Constructed wetlands (CWs) have increasingly been developed worldwide for stormwater and wastewater treatment. In this context, CWs have been seen as an economically attractive, energy-efficient way of providing high standards of wastewater treatment. In the present study, a CWS has specifically been designed and operated for domestic wastewater treatment. The removal efficiency of basic pollutants was evaluated in the CWs under free water surface (FWS) and horizontal subsurface flow conditions, employing two native species: Paspalum paniculatum and Thalia geniculata. The experimental results showed that the retention time throughout the treatments varied from 6.5 to 7.5 days; while temperatures of approximately 26°C were observed to reduce the load of pollutants. The experimental tests were highly effective for the wastewater treatment since the removal efficiencies of biological oxygen demand (BOD), chemical oxygen demand (COD), total suspended solids, total nitrogen, and total phosphorus were found to be in the range of 79%–94%. The experimental data were statistically analyzed by the ANOVA approach and Tukey´s test. The treatments showed highly significant statistical differences (P<0.05). From the operating cost standpoint, the current native vegetation was proven to be satisfactory for wastewater treatment in tropical regions of Mexico.
constructed wetlands, removal efficiency, wastewater treatment
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