The effects of seasonality on the quality of rainfall water in the city of rio de Janeiro

Abstract

Critical periods and abnormal rainfall events have been observed in the South-East of Brazil, and this has affected both the amount and quality of the volume of water in the water supply systems. This study seeks to assess the influence of seasonal factors on the quality of rainfall at a water treatment plant, located in the city of Rio de Janeiro - RJ. The methodology involved collecting rainfall samples between January 2017 and December 2018, at four specific points in the system: first flush 1 (FF1), first flush 2 (FF2), void volume (VV) and reservoir (RR). The parameters were analyzed statistically and followed seasonal patterns for each of the seasons of the year, and included: pH, turbidity, electric conductivity, total of alkalinity and chloride. The results suggest that there is an urgent need to dispose of the initial volume stored in the devices of the first flush. The water contained in the tank was of a satisfactory standard for non-drinkable purposes despite the effects of seasonality on the quality of the rainfall water. A multivariate statistical correlation analysis made it possible to assess the influence of the seasons of the year on the quality of pluvial water.