Making the most of a mixed bag - mixed plastics packaging recycling

Packaging Professional magazine
17 Jul 2011
Mixed plastics recycling at Biffa Polymers, Redcar facility, UK. Image courtesy of Biffa

Europe’s first fully integrated mixed plastics packaging recycling facility in Redcar, UK,
looks to sort out a sustainable future for industry. 

Trails of zeros are
growing on debts, suited
types are contorting
into Sino-friendly postures and
the rare earth metals for our
smartphones are resting in
provincial mines. Indeed, the
sprawling influence of China
has become so pronounced
that even our oranges will soon
speak Mandarin.

So, it comes as little surprise
that China is helping to shape
the future of mixed plastics
packaging recycling on this side
of the world. In recent times,
many mixed plastics packaging
recycling facilities have sent their
assorted waste plastic to China
for washing, especially in the
absence of a fully integrated
facility in the UK.

James Donaldson, Technical
Director of Biffa Polymers (part of
the Biffa Waste Group, whose
head office is in High Wycombe,
UK), explains the need for a
change of approach. ‘The low
hanging fruit is gone. So,
the next level is to get the
harder stuff. The Chinese are
being more selective about the
materials they will accept, and it
is getting much harder to
send low-grade material to
them. So, we’re upgrading it
to finish it off in the UK and
make it into a product for the
domestic markets.’

Waste and see

With this in mind, Biffa opened
what it says is Europe’s first wholly
integrated sorting and recycling
facility for mixed plastics packaging
in Redcar this April. The
plant, which received a £1.187m
capital grant from the Waste and
Resources Action Programme,
takes waste mixed plastics,
such as tubs, trays and bottles,
and looks to turn them into fastmoving
consumer goods.

Donaldson says, ‘The traditional
way of [sorting] mixed
plastics is to sort out each
individual [plastics] stream and
wash each one…You need a
huge tonnage of material to
make it worthwhile. What we
have done is wash everything
and then sort it. That allows you
to build a much smaller plant,
with less capital.’

He says that this contrasts
starkly with the approach of
many recyclers in Europe,
who use waste plastics – mainly
the polyolefin fraction – for
cement kilns.

While Biffa will not reveal some
of the specific equipment and
methods used at the plant,
Donaldson says they ‘use
equipment that recyclers without
our background wouldn’t
normally use because it is either
too expensive or they do not
understand it’. However, they
are more forthcoming about the
processes involved.

Full stream ahead

After the bales are opened,
magnets, screens and belt
sorters are used to strip out
contamination and anything
valuable such as metals.

The second stage involves
washing and density separating
using a three-phase centrifuge,
which applies a high-gravity
sink float.

The plastics are divided
into two phases. A polyolefin
mixture (polyethylene [PE] and
polypropylene [PP]) comprises
the light, floating phase, and
a mixture of PET and heavy
polymers constitutes the other.

A tower is then set up for the
lighter phase, which features six
near-infrared spectroscopy and
colour sorters. This splits the
material further into PE and PP.
High resolution air jet nozzles on the sorters are applied to break
the equilibrium.

Having sorted the materials
into polymer type, they are
further filtered into natural
(clear) and jazz (mixed colour
grade) materials.

The resultant streams include
a PP natural and a PP jazz, a
PE natural and a PE jazz, a black
PE and PP mix, a PET jazz
and a high impact polystyrene
sheet jazz.

Shelving plans

Donaldson says material supply
is not an issue, with more than
1,000 tonnes stored in the
Redcar yard and an additional
thousands tonnes stored by
the group. The plastics are
obtained from Biffa’s Materials
Recycling Facilities (MRFs), local
authorities, and commercial
customers in England, Scotland,
Wales and Northern Ireland.

Donaldson underlines the
importance of supply for
companies looking to use mixed
recycled plastics. ‘If you are a
big manufacturer of detergents,
and you want to launch a
recycled product, then you need
a guaranteed and consistent
supply so that they can run as
virgin [plastic].’

Biffa aims to operate at
20,000tpa full capacity by
April 2012, though they have
ambitions for further expansion.
‘My expectation is that once
this plant is fully operational, we
would repeat it at a 40,000 or
50,000tpa size.’

Biffa is currently running
trials for detergent bottle caps,
tubs and piping. Donaldson
foresees a lot of the company’s
compounds to go back onto
the shelves over the next few
months in packaging of hair,
paint and other products. Eventually,
he sees Biffa’s plastics going into high-end products.

The increasing importance
placed on plastics recycling by
Government and industry could
well play into Biffa’s hands. ‘The
risk in most people’s contracts
is the plastics fraction. Certainly,
since we have historically
relied on China, you will find
that both Biffa and other
companies will focus on
plastics,’ Donaldson explains.