Removal of microcystins in water from eutrophic reservoir involving technical of clarification, pre-oxidation with potassium permanangate, adsorption with powdered activated carbon and post-chlorination / Remoção de microcistina em águas provenientes de reservatório eutrofizado associando técnicas de clarificação, pré-oxidação com permanganato de potássio, adsorção em carvão ativado e pós-cloração

AUTOR(ES)
DATA DE PUBLICAÇÃO

2009

RESUMO

The present work had as objective to evaluate the removal of three different concentrations of extracellular microcystins in different combinations of water treatment for supplying, in bench scale, that had as basic sequence the clarification associated or not with the processes of pre-oxidation with KMNO IND.4, adsorption on PAC and post-chlorination. The results showed that for all waters studied the potassium permanganate did not interfere in the mechanisms of coagulation/flocculation and also proved to be a safe alternative for achieving the pre-oxidation with regard to the formation of THMs. In Phase 1, with initial concentration of extracellular microcystin around 1.4 müg/L, the clarification (coagulation, flocculation, dissolved air flotation and clarification final) met the World Health Organization drinking water guideline value of 1.0 müg/L of microcystin. Already, in Phase 2, with initial concentration extracellular microcystin around 21.7 müg/L, to meet the legislation was necessary to involved the clarification with the pre-oxidation, dosing 1.0 or 2.0 mg KMNO IND.4/L, and with the post-chlorination with 3.0 mg CL IND.2/L. In Phase 3, with initial concentration of extracellular microcystin around 64.1 müg/L, the association of clarification with the adsorption with 60.0 mg/L of PAC and the post-chlorination with 3.0 mgCL IND.2/L provided residual extracellular microcystin below 1.0 müg/L. It was also observed that in Phases 1 and 3 the presence of dissolved organic matter intervened negatively in the sequence of treatment when consuming part of the potassium permanganate destined to the oxidation of extracellular microcystin. However, in Phase 2 the demand for pre-oxidizing by the humic substances seems to have prevented the lysis of some cells of Microcystis sp.

ASSUNTO(S)

permanganato de potássio tratamento de água carvão ativado em pó microcystin trihalomethanes pós-cloração substâncias húmicas adsorção pré-oxidação post-chlorination water treatment trihalometanos humic substances preoxidation microcistina powdered activated carbon potassium permanganate adsorption

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