Development of an electrochemical antifouling system for seawater cooling pipelines of power plants using titanium

Abstract

Biofouling is the undesirable adhesion and development of microorganisms and macroorganisms in a water environment. An electrochemical antifouling system based on management of primary adhesion of microorganisms was developed employing titanium electrode for antifouling of seawater cooling pipes and marine infrastructures. The system consists of an electrochemical reaction-monitoring unit, a power control unit, and a potential/current remote monitoring and a control unit. Titanium plates and iron plates were used as the working and counter electrode, respectively. Field experiment was conducted in the seawater cooling pipeline system of a thermal power station. Four titanium electrodes with 1.0 m length and 3.0 m width were set in the seawater intake pit and current density was controlled at 50-100 mA/m(2). The electrode surface maintained clean conditions for 2 years. The average wet weight of fouling organisms on the titanium electrode surface was below 100 g/m(2) whereas the corresponding wet weight was above 10 kg/m(2) on the control surface. Using titanium as the electrode material, chlorine and hypochlorite are not generated. The developed electrochemical antifouling system provided an effective, environmentally friendly, and feasible techniques for remote operations.

Inhibition of barnacle (Amphibalanus amphitrite) cyprid settlement by means of localized, pulsed electric fields

“…Indeed, oxygen reduction and hydrogen peroxide production have been reported in anodically produced TiO 2 (Clechet et al 1979;Mentus 2004). Moreover, Wake et al (2006) presented a similar conclusion regarding the involvement of reactive oxygen species on electro chemical AF processes using titanium electrodes. Thus, further investigation of these systems is necessary in order to evaluate the importance of reactive oxygen species formation on the inhibition of barnacle settlement.…”

“…This energy value is higher than the one reported by Wake et al (2006) for an AF study using galvanometrically activated titanium plates in a field system (0.3-0.6 W h 71 m 72 or, equivalently, 50-100 mA m 72 of current with an average voltage of 6 V vs. Ag/AgCl reference electrode). Voltage drops occurring at the counter electrode were not reported in that study, thus a direct comparison with the present results cannot be established.…”

“…With an amplitude of 710 V, formation of a gold coloured layer on the titanium strips was observed. It is possible that this coloration was due to the development of an amor phous titanium oxide film (TiO 2 ), as reported by Wake et al (2006) on titanium electrodes used in electro chemical AF systems. Superficial electrode corrosion was unlikely to happen with 10-V PEFs on 25 mm electrodes; otherwise, electrode trans-passivation would have produced increased current flows due the migration of titanium ions into the liquid medium, but current measurements did not show evidence of such phenomenon.…”

Bacterial adhesion: From mechanism to control

“…However, the detached bacteria could again accumulate on the surface, which caused prolongation of bacterial adhesion. On the other hand, direct electron transfer between bacteria and the anode surface has been applied to prevent microbial adhesion, biofilm growth, and marine biofouling [170,172,173]. When an anodic current or potential is applied, inactivated bacteria tend to remain on the surface.…”

Effects of polarization in the presence and absence of biocides on biofilms in a simulated paper machine water

“…In saline waters electrochemical polarization can generate biocidally active chlorine species (Cl 2 , HCl, OCl ¡ , and ClO 2 ) that are most likely responsible for the reported antimicrobial activity and antifouling in marine applications [16,28]. We found that electrochemical polarization was eVective also in brackish Baltic Sea water (3 g NaCl l ¡1 ) used as cooling water in heat exchangers of a power plant [13].…”