Full-Scale Constructed Wetlands Planted with Ornamental Species and PET as a Substitute for Filter Media for Municipal Wastewater Treatment: An Experience in a Mexican Rural Community

Abstract

Alternative polymer-based filter media and ornamental plants in constructed wetlands (CWs) are a relatively unexplored field. These approaches have the potential to reduce construction costs and enhance the aesthetic appearance of CWs. This study evaluated for the first time the use of ornamental plants as monoculture and polyculture, as well as the incorporation of polyethylene terephthalate (PET) as a filter medium in a large-scale community HC (divided into 12 cells) for the treatment of municipal wastewater. Duplicate cells were planted with monocultures of Canna hybrids, Spathiphyllum blandum, Anturium spp., and Thypa spp., while two units had mixed cultures of these plants and two control units remained without vegetation. Systems with vegetation achieved average removal efficiencies of 86.95, 81.3, 64.6, 85.2, and 52% for COD, BOD5, TSS, TP, and TN, respectively. Meanwhile, in systems without vegetation, the removal efficiencies for these pollutants were 81.33, 72.86, 43.68, 3.93, and 30.70%, respectively, indicating significant differences between vegetated and non-vegetated systems (p < 0.05). The PET-based filter medium showed effective pollutant removal, with values comparable to or surpassing those reported in existing literature. All ornamental species exhibited good development with new offspring and flower production both in monoculture and in polyculture. The use of such a filter medium and ornamental vegetation could make CWs more attractive to rural communities.