Enhancing the efficacy of electrolytic chlorination for ballast water treatment by adding carbon dioxide

Cyanide oxidation by singlet oxygen generated via reaction between H 2 O 2 from cathodic reduction and OCl − from anodic oxidation

“…Electro-chlorination is one of the most cost-effective and widely adopted approaches for disinfection and purification of water [12]. In this method, active chlorine could be generated by passing direct current through electrodes within an electrolytic cell in the presence of salts as electrolytes.…”

Which Ballast Water Management System Will You Put Aboard? Remnant Anxieties: A Mini-Review

“…Based on both the dissociation reaction of the HOCl (Table 2) and Le Chatelier's principle, the formation of HOCl will be diminished because of a shift of equilibrium toward the formation of hypochlorite ion (OCl − ) [43,44]; and, given that OCl − is a disinfectant agent several times less active than HOCl, it is expected that electro-chlorination efficiency of natural seawater always will be impaired due its relatively low [H + ]. Actually, the pH problem related to the effectiveness of electro-chlorination in natural seawater raises additional technical concerns, and additional procedure, such as carbonation (reaction showed Table 2), i.e., direct injection of carbon dioxide gas (CO 2 ) into ballast water is used to maintain low ballast water pH, i.e., higher [H + ] [45]. However, extra and necessary equipment must be properly installed and the process controlled and monitored.…”

Long-term Changes of Disinfection Byproducts in Treatment of Simulated Ballast Water

“…E-mail: pgjang@kiost.ac.kr over time, but it is sufficiently stable to react with and kill or inactivate organisms. However, the TRO produced by electrolysis can generate residues and reacts with organic matter in water to produce disinfection by-products (DBPs) which can adversely affect marine ecosystems (Delacroix et al 2013;Werschkun et al 2014;Cha et al 2015;Gonsior et al 2015;Lee et al 2017;David et al 2018). Therefore, BWMSs that use active substances, including chlorine, must be approved by the Marine Environment Protection Committee (MEPC) according to regulation G9 of the Convention.…”

“…Classes of DBPs observed in chlorinated water include trihalomethanes (THMs), haloacetic acids (HAAs), haloacetonitriles (HANs), halonitromethanes (HNMs), haloketones (HKs), and chloral hydrate. Although DBPs associated with the freshwater chlorination of drinking water have long been a topic of research, studies of the effects of the formation of DBPs by brackish or seawater chlorination have recently become more common because of increased interest in ballast water treatment and seawater desalination (Delacroix et al 2013;Cha et al 2015;Gonsior et al 2015;Shah et al 2015;Lee et al 2017;Park et al 2017;David et al 2018). The formation of DBPs is considered problematic in oxidizing-water disinfection (von Guntten 2018).…”

“…The amount of organic DBPs in chlorinated ballast water is mainly dependent on the oxidant type and dosage and on the type and concentration of natural organic matter in the local ballast water (Gonsior et al 2015;Shah et al 2015;Liu et al 2018). In addition, the type and concentration of DBPs during seawater disinfection have been found to depend on the temperature, salinity, bromide, iodide and the pH (Hua et al 2006;Zhang et al 2013b;Kim et al 2015;Shah et al 2015;Cha et al 2015;Yu et al 2015). Thus, the environmental changes in the tank where ballast water treated with BWMS are stored can affect DBP concentrations.…”