The deteriorating water quality in South Africa and changing legislation requiring the industrial implementation of waste minimisation and pollution prevention technologies has highlighted the need for the investigation of new effluent treatment technologies such as advanced oxidation processes. This investigation details the evaluation of ultrasound, an emerging advanced oxidation process, to degrade organic compounds during water treatment. The objectives of the investigation included the design of a suitable ultrasonic laboratory reactor to investigate ultrasound chemistry and the sub-processes occurring during sonication. Atrazine was used as a model compound to compare the performance of ultrasound with that of ozone and hydrogen peroxide, already established advanced oxidation processes. Recommendations have also been made for the scale-up of ultrasonic processes. A 500 mL ultrasonic cell containing an ultrasonic horn as an energy source was designed and constructed. The measurement of hydrogen peroxide concentration was used as a tool to indicate the process conditions under which the formation of free radical reactions during sonication are enhanced. These include the application of oxygen and air sparging or the addition of a commercial source of hydrogen peroxide. It was found that oxygen sparging and a high acoustic power input should be used in ultrasonic processes with a short retention time, and conversely, that air sparging and a lower acoustic energy source should be used in processes with a long retention time. A flow loop system should be considered to maximise oxidation both within and beyond the sonicated zone, gas sparging should only occur within the sonication zone else the degradation of hydrogen peroxide is encouraged. Ultrasound is most effectively applied in water treatment as a pretreatment stage in combination with other technologies and not as a stand-alone process. Atrazine was used. as a model compound to compare the performance of ultrasound with ozone because of its persistence in the environment and resistance to degradation. Atrazine was degraded during sonication and ozonation. degradation increased wim the addition of hydrogen peroxide. Ozone decomposition (and hence free radical reactions) was enhanced when ozone was combined with ultrasound or hydrogen peroxide. Enhanced ozone decomposition during ozonation combined with sonication is due to the conditions (high temperatures and pressures) as well as the free radical reactions occurring within the collapsing cavitation bubbles and at the gas-liquid interface. The enhancing effect of combining ultrasound with ozone was greatest at the low ozone concentrations typically applied during water treatment. Atrazine degradation during sonication and ozonation is predominantly due to the reaction with hydroxyl radicals. Atrazine degradation products identified using gas chromatography and mass spectrometry were deethylatrazine. hydroxyatrazine and deethyldeisopropylatrazine (tentatively identified). / Thesis (Ph.D.)-University of Natal, Durban, 2001.

Globally, water turbidity remains a crucial parameter in determining water quality. South Africa is largely regarded as arid and is often characterised by limited but high intensity rainfall. This characteristic renders most of the country’s water bodies turbid. Consequently, the use of turbidity as a measure of water quality is of great relevance in a South African context. Generally, turbidity alters biological and ecological characteristics of water bodies by inducing changes in among others temperature, oxygen levels and light penetration. These changes may affect aquatic life, ecosystem functioning and available water for industrial and domestic use. Siltation, a direct function of turbidity also impacts on the physical storage of dams and shortens their useful life. To date, determination of water turbidity relies on the tradition laboratory based methods that are often time consuming, expensive and labour intensive. This has increased the need for more cost effective means of determining water turbidity. In the recent past, the use of remote sensing techniques has emerged as a viable option in water quality assessment. Hyperspectral remote sensing characterizes numerous contiguous narrow bands that have great potential in water turbidity measurement. This study explored the applicability of hyperspectral data in water turbidity detection. It explored the visible and near-infrared region to select the optimal bands and indices for turbidity measurement. Using the Analytical Spectral Device (ASD) field spectroradiometer and a 2100Q portable turbidimeter, spectral reflectance and laboratory based turbidity measurements were taken from prepared turbid solutions of predetermined concentrations (i.e. 10g/l to 150g/l), respectively. The Pearson’s coefficient of correlation and R2 values were employed to select optimal spectral bands and indices. The findings showed a positive linear relationship between reflectance, the amount of soil in water and turbidity values. The strongest relationships came from bands 528, 489, 657, 1000 and 983, reporting adjusted R2 values of 0.7062, 0.7004, 0.6864, 0.7120 and 0.6961, respectively. The highest coefficient came from band 1000nm. The strongest indices were 625/440 and (770-1000)/(770+1000), with adjusted R2 values of 0.6822 and 0.6973 respectively. The use of hyperspectral data in turbidity detection is ideal for optimal band interrogation. Although good results were generated from this study, further investigations are needed in the near-infrared region. / Thesis (M.Env.Dev.)-University of KwaZulu-Natal, Pietermaritzburg, 2013.

