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This doctoral dissertation examines the holistic health and wellbeing of a First Nation community to understand several factors relating to environmental racism and water contamination that support and hinder community health and wellbeing to inform future policy. This dissertation incorporates a mix of methodological approaches across three interrelated research studies to better understand the direct and indirect factors influencing water security and community health and wellbeing. Study 1 consists of a theoretical approach to co-creating knowledge between Indigenous collaborators and medical anthropologists. It highlights the importance of community-based participatory research in medical anthropology and frames the co-creation of a health survey through three phases as a boundary object that can create dialogical space for Indigenous and settler-scholar pedagogies and priorities. It demonstrates how CBPR and co-creation work allows for the reciprocal development of long-term partnerships that work in solidarity with the Two-Row Wampum (Kaswentha) treaty established by the Haudenosaunee Nation and European settler nations. Study 2 presents an analysis of household water access, quality, and use, specifically how E. coli and mercury contaminations of household tap water are related to reported household health conditions for a sample of 66 households (representing 226 individuals) living in Six Nations First Nation. Logistic regression models were built to identify possible associations with water use and treatment variables for mental health, eczema, and gastroenteritis, with a second model adding contaminants as predictor variables. In the second model, E. coli was found to be a significant predictor for the presence of mental health conditions within the household, and households primarily purchasing bulk bottled water were more likely to report mental health conditions. Those using bleach/chlorine to treat their tap water were more likely to report gastroenteritis. Reported tap water uses indicated that 57% of contaminated tap water was still being used for activities that may heighten exposure risks (such as washing produce). Investigating household tap water uses beyond drinking water demonstrates alternative pathways for contaminant exposures for Six Nations Peoples, who have deep cultural relationships with water. Study 3 contains a mixed methods approach to investigate the effects of water access, satisfaction, and experiences of water insecurity for the sample of 66 households in Six Nations of the Grand River First Nations, to inform culturally effective ways of assessing water insecurity for Indigenous Nations experiencing long term water shortages, contamination, and other water- related concerns. Water security was measured using the Household Water InSecurity Experiences (HWISE) scale and Likert-scale questions on water access at household, community, service, and environmental levels, and contextualized using interviews. Results demonstrate a high level of water insecurity in the sample of Six Nations households (57.5%, n=38); women were more dissatisfied with their drinking water (p=0.005), and younger participants were more likely to report contamination issues (p=0.02) and higher monthly water costs (p=0.03). Qualitative interviews informed these results, revealing that experiences of water insecurity and poor health were shaped by the degradation of traditional lands. This posed specific barriers for Six Nations women, who face physical and geographical barriers to household and community water access while caretaking for their communities and fulfilling their roles as water protectors. / Thesis / Doctor of Philosophy (PhD) / The goal of this doctoral dissertation was to explore the connections between water security and health with Six Nations of the Grand River First Nation, to explore the nuanced factors that inform perceptions of drinking water and better understand who in the community faces higher challenges and barriers throughout the water crisis. This project was co-created research using Indigenous Knowledge (IK) with medical anthropology approaches to understand water security, satisfaction, quality, and relationships as they relate to Haudenosaunee health. Water security was explored through tap and well water contamination tests, survey data, and interviews and focus groups. Water insecurity was reported for 57.5% of 66 households in this sample, with 21.2% having E. coli contamination in their tap water, 25.4% having mercury in their tap water exceeding provincial drinking water limits, and 77% of households relying primarily on bottled drinking water rather than their tap water. While water insecurity experiences were quite high in this study, Western metrics are not able to capture the crucial elements of Indigenous water relationships, such as community and cultural relationships with the land, environmental racism, and the consequences of environmental degradation, such as grief or poor mental health, relating to water and climate crisis. Water insecurity experiences are best understood as highly localized experiences that have mental health, physical health, and environmental consequences for Indigenous communities. To fully untangle the specific cultural, spiritual, racial, and colonial landscapes or structures that have shaped Six Nations experiences and perceptions of their local water, co-created and flexible place- based methodologies are needed.

