Modelling of discharges from Baltic Sea shipping

Abstract

Abstract. 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.

Nutrient Analysis of Food Waste from Ships’ Greywater in the Baltic Sea

“…Thus, the total sum of these daily nutrient content (DNC) calculation options was used to determine the total amount of these substances. This parameter depended on the amounts of catering waste produced by the different numbers of persons on each type of ship and the amounts of greywater produced by the different numbers of persons on all types of ship [31]. In the worst-case food waste management scenario, a ship discharges a mixture of food waste and greywater when the DNC has been generated.…”

“…In the food waste management scenario in which only food waste is discharged into the sea, DNC B contributes 10 g•day −1 of phosphorus and 34 g•day −1 of nitrogen to the sea. Nutrient emission factors from literature sources [30,31] were used in these calculations.…”

Framework for the environmental impact assessment of operational shipping

“…Prior to the Pressures from releases of scrubber wash water; use of exhaust gas scrubbers is an alternative to use of fuels with low sulphur content BONUS SHEBA framework, the use of AIS data to assess marine pollution from shipping had only been applied to model the indirect contribution from shipping emissions through atmospheric deposition. Within this framework, the very first complete inventory and calculation of load factors of waste streams and the sum of pollutants from all waste streams from shipping in the Baltic Sea has been achieved (Jalkanen et al 2021a). The development of the underwater noise source module of STEAM is the first attempt to indicate the levels of noise emitted by ships based on actual traffic patterns of AIS, advancing our knowledge of spatio-temporal variation of shipping noise and increasing general knowledge of ships as a source of noise pollution (Jalkanen et al 2018).…”

“…In this framework, we apply the state-of-the-art methodology based on ship traffic activities, derived from ship position data transmitted in high temporal resolution via AIS (Automatic Identification System) signals. The total amount of air pollutant emissions and discharges to sea as well as of underwater noise emitted from ships sailing in the Baltic Sea region are calculated in a consistent manner with the STEAM model (Jalkanen et al 2009(Jalkanen et al , 2012(Jalkanen et al , 2018(Jalkanen et al , 2021a. The model combines shipping activities with emission factors for air pollutants sulphur and nitrogen oxides, particulate matter, carbon monoxide (SO X , NO X , PM, CO) and CO 2 .…”

“…Both can then be used to evaluate different policy options. While the detailed methodology and results are described elsewhere (Jalkanen et al 2018(Jalkanen et al , 2021aKarl et al 2019a, c;Maljutenko et al 2021;Ramacher et al 2020a, b;Raudsepp et al 2019a;Tang et al 2020;Ytreberg et al 2020), the framework concept is presented here together with the main knowledge gaps and an outline of a possible further development of the framework. The framework was elaborated for the case of the Baltic Sea region, but it is generic and can be applied to other geographic regions and/or for global assessments.…”