No description available.

It is common knowledge that water is one of the basic needs for human beings. However, the consumption of contaminated water can lead to waterborne diseases and fatalities. It is, therefore imperative to constantly monitor the quality of potable water. There are numerous technologies used for water quality monitoring. These technologies are relatively effective however these tests are expensive and complex to use, which then require experienced technicians to operate them. Other tests are not rapid, making consumers of water susceptible to waterborne diseases. In this study, dye-doped, surface functionalized silica nanoparticles (SiNPs) and surface-functionalized magnetic nanocomposites (MNCs) were proposed as materials that can be applied in order to reduce the time taken to get results as well as to make the processes less complex and portable. The aim of this study was to synthesize and characterize surface functionalized dye-doped SiNPs and surface functionalized MNCs for detection and preconcentration of in water. Additionally, proof of concept had to be shown using the synthesized materials. SiNPs were the materials of choice due to their easily functionalized surfaces and their strong optical properties. SiNPs are photostable and they do not leach in solution due to the inert nature of the silica matrix in aqueous media. MNCs were chosen as materials of choice for preconcentration of E. coli in water because they are easy to synthesize and they can be applied in various biological applications due to their functional groups. SiNPs were synthesized using the water-in-oil microemulsion. The SiNPs were further functionalized with amine and carboxyl groups and avidin. Thereafter, they were bioconjugated with biotinylated anti-E. coli antibodies. The pure and surface functionalized SiNPs were characterized using ATR-FTIR spectroscopy, FE-SEM, HR-TEM, Zeta Sizer, UV-vis spectroscopy and spectrofluorometry. The application of the dye—doped surface functionalized SiNPs in E. coli detection was characterized using the fluorescence plate reader. The SiNPs were spherical and uniform in size. They increased in size as they were being functionalized, ranging from 21.20 nm to 75.06 nm. The SiNPs were successfully functionalized with amine and carboxyl groups as well as with avidin and antibodies. Two methods were investigated for carboxyl group attachment (direct and indirect attachment) and the direct attachment method yielded the best results with a surface charge of -31.9 mV compared to -23.3 mV of the indirect method. The dye loading was found to be 1% after particle synthesis. The optical properties of the Ru(Bpy) dye were enhanced 3 fold when they were encapsulated in the Si matrix. The SiNPs were binding to the E. coli cells and enabled detection. MNCs were synthesized through in-situ polymerization. The MNCs were characterized using ATR-FTIR spectroscopy, SEM, TEM and XRD. The MNCs were successfully functionalized with carboxyl groups. The increase in size of the nanocomposites as seen in SEM images proved that the Fe3O4 was successfully encapsulated in the polymer matrix. The MNCs were proven to be magnetic by a simple magnetism test whereby they were separated in an aqueous solution using an external magnetic field. The antibody-labelled MNCs were binding to the E. coli cells as shown in TEM images. E. coli cells were removed from water at varying concentrations of 1x106 CFU/mL to 1x109 CFU/mL at 10 mL volumes. This study has demonstrated that dye-doped SiNPs amplify the signal of E. coli cells using fluorescence. The study has also demonstrated that the MNCs can be applied in sample preconcentration and enrichment for E. coli detection. However, further studies should investigate and optimize the combination of the two techniques in a point of use device for water quality testing of 100 mL-samples as per the requirement of the SANS 241 standard. / Civil and Chemical Engineering / M. Tech. (Chemical Engineering)

