It is known that without protection, a submerged steel surface will gradually corrode, that is why steel quay walls are generally fitted with sacrificial anodes. Although, there is an alternative protection method: using anodes that are charged with ‘impressed current’.
In fact, at the HES Hartel Tank Terminal in the port of Rotterdam, no fewer than 2 km of steel quay wall are currently being protected via this method, which is more sustainable and ‘smarter’ than conventional anodes.
In this approach, the anodes are connected to a power source that puts them under a constant low voltage charge (called ‘impressed current’) and does not dissolve them.
“This current is entirely harmless, by the way. It amounts to four or five volts – comparable to two penlight batteries” explains Ruurd Dijkstra, project leader at Van der Heide, one of the market leaders in the field of cathodic protection systems (the general term for this type of protection).
Impressed current has been around for a few decades, but up till now it hadn’t seen too many large-scale applications in the port of Rotterdam. ‘But that’s about to change,’ predicts Duvaloois. ‘This technology aligns perfectly with our strategy to develop into the world’s smartest and cleanest port.’
According to the port, since the anodes don’t have to be replaced after installation, you ultimately consume far fewer raw materials. This significantly reduces your carbon footprint while there’s the additional advantage of far less maintenance.