Bioremediation of waste drilling fluid: comparison of biostimulation and bioaugmentation

In this study, waste drilling fluid was remediated by both biostimulation with the inorganic nutrient addition and bioaugmentation with the inoculation of a selected and well-adapted microbial consortium. The results showed that, compared to the non-bioaugmented system, the bioaugmented system exhibited considerably stronger pollution disposal abilities, with 95.2% total organic carbon degradation (TOC) and 91.2% total petroleum hydrocarbon (TPH) removal within 120 h. In contrast, in the non-bioaugmented system, the corresponding TOC and TPH removal efficiencies were 82.9% and 58.3%, respectively, within 120 h. The active role of the microbial inoculum in pushing the entire community towards an effective bioremediation has been proven through hydrocarbons analysis and metabolic profiling at community level (Biolog system).