Plant density may have an influence on constructed wetlands (CWs) operation. In this study, the effect of plant density on the efficiency of vertical-flow CWs planted with Panicum maximum treating domestic wastewater was investigated. Two beds were planted with P. maximum at 10 plants/m2 (low density) and two others at 20 plants/m2 (high density). Two unplanted beds were used as control. During six months, domestic (0.05m3) raw wastewater was applied on each bed intermittently. Wastewater samples were taken once a week into the influent and the filtrate of each bed and preserved at 4°C until analysis. The results showed that pollutants were significantly more removed in the planted beds than in the controls. But, the plant densities used were not significantly impact the treatment efficiency. However, the bed planted at low density was clearly distinguished as the one that provided the higher pollutants removal rates (TSS = 91.8%, DCO = 91.6%, P = 69%, PO43- = 74.9%, NTK = 86.5%, NH4+ = 86.5%, Escherichia coli = 87.1%, Clostridium perfringens = 96.7%).

Sanitation and health of populations regarding malaria and diarrhea syndromes were studied in precarious neighborhoods of Abobo (Abidjan, Côte d’Ivoire). Globally, 587 concessions were sampled with 14 232 people. Human excreta are essentially disposed in autonomous sanitation systems (8-88%). The grouping of neighborhoods according to their sanitation gave three entities: (Anonkoua and Abobo PK-18) (Sagbé, Avocatier, M'Ponon and Jean-Tahi) and (Abobo-Baoulé). People have access to the drinking water from SODECI for various usages depending on the use and the season. Drinking water from SODECI is the only one used in the dry season, but it’s partially substituted by rainwater during the rainy season for bath, clothes washing and dishes. However, it is exclusively used for drinking regardless of the season. The classification of precarious neighborhoods based on water use gives five groups: (Anonkoua, Avocatier) (Sagbé, Abobo PK-18), (Jean-Tahi) (M'Ponon) and (Abobo-Baoulé). Population health in these areas is worrying with 47% of patients (35% of malaria syndrome cases and 12% of diarrhea syndrome cases). The young population ([0-8 years [) is the most affected, with 25% of malaria syndrome cases and 34% of diarrhea syndrome cases.

Pesticides used for intensive agricultural production threaten natural resources and human health. The aim of this study is to analyze the use of pesticides in the Marahou

Four biosand filters were used for treatment of Banco river source water to investigate the effects of sand depth (30, 50, 70 and 90 cm) on the removal of suspended solids, nitrogen and oxidized forms of the chemical demand oxygen and their effect on the pH. The results showed that the filter of 90 cm of sand was the most efficient. However, the purification yields between filters 50, 70 and 90 cm of sand showed no significant difference, and the treated water met the drinking water standards of the world health organization. Therefore, sand depth between 50 and 90 cm can be used in biosand filter to treat water.