Modelling of discharges from Baltic Sea shipping

This paper describes the new developments of the Ship Traffic Emission Assessment Model (STEAM) which enable the modelling of pollutant discharges to water from ships. These include nutrients from black/grey water discharges as well as from food waste. Further, the modelling of contaminants in ballast, black, grey and scrubber water, bilge discharges, and stern tube oil leaks are also described as well as releases of contaminants from antifouling paints. Each of the discharges is regulated by different sections of the IMO MARPOL convention, and emission patterns of different pollution releases vary significantly. The discharge patterns and total amounts for the year 2012 in the Baltic Sea area are reported and open-loop SOx scrubbing effluent was found to be the second-largest pollutant stream by volume. The scrubber discharges have increased significantly in recent years, and their environmental impacts need to be investigated in detail.

Automated summary

This paper describes the new developments of the Ship Traffic Emission Assessment Model (STEAM) which enable the modelling of pollutant discharges to water from ships. Each type of discharge is regulated by different sections of the IMO MARPOL convention, with varying emission patterns and total amounts reported for the year 2012 in the Baltic Sea area. Open-loop SOx scrubbing effluent was found to be the second-largest pollutant stream by volume, indicating a significant increase in scrubber discharges in recent years. The environmental impacts of these discharges need to be investigated in detail.