The last restrictions on shipping caused by the water pollution were lifted a month ago. Quay walls, jetties, buoys and poles can in general be cleaned, as these surfaces can be sprayed with cleaning agents directly under high pressure. At the moment, cleaning is still focussed on those sections of the port infrastructure that have not yet been cleaned as they did not restrict shipping from and to the terminals concerned.
With respect to the slopes, the slope elements are often soiled not only along the top, but also on the sides and bottom of the stone. In addition, the filter layer (rubble layer on which the stone is placed) is also contaminated. Cleaning the slope is done by means of a combination of high-pressure spraying and flushing with hot (90°) water. This method turned out to be extremely effective in previous clean-up operations. The reasons that this method will not achieve the envisaged solution under these circumstances are the oil type - heavy fuel oil - and the fact that the oil was spilled more than a month ago, with the result that much of the volatile components have evaporated. Along certain sections of the slopes, replacing the slopes is cheaper than cleaning.
The current understanding is that the entire clean-up operation will last until the middle of next year. The port of Rotterdam has almost 75 kilometres of quay wall and more than 200 kilometres of slopes.