O aumento da incidência de florações de cianobactérias potencialmente tóxicas nos mananciais de abastecimento, favorecidas pelo elevado aporte de nutrientes nos corpos d\'água, compromete a qualidade da água de consumo e põe em risco a saúde humana e animal, além de elevar os custos do tratamento de água. A pré-cloração, tem se mostrado uma ótima opção tanto na inativação de cianobactérias como na remoção de cianotoxinas dissolvidas. No entanto, sob certas condições, pode causar lise celular e promover a liberação das toxinas no meio. O objetivo deste trabalho foi avaliar em escala laboratorial, o efeito da pré-cloração, utilizando como agente oxidante o hipoclorito de sódio, sobre a integridade celular de uma linhagem tóxica de Microcystis aeruginosa (LTPNA 08), por citometria de fluxo, e sobre a subsequente liberação e degradação das microcistinas (LR e RR) por LC-MS/ MS. Diferentes dosagens de cloro (0,05, 0,5, 1, 1,5, 2, 2,5, 3, 4 e 8 mg.L-1), tempos de contato (0, 15, 30 e 60 minutos) e densidade celular (1x106 células.mL-1 para os ensaios de jarros e 3,5 x106 células.mL-1 para o ensaio de viabilidade celular) foram utilizadas neste estudo. Os resultados obtidos nos ensaios de jarros mostraram remoções de microcistinas acima de 70% após 60 minutos de exposição ao oxidante, com 100% de remoção em doses de 2,5 e 3 mg Cl2.L-1. Valores de CT (concentração x tempo) acima de 40,66 mg.min.L-1 foram necessários para degradar as microcistinas a concentrações abaixo de 1,0 µg.L-1, exigidos pela organização mundial de saúde (WHO) e pela legislação brasileira de potabilidade da água (Portaria MS nº 2914/2011). Não foi possível verificar a lise celular por microscopia óptica, no entanto, na análise por HPLC-DAD verificou-se degradação de mais de 70% da clorofila-a em todas as dosagens testadas, após 60 minutos de exposição, com a completa degradação nas concentrações de 2,5 e 3 mg.L-1 Cl2, indicando dano celular. Nos ensaios por citometria de fluxo, foi verificada a perda da integridade celular com o aumento da dosagem de cloro aplicada, observando-se a permeabilidade celular máxima, sem a desintegração da célula, na concentração de 2,5 mg.L-1 Cl2. Concentrações de 4 e 8 mg.L1 Cl2 promoveram a lise total das células, impossibilitando a permanência do marcador na célula. A perda dos pigmentos clorofila a e ficocianina ocorreram em concentrações de acima de 2,5 e acima de 1,5 mg.L-1 Cl2, respectivamente. O presente trabalho reforçou a eficiência da cloração na degradação das toxinas e os resultados obtidos podem ajudar as autoridades competentes a otimizar as práticas de cloração utilizadas no pré-tratamento da água. / The increased incidence of blooms of potentially toxic cyanobacteria in supply sources, favored by high input of nutrients in water bodies, compromises the quality of drinking water and affect human and animal health, besides increasing water treatment costs. The pre-chlorination, has proved a great choice both in the inactivation of cyanobacterial cells as in removing dissolved cyanotoxins. However, under certain conditions, can cause cell lysis and release toxins. The objective of this study was to evaluate in laboratory scale, the effect of pre-chlorination, using sodium hypochlorite, on cell integrity of toxic Microcystis aeruginosa (LTPNA 08) using flow cytometry, and the subsequent release and degradation of microcystins (LR and RR) by LC-MS / MS. Different chlorine doses (0.05, 0.5, 1, 1.5, 2, 2.5, 3, 4 and 8 mg.L-1), contact times (0, 15, 30 and 60 minutes) and cell density (1x106 células.mL-1 for jar-test and 3.5 x106 células.mL-1 for cell viability assay) were used in this study. The results obtained in the jar- test showed degradations up to 70% after 60 minutes of exposure, with complete degradation at chlorine doses of 2,5 e 3 mg.L-1. Chlorine exposure (CT) values over 40,66 mg.min.L-1 were required for oxidation of microcystin LR and RR to concentrations below the World Health Organization (WHO) and Brazilian legislation for water potability (Portaria MS nº 2914/2011) guideline value of 1µg.L-1. No differences in cell number was observed by microscopy, however, analysis by HPLC-DAD found chlorophyll-a reductions of more than 70% in all dosages tested after 60 minutes exposure, with values below the limit of quantification for concentrations of 2.5 and 3 mg.L-1 Cl2, indicating cell damage. In assays using flow cytometry, loss of cell integrity was observed with increasing chlorine concentration. The maximum cell permeability without cell disintegration was observed at a concentration of 2.5 mg.L-1 Cl2. Concentrations of 4 and 8 mg.L-1 Cl2 lead to complete cell lysis, making impossible the permanence of SYTOX Green in the cell. The loss of pigment chlorophyll a and phycocyanin occurred in concentrations above 2.5 and 1.5 mg.L-1 Cl2, respectively. This study reinforced the efficiency of chlorination in the toxins degradation and the results can help the water authorities to optimize the chlorination practices used in the pretreatment of water.

