Oil residues along shorelines are hard to remove after an oil spill. The effect of biodiesel to eliminate
crude oil from pebbles alone and in combination with petroleum degrading bacteria was investigated
in simulated systems. Adding biodiesel made oil detach from pebbles and formed oil–biodiesel mixtures,
most of which remained on top of seawater. The total petroleum hydrocarbon (TPH) removal efficiency
increased with biodiesel quantities but the magnitude of augment decreased gradually. When used with
petroleum degrading bacteria, the addition of biodiesel (BD), nutrients (NUT) and BD + NUT increased the
dehydrogenase activity and decreased the biodegradation half lives. When BD and NUT were replenished
at the same time, the TPH removal efficiency was 7.4% higher compared to the total improvement of efficiency
when BD and NUT was added separately, indicating an additive effect of biodiesel and nutrients on
oil biodegradation.