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A Deus e a todos os santos que sempre estiveram ao meu lado.

In this study a poorly biodegradable (BOD/COD = 0.3) industrial alkaline ECF bleaching filtrate was treated using different advanced oxidation processes to evaluate their use in combined chemical-biological treatment aimed at increasing recalcitrant COD removal and improving final effluent quality. Oxidative treatments included ozonation combined with hydrogen peroxide (2, 5, 10, 20 mmol L(-1) O3/0.7, 2, 5, 10 mmol L(-1) H2O2) and photocatalysis with hydrogen peroxide (UV/2, 4 and 8 mmolL(-1) H2O2) and with TiO2 (UV/TiO2/0.7 and 4 mmol L(-1) H2O2). The O3/H2O2 process increased effluent biodegradability by up to 68% as a result of increasing BOD and decreasing COD. Increasing the O3 dose had a greater effect on biodegradability improvement and lignin and colour removal efficiencies than increasing the H2O2 dose. A combined oxidant dose of 5 mmol L(-1) O3 and 2 mmol L(-1) H2O2 resulted in 75% lignin removal, 40% colour removal and 6% carbohydrate loss without mineralizing the organic carbon. The photocatalytic processes led to a decrease in effluent biodegradability through combined decrease in BOD and increase in COD and did not result in efficient lignin or colour removal. Photocatalytic oxidation was apparently inhibited by the high chloride and COD levels in the alkaline filtrate, and may be more efficient in recalcitrant COD removal if performed after biological.

ABSTRACT. Sewage disinfection has the primary objective of inactivating pathogenic organisms to prevent the dissemination of waterborne diseases. This study analyzed individual disinfection, with chlorine and ultraviolet radiation, and sequential disinfection (chlorine-UV radiation). The tests were conducted with anaerobic effluent in batch, in laboratory scale, with two dosages of chlorine (10 and 20 mg L ). In addition, to guarantee the presence of cysts in the tests, 10 4 cysts per liter of Giardia spp. were inoculated. The resistance order was as follows: E. coli = Total Coliforms < Clostridium perfringens < Giardia spp.. Furthermore, synergistic effects reached 0.06 to 1.42 log of inactivation in sequential disinfection for both the most resistant microorganisms.Keywords: chlorine, ultraviolet radiation, Giardia, Clostridium perfringens, total coliforms, synergism.Estudo de desinfecção sequencial para inativação de protozoário e microrganismos indicadores em esgoto sanitário RESUMO. A desinfecção de esgoto sanitário tem o objetivo principal de inativar microrganismos patogênicos para combater a disseminação de doenças de veiculação hídrica. Este estudo analisou a desinfecção individual, com cloro e radiação ultravioleta, e a desinfecção sequencial (cloro -radiação UV). Os testes foram realizados com o efluente anaeróbio, em escala de bancada e em batelada, com duas doses de cloro (10 e 20 mg L -1 ) e duas doses de radiação UV (2.5 e 6.1 Wh m -3). Além disso, para os testes, a fim de garantir a presença de cistos, foram inoculados 10 4 cistos por litro de Giardia spp. A ordem de resistência foi a seguinte: E. coli = coliformes totais < Clostridium perfringens < Giardia spp. Além disso, na desinfecção sequencial para ambos os microrganismos mais resistentes, os efeitos sinérgicos alcançaram de 0,06 a 1,42 log de inativação.

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A Deus e a todos os santos que sempre estiveram ao meu lado.Agradeço a minha família, em especial aos meus pais, Nelson e Eva, minha vózinha Suely, que mesmo longe, sempre me deram suporte para trilhar o meu caminho. "Vim, vi e venci", novamente.

More precise methods are needed to recover Giardia and Cryptosporidium (oo)cysts from wastewater in order to advance research related to their inactivation, removal, quantification, and species differentiation. This study applied different methods to recover the maximum number of (oo)cysts from wastewater samples using ColorSeed®. Immunomagnetic separation assisted in capturing oocysts mainly in samples with medium and low turbidity. A triple centrifugation method reached recovery rates of 85% and 20%, for Giardia cysts and Cryptosporidium oocysts, respectively, in raw wastewater, and 62.5 and 17.5% in secondary-treated effluent. For low turbidity-treated effluent, membrane filtration reached 67.5% recovery for Giardia cysts and 22.5% for Cryptosporidium oocysts. Simple, quick and low-cost methods do not involve much handling of the samples and could be useful, particularly in developing countries.