ABSTRACT
This research is aimed to evaluate the effectiveness of cassava mill effluent (CME) as a bioremediation agent for restoring hydrocarbon-polluted soil. The study encompassed several objectives, including assessing contamination levels, analyzing treated soil chemistry, evaluating soil quality changes, and providing practical recommendations. The key research questions explored the efficacy and efficiency of CME in degrading used engine oil contaminant, optimal remediation conditions and frequency. The research methodology involved collecting soil samples, introducing pollution with used engine oil, and treating them with CME at different frequency. Soil physicochemical analysis were conducted to measure total organic carbon (TOC), total and available phosphorus, total and available nitrogen, soil texture and total petroleum hydrocarbon (TPH) content. The findings revealed notable differences in physicochemical properties between daily treated polluted and non-polluted soils (NTD and PTD) and other treatment regimes. After 30 days of treatment, daily-treated polluted and non-polluted soils exhibited high increase in TOC (1.483%, 1.068%), total phosphorus (441.62mg/g, 14.56mg/g), available phosphorus (10.93mg/g, 24.53mg/g), total nitrogen (0.664mg/g, 0.042mg/g), and available nitrogen (0.079mg/g, 0.104mg/g) compared to initial (baseline) values. This suggests that daily treatment with CME effectively enhanced soil fertility and reduced hydrocarbon contamination. This research demonstrates that cassava mill effluent is a promising bioremediation agent for hydrocarbon-polluted soil. Daily treatment with CME can significantly improve soil physicochemical properties, making it a feasible and environmentally friendly option for soil restoration. However, further studies are needed to address long-term effects, environmental considerations, and scalability in real-world scenarios. These findings offer valuable insights for the practical application of CME in soil bioremediation, contributing to sustainable environmental management practice.
