Subsurface-horizontal flow constructed wetland for sewage treatment under Moroccan climate conditions Original Research Article

Performance and behaviour of a subsurface-horizontal flow constructed wetlands (SSF-h CW) used for sewage post-treatment behind an upflow anaerobic reactor under Moroccan climate conditions are reported. The experimental setup included three parallel beds of 28m2, each receiving 9.5m3d−1 of pre-treated sewage corresponding to a hydraulic loading rate of 0.34m(m2 d)−1 and a COD loading rate of 0.15kg (m2 d)−1. Beds 1 and 2 were planted with Phragmites australis and Arundo donax, respectively, and bed 3 was kept unplanted (control). Average data reported here coincided with a plant age going from 12 to 18 months and covered an entire cold season and the early part of the hot season. Average water losses by evapotranspiration amounted 40 and 57mm d−1, respectively, for Arundo and Phragmites, while evaporation did not exceed 7mm −1 for the unplanted bed. Percentage of losses given as the ratio of lost flow/applied flow, amounted 11, 17 and 2%, respectively, for Arundo, Phragmites and the control.