The objectives of this research were to develop a broad spectrum method for the extraction, concentration, and analysis of drinking water disinfection by products using solid phase extraction (SPE), and to determine if this method had lower detection limits and less variability than the proposed liquid-liquid extraction method, EPA Method 551. The disinfection by products investigated were halogenated nitriles, ketones, and aldehydes. The SPE method extracted and concentrated samples using the C-18 Empore Extraction Disks, and desorbed the analytes with methyl-tert-butyl ether (MTBE) as a solvent. The results showed that with the SPE method the recoveries were low (0-50%) for most compounds, and the limit of detection (LOD) values were in the range of 0.2 to 50 ug/L, which were much higher than those for EPA Method 551. The variability was also higher than for EPA Method 551. The SPE method also appeared to be concentration dependent; the recoveries decreased as analyte concentration increased. Highly saline conditions (250 g/L NaCl) resulted in low recoveries and concentration dependencies for some compounds. Even though the SPE method was easier and faster, the lower method detection limit (MDL) values and lower variability made Method 551 more preferable. Further analysis of the SPE method using a new cyclohexyl disk was also recommended. / Master of Science

Orientador: Anna Silvia Palcheco Peixoto / Co-orientador: Emília Carlos Prandi / Banca: Rodrigo Lilla Manzione / Banca: Ilza Machado Kaiser / Resumo: A crescente demanda por recursos subterrâneos nas Bacias Hidrográficas dos Rios Aguapaí e Peixe, localizadas no oeste do Estado de São Paulo e a presença cada vez maior de substâncias em condições de acesso e contaminação das águas em subsuperfície têm pressionado de forma negativa a disponibilidade hídrica nessas bacias. Neste contexto de degradação, esta Dissertação objetiva a caracterização e avaliação da vulnerabilidade natural e dos perigos de contanimação das unidades aquíferas aflorantes nas subunidades de gestão de recursos hídricos denominados Alto Aguapeí e Alto Peixe. A caracterização da Vulnerabilidade foi realizada com aplicação do método GOD (Foster & Hirata, 1988). O perigo de contaminação dos aquíferos foi avaliado mediante a interpolação da vulnerabilidade natural com as fontes potencias de contaminação, identificadas e classificadas quanto o seu potencial de gerar carga contaminante, a partir da aplicação do método POSH (FOSTER et al, 2006). Os procedimentos de geoprocessamento foram realizados com auxílio do SIG ArcMap TM 9.3. Os resultados demonstraram que vulnerabilidades de classificação Extrema estão restritas as planícies fluviais dos rios Aguapeí e Tibiriça, ocupando cerca de 2% da área de estudos, as classes de vulnerabilidade Alta e Alta Baixa ocupam 41,5% e 23,7% respectivamente, enquanto 28,4% da área correspondem à vulnerabilidade Média. Para o restante da área obteve-se a classificação Média e Média Baixa Vulnerabilidade. A correlação das vulnerabilidades com as fontes potenciais de contaminação demonstraram que independente da localização, os postos de combustível e os locais de disposição de resíduos sólidos apresentam Alto perigo de contaminação. As atividades da indústria, por sua vez, apresentam Alto perigo de contaminação para os distritos... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The increasing demand for groundwater resources in the Watersheds of Aguapeí and Peixe Rivers, located in the western part of São Paulo province, and also the increasing presence of substances in access condition and water contamination in the subsurface have been pressuring negatively the water availability in both basins. In this degradation context, this dissertation aims to characterize and evaluate the natural vulnerability and contamination risks of aquifers outcropping units in the sub water resources management units called. Alto Aguapeí and Alto Peixe. The vulnerability characterization was made applying the GOD method (Foster & Hirata, 1988). The aquifers contamination risk was estimated by interpolation of the natural vulnerability and the potential contamination sources that was identified and classified by their potential to generate contaminant load, using the POSH method (Foster et al, 2006). The geoprocessing producers were performed with assisting of some tools from the GLS ArcMap TM 9.3. The results evidenced that extreme classification vulnerability are restricted just for river plaints of Aguapeí and Tibiriça rivers, occupying around 2% of the studied area. The High and High Low vulnerability classes occupy 41.5% and 23.7% respectively and average vulnerability 28.4%. For the rest of the area was obtained medium and low vulnerability classification. The correlation of vulnerabilities and potential sources of contamination demonstrated that regardless of location, gas stations and solid waste disposal spots have high risks of contamination. The industrial activities have a high risk of contamination due the industrial district of Garça and Marilia and moderate for units in the food sector, located outside these districts. Furthermore, it is evident the importance of introducing the territory management policies... (Complete abstract click electronic access below) / Mestre

