Accelerating the natural removal of oil on shorelines : part 2, tilling or mixing techniques

Oiled shorelines can be treated with a variety of methods such as flushing or washing, removal, in-situ treatment, chemical methods, and biological techniques. Each method has advantages and disadvantages depending on the characteristics of the shore-zone, the type of oiling, and the degree to which the shoreline is impacted. This paper focuses on sediment tilling or aeration techniques, one of the in-situ treatment options, and considers when, where, and why it can be appropriate. Sediment tilling accelerates the natural physical removal of oil from shore sediments. In remote areas, tilling is a viable alternative to the removal and disposal of oiled sediments. Oil buried in beaches can be exposed by tilling to subject it to the physical action from water and waves. Experimental studies as well as tilling operations during spill response activities have shown that this is a feasible method for accelerating natural processes in the removal of stranded oil from a shoreline. Sediment tilling is effective in low-wave-energy environments and on well exposed sand or coarse-sediment beaches. It does not cause damage to the environment. The oil from intertidal beach sediments can be released and recovered using shallow underwater agitation. 30 refs., 3 tabs., 8 figs