Biodegradation of total petroleum hydrocarbons in oily sludge: a comparative study of biostimulation, bioaugmentation, and combination of methods

Abstract

AbstractBACKGROUNDOne of the major parts of global environmental pollution is petroleum‐derived products. The purpose of this study was the biodegradation of total petroleum hydrocarbons (TPH) in oily sludge using biostimulation and bioaugmentation methods. The oily sludge was dredged from the bottoms of kerosene and oil gas storage tanks, and it was characterized according to American Society for Testing and Materials D1796 and the CHNS (equipment for determination Carbon, Hydrogen, Nitrogen and Sulfour) elements analysis. The TPH biodegradation potential of the indigenous bacteria in the oily sludge was investigated via biostimulation applying mineral salt medium(N). Besides it was compared with bioaugmentation with two oil degrader bacterium, namely Arthrobacter citreus (strain E) and Rhodococcus jostii (strain D), being separated from the oil‐contaminated soil. The gravimetric and GC (Gas Chromatography) methods were used for TPH removal assays.RESULTSThe results indicated that the biodegradation efficiency was dependent on treatment time and microbial species. Increasing pH and TPH biodegradation % for samples were observed over time. The highest removal degradations of hydrocarbons (75.1%) was reported using the inoculum mixture of strains D & E (pH = 7.02) at the 5th week.CONCLUSIONThis method could be used for bioremediation purposes at petroleum hydrocarbon‐contaminated sites as a biological technique. © 2020 Society of Chemical Industry