The Nigerian Drinking Water Supply and Distribution Sector

The United States Environmental Protection Agency recently issued a new MaximumContaminant Level (MCL) for arsenic in drinking water. The new MCL lowers theacceptable level of arsenic in drinking water from 50 parts per billion to 10 parts perbillion. Treatment technologies for arsenic removal are expensive to operate.Nontreatment options pose an alternative to treatment. Nontreatment is allowed undergovernment regulation. However, such options are limited by local hydrogeologicconditions. Many areas in Arizona have favorable conditions. Estimates for the capitalcosts for several nontreatment options were collected through surveys. In a comparison ofthe capital costs of nontreatment options to treatment, nontreatment was less than half thecost of treatment. Operating costs for nontreatment are also expected to be several timessmaller than for treatment. A comparison using annualized costs shows that nontreatmentcosts less than one fifth of treatment.

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The purpose of this research was to improve understanding of the quality of drinking water for domestic consumption in the City of Kumul, China. The guidelines for drinking water testing in the City of Kumul were assessed and compared with actual practices. Local households in the urban center were interviewed in order to assess public attitudes towards drinking water. The results showed that the quality of treated water did not pose a direct threat to human consumers, but there were opportunities for improvements in the areas of source water protection, water treatment processes, and communication between authorities and the public. 74% of urban households personally treated their tap water prior to consumption, most commonly by boiling, to improve drinking water quality. It is recommended that the local government should seek to improve communication between the water treatment authority and the public to ensure water quality in the City of Kumul.

The aim of this study was to analyse the interaction of natural organic matter (NOM) with the disinfectant ozone and the influence these interactions have on bromate formation and the production of assimilable organic carbon (AOC) in Australian drinking waters. / In order to achieve this, four local source waters (Hope Valley Reservoir, Myponga Reservoir and Warren Reservoir and Lake Wallace) were selected based on the variability of their raw water characteristics. Ozonation experiments on all four waters revealed that, even at low ozone / DOC ratios, bromate formed in levels above current regulatory guideline values. Previously developed bromate formation prediction models based on (overseas) raw water quality characteristics were assessed and found generally not to be applicable to the prediction of bromate in Australian drinking waters. / The NOM from two of these raw waters (Myponga and Lake Wallace) was first concentrated via reverse osmosis and then fractionated according to molecular weight (using ultrafiltration) and character (using ion exchange resins). This resulted in the production of eight distinct isolates derived from each source water. Analysis of the structural makeup of each fraction by techniques such as ¹³C-NMR, UV spectroscopy and HPSEC revealed significant differences in character and structure of each NOM isolate. / Ozonation of these fractions under identical conditions showed that the amount of bromate formed was dependent on the individual fraction and, more importantly, on the structural characteristics of that particular isolate. Kinetic studies revealed an apparent relationship between ozone decomposition and the formation of bromate. Analysis of these data using the previously developed "bromate yield" concept revealed the existence of a bromate formation threshold value for each NOM isolate, ozone being consumed readily upon addition to the sample before bromate begins to form. Once the ozone threshold has been met, bromate (per unit of consumed ozone) forms at a rate dependent on the characteristics of each fraction. Analysis using the "ozone exposure" concept confirmed this trend. / Research into the dominant mechanism of bromate formation revealed that the response of each fraction was dependent on whether the formation mechanism was dominated by direct oxidation (via the molecular ozone mechanism) or indirect oxidation (via the hydroxyl radical mechanism). / A study of 30 randomly selected bottled waters for disinfection by-products (DBPs) found that bromate was present in 12, with all being above guideline levels, some significantly so, posing a possible health concern. THMs were detected in 18 samples but in all cases were present at low concentrations. / An investigation into the influence each NOM isolate has on the formation of assimilable organic carbon (AOC) through the analysis of bacterial regrowth potential (BRP) values revealed that certain fractions may be contributing more to the BRP of the raw water and that the effects are dependent on the character of the NOM in the water. If the more biodegradable fractions can be preferentially removed after ozonation, problems caused by the formation of ozonation by-products will be reduced. / Thesis ([PhDAppliedScience])--University of South Australia, 2004.

Title page, contents and abstract only. The complete thesis in print form is available from the University of Adelaide Library. / The aim of this study was to describe the potential impact of stratification, and therefore destratification, and inflow hydrodynamics on the raw water quality in drinking water reservoirs, from the perspective of NOM. Investigations of the changes in the concentration, character and removal of NOM by conventional treatment processes during inflow hydrodynamics and thermal stratification were performed using observational and manipulative experiments and empirical and process based modelling. Further conceptual models were developed in place NOM within the existing frameworks of reservoir management from the perspective of other water quality hazards. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1321572 / Thesis (Ph.D.) -- University of Adelaide, School of Earth and Environmental Sciences, 2008

Title page, contents and abstract only. The complete thesis in print form is available from the University of Adelaide Library. / The aim of this study was to describe the potential impact of stratification, and therefore destratification, and inflow hydrodynamics on the raw water quality in drinking water reservoirs, from the perspective of NOM. Investigations of the changes in the concentration, character and removal of NOM by conventional treatment processes during inflow hydrodynamics and thermal stratification were performed using observational and manipulative experiments and empirical and process based modelling. Further conceptual models were developed in place NOM within the existing frameworks of reservoir management from the perspective of other water quality hazards. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1321572 / Thesis (Ph.D.) -- University of Adelaide, School of Earth and Environmental Sciences, 2008

The prevalence of the cyanobacterial metabolites: MIB, geosmin and microcystin in drinking water is a major concern to the water industry as these metabolites can compromise the quality of drinking water. Consequently, effective removal of these metabolites from drinking water is paramount. The combination of ozone (O3) and granular activated carbon (GAC) has been shown to be effective for the removal of these metabolites from drinking water. In this study, the ozonation of MIB and geosmin was affected by the character of natural organic material (NOM). In particular, NOM containing compounds of high UV absorbing properties and high molecular weight (MW) resulted in greater destruction of MIB and geosmin due to the formation of hydroxyl (OH) radicals. In addition, alkalinity also affected the ozonation process, with waters containing higher alkalinity resulting in decreased destruction of MIB and geosmin. Laboratory scale minicolumn experiments, coupled with the homogenous surface diffusion model (HSDM), were found to be ineffective in predicting the GAC breakthrough behaviour of MIB and microcystin at two different pilot plants. This can be attributed to the biological degradation of the metabolites at the pilot plants which cannot be modelled by the HSDM. In addition, the volume of GAC used in the minicolumn experiments may not have been appropriate for the predictions, rather, larger laboratory scale columns were found to be more applicable in mimicking pilot plant results. Microcystins were shown to be readily degraded by the bacteria attached to the GAC. Furthermore, the lag period prior to the onset of degradation, which is indicative of most biological degradation studies, was effectively eliminated and in one instance abated. This finding suggests that biological filtration of microcystin is practically feasible especially since the occurrence of microcystins in water supplies is seasonal. This study expands on previous research in the area of O3 and GAC for the treatment of MIB, geosmin and microcystin. With the imminent increase of the use of O3 and GAC in Australian water treatment plants (WTPs), this study provides valuable information for the use of these processes both alone and in combination, particularly since minimal research in this area has been conducted in Australia. / thesis (PhDAppliedScience)--University of South Australia, 2004.

Thesis (Ph. D.)--University of Missouri-Columbia, 2007. / 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 March 6, 2008) Includes bibliographical references.

Thesis (M.S. - Microbiology and Immunology)--University of Arizona, 1985. / Includes bibliographical references (leaves 54-59).