The effectiveness of leachate remediation in the implementation of unvegetated constructed wetland

The objective of this research was to examine the effectiveness of leachate remediation that is performed through the implementation of a free water surface (FWS) unvegetated constructed wetland system (UCW). The abovementioned remediation was conducted in a glass house with complete randomized design and using a small-scale UCW referred to as UCW reactor. The reactor was designed to replicate a large-scale FWS UCW and was filled with sand and gravel in a 3:5 ratio. The measurements of the leachate quality throughout the remediation experiment were based on hydraulic retention time (HRT) calculation and carried out on the 1st, 5th, 10th, 15th, 21th and 30th days. Subsequently, the resulted homogenous measurements were analyzed using One-way ANOVA while the non-homogenous ones were analyzed using the Brown-Forsythe test. For further analyses on the resulted statistical data, Turkey-HSD or Games Howell test and Euclidean-distance clustering and biplot were applied. The data representing value decreases in the physicochemical leachate parameters suggest the improvement of the leachate quality throughout the treatment. It was proven that FWS UCW is effective in reducing conductivity, total dissolved solids (TDS), nitrate and orthophosphate contents by 51.31%, 32.94%, 52.25% and 36.24%, respectively on the 5th day. On the 30th day, the leachate quality was further improved as the decreases of the four substances reached 79.64%, 56.28%, 80.58% and 90.39%, respectively.