Remoção de cianobactérias no tratamento de água eutrofizada utilizando dupla filtração e oxidação

Resumen

The objective of this work was to evaluate the cyanobacteria cells removal in the treatment of raw water stored in dams submitted to eutrophication processes, through double filtration, using Poly Aluminum Chloride and cationic polymer as coagulants, and oxidation with chlorine, chlorine dioxide and potassium permanganate. A pilot installation formed by 4 pairs of filters, simultaneously operated was used. The filtration runs were carried out using equal dosages of coagulants. To evaluate the effect of the oxidants, the first pair of filters did not receive oxidant, in the second pair was applied a dosage of 2,0 mg/L of chlorine, the third received a dosage of 1,0mg/L of chlorine dioxide and the last one was operated with a dosage of 0,25mg/L of potassium permanganate. The oxidants were applied either before the upflow filters or between the filters. The results showed that a cyanobacteria cells removal above 99.9% could de achieved through double filtration treatment. The use of chlorine and chlorine dioxide increased the removal of cyanobacteria cells. No advantages of algal cells removal was observed by the aplication of potassium permanganate, probably due to insufficient dosages.