WATER TREATABILITY STUDIES OF PARAIBA DO SUL RIVER WHICH SUPLLY SÃO JOSÉ DOS CAMPOS/SP CITY

Abstract

This paper presents the results of a study on the behavior of two coagulants, aluminium sulfate and Fenton's reagent, on the water treatment in a medium sized city in Sao Paulo State, Brazil. The water sample was collected in two different seasonal periods: wet and dry. It was varied dosages and their respective coagulation pH values and the coagulation diagrams were stablished, in order to choose the most appropriate pair of values ‘coagulant dosage versus coagulation pH’ taking into account the turbidity removal. The results shown that the Fenton's reagent was more efficient in removing turbidity, during the analysis of the diagrams and after the addition of cationic polymer and filtration, and indeed, it has provided lower concentrations of trihalomethanes at the end of treatment. However, with aluminium sulfate all mesuared parameters were below the Brazilian drinking water standard. The comparison has pointed out that either aluminium sulfate or Fenton's reagent can be used to treat the water samples from Paraiba do Sul river.

Key Words: Coagulation diagrams, Fenton’s reagent, THM, treatability studies.