Organic micropollutant removal in a full-scale surface flow constructed wetland fed with secondary effluent.

The mass emission rate of 12 pollutants from a wastewater treatment plant (WWTP) secondary effluent into a small tributary of the River Besòs (northeastern Spain) was determined. The pollutants tested included pharmaceutical and personal care products (PPCPs) and herbicides. Furthermore, a 1-ha surface flow constructed wetland (SFCW) was evaluated for pollution removal. Whereas the low concentration values (ngL(-1)) of PPCP discharge into the tributary was comparable to inter- and intra-campaigns, herbicides and a veterinary drug (flunixin) exhibited a high variability in concentrations (microgL(-1)). Moreover, removal efficiencies were often higher than 90% for all compounds, with the exception of carbamazepine and clofibric acid (ca. 30-47%). As expected, a seasonal trend of pollutant removal in the wetland was observed for compounds with low biodegradation and moderate photodegradation rates (i.e. naproxen and diclofenac).