Integration of ozonation with water treatment for pharmaceuticals removal from Arroio Diluvio in southern Brazil

Abstract

Pharmaceutical compounds can reach water bodies through sewage systems. The process of water treatment is insufficient for the removal of these contaminants. The ozonation has great potential to be integrated into the treatment, since it promotes the reduction of pharmaceuticals, reduces the generation of disinfection byproducts and can reduce operational costs. In this work, the integration of the ozonation process with water treatment was studied. The ozone was applied in the pre-oxidation and intermediate ozonation stages, to evaluate the dependence of different variables. Water samples were collected from Arroio Diluvio, a river of the city of Porto Alegre (Brazil). The doses of ozone were maintained between 0.5 and 1.0 mgO3 L−1 while the coagulant was between 25 and 150 mg·L−1. Pre-ozonation resulted in a removal of pharmaceuticals at pH 10.0, time of 15 min and coagulant concentration of 52.5 mgL−1. The intermediate ozonation provided a removal with pH 10.0 and a time of 5 min of bubbling. Based on the results, it was confirmed that the synergy of the ozonation process with conventional water treatment is an effective, sensitive and fast method for the removal of pharmaceuticals from the aqueous medium. HIGHLIGHTS The water treatment is insufficient for the removal of drugs.; The adverse effects of drugs in water are still unknown.; The Arroio Dilúvio, a stream, flows into the Guaíba River, which is used as a source of supply for the treatment of water in the city.; Ozonation is effective for drug removal and mineralization.; Ozonation provides a reduction in the amount of reagents used to regulate pH and for coagulation.;

Keywords

• advanced oxidative processes
• experiment planning
• ozonation
• water treatment