Tactic CR-6: Recovery with Skimmers and Pumps
Use skimmers (Figs. 35–37) to recover oil floating on the water surface. A variety of skimmers are available that are designed for different situations. The choice of skimmer to use is dependent on factors such as the thickness of the floating oil layer, the depth of water, the degree of weathering of the oil, and whether the oil has been treated with surfactant. Skimmers are most effective when the floating oil is concentrated in a thick layer. Position the skimmer in the area of heaviest concentration of spill residue. A skimmer requires a power pack; a pump with suction and discharge hoses and fittings; and a storage container for recovered product.
At a spill site adjacent to a road or pad, a vacuum truck can be used to drain an area (Tactic TR-1) or to recover pooled spills (Figs. 38—39), flood water (Tactic CR-7) or flush water (Tactic CR-8) from natural depressions, land barrier containment (Tactic CR-5), or trenches (Tactic CR-9). The effective range of a vacuum truck is approximately 200 feet when removing viscous liquids such as crude oil, and 400 feet when removing diesel or water. A Super Sucker can be used for direct suction to remove liquids combined with solids (e.g., gravel) that vacuum trucks cannot handle (Fig. 40).
Submersible pumps or trash pumps can be used to pump areas that are not accessible by vacuum truck or Super Sucker. Submerge the pump or intake hose in the deepest area of an impoundment. Make sure the pump intake or hose end is fitted with a screen to prevent vegetation from clogging the intake hose.
Considerations and Limitations
- Identify the disposal method or facility to be used and estimate the volume of liquid requiring disposal before skimming or pumping fluids from a spill site.
- Identify the flash points of fluids being recovered.
- Consider ambient temperature when selecting length and diameter of hoses.
- This tactic has been adapted from Tactics R-6 and R-8 in the Alaska Clean Seas Technical Manual (http://www.alaskacleanseas.org/techmanual.htm).
Equipment, Materials, and Personnel
- Any shallow draft skimmer (e.g., rope mop or Manta ray) (usually 2 operators to deploy and maintain) - to remove floating product.
- Manta ray skimmer (1 or 2 operators to deploy and maintain) - to remove floating product.
- Power pack - to provide a power source for skimmer.
- Pumps and hose (2 operators to deploy and maintain) - to suction product from site.
- Tank or tanker truck (1 operator).