Influence of Different Porous Media and Ornamental Vegetation on Wastewater Pollutant Removal in Vertical Subsurface Flow Wetland Microcosms

To investigate the effects of porous media and ornamental plants on pollutant removal in vertical subsurface flow constructed wetlands (CWs), 24 microcosm systems were tested from March to August 2015. Twelve microcosms contained porous river rock (PRR) and 12 contained tepezil (TZ) as the porous medium; 3U of each porous medium were planted with Typha spp. (P1), three were planted with Zantedeschia aethiopica (P2), three were planted with Alpinia purpurata (P3), and three were unplanted. The hydraulic retention time of all of the units was 3 days. Rural community wastewater was treated in wetland microcosms. Several water quality parameters were evaluated at the inlet and outlet units. Main findings of this study reveal that both porous media were efficient in the pollutant removal. Removal efficiency showed dependence on ornamental plant types. P-PO4, BOD5, and N-NO3 were reduced by more than 40%, 80%, and 40%, respectively, in P1 and P2. Relative growth rates of aerial, root, and total biomass were positively correlated with the P-PO4 removal efficiency. According to these results, this study suggests the use of ornamental plant production for wastewater treatment and for improving aesthetic systems and public acceptance. This study also recommends the use of PRR and TZ as porous media materials in the design of new CWs. The selection will depend on abundance of material in the study area.