As cianotoxinas, potencialmente prejudiciais à saúde dos homens e animais, são toxinas produzidas pelas cianobactérias e que podem estar presentes em reservatórios utilizados para captação de água para abastecimento, sobretudo em função do agravamento das condições sanitárias das bacias hidrográficas. Diante disso, torna-se fundamental que a água esteja adequada ao consumo humano em sua distribuição. Uma das formas de tratamento para remoção das cianotoxinas que vem sendo estudada é por meio do uso de carvão ativado granular (CAG), cuja eficiência depende de suas características intrínsecas e das condições operacionais. Outra possibilidade para remoção de tais toxinas se dá por meio da utilização de microrganismos capazes de promover sua biodegradação. A presente pesquisa analisou o potencial de remoção de microcistina por meio de adsorção por três diferentes CAGs comerciais (materiais de origem: casca de coco, mineral e osso) e por meio da degradação biológica por dois gêneros de bactérias. Para isso, foi utilizado um extrato de toxina produzido por meio do cultivo de Microcystis aeruginosa (cepa BB005) em meio WC, ao longo de 30 dias, com fotoperíodo de 12 h. Os carvões foram caracterizados de acordo com a massa específica aparente, umidade, pH, teor de cinzas, número de iodo, índice de azul de metileno e área superficial específica. Em seguida, foram realizados ensaios de adsorção com a microcistina (concentração inicial de 100 µg.L-1) para construção de isotermas com tempo de equilíbrio de 1 h. As análises de toxina foram realizadas pelo método ELISA e os dados foram ajustados aos modelos matemáticos de Langmuir e de Freundlich. Os melhores resultados de adsorção foram obtidos a partir do carvão de origem mineral (99% de remoção), que apresentou valores maiores para número de iodo (710 mgI2.g-1), índice de azul de metileno (169 mL.g-1), área superficial específica (911 m2.g-1) e porcentagem de microporos (70%), com melhor ajuste da isoterma obtido pelo modelo de Freundlich (R2 = 0,88). Os ensaios de biodegradação da microcistina com os gêneros Sphingomonas sp. e Brevundimonas sp foram realizados com a toxina esterilizada e não esterilizada (concentração inicial de 75 µg.L-1). Os resultados demonstraram que tais bactérias não foram capazes de degradar a toxina esterilizada. Entretanto, foi observada degradação nos ensaios em que a toxina não estava esterilizada (porcentagem de remoção de 98%), indicando a presença de algum microrganismo e/ou enzima atuante nesse processo, uma vez que o cultivo da cepa para obtenção do extrato não foi realizado sob condições de assepsia. Recomenda-se, para futuras pesquisas, a identificação do responsável pela biodegradação da microcistina, bem como a aplicação do carvão mineral em maior escala (filtro de leito fixo). Deste modo, será possível avaliar a formação de biofilme no leito de carvão, e comparar o desempenho da adsorção e da biodegradação na remoção do poluente-alvo em escala mais próxima à real. / The cyanotoxins, which are potentially harmful to the health of humans and animals, are toxins produced by cyanobacteria. They can be found in reservoirs used for water supply, especially due to the degradation of sanitary conditions within the watersheds. Therefore, it is essential to assure potable water for human consumption in its distribution. The use of granular activated carbon (GAC) has been studied for advanced water treatment and cyanotoxins\' removal. The efficiency of such technology depends on activated carbon intrinsic characteristics and operating conditions. Removing such toxins through biodegration by microrganisms is another possibility. The present study was perfomed in laboratory conditions and analyzed microcystin removal by adsorption by three commercial GACs (source materials: coconut shell, mineral and bone) and through the biological degradation by two genera of bacteria. An extract of toxin was produced by the cultivation of Microcystis aeruginosa (strain BB005), in medium WC throughout 30 days, with a 12 h photoperiod. The activated carbon samples were characterized regarding the apparent density, moisture, pH, ash content, iodine number, methylene blue index and specific surface area. Thereafter, adsorption experiments were conducted with microcystin (initial concentration of 100 µg.L-1) for estimating isotherms considering an equilibrium time of 1 h. The toxin analyses were performed by the ELISA (Enzyme-Linked Immunosorbent Assay) and the data were adjusted to the mathematical models of Langmuir and Freundlich. The best adsorption results were obtained with the mineral carbon (removal percentages of 98%), which also showed the highest values for the iodine number (710 mgI2.g-1), methylene blue index (169 mL.g-1), specific surface area (911 m2.g-1) and percentage of micropores (70%), with best adjustment of the isotherm through the Freundlich model (R2 = 0.88). The biodegradation tests of microcystin with Sphingomonas sp. and Brevundimonas sp. were carried out with the sterile and non-sterile toxin (initial concentration of 75 µg.L-1). The results showed that these bacteria were not able to promote degradation of the toxin when it was sterilized. However, the degradation was observed in those tests in which the toxin was not sterilized (reduction up to 98%), suggesting the presence of a microrganism and/or an enzyme responsible for this process, since the cultivation of the strain for obtaining the extract was not performed under sterile conditions. As for future research, it is recommendedthe identification of the factor responsible for the biodegradation of the microcystin, as well as the study of the use of the activated carbon from mineral source in a larger scale (fixed-bed filter). This would help to reach a scale closer to the real water treatment plants and evaluate the biofilm formation in the carbon bed, allowing the comparison of the performance of both adsorption and biodegradation processes in the removal of the target pollutant.

