- Email: [email protected]
Dispersant effectiveness seminar, Oslo, Norway, May 1985
Oil & Petrochemical Pollution 2 (1985) 311-313
Conference Reports Dispersant Effectiveness Seminar, Osio, Norway, May 1985
An international seminar on dispersant effectiveness was held in Oslo on 8-9 May 1985. The seminar was organised by the Center for Industrial Research (SI), and sponsored by the State Pollution Control Authority (SPCA) and Norwegian Oil Pollution Control Research and Development Program (PFO). Thirty-five delegates from universities, research institutes, oil companies and governmental organisations in Canada, USA, England, France, The Netherlands, Germany and Norway participated. The seminar was organised into three sessions covering laboratory and small scale field tests, large scale field trials and real spill cases. The first session discussed the possibilities and limitations of effectiveness studies in laboratory and small scale field trials. Keynote lectures were held by Dr D. Mackay, University of Toronto, on the mechanisms and mathematical modelling of the chemical dispersion processes. The knowledge of the mechanism of the dispersion processes is today n o t well enough understood. It is believed that a better understanding of the mechanism will help in establishing models for quantifying dispersion effectiveness. Once a validated equation is available, it will greatly facilitate the comparison of results between laboratory test systems and particularly between field and laboratory tests. Presentations at the seminar showed that that there is still a lack of correlation both between existing laboratory tests and between laboratory and field tests. Other presentations in this session of the seminar demonstrated the work carried out in the develop-
ment of new laboratory procedures which may give some more realistic information about field conditions. Droplet size distributions of dispersions are of importance in estimating different type of mixing mechanisms, which may explain the lack of correlation between different laboratory tests. Furthermore, continuous dilution test systems seem to give a better simulation of the dynamic conditions in the field. Recent studies also indicate that the chemical composition of oils, such as the content of indigenous surfactants, may cause great differences in dispersant performance. The second session comprised the experiences of large scale field trials carried out in France, Norway and The Netherlands in recent years. The results of these trials, to enhance dispersion with chemical dispersant, showed a mixed success. Representative measurement in the water column under the slicks is a practical problem which may be o n e explanation of different effectiveness results. Furthermore, an extensive use of remote sensing aircraft seems to be of advantage both in evaluating the success of the spraying operation and for long term studies (2-3 days) of the slick development. It was recommended that effectiveness evaluation (mass balance) should be based on quantification of the remaining surface oil instead of measuring the dispersed oil. Furthermore, the spraying operation seems to be very critical in order to optimise the effective (actual) dispersant-to-oil ratio on an unhomogeneous oil slick. In future more studies are needed on the herding effect and on the mixing of dispersant into surface oil.
Oil & Petrochemical Pollution 2 (1985)--© Elsevier Applied Science Publishers Ltd, England, 1985. Printed in
Great Britain 311
312
CONFERENCE REPORTS
The last session of the seminar covered presentations of recent real spill cases where dispersants have been applied. Examples were given from the U K and Ireland, two countries that not only have experienced large spills from time to time, but have also tended to rely on dispersants. Incidents like the Olympic Alliance in 1975, the Eleni V in 1978, the Betelgeuse in 1979 and the Silvand accident in 1983 are cases where dispersants have been used with different success. Highly viscous and weathered oil, low performance dispersants, inefficient application methods and other operational problems are among those factors which have limited the successful use of dispersant in some of these cases. More
OPP VOL. 2 NO. 4, 1985
effort is required to obtain quantitative data of the dispersant effectiveness in future oil spills. The seminar provided a stimulating forum for exchange of ideas. The lectures provided an important basis for discussions on the application and effectiveness of dispersants, which also led to a recommendation for future research work both in the field and the laboratory. For those interested, a report (25 pages) from this seminar is available on request.
Per S. Daling Center for Industrial Research, PO Box 350, Blindern, 0314 Oslo 3, Norway
ADERMA* Colloquium An interesting colloquium was held in Bordeaux in early October 1985. It was organised by the Aquitaine Association for the Development of Marine Research. Aquitaine is the French region which consists largely of the west-facing Atlantic coast, from the Spanish border to the Gironde estuary. It consists of five D6partements--many well known to holiday-makers--Dordogne, Gironde, Landes, Lot-et-Garonne and Pyr6n6es Atlantiques. The object of the colloquium was to study the problems of the coastal zone from the coastal fringe to the edge of the Continental shelf and to find out how best to protect the area. The meeting adopted a slightly unusual procedure. The topics for each session were defined and three or four persons, expert in the various aspects, were asked to open a discussion, but not to give a lecture. Most of the members of the meeting (about a hundred) had sent in a written contribution on some aspect of the subject, and these had been summarised and distributed to everyone before the *ADERMA: Association Aquitaine pour le Developpment des Recherches Marines.
meeting started. There was not a Chairman but two Secretaries/Moderators who controlled each session. The success of the scheme depended on the experts. Some did, indeed, just introduce their topic and then invite audience response while others lectured and left little time for other views. The first session, which laid down the background by discussing the earth/sea interface, was opened by an oilfield geologist, an oceanographer and a professor of marine biology. The second session dealt with the general effect of people, residents, or visitors to the zone, and of agriculture, industry and tourism. The third session considered the effects of spills and discharges of oil and chemicals, dredging wastes, etc. The fourth session dealt with the protection, both of the coast and of the 200-mile economic zone, by laws, both national and international. The fifth session considered ports and harbours, including hydraulic and sedimentation problems, and this moved logically into the next session which dealt with exploration and exploitation of the resources of the continental shelf on the ocean bed, dealing largely with the highly valuable fishing and marine culture industries.
