Simulation for dynamic release of oil from oil-contaminated marine sediment

Dynamic oil release from oil-contaminated sediment to seawater was investigated in kinetic and factor experiments. Oil-release kinetic was described using a two-compartment first-order equation with rapid- and slow-release steps. The rapid-desorption-fraction rate (k_r) was not affected by the ratio of solid-liquid, but significantly affected by sediment pollution level and salinity. The slow-desorption-fraction rate constant (k_s) was affected by sediment pollution level, the ratio of solid-liquid, and salinity. Desorption efficiencies were 1.09-4.04%, increasing as the sediment pollution level and salinity increased and the ratio of solid-liquid decreased. Oil desorption was critically affected by sediment suspension (or lack of). The desorption kinetics curves were unaffected with the shear force for unsuspended sediment, and the desorption efficiency and k_r were increasing with the shear force for suspended sediment, and no significant correlations were found between k_s and hydrodynamic conditions. The results provide a theoretical basis for evaluating ecological risks posed by oil in sediment.