One way to entrap or to divert oil is by using booms. There are many methods for entrapment and methods for entrainment using booms in various configurations. The entrainment method is used to divert oil that is in fast moving water. Entrapment can be used when the surface oil can be entrapped, the boom brought around in a “teardrop” or other formation, and the surface oil collected by special equipment.
Oil Deflection booms are used in fast moving water that is moving at .75 to 1.0 knots. There are many rivers and waterways where oil is transported and where the tide is fast moving. This is a tricky process, however, as the boom must be at a particular angle to the moving water and oil. There are great hazards in deploying, placing and moving the booms in rapidly moving water, but this method offers a chance to deflect the oil away from or toward areas where it can either be prevented from landing or be picked up.
For oil that is suspended in water, or the non floating oil spill, the oil drops and works with water columns or it can sink to the bottom as oil, or as tarry globules. There is not good information or documentation about non floating oil spill recovery, making the need for more monitoring necessary. Currents keep the oil moving in ways that allow it to sink and mix in with sand and soil or stay with the tides, coming and going with the tides. Mapping, containing and recovery are the actions that are taken to deal with non floating oil. This might require special permits to disturb the bottoms, or benthic zones by emergency dredging, which also displaces large volumes of water.
Other than booming and dredging, there is bio remediation, where natural bacteria is used to accelerate the decomposition of the oil. One method, nutrient enrichment, adds nutrients, particularly nitrogen and phosphorous, to enhance the growth of the particular bacteria. In natural microbe seeding, the actual bacteria are added when they are not in large enough quantities. Some of the products that promise bio remediation might contain surfactants that break up the oil more effectively, however.
A last ditch method is to burn the site. This can cause air pollution for a time, or it can cause problems on land, especially since plants are intially burned. This might lead to short term soil erosion and other problems with animals overgrazing on emergent plants. Also, a crust may form that has to be removed and disposed of. Generally, this method is supposed to be done as part of an overall plan and in conjunction with land management agencies.
There are new technologies and products entering the market on a regular basis. Many are untested and untried, except in limited test situations, so the process of coming up with safe, nontoxic and effective ways to clean up oil spills will be an ongoing one. There might not be acceptance or approvals for all new ideas and products until they prove themselves.
The most important part of oil spill cleanup is in the planning process. Plans for responding quickly and effectively to various types of spills involve many government agencies, some of which might work against the plans of others, if the plans involve putting great risk on local freshwater or oceanic waterways.
NOAA Response and Restoration guidebook
