Taking the bugs from the ballast
5 min read
10 Jan 2017
5 min read
10 Jan 2017
Whether it’s the North American comb jellyfish devastating the Black Sea fishing industry, Chinese mitten crabs accelerating erosion in the Thames estuary, or zebra mussels from Bulgaria clogging up the water intake of US power stations, invasive species are a huge global problem.
At any time, the world’s merchant ships are carrying different species in their ballast tanks, sucking them up whenever they take on ballast water, and then releasing them on the other side of the world.
“It can have a massive effect of the ecology of an area,” says Joe Thomas, Wärtsilä’s director of Ballast Water Management Systems. “It’s been identified as one of the biggest threats to the world’s coastlines.”
The annual cost in terms of increased maintenance, destruction of fishing stocks, blockage of industry inlets, erosion and other issues, comes to EUR 12 billion per year in Europe alone, according to figures from the European Union.
Thankfully, a full 12 years after the IMO’s 2004 Ballast Water Convention first was signed, and 120 years after steel vessels made ballast water necessary, regulations are coming through to combat the problem.
In September, when Finland ratified the convention, it added enough to the total tonnage of vessels from ratifying countries to surpass the threshold required – at least 35% of the total tonnage of world’s merchant fleet – to bring the convention into force.
Beginning 8 September 2017, every ship above 400 Gross Registered Tonnes (GRT) – an estimated 34,000 ships – will have to install a type-approved ballast treatment system at their next mandatory IOPP survey, often coinciding with a vessel’s five-year dry-docking inspection cycle. Thomas estimates the “massive demand” will require an investment between EUR 12–13 billion.
“The ratification is a very big milestone,” he says.
Once an alien species is introduced, it is almost impossible to eradicate. Often, the best solution is to introduce a predator that can keep it under control, but that can pose other challenges. So, with alien species continuing to establish themselves in ecosystems across the world, Thomas stresses that it is still worth trying to control their spread.
“Yes, it’s been happening for a long time, but it’s going to continue to happen, and the ecology will continue to change unless we take steps to arrest it,” he says. “There are real benefits in doing something rather than nothing. If it’s not addressed, then we will continue to see this ever-changing profile.”
To meet IMO requirements, a ballast system should treat all ballast water on uptake to minimise the transfer of alien species.
Unlike most of the competition’s solutions, Wärtsilä Aquarius ballast water management systems hit the problem from two sides, using both ultra-violet (UV) and electro-chlorination treatment solutions.
The UV system is most economical for ballast pumps with a capacity of less than 1000 cubic metres per hour, and the electro-chlorination system is most cost-effective for those with a capacity above 1500 cubic metres per hour.
The Aquarius range of ballast water management systems does not attempt to adjust the level of ballast water treatment, as the quality of water being pumped on board varies, but instead relies on a fixed dose aimed to be sufficient to ensure compliance with the regulation.
“Our approach from the very beginning really was more conservative, I guess,” Thomas says. “We fixed our dose rates at a higher level so that control complexity was minimised. Our focus has been on compliance as well as making sure the customer has peace of mind.”
Wärtsilä’s experience has led it to try to make the system as simple as possible. “When you need to treat the ballast water, you absolutely need the ballast water treatment system to work, and if it doesn’t work, it’s a big problem,” he explains.
Over the last few years, in anticipation of the ratification, new vessels have increasingly been fitted with ballast water management systems, often using designs that have rarely been properly put to the test.
“Many of those effectively are not used at all,” he points out. “I cannot say whether they’re maintained correctly and in accordance with the OEM guidance, but it may be that, when they’re switched on in earnest, some significant problems could occur.”
As the world finally begins to tackle the problem of ballast water, Thomas hopes the advantages of Wärtsilä’s approach will be obvious. “Our approach has been one of partnership with the customer from the beginning. We help him choose the right technology, make sure the system is robust enough to comply with the regulations and provide global service support for maintenance,” he concludes.