[pt] Os minérios de cobre-molibdênio são beneficiados juntos normalmente pelo processo de flotação com a ajuda de coletores sulfidrílicos de relativa seletividade. Os concentrados bulk obtidos devem ser processados com o intuito de remover aqueles coletores empregados, pois eles são prejudiciais na etapa de separação por flotação diferencial, ou seja, na obtenção de concentrados de molibdênio de alta qualidade com baixos conteúdos de cobre e ferro. O processo de flotação bulk é realizado em condições oxidantes na presença de coletores sulfidrílicos (xantatos, etc.). Na prática industrial na etapa de flotação diferencial, estes concentrados bulk são separados por modificação do potencial eletroquímico da polpa para valores considerados redutores -300 a -450 mV, com hidrosulfeto de sódio (NaSH) ou o reagente Nokes (Penta-sulfeto de fósforo dissolvido em hidróxido de sódio) além de cianeto de sódio em alguns dos casos, para melhorar a eficiência do processo. Neste quadro, o processo industrial de separação seletiva produz efluente e gases perigosos como o H2S e HCN que devem ser controlados adequadamente. Este trabalho visa avaliar o uso do reagente ácido pseudo glicol tiouréia (PGA) e ácido tioglicólico (TGA) como alternativas ao processo industrial voltado para a separação seletiva dos minerais de cobre e molibdênio. Para a avaliação do depressor foram empregadas medições de ângulo de contato, potencial zeta, testes de flotação em célula Partridge-Smith (PS), FTIR e testes em célula de bancada em um planejamento experimental. O reagente estudado apresentou boas propriedades depressoras para minerais de cobre. Nos resultados das medições de ângulo de contato, pelo método de bolha cativa, foram encontrados valores maiores para a calcopirita do que para a molibdenita (até 10 graus de diferença) e medidas entre 60 e 70 graus, porém no pH ácido esta diferença diminui e os dois minerais apresentam quase o mesmo ângulo de contato 60 mais ou menos 1 grau. Nas medidas efetuadas não foi empregado o coletor final (querosene) para a molibdenita devido a sua falta de homogeneidade na emulsão para realizar as medidas de ângulo de contato. Nos testes de flotabilidade na célula PS em misturas binarias de calcopirita-molibdenita foram encontradas na faixa ácida, valores de pH nos quais há melhores relações de concentração e recuperações, na ordem de 67 por cento para a molibdenita e apenas 10 por cento para a calcopirita no produto flutuado. Os resultados usando o reagente NaSH em condições similares apresentam recuperações similares de molibdenita, mas na faixa básica do pH. Baseados nestes resultados foram avaliadas diversas variáveis e gerado um planejamento experimental para passar à escala de bancada onde foram obtidas recuperações de 84 por cento no concentrado rougher com apenas 13 por cento de cobre corroborando as boas propriedades do depressor estudado. / [en] Copper-molybdenum porphyry deposits worldwide are exploited industrially by flotation of the ores of interest into a BULK concentrate with the aid of sulfhydryl collectors of high efficiency and low selectivity. The bulk concentrate obtained should be reprocessed in order to remove those collectors employed in the bulk stage since they impair the differential flotation during the separation step in order to obtain clean high quality molybdenite concentrates at low contents of copper and iron. The bulk flotation process is conducted under oxidizing conditions in presence of sulfhydryl collectors (xanthates, etc.). In industrial practice these bulk concentrates are then separated by modification of the pulp electrochemical potential to values considered reducing, between -300 to-450 mV, with sodium hidrosulphide (NaSH) or Nokes reagent (phosphorus pentasulfide dissolved in sodium hydroxide). Addition of sodium cyanide in some cases is used to improve process efficiency. Bulk concentrates produced are however a very small portion of the processed mineral (only 1/50 of the total ore milled), these industrial processes produce waste effluents and hazardous gases such as H2S and HCN if not adequately controlled. This dissertation seeks to assess the reagent pseudo glycol tiourea acid (PGA) and thioglycolic acid (TGA) as an alternative to industrial processing for the selective separation of minerals of copper and molybdenum. On the evaluation of this depressant were used contact angle measurements, zeta potential, flotation tests in Partridge-Smith cell (PS), FTIR and bench scale flotation testing cell with an experimental design. The reagent studied showed good depressant properties for copper minerals according to the results presented. Within the results of the contact angle measurements with the captive bubble technique were found greater contact angles for chalcopyrite than for molybdenite (up to 10 degrees difference) and values between 60 and 70 degrees, however in acidic pH this difference decreases and both minerals have almost the same contact angle as of 60 more or less 1 degree. Though on the contact angle measured values it was not employed the final collector (kerosene) for molybdenite due to lack of homogeneity on emulsions to make the contact angle measurements. On floatability tests (on PS cell) with binary mixtures of chalcopyrite-molybdenite were found pH values on the acidic range, at which good concentration ratios and recoveries in the order of 67 percent of molybdenite with only 10 percent of the chalcopyrite were obtained. The results using NaSH reagent under similar conditions gave similar recoveries for molybdenite, however it was found in the basic pH range. Based on the results, several variables were evaluated and an experimental design employed on bench scale flotation tests, the results showed recoveries of 84 percent were obtained in the rougher concentrate with 13 percent copper corroborating the good properties of this depressant.

