This research project aimed to determine the technologically feasible and applicable wastewater treatment systems which will be constructed to solve environmental problems of small communities in Turkey. Pilot-scale treatment of a small community's wastewater was performed over a period of more than 2 y in order to show applicability of these systems. The present study involves removal of phosphorus in horizontal (HFCW) and vertical (VFCW) sub-surface flow constructed wetlands operated in series. The pilot-scale wetland was constructed downstream of anaerobic reactors at the campus of TUBITAK-MRC. Anaerobically pretreated wastewater was introduced into this hybrid two-stage sub-surface flow wetland system. Wastewater was first introduced into the HFCW and then VFCW before being discharged. VFCW achieved up to 60-90% phosphorus removal whereas HFCW could remove only less than 20%. The effect of type of filling material on adsorption of phosphorus was investigated both in adsorption studies and in 1 m(2) constructed wetlands filled with different materials. The results showed that iron slag was the most efficient material for phosphorus removal in constructed wetlands compared to gravel, marble stone and zeolite.