No clear solution for disposing of sludge produced by scrubbers

The Alaska Department of Environmental Conservation is investigating whether this black material was the result of improper cruise ship discharges.
The Alaska Department of Environmental Conservation is investigating whether this black material was the result of improper cruise ship discharges. Source: Provided by the City of Ketchikan

The cruise industry might have tamed an air pollution problem only to create the potential for new contamination of the waters in which its vessels sail.

With the growing use of exhaust gas cleaners, known informally as scrubbers, cruise lines have successfully cleansed the plumes from the stacks of their ships of harmful sulfur dioxide emissions.

Since 2015, vessels sailing in North American waters within an internationally adopted Emission Control Area have had to cut sulfur emissions to 0.1%, removing 920,000 tons of sulfur and 90,000 tons of soot from the air each year.

Using scrubbers has saved cruise lines tens of millions of dollars that they otherwise would have had to spend on low-sulfur fuel.

But now questions are being raised about where all the pollution that’s being removed from cruise ship exhaust is ending up.

In at least one case, officials in Ketchikan, Alaska, have sought to learn if the sulfur sludge ended up being piped overboard in their port.

On July 27, port employees saw a discharge coming from the Star Princess, which was docked at one of the Ketchikan berths. Photos show darkened splotches in the water. One shows a patch of lumpy black material floating near a piling.

Port authorities notified the ship of the discharges, and the scrubber system was turned off, according to a city memo. At a city commission meeting, residents complained about the pollution of the harbour.

The city referred the photos and the information it had collected to the Alaska Department of Environmental Conservation (ADEC) and said the department would be investigating the incident.

A program officer at the agency, which is in charge of monitoring cruise ship discharges statewide, said he couldn’t comment on any preliminary findings or potential investigations.

“The department’s cruise ship program has a goal to respond to all complaints or concerns we receive,” officer Edward White said. “This often includes following up with the ship operator to request and review records and obtain additional information.”

The most crucial question is: What was in those discharges?

Exhaust gas is “scrubbed” with water, either salt or fresh, which when sprayed through the rising exhaust, causes the sulfur to dissolve in the water. The scrubbing also removes particles such as soot, incompletely burned oil, traces of heavy metals and ash.

It is permissible for ships to discharge wash water that contains sulfates, once the water has been treated for acidity, turbidity and other factors. But the sludge separated from the water cannot be discharged or incinerated at sea. It has to be kept onboard for land disposal in a port.

Princess Cruises, in a statement, asserted that the discharges from the Star Princess on July 23 were “within the regulatory guidelines relative to the acceptable discharge from exhaust-gas cleaning systems.”

It said that onboard monitoring systems confirmed that no waste water containing oil or other residue had been discharged.

“Our experts believe what was viewed and photographed is most likely sea foam discoloured by natural microorganisms such as algae in the seawater, which is commonly experienced in northern climates in the summer season,” Princess said.

The issue of what to do with scrubber residue, or sludge, is set to grow in importance as tighter restrictions on sulfur are set to kick in worldwide in 2020. The maximum sulfur content of marine fuel will be cut from 3.5% to 0.5%, setting the stage for thousands of ships to install scrubbers to save costs.

This year in Alaska, 23 cruise ships are using scrubbers on 401 cruises, according to the ADEC. They produce a surprising amount of waste: An average seven-day cruise on a big ship can yield two to five tons of scrubber sludge, said Brian Salerno, senior vice president for maritime policy at CLIA.

For now, at least, that weight has to be carried until the end of the cruise.

“I’m not aware of any reception facilities in Alaska,” Salerno said. “They tend to be smaller ports, more remote ports. My understanding is [a ship’s crew] would retain the sludge onboard until they get to a larger port,” such as Vancouver, Seattle or Los Angeles, he said.

Princess has been cited in the past for improper disposal of other kinds of waste. Last year, Princess paid a $40 million penalty and pleaded guilty to seven felony counts for illegally dumping oil-contaminated waste overboard, then falsifying official logs to conceal the discharges, according to the U.S. Department of Justice.

Princess remains on probation for five years as part of its sentence. As for that incident, Princess senior executives blamed shipboard engineers who ran clean water through sensors meant to measure oily waste discharge levels at sea.

Norwegian Upholding Cruise Industry’s Clean Air

Norwegian Cruise Line, Norwegian SunPHOTO: Norwegian Cruise Line’s Norwegian Sun. (photo courtesy of Norwegian Cruise Line)
The cruise industry is collectively striving for cleaner air standards internationally, and Norwegian Cruise Line is doing its part by having environmentally enhanced its Norwegian Jade and Norwegian Sun.

“We have both a moral responsibility and business imperative to sustain the places we sail and the communities that support our industry,” said Cindy D’Aoust, president and CEO, Cruise Lines International Association (CLIA), in a press release.