Le procédé actuel de fabrication des combustibles nucléaires MOX (UO2-PuO2) est réalisé exclusivement par voie sèche (broyage-tamisage des poudres, pressage et frittage). Afin d’améliorer ce procédé, des recherches sont menées sur le développement d’un procédé de fabrication du MOX par voie liquide. Ce procédé vise à réduire l’empoussièrement des boîtes à gants, améliorer l’homogénéité U/Pu et diminuer la quantité de défauts (fissures, éclats) des pastilles frittées, afin de minimiser le taux de pastilles rebutées. Dans cette optique, le proceed voie liquide étudié consiste à préparer une suspension aqueuse à partir des poudres brutes d’oxydes (mélange d’eau, d’additifs organiques et de poudres), puis à lui faire subir une granulation. Les granules obtenus sont ensuite pressés et frittés. Le procédé de granulation étudié est un procédé innovant de granulation cryogénique, consistant à atomiser la suspension dans de l’azote liquide puis à lyophiliser les granules gelés ainsi formés. L’étape clé du procédé est la préparation de suspension aqueuse de poudres UO2-PuO2, qui doit être dispersée, homogène, stable et suffisamment fluide pour l’étape de granulation. Une étude préliminaire a été réalisée avec des poudres simulantes, choisies pour leurs propriétés en suspension : TiO2 et Y2O3 pour simuler respectivement UO2 et PuO2. Une fois maîtrisé avec les poudres simulantes, ce procédé a été étudié avec UO2 et PuO2 pour déterminer ses conditions optimales de mise en oeuvre. La dispersion de suspensions d’UO2 et/ou de PuO2 a été étudiée par acoustophorométrie et rhéologie afin d’optimiser leur formulation, ainsi que l’étape de granulation cryogénique. Enfin, des pastilles d’UO2 et d’UO2-PuO2 ont été formées à partir des granules, puis leur frittage et leur microstructure ont été étudiés. / The current manufacturing process for MOX nuclear fuels (UO2-PuO2) is carried out by dry route exclusively (grinding, sieving, pressing and sintering). In order to improve this process, research is conducted to develop a liquid route MOX manufacturing process. It aims to reduce glove boxes dusting, increase U/Pu homogeneity and reduce the amount of defects (cracks, voids) in sintered pellets, in order to minimize scraps. In this scope, the liquid process studied consists in the preparation of an aqueous suspension from the raw oxide powders (mix of water, organic additives and powders), which is then granulated. The resulting granules are pressed into pellets and sintered. The granulation process studied is an innovative freeze granulation process that implies to spray the suspension in liquid nitrogen and then freeze-dry the frozen granules that are formed.The key step of the process is the preparation of aqueous suspension of UO2-PuO2 powders, which must be dispersed, homogeneous, stable and fluid enough for the granulation step. A preliminary study was carried out using surrogate powders, chosen for their properties in suspension: TiO2 and Y2O3 to surrogate UO2 and PuO2 respectively. Once mastered with surrogate powders, this process was studied with UO2 and PuO2 to determine its optimal working conditions. The dispersion of UO2 and/or PuO2 suspensions was studied by acoustophorometry and rheology in order to optimize their formulation, as well as the freeze granulation step. Finally, UO2 and UO2-PuO2 pellets were shaped from the granules, and their sintering and microstructure were studied.

