Approach to Treating Contaminated Water in Flood Scenarios in Brazil: Case Study of Arroio Dilúvio

Abstract

Floods, such as those affecting the Arroio Dilúvio, can contaminate waters with various pollutants, exposing the population to health risks. Emergency treatment of these waters is crucial, and ozonation emerges as a promising solution due to its oxidizing capacity. This study aims to establish optimal parameters for a compact treatment unit, integrating ozonation into conventional water treatment (pre-ozonation and intermediate ozonation stages) to address these challenges in Brazil. Water samples were collected from the Arroio Dilúvio in Porto Alegre, RS. A factorial design using central composite design (CCD) was conducted to determine the influence of variables such as pH, time, and gas dosage on the mineralization of the matrix, considering two gas flow rates (0.5 and 1.0 L/min). It was observed that integrating ozonation resulted in an average 25% reduction in coagulant concentration through pre-ozonation, highlighting the benefits of this approach for treating contaminated matrices. Furthermore, it led to increased mineralization at both flow rates (0.5 and 1.0 L/min), achieving final values of 33.2% and 39.0%, respectively (pH 8, 30 min, and coagulant concentration 60 mg/L). Regarding intermediate ozonation, mineralization reached values of 59.0% (pH 8, 30 min; 0.5 L/min) and 83.0% (pH 10, 15 min; 1.0 L/min). The latter not only highlights the effectiveness of the integrated process but also its potential to optimize the operation of more sustainable treatment. The ozone's ability to promote mineralization demonstrates its potential for treating waters in affected areas, offering not only a robust and efficient solution for complex environmental challenges but also substantial benefits in water quality management in Brazil.