Water supply systems aim, among other objectives, to protect public health by reducing the concentration of, and potentially eliminating, microorganisms pathogenic to human beings. Yet, because water supply systems are engineered systems facing variable conditions, such as raw water quality or treatment process performance, the quality of the drinking water produced also exhibits variability. The reliability of a treatment system is defined in this context as the probability of producing drinking water that complies with existing microbial quality standards. This thesis examines the concept of reliability for two physicochemical treatment technologies, conventional rapid granular filtration and ultrafiltration, used to remove the protozoan pathogen Cryptosporidium parvum from drinking water. First, fault tree analysis is used as a method of identifying technical hazards related to the operation of these two technologies and to propose ways of minimizing the probability of failure of the systems. This method is used to compile operators’ knowledge into a single logical diagram and allows the identification of important processes which require efficient monitoring and maintenance practices. Second, an existing quantitative microbial risk assessment model is extended to be used in a reliability analysis. The extended model is used to quantify the reliability of the ultrafiltration system, for which performance is based on full-scale operational data, and to compare it with the reliability of rapid granular filtration systems, for which performance is based on previously published data. This method allows for a sound comparison of the reliability of the two technologies. Several issues remain to be addressed regarding the approaches used to quantify the different input variables of the model. The approaches proposed herein can be applied to other water treatment technologies, to aid in prioritizing interventions to improve system reliability at the operational level, and to determine the data needs for further refinements of the estimates of important variables. / Applied Science, Faculty of / Civil Engineering, Department of / Graduate

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Submitted master's thesis is dealing with the problem of occurrence of residues of specific anthropogenic pollution of drinking water sources, with accent on possibilities of elimination of these compounds during drinking water treatment. There was pay attention to two estrogenic hormones – estradiol and ethinylestradiol. In laboratory scale there was tested efficiency of coagulation, activated carbon adsorption and ozonation in elimination of studied compounds from artificially contaminated water.

Drinking water treatment is facing an adverse impact of algae especially when they extensively decay and release cellular organic matter (COM). As the character and consequently the removal efficacy of COM depends on the individual species, the thesis compares algal organic matter (AOM) derived from four common phytoplankton species: green alga Chlamydomonas geitleri, diatom Fragilaria crotonensis, and cyanobacteria Microcystis aeruginosa and Merismopedia tenuissima. To evaluate the differences between extracellular and cellular organic matter, we monitored the growth of those organisms and compared AOM obtained at different growth phases. As COM is not only difficult to coagulate, but also hinders the coagulation of other substances, the thesis investigates the effect of simultaneous coagulation of COM with other impurities present in surface waters: kaolin, humic substances (HS) or cyanobacterial cells of M. tenuissima. Coagulation behaviour was studied by the jar tests performed with single components and their mixtures with and without a coagulant (ferric or aluminium sulphate). Special emphasis was paid to proteinaceous COM of M. aeruginosa; to enhance the removability of proteinaceous matter we implemented pre-oxidation. Coagulation effectively removed turbidity (up to 99%) either of clay or...

The aim of this master’s thesis was to investigate if defattening of Parkinsonia aculeata (in swahili “mkeketa”) and Vigna unguiculata (in swahili “choroko”) would enhance the capacity of the seed’s properties in removing suspended particles from surface water. The seeds are used in local traditional treatment of drinking water in Tanzania. The aim was also to investigate the possibility to reduce high concentrations of fluoride with the seeds. The seeds contain proteins that act as coagulants. Coagulated particulate matter can be flocculated and separated from the water. A purification of the coagulants by defattening was expected to enhance the coagulating capacity. Experiments were conducted in jar-tests with dosages of coagulant solutions of undefattening and defattened seed solutions and alum (aluminium sulphate). The experiments showed that both Parkinsonia aculeata and Vigna unguiculata seeds can compete with alum in drinking water treatment of surface water, reaching the same or better final results in turbidity removal. Both seeds also produce less sludge volumes than alum and functions in turbidity removal together with alum. The seeds may be used as coagulant aids to reduce the usage of chemicals and sludge production. They were not able to clarify turbid waste water and did not reduce high concentrations of fluoride in groundwater. Further, the turbidity-removal capacity of the coagulants had reduced capacities in water with low pH-values.