Charles University Faculty of Pharmacy in Hradec Králové Department of Pharmaceutical Technology Consultant: doc. RNDr. Milan Dittrich, CSc. Student: Andrea Balciarová Title of Thesis: Formulation and testing of rifampicin-loaded branched polyesters nanoparticles In presented thesis, the main attention in theoretical part is focused on nanoparticles for targeted drug delivery, their types, structure and carriers used for their preparation. Moreover, in this part there is an overview of physicochemical characteristics and preparation methods of polymeric nanoparticles applicable in formulation of pharmaceutical products. The experimental part is concerned on studying the influence of the concentration of biodegradable polymers, the presence of cationic surfactants and rifampicin as model drug substance on nanoparticles΄ size and zeta-potential. The main attention is given to nanoparticles decoration with anionic biopolymers, hyaluronic acid and xanthan gum. The simple method of preparation which is usable in nanosystems formulation that influence biological functions purposefully was tried and tested in different contexts.

Thesis title: Formulation and characterization of oxime loaded PLGA nanoparticles Author: Ramin Hafezi Supervisor: PharmDr. Eva Šnejdrová, Ph.D. Advisor: PharmDr. Juraj Martiška, Ph.D. Department: Department of Pharmaceutical Technology The diploma thesis was focused on PLGA nanoparticles (NPs) which could be loaded with oximes, prepared by a double emulsion technique, and characterised by size, polydispersity and zeta potential. The theoretical part deals with the most common methods of the NPs preparation, the polymers and stabilizers employed, and drug delivery to brain. In the experimental part the effect of various formulation factors on NP characteristics were studied: linear or branched PLGA derivative, the concentrations of polymer, the volumes of primary emulsion. Dichloromethane (DCM) or Dimethyl sulfoxide (DMSO) as solvent for polymers were used and Poloxamer 407 or Didodecyldimethylammonium bromide (DDAB) as an outer phase stabilizer were employed. By comparison among the collected results, it seemed 1% A2 in DMSO and stabilization with poloxamer 407 could be best candidate for the oxime loaded drug delivery systems as it was possible to produce nanoparticles with size from 152 to 168 nm with PDI of below 0.15. Electrostatic stability in case of using DDAB was resulted excellent and...

[pt] Neste estudo, as propriedades bacterianas da estirpe Rhodococcus ruber in natura e ativada com NaOH 0,1M, foram analisadas. O estudo avaliou a influência dos cátions metálicos (Al3 positivo, Cr3 positivo, Fe3 positivo, Co2 positivo, Mg2 positivo e Ni2 positivo) sob o comportamento da estirpe bacteriana, no intervalo de concentração entre 10(-3) a 10(-6) mol/L. As amostras bacterianas foram caracterizadas por espectroscopia na faixa do infra-vermelho com transformada de Fourier (FTIR). O ponto isoelétrico (PIE) da estirpe R. Ruber foi obtido através das análises de potencial zeta. Os resultados demonstraram um PIE com pH igual 2,4 para a estirpe in natura, já quando ativada com NaOH 0,1M o PIE não foi evidenciado. A superfície bacteriana da estirpe ativada se apresentou levemente mais negativa do que a superfície da bactéria in natura. Para todas as amostras, observou-se alteração no potencial zeta durante a interação bacteriana com os íons estudados. Os resultados não apresentam diferenças significativas entre a bactéria in natura e ativada. As amostras permaneceram carregadas negativamente nos pH estudados, para todos os cátions, exceto Fe3 positivo. Por fim, diante dos resultados apresentados, acredita-se que a estirpe Rhodococcus ruber é uma opção viável para estudos voltados ao tratamento de efluentes contaminados por metais. / [en] In this study, the Rhodococcus ruber bacterial strain properties of in nature and activated with 0.1M NaOH were analyzed. The study evaluated the influence of metal ions (Al3 plus, Cr3 plus, Fe3 plus, Co2 plus, Mg2 plus and Ni2 plus) on the behavior of the bacterial strain in the concentration range from 10(-3) to 10(-6) mol/L. Bacterial samples were characterized by infra-red spectroscopy - Fourier transform Infra-red (FTIR). The isoelectric point (IEP) of the bacterium R. ruber was obtained by analysis of zeta potential. The results showed an IEP at pH equal 2.4 to strain in nature, in the other hand the IEP of activated strain (0.1M NaOH) was not observed. Bacterial surface-active strain showed slightly more negative than the surface of the bacterium in nature. All samples demonstrated changes in pH zeta potential during bacterial interaction with the analyzed ions. Samples remained negatively charged at the pH studied to all cations except Fe3 plus. Finally, it s believed that the bacterium Rhodococcus ruber is a viable option for the treatment of metal contaminated wastewater.

