Bioremediation of Copper-Contaminated Soil by Co-Application of Bioaugmentation and Biostimulation with Organic Nutrient

Abstract

ABSTRACT This study investigates various factors affecting bioremoval of copper from experimentally contaminated soil by bioaugmentation with a metal-resistant microorganism (B1) accompanied with amendment of an organic matter (mustard oil cake). The initial contamination level reduced by 67% with this joint strategy compared to 13% by application of bioaugmentation. Increasing organic amendment concentration beyond 6 wt% did not significantly improve microbial growth and the extent of bioremediation due to increase of pH. The bioaccessible copper concentration, however, did not change significantly. Controlling pH by one-time application of ferrous sulfate (1 wt%) into the experimental run resulted in enhanced microbial growth. The copper concentration in soil and bioaccessible copper concentration reduced to 55% and 80% of the value obtained without pH control for the same period of incubation. This study suggests the potential of co-application of isolated metal-resistant bacteria (B1) and mustard oil cake amendment in conjunction with pH control for in situ bioremediation of copper-contaminated soil.