The system uses the company’s inert gas based GLDTM treatment plant to meet the needs of large bulk carriers, which often ship large volumes of ballast water in upper wing tanks.
Andrew Marshall, Coldharbour Marine’s Chief Executive, explains that most system technologies work by treating the ballast water at the point it is taken on board at the cargo discharge port and usually incorporate a filtration process and chemical dosing. Delays during ballast loading due to filtration issues or system breakdown are only one of the potential pitfalls, he says.
However, the new system is not an in-line process, but an in-voyage process, so there are no filters and no potential problems relating to flow rates, pressure drops, or power consumption during ballasting.
In addition, the solution is especially appropriate for bulk carriers because it addresses stability issues specific to the ship type, Mr. Marshall explains. For example, bulkers sometimes load extra ‘heavy weather’ ballast water in cargo holds, which inevitably faces contamination by cargo residues. In-line systems would find this water hard to process and could be damaged by it.
In this case, Coldharbour has developed a pipe circuit to allow ballast to be pumped from the various tanks through robust gas lift diffusion (GLD) units mounted in the machinery space - instead of in-tank, meaning that water can be returned to the tanks via multiple outlets to ensure that contents are stirred and treated.
“Now that the IMO’s Ballast Water Convention has entered force, vigilant port states will be watching bulk carrier operators closely,” Marshall says. “Operators of these vessels have no time to lose in assessing how they will meet Convention requirements.”