L'émergence de bactéries multirésistantes dues à une utilisation abusive d'antibiotiques est devenue l'une des menaces les plus dangereuses pour la santé publique. Le développement de nouveaux médicaments et la recherche d'agents antibactériens non traditionnels ont conduit à la nanotechnologie en tant que solution potentielle à ce problème. Les nanoparticules d'argent (NPs d’Ag) sont largement connues pour leur effet antibactérien. Cette étude vise à synthétiser des NPs d’Ag avec différents revêtements et à relier leurs propriétés physico-chimiques à leurs activités biocides, en mettant l'accent sur la façon dont leur charge de surface (estimée par leur potentiel zêta) affecte leurs efficacités antibactériennes et anti-biofilm. Les NPs d’Ag ont été synthétisées en utilisant du citrate comme agent de stabilisation et du polyvinylpyrrolidone, du polyéthylène glycol, de la chitosane et du polyéthylèneimine comme revêtements. La Spectroscopie de Masse à Plasma Inductif de Particule Unique, la Diffusion de Lumière Dynamique et les mesures de potentiel zêta ont été utilisées pour caractériser les NPs d’Ag préparées. La caractérisation des formulations de nanoparticules a montré qu'elles avaient des diamètres similaires d'environ 10 nm et des charges allant de -46 mV à 16 mV. Les comptages de plaques d'agar et les tests de micro dilution ont montré que les NPs d’Ag synthétisées étaient très efficaces pour empêcher la croissance des cellules bactériennes Escherichia coli. Des biofilms d'E. coli ont été cultivés et exposés aux NPs d’Ag, puis vérifiés à l'aide d'une microscopie à balayage laser confocal montrant que les formulations de NP avec un potentiel zêta négatif avaient plus d'activité anti-biofilm que les NP chargées neutres ou positives. / The emergence of multidrug resistant bacteria due to the misuse of antibiotics has become one of the most dangerous threats to public health. Development of new drugs and the search for non-traditional antibacterial agents have led to nanotechnology as a potential solution to this problem. Silver nanoparticles (Ag NPs) are widely known for their antibacterial effect. This study aims to synthesize Ag NPs with different coatings and relate their physicochemical properties with their biocidal activities, with special emphasis on how their surface charge (estimated via their zeta potential) affects their antibacterial and antibiofilm efficacies. Ag NPs were synthesized using citrate as a stabilizing agent and polyvinyl pyrrolidone, polyethylene glycol, chitosan and polyethyleneimine were used as coatings. Single Particle Inductively Coupled Plasma Mass Spectroscopy, Dynamic Light Scattering, and zeta potential measurements were used to characterize the prepared Ag NPs. Characterization of the nanoparticle formulations showed that they had similar diameters of around 10 nm and charges ranging from -46 mV to 16 mV. Agar Plate Counts and microdilution assays showed that the synthesized Ag NPs were very effective in preventing growth of Escherichia coli bacterial cells. E. coli biofilms were grown and exposed to the Ag NPs and checked afterwards with a confocal laser scanning microscopy showing that NP formulations with a negative zeta potential had more anti-biofilm activity than neutral or positive charged NPs.

