Shipping companies worldwide have spent billions of pounds installing devices that scrub sulphur from their vessel’s exhaust and dump them in the ocean instead.
Untreated, airborne sulphur fumes can turn into aerosols — which can cause lung and heart conditions — and also can form damaging acid rain.
Regulations from the UN’s International Maritime Organisation that will come into effect next year call for ships using heavy fuel oil to cut their sulphur emissions.
However, a loophole means that most shipping firms are able to use systems that dump this scrubbed waste underwater rather than storing it for safe disposal in port.
This wastewater emission could have a devastating effect on marine habitats and wildlife, experts warn.
According to the Independent, ship classification firm DNV GL report that around 3,750 ships currently or soon to be in service have have had scrubbers installed — but only 23 sport closed-loop scrubbers that safely store extracted sulphur in tanks for safe disposal at port.
Larger vessels such as bulk carriers, container ships and oil tankers have been the quickest to incorporate scrubbing devices, the Independent reported, with these ships having the most powerful engines and historically being the largest polluters.
Ships sporting open-loop scrubbers emit around 45 tons of acidic, contaminated and warm washwater into the oceans for every ton of fuel burned, warn experts from the non-profit International Council of Clean Transportation (ICCT).
These discharges can contain heavy metals — which are known to damage the central nervous system — and polycyclic aromatic hydrocarbons, which are believed to be agents of bladder, liver, lung, skin and stomach cancers.
Meanwhile, increasing oceanic acidity is responsible for killing off corals reefs across the globe.
As they build up, these polluted water emissions have the potential to create toxic sediments around ports, where ships come and go in high concentrations, along with negatively impacting marine wildlife.
WHAT ARE OPEN-LOOP SCRUBBERS?
Scrubbers are devices fitted to the engines of large ocean-going vessels that remove sulphur from heavy fuel oil exhaust fumes.
Although closed-loop scrubbing systems — which store their waste for safe disposal in port — are available, most ships are being fitted with open-loop scrubbing systems.
These will be allowed thanks to an exception intended to promote innovation in the International Maritime Organisation’s new rules — which come into effect next year.
These dump acidic, contaminated and warm washwater overboard.
Rules prohibiting the use of open-loop scrubbers have been introduced by certain regional ports.
For example, the port of Fujairah in the United Arab Emirates banned the use of the devices in its waters in January.
Meanwhile the scrubbers are prohibited within around 14 miles of China’s southern province of Hainan.
The tech is also banned in parts of Belgium, Germany, Ireland and the US.
‘In the North Sea and some parts of the Channel the water quality has already been heavily degraded,’ environmental campaigner Lucy Gilliam told the Independent.
‘Wildlife in these areas is likely to be far more vulnerable to the effects of having ships discharging huge volumes of acidic, polluted, warm water from scrubbers.’
‘As things stand, far too few parameters are covered by the existing IMO criteria for permitted discharge from scrubbers.’
ICCT researcher Bryan Comer told the Independent that the installation of open-loop scrubbers on cruise liners was of a particular concern.
‘About half of the world’s roughly 500 cruise ships have or will soon have scrubbers installed,’ he said.
‘Cruise ships operate in some of the most beautiful and pristine areas on the planet, making this all the more concerning.’
It is predicted that these vessels will consume around four million tons of heavy fuel oil in 2020, which will result in 180 million tons of contaminated scrubber washwater being released in their wake in the same period, the ICCT report.
While the International Maritime Organisation’s member state have signed off on the use of open-loop scrubbers, rules prohibiting their use have been introduced by certain regional ports.
The EU is also encouraging the organisation to develop a uniform set of regulations which cover when and where open-loop scrubbers would be permitted to discharge the wastewaters they generate.
In response, the IMO is presently investigating the environmental impact of open-loop scrubber outputs and told the Independent that it had already ‘adopted strict criteria for discharge of washwater from exhaust gas cleaning systems.’
Per vessel, the installation of a scrubber device typically costs around £1.6–8.2 million ($2–10 million) — amounting to billions of dollars’ worth hardware across the world’s fleets, noted Mr Cromer.
‘If you are conservative and say that ships are spending about $3 million per ship to install scrubbers, at 4,000 ships that’s $12billion dollars of investment in a technology that enables ships to use the world’s dirtiest fossil fuel — heavy fuel oil.’
‘Worse, scrubbers increase fuel consumption by about 2 per cent, increasing carbon dioxide emissions.’
‘Imagine how far $12billion could have gone if it was applied towards developing and deploying technologies for zero-emission vessels.’