There are several options to deal with waste plastics (reuse
and incineration without energy recovery are not regarded
as recycling options here):
• Recycling (high value-added material recovery)
• Down-cycling (low value-added material recovery)
• Back to feedstock recycling
• Energy recovery
Back to feedstock recycling describes thermal or chemical
processes in which plastics are broken down to monomers
or even further, e.g. to CO and H2 (syngas). These
substances can be used again as a feedstock in the synthesis
of new polymers. Pyrolysis and gasification are
processes that can be used for both producing raw materials
for feedstock recycling or for producing fuel (oil or
gas).
9.1.2 Sample collect ion
In order to collect a sample that is large enough to be
subject to a range of analysis, a beach sampling was
commissioned. To make the sample’s consistency as representative
of the North Pacific Gyre marine debris as
possible, the sampling took place on the Hawaiian island
chain, which is located in the North Pacific Gyre. Since
islands are a sink to marine debris, we assumed the consistency
of washed-up debris to be similar to the consistency
of marine debris.