• Journal of the Korean Society of Marine Environment & Safety
• /
• v.24 no.2
• /
• pp.203-214
• /
• 2018

Ballast water treated by sodium dichloroisocyanurate (NaDCC) injection method in ballast water management system (BWMS) contains reactive bromine, chlorine species and disinfection by-products (DBPs). In this study, we conducted whole effluent toxicity (WET) testing and ecological risk assessment (ERA) to investigate its ecotoxicological effects on the marine environment. WET testing was carried out for eight marine and fresh water organisms, i.e. diatom, Skeletonema costatum, Navicula pelliculosa, green algae, Dunaliella tertiolecta, Pseudokirchneriella subcapitata, rotifer, Brachionus plicatilis, Brachionus calyciflorus and fish, Cyprinodon variegatus, Pimephales promelas. The WET test revealed that diatom and green algae were the only organisms that showed apparent toxicity to the effluent; it showed no observed effect concentration (NOEC), lowest observable effect concentration (LOEC) and effect concentration of 50 % (EC50) values of 25.0 %, 50.0 % and over 100.0 %, respectively, in seawater conditions. In contrast, rotifer and fish showed no toxicities to the effluent in the all salinity conditions. Meanwhile, chemical analysis revealed that the BWMS effluent contained total of 25 DBPs such as bromate, isocyanuric acid, formaldehyde, chloropicrin, trihalomethanes (THMs), halogenated acetonitriles (HANs) and halogenated acetic acids (HAAs). Based on ERA, the 25 DBPs were not considered to have persistency, bioaccumulation and toxicity (PBT) properties. The ratio of predicted environmental concentration (PEC) to predicted no effect concentration (PNEC) of the all DBPs did not exceed 1.0 for general harbour environments, but isocyanuric acid, tribromomethane, chloropicrin and monochloroacetic acid exceed 1.0 for near ship environments. However, when NOEC (25.0%) of the WET test results where actual effluent was applied, it was concluded that the NaDCC injection method did not have unacceptable ecological risks to the general harbor including near ship environments.

• Journal of Korean Society of Environmental Engineers
• /
• v.32 no.10
• /
• pp.965-972
• /
• 2010

The objective of this research was to evaluate for the changes of pore structures and adsorption capacities due to the increase the numbers of reactivation. The reactivated GAC had experienced three cycles of water treatment and thermal reactivation. The pore size distributions of virgin and reactivated GACs were very different. The virgin GAC was mostly microporous (< $15\;{\AA}$), with less mesopores ($20{\sim}100\;{\AA}$). The reactivated GACs was mostly mesoporous ($20{\sim}100\;{\AA}$), with less micropores (< $15\;{\AA}$). The specific surface area and total pore volume were reduced as the number of reactivation increased. The maximum adsorption capacity (X/M) of virgin GAC ($964.6\;{\mu}g/g$) for $CHCl_3$ was 2~3 times larger than 1st~3rd reactivated GAC ($255.6{\sim}399.5\;{\mu}g/g$). The maximum adsorption capacity (X/M) of virgin GAC (19.5 mg/g) for DOC (dissolved organic carbon) was equal to that of 1st~3rd reactivated GAC (18.0~18.7 mg/g).