Made available in DSpace on 2017-07-10T17:36:55Z (GMT). No. of bitstreams: 1 2014_Diss_Juliana_Casarin.pdf: 3962661 bytes, checksum: a0e8bf7ab504aff06792e47bb73244a0 (MD5) Previous issue date: 2014-02-21 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The present work proposes the use of the bark of Bertholletia excelsa HBK, a residue of the beneficiation of Brazil nut, as biossorvente in removal of metal ions toxic cadmium (Cd), lead (Pb), chromium (Cr), copper (Cu) and zinc (Zn) of contaminated water, as an alternative to conventional methods of available treatments. The characterization of biosorbent was performed by scanning electron microscopy (SEM), infrared spectroscopy (IR) and the point of zero charge (pHPCZ). After that, adsorption tests were performed aiming to determine the ideal conditions of pH, mass of adsorbent and contact time for the adsorption process. The adsorption kinetics was evaluated by the models of pseudo first model, pseudo second order, Elovich and intraparticle diffusion. From the obtained results, isotherms of adsorption were built for each metal, which were linearized as mathematical models of Langmuir, Freundlich and Dubinin-Radushkevich. To compare the natural adsorbents with a commercial adsorbent were performed comparative studies with the activated coal. In addition, we evaluated the ability of desorption of the materials and the influence of temperature on adsorption process of metals under study by bark of B. excelsa HBK. The characterization of biosorbent through SEM showed a roughness surface, showing important characteristics of adsorption. From the FT-IR was possible identify compounds such as lignin and cellulose, which favour the adsorption process. The pHPCZ obtained was 4.1. The tests of mass demonstrated that 12 g L-1 of biossorvente are sufficient for an effective removal of metal ions Cd, Pb and Cr in solution, and 8 g L-1 for the ions Cu and Zn. With respect to the pH values of the solution, there was no difference among them, being that the higher removed quantity obtained at pH 5.0. The time for dynamic equilibrium was found at 60 minutes. The application of kinetic models suggests the limiting factor for the adsorption of these metal ions may be the chemisorption. The equilibrium isotherms were obtained based on pre-established optimal conditions for each metal and the mathematical adjustments were performed by mathematical models of Langmuir, Freundlich and Dubinin-Radushkevich (D-R). The mathematical models that best adjusted for adsorption in bark of Brazil nut was Dubinin-Radushkevich for Cr and Cu, Freundlich and Langmuir for Cr for all the ions studied, and thus estimate the parameter maximum capacity of adsorption (Qm) provided by this model, being Cr = 12.69; Pb = 10.77; Cd = 7.45, Zn = 4.86 and Cu = 3.92 mg g-1. The negative value for variation of free energy (ΔG) obtained by means of thermodynamic studies for adsorption of metals Cd, Cr, Cu and Zn is an indication of a spontaneous process and favorable, in the case of Pb2+, the values of ΔG reported that there was no absorption of energy for the formation of products, so that the reaction is not spontaneous. The results showed that the biosorbent from bark of Brazil nut may constitute a sustainable alternative for low cost, by not having suffered prior treatment and because it is a dried grape byproduct in removal of metal ions present in waters / O presente trabalho propõe a utilização da casca de Bertholletia excelsa HBK, um resíduo do beneficiamento da castanha do Brasil, como biossorvente na remoção dos íons metálicos cádmio (Cd), chumbo (Pb), cromo (Cr), cobre (Cu) e zinco (Zn) de águas contaminadas, como alternativa aos métodos convencionais de tratamento existentes. Assim, após a caracterização do biossorvente por meio de microscopia eletrônica de varredura (MEV), espectroscopia na região do infravermelho (IV) e ponto de carga zero (pHPCZ), foram realizados testes de adsorção objetivando determinar as condições ideais de pH, massa de adsorvente e tempo de contato para o processo de adsorção. A cinética de adsorção foi avaliada pelos modelos de pseudoprimeira ordem, pseudossegunda ordem, Elovich e difusão intrapartícula. A partir dos resultados obtidos, foram construídas as isotermas de adsorção para cada metal, as quais foram linearizadas conforme os modelos matemáticos de Langmuir, Freundlich e Dubinin-Radusckevich. Visando comparar este biossorvente com um adsorvente comercial, foram realizados estudos comparativos com o carvão ativado. Além disso, foram avaliados a capacidade de eluição dos materiais e a influência da temperatura no processo de adsorção dos metais em estudo pela casca de B. excelsa HBK. A caracterização do biossorvente por meio da MEV mostrou uma superfície rugosa, importantes características de adsorção. A partir do espectro de IV foi possível identificar compostos como a lignina e celulose, os quais favorecem o processo de adsorção. O pHPCZ obtido foi de 4,4. Os testes de massa demonstraram que 12 g L-1 do biossorvente são suficientes para uma remoção eficiente dos íons metálicos Cd, Pb e Cr em solução, e de 8 g L-1 para os íons Cu e Zn. Com