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Thesis (M.Eng.)(Chemical Engineering)--University of Pretoria, 2006. / Accompanied by a CD-ROM: Appendix B. Cooling tower model results. Includes bibliographical references. Available on the Internet via the World Wide Web.

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Made available in DSpace on 2014-10-09T12:55:14Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:06:02Z (GMT). No. of bitstreams: 0 / O quadro evolutivo da agricultura brasileira resulta em benefícios à população exigindo crescentes avanços tecnológicos no setor. Constantemente, novos agrotóxicos são introduzidos estimulando estudos científicos com a finalidade de determinar e avaliar os impactos na população e no meio ambiente. No presente trabalho, a matriz avaliada foi o lodo gerado no processo de tratamento de água para consumo humano, coletado na região do Vale do Ribeira, SP. A técnica empregada foi a cromatografia líquida de fase reversa acoplada à espectrometria de massas triploquadrupolar em tandem com ionização por electrospray. Os compostos foram extraídos previamente da matriz. O desenvolvimento da metodologia exigiu tratamento dos dados para que esses pudessem ser utilizados e transformados em informações confiáveis. Os processos envolvidos foram avaliados usando o conceito da validação de ensaios químicos. Os indicadores avaliados foram seletividade, linearidade, intervalo de trabalho, sensibilidade, exatidão, precisão, limite de detecção, limite de quantificação e robustez. Esses indicadores produziram valores quantitativos e qualitativos que foram estatisticamente evidenciados de forma objetiva. A metodologia desenvolvida e validade é simples. Como resultado, mesmo explorando a sensibilidade da técnica, os compostos estudados não foram encontrados no lodo da ETA de Registro. Isso leva a crer que esses compostos podem estar presentes em concentrações muito baixas, podem sofrer degradação durante o tratamento da água ou não são retidos completamente pela ETA. 7 / Dissertação (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP

Thesis (MTech (Chemistry))--Cape Peninsula University of Technology, 2012. / Polychlorinated biphenyls (PCBs) are known harmful chemicals which require urgent remediation, monitoring and assessment in the environment. The predominant current methods used to analyze PCBs involve expertise and are cost intensive. Most of these methods are chromatographic based techniques which are difficult to sustain in Africa due to the expensive nature of the instrument, costly running expenses and skilled labour required. These limitations face Africans, who are the most affected by the presence of PCBs in their environment as a result of improper disposal and usage of these compounds.

Sewage pollution of surface waters is a pressing issue of global concern, even in regions with extensive wastewater and sewage treatment infrastructure. Contaminants, like harmful bacteria that can cause gastrointestinal disease and hinder economic growth and development, enter natural waters through a variety of point and non-point source discharges that range from treated to untreated. With increasing urbanization, aging infrastructure, and changing precipitation patterns due to climate change, it is increasingly important to understand and predict the persistence and transport of sewage-derived bacterial pollution in surface waters. To effectively monitor and predict these contaminants, it is critical to understand sewage-derived bacteria’s extra-enteric ecology, or the ecological dynamics they experience after transitioning from a primary habitat (like the human gastrointestinal system) to a secondary habitat (like natural waters). Dynamics of fecal bacteria are assumed to be driven by loss, as commonly observed for the fecal indicator bacteria (FIB), Enterococcus sp., with sunlight exposure as the dominant driver (i.e., greatest impact on population dynamics). However, particle association of FIB may alter their persistence and transport in natural waters, though this aspect of extra-enteric ecology is rarely included in predictive models. Models predicting persistence and transport of fecal bacteria and pathogens could be improved by incorporating information on the impacts of particle association on dominant loss rates of FIB and the population dynamics of various indicated pathogenic groups. Further, it is important to understand the variation in and drivers of surface water optical properties, like water transparency, due to the likely importance of light penetration to fecal bacteria environmental persistence. This dissertation aims to address the critical knowledge gaps of how particle association influences the extra-enteric ecology of various sewage-derived bacteria and how optical properties relevant to the light-dependent mortality of FIB vary spatially and temporally in an urban-influenced water body. To do so, I employ a combination of empirical, modeling, and observational techniques. The Hudson River Estuary (HRE) is an ideal field site for this research because of its consistent problems with sewage pollution, especially following precipitation events, despite significant improvements following the Clean Water Act in 1972. Managing human health risks associated with sewage pollution is especially important for this water body that runs through the NY/NJ metropolitan area with its 19 million stakeholders. Further, previous research quantifying FIB dynamics has predominantly been conducted in clear, low turbidity water columns. Experiments constraining the dynamics of FIB in water with low clarity, like in the HRE, would fill this important knowledge gap in the field of sewage pollution monitoring and modeling. Chapter 1 assesses the impact of particle association on dominant growth rates and persistence of the brackish fecal indicator bacteria, Enterococcus sp. (also called enterococci). In this chapter, I conducted a series of natural water microcosm laboratory experiments to quantify dominant growth rates of enterococci. I then used these growth rates to parameterize a 1-dimensional advection-diffusion-decay model