O aumento da incidência de florações de cianobactérias potencialmente tóxicas nos mananciais de abastecimento, favorecidas pelo elevado aporte de nutrientes nos corpos d\'água, compromete a qualidade da água de consumo e põe em risco a saúde humana e animal, além de elevar os custos do tratamento de água. A pré-cloração, tem se mostrado uma ótima opção tanto na inativação de cianobactérias como na remoção de cianotoxinas dissolvidas. No entanto, sob certas condições, pode causar lise celular e promover a liberação das toxinas no meio. O objetivo deste trabalho foi avaliar em escala laboratorial, o efeito da pré-cloração, utilizando como agente oxidante o hipoclorito de sódio, sobre a integridade celular de uma linhagem tóxica de Microcystis aeruginosa (LTPNA 08), por citometria de fluxo, e sobre a subsequente liberação e degradação das microcistinas (LR e RR) por LC-MS/ MS. Diferentes dosagens de cloro (0,05, 0,5, 1, 1,5, 2, 2,5, 3, 4 e 8 mg.L-1), tempos de contato (0, 15, 30 e 60 minutos) e densidade celular (1x106 células.mL-1 para os ensaios de jarros e 3,5 x106 células.mL-1 para o ensaio de viabilidade celular) foram utilizadas neste estudo. Os resultados obtidos nos ensaios de jarros mostraram remoções de microcistinas acima de 70% após 60 minutos de exposição ao oxidante, com 100% de remoção em doses de 2,5 e 3 mg Cl2.L-1. Valores de CT (concentração x tempo) acima de 40,66 mg.min.L-1 foram necessários para degradar as microcistinas a concentrações abaixo de 1,0 µg.L-1, exigidos pela organização mundial de saúde (WHO) e pela legislação brasileira de potabilidade da água (Portaria MS nº 2914/2011). Não foi possível verificar a lise celular por microscopia óptica, no entanto, na análise por HPLC-DAD verificou-se degradação de mais de 70% da clorofila-a em todas as dosagens testadas, após 60 minutos de exposição, com a completa degradação nas concentrações de 2,5 e 3 mg.L-1 Cl2, indicando dano celular. Nos ensaios por citometria de fluxo, foi verificada a perda da integridade celular com o aumento da dosagem de cloro aplicada, observando-se a permeabilidade celular máxima, sem a desintegração da célula, na concentração de 2,5 mg.L-1 Cl2. Concentrações de 4 e 8 mg.L1 Cl2 promoveram a lise total das células, impossibilitando a permanência do marcador na célula. A perda dos pigmentos clorofila a e ficocianina ocorreram em concentrações de acima de 2,5 e acima de 1,5 mg.L-1 Cl2, respectivamente. O presente trabalho reforçou a eficiência da cloração na degradação das toxinas e os resultados obtidos podem ajudar as autoridades competentes a otimizar as práticas de cloração utilizadas no pré-tratamento da água. / The increased incidence of blooms of potentially toxic cyanobacteria in supply sources, favored by high input of nutrients in water bodies, compromises the quality of drinking water and affect human and animal health, besides increasing water treatment costs. The pre-chlorination, has proved a great choice both in the inactivation of cyanobacterial cells as in removing dissolved cyanotoxins. However, under certain conditions, can cause cell lysis and release toxins. The objective of this study was to evaluate in laboratory scale, the effect of pre-chlorination, using sodium hypochlorite, on cell integrity of toxic Microcystis aeruginosa (LTPNA 08) using flow cytometry, and the subsequent release and degradation of microcystins (LR and RR) by LC-MS / MS. Different chlorine doses (0.05, 0.5, 1, 1.5, 2, 2.5, 3, 4 and 8 mg.L-1), contact times (0, 15, 30 and 60 minutes) and cell density (1x106 células.mL-1 for jar-test and 3.5 x106 células.mL-1 for cell viability assay) were used in this study. The results obtained in the jar- test showed degradations up to 70% after 60 minutes of exposure, with complete degradation at