Conference Reports Dispersant Effectiveness Seminar, Osio, Norway, May 1985
An international seminar on dispersant effectiveness was held in Oslo on 8-9 May 1985. The seminar was organised by the Center for Industrial Research (SI), and sponsored by the State Pollution Control Authority (SPCA) and Norwegian Oil Pollution Control Research and Development Program (PFO). Thirty-five delegates from universities, research institutes, oil companies and governmental organisations in Canada, USA, England, France, The Netherlands, Germany and Norway participated. The seminar was organised into three sessions covering laboratory and small scale field tests, large scale field trials and real spill cases. The first session discussed the possibilities and limitations of effectiveness studies in laboratory and small scale field trials. Keynote lectures were held by Dr D. Mackay, University of Toronto, on the mechanisms and mathematical modelling of the chemical dispersion processes. The knowledge of the mechanism of the dispersion processes is today n o t well enough understood. It is believed that a better understanding of the mechanism will help in establishing models for quantifying dispersion effectiveness. Once a validated equation is available, it will greatly facilitate the comparison of results between laboratory test systems and particularly between field and laboratory tests. Presentations at the seminar showed that that there is still a lack of correlation both between existing laboratory tests and between laboratory and field tests. Other presentations in this session of the seminar demonstrated the work carried out in the develop-
ment of new laboratory procedures which may give some more realistic information about field conditions. Droplet size distributions of dispersions are of importance in estimating different type of mixing mechanisms, which may explain the lack of correlation between different laboratory tests. Furthermore, continuous dilution test systems seem to give a better simulation of the dynamic conditions in the field. Recent studies also indicate that the chemical composition of oils, such as the content of indigenous surfactants, may cause great differences in dispersant performance. The second session comprised the experiences of large scale field trials carried out in France, Norway and The Netherlands in recent years. The results of these trials, to enhance dispersion with chemical dispersant, showed a mixed success. Representative measurement in the water column under the slicks is a practical problem which may be o n e explanation of different effectiveness results. Furthermore, an extensive use of remote sensing aircraft seems to be of advantage both in evaluating the success of the spraying operation and for long term studies (2-3 days) of the slick development. It was recommended that effectiveness evaluation (mass balance) should be based on quantification of the remaining surface oil instead of measuring the dispersed oil. Furthermore, the spraying operation seems to be very critical in order to optimise the effective (actual) dispersant-to-oil ratio on an unhomogeneous oil slick. In future more studies are needed on the herding effect and on the mixing of dispersant into surface oil.
Oil & Petrochemical Pollution 2 (1985)--© Elsevier Applied Science Publishers Ltd, England, 1985. Printed in
Great Britain 311
312
CONFERENCE REPORTS
The last session of the seminar covered presentations of recent real spill cases where dispersants have been applied. Examples were given from the U K and Ireland, two countries that not only have experienced large spills from time to time, but have also tended to rely on dispersants. Incidents like the Olympic Alliance in 1975, the Eleni V in 1978, the Betelgeuse in 1979 and the Silvand accident in 1983 are cases where dispersants have been used with different success. Highly viscous and weathered oil, low performance dispersants, inefficient application methods and other operational problems are among those factors which have limited the successful use of dispersant in some of these cases. More
OPP VOL. 2 NO. 4, 1985
effort is required to obtain quantitative data of the dispersant effectiveness in future oil spills. The seminar provided a stimulating forum for exchange of ideas. The lectures provided an important basis for discussions on the application and effectiveness of dispersants, which also led to a recommendation for future research work both in the field and the laboratory. For those interested, a report (25 pages) from this seminar is available on request.
Per S. Daling Center for Industrial Research, PO Box 350, Blindern, 0314 Oslo 3, Norway
ADERMA* Colloquium An interesting colloquium was held in Bordeaux in early October 1985. It was organised by the Aquitaine Association for the Development of Marine Research. Aquitaine is the French region which consists largely of the west-facing Atlantic coast, from the Spanish border to the Gironde estuary. It consists of five D6partements--many well known to holiday-makers--Dordogne, Gironde, Landes, Lot-et-Garonne and Pyr6n6es Atlantiques. The object of the colloquium was to study the problems of the coastal zone from the coastal fringe to the edge of the Continental shelf and to find out how best to protect the area. The meeting adopted a slightly unusual procedure. The topics for each session were defined and three or four persons, expert in the various aspects, were asked to open a discussion, but not to give a lecture. Most of the members of the meeting (about a hundred) had sent in a written contribution on some aspect of the subject, and these had been summarised and distributed to everyone before the *ADERMA: Association Aquitaine pour le Developpment des Recherches Marines.
meeting started. There was not a Chairman but two Secretaries/Moderators who controlled each session. The success of the scheme depended on the experts. Some did, indeed, just introduce their topic and then invite audience response while others lectured and left little time for other views. The first session, which laid down the background by discussing the earth/sea interface, was opened by an oilfield geologist, an oceanographer and a professor of marine biology. The second session dealt with the general effect of people, residents, or visitors to the zone, and of agriculture, industry and tourism. The third session considered the effects of spills and discharges of oil and chemicals, dredging wastes, etc. The fourth session dealt with the protection, both of the coast and of the 200-mile economic zone, by laws, both national and international. The fifth session considered ports and harbours, including hydraulic and sedimentation problems, and this moved logically into the next session which dealt with exploration and exploitation of the resources of the continental shelf on the ocean bed, dealing largely with the highly valuable fishing and marine culture industries.