Biofouling: an opportunity ripe for the taking

“Ballast water treatment is basically trying to clean water with particles and do that on board a ship; biofouling is taking particles from a ship, but with the water in the local port.” This is how ECOsubsea chief executie Tor M Østervold explains the key difference between ballast water treatment and biofouling.

The two concepts have become somewhat intertwined in recent years, as ballast water has been subject to severe and expensive legislation, while biofouling – which ostensibly deals with similar issues of invasive species and position – has escaped with only industry guidelines to govern its path.

However, biofouling is far more than a current replica of the problems previously addressed by ballast water treatment. The problems with biofouling go beyond pollution and aquaculture damage because when a hull is fouled it loses its efficiency. As such, it requires more fuel to power it through the water, resulting in more pollution and cost to the owner.

Addressing biofouling requires recognition of these issues, combined with innovative techniques and solutions. There is no ‘one-size-fits-all’ approach.

A strong advocate of condition-based maintenance, Mr Østervold explains that different cleaning techniques result in huge disparities in ship operations.

He has seen vessels build up 8 kg of biofouling a day and cites a continuous trading, 200-m long roro ferry with over 1,000 kg of dried biofouling that had built up over a year; he also notes two similar cruise ships on the same trade, employing the same coating, but where the approach to biofouling differed: one did not require cleaning for three years, while the other had to be cleaned eight times in three months.

ECOsubsea has been involved in cleaning 600 vessels to date, recovering some 90,000 kg of biomass in the process. This process has also had a significant effect on the fuel efficiency of the ships involved. “About 3M tonnes of CO2 has been saved from these vessels during the treatment process when they are loading and discharging into port,” he says.

Mr Østervold explains this waste can be put to good use once removed from the vessel, resulting in the double benefit of more efficient operations and less pollution on land and at sea. “The bio-mass recovered at our facilities at the Port of Southampton has not only had a great effect on the fuel efficiency of the vessels – about 3M tonnes of CO2 two has been saved – but in Southampton the bio-mass waste is being used to fuel bio-gas production, making green electricity for the households around the port.”

He believes collaboration is key to releasing the many efficiencies currently tied up in biofouling and explains that following its successes in Europe, ECOsubsea will soon start scaling the technology in key ports around the world. 

“We have done a lot so far in terms of biofouling clean-up,” he says, “but we think there is still a great deal left to do. Our ambition is to clean 10,000 ships annually, which would mean 1M tonnes of biofouling would be collected.”

This translates into 50-55M tonnes of CO2 saved. Emphasising the enormity of the savings involved, he notes “That is the same amount of CO2 as Norway emits per year.”