Thesis submitted in fulfilment of the requirements for the degree Magister Technologiae: Chemical Engineering in the Faculty of Engineering at the Cape Peninsula University of Technology 2014 / An awareness campaign on the harmful effects of Perfluorinated compounds (PFCs), especially Perfluorooctanoic acid (PFOA) and Perfluorooctane sulfonate (PFOS) has been conducted to inform the general public about the impact of these organic compounds on hu-mans and biota. These compounds have been shown to be potential carcinogens, as indi-cated by the United States Environmental Protection Agency (USEPA) and the Organization for Economic Co-operation and Development . A major concern about these chemicals is that they have been widely used in consumer products and have been detected in food and drinking water. They have been determined to be resistant to biological degradation, owing to their unique chemical and physical properties (fluorine atoms that have substituted hydrogen atoms in their chemical structure). Owing to their characteristics of being highly soluble in water, they cannot be removed from water using ordinary purification processes. Studies have been conducted to evaluate the removal of PFOA and PFOS from water using different methods. Among these methods, it has been proved that adsorption is a suitable method with the best adsorbent identified as activated carbon (AC). AC can be found in many forms, including as a fibre. The use of AC for the removal of PCFs can be augmented with sonica-tion and electro-chemical methods for rapid absorption of these compounds. The aim of this study was to remove these contaminants using a microporous AC fibre (ACF) made from an indigenous plant, Agave sisalana, which is widely available across sub-Saharan Africa, by using electro-physico-chemical methods. ACF has the following advantages when compared with granulated and/or powdered AC: it has a slightly larger reactive surface area; small quantities can be used; it is easily handled; it retains its shape under stress, thus does not require additional filtration to remove particulate residue; and can be regenerated easily. The manufacturing process of the ACF was done in several steps: 1) harvesting of the A. sisalana leaves, stripping them to obtain wet fibre by scrapping using traditional meth-ods, 2) chemical activation using NaOH, KOH, ZnCl2 and H3PO4, employing a spraying method instead of soaking, which was followed by drying, and 3) carbonisation in a furnace at the required temperature. The use of activation reagents involved the determination of an appropriate concentration, with optimum concentrations determined as 0.54M, 0.625M, 1.59M and 0.73M for NaOH, KOH, ZnCl2 and H3PO4, respectively. Apart from the fibre acti-vation, temperature and activation time were also important parameters that were optimised. A response surface methodology was used to design a set of experiments that provided the optimum temperature and activation time. From the input variables, the Expert design soft- ware generated experimental runs (n = 13) for each fibre activation reagent used with a tem-perature range of 450°C to 933°C being assessed for carbonisation time of between 17 to 208 minutes. ACF activated with KOH (0.54 M) and characterised by micropores with the highest surface area achieved being 1285.8 m2/g in comparison with Granular activated car-bon (Ounas et al., 2009) with an average surface area range of 1000 to 1100 m2/g. This sur-face area was measured using Dubinin-Astakhov isotherm with CO2 at 273 K. The physical characteristics of the ACF were analysed using a Scanning Electron Microscope to ascertain the integrity of the fibres. PFOA and PFOS were analysed using a solid phase extraction (SPE) method fol-lowed by analysis using a liquid chromatography/tandem mass spectrometer (SPE-LC/MS/MS). The water sample volume used for extraction was 60 mL. The instrument used was an HPLC - Ultimate 3000 Dionex HPLC system and MS model - Amazon SL Ion Trap, with the following MS/MS operational conditions and ion mode: MS Interface → ESI; dry temp → 350C; nebulising pressure → 60 psi; dry gas flow → 10 L/min; ionisation mode → negative; capillary voltage → +4500V; end plate offset → −500V, while the separation col-umn was a Waters Sunfire C18, 5 μm, 4.6 × 150 mm column (supplier: Waters, Dublin, Ire-land), with an operational temperature of 30C. Initially, adsorption studies (n = 48) using sonication (20 kHz) in batch systems indi-cated efficient removal of PFOA and PFOS within 120 min, with numerous samples (n = 14) achieving complete removal for both PFOA and PFOS. The minimum removal rates ob-served were 65.55% for PFOA and 95.92% for PFOS. From the ACF samples in which high-est removal rates were achieved, a number (n = 3) of the ACF samples were selected for surface characterisation. Based on the sonication in the previous experiments, an electro-physico-chemical adsorption regime was designed, to facilitate the rapid adsorption of PFOS and PFOA from contaminated drinking water in an electrolytic cell. In these experiments, si-multaneous sonication and electrolysis were used. A comparison was made between ACF produced in this study and the commercial activated carbon. The result revealed that adsorp-tion of PFOA and PFOS on ACF was a monolayer adsorption type phenomenon and had the best fit using a Freundlich isotherm compared with the Langmuir isotherm. Adsorption of PFOA and PFOS on the commercial AC presented a multilayer adsorption type of isotherm fit with the Langmuir isotherm having the best fit compared with the Freundlich isotherm.

Thesis (Diploma (Civil Engineering))--Cape Technikon, 1986. / In rural areas in Southern Africa a nearby stream or spring is a village or kraal 's main water supply. The majority of these elementdry water sources are polluted. In this project the health hazard of polluted water and methods to protect water sources from pollution are discussed. The project consists of a report of fieldwork done in Southern Kwazula and compiling from the results a Technical Paper on water source protection.

