Concentrations of As, Al, and other heavy metals (Cr¡BMn¡BFe¡BNi¡BCu¡BZn¡BGa¡BSe¡BSr¡BAg¡BCd¡BIn¡BSb¡BBa¡BHg¡BTl¡BPb¡BU) were measured in drinking waters in southern Taiwan. The analysis, using high resolution inductively coupled plasma mass spectrometry, indicated that concentrations of all elements were generally far below the maximum allowed concentration. The species of distribution of concentration were showed as follows (1) lower than 1£gg/L are Pb¡BTl¡BHg and Cd , (2) lower than 10£gg/L are Ni¡BGa¡BAs¡BSe¡BAg¡BIn¡BSb and U, (3) lower than 100£gg/L are Cr¡BCu¡BZn and Mn, (4) lower than 1000£gg/L are Al¡BFe¡BSr and Ba. Above results indicated that the concentrations of heavy meatals mostly are lower than Drinking Water Standard, except that Fe. The average removal index of advanced treatment process is 0.94 which is lower than 4.3 of conventional treatment process. It shows that the removal ability of advanced treatment process for heavy metals is higher than that of conventional treatment process. In addition Al¡BMn¡BFe¡BSr and Ba are the major heavy metals both in surface water and groundwater.

Thesis (M.S.) in Ecology and Environmental Sciences--University of Maine, 2002. / Includes vita. Includes bibliographical references (leaves 38-41).

Thesis (M. Sc.)--University of Hong Kong, 2002. / Includes bibliographical references (leaves 52-54).

Immunosuppressed persons such as HIV/AIDS patients are at risk of acquiring diarrhoeal infections from water-borne E. coli O157:H7. In the present study, we investigated the prevalence of E. coli O157:H7 in drinking water collected from selected distribution systems within the Amathole District of the Eastern Cape and its predicted impact on diarrhoeic conditions of HIV/AIDS persons living in this area. One hundred and eighty water samples and 360 stool swabs from confirmed and nonconfirmed HIV/AIDS diarrhoeic patients were analysed. Escherichia coli O157:H7 were isolated using enrichment culture and confirmed using molecular techniques. Of the 180 drinking water samples, 46 (25.56%) were positive for E. coli O157. The prevalence of E. coli O157 in the stools was at 36.39% (131/360) of which 56.5% (74/131) and 43.5% (57/131) were from stools of confirmed and non-confirmed HIV/AIDS patients, respectively. Molecular analysis of 27, 25 and 29 representative presumptive E. coli O157 from water and stools of confirmed and non-confirmed HIV/AIDS patients, respectively, revealed that 14.81%, 36% and 17.24% of the isolates were E. coli O157:H7. The findings predicted a possible link between E. coli O157:H7 isolated from drinking water and diarrhoeic conditions of both confirmed and non-confirmed HIV/AIDS patients visiting Frere Hospital for treatment.

Abstract A survey involving 181 water treatment plants across 7 provinces of South Africa: Mpumalanga, Limpopo, North West, Free State, KwaZulu-Natal, Eastern Cape and Western Cape was undertaken to identify the challenges facing small water treatment plants (SWTPs) in South Africa . Information gathered included ownership and design capacity of the plants, water sources, and various methods of disinfection, equipment currently employed and performance of the treatment plants. In general, the majority (over 80%) of the SWTPs surveyed in the designated provinces were owned by the district municipalities. The designed capacities of these plants varied between 1 and 60 Mℓ/d; the smallest capacity was 100 m3/d and the largest 120 Mℓ/d. The small water treatment plants abstracted their raw water from either surface or groundwater or a combination of both water sources with greater preponderance for surface water sources (over 86%). Water treatment practices were noted to be the conventional types mainly coagulation, flocculation, sedimentation, filtration and disinfection. Two types of coagulants namely polyelectrolyte (66%) and alum (18%) were commonly used by the water treatment plants across the provinces studied. Rapid gravity filtration, pressure filter and slow sand filtration systems accounted for 60%, 23% and 9% of the filtration systems across the provinces, respectively. The predominant types of disinfectants employed were chlorine gas (69%) followed by sodium (15%) and calcium (14%) hypochlorite. Over 50% of the various SWTPs did not comply with the SANS 241 Class I (< 1 NTU) and Class II (1 to 5 NTU) recommended turbidity values. The recommended target range of 0.3 to 0.6 mg/ℓ free chlorine residual concentrations at the point of use was not always met by 40% of the plants. Seventy percent of the SWTPs complied with the SANS 241 criteria of microbiological safety of drinking water vis-à-vis total and faecal coliforms. Operational problems affecting the efficiency of small water treatment plants included: inability to appropriately determine the flow rate, chemical dosage and turbidity, lack of chlorine residual at the point of use and lack of water quality monitoring. To produce safe drinking water, appropriate operational practices must be implemented in all small water treatment plants.

