Sustainable Method of Waste Water Treatment Using Microalgae: A Case Study of Kano Metropolis

The present study investigates the sustainable treatment of wastewater using microalgae in Kano Metropolis, Nigeria, using changes in the physicochemical condition of the water and algal species distribution across three sampling sites: Sallari (A), Hauren shanu (B), and BUK old site pond (C). Water analysis and algal species identification, culture and isolation for bioremediation potential were carried out for 14 days using standard procedures. The results revealed the mean physicochemical condition of the water temperature of 24.6 ± 0.65°C., Bioremediation potential revealed the dominant algal species of Scenedesmus quadricauda and Chlorella vulgaris)on key water quality parameters including Dissolved Oxygen (DO), Biochemical Oxygen Demand (BOD), pH, Electrical Conductivity (EC), Nitrate-Nitrogen, Phosphate-Phosphorus, Alkalinity, and Total Hardness. Results demonstrated significant reductions in DO (from 3.45±0.13 to 2.45±0.10 mg/L), EC (from 897.33±0.90 to 714±4.10 μS/cm), Phosphate-Phosphorus (from 9.56±1.01 to 5.34±0.18 mg/L), and Total Hardness (from 320.00±2.64 to 210.33±3.78 mg/L), alongside increases in pH (from 8.2±0.7 to 9.93±0.31) and Nitrate-Nitrogen (from 26.8±1.13 to 35.8±0.19 mg/L). Pearson correlation analysis revealed strong positive relationships between total hardness, pH, and algal composition (P<0.01), while negative correlations were observed between total hardness and BOD, TDS, and alkalinity (p<0.05). The findings confirm that microalgae-mediated treatment offers a viable and environmentally sustainable approach for wastewater remediation, with S. quadricauda and C. vulgaris demonstrating significant (p<0.05) efficiency in nutrient removal and physicochemical modulation under tropical conditions. Microalgal species were effective as it removes 78-99% of Nitrogen and Phosphorus. The treatment system also succeeds to remove 40-65% of COD and BOD.