Removal of selected risk elements from wastewater in a horizontal subsurface flow constructed wetland

Removal of Pb, Cd, Cr, Mo, V, Be and Ba from municipal wastewater using a horizontal subsurface flow constructed wetland was studied. The removal efficiencies attained for these elements were 50, 86, 71, 59, -53, 37 and 40%, respectively. The average inflow and outflow Pb concentrations were 1.5 and 0.7 mu g/L. Similarly, the inflow and outflow concentrations of 0.14 and 0.02 mu g/L were obtained for Cd. Cr inflow and outflow concentrations were 3.7 and 1.1 mu g/L, respectively. Concentrations of 0.78 and 0.32 mu g/L were measured for Mo. V was washed out from the system. Its average inflow and outflow concentrations were 4.8 and 7.4 mu g/L, respectively. Be inflow and outflow concentrations were rather low (1.03 and 0.65 mu g/L), however, the concentrations of Ba were significantly higher (189 and 113 mu g/L). The main perspective of the constructed wetland is the removal of toxic elements forming insoluble compounds (e.g. CdS) depositing in the wetland bed.