ImpEx - Environmental Impacts of Exhaust Gas Cleaning Systems
for the Reduction of SOx on Ships
General information about the ImpEx project
| ImpEx project | |
|---|---|
| Project sponsor | German Environment Agency (UBA) |
| Timeframe | 15/01/2020 – 15/07/2023 |
| Research focus | Environmental protection in maritime traffic |
| Project number | KT800.S.4.F&E.00002.00 |
| Project lead at BSH | Dr. Annika Krutwa |
Project description
International maritime shipping contributes to air pollution with its emissions of pollutants from the exhaust gas, especially in coastal areas and port cities. The responsible UN organisation IMO (International Maritime Organization) has established various regulations in MARPOL (International Convention for the Prevention of Marine Pollution from Ships) Annex VI to reduce emissions.
This project dealt with sulphur oxide emissions (SOx) according to Regulation 14 of MARPOL Annex VI. Compliance with the limit values specified there can be achieved by the fuel used (or the fuel quality) or by various technical processes in the exhaust gas system. Depending on the technology used, a reduction in air pollutant emissions can lead to undesirable discharges of pollutants into the marine environment. Previous research projects of the German Environment Agency (UBA publications 83/2014 and 162/2020) as well as international studies showed precisely this effect when scrubbers (Exhaust Gas Cleaning Systems - EGCS) are used.
From an environmental point of view, a shift of pollutant inputs from the air to the water, for example, is unacceptable. The Convention on the Law of the Sea also contains a prohibition on transfer and transformation with regard to pollution of the marine environment (Art. 195 UNCLOS).
The project focused on the analyses of scrubber discharge water and the evaluation of the current regulation. In this regard, an analysis of status quo based on a literature review was published in 2021 (Marin-Enriquez et al., 2021) within the framework of the project. A sampling and measurement campaign on board four ships equipped with scrubber hybrid systems was conducted with focus on the chemical characterisation and ecotoxicological effects of scrubber water samples, but also included the evaluation of the discharge water online monitoring and the characterisation of fuel and lube oil.
Project goal
The aim of the project was to support the international discussion process with regard to the scrubber discharge water with the scientific results obtained within the framework of the project, taking into account the concerns of marine environmental protection, and thus to contribute to the factualisation of the discussion in the relevant committees.
Project partners
- Hamburg Ministry of Environment, Climate, Energy and Agriculture,
- Federal Institute of Hydrology,
- Helmholtz-Zentrum hereon GmbH,
- Hamburg Institute for Hygiene and Environment,
- Shipping companies,
- German Environment Agency,
- University of Muenster
- Consultancy (Brigitte Behrends, Ph.D.),
and a manufacturer of measurement technology for scrubber discharge water.
Project results
- Heavy metals such as vanadium, nickel, copper, iron and zinc as well as organic pollutants, including polycyclic aromatic hydrocarbons and oil residues, were found in elevated concentrations in the discharge water samples.
- The whole effluent toxicity of the scrubber discharge waters ranged from practically non-toxic to considerably toxic for the open loop to extremely toxic for the closed loop operation mode samples. Further, almost all samples demonstrated mutagenic and the closed loop samples dioxin-like effects.
- The discharge water is acidic and contains persistent, bioaccumulative and toxic pollutants that may cause short- and long-term detrimental effects in the marine environment.
Thus, the release of scrubber discharge water from both operation modes into the sea is of high concern. Protective measures for the marine environment such as local or regional discharge bans are proposed.