| Popis: |
This research work was based on recommendations of a number of researchers stating that pollution has appeared in the Chadian capital, N'Djamena, as a result of the liquid waste being thrown out from some private and public sectors before being treated. This study is a follow-up to research, some of which have been published and some not yet completed. The current article was focused on the determination of some physicochemical characteristics of wastewater in the capital of Chad N’Djamena and to assess their environmental impact. These characteristics were: Temperature, pH, electrical conductivity, TDS, Cu, Zn, Al, Fe, Mn, NO3-, PO43-, HCO3-, chemical oxygen demand (COD), biological oxygen demand (BOD) and total dissolved solids. Samples were taken from four different effluent streams and analyzed according to the standard methods. The results of the evaluation were: pH (4.26 ± 0.06 - 8.57 ± 0.06), temperature (23.17 ± 0.21 - 33.60 ± 0.10°C), electrical conductivity [EC] (212 ± 0.01 - 1997 ± 10 µs/cm), the total dissolved solids TDS (1.42 ± 0.01 - 906.63 ± 1.21 mg/l), chemical oxygen demand COD (30 - 1170 mg/L), biological oxygen demand BOD (26 - 228 mg/L), Cu (0.11 - 6.20 mg/L), Zn (0.02 - 3.53 mg/L), Mn (0.003 - 6.77 mg/L), Al (0.10 -1.12 mg/L), Fe (0.39 - 3.43 mg/L), bicarbonate (23.67 - 853.33 mg/L), phosphate (0.023 - 333.67 mg/L) and nitrate (0.98 - 127.0 mg/L). These results revealed that the values of some parameters are exceeded the limit recommended by the World Health Organization for wastewater discharge. We conclude that this untreated wastewater are sources of pollution to the daily consumed legumes and vegetables. |
