Bioremediation of Crude Oil-Contaminated Water and Sediments from the Shatt Al-Arab River (SAR)

Abstract

In the SAR, the oil-degrading bacteria (O-DB) are widespread, forming 8 % to 14 % of heterotrophic bacteria
(HB). The O-DB numbers and biodegradability of petroleum hydrocarbons (PHY) are important in summer
(SU) and sediments (SE) compared to winter (WI) and water (WA). The common O-DB retrieved from the
SAR are Pseudomonas sp. (PS), Pseudomonas putida (PP), Pseudomonas fluorescens (PF), Pseudomonas
aeruginosa (PA), Pseudomonas cepacia (PC), Corynebactrium sp. (CO), Bacillus sp. (BA), Bacillus cereus
(BC), Bacillus subtilis (BS), Flavobacterium sp. (FL), Aeromonas sp. (AE), Arthrobacter sp. (AR), Vibrio
sp. (VI), Nocardia sp. (NO), Acintobacter sp. (AC), Micrococcus sp. (MI), and Staphylococcus sp (ST). The
most effective O-DB utilized more than 52 % of oil in 21-days. A mixed culture made of mutant PP+AR
utilized 93 % of oil during the same period. The oil biodegradation rates in the SAR have been restricted
by biotic and abiotic factors. By providing these factors to the oil-contaminated sites would improve the
degradation rates. The biodegradation of n-alkanes was much faster than polycyclic aromatic compounds
(PAC).