Copper contamination degrades both environmental quality and soil engineering performance, limiting the safe reuse of contaminated land in urban and industrial regions. Sustainable remediation strategies are therefore required to remove toxic metals while restoring soil functionality. This study evaluates the effectiveness of microbial bioremediation using Acidithiobacillus ferrooxidans for the treatment of copper-contaminated soils and the recovery of key geotechnical properties under controlled laboratory conditions. Soil samples collected from the Hyderabad metropolitan region, India, were artificially contaminated with copper sulphate pentahydrate (CuSO₄·5H₂O) at 100, 200, and 250 g/kg of dry soil to simulate severe industrial contamination scenarios. Following 30 days of treatment, copper removal was quantified by ICP–OES, and changes in shear strength, pH, and electrical conductivity were evaluated. Copper contamination reduced the angle of internal friction from 32.84° to 18.99–23.28°, decreased pH from 7.45 to 5.05–6.85, and lowered electrical conductivity from 476 to 290–375 μS/cm. Microbial treatment removed 77.5–85.95% of copper and restored the angle of internal friction to 28.87–31.65°, corresponding to 90–96% recovery of virgin soil values. Soil pH increased to 6.90–7.32 and electrical conductivity recovered to 415–468 μS/cm. The net biological contribution to copper removal, after accounting for physical leaching in control samples, ranged from 13.75% to 27.7%. A strong positive correlation (r = 0.91) between copper removal efficiency and friction angle recovery confirms that geotechnical restoration is closely linked to microbial detoxification. A GIS-based weighted overlay analysis using the Analytic Hierarchy Process (AHP) was used to demonstrate how laboratory-derived results can support contaminated land reuse planning. The findings show that microbial bioremediation can simultaneously reduce copper toxicity and restore engineering functionality, supporting the sustainable reuse of remediated soils.
Krishna et al. (Mon,) studied this question.