Bioaugmentation-assisted bioremediation and kinetics modelling of heavy metal-polluted landfill soil

The research is aimed to conduct onsite bioremediation of heavy metal-impacted landfill soil using fungal consortium. The setup involved treatment (soil augmented with fungal consortium) and control (soil without fungal augmentation). The experiment was conducted for 100 days and monitored on Day 20, Day 60, and Day 100. The targeted metals removed from the soil were As, Cr, Cu, Fe, Mn, Ni, Pb, and Zn. The highest metal removal was in bioaugmented soil, with 67% Mn, 67% Ni and 66% Zn removed. The enzyme activities were highest in the treated soil, and the maximum for urease, dehydrogenase, invertase, and acid phosphatase was 2.9 mg NH 4 -N g −1 dry soil 3 h −1 , 1.97 mg TPF g −1 dry soil 24 h −1 , 2.5 mg glucose g −1 dry soil h −1 , and 2.5 µmol PNP g −1 dry soil h −1 , respectively. The results of Fourier transform infrared revealed the presence of thiols, thioethers, disulphides (780–686 cm −1 ), amines (3441–3374 cm −1 ), phosphates (913 cm −1 ), methyl (1422 cm −1 ), and hydroxyl groups (3526—3695 cm −1 ) which supported the proposed mechanisms of the metal removal. The maximum rates of metal removal in the treated soil were As (0.0105/day), Mn (0.0111/day), Ni (0.0110/day), and Zn (0.0108/day). All coefficients of determination were high with the maximum as 0.9996 and 0.9994 for Fe and As, respectively. Bioaugmentation using blended fungi was efficient in enhancing the metal removal from the soil. It is presumed that bioaugmentation can serve as an effective approach for enhancing the clean-up of metal-contaminated soil.