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Statistical Optimization and Kinetic Studies of Enhanced Bioremediation of Crude Oil - Contaminated Marine Water Using Combined Adsorption-Biostimulation Strategy
AGARRY, SAMUEL E.
Abstract
The objectives of this study were to investigate and evaluate through Taguchi
orthogonal experimental design the effects of amendment agents as well as the optimization and
kinetics of enhanced bioremediation of crude oil-contaminated marine water using combined
adsorption-biostimulation strategy. The amendment agents are organic fertilizer, slow release
inorganic NPK fertilizer, commercial activated carbon and Tween 80. Bioremediation of
weathered Escravos crude oil (WECO)-contaminated marine water was studied for four weeks
in ten plastic buckets open system. The oil-contaminated marine water in nine of the buckets
was each amended with the amendment agents according to Taguchi’s (L9) orthogonal array of
four factors and three levels and the tenth un-amended bucket served as control (natural
bioattenuation). Results showed that the amendment agents had relative significant influence on
the enhancement of WECO-marine water bioremediation. The optimum amendment agent
conditions were determined as follows: organic fertilizer 30 g, inorganic slow release NPK
fertilizer 4 g, activated carbon 30 g, and Tween 80, 1.5 g. Under these optimum conditions, the
optimum percentage of crude oil biodegradation achieved was 98.25%. Bioremediation kinetic
data of WECO fitted well to the first-order kinetic model. The combined adsorptionbiostimulation
strategy (using the amendment agents) resulted in higher biodegradation rate
constant, k (0.0443 - 0.1183 day-1) and lower biodegradation half-life, t1/2 (5.86 – 15.6 days)
of the WECO biodegradation than the natural bioattenuation with lower k (0.0144 day-1) and
higher t1/2 (48.8 days). Therefore, the amendment agents have effective potential application
as a tool for combined adsorption-biostimulation strategy in the remediation of crude oilcontaminated
aquatic environment.
Keywords
Biodegradation; Bioremediation; Amendment agents; Crude oil; Kinetics; Optimization
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