The Effect of Varying Salinity and Temperature on the Dynamics of Orimulsion in Water

Abstract

ABSTRACT Studies have shown that Orimulsion behaves somewhat predictably in saltwater (33 ppt NaCl) and freshwater, driven by buoyancy to rise in saltwater and sink in freshwater, but behaviour in brackish water (20 ppt NaCl) is difficult to predict. Temperature has also been indicated as having an influence on Orimulsion behaviour. The current study extended experimentation to lower temperatures and a large number of salinity values, ranging from fresh to saltwater. This study resulted in information on the behaviour of Orimulsion spills in salt, fresh, and brackish water with salinity values ranging from 0.1 to 33 °/oo at temperatures of 5 and 15 °C. Depletion rates and characteristics were determined by adding Orimulsion to a 300-L tank of water, taking a time series of samples, and determining the concentration of bitumen and the particle size distribution. Changes in bitumen concentration and particle size distribution as a function of time were also measured. Resurfaced bitumen was scraped from the top of the tank and weighed to determine the amount rising. Using these data, simple equations were developed to describe and predict the concentration of bitumen in the water column as a function of time. Similarly, nomograms showing the amount of oil on the bottom and on the water surface are presented.