Green roof drained rainwater quality assessment: a physicochemical analysis from a case study in Northeastern Brazil

摘要

Abstract Green roofs have attracted a lot of attention from architects and engineers based on the benefits associated with their use. This research was carried out in a Brazilian semiarid region, where water is first needed for drinking and food preparation. This paper investigates the water quality drained from two green roof systems and one roof with tiles; the physical–chemical parameters were investigated. Rainwater and water percolating separately through each portion of the substrate were analysed. The results show that the water that drains from green roofs has undergone major changes in its parameters, compared to water draining from the conventional roof. It was observed that the change in water quality parameters depends on the vegetation used. In comparison with national standards for water reuse, it was concluded that the water from the green roofs was not suitable for non-potable uses, such as landscape irrigation and toilet flushing.