Avaliação do desempenho de uma unidade em escala real para tratamento de água pluvial empregando a filtração rápida por meio de filtro de pressão e amido natural de milho como coagulante primário

Abstract

This study aimed to investigate the performance of an experimental rainwater treatment system for non-potable uses without the first-flush discharge, thus intending to control the quality of captured rainwater and to minimize the rainwater by-pass caused by the first-flush strategy. A full-scale direct filtration unit was operated and a solution of natural corn starch was used as the primary coagulant. The color, turbidity e coliform efficiencies of the unit was analyzed based on filtration loads and the net water production was estimated. The results indicated that the system was able to reduce the discharge of the first rain batch, although it was not fully adequate in terms of removal efficiency, suggesting that more studies are needed. The reduction of volume was equivalent to 1.7 mm in absolute terms (or 85%). The apparent color and turbidity removal was around 30 and 54% average, respectively. Additionally, the rainwater production cost for harvesting was R$ 0,99/m3 (or 90%) cheaper than the drinking water public source.