Managing the mounting problems of
plastics waste: What can the chemical industry do?
The issue of plastics waste has come centre-stage in recent
times and the chemical industry, which produces the virgin resins that go into
making the myriad articles we have become accustomed to, is being targeted by
consumers, activists and governments alike. New regulations are emerging, in
developed and developing countries, that put restrictions on plastics use, put
greater responsibility on the industry to address the waste management issue,
and dissuade consumers from a ‘use-once-and-dispose’ culture that has come
to be so intimately connected with plastics.
The implications of these developments on the chemical industry
will be considerable. Plastics are a major part of the industry, accounting for
about a third of all sales. But it is this very same industry, more than any
other, that has the wherewithal to rise to the challenge through technological
interventions especially for recycling a greater portion of plastics than now.
An analysis by McKinsey, a consultancy, reveals that such
interventions make eminent business sense, with the potential to turn out
annual profits of as much as $55-bn worldwide by 2030.
More than a marine problem
While plastic waste anywhere is an eyesore, what has caught the
imagination of the public are the images of vast pools of waste circulating in
the oceans, ingested as food by animals and, endemic to India, piling up in
streets and causing havoc by clogging gutters and choking rivers. Frightening
reports of the seas holding more plastic waste than fish if things go unchecked
have shifted consumer sentiment against plastics.
There are several ways to prevent the flow of plastic waste into
water bodies, but the key is technically sound landfill management and robust
design & operation of waste treatment facilities. Implementing these
approaches will take great resolve amongst all stakeholders – governments,
local bodies, industries and consumers. This has been lacking so far, and it is
the hope that this time around the commitment is more resolute and
action-oriented.
While marine plastics pollution grabs headlines, it is just the
tip of the iceberg. Far larger quantities of plastics end up in landfills –
many of them poorly designed – or are incinerated for energy recovery. Just a
piffling 16% of all plastics waste produced globally ends up in reprocessing
chains to make new articles and goods. This is a pity; purely from a
resource-efficiency perspective there is a huge value creation opportunity when
it comes to reusing plastics (or for that matter any other material). This is
even more so in countries (such as India) that are hydrocarbon-deficient and
spend considerable resources importing oil & gas to meet energy demand and
for making all sorts of chemicals.
Recycling options
Recycling plastics can take one of three basic forms: mechanical
recycling, chemical recycling and reprocessing the plastic waste back to its
most basic feedstock. All of these are being done now, but at scales that pale
into insignificance when compared to the quantum of waste generated. This can
be attributed to several reasons including the low levels of waste recovery,
but that will have to change given the growing concerns.
Mechanical recycling, as the name suggests, does pretty much
nothing to the chemical nature of plastic. The process, simply put, pulverises
it to make pellets that can be reused to make articles. One of the key
challenges is to maintain performance of the recyclate; currently, they are
inferior in performance as compared to virgin material, and cannot be used for
demanding applications.
Chemical recycling puts waste plastics through a chemical
process that breaks them down to their monomers, which can then be reused to
make either the polymers once again, or other chemicals. It is relevant,
however, only for condensation polymers that can be unzipped, such as
polyesters (including all-important polyethylene terephthalate), and
polyamides. While this kind of recycling is carried out at reasonable scale –
including in India – there is considerable scope for process improvements.
Recycling back to feedstock requires breaking down the polymer
chains to hydrocarbons by catalytic and/or thermal processes. Of the options
available, pyrolysis has the biggest potential as it can handle a range of
plastics, including mixed-plastic wastes. It is particularly relevant for
packaging waste, which typically contains several layers of disparate plastics
that cannot be stripped off into its components and need to be processed as a
single unit.
Improving collection – greater involvement of the chemical
industry needed
McKinsey estimates that the amount of plastics going into
recycling can be increased five-fold by 2030 to 220-mtpa, if current flows to
landfill and incineration are redirected and capture for recycling improves.
But this will require the strengthening of the first element in the
waste-management chain –collection infrastructure, which in most countries
suffers from lack of scale. The problem in emerging economies, including India,
is that the collection and primary sorting of waste is often done in informal
systems in which individuals pick through waste dumps manually. This does not
lend itself to easy scale-up.
In order to enable scale-up to happen, the chemical industry
must involve itself in the exercise – directly and indirectly. One has only
to look into the aluminium and paper industries wherein well-established chains
for collection, sorting and recycling came to be established only when the
primary producers became involved – either by making investments in or having
ownership of the recycling infrastructure. The chemical industry has so far
been reluctant to be part of the solution, believing, wrongly, that the
benefits plastics bring will result in consumers to be forgiving of the
problems they create.
What can the chemical industry offer?
The industry can contribute by offering new technologies in
areas such as better solvents and additives for washing plastics, as well as
tracing materials that can be added to plastics to facilitate automated
sorting. They can also work with consumer product companies, particularly in
the design of plastics packaging that make for more facile recycling. Consumer
companies are now very eager to reduce their ecological and material
footprints, and have made some bold proclamations in these directions. They
will need all the assistance they can get in achieving these goals and the
chemical industry is well equipped to offer its considerable expertise.
It can help transform all aspects of recycling by upgrading the
quality of mechanical recyclate and enabling process improvements in pyrolysis
and chemical recycling. The good news is that there is some evidence that they
are moving in this direction. Two European petrochemical companies, Borealis
and LyondellBasell, for example, have recently acquired polymer recyling
companies in Europe, while SABIC, the petrochemical giant headquartered in
Saudi Arabia, is active in the more process-driven research needed for chemical
recycling. But much more needs to be done to make impacts on the scale at which
the problem now exists.
Waste as feedstock?
A futuristic scenario could involve chemical companies taking in
used plastics, as it now does hydrocarbons, and turns them into value-added
products. Pyrolysis-treated wastes, being pure hydrocarbons, could be the
starting point for a new kind of petrochemical industry – one that has
conventionally used naphtha or natural gas liquids as feedstock.
Of course, there will be immense technical challenges that the
industry will have to overcome. But these are the kinds of proactive, big and
bold initiatives that will bring back respect and confidence to an industry
that is now diffident and reactive.
- Ravi Raghavan
Chemical Weekly Issue date: 2nd October 2018
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