title: Enhancing the efficacy of electrolytic chlorination for ballast water treatment by adding carbon dioxide.
abstract: We examined the synergistic effects of CO2 injection on electro-chlorination in disinfection of plankton and bacteria in simulated ballast water. Chlorination was performed at dosages of 4 and 6ppm with and without CO2 injection on electro-chlorination. Testing was performed in both seawater and brackish water quality as defined by IMO G8 guidelines. CO2 injection notably decreased from the control the number of Artemia franciscana, a brine shrimp, surviving during a 5-day post-treatment incubation (1.8 and 2.3 log10 reduction in seawater and brackish water, respectively at 6ppm TRO+CO2) compared with water electro-chlorinated only (1.2 and 1.3 log10 reduction in seawater and brackish water, respectively at 6ppm TRO). The phytoplankton Tetraselmis suecica, was completely disinfected with no live cell found at >4ppm TRO with and without CO2 addition. The effects of CO2 addition on heterotrophic bacterial growth was not different from electro-chlorination only. Total residual oxidant concentration (TRO) more rapidly declined in electro-chlorination of both marine and brackish waters compared to chlorine+CO2 treated waters, with significantly higher amount of TRO being left in waters treated with the CO2 addition. Total concentration of trihalomethanes (THMs) and haloacetic acids (HAAs) measured at day 0 in brackish water test were found to be 2- to 3-fold higher in 6ppm TRO+CO2-treated water than in 6ppm TRO treated water. The addition of CO2 to electro-chlorination may improve the efficiency of this sterilizing treatment of ballast water, yet the increased production of some disinfection byproducts needs further study.
authors.affiliation: South Sea Research Institute, Korea Institute of Ocean Science and Technology, 41 Jangmok-1gil, Jangmok-myun, Geoje-si 656-834, Republic of Korea; Department of Oceanography, Busan National University, 2 Busandaehak-ro 63beon-gil, Geumjeong-gu, Busan 609-735, Republic of Korea.
authors.forename: Hyung-Gon
authors.initials: HG
authors.lastname: Cha
authors.affiliation: South Sea Research Institute, Korea Institute of Ocean Science and Technology, 41 Jangmok-1gil, Jangmok-myun, Geoje-si 656-834, Republic of Korea.
authors.forename: Min-Ho
authors.initials: MH
authors.lastname: Seo
authors.affiliation: New Water Tech Co. Ltd., Unit 204 Sanhak-Kwan, Dongkuk St. 32, Ilsan-donggu, Goyang-si 410-820, Republic of Korea.
authors.forename: Heon-Young
authors.initials: HY
authors.lastname: Lee
authors.affiliation: Korea Testing & Research Institute, 411 Daun-dong Jung-gu, Ulsan 681-802, Republic of Korea.
authors.forename: Ji-Hyun
authors.initials: JH
authors.lastname: Lee
authors.affiliation: Department of Oceanography, Busan National University, 2 Busandaehak-ro 63beon-gil, Geumjeong-gu, Busan 609-735, Republic of Korea.
authors.forename: Dong-Sup
authors.initials: DS
authors.lastname: Lee
authors.affiliation: South Sea Research Institute, Korea Institute of Ocean Science and Technology, 41 Jangmok-1gil, Jangmok-myun, Geoje-si 656-834, Republic of Korea.
authors.forename: Kyoungsoon
authors.initials: K
authors.lastname: Shin
authors.affiliation: Department of Oceanography and Ocean Environmental Sciences, Chungnam National University, 99 Daehak-ro, Yusung-gu, Daejeon 305-764, Republic of Korea. Electronic address: keunhchoi@cnu.ac.kr.
authors.forename: Keun-Hyung
authors.initials: KH
authors.lastname: Choi
mesh_terms: D000818:Animals; D001419:Bacteria / Q000187:drug effects; D002245:Carbon Dioxide / Q000633:toxicity*; D002713:Chlorine; D004202:Disinfectants; D004203:Disinfection / Q000379:methods* / Q000706:statistics & numerical data; D004572:Electrolysis; D054879:Halogenation; D006863:Hydrogen-Ion Concentration; D008826:Microbial Sensitivity Tests; D016877:Oxidants; D010839:Phytoplankton; D010933:Plankton / Q000187:drug effects*; D012623:Seawater / Q000382:microbiology; D012767:Ships; D018508:Water Purification / Q000379:methods*
chemical_list: D004202:Disinfectants; D016877:Oxidants; D002245:Carbon Dioxide; D002713:Chlorine
keywords: Ballast water; Carbon dioxide; Electrochlorination; Synergistic effects