relação aos valores de pH da solução, não houve diferença entre eles, sendo que testes futuros foram desenvolvidos em condição de pH 5,0. O tempo para que o sistema atingisse o equilíbrio entre os metais estudados foi 60 min. O modelo cinético de pseudoprimeira ordem foi o que melhor se ajustou ao processo cinético, sugerindo desta forma que o principal passo limitante para a adsorção destes íons metálicos pode ser a adsorção química. As isotermas de equilíbrio foram obtidas com base nas condições ótimas pré-estabelecidas para cada metal e os ajustes matemáticos foram realizados por meio dos modelos matemáticos de Langmuir, Freundlich e Dubinin-Radushkevich (D-R). Os modelos matemáticos que melhor se ajustaram para a adsorção em casca de castanha do Brasil foram Dubinin-Radushkevich para o Cr e Cu, Freundlich para Cr e Langmuir para todos os íons estudados, podendo assim estimar o parâmetro capacidade máxima de adsorção (Qm) fornecido por este modelo, sendo Cr = 12,69 > Pb = 10,77 > Cd = 7,45, Zn = 4,86 e Cu = 3,92 mg g-1. O valor negativo de variação de energia livre (ΔG) obtido por meio dos estudos termodinâmicos para a adsorção dos metais Cd, Cr, Zn e Cu é uma indicação de um processo espontâneo e favorável, no caso do Pb2+, os valores de ΔG demostraram que a reação não é espontânea. Os resultados mostraram que o biossorvente proveniente da casca de castanha do Brasil pode constituir uma alternativa sustentável de baixo custo, por não ter sofrido tratamento prévio e por se tratar de um coproduto na remoção dos íons metálicos presentes em águas

Thesis (MPH)--University of Limpopo, 2005 / Water and sanitation inadequacy is still an environmental health challenge in several regions worldwide and a billion people lack access to safe water, while 2.4 billion people have inadequate sanitation [2]. Assessment of water quality by its chemistry includes measures of elements and molecules dissolved or suspended in water. Commonly measured chemical parameters include arsenic, cadmium, calcium, chloride, fluoride, total hardness, nitrate, and potassium [16]. Water quality can also be assessed by the presence of waterborne microorganisms from human and animals’ faecal wastes. These wastes contain a wide range of bacteria, viruses and protozoa that may be washed into drinking water supplies [21]. Three villages were selected for water quality analysis, based on their critical situation regarding access to water and sanitation: namely, Matlou, Sekuruwe and Taolome villages, situated in the Mogalakwena Local Municipality within the Waterberg district of the Limpopo Province, South Africa. A proposal was written to the Province of North Holland (PNH) and was approved for funding to start with the implementation of those projects, with 20% of each village’s budget allocated for water quality research [26]. This was a cross sectional, analytical study to investigate the chemical and microbial quality of water in Matlou, Sekuruwe and Taolome villages. The study was also conducted to explore methods used by household members to store and handle water in storage tanks. Water samples were collected and analysed according to the standard operating procedures (SOPs) of the Polokwane Municipality Wastewater Purification Plant in Ladanna, Polokwane City of South Africa. The questionnaire used was adopted from the one used for cholera outbreak in the Eastern Cape Province of South Africa. Results show that water from all sources in all the villages had increased total hardness concentration. Water from the borehole in Matlou village had increased number of total coliform bacteria. There were increased total and faecal coliform bacteria in storage tanks samples from Matlou village. Water samples from reservoirs in Sekuruwe and Taolome villages did not test positive for any microbial contamination. Water from xiv informally connected yard taps in Sekuruwe village had increased total coliform bacteria, while increased total and faecal coliforms were found in households’ storage tanks. Water samples from communal taps in Taolome village had minimal number of total coliform bacteria, while water from storage tanks had both increased total and faecal coliform bacteria. Matlou village was the only place with increased nitrate concentration at the households’ storage tanks. While all the villages had microbial contamination, Taolome village had the least number of coliform bacteria in water samples from households’ storage tanks as compared to Matlou and Sekuruwe villages. It is concluded that water from sources supplied by the municipalities are safe to be consumed by humans while water from informally connected taps and households’ storage tanks are not safe to be used without treatment. It is recommended that a health and hygiene education package be prepared for all the villages, so that handling of water from the main source into their storage tanks can be improved. Secondly, it is recommended that water in all sources be treated for total hardness and water in storage tanks in Matlou village be treated for nitrate. Thirdly, it is recommended that water be accessed everyday of the week, so that people do not use unsafe water supplies. / The Province of North Holland, Netherlands.

