Aggregation between suspended sediment grains and oil droplets, which leads to the formation of agglomerates commonly referred to as Oil-Mineral Aggregates (OMA), is widely acknowledged as a natural process that enhances dispersion of spilled oil in aquatic environments. A comprehensive numerical approach is developed to predict the contribution of OMA formation to the dispersal of spilled oil. The model comprises four modules to calculate maximum size of oil droplets, to predict formation of oil droplets from a slick, to predict formation of sediment floc, and to calculate density of oil-sediment flocs. The inputs of the model are environmental conditions, oil properties and concentration and grain-size distribution of suspended sediments. Sensitivity analysis performed using five crude oils covering a range of viscosities from 8 10−3 to 68 10−3 kg/ms, a kinetic energy dissipation rate from 10−3 to 102 m2/s3, a sediment grain size of 3 μm and a sediment concentration of 250 mg/l showed that formation of OMA is strongly dependent on the oil-water interfacial tension and the kinetic energy dissipation rate. Under breaking wave conditions, the contribution of OMA formation to the dispersal of spilled oil varies between 31 and 97 % depending on characteristics of the individual test oils, in particular oil-water interfacial tension. Results show also that OMA formation is enhanced when the Weber number approaches a value of 0.05.

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