Qualitative variability of roof harvested rainwater and its importance for the conception of treatment system

The aim of the present work was to study the quality and variability of runoff and stored rainwater. Descriptive statistical, correlational, and principal component analyses were performed. The rainwater samples were taken from the buildings of Sao Paulo State University Julio de Mesquita Filho, located in Rio Claro. For the present study, samples from 43 rain events were used, which had been collected from March 2010 to April 2012. The results indicate that the conception of rainwater treatment systems must consider the high variability of rainfall quality. The results from the principal components analysis indicate that solids deposition during dry periods and the organic matter decomposition are the main factors affecting the variability of harvested rainwater, thus requiring operationally flexible technologies.