Electrochemical Cell Applications for Ballast Water Treatment

Abstract

A B S T R A C TThe transportation of exotic species in ballast tanks is one of the most important global environmental problems facing the shipping industry. Electrochemical techniques offer one of the most viable solutions for ballast water problems. This work reports laboratory experiments conducted by Istanbul Technical University (ITU) for the best and optimal electrochemical cell design for EU Project BaWaPla (Contract 031529), in which a new hybrid ballast water treatment system has been developed. The capability of an electrochemical system to effectively eliminate these organisms depends on various internal and external parameters. Five different electrochemical cells were assessed for the BaWaPla system. The variable parameters of the cell design were the geometry and dimensions of the electrodes. In additional to cell design, the effects of Ca 2+ and Mg 2+ concentrations, along with ammonia, were also investigated as external parameters for system capability. The results show that the enlargement of electrode surfaces result in increased chlorine concentrations in the disinfectant. On the other hand, suitable electrode and coating materials are essential for "reverse polarity" operation in order to avoid scaling of Ca 2+ and Mg 2+ ions on electrodes and clogging the membrane. Ammonia, if present in ballast water, has a negative effect on disinfection quality. Experiments show that presence of 7.8 mg/L ammonia in electrolyte may cause up to 73% loss of free available chlorine and 38% loss of total available chlorine concentrations. Measures should be considered, both in the design stage and during the disinfection process, to reduce the negative effect of ammonia.

Evaluating the biological efficacy of a ballast water management system using filtration and electro-catalysis with an accurate definition of holding time

“…At present, electro-chlorination is one of a number of BWMS technologies approved by the IMO and the United States Coast Guard (Goncalves & Gagnon 2012;Guney & Yonsel 2013). As of July 10th, 2019, there were 81 types of BWMS products approved by the IMO.…”

“…Both direct and indirect oxidation processes can destroy the cells of organisms in ballast water (Guney & Yonsel 2013). In electro-chlorination, chlorine, sodium hydroxide and hydroxyl ion are simultaneously generated as active substances of the disinfection process, together referred to as 'total residual chlorine' (TRC) (Guney & Yonsel 2013).…”

“…Both direct and indirect oxidation processes can destroy the cells of organisms in ballast water (Guney & Yonsel 2013). In electro-chlorination, chlorine, sodium hydroxide and hydroxyl ion are simultaneously generated as active substances of the disinfection process, together referred to as 'total residual chlorine' (TRC) (Guney & Yonsel 2013). In the process, some other oxidants are produced that are also capable of inactivating organisms, such as hydroxyl radicals (OH˙), hydrogen peroxide (H 2 O 2 ), and ozone (O 3 ) (Deborde and von Gunten 2008).…”

Determination of Sediment Accumulation Pattern in a Double Bottom Ballast Tank Model

“…The decision criteria for selecting ballast water treatment systems are generally based on the ship specifications or/and treatment system characteristics [7]. However the ballast water characteristics are also effective on the system performance [8]- [11] and these systems are mostly effective on organisms which are living in the water phase. On the other hand, ballast tanks of the ships cannot be completely emptied during de-ballasting [12].…”