Memorandum submitted by Symphony Environmental
(Waste 57)
Symphony is a British company which has since
2000 been developing and supplying oxo-biodegradable plastic technology,
which it markets worldwide under the well-known "d2w®"
trade mark.
We will specifically address issues mentioned in
items 3, 5, 6, 7, and 9 of the Committee's terms of reference
after the following observations on the role which oxo-biodegradability
can play in a strategy to deal with plastic waste.
Whilst the benefits of low cost, light weight,
strength, imperviousness to gas and water, transparency, sealability,
and printability are highly regarded, the very strength and durability
which makes plastic such a useful and economic material can be
a major problem when disposal is required.
Science has now found the answer to this problem—oxo-biodegradable
plastic.
It is important to distinguish between the different
types of biodegradable plastic, as their costs and uses are very
different.
The two main types are oxo-biodegradable and
hydro-biodegradable. Hydro-biodegradable is by far the more expensive.
In both cases degradation begins with a chemical process (oxidation
or hydrolysis), followed by a biological process. Both types emit
CO2 as they degrade, but in landfill hydro-biodegradable will
emit methane, which is a much more powerful greenhouse gas. Both
types are compostable in-vessel, but only oxo-biodegradable can
be recycled in the normal plastic waste stream. Oxobiodegradable
plastic can itself be made from recyclate.
1. OXO-BIODEGRADABLE
PLASTIC
A very small amount of d2w pro-degradant additive
is introduced into the manufacturing process of normal plastic
products. Degradation begins when the programmed service life
is over (as controlled by the additive formulation). A typical
d2w carrier-bag will be serviceable for 18 months, but service
life can be extended or reduced as required. It will typically
be re-used several times, sometimes as a bin-liner, before being
discarded. There is little or no additional cost, as d2w products
can be made with the same machinery, raw material, and workforce
as conventional plastic products.
It is important to note that oxo-biodegradability
is not primarily designed as a disposal option. It is intended
as a low-cost precaution against plastic waste which finds its
way into the environment, where it can otherwise last for many
decades. If however, oxo-biodegradable plastic were to be collected
and placed under a net with access to light and air it would degrade
in a short time to nothing more than water, CO2, humus and trace
elements, leaving no harmful residues. There would be no need
for landfill or incineration.
Degradable plastic products of both types have
been dispensed by supermarkets for more than four years, and there
is no evidence that people dispose more carelessly of them and
they have not been encouraged to do so.
But suppose for the sake of argument that 10%
more were discarded. If 1,000 conventional and 1,100 oxo-biodegradable
bags were left uncollected in the environment, 1,000 conventional
bags would remain in the rivers, streets and fields for decades,
but none of the oxo-biodegradable bags would be left at the end
of the short life programmed into them at manufacture.
Education is important, but there will always
be people who deliberately or accidentally discard their plastic
waste. What will happen to all the plastic waste that will not
be recycled or will not be incinerated, and instead will litter
the countryside and the oceans—would it not be better if
the discarded plastic were all oxo-biodegradable?
Conversion of all short and medium-life plastic
products to oxo-biodegradability should be encouraged by Government,
and we have made a written submission to London Councils in relation
to their proposal on plastic bags which is currently before Parliament.
The first major country to adopt oxo-biodegradability in legislation
is Brazil, where there are laws at State and City level requiring
conversion to oxo-biodegradable.
D2w oxo-biodegradable plastic will be consumed
by bacteria and fungi after the additive has reduced the molecular
structure to a level[159]
which permits living micro-organisms access to the carbon and
hydrogen. It is therefore "biodegradable."[160]
This process continues until the material has biodegraded to nothing
more than CO2, water, and humus, and it does not leave fragments
in the soil. D2w Oxo-biodegradable plastic passes all the usual
ecotoxicity tests, including seed germination, plant growth and
organism survival (daphnia, earthworms).[161]
Specimens of d2w oxo-biodegradable LDPE (low-density
polyethylene) and PP (polypropylene)[162]
and PS (polystyrene)[163]
have been tested and demonstrated under the conditions of test
to be fully compliant with the current European food contact material
requirements.[164]
And US Food & Drugs Administration requirements[165].
