THE LABORATORY DETERMINATION OF DISPERSANT EFFECTIVENESS: METHOD DEVELOPMENT AND RESULTS

ABSTRACT A research project is described in which a previously devised effectiveness test for chemical oil spill dispersants was further developed and standardized. The principle of the test is that known volumes of dispersant and crude oil are contacted on the surface of seawater in a laboratory-scale vessel in which there is a circulating air current that imparts a swirling wave action to the water. This flow geometry is believed to simulate ocean surface conditions better than tests that involve shaking, stirring, or pumping as turbulence-generating mechanisms. From the results of a series of tests at various dispersant-to-oil ratios, the ratios that affect the dispersion of 50 and 75 percent of the original amount of oil added to the water surface are calculated and used as an indication of dispersant effectiveness. The corresponding percent of the oil that remains dispersed after settling is also deduced. The results of a series of tests using two crude oils, Murban (light) and La Rosa (heavy), and 1...