Evaluation of the Impact of Brewery Effluents on the Water Quality of the Congo River

The overall characterization of the raw effluent and the receiving water at the discharge point, Congo River, gave the following results: pH 12.62 ? 0.22 and 11.49 ? 0.61; COD (mgO2 / L) 1287 ? 51 and 1180 ? 41, BOD5 (mgO2 / L) 677 ? 41 and 531 ? 67; PO43- (mg / L) 14.11 ? 1.70 and 13.13 ? 1.91; NH4+ (mg / L) 27.18 ? 2.20 and 23.48 ? 5.02; Electrical conductivity (at 20 ? C, ?S): 16166.2 ? 7569.5 and 10292.5 ? 3973.2; O2 dissolved (mg / L): 0.88 ? 0.20 and 1.06 ? 0.22; T(? C): 29.4 ? 1.3 ? C and 28.5 ? 1.2 ?C. Toxicity testing with Gambusia affinis fish revealed 4.8 mL LL50 and 13.5 mL for crude effluents and receiving waters at the point of release. These results show that crude effluents and receiving waters are toxic to the aquatic ecosystem. They must be monitored, adequately processed and regulated in order to preserve aquatic ecosystems at the point of discharge.