Environmental Risk Assessment of Discharge Water from Exhaust Gas Cleaning Systems

Abstract

This study aimed to provide scientific evidence for the environmental risk of scrubber discharge water, considering the local Korean marine environment. In February and March, 2023, an exhast gas cleaning system (EGCS) was installed and operated to measure water quality parameters of the discharge water, analyze concentrations of harmful substances, and conduct an environmental risk assessment. Compared to the inflow water, solution pH and alkalinity of the discharge water decreased, and temperature and turbidity increased by 4.6℃. There was no significant change for salinity. Sixteen different types of polycyclic aromatic hydrocarbons were not detected in the inflow water, whereas 6 types were detected in the discharge water. The results of Ni, Cr, and V measurements revealed their consistent increase in discharge water. In the environmental risk assessment, phenanthrene was judged as a persistent bioaccumulative and toxic substance, but it was assumed that the environmental risk was low as there were no substances with RCR (Risk Characterization Ratio) values > 1. In summary, the environmental risk posed by open-loop EGCS discharge water used in this study is not considered to be high. This study adds evidence for the stability of EGCS use and provides basic data for future research.