Abstract

Lacina Coulibaly1*, Issiaka Savané2 and Germain Gourène1

A pilot scale constructed wetland planted with Corchorus oliterius was developed for domestic wastewater treatment. The reactor system was composed of rectangular beds realized in cement. Each bed was filled from the bottom to the top with 0.1 m of gravel (15/25 mm) and 0.30 m of a uniformly distributed medium grain (mean sand diameter = 426,66; uniformity coefficient = 0,37) white sand from the Ebrié lagoon. Two beds planted with yang C. oliterius plants (high density: 40 plants/m²; low density: 10 plants/m²) and one control (unplanted bed) were used to perform the experiment. The beds filtrates pH was neutralized to 7. The planted beds removed the COD (low density = 61%, high density = 65%) more than the control (54%). Nutrients were also best removed in the planted beds (NH4 + : 67%, PO4 3- : 52%) than in the control (NH4 + : 11%; PO4 3- : 56%). The increase of the plant density did not influence significantly (p < 0.05) pollutants removal. However, this augmentation increased the bed performance. The plants leaves were less contaminated at 0.9 m above the bed surface, suggesting this height for their harvesting for sale.