EFFECTS OF TEMPERATURE ON BIOAVAILABILITY OF CRUDE OIL COMPONENTS

摘要

Effects of temperature on the bioavailability of Tapis crude oil components during a biodegradation process by an indigenous soil microorganism, Acinetobactor calcoaceticus were studied. The highest total petroleum hydrocarbon (TPH) oil removal were achieved at 30°C for both TPH (72.28%) and aliphatic hydrocarbons (64.03%) at the end of a 60-day period. At 20°C, the oil removal were lower, 65.26% for TPH and 60.26% for aliphatic (C9-C30). The highest rate of total oil removal per stone surface area occurred at 30°C during the first day of the incubation period (31.63 mg/cm2/day), while the rate of removal at 20°C was only 22.06 mg/cm2/day. At the end of the experiment, the degradation rate decreased to 0.79 and 0.72 mg/cm2/day for 30° and 20°C, respectively. The results obtained indicated that high temperature significantly enhanced the rate and extent of the oil biodegradation. Furthermore, abiotic hydrocarbon removal also elevated the oil degradation. The GC chromatograms showed that the aliphatic components, especially C10 to C20, disappeared more rapidly at 30°C than at 20°C. This suggested that the physical processes, such as aeration, volatilization, the movement of a liquid medium, and oil solubilization, could contribute to the abiotic losses of oil.