2.1. Small-scale constructed wetlands
Nine beds with 32 cm of sand and gravel; from top to bottom
10 cm of sand, 9 cm of coarse sand, 7 cm of gravel and 6 cm of
stones (Fig. 1) with vertical flow, were constructed indoors, with
a volume of 25 L and a surface area of approximately 700 cm2 in
each bed (Fig. 2). Three beds were planted with common reed (P.
australis) according to Ekman et al. (1991) and three beds were left
unplanted in order to investigate the impact of the root system. In
a parallel control system, three planted beds received the same
volume of water with only nutrients (5 mM Ca(NO3)2; 5mM
KNO3; 2 mM MgSO4; 1 mM KH2PO4 and 1 mM FeNaEDTA and