Algae Culturing from Wastewater Samples and Captured Exhaust Gas for Sustainable Fish Cultivation

Wastewater and exhaust gases from diesel engines are significant environmental pollutants, contributing to nutrient overload and greenhouse emissions. However, these waste products offer a potential solution for nutrient recycling and fish feed production. This study explores the sustainable cultivation of algae using wastewater and captured diesel exhaust gas from diesel generators for fish feed production, addressing environmental and economic challenges in aquaculture. Wastewater from fishponds and food processing industries, along with exhaust gas from diesel generators, were analyzed for their physicochemical and biological properties. Algae species such as Chlorella vulgaris and Cyclotella sp. were successfully cultured in the wastewater enriched with exhaust gas, demonstrating high nutrient content suitable for fish feed. African catfish (Clarias gariepinus) fed the algae-based diet exhibited superior growth (25 cm final length, 0.8 kg weight gain) and lower mortality (12.5%) compared to ca control group fed conventional feed (22 cm, 0.5 kg, 25% mortality). Hematological analysis indicated enhanced immune response in algae-fed fish, though slight liver and kidney stress was observed. The results confirm the feasibility of repurposing wastewater and exhaust gas for algae production, offering a sustainable alternative to conventional fish feed while mitigating environmental pollution. This approach supports resource efficiency and food security, aligning with sustainable goals. Further optimization of the algae culture process could enhance its scalability and minimize metabolic stress in fish.