Water quality and space constraints have become major concerns regarding the No. 7 waste water dam at Petra Diamonds’ Cullinan mine. The unique location of the dam constrains further development, while unsustainable accumulation of waste water inside the dam increases the risk of potential environmental contamination from seepages and spillages. The dam retains a significant amount of very poor quality water. Its excessively high pH, dissolved salt content, density and extreme turbidity result from the concentration of natural weathering products of the diamond bearing kimberlite ore. The turbidity results from the dispersion of colloidal chlorite, saponite and nontronite clay. Along with the chemistry of the solution, their colloidal shape contributes equally significantly to the non-settlement of these suspended clays. Flocculation of the dispersed clay particles will provide (a) for easy and effective separation of the clay material from the waste water and (b) more convenient options for water treatment (and subsequent redistribution) This study was aimed at contributing to a better understanding of the dynamic interactions in the No 7 Dam system to contribute towards identifying a suitable means/method for chemical flocculation of the clay particles. The individual components of the system (clays, water quality) and influx contributors (kimberlite and its leachate) were systematically characterized by means of X-Ray Diffraction, X-Ray Fluorescence, petrographic microscopy, electron microscopy, electrophoretic mobility and standard water- and soil quality analyses. The baseline quality of the Cullinan kimberlite leachate was obtained based on ASTM D5744 principles. It was found that adjusting the pH-level and ionic strength of the waste water to the critical coagulation point (cK) (as determined by electrophoretic mobility and batch jar experiments) automatically induced coagulation. Higher valence cations were displaced from pH dependent surface charge sites by proton adsorption. The resultant increased ionic strength, in combination with decreased thickness of the ionic double layer, was sufficient for the automatic initiation of high strength disordered face-face and edge-face bonds. During batch Jar tests, flocculation initiated within 4 minutes after the addition of HCl (0.5 M) and total sedimentation completed within 3 hours. The use of commercial flocculants might decrease the sedimentation time. As expected a significant increase in dissolved salt content of the clear supernatant was observed. No re-dispersion of the dried clay occurred. Throughout the study geochemical modeling was performed with PHREEQC software to identify/determine possible effective experimental conditions, minimizing experimental time and expenses. The program was also used to model outcomes of the possible water treatment options, indicated in literature as viable options for similar situations. These options can be tested to extend upon the current research. / MSc (Environmental Sciences), North-West University, Potchefstroom Campus, 2015

The freshwater dinoflagellate species, Ceratium hirundinella (C. hirundinella) possesses unique characteristics, such as a thecal-plate cell covering of cellulose, spines and flagella. Unlike most other algae and cyanobacteria, C. hirundinella cells are relatively large in size (up to 450 μm in length and 50 μm in width). These unique characteristics (e.g. cell covering and flagella) and adaptations (e.g. spines) give the dinoflagellate cells the ability to reduce their sinking rate from the euphotic zone and to migrate easily through the water column. When source water contains high concentrations of C. hirundinella cells, water treatment problems and poor aesthetic water quality can be expected. These water treatment problems may include 1) the disruption of coagulation and flocculation, 2) clogging of sand filters and 3) taste and odour problems when cells penetrate into the final water. In Chapter 9 of this study, a list of operational guidelines (including alert levels) and recommendations to assist managers and operators of plants when C. hirundinella cells are causing water treatment problems. During events of high C. hirundinella concentrations in source water, managers and operators of conventional water treatment plants need strategies to optimize coagulants and unit processes. Thus when source water contains motile nuisance algae, such as C. hirundinella, in moderate or abundant quantities, it is advisable to conduct jar stirring test experiments using both turbidity and total photosynthetic pigment (or chlorophyll-a) analyses as indicators of appropriate coagulant choice and dosages. The aims of this study are summarized as follows:  To optimize coagulants and conventional water treatment processes by implementing relevant algal removal strategies and indicators during jar stirring test experiments,  To investigate the changes in surface charge (known as zeta potential) on C. hirundinella cells before and after adding coagulants as part of the treatment processes,  To investigate the physical and chemical impacts on the morphology of C. hirundinella cells after coagulation, flocculation and sedimentation,  To identify organic compounds that may be responsible for taste and odour problems associated with C. hirundinella,  To investigate the efficiency of pre-chlorination on the removal C. hirundinella cells when dosing various coagulants, and  Give recommendations and