TEXTE Environmental Impacts of Exhaust Gas Cleaning Systems for Reduction of SOx on Ships — Analysis of status quo 
Report compiled within the framework of the project ImpEx 
Zinc concentrations were in a similar range in the inlet samples, EGCS discharge 
water and harbour samples. A similar pattern was observed for arsenic. Cadmium 
resulted below detection limit in all locations. 
N 
All average metal concentrations in the inlet resulted above the levels reported for 
*he open sea. 
Kjglholt et al. (2012) (in Table A-4 presented as COWI) from the consulting group COWI A/S 
carried out a study on behalf of the Danish Environmental Protection Agency. In this project, 
discharge water (from OL and CL) and sludge (from CL) from the hybrid EGCS on board the 
RoRo vessel Ficaria Seaways was analysed to assess the impacts of EGCS discharge water on the 
marine environment and to evaluate the options for sludge treatment and disposal. The ship is 
in service in the Kattegat area and North Sea. Some of the main findings and discussions 
highlighted in the report regarding the chemical characterization of the discharge water are: 
a Vanadium and nickel were significantly enriched in both operation modes. 
Higher concentrations of copper and zinc were presumably caused from the material 
of the sampling point, since both metals were not detected in the fuel oil. 
Enrichment of sulphur in the discharge water was detected even in OL mode. 
Concentrations of PAH and total hydrocarbons (THC) were low in OL mode. In CL 
mode higher concentrations were observed. 
COD outlet concentrations (46 - 56 mg/L) in OL mode were slightly above the inlet 
concentration (44 mg/L). Higher levels (440 - 490 mg/L) are reported in the CL 
mode despite the partial reduction during water treatment (centrifugation). 
There was a significant reduction of suspended solids in water treatment 
(centrifugation) step in CL mode. 
m The level of some pollutants in EGCS discharge water exceeded the compared EQS. 
The OL results shown in Table A-4 are from samples taken downstream the scrubber tower (no 
dilution water). In the CL mode, the system was operated in a non-steady state (discontinuous) 
way. The water was initially recirculated and pollutant-enrichment was measured during two 
hours. The values presented in Table A-4 correspond to the samples taken after that time. 
Measurements of suspended solids at time intervals of 20 minutes demonstrated, however, that 
‘he saturation point was not reached after these two hours. 
A particularity of this study was the analysis of the sludge from the CL operation. There, 
vollutants were found in a more concentrated form than in the discharge water. Additionally, 
dioxin/furans were found in a relatively low concentration and PCBs were not detected. Based 
on the presence of vanadium, nickel and THC, sludge should be classified as hazardous waste. 
Additionally, the potential impact of EGCS discharge water to the marine environment was 
evaluated by using a simplified dispersion modelling in two areas (Kattegat Sea and Aarhus 
Bight) under different scenarios. Pollutant levels were generally found far below EQS, but in 
ports pollutant concentrations may be close or even slightly exceed levels of concern. The 
prohibition of EGCS discharge water in ports is suggested as precautionary approach. 
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