Groundwater contamination by landfill generated leachate is a problem that is increasingly addressed for proposed and existing landfill sites.This thesis examines groundwater contamination movement from the abandoned Delaware County Municipal landfill. The site is located in the crest of a highly permeable sand and gravel glacial esker which allows for rapid movement of ground water and any contaminants introduced into it.The landfill site was originally investigated in the late 1970's by Ed Lusch, a graduate student at the Ball State University Geology Department. That study showed some indications of ground water contamination movement to about 400 feet west of the site, in the direction of ground water flow. This indicated position of a contamination plume suggested that leachate, generated from the landfill site, had moved to that position since (or possibly before) the closing of the landfill in 1971.The present study, using a combination of surface resistivity methods, on-site test wells, and chemical analyses of ground water, attempted to determine the degree of contamination movement from the site since the original study and the extent to which the local aquifer had been affected. Results of this investigation revealed an apparent slow movement of leachate from the landfill westward towards the Mississinewa River, also in the direction of ground water flow. Surface resistivity methods of this study revealed the plume of contamination (indicated by resistivity "low" area) to now exist at approximately the same location as indicated in the earlier study, but to have expanded laterally. This investigation also found indications of the contamination plume well into the underlying fractured dolostone.Chemical analyses of nearby residential wells also revealed slightly elevated amounts of chloride, ammonia and specific conductivity in the ground water of the glacial esker south of the abandoned landfill site. The presence of three other dump sites, including a sludge dump, along the esker south of the landfill, offers questions as to the source of ground water contamination.Ball State UniversityMuncie, IN 47306

Irradiation with ultraviolet (UV) light is used for the disinfection of bacterial contaminants in the production of potable water, and in the treatment of selected wastewaters. However, efficacy of UV disinfection is limited by the combined effect of suspended solids concentration and UV absorbance. Limited published UV disinfection data are available that account for the combined effects of UV dose, suspended solids concentration and UV absorbance. This present lack of a rigorous quantitative understanding of the kinetics of UV disinfection limits process optimisation and wider application of UV treatment. The development and validation of an adequate model to describe UV disinfection kinetics presented in this thesis can therefore be justified by an increased confidence of reliability of design for UV disinfection. Using the published data of Nguyen (1999), four established model forms were assessed to account for the combined effect of suspended solids and/or soluble UV absorbing compounds, and UV dose on the efficacy of disinfection. The four model forms were: a log-linear form, Davey Linear-Arrhenius (DL-A), Square-Root (or Ratkowsky- Belehradek) and a general nth order Polynomial (nOP) form that was limited to a third order. Criteria for assessment of an adequate predictive model were established including: accuracy of predicted against observed values, percent variance accounted for (%V), and; appraisal of residuals. The DL-A model was shown to best fit the data for UV disinfection of Escherichia coli (ATCC 25922); followed by the nOP, log-linear and Square-Root forms. However, the DL-A form must be used in conjunction with a first-order chemical reaction equation, and was shown to predict poorly at high experimental values of UV dose (> 40,000 μWs cm-2). The DL-A model was not amenable to extrapolation beyond the observed UV dose range. To overcome the shortcomings of the Davey Linear-Arrhenius model synthesis of two new, non-linear model forms was undertaken. The two models were a modified exponentially damped polynomial (EDPm) and a form based on the Weibull probability distribution. The EDPm model has three terms: a rate coefficient (k), a damping coefficient (λ), and; a breakpoint dose ([dose]B). The rate coefficient governs the initial rate of disinfection prior to the onset of tailing, whilst the breakpoint is the UV dose that indicates the onset of tailing. The damping coefficient controls curvature in the survivor curve. The Weibull model has just two terms: a dimensionless scale parameter (β0), and; a shape parameter (β1). The scale parameter represents the level of disinfection in the tail of the survivor curve (as log10 N/N0), whilst the shape parameter governs the degree of curvature of the survivor data. Each model was assessed against the independent and published UV disinfection data of Nelson (2000) for treatment of faecal coliforms in a range of waste stabilisation pond effluents. Both models