Degradation of a d2w polyethylene specimen consistent
with changes expected by American Standard D 6954-04 has been
demonstrated.[166]
ASTM D 6954-04 is the Standard Guide for Exposing and Testing
Plastics that Degrade in the Environment by a Combination of Oxidation
and Biodegradation.
D2w Oxo-biodegradable plastic products are now
being used by leading retailers in the UK and around the world[167].
In May 2007 the Periodical Publishers Association of the UK[168]
recommended to its members that oxo-biodegradable film should
be used for wrapping their newspapers and magazines for distribution.
Unlike PVC, the polymers from which oxo-biodegradable
plastics are made do not contain organo-chlorine. Nor do oxo-biodegradable
products contain PCBs, nor do they emit methane or nitrous oxide
even under anaerobic conditions. Oxo-biodegradable plastics do
not contain "heavy metals.[169]
" The metal salts used in oxo-biodegradable plastics are
trace-elements necessary for healthy plant and human growth.
Oxo-biodegradable plastics are currently made
from naptha, which is a by-product of oil-refining, and oil is
of course a finite resource. However, this by-product arises because
the world needs fuels and oils for engines, and would arise whether
or not the by-product were used to make plastic goods.
Therefore until other fuels and lubricants have
been developed for engines, it makes good environmental sense
to use the by-product, instead of wasting it by "flare-off"
at the refinery and using scarce land and water resources to make
plastics.
2. HYDRO-BIODEGRADABLE
PLASTICS
Plastics in this category normally have a high
starch content and it is therefore said that they are made from
renewable resources. However, many of them contain up to 50% of
synthetic plastic derived from oil, and others (eg some aliphatic
polyesters) are entirely based on oil-derived intermediates. Genetically-modified
crops may also have been used in the manufacture of hydro-biodegradable
plastics.
Hydro-biodegradable plastics made from crops are
not genuinely "renewable" because the process of making
them is itself a significant user of fossil-fuel energy and a
producer therefore of greenhouse gases. Fossil fuels are burned
in the autoclaves used to ferment and polymerise material synthesised
from biochemically produced intermediates (eg polylactic acid
from carbohydrates etc); and by the agricultural machinery and
road vehicles employed. Also by the manufacture and transport
of fertilisers and pesticides.
An impossible amount of land and water would
be required to produce sufficient raw material to replace conventional
plastic products.
Three recent articles in the international press
have drawn attention to the danger of using "renewable"
resources derived from plants as a substitute for petroleum products.
They focus on the use of corn and palm oil to make "biofuels"
for motor vehicles, but the same danger arises from the use of
corn and other agricultural products to make hydro-biodegradable
plastics.
The International Herald Tribune wrote on
31st January 2007 "Just a few years ago politicians and green
groups in the Netherlands were thrilled by the country's adoption
of "sustainable energy" by coaxing electricity plants
to use biofuel. Spurred by government subsidies, energy companies
designed generators that ran exclusively on this fuel, which in
theory would be cleaner than fossil fuels because it is derived
from plants.
But last year, when scientists studied plantations
in Indonesia and Malaysia, this green fairy-tale began to look
more like an environmental nightmare. Rising demand for palm oil
in Europe caused the razing of huge tracts of southeast Asian
rain forests, and the over-use of chemical fertilisers there.
Worse still, space for the plantations was often created by draining
and burning peat land, which sent huge carbon emissions into the
atmosphere.
In Mexico on 25th January the financial newspaper
"24 ORE" asked "Food or fuel? Is maize better
on the table as tortillas or in the tanks of cars, converted into
ethanol and then bio-fuel? The price of the cereal has doubled
in a year because of the high demand for ethanol obtained from
maize to produce bio-fuels. It has created a real food crisis
because the price of tortillas has increased greatly. They used
to cost seven pesos per kilo but now exceed 18 pesos. Tortillas
are the basic element of the Mexican diet.
