Page 34 - Plastics News April 2019

internAtionAL news

Ocean Cleanup experts pinpoint failure points, plan fixes

esigners of a floating system to collect plastic marine research institutes and consultants looked at the system
Ddebris from the Pacific Ocean are pointing to two parts and data collected with the Ocean Cleanup staff.
reasons why the system failed: The debris moved faster The group's engineering team is using the latest results
than creators expected, and a weld failed in the plastic to update the system design and prepare for relaunch
pipe system. According to an update on the Ocean Cleanup while other experts look at ways to speed it up so that it
— which combines a floating high density polyethylene retains captured plastic. A sail rig is under consideration.
pipe with a polyester skirt to corral and collect floating The cleanup system will be redesigned and repaired
plastic — project founder and CEO Boyan Slat said floating in California and then relaunched from Hawaii to the
garbage patch's chaotic environment of waves, winds,
currents and drift forces, possibly in a few months. The
engineering team is using these conclusions and results to
update the design and prepare for relaunch. The group is
working with experts at Agru Kunststofftechnik GmbH and
its Georgetown, South Carolina based Agru America Inc.

Tanzania to ban single-use

plastics by July

plastic moved faster than the U-shaped system. "Not only
was the system then moving too slow, but the plastic was anzania plans to ban the
also moving faster than we had predicted." As a result, Tproduction, importation,
the ocean sweeper dubbed System 001 only collected 2.2 sale and use of all single-
tons of plastic for recycling before its structural failure. use plastic bags by July, to
"At times, large amounts of plastic would gather, only help tackle pollution from
for some -- or all -- of it to float out again," Slat said in non-biodegradable waste.
his update. "Plastic was also occasionally observed to The East African nation is
accumulate on the convex side of the cleanup system. the latest country to make
The plastic count within the system did not remain high a formal commitment to
enough for an efficient extraction process." Then, on phase out single-use non-
December 29, 2018, a 26-foot end section (18 meters) of biodegradable plastics, which have been identified
the 2,000-foot long HDPE floater broke off. by the United Nations as one of the world’s biggest
environmental challenges. Of the 9 billion tonnes of
A root-cause analysis shows the structural failure was plastic the world has produced, only 9 percent has been
caused by a stress crack at a point where the collection recycled, according to U.N. estimates. Tanzania will
skirt is welded to the floater pipe. The point is called a join more than 60 other countries that have banned,
dovetail connection. "Because the dovetails were welded partly banned or taxed single-use plastic bags, including
in 1-meter segments, due to the fabrication possibilities China, France, Kenya, Rwanda and Italy. In August
of our supplier, this created a discontinuity, or gaps, 2017, neighboring Kenya introduced one of the world’s
between each weld," Slat said. Plastic beads were used toughest bans on plastic bags mandating four years in
to fill the gaps, but they did not form a high-quality bond prison or a fine of $40,000 for even using one.“The
with the pipe, and the cleaning system fractured at one regulations are ready for publication ... it is possible
of the weld points. An underwater photo of the break that July 1 will mark the end of the use of plastics in
showed concentric rings increasing up through the HDPE the country,” Tanzania’s Environment Minister January
pipe, Slat noted. The broken pieces of System 001 were
towed to Hilo Bay, Hawaii for study. Experts from HDPE Makamba told Parliament on Monday. Makamba said a
pipe and component suppliers, university professors, formal announcement on the ban of single-use plastic
bags in Tanzania would likely be made later this month.

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