Balanço hídrico e caracterização da qualidade da água pluvial proveniente de um telhado verde em Recife/PE

Abstract

Green roofs have been gaining prominence worldwide due to a series of benefits linked to their use, among them the management of rainwater has been the subject of many studies. Therefore, the objective of this research was to evaluate the quantity and quality of water drained from a green roof for non-drinking purposes. The research was carried out at Edifício Garagem do Empresarial Charles Darwin, Recife / PE (latitude -8.05º, longitude -34.95º). An automatic meteorological station was installed on the building's slab, for recording meteorological data, during the experimental period. The water balance was calculated by quantifying the water inlets and outlets on the roof. Three treatments were evaluated, rainwater, irrigation water and water drained by the green roof and the average values of the water quality parameters were compared with the reference values of the NBR 15527/2007 standard and by the Brazilian ordinance (MS) 2914/2011. The results obtained showed that the average annual retention promoted by the green roof substrate varied from 7 to 9% and that the association of a reservoir increased this variation for retentions above 80% of the total annual incident, a fact that shows the potential of green roofs in mitigating urban flooding. The evaluated treatments (rainwater, irrigation and drainage), did not meet the standards established by the Brazilian ordinance (MS) 2914/2011 and partially met the NBR 15527/2007. However, this water has great potential for use for non-potable uses in addition to being an important alternative for reducing the consumption of water from public supply.