According to the Earth Policy Institute, "The
trade off between food and fuel risks creating chaos in the world
market of food products" and they predict that shortages
and higher food prices will lead to starvation and urban riots
Business Week 5 Feb 2007 edition "The
rise in the price of corn that's hurting US pig farmers isn't
caused by any big dip in the overall supply. In the U.S., last
year's harvest was 10.5 billion bushels, the third-largest crop
ever. But instead of going into the mouths of pigs or cattle or
people, an increasing slice is being transformed into fuel for
cars. The roughly 5 billion gallons of ethanol made in 2006 by
112 U.S. plants consumed nearly one-fifth of the corn crop."
US chicken producers are also being hit. The industry's feed costs
are already up $1.5 billion per year. Ultimately, these increases
will be passed on to consumers, and there could be dramatic inflation
in food costs.
Hydro-biodegradable plastics will not readily
degrade unless they are in a highly-microbial environment, and
will instead merely fragment for example in a field or a street.
Specific issues in Committee's Terms of Reference
3. WASTE MINIMISATION
Compare different packaging materials, according
to criteria like weight, energy and volume of reduction. If we
take 100% as a starting point—without plastic we would have
about 484% in terms of weight. In terms of energy consumption,
with plastics if we take 100%, without plastic we will have around
300%. The same in volume of waste—with plastic and without
plastic we have almost 300%.[170]
Paper Bags
A stack of 1,000 new plastic carrier bags would be
around 2 inches high, but a stack of 1,000 new paper grocery bags
could be around 2 feet high. It would take at least seven times
the number of trucks to deliver the same number of bags, creating
seven times more transport pollution and road congestion.
Also, because paper bags are not as strong as plastic,
people may use two or three bags inside each other. Paper bags
cannot normally be re-used, and will disintegrate if wet.
The process of making paper bags causes 70% more
atmospheric pollution than plastic bags. Paper bags use 300% more
energy to produce, and the process uses huge amounts of water
and creates very unpleasant organic waste. When they degrade they
emit methane and carbon dioxide.
Re-usable Bags
Long-term re-usable shopping bags are not the
answer either. They are much thicker and more expensive, and a
large number of them would be required for the weekly shopping
of an average family. They are not hygienic unless cleaned after
each use. Whilst sometimes called "Bags for Life" they
have a limited life, depending on the treatment they receive,
and become a very durable form of litter when discarded.
Shoppers do not always go to the shop from home,
where the re-usable bags would normally be kept, but for those
who believe in long-term re-usable bags, they can be made from
extended-life oxo-biodegradable plastic and will last for five
or more years.
4. COMPOSTING
Composting is the disposal option for a very
small part of the plastic waste stream. Indeed, as composters
cannot readily distinguish between oxo-biodegradable, hydro-biodegradable
and conventional plastic, they prefer to exclude plastic of any
kind.
However, if composting is the desired solution, organic
waste can be put into oxo-biodegradable plastic sacks in homes,
restaurants, hospitals, etc. and put straight into an industrial
composting plant, so smells, disease transmission by flies, and
handling hazards to humans are effectively minimised. The bags
do not need to be opened and disposed of separately.
Oxo-biodegradable plastic does not degrade quickly
in low temperature "windrow" composting, but it is ideal
for "in-vessel" composting at the higher temperatures
required by the animal by-products regulations. Indeed it is likely
that windrow composting will soon have to be phased out.
Oxo-biodegradable plastic is particularly useful
for "back-of-store" use in supermarkets, as waste bread
and other products wrapped in oxo-biodegradable plastic packaging
can be put into oxo-biodegradable sacks and put straight into
a suitable composting plant.
Another problem with EN 13432 is that it requires
almost complete conversion of the carbon in the plastic to CO2,
thus depriving the resulting compost of carbon, which is needed
for plant growth, and wasting it by emission to atmosphere. Since
oxo-biodegradable plastic (unlike the starch-based alternative)
releases its carbon slowly, it produces high quality compost.
