Effect of Co-culture and Nutrients Supplementation on Bioremediation of Crude Petroleum Sludge

Ex-situ bioremediation of real-field crude petroleum sludge was evaluated to elucidate the role of co-culture (bioaugmentation) and external nutrients supplementation (biostimulation) under anaerobic microenvironment. Maximum removal of total petroleum hydrocarbons (TPH) was observed by integrating biostimulation with bioaugmentation (R5, 44.01%) followed by bioaugmentation alone (R4, 34.47%), co-substrate supplemented operations [R6, 23.36%; R3, 16.5%; R2, 9.88%] and control (R1, 4.36%). Aromatics fraction showed higher degradation in all the conditions studied. Fate of six selected polycyclic aromatic hydrocarbons (PAHs) was evaluated during bioremediation. Among these, four ring PAHs compounds showed good degradation by integration of biostimulation with bioaugmentation (R5) while bioaugmentation alone (R4) documented good degradation of three ring PAHs. Lower ring PAHs compounds showed good degradation with the application of biostimulation (R6). Fluorescent in situ hybridization (FISH) detected the presence of known PAHs degrading microorganisms viz., Bacillus, Pseudomonas, Acido bacteria, Sulphur reducing bacteria Firmicutes, etc. Application of biostimulation and bioaugmentation strategies alone or in combinations documented noticeable influence on the degradation of petroleum sludge.