Shipping inches closer to ballast water treatment

While the UK works slowly to ratify a convention on the treatment of ballast water, shipping firms are exploring new treatment technologies. It comes as research shows the North Sea is one of the worst affected regions for invasive non-native species.

BP Shipping is in the final stage of getting approval for new oxidation technology developed to treat ballast waters held in ships. It is one of several shipping firms exploring technologies aimed at minimising the risk of transporting non-native, invasive marine species ahead of the introduction of a global convention.

A global assessment of the impact of these invasions has found shipping is the most common way for species to be introduced.1Invasion of non-native species is one of the major threats to European biodiversity.

In the North Sea, one of the world’s worst affected seas according to the assessment (see figure), shipping has been responsible for introducing around 83% of the invasive non-native species causing ecological damage.

One of their key pathways is in ballast water, used to stabilise ships, which is taken on at one port after cargo is unloaded and discharged at another port before the ship receives cargo.

Between 3-5 billion tonnes of this water is transferred internationally each year. At any given time, ballast water tanks have been estimated to carry at least 7,000 marine species with the potential to pose serious ecological, economical and health threats if released untreated into a new environment.

As the volume of sea-borne trade increases, so do opportunities for species introductions. Recent and predicted rises in sea temperatures as a result of climate change (ENDS Report 383, p 28 ) are likely to present new opportunities for warm-water non-native species to successfully breed in new regions, the UK’s Marine Conservation Society fears.

Along UK coast and estuaries, the Chinese mitten crab is one marine species thought to have been introduced in ballast water. An East Asian native, it was introduced into Europe in the 1930s. Recent population increases suggest a new, more invasive variety has since arrived, according to Environment Agency ecologist Trevor Renals. As well as threatening native species such as native crayfish populations, its burrowing can erode sediment banks and undermine flood defence measures.

"There is only one effective management tool: prevention," said Mr Renals. "The marine environment is so vast, so poorly monitored that once you’ve picked it up, the invasion is likely to have already started. If you don’t prevent introduction the chances are you’ve lost the battle before it’s begun." Potential introductions of micro-organisms such as algae and dinoflagellates are also high on the list of concern.

Back in 1992 the UN’s Rio Earth Summit called on international bodies to take action. The International Maritime Organization subsequently agreed the International Convention for the Control and Management of Ships’ Ballast Water and Sediments, adopted in February 2004. A requirement to use IMO-approved systems for treating ballast waters and sediments for new ships with a capacity of less than 5,000 cubic meters takes effect from 2009.

But only three EU member states have ratified the convention: Finland, the Netherlands and Spain. Worldwide the convention has been accepted by about ten countries representing less than 4% of the world fleet’s gross tonnage. This must triple for the rules to enter into force.

Lloyds Register’s environment manager Gillian Reynolds said governments had procrastinated because the technology to treat ballast water was not yet in place. Environmentalists argue that without regulation firms able to develop the technology will not respond.

However, the European Commission has indicated it will place more pressure on states to adopt the convention as part of its EU-wide strategy on invasive alien species. A consultation on this closed Early May.2 The UK Government’s Marine and Coastguard Agency said it has "already made efforts to ratify the Convention at the earliest possible opportunity". It said that technology is expected to be available by 2011 for all ships covered by the Convention. In the meantime, the UK has been working via OSPAR and the shipping industry to develop guidance on the voluntary interim application of standards. This is expected to be launched shortly.

But in the absence of appropriate legislation across Europe, some firms are starting to move to meet the IMO requirements. Ballast water exchange in the open sea, the current "best practice", is not favoured by industry because of safety issues.

Oxidation systems, a potential alternative to chemical-based treatments, appear to be the most favoured approach, with BP Shipping a backer of this technology. It has been working with suppliers to develop an ozone generator which treats water as it enters the ship and again as it leaves it. The technology has just cleared the first stage of IMO testing and is into the second and final stage. Results are expected in July although BP is confident the technology will pass the IMO’s requirements.

Other firms are still considering their options. Evergreen Marine (UK), the world’s third biggest shipping firm, confirmed to ENDS that it was in discussions with suppliers about potential treatment technology but declined to discuss which technologies it had short listed. Shipping firm Maersk said it is also in the process of evaluating technologies.