouding van die heterotrofiese plaatteIIings en direkte akridien oranje tellings ook < 1% was. Die verhouding tussen seltellings, gebaseer op ATP metings en direkte akridien oranje tellings was dikwels < 100%. Resultate het ook aangetoon dat onder sekere omstandighede, soos dié wat ondersoek was in die huidige studie, 1 pg ATP nie gelyk is aan min of meer 104 aktiewe bakterieë/selle soos gestipuleer deur vorige ondersoeke nie, en dat die gemiddelde ATP inhoud per aktiewe bakteriële sel inderdaad minder as 10-16 tot 10-15 g is. Dit was bereken dat die drempelwaardes vir assimileerbare en opgeloste organiese koolstof onder -51-1g C/l en -0.5 mg C/l, onderskeidelik, teikens moet wees vir die beheer van biofilmvorming in hierdie sisteem. Dit was aangetoon dat polyetileen, polyvinielchlroried, teflon, plexiglas, koper, sink-bedekte staal en aluminium gunstige aanhegtings oppervlaktes voorsien wat primêre kolonisering en daaropvolgende biofilmvorming toelaat. Betekinisvolle (p <0.05) verskille in oppervlak kolinisering op die materiale was waargeneem, wat aandui dat die samestelling van die materiaal In direkte invloed op mikrobiese kolonisering het. Die twee tipes vlekvryestaal wat geëvalueer was in hierdie studie, was die minder gunstige materiale vir biofilmvorming. Dit was verder gedemonstreer dat die aard van die oppervlak van hierdie materiale, vloeitoestande, en water tipe almal In direkte invloed het op biofilmvorming. Terwyl die aanpassing van aanhegtingsoppervlak nie die ontsrnettinqsdoeltreffendheid resultaat van die twee algemeen-gebruikte biosiede betekinisvol (p > 0.05) beïnvloed het nie, het die konsentrasie van die biosiede doeltreffendheid grootliks beïnvloed. asook die aanhegtings-materiaal, biosied Die resultate het aangetoon dat biofilm monitering geïmplementeer moet word by waterbehandelingsaanlegte as In alternatief vir algemene biostabiliteit metings.

Thesis (M.S.)--University of North Carolina at Wilmington, 2003. / Includes bibliographical references (leaves : [65]-67).

Thesis (PhD)--University of South Australia, 2001.