operational guidelines relevant for a conventional water treatment plant to improve C. hirundinella removal A combined water treatment system (Phipps and Bird Model), consisting of a six paddle jar test apparatus and six sand filter columns, was used to simulate conventional processes (coagulation, flocculation, sedimentation and rapid sand filtration). Source water samples containing relatively high C. hirundinella concentrations (> 500 cell/mℓ) were collected from Benoni Lake (26º10’50.40’’S; 28º17’50.11’’ E) in plastic containers and stored as a homogenous sample in a 200 litre container under laboratory conditions (± 22 °C). Samples were collected from the source water as well as after sedimentation (from the supernatant or sludge) to determine turbidity, total photosynthetic pigment analyses (chlorophyll) and for phytoplankton analyses. Flocs (containing C. hirundinella cells) were collected from the sludge or sediment for scanning electron microscopy investigations and to perform zeta potential analyses. Concentrated C. hirundinella samples were frozen at -80 °C according to the proposed sampling protocol for organic compound analyses. Results obtained from this study proved that using the relevant indicators to determine the appropriate coagulant dosages during jar stirring tests may generally improve the removal of problem-causing algae, such as C. hirundinella cells. Improved algal removal efficiencies will subsequently ensure final water with good aesthetic quality. The surface charge (zeta potential) on C. hirundinella cells can be used to evaluate the best coagulation conditions within an operating window of -10 mV to +3 mV when dosing various coagulants. Scanning electron microscopy investigations revealed major damaging effects to C. hirundinella cells when dosing high Ca(OH)2 concentrations. However, when dosing lower Ca(OH)2 concentrations, in combination with organic polymer, better C. hirundinella cell removal efficiencies with less damaging effects to cells was observed. This study also indicated that the pre-chlorination, without causing cell lyses, can be applied to render the highly motile cells immobile which will subsequently assist the coagulation unit process. The aesthetic quality (e.g. tastes and odours) of drinking water may be influenced when C. hirundinella cells release organic material into the water as a result of cell lyses. Organic compounds, such as fatty acids and dicarboxylic acids can lead to taste and odour problems which associate with the presence of C. hirundinella. Organic compounds also serve as precursors for the formation of harmful chlorine by-products formed during chlorination. / PhD (Environmental Sciences), North-West University, Potchefstroom Campus, 2015

Water quality and space constraints have become major concerns regarding the No. 7 waste water dam at Petra Diamonds’ Cullinan mine. The unique location of the dam constrains further development, while unsustainable accumulation of waste water inside the dam increases the risk of potential environmental contamination from seepages and spillages. The dam retains a significant amount of very poor quality water. Its excessively high pH, dissolved salt content, density and extreme turbidity result from the concentration of natural weathering products of the diamond bearing kimberlite ore. The turbidity results from the dispersion of colloidal chlorite, saponite and nontronite clay. Along with the chemistry of the solution, their colloidal shape contributes equally significantly to the non-settlement of these suspended clays. Flocculation of the dispersed clay particles will provide (a) for easy and effective separation of the clay material from the waste water and (b) more convenient options for water treatment (and subsequent redistribution) This study was aimed at contributing to a better understanding of the dynamic interactions in the No 7 Dam system to contribute towards identifying a suitable means/method for chemical flocculation of the clay particles. The individual components of the system (clays, water quality) and influx contributors (kimberlite and its leachate) were systematically characterized by means of X-Ray Diffraction, X-Ray Fluorescence, petrographic microscopy, electron microscopy, electrophoretic mobility and standard water- and soil quality analyses. The baseline quality of the Cullinan kimberlite leachate was obtained based on ASTM D5744 principles. It was found that adjusting the pH-level and ionic strength of the waste water to the critical coagulation point (cK) (as determined by electrophoretic mobility and batch jar experiments) automatically induced coagulation. Higher valence cations were displaced from pH dependent surface charge sites by proton adsorption. The resultant increased ionic strength, in combination with decreased thickness of the ionic double layer, was sufficient for the automatic initiation of high strength disordered face-face and edge-face bonds. During batch Jar tests, flocculation initiated within 4 minutes after the addition of HCl (0.5 M) and total sedimentation completed within 3 hours. The use of commercial flocculants might decrease the sedimentation time. As expected a significant increase in dissolved salt content of the clear supernatant was observed. No re-dispersion of the dried clay occurred. Throughout the study geochemical modeling was performed with PHREEQC software to identify/determine possible effective experimental conditions, minimizing experimental time and expenses. The program was also used to model outcomes of the possible water treatment options, indicated in literature as viable options for similar situations. These options can be tested to extend upon the current research. / MSc (Environmental Sciences), North-West University, Potchefstroom Campus, 2015

