Constructed wetlands serve as an eco-friendly solution for treating landfill leachate, leading to reduced energy use, economic savings, and less environmental harm. A novel study in the cold climate of western Iran has examined the effectiveness of Phragmites australis, also known as common reed, in a pilot-scale project. The study focused on the reed's capacity to bioaccumulate and translocate heavy metals within a horizontal subsurface flow constructed wetland. The findings revealed significant removal rates for heavy metals such as Fe, Mn, Cd, Cr, Ni, and Pb, with efficiencies of 81.23 %, 76.02 %, 26.92 %, 44.73 %, 20.13 %, and 28.24 % respectively. The bioaccumulation factor for these metals was above 1.0, signifying effective uptake by the plant. However, the translocation factor for all metals, except for Mn, did not exceed 1.0. This indicates that although Phragmites australis is an effective phytostabilizer, effectively sequestering heavy metals in its root system, it is not adept at moving these metals to its aboveground tissues. Rather, it tends to concentrate them within its roots and rhizomes.