A model-based methodology for risk-based decision-making of water treatment and disinfection strategies that deal with the management of trihalomethanes (THMs) has been developed. Trihalomethanes (THMs) are by-products of chlorination for drinking water and have been characterized as possible and probable human carcinogens. Among THMs, bromodichloromethane (BDCM) has a much stronger association with stillbirths and neural tube defects than the other THMs species. The parameters affecting formation of THMs and BDCM were identified through multivariate statistical analysis of the Ontario Drinking Water Surveillance Program database and by reviewing publications. Formation of THMs is affected by chlorine dose, dissolved organic carbon, pH, temperature and reaction time; these parameters along with bromide ions have effects on brominated THMs formation in drinking water. Two models for predicting formation of THMs and BDCM in drinking water have been developed. Controlled experimental investigations were performed in laboratory following statistical design of the experiments using synthetic water samples. Using statistically significant parameters, models have been developed. The adequacies of the models were tested using appropriate statistical diagnostics and validation experiments. The models have been integrated into a risk-based decision making framework. Formation of THMs and BDCM were estimated by importing water quality and operational parameters into these models. The costs, technical feasibility and performances of different treatment and disinfection options were determined. Through the incorporation of multiple criteria (human health risk, cost, technical feasibility and disinfection performance), different treatment and disinfection strategies were evaluated and compared. A fuzzy logic stochastic approach has been utilized for the evaluation and tradeoff studies among different criteria. Overall, this thesis has continued to improve the environmental decision making process. The results of this thesis have provided a clearer understanding of parameters influencing THMs and BDCM formation in a complex environmental scenario. This thesis has presented a comprehensive approach to better control water quality and associated operational parameters through the use of predictive models and to perform decision making following a holistic approach. The results of this thesis will also assist in critical decision making for possible upgrading of water supply systems, analyzing uncertainty and complying with the regulatory limitations. / Thesis (Ph.D, Civil Engineering) -- Queen's University, 2009-02-10 14:41:03.975

Tap water collected according to standard methods was examined for microbial presence. Epifluorescent diagnoses using redox probe 5-cyano-2,3ditolyl tetrazolium chloride (CTC), 4',6-diamidino-2-phenylindole (DAPI), and acridine orange (AO) were employed for direct evidence of microorganisms. Evidence of total (DAPI or AO), respiring (CTC) bacteria, and heterotrophic plate count (HPC) was determined on multiple occasions during the summer, fall, and winter 1996-1997. Pseudomonas aeruginosa, Acinetobacter sp., Bacillus licheniformis, and Methylobacterium rhodinum were isolated and identified by the API and Biolog system using GN and GP procedures. On the basis of comparisons presented in this study between the CTC method and the standard HPC procedure, it appeared that the number of CTC-reducing bacteria in the tap water samples was typically higher than that determined by HPC, indicating that many respiring bacteria detected by the CTC reduction technique fail to produce visible colonieson the agar media used. In the seasonal data obtained by the CTC method, no difference was shown among respiring bacterial counts obtained from June through January. In the examination of P. aeruginosa viability in presence of chlorine, the number of CTC-positive bacteria exceeded the number of CFU by more than 2 logs after exposure to chlorine, suggesting that reliance on HPC overestimate the efficacy of disinfection treatment. In inactivation assays using the Biolog MT plate, no sensitivity to chlorine or chloramine disinfectants was noted even at high concentration levels (5 mg/liter). Following initial drop, bacterial activities increased as contact time increased. Thus, it appears that the MT microplate provides too low a cell concentration, too great a contact time, and/or too low a concentration of tetrazolium dye within the well for successful analysis of disinfectant capability to selected bacterial strains isolated from distribution water. / Department of Biology

This thesis presents work that focused on the customised detection and measurement of aluminium (Al) in labile and simple organic speciation in natural waters with particular reference to water treatment. The techniques developed were applied to several alum-based coagulation studies of water from the Myponga reservoir. Experiments examined total Al levels as well as the proportion of Al that was bound to natural organic matter (NOM). / The detection of Al was based upon the electrochemical determination of its complex with the ligand 1, 2-dihydroxyanthraquinone-3-sulphonic acid (DASA). The voltammetry of this complex allows the measurement of low levels of Al (LOD of 10 µg/L). This can be achieved by indirect analysis through oxidation by amperometry of DASA (+0.6V vs Ag/AgCl/KCl at a glassy carbon electrode) or by the reduction of the Al-DASA complex through adsorptive cathodic stripping voltammetry (-1.15V vs Ag/AgCl at a mercury film electrode). / An automated flow injection analysis (FIA-Al) manifold was developed based upon the above detection methods. The manifold utilised a number of switching valves, pumps and reactors under computer control. Reductive Al-DASA chemistry at the mercury film electrode to FIA-Al encountered a number of difficulties which prevented its application to real samples. Oxidative amperometry was successfully applied to probe Al levels during water treatment with coagulation. An instream low-level UV lamp, placed between switching valves, allowed Al speciation to be probed by preferentially irradiating different samples. Two Al fractions were thus determined, labile Al- the DASA reactive fraction without UV treatment, and total Al, the DASA reactive fraction processed semi-automatically with a high degree control of the key reaction conditions leading to good reproducibility. / The Al protocol developed was applied to different coagulation experiments with alum. In these experiments, standard and enhanced coagulation conditions were explored with both jar test apparatus and a coagulation/ flocculation pilot plant. This application of the FIA-Al process to the pilot plant allowed the Al levels in treated water to be determined on-line for a wide range of residual Al. / The application of organic matter characterisation techniques enabled further correlation between the Al speciation as derived by the FIA-Al procedure and the character of NOM that binds most readily with Al. Al speciation observed in this study follows the generalised trends observed in other more complex Al studies. During the treatment process, a proportion of Al exists as complex Al polynuclear species and as Al bound to NOM. After the precipitation/ sedimentation process has removed the majority of NOM and colloidal species, the majority of Al exists as the labile form that is free or bound to simple inorganic ions such as hydroxide, fluoride and sulphate. / Thesis ([PhDBiomedicalScience])--University of South Australia, 2004.

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. / Thesis (PhDAppliedScience)--University of South Australia, 2004.

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