chlorine doses of 2,5 e 3 mg.L-1. Chlorine exposure (CT) values over 40,66 mg.min.L-1 were required for oxidation of microcystin LR and RR to concentrations below the World Health Organization (WHO) and Brazilian legislation for water potability (Portaria MS nº 2914/2011) guideline value of 1µg.L-1. No differences in cell number was observed by microscopy, however, analysis by HPLC-DAD found chlorophyll-a reductions of more than 70% in all dosages tested after 60 minutes exposure, with values below the limit of quantification for concentrations of 2.5 and 3 mg.L-1 Cl2, indicating cell damage. In assays using flow cytometry, loss of cell integrity was observed with increasing chlorine concentration. The maximum cell permeability without cell disintegration was observed at a concentration of 2.5 mg.L-1 Cl2. Concentrations of 4 and 8 mg.L-1 Cl2 lead to complete cell lysis, making impossible the permanence of SYTOX Green in the cell. The loss of pigment chlorophyll a and phycocyanin occurred in concentrations above 2.5 and 1.5 mg.L-1 Cl2, respectively. This study reinforced the efficiency of chlorination in the toxins degradation and the results can help the water authorities to optimize the chlorination practices used in the pretreatment of water.

abstract: Specific inorganic and organic pollutants in water (As(V), Cr(VI), THMs, and hardness) cause health concerns or aesthetic problems. The goal of this dissertation is to demonstrate novel approaches to improve the performance of point of use and municipal activated carbon processes to provide safe and reliable water to the public at distributed centralized locations. Template Assisted Crystallization system would adjust saturation index (SI) value of TAC treated water to zero when SI value of influent water was in the range at 0.08~0.3. However, the reduction in SI when SI values were higher (e.g. 0.7~1.3) was similar to the reduction at lower SI values which could be due to limitations in kinetics or mass transfer with the template on TAC media. Pre-chlorination prior to municipal-scale granular activated carbon (GAC) treatment was evaluated to control THM formation in distribution systems. Pre-chlorination decreased UVA, shift the dissolved organic carbon (DOC) molecular weight distribution and pre-formed trihalomethanes (THM). GAC treatment of pre-chlorinated water achieved lower THM formation in distribution systems. To add functionality in POU systems to remove As(V) and Cr(VI), activated carbon was nano-tized to fabricate nano-enabled carbon block (CB) by (1) impregnating iron or titanium metal oxides chemically or (2) attaching titanium based P25 through electrostatic attraction force. Nanoparticle loadings of 5 to 10 wt % with respect to activated carbon enables reduction of As(V) or Cr(VI) from levels of common occurrence to below regulatory levels across carbon block designs. Minimal impacts on As(V) and Cr(VI) sorption were observed up to a nanoparticle pre-treatment temperature of 200 C, which is the temperature for CB production. Through controlling pH at 4.5 during mixing of nanoparticles with pH IEP=6 and activated carbon with pH IEP=3, electrostatic attachment of nanoparticles to activated carbon could be achieved prior to fabricating carbon block. A mini carbon block test device was designed, fabricated, and validated to mimic performances of full-scale carbon block using less volumes of test water. As(V) removal tests showed Fe impregnated CB achieved the highest As(V) removal while P25 attached CB had the lowest among three nanoparticles loaded CBs. / Dissertation/Thesis / Doctoral Dissertation Civil, Environmental and Sustainable Engineering 2018

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

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