Tag Archives: marine scrubbers

How Air Pollution Infiltrates the Seas

A global effort to curb pollution from the heavy fuel oil burned by most big ships appears to be encouraging water pollution instead. A 2020 regulation aimed at cutting sulfur emissions from ship exhaust is prompting many owners to install scrubbing systems that capture pollutants in water and then dump some or all of the waste into the sea.

Some 4 300 scrubber-equipped ships are already releasing at least 10 gigatons of such wastewater each year, often in ports and sometimes near sensitive coral reefs…. The shipping industry says pollutants in the waste don’t exceed national and international limits, and that there’s no evidence of harm. But some researchers fear scrubber water, which includes toxic metals such as copper and carcinogenic compounds called polycyclic aromatic hydrocarbons, poses a rapidly growing threat, and they want to see such systems outlawed.

The emerging debate is the result of a 2020 regulation put into place by the International Maritime Organization (IMO), an arm of the United Nations that works with 174 member states to develop common rules for international shipping. By banning the use of sulfur-heavy fuel oil, the rule intended to reduce pollutants that contribute to acid rain and smog. IMO estimated the rule would slash sulfur emissions by 77% and prevent tens of thousands of premature deaths from air pollution in ports and coastal communities.

But cleaner fuel can cost up to 50% more than the sulfur-rich kind, and the rule allows ship owners to continue to burn the cheaper fuel if they install scrubbers. In 2015, fewer than 250 ships had scrubbers (often to comply with local regulations); last year, that number grew to more than 4300, according to industry figures.

A scrubber system sends exhaust through a meters-tall metal cylinder, where it is sprayed with seawater or freshwater, depending on the type, at rates comparable to gushing fire hydrants, to capture pollutants. In the most popular systems, called open loop scrubbers, seawater is discharged to the ocean after little or no treatment. Other systems retain sludge for disposal on land and release much smaller (but more concentrated) amounts while at sea….Researchers are particularly worried about discharges in areas that IMO has designated as ecologically sensitive. The Great Barrier Reef, for example, receives about 32 million tons of scrubber effluent per year because it’s near a major shipping route for coal. Ships also release scrubber water around the Galápagos Islands….

Ports see substantial discharges, too. Cruise ships dominate those releases, contributing some 96% of discharges in seven of the 10 most discharge-rich ports. Cruise ships typically need to burn fuel in port to continue to operate their casinos, heated pools, air conditioning, and other amenities. Most ports have shallow water, so pollutants are less diluted and can accumulate more rapidly….

Researchers, who are participating in a €7.5 million European effort to study shipping pollution called EMERGE, would like to study how scrubber water affects fish larvae.

But shippers have become hesitant to share samples and data with scientists. “We’re reluctant to give it to organizations which we know have already an established agenda,” says Mike Kaczmarek, chairman of the Clean Shipping Alliance 2020

The ultimate solution is to require ships to use the cleanest fuel, called marine gas oil. In the meantime, 16 countries as well as some localities have banned the most common scrubbers.

Excerpts from Erik StokstadShipping rule cleans the air but dirties the water, Science, May 13, 2021

The International Council on Clean Transportation (ICCT) study, released on April 9, 2021

Scrubbing Sulfur Pollution

From January 2020, the United Nations International Maritime Organization (IMO) will ban ships from using fuels with a sulphur content above 0.5%, compared with 3.5% now.The rules herald the biggest leap in how ships are powered since they switched from burning coal to oil over a century ago, but vessels will still be allowed to use higher-sulphur fuel if fitted with cleaning devices called scrubbers.  Closed-loop scrubbers keep most of the water used for sulphur removal onboard for disposal at port. Open-loop systems, however, remove sulphur coming through a ship’s smokestack with water that can then be pumped overboard.

Years of studies have examined whether open-loop scrubbers introduce into waterways acidic sulphur harmful to marine life, cancer-causing hydrocarbons, nitrates leading to algal blooms and metals that impair organ function and cause birth defects.  The results have largely been inconclusive and the IMO itself has encouraged further study into the environmental impact of scrubbers.

The stated aim of the new IMO measures is to improve human health..  A study in the journal Nature last year found ship emissions with current sulphur levels caused about 400,000 premature deaths from lung cancer and cardiovascular disease as well as around 14 million childhood asthma cases every year.

Singapore and Fujairah in the United Arab Emirates have banned the use of open-loop scrubbers from the start of next year. China is also set to extend a ban on scrubber discharge to more coastal regions. 

Excerpts from Noah Browning, Going overboard? Shipping rules seen shifting pollution from air to sea, Reuters, Oct. 21, 2019

The 2020 Deadline for Fuel Oil

Circle January 2020 on your calendar for what could be a major disruption to the energy market and a jolt to the global economy.The origin of the problem isn’t some oil cartel’s machinations, a looming war or even a technological shift — it is a bureaucratic body that few people have heard of: the International Maritime Organization. Just 30 months from now the cargo vessels that are the lifeblood of global trade will be required to cut the sulfur content in their fuel from 3.5% to 0.5%.

Ships move more than 10 billion tons of cargo a year and do it far more efficiently than road or rail, but it comes at a high cost in terms of overall pollution because ships use fuel oil, which is just about the cheapest, dirtiest stuff to come out of refineries. About 9% of all sulfur dioxide emitted globally comes from ships, contributing to acid rain and many premature deaths annually. Even the new cap is 500 times the sulfur content of most road diesel.

Even with significant investment, refiners may not be ready and ships may have to burn more expensive marine diesel.”Marine diesel affects land diesel which affects jet fuel which affects gasoline,” explains Mr. Tallett. That could cause the prices of those fuels to go up by 10% to 20%.

The only solution may be to simply refine more oil, which means increasing overall demand, to get enough low-sulfur fuel out of the world’s refineries. The International Energy Agency worried about the impact in a February 2017 report, yet it assumes many ships will install marine scrubbers to clean the dirty fuel and that refiners will add units to reduce sulfur content — both expensive propositions.

Excerpts from High Seas are to Deliver a Shock to Energy Sector, Wall Street Journal, June 7, 2017