were found to be well suited to account for tailing in these UV disinfection data. Overall, the EDPm model gave a better fit to the data than the Weibull model form. To rigorously validate the suitability of the new EDPm and Weibull models a series of experimental trials were designed and carried out in a small-scale pilot UV disinfection unit. These trials included data determined specifically at low values of UV dose (<10,000 μWs cm-2) to fill the gap in the experimental data of Nguyen (1999). The experimental trials were carried out using a commercially available, UV disinfection unit (LC5TM from Ultraviolet Technology of Australasia Pty Ltd). Purified water contaminated with Escherichia coli (ATCC 25922) with a range of feed water flow rates (1 to 4 L min-1) was used. E. coli was selected because it is found in sewage, or water contaminated with faecal material, and is used as an indicator for the presence of enteric pathogens. E. coli should not be present in potable water. The hydrodynamics of water flow within the disinfection unit were established using digital video photography of dye trace studies with Methylene Blue. Nominal UV dose (2,700 to 44,200 μWs cm-2) was controlled by manipulating the flow rate of feed water through the UV disinfection unit (i.e. residence time), or by varying the exposed length of the control volume of the disinfection unit. The transmittance of the feed water (at 254 nm) was adjusted by the addition of either a soluble UV absorbing agent (International RoastTM instant coffee powder; 0.001 to 0.07 g L-1), or by addition of suspended matter as diatomaceous earth (Celite 503TM; 0.1 to 0.7 g L-1, with a median particle size of 23 μm). The absorbing agent (instant coffee), when in a comparable concentration, was found to produce a greater reduction in water transmission than the suspended material (Celite 503TM). It therefore contributed to a greater reduction in the initial rate of disinfection. Neither agent was found to produce a systematic reduction in the observed efficacy of disinfection however. Experimental results highlight that in the absence of soluble absorbing agents, or suspended solids, the initial rate of disinfection is higher when fewer viable bacteria are initially present. Both the new EDPm and Weibull forms gave a good fit to the experimental data. The EDPm better fitted the data on the basis of residual sum-of-squares (0.03 to 2.13 for EDPm cf. 0.16 to 4.37 for the Weibull form). These models are both of a form suitable for practical use in modelling UV disinfection data. Results of this research highlight the impact of water quality, as influenced by the combined effect of UV dose, suspended solids concentration and UV absorbance, on small-scale UV disinfection for potable water production. Importantly, results show that the concentration of soluble UV absorbing agents and suspended solids are not in themselves sufficient criteria on which to base assessment of efficacy of UV disinfection / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1342403 / Thesis (M.Eng.Sc.) - University of Adelaide, School of Chemical Engineering, 2008

Irradiation with ultraviolet (UV) light is used for the disinfection of bacterial contaminants in the production of potable water, and in the treatment of selected wastewaters. However, efficacy of UV disinfection is limited by the combined effect of suspended solids concentration and UV absorbance. Limited published UV disinfection data are available that account for the combined effects of UV dose, suspended solids concentration and UV absorbance. This present lack of a rigorous quantitative understanding of the kinetics of UV disinfection limits process optimisation and wider application of UV treatment. The development and validation of an adequate model to describe UV disinfection kinetics presented in this thesis can therefore be justified by an increased confidence of reliability of design for UV disinfection. Using the published data of Nguyen (1999), four established model forms were assessed to account for the combined effect of suspended solids and/or soluble UV absorbing compounds, and UV dose on the efficacy of disinfection. The four model forms were: a log-linear form, Davey Linear-Arrhenius (DL-A), Square-Root (or Ratkowsky- Belehradek) and a general nth order Polynomial (nOP) form that was limited to a third order. Criteria for assessment of an adequate predictive model were established including: accuracy of predicted against observed values, percent variance accounted for (%V), and; appraisal of residuals. The DL-A model was shown to best fit the data for UV disinfection of Escherichia coli (ATCC 25922); followed by the nOP, log-linear and Square-Root forms. However, the DL-A form must be used in conjunction with a first-order chemical reaction equation, and was shown to predict poorly at high experimental values of UV dose (> 40,000 μWs cm-2). The DL-A model was not amenable to extrapolation beyond the observed UV dose range. To overcome the shortcomings of the Davey Linear-Arrhenius model synthesis of two new, non-linear model