The problems start when this water, which may have been taken on board in far-flung places, is released in ports thousands of miles away – microorganisms, plants, worms and crustaceans gain a foothold in a new environment and often out compete the local flora and fauna. The results can be devastating, with wholesale collapses in the populations of local wildlife.

 

And it’s not a new problem - scientists first noted the signs of an alien species probably introduced in this way after a mass occurrence of the Asian phytoplankton algae Odontella (Biddulphia sinensis) in the North Sea in 1903.

 

Fortunately, the world has woken up to the issue and there are now strict regulations in place to prevent the spread of invasive organisms from ballast water.

Under the Ballast Water Management (BWM) Convention, a ballast water management system (BWMS) must meet a performance standard based on agreed numbers of organisms per unit of volume.

There are numerous ways to control organisms – physical barriers, chemical disinfection, heat treatment and ultraviolet are just a few.

 

Whatever method is chosen, it is vital to control the flow of ballast water throughout the stages of the system and discharge it according to the guidelines.

 

This is achieved by using a series of valves. Positioning them reliably is critical to ensure the overall system works as intended and so valve positioners are essential.

 

Valves are likely to be working close to pumps and other heavy machinery, so the positioners you choose need to be robust. Conditions will be wet so quality materials are also important. ABB’s entry level TZIDC positioners have an aluminium housing, for example, while the top-of-the-range EDP300 uses stainless steel to offer the best possible long-term protection - a high IP rating is also a good idea.

BWMS applications may also face severe restrictions on space and accessibility – to meet this need, ABB’s compact positioners are no bigger than a shoebox. The health and safety of operators is also of prime concern. The TZIDC-Remote and the EDP300-Remote allow the operator to use an HMI in a more accessible and safe area, making it much easier to monitor the system and adjust settings.

 

It’s vital to consume the minimum of resources on long voyages. ABB’s pneumatically driven positioners offer the lowest steady state compressed air consumption on the market. At less than 0.03 kg/h (0.015 scfm), this delivers large energy savings and a lower lifetime cost of ownership.

 

When ships are operating far from their home ports, maintenance also needs to be minimized – ABB positioners offer accurate control to avoid overshoots and so reduce wear on the system. The positioners are also modular, making it an easy job to fit new parts when needed. 

 

And if your vessel does run into trouble in a remote part of the world, you’ll be glad of a supplier who can act locally – ABB has a global network of partners that can respond if needed.

The key to controlling invasive species lies in a good BWMS – and effective and efficient valve positioners play a vital role in protecting the marine environment.