Water scarcity is one of the biggest issues we have to face as population and water consumption levels increase despite a fixed supply of renewable fresh water. Meeting the challenges that water scarcity poses to food production, ecosystem health, and political and social stability will require new approaches to using and managing water. Desalination already plays an essential role in water management. It constitutes a secure source of safe drinking water supply once demand management measures are fully implemented. Overcoming problems related to brine minimization and disposal is key to sustainable, efficient inland water desalination. The main focus of this was the investigation of technical limits and improvements for application in inland desalination. The first part of the dissertation covers the study of Membrane Distillation (MD) for desalination of water. The second part provides a broad perspective of Reverse Osmosis (RO), pretreatments -comparison of slow sand filtration and microfiltration-, post-mortem study of membranes to determining fouling and scaling causes, and RO brine minimization via Vibratory Shear Enhance Processing (VSEP®) for use in RO brine minimization. The study of Vacuum Membrane Distillation in a hollow fiber membrane was studied. Experimental work is supported by an original mathematical model to expose the physics of VMD and support predictions that extend VMD results beyond these generated in the laboratory. The advantages and disadvantages of each pretreatment, including their effects the effect on the performance of RO, a post-mortem membrane study and an economic analysis. The post-mortem study of membranes used during Yuma Desalting Plant operation. This work was used to identify the best pretreatment and more suitable membrane to treat saline water in the lower Colorado River. The work performed during the brine minimization study using VSEP®. This study included experimental data and an extensive economic analysis comparing Ion Exchange (IX) as pretreatment and VSEP® as post-treatment for RO.

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A functional beverage, designed to be cardio-protective, was formulated, using a blend of juices of cranberry (Vaccinium macrocarpon L), blueberry (Vaccinium angustifolium Aiton.), apple (Malus domestica L.), ginger (Zingiber officinale Roscoe) and selected cardio-protective ingredients. Membrane filtration enhanced the antioxidant properties of the fruit juices. Ultrasound-assisted water extract of ginger showed potential antioxidant activities. The selected fruit juice combination, 50% blueberry; 12.5% cranberry; and 37.5% apple, showed higher consumer acceptability. Incorporation of functional ingredients at 10% RDI and 2% (v/v) ginger extract did not affect the sensory properties of the beverage. Phenolic concentration, FRAP value, and % LDL oxidation inhibition of the formulation were 1024 mg GAE/L, 3114 mg TE/L and 45%, respectively. Diet supplementation with the formulation resulted in lower serum and liver lipid levels in spontaneously hypotensive rats. Blood pressure was reduced by the formulation after two but not four weeks supplementation.

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According to the Department of Water Affairs (DWAF, 2004 p.15), South Africa’s water resources are scarce and extremely limited and much of this precious resource is utilised and consumed in our industries. Treatment and re-use of effluent generated is, in some cases, preferred over use of alternate water resources (Du Plessis, 2008 p.3). The volume of effluent generated in treatment processes like ultra-filtration (UF) and reverse osmosis (RO) units is determined by the feed water quality, with high water loss through effluent generation at poor feed water quality. Current UF and RO applications require an increased UF production capacity due to the use of UF filtrate for periodic backwashing of the UF membrane units. This results in loss of water and decreases overall recovery. The need therefore exists to increase the overall recovery of product water from the raw water stream by reducing the amount of effluent generated. This would be possible to achieve by using RO brine to backwash the UF unit. The study was conducted to provide a modelling tool, assisting management to optimise the use of RO brine as backwash water on the UF system at the Medupi power station. The secondary objective of this study was the development of a modelling tool that can be used for other projects, new or existing, as a measure and indication of the usability of RO brine as backwash water on UF systems. By successfully applying this newly developed model, the viability of utilising the RO brine as backwash water for the UF was investigated. This modification would lead to utilizing smaller UF units than previously envisioned, which in turn leads to reducing capital cost with 11.07% and operating expenditure with 9.98% at the Medupi power station. This also has a positive environmental impact by reducing the amount of raw water used monthly by 10.34% (108 000 m3/month). / MIng (Development and Management Engineering), North-West University, Potchefstroom Campus, 2014