The freshwater dinoflagellate species, Ceratium hirundinella (C. hirundinella) possesses unique characteristics, such as a thecal-plate cell covering of cellulose, spines and flagella. Unlike most other algae and cyanobacteria, C. hirundinella cells are relatively large in size (up to 450 μm in length and 50 μm in width). These unique characteristics (e.g. cell covering and flagella) and adaptations (e.g. spines) give the dinoflagellate cells the ability to reduce their sinking rate from the euphotic zone and to migrate easily through the water column. When source water contains high concentrations of C. hirundinella cells, water treatment problems and poor aesthetic water quality can be expected. These water treatment problems may include 1) the disruption of coagulation and flocculation, 2) clogging of sand filters and 3) taste and odour problems when cells penetrate into the final water. In Chapter 9 of this study, a list of operational guidelines (including alert levels) and recommendations to assist managers and operators of plants when C. hirundinella cells are causing water treatment problems. During events of high C. hirundinella concentrations in source water, managers and operators of conventional water treatment plants need strategies to optimize coagulants and unit processes. Thus when source water contains motile nuisance algae, such as C. hirundinella, in moderate or abundant quantities, it is advisable to conduct jar stirring test experiments using both turbidity and total photosynthetic pigment (or chlorophyll-a) analyses as indicators of appropriate coagulant choice and dosages. The aims of this study are summarized as follows:  To optimize coagulants and conventional water treatment processes by implementing relevant algal removal strategies and indicators during jar stirring test experiments,  To investigate the changes in surface charge (known as zeta potential) on C. hirundinella cells before and after adding coagulants as part of the treatment processes,  To investigate the physical and chemical impacts on the morphology of C. hirundinella cells after coagulation, flocculation and sedimentation,  To identify organic compounds that may be responsible for taste and odour problems associated with C. hirundinella,  To investigate the efficiency of pre-chlorination on the removal C. hirundinella cells when dosing various coagulants, and  Give recommendations and operational guidelines relevant for a conventional water treatment plant to improve C. hirundinella removal A combined water treatment system (Phipps and Bird Model), consisting of a six paddle jar test apparatus and six sand filter columns, was used to simulate conventional processes (coagulation, flocculation, sedimentation and rapid sand filtration). Source water samples containing relatively high C. hirundinella concentrations (> 500 cell/mℓ) were collected from Benoni Lake (26º10’50.40’’S; 28º17’50.11’’ E) in plastic containers and stored as a homogenous sample in a 200 litre container under laboratory conditions (± 22 °C). Samples were collected from the source water as well as after sedimentation (from the supernatant or sludge) to determine turbidity, total photosynthetic pigment analyses (chlorophyll) and for phytoplankton analyses. Flocs (containing C. hirundinella cells) were collected from the sludge or sediment for scanning electron microscopy investigations and to perform zeta potential analyses. Concentrated C. hirundinella samples were frozen at -80 °C according to the proposed sampling protocol for organic compound analyses. Results obtained from this study proved that using the relevant indicators to determine the appropriate coagulant dosages during jar stirring tests may generally improve the removal of problem-causing algae, such as C. hirundinella cells. Improved algal removal efficiencies will subsequently ensure final water with good aesthetic quality. The surface charge (zeta potential) on C. hirundinella cells can be used to evaluate the best coagulation conditions within an operating window of -10 mV to +3 mV when dosing various coagulants. Scanning electron microscopy investigations revealed major damaging effects to C. hirundinella cells when dosing high Ca(OH)2 concentrations. However, when dosing lower Ca(OH)2 concentrations, in combination with organic polymer, better C. hirundinella cell removal efficiencies with less damaging effects to cells was observed. This study also indicated that the pre-chlorination, without causing cell lyses, can be applied to render the highly motile cells immobile which will subsequently assist the coagulation unit process. The aesthetic quality (e.g. tastes and odours) of drinking water may be influenced when C. hirundinella cells release organic material into the water as a result of cell lyses. Organic compounds, such as fatty acids and dicarboxylic acids can lead to taste and odour problems which associate with the presence of C. hirundinella. Organic compounds also serve as precursors for the formation of harmful chlorine by-products formed during chlorination. / PhD (Environmental Sciences), North-West University, Potchefstroom Campus, 2015