Why efforts to block invasive aquatic species aboard ships are off to a rocky start | October 10, 2016 Issue - Vol. 94 Issue 40 | Chemical & Engineering News
Volume 94 Issue 40 | pp. 22-24
Issue Date: October 10, 2016

Why efforts to block invasive aquatic species aboard ships are off to a rocky start

Despite ratification of a maritime treaty, confusion still reigns over how to comply
Department: Business
News Channels: Environmental SCENE
Keywords: water, ballast water treatment, electrochlorination, ultraviolet light, testing standards
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Ballast water empties from a cargo ship.
Credit: ShutterStock
Ballast water pours from the hull of a large container ship.
 
Ballast water empties from a cargo ship.
Credit: ShutterStock

Zebra mussels are native to the Black Sea separating Southern Europe from Western Asia. But in the late 1980s, larvae of the fingernail-sized mollusks invaded the Great Lakes between the U.S. and Canada. They did so by hitching a ride in the ballast tanks at the bottom of oceangoing vessels.

Ballast tanks hold millions of liters of water intended to add weight and stabilize ships at sea. The water they take on in one port after delivering goods can be dumped in another port after they load new cargo. In the process, thousands of aquatic microbes, algae, and other animals are transported across the world’s oceans and then released into ecosystems where they are not native. The results can be devastating.

Since establishing themselves in the Great Lakes, the itinerant zebra mussels have clogged power plant and water treatment intake pipes, threatened native mussels, and outcompeted native fish for the algae they both eat. The mussels’ voracious appetite for benign algae is even thought to have contributed to the overgrowth of poisonous algae in Lake Erie that created a drinking water crisis in Toledo, Ohio, in the summer of 2014.

Ballast tanks carry invasive species in other directions as well. The North American comb jelly has traveled with ballast water from the eastern seaboard to the Black and Caspian Seas, contributing to the collapse of local fisheries. The North Pacific sea star has trekked in ballast water from the North Pacific to Southern Australia, depleting local stocks of shellfish.

In 2004, the International Maritime Organization (IMO), a United Nations agency, estimated the global economic impact from invasive aquatic species at $100 billion annually. IMO came out with that estimate the same year it helped negotiate the International Convention for the Control & Management of Ships’ Ballast Water & Sediments.

Finally ratified last month, 12 years later, the treaty is supposed to put an end to future invasions. When it goes into effect in September 2017, ships will need to have some way to keep harmful organisms out of their ballast tanks. Many shipowners will adopt onboard water treatment systems that filter out large organisms and then treat the water to eliminate hitchhikers.

However, marine industry observers question whether shipowners will be able to comply with the treaty in time. Many owners have held off installing systems because of their cost and because U.S. regulators have not yet fully approved any of the treatment systems. Further complicating matters are questions being raised by the U.S. over the tests used to qualify the systems.

Treatment systems already approved by IMO include onboard sodium hypochlorite generators from suppliers such as Evoqua Water Technologies and the peracetic acid injection system developed by German chemical maker Evonik Industries. Other options include ultraviolet disinfection systems made by Calgon Carbon’s Hyde Marine division and Danaher’s Trojan Marinex subsidiary.

The cost of designing and installing treatment systems could approach $60 billion over the next few years for the roughly 60,000 ships that will need them, says Jad Mouawad, a marine engineer who operates an eponymous environmental consulting firm in Norway. He estimates that only about 3,000 ships have installed treatment systems so far.

As shipowners rush to install the ballast systems over the roughly five-year phase-in period, “it will be chaos,” Mouawad says. He expects regulators will ultimately extend the installation deadline an additional five years to give all shipowners a chance to comply.

Shipowners have waited so long to install treatment systems because they have no economic incentive to do so, explains Matt Granitto, ballast water global business manager for Evoqua. “We’re selling coffins: No one wants one, but everyone needs one.”

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Evoqua’s SeaCure system first filters particles larger than 40 µm from incoming ballast water and then adds sodium hypochlorite produced via electrochlorination to kill microorganisms.
Source: Evoqua
A simplified schematic of Evoqua’s SeaCure ballast water treatment system.
 
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Evoqua’s SeaCure system first filters particles larger than 40 µm from incoming ballast water and then adds sodium hypochlorite produced via electrochlorination to kill microorganisms.
Source: Evoqua

Ships that don’t have a system will need to install one following their first “dry docking” after the treaty comes into force, Granitto explains. During dry docking, the whole ship is brought out of the water so the submerged portions of the hull can be inspected and cleaned.

Some owners will try to move up their scheduled dry docking before the September 2017 treaty implementation to postpone installations, Granitto says. Others will scrap older ships rather than invest in systems costing anywhere from $250,000 to $2 million, he adds. Still, the recent IMO treaty ratification has driven a 20-fold increase in customer inquiries about installation, he says.

Like other onboard water treatment systems, Evoqua’s SeaCure has two basic stages: filtration and the addition of a biocide. Evoqua’s second stage relies on an onboard electrocatalytic unit to generate sodium hypochlorite from the salt in seawater.

“Filtration gets rid of the big stuff. The second stage kills the small stuff,” Granitto says. Evoqua has a long history of installing electrocatalytic systems on offshore platforms and at power plants to keep cooling water lines clear of biofilms.

“The system works well as long as you have seawater,” Granitto notes. Ships that enter freshwater bodies, such as the Great Lakes, can still use Evoqua’s system by drawing on a separate seawater storage tank.