to simulate enterococci persistence in waters ranging from clear, quiescent lakes to turbid, turbulent waters. This combined empirical and mathematical modeling approach led to four major conclusions related to the persistence and transport of enterococci in natural waters: 1) particle association increases dominant growth rates (light-induced and dark, temperature-dependent growth) and induces sinking of enterococci, 2) particle association increases simulated enterococci persistence, 3) simulated enterococci persist longer in more turbid and/or more turbulent waters, and 4) discharge timing later in a diel cycle increases simulated Enterococcus sp. persistence. Results from this chapter demonstrate the importance of distinguishing free-living and particle-associated Enterococcus sp. in models of their persistence and transport and provide empirical data for independently constraining their population dynamics. Further, the simulated persistence indicates that sewage-derived fecal bacteria discharged into water bodies like the HRE will last longer than discharges in clear, calm waters (e.g. Lake Tahoe) and even clear, turbulent waters (e.g. coastal ocean in California). This information is broadly applicable to water quality management and indicates how variability in turbidity or turbulence within a water body could alter sewage discharge persistence and exposure risk for the public. Model sensitivity testing confirmed the consistent impact of particle association on enterococci persistence and reaffirms the need for FIB models to include particle association. An adapted version of Chapter 1 was published in Water Research (Myers and Juhl 2020). Because particle association increases enterococci persistence and growth rates, it is important to determine if particle association similarly affects co-occurring pathogenic bacteria and if particle association prevalence is similar. Chapter 2 is a valuable complement to Chapter 1 and addresses key knowledge gaps related to ambient pathogen abundance, particle association, and correlation with FIB in surface waters, in addition to the effect of particle association on dominant pathogen growth rates. In this chapter, I report multi-year observations of abundance and particle association proportions in the HRE for four bacterial genera: the fecal indicator Enterococcus sp., two enteric pathogens (Salmonella sp. and Shigella sp.) and a naturally-occurring, marine pathogen (Vibrio sp.). I found that mean particle association ranged from 34% to 49% and that overall abundances were significantly positively correlated across all genera. The second major goal of this chapter was to determine if particle association impacted dominant growth rates of pathogens similarly to the effect observed for enterococci (Chapter 1). In experiments similar to those in Chapter 1, I quantified the fraction-specific (free-living, particle-associated, and total) temperature and light-dependent growth of the three pathogenic genera. Overall, particle association consistently increased temperature- and light-dependent growth rates across genera, similarly to Chapter 1, though particle association did not benefit Vibrio sp. as much as the enteric genera. I found that Salmonella sp. had similar temperature- and light-dependent growth rates to enterococci. By contrast, Shigella sp. growth rates were greater than those of enterococci. As expected due to its different origin, Vibrio sp. also had dissimilar growth rates to enterococci. Interestingly, Shigella sp. behaved more similarly to Vibrio sp., with increasing dark period growth with temperature, which is opposite of the trend observed for the other two enteric organisms (Salmonella sp. and enterococci). The disparities and similarities of dominant growth rates between enterococci and 2 co-occurring fecal pathogens, together with the finding that abundances were positively correlated across all genera, suggests that enterococci are good indicators of recent sewage pollution, but have limitations in their use for assessing extended water column persistence of some co-occurring pathogenic bacteria. Information in this chapter is important for our understanding of FIB use to monitor sewage pollution persistence and for water quality management to minimize human exposure risk, especially in water bodies where environmental persistence is likely longer, like in turbid and turbulent waters (as shown in Chapter 1). Persistence simulations in Chapter 1 demonstrated that water transparency (modeled as diffuse attenuation of light, 3), was critical for determining the persistence of enterococci. It is then important to understand how water transparency varies throughout a water body to eventually predict how sewage bacteria persistence timescales vary. Chapter 3 examines the spatial and temporal variability of water transparency and its primary drivers (suspended particulate matter (SPM), chlorophyll, and colored dissolved organic matter (CDOM)) throughout the terrestrially- and marine-influenced HRE using observational and laboratory techniques. Data in this chapter indicate that water transparency in the HRE is predominantly controlled by SPM (measured as turbidity) and, to a lesser degree, chlorophyll. Despite some dramatic changes in inputs affecting the primary drivers (e.g. decreased sewage pollution - NYCDEP 2012, decreased chlorophyll concentrations - Caraco et al. 1997; Smith et al. 1998, and increased dissolved organic carbon transport - Findlay 2005) in the HRE, the dominance of turbidity in determining water transparency found in this study was consistent with work in the 1980s (Stross and Sokol 1989). Together, the findings by Stross and Sokol 1989 and in this chapter suggest that future work on understanding water transparency variability and its impact on sewage bacteria persistence in the HRE should focus on quantifying the variability in SPM. In contrast to other estuarine systems, CDOM absorption in this chapter minimally impacted water transparency (measured here via KdPAR). This chapter also documents spatial and temporal variability of water transparency and its primary drivers in the HRE. Turbidity