forms was undertaken. The two models were a modified exponentially damped polynomial (EDPm) and a form based on the Weibull probability distribution. The EDPm model has three terms: a rate coefficient (k), a damping coefficient (λ), and; a breakpoint dose ([dose]B). The rate coefficient governs the initial rate of disinfection prior to the onset of tailing, whilst the breakpoint is the UV dose that indicates the onset of tailing. The damping coefficient controls curvature in the survivor curve. The Weibull model has just two terms: a dimensionless scale parameter (β0), and; a shape parameter (β1). The scale parameter represents the level of disinfection in the tail of the survivor curve (as log10 N/N0), whilst the shape parameter governs the degree of curvature of the survivor data. Each model was assessed against the independent and published UV disinfection data of Nelson (2000) for treatment of faecal coliforms in a range of waste stabilisation pond effluents. Both models were found to be well suited to account for tailing in these UV disinfection data. Overall, the EDPm model gave a better fit to the data than the Weibull model form. To rigorously validate the suitability of the new EDPm and Weibull models a series of experimental trials were designed and carried out in a small-scale pilot UV disinfection unit. These trials included data determined specifically at low values of UV dose (<10,000 μWs cm-2) to fill the gap in the experimental data of Nguyen (1999). The experimental trials were carried out using a commercially available, UV disinfection unit (LC5TM from Ultraviolet Technology of Australasia Pty Ltd). Purified water contaminated with Escherichia coli (ATCC 25922) with a range of feed water flow rates (1 to 4 L min-1) was used. E. coli was selected because it is found in sewage, or water contaminated with faecal material, and is used as an indicator for the presence of enteric pathogens. E. coli should not be present in potable water. The hydrodynamics of water flow within the disinfection unit were established using digital video photography of dye trace studies with Methylene Blue. Nominal UV dose (2,700 to 44,200 μWs cm-2) was controlled by manipulating the flow rate of feed water through the UV disinfection unit (i.e. residence time), or by varying the exposed length of the control volume of the disinfection unit. The transmittance of the feed water (at 254 nm) was adjusted by the addition of either a soluble UV absorbing agent (International RoastTM instant coffee powder; 0.001 to 0.07 g L-1), or by addition of suspended matter as diatomaceous earth (Celite 503TM; 0.1 to 0.7 g L-1, with a median particle size of 23 μm). The absorbing agent (instant coffee), when in a comparable concentration, was found to produce a greater reduction in water transmission than the suspended material (Celite 503TM). It therefore contributed to a greater reduction in the initial rate of disinfection. Neither agent was found to produce a systematic reduction in the observed efficacy of disinfection however. Experimental results highlight that in the absence of soluble absorbing agents, or suspended solids, the initial rate of disinfection is higher when fewer viable bacteria are initially present. Both the new EDPm and Weibull forms gave a good fit to the experimental data. The EDPm better fitted the data on the basis of residual sum-of-squares (0.03 to 2.13 for EDPm cf. 0.16 to 4.37 for the Weibull form). These models are both of a form suitable for practical use in modelling UV disinfection data. Results of this research highlight the impact of water quality, as influenced by the combined effect of UV dose, suspended solids concentration and UV absorbance, on small-scale UV disinfection for potable water production. Importantly, results show that the concentration of soluble UV absorbing agents and suspended solids are not in themselves sufficient criteria on which to base assessment of efficacy of UV disinfection / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1342403 / Thesis (M.Eng.Sc.) - University of Adelaide, School of Chemical Engineering, 2008

Irradiation with ultraviolet (UV) light is used for the disinfection of bacterial contaminants in the production of potable water, and in the treatment of selected wastewaters. However, efficacy of UV disinfection is limited by the combined effect of suspended solids concentration and UV absorbance. Limited published UV disinfection data are available that account for the combined effects of UV dose, suspended solids concentration and UV absorbance. This present lack of a rigorous quantitative understanding of the kinetics of UV disinfection limits process optimisation and wider application of UV treatment. The development and validation of an adequate model to describe UV disinfection kinetics presented in this thesis can therefore be justified by an increased confidence of reliability of design for UV disinfection. Using the published data of Nguyen (1999), four established model forms were assessed to account for the combined effect of suspended solids and/or soluble UV