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OSRR-477-Correlating Results of Dispersants Effectiveness at Ohmsett with Identical At-Sea trial: Effects of Oil Viscosity and Dispersant to Oil Ratios

Office/Division Program
Project Number
Research Initiation Date (Award Date)
Research Performing Activity
S.L. Ross Environmental Research, Ltd.
Research Principal Investigator
Dr. Ken Trudel
Research Contracting Agency

The objectives of this research project are twofold. The first is to determine if the results of dispersant effectiveness tests conducted at Ohmsett are consistent with those gathered in the laboratory and under actual at-sea conditions. The project will conduct a series of dispersant effectiveness tests at Ohmsett under identical conditions to those conducted in the at-sea trials done in the UK in 2003. The research will compare the threshold limiting conditions for dispersibility as measured at Ohmsett with those measured in the laboratory and at-sea, under identical conditions.

Second objective is deployment of the SMART (Surveillance and Monitoring for Alternative Response Technology) monitoring protocols in experiments where direct, independent, measurements of effectiveness are made. By design, these experiments will involve highly effective dispersants applications, as well as moderately effective, slightly effective, and ineffective applications. Our objectives will be to: a) correlate the monitoring results with the measured levels of effectiveness to verify the usefulness of the monitoring protocols; and b) Determine the limitations of the protocols if any, in detecting low levels of effectiveness. In addition, the experiments will provide a data set that can be used in refining the protocols, if required.

The proposed work will:

Evaluate the results of the US at-sea trials,
Design a dispersant program at Ohmsett based on the results of the UK trials,
Conduct dispersant effectiveness experiments at Ohmsett under identical conditions to those in the UK trials,
Correlate the results of the Ohmsett experiments with data collected during the UK at-sea trials and from laboratory effectiveness tests,
Write a technical report and scientific paper on the results of this research project.

Latest progress update

UK at-sea dispersant effectiveness experiments were successfully conducted in June 2003, offshore the Isle of Wright, UK. MMS participated in these experiments. Results of these experiments were used to design a dispersant effectiveness test program at Ohmsett based on the UK sea trials. Effectiveness experiments were successfully done in October 2003 at Ohmsett facilities. Many participants observed the experiments. Identical oils (IFO-120, 180, and 380) and dispersants (Agma DR 379, Corexit 9500, Superdispersant 25) as well as identical dispersant-to-oil ratios, water temperatures and salinity were used in the tests.

In addition, the USCG Atlantic Strike Team and Oil Spill Response Limited, Southampton, UK used the experiments as training exercise for their dispersant monitoring protocol. Texas AM brought in new equipment to test and monitor equipment used by the response teams. Data from the experiment are being analyzed and draft report should be out in the spring of 2004.

MMS has shipped the test oils and dispersants to other agencies and companies so test can be conducted in smaller wave tanks and laboratory scale. When these experiments are completed, there should be a better understanding of the correlation and scale with dispersant performance under at-sea conditions.

This project is complete. The final results were presented at the 2005 International Oil Spill Conference. The final report is available from the Minerals Management Service in PDF on a CD that also contains more than 80 video clips that documents each dispersant experiment. The film clips are not imbedded in the final report that is downloadable in PDF format from the MMS website.