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 
> Particularly, missing and unsuitable sampling points are reported 
7.4.2 Chemical composition 
Based on the results of the abovementioned studies the following general observations and 
conclusions can be stated regarding the chemical composition of EGCS discharge water: 
Trace metals are mainly found in dissolved form. This could be explained by acidic 
conditions and high levels of chloride in the water. Removal efficiency of metals relying only 
on mechanical treatment is therefore limited. 
Significant enrichment of vanadium and nickel in discharge water is observed. Both metals 
are found in residual fuel oils in high concentrations. 
Copper and zinc were also found in relevant concentrations in water samples (even in inlet 
samples). The materials of the sampling pipe, corrosion protection and antifouling systems 
may explain those irregularities. 
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> 
D- 
Nitrate levels in discharge water were generally found below the IMO discharge limit 
concentration and strongly dependent of the inlet water levels. Nitrite levels in OL samples 
were considered negligible. 
Dil concentration in OL discharge water was below 1 ppm, while oil in CL discharge water 
ranged between 2 -21 ppm (see Table A-4). 
Relation between oil content and PAHyne was assessed only by one research study. That 
study found a correlation between the parallel measurements of PAHyne and laboratory 
results for oil content (HOI) and PAHgpa16. The PAHpne values from the on-line monitoring 
data did not show a correlation with oil nor PAHgpra16. The use of PAHypne as a proxy 
parameter for oil content in EGCS discharge water should be further examined. 
Relation between turbidity, suspended solids, organic pollutants and metals was not 
assessed by any research work. The use of turbidity as criteria and proxy parameter for 
pollutants in EGCS discharge water should be examined. 
PAHera16 cConcentrations in discharge water were generally found below the IMO limit value 
given in PAHyne (this comparison is actually not consistent but serves to illustrate the PAH 
levels in EGCS discharge water). 
Naphthalene, phenanthrene and fluorene represented the highest fractions of the PAHepa16. 
PAHs with more rings were found in much lower levels, mainly below the detection limits. In 
CL discharge water samples, however, their presence was more notable even though the 
water treatment unit could remove them very efficiently. 
Petrogenic PAHs (fuel related) were more dominant in the discharge water rather than 
pyrogenic PAHs (combustion related). 
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