Whereas systems like Evoqua’s generate treatment chemicals on-site, others require the necessary biocides to be brought on board. Evonik, for instance, has partnered with marine equipment maker TeamTec to develop the Avitalis system, which combines filtration with automated injection of peracetic acid, a hydrogen peroxide derivative.

TeamTec will make, sell, and service the Avitalis system; Evonik will supply the peracetic acid. According to Jürgen Meier, ballast water project director for the chemical maker, peracetic acid works “through oxidative reactions with organisms’ cell walls, proteins, enzymes, and other metabolites.”

Compared with electrochlorination techniques, peracetic acid injection involves lower up-front equipment costs and “requires considerably less electrical power” to operate, Meier says. But shipowners will have to set aside chemical storage space of anywhere between 3 m3 and 50 m3, depending on how often and how much ballast water needs treatment.

Shipowners will replenish peracetic acid stocks when they dock in ports, Meier says, adding that Evonik will have no trouble delivering the chemical as needed to major port warehouses.

Other systems use UV radiation to control unwanted microorganisms. As seawater flows by UV-emitting lamps on the way to the ballast tank, microorganisms are rendered incapable of reproduction, says Mark Kustermans, a marketing manager with UV systems provider Trojan Marinex.

The Trojan Marinex system has received approvals for its effectiveness under IMO rules—as have about 70 or so other ballast treatment systems from a variety of manufacturers. But none of them have been approved by the U.S. Coast Guard, the U.S. regulator responsible for monitoring ballast systems in U.S. waters. The lack of approval has kept shipowners in a quandary about what system to install.

“Only about 10% of oceangoing fleets call on the U.S. in a given year,” Evoqua’s Granitto says. “But most shipowners want the largest possible market, and so they want to install a Coast Guard-approved system.”

Although the Coast Guard enforces a 2012 U.S. rule that mirrors the IMO treaty’s requirements, it applies what it considers more rigorous equipment qualification tests.

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Pipe clogged by an infestation of zebra mussels.
Credit: Peter Yates/The LIFE Images Collection/Getty Images
Close-up view of a split section of pipe clogged by an infestation of zebra mussels, May 1990.
 
Pipe clogged by an infestation of zebra mussels.
Credit: Peter Yates/The LIFE Images Collection/Getty Images

In the case of UV systems, the Coast Guard requires ballast water tests using a fluorescent dye-stain method to determine whether microorganisms are alive or dead. UV system makers say that a more appropriate test is the most probable number (MPN) method, which counts cells capable of reproduction after treatment. It is a widely used method for testing treated drinking water.

The Coast Guard contends that the MPN test is not equivalent to the stain test because it doesn’t measure the efficacy of UV system treatments “to the performance standard required by the regulations.” The Coast Guard insists that tests prove microorganisms are dead and not just unable to reproduce.

The Coast Guard rejected appeals from UV system makers in December 2015 and July. In testimony before the U.S. House Subcommittee on Coast Guard & Maritime Transportation in April, Coast Guard Rear Adm. Paul F. Thomas told representatives, “Ballast water comes from all over the world, so you can’t tailor the treatment system or the efficacy test. So you need a test that is reliable and repeatable for water from anywhere. And that test today is ‘dead,’ not ‘rendered harmless.’ ”

Mouawad argues that the Coast Guard “isn’t being reasonable.” He points to a recent study in the Journal of Phycology by Dalhousie University academics Hugh L. MacIntyre and John J. Cullen that questions the reliability of the Coast Guard’s stain method (2016, DOI:10.1111/jpy.12415). The article asserts that the stain method works for some species but not for others, and so a “dead” standard couldn’t be uniformly guaranteed. Trojan Marinex helped fund the study.

Kustermans of Trojan Marinex contends that the dispute with the Coast Guard isn’t over and predicts that upcoming IMO meetings will discuss test standards and reaffirm support for the MPN method. He expects that the Coast Guard will accept the MPN method and suggests Congress may influence the Coast Guard’s change of heart.

Meeting the Coast Guard current standards with UV disinfection would be costly for ship owners, Kustermans says. Options include reducing water flow past UV lamps and adding more lamps to the system, he says.

The larger space requirement for the enhanced UV systems could turn off owners of vessels where space is at a premium. Mark Riggio, a senior market manager at Calgon Carbon, says UV systems are currently preferred for small and medium-sized ships because of their modest footprint on board.

Since launching its first treatment systems in 1988, Calgon has sold more than 450 UV systems. Counting on some sort of resolution over testing protocols, Riggio expects sales to pick up significantly during the next year.

It is not just UV makers who must satisfy rigorous U.S. testing requirements. Other available systems haven’t been tested appropriately either, Thomas said in his April testimony.

IMO, Thomas said, has conducted studies of approved systems that showed wide variation in “what data were used and how those data were interpreted. ... And they concluded that we really have no certainty that these systems will work reliably and consistently.” The U.S. wants reliable systems in part because of the difficulty of monitoring them once on board a ship.

Although the Coast Guard has not fully approved any systems, it has issued 10,000 extension letters for vessels that were required to install systems between 2014 and 2018. The existence of so many extension letters “is a shipping industry dilemma,” Mouawad says.

Industry observers say the letters add to the confusion over what systems to install and when they will need to be installed. The letters also raise questions about system effectiveness and certification standards.

But what’s worst, they say, is the extension letters are delaying measures to prevent the spread of invasive aquatic species. The technology available now “does the job of treating ballast water effectively,” Mouawad says. Ratification of the treaty was a long time coming, he points out, and countries that have suffered because of alien species are eager to stem the tide. 

 
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