South Africa's water resources are, in global terms, scarce and extremely limited (DWAF, 2004). Groundwater is a valuable source of potable water in South Africa. It was found that most of the health facilities in the Limpopo Province depend on groundwater as sole source of potable water. Groundwater quality is to a great extent influenced by the dominant land use in the vicinity of an aquifer. It is therefore important to carefully manage possible pollution sources of anthropogenic origin. This may be seen as pro–active water quality management that may result in significant saving on water treatment. This aim of this study is to obtain a regional view of the water quality situation at clinics and other health facilities in the Limpopo Province. It was found that the general water quality at health facilities in the Province is questionable. It is of concern to note that 56% of health facilities use water that is unacceptable for human consumption. Water quality may be managed by introducing appropriate treatment options to treat the water to ideal water quality standards. This dissertation explores some treatment options used at health facilities in the Province. The efficiency of these treatment systems is also investigated. / Thesis (M.Sc. (Geography and Environmental Studies))--North-West University, Potchefstroom Campus, 2011.

South Africa's water resources are, in global terms, scarce and extremely limited (DWAF, 2004). Groundwater is a valuable source of potable water in South Africa. It was found that most of the health facilities in the Limpopo Province depend on groundwater as sole source of potable water. Groundwater quality is to a great extent influenced by the dominant land use in the vicinity of an aquifer. It is therefore important to carefully manage possible pollution sources of anthropogenic origin. This may be seen as pro–active water quality management that may result in significant saving on water treatment. This aim of this study is to obtain a regional view of the water quality situation at clinics and other health facilities in the Limpopo Province. It was found that the general water quality at health facilities in the Province is questionable. It is of concern to note that 56% of health facilities use water that is unacceptable for human consumption. Water quality may be managed by introducing appropriate treatment options to treat the water to ideal water quality standards. This dissertation explores some treatment options used at health facilities in the Province. The efficiency of these treatment systems is also investigated. / Thesis (M.Sc. (Geography and Environmental Studies))--North-West University, Potchefstroom Campus, 2011.

South Africa is on a path of dramatically increasing its energy supplying capabilties. Eskom (the main utility supplying electricity to the national grid) recently announced that future power station technologies will focus on renewable energy and nuclear power. This is done in an effort to reduce South Africa’s dependance on burning fossil-fuels and thereby decreasing CO2 emissions and other harmful gases. This, together with the fact that there are a lot of fresh water scarce areas especially along the Eastern Cape coast of South Africa, is what inspired this study. This study investigates the use of a 200 MWth High Temperature Reactor (HTR) for cogeneration purposes. Heat from the reactor is utilised for electricity generation (Rankine cycle) and process heat (desalination). Two desalination concepts were evaluated thermodynamically and economically, namely Multi-Effect Distillation (MED) and Reverse Osmosis (RO). Computer software, Engineering Equation Solver (EES), was used to simulate different cycle configurations, where the heat available in the condenser was increased successively. The coupling of the two desalination technologies with a HTR was compared and it was found that a RO plant produces nearly twice as much water while sending the same amount of electricity to the grid (compared to coupling with MED). Coupling options were investigated and each simulation model was optimised to deliver maximum output (power and water). The best configuration was found to be the coupling of a HTR with a RO plant producing 86.56 MW generator power. This is equal to 2077 MWh/day. Using 332 MWh/day for desalination through RO, delivers 73 833 m3/day fresh water and results in 1745 MWh/day sent to the grid. This scenario is the best option from a thermodynamic and economic point of view. From an investment point of view, it will produce an Internal Rate of Return (IRR) of 10.9 percent and the Net Present Value (NPV) is calculated to be R 2,486,958,689. The results and analysis for the different cycle configurations are presented in such a way that an easy comparison can be made. / Thesis (M.Ing. (Nuclear Engineering))--North-West University, Potchefstroom Campus, 2011