“Through innovative and state-of-the-art air emissions programs, we make clean ocean air one of our top priorities.”

Norwegian specifically retrofitted the Jade and Sun with a new Exhaust Gas Cleaning system. Combined with the line’s Sail & Sustain environmental program, the technology will help to dramatically lower air emissions.

The exhaust scrubbers remove sulfur oxide and particulate matter prior to emissions exiting the ships’ smokestacks. Each vessel received five such scrubbers, one per engine. Together, they can reduce sulfur by up to 99 percent and 85 percent of particulates. Combined, the Jade and Sun will lessen the equivalent of around 3,000 tons of Sulfur Oxide, SOx, gas during the coming years.

As a whole, CLIA Cruise Line Members—Norwegian included—are always investing in new ship designs and innovative technologies. One objective is to reduce new marine vessel CO2 emissions by 30 percent come 2025. Other goals include lowering fuel consumption by 5 percent by applying hull paints with special non-toxic coatings and producing emissions-free energy via solar panel installations.

To such ends, the industry has collaborated with the likes of the International Maritime Organization (IMO) in order to regulate environmental standards. It has also gathered NGOs and maritime stakeholders to share air emission reduction concepts.

Port destinations additionally partner with cruise brands to better the environment as the Port of Seattle has. The facility has even awarded lines for their shared commitment towards green initiatives.

“We at the Port of Seattle observe year after year the cruise industry’s commitment to reducing emissions while in port by using shore power and exhaust gas cleaning systems,” said Port of Seattle Commissioner John Creighton, in the release.

“As part of our port community, cruise lines share our goals to reduce maritime-related emissions while maintaining a vibrant harbor. We look forward to our continued relationship with the industry and partnering on our mutual efforts to protect Seattle’s natural environment and air.”

Within the Norwegian fleet, the Jade and Sun represent two of what will soon be eight ships that have installed the scrubber technology. The Norwegian Escape, Norwegian Gem, Norwegian Joy, Norwegian Pearl and Pride of America already utilize the system, and the upcoming new Norwegian Bliss will launch with it in June 2018.

Norwegian is on its own way to achieve its MARPOL Annex VI compliance objective to lower its global sulfur cap from 3.5 percent to 0.5 percent by 2020.

Besides clean air goals, the line’s Safety and Environmental Protection Policy calls for lessening overall operational impact on the environment, disposing of waste according to domestic and global regulations, the recycling and reuse of materials, and targeting other means to improve the environment via management.

All of this is to say the cruise industry—although environmentally imperfect at times—is making concerted efforts to be the best it possibly can be. Provided brands like Norwegian Cruise Line continue to do their part and uphold the standards they themselves pioneer, the earth and travelers will thank them.

For more information on the industry’s environmental efforts, visit

Royal Caribbean to Retrofit 19 Ships with Scrubbers

Royal Caribbean to Retrofit 19 Ships with Scrubbers


Royal Caribbean Cruises Ltd. will retrofit 19 of its ships with advanced emissions purification (AEP) systems. These systems, also known as scrubbers, will remove more than 97% of the sulfur dioxide emissions generated by the ships’ diesel engines.

The company says the move will position RCL ahead of all forthcoming International Maritime Organization Emission Control Area emissions standards, and will ensure compliance with existing European Union standards. Additionally, the decision to install AEP systems instead of switching to a fuel with a lower sulfur content will ensure that RCL’s ships can be compliant everywhere they sail, as availability of lower-sulfur fuels is limited.

“AEP technology for maritime vessels is very new, and we expect that by utilizing multiple technological solutions to accommodate the differences among our ships, additional development will ultimately help industrialize AEP technology even more, which will benefit not only RCL but also the larger maritime industry,” said Adam Goldstein, President and COO, Royal Caribbean Cruises Ltd.

The company faced significant challenges in order to accommodate the AEP systems on its existing ships – some pieces of which can be as large as a school bus, an entire system having an operational weight of several hundred tons of equipment and liquids.

“A retrofit project of this size and complexity – and the scale and intricacy of the research, planning, and design required – is unprecedented for our company, and has required a very systematic process and involved the world’s leading expertise in this field,” said Harri Kulovaara, Executive Vice President, Maritime, Royal Caribbean Cruises Ltd.

RCL contracted two different AEP technology suppliers, Swedish company Alfa Laval and Finnish company Wartsila. Additional companies are being hired to execute the installations.

Beginning in January 2015, installation will take place on 13 Royal Caribbean International ships and six Celebrity Cruises ships, during scheduled dry-dockings and while ships are in service. While preliminary work has begun on several of the ships receiving AEP systems, most will take place between 2015 and 2017. Each installation will take approximately eight months.