The 11th September 2003 Report to the Australian Government by
the Nolan-ITU Consultancy concludes that:
"oxo-biodegradable plastics based on polyolefins
contribute to the amount and nutritive value of the compost because
much of the carbon from the plastic is in the form of intermediate
oxidation products, humic material and cell biomass. This is in
contrast to plastics such as hydro-biodegradable polyesters (eg
starch-based) that biodegrade at rates comparable to purified
cellulose. At the end of the commercial composting process, all
of the carbon from the latter has been converted to CO2 so there
is a contribution to greenhouse gas levels but not to the value
of the compost."
Oxo-biodegradable plastic can be tested according
to American Standard ASTM D6954-04 for Plastics that Degrade in
the Environment by a Combination of Oxidation and Biodegradation.
It is claimed by the hydro-biodegradable industry
that a product is not compostable unless it satisfies European
standard EN 13432.[171]
This standard applies only to plastic packaging, and was
written before oxo-biodegradable plastics became popular. It is
not appropriate for testing oxo-biodegradable plastics because
it is based on measuring the emission of carbon dioxide during
degradation. Hydro-biodegradable plastic is compliant with EN
13432, precisely because it emits CO2 (a greenhouse gas) at a
high rate.
If a leaf were subjected to the CO2 emission
test included in EN13432 it would not be considered compostable,
or even biodegradable.
EN 13432, does not require that plastics biodegrade
during and after composting within any particular time-scale.
Paragraph 5 of EN 13432 says: "It is important to recognise
that it is not necessary that biodegradation of packaging material
or packaging be fully completed by the end of biological treatment
in technical plants but that it can subsequently be completed
during the use of the compost produced"
Conversion of organic materials to CO2 at a
rapid rate during the composting process is not "recovery"
as required[172]
by the European Directive on Packaging and Packaging Waste (94/62/EC
as amended), and should not be part of a standard for composting.
Nature's lignocellulosic wastes do not behave in this way, and
if they did the products would have little value as soil improvers
and fertilisers, having lost most of their carbon.
The Directive does NOT require that when a packaging
product is marketed as "degradable" or "compostable"
conformity with the Directive must be assessed by reference to
EN13432. In the first place although the Directive provides[173]
that conformity with its essential requirements may be presumed
if EN 13432 is complied with, it does not exclude proof of conformity
by other evidence, such as a report from a reputable testing institution.
Indeed Annex Z of EN13432 itself says that it provides only one
means of conforming with the essential requirements.
Packaging made from oxo-biodegradable plastic
complies with para. 3(a), (b) and (d) of Annex II of the Directive.
This Annex specifies the essential requirements for the composition
and the reusable and recoverable, including recyclable, nature
of packaging.
Oxo-biodegradable plastic satisfies para. 3(a)
because it can be recycled. It satisfies para. 3(b) because it
can be incinerated. It satisfies para. 3(d) because it is capable
of undergoing physical, chemical, thermal or biological decomposition
such that most of the finished compost ultimately decomposes into
carbon dioxide, biomass and water.
5. METHANE
As noted above, hydro-biodegradable plastic
emits methane deep in landfill where conditions are anaerobic,
and hydro-biodegradable packaging should not therefore be encouraged.
Oxo-biodegradable plastic does not emit methane under
any conditions
6. HEAT RECOVERY
In some countries, incineration is popular,
and the necessary equipment is in place. Oxo-biodegradable plastic
can be incinerated with energy recovery in the same way as conventional
plastic, and has a higher calorific value than the hydro-biodegradable
alternative.
7. RECYCLING
Oxobiodegradable plastic can be made from recyclate,
but Hydro-biodegradable plastic cannot.
Oxo-biodegradable plastics can be recycled with other
clean commercial polyolefin wastes, provided that regard is had
to the inclusion rate and the level of degradation, and that stabilisers
are added where necessary. Hydro-biodegradable plastics cannot
be recycled with other polymer components of waste. They would
therefore have to be extracted from the waste stream and treated
separately, at prohibitive cost.