The Lakes of the Four Seasons, a community in Lake and Porter Counties in northwestern Indiana, contains highly eutrophic lakes. A diagnostic feasibility study of the lakes was initiated in December 1981, and continued through November 1982. Morphometric, limnological and hydrologic characteristics of the lakes were defined in order to permit the development of nutrient and hydrologic budgets for the lakes. In addition to the development of these budgets, preliminary testing of a lake restoration technique, phosphorus precipitation, was performed. These studies and the resultant budgets provided necessary information for the formulation of feasible restoration methods for the lakes. The recommended restoration methods, if implemented, could enhance and maintain water quality conducive to recreational use and aesthetic enjoyment.The Lakes of the Four Seasons system has a mass water loading of 3.596 x 106 m3 Y-1and a hydraulic residence time of 0.71 y. Mass external phosphorus loading to the lakes is 537.34 kg –1 . Mass nitrogen loading to the system is 13,457 kg y -l.Big Bass Lake has a mass water loading of 2.316 x 106 m3 y-1 and a hydraulic residence time of 0.16 y. Mass external phosphorus loading to the lake is 356.76 kg y -l. Mass nitrogen loading to Big Bass Lake is 12,260 kg y -l.Lake Holiday/Lake on the Green has a mass water loading of 3.423 x 106 m3 y 1 and a hydraulic residence time of 0.65 y. Mass external phosphorus loading to the lakes is 330.52 kg y-1. Mass nitrogen loading to the Lake Holiday/Lake on the Green is 11,980 kg y1.Both loading and in-lake nitrogen:phosphorus ratios indicated phosphorus limitation in these lakes. The eutrophic condition of the lakes was also indicated by in-lake nutrient concentrations as well as excessive algal and macrophyte growth. Rapid 02 depletion, which occurs in water overlying the sediments even though the lakes are fairly well mixed, also testifies to the extreme productivity of the lakes.Restoration options for these lakes include short term cosmetic methods, longer term options for the disruption of internal phosphorus cycling, and abatement of phosphorus loading from the watershed. The cosmetic options involve the use of herbicides and algicides to give immediate relief from excessive primary productivity. Dredging and drawdown/sediment consolidation are aired at reducing internal phosphorus loading, while methods directed at the abatement of phosphorus loading from the watershed attack the cause of the lake system's problems. The longer term options necessitate further studies before implementation.

Automatic river quality monitoring (ARQM) is potentially an important tool in water quality management for the National Rivers Authority (NRA) and similar organisations worldwide. The information produced by ARQM systems must be used in the most effective way and fully integrated with the manual monitoring effort. The status and development of ARQM systems in the freshwater and estuarine River Thames catchment are discussed and a practical appraisal of the design, operation and maintenance requirements given. Data capture, verification and presentation methods are developed and the use of ARQM data for real time management and subsequent analysis is advocated. Examples of data from the freshwater ARQM system are given which emphasise the variability of freshwater quality and the need for a comprehensive understanding of the behaviour of rivers before management decisions are made. The use of ARQM data for assessing the compliance of rivers with River Quality Objectives is examined. With respect to the tidal Thames, data processing methods to correct for the tidal movement of the waterbody are developed. ARQM data are used to highlight the principal factors affecting the water quality of the tidal Thames. The importance of the use of ARQM information in the effective management of the tidal Thames is discussed and operational examples demonstrate how it may be utilised as a basis for management decisions. The application of ARQM to the sub-tropical environment of the River Ganges, India, is investigated. An ARQM system has been designed and prototypes are operational. Extensive site surveys were carried out and the water quality status of the Ganges is discussed. Recommendations for the improvement and future development of ARQM systems are made. The use of ARQM information and its potential for improving the management of rivers is discussed.

