Netherlands-based Damen has developed a high flow rate pre-filtering process to prepare water in high sediment rivers and ports before it enters a ship’s ballast water treatment system
When a vessel is not fitted with a one-pass ballast water treatment system, sediment can overwhelm the system, forcing the filters to backflush and slow down cargo operations, delaying the vessel in port. It is one of the main complaints shipowners make about ballast water treatment systems.
Damen Shipyards Group has unveiled a Ballast Water Pre Filtration Barge (BWPF) to assist vessels in complying with IMO’s Ballast Water Management Convention (BWMC).
Many ports located on rivers throughout the world experience a sediment level significantly higher than the level onboard ballast water treatment systems are tested to. Damen Green Solutions’ product portfolio manager Matthijs Schuiten explained “The level to which onboard systems are tested demonstrates an ability to handle sediment levels up to 50 mg per litre. However, at some terminals, this level is exceeded – sometimes considerably. We recently ran tests on a waterway in the US close to a harbour, for example, and found sediment levels 30 times above this.”
Important waterways that exceed the level to which onboard systems are tested include the Huangpu Jiang in Shanghai, the River Thames in London and the Red and Mississippi rivers in the US.
“Such high levels of sediment can cause ballast water filter blockage,” Mr Schuiten said. “This can make for huge operational challenges, preventing cargo unloading or ballast water intake.”
Damen’s answer is the BWPF barge, designed to go alongside a vessel at a terminal and filter the sediment before ballast water is taken aboard.
Mr Schuiten said “Pre-filtering the water in this manner ensures the ballast water system on board is not blocked due to sediment. Having such capabilities enables terminals to add value for calling vessels. With the IMO legislation’s passage into law, we expect to see demand for such services in the near future. Developing the BWPF Barge is Damen’s way of making sure that, when the need arises, we are prepared to respond quickly.”
The BWPF barge can process up to 4,000 m3 water per hour with a sediment level between 50 and 1,500 mg per litre. Filtration is available between 10 and 50 microns, to suit varying sediment sizes. The entire ballast water filtration system fits neatly inside a standard 40 ft container, making logistics straightforward.
The BWPF barge is Damen’s latest contribution to dealing with difficult ballast water treatment problems. In 2019, the company unveiled a new version of its containerised ballast water treatment system, which can be moved around a port to treat ballast water from vessels whose own system is inoperable or fails to treat to the required standard.
Ballast water treatment does not stop with compliance. Industry’s stakeholders discuss the issues in the Ballast Water Treatment Beyond Compliance webinar, which is now available to view.