and chlorophyll fluorescence varied seasonally, generally consistent with trends in other estuarine systems. Turbidity, chlorophyll, and CDOM absorption were all elevated after increased river flow from Tropical Storm Isaias. All three primary drivers of water transparency were also commonly higher for nearshore and tributary sites, as opposed to mid-channel sites, possibly due to increased shallow bed resuspension and terrestrial runoff. In the upper, freshwater portions of the estuary, CDOM absorption was highest, indicating a greater relative importance of CDOM on water transparency in this region. Data in this chapter also demonstrated that Wastewater Treatment Plant (WTP) outfalls commonly had elevated optical brighteners and (Sl(275-295), a CDOM slope ratio that indicates excess smaller CDOM molecules at a treated discharge, and a contrasting influence on CDOM absorption. This information could then allow CDOM absorption and optical brightener fluorescence to be used as indicators of treated or untreated discharges that could be measured on a faster timescale than current bacteria monitoring via culture-based techniques. Appended to this dissertation are results from experiments examining bacterial community composition for free-living and total populations in the HRE, which provide additional context for the research presented in this dissertation. The free-living and and total bacteria communities were not found to be significantly different, which indicates that there are not distinct communities in free-living and particle-associated fractions. Together with results from Chapters 1 and 2, this indicates that particle association may increase growth rates for bacteria that become particle-associated, instead of particles supporting the development of a unique and more resistant bacteria community. Four of the five fecal core families (bacteria commonly found in human fecal samples) were also identified in samples for these experiments, though relative abundance of these groups for free-living and total fractions were largely uncorrelated with each other over time. This finding demonstrates a notable influence of sewage inputs on the bacterial community in the HRE. Finally, these observations demonstrate that bacteria community composition varied seasonally, as noted by the significant influence of temperature and salinity on bacterial community composition. A wide variety of genera were strongly associated with colder (<12°C) water temperatures and samples from colder water generally exhibited higher alpha diversity. The findings from this dissertation have significantly contributed to our understanding of the extra-enteric ecology of the fecal indicator bacteria Enterococcus sp. and multiple co-occurring potential pathogens. This dissertation demonstrates that particle association must be considered in models of sewage-derived bacteria persistence. This dissertation also deepens our current understanding of water transparency drivers and their spatial and temporal heterogeneity in the turbid and turbulent system of the HRE. The results from this dissertation are useful for improving predictions of sewage pollution persistence and, by extension, minimizing human exposure risk to potentially harmful bacteria. These findings are broadly applicable beyond the HRE, to water bodies of varying turbidity and turbulence conditions.

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When mining activities in some parts of the Witwatersrand were discontinued in 2000, the defunct workings started to flood. In September 2002 the mine water started to decant from the West Rand Mine Basin (WRB) next to the Tweelopie East Stream. Treated water is currently used in the mine's metallurgical plants and 15Ml per day of treated water is disposed firstly into the Cooke Attenuation Dam and then discharged into the Wonderfonteinspruit. The aim of this study was to find and provide remediation measures as a result of acid mine drainage and other impacting factors on the water quality and volume in the Wonderfonteinspruit. Conductivity and total dissolved solids (TDS) were highest at the point where the tailings dam leached into the Wonderfonteinspruit. Sulphate was very high as was expected due to acid mine drainage. The best way to treat the high sulphate levels is with sulphate-reducing bacteria. To avoid the fatal flaw of many other constructed wetlands, a continuous carbon source is provided to the bacteria in the form of activated sewage from the Flip Human sewage treatment plant. Iron and other heavy metals are being precipitated through oxidation reactions to form oxides and hydroxides from the aerobic cell in the wetland. The wetlands are also known for their ability to reduce nitrate and microbial values with great success. In the remediation, four elements that currently do not comply with the SABS criteria for class 0 water, were chosen for improvement: conductivity, dissolved solids, sulphate and iron. Conductivity falls within class 1 and has a maximum of 178 mS/m @25ºC that should be reduced to under 70 mS/m. Total dissolved solids have a value of 1585 mg/l, which is much higher than the prescribed 450 ml/l, making it class 2 water. The last two problematic elements are both considered as class 2 water: sulphate peaks at 592 mg/l where the preferred value is 200 mg/l, and iron should be 0.01 mg/l, not the staggering 0.3mg/l. iv Alternative mitigation methods were identified and analysed for the impacts of the five major contaminators and ultimately the solution comes down to constructed wetlands. This is not a straightforward solution, however, and a specific design to accommodate all the different pollutants and water quality ranges was proposed. The other mitigation methods include a cut-off trench and pump-back system for the tailings dam, as well as the implementation of a monitoring programme. The sewage works should be optimised and better managed. Both the settlement and agricultural sector need to be educated on their representative impacts on the environment and government assistance should be available. / ENVIRONMENTAL SCIENCES / MSC (ENVIRON MANAGEMENT)