It is difficult for recyclers to physically
distinguish the two types of plastic so, the more that hydro-biodegradable
plastic gets into the waste stream the greater the problem for
recyclers. For this reason also they should not be encouraged.
Hydro-biodegradable plastics have been called
into question by recyclers.[174]
Addressing the Local Authority Recycling Advisory Committee conference
in November 2006 Recoup's[175]
project manager warned that starch-based plastics could "have
a negative impact on plastics recycling as a whole". With
compostable plastic packaging made from degradable starch-based
materials and traditional [and oxo-biodegradable] plastics from
oil-based ones, the fear is that bioplastics will increasingly
find their way into the plastics recycling stream—impacting
on quality and un-doing the work done on raising public awareness
of plastics recycling."
Symphony Environmental
January 2008
159 sub 40,000 Daltons Back
160
Oxo-degradation is defined by TC249/WG9 of CEN (the European Standards
Organisation) as "degradation identified as resulting from
oxidative cleavage of macromolecules." And oxo-biodegradation
as "degradation identified as resulting from oxidative and
cell-mediated phenomena, either simultaneously or successively." Back
161
Organic Waste Systems NV Belgium-Reports 1812/93224 8th Mar 2006.
See also G. Scott and D.M. Wiles, Degradable Polymers: Principles
and Applications, Kluwer, 2002, Chapter 13, Section 9.11,
page 472, et seq. Back
162
RAPRA report 19th March 2007. RAPRA Technology Analytical Laboratories
are accredited by the United Kingdom accreditation authorities
as meeting the requirements of International Standards Organisation
norm no.17025. Back
163
RAPRA report 12th April 2005. Back
164
Directive 2002/72/EC (as amended 2004/19/EC). Back
165
RAPRA confirmation 14th November 2007. Back
166
RAPRA Report 7th June 2006. Back
167
In September 2007 the Commercial Packaging Manager of the Co-op
said "I am happy to say that we are using oxobiodegradable
polythene films for direct food contact applications. We currently
use these materials for pre-packed produce, self serve produce,
pre-packed bread, frozen vegetables and fresh turkeys as well
as for carrier bags. The approval for use has been based on the
very strict EU requirements under EU Directives 2002/72/EC and
2004/19/EC relating to plastic materials and articles intended
to come into contact with foodstuffs. We have been using these
materials for food contact use since 2004." Back
168
www.ppa.co.uk/cgi-bin/go.pl/news/article.html?uid=11657 Back
169
The term "heavy metal" has never been defined by any
authoritative body. Over the 60 years or so in which it has been
used in chemistry, it has been given such a wide range of meanings
by different authors that it is effectively meaningless . . .
. . . Even if the term "heavy metal" should
become obsolete because it has no coherent scientific basis, there
will still be a problem with the common use of the term "metal"
to refer to a metal and all its compounds. This usage implies
that the pure metal and all its compounds have the same physicochemical,
biological, and toxicological properties. Thus, sodium metal and
sodium chloride are assumed by this usage to be equivalent. However,
no one can swallow sodium metal without suffering life-threatening
damage, while we all need sodium chloride (salt) in our diet.
(Pure Appl. Chem., Vol. 74, No. 5, pp. 793-807, 2002). Back
170
Prof. Emo Chiellini, Professor of Fundamentals of Technologies,
University of Pisa. Simpósio Internacional de Plásticos
Degradáveis e Biodegradáveis 6th June 2007. See
also Polymers and the Environment, 1999, Chapter 4, Management
of Polymer Wastes, p. 78-81 and Degradable Polymers 2nd edition,
Chapter 1). Back
171
or its US equivalent ASTM 6400. There are also other national
equivalents eg in Australia. Back
172
Annex II para. 3. Back
173
Article 9(2). Back
174
Materials Recycling Week 20 Nov 2006. Back
175
RECOUP (www.recoup.org) is the national charity developing plastics
recycling in the UK, promoting best practices and providing educational
and training tools. Back
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