Removal of micro-pollutants from urban wastewater by constructed wetlands with Phragmites australis and Salix matsudana

This study assessed the ability to remove micro-pollutants from wastewater using herbaceous species (Phragmites australis L.) and trees (Salix matsudana Koidz.) in constructed wetland (CW) systems. The targets of the study were as follows: (i) pharmaceuticals like diclofenac, ketoprofen, and atenolol; (ii) 4-n-NP (4-n-nonylphenol) and the ethoxylated derivatives monoethoxylated nonylphenol (NP1EO) and diethoxylated nonylphenol (NP2EO); (iii) triclosan, a bactericide used in personal care products. The 12 CW systems, filled with clay and gravel, were irrigated with wastewater from municipal area of Pagnana (Tuscany, Italy) and influent and effluent water samples analyzed periodically by gas chromatography-mass spectrometry (GC-MS/MS). The removal efficiency of CWs planted with willow and common red ranged from 8.4 up to 100%, with the higher removal efficiency for triclosan. On the contrary, the removal efficiency of NPs and NPEOs appears lower than pharmaceuticals. Data demonstrated that P. australis efficiently removed NP, diclofenac, and atenolol, while S. matsudana preferentially removed NP1EO, NP2EO, ketoprofene, and triclosan. A specific selection of plants used in CWs could be exploited for the removal of specific xenobiotics from wastewater.