Caractérisation physico-chimique des lixiviats d’une décharge : cas du lieu d’enfouissement sanitaire de Ouèssè-Ouidah (sud Bénin)

By searching for physico-chemical characterization of the pollutants in the leachates of the Sanitary Burying Place of Ouèssè-Ouidah, parameters such as temperature, electric conductivity, pH, dissolved oxygen, redox potential, anions (chloride, nitrate, nitrite, sulfate), cations (sodium, potassium, calcium, magnesium, ammonium), metals (iron, nickel, lead, aluminum, zinc), BOD5, and COD were determined. The obtained results show that the leachates of the site are highly turbid (>1100 NTU), heavily loaded with suspended solids (>470 mg/L), and therefore very polluted (dissolved oxygen about 1 mg/L). Leachates are also characterized by a high iron content (1829.15 ± 2.82 to 2099.49 ± 12.82 μg/L) and a high chloride concentration (192.49 to 227.89 mg/L). The content of the samples in oxidizable matter (COD on the order of 1161.0 to 1278.0 mg O2/L; BOD5 on the order of 95.8 to 107.0 mg O2/L) and nitrogenous compounds (220 to 400 mg/L) remains very high. The analyzed leachate samples also have a high mineral content (conductivity: max = 218 mS/cm).