<p>The Eerste River is a river system which has, over the years, been subjected to human interference. The purpose of this study was to investigatge temporal and spatial trends in the water quality of the Eerste River between 1990 and 2005. The study results revealed that the major trends in the water quality of the Eerste River are more spatial than temporal.</p>

Implementation of physically distributed catchment modelling systems reshapes the fundamental philosophy of traditional calibration approaches by supporting the concept of equifinality. Arising from the concept of equifinality, alternative behavioural parameter sets within a given catchment modelling system structure can generate similar levels of simulation performance. This concept is motivated by the existence of a variety of uncertainties associated with a complex catchment modelling system, such as an imperfect model structure, measurement errors in both the input data and the recorded flows, and unknown, or poorly defined, interactions among parameters. However, the difficulty of searching for behavioural parameter sets increases as the complexity of the catchment modelling systems increases. This study undertook an investigation on the feasibility and robustness of a real-value coding genetic algorithm (GA) for calibrating the physically distributed Storm Water Management Model (SWMM) using the Centennial Park catchment in Sydney as a case study. It was found that a real-value coding GA was a robust technique suitable to search for behavioural parameter sets and, in particular, it was found that this approach was capable of identifying the promising range of values for spatially variable parameters. Moreover, the widespread use of physically distributed catchment modelling systems has highlighted the importance of estimating the uncertainty in the parameter values and in the predictions obtained from a complex catchment modelling system as well as in catchment averaged, or lumped, systems that have been the focus of many previous studies. Bayesian inference has been shown to be a tool suitable for parameter uncertainty estimation in catchment modelling. However, the application of Bayesian inference faces difficulties in complex high-dimensional systems where there is little if any a priori knowledge about the proposal distribution of the parameters. In this study, a real-value coding GA was used to undertake uncertainty estimation on spatially variable control parameters with little a priori knowledge about the proposal distribution of parameters. After 50,000 evaluations, the marginal posterior distributions of spatially variable parameters which are associated with behavioural parameter sets were identified. The performance of a behavioural parameter set under a range of hydrological conditions was evaluated. Updating of the marginal distributions of these control parameters was implemented by adding additional calibration data. Interactions among the spatially variable control parameters were investigated also. Results based on the Pearson Correlation method indicate no clear relationship between any two control parameters. However, a methodology to detect relationships among groups of parameters was developed. Application of this methodology suggests that the simulation performance of SWMM was influenced by combinations of parameter values rather than values of the individual parameters. Finally, the predictive uncertainty associated with the existence of behavioural parameter sets was considered. A number of alternative strategies were used to evaluate the predictive performance. Consideration of the results suggests that use of a small number of parameter sets randomly selected from the large number of behavioural parameter sets was the best strategy in terms of efficiently obtaining predictive performance.

Corrigenda pasted onto front end paper. / One folded col. map in pocket on back endpaper. / Bibliography: leaves 348-368. / xx, 368 leaves : ill. (some col.), maps (some col.) ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Develops a framework balancing water quality costs resulting from waterborne disease, disinfection by-product exposure and aesthetic concerns, against hydraulic costs, which include pipes, pumps and tanks. The genetic algorithms developed, successfully obtained the current optimal hydraulic solution, before adapting the model to incorporate water quality issues. / Thesis (Ph.D.)--University of Adelaide, Dept. of Civil and Environmental Engineering, 2000

Thesis (doctoral)--TU Bergakademie Freiberg, 2006. / "International Mine Water Association." Includes bibliographical references (p. [337]-420) and index.

Thesis (M.E.S.)--The Evergreen State College, 2007. / Title from title screen (viewed 1/24/2008). "MES thesis." Includes bibliographical references (p. 51-54).

Thesis (Ph.D.) -- McMaster University, 1999. / Includes bibliographical references (p. 185-188). Also available via World Wide Web.