A series of sand filters in the shape of a “U” are an inexpensive option to to the treatment of nitrogen pollution. This filter system was contained three compartments. Each compartment was contained two columns, a filter column and a settling one. The size of filter media decreased successively in the direction of water flow. This disposition of layering increases solids absorption et adsorption. However, the filter sand depth and media grain size can impact their treatment efficiency. Thus, the effect of sand filter depth and media grain size upon treatment kinetic was studied. To do this, three (3) sand depth (60, 70 et 90 cm) was studied. The results show that the filter bed depth of 90 cm was the most efficient for nitrogen removal. However, the coarse shales provide a good reduction of ammonium and Total Kjeldahl nitrogen in the filtrates compared to the other media grain size. Shale medium and lagoon sand are efficient in the nitrate removal and chemical oxygen demand. The results obtained show that the filter of 90 cm of mean shale and with lagoon sand is an efficient technology for treating nitrogen urban wastewater.

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.