The removal of 34 per- and polyfluoroalkyl substances (PFAS) were compared in a 1 stagegranular activated carbon (GAC) filtration to a 2 stage GAC filtration in a pilot study at adrinking water treatment plant (DWTP). The PFASs that were present in the water wereperfluorooctanoic acid (PFOA), perfluorooctane sulfonic acid (PFOS), perfluoropentanoic acid(PFPeA), perfluorohexanoic acid (PFHxA), perfluoroheptanoic acid (PFHpA), perfluorobutanesulfonic acid (PFBS), perfluoropentane sulfonic acid (PFPeS) and perfluorohexane sulfonic acid(PFHxS). A cost comparison for the operation of a one stage GAC to a two stage GAC wascompared for PFAS4 (sum of PFOA, PFNA, PFHxS and PFOS) at treatment goals ranging from2 - 10 ng/L. The pilot was operated at three different flows and the three different bed volumes(BV)s resulting in three different empty bed contact times (EBCTs) at three different times.Therefore, the Lin & Huang adsorption model (1999) was used to model the concentrations ateach EBCT. It was found that the model worked good for PFBS, PFPeS, PFHxS, PFOS andPFOA but not for PFPeA, PFHxA and PFHpA (except for PFPeA and PFHxA during EBCT 5min) and did not work for desorbing PFASs. The removal comparison of PFASs was made,partly by comparing removal efficiencies between the first stage and the second stage GAC filterand by comparing the removal per weight of GAC per BV 1 stage and 2 stages. It was found thatthe removal efficiency decreases with decreasing chain length and increasing treated BVs forboth the first stage and the second stage. The short chain PFCAs were also desorbing after anumber of BVs. The removal per weight of GAC showed that the removal does not increasewhen comparing a one stage GAC to a two stage GAC for any the PFAS. The cost comparisonwas made using the adsorption model. It showed that it was cheaper to operate a 2 stage GAC forthe EBCT of 5 minutes and 8 minutes for the whole range of treatment goals. However, for theEBCT of 15 minutes the costs for the second stage was decreasing with decreasing treatmentgoal which is unrealistic result. This was caused by too few data points available for the model topredict reliable results.

Protecting drinking water supplies from pathogens such as Cryptosporidium parvum is a major concern for water treatment plants worldwide. The sensitivity and specificity of current detection methods are largely determined by the effectiveness of the concentration and separation methods used. In this study, disposable microfluidic micromixers were fabricated to effectively isolate Cryptosporidium parvum Oocysts from water samples, while allowing direct observation of Oocysts captured in the device using high quality immunofluorescence microscopy. In parallel, quantitative analysis of the capture yield was carried out by analyzing the waste from the microfluidics outlet with an Imaging Flow Cytometer. At the optimal flow rate, capture efficiencies higher than 95% were achieved in spiked samples, suggesting that scaled microfluidic isolation and detection of Cryptosporidium parvum will provide a faster and more efficient detection method for Cryptosporidium compared to other available laboratory-scale technologies.

No description available.

No / Organic matter (OM) causes many problems in drinking water treatment. It is difficult to monitor OM concentrations and character during treatment processes due to its complexity. Fluorescence spectroscopy is a promising tool for online monitoring. In this study, a unique dataset of fluorescence excitation emission matrixes (EEMs) (n = 867) was collected from all treatment stages of five drinking water treatment plants (WTPs) situated in diverse locations from subtropical to temperate climate. The WTPs incorporated various water sources, treatment processes and OM removal efficiencies (DOC removal 0%–68%). Despite these differences, four common fluorescence PARAFAC components were identified for characterisation of OM concentration and treatability. Moreover, fluorescence component ratios showed site-specific statistically significant correlations with OM removal, which contrasted with correlations between specific UV absorbance at 254 nm (SUVA) and OM removal that were not statistically significant. This indicates that use of fluorescence spectroscopy may be a more robust alternative for predicting DOC removal than UV spectroscopy. Based on the identified fluorescence components, four optical locations were selected in order to move towards single wavelength online OM monitoring.