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Filtering capability of porous pavements

The objective of this study is to assess the filtering capability of porous pavement models and the quality of rainwater and stormwater filtered by such models. Three slabs of porous asphalt mixtures and two systems composed of porous layers that resulted in porous pavement structures were produced. Data were collected in two phases: using rainwater directly from the sky and then using stormwater collected from a street. The models with different layers were assembled in acrylic boxes and rainwater was stored into the boxes in each rainfall event. Parameters such as pH, dissolved oxygen, ammonia, phosphorus, nitrite, aluminium, chromium, copper, zinc and iron were measured. The infiltration capacity of the models varied from 83.4% to 83.7%. For both rainwater and stormwater quality analyses, there was an increase in the concentration of the following parameters: phosphorus, iron, aluminium, zinc, nitrite, chromium, cooper and pH; there was no significant variation in the concentration of dissolved oxygen; and there was a decrease in ammonia in one of the models. However, the concentrations of only phosphorus and aluminium exceeded the limits established by the Brazilian National Environmental Council and National Water Agency for the use of non-potable water. The models were capable of filtering rainwater and stormwater, and reducing the concentration of ammonia. It can be concluded that it is possible to collect stormwater from asphalt porous surfaces and porous pavements. Porous pavements are able to filter out certain pollutants from stormwater and rainwater, and showed to be an alternative to harvest rainwater for non-potable uses and to recharge the water table.

Keywords: Porous pavement, rainwater, stormwater, pollutants