Efficacy Assessment of Brewery Wastewater Treatment Practice using Physico-chemical Characterization and Toxicity Markers in African Mud Catfish (Clarias gariepinus Burchell, 1822) and African Brackish Water Shrimp (Palaemonetes africanus Balss, 1916)

Industrial activities and urbanization in developing countries have gradually led to the deterioration of the environment in recent years. Large quantities of wastewater effluent are inadequately treated or untreated before discharge into receiving waterbodies, resulting in environmental health concerns. Thus, this study investigated the efficacy of a brewery wastewater treatment system in Lagos by assessing the physicochemical characteristics, acute toxicity, and oxidative stress induction capabilities of the influent (untreated) and effluent (treated) on African mud catfish, Clarias, gariepinus and brackish water Shrimp, Palaemonetes africanus. The test organisms were acutely and sub-lethally exposed to predetermined concentrations of treated and untreated brewery wastewater. Results from the physicochemical assessment of the respective wastewater indicated that the treatment process was relatively effective in improving acidity levels (80.0% reduction), suspended solids (88.0% reduction), total nitrogen concentration (77.0% reduction), chemical oxygen demand (24.05% reduction), and biological oxygen demand (30.0% reduction), while nickel and cobalt concentrations reduced by 50%. Also, there was improvement of dissolved oxygen by about 250%. The 96 h LC50 value of the Catfishes and shrimps exposed to treated wastewater were 12.926 ml/L and 1.095 ml/L respectively compared to and 10.371 mg/L and 0.061 mg/L for the untreated wastewater, indicating an improvement factor of 1.23 and 17.95 for both species, correspondingly. Inhibition of the levels of activities of anti-oxidative enzymes (Reduced glutathione GSH, Superoxide dismutase SOD, and Catalase CAT) and increased lipid peroxidation damage (Malondialdehyde MDA) were recorded in all treatments for both test species, relative to the unexposed control groups. The enzymes however did not show significant trend with respect to the wastewater treatment status. Overall, it can be concluded that the wastewater treatment improved the effluent quality and such a process should be encouraged and enforced to ensure sustainable use of our water bodies.