Efficacy of two natural tannins-based polymers in contrast to aluminum sulfate for drinking water production

Abstract

The rapid population growth requires significantly increase of the water treatment rates with high efficiencies, larger amounts of aluminum sulfate, and higher volumes of both sludge and filter backwash water and increased of the treatment costs. It believed that replacing the aluminum sulfate for natural polymers is an alternative to improve the treatments and reduce risks related to the presence of aluminum ions in the processes of water production. In this study, raw water from a drinking water treatment company at southern Brazil were assessed in terms of treatment with two natural tannins-based polymers in contrast to a conventional aluminum sulfate (the classical metal salt for water clarification). Jar test studies were performed to removal of turbidity and color. The main results showed that low polymer concentration (15 ​mg/L) allowed up to 90% turbidity removal and 86% color removal. In addition, alkalinity, pH, electrical conductivity and organic matter content was not increased. If compared, the tannins-based polymers could replace the aluminum sulfate. Thus, it believed that this work contribute to research in the area of natural polymers to promote high clarification efficiencies and safety for health and environment.

Keywords

• Aggregation. coagulation. flocculation. drinking water treatment. tannin polymer. aluminum sulfate