Comparison of permeable pavements effluent under Atlantic and Mediterranean rainfall regimes: A mid-term laboratory experience

Abstract

Sustainable Urban Drainage Systems (SUDS) can take many forms, but the main idea is to manage and use rainwater close to where it falls, i.e. at source. Permeable Pavements (PPs) are a specific type of SUDS aimed to laminate a rainfall event and reduce runoff pollution. This study describes the influence of dust accumulation, rainfall regime and the pavement configuration in the quantity and quality of infiltrated water in mid-term operation period (one or two years). The total drained volume has not been significantly different between PP configurations, but PPs under the Mediterranean (MED) rainfall regime are able to retain more volume (from 4.48 to 9.85 l/m2) than those under Atlantic (ATL) regime (from 1.32 to 8.82 l/m2). Regarding the quality results, initial values of pH and Electrical Conductivity (EC) in water infiltrated were considerably high and decrease with the number of washings, therefore more quickly under Atlantic rainfall regime (pH values from 11.5 to 7.8 and EC values from 2200 to 110). The water infiltrated from PPs subjected to a Mediterranean rainfall regime contain higher concentrations of all the pollutants studied (the higher values for ATL of COD, TSS, TN and TP were 37.5, 15.1, 2.41 and 0.300 respectively; while for MED were 97.0, 31.8, 4.73 and 0.637). PO43− concentration exceeds the cut-off value in legislation of 0.16 mgP/l since the four months of operation for Mediterranean regime. The results suggest that it is important to pay attention to phosphorus species (specially in Mediterranean regime) in mid-term operation period of PPs.