absorbing compounds, and UV dose on the efficacy of disinfection. The four model forms were: a log-linear form, Davey Linear-Arrhenius (DL-A), Square-Root (or Ratkowsky- Belehradek) and a general nth order Polynomial (nOP) form that was limited to a third order. Criteria for assessment of an adequate predictive model were established including: accuracy of predicted against observed values, percent variance accounted for (%V), and; appraisal of residuals. The DL-A model was shown to best fit the data for UV disinfection of Escherichia coli (ATCC 25922); followed by the nOP, log-linear and Square-Root forms. However, the DL-A form must be used in conjunction with a first-order chemical reaction equation, and was shown to predict poorly at high experimental values of UV dose (> 40,000 μWs cm-2). The DL-A model was not amenable to extrapolation beyond the observed UV dose range. To overcome the shortcomings of the Davey Linear-Arrhenius model synthesis of two new, non-linear model forms was undertaken. The two models were a modified exponentially damped polynomial (EDPm) and a form based on the Weibull probability distribution. The EDPm model has three terms: a rate coefficient (k), a damping coefficient (λ), and; a breakpoint dose ([dose]B). The rate coefficient governs the initial rate of disinfection prior to the onset of tailing, whilst the breakpoint is the UV dose that indicates the onset of tailing. The damping coefficient controls curvature in the survivor curve. The Weibull model has just two terms: a dimensionless scale parameter (β0), and; a shape parameter (β1). The scale parameter represents the level of disinfection in the tail of the survivor curve (as log10 N/N0), whilst the shape parameter governs the degree of curvature of the survivor data. Each model was assessed against the independent and published UV disinfection data of Nelson (2000) for treatment of faecal coliforms in a range of waste stabilisation pond effluents. Both models were found to be well suited to account for tailing in these UV disinfection data. Overall, the EDPm model gave a better fit to the data than the Weibull model form. To rigorously validate the suitability of the new EDPm and Weibull models a series of experimental trials were designed and carried out in a small-scale pilot UV disinfection unit. These trials included data determined specifically at low values of UV dose (<10,000 μWs cm-2) to fill the gap in the experimental data of Nguyen (1999). The experimental trials were carried out using a commercially available, UV disinfection unit (LC5TM from Ultraviolet Technology of Australasia Pty Ltd). Purified water contaminated with Escherichia coli (ATCC 25922) with a range of feed water flow rates (1 to 4 L min-1) was used. E. coli was selected because it is found in sewage, or water contaminated with faecal material, and is used as an indicator for the presence of enteric pathogens. E. coli should not be present in potable water. The hydrodynamics of water flow within the disinfection unit were established using digital video photography of dye trace studies with Methylene Blue. Nominal UV dose (2,700 to 44,200 μWs cm-2) was controlled by manipulating the flow rate of feed water through the UV disinfection unit (i.e. residence time), or by varying the exposed length of the control volume of the disinfection unit. The transmittance of the feed water (at 254 nm) was adjusted by the addition of either a soluble UV absorbing agent (International RoastTM instant coffee powder; 0.001 to 0.07 g L-1), or by addition of suspended matter as diatomaceous earth (Celite 503TM; 0.1 to 0.7 g L-1, with a median particle size of 23 μm). The absorbing agent (instant coffee), when in a comparable concentration, was found to produce a greater reduction in water transmission than the suspended material (Celite 503TM). It therefore contributed to a greater reduction in the initial rate of disinfection. Neither agent was found to produce a systematic reduction in the observed efficacy of disinfection however. Experimental results highlight that in the absence of soluble absorbing agents, or suspended solids, the initial rate of disinfection is higher when fewer viable bacteria are initially present. Both the new EDPm and Weibull forms gave a good fit to the experimental data. The EDPm better fitted the data on the basis of residual sum-of-squares (0.03 to 2.13 for EDPm cf. 0.16 to 4.37 for the Weibull form). These models are both of a form suitable for practical use in modelling UV disinfection data. Results of this research highlight the impact of water quality, as influenced by the combined effect of UV dose, suspended solids concentration and UV absorbance, on small-scale UV disinfection for potable water production. Importantly, results show that the concentration of soluble UV absorbing agents and suspended solids are not in themselves sufficient criteria on which to base assessment of efficacy of UV disinfection / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1342403 / Thesis (M.Eng.Sc.) - University of Adelaide, School of Chemical Engineering, 2008