OHMSETT TESTS OF TRUCK-MOUNTED VACUUM SYSTEMS FOR OIL SPILL RECOVERY1

Abstract

ABSTRACT Two recent test programs at the U.S. Environmental Protection Agency's Oil and Hazardous Materials Simulated Environmental Test Tank (OHMSETT) examined two different vacuum systems. The first program, performed in September 1980, tested a vacuum truck fabricated by Coleman Environmental and Pollution Control Equipment Co., Inc. and a Vactor 2045 air conveyor system made by the Peabody Myers Company. The vacuum truck produced an average oil recovery rate of 2.4 cubic meters per hour (10.6 gallons per minute) and an oil recovery efficiency of 18 percent. Results confirmed the prevalent belief that this type of equipment is well suited for use in thick slicks (i.e., above 60 millimeters). The addition of skimmer attachments to the hose end increased recovery efficiency without affecting oil recovery rate. The air conveyor tests resulted in an average oil recovery rate of 4.4 m3/hour (19.4 gpm) and a recovery efficiency of 61 percent. The air conveyor worked well, particularly with thinner slicks. The independent variables incorporated into the first test program included slick thickness, test oil viscosity, blower speed, length of the recovery hose, the height of the suction hose end above the slick, and use of skimmer attachments. The second test program, performed in August 1982, extended the investigations of the initial program, adding a more viscous test oil, debris, and a different skimming attachment for the hose end. Also included were tests to confirm results of the first program. The truck used in the second program was another vacuum truck made by Coleman Environmental and Pollution Control Equipment Co., Inc. The standard vacuum truck yielded an average oil recovery rate of 5.0 m3/hour (22 gpm) with an average oil recovery efficiency of 51 percent. This was over nine different phases, each phase studying the effect of a different combination of variables. Skimming a higher viscosity test oil in the range of 11.2 centipoise (cp) to 318 cp caused an increase in oil recovery rate and recovery efficiency. The addition of a skimming attachment increased recovery efficiency and decreased oil recovery rate. Tests with debris confirmed the necessity of keeping debris away from the hose end.