Water quality is concerning as many still lack access to safe drinking water. Alternate sources such as rivers (FC up to 1600 CFUs/100 mL) and rainwater are often polluted. Rainwater tanks require maintenance to improve water quality, but could be used for non-potable purposes or irrigation. Grahamstown infrastructural failures initiate deviations from DWAF 1996 domestic water guidelines for microorganisms within the distribution system. Frequent testing can decrease risks of waterborne diseases. Limitations to this are inaccessibility of rural areas, distances from testing centres and costs. The low cost H2S strip test able to be used onsite by communities, may aid in risk assessment. H2S strip test results are not affected by sulphate (14 to 4240 mg/L) or nitrite (up to 47 mg/L). Transportation of the H2S strip tests between 10 and 32°C does not modify results significantly. Similarly to other studies: Klebsiella spp.; Enterobacter spp. and Serratia spp. were isolated from H2S strip tests. The mH2S strip test corresponds best with HPC in treated water, while in untreated river water it has approximately 90% correspondence with FCs, while survival of FC causes discrepancies with the H2S test after 22 days. A faecal coliform inactivation rate of 0.1 CFUs/ day, may be longer than many pathogens. Faecal source tracking, not currently practised in South Africa, could aid health risk assessments for disaster management, which would improve the NMMP programme. Bacterial survival times could propose the time period for which water is unsafe. Bifidobacteria and Rhodococcus are proposed to help identify the faecal pollution source. But enumeration of Rhodococcus is too lengthy (21 days). The tracking ratio of bifidobacteria (between 0.1 to 6.25) is not source definitive. The bifidobacteria survival rate, could indicator the time since faecal pollution. The bifidobacteria average survival rate is 2.3 CFUs per day for both groups. The culturability and selectivity of agar is still poor, with total bifidobacteria less selectively culturable. Enterococci overgrowth of TB was decreased by Beerens media. SUB is still useful to identify potential human faecal inputs. A single tracking method is thus not suitable alone, but requires a combination of techniques.

M.Tech. (Biomedical Technology) / Drinking water in the greater Johannesburg area is produced by Rand Water and is transported to local Johannesburg Water where it is stored in reservoirs for distribution. At any point during the production, distribution and storage of the water, contamination with free-living amoebae, potentially containing amoeba resistant bacteria, may occur. Free-living amoebae are often resistant to the biocides used by water treatment industries and may thus be transmitted to public facilities, consumers’ homes and informal settlements through water distribution systems and during storage in small containers. The aim of our study was to analyse the water quality around Johannesburg with regard to free-living amoebae and amoeba resistant bacteria. A total of 182 tap and 5 storage tank water samples, collected from Hillbrow, Bertrams, Riverlea, Braamfischerville and Hospital Hill, were analysed for amoebae, indicator organisms, Legionellae, environmental mycobacteria, Shigella, Salmonella and Vibrio species using amoebal enrichment method. Direct microscopy indicated the presence of amoebae in 96.1% of samples. Acanthamoeba cysts were present in 69.0% of the samples. In 55.0% of these samples visibly active intracellular bacteria were observed within the sample suspensions. In the 46 samples analysed by polymerase chain reaction, the presence of Acanthamoeba species was confirmed in 65.2%, and the intracellular bacteria such as Legionella pneumophila and Mycobacterium avium was confirmed in 23.9% and 73.9% respectively. All samples indicated the presence of Shigella species while one sample contained Salmonella species on xylose lysine desoxycholate agar after amoebal enrichment processing. Vibrio species was not confirmed in the samples. Our results indicated a high risk of transmission of amoeba resistant bacteria through drinking water to people living in these areas.

Titanium dioxide nanoparticles were prepared using the sol-gel process. The effect of temperature and precursor concentration on particle size was investigated. The optimum conditions were then used to prepare carbon and nitrogen doped titanium dioxide (TiO2) nanoparticles. Doping was done to reduce band gap of the nanoparticles in order to utilize visible light in the photocatalytic degradation of organic compounds. A significant shift of the absorption edge to a longer wavelength (lower energy) from 420 nm to 456 nm and 420 nm to 428 nm was observed for the carbon doped and nitrogen doped TiO2 respectively. In this study, the prepared TiO2 photocatalyst was immobilized on carbon nanofibres to allow isolation and reuse of catalyst. The photocatalytic activity of the catalyst was tested using methyl orange as a model pollutant and was based on the decolourization of the dye as it was degraded. The doped TiO2 exhibited higher photocatalytic activity than the undoped TiO2. The materials prepared were characterized by XRD, TEM, SEM, FT-IR, DSC and TGA while the doped TiO2 was characterized by XPS, ESR and Raman Spectroscopy.

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

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.