Water recycling by membrane treatment is widely accepted as a leading alternative water source. This separation process creates a concentrated stream (called concentrates), containing most of the pollutants in 10%-20% of the flow; and a treated water stream. As nitrogen is a major concern, environmental regulations have become more stringent, requiring additional treatment to meet effluent standards. Other concerns include organic contaminants and potential production of halogenated organics if disinfection of the reject was applied. One option to address the problem of dissolved organic nitrogen and carbon is advanced oxidation. This oxidation could lead to degradation of refractory organic materials, which are poorly removed in conventional treatment. This project aims to evaluate treatment extent and cost of alternatives for organic (particularly nitrogen) removal in reject water addressing the following research gaps: (i) identifying the key organic pollutants present in the concentrated stream, (ii) the effectiveness and optimisation of coagulation, ion exchange and advanced oxidation; (iii) apparent cost of the different treatment methods. The untreated reverse osmosis concentrates were collected from two treatment plants:- Luggage Point, and Bundamba, both near Brisbane, Queensland, Australia. The first contains more colourful of organics than the second plant. Stirred cell fractionation with ultrafiltration membranes was used to characterise the removed key pollutants, as it offers better accuracy and reproducibility compared to centrifugation fractionation. Fluorescence spectral was used to monitor and identify specific organic compounds. The largest fraction was smaller sized <1kDa. This is probably small humic substances and fulvic acids, as indicated by Excitation Emission Matrix (EEM) analysis. A smaller portion of soluble microbial products (SMPs) also contributes to the concentrates. Bundamba contains large non coloured organics including organic nitrogen with elevated ammonia-N. In contrast, Luggage Point has higher colour, inorganic carbon and conductivity with less ammonia-N. Advanced Oxidation Process (AOP) was the most effective treatment method (high removal of organics, e.g. 55% COD of initial), followed by magnetised ion exchange (MIEX) and coagulations. For UV/H2O2 AOP, the optimal operating condition 400mg.L-1 H2O2 and 3.1kWh.m-3 energy input resulted in organics removals up to 55% with complete decolourisation. The effective reduction was found in all size ranges, preferably in >1kDa. Low inorganic carbon and salinity in Bundamba may allow better overall oxidation rates. MIEX also performed better in Bundamba with organic removals up to 43% and 80% decolourisation at the optimum resin dose of 15mL.L-1. Removal was preferential in size range of >3kDa, with more proportional percentage for decolourisation. Similarly, ferric coagulation removed a wider size range of organics. Further, ferric achieved better organic removal in Luggage Point with up to 49%. At the same molar dose (1.5mM), ferric is superior to alum, especially in Bundamba where there were less hydrophobic compounds according to EEM. Alum is poor for treatment of high organics with less coloured water. MIEX with an operational cost (chemicals and power only) of $0.14-$0.20.m-3 treated water seemed to be the most effective treatment overall. The resin achieved better results with a slightly higher cost than coagulation, and had a lower environmental impact due to reduced sludge production. AOP offers better treatment, but at a higher cost ($0.47.m-3 treated). Combined alternatives may benefit the removal effectiveness. Furthermore, more specific identification of contaminants should be investigated separately to choose appropriate treatment for priority chemicals. Another issue is further investigation of costing, including capital, and full environmental impact of treatment.

Most common inorganic foulants in RO processes operating on brackish water are calcium carbonate, calcium sulphate and silica. However, silica fouling is the recovery limiting factor in RO system. Silica chemistry is complex and its degree of fouling strongly depends on the silica solubility and its polymerization under different operating conditions of RO process. In several studies carried out in batch and dynamic tests, the presence of polyvalent cations and supersaturation of silica in solutions were found to be the important factors (apart from pH and temperature) that affected the rate of silica polymerization and its induction period. Agitation did increased silica solubility; however, its effect was negligible in presence of polyvalent cations. Alkalization of water solution by coagulants particularly sodium hydroxide was found suitable for silica removal during pretreatment. The presence of magnesium in solution played a key role in silica removal mostly by the mechanism of adsorption to the metal hydroxide. The options of inline mixing (high agitation) for 5 to 10 minutes and microfiltration before RO were found suitable for silica pretreatment. During dynamic tests, the most dominant mechanism for salt deposition (mostly CaSO4) was particulate type in high concentration water solution; while crystallization fouling was the prevailing mechanism of deposition (mostly CaCO3 and silica) in low concentration solution. Silica showed significant effect on size and shape of inorganic salt crystals during coprecipitation. Moreover, the presence of common antiscalants promoted silica fouling. This important finding recommends an extra caution while using antiscalants in case feed water contains silica to a level that can attain saturation near membrane during RO process. A model was developed to predict the silica fouling index (SFI) based on the experimental data for induction period of silica polymerization. The model takes into account the effect of polyvalent cations and concentration polarization near membrane during RO process. It provides a conservative basis for predicting the maximum silica deposition in RO process at the normal operating conditions. A generalised correlation, which was developed for determination of the mass transfer coefficient in RO process, incorporated the effect of temperature change that is usually not considered in previous correlations. A correlation for reduction of silica content in feed water, down to a safe limit of 15 ppm for RO process, was also formulated and validated by the experimental results.