Effect of monocultures and polycultures of and on the treatment of river waters contaminated with landfill leachate/domestic wastewater in partially saturated vertical constructed wetlands.

Partially Saturated Vertical Constructed Wetlands (PSV-CWs) are novel wastewater treatment systems that work through aerobic and anaerobic conditions that favor the removal of pollutants found in high concentrations, such as rivers contaminated with domestic wastewater and landfill leachate. The objective of the study was to evaluate the efficiency of PSV-CWs using monocultures and polycultures of and to treat river waters contaminated with leachates from open dumps and domestic wastewater. Six experimental units of PSV-CWs were used; two were planted with monoculture, two with monoculture and two with polycultures of both plants. The results indicated better organic matter and nitrogen removal efficiencies ( < 0.05) in systems with polycultures (TSS:95%, BOD:83%, COD:89%, TN:82% and NH:99%). In general, the whole system showed high average removal efficiencies (TSS:93%, BOD:79%, COD:85%, TN:79%, NH:98% and TP:85%). Regarding vegetation, both species developed better in units with monocultures, being the one that reached a more remarkable development. However, both species showed high resistance to the contaminated environment. These results showed higher removals than those reported in the literature with conventional Free Flow Vertical Constructed Wetlands (FFV-CWs), so PSV-CWs could be a suitable option to treat this type of effluent.