Abstract
Some industrial wastewaters contain high levels of non-biodegradable organic and inorganic matter, and in-house physical and chemical treatment produces secondary pollutants that are released into the receiving environment and can harm the ecosystem. Over the years, conventional biological treatment of these industrial effluents has proven ineffective. Advanced biological aerobic and anaerobic methods, in which biomass is nurtured for growth and biochemical manipulations are used to present a variety of value-added products with potential applications, have been adopted. As CO2 gas is sparged through the broth, the microalga Scenedesmus sp. accumulates lipid as it mops up minerals and nutrients from brewery wastewater to produce biomass. Standard methods were used to determine the mineral content of brewery wastewater from Durban, KwaZulu-Natal. Scenedesmus sp. was then grown in wastewater using bubble-column photobioreactors, with the broth being CO2-sparged at regular intervals. The optical density reading on the DR 3900 spectrophotometer was used to track biomass production, and lipid accumulation was measured using the chloroform-methanol solvent system. The findings revealed that the minerals in the effluent brewery wastewater contained high levels of cadmium, exceeding the WHO limit of 0.03 mg/L. Zinc (1.578 mg/L) and nickel (0.053 mg/L) concentrations were both within WHO limits of 5.0 mg/L and 1.0 mg/L, respectively. All of the minerals in the effluent were significantly reduced after treatment with Scenedesmus sp. As a result, during the exponential growth period, biomass production increased in tandem with proportional lipid accumulation.
